Attenuated suppression of lipolysis explains the increases in triglyceride secretion and concentration associated with basal insulin peglispro relative to insulin glargine treatment in patients with type 1 diabetes.

ABSTRACT

AIMS: To test the hypothesis that, as well as lowering weight and increasing plasma triglyceride (TG) levels and hepatic fat compared with insulin glargine (GL) in patients with type 1 diabetes, the attenuated peripheral effects of basal insulin peglispro (BIL) may include increased free fatty acid flux to the liver, causing increased very-low-density lipoprotein (VLDL)-TG secretion and lipid oxidation, and decreased TG adipose tissue deposition. METHODS: In this open-label, randomized, 2-period crossover study, 14 patients with type 1 diabetes received once-daily, individualized, stable BIL or GL doses for 3 weeks. Palmitate flux was assessed using [9,10-3 H]palmitate infusion. VLDL-TG secretion, clearance and oxidation rate were assessed using primed-constant infusion of ex vivo labelled [1-14 C]VLDL-TG, while VLDL-TG storage rate was assessed using [9,10-3 H]VLDL-TG bolus injection. RESULTS: The VLDL-TG concentration and secretion rate, and palmitate flux were statistically significantly higher during BIL than during GL treatment (58%, 51% and 35%, respectively). The ratios of least squares (LS) geometric means for VLDL-TG clearance and oxidation were 0.92 (95% confidence interval [CI] 0.72, 1.17) and 1.31 (95% CI 0.91, 1.90), respectively. The difference in LS means for VLDL-TG storage rate was -0.36 (95% CI -0.83, 0.12). CONCLUSIONS: BIL-treated patients had higher effective lipolysis, VLDL-TG secretion and VLDL-TG concentration compared with GL-treated patients, explaining the increased plasma TG concentrations reported previously. Data support attenuated effects of BIL on lipolysis, in addition to the recently described hepato-preferential glucodynamic effects.