Blood levels of iron, copper, zinc, nitric oxide, and APOE [epsilon]4 allele frequency in patients with Alzheimer's disease

ABSTRACT

Alzheimer's disease [AD] is the most common form of dementia, characterized by slow, progressive memory loss. As the disease progresses other symptoms such as visuospatial disorientation, language impairment, and executive dysfunction or frontal lobe signs develop. The current study was performed to investigate the role of iron, copper, zinc, nitric oxide [NO] in relation to ApoE epsilon 4 allele frequencies in patients with AD. This study was carried out on sixty elderly subjects aged >/= 60 years. The subjects were classified into two groups matched for age and gender Group I included 30 elderly patients [74.3 +/- 7.2 years] diagnosed as probable Alzheimer's disease according to the DSM-IV-TR and the NINCDS-ADRDA. Group II included 30 cognitively normal elderly subjects [71.7 +/- 3.6 years] with no evidence of any neurological or psychiatric diseases, or any medical illness that affects cognition. Laboratory investigations were done for patients. The following plasma parameters were measured iron, copper, zinc and nitric oxide together with ApoE genotyping by PCR - RFLP. The current study revealed that plasma copper, zinc and nitric oxide levels were higher in AD group than control group. But, no statistically significant difference could be found between the two groups in plasma iron level. The frequency of ApoE 4 allele was higher among AD patients than control subjects. In comparison between ApoE4 +ve and ApoE4 -ve patients, no statistical significant difference in the neuropsychological assessment and biochemical assays was observed. Plasma copper level had statistically significant negative correlation with constructional praxis, ward list recognition, recall of constructional praxis, and stage of AD. While, iron, zinc, and NO plasma levels were not significantly correlated with any of the tested neuropsychological tests. We have demonstrated that, NO level had the highest sensitivity and specificity for predicting AD, followed by copper level. It can be concluded that, the ApoE4 gene is a strong risk factor for the AD but it is neither necessary, nor enough for the disease occurrence. Trace metals and NO abnormalities would influence ApoE, leading to development AD. Also, Copper blood levels are related to the abnormal cognition in AD patients