Objective: Intrahepatic cholestasis of pregnancy (ICP), the most common liver disease in pregnancy, is characterized by elevated serum total bile acid levels and pruritus. It has become clear that bile acids are no longer labeled as simple detergent-like molecules, but also represent complex hormonal metabolic regulators. ICP has also been associated with increased incidence rates of gestational diabetes mellitus. Irisin is a newly discovered myokine that is able to regulate glucose and lipid levels, thus improving insulin sensitivity. In this study, maternal serum irisin levels were analyzed in order to provide a new perspective on the pathogenesis of ICP.
Materials and methods: In this controlled cross-sectional study, 58 consecutive pregnant women with ICP (30 with mild and 28 with severe disease) and 30 healthy women with uncomplicated pregnancies (as the control group) were examined. The maternal irisin, fasting blood glucose, fasting insulin and homeostatic model assessment of insulin resistance levels of the two groups were compared.
Results: Serum irisin levels were significantly higher in the severe ICP group than in the mild ICP and control groups (p = 0.005 and p < 0.001, respectively). At the best cut-off level of 908.875 pg/ml, irisin accurately predicted ICP [AUC = 0.827 (95% CI: 0.745-0.909; p < 0.001)] with sensitivity and specificity rates of 72.5 and 86.8%, respectively. There was a significant negative correlation between irisin and fasting blood glucose levels (r = -0.399; p = 0.021).
Conclusion: The results of this study indicate that serum irisin levels were significantly higher in women with ICP compared to healthy pregnant controls. However, it is difficult to infer whether high irisin level is a cause or effect of ICP.
Keywords: Bile acid; FXR receptor; TGR5; insulin resistance; metabolic syndrome.