Alzheimer's disease fibroblasts have normal repair of N-methyl-N'-nitro-N-nitrosoguanidine-induced DNA damage determined by the alkaline elution technique

Cultured fibroblast strains from two normal persons and from two patients with the neurodegeneration of Alzheimer's disease were exposed to the alkylating chemical N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Immediately after exposure and also after a 24-h repair incubation period the single-strand breaks in the cells' DNA were quantified by the alkaline elution technique. In contrast to a report by others using alkaline elution, MNNG, and these same strains, we found no evidence of deficient repair of MNNG-induced DNA damage in the Alzheimer's disease cells. The putative DNA repair defect in Alzheimer's disease should be investigated by methods other than the alkaline elution technique which measures only a small fraction of the damage induced by an alkylating chemical such as MNNG.