C-reactive protein - biological functions, cardiovascular disease and physical exercise

Abstract

C-reactive protein (CRP) is an acute-phase reactant that increases in response to noxious stimuli that inevitably induce cellular and/or tissue injury. The increased synthesis of CRP occurs predominantly in the liver and peaks 24 - 48 hours after the inciting stimulus. CRP forms an integral component of innate immunity and serves primarily to recognise potential pathogens and damaged cells. It facilitates the removal of these cells through opsonisation and activates the complement system. With increasing evidence supporting the classification of artherosclerosis as inflammatory in nature, CRP has received considerable attention as a marker, and in some cases a contributor towards this cardiovascular disease. Traditionally, CRP has been measured within exercise studies to provide evidence that an acute-phase inflammatory response can or has been initiated. Although the elevation in CRP following exercise has largely been attributed to muscle damage, evidence is mounting to contest this premise. Participation in chronic exercise has been associated with a reduced risk of cardiovascular disease. Numerous studies have now shown an inverse relationship between physical activity levels and resting concentrations of CRP. Thus, exercise may prove beneficial in lowering systemic inflammatory markers such as CRP, and consequently contribute towards preventing the progression of inflammatory disorders. South African Journal of Sports Medicine Vol. 18 (1) 2006: pp. 24-28