Plasma amino-terminal pro C-type natriuretic Peptide in the neonate: relation to gestational age and postnatal linear growth.
BACKGROUND
C-type natriuretic peptide (CNP) plays an essential role in endochondral bone growth. Insight into CNP's paracrine actions is possible using plasma measurements of the amino-terminal pro C-type natriuretic peptide (NTproCNP). Whether correlations of NTproCNP with linear growth, as found in children and lambs, apply in neonates is unknown.


OBJECTIVE
Our objective was to determine the effects of prematurity, gender, and antenatal steroids on plasma NTproCNP at birth, and serial changes in hormone concentrations, linear growth, and markers of bone turnover in the first month of postnatal life.


METHODS
This is a prospective study of newborn infants admitted to an intensive care unit.


METHODS
A total of 48 infants (four gestation groups) were enrolled. Umbilical cord samples were also obtained from 39 healthy term infants.


METHODS
Plasma NTproCNP and CNP were measured in cord plasma. In enrolled neonates, serial measurements of hormone concentrations and markers of bone turnover were related to tibial growth velocity as measured by knemometry.


RESULTS
Cord plasma NTproCNP was inversely related to gestational age (r = -0.35; P = 0.003) and was higher in males (P < 0.001). Plasma NTproCNP (P = 0.016) and CNP (P < 0.001) increased within the first week of life, the increase relating inversely to gestational age (r = -0.64; P < 0.001). Plasma NTproCNP at 1 wk was strongly correlated with linear growth velocity (r = 0.49; P < 0.001), and also at 2-4 wk, the relation being stronger than observed between bone turnover markers and growth velocity.


CONCLUSIONS
In neonates with diverse disorders affecting growth and nutrition, plasma NTproCNP was strongly correlated with linear growth during the first 4 wk of postnatal life and may prove to be a novel marker of growth plate activity in neonates.
Prickett
Timothy C R
TC
Department of Medicine, Christchurch School of Medicine and Health Sciences, PO Box 4345, Christchurch Mail Centre, Christchurch 8140, New Zealand. tim.prickett@chmeds.ac.nz
Dixon
Bronwyn
B
Frampton
Chris
C
Yandle
Timothy G
TG
Richards
A Mark
AM
Espiner
Eric A
EA
Darlow
Brian A
BA
D001623:Betamethasone / Q000494:pharmacology; D001724:Birth Weight; D002657:Child Development / Q000502:physiology*; D015331:Cohort Studies; D024042:Collagen Type I / Q000097:blood; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005865:Gestational Age; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood* / Q000254:growth & development*; D007866:Leg / Q000502:physiology; D008297:Male; D020098:Natriuretic Peptide, C-Type / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood; D010455:Peptides / Q000097:blood; D011347:Procollagen / Q000097:blood; D011446:Prospective Studies; D018709:Statistics, Nonparametric
D024042:Collagen Type I; D005938:Glucocorticoids; D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen; C052929:collagen type I trimeric cross-linked peptide; C047202:procollagen Type I N-terminal peptide; D020098:Natriuretic Peptide, C-Type; D001623:Betamethasone