Serum Nitrosative Stress Levels Are Increased in Alzheimer Disease but Not in Vascular Dementia

The aim of this study was to investigate whether there is a difference between Alzheimer disease (AD) dementia and pure vascular dementia (VaD) in relation to nitrosative stress levels. We determined serum nitric oxide (NO), oxidized low-density lipoproteins (ox-LDL), and 3-nitrotyrosine levels (3-NT) in healthy elderly individuals (controls, n = 15, mean age = 73.4 +/- 7.9 y), AD patients (n = 30; mean age = 71.2 +/- 12.7 y) and VaD patients (n = 20; mean age = 75.2 +/- 7.5 y). Patients were under anticholinesterase drug therapy. Our results showed that serum NO and ox-LDL levels in AD patients group were significantly higher than in both controls (P < 0.001 and P < 0.001) and VaD patients (P < 0.01 and P < 0.001). However, no significant differences in plasma NO and ox-LDL levels were found between VaD and controls. Our study did not reveal significant differences in plasma 3-NT values of dementia patients when compared with controls. There was a significant negative correlation between Mini-Mental State Examination score and serum NO levels in dementia patients (r = -0.349, P < 0.01). Serum NO levels were also positively correlated with serum ox-LDL levels (r = 0.358, P < 0.01). In conclusion, elevation in serum levels of NO was present in probable AD patients but not in VaD patients, and this seems to be related to both ox-LDL levels and cognitive status.