Comparative study of insulin-like growth factor-I, insulin-like growth factor binding protein-3, and bone markers in pregnant normotensive and pre-eclamptic women

ABSTRACT

The current study was conducted to evaluate the serum OPG, RANKL and osteocalcin, as markers of bone turnover, in pre-eclamptic women compared to normotensive women, and to find out if there were any relationships between biochemical bone markers and IGF-1 and IGFBP-3. The present study included 30 women with pre-eclampsia as group I, GI. Thirty normotensive pregnant controls were included in the study representing group II, GII. All candidates of the study were subjected to routine laboratory investigations, serum IGF-l and IGFBP-3. Measurement of bone formation markers included serum alkaline phosphatase and serum calcium, and serum osteocalcin. Measurement of bone resorption markers included urinary hydroxyl proline, and newly discovered bone turnover markers which are serum osteoprotegerin [OPG] and serum RANKL. A significant decrease of serum alkaline phosphatase, calcium, OPG and IGF-1 were noted in the pre-eclamptic group when compared to the normotensive group. On the contrary, serum osteocalcin, RANKL, and IGFBP-3 showed a significant increase in the pre-eclamptic group when compared to the normotensive group. Bone formation and bone resorption markers showed a significant difference in pre-eclamptic women when compared to normotensive pregnant women. However, it is difficult to compare biochemical markers of bone turnover in this way because of differences in the specificity of the markers for bone and different metabolism by the liver and kidney in pre-eclamptic women. The high levels of biochemical markers may indicate increased bone turnover in the mother, but there could be some fetal contribution. Further studies are necessary to elucidate the detailed functions of OPG/RANKL on bone metabolism during pregnancy and pre-eclampsia