Cord blood leptin and IGF-I in relation to birth weight differences and head circumference in monozygotic twins.
OBJECTIVE
To investigate a potential role of leptin and insulin-like growth factor (IGF)-I on fetal growth and metabolic function we determined plasma leptin and IGF-I concentrations in twins in relation to discordant fetal growth.


METHODS
In studying monochorionic twins with inter-twin birth weight difference, we investigated the relative contribution of genetic (fetus) versus environmental (maternal/placental) factors on growth. Thirty-six sets of twins (14 with discordant growth, birth weight difference >15%) who had been treated for severe twin-to-twin transfusion syndrome (TTTS) by laser coagulation were studied. Cord blood samples were collected at birth and analyzed for IGF-I and leptin. Inter-twin differences (delta) of birth weight and head circumference were correlated to delta hormone levels.


RESULTS
An inter-twin correlation for leptin (r = 0.69; p <0.0001) and delta IGF-I (r = 0.49; p <0.0001) was found. delta birth weight correlated significantly with delta IGF-I (r = 0.67; p <0.0001) but not with delta leptin (r = 0.23; p = 0.19). delta IGF-I concentrations did not correlate with delta leptin (r = 0.18). delta head circumference correlated significantly with delta leptin (r = 0.47; p <0.01) and with delta IGF-I (r = 0.46; p <0.01). Using a multiple regression model with head circumference as dependent variable, adjusted for gestational age, head circumference remained significantly associated with higher leptin concentrations in all patients (p = 0.03).


CONCLUSIONS
IGF-I is a good indicator for fetal growth and brain development. Leptin seems to be mainly genetically determined but may play a role in fetal brain development and is not only an index for fetal fat mass.
Gohlke
Bettina C
BC
Departments of Pediatrics, University of Bonn, Germany. Gohlke-Bonn@t-online.de
Huber
Agnes
A
Bartmann
Peter
P
Fimmers
Rolf
R
Hecher
Kurt
K
Bouret
Sebastien G
SG
Roth
Christian L
CL
D000886:Anthropometry; D001724:Birth Weight; D002508:Cephalometry; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D047109:Fetal Development / Q000502:physiology; D005317:Fetal Growth Retardation / Q000097:blood*; D005330:Fetofetal Transfusion / Q000097:blood / Q000378:metabolism* / Q000628:therapy; D005865:Gestational Age; D006257:Head / Q000254:growth & development; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D017075:Laser Coagulation; D020738:Leptin / Q000097:blood*; D009929:Organ Size; D011247:Pregnancy; D012016:Reference Values; D018709:Statistics, Nonparametric; D014430:Twins, Monozygotic / Q000097:blood*
D020738:Leptin; D007334:Insulin-Like Growth Factor I