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The identification of biological markers of Alzheimer's disease (AD) can be extremely useful to improve diagnostic accuracy and/or to monitor the efficacy of putative therapies. In this regard, peripheral cells may be of great importance, because of their easy accessibility. After subjects were grouped according to diagnosis, the expression of conformationally mutant p53 in blood cells was compared by immunoprecipitation or by a cytofluorimetric assay. In total, 104 patients with AD, 92 age-matched controls, 15 patients with Parkinson's disease and 9 with other types of dementia were analyzed. Two independent methods to evaluate the differential expression of a conformational mutant p53 were developed. Mononuclear cells were analyzed by immunoprecipitation or by flow-cytometric analysis, following incubation with a conformation-specific p53 antibody, which discriminates unfolded p53 tertiary structure. Mononuclear cells from AD patients express a higher amount of mutant-like p53 compared to non-AD subjects, thus supporting the study of conformational mutant p53 as a new putative marker to discriminate AD from non-AD patients. We also observed a strong positive correlation between the expression of p53 and the age of patients. The expression of p53 was independent from the length of illness and from the Mini Mental State Examination value.Molecular Psychiatry (2008) 13, 641–647; doi:10.1038/sj.mp.4002060; published online 7 August 2007 [ABSTRACT FROM AUTHOR]

The identification of biological markers of AD can improve diagnostic accuracy and therapy follow-up as well as provide information on the pathogenesis of the disease. We recently found that fibroblasts derived from AD patients expressed an altered conformational status of p53 and were less sensitive to p53-dependent apoptosis compared to fibroblasts from non-AD subjects. When investigating the mechanism of such alteration, we found that the exposure to nanomolar concentrations of amyloid-β (Aβ) 1-40 peptide induced the expression of an unfolded p53 protein isoform in fibroblasts derived from non-AD subjects. These data suggest that the tertiary structure of p53 and the sensitivity to p53-dependent apoptosis is influenced by low concentrations of soluble Aβ. On this basis, we hypothesized that low amounts of soluble Aβ induce early pathological changes at cellular level that may precede the amyloidogenic cascade. One of these changes is the induction of a novel conformational state of p53. If low amounts of Aβ peptide, not resulting in cytotoxic effects, are responsible for p53 structure changes, it could be possible to consider the unfolded p53 both as an agent participating to the early pathogenesis and as a specific marker of the early stage of AD. [ABSTRACT FROM AUTHOR]

The identification of biological markers of Alzheimer’s disease (AD) can be extremely useful to improve diagnostic accuracy and/or to monitor the efficacy of putative therapies. In this regard, peripheral cells may be of great importance because of their easy accessibility. After subjects were grouped according to diagnosis, the expression of conformational mutant p53 in blood cells was compared by immunoprecipitation or by a cytofluorimetric assay. One hundred and four patients with AD, 92 age-matched controls, 15 patients with Parkinson’s disease, and 9 with other types of dementia were analyzed. Two independent methods to evaluate the differential expression of a conformational mutant p53 were developed. Mononuclear cells were analyzed by immunoprecipitation or by flow cytometric analysis, following incubation with a conformation-specific p53 antibody, which discriminates unfolded p53 tertiary structure. Mononuclear cells from AD patients express a statistically significantly higher amount of mutant-like p53 compared to mononuclear cells from non-AD subjects, thus supporting the study of conformational mutant p53 as a new putative marker to discriminate AD from non-AD patients. We also observed a strong positive correlation between the expression of p53 and the age of patients. The expression of mutant p53 did not correlate with the duration of illness and the Mini Mental State Examination scores. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]