Acute effects of beta-endorphin on cardiovascular function in patients with mild to moderate chronic heart failure

Background Cardiomyocytes produce opioid peptides and receptors. *-Endorphin is increased in the plasma of patients with congestive heart failure (CHF). We evaluated whether an intravenous infusion of *-endorphin exerted any effect on cardiovascular function and on the neurohormonal milieu in patients with mild to moderate CHF. Methods According to a double-blind, placebo-controlled design, 10 patients (5 men, age 46.9 * 8.2 years [mean * SD]) with CHF and New York Heart Association functional class II to III received, in random order, 1-hour intravenous infusion of *-endorphin (500 *g/h) and, on a separate occasion, received placebo and underwent echocardiographic and laboratory measurements at baseline and during infusions. Results *-Endorphin significantly increased left ventricular ejection fraction (LVEF) (P * .0001) and stroke volume (P * .0001), and reduced systemic vascular resistance (P * .031) in patients with CHF. These changes were paralleled by a significant increase in plasma levels of glucagon (P * .0001), GH (P * .0001), and IGF-1 (P * .0001), and a significant decrease in plasma levels of endothelin (P * .0001) and catecholamines (P * .01). No hemodynamic and neurohormonal changes were observed during the placebo study in any patient. Conclusions We conclude that a short-term, high dose infusion of *-endorphin improves LVEF, reduces systemic vascular resistance, blunts the neurohormonal activation, and stimulates the GH/IGF-1 axis in patients with mild to moderate CHF.