Treatment With Artificial β-Cell Decreases Very-Low-Density Lipoprotein Triglyceride Synthesis in Type I Diabetes

The effect of restoration of euglycemia with the artificial β-cell (Biostator GCIIS) on triglyceride metabolism was studied in seven normolipidemic patients with type I diabetes mellitus. Very-low-density lipoprotein triglyceride (VLDL-TG) transport was determined with [³H]glycerol as an endogenous precursor of VLDL-TG; the resultant kinetic data were evaluated by multicompartmental analysis. Studies of triglyceride metabolism were performed in diabetic patients taking their usual dose of subcutaneous insulin (control study) and after 72 h of euglycemia with the artificial β-cell (Biostator study). Treatment with the artificial β-cell resulted in a decrease in mean (±SE) 24-h plasma glucose levels from 199 ± 9 to 123 ± 7 mg/dl and an increase in mean plasma freeinsulin levels from 12.3 ± 1.9 to 27.6 ± 4.2 μU/ml (P < .05). These changes were accompanied by a decrease in mean plasma TG levels from 134 ± 29 to 88 ± 15 mg/dl (P < .05). Kinetic studies demonstrated that the change in plasma triglyceride levels was primarily due to a decrease in VLOL-TG transport (i.e., synthesis), which fell from 11.7 ± 2.5 mg · h⁻¹ · kg⁻¹ ideal wt during the control study to 7.5 ± 2.0 mg · h⁻¹ · kg⁻¹ ideal wt during the Biostator study (P < .05). There was no significant change in fractional catabolic rates of VLDL-TG between the two studies (0.35 ± .05 vs. 0.38 ± .07 h⁻¹). Thus, our data suggest that the decrease in plasma TG levels after short-term restoration of euglycemia with the artificial β-cell is due to a decrease in VLDL-TG synthesis.