INCREASED BLEED MERCURY LEVELS IN PATIENTS WITH ALZHEIMERS-DISEASE

Alzheimer's disease (AD) is a common neurodegenerative disorder that l eads to dementia and death. In addition to several genetic parameters, various environmental factors may influence the risk of getting AD. I n order to test whether blood levels of the heavy metal mercury are in creased in AD, we measured blood mercury concentrations in AD patients (n = 33), and compared them to age-matched control patients with majo r depression (MD) (n = 45), as well as to an additional control group of patients with various nonpsychiatric disorders (n = 65). Blood merc ury levels were more than two-fold higher in AD patients as compared t o both control groups (p = 0.0005, and p = 0.0000, respectively). In e arly onset AD patients (n = 13), blood mercury levels were almost thre e-fold higher as compared to controls (p = 0.0002, and p = 0.0000, res pectively). These increases were unrelated to the patients' dental sta tus. Linear regression analysis of blood mercury concentrations and CS F levels of amyloid beta-peptide (A beta) revealed a significant corre lation of these measures in AD patients (n = 15, r = 0.7440, p = 0.001 5, Pearson type of correlation). These results demonstrate elevated bl ood levels of mercury in AD, and they suggest that this increase of me rcury levels is associated with high CSF levels of AB, whereas tau lev els were unrelated. Possible explanations of increased blood mercury l evels in AD include yet unidentified environmental sources or release from brain tissue with the advance in neuronal death.