The present study aimed to investigate the role of peptidase M20 domain containing 1 (PM20D1) in gestational diabetes mellitus (GDM).

Material and methods:
This observational study included 189 cases of GDM patients who came to our department between March 2018 and December 2019. Additionally, 100 healthy pregnant individuals who came to physical examination were included as healthy controls during the same period. Western blotting was used to determine the expression of PM20D1 at gestational age 24-28 weeks and gestational age 37–40 weeks. Serum inflammatory factors of C-reactive protein (CRP), interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, as well as leptin and adiponectin, were all measured by ELISA. The GDM related indices were also measured.

The expression of PM20D1 was markedly decreased in GDM patients compared with the healthy controls. Patients in the third trimester of pregnancy (gestational age 37–40 weeks) showed significantly lower expression of PM20D1 than patients in the second trimester of pregnancy (gestational age 24-28 weeks). Serum levels of CRP, IL-1β, IL-6, TNF-α and leptin were remarkably higher and levels of adiponectin were markedly lower in GDM patients at both the second and third trimester of pregnancy. Also, levels of CRP, IL-1β, IL-6, TNF-α and leptin in GDM patients were the highest at the third trimester of pregnancy. Pearson’s analysis showed that PM20D1 was negatively correlated with IL-1β, IL-6 and leptin and was positively correlated with adiponectin. At the second trimester of pregnancy, patients with lower expression of PM20D1 showed remarkably higher levels of HOMA-IR, fasting insulin, FBG, OGTT-1hPG, OGTT-2hPG, TG and LDL-C, and showed markedly lower levels of HDL-C. Down-regulated PM20D1 predicted poor pregnancy outcomes.

Reduced PM20D1 was associated with patients’ clinical outcomes and pregnancy outcomes in GDM.