Normalization of composition of triglyceride-rich lipoprotein subfractions in diabetic subjects during insulin infusion with programmable implantable medication system.

OBJECTIVE: To investigate whether long-term improved glycemic control by intraperitoneal insulin infusion normalizes the compositional abnormalities of triglyceride (TG)-rich lipoproteins in insulin-dependent diabetes mellitus (IDDM). RESEARCH DESIGN AND METHODS: Seven subjects were studied before and 12-14 mo after initiation of treatment with the programmable implantable medication system (PIMS). Plasma TG levels were measured, and the composition of three TG-rich lipoprotein subfractions (Svedberg flotation [Sf] greater than 400, 100-400, and 20-100) were analyzed before and every 1.5 for 7.5 h after ingestion of corn oil.
RESULTS: PIMS significantly improved glycemic control, as measured by mean blood glucose (P less than 0.02), and HbA1 (P less than 0.001, paired t test) levels. Weight loss was also observed during PIMS treatment. Significant changes occurred in the composition of TG-rich lipoprotein subfractions during PIMS treatment in both the fasting (P less than 0.002) and the postprandial (P less than 0.0001) state. Most changes were in the direction of nondiabetic values. PIMS treatment reduced the total cholesterol enrichment in IDDM subjects in all three subfractions in the postprandial state and the very-low-density lipoprotein subfractions (Sf 100-400 and 20-100) in the fasting state. Multivariate analysis showed that the compositional changes were affected by improved glycemic control, as assessed by both mean blood glucose and HbA1, whereas the very-low-density lipoprotein compositional changes were by both the improved glycemic control and body weight.
CONCLUSIONS: In IDDM subjects during PIMS treatment, there was normalization of most abnormalities in the composition of fasting and postprandial TG-rich lipoproteins, including enrichment in total cholesterol, which is considered atherogenic.