Expression of ferritin receptor in placental microvilli membrane in pregnant women with different iron status at mid-term gestation

OBJECTIVE: The effect of iron status in pregnant women on expression of ferritin receptor in placental microvilli membrane at mid-term gestation was investigated. DESIGN: Ferritin receptor binding sites and dissociation constants (K(d)) were determined in specimens of placental microvilli from 30 pregnant women at mid-term gestation and six women at term-delivery. RESULTS: The ferritin receptor binding sites in the placental microvilli membrane in pregnant women with mild iron deficiency and moderate iron deficiency anemia were significantly higher then those in pregnant women with normal iron status. However, no significant difference was found between pregnant women with severe iron deficiency anemia and with normal measurements. No significant differences of K(d) values were detected between pregnant women with normal iron status and those with iron-deficiency. Data also revealed that the ferritin receptor binding sites in placental microvilli membrane and K(d) values at mid-term gestation did not differ significantly from those at term gestation. CONCLUSION: Lower iron status in pregnant women could lead to an increase in expression of ferritin receptor in placental microvilli membrane at mid-term gestation while the dissociation constant of ferritin receptor remains unchanged. This implies that the regulation of maternal-fetal iron homeostasis via the ferritin receptor-mediated pathway is achieved by changes in the numbers of ferritin receptors rather then binding properties.