Empagliflozin and Hepatic Glucose Metabolism

Purpose/Objectives: To investigate the effect of empagliflozin, an SGLT2 inhibitor on hepatic glucose production and the role of autonomic nervous system in mediating the increase in hepatic glucose production in response glucosuria Research Design/Plan: the role of autonomic nervous system in the increase in hepatic glucose production caused by empagliflozin will be examined with norepinephrine (NE) turnover in two protocols. The first protocol is cross sectional, in which 36 T2DM patients will receive hepatic glucose production (HGP) and NE turnover will be measured before and after empagliflozin or placebo administration. In protocol 2, diabetic and non-diabetic subjects will receive baseline HGP, NE turnover, hepatic glucose uptake (HGU) and liver fat measurement before at 2 days after the start and 12 weeks after empagliflozin or placebo treatment. Methods: the following techniques will be employed (1) Measurement of hepatic glucose production with 3H-glucose infusion, with and without glucose clamp, (2) substrate oxidation with indirect calorimetry and plasma ketone/lactate/insulin/glucagon concentrations; (3) Measurement of HGU with Oral-IV double tracer infusion; (4) Measurement of whole body norepinephrine turnover with 3H-norepinephrine infusion; (5) Measurement of heart rate variability; (6) Measurement of liver fat content with 1H-MRS Clinical Relevance: The results of the present studies will help identify the mechanism responsible for the increase in HGP caused by empagliflozin and the increase in ketone production. The first action of the drug ameliorates its clinical efficacy while the second increases the risk of adverse events (ketoacidosis). Identifying the mechanisms underlying these actions will help developing therapeutic strategies which increase the drug clinical efficacy and mitigates its adverse events.