Serum prolidase activity in patients with cardiac syndrome X

OBJECTIVE: Although the underlying mechanism is not yet fully understood, Cardiac Syndrome X (CSX) is defined as microvascular dysfunction. Prolidase plays a role in collagen synthesis. Increased serum prolidase activity (SPA) has been shown to correlate with collagen turnover. Augmented collagen turn-over may be associated with vascular fibrosis and microvascular dysfunction. In this study, we assessed whether there was a correlation between CXS and prolidase activity. METHODS: This case-control study included 45 consecutive CSX patients (mean age 50.7 +/- 6.5 years, 27 women) and 40 healthy controls (mean age 51.2 +/- 6.5 years, 25 women). Prolidase activity was determined with the Human Xaa-Pro Dipeptidase/Prolidase enzyme-linked immunosorbent assay kit (Cusabio Biotech Co. Ltd, China). RESULTS: Mean prolidase activity was 898.8 +/- 639.1 mU/mL in the CSX group and 434.1 +/- 289.8 mU/mL in the control group (p<0.001). In ROC analysis, it was found that the SPA value above 350 mU/mL sympathizes with the diagnosis of CSX. CONCLUSION: Increased SPA in CXS patients may play an essential role in the pathophysiology of CSX, leading to augmented oxidative stress and vascular fibrosis, endothelial dysfunction, and increased microvascular resistance.