Variation of plasma oxidative DNA damage marker 8-hydroxy-2'-deoxyguanosine in patients with Alzheimer's disease versus vascular dementia / 中华老年医学杂志

ABSTRACT

Objective To observe the variation of plasma 8-hydroxy-2'-deoxyguanosine (8-OHdG),a biomarker of oxidative DNA damage,in patients with Alzheimer's disease (AD) versus vascular dementia (VaD),and to investigate the important role and the difference of oxidative DNA damage in the initiation and development of AD and VaD.Methods 35 AD patients,28 VaD patients and 23 age and sex matched normal controls were enrolled in this study.Plasma 8-OHdG was measured by an enzyme-linked immunosorbent assay (ELISA) method.Cognition function in AD and VaD patients was measured by Mini-Mental State Examination (MMSE).Results There were significant differences in plasma 8-OHdG concentrations among AD,VaD and control groups [(601.8±266.0) ng/L,(1748.0±665.6)ng/L,(352.0±94.5)ng/L,respectively,P＜0.001].Plasma 8-OHdG was significantly higher in VaD group than in control group (P＜0.05).While,there was no significant difference in plasma 8OHdG concentration between AD group and control group (P＞0.05).Plasma 8-OHdG was significantly higher in VaD group than in AD group (P＜0.05).Plasma 8-OHdG levels were positively related with age in AD,VaD and control groups (r=0.661,0.702,0.719,respectively,all P％0.01).No correlations were found between plasma 8-OHdG concentration and education level among the three groups (all P＞0.05).AD and VaD patients were subgrouped according to the risk factors including gender,smoking,hypertension,diabetes,hyperlipidemia.There were no significant differences in plasma 8-OHdG level between the subgroups (all P＞ 0.05).After adjusting for sex,age,education level,smoking,hypertension,hyperlipidemia and diabetes,logistic regression analysis showed that the probability of high plasma 8-OHdG level was higher in VaD group than in AD and control groups.Plasma 8-OHdG level had a negative correlation with MMSE score in VaD group (r=-0.592,P＜0.01),while no correlation was found between plasma 8-OHdG level and MMSE score in AD group (r =-0.122,P＞ 0.05).Conclusions There is significant oxidative DNA damage in VaD patients.Plasma oxidative DNA damage is more serious in VaD patients than in AD patients and healthy people.Plasma 8-OHdG level,a oxidative DNA damage biomarker,has a significant correlation with the degree of cognition impairment in VaD patients.