Different Anti-contractile Function And Nitric Oxide Production Of Thoracic And Abdominal Perivascular Adipose Tissues

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Divergent phenotypes between the perivascular adipose tissue (PVAT) surrounding the abdominal and the thoracic aorta might be implicated in regional aortic differences, such as susceptibility to atherosclerosis. Although PVAT of the thoracic aorta exhibits anti-contractile function, the role of PVAT in the regulation of the vascular tone of the abdominal aorta is not well defined. In the present study, we compared the anti-contractile function, nitric oxide (NO) availability, and reactive oxygen species (ROS) formation in PVAT and vessel walls of abdominal and thoracic aorta. Abdominal and thoracic aortic tissue from male Wistar rats were used to perform functional and molecular experiments. PVAT reduced the contraction evoked by phenylephrine in the absence and presence of endothelium in the thoracic aorta, whereas this anti-contractile effect was not observed in the abdominal aorta. Abdominal PVAT exhibited a reduction in endothelial NO synthase (eNOS) expression compared with thoracic PVAT, without differences in eNOS expression in the vessel walls. In agreement with this result. NO production evaluated in situ using 4,5-diaminofluorescein was less pronounced in abdominal compared with thoracic aortic PVAT, whereas no significant difference was observed for endothelial NO production. Moreover, NOS inhibition with L-NAME enhanced the phenylephrine-induced contraction in endothelial-denuded rings with PVAT from thoracic but not abdominal aorta. ROS formation and lipid peroxidation products evaluated through the quantification of hydroethidine fluorescence and 4-hydroxynonenal adducts, respectively, were similar between PVAT and vessel walls from the abdominal and thoracic aorta. Extracellular superoxide dismutase (SOD) expression was similar between the vessel walls and PVAT of the abdominal and thoracic aorta. However, Mn-SOD levels were reduced, while CuZn-SOD levels were increased in abdominal PVAT compared with thoracic aortic PVAT. In conclusion, our results demonstrate that the anti-contractile function of PVAT is lost in the abdominal portion of the aorta through a reduction in eNOS-derived NO production compared with the thoracic aorta. Although relative SOD isoforms are different along the aorta. ROS formation, and lipid peroxidation seem to be similar. These findings highlight the specific regional roles of PVAT depots in the control of vascular function that can drive differences in susceptibility to vascular injury.7Eundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [14/07947-6, 14/20303-0]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq grant) [447507/2014-1]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Protective Role of Perivascular Adipose Tissue in Endothelial Dysfunction and Insulin-Induced Vasodilatation of Hypercholesterolemic LDL Receptor-Deficient Mice

Background: Endothelial dysfunction plays a pivotal role in the initiation of atherosclerosis. Vascular insulin resistance might contribute to a reduction in endothelial nitric oxide (NO) production, leading to impaired endothelium-dependent relaxation in cardiometabolic diseases. Because perivascular adipose tissue (PVAT) controls endothelial function and NO bioavailability, we hypothesized a role for this fat deposit in the vascular complications associated with the initial stages of atherosclerosis. Therefore, we investigated the potential involvement of PVAT in the early endothelial dysfunction in hypercholesterolemic LDL receptor knockout mice (LDLr-KO).Methods: Thoracic aortas with and without PVAT were isolated from 4-month-old C57BL/6J (WT) and LDLr-KO mice. The contribution of PVAT to relaxation responses to acetylcholine, insulin, and sodium nitroprusside was investigated. Western blotting was used to examine endothelial NO synthase (eNOS) and adiponectin expression, as well the insulin signaling pathway in aortic PVAT.Results: PVAT-free aortas of LDLr-KO mice exhibited impaired acetylcholine- and insulin-induced relaxation compared with those of WT mice. Both vasodilatory responses were restored by the presence of PVAT in LDLr-KO mice, associated with enhanced acetylcholine-induced NO levels. PVAT did not change vasodilatory responses to acetylcholine and insulin in WT mice, while vascular relaxation evoked by the NO donor sodium nitroprusside was not modified by either genotype or PVAT. The expression of insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase (PI3K), AKT, ERK1/2, phosphorylation of AKT (Ser473) and ERK1/2 (Thr202/Tyr204), and adiponectin was similar in the PVAT of WT and LDLr-KO mice, suggesting no changes in PVAT insulin signaling. However, eNOS expression was enhanced in the PVAT of LDLr-KO mice, while eNOS expression was less abundant in PVAT-free aortas.Conclusion: These results suggest that elevated eNOS-derived NO production in aortic PVAT might be a compensatory mechanism for the endothelial dysfunction and impaired vasodilator action of insulin in hypercholesterolemic LDLr-deficient mice. This protective effect may limit the progression of atherosclerosis in genetic hypercholesterolemia in the absence of an atherogenic diet

Spironolactone Prevents Endothelial Nitric Oxide Synthase Uncoupling And Vascular Dysfunction Induced By Beta-adrenergic Overstimulation Role Of Perivascular Adipose Tissue

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Sustained stimulation of beta-adrenoceptors (beta-ARs) and activation of renin-angiotensin-aldosterone system are common features of cardiovascular diseases with rising sympathetic activation, including essential hypertension, myocardial infarction, and heart failure. In this study, we investigated the role of AT1 receptor and mineralocorticoid receptor (MR) in the vascular alterations caused by beta-AR overstimulation. beta-AR overstimulation with associated cardiac hypertrophy and increased vasoconstrictor response to phenylephrine in aorta were modeled in rats by 7-day isoproterenol treatment. The increased vasoconstrictor response to phenylephrine in this model was blunted by the MR antagonist spironolactone, but not by the AT1 receptor antagonist losartan, despite the blunting of cardiac hypertrophy with both drugs. Spironolactone, but not losartan, restored NO bioavailability in association with lower endothelial nitric oxide synthase-derived superoxide production, increased endothelial nitric oxide synthase dimerization, and aortic HSP90 upregulation. MR genomic and nongenomic functions were activated in aortas from isoproterenol-treated rats. Isoproterenol did not modify plasma levels of MR ligands aldosterone and corticosterone but rather increased perivascular adipose tissue-derived corticosterone in association with increased expression of 11 beta-hydroxysteroid dehydrogenase type 1. The anticontractile effect of aortic perivascular adipose tissue was impaired by beta-AR overstimulation and restored by MR blockade. These results suggest that activation of vascular MR signaling contributes to the vascular dysfunction induced by beta-AR overstimulation associated with endothelial nitric oxide synthase uncoupling. These findings reveal an additional explanation for the protective effects of MR antagonists in cardiovascular disorders with sympathetic activation.683726Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP Brazil) [14/07947-6, 11/15972-2]Ministerio de Educacion Cultura y Deporte [PHBP14/00001]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Taurine Supplementation Reduces Blood Pressure And Prevents Endothelial Dysfunction And Oxidative Stress In Post-weaning Protein-restricted Rats.

Taurine is a sulfur-containing amino acid that exerts protective effects on vascular function and structure in several models of cardiovascular diseases through its antioxidant and anti-inflammatory properties. Early protein malnutrition reprograms the cardiovascular system and is linked to hypertension in adulthood. This study assessed the effects of taurine supplementation in vascular alterations induced by protein restriction in post-weaning rats. Weaned male Wistar rats were fed normal- (12%, NP) or low-protein (6%, LP) diets for 90 days. Half of the NP and LP rats concomitantly received 2.5% taurine supplementation in the drinking water (NPT and LPT, respectively). LP rats showed elevated systolic, diastolic and mean arterial blood pressure versus NP rats; taurine supplementation partially prevented this increase. There was a reduced relaxation response to acetylcholine in isolated thoracic aortic rings from the LP group that was reversed by superoxide dismutase (SOD) or apocynin incubation. Protein expression of p47phox NADPH oxidase subunit was enhanced, whereas extracellular (EC)-SOD and endothelial nitric oxide synthase phosphorylation at Ser 1177 (p-eNOS) were reduced in aortas from LP rats. Furthermore, ROS production was enhanced while acetylcholine-induced NO release was reduced in aortas from the LP group. Taurine supplementation improved the relaxation response to acetylcholine and eNOS-derived NO production, increased EC-SOD and p-eNOS protein expression, as well as reduced ROS generation and p47phox expression in the aortas from LPT rats. LP rats showed an increased aortic wall/lumen ratio and taurine prevented this remodeling through a reduction in wall media thickness. Our data indicate a protective role of taurine supplementation on the high blood pressure, endothelial dysfunction and vascular remodeling induced by post-weaning protein restriction. The beneficial vascular effect of taurine was associated with restoration of vascular redox homeostasis and improvement of NO bioavailability

Spironolactone prevents endothelial nitric oxide synthase uncoupling and vascular dysfunction induced by beta-adrenergic overstimulation: role of perivascular adipose tissue

Sustained stimulation of β-adrenoceptors (β-ARs) and activation of renin–angiotensin–aldosterone system are common features of cardiovascular diseases with rising sympathetic activation, including essential hypertension, myocardial infarction, and heart f683726735FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNQP - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO14/07947-611/15972-2SEM INFORMAÇÃOWe thank Dr Gisele K. Couto for help in diaminofluorescein (DAF-2) and hidroethidine (DHE) analysis. We also thank Dr Maria O. de Souza for a generous gift of ENaC antibodies. This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paul

Effect of post-weaning protein restriction and taurine supplementation on the morphometric parameters of rat aorta.

<p>Representative images of transversal aortic slices are shown in panel A. Aortic cross sectional area (CSA) (B) and wall/lumen ratio (C) were calculated in aortic slices of rats fed a normal-protein (NP) or low-protein (LP) diet, with or without taurine (T). Values represent the mean ± SEM (Number of animals in each group = 5–9). 2-way ANOVA: Figure 5B showed main effect of LP diet; Figure 5C showed significant interaction (LP diet x taurine). Bonferroni post-test (p<0.05): * <i>vs</i>. NP, ⁺<i>vs</i>. LP,^#<i>vs</i>. NPT.</p

Taurine prevented the alterations in p47^phox, EC-SOD and eNOS phosphorylation induced by low-protein diet.

<p>Protein expression of gp91^phox (A), p47^phox (B), EC-SOD (C), CuZn-SOD (D), Mn-SOD (E), catalase (F), glutathione peroxidase (GPx) (G), eNOS (H) and phosphorylated Ser1177 (p)eNOS (I) were analyzed by Western-blot in aorta from rats fed normal-protein (NP) or low-protein (LP), with or without taurine (T). α-actin content was used as internal control in each sample. Values represent the mean ± SEM (Number of animals in each group = 5–9). 2-way ANOVA:Figure 4B and 4C showed significant interaction (LP diet x taurine).Figure 4E showed main effect of LP diet;Figure 4I showed significant main effects of LP diet and taurine. Bonferroni post-test (p<0.05): * <i>vs</i>. NP, ⁺<i>vs</i>. LP, ^#<i>vs</i>. NPT.</p

Superoxide dismutase (SOD) and apocynin (Apo) restored the endothelium-dependent relaxation in aorta from low-protein-fed rats.

<p>Concentration-response curves to acetylcholine were obtained in aortas from rats fed an isocaloric normal-protein (NP) (A) or low-protein (LP) (B) diets supplemented with taurine (T) in drinking water (C, D). Values represent the mean ± SEM. The number of rats included in each group is indicated into parenthesis in the figure. 2-way ANOVA:Figure 2B showed significant main effects of SOD/Apo and acetylcholine. Bonferroni post-test (p<0.05): * <i>vs</i>. LP.</p

Taurine supplementation prevented the reduction in endothelium-dependent relaxation to acetylcholine induced by post-weaning protein restriction.

<p>Concentration-response curves to acetylcholine (A) and sodium nitroprusside (B) in aortas from rats fed an isocaloric normal-protein (NP) or low-protein (LP) diets without or with taurine (T). Relaxation responses are expressed as a percentage of serotonin-induced contraction. Values represent the mean ± SEM. The number of rats included in each group is indicated into parentheses in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105851#pone-0105851-g002" target="_blank">figure. 2</a>-way ANOVA:Figure 1A showed significant main effects of groups and acetylcholine;Figure 1B showed significant main effects of groups and sodium nitroprusside. Bonferroni post-test (p<0.05): * LP <i>vs</i>. NP, ⁺ LPT <i>vs</i>. LP, ^# LPT <i>vs</i>. NPT.</p