Anticontractile effects of perivascular adipose tissue are increased in obese hypertensive rats

Abstract

Perivascular adipose tissue (PVAT) reduces vascular contractile responses in normal conditions. Both hypertension and obesity decrease PVAT anticontractile effects despite having opposite effects on PVAT mass. We hypothesized that PVAT anticontractile effects would be reduced in obese hypertensive rats. Contractile responses in the presence and absence of PVAT were measured in aorta and resistance mesenteric arteries (MA) from control and AngHFHS obese hypertensive rats. Blood pressure and visceral adiposity were significantly increased in AngHFHS compared to control rats. In the absence of PVAT, contraction to phenylephrine (PE) and serotonin (5‐HT) was increased in both aorta and MA of AngHFHS rats. PVAT reduced contractile responses to PE, 5‐HT and ET‐1 in both aorta and MA, however this anticontractile effect was augmented in vessels from AngHFHS rats (anticontractile effect as % reduction in max contraction, con: PE=8.35, 5‐HT=9.53, ET‐1=14.43 vs AngHFHS: PE=36.06, 5‐HT=18.20, ET‐1=39.77). Incubation with DL‐PPG, an inhibitor of cystathionine gamma lyase, partially reverted maximal PE‐induced contraction in PVAT‐intact aorta from AngHFHS, but not control rats. Contrary to our hypothesis, these data suggest that anticontractile function of PVAT is increased in obese hypertensive rats and this may be mediated by an upregulation in the H2S‐producing activity of CSE in the PVAT of these rats.