Investigation of serum isthmin 1 concentration in pregnant women diagnosed with gestational diabetes mellitus; a case-control study

Objective: Isthmin 1 (ISM1) is an adipokine that improves hyperglycemia by increasing glucose uptake in a non-insulin-dependent manner. Studies have shown that ISM is associated with the development of type 2 diabetes mellitus. Based on this, we aimed to investigate serum ISM1 concentrations of pregnant women with gestational diabetes mellitus (GDM).

Methods: This case-control study was conducted with 80 pregnant women who applied to the Gynecology and Obstetrics Clinic of Umraniye Training and Research Hospital between April 2022 and November 2022. While 40 pregnant women diagnosed with GDM according to 75 g OGTT results formed the GDM group, 40 pregnant women with normal OGTT results formed the control group. The two groups were compared in terms of serum ISM1 concentrations.

Results: Both groups were similar in terms of demographic characteristics (p > 0.05). Fasting blood glucose levels, 1st-hour and 2nd-hour blood glucose levels in 75 g OGTT, fasting insulin levels, and HOMA-IR were significantly higher in the GDM group (p > 0.05, for each). Both groups were similar in terms of maternal waist circumference, periumbilical, and epigastric subcutaneous adipose tissue thickness (p > 0.05, for each).Both groups were similar in terms of the gestational week at blood sampling for ISM1 (p = 0.253). The median maternal serum ISM1 concentration was found to be 3243.94 pg/ml in the GDM group, while it was determined as 2785.29 pg/ml in the non-GDM group (p = 0.026).ROC analysis was performed to determine the value of maternal serum ISM1 concentration in predicting GDM. AUC analysis of maternal serum ISM1 for estimation of GDM was 0.645 (p = 0.026, 95% CI = 0.523 - 0.766). The optimal threshold value for maternal serum ISM1 concentration was determined as 3124.41 pg/ml with 62.5% sensitivity and 62.5% specificity.

Conclusions: Serum ISM1 concentrations were found to be higher in pregnant women with GDM than in healthy controls. Whether or how ISM1 participates in the pathophysiology of GDM remains to be investigated.