The Role of Perivascular Adipose Tissue in Early Changes in Arterial Function during High-Fat Diet and Its Combination with High-Fructose Intake in Rats

Jozef Torok,Zuzana Valaskova,Peter Balis,Anna Zemancikova

doi:10.3390/biomedicines9111552

Abstract

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.

Highlights

Metabolic syndrome refers to the co-occurrence of several known cardiovascular risk factors, including central adiposity, hypertension, dyslipidemia, and impaired glucose metabolism
Group compared to the control rats (256.4 ± 7.2 KJ vs. 213.2 ± 6.2 KJ per rat, respectively; p < 0.001), and significantly higher in the group treated with the high-fat diet (HFD) and 10% fructose together (299.2 ± 11.8 KJ per rat) compared to the group fed with the HFD alone (p < 0.01)
The differences in arterial reactivity observed in this study after the HFD or combinedfructose treatment were associated with the presence of intact perivascular fat, while the arteries cleaned from perivascular adipose tissue (PVAT) showed similar functional properties when compared to PVAT(−) arterial preparations obtained from control rats

Summary

Introduction

Metabolic syndrome refers to the co-occurrence of several known cardiovascular risk factors, including central adiposity, hypertension, dyslipidemia, and impaired glucose metabolism. It has been associated with an increase in the incidence of coronary heart disease, stroke, and cardiovascular mortality [1,2]. The subjects who start to manifest metabolic syndrome in childhood, or in adolescence, will be exposed for decades to potent vascular risk factors, which suggests a high propensity for serious cardiovascular complications later in life [4,5]. It was suggested that the rat model displaying the closest criteria to human metabolic syndrome was induced by a high-carbohydrate, high-fat diet [6].

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