Disrupted placental vitamin D metabolism and calcium signaling in gestational diabetes and pre-eclampsia patients.

INTRODUCTION: Gestational diabetes (GDM) and pre-eclampsia (PE) represents the unrecognized risk factors for reduced bone content in neonates. The present study is planned to explore the components of vitamin D metabolism and calcium transport in placenta of GDM and PE cases and its effect on the neonatal bone mass determination using bone densitometry system. METHODS: We have collected serum and placenta tissues from GDM (n = 20), PE (n = 20), and healthy pregnancies (n = 20). In the present study, we found mRNA expression of oxidative stress markers, vitamin D metabolic components and calcium channels, calcium channel binding proteins, plasma membrane calcium ATPase, ATP synthase and Ca2+ release genes; Ryanodine receptors genes were assessed by quantitative real-time PCR (qRT-PCR) in placental tissue of GDM, PE, and healthy pregnancies. RESULTS: We observed high level of oxidative stress in both GDM and PE placenta compared to normal pregnancies. CYP2R1 and VDR mRNA expression was significantly downregulated and upregulation of CYP27B1 and CYP24A1 in GDM and PE compared with healthy cases. Similarly, calcium transporters were downregulated in GDM and PE placental tissues. In addition, CYP24A1, VDR, CaBP28K, TRPV5 and PMCA3 mRNA expression were correlated with BMC of neonates. DISCUSSION: Oxidative stress is probably relevant to disrupted vitamin D homeostasis and calcium transport in the placenta of GDM and PE cases. The altered regulatory mechanism of CYP24A1 and VDR could indicates more pronounced serum 25(OH)D reduction. Additionally, reduced BMC in the neonates of these cases might be as consequences of modified CYP24A1, VDR, CaBP28K, TRPV5 and PMCA3 mRNA expression.