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

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.