Maternal–fetal transport kinetics of methotrexate in perfused human placenta:In vitrostudy

Unraveling the Mechanisms of Clinical Drugs-Induced Neural Tube Defects Based on Network Pharmacology and Molecular Docking Analysis

Chemotherapeutic agents such as methotrexate (MTX), raltitrexed (RTX), 5-fluorouracil (5-FU), hydroxyurea (HU), and retinoic acid (RA), and valproic acid (VPA), an antiepileptic drug, all can cause malformations in the developing central nervous system (CNS), such as neural tube defects (NTDs). However, the common pathogenic mechanisms remain unclear. This study aimed to explore the mechanisms of NTDs caused by MTX, RTX, 5-FU, HU, RA, and VPA (MRFHRV), based on network pharmacology and molecular biology experiments. The MRFHRV targets were integrated with disease targets, to find the potential molecules related to MRFHRV-induced NTDs. Protein-protein interaction analysis and molecular docking were performed to analyze these common targets. Utilizing the kyoto encyclopedia of genes and genomes (KEGG) signaling pathways, we analyzed and searched the possible causative pathogenic mechanisms by crucial targets and the signaling pathway. Results showed that MRFHRV induced NTDs through several key targets (including TP53, MAPK1, HSP90AA1, ESR1, GRB2, HDAC1, EGFR, PIK3CA, RXRA, and FYN) and multiple signaling pathways such as PI3K/Akt pathway, suggesting that abnormal proliferation and differentiation could be critical pathogenic contributors in NTDs induced by MRFHRV. These results were further validated by CCK8 assay in mouse embryonic stem cells and GFAP staining in embryonic brain tissue. This study indicated that chemotherapeutic and antiepileptic agents induced NTDs might through predicted targets TP53, MAPK1, GRB2, HDAC1, EGFR, PIK3CA, RXRA, and FYN and multiple signaling pathways. More caution was required for the clinical administration for women with childbearing potential and pregnant.

Contributions of Drug Transporters to Blood-Placental Barrier

The placenta is the only organ linking two different individuals, mother and fetus, termed as blood-placental barrier. The functions of the blood-placental barrier are to regulate material transfer between the maternal and fetal circulation. The main functional units are the chorionic villi within which fetal blood is separated by only three or four cell layers (placental membrane) from maternal blood in the surrounding intervillous space. A series of drug transporters such as P-glycoprotein (P-GP), breast cancer resistance protein (BCRP), multidrug resistance-associated proteins (MRP1, MRP2, MRP3, MRP4, and MRP5), organic anion-transporting polypeptides (OATP4A1, OATP1A2, OATP1B3, and OATP3A1), organic anion transporter 4 (OAT4), organic cation transporter 3 (OCT3), organic cation/carnitine transporters (OCTN1 and OCTN2), multidrug and toxin extrusion 1 (MATE1), and equilibrative nucleoside transporters (ENT1 and ENT2) have been demonstrated on the apical membrane of syncytiotrophoblast, some of which also expressed on the basolateral membrane of syncytiotrophoblast or fetal capillary endothelium. These transporters are involved in transport of most drugs in the placenta, in turn, affecting drug distribution in fetus. Moreover, expressions of these transporters in the placenta often vary along with the gestational ages and are also affected by pathophysiological factor. This chapter will mainly illustrate function and expression of these transporters in placentas, their contribution to drug distribution in fetus, and their clinical significance.

Effect of methotrexate administration on status of some essential trace elements and antioxidant enzymes in pregnant rats in late gestation

OBJECTIVE

Folate antagonists are widely used in the treatment of various cancerous states. Paucity of data on effect of administration of one such widely used drug, methotrexate (MTX), on the status of essential trace elements and antioxidant enzymes in pregnant women or in pregnant animals prompted us to undertake this study.

METHODS

MTX at a concentration of 5 mg/kg body weight was administered intraperitoneally as single dose to pregnant Sprague-Dawley rats for three consequitive days from day 17 of pregnancy. Control group of pregnant rats received single dose of saline instead of the anti-cancer drug on all the 3 days. After receiving the third dose of drug, the treated rats and control group rats were sacrificed, 1 h after intraperitoneal injection of a cocktail of essential trace elements namely, Cu, Se and Zn administered as a single bolus dose. Blood samples were collected 30 min of trace element cocktail injection, after decapitation and concentrations of trace elements in serum samples were determined by atomic absorption spectrophotometry. Concentrations of antioxidant enzymes, such as superoxide dismutase, glutathione peroxidase and total antioxidant status were determined by specific analytical kits, using spectrophotometry.

RESULTS

In control group(n = 6), serum concentrations of Cu, Se and Zn averaged 2330.5, 614.8 and 2773.2 microg/l, while in study group (n = 6) the concentrations of trace elements averaged 2294, 596 and 2713 microg/l, respectively. Student's t-test did not show any statistical significance (p > 0.05) between various trace element concentrations in control and treated groups. Cu:Zn ratios of control and treated group of rats did not vary significantly as well. Concentrations of superoxide dismutase, glutathione peroxidase in whole blood samples in control rats averaged 165 and 43,260 U/ml, respectively, while in MTX-treated group of animals the corresponding antioxidant enzymes averaged 330.6 and 67,101 U/ml respectively. SOD and GPX values were significantly higher in drug-treated animals compared to controls (Student's t-test, p < 0.05) However, total antioxidant activity was shown to be significantly lower (Student's t-test; p < 0.05) in the drug-treated group compared to control.

CONCLUSIONS

We report for the first time that effect of MTX administration in pregnancy is not associated with significant alteration in disposition of essential trace elements. However, the effect of drug administration on antioxidant enzyme status in pregnant women cannot be excluded while using the drug in clinical states.