Blood Markers of Oxidative Stress in Dementia

ABSTRACT

OBJECTIVES: To identify changes in blood markers of oxidative stress among dementic and healthy aged persons, and to compare levels of peripheral markers of oxidative stress between dementia of the Alzheimer's type (DAT) and vascular dementia (VD), and finally to analyze factors affecting those. DESIGN: Some antioxidants had been known to reduce the risk of dementia, while increase of 4-hydroxy-nonenal and decrease of heme oxygenase in DAT had been reported. Recently increased free radical activities were also found in VD. Therefore, this study was tried to search for a blood markers to discriminate DAT and VD. MATERIALS AND METHOD: The blood levels of total antioxidant capacity (TAC) and catalase activity of 50 patients with DAT and 50 patients with VD were compared with those of 56 healthy aged controls. In addition, variables including risk factors of dementia, degree of dementia measured by MMSE, Hasegawa Dementia Scale, GDS and CDR, and activities of daily living were also assessed. RESULTS: 1) The levels of TAC were significantly (p<0.01) lower in dementia than normal aged controls (1.47+/-0.08 mmol/L), while the catalase activities were significantly (p<0.01) higher in dementia than normal aged controls (45.61+/-11.67 kU/L). 2) The TAC levels were significantly (p<0.01) lower while the catalase significantly (p<0.01) higher in DAT (1.24+/-0.09 mmol/L, 133.42+/-58.45 kU/L respectively) than VD (1.31+/-0.08 mmol/L, 81.33+/-24.65 kU/L respectively). 3) The TAC and catalase activities were significantly (p<0.01) correlated with duration of dementia, behavior symptoms, activities of daily living, and the severity of dementia. CONCLUSIONS: Peripheral blood markers of oxidative stress were significantly different in dementia from normal aged controls. Furthermore, the difference was more severe in DAT than VD, which means the effect of oxidative stress is more in DAT than in VD. Therefore, they might be clinically useful to assess and discriminate dementia.