Placenta expression of vitamin D and related genes in pregnant women with gestational diabetes mellitus.

OBJECTIVES AND METHODS

A total of 41 GDM and 40 normal glucose tolerance subjects were recruited. Through detecting the level of Serum vitamin D with electrochemical luminescence and vitamin D receptor (VDR) with Enzyme-linked immunosorbent assay (ELISA) in maternal and cord blood, the expression leves of CYP24A1, CYP27B1, VDR protein and mRNA in placenta and umbilical cord with western blotting and RT-PCR, and the DNA methylation levels of CYP24A1 and CYP27B1 gene in placenta with methylation-specific PCR (MSP) and direct bisulfite sequencing (BSP) analysis to explore the potential role of the vitamin D and its related genes in gestational diabetes mellitus (GDM).

RESULTS

Serum vitamin D concentrations were significantly higher in normal pregnant than women with GDM in maternal blood (P < 0.01) and cord blood (P = 0.014). Compared to the control group, the expression levels of CYP24A1 protein (P < 0.01) and mRNA (P = 0.021) and VDR protein (P = 0.026) and mRNA (P = 0.023) in the GDM group were significantly higher in placenta and umbilical cord tissues (P = 0.015, P < 0.01, P = 0.028, P < 0.01, respectively), while that of CYP27B1 protein (P < 0.01) and mRNA (P = 0.042) was significantly lower (P = 0.022, P = 0.032, respectively). Moreover, partial DNA methylation of CYP24A1 and CYP27B1 genes was observed in both GDM and control groups.

CONCLUSIONS

Vitamin D deficiency participates in the pathogenesis of GDM, and changes in the expression of genes related to the vitamin D metabolic pathway are closely related to vitamin D levels in the pregnancy and fetus. However, DNA methylation of CYP24A1 and CYP27B1 might not be involved in the pathogenesis of GDM.