INTRAPERITONEAL INSULIN DELIVERY DECREASES THE LEVELS OF CHYLOMICRON REMNANTS IN PATIENTS WITH IDDM

OBJECTIVE - To investigate whether intraperitoneal insulin infusion (I PII) decreases the levels of circulating chylomicron remnants in patie nts with insulin-dependent diabetes mellitus (IDDM). RESEARCH DESIGN A ND METHODS - Eight nonobese, normolipidemic IDDM patients were studied twice: before (while on subcutaneous insulin) and 6 months after init iation of IPII by a programmable implanted medication system. Fasting and mean blood glucose, HbA(1), and lipid values were determined. Bloo d samples were also drawn before and every 2 h for 10 h after ingestio n of a fat meal (corn oil + Vitamin A). Triglycerides (TGs), apolipopr otein B (apoB), and retinyl esters were determined over time in two TG -rich lipoprotein subfractions (S-f > 100 and S-f 20-100) isolated fro m plasma by density-gradient ultracentrifugation. RESULTS - IPII sligh tly decreased the mean blood glucose from 7.8 +/- 1.1 to 7.4 +/- 1.1 m mol/l (mean +/- SD, P = 0.027, paired Student's t test) and the HbA(1) from 9.4 +/- 1.5 to 8.7 +/- 1.2 (NS). TG and apoB levels in postprand ial S-f > 100 and S-f 20-100 were not changed by IPII. On IPII, howeve r, retinyl ester levels in S-f >100 decreased (P = 0.05, analysis of v ariance [ANOVA]) and tended to be lower in S-f 20-100 (P = 0.075). In addition, following IPII, the retinyl ester:apoB ratio was lower in S- f >100 (P = 0.0002) and marginally lower (P = 0.06) in S-f 20-100. CON CLUSIONS - IPII decreased chylomicron remnant levels, which might decr ease the atherosclerotic risk in IDDM. Since glycemic control was only slightly improved, the effect was most likely due to the intraperiton eal route of delivery.