Apoptosis: Molecular mechanisms, regulation and role in pathogenesis.

OBJECTIVE: To review the current state of knowledge of apoptosis, with an emphasis on identifying potential and established roles for apoptosis in the pathogenesis of infectious diseases. DATA SOURCES: MEDLINE and the University of British Columbia library system were searched using the search subject, "apoptosis", for the years 1992 to 1996. Further search terms (eg, "pathogenesis") were used to narrow the results. These review articles and reference books were used as the basis for locating original articles on particular studies. DATA SELECTION: Approximately 40 studies were reviewed, with the criterion for selection being the relevance to either the molecular mechanisms behind apoptosis or roles for apoptosis in the pathogenesis of infectious diseases. DATA EXTRACTION: Relevant information from each study was collated into categories specific to morphological and biochemical characterization, and the regulation and molecular mechanisms of apoptosis and its role in the pathogenesis of infectious diseases. DATA SYNTHESIS AND
CONCLUSIONS: Apoptosis is characterized by distinct morphological and biochemical changes that distinguish it from cell necrosis. Different signal transduction events and transcription factors can promote or inhibit apoptosis, although where and how these tie into the cell death pathway is still poorly understood. Apoptosis has been implicated in the pathogenesis of infectious diseases in two distinct ways: first, multicellular organisms use apoptosis to combat viral infections; and second, pathogens can alter the normal process of apoptosis in host cells by abnormal upregulation or downregulation. Many diseases have been shown to implicate apoptosis in their pathogenesis, raising the possibility of novel treatments for some disorders by therapeutically altering the occurrence and course of apoptosis. Therefore, further study of apoptosis in both health and disease needs to be rigorously pursued.