Flow cytometry of apoptotic cell death

The term apoptosis or programmed cell death defines a genetically encoded c ell death program, which is morphologically and biochemically distinct from necrosis or accidental cell death. The characteristic morphological signs of apoptosis (cellular shrinkage, membrane blebbing, nuclear condensation a nd fragmentation) are the final results of a complex biochemical cascade of events which is an integral part of physiological homeostasis. Techniques designed to identify, quantitate and characterize apoptosis are numerous, b ut flow cytometry (FCM) remains the methodology of choice to study the apop totic cascade in relation to cell type, trigger and time. This review outli nes the main stages of the apoptotic cascade together with current FCM meth ods. All FCM apoptosis assays described have a solid experimental basis and have been used successfully in basic research on molecular and biochemical mechanisms of apoptosis. In various clinical settings the ability to follo w the apoptotic process in patient samples may offer the rationale for opti mal treatment schedules. (C) 2000 Elsevier Science B.V. All rights reserved .