Interleukin 6 in aging and age-related diseases

Abstract

Modern concepts about the importance of subclinical inflammation in various age-associated pathology are described in the review. The term “inflammaging” (inflammation due to aging) refers to the special role of inflammation in the aging processes. This type of inflammation is low-grade, controlled, asymptomatic, chronic and systemic. Inflammaging determines the rate of aging and life expectancy. The balance of pro-inflammatory and anti-inflammatory cytokines plays a significant role in aging processes. The increased levels of pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-α in the elderly are associated with different diseases, disability and mortality. Interleukin-6 is a multifunctional cytokine involved in the regulation of acute phase response and other immunological reactions, in the hematopoiesis and in chronic inflammation. This cytokine is important in the pathogenesis of chronic inflammation diseases, as well as different oncological disorders. Interleukin-6 is often called the “cytokine of gerontologists”, since it is one of the main signaling pathways associated with aging and age-related diseases. This cytokine also plays an important role in the pathogenesis of atherosclerosis, coronary artery disease, chronic heart failure and increases the risk of death from cardiovascular diseases and overall mortality. Interleukin-6 is a key proinflammatory cytokine responsible for the “metabolic inflammation”, obesity, insulin resistance and diabetes mellitus. This cytokine has a significant impact on the development of sarcopenia and frailty. The serum levels of interleukin-6 negatively correlate with muscle mass and skeletal muscle function in the elderly, so it is considered as a biomarker of sarcopenia and functional decline. Interleukin-6 may contribute to the development of osteoporosis by stimulating osteoclastogenesis and bone resorption. The modern data indicate the diverse effects of interleukin-6 and confirm the significant role of this cytokine in aging and in different age-associated pathology.