scholarly journals Effect of Perivascular Adipose Tissue on Arterial Adrenergic Contractions in Normotensive and Hypertensive Rats With High Fructose Intake

2017 ◽  
pp. S537-S544
Author(s):  
A. ZEMANČÍKOVÁ ◽  
J. TÖRÖK

The aim of this study was to investigate the effect of high fructose intake associated with moderate increase in adiposity on rat arterial adrenergic responses and their modulation by perivascular adipose tissue (PVAT). After eight-week-lasting substitution of drinking water with 10 % fructose solution in adult normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR), their systolic blood pressure, plasma triglycerides, and relative liver weight were elevated when compared to their respective control groups. Moreover, in SHR, body weight and relative heart weight were increased after treatment with fructose. In superior mesenteric arteries, PVAT exerted inhibitory influence on adrenergic contractile responses and this effect was markedly stronger in control WKY than in SHR. In fructose-administered WKY, arterial adrenergic contractions were substantially reduced in comparison with the control group; this was caused mainly by enhancement of anticontractile action of PVAT. The diminution of the mesenteric arterial contractions was not observed after fructose treatment in SHR. We conclude that the increase in body adiposity due to fructose overfeeding in rats might have pro-hypertensive effect. However, in WKY it might cause PVAT-dependent and independent reduction in arterial contractile responses to adrenergic stimuli, which could attenuate the pathological elevation in vascular tone.

2016 ◽  
pp. S391-S399 ◽  
Author(s):  
J. TÖRÖK ◽  
A. ZEMANČÍKOVÁ ◽  
Z. KOCIANOVÁ

The inhibitory action of perivascular adipose tissue (PVAT) in modulation of arterial contraction has been recently recognized and contrasted with the prohypertensive effect of obesity in humans. In this study we demonstrated that PVAT might have opposing effect on sympatho-adrenergic contractions in different rat conduit arteries. In superior mesenteric artery isolated from normotensive Wistar-Kyoto rats (WKY), PVAT exhibited inhibitory influence on the contractions to exogenous noradrenaline as well as to endogenous noradrenaline released from arterial sympathetic nerves during transmural electrical stimulation or after application of tyramine. In contrast, the abdominal aorta with intact PVAT responded with larger contractions to transmural electrical stimulation and tyramine when compared to the aorta after removing PVAT; the responses to noradrenaline were similar in both. This indicates that PVAT may contain additional sources of endogenous noradrenaline which could be responsible for the main difference in the modulatory effect of PVAT on adrenergic contractions between abdominal aortas and superior mesenteric arteries. In spontaneously hypertensive rats (SHR), the anticontractile effect of PVAT in mesenteric arteries was reduced, and the removal of PVAT completely eliminated the difference in the dose-response curves to exogenous noradrenaline between SHR and WKY. These results suggest that in mesenteric artery isolated from SHR, the impaired anticontractile influence of PVAT might significantly contribute to its increased sensitivity to adrenergic stimuli.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Anna Zemančíková ◽  
Jozef Török

Perivascular adipose tissue (PVAT) and its vasomodulatory effects play an important role in the physiology and pathophysiology of blood vessels. Alterations in PVAT associated with reduction in its anticontractile influence are proven to contribute to vascular dysfunction in hypertension. The aim of this study was to examine whether the changes in PVAT properties could participate in progression of vascular abnormalities in developing spontaneously hypertensive rats (SHR). Normotensive Wistar-Kyoto (WKY) rats and SHR, both in 5th and in 12th week of age, were used. Systolic blood pressure was similar between WKY rats and SHR in 5th week of age; however, in 12th week, it was significantly increased in SHR comparing to WKY rats. The amount of retroperitoneal fat was higher in WKY rats in both age groups, whereas body weight was higher in WKY rats only in 12th week, when compared to age-matched SHR. From isolated superior mesenteric arteries, two ring preparations were prepared for isometric tension recording, one with PVAT intact and other with PVAT removed. In WKY rats as well as in SHR, arterial contractile responses to noradrenaline, applied cumulatively on rings, were significantly inhibited in the presence of intact PVAT. In both age groups, anticontractile effect of PVAT was higher in WKY rats than in SHR. Neurogenic contractions, induced by electrical stimulation of perivascular sympathoadrenergic nerves, were significantly attenuated in the presence of PVAT in WKY mesenteric arteries from both age groups; however, in arteries from SHR, intact PVAT had no influence on this type of contractile responses. The results suggest that in SHR impairment of anticontractile effect of PVAT precedes hypertension and might contribute to its development.


Biomedicines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1552
Author(s):  
Jozef Torok ◽  
Anna Zemancikova ◽  
Zuzana Valaskova ◽  
Peter Balis

The aim of the current study was to evaluate the influence of a high-fat diet and its combination with high-fructose intake on young normotensive rats, with focus on the modulatory effect of perivascular adipose tissue (PVAT) on the reactivity of isolated arteries. Six-week-old Wistar–Kyoto rats were treated for 8 weeks with a control diet (10% fat), a high-fat diet (HFD; 45% fat), or a combination of the HFD with a 10% solution of fructose. Contractile and relaxant responses of isolated rat arteries, with preserved and removed PVAT for selected vasoactive stimuli, were recorded isometrically by a force displacement transducer. The results demonstrated that, in young rats, eight weeks of the HFD might lead to body fat accumulation and early excitation of the cardiovascular sympathetic nervous system, as shown by increased heart rate and enhanced arterial contractile responses induced by endogenous noradrenaline released from perivascular sympathetic nerves. The addition of high-fructose intake deteriorated this state by impairment of arterial relaxation and resulted in mild elevation of systolic blood pressure; however, the increase in arterial neurogenic contractions was not detected. The diet-induced alterations in isolated arteries were observed only in the presence of PVAT, indicating that this structure is important in initiation of early vascular changes during the development of metabolic syndrome.


2009 ◽  
Vol 87 (11) ◽  
pp. 944-953 ◽  
Author(s):  
Robert M.K.W. Lee ◽  
Lili Ding ◽  
Chao Lu ◽  
Li-Ying Su ◽  
Yu-Jing Gao

We studied the role of perivascular adipose tissue (PVAT) in the control of vascular function in an in vivo experimental model of hypertension produced by angiotensin II infusion by osmotic minipump in adult male Wistar rats. Two weeks after infusion with angiotensin II, blood pressure in treated rats was significantly elevated but heart rate was reduced compared with control rats infused with physiological saline. Contraction of aorta from the 2 groups of rats in response to phenylephrine or serotonin was significantly attenuated by the presence of PVAT in both the presence and absence of endothelium. This attenuation effect on contraction to phenylephrine was higher, however, in vessels from control rats than in vessels from hypertensive rats in the absence of endothelium. In the mesenteric resistance arteries, lumen diameter was larger in both hypertensive and control vessels with intact PVAT than in vessels with PVAT removed. The medial wall was thicker in arteries from hypertensive rats. The presence of PVAT potentiated the contraction induced by KCl in mesenteric arteries from control rats, but not in hypertensive rats. PVAT also attenuated the contraction of mesenteric arteries in response to phenylephrine or serotonin in both hypertensive and control groups. Mesenteric arteries from hypertensive rats were more responsive to stimulation by serotonin than those from control rats. We conclude that the increased blood pressure of Wistar rats that occurred after infusion with angiotensin II was associated with changes in the functions of PVAT in the aorta and mesenteric arteries and in the structure and function of resistance arteries.


2013 ◽  
Vol 304 (6) ◽  
pp. H786-H795 ◽  
Author(s):  
Fiona M. Lynch ◽  
Sarah B. Withers ◽  
Zhihong Yao ◽  
Matthias E. Werner ◽  
Gill Edwards ◽  
...  

This study aims to identify the potential mechanisms by which perivascular adipose tissue (PVAT) reduces tone in small arteries. Small mesenteric arteries from wild-type and large-conductance Ca2+-activated K+ (BKCa) channel knockout mice were mounted on a wire myograph in the presence and absence of PVAT, and contractile responses to norepinephrine were assessed. Electrophysiology studies were performed in isolated vessels to measure changes in membrane potential produced by adiponectin. Contractile responses from wild-type mouse small arteries were significantly reduced in the presence of PVAT. This was not observed in the presence of a BKCa channel inhibitor or with nitric oxide synthase (NOS) inhibition or in BKCa or adiponectin knockout mice. Solution transfer experiments demonstrated the presence of an anticontractile factor released from PVAT. Adiponectin-induced vasorelaxation and hyperpolarization in wild-type arteries were not evident in the absence of or after inhibition of BKCa channels. PVAT from BKCa or adiponectin knockout mice failed to elicit an anticontractile response in wild-type arteries. PVAT releases adiponectin, which is an anticontractile factor. Its effect on vascular tone is mediated by activation of BKCa channels on vascular smooth muscle cells and adipocytes and by endothelial mechanisms.


Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Theodora Szasz ◽  
Takayuki Matsumoto ◽  
Camilla F Wenceslau ◽  
R Clinton Webb

In normal conditions, perivascular adipose tissue (PVAT) decreases contractile responses non-specifically in various vascular beds. This anti-contractile effect of PVAT is reduced in metabolic diseases and hypertension. The β3 adrenergic receptor (β3AR) is a G protein-coupled receptor expressed in adipocytes and involved in lipolysis and thermoregulation. We have previously demonstrated that chronic systemic infusion with a β3AR agonist induces white-to-brown adipose tissue remodeling and enhanced anti-contractile effects of PVAT via activation of cystathionine gamma lyase, enzyme involved in hydrogen sulfide synthesis. We hypothesized that the β3AR is directly mediating release of PVAT relaxing factors. Endothelium-intact mesenteric resistance arteries from adult male Wistar rats were used to measure contractile responses in the presence and absence of PVAT. In the absence of PVAT, the β3AR agonist CL316243 (1 nM-10 μM) did not directly induce relaxation of U46619-contracted arteries. In control conditions, norepinephrine (NE)-induced contraction was significantly reduced in the presence of PVAT. In contrast, incubation with the selective β3AR antagonist L-748337 (100 nM) led to a significant increase in NE-induced contraction in PVAT-intact arteries, while no change was observed in the absence of PVAT (figure). These data suggest that β3AR mediates the anti-contractile effect of PVAT on NE-induced contraction in resistance mesenteric arteries. Considering the structural and functional alterations of PVAT in hypertension, future studies may reveal a potential novel therapeutic approach via targeting of the PVAT β3AR pathway.


2018 ◽  
Vol 20 (1) ◽  
pp. 106 ◽  
Author(s):  
Satomi Kagota ◽  
Kana Maruyama-Fumoto ◽  
Saki Iwata ◽  
Miho Shimari ◽  
Shiori Koyanagi ◽  
...  

Perivascular adipose tissue (PVAT) can regulate vascular tone. In mesenteric arteries of SHRSP.Z-Leprfa/IzmDmcr rats (SHRSP.ZF) with metabolic syndrome, vascular dysfunction is compensated by PVAT-dependent mechanisms that disappear with increasing age. In this study, we investigated the mechanisms of the age-related changes and responsible factor(s) involved in the enhancing effects of mesenteric arterial PVAT in SHRSP.ZF. Acetylcholine- and sodium nitroprusside-induced relaxations of isolated arteries were greater with PVAT than without PVAT at 17 and 20 weeks of age (wks), and as expected, this enhancement by the presence of PVAT disappeared at 23 wks. PVAT mRNA levels of angiotensin II type 1 (AT1) receptor-associated protein was less and AT1 receptor was unchanged at 23 wks when compared to 20 wks. At 20 wks, the enhanced acetylcholine-induced relaxation by the presence of PVAT was inhibited by N-acetyl-l-cysteine (NAC). Acetylcholine-induced relaxation of arteries without PVAT was increased in the presence of exogenously added apelin. PVAT mRNA level of apelin was higher in SHRSP.ZF than in control Wistar-Kyoto rats, and the level was decreased with aging. These results suggest that AT1 receptor activation in PVAT, and changes in the regulation of apelin and a NAC-sensitive factor are related to the age-dependent deterioration of the vasodilation enhancing effects of mesenteric arterial PVAT in SHRSP.ZF.


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