Diabetes Care, Vol 17, Issue 1 6-12, Copyright © 1994 by American Diabetes Association
Normalization of lipoprotein composition by intraperitoneal insulin in IDDM. Role of increased hepatic lipase activity
G Ruotolo, M Parlavecchia, MR Taskinen, G Galimberti, A Zoppo, NA Le, F Ragogna, P Micossi and G Pozza
Department of Medicine (Laboratory of Lipoprotein Metabolism and Atherosclerosis), Scientific Institute H San Raffaele, University of Milan, Italy.
OBJECTIVE--To characterize the effects of intraperitoneal insulin pump
therapy on lipoprotein composition and lipolytic enzyme activity in
patients with insulin-dependent diabetes mellitus (IDDM). RESEARCH DESIGN
AND METHODS--Ten IDDM patients were studied 3 times: when receiving
conventional subcutaneous insulin therapy and at 3 and 9 months from the
initiation of intraperitoneal insulin regimen. Ten nondiabetic subjects
matched for age, sex, and body weight were studied as controls. Levels of
cholesterol, triglycerides, apolipoprotein A-I (apoA-I) and B (apoB) were
measured in total plasma and lipoprotein fractions (very-low-density
lipoprotein [VLDL], intermediate-density lipoprotein [IDL], low-density
lipoprotein [LDL], and high-density lipoprotein [HDL]: HDL2 and HDL3).
Postheparin plasma lipoprotein lipase and hepatic lipase activities were
determined by an immunochemical method. RESULTS--IDDM patients showed
higher levels of HDL3 and lower levels of HDL2 particles during
intraperitoneal insulin therapy in comparison with subcutaneous insulin
therapy. Both cholesterol and apoA-I significantly increased in HDL3 and
decreased in HDL2 during intraperitoneal treatment. Plasma total
cholesterol significantly decreased in the diabetic patients at 3 months of
intraperitoneal insulin therapy compared with both subcutaneous insulin
regimen and control subjects. IDL triglyceride concentrations during
intraperitoneal treatment were significantly lower than those seen with
subcutaneous therapy. Furthermore, triglyceride:apoB ratio in VLDL and
cholesterol:apoB ratio in LDL significantly decreased in IDDM patients
treated by intraperitoneal insulin. A significant increase in the activity
of hepatic lipase with intraperitoneal insulin therapy by 9 months compared
with subcutaneous insulin therapy has been shown. CONCLUSIONS--The
increased activity of hepatic lipase after intraperitoneal insulin
administration in IDDM patients appears to be one of the main determinants
of lipoprotein changes observed, resulting in the normalization of
lipoprotein composition during this mode of therapy. The normal inverse
relationship between VLDL triglycerides and HDL cholesterol, which was not
present in IDDM patients with subcutaneous therapy, was restored with
intraperitoneal insulin regimen.