Immunohistochemical Study of Transferrin Receptor Expression in the Placenta of Pre-eclamptic Pregnancy

Transport of iron from the mother to the fetus is essential for the normal development of the fetus and abnormalities in the transferrin receptor (TFR) on the placental trophoblasts might have some crucial effects on the fetal iron metabolism. The present study was undertaken to determine whether there are any changes in the expression of the transferrin receptor in the placenta from pre-eclamptic mothers. An immunohistochemical study using antibodies specific for C-terminus and N-terminus regions of the TFR revealed that TFR expression by syncytiotrophoblasts around chorionic villi is markedly reduced in placentae from pre-eclamptic pregnancies compared to those from normal pregnancies and pregnancies at early gestational age that terminated by abortion. The same result, although to a lesser extent, was obtained even in trophoblasts which were located around atrophic villi with fibrotic changes in the interstitium, or which invaded into the deciduas. The expression of human chorionic gonadotropin (HCG) on those cells was observed to the same extent in the normal and pre-eclamptic pregnancy groups. The concentration of TFR in the peripheral blood also decreased in pre-eclampsia. These results suggest that TFR synthesis in the pre-eclampsia, especially in the placental trophoblasts, is decreased.