PARP1 and Alzheimer disease: e) On the other hand, the greater cell death in our 21-month 3xTg-AD compared with non-Tg neurons could result from over activation of PARP-1 by both reactive oxygen species and beta-amyloid, consuming even more NAD to promote AIF-mediated apoptotic neuronal death (Strosznajder et al., 2012).