Vitamin D supplementation improves pathophysiology in a rat model of preeclampsia.

Deficiency of vitamin D (VD) is associated with preeclampsia (PE), a hypertensive disorder of pregnancy characterized by proinflammatory immune activation. We sought to determine whether VD supplementation would reduce the pathophysiology and hypertension associated with the reduced uterine perfusion pressure (RUPP) rat model of PE. Normal pregnant (NP) and RUPP rats were supplemented with VD2 or VD3 (270 IU and 15 IU/day, respectively) on gestation days 14-18 and mean arterial pressures (MAPs) measured on day 19. MAP increased in RUPP to 123 ± 2 mmHg compared with 102 ± 3 mmHg in NP and decreased to 113 ± 3 mmHg with VD2 and 115 ± 3 mmHg with VD3 in RUPP rats. Circulating CD4+ T cells increased in RUPP to 7.90 ± 1.36% lymphocytes compared with 2.04 ± 0.67% in NP but was lowered to 0.90 ± 0.19% with VD2 and 4.26 ± 1.55% with VD3 in RUPP rats. AT1-AA, measured by chronotropic assay, decreased from 19.5 ± 0.4 bpm in RUPPs to 8.3 ± 0.5 bpm with VD2 and to 15.4 ± 0.7 bpm with VD3. Renal cortex endothelin-1 (ET-1) expression was increased in RUPP rats (11.6 ± 2.1-fold change from NP) and decreased with both VD2 (3.3 ± 1.1-fold) and VD3 (3.1 ± 0.6-fold) supplementation in RUPP rats. Plasma-soluble FMS-like tyrosine kinase-1 (sFlt-1) was also reduced to 74.2 ± 6.6 pg/ml in VD2-treated and 91.0 ± 16.1 pg/ml in VD3-treated RUPP rats compared with 132.7 ± 19.9 pg/ml in RUPP rats. VD treatment reduced CD4+ T cells, AT1-AA, ET-1, sFlt-1, and blood pressure in the RUPP rat model of PE and could be an avenue to improve treatment of hypertension in response to placental ischemia.

Vitamin D Supplementation Suppresses Hypoxia-Stimulated Placental Cytokine Secretion, Hypertension and CD4+ T Cell Stimulation in Response to Placental Ischemia.

OBJECTIVE: To investigate a role of Vitamin D in the pathogenesis of preeclampsia (PE), and to discern any potential benefits of Vitamin D supplementation on hypertension in the RUPP rat model of PE. STUDY DESIGN: Blood and placentas from normal pregnancies (NP) and PE were collected following elective cesarean delivery without evidence of infection. Circulating Vitamin D was extracted by HPLC and measured via mass spectrometry. Media for placenta explants was supplemented with Vitamin D and exposed to hypoxic (1% O2) or normoxic (6% O2) conditions for 24 hours. ELISAs were performed on media and normalized to total protein to determine cytokine secretion. RUPP rats were supplemented with vitamin D by oral gavage, and blood pressure (MAP) and pup weights were measured in NP and RUPP rats with or without Vitamin D supplementation. Flow cytometry was used to evaluate CD4+ Tcells in control RUPP rats and RUPP rats treated with Vitamin D. RESULTS: Inflammatory cytokine secretion was higher (p<0.05) while the anti-inflammatory cytokine, IL-10, was significantly lower in the media of PE placentas compared to NP (p=0.005). Vitamin D supplementation decreased hypoxia stimulated pro-inflammatory cytokine secretion (p=0.003) in the media of PE placentas. Vitamin D decreased MAP and circulating CD4+ T cells in the RUPP rat model of PE (p<0.05). CONCLUSION: Vitamin D supplementation may be useful in the treatment or prevention of hypertensive disorders in pregnancy.