bluuebunny/crossref_metadata_2025 huggingface dataset:
Addressing underrepresentation in physiology research through internship opportunities
Authors: Barnett Vincent , Wu Steven , Metzger Joseph , Anderson Lisa
Published: May 2023

A challenge in the undergraduate physiology landscape is that some students who are underrepresented in the biomedical sciences are not aware of or are unable to take advantage of laboratory research opportunities. This is unfortunate because lab research can provide students with unique skill sets that are beneficial for future success, whether the students remain in research or move on to other careers. These skills include opportunities for critical thinking, improvement of oral and written communication skills, development of teamwork and leadership skills, learning about ethics in biomedical decision making and enhancement of digital literacy among others. As a program that sponsors an undergraduate Human Physiology major that has been successful in attracting underrepresented students (>40% students of color and >60% female) for a major Land-grant university, we challenged ourselves to consider how we might help our students make the most of their physiological interests and potentially improve the demographics of representation in our discipline. Starting in the summer of 2020, a group of faculty began a series of meetings to define an undergraduate program that would attract underrepresented students to lab-based internships, minimize the need for outside work by providing stipends and nurture their academic progress through informal student-faculty interactions. Though delayed by the Covid-19 pandemic, this framework has been used to initiate two new outreach programs. In the summer of 2021, we used this framework to initiate an American Heart Association sponsored research internship opportunity for 3rd and 4th year students. This program which we have named UPRIME is the focus of another abstract at this meeting. The INPUT (INtegrative biology and Physiology Undergraduate Training) program was started in fall of 2022. The program is internally supported and targets 1st and 2nd year undergraduates who represent populations that have been underrepresented in biomedical sciences. These students will be provided laboratory research experiences coupled with opportunities for educational support. A stipend of $3000 per student per semester is offered with the prospect of renewal dependent on a post-semester review. A cohort of six students were selected from a campus wide solicitation for applications into the inaugural INPUT class. These students will begin their projects in January 2023. We look forward to contributing to the scientific growth and development of these students. Perceptions of lab-based research and academic progress will be tracked along with career aspirations as the program progresses.

Department of Integrative Biology and Physiology, University of Minnesota Medical School

This is the full abstract presented at the American Physiology Summit 2023 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.
In vitro differences analysis in proliferation and drug sensitivity of tumor-associated fibroblasts from different regions of FDG metabolism to non-small-cell lung carcinoma
Authors: Hu Yiyi , Jian Shaojie , Yang Weihua , Wu Zhifang
Published: May 2023

Objective: 18F-FDG PET can directly reflect the glucose metabolism level of cells from the molecular level. Tumor-associated fibroblasts, as the natural physiological barrier of tumors, support and protect the survival of non-small cell lung cancer cells. This study will further observe the differences in the supporting effects of CAFs from different regions of 18F-FDG PET metabolism on cancer cells. Methods: Biopsy tissues were collected from PET/CT patients diagnosed with NSCLC for the first time in the Department of Nuclear Medicine, The First Hospital of Shanxi Medical University. The locations of puncture were all selected in areas with high metabolism of tumor. Primary CAFs were cultured by tissue adhesion method. A549 acts as EGFR (-) tumor cells, while PC9 acts as EGFR (+) tumor cells. CAFs conditional medium was collected to induce the culture of A549 and PC9 cells, labeled as A549high/low and PC9high/low, respectively. CCK was used to measure cancer cell proliferation rate, Transwell was used to measure cancer cell invasiveness, and scratch assay was used to measure cancer cell migration. The cells were treated with cisplatin and gefitinib respectively to observe the resistance of the cells. Results: Tissues of two NSCLC patients with SUVmax were 1.25 and 11.15, respectively. The conditioned medium induced cancer cells for 48 hours. CCK (48h) results showed that SUVhigh-derived CAFs could promote the proliferation of two types of cancer cells more than SUVlow-derived CAFs. The wound healing experiment showed that A549high had completed the healing at 72h, followed by low metabolism area, and A549 was the worst. The results for PC9 cells were similar to those for A549. Transwell experiment showed that PC9high/ low showed obvious difference in invasiveness at 24 hours, and the difference was more significant at 48 hours. A549 also showed difference in invasiveness, but the difference was relatively weak. When the corresponding cells were further treated with cisplatin or gefitinib, the proliferation rate of A549high/low cells was significantly different in the gradient range of high cisplatin concentration, while the proliferation rate of PC9high/low cells was significantly different in the low-medium gefitinib concentration. Conclusion: The regions of FDG metabolism difference shown in PET support the reverse warburg effect. As a physiological barrier to tumors, CAFs is one of the key factors that promote the occurrence, metastasis and drug resistance of lung cancer.

National Natural Science Foundation of China (Grant number:81971655)

This is the full abstract presented at the American Physiology Summit 2023 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.
Alveolar macrophage-derived secretory autophagosomes exacerbate inflammation in lipopolysaccharide-induced acute respiratory distress syndrome
Authors: Xu Xinyi
Published: May 2023

Background: Acute respiratory distress syndrome (ARDS) has a high incidence among patients in intensive care units. Extracellular vesicles and particles released from activated alveolar macrophages (AMs) contribute to ARDS-associated lung injury; however, the mechanisms underlying the inflammatory process remain unclear. Purpose: This study investigated the effects and the mechanisms through which AM-derived secretory autophagosomes (SAPs) contribute to ARDS-associated lung injury. Methods: SAPs were isolated from cell culture supernatants of AMs treated or untreated with lipopolysaccharide (LPS) and intratracheally injected to determine whether SAP exacerbated lung injury in mice with ARDS. The SAP proteome was analysed using mass spectrometry. Lung fibroblasts were treated with SAPs and collected for transcriptome sequencing. A transwell assay was conducted to study the chemotactic activity of fibroblasts induced by SAPs. Results: We found that AMs contributed to ARDS-associated lung injury by releasing a novel type of pro-inflammatory vesicles named SAPs, which were characterised as double-membraned vesicles approximately 200 nm in diameter and light-chain-3 expression. Proteomic analysis of SAPs and gene ontology (GO) enrichment analysis revealed that LPS-SAPs contain several differentially expressed proteins involved in effecting an inflammatory response, including interleukin (IL)-1β. We confirmed this result by quantifying IL-1β in SAPs using ELISA. Moreover, administering SAPs from LPS-stimulated macrophages to mice with ARDS exacerbated lung injury, whereas IL-1 receptor antagonist (IL-1RA) pre-treatment significantly ameliorated SAP-induced lung injury. In addition, we conducted transcriptome sequencing of lung fibroblasts treated with SAPs to explore the effect of SAPs on fibroblasts in ARDS, which demonstrated that the expression of several chemokines (CXCL2, CXCL15, and so forth) significantly increased with SAP stimulation. Furthermore, the transwell assay indicated that SAPs could enhance the chemotactic activity of fibroblasts, suggesting that SAPs may exacerbate inflammation in ARDS by promoting neutrophil or monocyte recruitment. Conclusion: This is the first study to show that AM-derived SAPs contribute significantly to ARDS by secreting pro-inflammatory cytokines and promoting inflammatory cell recruitment by activating fibroblasts, which may be beneficial for therapeutic development of ARDS.

National Natural Science Foundation of China (Grant numbers 81870066, 81670074, 81930058, 82270083 and 81971888), Six Talent Peaks Project in Jiangsu Province(Grant numbers TD-SWYY-003), and Social Development Specifc Projects of Jiangsu Province [Grant number BE2020786].

This is the full abstract presented at the American Physiology Summit 2023 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.
Dicarbonyl Stress Aggravates De Novo Fatty Acid Synthesis of Renal cells of Diabetes Mellitus via SREBP-1 /LDL-R Axis
Authors: Chen Eugene Chang-Yu
Published: May 2023

Introduction & Objectives: In diabetic patients, the excess blood glucose is autooxidized to produce methylglyoxal (MG), eliciting dicarbonyl stress, alteration of cellular proteins. MG was reported to play the role in the pathogenesis of renal microvascular complications. The storage of lipid droplets in nonadipose tissues is called ectopic lipid accumulation, which would induce cellular dysfunction. Literature indicated that renal lipid accumulation is associated with diabetic nephrodamage. Sterol regulatory-element binding proteins (SREBPs) regulate lipid homeostasis and cellular metabolism by controlling the expression of genes required for the uptake and synthesis of fatty acid, cholesterol, triglycerides. Considering MG to be the precursor of advanced glycation end products, whether the elevated dicarbonyl stress in DM patients can lead to renal lipotoxicity is still unclear. The aim of this project is to investigate the mechanisms of MG induced renolipotoxicity. Hypothesis: MG dysregulates fatty acid homeostasis in renal tubular cells to elicit lipotoxic complications with DM. Materials & Methods: In vitro NRK52E renal tubular cells and in vivo high-fat-diet induced diabetic mice models were treated with MG to verify this hypothesis. The 3D live cell imaging and Nile red staining were used to confirm the lipid deposition in the renal cells. The signaling proteins related to MG-induced fatty acid homeostasis were investigated by Western blot and immunohistochemistry. The renal lipotoxicity was analyzed by flowcytometry in vitro and hematoxylin-eosin stain in vivo. All data were statistically analyzed by the one-way AVOVA and the significance of confidence level was p< 0.05. Results: In vitro, severe lipid droplet deposition was found in the MG-treated renal tubular cells as revealed by the 3D live cell imaging. MG activated the SREBP1, resulting in stimulated expression of key regulators of fatty acid synthesis and LDLR-mediated lipid uptake. In parallel, in vivo fatty kidney and associated pathological severity in tubular cells under MG treatment were also evidenced. Conclusions: Our studies have revealed the molecular mechanism of reno-lipotoxicity caused by dicarbonyl stress in DM. Suggestively, to target on such early dicarbonyl stress may become a useful future therapeutic strategy for clinical treatment of delaying diabetic kidney disease.

This research received funding from the Ministry of Science and Technology, Taiwan.

This is the full abstract presented at the American Physiology Summit 2023 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 role of type I interferon on trisomy 21 endothelial angiogenesis
Authors: Frauenpreis Andrew , Hoarau Antony , Bhattacharya Soumyaroop , Glass Ian , Deutsch Gail , Mariani Thomas , Al Alam Denise , Danopoulos Soula
Published: May 2023

Rationale: Down syndrome (DS), resulting from Trisomy 21 (T21), is the most common chromosomal disorder worldwide. Cardiopulmonary complications are a leading cause of morbidity and mortality in DS. Pulmonary disorders include pulmonary hypertension and pulmonary capillaritis, which can result from a dysregulated lung endothelium. One of the major pathways consistently activated in DS is the type I interferon (IFN-I) pathway. High IFN-I inhibits VEGF induced development of capillary like structures, thus playing an anti-angiogenic role. Therefore, we aim to characterize the effects of IFN-I on T21 and euploid iPSC-derived endothelial cells (iPSC-ECs). Methods: Endothelial cell populations from single cell sequencing data of age matched T21 and Non-T21 prenatal lungs were carefully analyzed. Four iPSC lines were derived from age and sex matched T21 and non-T21 human fetal lung fibroblasts and used for endothelial cell differentiation using standardized kits and protocols from Stem Cell Technologies. FACs analysis confirmed endothelial cell purity and differentiation success: CD31+CD34+CD144+CD45-. For angiogenesis assays, endothelial cells were plated onto Cultrex in Ibidi angiogenesis 96-well plates with varying concentrations (0 to 104 pM) of IFNβ for 24 hours. Phase contrast images were taken with a 2.5X lens and analyzed in FIJI with the polygon shape tool to measure continuous mesh areas (CMA), defined here as a continuous endothelial cell layer undisrupted by branching structures. Results: Pathway analysis from our scRNAseq data demonstrated an upregulation of the IFN-I pathway across T21 endothelial clusters. T21 and non-T21 iPSC lines exhibited markers of pluripotency (OCT4, NANOG, SOX2, LIN28) and successfully generated pure populations of endothelial cells (~98% CD31+CD34+CD144+CD45-) by passage 2. Quantification demonstrated that at baseline T21 iPSC-ECs consistently had a significantly larger mean CMA than that of non-T21 iPSC-ECs (p< 0.01, n=4). High concentrations of IFN treatment (104 pM) resulted in an increased CMA in non-T21 cultures (p=0.14; n=4), trending towards baseline T21 cultures (p=0.28, n=4). Additionally, we observed a significant increase in the CMA of T21 cultures treated with 104 pM IFNβ (p=0.04, n=4). Conclusion: Our data suggest decreased angiogenesis in T21 iPSC-ECs may be caused by hyperactive IFN-I signaling. Further studies are needed to determine the mechanisms by which IFN-I regulates angiogenesis in T21 lungs.

NIH/NHLBI/OD HL155104-01A1, NIH/NHLBI HL141856, NIH/NHLBI R21HL165411-01, NIH/NICHD 2R24HD000836-52

This is the full abstract presented at the American Physiology Summit 2023 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.
Constitutive knock-in of MnSODK68R causes dilated cardiomyopathy and senescence in mice
Authors: Schell Joseph , Chocron E. Sandra , Wei Sung-Jen , Zhang Jun , Jiang Haiyan , Horikoshi Nobuo , Gius David
Published: May 2023

The mitochondrial superoxide dismutase (SOD2 or MnSOD) is an essential enzyme for managing oxidative stress, particularly by removing the highly reactive superoxide generated during the normal functioning of the electron transport chain. The activity of MnSOD is regulated post-translationally by acetylation, specifically at lysine 68. The deacetylated form of MnSOD is catalytically active, and it has been shown that the deacetylation mimic, MnSODK68R in which lysine 68 has been replaced with arginine, has upregulated dismutase activity in MCF7 and T47D human breast cancer cells. Overexpression of MnSOD has been shown to increase lifespan and protect against oxidative stress in the aging heart. We investigated a MnSODK68R knock-in mouse with ubiquitous expression of the mutant enzyme and expected similar effects as the MnSOD overexpressing mice. However, we have found that MnSODK68R homozygous knock-in mice develop dilated cardiomyopathy and have significantly decreased ejection fraction as evidenced by echocardiography at a young age. These mice also exhibit lower blood pressure compared to wild-type mice. Strikingly, these mice exhibit higher body weight, with increased lean mass and food consumption. Mitochondria isolated from MnSODK68R knock-in mouse hearts showed higher respiratory capacity than WT counterparts. Biochemical analysis revealed increased lipid peroxidation, oxidized peroxiredoxin and senescence markers, possibly indicative of a premature aging phenotype. We conclude that MnSOD constitutive function upregulation may produce a sustained increase in hydrogen peroxide levels that could cause senescence and lead to dilated cardiomyopathy.

This research was funded by NCI grant R01CA152601 and, R01CA214025, and the Cancer Prevention and Research Institute of Texas grant number RR20012. JS is supported by T32 AG 021890.

This is the full abstract presented at the American Physiology Summit 2023 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.
Deletion of the Acid-Sensing Ion Channel 1a Gene Leads to Age-Related Hypertension in Male but not Female Mice
Authors: Garcia Selina , Jernigan Nikki
Published: May 2023

Acid-sensing ion channel 1a (ASIC1a) is a proton-gated cation channel that conducts both Na+ and Ca2+ in the cell. Studies have shown that ASIC1a is expressed in smooth muscle and endothelial cells of various vascular beds. Previously, we have shown that ASIC1a contributes to pulmonary hypertension and pulmonary arterial vasoconstrictor reactivity. Additionally, we recently discovered that inhibition of ASIC1a significantly reduced endothelial-dependent vasodilation in mesenteric arteries leading us to question whether ASIC1a contributes to the regulation of systemic mean arterial blood pressure (MABP). The incidences of cardiovascular disease are higher in males than females at a young age, however, this difference is largely diminished in post-menopausal females. Therefore, we aim to determine the age- and sex-related contribution of ASIC1a to cardiovascular homeostasis. We hypothesize that the genetic deletion of Asic1a will lead to age-related systemic hypertension in both male and female mice. MABP and heart rate (HR) were measured using radiotelemetry in conscious young (6-8 months) and aged (>15 months), male and female, Asic1a +/+ and Asic1a -/- mice. We found that Asic1a -/- male mice develop age-related systemic hypertension and increased HR compared to aged-matched Asic1a +/+ males. However, there were no differences in MABP in aged female mice and HR was significantly lower in Asic1a -/- mice compared to age-matched Asic1a +/+ mice (p=0.0008). To determine if Asic1a is contributing to age-induced systemic hypertension through a vascular or central regulation, norepinephrine and epinephrine levels were measured with an ELISA in young and aged Asic1a +/+ and Asic1a -/- mice. Although there was not a significant change in epinephrine between genotypes, norepinephrine was significantly increased in aged Asic1a -/- compared to young Asic1a -/- (p<0.0001) and aged-matched Asic1a +/+ (p<0.0001) mice indicating that the increased MABP is associated with elevated sympathetic nerve activity. Age increased norepinephrine levels in aged female mice, however, there was no statistical difference between genotypes. Together this data shows a sex-specific role for Asic1a to regulate age-induced systemic hypertension. Future studies will define the centrally-mediated mechanism by which Asic1a regulates MABP.

Supported by National Heart, Lung, and Blood Institute Grants R01 HL-111084 to N.L. Jernigan and T32 HL-007736 to T.C. Resta

This is the full abstract presented at the American Physiology Summit 2023 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.
Endothelial Piezo1 channel controls cerebral blood flow
Authors: Harraz Osama , Ippolito Michael , Senatore Amanda , Willemse Luc
Published: May 2023

Cerebral blood flow is controlled to meet the ever-changing demands of active neurons. Brain capillaries are equipped with sensors of neurovascular coupling agents released from neurons/astrocytes onto the outer wall of a capillary. While capillaries can translate external signals into electrical and Ca2+ changes, control mechanisms from the lumen are less clear. The continuous flux of red blood cells and plasma through narrow-diameter capillaries imposes mechanical forces on the luminal (inner) capillary wall. We have recently discovered that the mechanosensitive Piezo1 channels operate as mechanosensors in CNS capillaries. Whether—and if so how—Piezo1-mediated mechanosensation regulates CBF is not known. Using genetically engineered mice in which endothelial Piezo1 is ablated (Piezo1EC-KO) or mutated (Piezo1EC-mut), we assessed channel activity and CBF. We provide evidence that Piezo1 plays an important role in CBF control and profoundly affects functional hyperemia during somatosensory stimulation. These observations are of profound significance for the control of brain blood flow in health and in disorders where hemodynamic forces are disrupted, such as hypertension.

The American Heart Association (20CDA35310097), the National Institute of General Medical Sciences (P20GM135007), the Totman Medical Research Trust, the Larner College of Medicine, University of Vermont, and the Cardiovascular Research Institute of Vermont.

This is the full abstract presented at the American Physiology Summit 2023 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.
Dorsal motor vagal neurons can suppress heart rate in mice
Authors: Kauffman Lily , Conley Nicholas , Campbell John
Published: May 2023

The dorsal motor nucleus of the vagus (DMV) is a functionally heterogeneous vagal motor region which controls a variety of digestive and metabolic functions but also innervates the heart, where its role in controlling heart rate is less clear. We therefore chemogenetically activated DMV neurons in awake behaving mice while monitoring heart rate. To selectively activate DMV neurons, we injected an adeno-associated virus (AAV) which expresses the excitatory chemogenetic receptor, hM3Dq (8 injections, 40nl each), only after recombination by both Cre and Flp recombinases, into the DMV of Chat-Cre::Phox2b-Flp mice. Several months later, we injected the hM3Dq ligand clozapine N-oxide (CNO; 1mg/kg) via intraperitoneal injection (n=2 females, 3 males; mean age ± S.D., 32 ± 2 weeks) to activate hM3Dq+ DMV neurons while measuring heart rate via a non-invasive ECG system (ECGenie). We measured heart rate 20 minutes prior to CNO and 0, 20, 40 minutes and 1, 2, 6, 8, 24 hours later. CNO administration significantly but reversibly decreased heart rate (mean ± standard deviation, S.D.: 20min before CNO, 705 ± 15 bpm; 40min after CNO, 536 ± 86 bpm, p=0.0271; 24hr after CNO, 727 ± 25 bpm, p=0.7347; one-way ANOVA, all timepoints, F1.660, 6.638=10.31; Dunnet's post-hoc test, p=0.0107). In order to identify the specific neurons responsible, we repeated these studies in Calb2-Cre::Chat-Flp mice (n=2 females, 3 males; mean age ± S.D., 29 ± 2 weeks) to target Calb2+ DMV neurons, a recently identified DMV molecular subtype. However, in striking contrast to what we observed when activating DMV neurons generally, administering CNO to activate Calb2+ DMV neurons specifically did not significantly affect heart rate (mean ± S.D.: 20min before CNO, 691 ± 69 bpm; 40min after CNO, 718 ± 31 bpm, p=0.6787; 24hr after CNO, 710 ± 54 bpm, p=0.4701; one-way ANOVA, all timepoints, F2.911, 11.65=0.6277; Dunnet’s, p=0.6069). A higher dose of CNO (3.5mg/kg) also had no effect on heart rate in Calb2-Cre::Chat-Flp mice (data not shown). Together, our studies indicate that DMV neurons are capable of suppressing heart rate and that the underlying neurons likely do not express Calb2. Uncovering the DMV’s role in heart rate will expand our understanding of how this clinically relevant metric, associated with a host of cardiovascular disorders, is controlled.

Ingrassia Family Echols Scholars Research Grant and Schwager Summer Research Scholarship to L.S.K.; ADA Pathway to Stop Diabetes Award 1-18-INI-14 and NIH grant HL153916 to J.N.C.

This is the full abstract presented at the American Physiology Summit 2023 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.
Electrophysiological characteristics of leptin receptor-expressing neurons in the dorsomedial hypothalamus
Authors: Pryor Jack , Simonds Stephanie
Published: May 2023

The adipocyte-derived hormone leptin acts at leptin receptor (LepR)-expressing neurons in the brain to regulate metabolic and cardiovascular functions. LepR neurons in the dorsomedial hypothalamus (DMH) are required for leptin-induced feeding suppression, regulate brown adipose tissue thermogenesis and locomotor activity. We have previously identified these neurons as necessary for the hypertensive effects of hyperleptinemia in obesity. These neurons are heterogenous, with LepRs differentially co-expressed with metabolism-regulating peptides and receptors including, glucagon-like peptide 1 (GLP-1), agouti-related peptide (AgRP) and proopiomelanocortin (POMC). Variations in LepR neuron gene expression profiles may indicate differences in leptin responsiveness, function specificity and electrophysiological characteristics. Work presented here used in vitro visualized whole-cell patch clamp electrophysiology to characterise the electrophysiological properties of leptin-excited, leptin-inhibited, and non-responsive LepR neurons in the DMH of transgenic LepR-YFP mice. Whole cell current clamp recordings were obtained from 34 DMH LepR neurons and of these, bath application of 100 nM leptin excited 38% (n=13). Of some leptin excited LepR neurons, the effect was indirect via elevated spontaneous excitatory postsynaptic potential (EPSP) frequency (n=2). Of other leptin excited LepR neurons, membrane depolarisation was direct via the activation of one or more non-selective cation conductances (n=11). In two cases, leptin-induced sub and suprathreshold 'pacemaker like' oscillations in membrane potential. Of leptin-excited neurons 23% (n=3) of neurons expressed transient outward rectification ( ITR), 54% (n=7) expressed low-threshold t-type calcium conductances ( IT), 8% expressed instantaneous or anomalous inward rectification ( IAN) (n=1) and 15% expressed hyperpolarization-activated non-selective cation conductances ( IH) (n=2). Bath application of 100 nM leptin inhibited 15% of LepR neurons tested (n=5). these inhibitory membrane effects were postsynaptic and via the activation of one or more potassium conductances. Of leptin inhibited neurons 60% expressed ITR, 60% (n=3) expressed IT, 40% (n=3) expressed IAN and 40% (n=2) expressed IH. In 47% of neurons tested, bath application of leptin did not have any clear inhibitory or excitatory membrane (n=16). Of these non-responsive neurons 50% (n=8) expressed ITR, 44% (n=7) expressed IT, 44% (n=7) expressed IAN and 25% (n=4) expressed IH. Work presented highlights the heterogeneity of DMH LepR neurons and further indicates the existence of function-specific subpopulations.

This is the full abstract presented at the American Physiology Summit 2023 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.
Phase 3 Anticancer Agent, RRx-001, Ameliorates Hypoxia-Induced Pulmonary Hypertension
Authors: Cabrales Pedro , Reid Tony , Caroen Scott , Oronsky Bryan
Published: May 2023

Background: The hallmark features of pulmonary artery hypertension (PAH), for which hypoxia triggers, are vascular remodeling, elevated pulmonary blood pressure, oxidative stress, and right ventricular hypertrophy. RRx-001 is a minimally toxic Phase 3 anticancer agent with anti-oxidative, anti-inflammatory, nitric oxide-donating, and anti-proliferative properties. This study aimed to investigate the effect of RRx-001 on intermittent hypoxia-induced PAH in rats. Methods: Male Wistar rats (180-220 g) were divided into four groups (n=6 per group): normoxic control, hypoxic with vehicle treatment (2 weeks breathing an atmosphere containing 10% oxygen), hypoxic treated with oral endothelin-1 receptor inhibitor, bosentan, 50 mg/kg per day for 2 weeks during hypoxia and one intravenous dose of 5mg/kg RRx-001 given the day before the start of the hypoxia. After sacrifice, hearts and lungs were removed and harvested for analysis. Results: Both RRx-001 and bosentan treated animals, separately and to a similar degree, significantly attenuated hypoxia-induced increases in right ventricular systolic pressure and right ventricular hypertrophy compared to control animals. RRx-001 and bosentan, separately and to a similar degree, also significantly decreased pulmonary artery media thickness. RRx-001 treatment reduced vasocostriction of pulmonary arterioles and the wall thickness/external diameter ratio of the pulmonary arteries compared to vehicle treated animals. Conclusions: RRx-001 reduces right ventricular systolic pressure and pulmonary vascular remodeling in a rat model of PAH, potentially making it a new therapeutic option for this disease. The combination of bosentan and RRx-001 will be attempted as a next step.

Commercial and private foundation grants

This is the full abstract presented at the American Physiology Summit 2023 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.
Stretch-induced mechanical stimulation effects on vascular smooth muscle contractility in aged resistance arteries
Authors: Mohajeri Amin , Padgham Samuel , Woodman Christopher , Trache Andreea
Published: May 2023

Age–related impairments of skeletal muscle resistance arteries are associated with alterations in vascular smooth muscle cell (VSMC) contractility. Aerobic exercise is an effective intervention for reversing the impacts of aging on vascular contractility. In addition, we have shown that arterial wall-stretch, induced by a short-duration increase in intraluminal pressure in cannulated soleus muscle feed arteries (SFA), attenuates age-related changes in VSM contractility. The mechanisms responsible for the beneficial effect of wall stretch on contractility are not fully understood. Purpose: VSMC respond to extracellular mechanical signals by dynamic remodeling of actin fibers and cell-matrix adhesions. In this study, we investigated the impact of in vitro cyclic stretch on attenuating the age–induced alterations in VSMCs contractility by evaluating changes in vinculin, as a marker for cell-matrix adhesions, and smooth muscle α-actin (SMα-actin) fiber formation. Methods: VSMC isolated from SFA of young (4 month) and old (24 month) male F344 rats were cultured on fibronectin–functionalized silicon membranes. Equibiaxial cyclic stretch (10%) at 0.25 Hz frequency was applied to both young and old cells for 2 or 5 min. Static condition (no stretch) was used as control. At the end of the study, cells were fixed in their stretched or static state with 2% paraformaldehyde and stained for SMα-actin and vinculin. Dual color confocal imaging was performed using Olympus Fluoview 3000 microscope, and SlideBook software was used to analyze the data. Results: Young and old VSMC respond differently to stretch-induced mechanical stimulation. Results showed an increase in actin stress fibers formation in old VSMC for both time points when compared to young cells or old cells at rest. Similarly, vinculin recruitment at cell-matrix adhesion was increased in old VSMC. No differences were found between young and old cells in the static condition for any of the proteins. Conclusion: Taken together, these data show that stretch-induced mechanical stimulation increases actin stress fiber and integrin-based adhesions contributing to improved aged VSM cells contractility.

Sydney and J.L. Huffines Institute for Sports Medicine and Human Performance

This is the full abstract presented at the American Physiology Summit 2023 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.
Gestational high altitude long term hypoxia and impact of oxidative stress on ryanodine receptor activity in pulmonary arterial myocytes of fetal sheep
Authors: Khalil Brandon , Abd-Allah Muhammad , Moral Elena , Romero Monica , Juarez Rucha , Zhang Lubo , Puglisi Jose , Wilson Sean
Published: May 2023

High altitude exposure reduces the oxygen tension in ambient air. The resultant hypoxia induces oxidative stress and causes vasoconstriction of the blood vessels within the pulmonary vasculature that can result in pulmonary hypertension. Previously we found that high altitude gestation deregulated Ca2+ spark activity in fetal pulmonary arteries, which is due to local ryanodine receptor (RyR) activation. These Ca2+ sparks are thought to be coupled to vasodilatory pathways and are important to vasodilation at birth, Furthermore, RyR activity is affected by the redox-status of the protein. Thus, the elevated oxidative stress in pulmonary arteries due to high altitude exposure may underlie the dysregulation in Ca2+ spark activity. We hypothesized that high altitude mediated long term hypoxia alters the impact of oxidative stress on Ca2+ spark activity. This hypothesis was examined in pulmonary arterial (PA) myocytes from low altitude (335m) and high altitude acclimatized fetal sheep (~3,800m for <100 days). Intracellular Ca2+ sparks were recorded within the myocytes of smooth muscle cells using line-scan confocal imaging of the Ca2+ indicator Fluo-4. Oxidative stress was elevated with acute exposure to tert-butyl H2O2 (TbH2O2) or reduced with the antioxidant N-Acetyl-Cysteine (NAC). Ca2+ spark activity and spatial-temporal properties were analyzed with automated custom designed software (SparkLab). Increased oxidative stress with TbH2O2 failed to influence Ca2+ spark activity independent of altitude. Interestingly, NAC preferentially reduced Ca2+ spark activity in myocytes of normoxic pulmonary arteries. These data suggest that RyR activity and resultant Ca2+ sparks in high altitude fetal sheep are resistant to acute changes in cellular redox status.

NIH R01HL155295 and R01HL149608, NSF Grant MRI-DBI 0923559 and the Loma Linda University School of Medicine

This is the full abstract presented at the American Physiology Summit 2023 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.
Do cytochrome P450 2C9 pathways contribute to the cerebrovascular response to small muscle exercise?
Authors: Mixon Chris , Matney Jacob , Buelow Alexander , Skillett Sarah , Ashley John , Song Jiwon , Black Christopher , Pereira Hugo , Kellawan J
Published: May 2023

Cytochrome P450 2C9 (CYP450) contributes to regulation of cerebral blood flow in animal models, however, the involvement of CYP450 in human cerebrovascular control is under researched. To this effect, small muscle exercise has been utilized as a model to evaluate cerebral flow in humans, but whether CYP450 contributes to that response is unknown. PURPOSE: To determine if CYP450 contributes to cerebrovascular response during small muscle exercise. METHODS: 16 healthy young adults (10 females tested only in the first 5 days of their menstrual cycle) participated in a familiarization visit followed by 2 experimental visits separated by ≥72hrs. Participants received either a microcrystalline cellulose placebo (PLA 250mg) or the CYP450 inhibitor fluconazole (FLZ 150mg) in a single-blind, randomized, crossover design. After ingestion, participants rested for 120 minutes prior to the experiment. After which, mean arterial pressure (MAP, mmHg, finger photoplethysmography) and middle cerebral artery velocity (MCAv, cm/s, Transcranial Doppler) were measured continuously for 5 minutes of supine rest followed by 5 minutes of dynamic hand grip exercise (contraction/relaxation cycle 1:2 seconds) at heart level at resistance 20% of their maximal voluntary contraction. Cerebrovascular conductance index was calculated as CVCi = MCAv/MAP (cm/s/mmHg). RESULTS: Data was averaged as 3 second intervals to match the contraction rate and presented as change (Δ) from rest to exercise, reported as mean ± SD. All values were not different between treatments at steady state exercise (MAP PLA Δ 10.9±5.5 vs. FLZ Δ 10.4±3.3 mmHg, p = 0.88, MCAv PLA Δ 0.9±7.7 vs. FLZ Δ 1.2±4.7 cm/s, p = 0.88, CVCi PLA Δ -0.07±0.06 vs. FLZ Δ -0.06±0.06, p = 0.34). Interestingly, at exercise onset (~ 18s or first 6 contraction cycles) MCAv response was blunted with FLZ (PLA Δ 5.2±4.8, FLZ Δ 2.9±3.9 cm/s, p = 0.03, d = 0.51). This attenuation was not due to a change in MAP (PLA Δ 1.2±3.0, FLZ Δ 2.2±4.8 mmHg, p = 0.2, d = -0.25). Thus, attenuation of the MCAv in FLZ was due to a reduction in CVCi response (PLA Δ 0.04±0.04, FLZ Δ 0.009±0.04 cm/s/mmHg, p = 0.003, d = 0.8). CONCLUSION: Our results indicate that CYP450 does not affect MCAv, CVCi, or MAP once steady state is achieved during small muscle exercise. However, CYP450 inhibition attenuates vascular response at exercise onset. Therefore, CYP450 contributes to the cerebrovascular response to small muscle mass exercise, however, compensatory vascular mechanisms can overcome CYP450 inhibition indicating CYP450 has a significant yet non-obligatory role in cerebrovascular regulation during exercise in humans.

This is the full abstract presented at the American Physiology Summit 2023 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 biological sex on the acute flow-mediated dilation response to maximal exercise in healthy older adults
Authors: Lapierre Stephanie , Kim Jin-Su , Beckers Alexander , Riesco Eléonor , Soonhuae Chatchamarn , Sakarya Yasemin , Handberg Eileen , Leach Dana , Christou Demetra
Published: May 2023

Flow-mediated dilation (FMD) is a noninvasive measure of endothelial function and is a predictor of future cardiovascular disease risk. Previous studies have shown that biological sex modulates the FMD response to acute submaximal exercise in healthy older adults. However, the FMD response to maximal exercise has not been investigated in older adults; thus, whether sex impacts this response remains unknown. Therefore, the purpose of this study was twofold: 1) to investigate the FMD response to maximal exercise in older adults and 2) to test the hypothesis that FMD following maximal exercise will change differently in healthy older men compared with women. We studied twenty sedentary adults (50% women, age: 66±1 vs. 66±1 yrs, men vs. women, mean±SE, P>0.9), free of major clinical disease, who were not on hormone replacement therapy. Women were all postmenopausal. Vascular function was assessed before and after maximal exercise, based on a modified Balke treadmill test. FMD was assessed in response to 5 min forearm occlusion at 250 mmHg using brachial artery ultrasonography. We found pre-occlusion brachial diameter was larger in older men compared with women before (5.04±0.18 vs. 4.27±0.09 mm, P=0.002) and after maximal exercise (4.75±0.16 vs. 3.98±0.12 mm, P=0.001), but there was no sex × time interaction (P=0.1). Peak shear rate was significantly lower in older men compared with women before exercise (1852±81 vs. 2265±129 sec-1, P=0.01) and did not change after maximal exercise in either group (P=0.2). FMD was not significantly different in older men compared with women (P=0.1) before exercise and significantly increased following maximal exercise in both older men (3.84±0.66 vs. 6.55±1.27 %, pre- vs. post-exercise, P=0.009) and women (2.32±0.61 vs. 5.65±1.07 %, P=0.002), but the response was not impacted by sex (P=0.6 for sex × time interaction). When FMD was allometrically scaled to assess the potential effect of pre-occlusion diameter, our findings remained unchanged. Time to peak dilation was delayed in older men and women similarly following maximal exercise (51±2 vs. 75±7 and 56±7 vs. 85±7 sec, pre- vs. post-exercise, P≤0.02; P=0.7 for sex × time interaction). In conclusion, this investigation demonstrated for the first time in older adults that: 1) FMD is enhanced following maximal exercise and 2) biological sex does not influence the FMD response to maximal exercise

This work was supported by National Institute of Aging grant AG063143-01.

This is the full abstract presented at the American Physiology Summit 2023 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.
High sugar diet-induced insulin resistance in glia impairs axonal clearance after injury by downregulating Draper signaling
Authors: Alassaf Mroj , Rajan Akhila
Published: May 2023

Obesity significantly increases the risk for developing neurodegenerative disorders, yet the precise mechanisms underlying this connection remain unclear. Defects in glial phagocytic function is a key feature of neurodegenerative disorders, as delayed clearance of neuronal debris can result in inflammation, cytotoxicity, secondary neuronal death, and poor nervous system recovery. Whether or how diet-induced obesity disrupts glial phagocytosis is unknown. Here, using a Drosophila diet-induced obesity model, we show that subjecting adult flies to a chronic high sugar diet (HSD) treatment delays the clearance of degenerating axons by causing glial insulin resistance. We find that HSD downregulates the basal and injury-induced expression of the glia-associated phagocytic receptor, Draper. Genetically inducing Insulin release from the Insulin producing cells (IPCs) phenocopies the HSD-induced Draper downregulation and insulin resistance, while attenuating insulin release from the IPCs rescues HSD-induced Draper downregulation and insulin resistance. Significantly, we show that genetically stimulating Phosphoinositide 3-kinase (PI3K), a downstream effector of Insulin receptor signaling rescues HSD-induced glial defects. Together, we provide mechanistic insights into how HSD alters glial phagocytic function in the adult brain.

This is the full abstract presented at the American Physiology Summit 2023 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.
Targeted pharmacological inhibition of neuraminidase-3 ameliorates vascular dysfunction in diabetic mice
Authors: Foote Christopher , Ramirez-Perez Francisco , Jurrissen Thomas , Power Gavin , Morales-Quinones Mariana , Betancourt-Cortes Edgar , Lazo-Fernandez Yoskaly , Augenreich Marc , Manrique-Acevedo Camila , Padilla Jaume , Martinez-Lemus Luis
Published: May 2023

In type 2 diabetes (T2D), endothelial dysfunction and arterial stiffening play a significant role in the development of cardiovascular disease. A central mediator of vascular dysfunction is degradation of the endothelial glycocalyx, a semipermeable mechanosensitive structure that separates the endothelium from the flow of blood and shear forces associated with it. Neuraminidase, a sialidase that cleaves sialic acid from the terminal branches of glycoproteins and glycolipids, is implicated in glycocalyx degradation. However, its role in mediating vascular dysfunction in the setting of T2D remains relatively unexplored. Herein we tested the hypothesis that increased neuraminidase-3 (Neu3) activity impairs vascular function, while its targeted inhibition improves it in diabetes. In support of this hypothesis, we report that mice overexpressing Neu3 exhibit increased blood pressure and pulse wave velocity, indicative of increased arterial stiffness. Furthermore, we show that pharmacological inhibition of Neu3 for 28 days in diabetic ( i.e., db/db) mice (vs. vehicle control) resulted in reduced pulse wave velocity, with no change in blood pressure. Neu3 inhibition also reduced stiffness in aortic explants, as assessed via atomic force microscopy. Excised arteries were also assessed for flow-mediated dilation and vascular stiffness using pressure myography. Arteries from diabetic mice treated with the Neu3 inhibitor had increased flow-mediated dilation and reduced incremental modulus of elasticity, indicative of improved endothelial function and reduced arterial stiffness. Collectively, these data support the hypothesis that Neu3 is a potential therapeutic target for the amelioration of vascular dysfunction in T2D.

National Institutes of Health grant: R01HL153264 to LM-L and JP

This is the full abstract presented at the American Physiology Summit 2023 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.
Framework for precision phenotyping of heart failure patients using clinical data at rest and exercise
Authors: Carlson Brian , Meyer Andrew , Ježek Filip , Jones Edith , Hua Xinwei , Hummel Scott , Tang Yida , Beard Daniel
Published: May 2023

Precision phenotyping of mechanistic differences between and within different types of heart failure is a valuable tool not only to understand the range of underlying cardiovascular dysfunction but to identify patients who could benefit from a targeted treatment or procedure. Our group previously has used standard clinical hemodynamic measures at rest coupled with a computational model of the cardiovascular system to identify differences between patients diagnosed with heart failure with preserved ejection fraction (HFpEF). Even though this effort has proven fruitful, many patients with HFpEF exhibit symptoms only during exercise. We hypothesize that incorporating exercise metrics into our approach will improve discrimination between HFpEF phenotypes. In this study we have expanded the pool of clinical data to include cardiopulmonary exercise testing (CPET) data and added to the complexity of our cardiovascular system model to simulate exercise. Data were collected prospectively from both Peking University Third Hospital and the University of Michigan and include measures from right heart catheterization (RHC) at rest and at exercise along with transthoracic echocardiography (TTE) at rest. The measures for each patient are used to identify our expanded cardiovascular systems model which now can inform parameters related to the strength of sarcomeric contraction in the left, septal and right ventricular walls, left and right atrial elastance in addition to predicting left ventricular and right ventricular cardiac power at rest and exercise. Based on the preliminary data acquired, we present a framework that can quantify underlying differences between HFpEF patients using unsupervised machine learning to find distinct HFpEF phenogroups, using clinical data both at rest and during exercise.

Michigan Medicine/Peking University Health Science Center Joint Institute for Translational and Clinical Research

This is the full abstract presented at the American Physiology Summit 2023 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.