Circadian change of serum concentration of small dense LDL-cholesterol in type 2 diabetic patients.
BACKGROUND
Type 2 diabetic patients have a higher risk of atherosclerosis than non-diabetic subjects. This difference may be attributable to increased levels of small dense low-density lipoprotein-cholesterol (sLDL-C) in diabetic patients. As the sLDL-C concentration is elevated in hypertriglyceridemia, which is exaggerated postprandially, we examined whether the sLDL-C level increases postprandially in type 2 diabetes.


METHODS
We obtained 7 blood samples (30min before and 2h after each meal, and at midnight) from 15 patients with diabetes and ten normal controls. Following the precipitation of very low-density lipoprotein and large buoyant LDL (bLDL) with heparin-Mg(2+), the sLDL-C concentration was determined as the cholesterol concentration by a homogeneous assay.


RESULTS
The fasting sLDL-C concentration was 60.3% higher in the diabetic patients than in the controls (1.01+/-0.21 vs. 0.63+/-0.21mmol/l, p<0.001). The sLDL-C concentrations in both groups were highest in the fasting state, decreased after breakfast, and remained low until midnight. The maximal reduction in the absolute sLDL-C concentration was 56.5% greater in the diabetic patients than in the controls (0.36+/-0.13 vs. 0.23+/-0.16mmol/l, p<0.05). Thus, the sLDL-C/bLDL-cholesterol (bLDL-C) ratio was reduced with increases in bLDL-C.


CONCLUSIONS
The sLDL-C concentration decreases postprandially in diabetes. This absolute reduction in sLDL-C may contribute to an acceleration of atherosclerosis in diabetic patients.
Hirayama
Satoshi
S
Department of Clinical Laboratory Medicine, Juntendo University School of Medicine, Tokyo, Japan. sthiraya@juntendo.ac.jp
Soda
Satoshi
S
Ito
Yasuki
Y
Matsui
Hiroshi
H
Ueno
Tsuyoshi
T
Fukushima
Yoshifumi
Y
Ohmura
Hirotoshi
H
Hanyu
Osamu
O
Aizawa
Yoshifusa
Y
Miida
Takashi
T
D000328:Adult; D016022:Case-Control Studies; D053480:Cholesterol Ester Transfer Proteins / Q000378:metabolism; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood*; D002940:Circadian Rhythm; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000378:metabolism / Q000503:physiopathology*; D005215:Fasting; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D014280:Triglycerides / Q000097:blood
C506642:CETP protein, human; D053480:Cholesterol Ester Transfer Proteins; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D014280:Triglycerides