bluuebunny/crossref_metadata_2025 huggingface dataset:
Liver Wound Healing Is Associated with An Increase in Mfge8 Expression in Hepatocytes
Authors: Bu Heng-Fu , Geng Hua , Subramanian Saravanan , Chou Pauline , Tan Xiao-Di , Tan Xiao-Di
Published: May 2023

Being recognized as a typical pathological feature of liver diseases, apoptosis-induced hepatocyte injury leading to sterile inflammation drives a wound-healing path in vivo. We and other researchers reported that Milk fat globule-EGF factor 8 (MFGE8) preserves tissue homeostasis, protects against tissue injury and inflammation, and attenuates nonalcoholic fatty liver disease and fibrosis. However, it is unclear whether and how MFGE8 is involved in liver regeneration from hepatocyte-apoptosis-induced injury. Our aim is to study current knowledge to this extent, we created a novel triple-transgenic mouse model, an inducible hepatocyte-specific apoptosis phenotype (namely, 3XTg-iHAP), in which the inducible hepatocyte-specific FasL expression is under control of the combined LoxP-Albumin-Cre system and rtTA Tet-On regulatory element. The liver tissues from 3XTg-iHAP and their littermates were collected at 8 h, 24 h, 48 h, 72 h, and 5 D after doxycycline (Dox, 5mg/kg, s.c., single dose) treatment and subjected to histological examination, RNAScope in situ hybridization (ISH) and qRT-PCR analysis. We first confirmed that the 3XTg-iHAP mice developed normal, viable, and fertile. Upon Dox treatment, qRT-PCR confirmed FasL expression was specifically induced in the liver tissues of 3XTg-iHAP mice (male, 7 weeks) but not in their littermates. H&E sections show the induction of hepatocyte apoptosis as early as 24 h followed by apoptosis-induced sterile inflammation and injury, hepatocyte mitosis, and regeneration in the liver parenchyma of 3XTg-iHAP mice. In the ISH assay, we found that (1) In littermate control mice, Mfge8 transcripts were localized in the intrahepatic bile duct epithelial cells (i.e., cholangiocytes) within the portal area. (2) In Dox-treated 3XTg-iHAP mice, we observed a profound increase of Mfge8 gene expression in parenchymal hepatocytes of the liver featured with apoptosis-associated sterile injury. In summary, we validated a novel 3XTg-iHAP mouse liver wound-healing model. The Mfge8 gene is constitutively expressed in the bile duct epithelial cells under the normal physiological condition, while upregulated in hepatocytes in response to the apoptosis-induced injury and repair. Our results suggest that liver wound healing is associated with an increase in Mfge8 expression in hepatocytes. The underlying mechanisms of whether and how MFG-E8 promotes the liver wound healing process need to be further studied.

Grants are supported by NIH and the U.S. Department of Veterans Affairs.

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 fictional animal project: A flexible tool for helping students learn physiology
Authors: Beason-Abmayr Beth
Published: May 2023

Several years ago, my colleagues and I developed a project-based assignment where students create a fictional animal and predict its ability to thrive in a hypothetical environment by examining the interactions between different combinations of designs for selected body systems. This assignment, which was implemented at different types of institutions and for different levels of students, can be readily adapted to either lecture-based or laboratory courses. Here I describe how students design a fictional animal as a semester-long collaborative group project in an interactive lecture course on comparative animal physiology of vertebrates. The fictional animal project aligns with several course learning goals including 1) Acquire a fundamental knowledge of “how animals work” and 2) Exercise responsibility and teamwork. Students learn integration of body systems as they choose a random fictional animal, consider if this animal can survive in a specific environment, and create the animal. Creation of the animal, which cannot closely resemble an extant animal, is scaffolded throughout the semester as students complete question sets where they describe the structure and function of the systems and consider potential trade-offs and physiological constraints. At the end of the semester, we hold a fictional animal showcase where students share highlights about their animal and its environment. Student learning is assessed through the questions sets, which are submitted as homework, and the class presentation; this group project contributes to 25% of the overall course grade and replaces more traditional assessments such as exams. Examples of fictional animals demonstrate how students must consider interactions and functions between different systems in their design; in addition, they must think about the metabolic requirements of their animal as they decide its lifestyle. Reflection data from students strongly supports that designing a fictional animal helps them understand how physiological systems function together; students gain a new or deeper awareness and appreciation of trade-offs in function as well as constraints on physiological processes. As this project continues to evolve, students will have the freedom to choose a creative format for the fictional animal showcase, such as a recorded or live oral presentation, a podcast, a tri-fold brochure, a poster, an educational game, or an illustrated story.

All protocols were approved by Rice University IRB (Protocol FY2017-294). Rice University Office of Undergraduate Research and Inquiry (OURI).

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 cells derived from elephant seals blunt angiogenic transcriptional signaling during hypoxia exposure
Authors: Allen Kaitlin , Torres-Velarde Julia Maria , Vázquez-Medina José Pablo
Published: May 2023

Northern elephant seals ( Mirounga angustirostris) conduct repeated deep dives, during which arterial blood oxygen becomes depleted. Interestingly, elephant seals require little surface recovery time from these dives, and extreme hypoxemia occurs regardless of dive duration or purpose. Recent in vitro and in silica work indicates that tight regulation of the canonical hypoxia response may protect diving seals against the inflammatory injuries typically associated with repeated hypoxia exposure. In vivo assessments of these phenomena, however, remain restricted due to both technical constraints and animals' inaccessibility while diving at sea. We developed a proliferative endothelial cell culture system from expelled placental arteries to assess the real-time molecular response to hypoxia exposure in northern elephant seals. Hypoxia inducible factor 1a (HIF-1a) protein localized to the nucleus within 1 h of exposure to 1% O2 in both species[KA1]. Hypoxia increased HIF-1a protein levels to a maximum of ~70-fold over (normoxic) baseline levels in both seal and human cells (p=0.005 for both species), though the response dynamics differed between species. HIF-1a abundance in seal cells was biphasic, with an initial rapid peak occurring within 15 min of hypoxia onset. In contrast, HIF-1a levels did not peak in human cells until 1 h in hypoxia and abundance declined continuously following this peak. Interestingly, RNAseq analysis of HIF-1a target gene expression suggested that seal cells blunt angiogenic signaling and vascular remodeling during hypoxia exposure despite sustained HIF-1a protein stabilization. Seal cell expression of STC2, NHE1/SLC9A1, and PFKL lagged behind expression of these genes in human cells during hypoxia exposure, and seal cell expression of ANGPT2 and MMP14 remained stable during long term hypoxia exposure, while expression of these genes was variable or high in human cells. Cis-regulatory analyses suggested a role for altered metabolism (rather than altered oxygen delivery) in seal cells during hypoxia via FOXK1, NFKB1, JUN and ZBTB7A. In contrast, the transcriptional signature in human cells suggests altered expression of oxygen delivery pathways via homeobox A13 (HOXA13), FOS like 1 (FOSL1) and SRF, all of which regulate angiogenesis, vascular remodeling and vasodilation. Together, these data suggest that seal endothelial cells respond to hypoxia by managing metabolic factors rather than calling for increased oxygen delivery despite rapid and sustained HIF-1a stabilization.

NSF GRFP and UC Berkeley startup

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.
Association of Osteogenic Adaptation and Sport Training in Distance Running, Soccer and Volleyball
Authors: Rocha-Rangel Jose , Rocha-Rangel Jose , Auslander Alexandra , Liang Michael , Tsai Anderson , Robles Patricia , Kwoh Yuan-Lieh , Arnaud Sara
Published: May 2023

Purpose: The purpose of the study was to determine whether sports training comprising of 1) high-impact loading sport in volleyball (VOL), 2) odd impact loading sport in soccer (SOC), and 3) low impact sport in distance running (RUN) were associated with weight bearing tibial bending strength and calcaneus BMD, and non-weight bearing ulnar bending strength and distal radius and ulna (wrist) BMD. Method: Female athletes comprised of 13 VOL, 22 SOC and 22 RUN participated in the study. A group of 23 non-athletes (NA) served as the comparison group. Tibial and ulnar bending strength ( EI, Nm2) were assessed using a mechanical response tissue analyzer (MRTA). Calcaneus and wrist BMD were assessed using a peripheral X-ray absorptiometry. Group means differences among the study groups were determined using ANCOVA with weight, height, body mass index, ethnicity/race, and training history serving as covariates, and Tukey post-hoc test to determine the sources of the difference. Results: Tibial EI of VOL (228.3 ±138 Nm2) and SOC (208.6 ±115 Nm2) were higher (p < 0.05) than NA (101.2 ± 42 Nm2), but not RUN (144 ± 110 Nm2). Ulnar EI of VOL, SOC and RUN (43.6 ± 17, 54.9 ± 51, 33.6 ± 15 Nm2, respectively) were higher (p < 0.05) than NA (27.2 ± 9 Nm2), not among the athletic groups. Calcaneus BMD of VOL (.618 ± .0.12 g/cm2), SOC (.621 ± .009 g/cm2), and RUN (.572 ± .007 g/cm2) were higher (p<0.05) than NA (.501 ± .08 g/cm2), not among the athletic groups. Wrist BMD of VOL (.484 ± .06 g/cm2) and SOC (.480 ± .06 g/cm2) were higher (p < 0.05) than NA (.443 ± .04 g/cm2). Conclusion: The most effective mode of musculoskeletal loading activity for developing tibial bending strength and calcaneus and wrist BMD is from VOL and SOC training.

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.
Increased dose and duration of infection with human adenovirus serotype 5 shifts amino acid, nucleic acid, TCA, and carbohydrate metabolism in human kidney cells
Authors: Sanchez Bailey-J , Grasis Juris , Fiehn Oliver , Ortiz Rudy
Published: May 2023

Viruses are obligate intracellular parasites that overtake host cellular processes and establish an environment optimal for replication. Human adenoviruses are double stranded DNA viruses known to possess a unique tissue tropism including respiratory, gastrointestinal, ocular, and renal tissues. Furthermore, infection can result in mild to moderate symptoms with increased severity in those with dampened immunity. Disruptions to host metabolism is a well-known consequence of viral infection. Nonetheless, the relationship between adenoviruses and host metabolism remains a largely unelucidated area. Few studies have coupled metabolomic techniques with the examination of infection across the adenoviruses’ range of tissue targets. Fewer studies have investigated metabolic shifts with manipulation of viral dosage and duration of infection simultaneously. The objective for this study was to determine metabolic shifts in human kidney cells with different dosages of human adenovirus serotype 5 and couple this to duration of infection. It was hypothesized that prolonged viral infection with increased viral dosage would result in greater shifts in metabolites involved in amino acid metabolism, carbohydrate metabolism, nucleotide metabolism, and the tricarboxylic acid cycle. Three dosages of human adenovirus serotype 5 were used: 0.5. 1.0, and 2.0 multiplicity of infection. Infections were prolonged for 6, 12, 24, and 36 hours and cytosolic fractions were subsequently collected. Samples were then subjected to gas chromatography coupled to time-of-flight mass spectrometry. We found distinct separations in many primary carbon classes between uninfected controls and infected cells. Greater separation was seen in the higher dosed samples compared to the 0.5 MOI group. Analyses revealed 186 identified metabolites with significant upregulated and downregulated metabolites involved in nucleotide biosynthesis, amino acid metabolism, carbohydrate formation, and tricarboxylic acid cycle. Metabolites such as urea and pyrophosphate displayed the greatest degree of upregulation and downregulation, respectively. This was evident across all concentrations at 24 HPI. An increase in duration of infection was correlated with the emergence of more metabolites, with greater detection at increased viral concentration. Our results identify specific metabolic pathways perturbed by viral-host interactions, which have not been previously implicated in adenoviral infection and in kidney cells. Our study also provides a framework to investigate individual adenoviral protein contribution to metabolic disruptions.

UC Merced USDA Hispanic Education Training Program Grant

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.
Intermittent hypoxic exposure and exercise training positively affect body composition and energy substrate utilization in high-fat diet-induced obese mice
Authors: Jang Inkwon , Park Yeram , Kyun Sunghwan , Hwang Deunsol , Yoo Choongsung , Park Hun-Young , Kim Jisu , Lim Kiwon
Published: May 2023

Obesity is considered a major risk factor for increasing insulin resistance and inducing type 2 diabetes. Exercise is known to be the most effective treatment for improving obesity and insulin resistance through body fat loss. Furthermore, hypoxic exposure is known to increase carbohydrate oxidation and improve overall energy expenditure. Therefore, in this study, the effect of combined treatment of exercise and intermittent hypoxia on body composition and metabolic improvement was investigated after inducing obesity through a high-fat diet.The male 5-week-old ICR mice consumed high-fat diet for 7 weeks and were fed ad libitum. After 7 weeks, all groups were randomly divided into 4 groups: CN (sedentary; non-trained), HP (hypoxic exposure; non-trained), EX (trained), and HE (hypoxic exposure and trained). The HP and HE were only exposed hypoxia condition (12% oxygen concentration) for during light phase to coincide with the mouse inactive cycle. The EX and HE conducted treadmill training with 5 times a week for 4 weeks, and the exercise intensity was 70 % of VO2 max. After 4 weeks, the resting metabolic rate (RMR) was measured for all groups through respiratory gas. Then, all mice conducted dual energy X-ray absorptiometry to determine body composition.In body composition results, long-term exercise treatment showed a significantly decrease in fat mass and a significant increase in lean mass. In addition, in the HE, had significantly lower body fat mass and significantly higher lean mass than the EX. Furthermore, in the RMR results, it was investigated that overall energy expenditure increased through an increase in VO2 and VCO2 in the exercise group. However, in the HE, it was confirmed that carbohydrate oxidation at rest was significantly higher than that of the EX. In addition, it was confirmed that fasting blood glucose and HOMA-IR, an indicator of insulin resistance, were also significantly improved in the HE than in the EX.In summary, these results demonstrated that long-term exercise training decrease fat mass and increase in lean mass in high-fat diet-induced obese mice. In addition, it was confirmed that the HE, which intermittent hypoxic exposure combined treatment with exercise, significantly improved body composition compared to the EX, as well as improved carbohydrate oxidation at rest, fasting blood glucose, and HOMA-IR.

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.
B1-adrenergic blockers preserve motor function by inhibiting the production of extracellular traps
Authors: Bourcier Camille , Michel-Flutot Pauline , Emam Laila , Adam Lucille , Gasser Adeline , Vinit Stephane , Mansart Arnaud
Published: May 2023

Sepsis is characterized by a dysregulated host response to an infection, potentially leading to fatal organ dysfunctions. Among these organs, the central nervous system (CNS) is particularly affected with encephalopathies associated or not with chronic disabling pain. These symptoms are caused by broad neuroinflammation with activation of resident microglia cells and infiltration of leukocytes, especially neutrophils. These immune cells have the ability to produce extracellular traps (ETs) in blood and tissues. These components are composed of chromatins and various antimicrobial proteins, and its role is to capture and destroy pathogens. However, in case of excessive production, deleterious effects occur such as tissue damage and reduction of neuronal excitability.In this study, the objectives were: 1) to determine whether in a model of endotoxemic shock, neutrophils and microglia form ETs in the CNS; 2) and to determine if a modulation of ETs production was beneficial on neuromuscular disorders associated with endotoxemic shock.We observed an infiltration of neutrophils in the SNC, an activation of microglia and a production of ETs following intraperitoneal lipopolyssacharide (LPS) administration in mice (adult Swiss male, 30-45g). Atenolol, a β1-adrenergic blocker with intrinsic immunomodulatory properties, significantly decreases the production of ETs associated in both microglia and neutrophils (citrullinated histone H3: 279.1 ± 101.9 MFI versus 117.1 ± 77.21 MFI, p<0,01). In addition, this treatment preserved the gastrocnemius motoneurons excitability (39,93 ± 15,16 mV in control group, 8.147 ± 5.892 mV in LPS group and 27.32 ± 10.73 mV in LPS+atenolol group). Similar results have been observed when the production of ETs was prevented by using sivelestat (inhibitor of extracellular traps).In conclusion, our results demonstrate that sepsis increases neutrophil infiltration into the spinal cord, activates immune cells and produces extracellular traps that directly impair motor function. Prevention of ETs formation partly restores motor function and could be a good target in order to reduce adverse effects in sepsis but also in other motor related pathologies.

This work was supported by funding from the Chancellerie des Universites de Paris (Legs Poix), INSERM and Paris-Saclay University-UVSQ.

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.
Plasma Insulin level have linkage with neurodegeneration in patients with type 2 DM
Authors: Shamansurova Zulaykho , Saatov Talat , Srivastava Ashok , Alimov Timur , Ibragimova Elvira , Ibragimov Zafar , Maksutova Nigora , Aikhodjaeva Mokhira , Ishankhodjaev Tokhir , Mustafakulov Mukhammadjon
Published: May 2023

Introduction: Type 2 Diabetes Mellitus (DM2) viewed as a major cause for neurodegenerative and cognitive abnormalities. One of the possible reason for that should be insulin resistance and hyperinsulinemia two main clinical future of DM2. The mechanism relationship between insulin and development of diabetic neuropathy and encephalopathy not clear yet. Material and methods: In 51 DM2 patients in age between 42 and 64 years old, without neurologic complications or with presence of different stages of neuropathy/encephalopathy were observed clinically and diagnosis confirmed by neurologist. Patients divided into two groups according to presence of mild and severe neuropathy or encephalopathy. For lab study cubital venous blood plasma taken for measure of plasma insulin level by ELISA. Results: Neuropathy/encephalopathy were registered in 71% of DM2 patients. HbA1c level were higher than healthy subjects and were comparable in both groups with severe neuropathy/encephalopathy and without. Blood plasma insulin level were between 14 and 21,7 μU/ml, significantly higher than normal ranges (0,7 – 9,07 μU/ml). Plasma insulin level were decreased according to severity of neuropathy/encephalopathy, and suggested about linkage between functional activity of beta-cells and neurodegeneration. Index HOMA-B indicates decreasing of beta-cells functional activity. Index Caro (glucose to insulin ratio) also been decreased and suggested about insulin resistance in these patients. When we analysed blood plasma insulin level according to presence and severity of diabetic neuropathy and encephalopathy there was significant Conclusion: Neurodegeneration is a frequent future of DM2 and were found in 71% cases. Presence and severity of neurodegeneration in DM2 have negative linkage with plasma insulin level and suggest about involvement of insulin resistance into pathogenesis of neurodegeneration.

no funding or 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.
Signal transduction pathways of muscarinic receptors in the murine urinary bladder smooth muscle
Authors: Balla Helga , Borsodi Kinga , Örsy Petra , Horváth Béla , Molnár Péter József , Ruisanchez Éva , Nyirády Péter , Wess Jürgen , Offermanns Stefan , Benyó Zoltán
Published: May 2023

Overactive bladder (OAB) is a clinical condition characterized by symptoms of frequency, urgency with/without incontinence. Despite of the fact that OAB affects millions of patients’ quality of life significantly, its etiology is still poorly understood. Currently, antimuscarinics are the first-line medical therapy for the management of OAB. However, their application is limited due to the decrease of patients’ compliance because of several adverse effects (e.g. dry mouth, obstipation).Our aim was to further analyze the signaling pathways of muscarinic receptors in detrusor muscle contraction with the goal of better understanding the intracellular regulation of micturition and identifying potential novel therapeutic targets for OAB.Experiments were performed on adult, male, wild-type (WT), M2, M3, M2/M3, Gαq/11 knockout (KO) and pertussis toxin (PTX)-treated mice. Contraction force and RhoA activity were measured in the urinary bladder smooth muscle (UBSM).Contractile responses induced by the muscarinic receptor agonist carbamoylcholine (CCh) in UBSM associated with increased activity of RhoA and were reduced in the presence of the Rho-associated kinase (ROCK) inhibitor Y-27632. The CCh-induced contractions were markedly reduced in detrusor strips lacking either M2 or M3 receptors and were abolished in UBSM from M2/M3 KO mice. The RhoA activation was decreased in both M2 KO and M3 KO bladders and it was completely reduced in M2/M3 KO UBSM. Inhibition of Gαi-coupled signaling by PTX-treatment shifted the concentration-response curve of CCh to the right and diminished RhoA activation. CCh-induced contractile responses were markedly decreased in Gαq/11 KO mice, however, RhoA activation was unaffected.In conclusion, cholinergic detrusor contraction and RhoA activation are mediated by both M2 and M3 receptors. Furthermore, CCh-induced contractions involve simultaneously the classical Gαq/11- and the Gαi-coupled signaling pathways, but the RhoA activation appears to be mediated exclusively by the Gαi proteins. These findings may aid the identification of more specific therapeutic targets for OAB.

Hungarian NRDIO K-125174, K-135683, K-139230 and PD-132851, Ministry for Innovation and Technology from the Hungarian NRDI fund (2020-1.1.6-JÖVÖ-2021-00010, TKP2021-EGA-25), STIA-KFI-2021, EFOP-3.6.3-VEKOP-16-2017-00009 grants and Gedeon Richter Plc Talent Foundation

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 salt intake during pregnancy and reno-cardiovascular disease in the offspring of C57Bl/6J mice
Authors: Ehmke Heimo , Seniuk Anika , Wageringel Isabel
Published: May 2023

Background: In 1989, Barker et al. reported that a low birth weight is associated with a higher incidence of death from cardiovascular disease later in life. While this seminal observation resulted in a surge of experimental and clinical research, the precise mechanisms underlying this association remain incompletely understood. A reduction of tolerogenic CD8+CD122+ T cells and an increase of cytotoxic CD8+ T cells by midgestational stress have been shown to cause fetal growth restriction, suggesting that immunological mechanisms may contribute to fetal programming of cardiovascular disease. Recent findings ascribe immunological processes a decisive role in the pathogenesis of arterial hypertension. There is strong evidence that both, the innate and the adaptive immune system contribute to full development of hypertensive blood pressure levels and consecutive end-organ damage. Salt intake is a major modulator of the immune system. An increased salt intake promotes the induction of pathogenic murine and human TH17 cells, predisposing to the development of salt-dependent hypertension. Intriguingly, a low birth weight is also associated with a high incidence of chronic kidney disease in adulthood, a major risk factor for cardiovascular disease. Hypothesis: A high salt intake during pregnancy induces fetal programming of cardiovascular and renal disease by an alteration of the feto-maternal immune crosstalk. Methods and Results: Pregnant C57Bl/6J mice were exposed to a high salt diet starting at conception until weaning of the offspring. Aged offspring (>1 year) was then exposed to a second cardiovascular hit (high salt intake without and with additional angiotensin II infusion). Quantitative immune cell analysis, telemetric blood pressure measurement, determination of renal function as well as histopathological analysis did not reveal any significant differences between offspring from normal salt fed dams and high salt fed dams. Conclusions: Our results do not support a major role of perinatal high salt intake on fetal programming or the risk for development of cardiovascular and renal disease in later life.

The study was financed by institutional budget.

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.
Effects of white adipose tissue denervation on baroreflex and inflammation markers in an experimental model of overweight
Authors: Nishi Erika , Milanez Maycon , Veiga Amanda , Campos Ruy , Bergamaschi Cassia
Published: May 2023

Several neurohumoral factors contribute to cardiovascular dysfunction in obesity. In this study, we tested the influence of retroperitoneal white adipose tissue (rWAT) innervation on baroreflex control of blood pressure, inflammation in target organs and renal function markers in an experimental model of overweight in rats with increased sympathetic drive. Wistar rats were treated with high-fat diet (HFD) for 8 weeks and underwent surgical rWAT denervation (DNX) at 6 weeks (n=6/group). At the end of the experimental protocol, we found that DNX improved reflex bradycardia (HFD: -1.76 ± 0.19, HFD+DNX: -2.76 ± 0.20, Control: -2.36 ± 0.12 bpm/mmHg) and decreased hepatic and splenic proinflammatory cytokines in the HFD group. Moreover, serum angiotensinogen (HFD: 112 ± 10 vs HFD+DNX: 84 ± 12 uM) and leptin (HFD: 9.8 ± 1.2 vs HFD+DNX: 5.2 ± 0.8 ng/dL) were decreased after DNX. No change was found in renal cytokines or function markers. Therefore, these findings suggest that neural signaling from the rWAT contributes to cardiovascular changes and inflammation in target organs in rats treated with HFD.

CAPES, CNPq and FAPESP

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.
Vitamin D mediated mitigation of fibrotic remodeling in asthma is associated with metabolic reprogramming
Authors: Ramakrishnan Rakhee , Kalaji Zaina , Bajbouj Khuloud , Halwani Rabih , Hamid Qutayba
Published: May 2023

Vitamin D mediated mitigation of fibrotic remodeling in asthma is associated with metabolic reprogramming Rakhee K. Ramakrishnan1, Zaina Kalaji1, Khuloud Bajbouj1, Rabih Halwani1,2, Qutayba Hamid1,3 1 Sharjah Institute for Medical Research – College of Medicine, University of Sharjah, Sharjah, United Arab Emirates 2 Immunology Research Lab, College of Medicine, King Saud University, Riyadh, Saudi Arabia 3 Meakins-Christie Laboratories, McGill University, Montreal, Quebec, CanadaAsthma is a heterogeneous disorder that is associated with chronic airway inflammation and remodeling of the airways. While vitamin D deficiency has shown correlations with various clinical features of asthma, the mechanisms responsible for this action is poorly understood. This study therefore explored the molecular mechanisms associated with the anti-remodeling potential of vitamin D. We hypothesized that vitamin D induced metabolic reprogramming contributes to its anti-fibrotic activity. To this end, primary lung fibroblasts from asthmatic and non-asthmatic individuals were stimulated with TGF-β1 alone or in combination with the biologically active form of vitamin D, calcitriol. The expression of various fibrotic and metabolic markers was assessed both at the transcript and protein level. While vitamin D receptor (VDR) was constitutively expressed in human lung fibroblasts, calcitriol treatment induced a robust VDR response in asthmatic fibroblasts indicating increased VDR functionality in these cells when compared to normal. TGF-β1 stimulation led to an increase in the expression of several fibrotic markers, including COL1A1, COL3A1, COL5A1, FN1 and ACTA2, which was reversed after calcitriol treatment. These anti-fibrotic effects of calcitriol were associated with dysregulated AMPK signaling and an inhibition of TGF-β1-induced mitochondrial ROS release. Our findings thus, highlight the ability of vitamin D in regulating the cellular mitochondrial metabolism induced by TGF-β1 in lung fibroblasts, suggesting a possible mechanism associated with its anti-fibrotic activity. Since current asthma therapeutics do not effectively target the airway structural changes that are increasingly associated with asthma severity, vitamin D supplementation presents an attractive therapeutic avenue to attenuate subepithelial fibrosis and airway remodeling in asthmatic airways.

We would like to acknowledge the funding received from University of Sharjah targeted research grant (ID 2101090295) in conducting this study.

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.
Selective alpha 1-adrenergic blockade attenuates resting beat-to-beat blood pressure variability in healthy young men
Authors: Vianna Lauro , Rodrigues Gustavo , Daher Mauricio , Teixeira Andre , Fernandes Igor
Published: May 2023

Resting beat-to-beat blood pressure variability is a powerful predictor of cardiovascular events and end-organ damage. However, its underlying mechanisms remain incompletely understood. For instance, alterations in beat-to-beat blood pressure variability are thought to be driven by changes in both the reflex control of the autonomic nervous system and peripheral vascular function. To determine the role of peripheral sympathetic vasoconstriction on the beat-to-beat blood pressure variability, beat-to-beat heart rate (HR, by electrocardiography) and blood pressure (finger photoplethysmography) were continuously measured in seven healthy men (22 ± 5 yr) at rest (supine position), with and without (Control) a systemic and selective blockade of alpha 1-adrenergic receptors through the oral administration of Prazosin (1 mg/20 kg of body weight). Stroke volume was estimated from the blood pressure waveform (ModelFlow), permitting the calculation of cardiac output and total peripheral resistance. Two hours post-Prazosin ingestion, blood pressure responses to intravenous bolus infusion of phenylephrine were robustly reduced (-80 ± 15%, P = 0.001), indicating a significant functional blockade of alpha 1-adrenergic receptors. However, all resting hemodynamic variables were unchanged after the oral ingestion of Prazosin. Compared with control, Prazosin significantly reduced the standard deviation of systolic (5.5 ± 0.9 vs. 3.7 ± 0.7 mmHg, P = 0.004), diastolic (3.3 ± 1.0 vs. 2.4 ± 0.6 mmHg, P = 0.05), and mean blood pressure (3.7 ± 0.8 vs. 2.5 ± 0.5 mmHg, P = 0.02), as well as cardiac output (652 ± 251 vs. 428 ± 78 mL/min, P = 0.02) and total peripheral resistance (1.1 ± 0.6 vs. 0.5 ± 0.4 mmHg/L/min, P = 0.03). Similar results were found using different indices of blood pressure variability. Altogether, these findings suggest that peripheral sympathetic vasoconstriction plays a pivotal role in modulating resting beat-to-beat blood pressure variability in healthy young men.

National Council for Scientific and Technological Development (CNPq; grant: 307293/2019-0 and 431740/2018-6).

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.
Glucagon activates NCC in a glucagon receptor-dependent manner
Authors: Poulsen Søren , Baungaard Sara , Bourqui Laurent , Murali Sathish , Nørregaard Rikke , Loffing Johannes , Fenton Robert
Published: May 2023

Introduction: Glucagon is raised during hypoglycemia in order to bring blood glucose back to normal levels. However, glucagon is paradoxically also raised under pathophysiological conditions where plasma glucose is high such as in diabetes mellitus (DM). DM is associated with hypertension, which contributes to diabetic kidney disease and other co-morbidities. The NaCl cotransporter (NCC) in the renal distal convoluted tubule (DCT) contributes to blood pressure control and the DCT also expresses the glucagon receptor. Therefore, we hypothesized that glucagon directly stimulates NCC via the glucagon receptor, and this may be a novel mechanism to modulate blood pressure. Methods: In vivo effects on NCC were studied in mice injected with glucagon. Ex vivo kidney tubules isolated from mouse and human kidney (obtained from tumor nephrectomized patients) were cultured and exposed to varying doses of glucagon alone, or in the presence of various inhibitors. The phosphorylation status of NCC was used as a surrogate marker for activity (increased phosphorylation = increased activity). Results: In kidneys isolated from mice 30 min after being injected with glucagon, NCC phosphorylation was increased. In ex vivo mouse kidney tubules, glucagon (1 nM to 1000 nM) exposure for 30 min increased NCC phosphorylation in a dose-dependent manner. 10 nM glucagon increased NCC phosphorylation after 5 min, an effect lasting up to 4 h. The glucagon receptor inhibitor 168,049 completely blocked the effect of 10 nM glucagon on NCC phosphorylation. The With No Lysine kinase (WNK) inhibitor StockS2, the inward-rectifier potassium channel 4.1/5.1 (Kir 4.1/5.1) inhibitor VU0134992, and the non-specific protein kinase A (PKA) inhibitor, H89, greatly reduced the effect of 10 nM glucagon on NCC phosphorylation. NCC phosphorylation was also increased in ex vivo human kidney slices exposed to 100 nM glucagon. Conclusion: We show for the first time that glucagon increases NCC phosphorylation in the mouse kidney both in vivo and ex vivo. The effect occurs via the glucagon receptor and involves WNK kinases, Kir4.1/5.1 and PKA. Glucagon effects can be observed ex vivo in human kidney slices, supporting that the findings may be relevant in humans. Whether glucagon-induced NCC phosphorylation contributes to the etiology of pathophysiological conditions manifested with raised plasma glucagon levels, such as DM, remains to be investigated.

Novo Nordisk Foundation (NNF21OC0067647) and the Leducq Foundation (17CVD05).

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 PCSK9 on endothelial efferocytosis in vascular aging
Authors: Ding Zufeng , Liu Shijie
Published: May 2023

Background and Aims: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease that binds to low-density lipoprotein receptors. Efferocytosis is the process by which phagocytes remove apoptotic cells. Both PCSK9 and efferocytosis play important roles in regulating redox biology and inflammation, the key factors contributing to vascular aging. This study was designed to investigate the impact of PCSK9 on efferocytosis in endothelial cells (ECs) and its implications in vascular aging. Methods and Results: Studies were performed in primary human aortic ECs (HAECs) and primary mouse aortic ECs (MAECs) isolated from male wild-type (WT) and PCSK9-/- mice, and in young and aged mice treated with saline or the PCSK9 inhibitor Pep2-8. Our findings include that recombinant PCSK9 protein treatment induces defective efferocytosis and aging marker senescence-associated-β-galactosidase (SA-β-gal) expression in ECs, while PCSK9-/- restores efferocytosis and inhibits SA-β-gal activity. Further studies in aged mice showed that endothelial deficiency of MerTK, a critical receptor for efferocytosis that allows phagocytes to detect the presence of apoptotic cells, may be an indicator for vascular dysfunction in the aortic arch. Pep2-8 treatment markedly restored efferocytosis in endothelium from the aged mice. A proteomics study in the aortic arch from aged mice showed that PCSK9-/- significantly downregulates expression of NOX4, MAPK subunits, NF-κB, and secretion of pro-inflammatory cytokines, all known to promote vascular aging. Conclusions: These findings provide first evidence for the ability of aortic ECs to accomplish efferocytosis, and a role of PCSK9 in attenuating EC efferocytosis, leading to vascular dysfunction and acceleration in vascular aging.

This work was supported by the National Institutes of Health, including National Institute on Aging (R21AG075548) and National Heart, Lung, and Blood Institute (R01HL162958). The work was also partially supported by the UAMS Bronson Endowment Foundation Award, VCRI Equipment Grant and Shared Resources Voucher Award.

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.
Spinal NMDA receptor activation is necessary to initiate but not maintain ampakine-hypoxia induced phrenic motor facilitation
Authors: Thakre Prajwal , Perim Raphael , Mitchell Gordon , Fuller David
Published: May 2023

Ampakines are a class of compounds which act as positive allosteric modulators of AMPA receptors. Intravenous (i.v.) delivery of a “low impact” ampakine prior to a single brief hypoxic episode produces a persistent (≥60 min) increase in phrenic nerve output (i.e., phrenic motor facilitation, pMF) (Thakre et al., J. Neurophysiol., 2021). Many forms of synaptic plasticity require an interplay of AMPA and NMDA receptors, including hippocampal long-term potentiation and acute intermittent hypoxia (AIH) induced long-term facilitation (LTF) in the phrenic motor system. Here, we tested the hypothesis that spinal NMDA receptor activation is necessary for pMF induced by a combination of ampakine and a single brief hypoxic episode (A+H). Phrenic nerve recordings were made from an experimental preparation that enables rigorous arterial blood gas control: urethane-anesthetized, ventilated, paralyzed and vagotomized adult male Sprague-Dawley rats. Ampakine CX717 (15 mg/kg, i.v.) was delivered 2-min prior to a 5-min hypoxic episode (partial pressure of arterial O2 ~40 mmHg). In experiment 1, the NMDA receptor antagonist MK-801 (10 μM) or vehicle (physiological saline) was intrathecally delivered at spinal segment C4 prior to A+H. Vehicle treated rats demonstrated greater phrenic burst amplitude at 60-min post-hypoxia (burst amplitude = 47±1 %BL) versus MK-801 treated rats (11±1 %BL; 2-way repeated measures analysis of variance, RM ANOVA, treatment effect, P=0.02, n=5 per group). In experiment 2, intrathecal MK-801 or vehicle (n=5 per group) were delivered 20-min after A+H. Neither MK-801 nor vehicle impacted pMF magnitude (2-way RM ANOVA, treatment effect, P=0.6). We conclude that the induction, but not maintenance, of A+H-induced pMF requires spinal NMDA receptor activation in contrast with AIH-induced phrenic long-term facilitation, which requires NMDA receptor activation for its maintenance (but not initiation). We reveal a novel mechanism of phrenic motor plasticity akin to hippocampal activity-induced synaptic plasticity, which requires NMDA receptor activation for initiation, but not maintenance. We suggest that ampakine pretreatment may have value in boosting the therapeutic impact of hypoxia-based neurorehabilitation strategies (Gonzalez-Rothi et al., J. Appl. Physiol., 2015).

R01 HL139708 02

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.
Shorter hypoxic and inter-hypoxic intervals enhance acute intermittent hypoxia-induced phrenic long-term facilitation
Authors: Burrowes Kayla , Marciante Alexandria , Mitchell Gordon
Published: May 2023

Phrenic long-term facilitation (pLTF) is a form of respiratory motor plasticity evoked by repeated exposure to low oxygen (acute intermittent hypoxia; AIH). AIH has emerged as a promising therapeutic approach to restore lost respiratory and non-respiratory function in people with spinal cord injury and other clinical disorders that compromise movement. Optimal AIH protocols ( e.g. episode severity/duration and number of hypoxic episodes) to elicit plasticity (and therapeutic benefit) have not yet been established. Three, 5-minute moderate hypoxic episodes with 5-minute intervals have been used most often to study pLTF. New data suggest that the same cumulative duration of hypoxia ( i.e. 15 min), when presented in shorter episodes, enhances pLTF by minimizing hypoxia-evoked adenosine release. Although the “standard” AIH protocol can be improved by reducing the duration of hypoxic episodes, little attention has yet been given to the duration of inter-hypoxic intervals. Thus, we began investigations concerning the impact of interval duration and episode number in moderate AIH protocols (mAIH; arterial PO2 = 40-55mmHg). pLTF was assessed in anesthetized, paralyzed, vagotomized and ventilated male Sprague-Dawley rats exposed to mAIH consisting of: 1) 3, 1 minute hypoxic episodes (3x1) with either 5-, 2- or 1-minute inter-hypoxic intervals; or 2) 2, 5-minute hypoxic episodes with a single 15-minute interval, compared with the conventional protocol (3, 5 minute hypoxic episodes, 5 minute intervals). mAIH consisting of 3x1, 5-min intervals elicit similar pLTF versus 3, 5 min episodes with 5-min intervals (64 ± 7% and 64% ± 1%, respectively; both n=3) at 60 minutes post-hypoxia. Thus, shorter intervals in an otherwise similar mAIH protocol consisting of 3x1 minute hypoxic episodes significantly enhance pLTF (1-minute: 146 ± 15%, n=5; 2 minute: 92 ± 17%, n = 3). Two, 5-minute hypoxic episodes with a single 15-minute inter-hypoxic interval still elicited pLTF of 51 ± 26% (n=4). These preliminary findings suggest both the hypoxic episode and interval duration are important determinants of mAIH-induced pLTF. Optimizing AIH-induced motor plasticity is necessary as we harness its therapeutic potential to treat severe neuromuscular disorders that compromise breathing.

Supported by: NIH HL147554, HL148030, T32HL134621 (ABM)

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.