Plasma semicarbazide-sensitive amine oxidase is elevated in patients with congestive heart failure

Objective: Semicarbazide-sensitive amine oxidase (SSAO) is present in various mammalian tissues, especially in vascular smooth muscle cells, but also in plasma. The enzyme has been suggested to play a role in vascular endothelial damage through conversion of amines into cytotoxic aldehydes, ammonia and hydrogen peroxide. Endothelial dysfunction is present in diabetes mellitus (DM) and congestive heart failure (CHF). Elevated plasma SSAO activities have been reported in patients with DM, but no data on patients with CHF are as yet available. Methods and Results: Plasma SSAO was measured in 271 patients with CHF and compared to values in 77 controls. SSAO was found to be elevated in patients with CHF compared to controls (589 ± 252 vs. 455 ± 114 mU/l; P < 0.0001). Plasma SSAO was higher in NYHA class III/IV than in class III (662 ± 288 vs. 555 ± 226 mU/l; P = 0.004) and also higher in patients with concomitant DM than in those without (706 ± 248 vs. 557 ± 245 mU/l; P < 0.0001). Plasma SSAO correlated with plasma atrial natriuretic peptide (r = 0.42; P < 0.0001), with plasma norepinephrine (r = 0.27; P < 0.0001) and with left ventricular ejection fraction (r = -0.13; P = 0.0162). Multiple regression analysis showed atrial natriuretic peptide, norepinephrine, DM and cardiothoracic ratio to be the main determinants of plasma SSAO. Conclusion: The finding of elevated plasma SSAO in CHF, increasing with severity of the disease and with the concomitant presence of DM, supports the suggestion that SSAO may be involved in the pathogenesis of vascular endothelial damage. Plasma SSAO may be a useful parameter in assessing severity of CHF and in prognostic evaluation. Pharmacologic manipulation of SSAO activity might be an interesting new concept for prevention of vascular endothelial damage in various vascular disease entities.