Retinol-binding protein 4 in neonates born small for gestational age.
BACKGROUND
Retinol-binding protein 4 (RBP4) is an adipocyte-derived 'signal' that may contribute to the pathogenesis of insulin resistance and Type 2 diabetes. The relationship of RBP4 with insulin resistance and metabolic risk in human beings has been the subject of several studies. Subjects born small for gestational age (SGA) are at risk of insulin resistance and Type 2 diabetes. Though RBP4 could represent an early marker of insulin resistance, to date, none have determined RBP4 in SGA children.


OBJECTIVE
Our aim was to measure RBP4 concentrations in cord blood of SGA newborns compared with those in children born with a birth weight appropriate for gestational age (AGA) and to determine whether serum RBP4 levels at birth correlate with insulin sensitivity markers.


METHODS
Sixty-four newborns, 17 born SGA (mean gestational age: 36.4+/-2.1 weeks), and 47 born AGA (mean gestational age: 37.0+/-3.6 weeks) were studied. The main outcome measures included anthropometry, lipid profile, insulin, homeostasis model assessment, quantitative insulin-sensitivity check index, adiponectin, and RBP4.


RESULTS
RBP4 concentrations were significantly reduced in SGA newborns (p<0.002). No relationship was found between RBP4 and insulin sensitivity parameters. Stepwise regression analysis revealed that birth weight was the major predictor of RBP4 serum concentrations (p<0.001).


CONCLUSIONS
RBP4 is reduced in SGA newborns, birth weight representing the major determinant of RBP4 concentrations, and is not related to insulin sensitivity. No significant difference in adiponectin levels and insulin sensitivity markers was found between SGA and AGA neonates.
Giacomozzi
C
C
Molecular Endocrinology Unit, D.P.U.O. Bambino Gesù Children's Hospital, Rina Balducci Center of Pediatric Endocrinology, Tor Vergata University, Rome, Italy.
Ghirri
P
P
Lapolla
R
R
Bartoli
A
A
Scirè
G
G
Serino
L
L
Germani
D
D
Boldrini
A
A
Cianfarani
S
S
D052242:Adiponectin / Q000097:blood; D000328:Adult; D001724:Birth Weight; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D007236:Infant, Small for Gestational Age / Q000097:blood*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D054839:Retinol-Binding Proteins, Plasma / Q000378:metabolism*; D012307:Risk Factors
D052242:Adiponectin; D007328:Insulin; C101326:RBP4 protein, human; D054839:Retinol-Binding Proteins, Plasma