Role of the IGF system in trophoblast invasion and pre-eclampsia

Insulin-Like growth factor-II (IGF-II) and IGF binding protein-1 (IGFBP-1) appear to play an important role in paracrine interactions at the maternal- fetal interface in human pregnancy. Patterns of expression of IGF-II and IG FBP-1 at the decidual-trophoblast interface suggest paracrine interactions occur between the IGF-II-expressing invading cytotrophoblast and maternal d ecidua-derived IGFBP-1. Autocrine/paracrine actions of trophoblast-derived IGF-II may be important in invasion, and for both trophoblast and decidual function. The actions of IGFBP-1 in binding IGF, and as an integrin Ligand, suggest it may have multiple roles in the interactions between the invadin g trophoblast and the maternal decidua, Abundant decidual IGFBP-1 may inter act with the IGF-II-expressing, protease-secreting trophoblast to modulate invasion. In-vitro studies of trophoblast-decidual cell interactions in inv asion, and clinical observations in a gestational disorder with shallow pla cental invasion such as preeclampsia, have provided new insights into the p ossible role(s) of IGFBP-1 in trophoblast invasion. The precise mechanisms underlying IGF and IGFBP-1 action at the decidual-trophoblast interface rem ain to be elucidated, The potential predictive value of serum IGFBP-1 conce ntrations in pre-eclampsia also remains to be established.