Spontaneous and induced aneuploidy in peripheral blood lymphocytes of patients with Alzheimer's disease

This study was aimed at assessing whether peripheral blood lymphocytes of patients with Alzheimer's disease (AD) show significant levels of aneuploidy and high percentages of cytogenetic events in vitro, indicating a predisposition to aneuploidy spontaneously, or after chemical treatment in vitro. A group of affected individuals and a group of unaffected, age-, sex- and smoking-habit-matched controls were identified. Lymphocytes were cultured for analysis of the following cytogenetic parameters: premature centromere division (PCD), satellite associations of acrocentric chromosomes (SA) and micronuclei (MN). In a subset of subjects, the fluorescence in situ hybridization (FISH) technique was combined with the MN assay, by means of a pancentromeric DNA probe for the detection of the presence of centric material. To evaluate the sensitivity to aneuploidogenic agents, in vitro treatment of lymphocytes of affected individuals was performed by adding griseofulvin, a chemical whose supposed target is microtubule-associated protein(s). Both the spontaneous frequency of MN and the frequency of PCD was significantly higher in patient cells than in controls. Furthermore, after application of the FISH technique, we found that the majority of MN were composed of whole chromosomes (because of the phenomenon of chromosome loss). Metaphase analysis for the detection of associative events between satellite regions of acrocentric chromosomes showed no differences between the two groups under study. Analysis of sensitivity to the aneuploidogen griseofulvin showed that the patient group was characterized by lower levels of MN induction compared with controls. Our data confirm that peripheral blood lymphocytes of AD patients are prone to undergo aneuploidy spontaneously in vitro and support the hypothesis that microtubule impairment might be associated with the disease.