Differential microscopic finding and glucose transporter 3 expression in terminal chorionic villi among birth weight-discordant twin placentas

Abstract

Objective: To evaluate differences in microscopic findings and glucose transporter 3 (GLUT3) expression in terminal chorionic villi (TV) among birth weight-discordant twin (BWDT) placentas compared with the birth weight-concordant twin (BWCT) placentas. Methods: We retrospectively studied a cohort of 26 BWDT, 10 BWCT, 10 pre-eclampsia singleton and 10 normal singleton pregnancies. Placentas were scored for the percentage of TV, the percentage of TV with syncytial knots, the presence of capillary branching patterns of TV, the capillary to terminal villous ratios, the membranous expression of GLUT3 and the nuclear expression of HIF-1α in trophoblasts and capillary endothelial cells of TV using immunohistochemistry. The clinical characteristics and microscopic findings were analyzed and compared. Results: BWDT placentas exhibited differential percentages of TV, percentages of TV with syncytial knots, capillary to terminal villous ratios, expression of HIF-1α in capillary endothelial cells and expression of GLUT3 in trophoblasts and capillary endothelial cells of TV among each twin pair compared with BWCT placentas (P=0.003, P=0.022, P=0.037, P=0.007, P=0.046 and P=0.002, respectively). Pre-eclampsia singleton placentas exhibited higher GLUT3 expression in trophoblasts, higher HIF-1α expression in capillary endothelial cells of TV and high capillary to terminal villous ratios compared with normal singleton placentas (P=0.001, P<0.001 and P=0.001, respectively). Conclusions: We observed a strong relationship between characteristics of adaptive change to hypoxia (GLUT3 expression, TV and syncytial knotting and higher capillary to terminal villous ratios) and BWDT pregnancy but not BWCT pregnancy.