Abstract
To elucidate the initial compositional changes in cell lipids and the progress of atherosclerosis in diabetics, we analyzed lipid fractions in intimamedia tissues separated from the arch, renal and abdominal portions of aorta from 8 non-diabetic and 4 type-2 diabetic autopsy cases. Intima-media was homogenized in 0.13M Tris-HCl buffer and centrifuged. Total lipids (sulfo-phospho-vanillin method), lipid fraction (TLC), phospholipid fraction (TLC) and protein (Lowry's method) in the supernatant were measured.
Total lipid content was 7.8±1.1mg/g wet weight (M±SE) in non-diabetics and it raised significantly (p<0.02) to 15.0±3.3mg/g wet weight in diabetics. Cholesteryl ester was dominant and triglyceride raised most remarkably to 1.9±0.6mg/g wet weight in diabetics (non-diabetics: 0.5±0.1mg/g wet weight). Phospholipids reduced significantly (p<0.05) to 1.3±0.3mg/g wet weight in diabetics (non-diabetics: 2.2±0.2mg/g wet weight). In phospholipid subfraction, phosphatidylcholine reduced significantly (p<0.05) to 0.30±0.29mg/g wet weight (non-diabetics: 0.55±0.05mg/g wet weight) and sphingomyelin (p<0.005) to 0.96±0.25mg/g wet weight (non-diabetics: 1.57±0.19mg/g wet weight). But, there were no differences between diabetics (0.53±0.09) and non-diabetics (0.52±0.06) in phosphatidylcholine/sphingomyelin ratio.
We supposed the decrease of phospholipids might cause the disorder of permeability in the aortic cell membranes, resulting in the accumulation of the TG-rich lipoproteins that are known to increase in diabetics.
