The relationship between irisin and insulin resistance in patients with gestational diabetes

Diabetes mellitus is a chronic disorder of carbohydrate metabolism characterized by hyperglycemia, and resulting from defects in insulin secretion, insulin action, or both. Gestational diabetes mellitus is defined as glucose intolerance that occurs with pregnancy or is first recognized during pregnancy. Women with gestational diabetes are thought to constitute future diabetes-risk population. In diabetes pathophysiology, limited information is available regarding the effects of muscle tissue particularly on insulin resistance, as well as the molecules establishing communications between muscle tissue and tissues like liver, adipose tissue, and pancreas. Recently, the "irisin" peptide which is released by muscle cells, and acts as a messenger between muscle and adipose tissues has been shown to play a major role in the insulin resistance and in the regulation of energy metabolism. In this study, it was aimed to evaluate the serum levels of the irisin in gestational diabetes cases, which are most likely to have insulin resistance. This study included a total of 102 people of the similar age group; 30 pregnant women with gestational diabetes, 31 healthy pregnant women, and 41 healthy controls. In the comparison of the study subjects for BMI (GDM 27,92±6,52; Healthy Pregnant 25,04±4,59; Control 23,03±3,53; p<0,01), HOMA IR (GDM 2,85±1,79; Healthy Pregnant 1,84±1,29; Control 1,44±0,51 p<0,01) and serum irisin levels (GDM 119,10±50,99; Healthy Pregnant 87,68±55,63; Control 76,27±27,32; p<0,01), BMI, HOMA-IR and serum irisin levels were found to be statistically significantly higher in the GDM group BMI, HOMA-IR ve serum irisin than the other two groups. In healthy pregnants, PBG (GDM 83,50±15,33; Healthy Pregnant 71,81±7,39; Control 83,61±6,78; p<0,01) and HbA1c (GDM 5,44±0,44; Healthy Pregnant 5,04±0,23; Control 5,27±0,26; p<0,01) values were measured statistically significantly lower compared to other two groups. The comparison of each three groups in terms of insulin levels revealed significantly lower insulin levels in the control group compared to the GDM and healthy pregnant groups (GDM 13,51±7,33; Healthy Pregnant 10,02±6,05; Control 6,96±2,31; p<0,01). In the correlation analysis, a significant positive relationship was found between serum irisin levels and HbA1c (r = 0.3, p = 0.0027), and BMI (r = 0.26, p <0.01) . This is the first study examining the association between insulin resistance in gestational diabetes and the irisin molecule, which was recently identified and shown to cause insulin resistance at low doses. However, contrary to the expectations, serum levels of the irisin were found higher in our gestational diabetes cases. This suggests that, similar to the changes in insulin receptor and postreceptor signalization in gestational diabetes, the irisin protein may be deactivated at receptor levels in pregnants. Further studies are required to be conducted to understand the role of the irisin molecule in this process.