bluuebunny/crossref_metadata_2025 huggingface dataset:
Sex-specific role for the clock protein PER1 in renal ET-1 regulation in salt-sensitive hypertension
Authors: Costello Hannah , Douma Lauren , Juffre Alexandria , Cheng Kit-Yan , Crislip G. Ryan , Zietara Adrian , Dissanayake Lashodya
Published: May 2024

Global knockout (KO) of the clock protein PERIOD1 (PER1) in male, but not female, C57BL/6J mice displayed both blunted blood pressure and urinary endothelin-1 (ET-1) rhythms. More recently, we showed that Dahl salt-sensitive (SS) Per1 KO male rats had exacerbated SS hypertension, alongside increased renal injury, renal ET-1 gene ( Edn1) expression, and ET-1 peptide expression from kidneys collected during the rat’s inactive period (2 PM). Additionally, we see increased long non-coding RNA EDN1-AS, which has been suggested to modulate ET-1 production. However, it is unknown whether PER1 regulates rhythms of ET-1 in SS rats and whether PER1 regulates ET-1 in a sex-dependent way. The study objective was to test the hypothesis that PER1 negatively regulates renal EDN1-AS and Edn1 to modulate ET-1 in a sex- and time-dependent manner. To test this hypothesis, kidneys were collected during rat’s active period (2 AM) from male and female SS Per1 KO and SS control rats on a normal salt (0.4% NaCl) or 3 weeks high salt (4% NaCl) diet ( N=5-6). Renal ET-1 protein levels were measured by ELISA and semi- and quantitative PCR was performed to quantify the levels of EDN1-AS and Edn1. Renal ET-1 levels were significantly higher at 2 AM than our previously reported data at 2 PM in both SS Per1 KO and control male rats ( p<0.0001). Renal ET-1 levels were significantly increased in male SS Per1 KO rats following a high salt diet ( p=0.0362) but not in females ( p=0.9522). This was also reflected in the Edn1 mRNA levels (male, p=0.0005; female, p=0.0814). EDN1-AS levels were also increased in males ( p=0.0123) but not in females. Interestingly, significant sex differences were seen in EDN1-AS levels, where EDN1-AS levels were higher in males than females following both low and high salt diets, suggesting a potential novel sex-dependent mechanism for ET-1 regulation. Together, these data suggest sex-specific action of PER1 in the regulation of ET-1 in a model of salt-sensitive hypertension. Future work aims to investigate blood pressure and renal injury in female SS Per1 KO rats and whether this apparent negative regulation of ET-1 by PER1 contributes to the SS hypertensive and renal injury phenotype seen in male SS Per1 KO rats.

This work was supported by the National Institutes of Health grants R35 HL135749 (to A.S.), R01 342 DK109570 (to M.G. and A.S.), and Department of Veteran Affairs grants I01 BX004024 (to A.S.).

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.
Acetyl-CoA Synthetase Short Chain Family Member-1 (ACSS1) acetylation status is an important regulator of adipose tissue thermogenic function
Authors: Chocron E. Sandra , Zhang David , Schell Joseph , Cruz Diego , Gius David , Gonzalez Porras Maria
Published: May 2024

Brown adipose tissue (BAT) is a crucial regulator of metabolism specialized in dissipating energy in the form of heat. Cold stimulated BAT uses glucose and free fatty acids for thermogenesis, impacting adiposity, glucose control, and insulin sensitivity. Furthermore, the ability of white adipocytes in white adipose tissue (WAT) to transition into thermogenic or beige adipocytes in response to cold exposure or specific pharmacological activators makes them a promising target for developing therapies to address obesity and other metabolic diseases. Sirtuin 3 (SIRT3), an NAD+- dependent deacetylase found within the mitochondria, controls BAT thermogenesis. Loss of SIRT3 in mice results in compromised BAT lipid metabolism, as well as impaired thermoregulation and mitochondrial respiration in BAT, without affecting UCP1 expression and/or function. Acetyl-CoA Synthetase Short Chain Family Member-1 (ACSS1) is an established SIRT3 deacetylation target that synthetizes acetyl-CoA using acetate that is central for fatty acid oxidation (FAO) and mitochondrial metabolism. To understand the function of ACSS1 acetylation role in BAT and WAT during thermogenesis response, we generated a ubiquitous acetylation mimic knock-in mouse by mutating lysine 635 to glutamine (K635Q), previously shown to alter ACSS1 enzymatic activity, which represents a constitutive ACSS1-K635-Ac rendering a protein with altered functionality. Our studies showed that these mice are intolerant to stimulation with b3 adrenergic receptor agonist CL316243 and died within 24 hours. These mice are not able to maintain body temperature and glucose homeostasis and also displayed dysregulated levels of the major lipid synthesis and oxidation pathways in BAT and inguinal subcutaneous WAT (iWAT). Importantly, the CL316243 intolerant phenotype was not observed in Acss1 knock out mice. This data suggests ACSS1-Ac status is an important regulator of adipose cells/tissue thermogenic function, and therefore is a potential therapeutic target for metabolic diseases. These results open a new roadmap to improve metabolic health through post- translational control of ACSS1.

Early Stage Investigator Award, Mays Cancer Center P30CA 054174.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
A novel antibody that neutralizes corticotropin-releasing factor attenuates the cardiovascular effects of chronic social defeat stress in mice
Authors: Scott Karen , Eikenberry Sophia , Johnson Dominique , Elsaafien Khalid , De Sa Jessica , Krumm Zachary , Golde Todd
Published: May 2024

According to the World Health Organization, cardiovascular disease (CVD) continues to be the leading cause of death worldwide. While a myriad of genetic and environmental factors influence the development of CVD, there are several lines of evidence suggesting that psychological stress contributes to health disparities in CVD observed amongst different populations. Our lab seeks to understand the effects of psychosocial stress on cardiovascular health using a model of chronic social defeat stress (CSDS) in mice. In this paradigm, male C57BL/6 mice undergo brief daily defeat sessions and are housed in the same cage as the larger, more aggressive CD1 defeater mouse, separated by a polycarbonate divider that allows for continuous visual, auditory, and olfactory contact while preventing physical contact. We have previously demonstrated that this paradigm causes robust and persistent elevations in blood pressure, indices of chronic inflammation, elevations in plasma corticosterone and cardiac and adrenal hypertrophy. Social defeat also leads to robust activation of corticotropin releasing factor (CRF) neurons within the paraventricular nucleus of the hypothalamus (PVN). In the present studies, we investigate whether we can alleviate some of the adverse effects of CSDS through targeting the HPA axis using CTRND05, a novel anti-CRF antibody. Adult male C57BL/6 mice were assigned to either CSDS or control (paired) housing. Following 14 days of CSDS or control housing, mice were treated with one injection of CTRND05 (25 mg/kg, i.p.) or vehicle (IgG), followed by 14 more days of CSDS or control housing. A booster administration of CTRND05 (12.5 mg/kg, i.p.) was given 7 days after the initial dose. Adrenal weights were significantly reduced in pair housed mice treated with CTRND05 compared to pair housed mice treated with IgG, and there was a trend towards a reduction in adrenal weight of CSDS mice treated with CTRND05 in comparison with CSDS mice treated with IgG. There was also a trend for reduced basal corticosterone in CSDS mice treated with CTRND05. Importantly, while IgG treatment had no effect on the systolic blood pressure (SBP) of CSDS mice, treatment with CTRND05 significantly lowered the SBP of CSDS mice when compared with pre-treatment. These data suggest that targeting CRF may serve as a therapeutic tactic for treatment of stress-related hypertension.

R35HL150750, R01HL136595.

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.
Left Ventricular Dilation Resulting from the Absence of Either Rgs2 or Rgs5 Is Associated with Increased Immune Cell Infiltration in the Myocardium
Authors: Dahlen Shelby , Nallapaneni Sanjana , Osei-Owusu Patrick
Published: May 2024

Sustained sympathoexcitation is a hallmark of heart failure, with equally sustained activation of downstream signaling pathways involving Gs- and Gi/o-coupled β-adrenergic receptors (βAR) stimulating cAMP production and PKA activation. A critical mechanism controlling G protein-mediated βAR signaling is the activity of regulator of G protein signaling (RGS) proteins, including members of the B/R4 subfamily, which accelerate the termination of Gq/11 and Gi/o protein signaling. Previous studies by us and others reported that moderation of Gi/o activity separately by RGS2 and RGS5 of the R4 subfamily is key to maintaining normal ventricular rhythm. The loss of one or both R4 RGS proteins also results in left ventricular (LV) dilation and reduced ejection fraction. Here, we tested the hypothesis that the LV structural remodeling is due to the disruption of the coordinated activity of RGS2 and 5 resulting in sensitization of βAR signaling. To test this hypothesis, we challenged wild type (WT), Rgs2 KO ,Rgs5 KO, and Rgs2/5 double knockout (dbKO) adult male mice with sub-chronic infusion of isoproterenol (ISO, 30 mg/kg/day, 3 days) via a peritoneal osmotic minipump implantation. Rgs2 KO and Rgs5 KO mice showed increased LV chamber size at baseline, which was unchanged by ISO administration. In saline-treated animals, the loss of Rgs2 increased Rgs5 mRNA expression, while Rgs5 absence increased Rgs4 mRNA expression. ISO infusion induced concentric cardiac hypertrophy in WT mice, as evidenced by increased heart weight/tibia length (HW/TL) ratio and cardiomyocyte cross sectional area. While ISO infusion increased interstitial fibrosis in midventricular tissue and HW/TL ratio in dbKO mice, it did not affect cardiomyocyte cross sectional area or exacerbate LV dilation, despite increased expression of the cardiac fetal gene Nppa as well as the sarcomeric protein α-actinin and Ca2+/calmodulin-dependent kinase II (CaMKII). Cardiact tissue from saline-treated Rgs2 KO and Rgs5 KO mice had markedly increased CD45+ cells vs WT, while tissue from Rgs5 KO mice showed increased CD68+ cells, as revealed by immunohistochemistry. Taken together, these results indicate that ventricular remodeling seen in Rgs2 KO, Rgs5 KO, and Rgs2/5 dbKO mice is insensitive to sustained βAR stimulation but may be due to increased cardiac resident immune cell population.

This work was supported by NIH R56 DK132859-01A1 and R01 HL139754, and Craig H. Neilsen Foundation Grant 382566 to Patrick Osei-Owusu.

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.
Time restricted feeding improves insulin resistance and reduces progressive proteinuria in young obese Dahl salt-sensitive rats prior to puberty
Authors: Mandal Sautan , Bhopatkar Anukool A. , Evans Lana , Johnson Alanis , Ekperikpe Ubong S. , Williams Jan M.
Published: May 2024

Prepubertal obesity (PPO) is now associated with early signs of renal disease. An improper eating behavior is one of the leading causes of PPO. Time restricted feeding (TRF) has been shown to be beneficial in obese patients without reducing body weight. However, the effects of TRF on renal injury during PPO have not been investigated. Therefore, the current study examined whether TRF reduces renal injury in obese Dahl salt-sensitive leptin receptor mutant (SSLepRmutant) rats before puberty. Four-week-old SS and SSLepRmutant rats were given either ad libitum access to food for 24 hrs (control) or 8 hrs during their active phase (TRF) for 4 weeks. Body weight and food intake were significantly higher in SSLepRmutant rats versus SS rats throughout the study, and TRF did not have an impact on both parameters. Fasting blood glucose levels were similar in all groups (≤120 mg/dL). Fasting plasma insulin levels were significantly higher in SSLepRmutant rats vs SS rats (5±1 vs. 1.0±0.1 ng/mL; p<0.05), and TRF reduced fasting plasma insulin by 70% in SSLepRmutant rats. Moreover, TRF markedly improved insulin resistance in SSLepRmutant rats. At the end of the study, we did not observe any differences in MAP (via carotid catheter) among the groups. Proteinuria was significantly higher in SSLepRmutant vs SS rats (361±32 vs. 17±4 mg/day; p<0.05), and TRF only reduced proteinuria in SSLepRmutant rats (144±19 mg/day; p<0.05). We observed a significant increase in GFR (via creatinine clearance) in SSLepRmutant rats compared to SS rats (0.71±0.08 vs. 0.39±0.07 mL/min/gkwt; p<0.05), and TRF normalized GFR in SSLepRmutant rats (0.37±0.07 mL/min/gkwt; p<0.05). Glomerular injury and renal fibrosis were markedly elevated in SSLepRmutant vs SS rats, and TRF improved these histological changes. Overall, these data suggest that TRF prevents the early progression of proteinuria by possibly reducing the insulin resistant effects on GFR during PPO.

NIDDK (DK109133) and AG (AG057842).

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.
Pathological effects of electronic cigarette exposure in mouse pregnancies
Authors: Clark Evan , Stapley B , Mattingly J , Kirkham Maddie , Chang A , Reynolds Paul , Arroyo Juan
Published: May 2024

Use of electronic Cigarettes (eCig) has increased worldwide in the last several years. Its use has been reported to be an effective smoking cessation tool and for being healthier than normal cigarette use. Although these reports exist, they lack supportive scientific evidence. Little is known about eCig effects during pregnancy. In the present study, we wanted to determine the effects of eCig exposure at two different important gestational points during mouse pregnancy in order to determine eCig exposure effects during pregnancy. C57/Bl6 mice were exposed to eCig via a nose-only delivery system (Scireq) for 4 days (from 14.5 gestational day (dGA) to 17.5 dGA) or for 6 days (from 12.5 dGA to 17.5 dGA). At the time of necropsy (18.5 dGA) placental and fetal weights were recorded. Maternal blood pressure was determined with a tail occlusion cuff (Kent Scientific) and proteinuria was detrained with the dip stick method. Markers for placental apoptosis were also determined. Treatment with eCig showed: 1) a significant decrease in placental weight and fetal weight (p<0.05) following 4 and 6 days of exposure, 2) higher systolic (p<0.02) and diastolic (p<0.02) blood pressure following 6 days of exposure, 3) increased proteinuria after 6 days of exposure, and 4) differential expression apoptosis markers in the placenta after 4 and 6 days of exposures. We conclude that detrimental effects of eCig coincides with the length of maternal exposure. We confirmed that 4 days of exposure resulted in metrics common to IUGR while 6 days of exposure more closely resembled PE/IUGR pathology. These results could be beneficial in understanding the long-term effects of eCig exposure and the development of placental diseases.

This work was supported by the National Institutes of Health grant number 1R15HD108743.

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.
Proteomic Analysis of Prehypertensive and Hypertensive Patients: A Novel Role of Actin Cytoskeleton in Disease Progression
Authors: Al Ashmar Sarah , Anlar Gulsen Guliz , Krzyslak Hubert , Djouhri Laiche , Kamareddine Layla , Pedersen Shona , Zeidan Asad
Published: May 2024

Background: Hypertension is a pervasive and widespread health condition that poses a significant risk factor for cardiovascular disease, which includes conditions such as heart attack, stroke, and heart failure. Despite its widespread occurrence, the exact cause of hypertension remains unknown, and the mechanisms underlying the progression from prehypertension to hypertension require further investigation. Methods: To uncover potential biomarkers related to disease development, proteomic profiling using SOMAscan proteomic platform was conducted on Qatari individuals with prehypertension and hypertension. In this study, proteomic data collected from the Qatar Biobank were analyzed to compare participants with prehypertension, hypertension, and normal blood pressure. Statistical analysis was performed to identify altered protein expression between the study groups and to elucidate the biological pathways contributing to this disease. Results: The results revealed a cluster of proteins, including the SRC family, CAMK2B and CAMK2D, TEC, GSK3, VAV, and RAC, that were markedly upregulated in patients with hypertension compared to those with prehypertension (fold change ≥ 1.6 or ≤ -1.6, area under the curve ≥ 0.8, and q-value < 0.05). Pathway analysis showed that the majority of these proteins play a role in actin cytoskeleton remodeling, a crucial pathological event involved in hypertension progression. Conclusion: Actin cytoskeleton reorganization affects various biological processes that contribute to the maintenance of blood pressure, including vascular tone, endothelial function, cellular signaling, inflammation, fibrosis, and mechanosensing. Therefore, the findings of this study suggest a potential novel role of actin cytoskeleton-related proteins in the progression from prehypertension to hypertension. The present study sheds light on the underlying pathological mechanisms involved in hypertension and could pave the way for new diagnostic and therapeutic approaches for the treatment of this disease.

This study was made possible through the support of Qatar University.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Sex Differences in Ammoniagenesis in Obese, Diabetic, ZSF1 Rats
Authors: Schwindt Seth , McFarlin Brandon , Liu Katie , Perez Andrea , Ralph Donna , McDonough Alicia
Published: May 2024

Diabetic ketoacidosis develops when insulin is insuffcient to clear blood sugar into cells for energy, then the liver breaks down fat for fuel with production of ketoacids. Lower pH activates proximal tubule PEPCK expression to replenish bicarbonate and excrete acid via NHE3 as ammonia, known as, “ammoniagenesis.” Baseline female (F) rodents exhibit greater ammoniagenesis and less NHE3 activity than males (M). We examined ammoniagenesis in male (M) and female (F) ZSF1 rats, a model of obesity and diabetic kidney disease. ZSF1 rats are born lean (L) or obese (O). OM display hyperglycemia and glucosuria at 10 wk, not yet evident in OF at 18 wk. We tested three hypotheses in ZSF1 rats (n=4-6/group): 1) ammoniagenesis rate is greater in OM and OF than LM and LF, 2) LF exhibit a higher rate of ammoniagenesis than OF, and 3) the blood glucose lowering SGLT2 inhibitor empagliflozin (SGLT2i) reduces ammoniagenesis in OM. Ammoniagenesis was measured as ammonia/24 hr/tibia length because OM and OF weigh 50% more than LM and LF. Abundance of PEPCK and NHE3 was assessed by semiquantitative immunoblots. Titratable acidity (TA) was measured as classically defined. In OM, ammoniagenesis was 6X greater (P< 0.0001), and TA elevated (P=0.0003) versus LM. Ammoniagenesis was not different in OF vs LF (P=0.99). Ammoniagenesis was only 2X greater in OM vs OF (P=0.001) indicative of higher baseline ammoniagenesis in F vs M. PEPCK abundance was 2.8X greater in both OM and OF vs LM and LF (P< 0.001), and NHE3 abundance was lower by 35 and 20%, respectively, in OM and OF vs LM and LF (P< 0.003). Oral SGLT2i treatment (10 mg/d, n=5-6/group, 6 wks starting at 20 wk old) vs vehicle lowered plasma glucose 35%, doubled urine glucose excretion, but did not significantly alter ammoniagenesis, PEPCK or NHE3 abundance (but tended to reduce urine TA). These findings demonstrate that at 16 weeks, OM exhibit highly elevated ammoniagenesis and TA along with hyperglycemia. In contrast, OF do not exhibit hyperglycemia nor elevated ammoniagenesis, illustrating a resistance to diabetic ketoacidosis at 16 wk, despite obesity, higher TA (P= 0.003), higher PEPCK and lower NHE3. In 20 wk old OM ZSF1, SGLT2i treatment does not reverse ammoniagenesis despite lowering plasma glucose for 6 weeks.

R01 DK083785, R25DK113659, NIH Step Up U24 DK115255,.

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.
Endothelin A Receptor Activation on Vascular Smooth Muscle Cells Mediates Visceral Adipose Tissue Inflammation in an Obese Mouse Model
Authors: Newberry Madison , Mills Megumi , Murphy Hayley , Michael Joshua , Wilson Natalie , Taylor Erin , Speed Joshua
Published: May 2024

Obesity causes a pro-inflammatory shift in visceral adipose tissue immune cells that is thought to promote adipocyte dysfunction and obesity pathophysiology. Endothelin-1 (ET-1) is a small peptide produced mostly by endothelial cells that causes inflammation in diseases including a number of nephropathies and autoimmune diseases. ET-1 is increased in obese patients and in rodent models of obesity. Our lab has demonstrated that mice fed high fat diet (HFD) have an increase in visceral adipose tissue CD4+ and CD8+ T cells and a reduction in anti-inflammatory eosinophils that is attenuated by treatment with an ET-1 type A receptor (ETAR) antagonist; however, the mechanisms by which ET-1 leads to inflammation remain unknown. The ETAR is highly abundant on vascular smooth muscle cells (VSMC), where activation causes a significant increase in pro-inflammatory interleukin-6 production. We hypothesized that elevated ET-1 production in visceral adipose causes a pro-inflammatory shift in tissue immune cells by activating VSMC ETAR. To test this hypothesis, 8-week-old floxed control and vascular smooth muscle cell-specific ETA knockout (SMAKO) mice were placed on either normal (n=5 and 3 for control and SMAKO respectively) or high-fat diet (n=6 and 4 for control and SMAKO respectively) for 12 weeks. Tissue immune cells were quantified by flow cytometry. As expected, HFD fed mice had significantly increased body weight, lean mass, and fat mass, as measured by EchoMRI, compared to NMD fed mice; however, there was no detectable difference due to genotype. There was a significant increase in CD4+ T cells (control NMD: 2.45 ± 0.28 vs. control HFD: 4.37 ± 0.80 % of CD45+ cells; SMAKO NMD: 0.94 ± 0.52 vs. SMAKO HFD: 2.24 ± 0.40 % of CD45+ cells; pint=0.63, pdiet=0.02*, pgenotype=0.01*) and CD8+ T cells (control NMD: 0.49 ± 0.10 vs. control HFD: 2.02 ± 0.59 % of CD45+ cells; SMAKO NMD: 0.12 ± 0.07 vs. SMAKO HFD: 0.52 ± 0.07 % of CD45+ cells; pint=0.20, pdiet=0.04*, pgenotype=0.04*) that was significantly attenuated in SMAKO mice. In addition, HFD fed control mice had a greater reduction in eosinophils compared to NMD floxed control. The reduction in eosinophils was attenuated in SMAKO (control NMD: 5.28 ± 2.01 vs. control HFD: 1.28 ± 0.07 % of CD45+ cells; SMAKO NMD: 5.92 ± 0.94 vs. SMAKO HFD: 4.49 ± 1.60 % of CD45+ cells; pint=0.42, pdiet=0.09, pgenotype=0.23). These data suggest that ET-1-induced adipose tissue inflammation in obese mice occurs via activation of ETAR on VSMCs.

R01DK124437, P30GM149404, and T32HL105324.

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 Protective Role of Resilience on Cardiovascular Health in Young Adults Exposed to Adverse Childhood Experiences
Authors: Tunon Enrique , Matheson Chloe , Simovic Tijana , Colon Marisa , Krieger Benjamin , Thode Christopher , Garten Ryan
Published: May 2024

Background: Adverse childhood experiences (ACEs) are strong emotional or physical stressors that occur during sensitive developmental periods and are associated with reduced cardiovascular health (CVH). Resilience, or the psychological capacity of individuals to cope with adversity, has been recently shown to have a positive influence on CVH. Despite the dose-dependent detrimental impact of ACEs on CVH, it is unknown whether resilience exerts a protective cardiovascular effect against early stress. Thus, the purpose of this study was to investigate the impact that resilience may have on CVH in young adults who experienced ACEs. Methods: Eighteen young and apparently healthy adults (22±3 yo) with a history of severe ACE exposure (≥4) participated in this study and provided self-reported data about resilience. CVH was assessed non-invasively through transcutaneous arterial tonometry to evaluate arterial stiffness (pulse-wave velocity, PWV), myocardial oxygen demand (Systolic Pressure Time Index, SPTI), myocardial oxygen supply (Diastolic Pressure Time Index, DPTI) and myocardial perfusion (Subendocardial Viability Ratio, SEVR). Circulating biomarkers related to CVH were also evaluated (high-sensitive C-reactive protein, hsCRP). Results: Eleven participants reported high resilience (HR: resilience score≥95), while seven reported low resilience (LR: resilience score<95). Young adults with high resilience presented with a significantly lower myocardial oxygen demand (SPTI; HR: 1866±111 vs. LR: 2227±117mmHg·s/min, p=0.047) and higher myocardial perfusion (SEVR; HR: 168±13 vs.LR: 127 ±9% , p=0.034) than those with low resilience and a positive association between SEVR and resilience was identified ( r=0.492; p=0.045). No differences in myocardial oxygen supply ( p=0.225) or arterial stiffness ( p=0.614) were observed between groups. However, circulating hsCRP was also significantly lower in the HR group than the LR (0.89±0.3 vs. 2.96±1 mg/dL, p=0.041) and negatively associated with resilience ( r=-0.511; p=0.051). Conclusions: Our data suggests that, among young and apparently healthy adults exposed to childhood adversity, those who are psychologically more resilient exhibit higher myocardial perfusion and overall better CVH than those less resilient despite a history of severe ACEs. These findings suggest that resilience may protect, at least partially, against the early impact of ACEs on CVH. Future studies are thus warranted to further explore the relationship between resilience and CVH.

Supported in part by the Child Health Research Institute at VCU.

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.
Effects of N-Acetyl-Carnosine Treatment on Aging and Carbonyl Stress
Authors: Miranda Edwin , Shahtout Justin , Watanabe Shinya , Werbner Ben , Neiswanger Grace , Milam Norah , Drummond Micah
Published: May 2024

By 2050 the number of individuals over the age of 80y will triple to reach 426 million and the rate of age-related comorbidities has also increased precipitously as our global population has continued to age. Currently, there is no clinically approved treatment for age-related functional decline creating demand for the development of such treatments. Our lab previously demonstrated that carbonyl stress is exacerbated in muscles during a hindlimb unloading (HU) model of inactivity. Importantly, the accumulation of proteins modified by the reactive lipid carbonyl 4HNE, as well as muscle dysfunction and atrophy, were attenuated in HU mice treated with the carbonyl-scavenging dipeptide N-acetyl-carnosine (N-Ac-Carn). Therefore, we hypothesized that N-Ac-Carn could prevent carbonyl stress in aging muscles and other tissues. 17-month-old male and female C57Bl6J mice from the NIA colony were treated for 6-months with 80 mM N-Ac-Carn or normal (CON) water. Before and after the 6-month intervention we assessed several markers of health including glucose tolerance, kidney, muscle, bone, and cognitive function. N-Ac-Carn preserved ex vivo muscle force production in soleus ( p=0.0015) and EDL ( p=0.0008) muscles from female but not male mice. N-Ac-Carn treated mice also possessed superior bone volume compared to CON ( p=0.0046). Following terminal tissue collection, we also assessed muscles for carbonyl stress by probing for proteins modified by total carbonyls, 4HNE, MDA, and methylglyoxal. N-Ac-Carn did not attenuate 4HNE, MDA, or total carbonyls in gastrocnemius. However, N-Ac-Carn showed strong trends for attenuating 4HNE burden in both soleus and EDL muscles. N-Ac-Carn is an endogenously produced dipeptide that is safe for human consumption and affordable making it a promising therapeutic strategy for the mitigation of age-related functional decline.

AG074535-02S2.

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.
Remodeling of Ventricular Catecholaminergic Axons Following Chronic Intermittent Hypoxia in Mice
Authors: Bizanti Ariege , Zhang Yuanyuan , Bendowski Kohlton T. , Madas Jazune , Toledo Zulema , Qu Lucas , Chen Jin
Published: May 2024

Chronic intermittent hypoxia (CIH) is a widely employed model for sleep apnea. The imbalance of autonomic control may contribute to CIH-induced cardiovascular diseases. Previously, we demonstrated that CIH increases sympathetic innervation of the atria. In this study, we determined whether CIH remodels peripheral cardiac tyrosine hydroxylase (TH, a marker for sympathetic efferent axons) innervation in the whole ventricles. The two challenges here were: 1) labeling the entire TH-IR axon innervation in the full thickness (~500 μm) of whole flat-mount ventricles. 2) Quantifying the topographical distribution of TH-IR axons through the thick ventricular walls at the single axon/varicosity scale. In this study, C57BL/6J mice (male, 2 months old, n=7/group) were exposed to room air (RA, 21% O2) or CIH (alternating between 21% and 5.7% O2 every 6 minutes for 10 hours/day) for 8-10 weeks. We prepared flat-mounts of the whole ventricles and septum and processed them with immunohistochemical labeling for TH. Using the Zeiss M2 Imager, confocal microscope, Zeiss Arivis Vision 4D, and Neurolucida system, we traced and digitized the TH-IR axons. We found that: 1) In RA and CIH mice, several large TH-immunoreactive (TH-IR) bundles from the base area entered the ventricles and septum. These large bundles branched into numerous smaller bundles as they traveled downward toward the apex and finally developed into fine varicose axons and terminals in the epicardial and myocardial layers. 2) Using Vision 4D, we were able to accurately detect, trace, and digitize all TH-IR axons in the ventricle walls with high accuracy. 3) CIH increased overall TH-IR axon density and network complexity of the whole ventricles and septum. 3) Abnormal CIH TH-IR axon terminal structures were frequently seen. 4) We geometrically and precisely registered the tracing data into a scaffold map for presentation and comparison in 3D. Altogether, CIH increased sympathetic innervation of the heart which may contribute to the augmented sympathetic drive. Our success in mapping data in the 3D heart scaffold will establish a heart-brain connectome/atlas.

Supported by NIH 1 U01 NS113867-01 NIH R15 1R15HL137143-01A1, 2R01HL137832-05 and Carl Zeiss.

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 role of CCN1 in kidney-brain crosstalk
Authors: Peti-Peterdi Anna , Peresztegi Lena , Becerra Calderon Alejandra , Izuhara Audrey , Deepak Sachin , Gyarmati Georgina , Peti-Peterdi Janos
Published: May 2024

Cognitive impairment and dementia are major global health problems of the aging human population. It is estimated that about 55 million people were living with dementia in 2019 and this number is expected to triple by 2050. Dementia can result from abnormal structure and function of brain blood vessels that may develop in a variety of conditions including chronic kidney disease (CKD). Recent studies from our laboratory suggest that in addition to controlling blood volume and blood pressure (renin), and blood cell count (erythropoietin), the kidney produces novel systemic angiogenic hormones to maintain blood vessels, such as the matricellular protein Cellular Communication Network factor 1 (CCN1). These hormones are then released to the blood and may act as new molecular mechanisms of kidney-brain crosstalk. We hypothesized that kidney-derived CCN1 helps to preserve the normal structure and function of blood vessels throughout the body, including a healthy blood-brain barrier (BBB). We further hypothesized that reduced plasma CCN1 caused by diminished renal production of CCN1 due to kidney disease plays a major role in the development of brain vascular dysfunction, and therefore in the pathogenesis and progression of dementia and cognitive impairment. Intravital multiphoton (MPM) imaging of the intact mouse brain in control or after 5/6 nephrectomy (5/6 Nx), a well-established mouse model of chronic kidney disease (CKD) was used to measure changes in BBB permeability with or without chronic CCN1 treatment. Kidney and BBB structure/function phenotyping was performed using CCN1 ELISA assay, the Medibeacon transdermal GFR measurement system, tissue harvest, and immunohistochemistry. Compared to control, 5/6 Nx mice had reduced plasma CCN1 levels, reduced GFR, but no difference in systolic blood pressure. MPM imaging showed increased fluorescence intensity of mid-size plasma proteins (A680 conjugated Albumin 70 kDa) compared to high molecular weight markers (A488 conjugated Dextran 500 kDa) in brain interstitium in 5/6 Nx compared to control. In addition, the density of cell-to-cell junctions in brain endothelial cells were 20% reduced in CKD compared to control healthy mice. In brain endothelial cells cultured in vitro, CCN1 treatment had protective effects on cell proliferation, motility and angiogenesis as confirmed by scratch and tube formation assays. In summary, this study identified new mechanisms of kidney-brain crosstalk, and helped to improve our mechanistic understanding of cerebrovascular pathology in CKD.

DK123564, DK064324, DK135290.

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.
Acute Hypoxia Following Disuse Atrophy in Aged Mice Enhances Cellular Remodeling and Whole-body Strength During Early Recovery
Authors: J. Fennel Zachary , Bourrant Paul-Emile , M. Yee Elena , Castro Robert , Kurian Anu , Drummond Micah
Published: May 2024

Age-related impairments in muscle recovery following disuse atrophy are associated with altered macrophage metabolism and blunted inflammatory function. HIF-1α is a key regulator of macrophage metabolism and inflammatory function. Therefore, we investigated the effects of acute hypoxia on muscle recovery following disuse in aging. We hypothesized that transient hypoxic exposure following disuse in aged mice would enhance macrophage metabolism and inflammatory status, resulting in improved muscle cellular remodeling and recovery. Accordingly, old (~20 months) and young adult male mice (~4 months) were exposed to acute (24 hours) normobaric hypoxia (8% O2) immediately following 14-days hindlimb unloading. We characterized muscle phenotype and function during early recovery (4- and 7-days) with and without hypoxia exposure. We found that acute hypoxia stimulated the expression of inflammatory (TNF-α, VEGF p<0.01) and glycolytic transcripts (PFK-1 p<0.05), LDH, PDH p=0.08) downstream of HIF-1α in aged skeletal muscle under basal conditions. Following disuse atrophy, transient hypoxic exposure enhanced macrophage inflammatory function, indicated by increased phagocytosis capacity (p<0.01), and promoted early skeletal muscle cellular remodeling events, including enhanced muscle satellite cell content (p<0.05). Furthermore, these effects facilitated the recovery of whole-body strength in aged mice indicated by a return to baseline values (p>0.05). The results of this investigation suggest that hypoxic exposure following disuse atrophy promoted inflammatory macrophage function, muscle cellular remodeling, and enhanced early recovery in aged mice. These findings elucidate the potential benefits of hypoxia in manipulating macrophage function to ameliorate age-related deficits in muscle recovery following disuse atrophy.

This research was supported by R01AG076075 (MJD) and the National Institutes of Health Ruth L. Kirschstein National Research Service Award 5T32DK091317 from the National Institute of Diabetes and Digestive and Kidney Diseases.

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

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

British Heart Foundation.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Recruitment of T-cells to the lung using an ex vivo co-culture paradigm
Authors: Ehrlich Alexis , Tobet Stuart
Published: May 2024

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

Anschutz Foundation Pandemic Preparedness Grant.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Activin A Contribution to Diabetic Kidney Disease Injury and Effects of Activin A Antagonism In-Vitro
Authors: Learmonth Maya , Skaff Caroline , Snow Zachary K. , Bian Xiaohui , Hickson LaTonya
Published: May 2024

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

NIH 5TL1TR002380-07, AG076537, DK123492, DK109134.

This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.