Triglyceride-rich lipoproteins from subjects with type 2 diabetes do not demonstrate increased binding to biglycan, a vascular proteoglycan.
Retention of atherogenic apolipoprotein (apo) B- and E- containing lipoproteins by their interaction with arterial wall proteoglycans is important in atherogenesis. Levels of triglyceride (TG)-rich lipoproteins, which contain both apo B and apo E, are increased in type 2 diabetes. Because increased retention of TG-rich lipoproteins in diabetes might explain, in part, the increased atherosclerosis in this disorder, TG-rich lipoproteins were isolated from fasting type 2 diabetic subjects and age-matched controls, and assessed for their ability to bind biglycan, a vascular smooth muscle cell-derived proteoglycan. The binding of TG-rich lipoproteins isolated from diabetic subjects to purified biglycan did not differ from lipoproteins isolated from control subjects. Moreover, contrary to previous reports, no difference in the apo E content of TG-rich lipoproteins was detected between the control and diabetic groups. Additionally, no difference in the binding affinity of TG-rich lipoproteins for the low-density lipoprotein receptor was observed between control and diabetic subjects. Thus, we were unable to confirm previous reports that TG-rich lipoproteins from subjects with diabetes are enriched in apo E compared with age-matched controls, consistent with the lack of difference in binding of these lipoproteins to either biglycan or the low-density lipoprotein receptor. Therefore, increased affinity of TG-rich lipoproteins for biglycan is unlikely to explain the increased atherosclerosis in type 2 diabetes.
Tannock
Lisa R
LR
Department of Medicine, University of Washington, Seattle, Washington 98195, USA.
Olin
Katherine L
KL
Barrett
P Hugh R
PH
Wight
Thomas N
TN
Chait
Alan
A
D000328:Adult; D000368:Aged; D001057:Apolipoproteins E / Q000378:metabolism; D001161:Arteriosclerosis / Q000209:etiology; D058578:Biglycan; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications / Q000378:metabolism*; D016326:Extracellular Matrix Proteins; D006801:Humans; D008074:Lipoproteins / Q000097:blood*; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000378:metabolism; D011485:Protein Binding; D011509:Proteoglycans / Q000378:metabolism*; D011973:Receptors, LDL / Q000378:metabolism; D014280:Triglycerides / Q000032:analysis*
D001057:Apolipoproteins E; C546884:BGN protein, human; D058578:Biglycan; D016326:Extracellular Matrix Proteins; D008074:Lipoproteins; D011509:Proteoglycans; D011973:Receptors, LDL; D014280:Triglycerides