Lymphocytes as cell model to study apoptosis in Alzheimer's disease: vulnerability to programmed cell death appears to be altered.

Recent evidence indicates that programmed cell death (apoptosis) may contribute to neuronal death in Alzheimer's disease (AD). In situ data derived from post mortem brain tissue indicate that DNA fragmentation which represents an important and typical apoptotic feature is markedly increased in brain cells of AD patients compared to controls. Furthermore, in vitro studies demonstrate that the peptide beta-amyloid (A beta) and its fragments induce apoptosis in neuronal cell cultures. One possible mechanism initiating apoptosis could be free radical generation by the peptide leading to oxidative stress. In a wide range of cell types common morphological and molecular events occur during apoptosis and several genes appear to be involved. Particularly in lymphocytes, apoptosis plays an important physiological role. Our data demonstrate that similar oxidative stressors induce apoptosis in mature human lymphocytes as in neurons. In addition, first evidence indicates that susceptibility to apoptosis is altered in lymphocytes from AD patients compared to non-demented controls. Our preliminary findings suggest that changes of the individual sensitivity to undergo cellular apoptosis are already detectable in lymphocytes from AD patients, probably as a consequence of genetic as well as other risk factors. Therefore, this biochemical marker might have the potential for identifying individuals at risk of the diseases.