bluuebunny/crossref_metadata_2025 huggingface dataset:
Intact DNA Repair in Differentiated Cardiomyocytes Is Essential for Maintaining Cardiac Function in Response to Pressure Overload in Mice
Authors: de Boer Martine , Hoeijmakers Jan H.J. , Duncker Dirk J.
Published: May 2024

Introduction: DNA in every cell is continuously damaged and DNA repair mechanisms are essential for protection against DNA damage-induced aging-related diseases. For example, deficient repair of endogenously generated DNA damage in mice with cardiomyocyte-restricted inactivation of Xpg, is associated with progressive heart failure (de Boer et al. Aging Cell 2023). Here we tested the hypothesis that unrepaired DNA damage in differentiated cardiomyocytes increases cardiac vulnerability in response to hemodynamic overload. Methods: At 8 weeks of age, αMHC-Xpgc/- and control (Ctrl) mice were subjected to pressure overload by mild transverse aortic constriction (TAC). Eight weeks after TAC, left ventricular (LV) function was assessed using echocardiography and hemodynamic measurements, followed by histological and molecular analyses. Results: Cardiomyocyte-restricted inactivation of Xpg resulted in systolic as well as diastolic LV dysfunction. TAC-induced LV hypertrophy was similar in both groups (Ctrl 38%; αMHC-Xpgc/- 34%). In Ctrl mice, LV hypertrophy was accompanied by minimal LV dilation and only modest changes in systolic and diastolic LV function. Conversely, TAC in αMHC-Xpgc/- produced severe LV dilation and dysfunction and resulted in overt backward failure, demonstrated by marked increases in LV end-diastolic pressure, left atrial weight and lung fluid weight. These changes were accompanied by further increases in the expression levels of the hypertrophic marker genes atrial natriuretic peptide and beta-myosin heavy chain. Moreover, lectin staining revealed a decrease in capillary density and TUNEL staining revealed further elevated levels of myocardial apoptosis in αMHC-Xpgc/--TAC mice as compared to Ctrl-TAC mice. In addition, a significant increase of myocardial collagen content was observed in αMHC-Xpgc/--TAC but not in Ctrl-TAC mice. Conclusion: Cardiomyocyte-restricted loss of DNA repair protein Xpg increases cardiac vulnerability to develop heart failure in response to pressure-overload. These findings underscore the importance of genomic stability for maintenance of cardiac function, not only under basal conditions, but also during increased cardiac loading conditions.

Supported by the Dutch Heart Foundation [Grants 2017B018-ARENA-PRIME; 2021B008-RECONNEXT].

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.
Activation of Piezo-1 Prevents Human Microvascular Endothelial Dysfunction During Acute Inhibition of Ceramide Formation
Authors: Jaramillo-Torres Maria Jose , Senthilkumar Gopika , Lindemer Brian , Bordas-Murphy Henry , Freed Julie K.
Published: May 2024

Despite the well-known damaging effects of elevated intracellular ceramides on human microvascular function, our recent work has shown that inhibition of ceramide formation through neutral sphingomyelinase (NSmase) promotes endothelial dysfunction in arterioles from healthy adults, manifested as endothelial production of hydrogen peroxide (H2O2), rather than nitric oxide (NO), in response to flow (flow-induced dilation; FID). Recent evidence suggests that ceramide prevents inactivation of Piezo-1, a shear-sensitive Ca2+ channel and inhibition of Piezo-1 reduces endothelial nitric oxide synthase (eNOS) activation in response to flow. Together, we hypothesized that ceramide-induced Piezo-1 activation is required to maintain NO-mediated FID in human microvessels and thus agonism of Piezo-1 during NSmase inhibition will prevent endothelial dysfunction. Arterioles (100-250μm) from healthy adults were dissected from discarded surgical adipose tissue. Vessels were cannulated in organ chambers, pre-constricted with endothelin-1, and changes in internal diameter in response to increases in flow were measured with videomicroscopy. Peroxy yellow 1 (PY1) fluorescent probe was used to assess endothelial H2O2 production in human umbilical vein endothelial cells (HUVECs). Mean% maximal dilation or fluorescent intensity±SE with two-way repeated measures ANOVA is reported. FID was preserved with Piezo-1 agonism (Yoda-1, 1μM, 30min) during NSmase inhibition (GW4869 4μM, 30min; 73±16.8, n=4 vs control 73±8.2, n=9; p>0.05), however FID was diminished in the presence of the eNOS inhibitor L-NAME (100μM; -2.6±11.3, n=5; p<0.05). A similar switch to NO-mediated FID was seen with C2-ceramide (5μM)+GW4869 (70.1±9.7 vs +L-NAME -3±9.7, n=4 both; p<0.05). NSmase inhibition increased H2O2 production in HUVECs (5.2±7.4 vs 83.0±31.6, n=6; p<0.05), an effect that was diminished with Yoda-1 (5.1±7.5, n=4; p<0.05) and C2-ceramide (10.7±9.2, n=5; p<0.05). These data suggest a role for Piezo-1 in NSmase-induced NO-signaling and provide mechanistic insight into how ceramide may exert beneficial effects within the human microvasculature.

This research is supported by the National Institute of Health (NHLBI) R01HL160752 (JKF) and the American Heart Association (AHA) Predoctoral Fellowship 909315 (GSK).

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.
Involvement of heart-gut axis in endocannabinoid CB1R signaling following alcohol binge
Authors: Cohen Sarah , McTernan Patrick , Siggins Robert , Cinar Resat , Pacher Pal , Paloczi Janos
Published: May 2024

Introduction: Binge alcohol drinking is linked to an increasing number of emergency room visits and rising healthcare costs. We have recently shown that binge alcohol drinking is associated with the activation of cannabinoid receptor type-1 (CB1R) signaling, aggravating binge alcohol-induced cardiovascular dysfunction. The endogenous CB1R agonist, anandamide (AEA), can form in response to various stimuli including increased levels of circulating endotoxins derived from intestinal Gram-negative bacteria. Besides, increased levels of serum endotoxins can also provoke the activation of innate immune cells. However, it is still unclear if how AEA is formed in the cardiovascular system. Here, we studied the effect of intestinal Gram-negative bacteria-derived endotoxins on myocardial CB1R activation and aimed to identify the cellular source of AEA after alcohol binge. Methods: 8-12 week old C57BL/6J mice were orally administered a single ethanol binge at a dose of 5g/kg body weight, with or without prior treatment with non-absorbable antibiotics. Circulating endotoxins were assessed following alcohol binge. Intestinal-barrier permeability was assayed by using FITC-Dextran administration. Myocardial tissue endocannabinoid levels were measured by LC/MS. Immunostaining approaches were applied to determine the rate of oxidative stress in the myocardium. Left ventricle performance was assessed by using a pressure-volume catheterization approach. Tissue perfusion was also evaluated by laser speckle contrast imaging. Results: Alcohol gavage was associated with a time-dependent increase of serum endotoxins peaking 3h after intoxication. Selective intestinal decontamination significantly improved the gut barrier function following alcohol gavage which was concomitant with the decreased myocardial oxidative stress. Simultaneously, reduced levels of myocardial AEA and cardiovascular performance improvement were observed. Conclusion: Our findings underscore the potential role of Gram-negative flora derived substances in the modulation of cardiovascular endocannabinoid AEA levels following alcohol binge drinking, impacting cardiac function and oxidative stress.

Supported by Intramural Research Program of NIH/NIAAA; R00AA028300, LSUHSC start-up funds.

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.
Erythropoiesis related biomarkers to detect autologous blood micro-transfusion in antidoping field
Authors: Loria Francesco , Almeida Oliveira Jessica , Breenfeldt Andersen Andreas , Bejder Jacob , Bonne Thomas , Grabherr Silke , Kuuranne Tiia
Published: May 2024

Indirect detection of autologous blood transfusion (ABT) abuse in Anti-Doping world is done by hematological module of athlete biological passport (ABP). Actual markers (reticulocytes (%RET) and hemoglobin (HGB)) of this module are enough sensitive to detect ABT. However, a new way uses by athlete to improve their performance is micro ABT and in this case %RET and HGB have some lack of sensitivity to detect this new way of doping. Previous studies have demonstrated that erythropoiesis-related RNAs, genes 5’-aminolevulinate synthase 2 ( ALAS2) and carbonic anhydrase 1 ( CA1) in capillary dried blood spots (DBS) could be potential biomarkers to increased sensitivity of the ABP in case of micro-ABT. In the present study, we monitored ALAS2 and CA1 expression in DBS after a donation of 450ml of blood and after a micro reinfusion (130ml) of this blood. DBSs samples collected from 48 volunteers’ males and females were analyzed. Participants were divided in two groups (micro ABT and placebo). Before the beginning of the study, randomized volunteers from transfused and non-transfused cohort were monitored 2 or 8 times weekly to get baseline points. 5 samples were collected after the blood withdrawal and 6 samples after the micro-ABT. The purpose was to evaluate the performance of RNAs biomarkers for the detection of micro-ABT in a longitudinal blinded setting. Our results illustrated a clear significant increase of ALAS2 until to 300 % after withdrawal. Regarding CA1 the increase is up to 250%. Looking at micro-ABT ALAS2 and CA1 will decrease under the baseline value. Regarding actual ABP markers, %RET slightly increase after the withdrawal up to 140%. In contrast, micro-ABT seem to have any effect with value that came back to baseline value without decreasing under baseline value. Finally, HGB slightly decrease after withdrawal follow by any increase after micro-ABT. Oppositely, regarding placebo group RNA markers and actual ABP markers stay stable all along the study. Erythropoiesis-related RNAs in capillary DBS such as ALAS2 and CA1 were sensitive biomarkers for blood withdrawal detection followed by micro-ABT. Furthermore, this investigation provide evidence that micro ABT can be detected in a longitudinal blinded setting with RNA biomarkers in DBS.

World Anti Doping Agency.

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.
Neuroprotective Effect of Grewia carpinifolia Extract against Behavioral Impairments Induced by Vanadium
Authors: Obisesan Ayobami , Adebiyi Olamide , Olopade James , Olayemi Funsho
Published: May 2024

Vanadium is a heavy metal that has been reported to cause toxicity in the central nervous system resulting in various behavioral alterations. This is characterized by the generation of reactive oxygen species. The present study was designed to investigate the probability of Grewia carpinifolia ethanol extract in preventing behavioral impairments following acute vanadium toxicity in mice. Twenty five Swiss albino mice (25–27g) were randomized into 5 groups (A–E) of 5 animals each. Group A received distilled water and served as a control; group B received vitamin E (500mg·kg−1 b.w. every 72 hours), a known antioxidant orally along with a daily dose of sodium metavanadate intraperitoneally (i.p.) for 7 days; group C and group D received Grewia carpinifolia leaf extract at 100 and 200mg·kg−1 b.w orally respectively, along with the sodium metavanadate i.p. for 7 days; while group E received sodium metavanadate i.p. only for 7 days. The behavioral and motor functions were analyzed by the open field, negative geotaxis, and hanging wire tests; the daily body and brain weights were recorded. Grewia carpinifolia ethanol extracts significantly reduced the number of grooming, stretched attend posture, and freezing time that were significantly increased in the vanadium only group and also enhanced the vestibular functions. Furthermore, the latent time spent on the hanging wire in groups simultaneously administered with the extract and vanadium compared positively (P>0.05) with the control groups but a decrease in latent time was observed in the vanadium only group. The results suggest that acute vanadium toxicity results in various behavioral impairments and support a possible role of Grewia carpinifolia as a protective agent against acute vanadium-toxicity with a better result at 200mg·kg−1 b.w.

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.
WNK1 is a central osmolality sensor for arginine vasopressin release and acts through the OSR1/SPAK kinase cascade
Authors: Jin Xin , Xie Jian , huang chou-long
Published: May 2024

Background: Maintaining internal osmolality constancy and water homeostasis is essential for life. The circumventricular organs (CVOs) of the brain, including the organum vasculosum of the lamina terminalis (OVLT) and subfornical organ (SFO), lack a blood-brain barrier. Neurons in OVLT and SFO detect increases in serum osmolality that stimulate the production of vasopressin (AVP) in paraventricular nuclei (PVN) to be released in the posterior pituitary. We have recently reported that WNK1 in sensory neurons in CVOs functions as an osmolality sensor for AVP release (Jin et al., JCI, 2023). WNK1 activates Kv3.1 to increase action potential, traveling down to PVN to increase AVP synthesis for release from the posterior pituitary. Here, we propose that OSR1/SPAK acts as the downstream kinase for WNK1 in regulating AVP release. We further investigated the regulation of vasopressin release by the WNK1-OSR1/SPAK cascade in response to extracellular hyperosmolality. Methods: Cre recombinase-carrying retrograde AAV virus was stereotaxically injected into PVN nuclei from normal mice and SPAK-null mice with a homozygous OSR1-floxed allele (SAPK−/−;OSR1flox/flox). Metabolic cage studies were performed on mice. Urine output, water intake, serum osmolality, serum AVP, and copeptin levels were measured. K+ currents were measured from the OVLT neurons by whole-cell patch clamp. Results: Increased osmolality, either by water restriction or mannitol injection, activated OSR1/SPAK in OVLT, as evident by increased serine-373 phospho-SPAK and serine-325 phospho-OSR. Like the WNK1 deletion, the double deletion of OSR/SPAK in OVLT caused polyuria with decreased urine osmolality that persisted in water restriction. Circulating levels of AVP and copeptin were increased by water restriction in control mice. In contrast, water restriction failed to increase the levels in OSR/SPAK-deletion mice. Knockdown of the Kv3.1 channel in OVLT by shRNA showed the central diabetes insipidus (DI) phenotype as well. Hypertonicity increased K+ currents and WNKs inhibitor prevented the increase in OVLT neurons. Conclusions: Mice with neuronal-specific OSR1/SPAK deletion have water homeostasis defects consistent with partial central DI; Evidence supporting that OSR1/SPAK acts downstream of WNK1 to regulate AVP release; WNK1-OSR1/SPAK activates Kv3.1 to increase firing frequency of neurons projecting from CVOs to PVN. Our findings reveal that an intracellular protein acts as a sensor for extracellular tonicity and provide fresh insights into the mechanisms by which the body maintains osmolality constancy. Future studies will investigate how OSR1/SPAK regulates Kv3.1 channels.

NIDDK.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
The renal vasodilation from β-adrenergic activation in vivo in rats is not driven by KV7 and BKCa channels
Authors: Sorensen Charlotte , Salomonsson Max , Lubberding Anniek , Holstein-Rathlou Niels-Henrik
Published: May 2024

Aim: The underlying mechanisms behind β-adrenergic renal vasodilation is not clarified. Several classes of K+ channels are potentially activated, so we tested the hypothesis that voltage-sensitive KV7 and Ca2+-activated BKCa channels contribute to the decrease in renal vascular tone in vivo and in vitro. Methods: Changes in renal blood flow (RBF) during β-adrenergic stimulation was measured in isoflurane-anesthetized rats using an ultrasonic flow probe. The isometric tension of segmental arteries from normo- and hypertensive rats and segmental arteries from wild-type mice and mice lacking functional KV7.1 channels was examined in a wire-myograph. Results: The β-adrenergic agonist isoprenaline increased RBF significantly in vivo. Neither activation nor inhibition of KV7 or BKCa channels reduced the β-adrenergic RBF response. In segmental arteries from normo- and hypertensive rats, inhibition of KV7 channels significantly decreased the β-adrenergic vasorelaxation. However, inhibiting the BKCa channel was equally effective. The β-adrenergic vasorelaxation was not different between segmental arteries from wild-type mice and mice lacking a functional KV7.1 channel. As opposed to rats, inhibition of KV7 channels did not affect the murine β-adrenergic vasorelaxation. Conclusion: Although inhibition and activation of KV7 and BKCa channels significantly changed baseline RBF in vivo, none of the treatments affected the β-adrenergic vasodilation. In segmental arteries however, inhibition of KV7 and BKCa channels significantly reduced the β-adrenergic vasorelaxation indicating that the regulation of RBF in vivo is driven by several actors in order to maintain an adequate RBF. Our data stresses the importance of verifying data in intact animals.

None.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
The Cyst Epithelium in Polycystic Kidney Disease Patients Displays Normal Apical-Basolateral Cell Polarity
Authors: Loft Sandegaard Samuel , Riishede Andreas , Birn Henrik , Damkier Helle Hasager , Praetorius Jeppe
Published: May 2024

The main characteristic of polycystic kidney disease (PKD) is the development of multiple fluid filled renal cysts. The discovery of mislocated Na, K-ATPase in the apical membrane of cyst lining epithelia alluded to a reversal of polarity as a possible explanation for the fluid secretion. The topic of apical Na, K-ATPase in cysts remains controversial with some investigators finding conventional localization in cysts. Thus, we investigated localization of the Na, K-ATPase and assessed the apical-basolateral polarization of cyst lining epithelia by means of immunohistochemistry on tissue from six anonymous PKD patients undergoing nephrectomy. The Na, K-ATPase α1 subunit was conventionally situated in the basolateral membrane of all immunoreactive cysts. Proteins of the Crumbs and partitioning defective (Par) complexes were localized to the apical membrane domain in cyst epithelial cells. The apical t-SNARE protein Syntaxin-3 also immunolocalized to the apical domain of cyst lining epithelial cells. Proteins of the basolateral Scribble complex immunolocalized to the basolateral domain of cysts. Furthermore, we confirmed that cysts can originate from virtually any tubular segment with preserved polarity. In conclusion, we find no evidence of a reversal in apical-basolateral polarity in cyst lining epithelia in polycystic kidney disease.

This study was supported by Aarhus University Research Foundation(AUFF) AU-Ideas, and the Danish Council for Independent Research—MedicalSciences.

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.
Kidney disease associated with pre-pubertal obesity initiates pathological alterations in the brain of Dahl salt-sensitive rats
Authors: Bhopatkar Anukool A. , Mandal Sautan , Johnson Tyler , Williams Jan M.
Published: May 2024

Childhood/pre-pubertal obesity (PPO) is implicated in the development of chronic kidney disease (CKD), and there is evidence that PPO also increases the risk of developing Alzheimer disease (AD) later in life. In the current study, we aim to investigate the correlation between CKD and the development of AD-like pathology in a rat model of CKD associated with PPO. We hypothesize that systemic inflammation due to PPO exacerbates CKD and induces AD-like pathology in the brain at older age. In our preliminary studies, we utilized the Dahl salt sensitive leptin receptor mutant rat (SSLepRmutant), which is a novel model of PPO. 6-week-old Dahl salt-sensitive (SS) (control, n=3) and SSLepRmutant rats (n=5) were monitored for proteinuria every 3 weeks, for a 12-week period. Throughout the study, we observed significantly elevated proteinuria in SSLepRmutant rats (Week-6: 337±81 mg/day, Week-9: 371±147 mg/day, Week-18: 1920±318 mg/day) compared to SS rats (Week-6: 25±7 mg/day, Week-9: 35±39 mg/day, Week-18: 35±33 mg/day). At 18-week, creatinine levels were significantly higher in SSLepRmutant rats (1.5±0.5 mg/dL) versus SS rats (0.4±0.03 mg/dL) indicating CKD. Additionally, we found significant elevation of triglycerides in SSLepRmutant rats (5134±1211 mg/dL) compared to SS rats (79±21 mg/dL). To investigate the brain pathology, we performed immunochemical analysis (dot-blot assay) using A11 antibody to determine the levels of Amyloid-beta oligomers (Aβo). Our results show that there was tendency for Aβo levels to be increased in the brains from obese SSLepRmutant rats compared to SS. Finally, we tested the permeability of the blood-brain barrier to Evans blue dye and observed that the brain of SSLepRmutant rats was more permeable to the dye compared to SS rats as early as 8 weeks of age. Overall, these results indicate that PPO obesity not only increases the susceptibility to develop CKD but also causes Alzheimer-like pathology during the prepubescent stage.

NIDDK (DK109133) and AG (AG057842) awarded to Jan M. Williams.

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.
AM Insulinization of the Liver Is an Important Driver of PM Hepatic Glucose Uptake
Authors: Waterman Hannah , Moore Mary , Smith Marta , Farmer Ben , Yankey Kalisha , Kraft Guillaume , Scott Melanie
Published: May 2024

Glucose tolerance is significantly improved in response to consuming a second, identical meal later in the day. It is known that physiologic (portal vein) exposure to insulin in the morning primes the liver for increased hepatic glucose uptake and glycogen storage in the afternoon. Although this phenomenon has been observed in both healthy and diabetic individuals, it has not yet been established whether or not morning peripheral insulin delivery could bring about the same response. Thus, the aim of this study was to determine how the route of morning insulin delivery impacts the liver’s ability to extract and store glucose later in the day. To explore this aim, we delivered insulin into the portal vein (Po Ins) or a leg vein (Pe Ins) in the morning (AM) and subsequently challenged conscious dogs to a hyperinsulinemic-hyperglycemic (HIHG) clamp in the afternoon (PM). We then assessed the impact that each route of AM insulin delivery had on hepatic glucose uptake (HGU), non-HGU, and glycogen storage in the PM. The insulin infusion rates used in the Po Ins group were selected to mimic the rise in endogenous insulin secretion previously observed during a 4hr AM duodenal glucose infusion (2.1 mU/kg/min [0-30 min], 2.4 mU/kg/min [30-60 min], and 1.5 mU/kg/min [60-240 min]). In efforts to expose both groups to the same amount of insulin in the periphery while creating a difference at the liver, these rates were halved in the Pe Ins group. In the PM clamp, all groups received 4x basal insulin, 2x basal glycemia, and portal glucose infusion to simulate a second meal. During the 2.5hr PM clamp, the mean HGU was 1.8-fold higher in the Po Ins group vs. the Pe Ins group (HGU of 6.28±0.62 vs. 3.49±0.31 mg/kg/min; net AUC of 827±82 vs. 474±40 mg/kg/2.5hr, p<0.002), respectively, with no significant difference in non-HGU (net AUC of 819±118 mg/kg/2.5hr in Po Ins vs. 684±83 mg/kg/2.5hr in Pe Ins). Additionally, mean PM hepatic glycogen content was 47% larger in Po Ins vs. Pe Ins (23.6±1.1 vs. 12.5±1.5 mg/g liver, p<0.001), respectively. When compared to a group from an earlier study that received morning saline and a HIHG clamp in the afternoon (Sal Ctrl), there was no significant difference between Pe Ins and Sal Ctrl for any parameter measured. Therefore, physiologic hepatic insulin exposure in the morning is critical for increased hepatic glucose disposition and glycogen storage later in the day.

5T32DK007563 5R01DK131082-02.

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.
Estrogen Regulation of PAD2 and Citrullination in the Aging Female Heart
Authors: Shorthill Samantha , Yusifov Aykhan , Klinger Finley , Thornburg Joshua , Cherrington Brian , Woulfe Kathleen , Bruns Danielle
Published: May 2024

Advanced age is the primary risk factor for heart failure, an enormous public health burden. With aging, men tend to develop systolic dysfunction whereas women are predisposed to develop diastolic dysfunction. Despite these known phenotype differences, underlying molecular mechanisms of sex differences in cardiac aging are unknown. Citrullination, a post-translational modification catalyzed by the peptidylarginine deiminases (PAD) enzyme family, is positively regulated by the sex hormone estrogen (E2) suggesting a potential novel mechanism of age-related cardiac functional changes in women. We hypothesized that PAD expression and citrullination are sexually dimorphic with aging such that as E2 levels decline, so too does citrullination, thus contributing to diastolic dysfunction. We quantified expression of PAD2, the primary cardiac isoform, in female young reproductively competent adult (3 months) and aged (21 months) C57Bl6 mice. Consistent with clinical reports, in our model of aging, female mice developed diastolic dysfunction, with a prolonged linear phase relaxation (54.0 ± 1.7 msec, adult and 66.0 ± 3.3 msec aged, p<0.05). PAD2 expression decreased with age in the female heart, concomitant with decreases in myocardial protein citrullination. To identify potential mechanisms of differential citrullination by age, we performed cit-mass spectrometry. Adult female mice had higher overall citrullination patterns than aged females with enrichment of citrullinated proteins in metabolic, mitochondrial, and sarcomeric pathways. In reproductively competent adult females, cardiac PAD2 expression was higher during estrus compared to diestrus. To confirm direct regulation of PAD2 by E2, a cohort of adult mice underwent ovariectomy (OVX) with or without E2 replacement, provided orally in the water (0.5μM E2) for three weeks. Exogenous E2 supplementation post-OVX increased uterine weight and PAD2 expression, further confirming positive regulation by E2. Together, we suggest that hormonally regulated changes in PAD2 and citrullination with age contribute to sex-specific cardiac aging. Ongoing experiments will directly test the role of PAD2 in the heart by generation of a novel myocyte specific PAD2 deleted mouse across the female lifespan.

This abstract was made possible by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under 2P20GM103432. This work was supported by the National Institutes of Health [K01 AG058810 DRB, [K01 AG066845 KCW].

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.
Food Insecurity Impacts Diet Quality, Health-Promoting Activities, and Perceived Stress
Authors: Nagorny Katerina , Livshits Sarah , Bubis Sabrina , Chowdhury Ushima , Castillo Gabrielle , Valerius Alexis , Ifraimov Elliott
Published: May 2024

Food insecurity, defined as inadequate access to nutritious food, affects over two billion people globally. Poor nutrition and stress associated with food insecurity may negatively impact the performance of health-promoting activities. It may also increase stress levels through irregular eating patterns and concern over accessing suffcient food. However, the impact of food insecurity on engagement in health-promoting activities, stress, and dietary factors has yet to be studied extensively. This study aims to fill this gap by assessing the impact of food insecurity on health-promoting activities, perceived stress, and diet quality. It is hypothesized that food insecurity will negatively impact perceived stress levels and the frequency of engagement in health-promoting activities. It also hypothesized that those who engage in these activities more frequently will have better diet quality. An anonymous survey was administered to adults through various social media platforms. The survey contained demographic questions and seven validated scales: the Food Insecurity Experience Scale, Satisfaction, Alertness, Timing, Effciency, and Duration (SATED) Questionnaire, Health Promoting Activities Scale, Rosenberg Self Esteem Scale, Perceived Stress Scale, International Physical Activity Questionnaire, and the Food Mood Questionnaire. These scales measured food insecurity status, sleep quality, frequency of health-promoting activities and self-care, self-esteem, perceived stress levels, physical activity, and dietary habits, respectively. Data from 561 individuals were analyzed using Pearson’s Correlation Coeffcient in IBM SPSS Version 28.0. The results indicate that being unable to eat healthy and nutritious food was negatively associated with performing personal care tasks (r= -0.136, p< 0.01) and social activities (r= -0.146, p< 0.01). It was also found that having to skip a meal was positively associated with being upset when something happens unexpectedly (r= 0.218, p< 0.01) and feeling unable to control the important things in life (r= 0.242, p< 0.01). Further, performing personal care tasks was negatively associated with eating fast food (r= -0.120, p< 0.01) and positively associated with consuming dark green, leafy vegetables (r= 0.216, p< 0.01), whole grains (r= 0.195, p< 0.01), and fruit (r= 0.287, p< 0.01). Our results suggest that food insecurity can negatively impact mental well-being, diet quality, and health-promoting behaviors. Interventions aimed at improving food security, and therefore diet quality, may have benefits for improving overall health and well-being.

No funding was provided to conduct this research study.

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.
Temporal variations in immune and inflammatory markers following rodent juvenile traumatic brain injury
Authors: Smith Allie , Taylor Erin , Thompson Ashley , Dos Santos E Santos Christiano , Grayson Bernadette
Published: May 2024

Traumatic brain injury (TBI) is one of the leading causes of death and disability in the juvenile population. TBI is associated with elevations in inflammatory signaling. However, the temporal changes in immune and inflammatory markers following TBI, particularly in juvenile studies utilizing the Closed Head Injury Model of Engineered Rotational Acceleration (CHIMERA), have not been fully elucidated. The current study aimed to determine the time course of changes to immune cell expression throughout the first four days following juvenile TBI via the CHIMERA. Male Long Evans rats sustained either a TBI or a Sham TBI via the CHIMERA on post-natal day (PND) 30. Sham animals were euthanized at 3 hours (h) post-injury. TBI animals were euthanized at 0, 3, 6, 12, 24, or 96 h post-injury. Hippocampus samples were collected for use in QRT-PCR. The mRNA expression of cytokines IL1b and TNF-α was significantly elevated at 6 h, and C1q C chain (C1QC), a dendritic cell marker, was significantly elevated at 24 h. The mRNA expression of CD68, a marker for macrophages, was significantly elevated at 6, 24, and 96 h post-injury compared to Sham. CD3G, a marker for T cells, was significantly elevated at 6 hours post-injury. However, the mRNA expression of PTPRC, a marker for leukocytes, was not significantly altered throughout the time periods evaluated. To follow up on these studies, juvenile rats were injured and brains and blood were harvested 48 h post-injury comparing Sham and TBI. Peripheral blood lymphocytes were obtained and sorted by marker-specific antibodies. In the peripheral blood, there was a significantly higher number of CD3+ total T cells, CD3+/CD8 cytotoxic T cells, and CD3+/CD4+ helper T cells in the TBI group compared to the Sham, but CD45R+ total B cells and natural killer (NK) cells were not significantly different. Superior hemi-sected cortices were also used for immune cell extraction. There was a significantly lower number of NK cells and CD45R+ total B cells in the TBI group compared to the Sham, but CD45+ leukocytes and CD3+ total T cells were not significantly different. Further work is needed to understand the relationship between the reduction of specific cells in the brain with the elevation of cells in the peripheral blood.

This work is supported by T32HL105324 to AMS.

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.
Mechanical Circulatory Support Reduces Directly Recorded Renal Sympathetic Nerve Activity in an Ovine Model of Cardiogenic Shock
Authors: Warnakulasuriya Tania , George Bindu , Liver Nigel , Ramchandra Rohit
Published: May 2024

Cardiogenic shock (CS) following myocardial infarction carries a high mortality risk despite advancements in management. The use of mechanical circulatory support in CS has become an effective strategy to improve haemodynamics and prevent acute kidney injury. However, the mechanism of how kidney function improves is unclear. We hypothesised that mechanical support would inhibit renal sympathetic nerve activity (RSNA), mediating renal protection in CS. Experiments were conducted in two groups of anaesthetised female sheep. In one group, CS was induced (n=8) using injections of polystyrene microspheres into the left coronary artery under fluoroscopic guidance. After a 30-minute baseline period (post -embolisation), intravenous phenylephrine infusion at incremental doses was used to assess the baroreflex control of RSNA before pump insertion. When the pressures recovered to baseline values, the circulatory assist Impella pump was inserted into the left ventricle and run randomly at different levels (P0 min-P6 max) with two minutes at each pump level. The controls underwent the same protocol without embolisation (n=6). Coronary artery embolisation resulted in a drop in mean arterial pressure (MAP) of 21 ± 4 mmHg compared to baseline values (n=8). This was associated with a 67% increase in renal sympathetic nerve activity (RSNA) from 16 ± 5 to 21 ± 5 spikes/s (p=0.038; n=7). Circulatory support using Impella significantly increased MAP from 55 ± 4 mmHg to 68 ± 5 mmHg at pump level P6 (one-way ANOVA, p<0.001). Incremental pump support resulted in a significant decrease in RSNA (p<0.001). At pump level P6, RSNA was decreased by 25 ± 5 % compared to P0 (p<0.001). Baroreflex curves predicted a 2% reduction in RSNA at P6 equivalent pressures in CS, which was significantly less than that observed with circulatory support (p=0.006). In the control cohort with no CS, the changes in MAP and RSNA from P0 to P6 were qualitatively similar to the CS cohort. MAP increased from 84 ± 9 to 94 ± 8 mmHg (one-way ANOVA, p<0.001) and RSNA decreased by 13 ± 5 % at P6 (one-way ANOVA, p<0.001). The expected reduction in RSNA with baroreflex assessment at equivalent pressures to P6 was 5% in controls, which was not significantly different to what was observed (p=0.065). Our data indicate that the use of Impella pumps in CS reduces RSNA, which may mediate improvements in kidney function. Interestingly, the renal sympathoinhibition with the Impella pump is greater than that with vasoactive agents alone.

We gratefully acknowledge the granting support from Abiomed and the University of Auckland Faculty Research Development 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.
Antidiabetic activity of egg white protein hydrolysate in streptozotocin-induced diabetic rats
Authors: Thaeomor Atcharaporn , Srisawat Rungrudee
Published: May 2024

Egg white protein hydrolysate (EWH) has been reported to work as a cardiovascular protective agent. EWH exert antioxidant, vascular relaxing, anti-inflammatory properties and antihypertensive properties. This study aimed to assess the anti-diabetic and antihypertensive effect of the EWH in streptozotocin (STZ)-induced diabetic rats. Adult male Wistar rats were randomly divided into 2 main groups: normal and STZ-induced diabetes mellitus (DM) groups. Five subgroups of each main group were given distilled water, metformin (200 mg/kg), and EWH (300, 600, 1200 mg/kg) by oral gavage for 28 days (n=10 per each group). Fasting blood sugar level and OGTT were evaluated before and at the end of experiment. Each rat underwent monitoring of blood pressure using femoral artery. STZ-induced diabetic rats showed higher fasting blood glucose concentration and area under curve from OGTT than normal rats, which was significantly reduced by 600 mg/kg of EWH (p<0.05). STZ-induced diabetic rats showed higher mean arterial blood pressure than normal rats, which was significantly reduced by metformin (p<0.05). A decrease in hypertension in STZ-induced diabetic rats following EWH, but without significant difference, was observed. EWH may be useful in controlling the blood glucose level in diabetes mellitus and is therefore recommended for further studies.

This work was supported by Suranaree University of Technology (SUT), Thailand Science Research and Innovation (TSRI), and National Science Research and Innovation Fund. (NSRF) (FF1-111-65-12-30(08)).

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.
Inhibition of NF-κB Activation Improves Non-Nitric Oxide-Mediated Cutaneous Microvascular Function in Reproductive-Aged Healthy Women
Authors: Content Virginia , Williams Auni , Stachenfeld Nina , Alexander Lacy
Published: May 2024

PURPOSE: The human cutaneous circulation is used as an in vivo bioassay to examine mechanisms of systemic vascular function and dysfunction in health and disease. In cohorts of patients with accelerated cardiovascular disease risk, systemic interventions to investigate inflammatory mechanisms [e.g., oral salsalate; nuclear factor kappa-B (NF-κB) inhibitor] have been used to elucidate mechanisms underlying microvascular dysfunction. In healthy control subjects, inhibition of inflammatory mechanisms modestly reduces microvascular function. We hypothesize that inhibition of NF-κB activation may impair nitric oxide (NO)-mediated cutaneous microvascular function in reproductive-aged healthy women. METHODS: In a randomized, single-blind, placebo-controlled design, oral salsalate (1500mg/b.i.d./5 days) was used to assess the impact of systemic inflammation on cutaneous microvascular function. Two intradermal microdialysis fibers were placed into the ventral forearm skin of eleven healthy women [Mean (SEM): 34 (2) yrs]. Laser-Doppler flowmetry was used to measure cutaneous blood flow while increasing concentrations of acetylcholine (10−10 to 10−1 M; endothelium-dependent vasodilator) were perfused with a control (lactated Ringer’s) or a NO synthase inhibitor (15 mM NG-nitro-L-arginine methyl ester). Following the dose-response protocol, maximal cutaneous vasodilation was induced by increasing local skin temperature to 43°C and perfusing 28 mM sodium nitroprusside. Cutaneous vascular conductance (CVC) was calculated as the quotient of red blood cell flux over mean arterial pressure and normalized as a percentage of the site-specific maximum (%CVCmax). The NO-dependent contribution was calculated as the difference between the area under the dose-response curve (AUC) of the control and the NO synthase-inhibited sites. RESULTS: There was an overall main effect of salsalate treatment ( p < 0.001). Both the control and NO synthase-inhibited sites shifted upwards following salsalate treatment (Placebo - Control: 45.78 (8.81)% vs NO synthase inhibited: 33.62 (8.10)%; Salsalate - Control: 56.30 (8.48)% vs NO synthase inhibited: 41.57 (7.85)%; both p < 0.05). There was no change in the NO-dependent contribution between treatments (Placebo: 164.30 (35.40) AU vs Salsalate: 180.30 (51.17) AU; p=0.7028).CONCLUSION: Inhibition of NF-κB activation improved cutaneous microvascular function in reproductive-aged healthy women. This improvement was mediated via non-nitric oxide-dependent mechanisms.

Supported by NIH Grant R01 HL161000 (LMA) and Diversity Supplement R01 HL161000-02S2 (VGC).

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.
Mechanisms Involved in the Antihypertensive Effects of Arbequina Table Olives
Authors: Planas Joana M , Gómez-Contreras Aldo , Miró M. Lluïsa , Franco-Avila Talia , Juan M. Emília , Moretó Miquel
Published: May 2024

The Mediterranean Diet is associated with antihypertensive properties and prevention of cardiovascular disease. This dietary pattern includes the intake of Olea europaea L. derivatives such as extra virgin olive oil and table olives, characterized by a high content of bioactive compounds. Recently, it has been demonstrated that the supplementation of Arbequina table olives (AO) reduces blood pressure (BP) in spontaneously hypertensive rats (SHR). The aim of the present study was to elucidate the possible mechanisms involved in the antihypertensive effects of AO. Consequently, we have studied different plasmatic biomarkers (angiotensin II, Ang II; malondialdehyde, MDA; interleukin 6, IL6; tumor necrosis factor α, TNFα) and the fecal microbiota composition. Experiments were performed using male SHR from 14 to 21 weeks of age. SHR strain was divided into a control (SHR-c) and a treated group (SHR-o) that received water or AO (3.85 g/kg) by gavage, respectively. At the end of the experiment, BP was measured using a non-invasive automatic analyzer; Ang II, IL6, and TNFα were determined by Elisa, and MDA by spectrophotometric analysis. Fecal microbiota was analyzed by sequencing 16S rRNA gene using the Illumina MiSeq platform. Data were analyzed by t-Student or the Mann–Whitney U test, and statistical significance was considered when p<0.05. AO supplementation decreased systolic and diastolic BP by approximately 19 mmHg in SHR-o with respect to SHR-c. The decrement in BP was accompanied by a decrease in MDA (39%) and Ang II (32%) in SHR-o without changes in the concentrations of the proinflammatory cytokines IL6 and TNFα. Moreover, regular AO intake induced changes in the microbiota associated with the normalization of BP. Our results showed variations in relative abundance in genera such as Akkermansia, Sutterella, and Peptoniphilus, that were well correlated with the decrease in BP, MDA, and Ang II. In conclusion, OA supplementation reduced oxidative stress and Ang II associated with changes in the fecal microbiota that may explain the antihypertensive effect elicited by consumption of the fruit of Olea europaea L.

Supported by grants AGL2013-41188 & 2021SGR300. INSA Maria de Maeztu Unit of Excellence grant CEX2021-001234-M.

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.