Abstract 2495: Pharmacodynamic Profile of a Novel Chimeric Natriuretic Peptide, CD-NP, as Compared to C-Type Natriuretic Peptide

Abstract

Background: C-type natriuretic peptide (CNP), a 22-amino-acid peptide and a ligand of the natriuretic peptide receptor-B (NPR-B), exhibits venodilating, anti-fibrotic, and vascular-regenerating properties but limited renal actions. A Mayo-designed chimeric peptide, CD-NP, which consists of CNP and the C-terminus of Dendroaspis NP, was synthesized to test the hypothesis that CD-NP would possess CNP-like properties with an improved pharmacodynamic profile. Methods: Normal anesthetized dogs were given CD-NP 50 ng/kg/min (n = 10) or an equimolar dose of CNP 29.3 ng/kg/min (n = 9) i.v. for 75 min. Hemodynamic, renal, and hormonal data were obtained pre-infusion (pre-I), at 30 and 60 min I, and post-I, and were compared both within group vs pre-I (mean ± SE, P< 0.05*, < 0.01 † ) and between groups ( P < 0.05 ‡ , < 0.01 § , < 0.001 ¶ ). Plasma BNP was measured by radioimmunoassay. Results: CD-NP resulted in greater increases in plasma cGMP (7±.4 to 25±3 †¶ to 36±3 †¶ to 23±3 †¶ pmol/ml), urinary cGMP excretion (978±145, 3170±205 †¶ , 5919±616 †¶ , 3077±298 †¶ pmol/min) vs CNP (8±.8, 10±.6 † , 11±.7 † , 8±.5 pmol/ml; 976±110, 1104±115, 1317±103, 998±101 pmol/min, respectively). CD-NP also increased urine Na + excretion (19±4, 168±24 †§ , 237±26 †¶ , 96±12 † μEq/min), urine flow (0.2±.1, 1.3±.2 † , 1.8±.3 † , 0.8±.2 † ml/min), and GFR (37±2 ‡ , 48±3 † , 51±3 † , 53±4 † ml/min) vs CNP (36±12, 68±10, 85±26, 81±25 μEq/min; 0.4±.1, 0.9±.2, 1.2±.3*, 0.9±.3 ml/min; 52±5, 53±7, 50±4, 49±6 ml/min, respectively). CD-NP reduced PCWP (5.7±.7, 4.1±1*, 3.2±.7 † , 4.3±.8 mmHg), RAP (1.8±.4, 1.1±.4 † , 0.9±.5 †§ , 1.3±.5 § mmHg), PAP (12±.6, 10±.4*, 10±.6, 11±.7 mmHg) vs CNP (6±.6, 5±.8, 6±.8, 7±.9 † mmHg; 2.6±.3, 2.5±.3 to 2.9±.3 to 3.5±.5 † mmHg; 13±1, 12±1, 12±1, 13±1 mmHg, respectively). Mean blood pressure was unchanged in either group. CD-NP increased circulating BNP during infusion vs CNP (40±4 vs 18±2 pg/ml, P<0.001). Conclusion: This study demonstrates the successful transformation of CNP to a CNP-like peptide with enhanced natriuretic, diuretic, GFR-enhancing, and cardiac-unloading actions. CD-NP may also promote increases in plasma BNP which via the NPR-A receptor may contribute to its biological actions. The therapeutic potential of CD-NP in heart failure warrants further studies.