bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic modification of cardiac fibroblasts in adult rats using adeno-associated virus serotype 9
Authors: Nieto Bridget , Cypress Michael , Chandran Sanjana , Dugan Matthew , O-Uchi Jin , Jhun Bong Sook 
Published: May 2024

Cardiac fibrosis is a process involving pathological extracellular matrix remodeling as well as cardiac fibroblast (CF) activation in response to cardiac injury and stress, which is frequently associated with cardiac dysfunction. Therefore, understanding the molecular mechanisms underlying CF activation is critical to develop successful therapies for treating cardiac fibrosis. CF-specific gene modifications in mouse models have been reported as key tools for cardiac fibrosis research. Although rat cardiac disease models also offer many of the same advantages as the mouse models, there are no rat models that employ CF-specific conditional gene modification. Here, we attempted CF-specific gene introduction in rats using adeno-associated virus serotype 9 (AAV9), allowing us to develop fast and simple rat cardiac disease models rather than establishing transgenic rat lines. AAV9 carrying a CF-specific human TCF21 (hTCF21) promoter and a transgene of interest was generated and introduced into adult rats via tail vein injections. Since we previously reported in cultured CFs that protein kinase D (PKD) activation at the outer mitochondrial membrane (OMM) induces mitochondrial fragmentation via phosphorylation of a mitochondrial fission protein DRP1, we generated an OMM-targeted dominant-negative mutant of PKD (termed mt-PKD-DN) to specifically inhibit PKD activity at the OMM in CFs in vivo. In vivo cardiac function, gene expression, protein expression, and mitochondrial morphology were assessed 2-10 weeks after AAV9 injection by echocardiography, quantitative RT-PCR, immunohistochemistry, and transmission electron microscopy (TEM), respectively. AAV9-hTCF21-injected rats maintained normal cardiac dimensions and contractile function compared to aged-matched control rats. Using AAV9-hTCF21-EGFP, we confirmed organ-specific (i.e., heart) and cell type-specific (i.e., CF-specific) expression of GFP. Next, we injected AAV9-hTCF21-mt-PKD-DN or -luciferase (Luc) as a control in adult rats. TEM images from fixed rat ventricular tissues revealed a significant increase in mitochondrial aspect ratio and mitochondrial perimeter in CFs with AAV9-hTCF21-mt-PKD-DN compared to AAV9-hTCF21-Luc, indicating that PKD inhibition at the OMM induces mitochondrial elongation in CFs in vivo. In contrast, no significant change in mitochondrial morphology was observed in the cardiomyocyte area. In summary, we successfully achieved a CF-specific gene delivery to the adult rat hearts in vivo, demonstrating the potential of a simplified CF-specific rat transgenic model using the AAV9-hTCF21 system. NIH/NHLBI R01HL160699. 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.
Fiber type specific myonuclear and satellite cell content comparisons between the vastus lateralis and soleus muscles in humans
Authors: Boyd Gerard , Skiles Chad , Robbins Ethan , Gouw Aaron , Minchev Kiril , Ryder Jeffrey , Ploutz-Snyder Lori 
Published: May 2024

Objectives: The purpose of this study was to compare fiber type specific myonuclear and satellite cell number of the vastus lateralis and soleus muscles in humans. Hypotheses: Myonuclear number (MNN), myonuclear domain (MND), and satellite cell number (SCN) would be similar within each fiber type between the vastus lateralis and soleus. Methods: Muscle biopsies from the vastus lateralis and soleus of 24 individuals (34±7y, 24-55y) were sectioned, immunofluorescently stained, and analyzed for MNN, MND, and SCN in slow (myosin heavy chain (MHC) I) and fast (MHC IIa) muscle fibers. SCN was determined only in MHC I fibers for the soleus. MNN and MND were compared for 24 individuals, while SCN was compared for 19 individuals. Results: MNN was similar in MHC I (3.32±0.81 vs. 3.66±0.65 myonuclei/fiber, P=0.067) and IIa (3.63±0.82 vs. 3.83±0.68 myonuclei/fiber, P>0.05) fibers of the vastus lateralis and soleus. Similarly, MND was not different in MHC I (1649±305 vs. 1673±340 μm2/myonuclei, P>0.05) and IIa (1705±313 vs. 1819±394 μm2/myonuclei, P>0.05) fibers of the vastus lateralis and soleus. However, SCN was 62% higher (p<0.05) in MHC I fibers of the soleus (0.127±0.039 satellite cells/fiber) compared with MHC I fibers of the vastus lateralis (0.083±0.024 satellite cells/fiber). Conclusions: The literature is void of comparisons of myonuclei and satellite numbers across different human muscles. These initial results suggest myonuclear number and the area “governed” by each myonuclei (i.e., the myonuclear domain) appears to be similar within the two main fiber types found in the vastus lateralis and soleus muscles. Interestingly, within the same slow fiber type (i.e., MHC I fibers) across these two muscles, it appears the soleus is programmed to have a substantially higher satellite cell content. The basis for this intrinsic difference in slow myofiber satellite profile may be related to the differences in daily myocellular activity between the vastus lateralis and soleus. This research was supported by the National Aeronautics and Space Administration, NNJ06HF59G; the Institute for Translational Sciences at the University of Texas Medical Branch, supported in part by a Clinical and Translational Science Award (UR1TR000071) from the National Center for Advancing Translational Sciences, National Institutes of Health; the NASA Flight Analogs Project; and the Human Bioenergetic Program at Ball State 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.
Mitochondrial involvement in the metabolic defects evoked by hepatocyte-specific BBSome deficiency
Authors: Guo Deng F , Zhao Yuying , Rouabhi Younes , Rahmouni Kamal 
Published: May 2024

The BBSome, a protein complex of 8 Bardet-Biedl syndrome (BBS) proteins including BBS1, has emerged as an important regulator of metabolic function. BBSome deficient human and mice display several metabolic features including obesity and type 2 diabetes. Here, we show that mice lacking the BBSome specifically in liver which were generated by crossing the Bbs1fl/fl mice with liver-specific (albumin) AlbCre mice exhibit significantly higher lipid droplets in liver, by Oil Red-O staining, and in primary cultured hepatocytes (5.7%±0.4% vs 2.4%±0.6%, control), and by Transmission electron microscope (TEM). AlbCre/Bbs1flox also have elevated fasting glucose (169± 14 vs 136±8 mg/dL, p<0.05) and impaired insulin sensitivity. In addition, insulin-induced activation of AKT was significantly decreased in the liver (2.6±0.07 vs 6.6± 0.34 AU, p<0.05), but not in white adipose tissue and skeletal muscle, of AlbCre/Bbs1flox mice. Using immunohistochemistry, we found that insulin receptor level in plasma membrane was decreased by 24.2±6.8% in primary cultured hepatocytes derived from AlbCre/Bbs1flox mice which explains the insulin resistance. Our previous work implicating the BBSome in the regulation of mitochondria led us to hypothesize that mitochondria dysfunction contributes to the development of metabolic defects in AlbCre/Bbs1flox mice. TEM studies revealed that mitochondria were significantly larger and longer in hepatocytes of AlbCre/Bbs1flox mice than controls. This was associated with decreased levels of Dynamin-related protein 1 (DRP1), which critically regulates mitochondrial function through fission. Next, we asked whether the mitochondrial defects may explain the insulin receptor mistraffcking in BBSome deficient hepatocytes. To test this, hepatocytes were infected with feline immunodeficiency virus that express an active mutant form of DRP1 (FIV-DRP1S637A). Interestingly, insulin receptor localization in the plasma membrane was significantly higher in hepatocytes of Bbs1fl/fl/AlbCre­ mice infected with FIV-DRP1S637A pointing to mitochondrial defects as the underlying cause of insulin receptor mislocalization induced by hepatic BBSome deficiency. Taken together, these findings demonstrate that BBSome regulation of metabolic function involve mitochondria. NIH and VA. 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.
LLM-Generated Multiple Choice Practice Quizzes for Pre-Clinical Medical Students; Use and Validity
Authors: Berman Jonathan , McCoy Lise , Camarata Troy 
Published: May 2024

Multiple choice questions (MCQs) are frequently used in medical education, and practice questions are commonly requested by students. Automated generation of MCQs in board-exam format would potentially save significant time for faculty and generate a wider set of practice materials. The goals of this study were to explore the feasibility of using ChatGPT by OpenAI to generate USMLE/COMLEX style practice quiz items as study aids, and to analyze how and to what extent medical students would voluntarily use these quiz items to prepare for exams. Researchers gave second year medical students studying renal physiology access to a set of practice quizzes with chatGPT generated questions. The number and timing of click throughs to the quizzes, number of question attempts, and scores of completed quizzes were anonymously recorded by custom quiz software. Practice questions were accessed 15,245 times by a class of 399 students. The majority of quiz click throughs occurred in the time immediately preceding exams. To analyze the quality of exam items, they were evaluated by independent experts for quality and adherence to USMLE/COMLEX guidelines. These results demonstrate the feasibility of LLM-generated practice questions in medical education when supervised by a human faculty. Supported By a Grant from the New York Institute of Technology Emerging Technology Group. 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 ‘12 Problem’ Revisited
Authors: Anderson Curt , Stephens Trent 
Published: May 2024

Ask nearly any high school, college or graduate level health professional student how many cranial nerves there are, and the classic response is well known and not correct. Most of us know the long-held problem, the inaccurate textbooks, and are tired of saying ‘well, yes, but not really; memorize them anyway’. Its disingenuous, and we’re weary of the differences between textbook and reality. Here we provide a brief overview of how we historically arrived, a description of what it should be and a solution. This proposal results in 14 cranial nerves, doesn’t upset the numbering system and is easily adoptable and in agreement with Terminología Anatómica. 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.
Riding for Focus as a Pathway to Improved Mental Health in Middle School Students
Authors: Murillo Starla , Dementyev Fletcher , Bello-Soto Benjamin , Wilson Hunter , Philipsheck Ashtyn , Bhatt Eshan , Madison Kai 
Published: May 2024

Youth mental health remains in a critical state even in a post-COVID pandemic world. Exercise is a well-regarded method to boost mental health and well-being in all age groups. The Riding 4 Focus (R4F) program is a cycling education program designed to equip students with basic cycling handling skills and introduce students to the lifetime physical activity of cycling. A secondary outcome of this program is to improve the behavioral health and well-being of adolescents in middle schools, primarily aged 10-14. The current study examined associations between participating in the R4F program and mental health and well-being in those with specific unmodifiable risk factors including gender, socioeconomic, and racial identity. Anonymous online surveys were collected from 3924 adolescent participants before the R4F program and 3289 students after the cycling program across 31 schools during the fall 2021 and spring 2022 semesters. Psychosocial well-being was quantified using the WHO-5 and PSC-17-Y metrics. Using non-parametric test statistics, the data shows a significant increase in the mental health and well-being of participants after the program. Further analysis revealed that participation in the R4F program was associated with improved psychological health and well-being of minority and low-income adolescents, as well as protective associations for both genders. Although these findings are encouraging, the effcacy of the program depends on a number of factors, and future studies are needed to assess causality. Outride, Loma Linda University School of Medicine, University of Redlands Summer Research Program, P20MD006988. 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 Acute Isometric Handgrip Exercise on Vascular Function in Children and Emerging Adults with Congenital Heart Disease
Authors: Khan M. Rafique , Boyes Natasha G. , Luchkanych Adam M.S. , Al-Mouaiad Al-Azem Ibrahim , Jurrissen Thomas J. , Erlandson Marta , Wright Kristi D. 
Published: May 2024

Endothelial dysfunction is common in congenital heart disease (CHD). Isometric handgrip (IHG) exercise may improve endothelial function; however, whether this applies to patients with CHD is unknown. We investigated brachial artery flow-mediated dilation (FMD) pre- and post- acute IHG exercise using duplex ultrasound in CHD and healthy controls (CTL; n=19 (7 F) vs. 21 (9 F), age: 13±4 vs. 13±4 y). Whereas IHG improved mean FMD in controls, it had no effect on the mean FMD response in patients with CHD. Subsequently, participants within each group were categorized based on ΔFMD response (post-pre IHG FMD), in which those that experienced a decrease were classified as non-responders (NRESP) and those that experienced an increase were classified as responders (RESP). Among NRESP, ΔFMD was lower in CHD vs. controls ( p=0.0224). Among RESP, ΔFMD was lower in CHD vs. controls ( p=0.0543). Data during pre-occlusion in NRESP from pre- to post-IHG exercise showed improved antegrade shear rate (condition effect, p=0.0078), retrograde shear rate (interaction effect, p=0.0410), and oscillatory shear index (interaction effect, p=0.049) in CHD compared to controls. Potentially, IHG exercise enhanced vascular sensitivity to shear, resulting in an increase in baseline diameter and reduced FMD in CHD NRESP. Thus, reduced FMD after acute IHG exercise is influenced by improvements in resting shear rate parameters in patients with CHD. Saskatchewan Health Research Foundation, Heart and Stroke Foundation of Canada. 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.
Incomplete reverse remodeling in aged mice exposed to pulmonary hypertension-induced right ventricular failure
Authors: McNair Benjamin , Azmerin Maria , Thornburg Joshua , Bhavsar Vaishnavi , Matthews Julian , Bruns Danielle 
Published: May 2024

Right ventricle (RV) function is the strongest predictor of survival in pulmonary hypertension (PH) and age-related HF; however no therapies exist to improve RV function. Understanding mechanisms by which the RV undoes pathological remodeling (reverse remodeling) might aid in identifying therapies for this unmet need. Our objective was to determine whether the aged RV can undergo reverse remodeling following pathological afterload (PH). We hypothesized that return to normoxia after hypoxia-induced PH would result in attenuation of RV mass and improved RV function. We exposed male and female aged (~18 months) C57Bl6 mice to hypobaric hypoxia (HH) for 4 weeks before returning them to normoxia for 3 (WK3RR) or 6 (WK6RR) weeks. HH induced RV hypertrophy by RV myocyte area which was attenuated at Wk3RR and WK6RR in both male (Con: 425 μm2 ± 104, HH: 740 μm2 ± 125, WK3RR: 447 μm2 ± 129, WK6RR: 530 μm2 ± 187) and female mice (Con: 340 μm2 ± 116, HH: 770 μm2 ± 35, WK3RR: 516 μm2 ± 186, WK6RR: 655 μm2 ± 224). HH stimulated fibrosis by collagen deposition that was also reversed during normoxia re-exposure in male mice only (Con: 4.1% ± 1.0, HH: 10.8% ± 0.8, WK3RR: 4.2% ± 0.8, WK6RR: 2.5% ± 0.7). However, HH decreased RV systolic function by fractional area change (FAC) that was also not rescued by normoxia re-exposure. The aged RV can undergo morphological reverse remodeling in response to HH; however RV function does not improve with resolution of afterload. Further investigation into the mechanisms of reverse remodeling may identify potential drug therapies for maladaptive RV remodeling. AHA-Predoctoral Fellowship 897622 (BDM). 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.
Co-transplantation of hiPSC-Derived Mesenchymal Stem Cells and Cardiomyocytes Enhances Cardiac Regeneration After Myocardial Infarction
Authors: Sridharan Divya , Alvi Syed Baseeruddin , Mergaye Muhamad , Ahmed Uzair , Forehand Abbey , Nottke Katie , Khan Mahmood 
Published: May 2024

Nearly a billion cardiomyocytes (CMs) are lost during an acute myocardial infarction (AMI) which eventually leads to heart failure. While most conventional treatments for AMI are only palliative, transplantation of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hiPSC-CMs) has been shown to improve cardiac function. However, the use of hiPSC-CMs has been limited by their poor engraftment and survival in the ischemic microenvironment post-MI. Since hiPSC-derived mesenchymal stem cells (hiPSC-MSCs) have been shown to promote cardioprotection via paracrine mechanisms, we hypothesized that co-transplantation of hiPSC-CMs and hiPSC-MSCs in ischemic hearts may improve cardioprotection and engraftment of transplanted hiPSC-CMs. We co-cultured hiPSC-CMs and hiPSC-MSCs and assessed the changes in morphology (TEM, ICC), gene expression (qRT-PCR), and cardiac function (MEA, and calcium transients) under normoxia and hypoxia (1% O2). We observed increased maturation (elevated β-MHC expression, higher amplitude of contraction, increased sarcomere alignment) in hiPSC-CMs cultured in hiPSC-MSC derived conditioned medium. On the other hand, we observed enhanced survival (TUNEL assay) of hiPSC-CMs co-cultured with hiPSC-CMs following hypoxic insult. Additionally, following intramyocardial transplantation of (a) hiPSC-CMs, (b) hiPSC-MSCs or (c) hiPSC-CMs + hiPSC-MSCs (3:1) in a mouse MI model, we observed improved cardiac function, LVEF (p < 0.01) and FS (p<0.01) in all three groups as compared to MI-only group. We also observed effcient hiPSC-CM engraftment (human-specific markers, cTnT and HNA) in both hiPSC-CM-only and hiPSC-CM + hiPSC-MSC groups at 4-weeks post-MI. Furthermore, we observed increased angiogenesis (α-SMA, CD31) in the hiPSC-MSC-only and hiPSC-CM + hiPSC-MSC groups, as compared to control and hiPSC-CM-only groups. Taken together, our results showed that co-transplantation of hiPSC-MSCs and hiPSC-CMs can be explored as a novel combinatorial therapy for myocardial regeneration post-MI. Funding: AHA postdoctoral fellowship to DS (916599), and NIH RO1 HLHL136232 and OSU Start-up funds to MK. 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.
Critical Environmental Limits for Middle-Aged Adults (PSU HEAT Project)
Authors: Fisher Kat , Cottle Rachel , Wolf S. Tony , Kenney W. Larry 
Published: May 2024

Critical environmental limits are the combinations of temperature and humidity above which heat balance cannot be maintained for a given metabolic heat production. Our lab has previously established critical environmental limits for young and older adults; however, these limits have yet to be established for middle-aged adults. The purpose of the present study was to (1) identify critical environmental limits for middle-aged adults, and (2) investigate age-related differences in critical environmental limits at a low metabolic rate reflecting activities of daily living across the adult age spectrum. Twenty-six older (71±5 yrs, 14F/12M), 36 middle aged (51±9 yrs, 26F/10M), and 27 young adults (23±3 yrs, 13F/14M) were exposed to progressive heat stress in a controlled environmental chamber during minimal activity. Progressive heat stress for the determination of critical environmental limits comprised either (1) constant dry-bulb (Tdb) temperature at 34°C with progressively increasing water vapor pressure (Pa) by 1 mmHg every 5 minutes (Pcrit trial), or (2) constant Pa at 12 mmHg with progressively increasing Tdb by 1°C every 5 minutes (Tcrit trial). Critical environmental limits in hot-dry environments were higher in young compared to middle aged (49.3±2.3 °C vs. 45.4±4.0 °C; p = 0.002) and older adults (49.3±2.3°C vs. 43.2±4.0°C; p < 0.001), but were not different between middle aged and older adults (45.4±4.0 °C vs. 43.2±4.0°C; p = 0.125). Critical environmental limits in warm-humid conditions were lower in older adults compared to young (23.1±6.1 mmHg vs 31.7±1.5 mmHg, p < 0.001) and middle aged (23.1±6.1 mmHg vs 29.0±5.1 mmHg, p = 0.004), but were not different between the young and middle aged (31.7±1.5 mmHg vs 29.0±5.1 mmHg, p = 0.220). Age was correlated with critical environmental limits in Tcrit (R2 = 0.34; p < 0.001) and Pcrit (R2 = 0.51; p < 0.001) trials based on linear and curvilinear regression, respectively. Critical environmental limits for middle aged adults performing minimal activity in warm-humid and hot-dry environments are intermediate to young and older adults. These data demonstrate an age-related decline in critical environmental limits that can be characterized by linear decline in hot-dry environments and by curvilinear decline in warm-humid environments. Supported by NIH Grant R01 AG067471. 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.