The Need to Discriminate Between Apoptosis and Necrosis

Although Fig. 13.2 describes a hypothetical situation, there is ample experimental evidence to suggest that both apoptosis and necrosis occur in a wide variety of disease conditions. A prominent example of this is the condition of ischemia-reperfusion injury in cardiovascular disease. Prolonged regional myocardial ischemia without reperfusion causes myocyte cell death. However, reperfusion after even a brief period of ischemia can also lead to cellular death even though restoration of blood flow is necessary to salvage the myocardium. 

This condition is referred to as ischemia-reperfusion injury. Several studies in animal models of ischemia-reperfusion injury have shown that the principal cause of cellular death is necrosis (11-13). However, other smdies have shown that cellular death consisted of a necrotic core surrounded by a peri-necrotic area that displayed properties consistent with apoptosis (11,14-18). Therefore, it is likely that cellular death resulting from ischemia-reperfusion injury can consist of a mixture of apoptosis and necrosis, depending on the extent and duration of the ischemia prior to reperfusion. Other disease conditions where evidence demonstrating both apoptosis and necrosis occur includes diabetic cardiomyopathy, sepsis, stroke, and the neurodegenerative disorders Alzheimer s disease and Parkinson s disease. The development of a noninvasive imaging technique capable of measuring apoptosis and necrosis independently could provide valuable information on the balance between apoptosis and necrosis, and if there is a temporal shift in the balance of these mechanisms of cellular death, in a wide variety of pathological conditions. 

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