Abstract 16165: Inorganic Arsenic Induces Sex-Dependent Pathological Cardiac Hypertrophy

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Raihan Kabir ◽  
Prithvi Sinha ◽  
Sumita Mishra ◽  
Obialunanma V Ebenebe ◽  
Nicole Taube ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Hypertrophy ◽  
Inorganic Arsenic ◽  
Left Ventricular ◽  
Luciferase Assay ◽  
Heart Weight ◽  
Left Ventricular Geometry ◽  
Wall Thickening ◽  
Pathological Cardiac Hypertrophy ◽  
Relevant Dose

Exposure to inorganic arsenic (iAS) through drinking water is well-associated with adverse cardiovascular outcomes, yet the mechanisms through which it induces these effects are not fully understood. Recent epidemiological findings highlight an association between iAS exposure and altered left ventricular geometry in both the presence and absence of hypertension. We therefore tested the hypothesis that iAS exposure has a bimodal impact on cardiac-intrinsic and hemodynamic mechanisms that together induce pathological remodeling of the myocardium. Adult male and female mice were exposed to an environmentally relevant dose of 615 μg/L NaAsO 2 for eight weeks. Males (n=9-10 mice/group) exhibited increased systolic blood pressure (115.1±3.0 vs. 106.0±2.3 mmHg, p=0.0350) via tail cuff photoplethysmography, left ventricular wall thickening (0.98±0.01 vs. 0.88±0.01 mm, p<0.0001) via transthoracic echocardiography, increased heart weight to tibia length (8.56±0.21 vs. 7.15±0.24 mg/mm; n=24 mice/group), and increased plasma atrial natriuretic peptide (47.85±12.0 vs. 15.14±3.73 pg/mL, p=0.0379) via enzyme immunoassay. Myocardial mRNA transcript levels (n=10 hearts/group) of Acta1 (1.36±0.18 vs. 0.73±0.11, p=0.0037), Myh7 (1.53±0.15 vs. 1.04±0.10, p=0.0138), and Nppa (2.40±0.29 vs. 1.02±0.07, p=0.0001) were increased, and Myh6 (0.92±0.17 vs. 1.14±0.23, p=0.0001) was decreased, evidencing pathological hypertrophy in the male heart. Female hearts, however, were largely protected at this eight-week timepoint as similar changes were not detected. Further investigation found that Rcan1 was upregulated (1.47±0.19 vs. 0.97±0.04, p=0.0161; n=10 hearts/group) in male hearts, suggesting that calcineurin-NFAT was activated. Interestingly, iAS was sufficient to activate NFAT (0.82±0.11 vs. 0.46±0.05, p=0.0214; n=8 wells/group) independent of blood pressure via luciferase assay. In conclusion, these results demonstrate for the first time that iAS may cause pathological cardiac hypertrophy not only by increasing hemodynamic load, but also by activating calcineurin-NFAT and inducing fetal gene expression in the male heart, thus providing novel mechanistic insight into the threat of iAS exposure to the cardiovascular system.

Inorganic Arsenic Induces Sex-Dependent Pathological Hypertrophy in the Heart

2021 ◽  
Author(s):  
Raihan Kabir ◽  
Prithvi Sinha ◽  
Sumita Mishra ◽  
Obialunanma V. Ebenebe ◽  
Nicole Taube ◽  
...  
Keyword(s):  
Cardiovascular Risk ◽  
Inorganic Arsenic ◽  
Left Ventricular ◽  
Neonatal Rat ◽  
Hek293 Cells ◽  
Luciferase Assay ◽  
Left Ventricular Geometry ◽  
Male And Female ◽  
Pathological Hypertrophy ◽  
The Impact

Arsenic exposure through drinking water is widespread and well-associated with adverse cardiovascular outcomes, yet the pathophysiological mechanisms by which inorganic arsenic (iAS) induces these effects are largely unknown. Recently, an epidemiological study in an American population with a low burden of cardiovascular risk factors found that iAS exposure was associated with altered left ventricular geometry. Considering the possibility that iAS directly induces cardiac remodeling independent of hypertension, we investigated the impact of an environmentally relevant iAS exposure on the structure and function of male and female hearts. Adult male and female C56BL/6J mice were exposed to 615 μg/L iAS for eight weeks. Males exhibited increased systolic blood pressure via tail cuff photoplethysmography, left ventricular wall thickening via transthoracic echocardiography, and increased plasma atrial natriuretic peptide via enzyme immunoassay. RT-qPCR revealed increased myocardial RNA transcripts of Acta1, Myh7, and Nppa, and decreased Myh6, providing evidence of pathological hypertrophy in the male heart. Similar changes were not detected in females, and nitric oxide dependent mechanisms of cardioprotection in the heart appeared to remain intact. Further investigation found that Rcan1 was upregulated in male hearts and that iAS activated NFAT in HEK293 cells via luciferase assay. Interestingly, iAS induced similar hypertrophic gene expression changes in neonatal rat ventricular myocytes, which were blocked by calcineurin inhibition, suggesting that iAS may induce pathological cardiac hypertrophy in part by targeting the calcineurin-NFAT pathway. As such, these results highlight iAS exposure as an independent cardiovascular risk factor and provide biological impetus for its removal from human consumption.

scholarly journals Blood Pressure, Left Ventricular Geometry, and Systolic Function in Children Exposed to Inorganic Arsenic

2015 ◽  
Vol 123 (6) ◽  
pp. 629-635 ◽  
Author(s):  
Citlalli Osorio-Yáñez ◽  
Julio C. Ayllon-Vergara ◽  
Laura Arreola-Mendoza ◽  
Guadalupe Aguilar-Madrid ◽  
Erika Hernández-Castellanos ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Systolic Function ◽  
Inorganic Arsenic ◽  
Left Ventricular ◽  
Left Ventricular Geometry ◽  
Ventricular Geometry

scholarly journals A systems approach using Diversity Outbred mice distinguishes the cardiovascular effects and genetics of circulating GDF11 from those of its homolog, myostatin

2021 ◽  
Author(s):  
Abigail E Starcher ◽  
Kristen Peissig ◽  
James B Stanton ◽  
Gary A Churchill ◽  
Dunpeng Cai ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Genetic Relationships ◽  
Cardiovascular Effects ◽  
Left Ventricular ◽  
Left Ventricular Wall ◽  
Heart Weight ◽  
Wall Thickening ◽  
Ventricular Wall ◽  
Regulatory Pathways ◽  
Diversity Outbred

Abstract Growth differentiation factor 11 (GDF11) is a member of the TGF-β protein family that has been implicated in the development of cardiac hypertrophy. While some studies have suggested that systemic GDF11 protects against cardiomyocyte enlargement and left ventricular wall thickening, there remains uncertainty about the true impact of GDF11 and whether its purported effects are actually attributable to its homolog myostatin. The present study was conducted to resolve the statistical and genetic relationships among GDF11, myostatin, and cardiac hypertrophy in a mouse model of human genetics, the Diversity Outbred (DO) stock. In the DO population, serum GDF11 concentrations positively correlated with cardiomyocyte cross sectional area, while circulating myostatin levels were negatively correlated with body weight, heart weight, and left ventricular wall thickness and mass. Genetic analyses revealed that serum GDF11 concentrations are modestly heritable (0.23) and identified a suggestive peak on murine chromosome 3 in close proximity to the gene Hey1, a transcriptional repressor. Bioinformatic analyses located putative binding sites for the HEY1 protein upstream of the Gdf11 gene in the mouse and human genomes. In contrast, serum myostatin concentrations were more heritable (0.57) than GDF11 concentrations, and mapping identified a significant locus near the gene FoxO1, which has binding motifs within the promoter regions of human and mouse myostatin genes. Together, these findings more precisely define the independent cardiovascular effects of GDF11 and myostatin, as well as their distinct regulatory pathways. Hey1 is a compelling candidate for the regulation of GDF11 and will be further evaluated in future studies.

P1606Glutamine-fructose-6-phosphate amidotransferase 2 mediates isoproterenol-induced cardiac hypertrophy by increasing Akt O-GlcNAcylation through hexosamine biosynthesis pathway

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A Ishikita ◽  
S Matsushima ◽  
S Ikeda ◽  
K Okabe ◽  
T Tadokoro ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Left Ventricular ◽  
Neonatal Rat ◽  
Heart Weight ◽  
Biosynthesis Pathway ◽  
Post Translational Modification ◽  
Expression Levels ◽  
Pathological Cardiac Hypertrophy ◽  
Hexosamine Biosynthesis ◽  
Hexosamine Biosynthesis Pathway

Abstract Background Cardiac hypertrophy is an independent risk factor for heart failure and cardiac death. Hexosamine biosynthesis pathway (HBP), an accessory pathways of glycolysis, is known to be involved in the attachment of O-linked N-acetylglucosamine motif (O-GlcNAcylation) to proteins, a post-translational modification. However, the role of HBP has not been determined in pathological cardiac hypertrophy. Purpose The purpose of this study to examine whether glutamine-fructose-6-phosphate amidotransferase 2 (GFAT2), a critical enzyme of HBP, mediates cardiac hypertrophy by protein O-GlcNAcylation and activating hypertrophic signaling in cardiomyocytes. Methods and results C57BL/6J mice were treated with isoproterenol (ISO: 15 mg/kg/day, 1 week) with or without 6-Diazo-5-oxo-L-norleucine (DON, an inhibitor of GFAT: 500 μg/kg/day, 1week). ISO-treated mice (ISO+vehicle) showed cardiac hypertrophy, which were attenuated in ISO and DON-treated mice (ISO+DON) (heart weight to tibial length ratio: 7.70±0.09 vs. 7.11±0.15 mg/mm, n=12, p<0.05, left ventricular wall thickness: 1.05±0.02 vs. 0.86±0.03 mm, n=6, p<0.05). Cardiomyocyte cross-sectional area was also decreased in ISO+DON compared with ISO+vehicle (309±25 vs. 252±13 mm2, n=,3 p<0.05). Whereas expression levels of GFAT2 and protein O-GlcNAcylation in the heart were increased in ISO+vehicle compared with control+vehicle by 3.3 and 1.5 folds, respectively (n=9 and n=9, p<0.05), expression levels of O-GlcNAc transferase (OGT) and the β-N-acetylglucosaminidase (OGA), other enzymes regulating O-GlcNAcylation, were not altered in both groups, indicating that ISO activated HBP by GFAT2. Protein O-GlcNAcylation in ISO+DON was lower than that in ISO+vehicle by 83% (n=9, p<0.05). In addition, phosphorylation of Akt, a critical mediator of cardiac hypertrophy, but not other mediators of cardiac hypertrophy such as ERK, JNK, or p38MAPK, was significantly decreased in ISO+DON by 76% (n=9, p<0.05). In cultured neonatal rat ventricular myocytes, treatment with ISO (1μM, 12h) increased the expression levels of GFAT2 and protein O-GlcNAcylation by 1.3 and 1.5 folds, respectively (n=6 and n=6, p<0.05), but not GFAT1. Furthermore, ISO stimulation increased a direct O-GlcNAcylation of Akt by 1.4 folds (n=3, p<0.05). Downregulation of GFAT2 by RNA silencing decreased cell size by 82% (n=6, p<0.05) and protein O-GlcNAcylation and phosphorylation of Akt by 76% and 54%, respectively (n=9 and n=9, p<0.05) in cardiomyocyte treated with ISO. Conversely, administration of glucosamine, a substrate of HBP, increased protein of O-GlcNAcylation and phosphorylation of Akt by 1.3 and 1.8 folds, respectively (n=6 and n=6, p<0.05). Conclusions GFAT2, a limiting enzyme of HBP, mediates pathological cardiac hypertrophy by Akt activation probably due to its O-GlcNAcylation. GFAT2-O-GlcNAcylation-Akt pathway might be a potential novel therapeutic target for cardiac hypertrophy.

scholarly journals The HDAC Inhibitor Emodin Blocks Hypertension-Induced Cardiac Hypertrophy: A Mediating Role for the Gut?

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 396-396
Author(s):  
Levi Evans ◽  
Brad Ferguson
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Cardiac Hypertrophy ◽  
Parent Compound ◽  
Heart Weight ◽  
Female Mice ◽  
Blood Institute ◽  
Mediating Role ◽  
Funding Sources ◽  
Pathological Cardiac Hypertrophy

Abstract Objectives Evidence suggests that food bioactives impact the epigenome to prevent pathological cardiac hypertrophy. Recently, we showed that emodin, an anthraquinone, attenuated pathological cardiac hypertrophy and histone deacetylase (HDAC) activity. However, we only examined the cardioprotective effects of emodin's parent compound, not of emodin metabolites or of emodin-gut microbiome interactions. The microbiome has emerged as a key player in chronic diseases such as metabolic and cardiac disease. Thus, we hypothesized that emodin could reverse hypertension-induced changes in microbial communities. Methods Normo- and hypertensive (angiotensin ii) C57/BL6 female mice were randomly assigned to receive vehicle (Veh, DMSO: PEG 1:1) or emodin (Emod, 30 mg/kg) for 14 days. Body weight was collected pre- and post-treatment and blood pressure assessed via tail-cuff. At study end, mice were euthanized and assessed for heart weight and fibrosis. In addition, stool samples and cecal content were collected to elucidate changes in microbial populations using 16S rRNA sequencing. Lastly, tissue was lysed and RNA isolated for RNA sequencing. One-way ANOVA with Tukey's post-hoc was performed unless otherwise specified and P &lt; 0.05 considered significant. Results Emodin significantly attenuated cardiac hypertrophy and fibrosis in female mice. No significant changes were observed for body weight or systolic blood pressure in response to hypertension or emodin. Lastly, preliminary analysis suggests that hypertension altered the microbiome, with evidence to support that emodin effects gut microbiota. Conclusions Our data demonstrates that emodin attenuates pathological hypertrophy and fibrosis in female mice. Whether this attenuation in cardiac remodeling is driven, in part, by the actions of emodin on the gut the microbiome remains unclear and is currently an active topic of investigation in our lab. Funding Sources This work is supported by the USDA NIFA (Hatch-NEV00767), the Dennis Meiss & Janet Ralston Fund for Nutri-epigenetic Research, the National Institute for General Medical Sciences (NIGMS) of the NIH (P20 GM130459) and the National Heart, Lung, and Blood Institute of the NIH (R15 HL143496) to B.S.F. Core facilities used for Research were supported by NIGMS of the NIH (P20 GM103554).

Reversibility of cold-induced hypertension after removal of rats from cold

1990 ◽  
Vol 68 (7) ◽  
pp. 830-835 ◽  
Author(s):  
Orit Shechtman ◽  
Paula E. Papanek ◽  
Melvin J. Fregly
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Cardiac Hypertrophy ◽  
Cold Exposure ◽  
Adrenal Glands ◽  
Treated Group ◽  
Left Ventricular ◽  
Male Rats ◽  
Heart Weight ◽  
Renal Hypertrophy

Chronic exposure of rats to cold air induces hypertension, including elevation of blood pressure and cardiac hypertrophy. The present study was designed to assess reversibility of these changes after removal from cold. Five groups of six male rats each were exposed to cold (5 ± 2 °C) for 39 days, while six control rats were maintained at 26 ± 2 °C. Systolic blood pressures of the rats in one of the cold-treated groups, as well as the controls, were measured twice weekly throughout the experiment. Blood pressure of the cold-exposed rats (150 ± 3 mmHg; 1 mmHg = 133.3 Pa) became elevated significantly above that of controls (129 ± 3 mmHg) within 4 weeks. On day 39 of cold exposure, one group (six rats) of the cold-treated rats was sacrificed while still in the cold. The remaining four groups of cold-treated rats were than removed from cold and kept at 26 ± 2 °C. One group of cold-treated rats was sacrificed weekly thereafter. During the last week, the six control rats were also sacrificed. At death, the heart, kidneys, and adrenal glands were removed and weighed. Mean heart weight of the cold-treated group (346 ± 7 mg/100 g body weight), sacrificed prior to removal from cold, was significantly (p < 0.01) greater than that of controls (268 ± 5 mg/100 g body weight). The increased heart weight of the cold-treated group appeared to result mainly from an increase in left ventricular weight. The weights (mg/100 g body weight) of the kidneys and adrenal glands of cold-treated rats, measured prior to removal from cold, were significantly (p < 0.01) greater than those of controls. Two weeks after removal from cold, blood pressure, heart weight, and left ventricular weight decreased from the levels observed prior to removal from cold. However, they were still significantly greater than those of controls through the fourth week after removal from cold. Thus, the hypertension accompanying a 39-day exposure to cold appears to be only partially reversible at 4 weeks after removal from cold.Key words: cold exposure, hypertension, blood pressure, reversibility of hypertension, renal hypertrophy, cardiac hypertrophy.

scholarly journals A G-protein-biased S1P1 agonist, SAR247799, improved LVH and diastolic function in a rat model of metabolic syndrome

2021 ◽  
Author(s):  
Maria Francesca Evaristi ◽  
Bruno Poirier ◽  
Xavier Chénedé ◽  
Anne-Marie Lefebvre ◽  
Alain Roccon ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Metabolic Syndrome ◽  
Cardiac Hypertrophy ◽  
Diastolic Dysfunction ◽  
Diastolic Function ◽  
G Protein ◽  
Rat Model ◽  
Left Ventricular ◽  
Heart Weight ◽  
Functional Components

Aim: Heart failure with preserved ejection fraction (HFpEF) is a major cause of death worldwide with no approved treatment. Left ventricular hypertrophy (LVH) and diastolic dysfunction represent the structural and functional components of HFpEF, respectively . Endothelial dysfunction is prevalent in HFpEF and predicts cardiovascular events. We investigated if SAR247799, a G-protein-biased sphingosine-1-phosphate receptor 1 (S1P 1 ) agonist with endothelial-protective properties, could improve cardiac and renal functions in a rat model of metabolic syndrome LVH and diastolic function. Methods: 31- and 65-week-old obese ZSF1 (Ob-ZSF1) rats, representing young and old animals with LVH and diastolic dysfunction, were randomized to a chow diet containing 0.025% (w/w) of SAR247799, or control (CTRL) chow for 4 weeks. Age-matched lean ZSF1 (Le-ZSF1) rats were fed control chow. Echocardiography, telemetry, biochemical and histological analysis were performed to evaluate the effect of SAR247799. Results: Echocardiography revealed that Ob-ZSF1 rats, in contrast to Le-ZSF1 rats, developed progressive diastolic dysfunction and cardiac hypertrophy with age. SAR247799 blunted the progression of diastolic dysfunction in young and old animals: in young animals E/e’ was evaluated at 21.8 ± 1.4 for Ob-ZSF1-CTRL, 19.5 ± 1.2 for Ob-ZSF1-SAR247799 p<0.01, and 19.5 ± 2.3 for Le-ZSF1-CTRL (median ± IQR). In old animals E/e’ was evaluated at 23.15 ± 4.45 for Ob-ZSF1-CTRL, 19.5 ± 5 for Ob-ZSF1-SAR247799 p<0.01, and 16.69 ± 1.7 for Le-ZSF1-CTRL, p<0.01 (median ± IQR). In old animals, SAR247799 reduced cardiac hypertrophy (mean ± SEM of heart weight/tibia length 0.053 ± 0.001 for Ob-ZSF1-CTRL vs 0.046 ± 0.002 for Ob-ZSF1-SAR247799 p<0.01, Le-ZSF1-CTRL 0.035 ± 0.001) and myocardial perivascular collagen content (p<0.001), independently of any changes in microvascular density. In young animals, SAR247799 improved endothelial function as assessed by the very low frequency bands of systolic blood pressure variability (mean ± SEM 67.8 ± 3.41 for Ob-ZSF1-CTRL  55.8 ± 4.27 or Ob-ZSF1-SAR247799, p<0.05  and 57.3 ± 1.82 Le-ZSF1-CTRL), independently of any modification of arterial blood pressure. In old animals, SAR247799 reduced urinary protein/creatinine ratio, an index of glomerular injury, (10.3 ± 0.621 vs 8.17 ± 0.231 for Ob-ZSF1-CTRL vs Ob-ZSF1-SAR247799, respectively, p<0.05 and 0.294 ± 0.029 for Le-ZSF1-CTRL, mean ± SEM) and the fractional excretion of electrolytes. Circulating lymphocytes were not decreased by SAR247799, confirming lack of S1P 1 desensitization.   Conclusions: These experimental findings suggest that S1P 1 activation with SAR247799 could improve LVH, cardiac diastolic and renal function in HFpEF patients .

Abstract 19428: TRAF3IP2 Mediates Aldosterone-induced Cardiac Hypertrophy and Fibrosis

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Siddesha Jalahalli Mariswamy ◽  
Siva Sankara Vara Prasad Sakamuri ◽  
Yariswamy Manjunath ◽  
Anthony J Valente ◽  
Ulrich Siebenlist ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Hypertrophy ◽  
Protein Expression ◽  
Gene Deletion ◽  
Heart Diseases ◽  
Critical Role ◽  
Left Ventricular ◽  
Heart Weight ◽  
Electrolyte Balance ◽  
Gene And Protein Expression

Background: Aldosterone (Aldo) is a key regulator of blood pressure and electrolyte balance. Aldo/salt has been shown to induce oxidative stress, inflammation, cardiac hypertrophy and fibrosis. TRAF3 interacting protein 2 (TRAF3IP2) is a cytoplasmic redox-sensitive adaptor molecule and an upstream regulator of NF-κB and AP-1. It plays a critical role in the regulation of various proinflammatory cytokines that exert prohypertrophic and profibrotic effects. Therefore, we hypothesized that TRAF3IP2 is a critical mediator of Aldo/salt-induced cardiac hypertrophy and fibrosis. Methods: TRAF3IP2-null and wild type (WT) mice (male, 12-13 weeks) were infused continuously with Aldo for 4 weeks via mini-osmotic pumps (0.2 mg/Kg/day; n = 6-8). Mice were fed 1% NaCl in drinking water. Salt alone served as control. Systolic blood pressure (SBP) was measured by tail-cuff plethysmography, myocardial function by echocardiography, cardiac hypertrophy by heart weight to body weight ratios, cardiac fibrosis by trichrome Gomori, and gene and protein expression by RT-qPCR, immunoblotting and ELISA. Results: Aldo/salt elevated SBP to a similar extent in both TRAF3IP2-null and WT mice. Aldo/salt upregulated TRAF3IP2 expression in left ventricular homogenates from WT mice, and TRAF3IP2 gene deletion (vs. WT) blunted cardiac hypertrophy by 54% (p < 0.05), suppressed ANP expression by 3.5 fold (p < 0.05), prevented concentric LV remodeling (decreased LVPWs; 93%; p < 0.01, LVPWd; 95%; p < 0.05, LVAWs; 29.8%; p < 0.05 and LVAWd; 26.2%, and increased LVIDs; 19.2%; p < 0.01 and LVIDd; 8.53%) and markedly reduced both interstitial and perivascular fibrosis. Further, TRAF3IP2 gene deletion inhibited Aldo/salt-induced p65 and c-Jun activation, and expression of inflammatory cytokine (IL-18 and IL-6), matrix metalloproteinase (MMP2) and extracellular matrix proteins (collagen Iα1 and IIIα1). TRAF3IP2 gene deletion also blunted mRNA and protein expression of lysyl oxidase, an enzyme involved in collagen crosslinking. Conclusions: TRAF3IP2 gene deletion blunts Aldo/salt-induced cardiac hypertrophy and fibrosis by inhibiting proinflammatory, prohypertrophic, and profibrotic effects, signifying its potential as a therapeutic target in hypertrophic heart diseases.

scholarly journals A G-protein-biased S1P1 agonist, SAR247799, improved LVH and diastolic function in a rat model of metabolic syndrome

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0257929
Author(s):  
Maria Francesca Evaristi ◽  
Bruno Poirier ◽  
Xavier Chénedé ◽  
Anne-Marie Lefebvre ◽  
Alain Roccon ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Metabolic Syndrome ◽  
Cardiac Hypertrophy ◽  
Diastolic Dysfunction ◽  
Diastolic Function ◽  
G Protein ◽  
Rat Model ◽  
Left Ventricular ◽  
Heart Weight ◽  
Functional Components

Aim Heart failure with preserved ejection fraction (HFpEF) is a major cause of death worldwide with no approved treatment. Left ventricular hypertrophy (LVH) and diastolic dysfunction represent the structural and functional components of HFpEF, respectively. Endothelial dysfunction is prevalent in HFpEF and predicts cardiovascular events. We investigated if SAR247799, a G-protein-biased sphingosine-1-phosphate receptor 1 (S1P1) agonist with endothelial-protective properties, could improve cardiac and renal functions in a rat model of metabolic syndrome LVH and diastolic function. Methods 31- and 65-week-old obese ZSF1 (Ob-ZSF1) rats, representing adult and aged animals with LVH and diastolic dysfunction, were randomized to a chow diet containing 0.025% (w/w) of SAR247799, or control (CTRL) chow for 4 weeks. Age-matched lean ZSF1 (Le-ZSF1) rats were fed control chow. Echocardiography, telemetry, biochemical and histological analysis were performed to evaluate the effect of SAR247799. Results Echocardiography revealed that Ob-ZSF1 rats, in contrast to Le-ZSF1 rats, developed progressive diastolic dysfunction and cardiac hypertrophy with age. SAR247799 blunted the progression of diastolic dysfunction in adult and aged animals: in adult animals E/e’ was evaluated at 21.8 ± 1.4 for Ob-ZSF1-CTRL, 19.5 ± 1.2 for Ob-ZSF1-SAR247799 p<0.01, and 19.5 ± 2.3 for Le-ZSF1-CTRL (median ± IQR). In aged animals E/e’ was evaluated at 23.15 ± 4.45 for Ob-ZSF1-CTRL, 19.5 ± 5 for Ob-ZSF1-SAR247799 p<0.01, and 16.69 ± 1.7 for Le-ZSF1-CTRL, p<0.01 (median ± IQR). In aged animals, SAR247799 reduced cardiac hypertrophy (g/mm mean ± SEM of heart weight/tibia length 0.053 ± 0.001 for Ob-ZSF1-CTRL vs 0.046 ± 0.002 for Ob-ZSF1-SAR247799 p<0.01, Le-ZSF1-CTRL 0.035 ± 0.001) and myocardial perivascular collagen content (p<0.001), independently of any changes in microvascular density. In adult animals, SAR247799 improved endothelial function as assessed by the very low frequency bands of systolic blood pressure variability (mean ± SEM 67.8 ± 3.41 for Ob-ZSF1-CTRL 55.8 ± 4.27 or Ob-ZSF1-SAR247799, p<0.05 and 57.3 ± 1.82 Le-ZSF1-CTRL), independently of any modification of arterial blood pressure. In aged animals, SAR247799 reduced urinary protein/creatinine ratio, an index of glomerular injury, (10.3 ± 0.621 vs 8.17 ± 0.231 for Ob-ZSF1-CTRL vs Ob-ZSF1-SAR247799, respectively, p<0.05 and 0.294 ± 0.029 for Le-ZSF1-CTRL, mean ± SEM) and the fractional excretion of electrolytes. Circulating lymphocytes were not decreased by SAR247799, confirming lack of S1P1 desensitization. Conclusions These experimental findings suggest that S1P1 activation with SAR247799 may be considered as a new therapeutic approach for LVH and diastolic dysfunction, major components of HFpEF.

Increased cardiac ppENK mRNA in cardiac hypertrophy and effects on blood pressure of its peptide products

1997 ◽  
Vol 272 (6) ◽  
pp. H2885-H2894 ◽  
Author(s):  
J. M. Hao ◽  
S. W. Rabkin
Keyword(s):  
Blood Pressure ◽  
Cardiac Hypertrophy ◽  
Isolated Heart ◽  
Left Ventricular ◽  
High Salt ◽  
Heart Weight ◽  
Mrna Levels ◽  
High Salt Diet ◽  
Salt Diet ◽  
Heart Preparation

The objective of this study was to examine the expression of preproenkephalin (ppENK) in the heart in cardiac hypertrophy and the effects on cardiac contractility and blood pressure regulation of its peptide products. The ppENK-derived peptides Leu5-enkephalin (LE), Met5-enkephalin (ME), Met5-enkephalin-Arg6-Gly7-Leu8 (MEAGL), and Met5-enkephalin-Arg6-Phe7 (MEAP) were administered intravenously to unanesthetized Sprague-Dawley rats and to an isolated heart preparation from the same species. LE, ME, MEAGL, or MEAP (360 nmol iv) produced an immediate decrease in heart rate, reaching its maximum within 10 s and returning to baseline by 30 s. The blood pressure response for each enkephalin was a small initial decrease followed by a marked and significant increase (P < 0.05 for MEAP). In the isolated heart preparation, neither LE, ME, MEAGL, nor MEAP altered left ventricular contractility. Cardiac hypertrophy was produced in the Dahl salt-dependent model of hypertension with a significantly greater heart weight-to-body weight ratio in the Dahl salt-sensitive (S) compared with the Dahl salt-resistant (R) rat on a high-salt diet (P < 0.05). Tissue RNA was extracted, and Northern blot analysis identified and quantitated mRNA with a 0.93-kilobase cDNA of ppENK A. There was more ppENK mRNA in the left than in the right ventricle and much less in the atria than in the ventricles. The amount of ppENK mRNA was markedly and significantly increased in the left ventricle of the Dahl S compared with the Dahl R rat (P < 0.05). In contrast, there were no differences in ppENK mRNA levels in different brain regions between the R and S rats on a high-salt diet. Interestingly, a larger ppENK mRNA of 1.75 kilobases was abundantly expressed in testicular tissue. These data showing increased ppENK expression raise the possibilities of 1) an autocrine/paracrine role for enkephalins in cardiac hypertrophy and 2) an endocrine role for the hypertrophic heart, with an increased production of enkephalins, especially MEAP, that produces vasoconstriction and further increases in blood pressure.

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