Role of Perivascular Adipose Tissue and Exercise on Arterial Function with Obesity

Exercise attenuates high-fat diet-induced PVAT dysfunction through improved inflammatory response and BMP4-regulated adipose tissue browning

Background

Perivascular adipose tissue (PVAT) dysfunction impairs vascular homeostasis. Impaired inflammation and bone morphogenetic protein-4 (BMP4) signaling are involved in thoracic PVAT dysfunction by regulating adipokine secretion and adipocyte phenotype transformation. We investigated whether aerobic exercise training could ameliorate high-fat diet (HFD)-induced PVAT dysfunction via improved inflammatory response and BMP4-mediated signaling pathways.

Methods

Sprague-Dawley rats (n = 24) were divided into three groups, namely control, high-fat diet (HFD), and HFD plus exercise (HEx). After a 6-week intervention, PVAT functional efficiency and changes in inflammatory biomarkers (circulating concentrations in blood and mRNA expressions in thoracic PVAT) were assessed.

Results

Chronic HFD feeding caused obesity and dyslipidemia in rats. HFD decreased the relaxation response of PVAT-containing vascular rings and impaired PVAT-regulated vasodilatation. However, exercise training effectively reversed these diet-induced pathological changes to PVAT. This was accompanied by significantly (p < 0.05) restoring the morphological structure and the decreased lipid droplet size in PVAT. Furthermore, HFD-induced impaired inflammatory response (both in circulation and PVAT) was notably ameliorated by exercise training (p < 0.05). Specifically, exercise training substantially reversed HFD-induced WAT-like characteristics to BAT-like characteristics as evidenced by increased UCP1 and decreased FABP4 protein levels in PVAT against HFD. Exercise training promoted transcriptional activation of BMP4 and associated signaling molecules (p38/MAPK, ATF2, PGC1α, and Smad5) that are involved in browning of adipose tissue. In conjunction with gene expressions, exercise training increased BMP4 protein content and activated downstream cascades, represented by upregulated p38/MAPK and PGC1α proteins in PVAT.

Conclusion

Regular exercise training can reverse HFD-induced obesity, dyslipidemia, and thoracic PVAT dysfunction in rats. The browning of adipose tissue through exercise appears to be modulated through improved inflammatory response and/or BMP4-mediated signaling cascades in obese rats.

Perivascular adipose tissue-mediated arterial stiffening in aging and disease: An emerging translational therapeutic target?

Cardiovascular diseases (CVD) are the leading cause of mortality in modernized societies. Arterial stiffening with aging and disease is a key pathological event leading to increased CVD morbidity and mortality. Perivascular adipose tissue (PVAT) is a fat depot not widely studied yet has direct and profound effects on arterial stiffening. Identifying PVAT as a novel therapeutic target to lower arterial stiffness and thereby CVD risk has potentially important clinical ramifications. Thus, herein, we will overview the current preclinical evidence and the associated mechanisms for PVAT to promote arterial stiffness with aging and other disease conditions. We will also discuss viable translational lifestyle and pharmacological interventions for altering PVAT function that may de-stiffen arteries. Last, the translational potential for PVAT as a therapeutic target to lower arterial stiffness and CVD risk for clinical populations will be discussed.

The Role of Adipokines in Cardiovascular Pathology

The recent decades saw a steady growth of obesity incidence worldwide. Obesity is an independent risk factor for cardiovascular diseases (CVDs) and type 2 diabetes mellitus and is also associated with a shorter life expectancy. Not only hemodynamic but also hormone metabolic processes, arising from excessive accumulation of adipose tissue in human body, underlie the development of CVDs. Adipose tissue has now been proved to be a hormone-active substrate. Studies of the influence of adipokines will bring us closer to understanding cardiovascular pathogenesis and help personalize prophylactic strategies.