THE CHANGES IN VITAMIN D AND IONIZED CALCIUM LEVELS IN PATIENTS WITH ESSENTIAL HYPERTENSION DEPENDING ON THE AGT GENE (RS699) POLYMORPHISM

Abstract

Objective: To analyze the vitamin D and ionized calcium levels in patients with essential arterial hypertension (EAH) depending on AGT gene (rs699) polymorphism. Design and method: 72 subjects with EAH and target-organ damaging (2nd stage), moderate, high or very high cardiovascular risk were involved in the case-control study. Among them, 70.84% (51) females and 29.16% (21) males, mean age 59.87 ± 7.98 y o. Control group consisted of forty-eight practically healthy individuals with relevant age (49.13 ± 6.28 y o) and sex distribution (62% females, 38% males). AGT (rs699) gene polymorphism was examined by real-time polymerase chain reaction. Intact parathyroid hormone (intact PTH) and vitamin 25 (OH) D levels in blood serum were determined by chemiluminescence immunoassay (MAGLUMI). Results: The concentration of ionized Ca2+ in blood in patients with TT-genotype of the AGT gene (rs699) is extremely likely to be lower than in CC-genotype carriers (p = 0.051). In addition, we found that in men with EAH who were T-allele carriers (TT- and TC-genotypes) the level of ionized Ca2+ in blood is probably lower than in women of the corresponding genotypes: 1.14 ± 0.01 vs. 1.17 ± 0.015 mmol/l (p < 0,05) and 1,14 ± 0,01 vs. 1,19 ± 0,02 mmol/l (p < 0,05), respectively. Whereas in the CC-genotype carriers, on the contrary, the level of ionized Ca2+ was higher in men than in women: 1.18 ± 0.01 vs. 1.14 ± 0.015 mmol/l (p = 0.014). Against this background, the level of vitamin 25 (OH) D in the blood of the AGT gene (rs699) TT-genotype carriers in patients with EAH became lower than in those with the CC-genotype by 16.24% (p = 0.049), and the concentration of intact PTH on the contrary, higher, but incredibly - by 7.30%, which is, in our opinion, a manifestation of compensatory-adaptive reactions of the body aimed at maintaining hormonal-metabolic homeostasis and calcium-phosphorus ion balance. In the control group, the difference in intact PTH was statistically significant, being higher in TT-carriers - by 28.89% and 21.26% (PTT < 0.05). Conclusions: One-way ANOVA analysis of variance did not confirm the association of the AGT gene (rs699) with the vitamin D and ionized calcium levels.