Journal of cellular biochemistry
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p21 (CDKN1A, Cip1, Waf1) is a cyclin-dependent kinase inhibitor capable of causing cell cycle arrest or promoting cell cycle transit as well as acting as a regulator of apoptosis. In this study, we analyzed the effects of various antemortem conditions on p21 protein level and expression profiles of known p21 transcript variants in human heart tissue. The selected death cause groups were: non-cardiac, hypothermia, acute ischemia, and chronic hypoxia. ⋯ In acute ischemia deaths increased expression of variant p21B, suggested to be proapoptotic in several cell lines, was observed. Our results suggest a role for variant p21 alt-a in hypoxia and for variant p21B in acute myocardial ischemia. The known cardioprotective aspect of hypothermia might come from an increased p21 protein level.