Comparison of the transport characteristics of bioactive substances in IUGR and normal placentas.
Knowing that IUGR is associated with altered placental transport, we aimed to characterize the placental transport of folic acid (FA), thiamine (THIAM), serotonin (5-HT), and 1-methyl-4-phenylpyridinium (MPP+) in IUGR. For this, we compared the transport characteristics of (3)H-FA, (3)H-THIAM, (3)H-5-HT, and (3)H-MPP+ in primary cultured human cytotrophoblasts isolated from IUGR and normal placentas (GRTB and NTB cells, respectively) and quantified mRNA expression of several placental transporters, by real-time RT-PCR. Our results show that GRTB cells take up (3)H-FA more efficiently (higher k(in) and A(max) values) and have higher transport capacity (higher V(max) values) for (3)H-FA, (3)H-5-HT, and (3)H-MPP+, when compared with NTB cells. In addition, GRTB cells take up (3)H-THIAM with higher affinity and (3)H-MPP+ with lower affinity than NTB cells. Finally, IUGR placentas have a generalized increase in mRNA expression of FA, THIAM, 5-HT, and MPP+ transporters, when compared with normal placentas, suggesting that the increase in transport capacity may be due to increased expression of placental transporters. These results point to an effect of "compensation for the weakness" of the IUGR placenta and pose the placenta as an active mediator of the communication between maternal and fetal environments.
Keating
Elisa
E
Department of Biochemistry (U38/FCT), Faculty of Medicine, University of Porto, Porto, Portugal. keating@med.up.pt
Gonçalves
Pedro
P
Costa
Fernanda
F
Campos
Isabel
I
Pinho
Maria João
MJ
Azevedo
Isabel
I
Martel
Fátima
F
D015655:1-Methyl-4-phenylpyridinium / Q000378:metabolism; D001692:Biological Transport; D002478:Cells, Cultured; D005260:Female; D005317:Fetal Growth Retardation / Q000378:metabolism*; D005492:Folic Acid / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism; D013831:Thiamine / Q000378:metabolism; D014327:Trophoblasts / Q000378:metabolism
D012333:RNA, Messenger; D012701:Serotonin; D005492:Folic Acid; D015655:1-Methyl-4-phenylpyridinium; D013831:Thiamine