The Aging as a Consequence of Diverse Biological Processes
There are many theories that have proposed in order to understand the aging process, and the interpretation of these theories does not reflect an unified concept. With aging, the loss of functional and developmental capacity is evidenced, this reflecting a loss of operational ability of different cells, which are unavailable to function under the gene and environment pressure. Among the mechanisms of homeodynamics, the repair and synthesis of DNA, the capacity to detect and depure proteins, lipids, organelles and defective cells, amongst others, are all well described. The process of homeodynamics also works to maintain proper immune function that is capable of defending against pathogens and recognizing self-antigens in order to prevent the development of autoimmunity and to maintain a controlled inflammatory response. Based on this fundamental concept of homeodynamics, it has been possible to explain the mechanisms that contribute to the process of aging, in contrast to the physiological maintenance of the different pathways (e.g., DNA damage, DNA errors, free radicals, mitochondrial damage, injury/cell insult and theories of immunosenescence) and how these same maintenance pathways cause cells to respond to different stressors with apoptosis, senescence and repair. In this article, we review the theories of apoptosis, senescence and cell repair within the context of their role in the normal aging process.