bluuebunny/crossref_metadata_2025 huggingface dataset:
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.
Butyrylcholinesterase Is Not Required for the Neonatal Autoresuscitation Reflex
Authors: Memos Nicoletta , Lanza Denise , Heaney Jason , Ray Russell
Published: May 2024

Sudden Infant Death Syndrome (SIDS) is the leading cause of infant death under the age of one year of age, taking the lives of more than 1,400 infants annually, and comprising approximately 41% of all Sudden Unexpected Infant Death (SUID) cases. SIDS etiology remains vastly unknown but is best explained via a triple risk model that proposes SIDS occurs in a vulnerable infant during a critical developmental period when triggered by an external stressor. In SIDS it is hypothesized that there is first a failure in arousal followed by failure in the protective autoresuscitation reflex; a defense mechanism for an infant that is in a hypoxic coma, that promotes deep gasping to attempt to restart cardiovascular function. Many SIDS case studies reveal associations with genetic variants and abnormal biomarkers; however, it is unclear whether these variants are causal. Recently a case study identified a broad association between reduced blood BChE activity and SIDS cases, yet the functional relationship between BChE and respiratory regulation remains to be investigated. We aimed to functionally test the relationship between BChE and the neonatal autoresuscitation reflex utilizing a rapid pipeline for precision genetic modeling and high-throughput functional testing developed by the Ray Lab. BChE loss of function mice, generated through targeted genetic editing, were tested for neonatal autoresuscitation on our automated closed loop phenotyping platform, Looper. Postnatal day 7-8 mice were exposed to 3% CO2 and 97% N2 stimuli to induce a state of hypoxia resulting in detection of bradycardia, initial hyperventilation, hypoventilation, and apnea followed by restoration of room air conditions to facilitate the autoresuscitation reflex and cardio-respiratory recovery. Male and female mice were exposed to repeated anoxic gas challenges and allowed to autoresuscitate until death occurred. Data suggest that loss of BChE function does not affect neonatal autoresuscitation. BChE knockout mice and heterozygous mice survived similar amounts of anoxic challenges as wild type controls. No sex differences were observed between the number of anoxic challenges survived in males and females for all genotypes. Our data demonstrate the first functional assessment of BChE in neonatal cardio-respiratory regulation and the autoresuscitation response and highlight that BChE is not required for successful neonatal autoresuscitation. Additional analyses of respiratory parameters from respiratory trace data for BChE loss of function mice will aid in a further understanding if BChE loss of function is implicated in other aspects respiratory regulation.

Funding: Precision Core funding U54 OD030165. NIH/NHLBI R01HLN161142-01 and R01HL130249-07.

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.
Knockout of LRRC8A Anion Channels in Vascular Smooth Muscle Cells Impairs NF-κB and Hif1α-mediated Signaling
Authors: Panja Sourav , Choi Hyehun , Nguyen Hong-Ngan , Lamb Fred S.
Published: May 2024

Vascular smooth muscle cell (VSMC) inflammation associated with the development of vascular disease, including hypertension. We have demonstrated that knockout (KO) or inhibition of LRRC8A anion channels in VSMCs attenuates reactive oxygen species (ROS) production by NADPH oxidase 1, impairs TNFα-induced inflammation, and promotes vascular relaxation in murine mesenteric arteries. To explore the mechanism of these effects we performed RNA sequencing (RNAseq) on LRRC8A wild-type (WT) and knockout (KO) VSMCs (N = 3 pairs) under control conditions and 6hrs following TNFα treatment (10ng/ml). The data were normalized by Median ratio (DESeq2) and differential expression was determined by DESeq2 method using Partek software and pathway enrichment analysis was done by KEGG pathway. Differential expression of genes of interest was confirmed by quantitative PCR (qPCR) in both cultured cells and in whole aortic tissues (endothelium-denuded, N = 3) from LRRC8A WT and KO mice. HIF1α transcriptional activity was quantified by luciferase reporter assays in cells exposed to hypoxia (1% oxygen) or cobalt chloride (300μM) for 6 hrs. RNAseq demonstrated broad impairment of pro-inflammatory signaling in KO cells. This was consistent with previous observations of impaired nuclear factor kappa B (NF-κB) reporter activation by TNFα in the absence of LRRC8A. Compared to WT VSMCs, resting LRRC8A KO VSMCs exhibited statistically significant downregulation of 33 NF-κB target genes including the IL-6 (Il6) and IL-1β (Il1r1) receptors. TNFα treatment increased the expression of 37 NF-κB target genes in WT cells. Most of these genes (34 genes) were not significantly activated by TNFα in KO cells, while 3 genes (chemokine (C-C motif) ligand 20; CCL20, prostaglandin E synthase; PTGES and vascular endothelial growth factor C; VEGFC) were significantly downregulated. Pathway analysis data revealed that Hif1α signaling appear in the top downregulated pathway and it was impaired as 14 Hif1α target genes were downregulated in unstimulated KO VSMCs. In addition, expression of Rps4i, a long non-coding mRNA associated with inhibition of HIF1α signaling was significantly upregulated. Luciferase reporter assays following exposure to hypoxia or cobalt chloride confirmed impaired Hif1α activation in LRRC8A KO cells. Important target genes for HIF1α, including HK2, LDHB, ACE, BMP4 and PFKP, were less activated, while RPS4i remained upregulated compared to WT cells. These findings demonstrate disruption of both NF-κB and HIF1α signaling in VSMCs lacking LRRC8A. This anion channel represents a novel target for anti-inflammatory therapy in vascular disease.

This work was supported by DK132948 and HL160975.

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.
Exogenous T4 Increased Cardiac Thioredoxin Protein Expression in Insulin Resistant OLETF Rats
Authors: Hernandez Garcia Jenifer , Mendez Dora A. , Ortiz Rudy M.
Published: May 2024

Thioredoxin (Trx) is a protein that regulates cellular signaling and antioxidant defense. Cellular antioxidant mechanisms are designed to protect cells from oxidative damage caused by inappropriately elevated reactive oxygen species (ROS) and other free radicals. Oxidative damage can lead to cellular damage and impaired function. Diabetic cardiomyopathy (CDM) is associated with impaired redox balance and oxidative injury. Altered fuel metabolism is a key feature of CDM characterized by an imbalance in fatty acid and glucose utilization, favoring fatty acid overutilization. Excessive fatty acid beta-oxidation in the mitochondria leads to generation of free radicals including superoxide, which can contribute to oxidative injury. Thyroid hormones regulate substrate utilization and their dysregulation may contribute to oxidative injury. Therefore, we hypothesized that exogenous thyroxine (exoT4) upregulates Trx protein expression and ameliorate oxidative injury in the hearts of insulin resistant rats. Insulin resistant, Otsuka Long Evans Tokushima Fatty (OLETF) rats were used to assess the effects of exoT4 on heart Trx, oxidative damage, and glucose metabolism. Rats were assigned to four groups: (1) lean, control Long Evans Tokushima Otsuka (LETO; n=6), (2) LETO + T4 (8 μg/100g BM/d × 5 wks; n=7), (3) untreated, insulin resistant OLETF (n=6), and (4) OLETF + T4 (n=7). OLETF group displayed a 31% decreased in TRX compared to Leto. T4 increased Trx protein expression by 88% in OLTEF compared to untreated OLETF. This data suggests that exoT4 has the potential to upregulate cardiac Trx-dependent antioxidant mechanisms in insulin resistant OLETF rats to ameliorate oxidative injury and improve cardiac glucose metabolism.

This work is supported by the American Heart Association and the Undergraduate Research Opportunity Center (UROC).

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.
WNK-SPAK-NKCC1-KCC2 pathway in SCN: a novel regulator of neuronal activity
Authors: Romero Estrada Vanessa , Bonilla García Gianelli , Moreno Martínez Reyna , Gamba Ayala Gerardo , Chávez Canales María
Published: May 2024

Background: The suprachiasmatic nucleus (SCN) plays a vital role in regulating an organism's physiological and behavioral processes by synchronizing them with the light-dark cycle. The SCN receives GABAergic inputs that may be excitatory or inhibitory, depending on the intracellular chloride concentration ([Cl−]i) that is regulated by NKCC1 and KCC2 cotransporters, determined by the WNK-SPAK/OSR1 phosphorylation pathway. Our study aimed to investigate the role of the WNK-SPAK-NKCC1-KCC pathway in regulating SCN neuronal activity.Methods: First, we perform an in silico analysis to determine the expression of the genes involved in this pathway. Furthermore, the expression of the proteins was confirmed by an immunofluorescence assay. Next, to determine if the WNK-SPAK-NKCC1-KCC2 pathway affects neuronal activity in the SCN we performed the immunohistochemical analysis of c-Fos expression in the SCN at ZT2 and ZT14 in the SPAK-KI mice. Finally, to find out if the change in SCN neuronal activity between day and night is related to pathway activity, we performed an immunofluorescence study. Results: We observed that various genes governing the pathway's regulation exhibit oscillations not only in neurons but also in other cell types. Remarkably, SPAK-KI mice displayed a significant surge in neuronal activity at ZT2 when contrasted with the control group. Additionally, we detected increased phosphorylation levels of WNK, SPAK, NKCC1, and KCC2 isoforms at ZT14 as compared to ZT2.Conclusions: Our study highlights the role of SPAK kinase in regulating SCN neuronal activity and suggests that the pathway is active during the dark period, leading to an increase in [Cl−]i during the day, as previously reported.

The authors are supported by grants from CONACyT Mexico no. 87794, and from PAPIIT UNAM no IA208522 and IN223324.

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.
A Novel Approach for Assessing Mitochondrial Respiration in Freshly Isolated Glomerular and Tubular Fractions from Whole Mouse Kidney
Authors: Decker Stephen , Paula Venisia , Al-Rabadi Laith , Funai Katsuhiko
Published: May 2024

Intro: Understanding mitochondrial function within specific renal compartments is crucial for unraveling the intricate metabolic processes underlying kidney physiology and pathophysiology. In this study, we present a novel method for accurately measuring mitochondrial respiration in freshly isolated glomerular and tubular fractions derived from dissected kidneys. Methods: Employing a differential adhesive sieving technique, we isolated glomerular and tubular fractions from freshly harvested whole kidneys (n=2) and subsequently utilized a standard substrate-inhibitor titration protocol to assess mitochondrial respiration in the Oroboros Oxygraph O2K (Oroboros Instruments, Innsbruck AT). Results: Notably, our findings revealed distinct state 3 respiration rates in various fractions, with the 70 μm tubule fraction exhibiting a rate of 2133.029 pmol/sec/mgprotein, the 40 μm tubule fraction displaying a rate of 522.4116 pmol/sec/mgprotein, the first glomerular fraction demonstrating a rate of 407.7911 pmol/sec/mgprotein, and the second tubular fraction manifesting a rate of 362.3286 pmol/sec/mgprotein. Moreover, these fragments exhibited differential substrate preferences, as the addition of succinate increased state 3 respiration by ~90% in the 70 μm tubule fraction. In contrast, succinate increased respiration by ~30% in the 40 μm tubule and glomerular fractions. Discussion: These ongoing experiments provide compelling evidence supporting the feasibility and reliability of our approach in quantifying mitochondrial respiration within isolated renal fractions. Our methodology not only enables precise measurements of mitochondrial function in distinct nephron segments but also lays the groundwork for further investigations into the physiological and pathological implications of mitochondrial dynamics in kidney health and disease.

This research is supported by the National Institutes of Health under Ruth L. Kirschstein National Research Service Award 5T32DK091317 from the National Institute of Diabetes and Digestive and Kidney Diseases and the National Kidney Foundation of Utah and Idaho.

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.
Role of endothelial cell-selective adhesion molecule in the regulation of pulmonary vascular resistance
Authors: Buncha Vadym , Lang Liwei , Whitebloom Grant , Fopiano Katie Anne , Bagi Zsolt
Published: May 2024

Endothelial cell-selective adhesion molecule (ESAM) is a member of the endothelial cell junction adhesion molecules family, which plays an important role in the maintenance of endothelial barrier function in the pulmonary circulation. The role of ESAM in affecting pulmonary vascular resistance remains unknown. To examine the role of ESAM in pulmonary vascular resistance, whole lungs were isolated from 16-18 weeks old ESAM knock out (KO) mice and wild type (WT) littermates, ventilated and perfused. We found that pulmonary vascular resistance is significantly increased in the lung of ESAM KO mice compared to WT mice. Bradykinin-induced, endothelium-dependent reduction in the pulmonary vascular resistance was impaired in ESAM KO mice, whereas the direct NO donor, sodium nitroprusside-induced endothelium independent responses remained similar in WT and ESAM KO mice. U46619 mediated increases in pulmonary vascular resistance was significantly higher in ESAM KO mice. Inhibition of the NO synthesis with the L-NAME (0.2 mM for 10 minutes) augmented the U46619-mediated increase in pulmonary vascular resistance in WT mice, but it did not affect the U46619 response in the ESAM KO mice. The mRNA expression of pro-inflammatory cytokines, including interleukin-6 and tumor necrosis factor, was increased in the lungs of ESAM KO mice, whereas expression of collagen isoforms (type I and type III) and fibronectin were similar in WT and ESAM KO mice. Collectively, we propose that ESAM plays an important role in the maintenance of pulmonary vascular resistance, likely via preserving endothelial nitric oxide production in pulmonary arteries.

AHA predoctoral award ID 917057.

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.
Altered alveolar cell signature in pre- and post-natal Trisomy 21 lung
Authors: Pelayo Natalya , Belgacemi Randa , Frauenpreis Andrew , Youssef Eman , Cherry Caroline , Bhattacharya Soumyaroop , Mariani Thomas
Published: May 2024

Rationale: Pulmonary and cardiovascular disorders result in 75% of the mortality observed in individuals with Down Syndrome (DS). However, little is known about the pulmonary anomalies observed in DS, as they are often considered a secondary condition to congenital heart defects. However, we and others have demonstrated that lungs from patients with trisomy 21 (T21) may present alveolar abnormalities, such as pulmonary alveolar hypoplasia, regardless of congenital heart disease. Therefore, the etiology of alveolar defects in T21 lungs remains elusive. The aim of our study is to define the molecular and cellular defects underlying alveolar defects in T21 developing lungs. Methods: Single cell RNA sequencing data was generated from 5 T21 and 4 non-T21 human fetal lungs (18 weeks gestation). T21 and non-T21 human fetal lung tissues (aged 18 to 22 weeks gestation), and postnatal human lung tissues from 2 months to 6 years old were processed to compare and determine the localization and expression of alveolar cells and their markers by RT-qPCR, fluorescence in situ hybridization (FISH) and immunofluorescent staining (IF). Results: Our single cell data showed an increase in the proportion of mature fetal AT2 cells in T21 as compared to non-T21 samples, whereas a decrease was observed in the intermediate and progenitor cell populations. When comparing fetal T21 to non-T21 samples, RT-qPCR results demonstrated significantly increased expression of both alveolar type II markers (SFTPD, ABCA3, SCGB3A2, LAMP3) and the alveolar type I marker AGER. Furthermore, FISH showed a significant increase in SFTPC and SFTPB in fetal T21 lungs. Conversely, when comparing postnatal T21 to non-T21 samples, RT-qPCR results demonstrated reduced expression of alveolar type II markers (SFTPB, SFTPD, ABCA3, SCGB3A2, LAMP3) and alveolar type I markers (HOPX, AGER, PODOPLANIN). Our IF staining in postnatal T21 vs non-T21 showed a significant increase in the number KRT8 and KRT8+/SFTPC+ cells, markers of an intermediate progenitor cell population, accompanied by a decrease in proliferating AT2 cells (SFTPC+/Ki67+). Conclusion: While our single cell data, RT-qPCR, FISH and IF results show an accelerated maturation during T21 lung fetal pre-alveolar development, postnatal T21 lungs display a decrease in mature AT2 cell numbers. This could likely be due to an accelerated maturation early on in development, that suppresses proper proliferation necessary to expand the pool of AT2 cells to a normal range. This suppression seems to persist into the postnatal period.

3R21HL165411-02S1. NIH/NHLBI Offce of The Director, National Institutes of Health (OD) R01HL155104 (SD).

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.
Exploring Contextual Factors in Vagal Tank Theory
Authors: De Leon Sautu Samantha , Gonzalez Marlen
Published: May 2024

High baseline Heart rate variability (HRV) is a putative measure of resilience which predicts adaptive HRV changes during (Reactivity) and after (Recovery) a stressor according to Vagal Tank Theory. However, we do not understand how the availability of resources prior to a stressor impacts this relationship. Using an ecological framework, we tested VTT hypotheses while examining receptivity to social presence and contemplative practices as a moderator to Reactivity and Recovery during a subsequent stressor. Using ECG, we modeled HRV as the root-mean square of successive R-R intervals (RMSSD) across four conditions: baseline, post contemplative practice, directly before a CO2 breathing tasking, while breathing CO2, and after CO2. Reactivity and Recovery were defined as the usual subtraction for phasic HRV literature, while Receptivity was modeled as post contemplative practice HRV minus baseline. Our multiple regression analyses showed that higher baseline predicted greater reactivity, positively interacting with the female gender and the partner condition (F(9,83)=2.00, p=0.04). Higher baseline predicted lower recovery HRV with no significant interactions (F(9,85)=2.66, R2=0.22, p=0.009), potentially due to the benefit in the HRV level at the reference level (after contemplative practice). Higher receptivity predicted higher recovery, with women showing the strongest relationship (F(4,88)=16.3, R2=0.43, p<0.001). Our results suggest that both baseline and receptivity to resources may impact resilience to stress, and that future research should account for gendered effects.

Cornell 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.
Calcium-dependent dual oxidase 2 is a novel source of reactive oxygen species implicated in glomerular mesangial cell fibrotic response to angiotensin II and glucose
Authors: McLachlan Mark , Hecker Jacqueline , Ford Bridget
Published: May 2024

The vasoactive peptide angiotensin II (Ang II) and hyperglycemia contribute to the initiation and the progression of glomerular fibrosis via activation of glomerular mesangial cells (MCs) and subsequent extracellular matrix expansion. We have previously shown that oxidative stress is critical for MC fibrotic response to Ang II or high concentrations of glucose (HG). Here, we demonstrate that Dual oxidase 2 (Duox2), a member of the Nox/Duox family of NADPH oxidases, is present in MCs and that its protein expression, along with its associated maturation factor, DuoxA2, are upregulated by Ang II and HG. Small interfering RNA (siRNA)-mediated downregulation of Duox2 significantly reduces Ang II-induced increase in reactive oxygen (ROS) generation and prevents the stimulatory effect of Ang II on MC fibrotic injury (as assessed by measuring a-smooth muscle actin and fibronectin expression). To demonstrate that Duox2 activation is Ca2+-dependent, we show that the extracellular Ca2+ chelator BAPTA prevented Ang II-induced ROS generation and the stimulation of MC fibrotic injury by Ang II. Moreover, treatment of MCs with ionomycin resulted in increased ROS production and enhanced MC fibrotic injury. These effects were abrogated by siRNA targeting Duox2. Fura-2 fluorescence was utilized as well to show calcium mobilization in response to Ang II and this effect was abrogated with siDuox2 transfection. These data indicate that Ang II-stimulated Duox2 activation and ROS generation subsequently lead to MC fibrotic injury. In summary, we have identified a novel role for Duox2 and its cognate maturation factor, DuoxA2, as a major source of ROS in response to Ang II and HG and established the significance of Duox2 in Ang II-mediated MC activation and fibrotic injury. Therapeutic targeting of this pathway may prevent or reverse pathophysiologic manifestations of renal fibrotic diseases.

Research reported in this poster was supported by the University of the Incarnate Word Offce of Research and Graduate Studies and the National Institute of General Medical Sciences of the National Institutes of Health under Award Number SC2GM136569. The content is solely the responsibility of the authors and does not necessarily represent the offcial views of the National Institutes of Health.

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.
Act88F pseudo-acetylation of lysine 50 (K50) negatively regulates muscle function in Drosophila
Authors: Godoy Luis , Lopez Adrian , Stewart Travis , Madan Aditi , Baker Josh , Cammarato Anthony , Ferguson Bradley
Published: May 2024

Non-histone post-translational modifications (PTMs) are an increasingly important area of study that contribute to our understanding for protein function in the control of health and disease. Protein PTMs, such as acetylation, are emerging as key regulators of striated muscle function, yet our understanding of how non-histone protein acetylation affects muscle physiology remains fragmentary. Previous reports from our lab identified lysine (K) 52 of skeletal muscle alpha actin (ACTA1) to be acetylated, yet no reports have shown a role for ACTA1 acetylation in muscle function. Act88F is 93% homologous to ACTA1 and K50 is identical to K52 of ACTA1. Thus, for these studies, we mutated K50 with a glutamine (Q) on the Act88F gene in the indirect flight muscle (IFM) of Drosophila to mimic acetylation. We examined physiological function (i.e. flight and climbing) as well as biophysical changes between acetylated Act88F and the associated myofibrillar proteins involved in contraction and relaxation (myosin, tropomyosin, and troponin). We report that Act88F K50Q pseudo-acetylation resulted in a flightless phenotype and decreased climbing ability. In addition, we report that Act88F K50Q flies had increased IFM damage as examined via fluorescent imaging. Interestingly, Act88F K50Q did not change actin-myosin binding, actin sliding velocity, or Ca2+ sensitivity in actin-motility assays. However, Act88F pseudo-acetylation did decrease actin filament length, but only after interacting with myosin, implying that Act88F acetylation increases actin filament breaking. These data suggest that Act88F acetylation at K50 worsens muscle function by destabilizing filamentous actin, resulting in muscle tearing and damage to the IFM, which results in loss of flight. This work suggests that actin acetylation, at least on lysine 50, in response to environmental stressors or diet could greatly change muscle function and sarcomere integrity.

This research was funded by the Dennis Meiss & Janet Ralston Fund for Nutri-epigenetic Research, the National Institute for General Medical Sciences (NIGMS) of the NIH (P20 GM130459), the National Heart, Lung, and Blood Institute of the NIH (R15 HL143496), National Institute of Aging of the NIH (R21 AG077248) and NSF EPSCOR Track II (OIA-1826801) to B.S.F.

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.
Exogenous Thyroxine Normalizes Decreased Heart Rate in Insulin Resistant OLETF Rats
Authors: Mendez Dora A. , Pacher Pal , Ortiz Rudy M.
Published: May 2024

Diabetic cardiomyopathy (DCM) is defined as heart failure in the absence of overt clinical coronary artery disease, valvular disease, hypertension, and dyslipidemia in diabetic patients. Patients with T2DM display left ventricular dysfunction, fibrosis, and abnormal cell signaling leading to diastolic and systolic dysfunction. Increased left ventricular mass and fibrosis potentially leads to abnormal diastolic function. Substantial data exists demonstrating both insulin-dependent and non-insulin dependent diabetes impairs left ventricular function. During insulin resistance, a metabolic shift occurs favoring fatty acid metabolism at the expense of impaired glucose metabolism, leading to lipotoxicity, increased oxidative stress, and inflammation. Thyroid hormones have shown to be cardioprotective. We have previously shown exogenous thyroxine treatment increased GLUT4 translocation and nuclear factor erythroid 2-related factor 2 (Nrf2) in cardiac tissue, demonstrating the potential to improve glucose metabolism and increase antioxidant defense mechanisms. Insulin resistant, Otsuka Long Evans Tokushima Fatty (OLETF) rats were used to assess the effects of exogenous thyroxine (T4) on left ventricular cardiac function and hemodynamics to assess if the previously observed improvements in cellular metabolism translated to functional improvements. Rats were assigned to three groups: (1) lean, Long Evans Tokushima Otsuka (LETO; n=7), (2) untreated OLETF (n=6), and (3) OLETF + T4 (8 μg/100g BM/d × 6 wks, n=7). Left ventricular function was measured by the pressure-volume system. Heart mass increased in untreated OLETF (1.46 ± 0.08) and treated OLETF (1.61 ± 0.16) compared to LETO (1.19 ± 0.08). Cardiac output (CO) and stroke volume were 26% and 56% greater in untreated OLETF compared to LETO. Heart rate (HR) was 27% lesser in untreated OLETF compared to LETO. While exogenous T4 did not alter CO and SV compared to untreated OLETF, it did normalize HR to LETO levels. The differences in CO between LETO and OLETF suggest that elevated T4 alters the mechanisms (SV vs HR) by which CO is elevated during MetS. The changes may be compensatory to accommodate the cardiac hypertrophy observed in the strain.

American Heart Association Award # 946746 APS Porter Physiology Development Fellow (2nd year).

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.
Sex Differences in Obesity- and Aging-Mediated Increase of Body Weight and Blood Pressure
Authors: Di Sole Francesca , Babich Victor , Li Jung , Barnes Maria J
Published: May 2024

The rate of obesity is steadily increasing world-wide, and obesity may predispose to chronic kidney disease (CKD) via direct pathway or through its complications such as hypertension. Furthermore, incidence of CKD is affected by aging and obesity accelerates aging especially in association with its complications. Specifically, the relationship between obesity and aging in controlling CKD progression has not been well-defined. To address this gap in knowledge, we generated a diet-induced obesity mouse model of 52-58-week-old animals and started the characterization of the model by measuring body weight and blood pressure in male and female mice. We studied four groups of mice: first and second groups were male mice, fed 60% high-fat (HF) diet or 10% low-fat (LH) diet for 19 weeks. Third and fourth groups were female mice, fed HF or LF diet for the same number of weeks. A gain in body weight was measured in male mice on HF when compared to male mice on LF diet and was associated with a significant diet-dependent increase (about 30%) in blood pressure. The body weight gain in female mice was more pronounced than in male mice (62% female vs. 54% male). The blood pressure was higher in female mice than in age-matched male mice in control conditions and was not affected by the diet. These findings suggest sex differences in the increase of body weight and blood pressure mediated by diet-induced obesity in mice of 52-58 weeks of age. In summary, our mouse model mimics the phenotype seen in humans and its characterization is valuable to aid the understanding of the relationship of determinants that control the progression of kidney diseases.

Des Moines University IOER Research & Grant Award.

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.
Compatibility of eugenol anesthesia with classroom physiology experiments on nerve and muscle of frogs
Authors: Rees Katherine , Foucrier Skye , Sekhon Ryan , Blank Jason
Published: May 2024

Frogs serve as valuable model organisms for studying physiological responses of nerve, skeletal muscle and the heart in undergraduate biology labs. Heretofore, induced hypothermia has been the preferred technique for pain and stress reduction prior to euthanasia by pithing. However, AVMA guidelines discourage hypothermia for restraint or euthanasia of amphibians and advocate anesthetic overdose as preferable to pithing alone. Unfortunately, the primary anesthetic used in fish and other aquatic invertebrates, MS-222, blocks normal nerve and muscle function in leopard frogs and renders them useless for classroom physiology experiments, as demonstrated by Medler (2019). Eugenol is a safe and affordable anesthetic that is effective in amphibians. We sought to test the hypothesis that eugenol anesthesia is compatible with classroom nerve and muscle experiments on frogs. Bullfrogs and leopard frogs were immersed in a bath of eugenol suspended in tap water at 275 to 350 mg/L. At various time points, a four step reflex test was performed including tests of righting response, superficial pain reflex, deep pain reflex, and corneal blink reflex. Once all reflexes were absent, the frog was euthanized by pithing and the gastrocnemius muscle was prepared for force recordings. The sciatic nerve was stimulated with a bipolar stimulating electrode while gastrocnemius force was measured using an isometric force transducer. The threshold voltage eliciting a muscle contraction and the peak isometric twitch force were recorded at 15 minute intervals for 2 hours. Control frogs were sedated by immersion in ice water for 20 to 30 minutes, pithed when reflexes were substantially weakened, and then subjected to the same stimulation protocol and force measurements. At these doses, eugenol reliably induces loss of reflexes in 20 to 35 minutes and neuromuscular preparations maintain the ability to respond to electrical stimulation. Preliminary results suggest that eugenol may produce a modest elevation of threshold voltage and a modest reduction in maximum twitch force compared to control frogs euthanized without chemical anesthesia. Eugenol may be an effective anesthetic to prepare bullfrogs and leopard frogs for classroom experiments on nerve and muscle.

Funding was provided by the Bill and Linda Frost Fund.

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.