bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of cardioprotective effects of high concentration of magnesium on hypoxia/reoxygenation injury in chronic magnesium deficient rat heart are differ from normal rat heart (LB665)
Authors: Watanabe Makino , Nakamura Kyoko , Kato Megumi , Kakigi Ryo , Iesaki Takafumi , Okada Takao
Published: June 2021

Magnesium (Mg) deficiency has been reported to be associated with the development of cardiovascular diseases. We have reported that high concentration (12 mM) of extracellular Mg during hypoxia (high‐Mg) protected the heart from hypoxia/reoxygenation (H/R) injury, and its protective effect was induced not only by suppression of energy consumption, but also by opening of mitochondrial KATP channel in cardiomyocytes. The aim of this study was to determine whether high‐Mg could protect the H/R injury in chronic Mg‐deficient (Mg‐def) rat heart. Rats were fed an Mg‐def diet for 8 weeks, and the hearts were subjected to Langendorff perfusion with the protocol of 30 min hypoxia followed by 30 min reoxygenation. In Mg‐def group, the recovery of cardiac function (pressure‐rate product; PRP) from H/R injury was significantly impaired than that of control group. Recovery of PRP in Mg‐def group was restored to that of control group when extracellular Mg concentration was increased from 1.2 to 12 mM during hypoxia. A specific mitochondrial KATP channel blocker, 5‐hydroxy decanoic acid (5‐HD), did not inhibit the protective effect of high‐Mg in Mg‐def group. In isolated myocardial mitochondria from Mg‐def rat hearts, retention of Ca2+ to open the mitochondrial permeability transition pore (mPTP) was significantly lower than that of control group. These results suggest that the mechanisms of cardioprotective effects of high‐Mg do not depend on opening the mitochondrial KATP channel but on unknown other mechanisms, although the mitochondrial functions are impaired in Mg‐def rat hearts.

Grant Funding Source: Supported by JSPS KAKENHI Grant Number 24614015
Continuous blood pressure assessment from a photoplethysmographic signal with Deep Belief Networks (LB674)
Authors: Ribas Vicent
Published: June 2021

Continuous blood pressure assessment from a photoplethysmographic signal with Deep Belief Networks Vicent J. Ribas Ripoll PhD; Anna Wojdel PhD; Anna Sáez de Tejada Cuenca; Juan C. Ruiz‐Rodríguez, MD; Adolf Ruiz‐Sanmartín, MD; Miriam de Nadal MD, PhD; Enrique Romero PhD; Alfredo Vellido PhD A prospective study was conducted at a critical care department and post‐anesthesia care unit of a university teaching hospital in Barcelona, Spain. The study recruited 707 patients with invasive BP and finger PPG waves over a period of 26 months. Exclusion criteria were presence of major arrhythmia, immediate death condition and disturbances in the arterial or PPG curve morphology. For each patient we automatically recorded the systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP) and PPG curve for 30 minutes. The PPG signal was further processed to obtain a set of features that were used to construct a Deep Belief Network with Gaussian Restricted Boltzmann Machine (DBN‐RBM). The available dataset was split into three subsets (Training, Validation and Testing). The training and validation datasets included 85% of data and the testing dataset included 15% of the available data. The regression error was assessed through a Bland‐Altman analysis and the AAMI standard. The mean prediction error were ‐2.98+‐19.35 mmHg for SBP, ‐3.38+‐10.35 mmHg for MAP and 3.65+‐8.69 mmHg for DBP.

The results obtained are promising for the assessment of MAP and DBP with DBN‐RBM. Further research and clinical validation are needed to bring this technology to standard medical practice.

Grant Funding Source: Supported by Shockomics (FP7 framework)
Cell survival effects of an mTOR‐binding protein Tel2 in cardiomyocytes (LB682)
Authors: Yorichika Naaiko , Matsui Takashi
Published: June 2021

Recent studies including ours suggest that the mechanistic target of rapamycin (mTOR) is sufficient and necessary to prevent cardiomyocyte (CM) cell death against pathological stresses such as myocardial infarction. We also showed that the expression level of mTOR increases in patients and mice with heart failure. However, a mechanism of regulating mTOR expression in the heart remains unknown. Recent reports showed that telomere maintenance 2 (Tel2) interacts with mTOR and regulates its stability and abundance in other tissues. To assess the role of Tel2 in CMs, we examined whether Tel2 is sufficient to stabilize cardiac mTOR and prevent cell death against hypoxic stress. CM cell line HL‐1 cells were transiently overexpressed with Tel2 and then subjected to 24‐hour hypoxia. Cell survival was assessed by morphological changes and Cell Death Detection ELISA (Roche). The necessity of Tel2 was examined by the treatment of CMs with Tel2‐specific siRNA. Western blotting showed overexpression of Tel2 increased the expression level of mTOR by 60% (p<0.05, n=5), and the phosphorylation levels of both S6 (mTORC1 substrate) and Akt (mTORC2 substrate) (90%‐ and 60%‐increase, respectively; p<0.05, n=5). The CMs treated with siRNA targeting Tel2 showed significant decrease in the expression level of mTOR, and the phosphorylation levels of both S6 and Akt compared to controls (p<0.05, n=3). In the hypoxic culture, the round‐shape CMs, indicating cell injury, were less in Tel2‐overexpressed CMs. Cell Death ELISA showed that hypoxia increased apoptosis by 4‐fold compared to baseline controls, whereas Tel2 overexpression suppressed apoptosis by half compared to controls (p<0.05, n=3). These findings suggest that an mTOR‐binding protein Tel2 is sufficient and necessary to protect CMs against hypoxia at least in part by mTOR stabilization. A study of Tel2‐mediated mTOR activation would provide a novel target for a therapy of heart failure following myocardial infarction.

Grant Funding Source: Supported by NIH R01 HL098423
Maternal diet and ovariectomy modify blood pressure response to Nω‐nitro‐L‐arginine methyl ester (LNAME) in the rat (LB684)
Authors: Clifford Bethan , Langley‐Evans Simon , Elmes Matthew
Published: June 2021

It is well established that the developmental programming of hypertension occurs through dietary manipulations during pregnancy but the role of sex in developmental programming is not well understood. The study at hand aimed to further elucidate the mechanisms behind sexual dimorphism in blood pressure regulation using an established model of nutritional programming.

Female Wistar rats were mated and allocated to a control (18% casein; C) or low protein (9% casein; LP) diet during gestation. At 10 weeks of age, female offspring were ovariectomised (OVX) or exposed to a sham surgery procedure. At 11 months of age all animals underwent aortic telemetry implantation. Blood pressure and heart rate were recorded for a 6 week period, including baseline recordings and treatment with the nitric oxide synthase inhibitor LNAME.

LNAME induced a significant increase in blood pressure (~20mmHg, p< 0.001), in accordance with previous studies. A significant interaction was observed between surgery and diet groups (p<0.02) with differences between sham‐ and OVX females in the C and LP groups being reversed. OVX in C animals decreased systolic blood pressure by ~6mmHg compared to sham animals. In contrast OVX in LP animals, increased systolic blood pressure readings ~8mmHg higher than in sham animals.

Gestational exposure to a LP diet results in altered blood pressure response to OVX surgery.

Grant Funding Source: BBSRC
Carotid body removal reduces cardiac sympathetic tone 5 days after myocardial infarction in rats. (LB685)
Authors: Silva Carlos Alberto , Salgado Helio , Fazan Rubens
Published: June 2021

We investigated whether ablation of the carotid body (CBX) ameliorates autonomic imbalance caused by myocardial infarction (MI) in rats. MI was induced by coronary ligation (CL) in male Wistar rats 5 days before the experiments. 24 h after CL the animals were submitted to CBX (N=7) or sham surgery (N=9) and instrumented for chronic ECG recording. On the day of the experiment basal ECG was recorded in conscious rats followed by iv injection of propranolol (2 mg/kg). The heart rate (HR) response to propranolol was used as index of cardiac sympathetic tone and the autonomic imbalance was examined by HR variability analysis (FFT and symbolic analysis of RR interval). After ECG recordings the animals were anesthetized (sodium pentobarbital) and instrumented with a catheter to measure left ventricular pressure. HR was similar in both groups (358±11 vs 372±10 bpm). Overall variability, as well as LF/HF ratio of RR spectra, were also similar between infarcted rats subjected to CBX (2.1±0.4 ms and 0.33±0.16) or sham surgery (3.2±0.8 ms and 0.36±0.16). Symbolic analysis of RR interval failed to reveal differences between groups. Nevertheless, HR response to propranolol was smaller in rats with CBX (‐27±2 vs ‐50±2 bpm) showing a beneficial effect of this maneuver in reducing the sympathetic tone in infarcted rats. Cardiac function evaluated by pressure measurements in left ventricle was not affected by CBX.
Apocynin and tempol restores cutaneous microvascular function in healthy, salt‐resistant adults on a high sodium diet (LB686)
Authors: Ramick Meghan , Brian Michael , Matthews Evan , Lennon‐Edwards Shannon , Farquhar William , Edwards David
Published: June 2021

The purpose of this study was to determine if NADPH derived superoxide plays a role in attenuating cutaneous vasodilation in response to local heating in healthy, salt‐resistant adults on a high sodium diet. Nineteen healthy adults (33±3yrs) participated in a controlled feeding study. Subjects completed 7 days of a low sodium (LS) diet (20mmol sodium/day) and 7 days of a high sodium (HS) diet (300mmol sodium/day) in random order. On the final day of LS and HS diets cutaneous microvascular function was assessed using a standard heating protocol. RBC flux was measured via laser Doppler flowmetry coupled with interdermal microdialysis for the local delivery of 10µM tempol (scavenging superoxide) and 100 µM apocynin (inhibiting NADPH oxidase). Once a stable post‐heating plateau was achieved, 10mM L‐NAME was infused through all sites to determine NO contribution to vasodilation. The plateau phase of cutaneous vasodilation was attenuated in the HS condition compared to LS (91.0±1.8 vs 83.4±1.9; p<0.05) and was restored with the local infusion of both tempol and apocynin (p<0.05). The NO contribution to cutaneous vasodilation was also decreased on the HS diet compared to LS (62.7±4.2 vs 52.3±4.6; p<0.05). This was restored with the infusion of apocynin (p< 0.05) but was not improved by tempol (p=0.173). These finding suggest that NADPH derived superoxide plays a role in dietary sodium induced decreases in cutaneous vasodilation in response to local heating.

Grant Funding Source: Supported by NIH Grant R01 HL104106‐01A1
Effect of chronic Angiotensin II infusion on plasma TNFalpha and IL 6 levels in adiponectin deficient mice (LB687)
Authors: O'Brien Alexis , Smith Minnette , Pamidimukkala Jaya
Published: June 2021

Chronic low grade inflammation plays an integral part in the development of many types of cardiovascular diseases. Adipose tissue is a well known source of many proinflammatory mediators. Adiponectin (APN) is one of the few proteins secreted by the adipose tissue that is known to have anti‐inflammatory properties. Our research goal is to understand if APN deficiency contributes to a proinflammatory milieu especially when provided with an appropriate stimulus. Angiotensin II (ANGII) is a well known prohypertensive agent. Recently, ANGII has emerged as a growth factor and stimulator of proinflammatory cytokine expression in cardiovascular & renal tissue. The present study evaluates the effect of chronic Angiotensin II infusion on plasma TNFAlpha and IL 6 levels. Briefly, male C57BL/6J mice and Adiponectin deficient mice (adipo ‐/‐) were implanted with osmotic pumps containing Angiotensin II (ANGII, 800ng/Kg body weight/min) or Saline. Plasma levels of TNFalpha and IL6 were measured using enzyme linked immunoabsorbent assay (ELISA) kits. After two weeks of chronic infusion of ANGII, plasma TNFalpha levels in adiponectin deficient mice (n=6, 11.85±1.54 pg/ml) were not significantly different from the control C57Bl/6J mice (n=6, 9.88±1.17pg/ml). Plasma IL6 levels were also not significantly different in the two groups. In conclusion, adiponectin deficiency did not result in a proinflammatory milieu in the circulation even in the presence of a inflammatory stimulus such as ANGII.
TLR3‐induced expression patterns of human placental microRNAs (LB705)
Authors: Jamison Ashley , Jupiter Daniel , Chatterjee Piyali
Published: June 2021

OBJECTIVE: Preeclampsia (PE) is a pregnancy‐specific hypertensive disorder that affects 5‐8% of women worldwide. The placenta is considered to be the main culprit as symptoms of PE typically reduce following delivery of the placenta. This study was designed to determine the effects of TLR3 activation on placental miRNA expression and whether these miRs are associated with PE in women.

METHODS: Microarray for miRNAs was performed in human cytotrophoblasts (CTBs) treated with poly I:C for 24 hour and compared with vehicle‐treated CTBs. The expression of 10 miRNAs (5 upregulated and 5 downregulated) were confirmed by qRT‐PCR. Formalin fixed paraffin embedded placental tissues were obtained from patients with PE (n= 9‐11) and normal pregnant women (n = 6‐8) and the expression of these miRNAs were assessed by qPCR.

RESULTS: Both human CTBs treated with poly I:C and placentas of PE women exhibited increased expression of miR‐155 and miR‐125a‐5p and decreased expression of miR‐575, miR‐149*, and miR‐145. Gene Ontology analysis of the target genes using miRTarBase revealed enrichment for specific biological process categories (chromatin binding and cell death: miR‐155; cell cycle and proliferation: miR‐145).

CONCLUSIONS: Here we demonstrate that alterations in the expression of specific miRNAs induced by TLR3 activation in CTB were also observed in PE women. These data provide novel targets for further investigation into the pathophysiology of PE.

Grant Funding Source: 13SDG14630018
D‐4F‐mediated reduction in metabolites of arachidonic and linoleic acids in the small intestine is associated with decreased inflammation in low‐density lipoprotein receptor‐null mice (LB708)
Authors: Aram Negar , Reddy Srinivasa , Anantharamaiah G. , Hough Greg , Buga Georgette , Danciger Jan , Fogelman Alan , Navab Mohamad
Published: June 2021

Our group hypothesized that intestine is a major site of action for D‐4F, low‐density lipoprotein receptor null (LDLR) mice were fed a Western diet (WD) and administered the peptide subcutaneously (SQ) or orally. Plasma and liver D‐4F levels were 298‐fold and 96‐fold higher, respectively, after SQ administration, whereas D‐4F levels in small intestine were similar whether D‐4F was administered orally or SQ. Levels of metabolites of arachidonic and linoleic acids known to bind with high affinity to D‐4F were significantly reduced in intestine, liver and hepatic bile to a similar degree whether administered SQ or orally. However, levels of 20‐hydroxyeicosatetraenoic acid (HETE), which is known to bind the peptide with low affinity, were unchanged. D‐4F treatment reduced plasma serum amyloid A (SAA) and triglyceride levels and increased HDL‐cholesterol levels after SQ or oral administration. Plasma levels of metabolites of arachidonic and linoleic acids significantly correlated with SAA levels. Feeding 15‐HETE chow diet (without WD) significantly increased plasma SAA and triglyceride levels and decreased HDL‐cholesterol and paraoxonase activity, all of which were significantly enhanced by SQ D‐4F. Our group concludes that D‐4F administration reduces levels of free metabolites of arachidonic and linoleic acids in the small intestine and this is associated with decreased inflammation in LDLR null mice.
Expression of collagen type 1a1 and 3a1 isoforms in aortic adventitial fibroblast cultured from ovariectomized and intact Long Evans rats (LB715)
Authors: Ringel Veronica , Boyd Denise , Novak Jacqueline , Ramirez Rolando , Underwood Adam
Published: June 2021

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The prevalence of cardiovascular disease is lower in premenopausal women when compared to equally aged men. Decreased arterial compliance may contribute to the increased risk. This reduced vascular compliance can be attributed to increases in adventitial collagen deposition in the postmenopausal state. The goal of this project was to determine if collagen type 1a1 and 3a1 are expressed differently in aortic fibroblasts cultured from an animal model of post‐menopausal physiology; surgically ovariectomized Long Evans rats and control animals with ovaries intact and subjected to a sham surgery. Fibroblasts were established in T‐25 flasks from 0.5‐1.5 mm sections of thoracic aorta isolated from three ovariectomized and control animals. Fibroblasts were grown for seven days in Dulbecco’s Modified Eagles Medium (DMEM) containing 15% FBS and then passed and cultured for 48 hours in DMEM containing 10% FBS. Immunodetection of the proteins desmin and vimentin was used to verify fibroblast identity. Prior to RNA extraction all cells were incubated for 72 hours in DMEM clear. After cDNA synthesis, the relative expression (∆∆CT) of collagens 1a1 and 3a1 was determined using real‐time PCR and 18S as an endogenous control. From these runs it was determined that collagen 1a1 and 3a1 expression is 1.6 and 1.4 fold higher respectively in fibroblasts isolated from ovariectomized rats when compared to the control. This indicates that lack of ovarian hormones can lead to increased adventitial collagen expression, which may reduce arterial compliance. Studies focusing on the influence of hormones, such as relaxin, on collagen expression are underway.

Grant Funding Source: Supported by NIH 1R15HL09343
Sympathetic neural recruitment during severe chemoreflex stimulation (LB732)
Authors: Badrov Mark , Usselman Charlotte , Shoemaker J. Kevin
Published: June 2021

Sympathetic neural recruitment during severe chemoreflex stimulation Mark B. Badrov1, Charlotte W. Usselman1, J. Kevin Shoemaker1,2: 1School of Kinesiology, 2Department of Physiology and Pharmacology, Western University, London, Ontario, Canada This study tested the hypothesis that severe chemoreflex stress stimulates the recruitment of sub‐populations of previously silent, larger amplitude sympathetic action potentials. Muscle sympathetic nerve activity was measured via microneurography in 7 healthy males (27 ± 2 yrs, 180 ± 4 cm, 82 ± 13 kg; mean ± SD) at baseline and during a maximal end‐inspiratory apnea, which was preceded by a rebreathing protocol designed to elicit progressive hypoxia and hypercapnia, thereby maximizing the severity of sympathoexcitation evoked during the subsequent apnea (End‐apnea: PO2 = 58 ± 4 Torr; PCO2 = 55 ± 5 Torr). Compared to baseline, burst frequency (19 ± 6 to 43 ± 10 bursts/min; P < 0.01), burst incidence (37 ± 12 to 73 ± 11 bursts/100 heartbeats; P < 0.01), and mean normalized burst amplitude (30 ± 6 to 56 ± 6 AU; P < 0.001) were increased during apnea. For sympathetic action potential analyses, action potential frequency (211 ± 205 to 617 ± 354 spikes/min; P < 0.01), action potential incidence (408 ± 400 to 1068 ± 598 spikes/100 heartbeats; P < 0.001), and mean action potential content per burst (10 ± 6 to 15 ± 9 spikes/burst; P < 0.05) were increased during apnea compared to baseline. Furthermore, the total number of distinct amplitude‐based ‘clusters’ of action potentials increased from 15 ± 5 at baseline to 19 ± 8 during apnea (P < 0.05). This was concomitant with an increase in the number of distinct ‘clusters’ per sympathetic burst (5 ± 2 to 6 ± 3 clusters/burst; P < 0.01) during apnea. In conclusion, a neural recruitment strategy exists whereby previously silent sub‐populations of larger amplitude action potentials are recruited as sympathetic activity is elevated during periods of severe chemoreflex stress.

Grant Funding Source: Supported by NSERC and CIHR
Improved efficacy of metformin therapy when combined with caloric restriction in the treatment of type 2 diabetes and NAFLD in OLETF rats (LB743)
Authors: Linden* Melissa , Lopez* Kristi , Fletcher Justin , Meers Grace , Siddique Sameer , Morris E. , Crissey Jacqueline , Kearney Monica , Laughlin M. , Sowers James , Thyfault John , Ibdah Jamal , Rector R.
Published: June 2021

Weight loss is recommended for nonalcoholic fatty liver disease (NAFLD) patients while metformin may lower liver enzymes in type 2 diabetics. Yet, the efficacy of the combination of treatments on NAFLD is unclear. We sought to assess the effects of metformin, caloric restriction, and the combination on NAFLD in diabetic Otsuka Long‐Evans Tokushima Fatty (OLETF) rats. OLETF rats were (age 20 weeks; n=6‐8/group) fed ad libitum (AL), given metformin (300 mg/kg/d; Met), caloric restricted (70% of AL fed; CR), or CR+Met for 12 weeks. Met lowered body weight and adiposity compared with AL, but was less effective than CR and CR+Met (p<0.05). All therapies improved fasting insulin, glucose, and/or HbA1c, but only CR+Met improved post‐challenge glucose tolerance. Met, CR, and CR+Met reduced hepatic triglycerides by 40%, 70%, and 60% (p<0.05 Met vs. CR/CR+Met groups), respectively compared to AL rats; however, CR+Met further attenuated serum alanine aminotransferase levels. Only CR altered hepatic de novo lipogenesis proteins fatty acid synthase (FAS), acetyl‐CoA carboxylase (ACC), and stearoyl‐CoA desaturase‐1 (SCD‐1) and hepatic mitochondrial activity (palmitate oxidation and β‐hydroxy‐acyl‐CoA dehydrogenase (β‐HAD) activity). ACC and SCD‐1 protein content were further reduced with CR+Met. The combination of caloric restriction + metformin further benefited glycemic control, liver injury, and markers of hepatic de novo lipogenesis compared with either therapy alone in the diabetic OLETF rat. *co‐first authorship.

Grant Funding Source: Supported by: NIH HL‐36088, DK‐088940, HL73101‐07, HL107910‐03, and T32 AR‐048523 and VA Merit System 0018 and CDA2‐1299.
Vitamin D Status and its Correlation with Blood Pressure Among Saudi Postmenopausal Women: A Cross‐Sectional Study (LB755)
Authors: Al Marhoumi Lujain , Al Kadi Hanan
Published: June 2021

The aim of the present study was to assess the correlation between vitamin D status and blood pressure (BP) in a group of Saudi postmenopausal women.

METHODS: This cross‐sectional study was conducted in the “Center of Excellence for Osteoporosis Research” (CEOR), King Abdulaziz University (KAU), Jeddah, Saudi Arabia, from March‐May 2013. The study population included 31 Saudi women (52‐70 years old), randomly selected from “Primary Health Care Centers” in Jeddah, Saudi Arabia. Blood pressure was measured by a standardized method using an automated BP monitor (BPTru). Anthropometric measurements were obtained and fasting blood samples were collected. Serum 25‐hydroxyvitamin D [25(OH) D] and parathyroid hormone (PTH) were measured by sandwich chemiluminescence immunoassay method.

RESULTS: Vitamin D deficiency was highly prevalent among the study group with 68% of the women having levels <50 nmol/L and 39% having levels <25 nmol/L. In all women combined, 25(OH) D level was inversely associated with both systolic (r=‐0.39; P=0.028) and diastolic (r=‐0.39; P=0.030) BP. Blood pressure was higher in the group with severe vitamin D deficiency (<25 nmol/L), but this did not reach statistical significance. Linear regression analysis showed that 25(OH) D was independently and inversely associated with diastolic BP.

CONCLUSION: In Saudi postmenopausal women, vitamin D deficiency is highly prevalent and 25(OH) D level was independently and inversely associated with diastolic BP. Correction of vitamin D deficiency in this high risk group is needed and may improve BP control in hypertensive postmenopausal women. Interventional studies to evaluate if attainment of optimal vitamin D status may prevent hypertension are necessary.

Grant Funding Source: Supported by the Center of Excellence for Osteoporosis Research, King Abdulaziz University, Jeddah, Saudi Arabia
Adropin Enhances Glucose Disposal and Cardiovascular Function in Rats (LB761)
Authors: Stein Lauren , Samson Willis , Yosten Gina
Published: June 2021

Adropin, a hormone encoded by the Energy Homeostasis Associated gene, has been demonstrated in mice to enhance glucose tolerance (Cell Metabolism 8:468, 2008) and in cultured, human endothelial cells to exert a protective role via up‐regulation of endothelial NO synthase expression in a manner consistent with activation of a G protein‐coupled receptor (Circulation 122:S185, 2010). We examined potential effects of adropin in conscious male rats and observed a significant effect of intravenously applied adropin on glucose disposal in a modified glucose tolerance test. A rapid and significant effect of adropin to lower basal glucose levels was observed. A similar dose of adropin, given i.v., significantly elevated mean arterial pressure in unrestrained male rats, with slow onset (circa 7 minutes) and relatively long duration (circa 30 min). Thus in the rat, as in mice, adropin appears to enhance insulin sensitivity and, in the rat at least, cardiovascular actions can be predicted. While existing gene compromise and over expression models also support a role for adropin in glucose homeostasis and metabolism, we believe the ultimate physiologic relevance of the hormone, and all of its potential actions, will be established only once its cognate receptor is identified, its localization mapped and consequences of its deletion determined.
Depletion of white adipocyte progenitors suppresses obesity development (LB763)
Authors: Daquinag Alexes , Tseng Chieh , Salameh Ahmad , Zhang Yan , Kolonin Mikhail
Published: June 2021

The study objective is to test a new approach to obesity prevention. Overgrowth of white adipose tissue (WAT) in obesity occurs as a result of adipocyte hypertrophy and hyperplasia. Expansion and renewal of adipocytes relies on proliferation and differentiation of white adipocyte progenitors (WAP), however, the requirement of WAP for obesity development has not been proven. Here, we investigate whether depletion of WAP can be used to prevent WAT expansion. We test this approach by using a hunter‐killer peptide designed to induce apoptosis selectively in WAP. We show that targeted WAP cytoablation results in a long‐term WAT growth suppression despite increased caloric intake in a mouse diet‐induced obesity model. Our data indicate that WAP depletion results in a compensatory beige adipocyte differentiation from an alternative progenitor cell population. Consistent with reported thermogenic capacity of beige adipose tissue, WAP‐depleted mice display increased energy expenditure. We conclude that targeting of adipocyte progenitors could be developed as a strategy to modulate WAT metabolic activity.

Grant Funding Source: American Heart Association and Cancer Prevention and Research Institute of Texas
The Zucker Diabetic Fatty (ZDF)rat as a model for assessment of anti‐diabetic therapies (LB766)
Authors: Cornicelli Joseph , Rocheford Erik , Fisher Diane , Countey Barbara , Spencer‐Pierce Jennifer , Hoffman Jay , Barry MaryEllen , Dhawan Rajeev
Published: June 2021

Diabetes and obesity have taken on epidemic proportions worldwide. In order to develop effective therapies against these disorders, translatable animal models that closely mimic the human disease are necessary for assessing therapeutic potential. The Zucker diabetic fatty (ZDF) rat is obese, hyperglycemic, insulin resistant and hyperlipidemic. This study defined the development of the diabetic phenotype in this model and assessed the activity of the standard anti‐diabetic treatments metformin, glyburide, pioglitazone, sitagliptin, as well as the anti‐inflammatory agent salsalate in this animal model over time. Pioglitazone was most effective in increasing glycemic control as measure by fasting and non‐fasting blood glucose, glucose tolerance and insulin tolerance. Metformin also improved glycemic control, although much more modestly. Glyburide exacerbated the diabetic phenotype in the rats, presumably by accelerating insulin secretion and beta cell failure. Interestingly, the anti‐inflammatory agent salsalate also improved the response to an insulin tolerance test. Assessment of various further support the notion that the ZDF rat can be used to assess agents designed to treat diabetes.
Artemisia scoparia enhances adipocyte development and endocrine function in vitro and enhances insulin action in vivo (LB771)
Authors: Fuller Scott , Richard Allison , Fedorcenco Veaceslav , Ribnicky David , Stephens Jacqueline
Published: June 2021

Background: Failure of adipocytes to expand during periods of energy excess can result in undesirable metabolic consequences. Blinded screening studies have indicated that Artemisia scoparia (SCO) extracts can enhance adipocyte differentiation and lipid accumulation in cultured adipocytes. The present study tested the hypothesis that SCO treatment modulates fat cell development and function in vitro and insulin sensitivity in adipose tissue in vivo.

Methods: In vitro experiments utilized a Gal4‐PPAR[[Unsupported Character ‐ Symbol Font □]] ligand binding domain (LBD) fusion protein‐luciferase reporter assay to examine PPAR[[Unsupported Character ‐ Symbol Font □]] activation. Neutral lipid accumulation, gene expression, and protein secretion were measured by Oil Red O staining, qRT‐PCR, and immunoblotting, respectively. For the in vivo experiments, diet‐induced obese (DIO) C57BL/6J mice were fed a high‐fat diet (HFD) or HFD containing 1% w/w SCO for four weeks. Body weight and composition, food intake, and fasting glucose and insulin levels were measured. Phospho‐activation and expression of insulin‐sensitizing proteins in epididymal adipose tissue (eWAT) were measured by immunoblotting.

Results: Ethanolic extracts of A. scoparia significantly activated the PPAR[[Unsupported Character ‐ Symbol Font □]] LBD and enhanced lipid accumulation in differentiating 3T3‐L1 cells. SCO increased the transcription of several PPAR[[Unsupported Character ‐ Symbol Font □]] target genes in differentiating 3T3‐L1 cells and rescued the negative effects of tumor necrosis factor [[Unsupported Character ‐ Symbol Font □]] on production and secretion of adiponectin and monocyte chemoattractant protein‐1 in fully differentiated fat cells. DIO mice treated with SCO had elevated adiponectin levels and increased phosphorylation of AMPK[[Unsupported Character ‐ Symbol Font □]] in eWAT when compared to control mice. In SCO‐treated mice, these changes were also associated with decreased fasting insulin and glucose levels.

Conclusion: SCO has metabolically beneficial effects on adipocytes in vitro and adipose tissue in vivo, highlighting its potential as a metabolically favorable botanical supplement.

Grant Funding Source: Supported by NIH 2P30DK072476
Triheptanoin alters anaplerosis and glutamate production in the chronic pilocarpine model of epilepsy (LB78)
Authors: McDonald Tanya , Hodson Mark , Borges Karin
Published: June 2021

Growing evidence suggests that dysfunctions in glucose metabolism that reduce ATP production play a role in the pathophysiology of epilepsy. Triheptanoin, an anaplerotic molecule through propionyl‐CoA carboxylase (PCC) pathway is anticonvulsant in four rodent seizure models. We aim to determine the effects of triheptanoin on brain glucose metabolism in chronic epilepsy. Mice were fed a standard or 35% (caloric value) triheptanoin diet for three weeks following pilocarpine injections, which results in spontaneous recurrent seizures in mice that developed status epileptics (SE) (n= 7‐15 mice per group). The levels of glycolytic and TCA cycle metabolites in hippocampal tissue were measured by LCMS‐MS. Spectrophotometric enzyme assays measured the activity levels of enzymes involved in these pathways. The levels of several glycolytic intermediates were reduced in SE mice, independent of diet (Two way ANOVAs p<0.05). Despite a reduction in levels of glycolytic intermediates there was no change in enzyme activity (Two‐way ANOVA P>0.05) suggesting that glucose uptake is reduced. In SE mice pyruvate carboxylase activity increased indicating an increased requirement for anaplerosis. This increase was attenuated by triheptanoin feeding, suggesting an alternate anaplerotic pathway is utilised. Furthermore triheptanoin increased the activity of aspartate transaminase and glutamate dehydrogenase, indicating an increase in glutamate production. Overall this study suggests that triheptanoin entry via PCC refills TCA cycle intermediates, allowing increased production of glutamate. The fate of this glutamate still needs to be investigated.
Role of endothelial connexin 43 during recovery from lipopolysaccharide‐induced lung injury in rats (LB784)
Authors: Kandasamy Kathirvel , Escue Rachel , Parthasarathi Kaushik
Published: June 2021

We showed endothelial Cx43 gap junctions mediate permeability in lung microvessels. However, whether Cx43 gap junctions modulate lung microvessel permeability during recovery from an inflammatory insult is unknown. Toward this, we instilled rats with lipopolysaccharide (LPS; 2mg/kg; IT). Rats were allowed to recover for 1, 5 or 14 days. At each recovery period, the animals’ lungs were isolated and perfused with autologous blood. The pulmonary artery, left atrial and airway pressures were maintained at 10, 3 and 5 cmH2O, respectively. Via a left atrial microcatheter, we loaded microvessels with the Ca2+ indicator, fluo4 AM and Ca2+ cage, NP‐EGTA AM. Uncaging in microvessels of untreated control lungs revealed that, fluo4 fluorescence increased by 39±11% (mean±SEM; n=5 vessels) at 80 µm from the uncaging site compared to that at 0 µm. In contrast, at 5 days post‐LPS treatment the fluorescence increased only 6±2% (P<0.05, n=6). At day 14, fluorescence increase was back at control levels. Further, we determined single microvessel permeability via normalized fluorescence of FITC‐dextran (FDx20) infused into microvessels. The permeability was high at day 1 post LPS treatment (1.9±0.1; n=15 vessels) compared to control (3.6±0.2; P<0.05; n=15). In contrast, permeability recovered by day 5 (3±0.1; n=15) and returned to control levels by day 14. Together the data suggest both interendothelial communication and microvessel permeability were continuously modulated during recovery from LPS‐injury. Thus we speculate, changes in Cx43‐dependent interendothelial communication may underlie decrease in microvessel permeability during recovery from LPS‐injury.

Grant Funding Source: '' Supported by NIH HL75503''
Acid Sensing Ion Channels contribute to hypoxia‐induced migration in human pulmonary arterial smooth muscle cells (LB788)
Authors: Yellowhair Tracylyn , Nitta Carlos , Herbert Lindsay , Jernigan Nikki
Published: June 2021

Our laboratory has recently shown that acid sensing ion channel 1 (ASIC1) contributes to the arterial remodeling associated with chronic hypoxia‐induced pulmonary hypertension. This is consistent with the reported involvement of ASIC in migration, proliferation, and apoptosis in a variety of cells types. However, the contribution of ASIC to hypoxia‐induced migration, proliferation, and apoptosis has not been examined. Therefore, we hypothesize that ASIC1 and ASIC3 contribute to hypoxia‐induced migration in human pulmonary arterial smooth muscle cells (hPASMC). To test this hypothesis, hPASMC were grown to confluence and placed into basal media 24 hr prior to executing an in‐vitro scratch assay. Following the scratch, hPASMC were treated with a non‐selective ASIC inhibitor, amiloride; the specific ASIC1 inhibitor, psalmotoxin 1; the specific ASIC3 inhibitor, APETx2; or vehicle and then exposed to normoxia (21% oxygen, 5% CO2) or hypoxia (2% oxygen, 5% CO2) for 12 hrs. Inhibition of ASIC1 and ASIC3 did not alter migration of hPASMC exposed to normoxia, but prevented the hypoxia‐induced migration. This data demonstrates that ASIC1 and ASIC3 contribute to hypoxia‐induced migration in hPASMCs and describes a potential mechanism in which ASIC contributes to pulmonary arterial remodeling. We will further examine the specific role of ASIC1 and ASIC3 in hypoxia‐induced proliferation and apoptosis.
Impact of Hydroxylase inhibitors on fibrosis associated with IBD (LB789)
Authors: Cabrero Manresa Mario , Tambuwala Murtaza , Cavadas Miguel , Cummins Eoin , Cheong Alex , Taylor Cormac
Published: June 2021

Fibrosis is a major complication of inflammatory bowel disease (IBD) which cannot be adequately addressed with pharmacologic therapy. In IBD the treatment of fibrosis usually requires surgical resection of colonic segments and is responsible for 75% of surgical interventions in Crohn’s disease (CD). Pharmacological inhibition of hydroxylases ameliorates inflammation in multiple models of IBD. We hypothesized that hydroxylase inhibition may also impact fibrosis in IBD. To test this, the effect of the hydroxylase inhibitor DMOG was tested using an in vivo model of IBD. Mice given 2.5% dextran sodium sulphate (DSS) in drinking water for 5 days and allowed natural recovery for 14 days, developed inflammation and fibrosis, as shown by higher inflammation score, higher submucosal collagen‐I deposition and increased fibroblast infiltration through the colonic mucosa. Mice treated with intra peritoneal DMOG, exhibited less inflammation and lower collagen accumulation, as well as reduced fibroblast infiltration. To test whether this antifibrotic action was secondary to the anti‐inflammatory effect or due to a direct anti fibrotic action, an in vitro model was used. Fibroblasts were treated with TGF‐β1, the key mediator of healing and fibrosis. DMOG was given to the cells prior to TGF‐β1, and α‐smooth muscle actin (α‐SMA) and collagen‐I were analyzed as key fibrosis markers. Both markers were reduced by hydroxylase inhibitors in the presence of TGF‐β1, suggesting a direct antifibrotic action in fibroblasts. Furthermore, this effect was related to a reduced expression of Smad‐3 in human colonic fibroblast, a central effector of the TGF‐β pathway. In conclusion, hydroxylase inhibition reduces fibrosis in vitro and in vivo affecting, at least in part, the TGF‐β pathway. That could be a starting point to search for therapies that can ameliorate fibrosis in this and other diseases.

Grant Funding Source: Supported by Science Foundation Ireland
Differential Cardiac Responses to Prolonged Hyperoxia vs. Hypoxia Exposures (LB795)
Authors: Howden Reuben , Heimer Heidi , Cividanes Samantha , Zacherle Emily , Arthur Susan , Bagge Annika , Huet Yvette
Published: June 2021

Introduction. Pulmonary edema, reduced pulmonary gas exchange and systemic hypoxia can be induced or exacerbated by hyperoxia (high FiO2). Systemic hypoxia or prolonged hyperoxia have both been associated with bradycardia. Hence, hyperoxia‐induced bradycardia, pulmonary edema and systemic hypoxia may be related. The purpose of this study was to assess the contribution of hypoxia to known hyperoxia‐induced bradycardia.

Methods. Male C57BL/6J mice (8‐12 wks; 20‐30g; n = 8‐10 per group) were exposed to hyperoxia (100% O2), hypoxia (10% O2) or room air for 55 hours while ECG was recorded. Heart rate (HR), QT‐interval (QTcB) and PR‐interval (PR‐I) responses were calculated from the ECG waveforms.

Results. 55hrs hyperoxia induced a substantial reduction in HR and QTcB, compared to baseline (~365bpm HR; ~98ms QTcB; P<0.05), air controls and hypoxia‐exposed mice. Further, an increase in PR‐I, compared to baseline (~19ms; P<0.05), was found in the hyperoxia exposed mice only, to which increases in P‐wave duration contributed the most.

Conclusion. This study suggests that if prolonged hyperoxia induces systemic hypoxia, the hypoxia does not contribute to the established hyperoxia‐induced bradycardia.

Grant Funding Source: Supported by UNC Charlotte
Does arterial stiffness change under hyperbaric conditions? (LB796)
Authors: Kurtev Angel , Kumar Nakul , Kodali Ahalya , Donnawell Kayla
Published: June 2021

One of the effects of hyperbaric environment is considered to be peripheral vasoconstriction due to high oxygen tension. It was proposed that this could yield to changes in vascular properties, and to further investigate the issue we examined stiffness index (SI) and reflection index (RI) as calculated from a finger photoplethysmography under normobaric and hyperbaric environment. Eight subjects participated in the study comprising three different conditions spread over one session ‐ breathing air at 1 ATA, breathing air at 2 ATA and breathing 100% oxygen at 2 ATA. Each condition lasted for at least 10 minutes. Photoplethysmography and EKG were continuously recorded using Biopac MP100 multi‐modular system (BIOPAC Systems Inc., Goleta, CA). The compression was done in a multi‐place hyperbaric chamber (Clucas Diving Ltd).

The results showed no overall differences in SI and RI when comparing the three conditions. For each subject however there were significant changes in the studied parameters, although in different directions. These findings suggest that SI and RI do change in hyperbaric environment. They also argue that at short exposure and low pressure the vascular effects most probably were not fully developed in order to overcome the inter‐individual differences. Such notion was also supported by the observed stable heart rate in all three conditions and the concomitant small changes in heart rate variability.

Grant Funding Source: Saba Ubniversity School of Medicine
Angiotensin II receptor blockade protects against the slow to fast fiber type shift and type I fiber atrophy in the rat soleus with 7 days of hindlimb unloading (LB804)
Authors: Hord Jeffrey , Lee Yang , Lawler John
Published: June 2021

Reduced mechanical loading during spaceflight and immobilization results in weakening and atrophy of antigravity skeletal muscles. Data indicates that oxidative stress contributes to inactivity‐induced muscle atrophy. Recently we observed that the Nox2 isoform of NADPH oxidase is upregulated during unloading‐induced soleus muscle atrophy. Clues from other tissue types indicate activation of angiotensin II type 1 receptor (AT1R) as an upstream event leading to Nox2 complex formation and activity. Here, we used an AT1R blocker (Losartan) to test the hypothesis that AT1R activation is an upstream signaling event driving Nox2 complex activity, and thus atrophy in the mechanically unloaded soleus. Rats were divided into 4 groups: ambulatory control (CON), ambulatory + Losartan (40 mg/kd/day) (CON‐L), hindlimb unloaded for 7 days (HU), and HU + Losartan (HU‐L). Losartan treatment did not protect against the reduction in soleus mass during 7 days of unloading. However, the increase in Type II muscle fibers seen with unloading was mitigated by Losartan administration. Losartan also protected against atrophy of Type I muscle fibers. In addition, Losartan reduced the signal intensity and membrane localization of the Nox2 subunit p67phox in the unloaded soleus. Our findings suggest a potential role of AT1R activation as an upstream signaling event leading to Nox2 complex formation, activation, and slow to fast fiber‐type shift during mechanical unloading.

Grant Funding Source: Supported by NASA (NNX13AE45G), Predoctoral Space Physiology Grant from ACSM/NASA, and the Sydney and J.L. Huffines Institute
Effects of aerobic exercise on capillary architecture of extensor digitorum Longus in Rat (LB807)
Authors: Murakami Shinichiro , Sakita Masahiro , Kondo Hiroyo , Kanazashi Miho , Tanaka Masayuki , Tanaka Minoru , Ohtuka Aiji , Momota Ryusuke , Fujino Hidemi
Published: June 2021

Purpose: Aerobic exercise training is effective training to slow oxidative muscles like soleus. Anaerobic exercise training can induce an increase number of capillaries, fiber cross‐sectional area, VDGF, succinate dehydrogenase activities and the peroxisome PGC1‐α in slow oxidative muscle, but less is known about the effects of fast glycolytic muscle. Our aim is to clarify that effect of Aerobic exercise training on fast glycolytic muscle. We used rat extensor digitorum longus in this study. That is a well‐known one of the fast glycolytic muscle.Materials/Methods: Twelve male Wistar rats were randomly divided into exercise and control (Cont) groups. Rats in the exercise group performed running on a treadmill with an incline for 30 min, 6 days per week during 2 weeks. The intensity level of exercise was 3‐5 mg/dl in plasma lactate. To investigate the fiber type and fiber cross‐sectional area (FCSA), the mitochondrial oxidative activity, and the capillary density (CD) in skeletal muscle were stained with adenosine triphosphatase (ATPase), succinate dehydrogenase (SDH) and alkaline phosphatase (AP), respectively. In addition, the peroxisome proliferator‐activated receptor gamma coactivator 1α (PGC‐1α), vascular endothelial growth factor (VEGF), and vascular endothelial growth factor receptor 2 (Flk‐1) in skeletal muscle were expressed relative to the mean obtained in Cont group. Results: From a confocal laser microscopic evaluation, the microvessel volume and capillary diameter of the muscle in the exercise group was higher than those of Cont group although no changes in FCSA and CD were found in the exercise group. The SDH activity of the exercise group was higher than that of the Cont group. In addition, the level of PGC‐1α protein content in the muscle of the exercise group had increased by 237 %, compared with that of Cont muscle. Whereas no difference was observed in the VEGF expression level between two groups, the expression level of Flk‐1 in the exercise group was higher than that of the Cont group. Conclusions and Clinical Relevance: These results indicate that exercise induced‐angiogenesis is deeply involved in Flk‐1 expression in skeletal muscle.
Acute lipid administration inhibits amino acid induced phosphorylation of translation repressor 4E‐BP1 in human muscle in an apparent mTOR independent manner (LB813)
Authors: Murton Andrew , Chee Carolyn , Wall Benjamin , van Loon Luc , Tsintzas Kostas , Stephens Francis
Published: June 2021

At this conference we show that lipid induced insulin resistance is accompanied by impairments in the ability of amino acids (AA) to stimulate muscle protein synthesis in healthy young men, but the mechanism by which this occurs remains unknown. Here we investigated whether the response of mTOR signaling to AA provision is diminished following lipid infusion. 7 male volunteers (23 ± 1 y, 24 ± 1 kg/m2) underwent a 7 h i.v. infusion of either saline or 10% Intralipid (100 ml/h; Fresenius Kabi) on 2 randomised occasions. After 4 h, a 21 g AA bolus was administered intragastrically and the remaining 3 h period performed under euglycaemic (4.5 mmol/L) hyperinsulinemic (50 mU/m2/min) clamp conditions. Key mTOR signaling processes were examined by qPCR and western blot in vastus lateralis biopsies obtained at 4 and 7 h. Irrespective of lipid infusion, hyperinsulinemia and AA feeding resulted in significantly (P<0.05) reduced mRNA levels of two purported suppressors of mTOR activity, REDD1 (saline: 33% and lipid: 50% decline) and KLF15 (saline: 75% and lipid: 74% decline), concomitant to increases in AKT (saline: 93% and lipid: 84% increase; P<0.01) and mTOR (saline: 66% and lipid: 54% increase; P<0.05) phosphorylation. In contrast, lipid infusion blunted the increase of phosphorylation of the downstream translation repressor 4E‐BP1 in response to AA and insulin (saline: 193% (P<0.001) and lipid: 19% increase (NS)). Thus, acute lipid infusion impairs phosphorylation of 4E‐BP1 by AA and insulin in an apparent AKT and mTOR independent manner in healthy young subjects.

Grant Funding Source: Supported by a British Nutrition Foundation Drummond Pump Priming Award to A. Murton