Metoprolol Improves Endothelial Function in Patients with Cardiac Syndrome X

Endothelial dysfunction which is manifested by the loss of nitric oxide bioavailability, is an
increasingly recognized cause of cardiac syndrome X (CSX) and beta blockers are used for the
treatment of this syndrome. Thus, the aim of this study was to investigate effects of metoprolol,
as a beta blocker, on endothelial function in CSX patients.
The study included 25 CSX patients (20 female/ 5 male, mean age: 55.36± 10.31 years) who
received metoprolol (50 mg BID) for one month. In addition, 25 healthy controls (20 female/
5 male, mean age: 54.32 ± 9.27 years) were enrolled. Levels of endothelin-1, E-selectin, and
vascular cell adhesion molecule-1 (VCAM-1) in controls and CSX patients were measured,
both at the baseline and after the treatment, by the enzyme-linked immunosorbent assay. In
CSX patients, at the baseline, levels of E-selectin and VCAM-1 were signifcantly higher than
those of the controls. In addition, levels of these biomarkers in CSX patients after the treatment
signifcantly decreased compared to the baseline. In spite of similar tendency, these differences
were not signifcant for endothelin-1. In conclusion, metoprolol therapy improves endothelial
function. Thus, it may be a suggested choice for CSX treatment. However, further studies are
needed to confrm the clinical signifcance of metoprolol therapy for CSX patients.