Differential chromosome sensitivity to 5-azacytidine in Alzheimer's disease.

Background: The methylation process in the DNA has been considered a control mechanism of gene activity, connected with genetic imprinting. 5-Azacytidine (5-AZC) is known to be a demethylation agent.
Objective: We studied the cytogenetic effect of 5-AZC in Alzheimer's disease patients and in two control groups.
Methods: Peripheral lymphocyte cultures derived from 8 patients with Alzheimer's disease and 8 elderly and 8 healthy young individuals, all female, were studied. The parameters investigated were: the undercondensation of constitutive heterochromatin of chromosomes 1, 9, and 16: the number of lesions in fragile sites 1q42 and 19q13; heterochromatin association, and the total number of induced lesions.
Results: Our results showed a significantly increased frequency of undercondensation of chromosomes 1, 9, and 16 in Alzheimer's disease patients when compared with elderly and young healthy groups.
Conclusion: These results suggest that the demethylating action of 5-AZC could reveal differential gene activity in the Alzheimer group at the level of cellular division.