bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endothelial Membrane Potential Changes are Required for Propagated Vasodilation
Authors: Woodsend Cian , Buckley Charlotte , Zhang Xun , Wilson Calum , Lee Matthew , McCarron John 
Published: May 2024

Introduction: The coordination of blood flow in response to localized increases in metabolic activity is vital for tissue function. This adaptive response typically involves the release of vasoactive factors leading to local vasodilation. This local vasodilation must propagate upstream to proximal feed arterioles and arteries to ensure a coordinated increase in blood flow and adequate tissue perfusion. But the mechanisms underlying such propagated vasodilation remain to be fully understood. This study aims to identify the conduction pathway(s) that facilitate this response. The hypothesis is that endothelial membrane potential changes are required for propagated vasodilation to occur. Methods: To dissect the pathways involved in propagated vasodilation, we employed micropuffng techniques to locally apply vasoactive agents to precontracted rat 2nd order mesenteric arteries. Using a 50um tip micropipette activators were applied against a flowing perfusate, to limit the action of the drug, and the precise site of activators determined by co-application of the fluorophore sulforhodamine. Vasodilator responses were recorded at the site of application and at intervals upstream from the application site. Results: Local application of the muscarinic receptor agonist, acetylcholine (ACh), evoked robust vasodilator responses that propagated upstream from the site of application. The propagation of vasodilation terminated at the site of removal of a 100uM wide strip of endothelial cells. A high-potassium solution, which induces depolarization and ‘clamps’ the membrane potential, also inhibited propagated vasodilation. In contrast, the nitric oxide donor, sodium nitroprusside did not initiate propagated vasodilation in arteries with an intact endothelium. Conclusion: Collectively, these results show that the endothelium serves as the primary signalling pathways for propagated vasodilation. Furthermore, our results highlight the necessity of endothelial cell membrane potential change in the initiation of this vasodilator signal. These insights reinforce the endothelium’s pivotal role in coordinating vascular function. British Heart Foundation. 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.
Recruitment of T-cells to the lung using an ex vivo co-culture paradigm
Authors: Ehrlich Alexis , Tobet Stuart 
Published: May 2024

Precision cut lung slices (PCLS) bridge a gap between in vivo and in vitro studies by maintaining anatomical organization with structural integrity and intercellular signaling pathways. Applications of PCLS have included the modeling of inflammatory lung diseases, metabolism studies, and drug development. In the lungs, immune responses are carried out by a network of T- and B- cells, the latter of which are resident. The limited resident T-cell population of the lung diminishes accurate representations of pathogen response capacity in PCLS. Addressing this, we set out to increase pulmonary T-cell populations ex vivo. We hypothesized that thymus and bone marrow-derived T-cells would work synergistically to populate the lung in co-culture experiments. A murine organotypic lung co-culture model was developed and characterized for tissue health and T-cell recruitment over 3 days ex vivo using adult neurobasal media with 4 mM glucose + 2% B27 supplement. Lung slices were cultured independently, with bone marrow, thymus, or both. Immune colonization of the lung was assessed using immunohistochemistry for CD3+ T-cells and ACK2+ cells. Cells were counted in alveolar and airway spaces after 3 days of culture. Co-culture of lung slices with bone marrow did not increase CD3+ immunoreactive T-cells while thymus co-culture increased CD3+ T-cells by 76% in the alveolar space and by 39% in the airway, relative to lung alone. When lung slices were cultured with bone marrow plus thymus, CD3+ T-cells increased by 206% in the alveolar space and by 251% in the airway, relative to the lung alone. Co-culture with thymus increased ACK2+ cells by 48% in the airway, while lung culture with both thymus and bone marrow, ACK2+ cells increased by 35% in the alveolar space and 85% in the airway, relative to the lung alone. These results suggest that the increased T-cell population corresponding with thymus and bone marrow co-culture could be a result of cell-cell interaction or the secretion of growth factors. Cell secretions or growth factor release could stimulate thymic secretion of T-cells or could stimulate T-cell proliferation in the lung, suggesting that co-culture with thymus and bone marrow can elicit a T-cell response ex vivo. Future studies will center around differentiating what drives T-cell population to be increased in lung co-cultures and what T-cell subsets are being recruited in PCLS co-cultures while analyzing their capacity for response to pathogens ex vivo. Anschutz Foundation Pandemic Preparedness Grant. 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.
Activin A Contribution to Diabetic Kidney Disease Injury and Effects of Activin A Antagonism In-Vitro
Authors: Learmonth Maya , Skaff Caroline , Snow Zachary K. , Bian Xiaohui , Hickson LaTonya 
Published: May 2024

Diabetic kidney disease (DKD) is the worldwide leader in end-stage kidney failure and has limited treatment options. Cellular senescence abundance and inflammation contribute to DKD pathogenesis. We previously demonstrated that activin A, an inflammatory mediator of pro-fibrotic kidney injury and cellular senescence, is increased in DKD and correlates with DKD injury and kidney function. We hypothesized that activin A contributes to DKD injury causing pro-fibrotic, pro-inflammatory, and cellular senescence effects in vitro, and that antagonism of activin A is achieved with follistatin. An in vitro model of DKD injury was applied with high-glucose (HG) and transforming growth factor-β (TGFβ) exposure for 24 hours in U-937-derived macrophages and renal epithelial (HK2) cells. Prior to exposure, U-937 cells were converted to M0 macrophages with phorbol myristate acetate (PMA). To examine the potential of reducing activin A release by DKD injured cells, follistatin, an activin A antagonist, was added to the media of cells at the time of injury for 24 hours. Additionally, an activin A neutralizing antibody was added to the collected supernatant of DKD injured cells. Activin A, senescence (p16), pro-fibrotic (collagen I), and pro-inflammatory (monocyte chemoattractant protein [MCP]-1, tumor necrosis factor [TNF]-alpha, interleukin [IL]-6) markers were measured through qPCR, ELISA (activin A), and immunofluorescence staining (activin A). DKD injury in renal epithelial cells increased protein expression of activin A, increased gene expression of activin A, p16, and collagen I, but did not significantly increase MCP-1 expression at 24 hour exposure (Figure 1). Furthermore, DKD injury led to increased activin A release in conditioned medium vs. control renal epithelial cells. Administration of follistatin reduced activin A release by renal epithelial cells. Application of neutralizing antibody reduced activin A levels in collected medium after cell injury. After DKD injury in U-937 derived macrophages, activin A gene expression was increased. Injured macrophages had increased gene expression of TNF-alpha and IL-6, demonstrating a pro-inflammatory phenotype. In conclusion, diabetic kidney injury increases activin A release, inflammation markers, and senescence markers in kidney cells and macrophages, therein contributing to downstream effects that further propagate disease. As shown, follistatin antagonism reduces activin A release by injured cells. Additional studies are needed to explore activin A as a promising therapeutic target and follistatin as a possible treatment in DKD. NIH 5TL1TR002380-07, AG076537, DK123492, DK109134. 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 Effect of Dietary Sodium and Potassium Consumption on Intestinal Permeability and its Relation to Blood Pressure, and Endothelial Function: A Pilot Study
Authors: Kaseman Kathryn , Lobene Andrea , Axler Michael , Lennon Shannon 
Published: May 2024

High sodium (HS) diets can reduce endothelial function (EF) and increase blood pressure (BP) while high potassium (HK) diets are shown to counter this effect. Furthermore, HS diets have also been shown to lead to gut dysbiosis, which is related to increased intestinal permeability (IP). However, the effect of HS diets on IP and whether the addition of HK can attenuate potential HS-induced changes to IP is unknown. Hypotheses: We hypothesized IP would increase on a HS diet and be mitigated by HK and that a higher IP would be related to elevations in BP and lower EF. Methods: Eleven healthy participants (5W/6M, age 32±8 yrs, BMI 23±1, BP 105±6/66±7 mmHg) consumed three 10-day diets of differing sodium and potassium content in randomized order: low sodium (LS)/low potassium (LK) (50mmol/65mmol), HS/LK (300mmol/65mmol), and HS/HK (300mmol/120mmol). On day 9 of each intervention, they collected their urine and wore an ambulatory BP monitor for 24-hr. On day 10, brachial artery flow-mediated dilation (FMD) was measured. Blood was collected and lipopolysaccharide-binding protein (LBP), a biomarker of IP and bacterial translocation, was measured by ELISA. Mixed design ANOVAs assessed sex differences in LBP, FMD, and BPs between diets. Simple linear regressions assessed relations between variables. Results: Twenty-four-hr urinary sodium excretion was higher on both HS diets compared to LS/LK diet (both p<0.01) and 24-hr urinary potassium excretion was higher on HS/HK compared to LS/LK and HS/LK diets (both p<0.01). LBP was different between diets (p<0.01), and there was a significant diet*sex interaction (p=0.02) where men had increased LBP compared to women on the HS/LK and HS/HK diets (both p<0.01). FMD was not different between diets (p=0.13) although men had a lower FMD compared to women after each diet (sex: p<0.01). Twenty-four-hr mean arterial pressure (MAP) was different between diets (p=0.047) as men demonstrated higher 24-hr MAP on the HS/LK diet compared to LS/LK diet (p=0.03) and lower MAP on the HS/HK diet compared to HS/LK diet (p=0.01). LBP was inversely related to FMD (r=-0.82, p<.01) and positively related to MAP (r=0.72, p<.01), 24-hr systolic BP (r=0.66, p=0.03), and 24-hr diastolic BP (r=0.66, p=0.03) on the HS/LK diet for all participants, but not the LS/LK or HS/HK diets. Conclusions: These pilot data suggest that HS diets may increase IP in men, and, in the context of a HS/LK diet, greater IP is associated with lower FMD and higher BP in all participants. NIH R01 HL145055. 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.
Unexplained infant death in Houston, TX: A 17-year retrospective
Authors: Lusk Savannah , Blessing Melissa , Chang Andersen , Bachim Angela , Greeley Christopher , Ross Jennifer , Ray Russell 
Published: May 2024

SIDS/SUID (henceforth referred to as SIDS) is a leading cause of neonate death, taking the lives of ~10 infants every day in the US alone. SIDS is defined as the death of an infant for which no cause of death can be determined after a complete autopsy, death scene investigation, and medical history review, all of which makes SIDS a very diffcult disease to study. Death scene investigations have identified several contributing environmental factors. However, etiological investigation has been complicated by inconsistencies in classification of death by medical examiners or coroners and unreliable resources for law enforcement to complete death scene investigations, which leads to epidemiological studies often lacking rigor or suffcient data. Using data from Child Fatality Review Team (CFRT) of Harris County, the Medical Examiner’s Offce, and the Texas Department of State Health Services, we performed a retrospective analysis of 17-years of SIDS cases in Harris County, Texas. We applied a novel birth rate correction for SIDS rates over the first year of life. Associations were tested using a Tukey HSD and linear regression models with co-linear factors considered. To focus on biologically unexplained SIDS cases, we subsetted our dataset to only include SIDS and Undetermined causes of death. Our preliminary data includes 1,094 cases comprised of ~43% black, ~32% Hispanic, ~20% white, ~3% Asian, and ~0.4% unknown and 57% male infants. Distribution of death across the first 12 months of life shows a peak of death around 2 months of age. We do not see an association with month or season in the raw SIDS data nor when using our novel correction for birth rates. When we apply the standard per 1,000 live births normalization, we see a significant increase in Spring and Winter. We also report race-dependent significant differences in yearly and monthly case numbers, male-to-female ratios, and age at death and additional significant race-dependent associations between SIDS cases and adults diagnosed with asthma, income level, and overcrowding based on Zip Code. This dataset represents one of the most racially and socio-economically diverse in the United States. Our data suggests that standard trends may be driven by majority white datasets and that response to socioeconomic stress varies by race/ ethnicity, which leads to differences in risk between classically described minority groups. NIH: 1F32HL160073-01A1, R01HL130249 44617-S4. BCM McNair Scholar Program, March of Dimes Basil O'Connor Research Award, Parker B. Francis Fellowship, CJ Foundation for SIDS. 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.
Alcohol-associated skeletal muscle mitochondrial dysfunction: insights into Sirt1 regulation
Authors: Rodríguez-Graciani Keishla , Molina Patricia , Simon Liz 
Published: May 2024

Alcohol-induced skeletal muscle dysfunction affects approximately 50% of individuals with alcohol use disorder (AUD). Alcohol dysregulates mitochondrial oxidative metabolism and promotes oxidative stress. However, the impact of alcohol on skeletal muscle bioenergetic capacity and cellular redox balance remain to be fully elucidated. The expression and activity of Sirtuin 1 (SIRT1), an NAD+-dependent deacetylase, is dysregulated with ethanol metabolism. This disruption has the potential to play a significant role in the intricate regulatory network responsible for alcohol-induced mitochondrial dysfunction in skeletal muscle. Interventional strategies, such as exercise, have the potential to enhance mitochondrial function and promote overall skeletal muscle health. We hypothesize that alcohol dysregulates myotube mitochondrial bioenergetics by reducing mitochondrial respiration in a Sirt1-dependent manner, and we predict that simulating exercise through electrical pulse stimulation will increase Sirt1 expression. Myoblasts were differentiated into myotubes in the presence of ethanol (0 and 50 mM) for 3 days prior to Mito Stress Test using the Seahorse XF Pro Analyzer. Differentiated myotubes treated with ethanol (0 and 50 mM, for 3 days), were exposed to electrical pulse stimulation simulating exercise (30V, 1Hz, 2ms pulses) for 24 h. A mixed-effects model with Šidák correction and repeated samples t-test was used. Means with p-value of less than 0.05 were considered statistically significant. Preliminary analysis indicates significant decrease in ATP-linked mitochondrial respiration (p<0.05) in the presence of ethanol. Ethanol also decreased myotube Sirt1 activity (p<0.05) and Sirt3 protein expression. There was a main effect of electrical pulse stimulation to increase Sirt1 activity (p<0.001) in both the control and ethanol-treated groups. Ongoing analysis will identify alcohol-mediated changes in proteins involved in mitochondrial dynamics regulated by Sirt1. These results show that ethanol significantly decreases mitochondrial bioenergetics in differentiated human myotubes. The ethanol induced changes in Sirt1 activity and Sirt3 protein expression, suggest a potential role of Sirt1-mediated mitochondrial dysregulation with alcohol. This research was supported by NIH/NIAAA T32AA007577, P60AA009803 (PEM) and R21AA030869 (LS). 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.
GCLM Expression Drives Macrophage Efferocytosis
Authors: Delgadillo Luisa , Rashdan Nabil , Mackay Ryan , Yurdagul Arif , Pattillo Christopher 
Published: May 2024

Atherosclerosis, a chronic inflammatory disease characterized by the accumulation of lipids, apoptotic cells (ACs), and fibrous elements within the arterial wall, can lead to plaque rupture, one of the most common causes of death in cardiovascular disease (CVD). Rupture prone plaques, characterized by large necrotic cores and thin fibrous caps, lead to acute luminal thrombosis resulting in myocardial infarctions (MI) and strokes. AC accumulation coupled with deficiency in their clearance, results in necrotic core formation. Macrophages are responsible for clearing ACs through efferocytosis; however, as atherosclerosis progresses efferocytosis is impaired. AC accumulation leads to chronic inflammation driven by reactive oxygen species production that disrupts cellular redox balance. Glutathione (GSH), the main antioxidant in the body, maintains redox balance; however, it fails to do so in atherosclerosis. Reports have shown a single nucleotide polymorphism (SNP) in the promoter region of the modifier subunit of GCL (GCLM), a rate limiting enzyme responsible for de novo synthesis of GSH, limits its transcription under oxidative stress and is associated with increased risk of MI. Moreover, deletion of GCLM shows an increase in atherosclerotic plaque area and necrotic core, however it remains unknown how GCLM contributes to necrotic core formation and increased CVD incidence. Methods: Bone marrow derived macrophages from WT, Het, and KO GCLM mutant mice and peripheral blood mononuclear cells (PBMCs) from blood donors were isolated and used for efferocytosis and protein assays. PBMCs and atherosclerosis plaque sections were used for SNP genotyping and in situ efferocytosis assays. Results: Efferocytosis impairment correlated with decreased GCLM expression in mice. The presence of a SNP in GCLM significantly decreases efferocytosis in vitro as well as in situ in stage 5 human plaques. Conclusion: These results suggest that loss of GCLM in macrophages impairs primary and secondary efferocytosis in mice. This is corroborated with the inhibition of GSH synthesis. We also observed an impairment in efferocytosis in human macrophages with the presence of the risk allele in GCLM. Malcolm Feist Pre-doctoral Fellowship, Center of Cardiovascular Diseases and Sciences. 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.
Spatiotemporal mapping of renal innervation and impact of in utero fetal denervation on kidney development
Authors: N'Guetta Pierre-Emmanuel , McLarnon Sarah , O'Brien Lori L 
Published: May 2024

Proper kidney function is intricately linked to cardiovascular health. To help maintain homeostasis, the kidney is innervated by peripheral nerves which play significant roles in the regulation of renal function. Our lab has recently established that peripheral neurons composed of both sympathetic and sensory fibers innervate the kidney concomitantly during arterial differentiation, following guidance cues released by renal stromal cells. Yet, it remains unknown whether renal nerves actively direct organogenesis as they establish neuroeffector junctions to begin mediating physiology. In this study, we hypothesize that renal nerves release spatially and temporally important signaling factors which regulate kidney development. To test this hypothesis, we genetically ablated renal nerves in utero utilizing a whole animal Ntrk1 knockout (TrkA) which is required for neuronal survival. Using 3D light-sheet imaging and IMARIS analysis on wild-type ( TrkA+/+) (n=6), heterozygous ( TrkA+/-) (n=6), and mutant ( TrkA−/−) (n=6) mice, we assessed morphology and number of renal structures in at P0. We found total glomeruli number was decreased (P1-way Anova <0.001) and glomeruli diameter was increased (P1-way Anova <0.001) in heterozygous TrkA+/- and further in mutant TrkA−/− denervated kidneys compared to TrkA+/+ wild-type kidneys at P0. Using immunofluorescence (IF) on kidney section, we observed that proximal tubule diameter was increased (PT-test < 0.0001) in mutant TrkA−/− denervated kidneys compared to TrkA+/+ wild-type kidneys at P0. These data suggest that renal nerves are poised to impact nephron morphology and/or function during kidney development. We further established that renal nerves traffcked Synapsin 1+ vesicles showing that they establish neuro-effector junctions with developing kidney structures like glomeruli and tubules suggesting potential cellular crosstalk important for development. Future efforts will aim to conditionally delete sensory or sympathetic renal nerves independently and investigate the developmental and resulting functional phenotypes. Taken together our findings will significantly bridge the gap in knowledge concerning the establishment of renal innervation and the role of nerves in kidney development and disease. O'Brien Lab Startup Fund, R01DK121014 (O'Brien, PI). 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.