Simultaneous determination of plasma levels and cardiac expression of CNP in end-stage heart failure patients undergoing left ventricular assist devices

Purpose: Left ventricular assist devices (LVAD) implantation represents an alternative to heart transplantation, leading to a modification of neurohormonal profile and contributing to myocardial recovery. Few data are available about the involvement of C-type natriuretic peptide (CNP), and its specific receptor (NPR-B) during LVAD. The aim of the study was to evaluate the role of CNP in deteriorating HF patients undergoing LVAD implant, by the simultaneous determination of plasma levels and cardiac expression of both CNP and NPR-B. Methods: Seventeen LVAD patients (NYHA III- IV; LVEF<20%) were studied: 10 survived up to 1 month after LVAD (S) and 7 died of multiple-organ failure within 2 weeks (NS). Blood samples were obtained at admission (T1), at 4, 24, 72 hrs and 1, 2, 4 weeks (T2-T7) after LVAD implant. Cardiac biopsies were collected from left ventricle at time of heart transplantation. As controls, transplanted patients were enrolled. NT-proCNP plasma levels were measured by a direct immunometric assay. A RT-PCR analysis were performed to evaluate gene cardiac expression. Results: In S patients, after an initial increase of CNP levels, a reduction to basal levels was found 4 weeks post-LVAD, while in NS patients NT-proCNP sustained higher with a peak at 24 hrs and 72 hrs. A co-localization for CNP and NPR-B was showed in cardiac tissue of both LVAD and transplanted patients, although no significant difference in their mRNA expression was observed.