Evaluation of plasma insulin-like growth factor-binding protein-3 as a potential predictor of preeclampsia

Elevated growth factor activity in women with preeclampsia is caused by an acid- and heat-labile protein complex with a native molecular mass of 150,000. The major plasma insulin-like growth factor-binding protein-3 has identical molecular characteristics. We hypothesized that increased endothelial cell release or decreased proteolytic degradation of insulin-like growth factor-binding protein-3 in preeclampsia would result in higher circulating levels of insulin-like growth factors and hence in increased mitogenic activity.

Plasma insulin-like growth factor-binding protein-3 concentrations were determined by iodine-125 insulin-like growth factor-II radioligand blots of nonreducing gels in 16 normal and 16 preeclamptic patients collected from a prospective, case-control study. Enzyme-linked immunosorbent assays also were performed with a specific anti-insulin-like growth factor-binding protein-3 antiserum.

Insulin-like growth factor-binding protein-3 concentrations were not different between women with normal versus preeclamptic pregnancies (p = 0.23). Enzyme-linked immunosorbent assays confirmed these results in a subset of patients.

The findings indicate that insulin-like growth factor-binding protein-3 concentrations do not account for the elevated mitogenic activity observed in plasma from women with preeclampsia and are not a useful screening test for preeclampsia risk.