Preeclampsia is associated with low circulating levels of insulin-like growth factor I and 1,25-dihydroxyvitamin D in maternal and umbilical cord compartments

Insulin-like growth factor I(IGF-I) stimulates renal and placental 1,25-dihydroxyvitamin D [1,25-(OH)(2)D] and is considered an important regulator of fetal growth. As 1,25-(OH)(2)D and birth weight are low in preeclampsia, this study was undertaken to determine whether circulating levels of IGF-I were associated with serum 1,25-(OH)(2)D concentrations in preeclamptic (PE group) and normotensive (NT group) pregnancies. Maternal and umbilical cord serum levels of IGF-I and 1,25-(OH)(2)D were significantly (P < 0.01) lower in the PE group than in the NT group. The concentrations of these two hormones correlated significantly in the umbilical cord (P < 0.05) and in the maternal (P < 0.001) compartments of the PE and NT groups, respectively. The amount of IGFBP-3 was 64% lower whereas that of IGFBP-1 was 2.9-fold higher in umbilical cord serum of the PE group compared with the NT group. In addition, maternal and umbilical cord serum IGF-I correlated significantly (P < 0.05) with weight and length at birth only in the PE group. In conclusion, the results of this study indicate that circulating IGF-I and 1,25-(OH)(2)D levels in both maternal and umbilical cord compartments are low in preeclampsia. Furthermore, this study suggests a differential regulatory effect of IGF-I on 1,25-(OH)(2)D synthesis and fetal growth depending on the presence or absence of preeclampsia.