ABSTRACT
Background Coronary artery disease (CAD) cannot be sufficiently explained by the presence of traditional risk factors. Cathepsin D has been proposed to serve as a surrogate marker of atherosclerosis but its alterations in CAD patients have not been studied. Objective To evaluate serum cathepsin D concentrations in relation to the presence and severity of CAD. Materials and methods A total of 104 subjects were recruited; 71 patients with suspected CAD and 33 healthy subjects. Thirty-four patients had >50% coronary stenosis of at least one artery (CAD+); the remaining 37 patients had <50% stenosis (CAD−) based on angiography. CAD+ patients were sub-divided into three sub-groups with single (SVD; n = 15), double (2VD; n = 9), and triple vessel (3VD; n = 10) disease. Serum soluble cathepsin D concentrations were determined using an enzyme-linked immunosorbent assay (ELISA). Results Serum cathepsin D concentrations were significantly higher in the CAD+ compared with healthy control (p = 0.016) but not CAD− group (p = 0.098). Within the CAD+ group, patients with 3VD had significantly higher serum cathepsin D concentrations compared with the SVD group (p = 0.025), and also compared with the CAD− (p = 0.011) and SVD (p = 0.001) groups. No significant associations were found between serum cathepsin D concentrations and potential confounders including age, sex, blood pressure, smoking history and dyslipidemia. Conclusion Serum cathepsin D concentrations may be associated with the presence of CAD.