The Role of the "Inflammatory/ Pathogen Burden" for Cardiac Ageing

In the elderly a chronic basal systemic inflammation prevails - which is evident by enhanced CRP or IL-6 plasma concentrations - and by compromised defense mechanisms against invading microbes. These alterations belong to the physiological ageing process of the immune system (immunosenescence) and are regarded as an inflammatory response towards lifelong antigen stress ("inflammatory/pathogen burden"). This lifelong antigen stress evokes an age-dependent basal inflammatory activation of innate immunity as well as a wasting of specific immunity: it is supposed that in the course of life-time due to a multitude of infectious/inflammatory events ("multiple hits") an inflammatory stress prevails or "inflammatory/pathogen burden" accumulates, which substantially contributes to an enhancement of the inflammatory parameters of natural immune response. Such enhanced inflammatory parameters characterize persons at increased risk of degenerative diseases like atherosclerosis or coronary heart disease. The risk is the higher, the higher the "pathogen burden". An impact of the inflammatory load on cardiac ageing has not yet been described. "CARDIAC AGEING", REFLECTED BY A NARROWING OF HEART RATE VARIABILITY: The physiological ageing process of the heart goes along with a narrowing of heart rate variability as shown by various groups, including our own. Arguments in favour of a causal relationship between inflammation and cardiac ageing come from an experimental study with healthy human volunteers who had received a low dose of endotoxin: such a proinflammatory stimulus leads to a reversible narrowing of heart rate variability (7). Also in senescence heart rate variability steadily declines, paralleled by a steady increase of basal inflammatory activity. The reduction of heart rate variability also is regarded as a sensitive parameter of autonomic dysfunction, which contributes to the compromise of cardiac reserve in old age. Apart from typical morphological features and funct