Apolipoprotein A-I-derived amyloid in atherosclerosis - Its association with plasma levels of apolipoprotein A-I and cholesterol

Wild-type apolipoprotein A-I (apo A-I)-derived amyloid commonly occurs in a therosclerotic plaques. To clarify apo A-I amyloid formation, plasma levels of apo A-I and cholesterol were related to the presence of amyloid in athe rosclerotic plaques in 15 patients with peripheral atherosclerosis, subject ed to arterial reconstruction. Plasma levels of apo A-I and high-density li poprotein (HDL) cholesterol were slightly higher in patients with apo A-I-d erived amyloid than in those without, but the difference was not significan t. Levels of low-density lipoprotein cholesterol and total cholesterol were significantly higher in the group with amyloid. High concentrations of apo A-I in the arterial intima are probably of greater importance to amyloid f ormation than high plasma levels of the protein. During atherosclerosis, th e acute phase reactant serum amyloid A may displace apo A-I from HDL, lendi ng to increased concentration of lipid-free apo A-I in the intima and confo rmational changes of apo A-I, which make if more fibrillogenic. Some forms of amyloid fibrils have been shown to be cytotoxic. Apo AI-derived amyloid is possibly a pathogenically important factor in atherosclerosis.