Monocytes in Aging and Exercise

AgingThe percentage of Americans over the age of 65 is expected to increase to nearly 20% by 2030 [1].This change will have significant effects on the economy, healthcare, and society in general.Aging is the highest risk factor for the majority of chronic diseases -including cardiovascular disease, diabetes, arthritis, and cancer [2].While lifespan continues to rise, healthspan(definition) (the length of time someone is healthy) has increased more slowly and Americans are living longer with impaired health and disabilities [3].Interventions are needed to improve the health and quality of life of the aging population, and studies show that the compression of morbidity is possible with lifestyle changes, pharmaceuticals, and continuous medical advances [2]. InflammagingAging is associated with chronic, low-level, systemic inflammation (termed inflammaging(definition)) that contributes to most, if not all, age-related diseases [4].Older adults have higher serum levels of several pro-inflammatory cytokines/proteins such as IL-6, IL-1ß, CRP, and TNF-α.Elevated levels of these molecules in circulation, most notably IL-6, are correlated with an increased risk of morbidity and mortality in elderly populations [5].Furthermore, they are associated with sarcopenia, malnutrition, reduced bone density, diabetes, arthritis, atherosclerosis, cognitive decline, and other diseases of aging [6].There is no consensus on the causes of inflammaging, though it's likely due to a host of factors that become dysregulated with age.These "telomere(definition) attrition, cellular senescence(definition))." style="text-decoration:underline dotted; text-underline-offset:2px; cursor:help;">hallmarks of aging(definition)" include reduced autophagy(definition) and mitophagy, accumulation of DNA and mtDNA damage leading to genomic instability, epigenetic changes, telomere shortening, cellular and immune senescence, dysbiosis, chronic antigenic stress, diminished proteostasis(definition), altered metabolic signaling, stem cell exhaustion, increased cellular garbage, and mitochondrial dysfunction(definition) [7].Specific details of the aging process and inflammaging are beyond the scope of this article and we recommend a comprehensive review article for more information [7].In this review article we focus on monocytes and their roles in diseases, aging, and exercise. Monocytes Monocytes are circulating mononuclear phagocytes of the ReviewExercise Medicine