Gestational diabetes mellitus (GDM) is characterized by maternal hyperglycemia and insulin resistance that develops during pregnancy. Altered secretion of adipokines that modulate insulin action during pregnancy has been implicated in GDM pathogenesis. FABP4 is an adipokine with an important role in promoting insulin resistance in various animal models. In humans, FABP4 was suggested to regulate systemic metabolism. Although elevated levels of circulating FABP4 were demonstrated in GDM, its differential contribution to GDM pathophysiology is unclear. In this study, we aimed to determine the tissue source of elevated circulating FABP4 levels and to assess FABP4 differential contribution in promoting hepatic glucose production in GDM. We included 71 pregnant women defined as normal glucose tolerant (NGT) and 31 diagnosed with GDM. Maternal level of FABP4 before delivery was measured using ELISA. FABP4 circulating levels were increased in GDM compared to NGT (14.1 IQR: 11.5-21.4 ng/ml vs.10.3 IQR: 6.6-12.4 ng/ml, respectively, p=0.0014), with a rapid post-partum decline in FABP4 levels observed in both groups. Using biopsies of placenta, sub-cutaneous (sWAT) and visceral (vWAT) adipose tissues, we observed that FABP4 is secreted from these tissues during pregnancy. FABP4 secretion from vWAT of GDM women was ? 2 fold higher than that of NGT women. Depletion of FABP4 from vWAT conditioned media of NGT or GDM women using monoclonal antibodies, significantly suppressed glucose production in primary hepatocytes by ? 20% and ? 36%, respectively (p<0.05). Taken together, our data highlight the importance of FABP4 in the pathophysiology of enhanced hepatic glucose production in GDM.
R. Madah: None. I. Ron Ronen: None. M. Rathaus: None. R. Zemet: None. S. Amazaki Tovi: None. A. Tirosh: Advisory Panel; Self; Abbott, AstraZeneca, Merck Sharp & Dohme Corp., Novo Nordisk A/S, Sanofi-Aventis. Consultant; Self; DreaMed Diabetes. Research Support; Self; Medtronic.
Israeli Diabetes Association