Clinical trial NCT03327181: Short Chain Fatty Acid Metabolism in COPD
Official title: Short-chain Fatty Acid Metabolism in Chronic Obstructive Pulmonary Disease
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Chronic Obstructive Pulmonary Disease
Keywords: short chain fatty acid metabolism
Lead sponsor: Texas A&M University
Sponsor class: OTHER
First posted: 2017-10-31
Enrollment: 60
Sex: ALL
Minimum age (years): 45
Maximum age (years): 100
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: OTHER

Brief summary: The short chain fatty acid (SCFA) metabolism has not been studied in subjects suffering from COPD. The purpose of this study is to compare the SCFA metabolism in COPD patients to healthy matched controls. This protocol is an extension of recent studies about protein digestion and absorption abnormalities in COPD patients. The investigators hypothesize that SCFA production might be lower in COPD patients than in healthy subjects.

Detailed description: Short-chain fatty acids (SCFAs) are straight or branched-chain fatty acids produced by the intestinal microbiota mainly through fermentation of undigested carbohydrates, but also through degradation of dietary and endogenous proteins. With a share of 90 to 95 %, acetate (C2), propionate (C3), and butyrate (C4) are the most common SCFAs in the colon (3). The molar ratios of acetate to propionate to butyrate are on average approximately 60:20:20 throughout the whole colon. Several human studies tried to determine the in situ production of SCFAs by measuring their content in feces (5-8). But fecal SCFA concentrations do not accurately represent the concentrations in more proximal regions of the colon, because colonocytes absorb more than 95 % of SCFAs to use them as an energy source. Further, the measurement of plasma SCFA concentrations is inaccurate because SCFA plasma levels are low due to high metabolism in colonocytes and liver. Thus, stable isotope studies are needed to examine the colonic production and metabolic fate of SCFAs in healthy and diseased subjects.

SCFAs seem to have anti-inflammatory and immune modulating effects. In COPD an enhanced pulmonary inflammatory response causes a combination of small airways disease (e.g., obstructive bronchiolitis) and/or a destruction of lung parenchyma (emphysema). This leads to a progressive and persistent airflow limitation. Smoking and the exposure to polluted air are main risk factors causing COPD. In a mouse model, a diet rich in whey proteins attenuated emphysema through the suppression of respiratory inflammation. This might have been related to a high colonic SCFA concentration due to the diet. Young et al. proposed that in smokers SCFAs might mitigate both the innate-mediated systemic inflammation controlled by the liver and the inflammatory responses in the lung.

Moreover, Nielsen et al. found that gastrointestinal diseases are significantly more prevalent in COPD patients (15 %) than in patients with other diseases (9%). This might have an influence on the SCFA production in the colon. Gastrointestinal problems may also be assessed through the usage of validated questionnaires.

Eligibility criteria: Inclusion criteria COPD subjects:

* Ability to walk, sit down and stand up independently
* Age 45 years - 100 years
* Ability to lie in supine or elevated position for 1.5 hours
* Diagnosis of moderate to very severe chronic airflow limitation and compliant to the following criteria: FEV1 \< 70% of reference FEV1
* Clinically stable condition and not suffering from a respiratory tract infection or exacerbation of their disease (defined as a combination of increased cough, sputum purulence, shortness of breath, systemic symptoms such as fever, and a decrease in FEV1 \> 10% compared with values when clinically stable in the preceding year) at least 4 weeks prior to the first test day
* Shortness of breath on exertion
* Willingness and ability to comply with the protocol

Inclusion criteria control subjects:

* Healthy male or female according to the investigator's or appointed staff's judgment
* Ability to walk, sit down and stand up independently
* Age 45 years - 100 years
* Ability to lay in supine or elevated position for 1.5 hours
* No diagnosis of COPD
* Willingness and ability to comply with the protocol

Exclusion Criteria all subjects:

* Any condition that may interfere with the definition 'healthy subject' according to the investigator's judgment (healthy subjects only)
* Subjects 86 years and older that fail to get physician eligibility confirmation
* Insulin dependent diabetes mellitus
* Established diagnosis of malignancy
* History of untreated metabolic diseases including hepatic or renal disorder
* Presence of acute illness or metabolically unstable chronic illness
* Presence of fever within the last 3 days
* Any other condition according to the PI or nurse that was found during the screening visit, that would interfere with the study or safety of the patient
* Use of protein or amino acid containing nutritional supplements within 5 days of first study day
* Use of short course of oral corticosteroids within 4 weeks preceding first study day
* Failure to give informed consent or Investigator's uncertainty about the willingness or ability of the subject to comply with the protocol requirements
* (Possible) pregnancy
* Already enrolled in another clinical trial and that clinical trial interferes with participating in this study

When during the period from enrollment to the test day any condition causing the subject to not meet inclusion criteria or to meet exclusion criteria, the subject will be excluded from the study.

Primary outcomes:
measure: whole body short-chain fatty acid metabolism
timeFrame: -10, 2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60 min
Secondary outcomes:
measure: Fat free mass measured using dual-energy x-ray absorptiometry
timeFrame: 1 day
measure: Fat mass measured using dual-energy x-ray absorptiometry
timeFrame: 1 day
measure: Bone density measured using dual-energy x-ray absorptiometry
timeFrame: 1 day
measure: handgrip strength dynamometry
timeFrame: 1 day
measure: Micro-respiratory pressure meter measurement
timeFrame: 1 day
measure: moving balance platform measurement
timeFrame: 1 day
measure: Group differences in attention and executive functions as measured by Trail Making Test (TMT),
timeFrame: 1 day
measure: Group differences in attention and executive functions as measured by Stroop Color-Word Test (SCWT),
timeFrame: 1 day
measure: Group differences in somatosensory functions as measured by vibrotactile behavioral battery
timeFrame: 1 day
measure: Group differences in gut function as reported by "The Gastrointestinal Symptom Rating Scale"
timeFrame: 1 day
measure: Group differences in physical activity as reported by "International Physical Activity Questionnaire"
timeFrame: 1 day
measure: COPD Assessment Test
timeFrame: 1 day
Other outcomes:
Locations:
city: College Station
country: United States
facility: Texas A&M University
state: Texas
Study officials:
affiliation: Texas A&M University
name: Marielle Engelen, PhD
role: PRINCIPAL_INVESTIGATOR
References: