Brain and Gut Plasticity in Mild TBI or Post-acute COVID Syndrome Following Growth Hormone Therapy
Phase: PHASE3
Conditions: Traumatic Brain Injury, Fatigue, Cognitive Impairment, COVID-19
Sponsor: The University of Texas Medical Branch, Galveston

Brain and Gut Plasticity in mild TBI or post-acute COVID syndrome Following Growth Hormone Therapy 
PI: Randall Urban, MD 
 
9-6-22 
 
Title:  Brain and Gut Plasticity in mild TBI or post-acute COVID Syndrome Following Growth 
Hormone Therapy 
 
Principal Investigator: Randall Urban, M.D., Internal Medicine, UTMB 
 
Co-I: Melinda Sheffield-Moore, Ph.D., Internal Medicine, UTMB 
Co-I: Rick Pyles, Ph.D., Pediatrics, UTMB 
Co-I: E. Lichar Dillon, Ph.D., Internal Medicine, UTMB 
 
 
Institution: The University of Texas Medical Branch at Galveston 
Sponsors:  The Moody Endowment 
 
         Sealy & Smith Foundation 
 
Specific Aims 
Increasing evidence suggests the gastrointestinal (GI) microbiome is altered in patients with 
history of mild traumatic brain injury (mTBI). In this project, we propose to characterize the GI 
microbiome in patients with a history of mTBI or post-acute COVID syndrome complex (PASC) in 
comparison to healthy controls. Furthermore, we propose to investigate the potential effects of 
recombinant Human Growth Hormone (rhGH, given as somatropin, a polypeptide hormone 
(GENOTROPIN)) on the GI microbiome, fatigue, cognition, brain activation, and brain morphology 
in individuals with a history of mTBI or PASC.  
 
Specific Aim 1a. To characterize the GI microbiome in patients with a history of mTBI 
compared to controls. - mTBI Baseline vs. Control Baseline - Fecal samples for determination 
of the GI microbiome will be collected monthly from mTBI subjects and healthy controls over 6 
months to examine the diversity of the microbiome within and between groups. Outcomes: 
Genus, species, q-PCR for selected marker organisms. 
 
Specific Aim 1b. To characterize the GI microbiome in patients with a history of mTBI based 
on presence of Prevotella spp. – mTBI Prevotella spp. positive Baseline vs. mTBI Prevotella 
spp. negative Baseline - Fecal samples for determination of the GI microbiome will be collected 
monthly from mTBI subjects over 6 months to examine the diversity of the microbiome within and 
between groups. Outcomes: Genus, species, q-PCR for selected marker organisms 
 
 
Specific Aim 2. To characterize the GI microbiome in patients with a history of post- COVID-
19 syndrome (PASC) compared to arm 2 controls. - PASC Baseline vs. Control Baseline - 
Fecal samples for determination of the GI microbiome will be collected monthly from PASC 
subjects over 6 months to examine the diversity of the microbiome within and between groups. 
Outcomes: Genus, species, q-PCR for selected marker organisms. 
 
 
Specific Aim 3. To determine whether growth hormone therapy-induced changes in fatigue 
and cognition correlate to changes in the GI microbiome. – mTBI/PASC Baseline (month 0) 
vs. mTBI/PASC Month 6 –  Changes in GI microbiome of mTBI or PASC patients will be correlated 
to fatigue/cognition symptom resolution in response to growth hormone treatment. Healthy 

 
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controls will provide control data.  Controls will not receive rhGH treatment. Outcomes: Changes 
in genus, species, Questionnaires (GSRS (GI), MoCA (cognition), BFI and MFSI (fatigue)). 
 
 
 
Secondary Aims and Symptom-Related Outcomes and Assessment of Body Composition 
and Metabolism: 
 
Specific Aim 4a. To determine whether growth hormone therapy alters mood, sleep quality, 
and quality of life. Mood, sleep, and quality of life will be measured at baseline (month 0) and 
month 6. (POMS (mood/QOL), QOL-AGHDA (QOL of growth hormone (GH) deficiency), PSQI 
(sleep), FPQ (food preferences)). 
 4b. To determine whether growth hormone therapy alters body composition 
and muscle function. Skeletal muscle mass, as derived from lean body mass determinations, 
and fat mass will be measured using dual energy x-ray absorptiometry (DEXA) at baseline (month 
0) and month 6. (DEXA, Biodex, 6 min walk). 
 4c. To determine whether growth hormone therapy alters resting energy 
expenditure. Resting energy expenditure (REE) will be measured using indirect calorimetry at 
baseline (month 0) and month 6.  
 
Background and Significance 
 
Annually 1.5 million children and adults experience trauma to the head and brain that results in a 
traumatic brain injury (TBI). While TBI are classified as severe, moderate, or mild based upon the 
Glasgow Coma Scale (GCS), of the more than 1.5 million people who experience a TBI each 
year, as many as 90% sustain a mild TBI (mTBI) (1). mTBI can occur during organized sport 
(football, soccer), home recreation (bike riding, skateboarding), and as a result of a motor vehicle 
accident or other physical traumatic event. The term ‘mild TBI’ is misleading as we now know that 
a significant proportion of mTBI patients suffer from significant impairments or disabilities for many 
years following the initial brain injury. These include, “foggy brain,” short-term memory loss, (1) 
impaired conversational abilities, and inability to organize daily activities.  Together, this symptom 
complex renders many individuals unable to function in school or maintain a job. 
 
Our research team has found evidence to suggest that TBI induces a chronic inflammatory 
process that renders a subset of the patients with pituitary dysfunction and abnormal GH secretion 
along with other metabolic abnormalities (impaired GI microbiome, impaired nutrient absorption). 
The clinical syndrome, which we have named Brain Injury Associated Fatigue and Altered 
Cognition (BIAFAC), associated with abnormal GH secretion is characterized by profound 
fatigue and cognitive dysfunction related to executive function, short-term memory, and 
processing speed index. Fatigue in abnormal GH secretion patients is profound and debilitating, 
results in increased sleepiness, with disturbed sleep. These patients are no longer able to 
maintain their usual activity levels and other hormone replacements such as testosterone do not 
improve their condition. While we and others are working to classify this clinical syndrome, the 
metabolic implications of TBI as a chronic inflammatory disease are unknown and need classifying 
to describe the syndrome complex. 
 
Remarkably, our examination of the GI microbiome in patients with chronic TBI revealed 
significant differences in selected bacteria (both presence/absence as well as altered relative 
abundance in the community) suggesting a mechanism by which the gut/brain axis was impacted 
leading to the fatigue and cognitive dysfunction syndrome.  Further, these altered bacterial 

 
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communities were associated with changes in amino acid absorption as indicated by blood levels 
in chronic TBI patients.  These recent and exciting data suggest that TBI and its symptom complex 
persist for many years and with far-reaching metabolic health implications. Together, these data 
also suggest similar alterations in the GI microbiome in mTBI patients would be observed 
providing opportunities for both diagnostic and therapeutic improvements.   
 
Our recent work has shown that cognitive and physical dysfunction are significantly improved with 
recombinant human growth hormone (rhGH) replacement in patients with abnormal GH secretion. 
The mechanisms causing fatigue and cognitive dysfunction need to be determined, but our brain 
imaging from functional MRI (fMRI) data suggests that brain connectivity is impaired in patients 
and rhGH may improve connectivity. In chronic TBI patients who have received rhGH treatments, 
it is not yet established if the GI microbiome is returned to a healthy profile observed in control 
cohorts.  Our overall hypothesis is that baseline GI microbiome in mTBI will be significantly altered 
compared to household controls, and that rhGH therapy may result in symptom resolution in mTBI 
which may correlate with the change in GI microbiome. 
 
Post-acute COVID Syndrome Complex (PASC) 
 
The onset of the COVID-19 pandemic has led to a subset of patients that, once recovered from 
the acute infection, also experience an intractable and debilitating set of lingering symptoms 
termed post-COVID syndrome (PASC). The most common symptoms include anxiety, shortness 
of breath, continued loss of the sense of smell and taste, loss of appetite with subsequent weight 
loss, sleep difficulties, severe fatigue, cognitive dysfunction (foggy brain) and increased frailty. 
These patients frequently present to the emergency room looking for symptom management 
because they are unable to perform normal activities of daily living and maintain job performance. 
The mechanisms behind this syndrome have proven elusive because patients varied in symptom 
severity and treatment regimen including different requirements for hospitalization, supplemental 
oxygen, dexamethasone and remdesivir.  
Persistent and long-lasting health problems are common in patients after COVID-19 
infection. In a recent study of patients that had been hospitalized with COVID-19, two months 
after discharge, 87% reported at least one lingering symptom (joint pain, fatigue, breathing issues, 
etc), more than 50% reported more than three lingering issues, and over 40% reported a reduction 
in their of quality of life. Another study found that at 1-month after hospitalization for COVID-19, 
74% reported persistent issues related to shortness of breath and a decrease in both physical 
and mental health. Preliminary data from our Post-COVID Recovery clinic agree with these two 
recent reports.  In our study, 1 1/2 months after COVID-19 diagnosis, patients reported on 
average 10 of the 18 common symptoms (with 90% having chest pain, 87% dyspnea, 75% fatigue, 
and 90% with cognitive changes). While the previous studies examined patients that had severe 
COVID-19 infections, >50% of our patients were never hospitalized, yet have numerous persistent 
symptoms. This has serious implications for the ability of patients to return to work, downstream 
effects on mental health due to sometimes drastic lifestyle and work capacity changes, and the 
ability to engage in activities or hobbies enjoyed prior to COVID-19 illness. In a current study we 
aimed to characterize the baseline endocrine, metabolic, inflammatory and microbiome 
alterations in the post-COVID syndrome patients to better identify and manage the symptoms to 

 
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prevent potential long-term health consequences.  Two post-COVID subjects have been studied 
and both subjects had low levels of growth hormone secretion, consistent with BIAFAC subjects. 
Fecal microbiome analysis of the subjects using the BIAFAC 96 well qPCR array showed striking 
similarity to BIAFAC subjects showing low abundance of Prevotella spp and an absence of P. 
copri.  
 
 
Therapeutic Rationale  
 
As described above, our research team has developed a novel therapeutic strategy using rhGH 
that we have shown to be efficacious at improving fatigue, skeletal muscle function, cognitive 
function, and now appears to be positively impacting the connection between different brain 
regions as measured with fMRI. 
 
Growth hormone as a therapeutic strategy to improve the clinical syndrome and symptom 
complex in mTBI. The rationale behind treating mTBI and fatigue with rhGH is based upon the 
data that shows that individuals with a history of TBI exhibit evidence of growth hormone (GH) 
deficiency (2-6), including those military personnel with blast-related mTBI (2).  This deficiency 
may be related to perceptual fatigue (2, 4-6), although not all studies show a significant 
relationship (7, 8). Our recently completed study will be the first that investigated, and 
demonstrated, the efficacy of rhGH replacement for the reduction of perceptual fatigue in mTBI 
patients with GH deficiency or insufficiency. Moreover, our previous data in moderate to severe 
GH-deficient TBI patients showed an improvement in cognitive function including processing 
speed index, short-term memory, and executive function (9), and our recently study in mTBI 
appears to improve cognition as well.  
 
The gut-brain axis is disrupted in TBI patients, promoting alterations in the gut 
microbiome. There is a rapidly expanding field of study assessing the interaction between the 
immune system and the brain (10).  One of the primary interests in this field of study is the 
interaction between the brain and the GI system centered on the microbiome present in the GI 
track (11, 12).  Consistent with our ongoing hypothesis, a chronic inflammatory process in the 
brain could alter gut physiology and the GI microbiome in subjects with TBI resulting in abnormal 
amino acid absorption. Furthermore, mTBI is associated with alterations in GI metabolism and 
loss of tight junctions contributing to increased intestinal permeability, inflammation, and 
malabsorption (13, 14). In addition to contributing to chronic inflammation, disruption of the 
autonomic nervous following neurotrauma in mTBI patients can disrupt physiology of organs 
throughout the body including intestinal contractility (15-17). Reductions in gut mobility in turn 
disturbs the existing balance of the microflora and promotes small intestinal bacterial overgrowth 
contributing to dysbiosis (18). Regardless of the underlying mechanisms driving alterations in the 
gut-brain-microbiota axis, it is yet unknown how microflora of mTBI patients compared to that of 
healthy individuals. 
Growth hormone as a therapeutic strategy to improve the clinical syndrome and symptom 
complex in PASC. 
 

 
5
Notably, the cluster of symptoms associated with post-COVID syndrome include profound fatigue 
and cognitive dysfunction, which are strikingly consistent with BIAFAC. While studies are 
underway to understand the details of the mechanism causing BIAFAC and why GH treatment 
alleviates symptoms in these patients, we are intrigued that the symptom phenotype with post-
COVID patients overlaps with many BIAFAC symptoms. It is possible that post-COVID syndrome 
may be addressed through similar treatment strategies including the potential for 
prebiotic/probiotic enhancement of microbiome health. 
 
Therefore, in the current study we will assess the GI microbiota in individuals with a history of 
mTBI or PASC and fatigue. Each participant’s baseline will serve as an individual control. An 
additional and critical control dataset that will be used for comparisons will be provided by analysis 
of the GI microbiome from healthy controls. Furthermore, we will investigate whether treatment 
with recombinant Human Growth Hormone (rhGH) will create changes in the gut flora producing 
microbiomes more similar to those expected in healthy controls and whether these changes 
correlate with the expected improvements in fatigue, cognition, brain activation, and brain 
morphology in the mTBI or PASC patients. 
 
 
Experimental Design and Methods 
 
 
Enrollment 
 
TBI subjects: To address AIM 1a and AIM 1b we will study subjects with a history of mild TBI 
enrolled into either arm 1 (n=25) or arm 2 (n=25) for a total of (n=50).  
 
Healthy Controls: To address AIM 1 and AIM 3 we will study healthy control subjects enrolled 
into either arm 1 (n=25) or arm 2 (n=25) for a total of (n=50).  
 
PASC subjects: To address AIM 3 we will study subjects with a history of COVID-19 and PASC 
symptoms enrolled into arm 3 (n=25).  
 
 
 
 
 
ARM 1: mTBI and Household Controls 
Subjects. We will study subjects (aged 18-70 years) with a history of mild TBI (n=25) and their 
household controls (aged 18 years and up) (n=25). mTBI subjects will undergo a 6-month 
intervention of rhGH therapy (See Figure 1). Household controls will be asked to participate in 
questionnaires, blood draws (amino acid analysis), and fecal sampling (GI microbiome analysis). 
Household controls will not receive any growth hormone treatment.  
 
 
 
 

 
6
 
 
 
 
 
mTBI group 
All patients presenting with a prior mTBI will undergo a phone pre-screen including the Brief 
Fatigue Inventory (BFI) questions 1-3. If they score ≥ 3 on any BFI questions 1-3, and are 
interested in participating in the study, they will be scheduled for a formal consenting and medical 
screening at the UTMB Clinical Research 
Center 
(CRC). 
During 
the 
medical 
screening, eligibility will be confirmed and a 
glucagon stimulation test (GST) will be 
performed. A glucagon stimulation with a 
growth hormone peak of <10 ng/mL is 
required to qualify for enrollment. This is the 
range we have used in our previous studies 
to be inclusive of all subjects who have a 
less than normal (>10 ng/mL) response to 
GST. In our previous studies, patients with 
a response to the GST in the 3 – 10 ng/mL 
range have benefited from GH therapy as 
much as those with a less than 3 ng/mL 
response.  
 
 
Household control group 
 
All household controls will undergo a phone 
pre-screen and if interested in participating 
in the study, will be scheduled for a formal 
consenting and medical screening at the 
UTMB Clinical Research Center (CRC). 
 
 
 
ARM 2: mTBI and Healthy Matched 
Controls 
 
Subjects. We will study subjects (aged 18-
70 years) with a history of mild TBI (n=25) 
and healthy age/sex matched controls 
(aged 18-70 years) (n=25). mTBI subjects 
will undergo a 6-month intervention of rhGH 
therapy (See Figure 2). Healthy matched 
controls will be asked to participate in 
questionnaires, blood draws (amino acid 
analysis), 
and 
fecal 
sampling 
(GI 
microbiome analysis). Healthy controls will 
not receive any growth hormone treatment.  
 

 
7
mTBI group 
All patients presenting with a prior mTBI will undergo a phone pre-screen including the Brief 
Fatigue Inventory (BFI) questions 1-3. If they score ≥ 3 on any BFI questions 1-3, and are 
interested in participating in the study, they will be scheduled for a formal consenting and medical 
screening at the UTMB Clinical Research Center 
(CRC). During the medical screening, eligibility will 
be confirmed and a glucagon stimulation test (GST) 
will be performed. A glucagon stimulation with a 
growth hormone peak of <10 ng/mL is required to 
qualify for enrollment. This is the range we have 
used in our previous studies to be inclusive of all 
subjects who have a less than normal (>10 ng/mL) 
response to GST. In our previous studies, patients 
with a response to the GST in the 3 – 10 ng/mL 
range have benefited from GH therapy as much as 
those with a less than 3 ng/mL response.  
 
 
Healthy control group 
 
Healthy controls will undergo a phone pre-screen 
and if interested in participating in the study, will be 
scheduled for a formal consenting and medical 
screening at the UTMB Clinical Research Center 
(CRC). 
 
 
 
 
 
 
 
 
 
ARM 3: PASC 
 
Subjects. We will study subjects (ages 18 - 70 years) with a history of COVID (n=25). PASC 
subjects will undergo a 9-month intervention of rhGH therapy (See Figure 3).  
 
PASC group 
All patients presenting with PASC will undergo a phone pre-screen including the Brief Fatigue 
Inventory (BFI) questions 1-3. If they score ≥ 3 on any BFI questions 1-3, and are interested in 
participating in the study, they will be scheduled for a formal consenting and medical screening at 
the UTMB Clinical Research Center (CRC). During the medical screening, eligibility will be 
confirmed and a glucagon stimulation test (GST) will be performed. A glucagon stimulation with a 
growth hormone peak of <10 ng/mL is required to qualify for enrollment. This is the range we have 
used in our previous studies to be inclusive of all subjects who have a less than normal (>10 
ng/mL) response to GST. In our previous studies, patients with a response to the GST in the 3 – 
10 ng/mL range have benefited from GH therapy as much as those with a less than 3 ng/mL 

 
8
response. Patients with GST scores higher than 10 ng/ml will not be included in the treatment 
study, but may be asked to collect a single fecal sample (omnigene and viable). 
 
 
See Protection of Human Subjects - Recruitment Methods and 
Consenting Process for detailed information regarding recruitment 
and consenting.  
 
 
Experimental Protocol.  
 
mTBI Group (Arm 1) 
Before and at completion (month 6) of the rhGH intervention, mTBI 
subjects will report to the UTMB Institute for Translational Sciences 
(ITS) Clinical Research Center  (CRC) for testing, which will 
consist of cognitive function assessment (MoCA), determination of 
brain morphology and connectivity using fMRI, determination of 
lean mass and fat mass using DEXA, resting energy expenditure, 
functional testing including leg strength and 6 minute walk test, 
fatigue measurements,  and questionnaires of mood and quality of 
life, gastrointestinal health, sleep, and food preferences. Blood 
sampling for measurement of amino acid levels, hormones, and 
metabolites will be drawn before and 90 minutes (+/- 10 minutes) 
after a standardized meal. In addition, fecal samples for analysis 
of the GI microbiome will be collected monthly for the duration of 
the study. Insulin Growth Factor 1 (IGF-1) levels will monitored at 
a month 1 safety visit for all mTBI subjects. The month 1 safety 
visit will occur +/- 5 days from the expected date based on the 
baseline study visit. The monthly fecal sampling will occur +/- 7 
days from the expected date based on the baseline study visit. The 
month 6 post study will occur +/- 7 days from the expected date 
based on the baseline study visit. A member of the study team will 
contact the subject each month to coordinate fecal sample 
transport to UTMB, check for adverse events and overall well-
being, and ensure compliance and ongoing consent. If a mTBI 
subject sustains and additional TBI during the study, the study for 
both the mTBI and household control subject will be extended to 
collect monthly fecal samples and questionnaires for an additional 
6 months. Genotropin will be provided for the additional 6 months.  
 
Household control group  (Arm 1) 
Before and at completion (month 6) of the rhGH intervention of 
their mTBI subject partners, household controls will report to the 
UTMB Institute for Translational Sciences (ITS) Clinical Research 
Center (CRC) for testing, which will consist of questionnaires of 
food preferences and gastrointestinal health and blood sampling 
for measurement of amino acid levels, hormones, and metabolites 
which will be drawn before and 90 minutes (+/ 10 minutes) after a standardized meal. In addition, 
fecal samples for the analysis of the GI microbiome will be collected monthly for the duration of 
the study, as well as questionnaire assessing gastrointestinal health. The monthly fecal sampling 

 
9
will occur +/- 7 days from the expected date based on the baseline study visit. The post study 
(month 6) will occur +/- 7 days from the expected date based on the baseline study visit. A member 
of the study team will contact the subject each month to coordinate fecal sample transport to 
UTMB, check for adverse events and overall well-being, and ensure compliance and ongoing 
consent.  If the mTBI subject sustains and additional TBI during the study, the study for both the 
mTBI and household control subject will be extended to collect monthly fecal samples and 
questionnaires for an additional 6 months. 
 
mTBI Group (Arm 2) 
Before and at completion (month 6) of the rhGH intervention, mTBI subjects will report to the 
UTMB Institute for Translational Sciences (ITS) Clinical Research Center  (CRC) for testing, which 
will consist of cognitive function assessment (MoCA), determination of lean mass and fat mass 
using DEXA, resting energy expenditure, functional testing including leg strength and 6 minute 
walk test, fatigue measurements,  and questionnaires of mood and quality of life, gastrointestinal 
health, sleep, and food preferences. Blood sampling for measurement of amino acid levels, 
hormones, and metabolites will be drawn before and 90 minutes (+/- 10 minutes) after a 
standardized meal. In addition, fecal samples for analysis of the GI microbiome will be collected 
monthly for the duration of the study. Insulin Growth Factor 1 (IGF-1) levels will monitored at a 
month 1 safety visit for all mTBI subjects. The month 1 safety visit will occur +/- 5 days from the 
expected date based on the baseline study visit. The monthly fecal sampling will occur +/- 7 days 
from the expected date based on the baseline study visit. The month 6 post study will occur +/- 7 
days from the expected date based on the baseline study visit. A member of the study team will 
contact the subject each month to coordinate fecal sample transport to UTMB, check for adverse 
events and overall well-being, and ensure compliance and ongoing consent. If the mTBI subject 
sustains and additional TBI during the study, the study will be extended to collect monthly fecal 
samples and questionnaires for an additional 6 months. Genotropin will be provided for the 
additional 6 months.  
 
Healthy control group (Arm 2) 
Healthy control subjects will report to the UTMB Institute for Translational Sciences (ITS) Clinical 
Research Center (CRC) for testing at baseline and month 6. Testing will consist of questionnaires 
of food preferences and gastrointestinal health and blood sampling for measurement of amino 
acid levels, hormones, and metabolites which will be drawn before and 90 minutes (+/ 10 minutes) 
after a standardized meal. In addition, fecal samples for the analysis of the GI microbiome will be 
collected monthly for the duration of the study, as well as questionnaire assessing gastrointestinal 
health. The monthly fecal sampling will occur +/- 7 days from the expected date based on the 
baseline study visit. The post study (month 6) will occur +/- 7 days from the expected date based 
on the baseline study visit. A member of the study team will contact the subject each month to 
coordinate fecal sample transport to UTMB, check for adverse events and overall well-being, and 
ensure compliance and ongoing consent.   
 
PASC Group (Arm 3) 
PASC subjects will undergo 9 months of rhGH treatment. Before and at (month 6) of the rhGH 
intervention, PASC subjects will report to the UTMB Institute for Translational Sciences (ITS) 
Clinical Research Center  (CRC) for testing, which will consist of cognitive function assessment 
(MoCA), determination of lean mass and fat mass using DEXA, resting energy expenditure, 
functional testing including leg strength and 6 minute walk test, fatigue measurements,  and 
questionnaires of mood and quality of life, gastrointestinal health, sleep, and food preferences. 
Blood sampling for measurement of amino acid levels, hormones, and metabolites will be drawn 
before and 90 minutes (+/- 10 minutes) after a standardized meal. In addition, fecal samples for 

 
10 
analysis of the GI microbiome will be collected monthly for the duration of the study. Insulin Growth 
Factor 1 (IGF-1) levels will monitored at a month 1 safety visit for all PASC subjects. The month 
1 safety visit will occur +/- 5 days from the expected date based on the baseline study visit. The  
fecal sampling will occur +/- 7 days from the expected date based on the baseline study visit at 
months 0, 1, 2, 3, 4, 5, 6, 9 and 12. The month 6 study will occur +/- 7 days from the expected 
date based on the baseline study visit.  The month 9 study will consist of fecal sample and 
questionnaires only. At month 12, the subject will return to the ITS-CRC to repeat the glucagon 
stimulation test (GST).  Questionnaires and a fecal sample will also be collected at this time. A 
member of the study team will contact the subject each month to coordinate fecal sample transport 
to UTMB, check for adverse events and overall well-being, and ensure compliance and ongoing 
consent. If a PASC subject is infected with COVID again during the study months 9 - 12, the study 
will be extended to collect fecal samples and questionnaires for an additional 3 months.  
 
 
Therapeutic Intervention (for mTBI subjects only - Arms 1&2; PASC subjects – Arm 3).  
Recombinant human growth hormone (rhGH), (GENOTROPIN). Growth hormone (GH) is 
produced endogenously by the body and is released by the pituitary. Therapeutic rhGH is FDA 
approved for clinical use for replacement of endogenous growth hormone in children and adults 
with growth hormone deficiency. GENOTROPIN, the agent to be used in this study is 
manufactured by Pfizer Inc and contains somatropin, which is a polypeptide hormone of 
recombinant DNA origin. It contains 191 amino acid residues and is identical to human growth 
hormone of pituitary origin.  
 
GENOTROPIN (5 mg) is dispensed in a two-chamber cartridge. The front chamber contains 
recombinant somatropin (5.8 mg), glycine (2.2 mg), mannitol (1.8 mg), sodium dihydrogen 
phosphate anhydrous (0.32 mg), and disodium phosphate anhydrous (0.31 mg); the rear chamber 
contains 0.3% m-Cresol (as a preservative) and mannitol (45 mg) in 1.14 mL water for injection. 
The reconstituted concentration is 5 mg/ml. GENOTROPIN will be administered utilizing the 
GENOTROPIN Pen 5 (manufactured by Pfizer, Inc). The GENOTROPIN Pen 5 is a reusable 
multi-dose pen that the two-chambered cartridge is inserted into. Once the cartridge is inserted 
into the pen, the two-chambers are mixed.  A 31 gauge, ½ inch needle is attached to the pen for 
administration. The pen can then be dialed on the digital display to the correct dose and 
administered by the user. The needle is then carefully removed and disposed in a sharps medical 
waste container provided by the study team. Once the cartridge is empty, a new cartridge can be 
inserted into the pen, a 5 mg cartridge will last 1 – 2 weeks depending on the dose used. The 
GENOTROPIN Pen 5 is designed to be easily used, as most GH replacement is for pediatric use. 
Subjects will undergo a familiarization session with the study team to learn how to load the 
GENOTROPIN5 cartridges into the GENOTROPIN Pen 5 device, how to dial their dose, and how 
to administer injections. They will also be given a guide and the web address 
(http://www.genotropin.com/genotropin-helpful-tools) of a video prepared by the makers of 
GENOTROPIN to take home for reference.  
 
In this study, single injections containing 0.4 mg of GENOTROPIN will be administered to mTBI 
and PASC subjects on a daily basis until the IGF-1 safety check at month 1. If the IGF-1 value is 
less than 400 ng/mL, the subject will be directed to increase the dose to 0.6 mg per day for the 
remainder of the study. 0.6 mg per day is the standard dose given in our TBI research studies. 
We have treated approximately 60 TBI research subjects over approximately 14 years at this dose 
without incident. Dr. Urban also has approximately 100 patients in his clinic being treated at 0.6 

 
11 
mg per day. At this dose of GH replacement, there is no evidence of insulin resistance and as 
long as the IGF-1 remains at or below 400 ng/mL, there is minimal risk of carpal tunnel syndrome. 
GENOTROPIN and the GENOTROPIN Pen 5 will be supplied by Pfizer, with allocation managed 
by the Investigational Drug Service (IDS) of the UTMB Department of Pharmacy.  Any unused 
drug will be disposed of by the IDS of the UTMB Department of Pharmacy according to standard 
drug destruction procedures. If a missed dose is identified on the day it is to be given, the subject 
will be instructed to inject the normal daily dose as soon as possible. For example, the subject 
usually gives their injection in the morning, but forgets and then remembers in the afternoon.  If a 
missed dose is identified after the normal dosing day, the subject will be instructed to count that 
day as a missed day and resume their normal dosing schedule. For example, the subject 
remembers on Tuesday that they missed their dose on Monday. Subjects will be instructed not to 
take more than one dose a day.  
Screening Procedures for mTBI subjects:  All mTBI subjects consenting to be screened will 
undergo the following procedures. mTBI subjects will be fasted for at least 10 hours prior to blood 
work. Screenings will take place at the UTMB Clinical Research Center (CRC).  Differences in 
procedures between Arm 1 and Arm 2 will be noted. 
 
• Vital signs. Vital signs will be collected at screening. This will include height, weight, blood 
pressure, pulse, respirations, and temperature. Vital signs will be recorded on the screening CRF.  
 
• Urine Pregnancy Test. Urine will be collected from female subjects for a urine pregnancy test to 
be performed at the UTMB CRC as POCT. Women who are post-menopausal will be exempt from 
this test. 
 
• Phlebotomy.  mTBI subjects will have a catheter placed into a peripheral vein in their arm (0.9% 
sodium chloride set at TKO) for the glucagon stimulation test and the screening labs. The IV will 
be discontinued when glucagon stimulation test is complete.  
 
• Electrocardiogram (EKG). mTBI subjects will have an EKG during screening. The EKG will take 
place at the CRC, performed by UTMB Cardiology staff and read by UTMB Cardiology Faculty, 
and will be entered into the subjects UTMB medical chart.  
 
• Screening Blood Labs.  mTBI subjects will have the following labs drawn for screening. 
Approximately 20 ml of blood will be drawn for screening labs listed below. The labs will be sent 
to the UTMB clinical laboratory for analysis and entered into the subjects UTMB medical chart:  
 
- 
Complete blood count with differential (CBC w/ diff) 
- 
Comprehensive metabolic panel (CMP) 
- 
Lipid Panel 
- 
Hepatitis B surface antigen 
- 
Hepatitis C virus antibody 
- 
HIV screen 
- 
Thyroid-stimulating hormone (TSH) 
- 
Prolactin 
- 
Testosterone Total (men only) 

 
12 
- 
Insulin-like Growth Factor 1 (IGF-1) 
- 
Cortisol  
 
• Glucagon stimulation test.  mTBI subjects will have a glucagon stimulation test. After the IV is 
placed, 3.5 ml of blood will be collected for the baseline (time: 0 minutes) to test for levels of 
human growth hormone. 1 mg glucagon (for subjects over 90 kg, 1.5 mg glucagon) will be injected 
IM in the deltoid muscle of the subject. Additional blood samples (3.5 mL) will be collected to test 
for levels of human growth hormone at time points: 90 minutes, 120 minutes, 150 minutes, and 
180 minutes. All blood samples will be sent to UTMB clinical laboratory for analysis and entered 
into subjects UTMB medical chart.   
 
• History and Physical.  mTBI subjects will undergo a medical history and physical examination by 
a study nurse or physician.  
 
Screening Procedures for PASC subjects:  All PASC subjects consenting to be screened will 
undergo the following procedures. Subjects will be fasted for at least 10 hours prior to blood work. 
Screenings will take place at the UTMB Clinical Research Center (CRC).  
 
• Vital signs. Vital signs will be collected at screening. This will include height, weight, blood 
pressure, pulse, respirations, and temperature. Vital signs will be recorded on the screening CRF.  
 
• Urine Pregnancy Test. Urine will be collected from female subjects for a urine pregnancy test to 
be performed at the UTMB CRC as POCT. Women who are post-menopausal will be exempt from 
this test. 
 
• Phlebotomy.  Subjects will have a catheter placed into a peripheral vein in their arm (0.9% sodium 
chloride set at TKO) for the glucagon stimulation test and the screening labs. The IV will be 
discontinued when glucagon stimulation test is complete. This may be omitted if subject has 
recent (within 6 months) glucagon stimulation test on file.  
 
• Electrocardiogram (EKG). Subjects will have an EKG during screening. The EKG will take place 
at the CRC, performed by UTMB Cardiology staff and read by UTMB Cardiology Faculty, and will 
be entered into the subjects UTMB medical chart.  
 
• Screening Blood Labs.  Subjects will have the following labs drawn for screening. Approximately 
20 ml of blood will be drawn for screening labs listed below. The labs will be sent to the UTMB 
clinical laboratory for analysis and entered into the subjects UTMB medical chart. Labs may be 
omitted if subject has recent (within 6 months) labs on file.   
 
- 
Complete blood count with differential (CBC w/ diff) 
- 
Comprehensive metabolic panel (CMP) 
- 
Lipid Panel 
- 
Hepatitis B surface antigen 
- 
Hepatitis C virus antibody 
- 
HIV screen 
- 
Thyroid-stimulating hormone (TSH) 
- 
Prolactin 
- 
Testosterone Total (men only) 
- 
Insulin-like Growth Factor 1 (IGF-1) 

 
13 
- 
Cortisol  
 
• Glucagon stimulation test.  Subjects will have a glucagon stimulation test. After the IV is placed, 
3.5 ml of blood will be collected for the baseline (time: 0 minutes) to test for levels of human growth 
hormone. 1 mg glucagon (for subjects over 90 kg, 1.5 mg glucagon) will be injected IM in the 
deltoid muscle of the subject. Additional blood samples (3.5 mL) will be collected to test for levels 
of human growth hormone at time points: 90 minutes, 120 minutes, 150 minutes, and 180 minutes. 
All blood samples will be sent to UTMB clinical laboratory for analysis and entered into subjects 
UTMB medical chart.  GST may be omitted if subject has recent (within 6 months) GST on file.  
 
• History and Physical.  Subjects will undergo a medical history and physical examination by a study 
nurse or physician. Recent (within 3 months) clinical history and physical may be used in place.  
 
 
Screening procedures for household controls (Arm 1) and healthy controls (Arm 2):  All 
control subjects consenting to be screened will undergo the following procedures. Subjects will 
be fasted for at least 10 hours prior to blood work. Screenings will take place at the UTMB Clinical 
Research Center (CRC). 
 
• Vital signs. Vital signs will be collected at screening. This will include height, weight, blood 
pressure, pulse, respirations, and temperature. Vital signs will be recorded on the screening CRF.  
 
• Urine Pregnancy Test. Urine will be collected from female subjects for a urine pregnancy test to 
be performed at the UTMB CRC as POCT. Women who are post-menopausal will be exempt from 
this test.  
 
• Phlebotomy.  Household control subjects will have blood taken using a 21-gauge butterfly needle.  
 
 
• Screening Blood Labs.  Household controls will have the following labs drawn for screening. 
Approximately 20 ml of blood will be taken for screening labs listed below. The labs will be sent 
to the UTMB clinical laboratory for analysis and will be entered into subjects UTMB medical chart:  
 
- 
Complete blood count with differential (CBC w/ diff) 
- 
Comprehensive metabolic panel (CMP) 
- 
Lipid Panel 
- 
Thyroid-stimulating hormone (TSH) 
- 
Hepatitis B surface antigen 
- 
Hepatitis C virus antibody 
- 
HIV screen 
 
• History and Physical.  Household control subjects will undergo a medical history and physical 
examination by a study nurse or physician. 
 
Study Procedures for mTBI subjects (Arm 1 & 2) / PASC subjects (Arm 3): 
 
mTBI and PASC subjects will complete all procedures listed below. Differences in procedures 
between Arm 1, Arm 2 and Arm 3 will be noted. 
 

 
14 
 
• Vital signs. Vital signs will be collected at all study visits. This will include height, weight, blood 
pressure, pulse, respirations, and temperature. Vital signs will be recorded on the appropriate 
study visit CRF.  
 
• Blood draw. Subjects will have blood drawn at the baseline (month 0), safety check (month 1),  
post-study (month 6) and final study (month 12 – Arm 3 PASC only) visits. Blood will be drawn 
using a butterfly needle from a peripheral vein in the arm.  
 
- Baseline Visit (Month 0):  
Up to 15 ml of blood (1-serum separator top (5ml); 1-lithium heparin (6ml); 1-K-EDTA (4ml)) 
will be collected from fasted (at least 10 hours) subjects for analysis of hormones, amino 
acids and metabolites. In addition, up to 13ml of blood (1-serum separator top (5ml); 1-
lithium heparin (6ml)) will be collected after a standardized meal for the analysis of amino 
acids.  
 
- 
Safety Check Visit (Month 1): 
Approximately 3.5 ml of blood for Insulin-like growth factor 1 (IGF-1) will be collected. Blood 
will be sent to UTMB clinical laboratory for analysis and documented in the subject’s UTMB 
medical chart. 
 
- 
Post Visit (Month 6): 
Up to 15 ml of blood (1-serum separator top (5ml); 1-lithium heparin (6ml); 1-K-EDTA (4ml)) 
will be collected from fasted (at least 10 hours) subjects for analysis of hormones, amino 
acids and metabolites. In addition, up to 13ml of blood (1-serum separator top (5ml); 1-
lithium heparin (6ml)) will be collected after a standardized meal for the analysis of amino 
acids.  
 
An additional 20 ml of blood will be collected for the following labs to be sent to the UTMB 
clinical laboratory for analysis (all labs run at UTMB will be documented in the subject’s 
UTMB medical chart): 
• Complete blood count with differential (CBC w/ diff) 
• Comprehensive metabolic panel (CMP) 
• Lipid Panel 
• Insulin-like Growth Factor 1 (IGF-1) 
 
- 
Final Visit (Month 12) – Arm 3 PASC only: 
Up to 15 ml of blood (1-serum separator top (5ml); 1-lithium heparin (6ml); 1-K-EDTA (4ml)) 
will be collected from fasted (at least 10 hours) subjects for analysis of hormones, amino 
acids and metabolites.  
 
An additional 20 ml of blood will be collected for the following labs to be sent to the UTMB 
clinical laboratory for analysis (all labs run at UTMB will be documented in the subject’s 
UTMB medical chart): 
• Complete blood count with differential (CBC w/ diff) 
• Comprehensive metabolic panel (CMP) 
• Lipid Panel 
• Insulin-like Growth Factor 1 (IGF-1) 
 

 
15 
 
• Urine Pregnancy Test. Urine will be collected from female subjects for a urine pregnancy test prior 
to DEXA scan. Urine pregnancy test will be performed at the UTMB CRC as POCT. Women who 
are post-menopausal will be exempt from this test.  
 
• Body Composition.  Lean body and fat mass will be measured using DEXA (GE iDEXA) in 
conjunction with published equations (Wang, 1999).  The whole-body scan will be divided into the 
following sub-regions: truncal area, head, right and left arm, and right and left leg. DEXA will be 
measured at baseline (month 0) and post (month 6).  
 
• Indirect calorimetry for Resting Energy Expenditure (REE).  Expired gases will be collected and 
analyzed for O2 and CO2 concentrations for the determination of energy expenditure and substrate 
oxidation (19) in mTBI patients using the ITS-CRC indirect calorimetry system, Vmax Encore, 
Carefusion. The subject will be asked to lie down on a bed and the ventilated canopy hood will be 
placed over their head and shoulders. The room will be darkened and external noises will be 
eliminated, as much as possible. The subject will be asked to relax and remain awake but as still as 
possible for the testing period of 30 minutes. REE will be measured at baseline (month 0) and post 
(month 6).  
 
• Amino Acid Levels.  Circulating blood amino acid levels will be measured before (fasting) and 90 
minutes (+/- 10 minutes) after a standardized meal. Amino acids in response to a meal will be 
measured at baseline (month 0) and post (month 6).  
 
• Functional MRI (fMRI) – Arm 1 only. Functional MRI will be assessed at UTMB’s Radiology and 
analyzed as in previous studies. mTBI patients will be asked to arrive fasting (at least 10 hours) 
for the scan and will be directed to remove all metal items from their body. They will also fill out 
the UTMB MRI safety checklist.  Before the scan begins patients will be asked to relax and clear 
their minds as much as possible and to stay awake. The total time at MRI will take approximately 
30 – 45 minutes. 3 scans will be performed. Scans will be read by UTMB Radiology faculty and 
documented in the subject’s UTMB medical chart. fMRI will be measured at baseline (month 0) 
and post (month 6).  
 
Scan 1.  Structural MRI scan. High-resolution anatomical images covering the whole brain 
including the cerebellum will be acquired using a T1-weighted gradient-echo pulse 
sequence with the following parameters: 3D T1 axial overlay (TR=8.9 ms, TE=1.8 ms, flip 
angle=15°, FOV=260 x 260 mm, slice thickness=1.4 mm, 124 slices; matrix=256 × 160). 
 
Scan 2.   “Resting state” functional MRI scan. FMRI data will be collected using a single-
shot gradient-echo (GRE) reverse spiral pulse sequence [128] to acquire 240 T2* - 
weighted BOLD images (TR = 2 s, TE = 30 ms, flip angle =90°, FOV = 220 x 220 mm, 
voxel size = 3.4 x 3.4 x 3.2 mm, 40 axial slices). Participants will be instructed to keep their 
eyes closed but to remain awake and to not think about anything in particular. A pressure 
belt will be used to record the respiratory signal and a pulse oximeter will be placed on the 
participant’s finger to record the cardiac signal, both of which will be regressed out prior to 
data analyses.  
 
Scan 3.   Diffusion tensor imaging scan. Diffusion tensor images will be collected using a 
single shot echo planar sequence (39 slices, slice thickness: 3 mm; TE/TR: 82.8 ms/9000 
ms, field of view: 220 mm x 220 mm). Diffusion gradients will be applied in 30 directions 

 
16 
(b = 800 s/mm2) (4 averages). Eight reference images (b = 0 s/mm2) will be acquired [129] 
and averaged. We will calculate the diffusion tensor using the averaged images with b = 0 
and b = 800 s/mm2. 
 
• Cognitive Assessment. Subjects will undergo a cognitive assessment at baseline (month 0) and 
post (month 6).  
 
o Montreal Cognitive Assessment (MoCA). The Montreal Cognitive Assessment (MoCA) (20) 
is a rapid assessment of cognition. The MoCA consists of 9 questions with the following 
subcategories: visuospatial/executive, naming, memory, language, abstraction, delayed 
recall and orientation. The MoCA has been used extensively to detect cognitive impairment 
in many conditions, including head trauma. Version 7.1 will be used at the Month 0 testing 
and Version 7.2 will be used at the Month 6 testing.  
 
GI microbiome. The GI microbiome will be assessed using fecal samples collected at monthly 
time points (baseline (month 0), month 1, month 2, month 3, month 4, month 5, and month 6). 
Additional fecal samples will be collected for Arm 3 PASC subjects at month 9 and month 12. If a 
mTBI subject sustains an additional TBI during the study period, the study will be extended to 
collect fecal samples for an additional 6 months. If a PASC subject is infected with COVID again 
during the study months 9 - 12, the study will be extended to collect an additional sample at month 
13 and month 15. Subjects will provide fecal samples as described below. Fecal samples will be 
collected +/- 7 days from specified time point based on baseline (month 0) study. Subjects will be 
allowed to collect monthly fecal samples at home. Samples will be stored at 4°C until transferred 
to UTMB (on/+ 3 days after collection). Subjects will be given a tutorial on how to properly collect 
the fecal sample. They will be given a handout from the manufacturer of the collection kit with 
step by step instructions. They will also be shown a video of the collection process supplied by 
the kit manufacturer. https://www.youtube.com/watch?v=ytr_hmJdHqM&feature=youtu.be&rel=0 
 
Fecal specimens will be collected using the OMNIgene-Gut® (OMR-200) collection kit from 
DNA genotek (please see product inserts attached as pdf files). To assist in collection, the 
additional toilet accessory will be employed where appropriate (OM-AC1). The manufacturer’s 
instructions will guide sample collection. Briefly, fecal material will be collected by catch on a 
kit-provided tissue or toilet hat that has been wiped with a disinfecting wipe prior to use. The 
study participant’s fecal material will be transferred using the kit included spatula into the 
yellow tube top of a collection tube with the purple cap unscrewed. The tube will then be re-
capped tightly and shaken for a minimum of 30 seconds to mix feces with kit included 
stabilization liquid. Storage recommendations as per manufacturer allow up to 60 days at room 
temperature or up to several months at -20°C or -80°C in the kit provided collection tube. 
Samples will be labeled with the subject’s unique code and stored at 4°C until transported to 
University of Texas Medical Branch (UTMB). Samples will be processed and analyzed by 
qPCR as described below.  
 
Nucleic acids will be extracted from batched fecal specimens using a DNeasy 
PowerMicrobiome kit (2600-50-1, Qiagen). If necessary, samples will be diluted/mixed 1:1 with 
sterile PBS to yield a pipettable liquid slurry. For each sample, 100 µl of the fecal liquid fraction 
will be mixed with 200 µl of kit-provided lysis buffer into a commercially available tube 

 
17 
containing 0.1 mm glass beads (2600-50-BT, Qiagen). Samples will then be heated at 55°C 
for 30 minutes. Subsequently, samples will be homogenized for 5 minutes at 30 Hz using a 
Tissue Lyser instrument (Qiagen). Samples then will be centrifuged at 13,000 x g for 1 minute 
at room temperature. The liquid fraction will then be placed into a sterile microtube along with 
50 µl of IRS solution (2600-50-2, Qiagen) and incubated at 4°C for 5 minutes. The sample will 
then be centrifuged as before and the liquid fraction taken for extraction of DNA using a 
MagnaPure 96 automated nucleic acid extraction platform (Roche).  Purified DNA will be used 
for next-generation sequencing and qPCR analyses to create molecular profiles for each 
microbiome. Residual DNA will be archived at -20°C.  
An additional collection will be performed at month 0 and month 6 to collect viable fecal material. 
Fecal samples will be collected using the spatula included in the OMNIgene-Gut kit used in the 
first collection. Briefly, after the participant will transfer fecal material to the yellow top of the 
collection tube for the first collection, then they will scoop another small amount of fecal material 
with the same spatula and transfer it to a prepared cryogenic freezer tube containing sterile PBS 
(without Ca/Mg) and sterile glycerol. The tube will be closed and shaken for a minimum of 30 
seconds to mix with the stabilization liquid. Samples will be labeled with the subject’s unique code 
and stored at 4°C until transported to University of Texas Medical Branch. Samples will then be 
frozen at -80°C and stored until the molecular analysis is complete. After initial analysis, if the 
sample is considered useful (representative of the average BIAFAC subject), it may be thawed, 
diluted in saline and used either to mix in a mathematical ratio to create a synthetic community or 
to be directly transplanted into germ free mice.  If the sample is considered not useful (not 
representative of the average BIAFAC subject) for fecal microbiome transplant into germ free 
mice, the sample will be destroyed.  
 
 
 
• Nasal Microbiome – Arm 3 only. A nasal swab will be performed by research staff or by the subject 
under direction of the research staff. The sterile calcium alginate swab will be inserted into the left 
nare until resistance is met, rotated 5 times and then moved to the right nare and rotated 5 times. 
The swab will be immediately placed in a tube containing MagNAPure lysis buffer. The shaft of 
the swab will be snapped off and discarded leaving the head of the swab immersed in the lysis 
solution. The tube cap will be tightly secured and the tube will be shaken for a minimum of 5 
seconds to saturate the head of the swab with the lysis buffer releasing the bacterial lysate into 
the fluid. Samples will be stored at -80C for subsequent batch DNA extraction on a MagNAPure96 
followed by microbiome profiling by NGS and/or qPCR. Samples will be labeled with the subject’s 
unique code. This outcome measure will be performed at baseline (month 0) and post (month 6) 
to address anosmia/dysosmia common in PASC subjects and to determine if exogenous GH 
impacts the nasal mucosa/microbiome .  
 
• Performance fatigue.  Skeletal muscle strength and fatigue will be assessed in subjects using 
dynamometry testing of the right knee extensors (using a Biodex Pro 4 dynamometer).  If the right 
knee cannot be tested, the left knee will be utilized for this measurement. This outcome measure 
will be performed at baseline (month 0) and post (moth 6) and will include peak isometric and 
isokinetic (concentric) strength, fatigue index and will be performed as follows: 
 
o Warm up: Isokinetic (con/con/500/300); 30 contractions 

 
18 
o Isometric Strength: fixed 90 degrees; 15 seconds of work, 15 seconds of rest. 1 set of 3 
contractions at maximal effort.  
o Isokinetic Strength: (con/con/120/300); 1 contraction every 5 seconds. 1 set of 3 
contractions at maximal effort.  
o Fatigue Index: Isokinetic (con/con/120/300); 50 contractions at maximal effort.  
 
• Modified 6-minute walk.  Walking performance will be assessed in subjects during 6 minutes of 
walking in long corridor hallways.  This is a standard test of walking performance that has been 
validated in similar studies (21-23). Here, the test will be slightly modified, with subjects asked to 
walk at a 25% perceived effort from minute 0 – 2, at a 50% perceived effort from minute 2 – 4, 
and at a 100% effort (as quickly as they can safely walk without running) from minute 4 -6. 
Distance traveled for each 2-minute category will be recorded. The 6-minute walking test will be 
completed at baseline (month 0) and post (month 6).  
 
 
• Questionnaires.  Questionnaires will be completed to assess perceptual fatigue, mood and quality 
of life, symptoms associated with growth hormone deficiency, sleep, depression, food preferences, 
and gastrointestinal symptoms. Time points for the collection of questionnaires are included in each 
description. 
 
o Perceptual fatigue.  Perceptual fatigue will be assessed using the Brief Fatigue Inventory 
(BFI), a 9-item questionnaire that assesses perceptual fatigue as well as fatigue 
interferences (e.g. interference with enjoyment of life). The scores from all 9 questions can 
be average to calculate a Global Fatigue Score, with a range from 0 to 10, with a higher 
score indicating more fatigue. BFI will be completed at month 0 and month 6 in TBI subjects 
(24). PASC subjects complete the BFI at months 0, 6, 9 and 12. The Multidimensional 
Fatigue Symptom Inventory (MFSI) will also be used to measure perceptual fatigue.  
Fatigue symptoms will be measured using the 30-item Multidimensional Fatigue Symptom 
Inventory – Short Form, a validated measure that yields one overall score of total fatigue 
(range -24-96, with higher scores indicating more fatigue) and five subscales (general, 
physical, emotional, mental, vigor). With the exception of the vigor subscale, higher scores 
indicate greater fatigue. The MFSI will be measured at month 0 and month 6 in TBI 
subjects. PASC subjects complete the MFSI at months 0, 6, 9 and 12.  If a mTBI subject 
sustains an additional TBI during the study period, the study will be extended for an 
additional 6 months.  An additional questionnaire will be collected at the end of the 6 month 
period. If a PASC subject is infected with COVID again during the study months 9 - 12, the 
study will be extended to collect an additional questionnaires at month 13 and month 15. 
 
 
o Mood and Quality of Life.  Psychological symptoms will be measured in mTBI subjects 
using the 65-item Profile of Mood States (POMS) questionnaire, a validated measure that 
yields one overall score of total mood disturbance (range 0-168, with higher scores 
indicating more disturbance in mood) and six subscales (tension-anxiety, depression-
dejection, anger-hostility, vigor-activity, fatigue-inertia, and confusion-bewilderment). With 
the exception of the vigor-activity subscale, higher scores indicate greater mood 
disturbance or distress. POMS will be measured at month 0 and month 6 in TBI subjects. 
PASC subjects complete POMS at months 0, 6, 9 and 12.  If a mTBI subject sustains an 
additional TBI during the study period, the study will be extended for an additional 6 

 
19 
months.  An additional questionnaire will be collected at the end of the 6 month period. . If 
a PASC subject is infected with COVID again during the study months 9 - 12, the study will 
be extended to collect an additional questionnaires at month 13 and month 15. 
 
 
o Growth Hormone Deficiency. Symptoms of growth hormone deficiency will be measured in 
mTBI subjects using the Quality of Life – Assessment of Growth Hormone Deficiency in 
Adults (QoL-AGHDA). This 25-item questionnaire measures specific symptoms associated 
with growth hormone deficiency, with a score range of 0 to 25, with a higher score indicating 
worse symptoms (25). The QoL-ADGHA will be measured at month 0 and month 6 in TBI 
subjects. PASC subjects complete the QoL-AGHDA at months 0, 6, 9 and 12.  If  a mTBI 
subject sustains an additional TBI during the study period, the study will be extended for 
an additional 6 months.  An additional questionnaire will be collected at the end of the 6 
month period. . If a PASC subject is infected with COVID again during the study months 9 
– 12, the study will be extended to collect an additional questionnaires at month 13 and 
month 15. 
 
 
o Sleep Quality.  Pittsburgh Sleep Quality Index (PSQI) is a self-rated questionnaire which 
assesses sleep quality and disturbances over a 1 month-time interval. Minimum Score = 0 
(better); Maximum Score = 21 (worse). Interpretation: Total < 5 associated with good sleep 
quality. Total > 5 associated with poor sleep quality. PSQI will be measured at month 0 and 
month 6  in TBI subjects (26). PASC subjects complete the PSQI at months 0, 6, 9 and 12. 
If a mTBI subject sustains an additional TBI during the study period, the study will be 
extended for an additional 6 months.  An additional questionnaire will be collected at the 
end of the 6 month period. . If a PASC subject is infected with COVID again during the 
study months 9 - 12, the study will be extended to collect an additional questionnaires at 
month 13 and month 15. 
 
 
o The Beck Depression Inventory-II (BDI-II) is one of the most widely used self-report 
inventories to assess depressive symptom severity in adolescent and adult populations 
(clinical and non-clinical). The BDI-II is comprised of 21 individual items reflecting specific 
cognitive, affective, and physical symptoms of depression (27).  Each item includes four 
statements that vary in the description of symptom of severity.  Scores range from 0 to 3, 
with a score of “3” indicating a severe symptoms and a score of “0” indicating an absence 
of concern with that particular aspect of depressive symptomology. The total score is the 
sum of all endorsed statements.  If more than one statement from a given item is chosen 
by the respondent, only the statement of greatest severity is scored.  The maximum total 
score is 63.  The BDI-II Manual designates the following raw score classifications 
depression severity: ≤13 = minimal; 14-19 = mild; 20-28 = moderate; ≥ 29 = severe. The 
BDI will be measured at month 0 and month 6 by TBI subjects. PASC subjects complete 
the BDI-II at months 0, 6, 9 and 12.  If a mTBI subject sustains an additional TBI during the 
study period, the study will be extended for an additional 6 months.  An additional 
questionnaire will be collected at the end of the 6 month period. . If a PASC subject is 
infected with COVID again during the study months 9 – 12, the study will be extended to 
collect an additional questionnaires at month 13 and month 15. 
  
 

 
20 
o Food Preference Questionnaire (FPQ). General food preferences will be assessed using 
a modified questionnaire. The food preference questionnaire requires participants to rate 
their liking of 62 individual foods on a 5-point Likert scale, ranging from “not at all” to “a lot”. 
Participants are instructed to select ‘N/A’ if they are not familiar with - or have no memory 
of - having tried a food item. Food preference scale scores for six food categories 
(Vegetables, Fruit, Meat/Fish, Dairy, Snacks, and Starches) are obtained by summing the 
single food preference item scores within each food category and dividing this sum by the 
number of items on the list. FPQ will be measured at month 0 and month 6 by TBI subjects. 
PASC subjects complete the FPQ at months 0, 6, 9 and 12.  If a mTBI subject sustains an 
additional TBI during the study period, the study will be extended for an additional 6 
months.  An additional questionnaire will be collected at the end of the 6 month period. . If 
a PASC subject is infected with COVID again during the study months 9 - 12, the study will 
be extended to collect an additional questionnaires at month 13 and month 15. 
 
 
o Gastrointestinal Symptom questionnaire. Gastrointestinal symptoms will be monitored 
monthly using the Gastrointestinal Symptom Rating Scale (GSRS). The GSRS is a 15-item 
questionnaire. Each question has a seven-point Likert-type scale where 1 represents 
absence of symptoms and 7 represents very troublesome symptoms. The GSRS will be 
measured each time a fecal collection is completed.  If a mTBI subject sustains an 
additional TBI during the study period, the study will be extended for an additional 6 
months.  The GSRS will be collected monthly during the 6 month extension. . If a PASC 
subject is infected with COVID again during the study months 9 - 12, the study will be 
extended to collect an additional questionnaires at month 13 and month 15. 
 
 
• Recombinant Human Growth Hormone Administration.  mTBI and PASC subjects will be asked 
to inject themselves with growth hormone daily. The starting dose will be 0.4 mg/day beginning 
at the baseline study and will increase to 0.6 mg/day when instructed by the study team. The 
dose increase will happen after the month 1 IGF-1 blood draw and the study team reviews the 
results and instructs the subject to increase their dose to 0.6 mg/day. TBI subjects will administer 
growth hormone for 6 months. PASC subjects will administer growth hormone for 9 months. If a 
mTBI subject sustains an additional TBI during the study period, the study will be extended for 
an additional 6 months.  Genotropin will be provided for the additional 6 months at a dose of 0.6 
mg/day.  
 
• Glucagon stimulation test.  Arm 3 PASC subjects will have a glucagon stimulation test at month 
12. After the IV is placed, 3.5 ml of blood will be collected for the baseline (time: 0 minutes) to test 
for levels of human growth hormone. 1 mg glucagon (for subjects over 90 kg, 1.5 mg glucagon) 
will be injected IM in the deltoid muscle of the subject. Additional blood samples (3.5 mL) will be 
collected to test for levels of human growth hormone at time points: 90 minutes, 120 minutes, 150 
minutes, and 180 minutes. All blood samples will be sent to UTMB clinical laboratory for analysis 
and entered into subjects UTMB medical chart.   
 
 
 
Study Procedures for household and healthy control subjects. 
Household controls will complete the procedures below. Differences in procedures between Arm 
1 and Arm 2 will be noted. 

 
21 
 
• Vital signs. Vital signs will be collected at all study visits. This will include height, weight, blood 
pressure, pulse, respirations, and temperature. Vital signs will be recorded on the appropriate 
study visit CRF.  
 
• Blood draw. Subjects will have blood drawn at the baseline (month 0) and post (month 6) visits. 
Blood will be drawn using a butterfly needle from a peripheral vein in the arm. Subjects will be 
fasted for at least 10 hours. 
 
- 
Baseline Visit (Month 0): 
Up to 15 ml of blood (1 serum separator top (5ml); 1 lithium heparin (6ml); 1 K-EDTA (4ml)) 
will be collected from fasted (at least 10 hours) subjects for analysis of hormones, amino 
acids and metabolites. In addition, up to 13ml of blood (1 serum separator top (5ml); 1 
lithium heparin (6ml)) will be collected after a standardized meal for the analysis of amino 
acids. 
 
- 
Post Visit (Month 6):  
Up to 15 ml of blood (1 serum separator top (5ml); 1 lithium heparin (6ml); 1 K-EDTA (4ml)) 
will be collected from fasted (at least 10 hours) subjects for analysis of hormones, amino 
acids and metabolites. In addition, up to 13ml of blood (1 serum separator top (5ml); 1 
lithium heparin (6ml)) will be collected after a standardized meal for the analysis of amino 
acids. 
An additional 20ml of blood will be collected for the following labs to be sent to the UTMB 
clinical laboratory for analysis (labs sent to UTMB lab will be entered into subjects UTMB 
medical chart): 
• 
Complete blood count with differential (CBC w/ diff) 
• 
Comprehensive metabolic panel (CMP) 
• 
Lipid Panel 
 
• Amino Acid Levels.  Circulating blood amino acid levels will be measured before (fasting) and 90 
minutes (+/-10 minutes) after a standardized meal. Amino acids in response to a meal will be 
measured at month 0 and month 6. 
 
• GI microbiome. The GI microbiome will be assessed using fecal samples collected at monthly 
time points (month 0, month 1, month 2, month 3, month 4, month 5, and month 6). Subjects will 
provide fecal samples as described above (see procedures for mTBI subjects – GI microbiome). 
Fecal samples will be collected +/- 7 days from specified time point based on baseline (month 0) 
study. Subjects will be allowed to collect the fecal samples at home. Samples will be stored at 
4°C until transferred to UTMB (on/+ 3 days after collection). Subjects will be given a tutorial on 
how to properly collect the fecal sample. They will be given a handout from the manufacturer of 
the collection kit with step by step instructions. They will also be shown a video of the collection 
process supplied by the kit manufacturer.   
https://www.youtube.com/watch?v=ytr_hmJdHqM&feature=youtu.be&rel=0 
An additional collection will be performed at month 0 and month 6 to collect viable fecal material. 
Fecal samples will be collected using the spatula included in the OMNIgene-Gut kit used in the 
first collection. Briefly, after the participant transfers fecal material to the yellow top of the collection 

 
22 
tube for the first collection, they will scoop another small amount of fecal material with the same 
spatula and transfer it to a prepared cryogenic freezer tube containing sterile PBS (without Ca/Mg) 
and sterile glycerol. The tube will be closed and shaken for a minimum of 30 seconds to mix with 
the stabilization liquid. Samples will be labeled with the subject’s unique code and stored at 4°C 
until transported to University of Texas Medical Branch. Samples will then be frozen at -80°C and 
stored until the molecular analysis is completed. After initial analysis, if the sample is considered 
useful (representative of the average control subject), it may be thawed, diluted in saline and used 
either to mix in a mathematical ratio to create a synthetic community or to be directly transplanted 
into germ free mice.  If the sample is considered not useful (not representative of the average 
control subject) for fecal microbiome transplant into germ free mice, the sample will be destroyed.  
 
 
• Questionnaires.  Questionnaires will be completed to assess general food preferences and 
gastrointestinal symptoms. Time points for the collection of the questionnaires is included in each 
description. 
 
o Food Preference Questionnaire (FPQ). General food preferences will be assessed using 
a modified questionnaire. The food preference questionnaire requires participants to rate 
their liking of 62 individual foods on a 5-point Likert scale, ranging from “not at all” to “a lot”. 
Participants are instructed to select “N/A” if they are not familiar with - or have no memory 
of - having tried a food item. Food preference scale scores for six food categories 
(Vegetables, Fruit, Meat/Fish. Dairy, Snacks, and Starches) are obtained by summing the 
single food preference item scores within each food category and dividing this sum by the 
number of items on the list. FPQ will be measured at month 0 and month 6. 
For Arm 1 only:  If the mTBI subject sustains an additional TBI during the study period, the 
study will be extended for both the mTBI and household control for an additional 6 months.  
An additional questionnaire will be collected at the end of the 6 month period.  
 
 
o Gastrointestinal Symptom questionnaire. Gastrointestinal symptoms will be monitored 
monthly using the Gastrointestinal Symptom Rating Scale (GSRS). The GSRS is a 15-item 
questionnaire. Each question has a seven-point Likert-type scale where 1 represents 
absence of symptoms and 7 represents very troublesome symptoms. The GSRS will be 
measured monthly.  
For Arm 1 only:If the mTBI subject sustains an additional TBI during the study period, the 
study will be extended for both the mTBI and household control for an additional 6 months. 
The GSRS will be collected monthy during the 6 month extension.   
o  
Statistical Considerations  
 
Aim 1a: 
In this protocol we intend to compare the GI microbiome of diagnosed mTBI patients against the 
microbiome of healthy controls (HC). Data will be organized by time (PRE vs. POST) and by 
treatment (mTBI vs. HC). The hypothesis is that group differences between mTBI and HC will 
exist at PRE but that GH treatment in the mTBI group will dissolve these differences at POST.  
 
Power calculations using q-PCR data from 22 diagnosed TBI patients and 15 healthy control 
subjects suggesting that we will be able to detect group differences in genus and/or species in 
the intestinal flora. These calculations suggest that we would need about 6 subjects per group to 
have an 80% probability of detecting significant differences in at least one of the previously 

 
23 
identified organisms (two-sided, a=0.05). With the proposed subject numbers (25 per group) we 
calculate that the power would be between 91 – 100 % for at least 8 of the previously identified 
organisms. 
 
 
Aim 1b: 
Given our recent results from mTBI patients with BIAFAC, that identified two distinct community 
groups, based upon the presence of specific Prevotella species, we require additional participants 
to achieve group sizes of each type to address differences in the individual species for the pre 
and post comparisons. Enrollment: We expect to enroll subjects without the need for a HHC to 
address these differences.  These subjects will be compared to matched normal participants from 
the general population adding 25 TBI and 25 normals to the study creating the power needed to 
address Prevotella positive and negative community types. 
 
Aim 2: 
Given the data acquired from two PASC subjects under IRB 20-0361 that have shown 
indistinguishable profiles to those of BIAFAC communities as well as remarkably reduced GH 
responses to GST, we expect that the Power calculations explained in this section (above) will 
also apply to PASC.  Because PASC is a recent consequence to the pandemic no data exist to 
complete Power calculations beyond those of syndromes like BIAFAC that present with similar 
symptoms. We therefore have proposed enrollment of at least 25 PASC subjects to compare to 
25 normal controls already included in this protocol. 
 
For quantifiable (primary) outcomes such as abundances of individual species in the GI 
microbiome and (secondary) symptom related outcomes, a standard repeated measure ANOVA 
model will be used. When possible, age and other covariates will be brought into the model to 
reduce variability and account for random differences between the two groups.  Significance tests 
will be performed at the alpha=0.05 level, and multiple testing corrections will be used to account 
for potential Type I error rate inflation.  Nonparametric, generalized linear, and transformed 
response models will be considered as necessary to alter the model to account for deviations 
from standard assumptions (normality, linearity, etc.). Current data support statistical outcomes 
being established with group sizes similar or slightly larger size than our previous study.    
 
The graph below is based on group difference in Alistipes onderdonkii. Power calculations were 
performed using t-tests with G*Power (two-groups, two-sided, a=0.05, Version 3.1.9.2, Germany). 
Effect size in this case was 1.184. 
  
Below is a list of organisms we identified previously and which were used to conduct the power 
analyses for the present study. Please note that the intestinal flora includes an incredibly diverse 
system of organisms and at this time it is difficult to accurately predict which organisms will be 
included in the biome shifts we expect to see. Therefore, additional organisms may be included 
in the final microbiome comparisons between mTBI patients and household control subjects. 
Further power analyses will be conducted using the data collected during this investigation.  
 
 

 
24 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Target 
n 
= 
20 
(10/group) 
n=30 
n=40 
n= 
50 
(25/group) 
Alistipes onderdonkii 
70.7% 
87.9% 
95.4% 
98.4% 
Desulfovibrio 
60.4% 
79.3% 
89.9% 
95.4% 
Prevotella spp 
97.5% 
99.8% 
100.0% 
100.0% 
Akkermansia 
64.8% 
83.2% 
92.6% 
96.9% 
Odoribacter 
52.5% 
71.5% 
83.8% 
91.2% 
Ruminococcus 
bicirculans 
57.2% 
76.3% 
87.7% 
93.9% 
Bacteroides vulgatus 
65.6% 
83.9% 
93.1% 
97.2% 
Sutterella 
53.0% 
72.0% 
84.2% 
91.5% 
Lachnoclostridium 
30.8% 
44.4% 
56.4% 
66.4% 
Streptococcus salivarius 
27.8% 
40.2% 
51.4% 
61.2% 
16s 
6.8% 
7.8% 
8.8% 
9.8% 
 
Study Timeline  
Interventional, mechanistic studies such as this one are routinely performed by our research group 
and involve fine coordination between our team and the Clinical Research Center at UTMB.  From 
experience, we know that we will be able to complete ~16 experiments of this type of trial per 
year.  Thus, we anticipate completing all patients at the end of year 3.  Therefore, a 3-year span 
is needed to accomplish all aims, and data analysis and manuscript writing will follow. 
 
 
Protection of Human Subjects 
 
A. Risks to Human Subjects 
 
Human subject involvement and characteristics.  Arm 1: We propose to study a total of 50 patients 
both males and females, with a history of mild TBI (n=25) ages 18 to 70 and their household controls 
(n=25) ages 18 and up. As the mTBI subjects will be selected for study based on their history and 
symptom complex, we expect that screening failures will be low (approximately 20). We also 
expect approximately 4 sets (8 total) of subjects to drop out during the course of the study. Thus, 
in order to achieve a total of 25 pairs (50 individuals) completing the study, we anticipate screening 
and enrolling approximately 78, but up to 100 individuals over 3 years. Arm 2: We propose to study 
a total of 50 patients both male and female consisting of patients with a history of mild TBI (n=25) 
and healthy matched controls (n=25), ages 18-70. As the mTBI subjects will be selected for study 
based on their history and symptom complex, we expect that screening failures will be low. Arm 

 
25 
3: We propose to study a total of 25 patients both male and female consisting of patients with a 
history of COVID-19 ages 18 – 70. As PASC subjects will be selected for the study based on their 
history and symptom complex, we expect that screening failures will be low.  
 
 
ARM 1: 
 
1. mTBI Inclusion criteria Male or female with a diagnosis of mild TBI.  
2. At least 6-month post-injury. 
3. Ages 18 to 70 years. 
4. Lives in same household as paired control that meets inclusion/exclusion criteria. 
5. Participant is willing and able to give informed consent for participation in the study. 
 
mTBI Exclusion criteria  
1. Unable to walk unassisted. 
2. Significant heart, liver, kidney, blood or respiratory disease. 
3. History of chest pain or coronary heart disease. 
4. Uncontrolled Diabetes mellitus.  
5. Any history of a recently (12 months) diagnosed cancer other than a skin cancer (excluding 
melanoma). 
6. Current alcohol or drug abuse. 
7. Premorbid history of psychiatric disorder.  
8. Premorbid history of head trauma. 
9. Pregnancy or become pregnant during the trial. 
10. Subjects who are deficient in cortisol or thyroid at screening will be excluded until hormone 
abnormalities have been corrected. 
11. Subjects with chronic pain who are being managed with narcotics will be excluded as the 
effects of central nervous system depressants may interfere with study test results. 
12. Subjects with a history of inflammatory bowel disease, Celiac disease or active diverticular 
disease.  
13. Subjects with MRI incompatible devices. 
14. Subjects with severe claustrophobia. 
15. Other medical condition or medication administration deemed exclusionary by the study 
investigators. 
 
 
Household Control Inclusion criteria  
1. Ages 18 and up. 
2. Lives in same household as paired mTBI subject that meets inclusion/exclusion criteria. 
3. Participant is willing and able to give informed consent for participation in the study. 
 
 
Household Control Exclusion criteria 
1. Significant heart, liver, kidney, blood or respiratory disease. 
2. Uncontrolled Diabetes mellitus. 
3. Any history of a recently (12 months) diagnosed cancer other than a skin cancer (excluding 
melanoma). 
4. Current alcohol or drug abuse. 
5. Premorbid history of psychiatric disorder.  
6. Premorbid history of head trauma. 

 
26 
7. Pregnancy or become pregnant during the trial. 
8. Subjects who are deficient in thyroid at screening will be excluded until thyroid hormone is 
replaced.  
9. Subjects with a history of inflammatory bowel disease, Celiac disease or active diverticular 
disease.  
10. Other medical condition or medication administration deemed exclusionary by the study 
investigators. 
 
ARM 2:  
 
mTBI Inclusion criteria 
1. Male or female with a diagnosis of mild TBI.  
2. At least 6-month post-injury. 
3. Ages 18 to 70 years. 
4. Participant is willing and able to give informed consent for participation in the study. 
 
mTBI Exclusion criteria  
1. Unable to walk unassisted. 
2. Significant heart, liver, kidney, blood or respiratory disease. 
3. History of chest pain or coronary heart disease. 
4. Uncontrolled Diabetes mellitus.  
5. Any history of a recently (12 months) diagnosed cancer other than a skin cancer (excluding 
melanoma). 
6. Current alcohol or drug abuse. 
7. Premorbid history of psychiatric disorder.  
8. Premorbid history of head trauma. 
9. Pregnancy or become pregnant during the trial. 
10. Subjects who are deficient in cortisol or thyroid at screening will be excluded until hormone 
abnormalities have been corrected. 
11. Subjects with chronic pain who are being managed with narcotics will be excluded as the 
effects of central nervous system depressants may interfere with study test results. 
12. Subjects with a history of inflammatory bowel disease, Celiac disease or active diverticular 
disease.  
13. Other medical condition or medication administration deemed exclusionary by the study 
investigators. 
 
Healthy Control Inclusion criteria  
1. Ages 18-70 years. 
2. Participant is willing and able to give informed consent for participation in the study. 
 
Healthy Control Exclusion criteria 
1. Significant heart, liver, kidney, blood or respiratory disease. 
2. Uncontrolled Diabetes mellitus. 
3. Any history of a recently (12 months) diagnosed cancer other than a skin cancer (excluding 
melanoma). 
4. Current alcohol or drug abuse. 
5. Premorbid history of psychiatric disorder.  
6. Premorbid history of head trauma. 
7. Pregnancy or become pregnant during the trial. 

 
27 
8. Subjects who are deficient in thyroid at screening will be excluded until thyroid hormone is 
replaced.  
9. Subjects with a history of inflammatory bowel disease, Celiac disease or active diverticular 
disease.  
10. Other medical condition or medication administration deemed exclusionary by the study 
investigators. 
 
ARM 3 (PASC):  
 
Inclusion criteria  
 
1. Male or female with a history of COVID with diagnosis confirmed by PCR test.  
2. Minimum of 6 months since diagnosis of COVID by PCR test.  
3. Ages 18 to 70 years. 
4. Score of 3 or higher on any question 1-3 of the Brief Fatigue Inventory (BFI) questionnaire. 
5. Participant is willing and able to give informed consent for participation in the study. 
 
Exclusion criteria  
 
1. Current COVID infection. 
2. Unable to walk unassisted. 
3. Significant heart, liver, kidney, blood or respiratory disease as determined by Principal 
Investigator.  
4. Uncontrolled diabetes mellitus.  
5. Any history of a recently (12 months) diagnosed cancer other than a skin cancer (excluding 
melanoma). 
6. Current alcohol or drug abuse. 
7. History of psychosis.  
8. Pregnancy or become pregnant during the trial. 
9. Subjects who are being managed with narcotics will be excluded as the effects of central 
nervous system depressants may interfere with study test results. 
10. Other medical condition or medication administration deemed exclusionary by the study 
investigators. 
 
 
 
Sources of materials. We will obtain blood, urine, fecal, questionnaire and imaging data from the 
mTBI and PASC subjects and blood, urine, fecal and questionnaire data from the control subjects.  
All data/samples will be collected solely for the purpose of experimentation, except for the safety 
check visit for mTBI and PASC patients at month 1. The blood will be used for screening and to 
measure metabolites, amino acids and hormones. Fecal samples will be used for determination of 
the GI microbiome. Questionnaire data will be used to assess GI health and quality of life.  
Recruitment Methods and Consenting Process (Arm 1) 
a. 
Potential mTBI subjects may be patients of the investigators. 
 
b. 
mTBI subjects will be recruited through ads and flyers around the community as well as in 
Dr. Urban’s Internal Medicine Endocrinology clinic. The study will also be listed on the UTMB 
clinical research website, researchmatch.org and clinicaltrials.gov. Potential subjects may be 

 
28 
previous research subjects of the investigator. Interested mTBI subjects in clinic will be 
directed to call the study team for more information. Interested mTBI subjects calling the study 
team in response to a physician referral, ad, flyer, researchmatch.gov or CT.gov will be given 
detailed information regarding the study. They will be informed that to participate in this study 
they must have an eligible partner in their household willing to participate with them. The study 
team will email (postal mail, if needed) a study information packet that will include a Fast Fact 
sheets for both groups explaining the screening process (including all risks of the overnight 
fast that is required for the screening process) and the study in bulleted points and the consent 
forms for both mTBI and control groups (see attached Fast Fact sheet).  Potential mTBI 
subjects can read the study information packet with their families and decide if they would like 
to enroll. If interested, the potential mTBI subject will contact the study team for a phone pre-
screening to go over eligibility requirements (pre-screening) for the study (see attached pre-
screening sheet). If potential mTBI subject passes the pre-screening, the household control 
subject will have the detailed study explained to them and if they are interested, will be asked 
to complete a phone pre-screening. If still interested, the potential mTBI subject and the 
potential household control subject will be asked to come to the ITS-CRC at a time that is 
mutually convenient for both the subjects and the study team for consenting and medical 
screening, including fasting labs. 
 
 
c. 
It is anticipated that mTBI subjects and their household control will want to be together for the 
consenting process. In this circumstance, the study team will go over in detail the consent 
forms for both mTBI group and household control group with both subjects in a private room 
and then they will be given time alone together to discuss whether they would like to enroll. 
Each participant will be given the opportunity to speak to the study team alone, if they choose 
to.  
 
d. 
To minimize the possibility of coercion or undue influence all subjects will be given a copy of 
the approved consent forms and encouraged to discuss with their families prior to meeting 
the coordinator for the consenting process. The study team will be make it very clear to the 
potential mTBI participants that to meet inclusion criteria for this study, they must have an 
eligible household partner. If either one of the pair withdraws consent or is terminated, the 
other will be terminated by the study team.  
 
e. 
We are requesting an alteration of the consenting process so that we can obtain written 
consent and perform the medical screening in the same visit. The medical screening requires 
an overnight fast, which the IRB deems as research. Subjects will be provided a copy of the 
approved consent form for their review prior to their consenting/screening visit. The risk 
involved is an overnight fast. An overnight fast for medical tests is routine for medical care 
and would not require consent outside the scope of research. When subject arrives at CRC 
for the screening visit, the study team will begin with the consenting process as described 
above. We are only requesting the waiver of written consent for fasting to occur during the 
consenting visit. Written consent would be obtained prior to any study related procedures.  
 
Recruitment Methods and Consenting Process (Arm 2) 
 
a. Potential mTBI subjects may be patients of the investigators. 
 
b. mTBI subjects will be recruited through ads and flyers around the community as well as in 
Dr. Urban’s Internal Medicine Endocrinology clinic. The study will also be listed on the UTMB 

 
29 
clinical research website, researchmatch.org and clinicaltrials.gov. Potential subjects may be 
previous research subjects of the investigator. Interested mTBI subjects in clinic will be 
directed to call the study team for more information. Interested mTBI subjects calling the study 
team in response to a physician referral, ad, flyer, researchmatch.gov or CT.gov will be given 
detailed information regarding the study. The study team will email (postal mail, if needed) a 
study information packet that will include a Fast Fact sheets explaining the screening process 
(including all risks of the overnight fast that is required for the screening process) and the 
study in bulleted points and the consent form (see attached Fast Fact sheet).  Potential mTBI 
subjects can read the study information packet with their families and decide if they would like 
to enroll. If interested, the potential mTBI subject will contact the study team for a phone pre-
screening to go over eligibility requirements (pre-screening) for the study (see attached pre-
screening sheet). If potential mTBI subject passes the pre-screening and if still interested, the 
potential mTBI subject will be asked to come to the ITS-CRC at a time that is mutually 
convenient for both the subject and the study team for consenting and medical screening, 
including fasting labs.  
 
Healthy controls will be recruited using the UTMB clinical research website, 
researchmatch.org and clinicaltrials.gov. Potential subjects may be previous research 
subjects of the investigator. Interested healthy subjects contacting the study team in response 
to a physician referral, ad, flyer, researchmatch.gov or CT.gov will be given detailed 
information regarding the study. The study team will email (postal mail, if needed) a study 
information packet that will include a Fast Fact sheets explaining the screening process 
(including all risks of the overnight fast that is required for the screening process) and the 
study in bulleted points and the consent form (see attached Fast Fact sheet).  Potential 
healthy control subjects can read the study information packet with their families and decide 
if they would like to enroll. If interested, the potential healthy control subject will contact the 
study team for a phone pre-screening to go over eligibility requirements (pre-screening) for 
the study (see attached pre-screening sheet). If potential healthy control subject passes the 
pre-screening and if still interested, the potential healthy control subject will be asked to come 
to the ITS-CRC at a time that is mutually convenient for both the subject and the study team 
for consenting and medical screening, including fasting labs. 
 
 
c. All subject will have privacy at each of their visits to the ITS-CRC. All subjects will be given a 
private room for consenting, screening as well as each study visit.  
 
d. To minimize the possibility of coercion or undue influence all subjects will be given a copy of 
the approved consent forms and encouraged to discuss with their families prior to meeting 
the coordinator for the consenting process.  
 
e. We are requesting an alteration of the consenting process so that we can obtain written 
consent and perform the medical screening in the same visit. The medical screening requires 
an overnight fast, which the IRB deems as research. Subjects will be provided a copy of the 
approved consent form for their review prior to their consenting/screening visit. The risk 
involved is an overnight fast. An overnight fast for medical tests is routine for medical care 
and would not require consent outside the scope of research. When subject arrives at CRC 
for the screening visit, the study team will begin with the consenting process as described 
above. We are only requesting the waiver of written consent for fasting to occur during the 
consenting visit. Written consent would be obtained prior to any study related procedures.  

 
30 
Recruitment Methods and Consenting Process (Arm 3) 
 
a. Potential PASC subjects may be patients of the investigators. 
 
b. PASC subjects will be recruited through ads and flyers around the community as well as 
flyers in Dr. Urban’s Internal Medicine Endocrinology clinic, the UTMB post-COVID clinic 
and surrounding post-COVID clinics. The study will also be listed on the UTMB clinical 
research website, researchmatch.org and clinicaltrials.gov. Potential subjects may be 
previous research subjects of the investigator. Interested subjects in clinic will be directed to 
call the study team for more information. Interested subjects calling the study team in 
response to a physician referral, ad, flyer, researchmatch.gov or CT.gov will be given detailed 
information regarding the study. The study team will email (postal mail, if needed) a study 
information packet that will include a Fast Fact sheets explaining the screening process 
(including all risks of the overnight fast that is required for the screening process) and the 
study in bulleted points and the consent form (see attached Fast Fact sheet).  Potential 
subjects can read the study information packet with their families and decide if they would like 
to enroll. If interested, the potential subject will contact the study team for a phone pre-
screening to go over eligibility requirements (pre-screening) for the study (see attached pre-
screening sheet). If potential subject passes the pre-screening and if still interested, the 
potential subject will be asked to come to the ITS-CRC at a time that is mutually convenient 
for both the subject and the study team for consenting and medical screening, including 
fasting labs.  
 
 
c. All subject will have privacy at each of their visits to the ITS-CRC. All subjects will be given a 
private room for consenting, screening as well as each study visit.  
 
d. To minimize the possibility of coercion or undue influence all subjects will be given a copy of 
the approved consent forms and encouraged to discuss with their families prior to meeting 
the coordinator for the consenting process.  
 
e. We are requesting an alteration of the consenting process so that we can obtain written 
consent and perform the medical screening in the same visit. The medical screening requires 
an overnight fast, which the IRB deems as research. Subjects will be provided a copy of the 
approved consent form for their review prior to their consenting/screening visit. The risk 
involved is an overnight fast. An overnight fast for medical tests is routine for medical care 
and would not require consent outside the scope of research. When subject arrives at CRC 
for the screening visit, the study team will begin with the consenting process as described 
above. We are only requesting the waiver of written consent for fasting to occur during the 
consenting visit. Written consent would be obtained prior to any study related procedures.  
 
 
 
Subject reimbursement for time and travel.   
• mTBI and  subjects will receive $50 for screening; $150 each month 0 and month 6 visits, 
$25 each fecal collection in month 1-5, and $25 each month (6 months) for rhGH 
intervention. If they complete the entire protocol, they will be reimbursed $625 for time 
and travel.  

 
31 
• PASC subjects will receive $50 for screening; $150 each month 0 and month 6 visits, $50 
for the month 12 visit, $25 each fecal collection in month 1-5 and month 9, and $25 each 
month (9 months) for rhGH intervention. If they complete the entire protocol, they will be 
reimbursed $775 for time and travel.  
 
•  Control subjects will receive $25 for screening; $50 each month 0 and month 6 visits, $25 
each fecal collection in month 1-5. If they complete the entire protocol, they will be 
reimbursed $250 for time and travel.  
 
Potential Risks   
 
The potential risks for mTBI and PASC subjects enrolled in this project will be the following: 
 
Vital Signs.  There are no known risks of vital signs being performed.   
 
Phlebotomy.  All patients will undergo blood draws for the medical screening tests and periodically 
throughout the study. The risks of phlebotomy are pain, infection, bruising and introduction of 
blood borne pathogens. Aseptic technique will be used to minimize these risks. 
 
Blood draws. Repeated blood draws may expose to the risk of anemia. mTBI subjects will have 
approximately 120 ml of blood taken in the course of the entire study. PASC subjects will have 
approximately 175 ml of blood taken in the course of the entire study.  
 
Fasting. The risks of fasting include fatigue, headache, hypoglycemia and dehydration. 
 
Glucagon Stimulation Testing. The known side effects of the glucagon stimulation test are 
headache and nausea and possible vomiting.  
 
Electrocardiogram (EKG).  This is a non-invasive, painless test. There is a risk of irritation or a 
rash on the skin from the electrodes. 
 
DEXA scan.   The measurement of lean and fat mass by DEXA involves a brief exposure (~15 
min) to a low dose of radiation (~ 0.05 mrem/whole body scan), calculated to be approximately 
equal to a 2 h airplane flight per scan. Otherwise, there are no known risks of measuring body 
composition. 
 
Indirect calorimetry. There are no known risks involved with these measurements.  
 
Magnetic Resonance Imaging (MRI) (Arm 1 only). As MRI is a procedure that does not involve 
radiation and is non-invasive, the main risks are accidental injury resulting from the presence of 
metal objects on one’s clothes or person (e.g. jewelry, piercings, implants, pacemakers, some 
types of tattoos, IUDs).  In addition, some individuals may experience claustrophobia due to the 
confined space within the scanner. 
 
Cognitive Testing. There are no known risks involved with this testing. 
 
Fecal Sampling.  There is no known risk of this procedure. 
 

 
32 
Nasal Swab. Risks include momentary pain and a chance for minor bleeding from the nose similar 
to the risks associated with nasopharyngeal SARS-CoV-2 testing.  
 
Performance testing and 6-minute walk.  The exercise tests may cause muscle soreness, cramps, 
dizziness, and possibly irregular heartbeats. The risks of the 6-minute walk include falling, 
elevated heart rate and elevated blood pressure. All subjects will be accompanied by a trained 
staff member.   
 
Questionnaires.   There is no known risk to completing the questionnaires listed in this study.  
 
Recombinant Human Growth Hormone (rhGH). The potential risks of taking growth hormone 
include weight gain, joint pain, and increased blood glucose. In addition, Carpal Tunnel Syndrome, 
a condition characterized by numbness or pain in the wrists and fingers, has been associated with 
growth hormone therapy. These effects are modifiable with dose adjustment and are unlikely due 
to the relatively brief period of time that patients will be receiving growth hormone during the 
course of the study. An IGF-1 lab will be drawn at the 1-month time point. If the IGF-1 value is 
over 400 ng/ml, the dose of GH will not be increased.  
 
Confidentiality.  Divulgation of personal sensitive data is a general risk of clinical investigations 
involving human subjects. 
 
The potential risks for control subjects enrolled in this project will be the following: 
 
Vital Signs.  There are no known risks of vital signs being performed.   
 
Phlebotomy.  All patients will undergo blood draws for the medical screening tests and periodically 
throughout the study. The risks of phlebotomy are pain, infection, bruising and introduction of 
blood borne pathogens. Aseptic technique will be used to minimize these risks. 
 
Blood draws. Repeated blood draws may expose to the risk of anemia. Household controls will 
have approximately 100 ml of blood taken in the course of the entire study.  
 
Fasting. The risks of fasting include fatigue, headache, hypoglycemia and dehydration. 
 
Fecal Sampling.  All subjects will collect fecal samples at monthly intervals throughout the study. 
There is no known risk of this procedure.  
 
Questionnaires.   There is no known risk to completing the questionnaires listed in this study.  
 
Confidentiality.  Divulgation of personal sensitive data is a general risk of clinical investigations 
involving human subjects. 
 
B. Adequacy of Protection Against Risks 
 
Recruitment and informed consent.  Subjects will be recruited through Houston/Galveston area 
using flyers and other advertisements. Subjects may also be patients or previous research 
subjects of the investigators. The study will be listed on the researchmatch.org and clinicaltrial.gov 
registries. The details of the experimental procedures, including all the risks and benefits, will be 
explained by a study coordinator at the initial time of screening. At this time, they will be asked to 

 
33 
read and sign the consent form, approved by the IRB at UTMB. A copy of the signed consent form 
will be given to the subject.   
 
Protections against risks.  All key personnel have completed and passed the certification exam of 
the NIH-mandated course on protection of human subjects. The screening tests will allow us to 
exclude a priori subjects with potentially higher risk of developing complications.  Randall Urban, MD 
will oversee the medical aspects of the experiments.  Protections against risks for all patients will be 
the following: 
 
Vital Signs. There are no known risks of this procedure.  
 
Phlebotomy.  The use of aseptic technique will be used to minimize the risk of infection, but will 
not eliminate it completely. Some patients may experience a sudden drop in blood pressure in 
response to the placement of catheters. Symptoms may include lightheadedness, nausea and 
possibly vomiting. There are no long-term effects associated with this response. In our 
experience, symptoms occur in 3.3% of our healthy subjects. All patients experiencing this 
response will be examined by a physician and given the option of discontinuing the study. If the 
physician, PI, study investigators, and patient find no reason to stop the study, the patient will be 
allowed to continue.  
 
Blood draws. No more than ~40 ml of blood will be drawn at any visit. This is less than one tenth 
of a typical blood donation, and in adult individuals with normal blood count does not expose to 
the risk of anemia. TBI subjects will have less than 120 ml of blood  drawn over the 6 month period 
of the study. PASC subjects will have less than 175 ml of blood drawn over the 12 month period 
of the study. Should we estimate blood losses from other reasons (complications of any 
procedure) to exceed 500 ml for the entire study, the subjects will be counseled about avoiding 
blood donations or participating in other studies involving blood draws until a normal hemoglobin 
value is restored.   
 
Fasting.  All subjects will be made aware of the risks of overnight fasting. They will be advised to 
drink water the night before and the morning of their visits. All subjects will be fed a meal during 
or after the completion of their study visits.   
 
Glucagon Stimulation Test.  Subjects will be made aware of the risks of the test.  
 
Electrocardiogram. Subjects will be made aware of the risks of the test.  
 
DEXA scan.  The amount of radiation absorbed with each scan is very low (similar to the dose 
received during a 2-hour flight).  Subjects will be made aware of this exposure level prior to the 
scans. 
 
Indirect calorimetry. There are no risks involved with these measurements.  
 
Magnetic Resonance Imaging. Subjects will be screened for the presence of implanted medical 
devices, embedded metal or other material for which MRI is contraindicated according to standard 
UTMB safety guidelines.  To protect against loud noises, participants will wear foam earplugs and 
/ or headphones to reduce the loud noises made by the scanner. To reduce claustrophobia, 
subjects will be able to talk to investigators throughout the study via intercom, and will be able let 
us know right away if they want to stop the study and get out of the scanner.  
 

 
34 
Fecal Sampling. There are no known risks of this procedure.  
 
Nasal Swab.  Care will be taken to minimize pain and/or bleeding.  
 
Performance testing and 6-minute walk. Risk of muscle soreness or cramps can be reduced or 
avoided with an adequate warm-up. The subjects will be accompanied by a qualified staff member 
at all times.  
 
Questionnaires. There are no known risks of this procedure.  
 
 
Recombinant Human Growth Hormone Administration. The potential risks of taking growth 
hormone (weight gain, increased blood glucose, joint pain, and Carpal Tunnel Syndrome), will be 
described in the consent form. These effects are unlikely due to the relatively brief period of time 
that subjects will be receiving growth hormone during the course of the 6 or 9-month treatment 
period. An IGF-1 lab will be drawn at the 1-month time point. If the IGF-1 value is over 400ng/ml, 
the dose of GH will not be increased.  
 
Confidentiality.  Only the investigators, the study personnel, and the Medical Records department of 
the UTMB Hospital will have access to the subjects’ personal information.  All data containing the 
name of the patients will be locked in the PI office. To preserve confidentiality, immediately after 
enrollment each subject will be assigned a code by which each research sample will be identified for 
further analysis, thus avoiding identification by non-qualified individuals. 
 
C. Potential Benefits of the Proposed Research to the Subjects and Others 
 
The only potential benefits for the participation in this protocol are related to the knowledge of the 
results of the screening tests that will be released to the volunteer.  No other benefits are expected 
for the subjects.  The knowledge collected from the present studies may be of benefit to society, 
as these studies will help develop the scientific basis for designing treatments for improving the 
symptom complex of mTBI and PASC (cognition, performance and perceptual fatigue) in 
individuals with mTBI or PASC. 
 
D. Importance of Knowledge to be Gained 
 
Characterization of the GI microbiome in patients with history of mTBI and PASC in relation to healthy 
controls will provide further insight into the mechanisms and regulation of the gut-brain axis. 
Recognition that the microbiome of mTBI and PASC patients are consistently altered will aid the 
development of future diagnostic and/or treatment plans for mTBI and PASC patients. 
 
 
E. Data Safety and Monitoring Plan 
Study Title:  
Brain and Gut Plasticity in mild TBI or post-acute COVID syndrome Following Growth Hormone 
Therapy 
Type of Research Data or Events to be Monitored:   

 
35 
Total subject accrual, including screen fails, dropouts and terminations will be monitored as well as 
adverse events, protocol deviations, violations and unanticipated problems.  Since the risk level 
associated with this study is estimated to be moderate, subjects will be monitored by the principal 
investigators for safety throughout the study (i.e. subjects’ lab values, medical history, reactions to 
injections, and rhGH treatment).  
Methods and Frequency of Analysis:  
Plan for Monitoring and Safety Review: 
a.   Randall Urban, MD, the Principal Investigator is the individual responsible for monitoring the 
safety environment of the participants. He will work with, Dr. Dillon, or the study coordinator, to 
oversee safety of the participants.  
b.   Thorough monitoring of the recruitment, enrollment, retention, informed consent process, 
adverse events, study procedures, and the evaluation of primary and secondary endpoints will be 
carried out.   
c.   Potential subjects will be informed of all procedures involved in the study.  If screening reveals 
any clinical abnormalities, subjects will be advised, by either a study team physician or nurse 
practitioner, to consult his/her primary physician.  If the subject agrees to participate, written consent 
will be obtained in the presence of one of the following: the Principal Investigator, Co-Investigator, or 
Study Coordinator.  There will always be at least one qualified member of the research team or one 
CRC nurse with the subject during the study protocol. 
Plan for Data Management: 
a. All the study data will be collected by the research team and recorded on case report forms.  To 
preserve  confidentiality, immediately after enrollment each subject will be assigned a code by 
which each research sample will be identified for further analysis to avoid identification by non-
qualified individuals.   Dr. Urban, the Principal Investigator, is the individual responsible for 
storage of data.  Recognizable personal subject information will be stored in Dr. Urban’s 
laboratory in a locked cabinet. 
 
b.   Data will be reviewed on a weekly basis by the PIs and the research team. 
c.   The conditions that would necessitate early termination of the study include non-compliance with 
study medication dosing.  
d.   The PI with the aid of the Co-Investigators and the Study Coordinator will perform aggregate 
analysis of data and adverse events. 
 
Persons Responsible for Data Monitoring:  
The ultimate responsibility for data and safety monitoring, and submitting reports of unanticipated 
problems, adverse events, protocol deviations and protocol violations rests with the Principal 
Investigator, Randall Urban, MD. Every effort will be undertaken to monitor and minimize the risks 

 
36 
to subjects.  Prior to obtaining informed consent, subjects will be encouraged to thoroughly read 
the informed consent form and ask questions regarding the outlined procedures and risks. To 
ensure ongoing protection of study subjects all procedures will be performed under the 
supervision of Randall Urban, M.D., or a physician willing to provide backup medical coverage.  All 
study physicians will be familiar with the study protocol. 
Reporting Unanticipated Problems, Adverse Events, Protocol Deviations and Protocol 
Violations: 
a.   Dr. Urban, the Principal Investigator, is the individual responsible for monitoring and reporting 
the occurrence of unanticipated problems, adverse events, protocol deviations and protocol 
violations throughout the study.  The subjects will be monitored throughout the study at screening 
and follow up visits.  
b.   Anticipated Adverse Events, as discussed above will be included in the consent form.  All other 
anticipated adverse events will be addressed by the PI and study team. If an adverse event occurs 
Dr. Urban will be immediately notified and a note will be entered in to the subject’s CRC medical 
chart using the grading scale listed below.  
c.   Adverse Event Grading Scale (UTMB – CRC Scale): 
0 = No Adverse Event or within normal limits 
1 = Mild Severity: Transient laboratory test alterations; discomforts noted but no disruption of daily 
activities; no therapy, or only symptomatic therapy required. 
2 = Moderate Severity: Laboratory test alterations indicating injury without long-term risk; discomfort 
sufficient to modify normal daily activity; specific therapy required (i.e., more than symptomatic). 
3 = Serious Severity: Laboratory test indicating a serious health threat or permanent injury; 
incapacity, inability to work, inability to perform normal daily activity; hospitalization required or 
prolonged; emergency treatment required; life-threatening events; death.     
The attribution scale assesses the relation of the event to the study procedures. The Principal 
Investigator will judge whether or not an adverse event is: 1) not related; 2) possibly related; 3) 
probably related; 4) definitely related to the study procedures and interventions. 
All unanticipated, serious, fatal and/or life-threatening adverse events will be reported to the IRB, 
CRC Program Director and Pfizer, Inc within 24 hours of occurrence.  The PI and UTMB 
Institutional Review Board (IRB) are responsible for determining whether modifications to the 
protocol and consent form are required. If a determination is made that participants are found to 
be exposed to excessive risks in relation to anticipated benefits, the study will be immediately 
suspended. Studies will not resume until modifications are made that are deemed to result in an 
acceptable risk/benefit ratio by the PIs and IRB. Aggregate reports of adverse events will be 
prepared on an annual basis and forwarded to the IRB and CRC at annual review. 
 
Stopping Rules: 

 
37 
Pairs enrolled in Arm 1: 
 
 
mTBI Subjects: 
1. If paired household control subject withdraws consent, mTBI subject will be terminated 
from the study.  
2. If subject reports they have missed more than 7 consecutive days of study medication 
administration, they will be terminated. 
 Household Control Subjects: 
1. If paired mTBI subject withdraws consent or is terminated, household control subject 
will be terminated from the study.  
Subjects enrolled in Arm 2 & 3: 
mTBI/PASC Subjects: 
1. If subject reports they have missed more than 7 consecutive days of study medication 
administration, they will be terminated. 
 
Procedures and Time Frames for Communicating Outcomes: 
Monitoring Reports will be prepared and forwarded to the IRB on an annual basis.  
 
Precautions for Maintaining Data Integrity: 
Careful monitoring of the recruitment, enrollment, retention, adverse events, and study 
procedures will help to protect the safety of study subjects, the quality of data, and the integrity of 
the study. As part of the safety plan for this study, the PI will review individual study subject records 
to ensure that appropriate mechanisms to protect the safety of study participants are being 
followed, that protocol requirements are being adhered to, and that data is accurate, complete, 
and secure. Subject records include consent forms, case report forms, flow of data forms, 
laboratory specimen records, inclusion/exclusion forms, cumulative toxicities and/or adverse 
event logs, and medical charts.   
 
Records Retention 
The investigator shall retain the records for 15 years.  

 
38 
 
Inclusion of Women and Minorities 
Women and men will be included, as GENOTROPIN is approved for both.  
Minorities will be included in the proportion found in the general population (see Targeted 
Enrollment Table)  
 
Targeted/Planned Enrollment Table 
Study Title: Brain and Gut Plasticity in mild TBI or post-acute COVID Syndrome Following 
Growth Hormone Therapy 
Total Planned Enrollment: Up to 125 subjects. We would like to complete n=50 TBI subjects 
(enrolled in arm 1 and arm 2), n=50 control subjects (enrolled in arm 1 and arm 2) and n=25 PASC 
subjects (arm 3). 
Targeted/ Planned Enrollment: Number of Subjects 
Ethnic Category 
Sex/Gender 
Females 
Males 
Total 
Hispanic or Latino 
13 
12 
25 
Not Hispanic or Latino 
50 
50 
100 
Ethnic Category: Total of All Subjects * 
63 
62 
125 
Racial Categories 
 
American Indian/Alaska Native 
0 
0 
0 
Asian 
0 
0 
0 
Native Hawaiian or Other Pacific Islander  
0 
0 
0 
Black or African American  
13 
12 
25 
White 
50 
50 
100 
Racial Categories: Total of All Subjects * 
63 
62 
125 
 
 
Inclusion of Children.  
Children will not be included in this study. The age range for inclusion is 18 and over.  

 
39 
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