Serum 8-hydroxy-guanine levels are increased in diabetic patients.
OBJECTIVE
The production of reactive oxygen species is increased in diabetic patients, especially in those will poor glycemic control. We have investigated oxidative damage in type 2 diabetic patients using serum 8-hydroxyguanine (8-OHG) as a biomarker.


METHODS
We studied 41 type 2 diabetic patients and compared them with 3 nondiabetic control subjects. Serum 8-OHG concentration was assayed using high-pressure liquid chromatography.


RESULTS
The type 2 diabetic patients had significantly higher concentrations of 8-OHG in their serum than the control subjects (5.03 +/- 0.69 vs. 0.96 +/- 0.15 pmol/ml P < 0.01). There was no association between the levels of 8-OHG and HbA1c. We also could not and any correlation between serum 8-OHG levels and age, duration of diabetes, serum lipids, or creatinine or albumin exeretion rate. Creatinine clearance showed marginal correlation with serum 8-OHG levels (P = 0.06). Among the diabetic patients, those with proliferative retinopathy had significantly higher 8-OHG levels than those with nonproliferative retinopathy or without retinopathy. Likewise, the serum 8-OHG levels in patients who had advanced nephropathy (azotemia) were higher than in patients with normoalbuminuria, microalbuminuria, or overt proteinuria.


CONCLUSIONS
Our findings show that measuring serum 8-OHG is a novel convenient method for evaluating oxidative DNA damage. Diabetic patients, especially those with advanced microvascular complications, had significantly higher serum 8-OHG levels; this suggests that such changes may contribute to the development of microvascular complications of diabetes.
Shin
C S
CS
Department of Internal Medicine, the Institute of Endocrinology, Nutrition and Metabolism Research, Seoul National University College of Medicine, Korea.
Moon
B S
BS
Park
K S
KS
Kim
S Y
SY
Park
S J
SJ
Chung
M H
MH
Lee
H K
HK
D000419:Albuminuria; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D003404:Creatinine / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000652:urine; D003930:Diabetic Retinopathy / Q000097:blood; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006147:Guanine / Q000031:analogs & derivatives* / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017382:Reactive Oxygen Species; D012016:Reference Values; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
D015415:Biomarkers; D001786:Blood Glucose; D002784:Cholesterol; D008076:Cholesterol, HDL; D003404:Creatinine; D006442:Glycated Hemoglobin; D006147:Guanine; D017382:Reactive Oxygen Species; D014280:Triglycerides; C024829:8-hydroxyguanine