bluuebunny/crossref_metadata_2025 huggingface dataset:
Rosuvastatin therapy for dyslipidemia and other associated parameters in Saudi metabolic syndrome patients
Authors: Rafeeq Misbahuddin , Habib Hamed , Murad Hussam , Gari Mamdouh , Gazzaz Zohair
Published: November 2023

Background

Metabolic syndrome (MS) is a constellation of metabolic irregularities comprising dyslipidemia, hypertension, hyperglycemia, chronic inflammatory, and hypercoagulable state predisposing to diabetes and cardiovascular events. Statins are first‐line drugs to treat the associated atherogenic dyslipidemia.

Aim

Effect of rosuvastatin on dyslipidemia and other abnormalities of MS in Saudi patients was studied.

Settings and Design

Prospective, open label, randomized clinical study.

Materials and Methods

Patients of either sex ≥18 years (n = 153) having MS as per modified National Cholesterol Education Program Adult Treatment Panel III criteria were prescribed rosuvastatin 10 mg OD for 24 weeks. Serum lipids, biochemical, clinical, and anthropometric parameters were studied before and after treatment.

Statistical Analysis Used

Statistical Package for Social Sciences version17 was used. Descriptive analysis was used for all variables and documented as mean ± SD. Normality checked by Shapiro–Wilk test, Kurtosis and Skewness Z‐score, and visualization of histograms. Lipid levels and other parameters before and after treatment were evaluated by paired t‐test for parametric data and Wilcoxon signed rank test for nonparametric data. Pretreatment and posttreatment values were correlated by Pearson's correlation coefficient. Multiple regression analysis was performed to see effect of other variables.

Results

142 patients completed the study. Highly significant reduction was observed in LDL‐C, TC, TG, VLDL‐C, non‐HDL‐C, Lipoprotein(a) and atherosclerotic index with an elevation in HDL‐C. A total of 86% patients reached LDL‐C goal of ≤ 100 mg/dL. Beneficial response was observed on other associated parameters. There was strong correlation between pre‐treatment and post‐treatment values. No significant effect of age, gender, BMI, obesity and baseline cholesterol was observed on mean cholesterol reduction. No serious/severe adverse effects were reported.

Conclusion

Rosuvastatin markedly improved atherogenic dyslipidemia of MS besides beneficial effects on other abnormalities.

Support or Funding Information

This paper contains the results and findings of a research project that is funded by king Abdulaziz city for science and technology (KACST) (Grant no. ARP‐34‐129)
Contribution of Beta‐Arrestin Signaling on Thyroid Hormone‐Induced Cardiac Hypertrophy
Authors: Lino Caroline Antunes , Barreto‐Chaves Maria Luiza Morais
Published: November 2023

Thyroid hormones (T3) exert multiple effects on cardiovascular system. It is well known that hyperthyroidism promotes the activation of cardiac Renin Angiotensin System and previous studies have described the involvement of Angiotensin II Receptor Type I (AT1R) in T3‐induced cardiac hypertrophy. AT1R is a seven‐transmembrane domain receptor that promotes signaling transduction by G protein‐dependent and independent mechanisms. G‐protein independent mechanisms are mediated by multifunctional proteins called beta‐arrestins (βARRs), which bind and activate ERK, a classic hypertrophic signaling pathway. Herein, we evaluate the contribution of βARR signaling on ERK activation in cardiac hypertrophy induced by T3. All animal experimentation was conducted in accordance with the Ethical Principles in Animal Research set forth Brazilian College of Animal Experimentation and approved by the Institute of Biomedical Sciences of the University of Sao Paulo. Primary cultures of neonatal ventricular cardiomyocytes obtained from Wistar rats (1–3 days) were stimulated with 15nM T3 (Sigma‐Aldrich; USA). T3‐stimulated cardiomyocytes presented an increase on ERK phosphorylation at 5, 10 and 15 minutes of treatment. The inhibition of AT1R using Losartan (1uM; Sigma‐Aldrich; USA) was able to attenuate such activation, demonstrating the contribution of this receptor. The pre‐treatment with a selective inhibitor of ERK, PD98059 (20uM; Sigma‐Aldrich; USA) evidenced the involvement of this signaling in the increase of hypertrophic markers in T3‐stimulated cells. The contribution of βARRs on ERK activation promoted by T3 is still being evaluated. Besides that, the contribution of βARRs isoforms in the increase of mRNA expression levels of skeletal muscle α‐actin was demonstrated by interfering RNA assays, showing the possible contribution of βARRs signaling to hypertrophy. Our results evidence the involvement of AT1R on ERK activation and the contribution of this signaling pathway on T3‐induced cardiac hypertrophy.

Support or Funding Information

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP 2013/16142‐9 and 2016/13896‐0).
Peripheral Vascular Adaptations to All‐Extremity Aerobic Exercise Training in Healthy Older Adults
Authors: Lim Jisok , Kim Han‐Kyul , Hwang Chueh‐Lung , Yoo Jeung‐Ki , Hwang Moon‐Hyon , Handberg Eileen M , Nichols Wilmer W , Christou Demetra D
Published: November 2023

Aging is associated with arterial remodeling and dysfunction which predispose older adults to increased risk for cardiovascular disease (CVD). Although aerobic exercise training is associated with decreased risk for CVD, the optimal exercise training regimen to induce vascular adaptations in older adults is unknown. In older adults, there is some evidence that aerobic exercise improves vascular function in the exercising limbs, but not in the non‐exercising limbs, suggesting that all‐extremity exercise might be advantageous in the aged population. The purpose of this study was to compare, in older adults, the effect of all‐extremity high‐intensity interval training (HIIT) vs. moderate‐intensity continuous training (MICT) on arterial structure and function in the exercising arms and legs. Thirty‐six sedentary adults (55 to 76 yrs of age, 64±1 yrs; mean±SE), free of major clinical disease, were randomized to HIIT (n=13), MICT (n=12), or non‐exercise control group (CONT; n=11). HIIT and MICT were performed on a non‐weight‐bearing all‐extremity ergometer (Airdyne, Schwinn) on 4 days/week for 8 weeks under supervision. HIIT consisted of 40 min of 4×4 min intervals at 90% of peak heart rate (HRpeak) interspersed by 3 min bouts at 70% of HRpeak, while MICT consisted of 47 min at 70% of HRpeak. At pre‐ and post‐intervention, limb pulse wave velocity (PWV) was assessed in the arm (brachial to radial artery) and leg (femoral to posterior tibial artery; Doppler flowmeters), and arterial compliance (ultrasonography and applanation tonometry), intima‐medial thickness (IMT; ultrasonography) and blood flow (Doppler) were assessed at the brachial and common femoral arteries. Blood flow significantly increased after HIIT, but not MICT, in the femoral artery (HIIT: 546.5±58.4 vs. 769.2±88.8 ml/min, P<0.01; MICT: 669.1±48.9 vs. 733.6±44.4 ml/min, CONT: 683.7±95.7 vs. 703.3±76 ml/min, P≥0.3; pre‐ vs. post‐intervention) while in the brachial artery blood flow remained unchanged (HIIT: 112.3±16.8 vs. 105.8±13.6 ml/min, MICT: 127.1±18.2 vs. 108.7±14.3 ml/min, CONT: 109.3±17.3 vs. 114.5±22.3 ml/min, P≥0.2). Arm and leg PWV, and brachial and femoral artery compliance and IMT were not influenced by the intervention (P≥0.9). In conclusion, 8 weeks of all‐extremity HIIT, but not MICT, improved femoral, but not brachial, blood flow in previously sedentary older adults.
Mono(2‐ethylhexyl)phthalate Exposure Alters Electrical Restitution Curve in Isolated Hearts
Authors: Jaimes Rafael , Sherman Meredith , Siegel Bryan , Posnack Nikki
Published: November 2023

Medical devices are frequently manufactured with polyvinyl chloride (PVC) plastic, in combination with phthalate plasticizers to impart flexibility to otherwise rigid PVC. Since phthalate plasticizers are not covalently bound, these chemicals migrate out of the plastic device and into lipophilic solutions, including blood, parenteral nutrition, and pharmacological agents. As an example, Di(2‐ethylhexyl) phthalate (DEHP) can make up to 80% by weight of flexible medical devices, including: blood storage bags, medical tubing, and cardiopulmonary bypass and ECMO circuitry. Phthalate leaching from these devices presents a significant intravenous route of exposure to patient populations. Our previously published in vitro studies have indicated that phthalate plasticizer exposure inhibits electrical conduction in isolated cardiac cells.

Objective

To investigate the impact of phthalate plasticizer exposure on electrical restitution in isolated whole hearts.

Methods

All animal protocols were approved by the Children's National Institutional Animal Care and Use Committee. Adult rat hearts were excised, the aorta cannulated, and transferred to a Langendorff‐perfusion system. Hearts were perfused with oxygenated Krebs‐Heinslett buffer, and electrodes were placed on the epicardial surface. Mechanical contraction was inhibited with 5 uM Blebbistatin, and hearts were loaded with 200 nM RH237 to optically map action potentials. Hearts were subjected to a ventricular pacing protocol, and action potentials were recorded using an Andor iXon camera (> 500 fps). Electrical signals were collected using Iox2 software (EMKA technologies) and analyzed using custom MatLab scripts.

Results

Exposure to clinically relevant concentrations of mono(2‐ethylhexyl) phthalate (MEHP), the main metabolite of di(2‐ethylhexyl) phthalate plasticizer, resulted in a steeper monophasic electrical restitution curve (slope = 1.8) compared with biphasic control (slope = 2.1, plateau slope = 0.1). MEHP‐exposed hearts were also more susceptible to alternans at shorter cycle lengths, compared with control.

Conclusion

The effect of phthalate plasticizers on cardiac electrical restitution has important clinical implications. Alterations in action potential duration restitution and the presence of electrical alternans are arrhythmogenic factors. Additional studies are necessary to resolve the impact of plastic chemical contaminant exposure in patients, and the impact on cardiac function.

Support or Funding Information

This study was supported by the National Institutes of Health (R00ES023477 to NGP, UL1TR000075, KL2TR000076), Children's Research Institute: Divisions of Cardiology and Cardiac Surgery.
Beetroot Juice Enhances Functional Sympatholysis in Hypertensive Humans
Authors: Caldwell Jacob T , Sutterfield Shelbi L , Frye Jake , Ade Carl J
Published: November 2023

Functional sympatholysis (FS) is attenuated in patients diagnosed with hypertension (HTN) and hypertensive animal models alike. There is conflicting evidence, however, between human and animal models on the role of nitric oxide (NO) in determining the degree of FS. Therefore, we sought to determine if an oral dose of dietary nitrate [beetroot juice (BRJ)], which increases NO bioavailability, would increase the ability to blunt vasoconstriction in the face of increased neural outflow during hang‐grip exercise (HGE) in HTN patients. We tested the hypothesis that the decrease in vascular conductance experienced by hypertensive individuals would be attenuated when ingesting BRJ two hours prior to performing 20% maximal voluntary contraction (MVC) HGE, compared to the placebo (PL) condition. To date, five of the planned fifteen patients (1 male, 4 females) diagnosed with HTN have completed the study. Using a randomized, double‐blind, crossover design, forearm blood flow and conductance responses to reflex increases in sympathetic nerve activity evoked by a cold pressor test (CPT) at rest and during dynamic handgrip exercise were evaluated following consumption of BRJ and PL. Following familiarization, a five‐minute resting baseline was used to obtain resting forearm blood‐flow (FBF) and conductance (FVC) followed by a two‐minute CPT. To evaluate FS, HGE was performed at 20% MVC for seven minutes with CPT for the final two minutes. At the time of testing patients were taking various types of medication to treat HTN (e.g., angiotensin converting enzyme inhibitor + diuretic, β‐blocker, angiotensin II receptor blocker + diuretic). In resting conditions, mean arterial pressure (MAP) increased and FBF and FVC decreased during the CPT, but there was no difference between BJR and PL. During HGE at 20% MVC, MAP increased with the addition of CPT by ~ 20 mmHg, with no difference between BJR and PL. However, changes in FVC were blunted following dietary nitrate supplementation compared to placebo. Baseline MAP (BRJ: 104.7±4.4 mmHg) (PL: 104.3±4.5 mmHg) effect size (ES)= 0.04. Baseline FBF (BRJ: 55.6±3.8 ml/min−1) (PL: 88.0±17.4 ml/min−1) ES=0.92. Steady state (SS) MAP (BRJ: 121.8±3.4 mmHg) (PL: 121.0±4.1 mmHg) ES=0.09. MAP during CPT (BRJ: 126.7±2.3 mmHg) (PL: 126.7±5.3 mmHg) ES=0.09. SS HGE vascular conductance (BRJ: 229.0±24.9 ml/mmHg−1) (PL: 235.2±28.4 ml/mmHg1) ES=0.04. SS vascular conductance during HGE+CPT (BRJ: 228.9±21.1 ml/mmHg−1) (PL: 222.0±28.0 ml/mmHg1) ES=0.10. ΔFVC (BRJ: −2.5±5.51%) (PL: −15.1±3.8 %) ES=1.0. The data from this study provide preliminary evidence that indicates dietary nitrates via BRJ may enhance FS in hypertensive humans during small muscle mass exercise in the face of increased neural outflow via CPT.
Lipopolysaccharide increases the expression level of the aquaporin‐4 water channel
Authors: Sugimoto Naotoshi , Nishimura Naoki , Ohnishi Norikazu , Matsumoto Takaaki , Kitaura Takashi , Shido Osamu , Yachie Akihiro
Published: November 2023

Edema often occurs during an infection or inflammation due to the increase of tissue water permeability. The water permeability of cells is defined by the expression levels of aquaporins that are present in the plasma membrane. In this study, we investigated whether lipopolysaccharide (LPS), used to induce inflammation experimentally, alters the expression level of aquaporins in several cells.

Primaryglial cells and C2C12 myoblast cells were maintained in Dulbecco's modified Eagle'smedium (DMEM) containing 10% fetal bovine serum (FBS) at 37°C in a 5% CO2incubator. These cells were treated with LPS (10 μg/ml) for 20 min or 36 h, andthen cell lysates were harvested. The phosphorylated NF‐κB, cyclooxygenase‐2 (COX2), and aquaporin 4 (AQP4) expression levels in the cell lysates were analyzed by western blot using phospho‐specific NF‐κB,COX2, and AQP4 antibodies, respectively.

LPS exposure led to the phosphorylation of NF‐κB in both glial cells and myoblast cells after 20 min of stimulation. LPS also increased the expression levels of COX2 and AQP4 in both glial and myoblast cells after 36 h of stimulation. An NF‐κB inhibitor attenuates LPS‐induced phosphorylation of NF‐κB, COX2, and AQP4 expressions in cells.

These results suggest that NF‐κB signaling plays an important role in the inflammatory response, including the regulation of COX2 and AQP4 expression. It is possible that overexpression of AQP4 results in a rapid and increased influx of osmotic water across the plasma membrane into cells, thereby inducing cells welling and edema.
Intron 5 of RUNX1 Gene Harbor a Putative Promoter Region.
Authors: Gutierrez Soraya , Hinojosa Marcela , Schnake Nicolas , Martinez Milka
Published: November 2023

The t(8:21) is one of the most frequent chromosomal translocation found in leukemia. To date all the break points mapped for this translocation, are located in intron 5 of RUNX1 gene. Interestingly, this intron exhibit structural chromatin elements like Topoisomerase II and DNase I hypersensitive sites, which have been wildly associated to presence of transcriptional cis regulatory elements. Therefore, we hypothesize that regulatory elements are harbored in intron5 of the RUNX1 gene. In order to test this hypothesis, we performed bioinformatics analysis of ChIPseq data available from the ENCODE database to identify regions of intron 5 enriched in epigenetics marks characteristic of regulatory elements. Our results shown that in hematopoietic cells there is one region highly enrich in K4H3me, K4H3me3 and K27H3ac that colocalizes with DNase I hypersensitive sites. These marks have been associated with promoters modules. Indeed, when we cloned this region in the pGL3 basic reporter vector, we found that it activates expression of the reporter gene luciferase in an orientation dependent manner. Using ETS databases we have assemble a putative messenger for this promoter. Moreover, by RT‐PCR we have shown that this RNA is expressed both in Jurkat and HL60 cells. Taken together our results demonstrate the presence of a putative promoter region located in intron 5 of RUNX1 gene that is active in hematopoietic cells.

Support or Funding Information

FONDECYT 1130697
Mechanisms underlying hPMSC‐based protection on human brain endothelial cells
Authors: Barzegar Mansoureh , Minagar Alireza , Wang Yuping , Yun Jungmi W , Boyer Christen , Couraud Pierre‐Olivier , Alexander J.Steven
Published: November 2023

Stroke remains among the leading causes of neurologically‐based morbidity and long‐term disability and results from thromboembolism (85% of strokes) or hemorrhage (15%). Several events lead to neuronal death in the stroke‐affected brain. Initially, production of local pro‐inflammatory mediators following brain ischemia/reperfusion promote stroke injury by decreasing blood‐brain barrier and by enhancing leukocyte binding and infiltration.

Stem cell‐based therapies are a revolutionary treatment for several neurodegenerative diseases including stroke acting through neuronal cell trans‐differentiation but also provide acute protection properties by releasing substances which suppress inflammation, induce angiogenesis, and regulate vascular reactivity.

We hypothesized that human placental‐derived mesenchymal stem cells (hPMSCs), a type of extraembryonic stem cell, might enhance acute protection against injury by releasing mediators which suppress the immune cell infiltration and maintain blood brain barrier.

To investigate this, we examined the extent to which hPMSC conditioned media (CM) could mobilize junctional barrier‐creating proteins in human brain endothelial cells (hCMEC‐D3). We performed FITC‐Dextran permeability assays as well as junctional protein western blotting to evaluate the expression of junctional protein following treatment with hPMSC‐CM. We have also assessed the influence of hPMSC‐CM on contractility of human brain vascular smooth muscle cell (hBVSMC) using collagen gel contraction assay. Finally, we have used Matrigel Basement Membrane Matrix to follow up the formation of tubes from hCMEC‐D3 following treatment hPMSC‐CM. We found that passage four hPMSC‐CM improved the barrier function of hCMEC‐D3 and increased the expression of ZO‐1 and a‐Claudin‐1 proteins involved in tight junction. We also observed less contraction of hBVSMC treated with hPMSC‐CM. Moreover, hPMSC‐CM could accelerate the tube formation of hCMEC‐D3.

We conclude that PMSC release stable factors which beneficially and acutely influence barrier structure and integrity. Therefore, PMSC may affect both acute as well as chronic phases of recovery in stroke.
Exploiting Delta Cell Paracrine Interactions to Curb Glucagon Hypersecretion in Diabetes
Authors: Noguchi Glyn M , Donaldson Cynthia J , Mawla Alex M , Saghatelian Alan , Huising Mark O
Published: November 2023

Diabetes is first and foremost a disease of insulin impairment, but is often accompanied by aberrant glucagon secretion. Uncontrolled alpha cell activity leads to further complications such as diabetic hyperglycemia, and we currently lack good options to manage this aspect of the disease. Within healthy pancreatic islets, delta cells exert an inhibitory influence over the alpha and beta cells via somatostatin; thus, they are uniquely positioned as the principal source of local inhibitory control preventing hormone signaling from going awry. Recent studies from our lab and others have identified local signals (such as Urocortin3 from the beta cells) and external factors (such as ghrelin from the GI tract) that act to directly stimulate somatostatin secretion. These observations cast delta cells as central hubs that are essential to maintain homeostatic control of insulin and glucagon. The objective of this study is to test if the negative feedback from pancreatic delta cells can be targeted to restore control over excess glucagon release in diabetes.

Methods

We have combined transcriptomics, chemicogenetics, and functional imaging of alpha, beta and delta cells in intact islets to help showcase the role of the delta cell within the islet.

Results

Our results indicate that Urocortin3 transiently silences alpha cell activity by activating delta cell‐dependent negative feedback.

Conclusion

By targeting the delta cells, we can take advantage of the local feedback mechanism and restore inhibition of alpha cells. Our findings suggest that the pancreatic delta cell is a viable target to normalize the excess glucagon secretion that is partially responsible for hyperglycemia in diabetes.

Support or Funding Information

Glyn Noguchi is supported by a NIGMS‐funded Pharmacology Training Program (T32GM099608). The Huising Lab is funded by awards from the Juvenile Diabetes Research Foundation (JDRF) and a Hartwell Individual Biomedical Research Award.
The Effect of the Endocrine Disrupting Chemical Bisphenol A on Pro‐opiomelanocortin, Circadian Rhythm and Neuroinflammatory Marker Gene Expression in Hypothalamic Cell Models
Authors: Salehi Ashkan , Belsham Denise D.
Published: November 2023

Obesity is a global health crisis that has doubled in prevalence since 1980 and is associated with co‐morbidities, such as type 2 diabetes mellitus and circadian rhythm disruption. Therefore, understanding the cellular mechanisms responsible for obesity has relevance for improving human health. A number of endocrine‐disrupting chemicals, such as bisphenol A (BPA), an industrial chemical present in 95% of human urine samples, have been linked to obesity. However, the effect of BPA on the pro‐opiomelanocortin (POMC) neurons of the hypothalamus has yet to be explored. POMC neurons produce a precursor polypeptide that is cleaved into the anorexigenic peptide MSH, known to inhibit feeding behaviour. Altering POMC expression could therefore disrupt energy homeostasis in the hypothalamus, ultimately leading to weight gain. We hypothesized that BPA induces a neuroinflammatory response to alter the gene expression of POMC, thereby impairing feeding regulation. We also hypothesized that BPA may alter the expression of circadian clock genes. This study utilized two characterized hypothalamic neuronal models, the adult‐derived mHypoA‐POMC/GFP‐2 and embryonic mHypoE‐43/5 cell‐lines. Both cell‐lines were chosen for their expression of inflammatory markers, circadian genes and POMC transcripts. We examined the effect of 100 M BPA on the transcription of POMC, pro‐inflammatory genes IL6, NFκB, IκB, and the endoplasmic reticulum (ER) stress marker CHOP, over a 24 h timecourse by real‐time quantitative PCR (RT‐qPCR). Analysis of circadian clock genes Bmal1, Per2 and Rev‐Erb was also undertaken. In the mHypoA‐POMC/GFP‐2 cell‐line, BPA significantly upregulated POMC, IL6, IκB and CHOP mRNA levels. Furthermore, BPA significantly altered the mRNA levels of Bmal1 and Per2 at specific time points, indicating a disruption of the circadian clock. Similar to the adult‐derived POMC line, BPA significantly altered the mRNA levels of POMC, IL6, IκB, NFκB and CHOP, Bmal1, Rev‐Erb and Per2 in the mHypoE‐43/5 cell‐line. Given the altered expression of feeding‐related peptides, BPA could have an inflammation‐mediated mechanism of action that is being explored. Additionally, the disruption of circadian genes by BPA could further alter cellular function necessary for proper energy homeostasis. In ongoing studies, we are employing anti‐inflammatory compounds to determine whether induction of inflammation causes POMC and circadian gene expression disruption. In conclusion, our study is the first to explore the direct effects of BPA on POMC neuronal cell models, demonstrating altered expression of genes associated with obesity. We therefore have the necessary tools to understand this process at a more mechanistic level.

Support or Funding Information

This research was supported by grants from the CIHR.
The Role of Androgens in the Exercise Induced Decrease in Protein Breakdown
Authors: Rossetti Michael L , Gordon Bradley S
Published: November 2023

Androgens play an important role in the regulation of muscle protein balance. The decrease in androgen production and/or bioavailability observed in various atrophic conditions is associated with increased rates of muscle protein breakdown in the fasted metabolic state. While the increase in muscle protein breakdown is accompanied by a decrease in oxidative capacity, the contribution of muscle oxidative capacity to muscle protein breakdown in the absence of androgens is unclear. To shed light on this, male mice that were 10 weeks of age were subjected to a sham or castration surgery. Ten days post‐surgery, mice from both groups were further randomized to remain sedentary or perform aerobic treadmill exercise (6 days a week for 8 weeks) to increase oxidative capacity. At the conclusion of the 8‐week training, mice underwent a run to fatigue to assess training effectiveness. Mice were fasted overnight prior to sacrifice to induce a fasted metabolic state. All mice subjected to the training ran significantly longer compared to the sedentary groups with no effect of castration observed. Plantaris muscle mass was significantly higher in sham exercised mice compared to the castration exercised group. While exercise training increased expression of the mitochondrial protein, cytochrome c oxidase subunit IV (COX IV), in both sham and castration conditions, this measure was significantly lower in castrated mice relative to sham values. Interestingly, exercise training decreased the LC3 II/I ratio, a marker of autophagy activation, only in sham mice which could not be explained by corresponding changes in putative autophagy regulatory factors. However, a strong inverse relationship between COX IV and the LC3 II/I ratio was observed, suggesting that muscle oxidative capacity contributed to the change in autophagy activation. In all, these data support a role of muscle oxidative capacity in the androgen‐mediated regulation of autophagy activation during the fasted metabolic state.

Support or Funding Information

UCF Office of Research and Commercialization Grant to Bradley Gordon
Chronic and Acute Effects of Hot Water Immersion on Strength, Recovery and Hypertrophy
Authors: Peake Jonathan , McGorm Hamish , Roberts Llion , Coombes Jeff , Cameron‐Smith David , Raastad Truls
Published: November 2023

Research demonstrates heat therapy is effective for enhancing acute post‐exercise recovery, and increasing training adaptation. However, evidence from studies representing real‐world training practices is sparse. Effects of regular hot water immersion (HWI) on adaptations to resistance training are yet to be investigated. The aim of this study was to determine if HWI enhances resistance training adaptations. Recreationally active participants (n=16) were matched for strength and assigned to HWI or passive recovery (PAS) groups. Participants completed 10 weeks of lower‐body hypertrophy resistance training, 2 days a week. Ten minutes of HWI (45°C) or PAS was performed after each training session. Strength data (1 RM) for leg press (LP), knee extension (KE) and knee flexion (KF); muscle mass analysis by dual x‐ray absorptiometry (DXA) and magnetic resonance imaging (MRI)) were measured pre‐and post‐training. Muscle biopsies were collected immediately before the last training session, and at 2, 24 and 48 hours after the end of the recovery session following the last training session. Both groups increased (p < 0.001 to 0.030) their strength for all three exercises. Absolute DXA muscle mass (HWI; 1.8% and 2.4%, and PAS 4.6% and 5.5%) increased (p < 0.001 to 0.006 in both groups) for leg and gynoid regions, respectively. Absolute MRI quadriceps muscle mass also increased (HWI; p = 0.013, 6.2%; PAS p = 0.000, 10.1%). However, the relative increase in DXA leg muscle mass was significantly less after HWI compared with PAS (p = 0.011, 2.1‐fold). PCR analysis revealed significant time effects for changes in gene expression of IL‐1beta and LIF in both groups, significant time effects for IL‐6 and Ccxl2 in the PAS group, and significant time effects for CD163 in the HWI group. No time effects were found for HSP90, TNF‐α, CCl4, CD11b, CD68 or CD206 mRNA expression. No significant differences between groups were noted for any gene. Regular HWI does not seem to enhance strength adaptation to resistance training, and may actually attenuate gains in muscle mass. HWI does not enhance post‐exercise recovery through heat shock protein, cytokine or macrophage response. Analysis on the effects of HWI on myogenic regulatory factors and mTOR kinases is ongoing.
The Influence of CYP1A2 Genotype on Caffeine Consumption Habits and Athletic Performance Enhancement in Collegiate Distance Runners
Authors: Ye Jiayu Jennifer , Nagy Erzsebet Emily , Millard Julie T.
Published: November 2023

The liver enzyme CYP1A2, which is responsible for metabolizing caffeine, is a member of the cytochrome P450 family. CYP1A2 activity is highly variable across individuals, depending on factors such as gender, personal habits (e.g., smoking status and diet), and genotype. A single nucleotide polymorphism (A/C) in intron 1 of the CYP1A2 gene leads to differences in gene inducibility, with AA individuals reportedly having higher activity than C‐allele carriers. Several reports have suggested that genotype can modulate the physiological effects of caffeine. For example, “fast metabolizers” with the AA genotype benefit more from caffeine supplementation before cycling time trials than C‐allele carriers. We investigated whether CYP1A2 genotype influences self‐reported caffeine consumption and performance effects in collegiate distance runners. DNA samples and questionnaires were collected from 65 subjects. PRC‐RFLP was performed to determine genotype. Preliminary statistical analysis based on the questionnaires indicates that there was no significant difference in self‐reported daily caffeine consumption and degree of performance enhancement between the AA homozygotes and C‐allele carriers, suggesting that environmental factors may modulate gene effects of CYP1A2.

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 P20GM0103423.
Evidence for Direct Interactions between RNA Polymerase and Ribosomes.
Authors: Blaha Gregor M , Fan Haitian , Conn Adam B , Diggs Stephen , Hahm Joseph , Williams Preston B , Wang Yinsheng
Published: November 2023

Transcription and translation are coupled in prokaryotes. Coupling originates from close proximity of the RNA polymerase and the ribosome due to their concurrent binding to the same nascent RNA. A similar proximity between RNA polymerase and the ribosome occurs during ribosome biogenesis; when ribosome assembly ensues while the rRNA is being transcribed. Here we report the existence of direct physical interactions between RNA polymerase core enzyme and vacant ribosome in the absence of mediating factors. The interactions appear to be of ionic nature and persist in the presence of an excess of BSA, RNA, or phosphate. The binding of ribosomes to RNA polymerases saturates at a one to one stoichiometry, while that of RNA polymerase to ribosomes saturates at a two to one. The dissociation constant of these complexes is within the physiological concentration range of free RNA polymerase and ribosomes. When bound to ribosomes, the RNA polymerase adopts a conformation similar to that under high salt which appears to be distinct from that of the transcription elongation complex and holoenzyme. Thermus thermophilus RNA polymerase and ribosomes can form complexes with each other as well as mixed‐species complexes with E coli RNA polymerase and ribosomes. Our results suggest that the interface between RNA polymerase and ribosome is conserved and coordinates the interactions between RNA polymerase and ribosome during transcription‐translation coupling and/or during ribosome biogenesis.

Support or Funding Information

UCR collaborative seed grant
Ammonium Conductance in a Mouse Thick Ascending Limb Cell Line
Authors: Lee Soojung , Park Jonathan , Choi Inyeong
Published: November 2023

NH4+ is a key buffer component that regulates blood pH. The kidneys excrete NH4+ to urine as they produce HCO3−, and the mechanism by which NH4+ excretion results in net acid excretion involves a series of sophisticated NH4+ transport processes in different parts of the nephron. One of the nephron segments that play key roles in NH4+ excretion is the thick ascending limb (TAL). In the luminal membrane of the TAL tubules, the Na/K/2Cl cotransporter is the major fraction of the active NH4+ flux. Nonetheless, in vitro studies reveal that K/NH4 exchange and NH4+ conductance, whose molecular identities are presently unknown, can contribute to the TAL NH4+ transport by 35–50%. The two pathways exhibit biophysical and pharmacological characteristics that distinguish them from other NH4+‐transporting proteins. Despite such physiological and functional significance, our understanding of these pathways is limited. Especially, the electrophysiological properties of the NH4+ conductance have been unknown.

In this study, we examined the NH4+conductance in the TAL cell line ST‐1 to determine its basic electrophysiological properties such as the amounts of NH4+current produced in cells, current‐voltage (I–V) relationship, and reversal potential of the current. Whole cell patch clamp was performed to measure the current evoked by NH4Cl in the presence of BaCl2, tetraethylammonium and BAPTA. Application of 20 mM NH4Cl induced an inward current with mean amplitude of −272 ± 79 pA (n = 9). In I–V relationships, NH4Cl application caused the I–V curve to shift down in an inward direction. The difference in curves before and after NH4Cl application, which corresponds to the NH4Cl‐mediated currents at different voltages, was progressively larger at more negative potentials. The reversal potential was +15 mV, more positive than a calculated equilibrium potential for Cl−, thus indicating that the current is not due to Cl−but to NH +. We then expressed ST‐1 total proteins in Xenopus oocytes and performed two‐electrode voltage clamp. Application of NH4Cl in the presence of BaCl2 caused the I–V curve to be steeper in an inward direction. Interestingly, removing Na+ from the bath solution caused the NH4+ conductance to disappear. Na+removal additionally led to a partial reduction of endogenous oocyte conductance, which was abolished by bumetanide. At pH 6.4, the NH4+conductance was still produced while endogenous oocyte conductance was not detected. In conclusion, we, for the first time, report the electrophysiological properties of the NH4+conductance in the ST‐1 cells. This conductance is Na+‐dependent, different from the previously reported Cl−‐dependent NH4+conductance in isolated TAL tubules.

Support or Funding Information

This work was supported by the Emory physiology department bridge fund to I.C.
Experimental oxidative stress‐induced death of erythrocytes
Authors: Senchenkova Elena Y. , Skvertchinskaya Elisaveta , Dobrylko Irina , Sudnitsyna Julia , Gambaryan Stephan , Mindukshev Igor , Gavins Felicity
Published: November 2023

Background

Excessive erythrocyte (red blood cells, RBCs) hemolysis is observed in different pathological states including sepsis, sickle cell disease and diabetes. Prior to senescence RBCs undergoing membrane injury due to reactive oxygen species (ROS) possess a damaged membrane coupled with impaired function and increased hemolysis. Oxidative stress plays a major role in alteration of membrane integrity and fragility of RBCs causing a functional propensity of erythrocytes to flow into microcirculatory vascular beds where erythocytes can adhere to endothelial monolayers and hemolyse. The mechanisms of oxidative stress‐induced death of RBCs relate to Ca2+‐influx and caspase activation coupled with an increase in apoptotic markers, such as cell shrinkage, membrane blebbing, leading to phosphatidylserine (PS) exposure and hemoglobin oxidation.

Objective

To understand the mechanisms by which ROS promotes dysfunction of RBC membrane integrity and RBC cell death.

Methods

Flow cytometry, confocal microscopy, spectroscopic and lazer partical analysis techniques were appled to assess osmotic fragility of RBCs, cell morphology, apoptotic markers (esterase activity, Band 3 clasterization, caspase 3 activation, PS externalization), and hemoglobin oxidation state (methemoglobin (MetHb) and hemichrom (FeIII)).

Results

Ca2+‐influx (A23187) is associated with decreased cell volumes, PS externalization and increased cell rigidity. Influx of Ca2+ resulted in no changes in either hemoglobin oxidation state (oxyHb~95%), band 3 clustering or caspase 3 activation.

Tert butyl hydroperoxide (tBHP) administration caused a dose‐dependent alteration of membrane integrity and fragility of RBCs. High dose of tBHP (>3 mM) resulted in a robust decrease in cell volume without cell membrane transformations. tBHP administration at 0.5–2mM mediated an alteration of membrane deformatility of RBCs, along with an initial increase in cell volume, hemolobin oxidation with increased MetHb and FeIII formation, caspase 3 activation, band 3 clustering, PS externalization, and formation of microparticles. These membrane alterations are Ca‐independent processes.

NO (S‐nitrosocysteine, SNC) causes increased MetHb formation associated with no changes in membrane structures.

Conclusion

Our results illustrate that oxidative stress induces RBCs death associated with an increase in apoptotic markers (caspase 3 activation, PS exposure, formation of microparticles) which is, Ca‐independent and results in FeIII binding to band 3, band 3 clustering, erythrocyte membrane vesiculation, and oxidized haemoglobin containing microparticles.
Role of the Free Fatty Acid 4 Receptor in Endothelial Cell Responses to Oleic Acid
Authors: Rogers Kelsey , Davis Danielle , Kurjiaka David
Published: November 2023

The impact of fatty acids on the vasculature is a complicated story: some appear to have pro‐inflammatory effects (trans and saturated) whereas others have anti‐inflammatory effects (cis and omega 3). The discovery of a G protein coupled free fatty acid receptor (FFAR) has provided a potential explanation for these disparate vascular responses to fatty acids of different structures. In particular, the FFAR‐4 is activated by fatty acids that are expected to be anti‐inflammatory. Based upon the size and structure of oleic acid (18 carbon, cis fatty acid), we expect the anti‐inflammatory effects of oleic acid on the vasculature involve activation of the FFAR‐4. We tested the hypothesis that oleic acid binds to the FFAR‐4 receptor to reduce the inflammatory response in vascular endothelial cells. Western blot confirmed the presence of the FFAR‐4 in bEnd.3 cells (cultured mouse endothelial cells: ATCC). After treating bEnd.3 cells for 12 hrs with 30 μM oleic acid, the expression of connexin 43 (a marker of endothelial cell damage/inflammation) was reduced (n=5). As the concentration of oleic acid was increased from 0.3 to 300 μM, connexin 43 expression decreased in a dose dependent manner (n=4). When treated with an agonist for the FFAR‐4 (5 μM TUG‐891: Tocris), bEnd.3 cell expression of connexin 43 was reduced (n=3). Thus, preliminary data are consistent with the FFAR‐4 mediating the anti‐inflammatory effects of oleic acid on endothelial cells.

Support or Funding Information

This work was funded by Grand Valley State University (Presidential Research Grant: D Davis and Student Summer Scholars: K Rogers and D Kurjiaka).
Reversing glycocalyx degradation; identification of a pharmacological target to improve endothelial function in type II diabetes
Authors: Foote Christopher A , Castorena‐Gonzalez Jorge A , Padilla Jaume , Sowers James R , Martinez‐Lemus Luis A
Published: November 2023

In diabetes, diminished production or reduced bioavailabilty of nitric oxide (NO) in the vasculature, referred to as endothelial dysfunction, is consistently observed and significantly increases the risk for the subsequent development of cardiovascular disease. We posit that, early in the pathogenesis of endothelial dysfunction, elevated levels of neuraminidase lead to the degradation of the glycocalyx and significantly impairs endothelial function as reflected by a reduction in the ability of arteries to dilate in response to sheer stress. In support of this hypothesis, we provide evidence that flow‐mediated dilation is reduced ex vivo in mouse mesenteric arteries exposed to neuraminidase, and that neuraminidase treatment reduces glycocalyx volume. Utilizing an animal model of diabetes (4‐week old male mice fed a western diet (WD) for 16 weeks) we demonstrate that serum neuraminidase activity is elevated compared to control fed animals and this is coincident with a reduced ability of femoral arteries from WD fed animals to dilate in response to Acetylcholine. We also report that both femoral and mesenteric arteries from WD fed animals have an increased modulus of elasticity, a measure of wall stiffness that is typically associated with reduced NO bioavailability in vascular beds. We propose that the inhibition of neuraminidase activity with an FDA approved viral neuraminidase inhibitor could potentially reverse endothelial dysfunction in animal models of diabetes as well as in patients with type II diabetes by reversing glycocalyx degradation and restoring the glycocalyx to its fully functional volume.

Support or Funding Information

NIH‐HL‐088105 to LAM and NIH‐HL‐107910 to JRS
Limited Activity‐Dependent Changes in NMJ Structure and Function During Aging
Authors: Barbat‐Artigas Sebastien , Robitaillle Richard
Published: November 2023

Aging has been associated with losses of muscle mass and strength, a phenomenon termed “sarcopenia”. A growing body of evidence suggests that it may originate from alterations (mostly structural fragmentation) of neuromuscular junctions (NMJs). Furthermore some evidence show that physical activity partially prevents age‐related NMJs fragmentation and muscle mass and strength losses, reinforcing the relationship between NMJs and muscle function. However, the efficacy of the NMJ, that is, the ability of the motor neuron to control the muscle fiber, has been largely overlooked. Hence, we investigated NMJ synaptic strength and plasticity, two important indicators of its function. We compared soleus muscles of active adult (12 months) and active old mice (30 months). NMJ structure was assessed by immunolabeling while synaptic properties were studied using electrophysiological recordings. Despite their activity level, soleus muscle mass was lower in older than in young mice (17.9±0.4 mg vs. 22.2±0.3, respectively, p<0.001). Endplates of NMJs of old mice were also more fragmented (6.2±0.3 vs. 1.9±0.2 fragments, p=0.0023). Furthermore, while a high frequency stimulation (60Hz, 30s) resulted in a long‐lasting potentiation in adults (4±2%), it produced a long‐term depression in old mice (−8±2%, p=0.039, 40 min post‐stimulation). However, synaptic strength (Quantal content; the amount of vesicle of neurotransmitters released during a stimulation) was preserved in old mice (3.2±0.3 vs. 3.1±0.2 in young mice, p=0.63). Results suggest that activity reduces some aspects of NMJ aging (structure and synaptic strength). However, other aspects (synaptic plasticity) remained altered, suggesting that they may be implicated in the remaining loss of muscle mass and strength in active elderly.
Neuromuscular regeneration following whole muscle transplantation
Authors: Pollock Natalie , Davis Carol S , Hassett Cheryl A , Staunton Caroline A , Vasilaki Aphrodite , Jackson Malcolm J , Brooks Susan V , McArdle Anne
Published: November 2023

Age‐related loss of muscle mass and function has been attributed to failed adaptive responses to insults experienced by the neuromuscular system with evidence of smaller, weaker muscles and disrupted neuromuscular junctions (NMJs). It has been suggested that extrinsic factors such as the environment of the host organism is likely to influence these adaptations and also regenerative processes in nerve and muscle. Previous work has used whole muscle transplants between adult and old hosts to examine the role of the environment on neuromuscular regeneration. Subsequent morphological changes in the regenerating muscle have been well documented (eg. Carlson and Faulkner 1989). However, there is limited information relating to the role of the environment on neuronal morphology following degeneration and regeneration after transplantation.

In the current work we investigated the regenerative progress of the nerve following whole muscle transplantation.

Experiments were performed in old (22–24months) and adult (4–6months) C57Bl6 mice. The distal and proximal tendons of the extensor digitorum longus (EDL) muscle were cut to free the muscle and the nerve transected. Each mouse had both EDLs removed and cross or same age transplanted. The severed motor nerve was implanted into the donor muscle and both tendons sutured onto the tendon stumps of the hosts. Following 60 days recovery, contractile properties of the muscle were measured and the tissue fixed for examination of NMJ structure. Fluorescently labelled antibodies including s100 (Schwann cells) and synaptophysin (pre‐synapse) were used to visualise the neuronal components and acetyl choline receptors (AchRs) were labelled with bungarotoxin.

In all samples a large proportion of the AchRs were localised in small dispersed loci running parallel along the skeletal muscle fibres which clearly overlapped with s100 positive cells. This pattern was especially evident in muscles from old mice transplanted into old mice. Intact AchR clusters displaying the normal “pretzel” formation were limited but were most apparent in adult to adult specimens. Although there was limited synaptic occupancy it has been suggested that even limited synaptic overlap is sufficient to cause muscle contraction.

Neuronal contact is required to begin the process of AchR clustering in the formation of NMJs. The differences seen in AchR clustered versus that seen dispersed along the muscle fibres may be indicative of the effect of environment on the nerve regenerative progress.

Support or Funding Information

Supported by the UK Biotechnology and Biological Sciences Research Council (BBSRC) and National Institutes of Health (NIH).