ISOLATION, CHARACTERIZATION, AND METABOLISM OF THE GLYCATED AND NONGLYCATED SUBFRACTIONS OF LOW-DENSITY LIPOPROTEINS ISOLATED FROM TYPE-I DIABETIC-PATIENTS AND NONDIABETIC SUBJECTS
Rl. Klein et al., ISOLATION, CHARACTERIZATION, AND METABOLISM OF THE GLYCATED AND NONGLYCATED SUBFRACTIONS OF LOW-DENSITY LIPOPROTEINS ISOLATED FROM TYPE-I DIABETIC-PATIENTS AND NONDIABETIC SUBJECTS, Diabetes, 44(9), 1995, pp. 1093-1098
Citations number
43
Categorie Soggetti
Endocrynology & Metabolism","Medicine, General & Internal
The total low-density lipoprotein (LDL) fraction was isolated from 21
patients with type I diabetes and 7 nondiabetic normolipemic subjects.
The LDL was separated into two subfractions, one glycated (G-LDL) and
one nonglycated (N-LDL), using affinity chromatography. G-LDL compris
ed 21.1 +/- 3.6 and 5.2 +/- 0.6% of the total LDL in diabetic patients
and normal subjects, respectively. G-LDL isolated from both diabetic
patients and normal subjects was significantly more glycated than N-LD
L isolated from the same subject. G-LDL isolated from both diabetic pa
tients and normal subjects was enriched in triglycerides. The metaboli
sm of N-LDL and G-LDL was investigated in human fibroblasts, which exp
ress only the classical LDL receptor, and in human monocyte-derived ma
crophages, which also express a receptor for G-LDL. In fibroblasts, th
e rates of receptor-mediated accumulation of N-LDL isolated from norma
l subjects and diabetic patients were significantly greater (P < 0.01)
than those of G-LDL. In contrast, when the same LDL subfractions were
incubated with human monocyte-derived macrophages, the rates of recep
tor-mediated accumulation of G-LDL isolated from both groups were sign
ificantly greater (P < 0.01) than those of N-LDL. Rates of degradation
of G-LDL by human macrophages were not significantly different hom th
ose of N-LDL during short-term incubations but reached statistical sig
nificance (P < 0.05) when LDL subfractions were incubated with cells f
or 24 h. G-LDL stimulated cholesteryl ester synthesis rates in human m
acrophages significantly (P < 0.05) more than N-LDL from the same subj
ect and thus may contribute to the increased prevalence of atheroscler
osis in diabetic patients.