Vitamin D Deficiency Reduces Vascular Reactivity of Coronary Arterioles in Male Rats

Abstract

Background: Vitamin D deficiency (VDD) may be considered an independent cardiovascular (CV) risk factor, and it is well known that CV risk is higher in males. Our goal was to investigate the pharmacological reactivity and receptor expression of intramural coronary artery segments of male rats in cases of different vitamin D supply. Methods: Four-week-old male Wistar rats were divided into a control group (n = 11) with optimal vitamin D supply (300 IU/kgbw/day) and a VDD group (n = 11, <0.5 IU/kgbw/day). After 8 weeks of treatment, intramural coronary artery segments were microprepared, their pharmacological reactivity was examined by in vitro microangiometry, and their receptor expression was investigated by immunohistochemistry. Results: Thromboxane A2 (TXA2)-agonist induced reduced vasoconstriction, testosterone (T) and 17-β-estradiol (E2) relaxations were significantly decreased, a significant decrease in thromboxane receptor (TP) expression was shown, and the reduction in estrogen receptor-α (ERα) expression was on the border of significance in the VDD group. Conclusions: VD-deficient male coronary arteries showed deteriorated pharmacological reactivity to TXA2 and sexual steroids (E2, T). Insufficient vasoconstrictor capacity was accompanied by decreased TP receptor expression, and vasodilator impairments were mainly functional. The decrease in vasoconstrictor and vasodilator responses results in narrowed adaptational range of coronaries, causing inadequate coronary perfusion that might contribute to the increased CV risk in VDD.

Vitamin-D Deficiency and Supplementation Altered the Network of the Coronary Arteries in a Rodent Model—In Situ Video Microscopic Technique

“…On the other hand, by our model an eight-week vitamin-D-free diet starting from weaning kept vitamin-D levels persistently low. The effects of vitamin-D deficiency on the histological characteristics of vascular cross-sections and the contraction and relaxation properties of coronaries [ 30 , 31 ] has already been demonstrated by our research group.…”

“…Arterial stiffness [ 25 ], altered endothelial function [ 26 , 27 ], increased atherogenesis [ 28 ], and changes in oxidative-stress tolerance [ 29 ] can all play a role in it. The topic of altered vascular contractility and relaxational ability associated with vitamin-D deficiency was studied by our research team in a rodent model in coronary arteries [ 30 , 31 ], cerebral arteries [ 32 , 33 ], renal arteries [ 34 ], carotid arteries [ 35 ] and the aorta [ 36 ].…”

Vitamin D Deficiency and Gender Alter Vasoconstrictor and Vasodilator Reactivity in Rat Carotid Artery

“…As the consequence of vitamin D deficiency, the myogenic tone of the mesenteric arteries doubles [ 33 ]. In coronary arteries of male animals, vitamin D deficiency decreased the vascular reactivity to thromboxane A2 and sexual steroids (estrogen and testosterone) [ 34 ]. On the other hand, in renal arteries, we saw increased Phe-induced contraction only in female, but not in male rats [ 17 , 26 ].…”

Effects of Gender and Vitamin D on Vascular Reactivity of the Carotid Artery on a Testosterone-Induced PCOS Model

“…In the literature, it is contradictory how vitamin D supplementation or deficiency affects estrogen receptor alpha expression. In thoracic aorta cells and coronary artery cells, estrogen receptor expression was decreased by vitamin D deficiency [25,49]. In another study, calcitriol did not significantly affect estrogen receptor α (ERα, ESR1) expression levels in the T47D cells of 3D cultured cells [50].…”