Type 2 diabetes (T2DM) associated with non-alcoholic fatty liver disease (NAFLD) increases cardiovascular risk. Complex and subtle connections are established between hepatic dysfunction and adipose tissue hyperactivity. This relationship is mediated by insulin resistance, dyslipidemia and inflammation. Recently incretins have been involved in this connection including GLP-1 (glucagon-like peptide-1). The aim of this study is to establish interactions between the GLP-1 plasma levels and metabolic syndrome clusters and adipocytokines profile (leptin, adiponectin, resistin, TNFα and IL-6) in diabetic subjects with or without NAFLD. The study was undertaken on 320 adult subjects divided into four groups: NAFLD, DT2, NAFLD+DT2 and control. In all subjects, the metabolic syndrome clusters was investigated according to the NCEP/ATPIII criteria. Insulin resistance was evaluated by the Homa-IR model. The metabolic parameters were determined on Cobas® automated biochemical analysis. The adipocytokines are determined by immunoassay method on Elisa human reader - Biotek ELX 800. The NAFLD has been confirmed by abdominal ultrasound and by histology. Feeding and fasting plasma GLP-1 was assessed by Elisa method. The data revealed that insulin resistance (Homa-IR) is present in all groups. Homa-IR is negatively associated with plasma GLP-1 depletion in the NAFLD, DT2 and NAFLD+DT2 groups. Adiponectin levels are decreased in all groups as for GLP-1. At the opposite, leptin, resistin, TNFα and IL-6 levels show an inverse correlation with GLP-1. This study suggests that plasma GLP-1 can be considered as a transition and evolution biomarker between NAFLD and T2D. GLP-1 accurately reflects metabolic and inflammatory status, both in subjects with NAFLD only or with T2D only, before the diabetes - steatosis stage.
Keywords: NAFLD; adipocytokines; glucagon-like peptide-1; insulin resistance; metabolic syndrome; type 2 diabetes.