Expression of insulin-like growth factor in the placenta of intrauterine growth-retarded human fetuses

Many cases of intrauterine growth retardation (IUGR) are the result of plac ental and fetal tissue insufficiency. Insulin-like growth factor-I (IGF-I) is known to play a role in placental and fetal growth. An immunocytochemica l study was performed to localize ICF-I peptides in human placenta and umbi lical cords of normal (n = 3) and IUGR (n = 3) fetuses. The peripartum feta l conditions were evaluated as well. Immunoreactive IGF-I was detected in t he cytotrophoblast, syncytiotrophoblast, amnion, endothelial cells of fetal capillaries and in the decidua in both normal and IUGR placental tissue. A more robust immunostaining and increased numbers of positively stained cel ls were found in the decidua of IUGR placenta (p < 0.001). Intense immunost aining was also found in endothelial cells, smooth muscle cells and fibrobl asts of the umbilical vein. IGF-I immunoreactivity was also present in stro ma (Hofbauer cells and/or fibroblasts) of IUGR villi; Our results indicate that expression of IGF-I is high in specific sites in placenta and umbilica l cords, which indicates a paracrine and/or endocrine function. The increas ed expression of IGF-I in placenta of IUGR fetuses indicates its involvemen t in restoring normal growth by means of a positive feed-back mechanism.