A synopsis on aging—Theories, mechanisms and future prospects

Abstract

Answering the question as to why we age is tantamount to answering the question of what is life itself. There are countless theories as to why and how we age, but, until recently, the very definition of aging – senescence – was still uncertain. Here, we summarize the main views of the different models of senescence, with a special emphasis on the biochemical processes that accompany aging. Though inherently complex, aging is characterized by numerous changes that take place at different levels of the biological hierarchy. We therefore explore some of the most relevant changes that take place during aging and, finally, we overview the current status of emergent aging therapies and what the future holds for this field of research. From this multi-dimensional approach, it becomes clear that an integrative approach that couples aging research with systems biology, capable of providing novel insights into how and why we age, is necessary.

Cognitive Aging in Dogs

“…Most recently, a unified theory of aging has been proposed that encompasses major theories of aging [7] . The free-radical theory of aging provides explanations for the aging phenomena, including the connections between the average life spans of mammals and their basal metabolic rates [8] , as well as between disease and aging [9] .…”

“…Various theories have been put forth regarding the biological mechanisms that lead to aging, including free-radical-induced damages, molecular cross-linking, telomere shortening, and the presence of senescence genes in the DNA [7] . Most recently, a unified theory of aging has been proposed that encompasses major theories of aging [7] .…”

The significance of mitochondrial DNA half-life to the lifespan of post-mitotic cells

“…The biological mechanisms that determine aging have been the subject of intense study for many decades, and remain unresolved, controversial, but well reviewed [13]. The proliferation of mtDNA del is one factor in the process of aging and the pathology of neurodegenerative disease [19,23,42], but it is amenable to simulation and theoretical investigation.…”

Deprescription in elderly: A spotlight on pharmacoeconomic aspect

“…Aging is a complex process that may be described as a progressive unfavorable loss of adaptation of an individual organism as time passes. Functionally, it is considered to be a state of failure of maintenance that makes older people more liable to multiple diseases which are collectively the biggest causes of morbidity and mortality making prescription of drugs in aged subjects difficult . Furthermore, multiple comorbidities usually require multiple therapies (polypharmacy) with possible drug adverse effects and interactions .…”

“…Functionally, it is considered to be a state of failure of maintenance that makes older people more liable to multiple diseases which are collectively the biggest causes of morbidity and mortality making prescription of drugs in aged subjects difficult. [1][2][3] Furthermore, multiple comorbidities usually require multiple therapies (polypharmacy) with possible drug adverse effects and interactions. 4 The most common problems related to drug prescription in the aging population have been summarized in Figure 1.…”