bluuebunny/crossref_metadata_2025 huggingface dataset:
Up‐regulating Heme Oxygenase System Potentiates Pancreatic Repair by Enhancing Proteins of Regeneration
Authors: Mishra Manish , Ndisang Joseph Fomusi
Published: November 2023

Background

Autoimmune‐mediated enhanced beta cell destruction and resultant insulin insufficiency poses a great health risk in type‐1 diabetes mellitus affected individuals. Our previous observations have shown that up‐regulation of the heme oxygenase (HO) by HO‐inducer hemin improved pancreatic lesion in streptozotocin‐induced diabetes, yet the hemin mediated pancreatic tissue repair mechanisms are still unclear. Accordingly, the aim of this study was to examine the effects of up‐regulating the HO system on proteins of regeneration during pancreatic repair in streptozotocin‐induced type‐1 diabetic animal model.

Methods/Results

Streptozotocin (STZ) was used to induce diabetes, while HO system was up‐regulated with hemin or inhibited with chromium mesoporphyrin. Histology/morphology, spectrophotometry, enzyme‐immunoassay (EIA), enzyme‐linked immunosorbent assay (ELISA) and Western‐immunoblotting were used to demonstrate pancreatic tissue injury and repair.

Our data demonstrated that treatment with hemin to STZ‐induced diabetic animals effectively suppressed the pancreatic histopathological lesions (vacuolization, interstitial edema, mononuclear cell infiltration and fibrosis), while enhanced several proteins implicated in pancreatic repair/regeneration and beta cell growth and maturation including Oct3/4, Pax‐2, beta‐catenin, ISL‐1, glucose transporter‐2 (GLUT2), homeodomain protein NKK6.1. Interestingly, hemin treatment also increased the expression of stem cell markers such as cKit and Sca‐1, suggesting the involvement of stem cells and proteins of regeneration during pancreatic repair/regeneration in STZ diabetic animals. Moreover, the restoration of pancreatic morphology was accompanied by increased production of insulin and the potentiation of important proteins of insulin signaling pathway such as insulin‐receptor substrate (IRS‐1), IRS‐2, phosphatidylinositol‐3‐kinase (PI3K) and Glucose transporter‐4 (GLUT4) in skeletal muscles and the liver from STZ diabetic animals. Furthermore, hemin significantly reduced the inflammation and oxidative stress in the pancreas, skeletal muscles and liver, In contrast, these effects were nullified by the HO‐inhibitor, chromium mesoporphyrin.

Conclusion

Taken together, our findings demonstrate that upregulating the HO‐system with hemin is a useful strategy to potentiate proteins of regeneration such as Oct3/4, Pax‐2, beta‐catenin, ISL‐1, GLUT2 and NKK6.1 during the restoration of pancreatic morphology in streptozotocin‐induced diabetic animals. Importantly, the restoration of pancreatic morphology was accompanied by improved insulin production and the potentiation of proteins implicated in insulin signaling and glucose metabolism. Thus, HO‐inducers may open a new horizon in the search for remedies of type‐1 diabetes.

Support or Funding Information

Heart & Stroke Foundation of Saskatchewan, Canada
Measurement of Nitric Oxide with EPR in Whole Blood during Peak Hand Grip Exercise in Women with Metabolic Syndrome
Authors: Barlow Matthew A , Cheeti Upender R , Navarro Juan P , Stephens Kyle , Weaver John M
Published: November 2023

The contribution of bioavailable Nitric Oxide to the change in vascular function during exercise hyperemia is primarily concluded through the lack of functional changes in the presence of eNOS inhibitors. The aim of this study is to utilize EPR techniques to measure the changes in NO production during peak hand grip exercise to identify mechanistic differences of vascular function in women with Metabolic Syndrome compared to healthy controls.

Methods

In this study, 13 participants (5 MetSyn and 8 Controls) performed the procedure of graded handgrip exercise on a dynamic handgrip device while brachial blood flow was continuously measured with Doppler ultrasound and B‐mode (GE Vivid E with 6MHz linear probe). Following a brief rest, individuals were asked to perform handgrip exercise whereby the workload progressively increased in a ramp fashion (0.5 kg·min−1) until the required contraction rate (30 cpm) could no longer be maintained. At rest and immediately after halting exercise at task failure for individual peak resistance, whole blood was drawn into a prepared vaccutainer in a 1:1 venous blood to the metal chelator, defferoxamine (DF), in diethyldithiocarbamate (DETC) Krebs buffer. The samples were immediately flash frozen in liquid nitrogen and stored at −80 degrees Celsius. All pre and peak NO samples were measured and compared with known NO samples using an X‐band electron paramagnetic resonance spectrometer (Bruker Biospin, Karlsruhe, Germany). Whole blood with known concentrations of NO2 (1–10mM) and Na2S2O4 (20 mM) served as a reference.

Results

Whole blood NO increased significantly from rest to peak exercise in both groups (p=0.047) in addition to brachial conductance (p=0.0001). There was no significant difference in the rise in NO during peak exercise between the MetSyn and Control groups (p=0.67) however there is a significant difference in brachial conductance starting, peak and delta between the groups (p=0.021, 0.028, and 0.019).

Conclusion

The whole blood Iron Chelated EPR technique is capable of detecting the degree of change in NO potentially contributing exercise hyperemia in different groups and potentially at variable grades of exercise. Although there is a significant difference in the vascular conductance between the groups, with the number of participants included in this study, there was no difference indicated between the groups for NO at rest and peak exercise.

Support or Funding Information

Research reported in this publication was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number P20GM103451.
Precooling of fanning and hands and feet water immersion attenuates dehydration and thirst during exercise in the heat
Authors: Tokizawa Ken , Oka Tatsuo , Son Su‐young
Published: November 2023

Precooling (i.e., removal of heat from the body immediately prior to exercise) is a popular strategy for alleviating thermal strain. Although whole body water immersion is most commonly used to precool in experimental studies, this method is not always possible in all field settings, or practical. In the present study, we examined the effectiveness of a novel combination of fanning and hands and feet water immersion as practical precooling method on heat strain while wearing protective clothing.

Nine males engaged in 60 min of walking at a moderate speed (2.5 km/h) in a hot environment (37°C, 50%RH) while wearing protective clothing. Before walking, they were exposed to fanning (4 m/s) and spraying over the body and to hands and feet water immersion (18°C) for 30 min (FAN+WI).

Rectal temperature and heart rate at the end of walking were lower in WI+FAN trial than in the control trial (37.7 ± 0.1 vs. 38.2 ± 0.1°C; 134 ± 9 vs. 118 ± 9°C, p < 0.05, respectively). The attenuations in FAN+WI trial did not differ to that in WI only trial (we have previously reported). Sweat rate in the chest and percentage reduction in body weight were inhibited by WI+FAN (1.3 ± 0.1 vs. 1.8 ± 0.1 mg/cm2/min; −1.6 ± 0.2 vs. −0.9 ± 0.1 %, p < 0.05, respectively), and the inhibitions were greater than in WI only trial (p < 0.05). Mean skin temperature was lower in FAN+WI trial than in the control at the end of precooling (29.0 ± 0.4 vs. 34.0 ± 0.2°C, p < 0.05) and walking (37.0 ± 0.1 vs. 37.3 ± 0.1°C, p < 0.05). Perceptions by ratings of visual analogue scale (thermal sensation and pleasantness, physical and psychological fatigues, thirst, and damp sensation) were lower in WI+FAN trial than in the control trial (p < 0.05). The attenuation in the rating score of thirst has not been seen in WI only trial.

These results suggest that combined precooling of fanning and hands and feet water immersion can inhibit dehydration and thirst more compared to each cooling conducted alone. The lower mean body skin temperature in the combined cooling procedure may contribute to attenuation of sweating.

Support or Funding Information

KAKENHI‐25293155
A Feasibility Study Investigating Body Composition and Physical Activity Levels in Children Taking Part In the Daily Mile
Authors: Brooks Naomi E , Booth Josie N , Chesham Ross , Sweeney Emma , Mitchell Iain , Ryde Gemma , Gorely Trish , Moran Colin N
Published: November 2023

Childhood inactivity is linked to poorer physical and mental health during childhood and is associated with chronic ill‐health in later life. The Daily Mile (DM) is an initiative introduced in a Primary School in Scotland where the pupils walk or run ~1 mile each day. The aim of the study was to describe the physical activity (PA) and obesity levels of children taking part in the DM. Consent was obtained from parents of 259 children (184 male; 177 female). Height (m) and weight (kg) were measured to calculate BMI (weight/height2). Z scores were calculated within year group by gender. On a sub‐set of participants (n = 79), PA levels were objectively measured by accelerometers to assess amount of light, and moderate to vigorous intensity physical activity (MVPA). Data were analysed by t‐test of proportions, one‐way ANOVA and GLM‐ANOVA. For presentation, data were separated into Primary 1 – 3 (P1‐3, age ~4–7 years) and Primary 4–7 (P4‐7, age ~7–11 years). The percentage of boys and girls taking part in the DM who were categorised as obese was consistently below the Scottish Health Survey 2013 norms (Scottish norm): Boys P1‐3: 7% (13%) P4‐7 13% (17%); Girls P1‐3 8% (13%) P4‐7 13% (20%). However, all of these differences were non‐significant. Objective measurement of physical activity revealed that boys averaged 51 mins/day and girls averaged 40 mins/day of MVPA with no difference between younger (P1‐3) and older (P4‐7) pupils. UK PA Guidelines define “active” as 60+ mins MVPA/day. “Somewhat active” can be characterised as 30–59 mins MVPA/day and “low active” as < 30 mins MVPA/day. In P1‐3 Boys: 26% were active, 58% somewhat active, 16% low active; and P4‐7 Boys: 26% were active, 61% somewhat active, 13% low active. In P1‐3 Girls: 11% were active, 72% somewhat active, 17% low active; and P4‐7 Girls: 5.3% active, 68% somewhat active, 26% low active. The proportion who were “somewhat active” was significantly higher than Health Survey England (HSE, 2012) data for age 4–10 years: boys 22% and girls 28%. All differences in active (HSE: boys 51%, girls 34%), or low active (HSE: boys 28%, girls 39%) were non‐significant. Rates of obesity in a school implementing ~1 mile PA/day for over 3 years were not significantly below the Scottish average. Only 25% of boys and 9% of girls in this sample currently reach the UK PA Guidelines. In this cohort the DM appears to have more children “somewhat active” than national data. However, this data is cross sectional and further research is required to assess the effects of the intervention.
Effect of Acute Local Heating on Lower Extremity Macro‐ and Microvascular Dilator Function in Humans
Authors: Romero Steven A. , Gagnon Daniel , Cramer Matthew N. , Simmons Grant H. , Pellinger Thomas K. , Poh Paula Y.S. , Kouda Ken , Crandall Craig G.
Published: November 2023

Local heating of an extremity increases blood flow and vascular shear stress throughout the arterial vascular tree. Local heating acutely improves macrovascular dilator function in the upper extremities through a shear stress dependent mechanism. However, the effect of local heating on macro‐and microvascular dilator function of the lower extremities is unclear. Therefore, the purpose of this study was to test the hypothesis that acute local heating improves lower extremity macro‐ and microvascular dilator function. Five healthy subjects (2 females; age 27 ± 4 years; height 166 ± 4 cm; weight 65 ± 7 kg; mean ± SD) immersed their lower extremities at a depth of ~33 cm into a circulated water bath (42.5 ± 0.4°C) for 45 min. Superficial femoral artery blood flow and diameter (Doppler ultrasound) were measured prior to and every 15 min during heating. Intestinal temperature, skin and skeletal muscle temperatures of the calf were measured. Prior to and 30 min after heating, macro‐ (flow‐mediated dilation) and microvascular (3 min reactive hyperemia area under the curve) dilator function were assessed in the superficial femoral artery following 5 min of arterial occlusion. Local heating increased superficial femoral artery blood flow (pre 63.7 ± 10.8 mL min−1 vs. 45 min local heating 606.3 ± 54.3 mL min−1) and shear rate (pre 51.5 ± 12.9 s−1 vs. 45 min local heating 410.6 ± 70.9 s−1; both P < 0.05). Intestinal temperature (Δ0.7 ± 0.1°C), calf skin temperature (Δ9.1 ± 0.1°C), and muscle temperature (Δ8.3 ± 0.6°C; all P < 0.05) increased at 45 min local heating. Macrovascular dilator function was unchanged following heating (pre 4.6 ± 1.1% vs. post 4.6 ± 0.7%; P = 0.8). Microvascular dilator function increased following local heating (pre 456 ± 89 mL vs. post 605 ± 101 mL; P = 0.02). However, after normalizing for differences in baseline blood flow, microvascular dilator function did not differ (pre 423 ± 71 mL vs. post 556 ± 91 mL; P = 0.2). Taken together, local heating of the lower extremities increases blood flow and shear rate similar to that previously observed in the upper extremities. However, these data suggest that these hemodynamic changes do not improve lower extremity macro‐ or microvascular dilator function following local heating in healthy humans.

Support or Funding Information

Funded by National Institutes of Health (GM‐068865).
Age‐ and Sex‐Related Differences in the Cutaneous Vascular Response to Exogenous Angiotensin II
Authors: Krajek Alex C , Kolb Kelsey E , Lang James A
Published: November 2023

The enzymatic machinery for the production and activation of angiotensin II (AngII) is locally expressed in human skin. Moreover, it has been demonstrated that AngII contributes to the reflex vasoconstriction (VC) response in aged skin; however, the cutaneous responsivity of AngII across a range of doses has not been examined. Thus, we hypothesized that the cutaneous VC response will incrementally increase with higher doses of Ang II. Additionally, we hypothesized that AngII‐mediated VC will be affected by the inhibition of adrenoreceptor or angiotensin II type II receptor (AT2R) pathways. Three microdialysis (MD) fibers were placed in the forearm skin of 8 young (Y: 23 ± 1 year) and 8 older (O: 68 ± 1 year) individuals for administration of 1) lactated Ringer's solution (control), 2) adrenoreceptor blockade with 5mM yohimbine + 1 mM propranolol (Y+P), and 3) AT2R inhibition with 1 μM PD‐123319 (PD). Then, AngII was added to the perfusates at eight graded dose concentrations, ranging from 0.1 nM to 1 mM, administered at 10 min intervals. Laser Doppler flux (LDF) was measured for each MD site and cutaneous vascular conductance (CVC) was calculated as CVC = LDF/mean arterial pressure and was expressed as a percent change from baseline (%ΔCVC). Compared to the control site (Y = 31 ± 6, O = 36 ± 5 %ΔCVC), the peak VC response at the highest dose was attenuated at the Y+P site (Y = 20 ± 5%, O = 32 ± 6 %ΔCVC) but was elevated at the PD site (Y = 42 ± 10, O = 41 ± 5 %ΔCVC). Furthermore, older women (44 ± 5 %ΔCVC) exhibited a greater peak VC at the control site compared to older men (23 ± 5 %ΔCVC; p < 0.05). These results indicate that older women have greater vasoconstrictor sensitivity to exogenous AngII than young individuals or older men. These data further suggest that AngII may be affecting multiple targets, including adrenergic and AT2R pathways.

Support or Funding Information

DMU IOER Grant 05‐13‐05
Bicarbonate Infusion Attenuates Arterial Desaturation During Maximal Exercise
Authors: Volianitis Stefanos , Bredmose Per P , Nielsen Henning B , Strømstad Morten , Quistorff Bjørn , Secher Niels H
Published: November 2023

Maximal exercise is associated with a reduced O2 saturation of arterial haemoglobin (SaO2). We evaluated the effect of pH in the reduction of SaO2 during maximal exercise by attenuating the metabolic acidosis with intravenous administration of bicarbonate. Eight competitive oarsmen (age 22.5 ± 3 yr, body weight 78 ± 2 kg, and height 1.83 ± 0.05 m; mean ± SD) performed 2000 m maximal ergometer row in random order either with sodium bicarbonate (Bicarb, 100 to 325 ml; 1 mM) or an equal volume of 0.9% saline (Sal). Arterial blood samples were obtained at rest and immediately after exercise. During the Sal trial arterial pH was reduced to 7.12 ± 0.01, while during Bicarb acidosis was attenuated in a dose related manner (7.29 ± 0.03; P<0.05). Lactate concentration during Bicarb was higher than Sal (26 ± 3 vs. 20 ± 1 mM; P<0.05). Also, bicarbonate concentration and SaO2 were higher (20.5 ± 1.8 mM vs 11.8 ± 0.8 mM and 92.5 ± 1% vs 89.4 ± 1%; P<0.05) during Bicarb compared to Sal, respectively. Arterial O2 partial pressure decreased similarly during the two trials (82.5 ± 2.6 vs. 87.3 ± 2.1 mmHg). The results demonstrate that during maximal exercise the decrease in SaO2 is influenced not only by the limited pulmonary diffusion capacity but also by the attenuated O2 affinity for hemoglobin induced by the decrease of plasma pH (Bohr effect).

Support or Funding Information

Dr. Per Bredmose received a grant from The Købmand i Odense Johann og Hanne Weimann f. Seedorfs foundation.
Novel cystine transporter in renal proximal tubule identified as a “missing partner” of cystinuria‐related membrane protein rBAT/SLC3A1
Authors: Nagamori Shushi , Wiriyasermkul Pattama , Nakagomi Saya , Okuyama Hirohisa , Okuda Suguru , Ohgaki Ryuichi Ohgaki , Kanai Yoshikatsu
Published: November 2023

Heteromeric amino acid transporter (HAT) family is one of the major amino acid transporter families responsible for cellular uptake and epithelial transport. HATs form heterodimers composed of a 12 membrane spanning light chain (SLC7) that catalyzes transport functions and a single membrane spanning heavy chain (SLC3) essential for plasma membrane localization and stabilization of the light chains. Among HAT family, the heterodimer of b0,+AT/SLC7A9 and its auxiliary subunit rBAT/SLC3A1 is responsible for cystine reabsorption in renal proximal tubules. The mutations in either subunits cause cystinuria, an inherited aminoaciduria with impaired renal reabsorption of cystine and dibasic amino acids. However, an unsolved paradox is that rBAT is highly expressed in S3 segment, the late proximal tubules, whereas b0,+AT expression is the highest in S1 segment, the early proximal tubules. Therefore, the presence of unknown partner of rBAT in S3 segment has been proposed. In this study, by means of co‐immunoprecipitation followed by mass spectrometry, we have found that AGT1/SLC7A13 is the missing partner of rBAT. AGT1 is localized in the apical membrane of S3 segment, where it forms a heterodimer with rBAT. Proteoliposomes reconstituted purified AGT1‐rBAT heterodimer transported cystine, aspartate and glutamate. In the apical membrane of the S3 segment, AGT1 is suggested to locate itself in close proximity to sodium‐dependent acidic amino acid transporter EAAC1 for efficient functional coupling. EAAC1 is proposed to take up aspartate and glutamate released into luminal fluid by AGT1 due to its countertransport so that preventing the urinary loss of aspartate and glutamate. Taken all together, AGT1 is the long‐postulated second cystine transporter in S3 segment of proximal tubules and a candidate to be involved in isolated cystinuria.

Support or Funding Information

This work was supported in part by Grants‐in‐Aid for Scientific Research on Priority Areas of “Transportsome” (to Y.K.) and Innovative Areas “HD Physiology” (to S. Nagamori) from the Ministry of Education, Culture, Sports, Science and Technology of Japan; Grants‐in‐Aid for Scientific Research (to Y.K. and S. Nagamori) from the Japan Society for the Promotion of Science.
Tricyclic antidepressants as inhibitors of the multidrug transporter, human OCT2: Influence of structural similarity to inhibitory efficacy
Authors: Terpstra Jennifer , Wright Stephen H
Published: November 2023

Organic cation transporter 2 (OCT2) mediates the initial step in renal secretion of organic cations, which comprise approximately 40% of currently prescribed drugs. Due to its potential as a target for unwanted drug‐drug interactions (DDIs), much attention has been directed toward understanding the basis of OCT2 selectivity. These studies typically assess selectivity based on inhibition profiles for OCT2‐mediated transport of a probe substrate produced by a structurally diverse range of test inhibitors. Here we assessed the profile of OCT2 inhibition produced by 9 structurally similar inhibitors, i.e., a set of tricyclic antidepressants (TCAs). Structural similarity was assessed by Tanimoto coefficients, which ranged from 0.5 to 0.83. As the measure of transport activity we determined uptake of a fluorescent substrate, N,N,N‐trimethyl‐2‐[methyl(7‐nitrobenzo[c][l,2,5]oxadiazol‐4‐yl)amino]ethanaminium iodide (NBD‐MTMA) into cells stably expressing OCT2. Uptake was effectively linear for 5 min, and the Jmax and apparent Kt values for NBD‐MTMA were 25 ± 5.2 pmol cm−2 min−1, and 11.7 ± 5.7 μM, respectively. Despite the structural similarity of the test inhibitors, IC50 values varied by up to 100 fold, from as low as 0.2 ± 0.02 to 0.4 ± 0.03 μM (Amitriptyline and Doxepin), to 2.1 ± 0.07 to 3.1 ± 0.05 μM (for Imipramine and Protriptyline), to as large as 20.2 ± 4.14 to 27.7 ± 1.8 μM (for Chlorpromazine and Butriptyline). There was no correlation between degree of similarity (based on Tanimoto coefficients) and pairwise comparison of IC50 values for all the TCAs tested. The comparatively high affinity of OCT2 for Amitriptyline and Doxepin, combined with reported unbound Cmax levels, resulted in Cmaxub/IC50 ratios that exceed 0.1, highlighting them as potential perpetrators of unwanted DDIs. These data show that similarity of structure is not a good criterion for predicting inhibitory interaction with OCT2.

Support or Funding Information

NIH grant 5R01DK58251
Carboxylesterase 1 Protects Against Liver Injury and Is Regulated by Hepatocyte Nuclear Factor 4α
Authors: Xu Jiesi , Xu Yang , Zhang Yanqiao
Published: November 2023

Alcoholic liver disease (ALD) is a leading cause of alcohol‐related mortality worldwide. Liver cirrhosis is the 12th leading cause of death in the US, with a total of 36,427 deaths in 2013, 49.8% of which are related to alcohol. So far, the mechanism underlying the pathogenesis of ALD is not fully understood. In addition, pharmacological interventions for ALD remain limited and less effective. In the present study, we show that both hepatocyte nuclear factor a (HNF4α) and carboxylesterase 1 (CES1) are markedly reduced in patients with alcoholic steatohepatitis. Alcohol represses both HNF4α and CES1 expression in primary hepatocytes. We further show that HNF4α controls CES1 expression by directly binding to the proximal promoter of CES1. Global inactivation of CES1 causes alcohol‐ or methionine and choline deficient (MCD) diet‐induced liver inflammation, likely as a result of elevated levels of hepatic acetaldehyde, reactive oxygen species and mitochondrial dysfunctions. Knockdown of hepatic CES1 causes ethanol‐induced steatohepatitis. Our data indicate that the HNF4α‐CES1 pathway plays a crucial role in protection against the pathogenesis of ALD. Targeting hepatic CES1 may be a plausible strategy for treatment of ALD.
The Effect of Maternal Separation and Early Environmental Enrichment on the Rat Colon
Authors: Colón‐Echevarría Claudia , Cruz Myrella L , Doreste Raura , Torres‐Reveron Annelyn , Appleyard Caroline B
Published: November 2023

Background

Early life stress has been associated with increasing the risk of developing gastrointestinal disorders by disrupting the brain‐gut axis function. Maternal separation (MS) in rats is a well‐studied model of early life stress and has been linked to inflammation in adulthood in conditions such as inflammatory bowel disease and irritable bowel syndrome. Environmental enrichment (EE) has been hypothesized to prevent the damaging effects of stress exposure by stabilizing the hypothalamic‐pituitary‐adrenal axis but there is no timeframe yet established to pinpoint when this treatment is more effective.

Aim

Investigate whether maternal separation causes intestinal inflammation and whether early environmental enrichment can reverse any alterations.

Methods

Sprague‐Dawley rat pups (both male and female, n=4–6/treatment group/gender) were separated from the mother for 3 hours/day from postnatal day one until 21 days of age. Rats were kept in either standard housing or environmental enrichment boxes, until postnatal day 78 when forced swim and open field‐testing were performed before sacrifice. Colon tissues were removed and paraffin embedded, after which microscopic scoring, crypt length and mast cell counts were evaluated.

Results

MS caused an increase in microscopic colon damage compared to normal controls (not exposed to MS or EE) in both females (p<0.05) and males (p<0.001). MS animals also had longer crypt length and increased mast cells. Males showed greater damage than female rats after MS protocol and EE, however enriched males showed a decrease in depressive‐like behaviors while enrichment did not have any effect in females. The early environmental enrichment did not reverse the damage caused in maternally separated rats but tended to decrease mast cell infiltration.

Conclusion

MS caused inflammation in the colonic tissue, which was not attenuated by early EE. Damage to the mucosal barrier by MS may be due to loss of tight junction proteins. Future studies need to be performed to evaluate the effect of later environmental enrichment on MS rats.

Support or Funding Information

Supported in part by R25GM082406, K07AT008027, and MD007579.
Changes in Gastric Myoelectrical Activity in Response to Selected Cranial Osteopathic Manipulations in Healthy Young Individuals
Authors: Ioudina Marina , Toder Eric , Samra Parneet , Kaldawi Sami
Published: November 2023

Osteopathic manipulations in the cranial field (cranial manipulation, CM) are a part of osteopathic manipulative treatment and are commonly used to treat patients. It is suggested that CM affects the autonomic nervous system. We hypothesized that CM may have an effect on the digestive system and have conducted this study to measure gastric electrical activity in response to selected CM using non‐invasive cutaneous electrogastrography (EGG). Healthy 25–35 year old men and women participated in this study. All CM were performed by one osteopathic physician and data were recorded and analyzed using BIOPAC Systems, Inc. equipment and software. CM effectiveness was evaluated based on the changes in the amplitude of the EGG in the frequency range that is associated with gastric slow waves.

Our preliminary results indicate that CM appears to decrease the amplitude of the EGG. These data suggest that selected cranial manipulations may affect gastric motility.

Support or Funding Information

This project was funded by the TUN Research Grant Award.
PERFORMANCE IN GROSS ANATOMY AND IDENTIFICATION OF STUDENTS NEEDING ASSISTANCE/GUIDANCE IN LEARNING
Authors: Zill Sasha
Published: November 2023

Goal

The goal of this study is to improve teaching of Gross Anatomy to first year medical students and enhance performance on Step 1 Board Examinations by utilizing questions on Anatomy written examinations as a metric for early identification of students needing assistance/guidance in learning.

Methods

The data base was derived from tests given to first year medical students as part of training in a required course in Gross Anatomy. Multiple choice questions (written by the investigator) were part of written examinations given in different body regions. The specific questions were in the areas of: General Introduction to the Nervous System; Anatomy of the Lower Extremity; Anatomy of Head and Neck. Student scores on specific questions were analyzed from records kept by investigator. Data on class performance in subsequent Step 1 Board Examinations were derived from reports generated by our school.

Results

Comparison of the mean scores on written examinations in Gross Anatomy showed no clear relationship with subsequent performance of the classes on Step 1 National Board Examinations. However, there was a significant correlation between the number of students having difficulty with Gross Anatomy and subsequent board exam performance (P = <0.0001, Student's T test).

Discussion

The results to date indicate that performance on questions in Gross Anatomy examinations may be a useful metric in identifying students that may require assistance in learning body structure and medical terminology. The lack of correlation of overall performance in Gross Anatomy and Board exams could readily reflect the decrease in the number questions that directly test anatomical knowledge. However, it is important note that the mean performance of classes on the Gross Anatomy examinations was quite high and the many questions were asked repeatedly with no attempt to make them more discriminative. The specific causes of difficulties encountered by some students are unclear but may reflect their academic background and extent of training in Anatomy prior to entrance into medical school. Overall, these results suggest that analysis of questions in Gross Anatomy may be of considerable utility in early identification students and remediation of students that have difficulty in the basic core of knowledge and language of medicine.
Skeletal Muscle PPARδ Increases Acutely with Resistance Exercise Inversely Proportional to Body Fat Percentage
Authors: Chen Vincent CW , Lee Chang Woock , Bui Steve , Lee Teak V , Riechman Steven E
Published: November 2023

Purpose

PPARδ expression in skeletal muscle has been shown to increase in response to resistance exercise training in our laboratory. However, it is unclear whether PPARδ expression is affected by a single bout of resistance exercise. Since dyslipidemia is associated with excess body fat, we examined the relationship between the change of PPARδ content and percent body fat in response to one bout of whole body resistance exercise.

Methods

Eleven untrained young men (N=4) and women (N=7) performed one bout of whole body resistance exercise that included leg press and leg extension for emphasis on quadriceps femoris muscles. Body fat percentage was measured by DEXA before exercise. Muscle biopsies were performed on the vastus lateralis muscles 24 hours before and 24 hours after the exercise. Western Blotting was conducted to quantify the PPARδ content.

Results

With body fat percentage as a covariate, PPARδ levels increased by 49.1% (p<0.001) after one bout of resistance exercise. The amount of changes in PPARδ was inversely proportional to the body fat percentage (R2=0.769, P=0.001).

Conclusion

Our data suggest that when adjusted for body fat percentage, resistance exercise may acutely increase PPARδ content, which may be a key factor of lipid metabolism.

Support or Funding Information

1. The Sydney & J.L. Huffines Institute for Sports Medicine & Human Performance 2. American College of Sports Medicine‐ Texas Chapter (TACSM) 3. Department of Health and Kinesiology, Texas A&M University 4. College of Education and Human Development, Texas A&M University
Age Dependent Changes in Muscle Expression of Enzymes Effecting The Production of Testosterone and Dihydrotestosterone in Young and Old Mice and the C2C12 Cell Line
Authors: Pearson Tim , Powell Penny
Published: November 2023

Background

Sarcopenia is a debilitating condition that exhibits a progressive decline in skeletal muscle mass and function with age. Sarcopenia can lead to an increased susceptibility to falls and can result in the loss of independent living. Despite this, the causes and mechanism(s) underlying sarcopenia are not fully understood.

Methods

Young (3 month) and aged (>22 month) male mouse extensor digitorum longus (edl; a fast‐twitch muscle), soleus (a slow‐twitch muscle), and anterior tibialis muscle bundles were rapidly isolated and subsequently prepared for use in western blotting. The expression of enzymes influencing testosterone (T) and dihydrotestosterone (DHT) production were investigated in the different age groups, with similar protein targets being investigated in C2C12 myoblast and myotube cells after treatments with either DHT (5nM) or T (30nM).

Results

Overall, all muscles investigated showed more pronounced expression of 5α‐reductase‐2 than that of 5α‐reductase‐1, both of which generate DHT from T, irrespective of age. Both reductases were more abundant in aged muscles, irrespective of muscle type except that of the anterior tibialis for reductase‐2 which was reduced with age. We report androgen receptor expression in myoblasts that increased significantly with exposure to DHT or T, whereas the expression of the androgen receptor in myotubes was only weakly detectable. In response to the DHT or T treatments, myoblast expression of; aromatase, 5α‐reductase‐1/2, 17‐β‐hydroxysteroid dehydrogenase, Myo‐D, Pax7 and the amino acid transporters SNAT2 and LAT2 were unchanged. Interestingly myotubes showed increased expression upon exposure to DHT or T of Myo‐D and trends to increased expression of 5α‐reductase‐2 and SNAT2 with no change in Pax7, aromatase, 17‐β‐hydroxysteroid dehydrogenase or LAT2.

Conclusion

From these results we suggest that a component of sarcopenia may arise from an age‐dependent reduction of the DHT or T dependant anabolic stimulus. We also suggest that muscles such as the soleus and edl attempt to resist this reduction in androgens by locally generating DHT by enhancing expression of 5α‐reductase enzymes. A possible mechanism of action to DHT exposure may involve active satellite cells and the increased expression of SNAT2 to then modify amino acid transport into muscle, where both of these may influence positively muscle viability.

Support or Funding Information

Funded by the BBSRC.
Measuring Damaged Area is More Reliable than Counting Damaged Myofibers in Cross Sections of Injured Skeletal Muscle
Authors: Abro Valerie M , Begam Morium , Roche Joseph A
Published: November 2023

BACKGROUND

Histological studies of dystrophic and/or injured skeletal muscle, often involve quantifying the extent of myofiber damage. Our laboratory's current standard operating procedure is to count damaged and intact fibers in a cross section, and express myofiber damage as (Damaged Fibers/Total Fibers) X 100. However, it can be difficult to estimate the number of fibers in a region where myofiber boundaries have been obliterated due to extensive tissue damage. We therefore compared the inter‐rater reliability between an expert and a novice, for quantifying myofiber damage, based on counting damaged myofibers or measuring damaged area. We hypothesized that measuring damaged area has a higher inter‐rater reliability than counting damaged myofibers.

METHODS

Five unique digital images (Zeiss Axio Scope.A1 LED FL‐LED microscope, 20X objective) were analyzed by a novice (2 weeks of experience) and an expert (13 years of experience) with Image J software. Images were of cross sections of injured mdx mouse skeletal muscle, stained with fluorescently‐labeled antibodies to mouse IgG, since IgG entry is a marker of myofiber damage. Counts of IgG‐positive (IgG+) fibers and measurements of IgG+ areas were compared for intra‐rater reliability, and data from each method were compared between novice and expert for inter‐rater reliability.

RESULTS

The Pearson's Correlation Coefficients (R scores) for intra‐rater reliability between IgG+ fibers Vs IgG+ area were 0.9934 for novice and 0.9437 for expert (R = 0.9626 for novice and expert combined). The inter‐rater reliability between novice and expert was higher for IgG+ area than for IgG+ fibers (R = 0.9845 and 0.9275, respectively).

DISCUSSION AND CONCLUSION

While assessing myofiber damage histologically, measuring damaged area is more reliable than counting damaged myofibers. Moreover, measuring damaged area can be performed in about 25% of the time than counting individual damaged and intact myofibers.

Support or Funding Information

Supported by a Faculty Startup Package to JAR from Wayne State University, and a grant to JAR from the Jain Foundation Inc.
Electrical Stimulation Mimics Endurance Exercise‐induced Autophagy in Skeletal Muscle
Authors: JANG YONGCHUL , KWON INSU , LANNING SARAH , SPRINGER CHARLES , LAGGAN BRETT T , COSIO‐LIMA LUDMILA , LEE YOUNGIL
Published: November 2023

Autophagy, a cellular recycling process, plays a crucial role in maintenance of cellular function, and has emerged as a potential therapeutic strategy in chronic adult diseases such as diabetes and cancer. While muscle contraction by endurance exercise is known to cause autophagy, whether muscle contraction induced by electrical stimulation (ESTIM) can mimic an exercise effect remains unknown. Here we showed that four weeks of ESTIM (40 min/day, four days/week) upregulate autophagy flux. Four healthy female subjects, aged 18–24 years participated in the study. Prior to and post ESTIM, muscle samples were collected by a needle biopsy from quadriceps of dominant (control) and non‐dominant legs (experiment), onto which ESTIM was applied, respectively. Our data demonstrated that ESTIM significantly increased autophagic flux as evidenced by an increase in the ratio of LC3II to LC3I and LC3II levels, as well as a decline in P62 levels. Intriguingly, ESTIM‐mediated autophagy coincided with Beclin‐1 and Atg7 downregulation, whereas upregulation of BNIP3, a strong autophagy promoter ensued in response to ETIM compared to untreated muscles. Also, HSP70 reported to be a lysosome function enhancer arose by ESTIM. We assessed if ESTIM results in mitochondrial biogenesis and observed that, despite a significant decline in levels of PGC‐1α and NFR‐1, ESTIM exhibited enhanced levels of mitochondrial complex II (SDHB) in parallel with a mitochondrial transcription factor, TFAM. Taken together, our results suggest for the first time that chronic ESTIM induces autophagy in the absence of upregulation of Beclin1 and Atg7, but in the presence of BNIP3. Furthermore, ESTIM may be an important therapeutic approach that can imitate an exercise effect with regard to mitochondrial biogenesis.

Support or Funding Information

The authors gratefully acknowledge the research support for the University of West Florida Scholarly and Creative Activities Committee.
Intra Renal Bradykinin Blunted the Baroreflex Control of Renal Sympathetic Nerve Activity in Anaesthetized Rats
Authors: Akhtar Safia , Sattar Munavvar Zubaid Abdul , Rathore Hassaan Anwer , Ahmad Ashfaq , Abdullah Nor Azizan , John Edward James
Published: November 2023

There is evidence that bradykinin (BK) results in increased afferent renal nerve activity (ARNA) which leads to sympathetic over activity. This study investigates whether bradykinin supresses high and low‐pressure baroreceptor regulation of renal sympathetic nerve activity (RSNA) in rats. Rats were anaesthetized by means of the administration of 1 mL (i.p.) of a chloralose–urethane mixture (16.5 and 250 mg mL−1 respectively). BK or saline were infused into the cortico‐medullary border of the ipsilateral kidney and RSNA recordings were made from the contralateral (left) kidney. Baroreflex gain curves for RSNA were generated by increasing and decreasing blood pressure using i.v. doses of phenylephrine and sodium nitroprusside (50 μg in a volume of 0.2 mL for each) while the low‐pressure or cardiopulmonary receptors were stimulated by infusing an acute saline volume load for 30 mins. Intrarenal infusion of BK reduced high pressure baroreflex sensitivity for RSNA by 32% (P < 0.05) compared with that of saline infused animals. Volume expansion resulted in greater renal sympatho‐inhibition by 43% (P < 0.05) in rats with saline infusion, whereas BK infused rats shows non‐significant renal sympatho‐inhibition by 12%. Intrarenal infusion of BK causes dysregulation of the arterial and cardiopulmonary baroreflexes. These findings reveal a significant role of the inflammatory mediator, BK which would blunt the normal cardiovascular homeostasis and can contribute to a deranged autonomic control.

Support or Funding Information

The authors fully acknowledge the Universiti Sains Malaysia Research Undergraduate (USM‐RU) grant (1001/PFARMASI/815078) provided by Universiti Sains Malaysia, Malaysia.Safia Akhtar is a recipient of a USM Fellowship [P‐FD0091/11(R)] from the Institute of Post‐Graduate Studies (IPS), Universiti Sains Malaysia (USM), Penang, Malaysia
A Novel Role of AT1a Receptors in The Proximal Tubules of The Kidney in Renal Ischemia‐Reperfusion Injury in Mice
Authors: Zhang Jianfeng , Li Xiao C , Zhuo Jia L
Published: November 2023

It is well recognized that the renin‐angiotensin system via angiotensin II (ANG II) plays an important role in the pathogenesis of renal ischemia‐reperfusion injury, but the mechanisms involved remain incompletely understood. The present study used global (Agtr1a−/−or AT1a‐KO) and conditional proximal tubule‐specific AT1a‐KO (PT‐AT1a‐KO) mouse models to test the hypothesis that deletion of AT1a receptors globally or selectively in the proximal tubules of the kidney attenuates renal ischemia‐reperfusion injury. Three groups (n=6–8/per group) of adult male C57BL/6J (WT), AT1a‐KO, and PT‐AT1a‐KO mice were subjected to sham surgery or bilateral kidney ischemia for 40 min, followed by reperfusion recovery for 7 days. Basal systolic blood pressure (SBP) was 25 ± 3 mmHg lower in AT1a‐KO mice (p<0.01) and 13 ± 3 mmHg lower in PT‐AT1a‐KO mice, respectively, than in WT mice (p<0.05). 7 days after renal ischemia‐reperfusion, there were no differences in SBP, 24 h urine and urinary sodium excretory responses in all strains, compared with their respective basal levels. However, kidney wt. to body wt. ratio was significantly increased in AT1a‐KO and PT‐AT1a‐KO mice (p<0.05). Renal ischemia‐reperfusion injury and recovery was assessed by Masson Trichrome staining and compared between WT, AT1a‐KO and PT‐AT1a‐KO mice. No significant glomerular, tubulointerstital, and peri‐vascular fibrotic responses were observed in sham controls of all strains. However, significant fibrotic responses were observed in the glomeruli, cortical tubulointerstitial and peri‐vascular tissues in WT mice 7 days after renal ischemia reperfusion injury (p<0.01). Unexpectedly, glomerular, tubulointerstital, and peri‐vascular fibrotic responses to renal ischemia reperfusion injury were significantly worsen, rather than attenuated, in global AT1a‐KO mice (p<0.01). By contrast, deletion of AT1a receptors selectively in the proximal tubules markedly attenuated glomerular, tubulointerstital, and peri‐vascular fibrotic responses in PT‐AT1a‐KO mice 7 days after renal ischemia‐reperfusion injury (p<0.01). These results indicate that AT1a receptors in the proximal tubules of the kidney play an important role in renal ischemia‐reperfusion injury, and that deletion or blockade of AT1a receptors in the proximal tubules may attenuate renal ischemia‐reperfusion injury.

Support or Funding Information

This work was supported in part by grants from NIDDK & NIGMS (2R01DK067299 & 1R01DK102429) to Dr. Zhuo.
Chronic amphetamine exposure causes long‐term effects on dopamine uptake
Authors: Ferdous Nafisa , McCowan Talus J , Carvelli Lucia
Published: November 2023

The dopamine transporter (DAT) is a plasma membrane transporter that clears released dopamine from the synaptic cleft; therefore it is an important regulator of extracellular levels of dopamine. DAT is also the main molecular target of many drugs of abuse, most notably the psychostimulants cocaine and amphetamine. Amphetamine (AMPH) is a substrate of DAT and competes for reuptake with dopamine. Several groups have shown that acute AMPH treatments alter the function and the number of DAT on the cell membrane. However, no data is available regarding the long‐term effects of AMPH on DAT activity. Data collected in our laboratory suggest that parental AMPH exposure affects dopamine uptake in C. elegans dopaminergic neurons isolated from progeny. These results led us to hypothesize that reduced dopamine reuptake in subsequent generations, as a result of parental AMPH exposure, is caused by down‐regulation of DAT. In order to overcome the complexity of multicellular organisms and the challenges of primary cell isolation and culture, where very few cells differentiate into dopaminergic neurons, we investigated the long‐term effects caused by AMPH in simplified systems. Initial experiments were carried out in LLC‐PK1 cells, stably transfected with human DAT. Cells were pre‐exposed to AMPH for 15 hours and uptake assays, carried out after cells had doubled, showed a significant decrease in dopamine uptake compared to control (untreated cells). These data suggest that changes caused by AMPH were maintained after one cell cycle. We repeated the same experiment using the human neuroblastoma SH‐SY5Y cells which can be differentiated into authentic dopaminergic neurons. Prior to the uptake assay one group of undifferentiated SH‐SY5Y cells was exposed to AMPH for 15 hours and the other group was treated with control solution. The cells were then allowed to grow and cross generations before they were treated with Retinoic Acid (RA) to induce differentiation. Uptake assays carried out 5 days after RA initiated differentiation revealed a significant decrease in dopamine uptake in AMPH treated groups with respect to control. These results suggest that parental AMPH pretreatment down regulates the expression or activity of DAT. We are currently investigating whether chronic exposure to AMPH in progenitor cells alters DAT expression in daughter cells.

Support or Funding Information

COBRE P20 GM104360
Fumarate Regulates Hif1α, Superoxide, and Matrix in Zebrafish and Mouse Models of Diabetic Kidney Disease
Authors: You Young‐Hyun , Liu Chao , Huang Wei , Miller Yury I , Sharma Kumar
Published: November 2023

We have recently found that fumarate, a TCA cycle metabolite, is increased in early type 1 diabetes and may play a key pathogenic role in enhancing matrix accumulation and stimulation of Hif1α, key features of diabetic kidney disease (DKD). Administration of a single IP injection of fumarate to non‐diabetic BL6 mice induced TGF‐β, SMAD3 and fibronectin in mice kidney cortex as compared with PBS‐injected control. Fumarate exposure to HEK293 cells led to an increase in HIF1α and TGF‐β expression, along with stimulation of collagen I, fibronectin, and α‐SMA. The role of fumarate was further explored in a zebrafish model of acute hyperglycemia. We found that 2% and 3% high glucose exposure for 24–48h decreased superoxide production in the pronephros of larval zebrafish, as measured by OX‐DHE fluorescence. A 2–3% glucose treatment also leads to a significant reduction in the expression of a zebrafish ortholog of the fumarate hydratase gene (fh) and protein. Exposure of zebrafish to 7.5–10 uM fumarate for 24h led to reduction of superoxide production and an increase in Hif1α and Collagen1a1a expression in zebrafish larvae. In conclusion, similar to what we previously observed in diabetic mice, fumarate enhances matrix stimulation and reduces superoxide production, possibly, via Hif1α activation in zebrafish. Taken together, our findings demonstrated that fumarate regulation has an important role in the development of DKD and may constitute a therapeutic target for the management of DKD.

Support or Funding Information

This work was supported by grants from NIH to K.S..