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Abstract
Brain natriuretic peptide (BNP) is a cardiac hormone with diuretic, natriuretic, and vasodilator properties. Measurement of plasma B-type natriuretic peptide concentrations is increasingly used to aid diagnosis, assess prognosis, and tailor treatment in adults with congestive heart failure. Recent studies suggest that the peptide is also useful in pediatric patients. The diagnostic role of plasma BNP in neonates admitted to the NICU has shown promise as an aid in diagnosis in neonates with signs of congenital heart disease; as a biomarker of bronchopulmonary dysplasia, patent ductus arteriosus, and persistent pulmonary hypertension of the newborn; a predictive biomarker of the response to indomethacin in preterm infants; and, more significantly, in acute heart failure.
Keywords: brain natriuretic peptide (BNP); bronchopulmonary dysplasia (BPD); patent ductus arteriosus (PDA); persistent pulmonary hypertension of the newborn (PPHN)
RAIN NATRIURETIC PEPTIDE (BNP) IS a cardiac natriuretic hormone mainly produced by cardiomyocytes and has diuretic, natriuretic (substances secreted from the ventricles of the heart in response to changes in pressure that occur when heart failure develops and worsens), and vasodilatory properties (Figure l).1 In particular, BNP is produced by cardiac ventricular cells in response to volume expansion and increased pressure load such as in heart failure.2 So why not name the peptide "ventricular natriuretic peptide"? BNP is named as such because it was originally identified in extracts of porcine brain, although, in humans, it is produced mainly in the cardiac ventricles. Atrial natriuretic peptide (ANP) acts to reduce the water and sodium loads on the circulatory system, thereby reducing blood pressure.3
ANP and BNP are mainly synthesized in cardiac tissue; ANP in the atrium and BNP in the ventricle.4 Cardiac myocytes constitute the major source of BNP-related peptides, and the main stimulus for peptide synthesis and secretion is the myocyte stretch as might occur with congestive heart failure.5 These hormones are synthesized and released into the circulation by the atrial and ventricular myocytes in response to pressure overload, volume expansion, and increase in myocardial wall stress.6 ANP and BNP are measured in picograms per milliliter (pg/mL). A picogram is one trillionth of a gram (1.0 X 1012 grams). Plasma BNP concentrations in newborn infants are relatively high, vary greatly, and decrease rapidly during the first week of life. In children older...