Associations of LDL size with in vitro oxidizability and plasma levels of in vivo oxidized LDL in Type 2 diabetic patients.
OBJECTIVE
Oxidative modification of low-density lipoprotein (LDL) is believed to be a key step in the genesis of atherosclerotic lesions. The presence of small, dense LDL is associated with accelerated atherosclerosis and is common in diabetic patients. The aim of this study was to investigate the relationship of in vitro LDL oxidizability and circulating in vivo oxidized LDL with LDL particle size in Type 2 diabetic patients and healthy control subjects.


METHODS
The study group consisted of 58 elderly well controlled Type 2 diabetic patients and 58 control subjects with normal glucose metabolism. LDL particle size was measured by high-performance gel-filtration chromatography. In vitro oxidizability of LDL was measured by monitoring conjugated diene formation and plasma levels of circulating oxidized LDL were determined by ELISA.


RESULTS
In vitro susceptibility of LDL to oxidation was not related to plasma levels of in vivo oxidized LDL, nor to LDL particle size. In the diabetic patients, but not in the control group, an inverse relation between LDL size and in vivo oxidized LDL was observed (r=-0.35, P=0.007). This relation was strengthened after controlling for LDL-cholesterol concentration (r=-0.52, P<0.001).


CONCLUSIONS
In agreement with the view that small, dense LDL accelerates atherosclerosis, an inverse relationship was observed between LDL size and circulating in vivo oxidized LDL in Type 2 diabetic patients. Our results also suggest that in vitro susceptibility to oxidation is not a suitable surrogate measure for in vivo LDL oxidation.
Scheffer
P G
PG
Metabolic Laboratory, Department of Clinical Chemistry, VU University Medical Centre, Amsterdam, The Netherlands. p.scheffer@vumc.nl
Bos
G
G
Volwater
H G F M
HG
Dekker
J M
JM
Heine
R J
RJ
Teerlink
T
T
D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D010084:Oxidation-Reduction; D010316:Particle Size
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D008077:Lipoproteins, LDL