bluuebunny/crossref_metadata_2025_split huggingface dataset:
Galectin 3 secretion in pulmonary arterial hypertension
Authors: Haigh Stephen , Bordan Zsuzsanna , Sellers Hunter , Brown Zach , Meadows Mary Louise , Barman Scott , Fulton David 
Published: May 2023

Pulmonary arterial hypertension (PAH) is a complex and fatal disorder characterized by an unrelenting increase in pulmonary arterial pressure. Excessive proliferation of pulmonary artery smooth muscle cells (PASMC) leads to increased vascular resistance and eventually right ventricular failure and death. Our lab has hypothesized that circulating Galectin-3 (Gal-3), a readily secreted b-galactoside-binding lectin protein, previously investigated as a biomarker of PAH, has a key role in the pathology of PAH. Co-culture experiments as well as recombinant protein supplementation show that soluble GAL-3 is biologically active and induces SMC growth and proliferation(P<.05). Inversely, inhibition of GAL-3 using blocking antibodies prevents this SMC proliferation. (p<.05) To test our hypothesis in-vivo we injected GAL-3 KO mice with a liver specific AAV overexpressing GAL-3 or GFP (control) and exposed them to sugen/hypoxia to induce PAH. Surprisingly our initial findings indicate no protection with liver GAL-3 overexpression compared to GFP transduced mice. Contrary to our hypothesis, while liver overexpression of GAL-3 was robustly increased, there was no evidence of GAL3 in the lungs or plasma of GAL3KO mice indicating it may not be robustly secreted from the hepatocyte, unlike what was observed in other cell types. This lack of circulating Gal-3 generated by liver overexpression revealed a knowledge gap in the mechanism of Gal-3 secretion into the circulation. To address this we have generated at a number of mutant forms of GAL3 that alter motifs proposed to be relevant to Gal-3 secretion. R186S prevents binding to the all but 1 of the 176 of GAL-3 binding glycans however this appears to have no impact on its uptake in GAL-3 KO cells. Similarly, L131A/L203A GAL-3 which prevents the oligomerization of GAL-3 by preventing interaction of the carbohydrate recognition domain with its n terminal binding domain (responsible for oligomerization) also maintains its ability to interact with these cells. These changes did not interfere with its secretion into the media. However, these interactions do appear to be altered somewhat, when a cell surface biotinylation assay is performed there is significantly less R185S on the cell surface compared to WT GAL-3. Our findings suggest that ECs and SMCs can secrete GAL-3 and exert pathological actions such as increasing proliferation in vitro. Our blocking antibody further suggests that this secreted GAL-3 is capable of regulating SMC proliferation and provides evidence for possible treatment of PAH. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Effect of ECM and mechanical strain on vascular cell plasticity
Authors: Brady Travis , Santhanam Lakshmi , Gerecht Sharon 
Published: May 2023

Introduction: Depending on surrounding cell types, substrate mechanics, and chemical agonists, vascular smooth muscle cells (VSMCs) alternate between a contractile and synthetic phenotype. While endothelial cells (ECs) do not modulate their phenotype in this way, their behavior is highly dependent on location within the body. These variations are part of healthy vascular function, but improper phenotype has been implicated in cardiovascular disease. Atherosclerotic lesions, for example, have been found to be high in dedifferentiated, synthetic VSMCs as well as endothelial cells that have undergone endothelial to mesenchymal transition (EndMT). The overall goal of this project is to understand the effect of cross-talk between ECM and mechanical strain on vascular cell plasticity during aging. Materials and Methods: Mouse aortic smooth muscle cells (maSMCs) were isolated from C57Bl6 mice at less than 3 months (young), 6 to 10 months of age (middle-aged; MA), or greater than 15 months of age (old). Cells were then seeded onto dye-quenched (DQ) collagen type I (Col-I) substrate and measured for gain of fluorescent signal over 3 days. Human aortic endothelial cells (HAECs) were seeded onto glass cover slips or fibronectin coated PDMS chambers. Cells were further treated with or without TGF-β2 with daily media changes over 3 days. IF images were captured with a Leica Confocal microscope and quantification was performed using ImageJ. Results: ECs cultured on glass or treated with TGF-β2 show increased expression of SM22α and decreased expression of VECAD. Physiological strain (10%) did not cause changes in expression relative to static (0%). Mouse aortic SMCs isolated from older mice had significantly decreased rates of Col-I cleavage. Conclusions: maSMCs from older mice have lower Col-I turnover than their younger counterparts. This is consistent with bulk tissue behavior, as it is well known that relative collagen levels increase in the elastic vasculature as we age. HAECs on stiff substrates are more likely to show signs of EndMT – consistent with other studies. The addition of agonists such as TGF-β2 can reproduce this behavior in cells cultured on soft substrates. NASEM Ford Foundation Pre-Doctoral Fellowship and NHBLI grant R01HL148112 01 (L.S.) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Deletion of myostatin alters obesity-induced estrogen metabolism in skeletal muscle
Authors: Rosewater Cody , Guilfoyle-Speese Andrew , Padget Caleb , Mintz James , Brown Zach , Fulton David , Stepp David 
Published: May 2023

Objective: Obesity alters sex hormone balance in males, resulting in low testosterone and altered metabolism of estrogen, independent risk factors for cardiometabolic dysfunction. The basis of these alterations and how they are impacted by factors that improve cardiometabolic outcomes in obesity are unknown. Methods: Control and obese mice ( db/db) with or without deletion of myostatin to induce hypermuscularity were used. Mice were analyzed for plasma sex hormones via mass-spectrometry with or without 10mg/kg/day fadrazole to inhibit aromatase. Quantitative PCR was used to measure aromatase along with cytochrome P450 enzymes involved in estrogen metabolism in the liver, skeletal muscle, and visceral adipose tissue. HEK293a cells were treated with myostatin in vitro and enzyme levels assessed. Results: Obesity decreased plasma testosterone 30% and increased estrogen 20% with no change in gonadal weight. Deletion of myostatin increased muscle mass >30% and resulted in a reduction in estrogen levels without a parallel increase in androgens in obese mice. Inhibition of aromatase restores estrogen levels indicating the excess estrogen in obesity is derived from testosterone conversion. Since estrogen was lowered without increasing testosterone and estrogen metabolism must be increased. Aromatase was increased in obesity but unaffected by changes in muscle mass. CYP1B1, an enzyme that converts estradiol to hydroxy estrogens, showed 2.5 fold expression in obese skeletal muscle, which is improved in the absence of myostatin, with no change in other P450s involved in estrogen metabolism. Moreover, changes in P450 enzymes in liver or fat were either absent or changed directionally opposite to observed hormone changes. In HEK cells, treatment with myostatin recapitulated changes in CYP1B1 expression seen in vitro, suggesting a direct link between the myokine and sex hormone metabolism by skeletal muscle. Conclusion: In summary, obesity causes a shift in sex hormone levels to estrogen production, which is improved by myostatin deletion, without restoration of androgens. A potential mechanism responsible could be altered estrogen catabolism, leading to decreased estrogen levels without the restoration of androgen levels. Together, these data suggest CYP1B1 drives the conversion of estrogen to hydroxestrogens, which are known pro-oxidant and pro-lipidemic influences that may contribute to cardiometabolic disease. Whether targeting CYP1B1 improves cardiometabolic function in obesity remains to be determined. D.W. Stepp and D.J. Fulton are supported by NIH 1R01HL147159 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
The Impact of a Vegan Diet on Cardiovascular Disease Risk in Men and Women Through the Gut Microbiome
Authors: Lee Amanda , Uno Jennifer 
Published: May 2023

Studies highlight many benefits of a vegan diet on the composition of the gut microbiome, however little is known how and if these changes contribute to heart health. Trimethylamine (TMA) is a metabolic product produced from the breakdown of choline and L-Carnitine both found abundantly in red meat. TMA is converted to toxic trimethylamine N-oxide (TMAO) in the liver via flavin monooxygense 3 (FMO3). The objective of this study was to examine if vegan diets impact TMA levels thus supporting cardiovascular health. We hypothesize that a vegan diet will foster bacterial diversity that favors decreased TMA/TMAO levels. Zebrafish were initially placed on antibiotics to clear their microbiome, following treatment, fish were fed a control, high fat (HF), or vegan diet for 3 weeks. Fish were sacrificed and intestinal, liver and heart tissue were harvested for analysis. Surprisingly, we observed the most significant increase in bacterial abundance in the HF diets relative to the vegan and control diets (n= 5-6, p< 0.05). Interestingly, when separated by sex, the highest change in bacterial abundance was seen in female fish on a HF diet. We next examined mRNA levels of FMO3. We saw the greatest increase in FMO3 levels in female fish on a HF diet, which corresponds to higher bacterial abundance (n= 5-6, p< 0.05). FMO3 levels were also increased for fish on a HF diet relative to the control diet with no significant differences between male and female fish. These results indicate that vegan diets may alter male and female bacterial composition differently and the impacts of these differences on CV health remain unknown. Funding thus far has come from Elon University. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Thermal and Cardiovascular Responses During a Very Hot and Dry Heatwave Simulation in Young and Older Adults
Authors: Foster Josh , McKenna Zachary , Sarma Satyam , Macnamara James , Belval Luke , Watso Joseph , Atkins Whitley , Orth Bonnie , Johnson Elias , Benning Mayah , Jarrard Caitlin , Crandall Craig 
Published: May 2023

Heatwaves cause disproportionately high mortality rates in those aged ≥ 65 years. While age differences in the cardiovascular responses to heat stress have been investigated, previous studies used a water-perfused suit to elicit heat stress. Therefore, how aging affects the cardiovascular responses to prolonged environmental heat stress is not fully understood. Purpose: We tested the hypothesis that 3 hours of exposure to a very hot and dry heat wave condition would increase core temperature and left ventricular systolic contractility (s’) to a greater extent in older, compared with younger adults. Methods: Healthy young (n = 13, 6F/7M, 29±4 years, 1.82±0.13 m-2) and older (n = 19, 10F/9M, 70±4 years, 1.85±0.18 m-2) adults were exposed to 47°C, 15% humidity) for 3-hours, interspersed with seven 5-minute bouts of physical activity at 3 METS to replicate heat generation associated with activities of daily living. Core temperature, brachial blood pressure and heart rate were monitored continuously during heating. Echocardiograms were obtained at baseline (in a thermoneutral environment) and at three hours into heat stress (i.e., post-heat wave) to assess s’. Drinking water was provided throughout the protocol to minimize dehydration. The magnitude of the change in each variable from baseline to post-heatwave between age groups was compared using independent samples t-tests. The association between the change in core temperature and the change in s’ was assessed with linear regression. Results: From baseline to 3-hour heatwave exposure, there was a greater increase in core temperature (Δ1.36±0.28 vs Δ0.74±0.28 °C, p < 0.0001) and s’ (Δ3.3±2.2 vs Δ1.6±1.8 cm/s, p = 0.011) in older, compared with younger subjects, respectively. However, the magnitude of the change in core temperature was not associated with the increase in s’ in older of young subjects (R2 = 0.065 and 0.120, respectively). The older subjects showed a greater decrease in mean arterial pressure compared with younger subjects (-14±10 vs -4±7 mmHg, p = 0.004). Heart rate increased similarly in older and young subjects (27±13 vs 27±12 b/min, p = 0.412). Conclusions: Our findings suggest that an index of left ventricular systolic contractility (s’) increases to a greater extent in older, compared with younger subjects. The change in s’ was not associated with the change in core temperature in either age group. Supported by NIH R01AG069005 (CGC), F32HL154559 & K01HL160772 (JCW), and F32HL154565 (LNB). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Insulin-regulated aminopeptidase (IRAP) is required for appropriate dilution of urine after an acute water load
Authors: Zuchowski Yvonne , Carty Joshua , Trapani Jonathan , Bock Fabian , Terker Andrew , Zhang Mingzhi , Harris Raymond , Arroyo Juan Pablo 
Published: May 2023

Study Objective: Understand the response to acute water load in mice lacking the insulin-regulated aminopeptidase (IRAP). Hypothesis: IRAP degrades vasopressin in vivo, therefore, mice lacking IRAP would have impaired ability to dilute urine and to excrete water. Methods: Age matched 8–10-week-old IRAP WT and KO male mice were used for all experiments. Immunofluorescence and immunoblotting were performed on kidneys at baseline and after 1-hr acute water load (2ml sterile water/IP). Urine/serum electrolytes and urine osmolality were measured before and after water load. Urine was collected from IRAP WT and KO mice before and after 1-hr administration of OPC 31260 (10mg/kg/IP) and furosemide (2.5mg/ml/IP) for urine osmolality and electrolyte measurements. Results: IRAP is expressed in the glomerulus, thick ascending loop of Henle, distal tubule, connecting and collecting ducts. At baseline, IRAP WT and KO mice have similar systolic blood pressure (122 ± 6.6 vs 128 ± 1.9 mmHg), glomerular filtration rate (251 ± 20 vs 254 ± 16 uL/min), and serum Na+ levels (142 ± 1.9 vs 143 ± 2.6 mmol/L), but KO mice have reduced proteinuria (3.3 ± 0.57 vs 4.5 ± 1.6 mg/mg). At baseline, IRAP KO have elevated serum copeptin levels (111 ± 43 vs 53 ± 31 pg/mL) and urine osmolality compared to respective IRAP WT (2506 ± 310 vs 1007 ± 212 mOsm/L). Urine osmolality decreased in IRAP KO after administration of vasopressin type 2 receptor antagonist, OPC 31260 (473 ± 341 vs 2479 ± 215 mOsm/L) and loop diuretic, furosemide (517 ± 96 vs 2750 ± 414 mOsm/L). After an acute water load, IRAP KO have lower serum Na+ levels (127 ± 3.8 vs 134 ±3.1 mmol/L) and increased urine osmolality compared to IRAP WT (2741 ± 400 vs 577 ± 274 mOsm/L). Additionally, after an acute water load, IRAP KO mice also have higher protein abundance of the Na+/K+/2Cl- (NKCC2) co-transporter (0.36 ± 0.04 vs 0.20 ± 0.03 AU) and phosphorylation of water channel, AQP2 (0.032 ± 0.005 vs 0.025 ± 0.003 AU). Conclusions: IRAP is required to dilute urine and to increase water excretion in response to an acute water load due to persistent activation of NKCC2 and AQP2. Funding Sources: Harold Amos Medical Faculty Development Award - Robert Wood Johnson Foundation; Vanderbilt Center for Kidney Disease This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
The impacts of transportation on rodent research models
Authors: Abbaspour Raman 
Published: May 2023

There are well established links between excessive commuting and negative health consequences for humans. From a physiological perspective, commuting increases BMI and blood pressure while decreasing cardiorespiratory fitness and physical activity. From a psychological perspective, commuting increases sleep disorders and psychological stress. These negative consequences are also observed in animals. In addition to the adverse effects on the wellbeing of research animals, the impact of transportation threatens the scientific accuracy of our models. The intensive development, use and sharing of diverse rodent models in scientific studies, requires ongoing and at times global shipment of many animals. This transportation heavily impacts rodent physiology, including cardiovascular, endocrine, immune, and digestive systems. These all lead to changes in their neurophysiology and ultimately, behavior. If not accounted for, these practices will introduce confounding variables with the potential to conflate most studies. This review summarizes the research from the last 20 years in this area. Specifically, the effects of transportation on rodent physiology and behavior are reviewed. Through meta-analysis, these changes are quantified and analysed. Lastly, some recommendations for optimizing rodent transportation are discussed, to reduce the adverse effects of shipping and provide a means for mitigating this key but underappreciated aspect of contemporary animal research. Canada Research Chair Program and NSERC This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Adhering to occupational heat stress recommendations attenuates kidney injury risk
Authors: Hess Hayden , Baker Tyler , Tarr Macie , Johnson Blair , Hostler David , Schlader Zachary 
Published: May 2023

Occupational heat stress increases kidney injury (KI) risk due to the development of hyperthermia and dehydration. Workplace recommendations aim to maintain core temperature below 38.0°C and prevent dehydration (<2% body mass loss) in unacclimated workers. We hypothesized that KI risk would be attenuated when adhering to occupation heat stress recommendations compared to a work-matched positive control trial that was non-compliant with the recommendations. Twelve healthy adults (6 women) completed 4 h exposures to wet bulb globe temperatures of 30±2°C (Compliant [C]) and 36±0°C (Non-compliant [NC]). Subjects walked on a treadmill evoking a rate of metabolic heat production of 462±96 W. Consistent with the recommendations, work-rest ratios were prescribed as 15 min of walking and 45 min of rest per hour and subjects were provided 237 mL of sport drink every 15 min and drank ad libitum. Core temperature is presented as an average over the 4 h exposure. Percent change in body mass from pre- and postexposure provided an index of body water loss. Urine samples were collected preexposure, and immediately and 1 h postexposure. KI biomarkers of urinary insulin-like growth factor-binding protein 7 [IGFBP7] and tissue inhibitor of metalloproteinase 2 [TIMP-2] were measured and normalized to urine flow rate. The peak change in the product of IGFBP7 and TIMP-2 (Δ[IGFBP7xTIMP-2]) provided an overall index of KI risk. Data are presented as mean±SD. Average core temperature was lower in the C (37.3±0.3°C) compared to the NC (38.2±0.2°C; p<0.01) trial. Percent changes in body mass did not differ between the C (-0.3±0.6%) and NC (-0.7±1.0%; p=0.19) trials. UFR decreased from pre (C: 5.7±3.1 mL/min; NC: 5.2±3.1 mL/min) to postexposure (C: 2.2±1.8 mL/min; NC: 0.8±0.5 mL/min; p≤0.02) but was not different between trials (p=0.07) and returned to preexposure values 1 h postexposure (p≥0.21). IGFBP7 did not change over time (p=0.27) and was not different between trials (p=0.56). In contrast, TIMP-2 increased from preexposure (C: 0.2±0.2 ng/min; NC: 0.4±0.4 ng/min) to postexposure (C:7.1±17.7 ng/min; NC: 49.3±103.3 ng/min) in both trials (p≤0.01) and was higher in the NC trial both postexposure (p=0.02) and 1 h postexposure (C: 0.2±0.2 ng/min; NC 14.0±44.3 ng/min; p<0.01). Finally, peak Δ[IGFBP7xTIMP-2] was higher in the NC trial (+16.1±39.7 [ng/mL2]/1000) compared to the C trial (+0.8±1.5 [ng/mL2]/1000; p=0.02). Simulated occupational heat stress elevates KI risk, likely due to distal tubule injury as evident by increases in urinary TIMP-2. Nonetheless, violating the recommendations augmented KI risk when work duration was matched. RCT: NCT04767347. Supported By: R01OH011528 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.