CHOLECALCIFEROL SUPPLEMENTATION AMELIORATES IMMUNE DYSFUNCTION IN OBESE HYPERTENSIVE PATIENTS

Abstract

Objective: Reduction of T regulatory cells (Treg) and upregulation of T helper 17 cells (Th17) contributes to obesity-associated hypertension. Since vitamin D is a modulator of the immune system, we hypothesized that supplementation with cholecalciferol in hypertensive patients may lead to a shift to a more anti-inflammatory immune status. Design and method: a 24-week randomized, open, parallel groups clinical trial including 36 patients with hypertension and overweight or obesity was conducted to evaluate the effects of cholecalciferol in peripheral Treg and Th17 cells. Patients were randomized to receive cholecalciferol according serum vitamin D (VD) levels plus usual therapy or usual therapy alone. The levels of Treg and Th17 on week 0 and 24 were obtained as well as body mass index (BMI), waist circumference, serum free VD, lipids, HbA1c, T helper 1 (Th1) cells and monocytes. Results: 18 men, average age 57.1 ± 5.5 years, BMI 34.5 ± 5.1 Kg/m2 and waist circumference 113.8 ± 10.7 cm. Sixteen patients (44.4%) had grade 1 obesity, seven (19.4%) grade 2 and six (1.6%) grade 3 obesity. The remaining had 7 had 25 < BMI < 30 Kg/m2. All patients were on antihypertensive drugs and mean value of vitamin D at the beginning of the trial was 15.7 ± 5.1 ng/mL. After supplementation serum VD levels rose to 26.9 ± 5.6 ng/mL (p = 0.000) and serum free VD levels from 5.2 ± 1.2 to 6.2 ± 3.3 ng/mL (p = 0.044). At 24 weeks the average ± SD values of the different cells between active and control groups were: Tregs 6.1 ± 1.5 and 6.8 ± 1.8; p = 0.226, respectively, Th17 cells 1.8 ± 0.8 and 2.7 ± 1.2; p = 0.017, Th1 cells 35.4 ± 18.1 and 30.3 ± 9.2; p = 0.299 and monocytes 5.7 ± 1.3 and 6.4 ± 2; p = 0.215. Conclusions: in overweight and obese hypertensive patients supplementation with cholecalciferol at regular doses reduces the levels of Th17 cells. Although statistically non-significant a decrease in monocytes was also observed. The reduction of Treg was unexpected, the significance of which should be clarified in future studies.