Increased serum cathepsin S in patients with atherosclerosis and diabetes

Atherosclerosis and diabetes are closely associated and both involve extensive degradation of the aortic elastin. Increased elastase activity has been detected in diabetic animal aortae. We have demonstrated enhanced elastolytic cathepsin S in human atherosclerotic lesions but insufficient amounts of its endogenous inhibitor cystatin C, suggesting alterations of serum cathepsin S and/or cystatin C in patients with atherosclerosis or diabetes. In this study, we measured levels of both cathepsin S and cystatin C in sera from 240 patients by ELISA. Among these patients, 107 had a diagnosis of atherosclerotic stenosis, 103 were diabetic, and 30 had neither condition. Multiple linear regression analysis demonstrated that significantly higher serum levels of cathepsin S in patients with either atherosclerotic stenosis (p