Circulating adrenomedullin is increased after heart transplantation

Objective: Adrenomedullin (ADM), secreted by the failing human heart, is a newly discovered potent endogenous vasorelaxing and natriuretic peptide tha t may play a role in cardiorenal regulation. No data are available on ADM i n heart-transplant recipients (Htx) and the aim of this study was to determ ine the short- and long-term responses of ADM after heart transplantation. Methods: Circulating ADM and its relationship with parameters of cardiovasc ular hemodynamics, humoral factors and renal function were determined in no rmal subjects and Htx early (1, 2, 4, 8, 15 and 30 days) and late (32+/-16 months) after transplantation. Additionally, ADM was obtained in matched hy pertensive and renal-transplant patients (n=9 in each group). Results: Plas ma ADM, elevated in heart failure patients, further increased transiently a t day 1 after transplantation (from 37.9+/-15.9 to 125.8+/-15.3 pmol/l, P<0 .01) and, although decreasing thereafter, remained elevated until the 30th day after transplantation (52.1+/-25.2 pmol/l). Late after transplantation, ADM concentrations were still increased compared to normal values (31.3+/- 5.3 vs. 19.4+/-2.7 pmol/l, P<0.001). ADM positively correlated with endothe lin, atrial natriuretic peptide (ANP) and cyclosporine. ADM was also correl ated with increased diastolic (r=0.68, P<0.04) and systolic (r=0.66, P<0.05 ) blood pressure in late Htx. No relationship was observed between ADM and left ventricular mass index, aldosterone and creatinine. ADM elevation was similar in hypertensive, renal-transplant patients and in Htx. Conclusions: Circulating ADM is increased after heart transplantation, in relation to h ypertension, endothelin, cyclosporine and ANP. In view of ADM's biological properties, these results might suggest a compensatory role for ADM against further development of vasoconstriction and fluid retention states after h eart transplantation. (C) 1999 Elsevier Science BN. All rights reserved.