Fetal concentrations of the growth factors TGF-α and TGF-β1 in relation to normal and restricted fetal growth at term.
Transforming growth factor-α (TGF-α) and TGF-β1 are major anti-inflammatory cytokines and substantially contribute to normal pregnancy outcome. TGF-α stimulates placental mitosis, whereas TGF-β1 is a critical regulator of trophoblast invasion and fetal growth. We aimed to study cord blood TGF-α and TGF-β1 concentrations in intrauterine-growth-restricted (IUGR, usually associated with abnormal trophoblast invasion, uteroplacental vascular insufficiency and enhanced inflammation) and appropriate-for-gestational-age-(AGA) pregnancies, and investigate possible correlations of the above concentrations with several demographic parameters of infants at birth. Plasma TGF-α and TGF-β1 concentrations were determined by ELISA in 154 mixed arterio-venous cord blood samples from IUGR (n=50) and AGA (n=104) singleton full-term infants. After controlling for possible confounding factors (gender, birth-weight, gestational age, maternal age and parity), cord blood TGF-α and TGF-β1 concentrations were significantly higher in IUGR than AGA group (b=0.402, SE=0.179, p=0.027 and b=0.152, SE=0.061, p=0.014, respectively). Delivery mode had an effect on cord blood TGF-α and TGF-β1 concentrations, both being elevated in cases of vaginal delivery (b=-0.282, SE=0.117, p=0.018 and b=-0.123, SE=0.059, p=0.038, respectively). In conclusion, higher cord blood TGF-α and TGF-β1 concentrations may represent a compensatory response to the inflammatory process characterizing the IUGR state. Additionally, higher cord blood TGF-β1 concentrations in IUGRs could be attributed to increased shear stress, resulting from abnormal blood flow in IUGR fetal blood vessels. Finally, vaginal delivery-associated cytokine release may account for elevated TGF-α and TGF-β1 concentrations.