Immunochemical quantification of crossline as a fluorescent advanced glycation endproduct in erythrocyte membrane proteins from diabetic patients with or without retinopathy.
Crossline is a novel advanced glycation endproduct (AGE) which has both a crosslink and fluorescence similar to AGE-protein in vivo. To assess the association of AGEs to the development of diabetic retinopathy we developed a sensitive and specific enzyme-linked immunosorbent assay (ELISA) for crossline in blood samples and investigated the association of the development of retinopathy and erythrocyte membrane protein (EMP)-crossline concentrations in patients with Type 2 diabetes mellitus (Type 2 DM). Crossline formation in EMP exceeded that in haemoglobin and was detectable in normal EMP samples without pretreatment by this ELISA system. Mean (+/-SE) EMP crossline levels were elevated 1.6-fold in diabetic patients without retinopathy (7.6 +/- 0.5 pmol mg(-1), p < 0.005), 2.2-fold in diabetic patients with non-proliferative retinopathy (10.5 +/- 0.6 pmol mg(-1), p < 0.001) and 2.6-fold in diabetic patients with proliferative retinopathy (12.0 +/- 0.6 pmol mg(-1), p < 0.001) compared with healthy control subjects (4.7 +/- 0.5 pmol mg(-1)). Type 2 DM patients with retinopathy had significantly higher EMP-crossline levels than those without retinopathy (p < 0.005). Our data suggest that elevated EMP-crossline concentrations are associated with the presence of retinopathy in patients with Type 2 DM and EMP-crossline measured by our ELISA may provide a useful marker for assessing the role of glycation in the development of diabetic retinopathy.
Yamaguchi
M
M
The First Department of Internal Medicine, Kyoto Prefectural University of Medicine, Japan.
Nakamura
N
N
Nakano
K
K
Kitagawa
Y
Y
Shigeta
H
H
Hasegawa
G
G
Ienaga
K
K
Nakamura
K
K
Nakazawa
Y
Y
Fukui
I
I
Obayashi
H
H
Kondo
M
M
D000368:Aged; D001798:Blood Proteins / Q000032:analysis*; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D003930:Diabetic Retinopathy / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D004910:Erythrocyte Membrane / Q000737:chemistry*; D005260:Female; D017127:Glycation End Products, Advanced / Q000097:blood*; D006801:Humans; D015416:Maillard Reaction; D008297:Male; D008565:Membrane Proteins / Q000032:analysis*; D008875:Middle Aged
D001798:Blood Proteins; D017127:Glycation End Products, Advanced; D008565:Membrane Proteins