l208S Am J C/in Nuir l992;55:l208S-14S. Printed in USA. © 1992 American Society for Clinical Nutrition Apoptosis-programmed cell death: a role in the aging process?13

ABSTRACT Cells continuously exposed to genotoxic agents, such as oxygen free radicals (OFRs), deeply involved in the aging process use a variety of cellular defense mechanisms. These defense mechanisms include DNA repair enzymes, an-tioxidants, poly(ADP-ribosyl)polymerase (pADPRP), and stress proteins and they constitute an integrated network. An age-re-lated failure of the efficiency of this network can affect cell pro-liferation and cell death, two phenomena tightly linked and reg-ulated. Recent data from our laboratory on the role of DNA damage and pADPRP activation and on the type of cell death induced by OFRs in human lymphocytes are reviewed. In vitro and in vivo data on possible strategies to reduce oxidative stress in lymphocytes from normal and Down syndrome subjects, by using natural compounds and trace elements, are presented. They indicate that nicotinamide and L-carnitine protect human cells from OFR-induced damage and suggest that they are possible candidates as antiaging substances. Am J C/in Nuir l992;55