The Role of Osteocalcin in Placenta Function in Gestational Diabetes Mellitus

Abstract Background: Evidence for osteocalcin role in glucose and energy metabolism is increasing. However, little is known about osteocalcin function in gestational diabetes mellitus. The aim of this study is to examine the associations between osteocalcin and gestational diabetes mellitus. Method: 36 patients with gestational diabetes mellitus and 40 normal glucose tolerance controls were recruited in the Maternal and Child Health Hospital Guangxi Zhuang Autonomous Region from May to August 2018. Total osteocalcin and biochemical indexes of maternal serum and umbilical vein serum were analyzed. Transcriptome of placenta were sequenced. Human trophoblast JAR cells were used for evaluated the affection of osteocalcin on trophoblast In vitro. There were no significant differences with maternal serum total osteocalcin levels between gestational diabetes mellitus and normal glucose tolerance groups. The gestational diabetes mellitus group has lower umbilical vein serum total osteocalcin (51.46 ng/mL ± 24.29 Vs 67.00 ng/mL ± 25.33, P = 0.008 ), lower adiponectin (1099.72 μg/L ± 102.65 Vs 1235.85 μg/L ± 94.63, P < 0.001), higher leptin (7.41 μg/L ± 0.28 Vs 6.02 μg/L ± 0.31, P ＜ 0.001). A significant relationship existed between umbilical vein serum total osteocalcin levels and leptin (r = -0.456, P = 0.007). Osteocalcin promote JAR trophoblast cells proliferation and HCG synthesis. 36 correlated gene modules of placental transcriptome were identified through weighted gene co-expression network analysis, 2 of them were associated with osteocalcin. Conclusion: lower osteocalcin in umbilical vein serum is associated with gestational diabetes mellitus, osteocalcin may regulate placenta function via adiponectin.