Phospholipid transfer protein activity is determined by type 2 diabetes mellitus and metabolic syndrome, and is positively associated with serum transaminases

BACKGROUND: The extent to which plasma phospholipid transfer protein (PLTP) activity is affected by type 2 diabetes mellitus (DM) and metabolic syndrome (MetS) is still unknown. PLTP is synthesized in the liver, and elevated serum transaminases are considered to predict nonalcoholic fatty liver disease (NAFLD). In this study, we examined the relationship between plasma PLTP activity and liver enzymes in subjects with and without DM and MetS. DESIGN: Plasma PLTP activity, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured in 71 subjects without DM or MetS, 21 without DM but with MetS, 26 with DM but without MetS and 55 with DM and MetS (WHO and NCEP-ATP III criteria). RESULTS: After controlling for age, sex and alcohol intake, PLTP activity was positively related to both MetS (P < 0.001) and DM (P = 0.001). Serum ALT (P = 0.006) and AST (P = 0.04) were both associated with MetS, but only ALT was associated with DM (P < 0.001). In multiple linear regression models, serum ALT and AST were positively and independently associated with PLTP activity (P < 0.01 for all), even when the presence of MetS and DM was taken into account, as well as after controlling for glycated haemoglobin (HbA(1c)), insulin resistance, triglycerides, free fatty acids (FFA), C-reactive protein (CRP), leptin and adiponectin. CONCLUSIONS: Plasma PLTP activity is determined by MetS and by diabetes per se. Serum transaminases are independently associated with PLTP activity. We suggest that this lipid transfer protein may be a marker for NAFLD