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This Article Full Text Full Text (PDF) All Versions of this Article: 296/6/R1744    most recent 00059.2009v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Boerrigter, G. Articles by Burnett, J. C. PubMed PubMed Citation Articles by Boerrigter, G. Articles by Burnett, J. C., Jr.

HEMODYNAMICS AND CARDIORENAL INTEGRATION

B-type natriuretic peptide 8-32, which is produced from mature BNP 1-32 by the metalloprotease meprin A, has reduced bioactivity

¹Cardiorenal Research Laboratory, Mayo Clinic and Mayo Clinic College of Medicine, Rochester, Minnesota; and ²Department of Cardiology, Helios-Klinikum, Erfurt, Germany

Submitted 27 January 2009 ; accepted in final form 15 April 2009

32-amino acid B-type natriuretic peptide (BNP 1-32) plays an important role in cardiovascular homeostasis. Recently, it was reported that BNP 1-32 is cleaved by the metalloprotease meprin A to BNP 8-32, the bioactivity of which is undefined. We hypothesized that BNP 8-32 has reduced vasodilating and natriuretic bioactivity compared with BNP 1-32 in vivo. Human BNP 8-32 and BNP 1-32 were compared in a crossover study in eight anesthetized normal canines. After a preinfusion clearance, BNP 1-32 was infused at 30 ng·kg^–1·min^–1 for 45 min followed by a 60-min washout and a second preinfusion clearance. Then, equimolar BNP 8-32 was infused. In half of the studies, the peptide sequence was reversed. Changes with peptides from the respective preinfusion clearance to infusion clearance were compared with paired tests. Mean arterial pressure was reduced by both BNP 8-32 and BNP 1-32 (–8 ± 3 vs. –6 ± 2 mmHg, P = 0.48). Changes in right atrial pressure, pulmonary capillary wedge pressure, heart rate, cardiac output, and glomerular filtration rate were similar. However, urinary sodium excretion increased less with BNP 8-32 than with BNP 1-32 (+171 ± 24 vs. +433 ± 43 µEq/min; P = 0.008), as did urinary potassium excretion, urine flow, and renal blood flow. While BNP 8-32 has similar vasodilating actions as BNP 1-32, its diuretic and natriuretic actions are reduced, suggesting a role for meprin A in the regulation of BNP 1-32 bioactivity in the kidney. Meprin A inhibition may be a potential strategy to increase the bioactivity of endogenous and exogenous BNP 1-32 in cardiovascular diseases.

hormone; peptidase; cardiorenal regulation; natriuretic peptides