Activation of Ecto-5′-Nucleotidase in the Blood and Hearts of Patients With Chronic Heart Failure

Abstract Background Because plasma levels of adenosine are increased in patients with chronic heart failure (CHF), we examined adenosine concentrations in the plasma and heart and assessed the activity of ecto-5′-nucleotidase in the plasma and ventricular myocardium in patients with CHF. Methods and Results We studied 36 patients with CHF (New York Heart Association Class I/II/III/IV, 9/8/12/7). Twenty-five subjects without CHF were used as controls. Both plasma adenosine levels and ecto-5′-nucleotidase activity were significantly higher in patients with CHF (219 ± 28 nmol/L and 0.72 ± 0.03 nmoL/mg protein/min, respectively) than in control subjects (71 ± 8 nmol/L and 0.54 ± 0.02 nmoL/mg protein/min, respectively). Plasma adenosine levels sampled from the coronary sinus were significantly higher than from the aorta in patients with CHF, but these differences were not observed in control subjects. Ecto-5′-nucleotidase protein levels were markedly increased in the ventricular myocardium in patients with CHF. Conclusions These increases in ecto-5′-nucleotidase in the plasma and myocardium may contribute to increased plasma and cardiac adenosine levels. The increased ecto-5′-nucleotidase activity and adenosine levels in blood may become an index of the presence or severity of CHF.