Autoimmunity, oxidized LDL and cardiovascular disease

Atherosclerosis is the major cause of cardiovascular disease (CVD) and in addition to established risk factors as smoking, hypertension, diabetes and dyslipidemia, inflammation and autoimmune reactions have been much discussed recently. Several lines of evidence indicate that also inflammation and autoimmune reactions are highly relevant in atherosclerosis and CVD. Inflammatory cells and cytokines are present in lesions, already at an early stage; animal experiments suggest that immune reactions, though not necessary for development of atherosclerosis, can modulate disease development and systemic inflammation is associated with an enhanced risk of CVD. The enhanced risk of CVD in a major autoimmune disease, systemic lupus erythematosus (SLE), is therefore highly relevant, and in addition to being an important clinical problem, SLE-related CVD could give insights into the nature of autoimmunity in atherosclerosis and CVD in general. We recently defined traditional and non-traditional risk factors for CVD in SLE. These include increased atherosclerosis (as determined by intima-media thickness of carotid artery); raised oxidized low density lipoprotein (OxLDL) and autoantibodies to OxLDL; dyslipidemia with raised triglycerides and Lp(a) and decreased HDL-cholesterol concentrations; raised systemic inflammation; presence of anti-phospholipid antibodies including lupus anticoagulant, homocysteine-levels and more frequent osteoporosis. Disease duration, smoking, blood pressure or diabetes mellitus did not differ significantly between the groups. Taken together, immune reactions are highly relevant in atherosclerosis, and patients with autoimmune disease like SLE are at high-risk of CVD. If confirmed prospectively, non-traditional risk factors like OxLDL in the circulation, autoantibodies against OxLDL and phospholipids and inflammation could lead to new therapeutic strategies and insight into disease mechanisms.