The role of inflammation and infection in acute coronary syndrome

Inflammatory process within the vessel wall is considered to be crucial for initiation and progression of atherosclerosis. As response to endothelial injury a focal inflammatory response arises which can lead to plaque vulnerability and rupture and a consecutive acute coronary syndrome. Systemic markers of inflammation like C-reactive proteine (CRP) or interleukin (IL) 6 are elevated in stable angina and acute coronary syndrome and are associated with future cardiovascular events even in initially healthy people. Alongside classical risk factors infectious agents like cytomegalovirus or Chlamydia pneumoniae are discussed to be involved in the local and systemic inflammatory response. Seroepidemiological studies revealed disparate results of the association between antibody titers against Chlamydia pneumoniae or cytomegalovirus and prevalence of coronary artery disease or future cardiovascular events. In animal models Chlamydia pneumoniae and cytomegalovirus increase accelerated neointimal response, however, molecular mechanisms are not entirely clear. Conclusion: Whereas local and systemic inflammatory processes play a crucial role in atherogenesis and prognosis the causal role of infection in atherogenesis remains controversial.