Apoptosis (programmed cell death) is a chain of complex biochemical processes that regulate the cellular mechanisms. The study of apoptosis is a rapidly developing field, but its role is still not precise and controversial. This review discusses issues of apoptosis in the context of normal aging T-cells, cardiac myocytes, and cells of neural tissue. A special attention is given to caspases, death receptors, mitochondria, Bcl-2, Bcl-x and tumor suppressor genes, since they are considered to be the most important mediators of the programmed cell death. This review presents data of modern literature on the mechanisms of apoptosis, its difference from necrosis, the molecular and genetic bases of its activation. Apoptosis is regulated by proteolytic enzymes called caspases, which activate cell death process by cleaving specific proteins. The activation is initiated either by extracellular or intracellular death signals, which is why there are two pathaways of initiation: an extrinsic and an intrinsic one. An article focuses on the essential role of apoptosis in morphogenesis, embryogenesis and tissue growth, its importance in biology and medicine, and in the maintenance of homeostasis. Apoptosis is overviewed at the molecular and cellular levels, special attention is paid to the proteins and inhibitors of this process, as well as to its biomarkers. Apoptosis involves a cascade of complicated processes that include the delivery of signals through the receptor complexes, an execution of programmed cell death by proteases and endonucleases and the well-regulated expression of a number of genes. The latest studies are aimed at the connection of apoptosis and various pathological conditions. More frequently diseases are caused either by extensive, or by insufficient apoptosis. But the pathologies may also occur due to defects or abnormalities of the process itself. The attention is also given to the role of apoptosis in the theory of schizophrenia and the theory of aging. It was proved, that anomalies in the regulation of the apoptosis are crucial to the development of diseases such as cancer, AIDS, myocardial infarction and stroke, ischemia and neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, Huntington's disease and amyotrophic lateral sclerosis. With a better understanding of the molecular mechanisms, that regulate the death pathaway and further investigation in problems of the programmed cell death, it is clear, that an enormous amount of opportunities will become opened. The scientists will be able to devise targeted therapies and new treatment strategies. However, before the use of new ways of treatment and drugs, before they can be used safely on humans, a multiple amount of critical tests must be passed. But surely apoptosis will be further studied and can become a key to not only understanding the worst diseases, but also to their treatment.
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