Erytrocyte membrane anionic charge in type 2 diabetic patients with retinopathy.
BACKGROUND
The Steno hypothesis states that changes in basement membrane anionic charge leads to diabetic microvascular complications. In diabetic nephropathy, loss of basement membrane glycosaminoglycans and the association between glomerular basement membrane heparan sulphate and proteinuria has been documented. A correlation between erythrocyte surface and the glomerular capillary wall charges has also been observed. The aim of this study is to evaluate the relationship between retinopathy and erythrocyte anionic charge and urinary glycosaminoglycan excretion in type 2 diabetic patients.


METHODS
49 subjects (58 +/- 7 yrs, M/F 27/22) with type 2 diabetes with proliferative retinopathy (n = 13), nonproliferative retinopathy (n = 13) and without retinopathy (n = 23) were included in the study. 38 healthy subjects were selected as control group (57 +/- 5 yrs, M/F 19/19). Erythrocyte anionic charge (EAC) was determined by the binding of the cationic dye, alcian blue. Urinary glycosaminoglycan and microalbumin excretion were measured.


RESULTS
EAC was significantly decreased in diabetic patients with retinopathy (255 +/- 30 ng alcian blue/10(6) RBC, 312 +/- 30 ng alcian blue/10(6) RBC for diabetic and control groups respectively, p < 0.001). We did not observe an association between urinary GAG and microalbumin excretion and diabetic retinopathy. EAC is found to be negatively correlated with microalbuminuria in all groups.


CONCLUSIONS
We conclude that type 2 diabetic patients with low erythrocyte anionic charge are associated with diabetic retinopathy. Reduction of negative charge of basement membranes may indicate general changes in microvasculature rather than retinopathy. More prospective and large studies needs to clarify the role of glycosaminoglycans on progression of retinopathy in type 2 diabetic patients.
SSK Sevket Yilmaz Hospital, Section of Clinical Chemistry, Turkey. yaseminbudak2000@yahoo.com
Yasemin
Y
Budak
Hakan
H
Demirci
Muberra
M
Akdogan
Dilek
D
Yavuz
D000419:Albuminuria / Q000652:urine; D000423:Alcian Blue / Q000378:metabolism; D000838:Anions / Q000378:metabolism; D001786:Blood Glucose / Q000032:analysis; D004396:Coloring Agents / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000652:urine; D003930:Diabetic Retinopathy / Q000097:blood* / Q000652:urine; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005260:Female; D006025:Glycosaminoglycans / Q000652:urine; D006801:Humans; D008297:Male; D008875:Middle Aged; D019158:N-Acetylneuraminic Acid / Q000097:blood
D000838:Anions; D001786:Blood Glucose; D004396:Coloring Agents; D006025:Glycosaminoglycans; D019158:N-Acetylneuraminic Acid; D000423:Alcian Blue