Effect of reduced placental expression of zinc transporters on selective intrauterine growth restriction in monochorionic diamniotic twin pregnancies.

Zinc is an essential trace element. The regulatory mechanism of zinc and its transporters in fetal growth in monochorionic diamniotic (MCDA) twins with selective intrauterine growth restriction (MCDA-sIUGR) is unclear. A total of 45 MCDA twins were divided into two groups, MCDA (n=37) and MCDA-sIUGR (n=8), to investigate their possible effects on fetal growth. Maternal and fetal serum zinc levels were measured using a microassay. Immunohistochemistry and western blotting were performed to quantify the expression and localization of zinc transporters. Correlation scatter plots and matrices were used to test the correlation between maternal and cord serum zinc levels, placental zinc transporters, and fetal growth. There was a significant difference in fetal birth weight and placental weight among MCDA T (higher birth weight of twin), MCDA T (lower birth weight of twin), MCDA-sIUGR T and MCDA-sIUGR T groups (p<0.05), among which the MCDA-sIUGR T group was found to be significantly lower than the other three groups (p<0.05). Placental zinc transporters, including Zip 2, metal regulatory transcription factor 1 (MTF 1), and ZnT1, were significantly decreased in the MCDA-sIUGR T group compared to those in the other three groups (p<0.05). Furthermore, we observed varying degrees of correlation between fetal weight and maternal/fetal serum zinc levels and placental zinc transporters. Our study indicates that placental zinc transporters are impaired in MCDA-sIUGR, particularly in lightweight twins. Therefore, we hypothesized that the reduced placental expression of zinc transporters may affect fetal growth in MCDA twins.