Abnormal distribution of VLDL subfractions in type 1 (insulin-dependent) diabetic patients: could plasma lipase activities play a role?
Very low density lipoproteins (VLDL) have an abnormal lipid composition in Type 1 (insulin-dependent) diabetic patients. Since VLDL represent a heterogeneous lipoprotein class, this might be due either to a shift in the distribution or to an abnormal composition of VLDL subclasses or both. In order to investigate these possibilities and to evaluate possible pathogenetic mechanisms, lipid composition (non-esterified and esterified cholesterol, triglycerides, phospholipids) of four VLDL subfractions of decreasing size (A: Svedberg flotation unit [Sf] > 400, B: Sf > 400, B: Sf 175-400, C: Sf 100-175, D: Sf 20-100), isolated by density gradient preparative ultracentrifugation, and plasma post-heparin lipolytic activity (lipoprotein lipase and hepatic lipase) were evaluated in 13 male normolipidaemic insulin-dependent diabetic patients in good glycaemic control (HbAlc 6.9 +/- 0.5%) (mean +/- SEM) and 9 male control subjects matched for age, body mass index and plasma lipid values. Compared to control subjects, diabetic patients showed a reduced total lipid concentration of VLDL of intermediate size (B and C) reaching statistical significance only for VLDL C (0.16 +/- 0.02 vs 0.24 +/- 0.03 mmol/l; p < 0.05). Expressing each VLDL subfraction as percent of the total VLDL lipid concentration, a significant decrease in particles of intermediate size (C) (20.5 +/- 1.6 vs 27.9 +/- 1.5%; p < 0.005) was present, which was compensated by an increase in the smallest ones (D) (50.5 +/- 2.7 vs 37.4 +/- 3.1%; p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Patti
L
L
Institute of Internal Medicine and Metabolic Diseases, Second Medical School, University Federico II, Naples, Italy.
Romano
G
G
Di Marino
L
L
Annuzzi
G
G
Mancini
M
M
Riccardi
G
G
Rivellese
A A
AA
D000328:Adult; D003124:Colorimetry; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy; D006801:Humans; D007328:Insulin / Q000097:blood / Q000627:therapeutic use; D008049:Lipase / Q000097:blood / Q000502:physiology*; D008079:Lipoproteins, VLDL / Q000032:analysis*; D008099:Liver / Q000201:enzymology; D008297:Male; D014461:Ultracentrifugation
D007328:Insulin; D008079:Lipoproteins, VLDL; D008049:Lipase