bluuebunny/crossref_metadata_2025 huggingface dataset:
Proximal convoluted tubule cells-derived exosomes attenuate aging-related vascular dysfunction
Authors: Kwon Youngin , Aung Lynn-Htet-Htet , Sun Zhongjie
Published: May 2024

Aging is an identified risk factor for cardiovascular disease. Aging is associated with increased prevalence of endothelial dysfunction and arterial stiffening. Exosomes are bi-lipid nanoscale vesicles that play important roles in intercellular communications. The purpose of this study was to determine whether administration of renal proximal convoluted tubule cells (PCT)-derived exosomes affects vascular and renal function in aging mice. Aging (24 months old) and young mice (3 months old) were treated with PCT-derived exosomes via non-invasive injection into the kidney 3 times a week for 2 weeks. Administration of PCT-derived exosomes did not affect blood pressure or urinary Na+, K+, and Ca2+ excretions, indicating that PCT-derived exosomes did not affect kidney function. Pulse wave velocity (PWV) was increased in aging mice, indicating arterial stiffening. Interestingly, treatment with PCT-exosomes effectively reduced aging-associated arterial stiffening. In addition, aortic endothelium-dependent relaxing (EDR) responses to acetylcholine (Ach) were reduced in aging mice, indicating endothelial dysfunction. Treatment with PCT-derived exosomes rescued aging-associated aortic endothelial dysfunction. Mechanistically, aortic expression of VCAM1, ICAM1, TNFα, and MCP-1 was upregulated in aging mice, indicating vascular inflammation. Notably, aging-associated vascular inflammation was largely attenuated by delivery of PCT-derived exosomes. Our results suggest that PCT-derived exosomes improves aging-associated arterial stiffening and vascular dysfunction partly via inhibiting vascular inflammation. The findings may help develop novel therapeutic strategies for aging-associated vascular dysfunction using PCT-derived exosomes.

This work is supported by NIH research grants R01 HL154147 and AG062375.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Lung capillary endothelium to arterial endothelium transition in pulmonary arterial hypertension
Authors: Liu Bin , Yi Dan , Xia Xiaomei , Ramirez Karina , Dong Ryan , Gao Anton , Dai Zhiyu
Published: May 2024

Pulmonary arterial hypertension (PAH) is characterized by a progressive increase of pulmonary vascular resistance and obliterative pulmonary vascular remodeling that result in right heart hypertrophy, failure, and premature death. The underlying mechanisms of loss of distal capillary endothelial cells (ECs) and obliterative vascular lesion formation remain unclear. Our recent single-cell RNA sequencing, spatial transcriptomics analysis, RNASCOPE, and immunostaining analysis showed that arterial ECs accumulation and loss of capillary ECs were evident in human PAH patients and pulmonary hypertension (PH) rodents. Pseudotime trajectory analysis of the single-cell RNA sequencing data suggest that lung capillary ECs transit to arterial ECs during the development of PH. Our study also identified CXCL12 as the marker for arterial ECs in PH. General capillary EC lineage tracing approach using Plvap-DreERT2;Tdtomato mice demonstrated that general capillary ECs gave rise to arterial ECs during PH development. Genetic deletion of HIF-2a or pharmacological inhibition of Notch4 normalized the arterial programming in PH. In conclusion, our study demonstrates that general capillary endothelium transits to arterial endothelium through the HIF-2a-Notch4 pathway during the development of PAH. Thus, targeting arterial EC transition might be a novel approach for treating PAH patients.

This work was supported in part by NIH grant R00HL138278, R01HL158596, R01HL62794, R01HL169509, R01HL170096, AHA Career Development Award 20CDA35310084, The Cardiovascular Research and Education Foundation, Arizona Biomedical Research Centre funding (RFGA2022-01-06), and University of Arizona institution funding to Z.D.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
IF1 Knockout Protects Against Doxorubicin-Induced Cardiac Dysfunction by Improving Cardiomyocyte Energetics
Authors: Mobasheran Parnia , Donovan Meagan , Yang Qinglin
Published: May 2024

Doxorubicin (DOX), a member of the Anthracycline antibiotics class, has been used as a potent chemotherapy agent against solid tumors. However, its use is limited by its cardiotoxicity. It is well-documented that mitochondrial dysfunction is one of the main mechanisms of DOX-induced cardiotoxicity. ATP synthase inhibitory subunit 1 (ATPIF1, or IF1) is an endogenous inhibitor of mitochondrial ATP synthase. Recent studies indicate that IF1 may suppress mitochondrial respiration via inhibiting ATP synthase. Others and our previous studies demonstrated that IF1 inactivation exerts hepatic and cardiac protective effects. We hypothesize that the absence of IF1 protects the heart from DOX-induced cardiotoxicity by improving mitochondrial energy metabolism. We first investigate the impact of IF1 KO on mitochondrial respiration using the high-resolution respirometer (OROBOROS) on freshly isolated cardiac mitochondria from IF1 KO and WT mice. IF1 KO mitochondria did show substantially increased state 2, state 3, and state 4 respiration rates compared with those of WT. We then investigated if WT and IF1 KO mice respond differently to DOX treatment. WT and IF1 KO mice at the ages of 12-16 weeks either received DOX 3mg/kg/every other day or vehicle intraperitoneally for two weeks. In vivo, cardiac function was evaluated using the VEVO F2 Echocardiographic system (Visual Sonic) 4 and 6 weeks after initiation of DOX and vehicle administration. Compared with the vehicle-treated WT mice, left ventricular ejection fraction (LVEF) was substantially decreased in DOX-treated WT mice compared with vehicle-treated WT mice. In contrast, LVEF in DOX-IF1 KO mice was substantially less reduced compared with vehicle-treated IF1 KO mice. We next investigated if improving cellular energetics is the critical mechanism underlying the protective effects of IF1 KO. Mouse neonatal cardiomyocyte (NMCM) isolated from WT and IF1 KO mice were cultured and treated with 0.5 and 1mM Dox for 24 hours. Cellular energetics were measured with the Mito stress assay using the Seahorse Bioanalyzer (96Xpro, Agilent). Basal, maximal, and ATP production-linked oxygen consumption rates were markedly decreased in DOX-treated-NMCM but not in DOX-treated IF1 KO NMCM compared with Vehicle-treated NMCM. In summary, the above in vivo and in vitro investigations support that IF1 inactivation is protective against DOX cardiac toxicity, at least partly, via improving cellular energetics; therefore, inactivating IF1 may be a potential therapeutic target to prevent and mitigate DOX-induced cardiomyopathy in patients.

This research was supported by project number 5R01HL160969 from the National Heart Lung and Blood Institute at the NIH.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Diaphragm Force and Mitochondrial Function Following Enhanced Nitric Oxide Availability During Mechanical Ventilation
Authors: Pierce Simon , Cannon Daniel , Nogueira Leonardo
Published: May 2024

During mechanical ventilation (MV), force developed by the diaphragm decreases over time much faster than locomotor muscles, known as ventilator-induced diaphragm dysfunction (VIDD). VIDD is accompanied by an increase in intramyofiber protein S-nitrosylation, a modification of cysteines by nitric oxide (NO). During the treatment of acute respiratory distress syndrome (ARDS), inhaled NO is commonly used to improve gas exchange, but little is known about the effects of increased NO availability to the diaphragm during MV and the intracellular mechanisms to protect against excessive S-nitrosylation. We hypothesize that the enzyme S-nitrosoglutathione reductase (GSNOR) protects against excessive protein S-nitrosylation in diaphragm myofibers in conditions where NO availability is enhanced during MV, thereby preserving contractile function. We tested this hypothesis by enhancing NO availability and blocking GSNOR activity in mice during MV. Mice were treated with GSNOR inhibitor (SPL-334; GSNORi) or both GSNORi and NO donor isosorbide dinitrate (GSNORi-ISDN) together, and mechanically ventilated for 2h. E x vivo diaphragm force and mitochondrial respiration were measured. Male (C57BL/6J) 3-4 month old mice (n=27) were anesthetized and subjected to MV for 0 (non-MV), 2, 4, or 6h (150 breaths/min, 10 cmH2O PIP, 3.5 cmH2O PEEP. 8 mL/kg VT). Alternatively, mice were treated with PBS/10% DMSO (DMSO, n=6) or 25 μg SPL-334 in PBS/DMSO (GSNORi, n=6) or 25 μg SPL-334 + 1.7 mg ISDN in PBS/DMSO (GSNORi-ISDN; n=6), and then subjected to MV for 2 h. After MV, mice were euthanized, and diaphragm strips were used for force, and permeabilized fiber bundles for mitochondrial oxidative phosphorylation and H2O2 generation measurements. Peak tetanic force was decreased by MV ~23% at 4 h and ~40% at 6 h (P=0.0183 and P=0.0062, respectively, one-way ANOVA, Tukey post-test) vs 0 h. However, peak force was not different between DMSO, GSNORi and GSNORi-ISDN at 2 h MV. Coupled-phosphorylating mitochondrial respiration (Kruskal-Wallis H=2.2, p=0.35) was not different but H2O2 flux was highest in GSNORi-ISDN vs DMSO and GSNORi (Kruskal-Wallis H=6.6, p=0.03). GSNORi and ISDN treatment during MV did not produce any changes to VIDD and to mitochondrial respiration, but increased ROS production. If exogenous NO is not provided, inhibiting GSNOR in vivo alone does not affect diaphragm function ex vivo during short MV.

Support: TRDRP (T32IR5221 and T29KT0397CA, to L.N.) and SDSU 2023 SEED Grant (to L.N.).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Effect of a Probiotic on Anxiety/Depression through the Gut-Brain Axis
Authors: Skelton Michele , Walker Christopher
Published: May 2024

The purpose of this study was to determine whether probiotic supplementation can display a positive effect on depressive or anxious measurements/symptoms. The bedrock of this project is whether a nexus exists between microbiome quality and robustness of mental health. Twenty-three individuals were ultimately included in the analysis with 11 in the placebo group and 12 in the probiotic group. Subjects ingested four capsules at the same time once a day at approximately the same time of day; this regimen endured for four weeks. Individuals completed the GIQLI before and after supplementation to gauge (mental) health quality. Both the probiotic and placebo groups experienced improvements in their mental health scores, though the difference between pre and post scores for the probiotic group was significant (p≤0.05). Current evidence suggests probiotics can serve as a beneficial remedy for emotional symptoms.

Stetson University.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Proteomic profiling points to the significance of adipocyte-derived extracellular vesicles in diet-induced obesity
Authors: Zhao Yuying , Guo Deng-Fu , Rahmouni Kamal
Published: May 2024

Extracellular vesicles (EVs) are lipid-bilayer membrane-enclosed vesicles well known to mediate cell-cell communication to maintain normal physiological functions. The diverse cargo of EVs encompassing proteins, lipids and miRNAs represent potential biomarkers and therapeutic targets. However, the role of adipocyte-derived EVs (AdEVs) in obesity is still unknown. To address this, we performed proteomic profiling of AdEVs isolated from the C57BL/6 male mice that were fed either a normal chow diet (NCD) or a high-fat high-sucrose diet (HFHSD) for 12 weeks starting at 4 weeks of age. AdEVs were obtained, through ultracentrifugation, from the conditioned media of cultured adipocytes derived from gonadal adipose tissue. Nanoparticle tracking analysis (NTA) of AdEVs showed that adipocytes from mice fed HFHSD tended to release more AdEVs despite the comparable size of AdEVs relative to those of mice fed NCD. Subsequently, proteins were isolated, digested and labeled with TMTpro16-plex for proteomic analysis. Raw data were processed in Scaffold, and a general bioinformatic and functional analysis conducted in Ingenuity Pathway Analysis Qiagen (IPA) ( https://digitalinsights.qiagen.com/explore/ga-ipa?utm_source=QDI_GA_SA_IPA_1122_PF&cmpid=QDI_GA_IPA ) and Srplot identified over 1100 proteins in AdEVs (protein threshold: 99%, minim peptide:2, peptide threshold: 95%, 0.00% FDR). Of these, 58 proteins were identified as upregulated while 41 proteins were downregulated in HFHSD-fed mice (Fold Change > 2, adjusted p < 0.05). With IPA analysis, the top 3 influenced pathways including mitochondrial dysfunction (27%), Sirtuin signaling pathway (22%), and Granzyme A signaling (38%) are predicted to be activated while the oxidative phosphorylation (47%), estrogen receptor signaling (15%) and neutrophil extracellular trap signaling pathway (14%) are predicted to be inhibited. The Gene Oncology (GO) functional enrichment analysis in Srplot revealed the involvement of identified differentially expressed proteins in various biological processes such as lipid metabolism, catabolic process processes, and cellular respiration. Experiments are underway to validate specific proteins involved in these biological processes. Furthermore, analysis of cellular components highlighted three notable terms including myelin sheath, collagen-containing extracellular matrix and organelle inner membrane. In conclusion, the present study elucidates the significance of AdEVs in the context of diet-induced obesity and underscores the potential role of mitochondrial dysfunction in the initiation and progression of obesity and its associated diseases.

NIH Veterans Affairs.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Effects of Long-lasting Volleyball Training on Tubulointerstitial Damage in Adolescent Female Athletes
Authors: Yasuda Nobuo
Published: May 2024

In adolescent female athletes, monitoring physical condition using non-invasive methods such as urine could speed the provision of information to athletes and coaches, thereby preventing injuries and promoting improved performance. On this matter, it has been reported that physical stress is cumulatively increased by prolonged training in adolescent female athletes. Given the potential to monitor the cumulative effects of long-term training at the level of renal function, this could provide appropriate feedback to adolescent female athletes regarding their physical condition. Accordingly, the purpose of this study was to clarify the accumulative effects of long-term volleyball training on renal damage, based on urinary liver-type fatty acid-binding protein (L-FABP), in adolescent female athletes. Twenty-one eumenorrhoeic female volleyball players (as baseline values; age: 16.4±0.8 years, height: 161.9±5.8 cm, body mass: 55.6±5.7 kg, BMI: 21.8±1.2 kg/m2, body fat: 24.5±3.0 % [mean±SD]) participated in this study. All athletes carried out volleyball training in the school gym, which consisted of ball handling, specialized drills, and practical game-style exercises, including physical (aerobic/anaerobic) training. The training cycle was six days per week, with approximately 2 to 2.5 hours of volleyball training per day. In order to determine the cumulative effects of tubular injury (urinary L-FABP), urine samples were collected before and after volleyball club activities on three successive days (Days 1, 3, and 5) at 0 (baseline) and 10 months (two consecutive summer seasons), respectively, for the later analysis of urinary L-FABP using chemiluminescent enzyme immunoassay. Student's T-test was performed on the analyzed data of urine samples collected prior to the club activity, using values calculated as the mean of three consecutive days. No significant difference was observed in urinary L-FABP after 10 months of volleyball training (μg/g creatinine; 1.39±1.6 for 0 month, 1.17±0.8 for 10 months, respectively). The results of this study may partially explain the possibility that training adaptation occurred or that a threshold to overtraining was not reached after one year of training. Since physiological and environmental factors such as heat stress are presumed to be intricately involved in long-term training in a non-air-conditioned indoor environment, the biomarkers used in this experiment may be important dependent variables in monitoring overtraining of female indoor athletes.

Supported partly by funds from Wesco Scientific Promotion Foundation (2022-71 to N. Y.) in Japan.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Sublingual sufentanil does not decrease tolerance to progressive central hypovolemia
Authors: Jarrard Caitlin P. , McKenna Zachary J. , Atkins Whitley C. , Foster Josh , Crandall Craig G.
Published: May 2024

Hemorrhage is a leading cause of death in both civilian and battlefield settings. Since pain often accompanies a hemorrhagic insult, the administered pain medication must not interfere with critical autonomic responses beneficial to maintaining arterial blood pressure and thus organ perfusion. Sublingual sufentanil is currently available for administration on the battlefield, but its effect on hemorrhage tolerance is unknown. This study tested the hypothesis that sufentanil impairs tolerance to progressive central hypovolemia in awake humans. METHODS: 29 participants, 15 males and 14 females (aged: 29 ± 5, weight: 74 ± 8 kg, BMI: 25 ± 2 kg/m2) participated in this double-blinded, randomized, placebo-controlled trial. Following sublingual administration of sufentanil (30 μg) or placebo, participants completed a progressive lower-body negative pressure (LBNP) protocol starting at 40 mmHg that was further reduced by 10 mmHg every three minutes until presyncope. Presyncope was defined as: continued reports of feeling faint and/or nauseous, a rapid decline in blood pressure resulting in systolic blood pressure <80 mmHg, and/or relative bradycardia accompanied by a narrowing of pulse pressure. Tolerance to LBNP, quantified as cumulative stress index (mmHg*min), was compared between sufentanil and placebo trials using a Wilcoxon Signed rank test. Arterial blood pressure, heart rate, and plasma catecholamine concentrations were compared using mixed effects models (LBNP stage x Drug). RESULTS: Tolerance to LBNP was not different between trials (sufentanil: 518 ± 203 vs. placebo: 594 ± 267, p = 0.495). Mean blood pressure decreased similarly between the two trials during LBNP (sufentanil: -23 ± 9 mmHg vs. placebo: -22 ± 10 mmHg, p< 0.001), with no main effect of drug (p = 0.498) or interaction (p = 0.935). Increases in heart rate with LBNP were similar between the two trials (sufentanil: 44 ± 25 bpm vs. placebo: 52 ± 23 bpm, time: p < 0.001) with no main effect of drug (p=0.626) or interaction (p = 0.424). Epinephrine (drug: p = 0.004, time: p < 0.001, interaction: p = 0.031) and norepinephrine (drug: p = 0.017, time: p < 0.001, interaction: p = 0.161), concentrations increased to LBNP, with post hoc analysis revealing that epinephrine concentrations were higher at LBNP 50 and presyncope (p ≤ 0.05) with sufentanil. CONCLUSION: These data demonstrate that sublingual sufentanil does not impair tolerance to simulated hemorrhage or alter the assessed mechanisms responsible for maintaining arterial blood pressure.

W81XWH-22-C-0004.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Pulmonary Fibrosis Augments CGRP-Dependent Hyperpolarization and Vasodilation of Mouse Pulmonary Arteries
Authors: Norton Charles E.
Published: May 2024

Calcitonin gene related peptide (CGRP) hyperpolarizes membrane potential (Vm) of pulmonary arterial smooth muscle cells (SMCs) and endothelial cells (ECs) through PKA-dependent activation of KATP channels. CGRP can diminish the severity of pulmonary fibrosis (PF), however, the effects on vascular signaling were poorly defined. We hypothesized that hyperpolarization to CGRP would be augmented in a mouse model of PF. PF was induced by intratracheal delivery of bleomycin (3 wk), and saline was used as a control (sham). Pulmonary arteries (PAs; 100-150 μm diameter) from male C57BL/6J mice (age, ~5 mo), were cannulated, pressurized to 16 cmH2O, and studied at 37°C. Alternatively, intact endothelial tubes were studied at 32°C following dissociation of SMCs. Vm was recorded continuously using intracellular microelectrodes. At rest, Vm was similar for SMCs (bleomycin = -43±3 mV, sham = -44±3 mV; n = 5/group) and ECs (bleomycin = -45±4 mV, sham = -44±3 mV; n=5/group). Increasing concentrations of CGRP (10−10-10−6 M) evoked hyperpolarization of Vm with greater potency in SMCs (EC50: bleomycin = 2 nM, sham = 15 nM) and ECs (EC50: bleomycin = 3 nM, sham = 8 nM) from PF mice, without changing effcacy (SMCs: bleomycin ΔVm = -24±4 mV, sham ΔVm = -21±3 mV; ECs: bleomycin ΔVm = -26±2 mV, sham ΔVm=23±4 mV). Consistently, vasodilation to CGRP in PAs preconstricted with uridine triphosphate (UTP, 5 μM; EC50) was enhanced in PF (92±6% maximum dilation;) vs. sham (83±4% maximum dilation) mice (n=5/group). Greater vasodilation and hyperpolarization of SMCs to CGRP persisted in endothelium-disrupted PAs and during treatment with L-NAME (10−4 M) indicating that ECs are not required for greater responsiveness to CGRP in SMCs. With no effect on resting Vm, inhibition of KATP channels with 1 μM glibenclamide or PKA with protein kinase inhibitor [PKI-(14-22)-amide, myristoylated; 1 μM] significantly attenuated (p<0.05) hyperpolarization of SMCs and ECs (ΔVm ≤5 mV for all groups). Both glibenclamide and PKI attenuated vasodilation to CGRP in PAs and eliminated differences between groups. In a mouse model of PF, CGRP-dependent hyperpolarization of pulmonary arterial SMCs and ECs is augmented through increased PKA-dependent activation of KATP channels leading to increased vasodilator sensitivity.

AHA CDA#931652.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Light physical activity improves lower limb perfusion asymmetries in older sedentary adults — an exploratory study
Authors: Monteiro Rodrigues Luis , Florindo Margarida
Published: May 2024

Perfusion asymmetries between lower limbs are common even in healthy young individuals, although their physiological significance is unknown. Even in the absence of vascular disease, ageing is among the determinants that seem to accentuate those differences. While it is known that physical activity affects vascular hemodynamics, its specific impact on perfusion asymmetries in healthy elderly individuals is still unclear. This study aimed to identify vascular asymmetries and their variations after a regular program of light exercise in older individuals with age-related comorbidities in the absence of peripheral vascular disease (PVD). Ten participants, mean age 62.4 ± 5.6 years old, were selected following specific criteria. Participants were mostly sedentary, combining one or more common morbidities for this age group — in particular hypertension, overweight and / or diabetes (T2D). Exclusion criteria were an abnormal Ankle-Brachial Index assessed in a standing position at rest and evidence of compromised mobility. All procedures respected the principles of good clinical practice, being previously submitted and approved by the institutional Ethical Commission. Lower limb perfusion was assessed in both feet (anteromedial region) at two time points — day zero (D0) and thirty days later (D30) — using two optical-based technologies — Laser Doppler Flowmetry (LDF) and Polarized Spectroscopy (PSp). These two technologies measure at different depths, with LDF providing deeper tissue readings. During this evaluation period, participants underwent a daily structured program of light exercises based on the FITT principles (F, frequency; I, intensity; T, time and T, type of activity/activity performance) centred in the lower limb perfusion. The group revealed significant asymmetries at D0, where the right foot consistently showed higher values with both technologies correlating positively. At D30, LDF values increased by 57.5% in both feet, meaning that asymmetries disappeared. No significant changes were observed with PSp. Basic cardiovascular functions such as blood pressure and mean arterial pressure were also evaluated, showing significant decreases in systolic pressure and mean arterial pressure. These encouraging results suggest that regular physical activity, even if light in intensity and duration, improves overall hemodynamics and specifically raises perfusion in the lower limbs. These findings should be further explored with the aimof prevention and treatment of PVD.

This research was financed by national funds through FCT - Foundation for Science and Technology, I.P. (Portugal), under the [UIDB/04567/2020] and [UIDP/ 04567/2020] programs.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
TRIM Enhances Dystrophic Muscle Function 70 Days Post Treatment
Authors: Kendra Jacob , Naman Alexandra , Brow Richard , Segal Steven , Morton Aaron
Published: May 2024

Background: Duchenne Muscular Dystrophy (DMD) is associated with limb muscle dysfunction caused by progressive weakness and degeneration of skeletal muscle. Current FDA-approved therapeutic strategies are less effective than originally hoped. Our alternative approach was to develop a novel biomaterial, Time Release Ion Matrix (TRIM), shown to release angiogenic ions and enhance muscle structure and function at 14 days post injection (dpi) in dystrophic (D2. mdx) mice. However, the long-term effects of TRIM are unknown. Hypothesis: At 70 days post injection in D2. mdx mice TRIM will: 1) enhance isometric force and myofiber cross-sectional area (CSA) of the tibialis anterior (TA) muscle; and 2) promote vascular endothelial growth factor (VEGF) availability and muscle vascularity. Methods: The right and left TA of adult male D2. mdx mice (n=6-7, age 5 months) were injected with saline alone (control) or 250 μg of TRIM suspended in saline. At 70 dpi, the left TA was isolated for in situ muscle force measurements and histological analysis; the right TA was frozen for biochemical analysis. Muscle cross-sections were immunostained for laminin (myofiber borders), DAPI (nuclei), and CD31 (endothelial cells). An ELISA for VEGF was performed on homogenates of frozen muscles. Results: TA’s injected with TRIM increased peak isometric force (means ± SE: TRIM 70.9 ± 1.8 g; Saline, 65.9 ± 1.1 g; P= 0.04). TRIM-treated TA’s had a 2.2-fold increase in relative frequency of myofibers >1000 μm2 (TRIM, 31.8 ± 3.7%; Saline, 14.4 ± 1.9%; P= 0.001), and reduced the frequency of myofibers <400 μm2 by 32% (TRIM, 38.6% ± 2.8; Saline, 56.5% ± 3.5; P= 0.001). DAPI staining revealed a 50% increase in central myonuclei indicative of regenerated myofibers (TRIM, 30.2 ± 1.7%; Saline, 20.2 ± 1.3%; P=0.0006). Microvessel area (CD31 staining; μm2) was 2.1-fold greater in treated TA’s (TRIM, 135.6 ± 8.7 μm2; Saline, 63.6 ± 4.5 μm2; P=0.0001). In muscle homogenates, TRIM increased [VEGF] (TRIM, 139 ± 10%; Saline, 100 ± 6%; P= 0.009) Conclusion: Results support the hypothesis that 70 days following injection of TRIM into the TA of dystrophic mice, muscle force and myofiber CSA are enhanced. Moreover, TRIM enhances VEGF with increased vascularity, suggesting that the angiogenic effects of TRIM complement those on myogenesis and contractile function towards restoring muscle structure and function in DMD.

University of Missouri Coulter Biomedical Accelerator (SSS), Texas A&M Department of Kinesiology and Sport Management (ABM).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Skeletal Muscle Derived Cells from Old Human Donors Show Increased Mitochondrial Lipid Peroxidation and Reduced Mitochondrial Function
Authors: Arevalo Jose , Avalos Heidi , Brooks George , Vazquez-Medina Jose Pablo
Published: May 2024

Skeletal muscle undergoes atrophy with age progression resulting in decreased mitochondrial function. Similarly, age-related increases in mitochondrial oxidant generation can promote mitochondrial oxidative damage, but the relationship between increased oxidant stress and mitochondrial function is not well understood. Here, we profiled changes in mitochondrial function and mitochondrial lipid peroxidation in intact primary skeletal muscle progenitor cells (myoblasts) derived from the Rectus abdominis muscle of healthy young (19.67 ± 1.70 years) and old (67.0 ± 1.41 years) humans. Using metabolic flux assays, we found that cells derived from young humans showed higher basal and maximal oxygen consumption rates compared to cells derived from old humans (basal: 22.67 ± 6.53 vs. 10.81 ± 5.69; maximal: 41.02 ± 15.20 vs. 17.33 ± 4.84 pmol/min/protein, p < 0.001). Similarly, cells derived from young humans also showed higher ATP production and spare respiratory capacity (ATP: 18.79 ± 5.17 vs. 9.15 ± 4.91; SRC: 18.35 ± 9.62 vs. 6.52 ± 3.42 pmol/min/protein, p < 0.001). In contrast, using live-cell fluorescence microscopy, MitoTracker red and the mitochondrial-target lipid peroxide probe MitoPeDPP, we found higher mitochondrial lipid peroxidation levels in cells derived from old than young humans ( p = 0.0007). We then evaluated whether peroxiredoxin 6 (Prdx6), an enzyme that repairs lipid peroxidation through its phospholipid glutathione peroxidase and phospholipase A2 activities, impacts mitochondrial function using CRISPR/Cas9-mediated knockouts of Prdx6 in C2C12 myoblasts and extracellular flux assays. Spare respiratory capacity was lower in cells with full Prdx6-KO than in cells transfected with non-target gRNAs (NT: 295.10 ± 18.59 vs. Prdx6-KO: 242.20 ± 17.93; p = 0.05). These results show that mitochondrial function decreases with age along with increases in mitochondrial lipid peroxidation in primary muscle cells derived from old humans. Similarly, these results show that the Prdx6 supports mitochondrial function. Overall, our data contributes to our understanding of the mechanistic drivers of age-related skeletal muscle mitochondrial dysfunction.

NIGMS-R35GM146951 NIA-R01AG059715.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Impact of exercise on uncoupling protein 1 and macrophage phenotype in mesenteric adipose tissue in an animal model of endometriosis
Authors: Cruz Myrella L. , Torres-Pirela James , Chompre Gladys , Vazquez-Ubides Ernesto , Rivera-Arce Luis A. , Appleyard Caroline B.
Published: May 2024

Endometriosis is a gynecological disorder characterized by growth of endometrial tissue outside the uterine cavity, with symptoms which may include chronic pelvic pain and infertility resulting in a decreased quality of life. Previous studies in our laboratory demonstrated that endometriosis animals have increased mesenteric adipose tissue (MAT), inflammation, and growth of implanted endometrial vesicles which are decreased by voluntary exercise. The levels of Uncoupling Protein 1 (UCP-1), a mitochondrial protein, are known to be increased by exercise in rodents, promoting thermogenesis and decreasing inflammation. Exercise can also increase expression of peroxisome proliferator-activated receptor γ (PPARγ), a member of the nuclear receptor superfamily. When activated PPARγ polarizes the macrophages into an anti-inflammatory M2 state, which can stimulate white adipose tissue beiging. We hypothesized that voluntary wheel running exercise can increase UCP-1 and M2 macrophages, decreasing MAT and endometrial vesicle size. Aim: To assess the impact of voluntary exercise on UCP-1 expression and macrophage phenotype in MAT of an animal model of endometriosis. Methods: Endometriosis was induced by implanting uterine tissue on the intestinal mesentery of female Sprague Dawley rats while control group only received sutures (SHAM). Exercise rats had access to a running wheel after surgery (ENDO-EX or SHAM-EX), while non-exercised animals didn’t (ENDO and SHAM; n=10-11/group). After sixty days, animals were sacrificed, and MAT was collected to determine CD68, UCP-1 and PPARγ expression by immunofluorescence staining. Results: Vesicles from ENDO-EX animals exhibited significantly decreased average weight (p<0.01) and smaller average total area (p<0.01) compared with the ENDO group. Endometriosis animals showed increased mesenteric adipose tissue when compared to sham group (p<0.01), which was reduced by voluntary exercise (p<0.001). Macrophage infiltration, UCP-1 and PPARγ expression increased with exercise. Conclusions: Increased UCP-1 and anti-inflammatory M2 macrophages following exercise may result in browning of MAT which can have a role in reducing the development of vesicles in the endometriosis model. These findings suggest that exercise may be a potential complementary therapeutic strategy for managing endometriosis symptoms.

This work was supported by R15AT009915, R16GM149365, T32GM144896, PRI MD Summer Program and Porter Physiology Development Fellowship.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
The Impact of Goode Health LLC Superfood Chocolate Blend Beverage on Peripheral Macro and Microvascular Function
Authors: Ortiz Alison , Kolade John O. , Perry Ken A. , Shah Prarthi J. , Brothers R. Matthew
Published: May 2024

Cardiovascular disease (CVD) is the leading cause of death in the US and world-wide. The are many risk factors associated with elevated risk for and prevalence of CVD; however, it is well documented that reduced macro and microvascular function/health is a major contributing factor. The mechanisms are multifactorial however, reduced vasodilatory reactivity, secondary to elevated oxidative stress and/or inflammation contribute to elevated disease risk. Diets and/or interventions high in antioxidants, polyphenols, and/or anti-inflammatory properties reduce CVD and metabolic disease risk. Furthermore, this is mediated in part through improvements in vascular function. This study tested the hypothesis that 2-weeks of increased daily consumption of a beverage high in antioxidants, polyphenols, and anti-inflammatory properties would improve well-validated indices of peripheral macro and microvascular function in a cohort of Hispanic individuals. METHODS: Six Hispanic individuals (4 males; age: 42±14 yr.; BMI 32±7 kg/m2) participated. All measures were assessed before (pre) and following (post) 14-days of increased daily consumption of the Goode Health LLC Superfood Moroccan Chocolate Blend. During the intervention participants added the chocolate blend powder mix (~28 g) to 8 oz water twice daily. This beverage is high in healthy ingredients including plant-based proteins, prebiotic fiber, antioxidant polyphenols, and anti-inflammatory properties. Peripheral macro and microvascular function/health were assessed pre- and post-intervention as vasodilation in the brachial artery (flow mediated vasodilation; %FMD) and reactive hyperemia (peak mean forearm blood velocity (FBVmean)) in the forearm vasculature respectively following 5-min of forearm ischemia induced by suprasystolic cuff occlusion. RESULTS: Peripheral macrovascular function assessed as %FMD tended to be augmented following Goode Health LLC beverage consumption (Pre: 4.2±2.2 % vs. Post: 5.8±1.6 %, P=0.08). Whereas peripheral microvascular function assessed as peak FBVmean was augmented following the intervention (Pre: 70±17 cm·s−1 vs. Post: 78±20 cm·s−1, P=0.04) CONCLUSION: These preliminary data indicate a positive effect of Goode Health LLC Superfood Moroccan Chocolate Blend consumption on indices of peripheral macro and microvascular function/health. Future studies will continue to expand upon these findings in a larger cohort.

Goode Health LLC.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Myoglobin: A versatile age-old oxygen carrying hemoprotein and its emerging role in metabolite regulation in diverse tissues
Authors: Adepu Kiran Kumar , Anishkan Andriy , Adams Sean , Chintapalli Sree
Published: May 2024

Myoglobin (Mb) is an age-old heme containing cytoplasmic protein primarily expressed in heart and skeletal muscles, which is capable of rapid release of O2 during the periods of hypoxia or anoxia. The canonical view of the primary physiological function of Mb is that it is a tissue oxygen (O2) storage protein supporting mitochondrial oxidative phosphorylation especially as the tissue O2 partial pressure ( pO2) drops and Mb increasingly offloads O2. For the past 50 years, many investigators are constantly exploring wide-range of physiological functions and metabolic regulation activities of Mb. Advanced genetic engineering tools and molecular techniques revealed important new insights and provided additional functions of Mb. However, accumulating evidence indicates that this paradigm is too narrow, especially in light of recent findings supporting plausible functions for Mb in lipid traffcking and sequestration, binding of small molecules such as lactate (LAC), pyruvate (PYR), glucose (GLU), polyamines, and glutathione (GSH), and “ectopic” expression in some types of cancer cells. Data from Mb knockout mice (Mb−/−) and biochemical models suggest additional metabolic roles for Mb, especially regulation of nitric oxide (NO) pools and modulation of thermogenic brown adipose tissue (BAT) bioenergetics and lipid storage phenotypes. From these and other findings in the literature over many decades, it may be contemplated that the primary role for Mb under most conditions for Mb besides delivering O2 in support of oxidative phosphorylation, but also serve as an O2-sensor that modulates intracellular O2- and NO-responsive molecular signaling pathways. This paradigm shift reflect a fundamental change in how oxidative metabolism and cell regulation are viewed in Mb-expressing cells such as skeletal muscle, heart, brown adipocytes, and select cancer cells. Herein, we present historic and emerging views related to the physiological roles for Mb, and working models illustrating the possible importance of interactions between Mb, gases, and small molecule metabolites in regulation of cell signaling and bioenergetics.

USDA-ARS project 6026-51000-010-06S, Sturgis Foundation Grant AWD00054750 and ACRI-ABI Investigator Initiated Grant Award GR037175-4450S ABI.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Hibernating at High Temperatures Increases Variability in Arousal Dynamics
Authors: Yankaway Raizel , van Breukelen Frank , Hindle Allyson G , Utz Jenifer
Published: May 2024

In the winter, and presumably due to low resource availability, many mammals enter into a state of torpor wherein body temperature approaches that of ambient temperature and oxygen consumption rates can be as low as 1/100th of active rates. The canonical hibernation season is not static. Rather periods of torpor are interrupted by predictable periods of euthermy called interbout arousals which allows for a resetting of homeostatic processes. Here, we exposed golden-mantled ground squirrels to a range of ambient temperatures including high temperatures (4, 12, 20, 25, and 30°C). Preliminary analyses demonstrated higher temperatures resulted in decreased maximum rates of rewarming. On average, at 4°C ambient temperature rewarming was 0.14 °C per minute, while at 30°C ambient temperature the average maximum rate of rewarming was 0.012°C per minute. In addition, higher temperatures had a 2-fold higher relative time index which is defined as the time required to reach maximum rate of rewarming divided by the total arousal duration. Lastly, the interbout arousals increased 5-fold at warmer temperatures, lasting 12 hours at 4°C and 66 hours at 30°C. We interpret these data to suggest high temperature torpor leads to homeostatic issues wherein key processes are poorly coordinated. The result is an inherent increase in variability between individual squirrels and a loss of predictability of key hibernation aspects.

NASA TRISH Department of Education NSF.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Effects of antagonism of thromboxane-prostanoid receptor on alcohol-associated liver disease
Authors: Ai Weilun , Casey Carol , Saraswathi Viswanathan
Published: May 2024

Backgrounds: Alcohol-associated liver disease (ALD) is one of the leading causes of liver diseases. Thromboxane-prostanoid receptor (TP-R) is widely expressed in the liver and is activated by thromboxane A2 (TXA2). A previous study reported an increase in TP-R mRNA level in liver after ethanol feeding. Preclinical studies have documented that TP-R antagonists exert a protective effect against cardiovascular and liver diseases. In particular, TP-R antagonist is reported to attenuate ALD in rodents. However, the mechanism(s) by which antagonizing TP-R attenuates ALD remains unclear. Methods: Herein, we used the chronic plus binge ethanol feeding model. Briefly, male, C57BL/6 wild-type mice (8-week) were fed a Lieber-Decarli ethanol (5% v/v) diet (ET, n = 10) or isocaloric control diet (CON, n = 6) for ten days followed by a single binge administration of ethanol or maltose-dextrin via oral gavage. A cohort of ethanol-fed mice received SQ 29,548, a TP-R antagonist (ET+SQ, n = 8) by oral administration. Results: Western blot analysis showed that the protein level of thromboxane A2 synthase 1 ( P<0.05), responsible for TXA2 production, was upregulated in the mouse liver upon ethanol exposure. Of note, ethanol feeding significantly increased plasma aspartate transferase (AST) level ( P<0.05), which was abolished by SQ administration ( P<0.05). Moreover, compared with CON mice, ET mice showed an increase in liver protein levels of pro-inflammatory markers, including TNFa ( P<0.05), cluster of differentiation 68 (CD68, P<0.001), and vascular cell adhesion protein 1 ( P<0.05). In addition, the pro-fibrogenic markers including collagen type 1 alpha 1 chain (COL1A1, P<0.05) and matrix metalloproteinase 9 (MMP9, P<0.01) were also increased in ET mice. However, these alterations were not found in ET+SQ mice compared to their controls. In particular, ET+SQ mice exhibited a marked reduction in hepatic protein levels of CD68 ( P<0.001), COL1A1 ( P<0.001), and MMP9 ( P<0.01) versus ET mice. Interestingly, we noted that ethanol consumption decreases the protein level of NADH:ubiquinone oxidoreductase subunit B8 (NDUFB8), a component of mitochondrial complex I, in mouse liver ( P<0.05), which was reversed by SQ administration( P<0.05). Conclusion: These findings suggest that blockade of TP-R activity attenuates ethanol-induced liver inflammation and fibrosis possibly through improving the function of mitochondrial complex I.

This study was supported by the NIH-NIAAA P50 award-Alcohol Center of Research-Nebraska (P50AA030407-5130).

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
One minute of stair climbing and descending reduces postprandial insulin and glucose with three-minutes improving insulin resistance following a mixed meal in young adults: A Randomized Controlled Trial
Authors: Moore Jeff , Kressler Jochen
Published: May 2024

Glycemic markers, including postprandial glucose, insulin, and insulin sensitivity, are strong predictors of morbidity and mortality in individuals with and without diabetes. Stair-climbing and -descending (SCD) at a comfortable pace for as little as 1 to 3 minutes after a sugary beverage (300 kilocalories; 100% carbohydrate) improves glucose and insulin, with insulin sensitivity improving with as little as 10 minutes. Objective: To determine if benefits to glucose, insulin, and insulin sensitivity are seen with SCD following consumption of a meal with mixed macronutrients. Hypothesis: SCD will improve to glucose, insulin, and insulin sensitivity in a dose response manner following a mixed meal. Methods: In a randomized, controlled, crossover trial, young adults (N=31) in apparent good health performed SCD for 0, 1, 3, and 10 minutes after a mixed meal (650 kilocalories; 53% carbohydrates, 33% fat, and 14% protein). Differences in glucose, insulin, and insulin sensitivity (ISI) from baseline to 30 minutes were analyzed using a mixed-effects ANOVA. Results: A significant fixed-effect was found for change in glucose [F(2.551,67.17)=4.724, p=.0071)], insulin [F(2.692,74.49)=11.28, p<.0001)], and ISI [F(2.127,56.00)=5.848, p=.0042)]. Compared to control, changes in glucose (mean (95%CI)) were significantly lower after 1 min (-14 (-7 to -21) mg/dL, p=.0006), 3 min (-18 (-9 to -28) mg/dL, p=.0007), and 10 min (-10.0 (-1 to -20) mg/dL, p=.0387); changes in insulin were significantly lower after 1 min (-1.8 (-0.8 to -2.8) μIU/mL, p=.0011), 3 min (-2.8 (-1.7 to -4.0) μIU/mL, p<.0001), and 10 min (-1.1 (-0.1 to -2.0) μIU/mL, p=.0329); and changes in ISI were significantly higher after 3 min (2.4 (1.2 to 3.6), p=.0003) and 10 min (1.3 (0.3 to 2.4), p=.0143) but not 1 min (1.2 (0.0 to 2.5), p=.0587). Conclusion: Postprandial glucose and insulin were improved with as little as 1 minute, and insulin resistance improved with as little as 3 minutes, of SCD at a self-selected, comfortable pace, after consumption of a mixed meal in apparently healthy young adults.

None.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.