Cytokines and Aging

Abstract

Cytokines are secretory or membrane-bound protein families produced mainly by cells of the vertebrate immune system for immunity of the organisms against external challenges such as bacterial, viral and other pathogen infections. However, other cell types also secrete cytokines for many physiological functions. Cytokines are involved in cell proliferation, cell differentiation, cell death, immune function and many other physiologically important cellular responses. Generally, cytokines are produced in small quantities by cells in close proximity of the target cells and their actions on cells lead to cascades of cellular signal transduction pathways leading to physiological responses needed for cell survival. Under certain abnormal conditions, excessive or aberrant production and action of cytokines can lead to various pathological conditions in cells and tissues as well as diseases in mammals. It is now increasingly realized that during aging of mammalian cells and tissues, functions of many cytokines become abnormal and this leads to low-grade chronic inflammation causing various age-related pathogenesis and diseases. It is, therefore, important to understand first how cytokine-mediated functions become abnormal during aging and second which of these aspects may serve as control points to slow-down or block such abnormalities. Such topics are important for understanding biology of aging at cellular and organism levels as well as designing possible therapeutic strategies for age-related diseases. Here, we describe the relationship of cytokines and aging in mammals with reference to certain major tissues and organs as well as age-related diseases such as brain and neurodegenerative diseases; bone and osteoarthritis; kidney and chronic kidney disease; pancreas, adipose tissue and diabetes, obesity; eye and retinal degeneration; muscle and sarcopenia, liver and liver disease. Thus "cytokines and aging" is an important dimension of biogerontology and geriatrics.