Interconnections between Inflammageing and Immunosenescence During Ageing

Abstract

Acute inflammation is a physiological response to injury or infection, with a cascade of steps that ultimately leads to recruitment of immune cells to clear invading pathogens and heal wounds. However, chronic inflammation arising from continued presence of the initial trigger, or dysfunction of signalling and/or effector pathways, is harmful to health. While successful ageing in older adults including centenarians is associated with low levels of inflammation, elevated inflammation increases the risk of poor health and death [1–3]. Hence inflammation has been described as one of seven pillars of ageing. Age-associated sterile, chronic, and low-grade inflammation is commonly termed inflammageing - it is not simply a consequence of increasing chronological age, but is also a marker of biological ageing, multimorbidity and mortality risk. While inflammageing was initially thought to be caused by “continuous antigenic load and stress”, reports from the last two decades describe a much more complex phenomenon also involving cellular senescence and ageing of the immune system. In this review, we explore the sources and consequences of inflammageing and highlight potential interventions. In particular, we assess the contribution of cellular senescence to age-associated inflammation, identify patterns of pro- and anti-inflammatory markers characteristic of inflammageing, describe alterations in the ageing immune system that lead to elevated inflammation, and finally assess the ways that diet, exercise and pharmacological interventions can reduce inflammageing and thus improve later life health.