Late to the Party? Pyroptosis Becomes a New Mechanism of Cell Death for Adipocytes

For many years, medical practitioners have thought that cells die in one of only two ways: Either necrotic cells die violently when their outer membrane ruptures, or cells undergo programmed silent cell death through a mechanism called apoptosis. In 2001 Cookson and Brennan published an article in Trends in Microbiology describing a new means of cell death that occurs usually within the context of an infectious process called pyroptosis. This method of cell death exists in a continuum between the opposite processes of necrosis and apoptosis, and it exhibits characteristics of both. Pyroptosis is caspase mediated, but its initiator is caspase-1 instead of caspase-2, -8, -9, and -10, which initiate apoptosis. Because the full pyroptotic process takes time, the severe swelling that characterizes tissue response to necrosis is absent. Pyroptotic cell death is not totally silent, however—lysosomal exocytosis is also a marker; therefore varying degrees of inflammation can be seen with this mechanism.