EVALUATION OF PLASMA INSULIN-LIKE GROWTH-FACTOR BINDING PROTEIN-3 AS A POTENTIAL PREDICTOR OF PREECLAMPSIA

OBJECTIVE: Elevated growth factor activity in women with preeclampsia is caused by an acid- and heat-labile protein complex with a native mo lecular mass of 150,000. The major plasma insulin-like growth factor-b inding protein-3 has identical molecular characteristics. We hypothesi zed that increased endothelial cell release or decreased proteolytic d egradation of insulin-like growth factor-binding protein-3 in preeclam psia would result in higher circulating levels of insulin-like growth factors and hence in increased mitogenic activity. STUDY DESIGN: Plasm a insulin-like growth factor-binding protein-3 concentrations were det ermined by iodine-125 insulin-like growth factor-II radioligand blots of nonreducing gels in 16 normal and 16 preeclamptic patients collecte d from a prospective, case-control study. Enzyme-linked immunosorbent assays also were performed with a specific anti-insulin-like growth fa ctor binding protein-3 antiserum. RESULTS: Insulin-like growth factor- binding protein-3 concentrations were not different between women with normal versus preeclamptic pregnancies (p = 0.23). Enzyme-linked immu nosorbent assays confirmed these results in a subset of patients. CONC LUSIONS: The findings indicate that insulin-like growth factor binding protein-3 concentrations do not account for the elevated mitogenic ac tivity observed in plasma from women with preeclampsia and are not a u seful screening test for preeclampsia risk.