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Introduction: Research in animal models and preliminary clinical studies in humans support the use of pravastatin for the prevention of preeclampsia. However, its use during pregnancy is still controversial due to limited data about its effect on the human placenta and fetus., Methods: In the present study, human placental cotyledons were perfused in the absence or presence of pravastatin in the maternal reservoir (PraM). In addition, placental explants were treated with pravastatin for 5, 24 and 72 h under normoxia and hypoxia. We monitored the secretion of placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin (sEng), endothelial nitric oxide synthase (eNOS) expression and activation and the fetal vasoconstriction response to angiotensin-II., Results: The concentrations of PlGF, sFlt-1 and sEng were not significantly altered by pravastatin in PraM cotyledons and in placental explants compared to control. Under hypoxic conditions, pravastatin decreased sFlt-1 concentrations. eNOS expression was significantly increased in PraM cotyledons but not in pravastatin-treated placental explants cultured under normoxia or hypoxia. eNOS phosphorylation was not significantly affected by pravastatin. The feto-placental vascular tone and the fetal vasoconstriction response to angiotensin-II, did not change following exposure of the maternal circulation to pravastatin., Conclusion: We found that pravastatin does not alter the essential physiological functions of the placenta investigated in the study. The relevance of the study lays in the fact that it expands the current knowledge obtained thus far regarding the effect of the drug on the normal human placenta. This data is reassuring and important for clinicians that consider the treatment of high-risk patients with pravastatin, a treatment that exposes some normal pregnancies to the drug.

Objective: Drugs of abuse affect pregnancy outcomes, however, the mechanisms in which cannabis exerts its effects are not well understood. The aim of this study was to examine the influence of short-term (1-2 hours) exposure to cannabidiol, a major phytocannabinoid, on human placental breast cancer resistance protein function., Study Design: The in vitro effect of short-term exposure to cannabidoil on breast cancer resistance protein in BeWo and Jar cells (MCF7/P-gp cells were used for comparison) was tested with mitoxantrone uptake, and nicardipine was used as positive control. The ex vivo perfused cotyledon system was used for testing the effect of cannabidoil on glyburide transport across the placenta. Glyburide (200 ng/mL) was introduced to maternal and fetal compartments through a recirculating 2 hour perfusion, and its transplacental transport was tested with (n = 8) or without (n = 8) cannabidoil., Results: (1) Cannabidoil inhibition of breast cancer resistance protein-dependent mitoxantrone efflux was concentration dependent and of a noncell type specific nature (P < .0001); (2) In the cotyledon perfusion assay, the administration of cannabidoil to the maternal perfusion media increased the female/male ratio of glyburide concentrations (1.3 ± 0.1 vs 0.8 ± 0.1 at 120 minutes of perfusion, P < .001)., Conclusion: (1) Placental breast cancer resistance protein function is inhibited following even a short-term exposure to cannabidoil; (2) the ex vivo perfusion assay emphasize this effect by increased placental penetration of glyburide to the fetal compartment; and (3) these findings suggest that marijuana consumption enhances placental barrier permeability to xenobiotics and could endanger the developing fetus. Thus, the safety of drugs that are breast cancer resistance protein substrates is questionable during cannabis consumption by pregnant women., (Copyright © 2013 Mosby, Inc. All rights reserved.)

Objective: To evaluate the effect of magnesium sulfate (MgSO(4)) on placental expression levels of vascular endothelial growth factor (VEGF)., Materials and Methods: Cotyledons of term normotensive and preeclamptic placentas were dually perfused for 6 h, with MgSO(4) (6-7 mg%) in the maternal reservoir [normotensive (n = 3); preeclamptic (n = 4)] and with the control medium (without MgSO(4)) [normotensive (n = 3); preeclamptic (n = 6)]. After perfusion, placental tissue samples were collected from four different placental compartments (amnion, chorion, placental villous and decidua). The collected placental tissues were homogenized and examined for VEGF by ELISA. Statistical significance was determined using a two-way analysis of variance., Results: After perfusion with control medium, significantly lower levels of VEGF were detected in the chorion and placental villous compartments of preeclamptic placentas (70 ± 24 pg/g protein and 29 ± 11 pg/g protein; respectively), as compared with normotensive placentas (172 ± 80 pg/g protein and 51 ± 17 pg/g protein; respectively; p < 0.05). Exposure of preeclamptic placentas to MgSO(4) resulted in decreased VEGF levels by the amnion (57 ± 26 pg/g protein), as compared with the control group (153 ± 62 pg/g protein) (p < 0.05). On the other hand, MgSO(4) significantly increased VEGF levels by the placental villous and the decidua (58 ± 15 pg/g protein, 70 ± 29 pg/g protein; respectively), as compared with the control group (29 ± 11 pg/g protein, 33 ± 14 pg/g protein; respectively) (p < 0.01, p < 0.05; respectively). Exposure to MgSO(4) did not affect VEGF levels in normotensive placentas., Conclusion: Reduced levels of VEGF are expressed by some placental compartments in preeclampsia compared with normotensive pregnancy. Perfusion with MgSO(4) affects VEGF expression differently by preeclamptic and normotensive placentas. Increased production of placental VEGF in preeclampsia may play a role in the therapeutic action of MgSO(4).

Objective: To examine the effect of magnesium sulfate (MgSO(4)) on sFlt (soluble fms-like tyrosine kinase)-1 in the fetal and maternal compartments of normotensive and preeclamptic placentas., Methods: Cotyledons of term normotensive and preeclamptic placentas were dually perfused for six hours, with control medium and MgSO(4) (6-7 mg %) in the maternal reservoir. Perfusate sFlt-1 concentrations were measured., Results: Median sFlt-1 concentration was higher in the maternal than in the fetal side in both groups and perfusion media (p < 0.0001). When perfused with control medium, the maternal side median sFlt-1 concentration was higher in the preeclampsia than in the control group (p < 0.0001). After perfusion with MgSO(4), the median maternal and fetal sides perfusate sFlt-1 concentration were higher in the preeclampsia than in the control group (p < 0.0001). In comparison to perfusion with control medium, the median sFlt-1 concentration of normal pregnant women decreased in the fetal and increased in the maternal side. In the preeclampsia group, only median fetal side sFlt-1 concentration increased., Conclusion: In contrast to normal pregnant women, perfusion with MgSO(4) of preeclamptic placentas did not increase their sFlt-1 concentration. This may indicate that MgSO(4) role may be limited to its anti-eclamptic and does not affect the anti-angiogenic state associated with preeclampsia.

Preeclampsia is a pregnancy-specific disorder characterized by hypertension and systemic endothelial dysfunction. Interleukin (IL)-1β is a possible mediator of maternal endothelial dysfunction in preeclampsia. Serum IL-1β as well as its natural inhibitor IL-1 receptor antagonist (IL-1Ra) were reported to be increased in women with preeclampsia. In the current study, we addressed the role of the placenta in controlling the circulatory levels of IL-1β and its natural inhibitor IL-1Ra in preeclampsia, and the possible effect of magnesium sulfate (MgSO(4)) on these levels. Using an ex vivo placental perfusion system, placentas from preeclamptic (n = 9) and normotensive (n = 6) pregnancies were perfused in presence or absence of MgSO(4). Perfusate samples were collected from the maternal and the fetal circulations of the perfusion system, and IL-1β and IL-1Ra were examined by enzyme-linked immunoassay (ELISA). Preeclamptic placentas secreted higher levels of IL-1β (P < 0.001), and a tendentious higher levels of IL-1Ra, mainly into the maternal circulation, as compared with normotensive placentas, although no differences in IL-1β:IL-1Ra ratio were detected. However, there was only tendentious increase in the secretion levels of IL-1β or IL-1Ra into the fetal circulation of preeclamptic placentas, when compared with normotensive placentas. Administration of MgSO(4) to preeclamptic placentas resulted in an attenuation of the increased secretion of IL-1β into the maternal circulation (P < 0.001), and in a tendentious reduction in IL-1Ra. However, IL-1β:IL-1Ra ratio in preeclamptic placentas was not affected by MgSO(4). Interestingly, exposure of normotensive placenta to MgSO(4) resulted only in increased levels of IL-1Ra in the maternal circulation, without affecting IL-1β levels or IL-1β:IL-1Ra ratio. These findings suggest that the placenta may contribute to the elevation in serum IL-1β and IL-1Ra in preeclampsia by increased secretion of these cytokines into the maternal circulation, and that MgSO(4) is able to attenuate this increased secretion of IL-1β, and possibly IL-1Ra, in preeclampsia.

It has become clear that almost any drug or chemical substance administered to the mother is able to cross the placenta to some extent, unless it is metabolized or altered during passage, or else its molecular size and low lipid solubility do not allow transplacental transfer. A number of transport systems have been identified in the placenta, which recognizes a wide variety of pharmacological active drugs as substrates. In recent years, research on human placental transporters has been developing due to the increase of knowledge technology in pharmacology. In this review we will focus on the main placental transporters which are known today. The P-glycoprotein (P-gp), Breast cancer resistance protein (BCRP/ABCG2) and Multidrug resistance associated protein 2 (MDR2) transporters are expressed at the apical surface of the syncytiotrophoblast, and have a protective effect. Transporters for 5-HT (SERT) and NE (NET) are also expressed at the apical surface and regulate extracellular concentrations of monoamines. The physiologic function of Multidrug resistance associated protein (MRP) transporters (which is expressed at the basal surface of the syncytiotrophoblast) may be the removal of metabolic end products from the fetus. Some of the members of the organic anion transporters are also expressed at the basolateral surface of the syncytiotrophoblast.

Objective: The present study was aimed to compare term versus preterm placental pathologies associated with fetal growth restriction (FGR)., Study Design: A retrospective cohort study was performed, including all singleton deliveries of FGR with placental pathology examination. Comparison of placental findings was performed between neonates who were born at term versus preterm. Preterm was defined as <37 completed weeks of gestation, and <34 weeks gestation in another analysis. When one or more of the following pathology was found in microscopic examination of the placental tissue, the term uteroplacental insufficiency was defined: placental infarct, fibrosis of chorionic villi, thickening of blood vessels and poor vascularity of the chorionic villi., Results: Macroscopic placental findings were available for 1,104 singleton FGR neonates; of these, 395 placentas had microscopic examinations. A significant greater proportion of preterm FGR cases had pathology findings associated with uteroplacental insufficiency as compared to term FGR (29.4 vs. 36.7%; OR = 1.4 95%, CI = 1.05-1.9; P = 0.019). The same pattern was seen while comparing placentas of FGR neonates who were born before and after 34 weeks (32.4 vs. 39.4%; OR = 1.4, 95% CI 1.02-1.8; P = 0.028). Syncytial knots were significantly more common in placentas from neonates who were delivered before 34 weeks of pregnancy (15.2 vs. 6.3%; OR = 2.6, 95% CI 1.3-5.6; P = 0.005). This trend was not statistically significant while comparing FGR before and after 37 weeks gestation (10.9 vs. 4.6%; OR = 2.4, 95% CI 0.99-7.7; P = 0.052). Meconial impregnation was more common among term versus preterm FGR neonates <37 weeks (22.4% vs. 7.2% OR = 3.7, 95% CI 2.3-5.9; P < 0.001), as well as among neonates who were born before and after 34 weeks of gestation (14.5 vs. 5.9%; OR = 0.4, 95% CI 0.2-0.6; P < 0.001)., Conclusions: Placentas of preterm FGR neonates (either <37 weeks or <34 weeks gestation) reveal numerous pathologies reflecting uteroplacental insufficiency and abnormal blood supply. The presence of increased syncytial knots in preterm FGR neonates is probably due to exposure to hypoxia and reactive oxygen agents.

Interleukin-6 (IL-6) is one of the main proinflammatory mediators of hypertension and endothelial dysfunction in preeclampsia. In this study, we investigated the capacity of the preeclamptic placenta to secrete IL-6 and the effect of magnesium sulfate (MgSO(4)) on it. Placentas from normotensive (37-40 weeks) and preeclamptic (36-40 weeks) pregnancies were dually perfused for 6 h in the absence [normotensive (n = 3); preeclamptic (n = 4)] and presence [normotensive (n = 3); preeclamptic (n = 4)] of MgSO(4). Perfusate samples from the maternal and the fetal circulations were collected at each 30 min throughout the perfusion period and examined for IL-6 by enzyme-linked immunoassay. Statistical analysis was performed using the 2-way analysis of variance. In the absence of MgSO(4), IL-6 levels in the maternal and the fetal circulations of preeclamptic placentas (4.2 ± 1.3 and 0.9 ± 0.5 pg/mL/g cotyledon; respectively) were significantly higher, when compared with normotensive placentas (1.9 ± 0.5 and 0.2 ± 0.2 pg/mL/g cotyledon; respectively) (P < 0.05). Addition of MgSO(4) to the perfusate of normotensive placentas did not affect IL-6 secretion. However, exposure of preeclamptic placentas to MgSO(4) resulted in decreased IL-6 levels in the maternal circulations (1.7 ± 0.3 pg/mL/g cotyledon), when compared with the control group (P < 0.05). In the fetal circulation, the addition of MgSO(4) resulted only in a nonstatistical significant tendency toward decreased IL-6 levels, when compared with the control group. Our findings indicate that the perfused preeclamptic placenta secretes increased levels of IL-6 into the fetal and the maternal circulations and that MgSO(4) may normalize these increased secreted IL-6 levels.

Objective: To determine the role of BCRP in nitrofurantoin (NF) transport in JAr cells and the possible contribution of OATP2B1, P-gp and MRPs to this transport., Methods: Cells were incubated with various BCRP, P-gp, MRPs, organic anion transporting polypeptide (OAT) and OATP2B1 inhibitors for 15 min, followed by incubation for 30 min with NF, with or without the inhibitors mentioned earlier. NF cytotoxicity was examined using neutral red (NR) assay. Intracellular NF levels were analyzed by HPLC., Results: NR assay showed that incubation conditions with NF (as carried out in our experiments) were not cytotoxic. Incubation with specific inhibitors of BCRP (FTC, Chrysin and Novobiocin), showed a significant increase in NF accumulation in the cells. Inhibitors of OATP2B1 (EGCG and BSP) had no influence on NF accumulation. Specific inhibitors of P-gp and MRPs (Verapamil and Indomethacin, respectively) also had no influence on NF accumulation in JAr cells., Conclusions: NF is probably a specific substrate of BCRP, and BCRP has a major active role in NF transport in JAr cells. For the first time, we showed, that P-gp, MRPs, and the OATP2B1, probably have a negligible contribution to NF transport in JAr cells.

Objective: To examine the effect of magnesium sulfate (MgSO(4)) on tumor necrosis factor-alpha (TNF-alpha) secretion by preeclamptic placentas., Study Design: Cotyledons of six, term, normotensive and ten, pre-eclamptic placentas were dually perfused for six hours (6h), with MgSO(4) (6-7 mg %) in the maternal reservoir [normotensive (n = 3); pre-eclamptic (n = 5)], and with control medium (without MgSO(4)) [normotensive (n = 3); pre-eclamptic (n = 5)]. Perfusate samples from the maternal and the fetal circulations were collected every 30 min throughout the 6h of perfusion, and examined for TNF- alpha levels using ELISA. Statistical significance was determined using a 2-way analysis of variance., Results: Pre-eclamptic placentas perfused with control medium (without MgSO(4)) secreted higher levels of TNF-alpha into the fetal and the maternal circulations (1.60 +/- 0.59 pg/mL/g of cotyledon and 14.28 +/- 2.69 pg/mL/g of cotyledon, respectively), as compared to the fetal and maternal circulations of normotensive placentas (0.25 +/- 0.09 pg/mL/g of cotyledon and 6.73 +/- 1.11 pg/mL/g of cotyledon, respectively) (p < 0.01). Addition of MgSO(4) to normotensive placentas did not affect TNF-alpha levels in the fetal or maternal circulations. However, exposure of pre-eclamptic placentas to MgSO(4) significantly decreased TNF-alpha levels in both the fetal (0.89 +/- 0.09 pg/mL/g of cotyledon versus 1.6 +/- 0.59 pg/mL/g of cotyledon; p < 0.05) and the maternal circulations (4.74 +/- 2.78 pg/mL/g of cotyledon versus 14.28 +/- 2.69 pg/mL/g of cotyledon; p < 0.01)., Conclusion: Down-regulation of placental TNF-alpha secretion by MgSO(4) in pre-eclampsia might indicate a possible therapeutic effect for this agent in reducing maternal, endothelial dysfunction and in improving neonatal outcome in pre-eclampsia, by reducing TNF-alpha levels in maternal and fetal circulations.

Background: One of the most important hormones synthesized by the placenta during pregnancy is progesterone. The regulating mechanisms of progesterone synthesis and the mechanism responsible for the spontaneous onset of labor in women are still not fully understood. Progesterone is thought to have been involved in human parturition. The objective of this study was to compare the levels of progesterone in the human placentas, at the end of the gestation (37-41 weeks) in vaginal versus cesarean deliveries, and to evaluate the pattern of progesterone accumulation, instantly following its synthesis by the human placenta at the end of the pregnancy., Methods: Progesterone levels in human placental tissue were determined by immunochemiluminescent analysis, following tissue homogenization. Progesterone secretion and accumulation pattern in the placental tissue was demonstrated using the ex vivo, closed, dual perfusion system of isolated human placental cotyledon., Results: Immunochemiluminescent analysis of progesterone levels in human normal and cesarean-delivered placentas showed that placentas following normal vaginal delivery store higher concentrations of progesterone, and produce progesterone more intensively. Results obtained from 120-min perfusions (of vaginal and cesarean-delivered placentas) showed that progesterone tended to accumulate in the maternal rather than the fetal compartment., Conclusions: These data indicate that progesterone levels continuously rise till the end of pregnancy, with no apparent drop in progesterone levels during the labor process. In addition, progesterone is released from the syncytiotrophoblast preferably into the maternal component of the placental tissue.

Purpose: To compare the placental pathologies and perinatal outcomes in fetal growth restriction (FGR) pregnancies with and without oligohydramnios., Methods: A retrospective cohort study, comparing placental findings in all singleton deliveries with FGR., Results: Macroscopic placental findings were available for 1,104 singleton FGR pregnancies. A total of 397 placentas were microscopically examined; of which 89 placentas were of FGR neonates who had oligohydramnios. No significant differences in placental vascular mal-perfusion were found between pregnancies with and without oligohydramnios (69.3 vs. 74.3%; P = 0.357). Likewise, no significant differences were noted between the groups regarding diffuse villous fibrosis (10.1 vs. 4.9%; P = 0.573), and amnion cell metaplasia (65.9 vs. 64.3%; P = 0.779). Cases of FGR complicated with oligohydramnios had significantly higher rates of perinatal mortality (9.9 vs. 5.9%; P = 0.028), preterm deliveries (34.9 +/- 3.4 vs. 35.4 +/- 3.1 weeks of pregnancy; P = 0.041), and lower birth weight (1,737 +/- 542 vs. 1,845 +/- 467 g; P = 0.002) compared to FGR without oligohydramnios., Conclusions: Oligohydramnios is a significant risk factor for adverse perinatal outcome in FGR pregnancies; nevertheless, no significant differences in placental pathologies were noted.

Objective: To compare pathological findings of placentas from term and preterm pregnancies complicated by intrauterine fetal death (IUFD)., Study Design: A retrospective cohort study was conducted including deliveries complicated by IUFD. A comparison was made between placentas from term and preterm (<37 weeks' gestation) pregnancies complicated by IUFD. A second analysis was undertaken comparing IUFD placentas delivered before and after 34 weeks' gestation. Uteroplacental insufficiency was defined when one or more of the following pathological features were found: placental infarct, poor vascularity of the chorionic villi, intravascular thrombi and vascular occlusion., Results: During the study period, 849 placentas of IUFD were examined. Gross and microscopic pathological finding were noted. When comparing gross and microscopic findings in term and preterm (<37 weeks) IUFD placentas, higher rates of calcifications, tissue congestion and cellular metaplasia were found in term vs. preterm placentas. Significantly increased rates of poor tissue vascularity, placental vascular occlusion and uteroplacental insufficiency were demonstrated in preterm IUFD placentas. When comparing pathological findings in IUFD placentas delivered before and after 34 weeks' gestation, higher rates of abnormal cord insertion, calcifications, tissue congestion, infarcts and intravascular thrombi as well as poor tissue vascularity and placental vascular occlusion were demonstrated in IUFD placentas delivered before 34 weeks. Regardless of gestational age at the time of IUFD in more than 90% of placentas vascular wall thickening was found. A third of both term and preterm placentas demonstrated histological chorioamionitis., Conclusions: A vast majority of IUFD placentas reveal numerous pathological findings that reflect uteroplacental insufficiency and abnormal blood supply. Different characteristics were noted in term and preterm placentas of pregnancies complicated by IUFD. Better definition of causes and associated placental pathological findings of IUFD might aid clinicians in counseling such patients regarding the reason and risk of recurrence in subsequent pregnancies.

The aim of the present study was to examine the effect of lipopolysaccharide (LPS) on the levels of prostaglandin E(2) (PGE(2)) in the perfusates of the fetal and the maternal compartments of perfused human term placental tissue. Term placentas were perfused for 10h in the absence [control, (n=4)] and presence of LPS [LPS=1 microg/kg perfused placental tissue, (n=4)] in the maternal reservoir. Perfusate samples from the fetal and the maternal circulations were collected every 30 min and examined for PGE(2) levels by radio-immunoassay. PGE(2) levels in the fetal circulation were gradually increased reaching significant peak value of 479+/-159 pg/ml, as compared to PGE(2) levels in the maternal circulation (140+/-146 pg/ml) (p<0.05). After 10 hours of perfusion with control medium, PGE(2) levels in the maternal circulation (347+/-144 pg/ml) were significantly higher as compared to the fetal circulation (150+/-57 pg/ml) (p<0.05). In presence of LPS, PGE(2) levels in the fetal circulation increased reaching a peak value of 1028+/-663 pg/ml after 240 min of perfusion. The levels of PGE(2) in the control group after 240 min of perfusion were significantly lower (156+/-77 pg/ml) (p<0.05). No significant differences were detected in the levels of PGE(2) in the perfusate of the maternal compartment in presence of LPS, as compared to control. Our results suggest that the placenta may play an important role in maintaining high levels of PGE(2) in the fetal circulation and low PGE(2) levels in the maternal circulation during normal pregnancy. Moreover, placental PGE(2) release into the fetal and the maternal circulations may be differently affected in presence of intra-uterine infection/inflammation.

The aim of the present study was to examine the effect of lipopolysaccharide (LPS) on the secretion of the pro-inflammatory cytokine interleukin-1beta (IL-1beta) and of its natural inhibitor interleukin-1 receptor antagonist (IL-1Ra), by perfused human term and preterm placental tissue. Eight term and eight preterm placentae were collected immediately after delivery; four term and four preterm placentae were perfused with control medium (without LPS) and the other four term and four preterm placentae were perfused with medium containing LPS. The release of IL-1beta into the maternal compartment by term placenta was significantly higher than the release by preterm placenta (p<0.001). However, there were no significant differences between IL-1beta levels released into the fetal compartments of term and preterm placentae. No significant differences were observed in the release of IL-1Ra into the maternal and fetal compartments of term placenta, when compared to preterm placenta. Exposure to LPS significantly decreased the capacity of term placenta to release IL-1beta into the maternal compartment (p<0.001) and increased the capacity of term placenta to release IL-1Ra into the maternal and fetal compartments (p<0.001 and p=0.017, respectively). However, the capacity of preterm placentae to release IL-1beta and IL-Ra into the maternal and fetal compartments was not affected by LPS. IL-1beta was expressed by both term and preterm placentae before and after perfusion (+/- LPS), by epithelial cells of the amnion, chorion, by syncytiotrophoblast and stromal cells of villous tissue and by the decidua. IL-1Ra in term and preterm placentae was expressed before perfusion mainly in epithelial cells of the amnion. After perfusion of term placentae (+/- LPS), additional IL-1Ra expression was seen in epithelial cells of the amnion and in syncytiotrophoblast and stromal cells of villous tissue and by the decidua. However, perfusion of preterm placentae (+/- LPS) did not affect IL-1Ra expression. The localization of IL-1beta and IL-1Ra in both term and preterm human placental tissue suggests a their physiologic role. The data presented indicates that the IL-1 system in term and preterm placentae seems to be differently affected by LPS. Down-regulation in the release of the pro-inflammatory cytokine IL-1beta and the up-regulation of its antagonist (IL-1Ra) may be a part of the inflammatory response to infection in human term, but not preterm, placentae. The IL-1 system in term and preterm placentae seems to be differently affected by LPS.

The aim of the study was to examine the stimulatory effect of the inflammatory agent lipopolysaccharide (LPS) on the capacity of human term placenta to secrete interleukin (IL)-15 and IL-18. Isolated placental cotyledons from normal human term deliveries were dually perfused for ten hours with perfusion medium alone (n=5) or with perfusion medium containing LPS (1 microg/kg perfused placental tissue) (n=5). Placental tissue was collected from three different placental compartments (amnion, chorion, and placenta) before and after perfusion. The placental tissues collected were homogenized and examined for IL-15 and IL-18 by ELISA. In addition, formalin-fixed and paraffin-embedded sections from term placentas before perfusion were stained by immunohistochemistry to characterize the cellular origin of placental IL-15 and IL-18. Statistical significance was determined using paired/unpaired t-test. p<0.05 was considered significant. Our results show that IL-15 and IL-18 are produced more by chorionic tissue, as compared to the amnion and placental tissues. Moreover, we show that IL-15 and IL-18 are expressed by epithelial cells of the amnion, chorionic cells of the chorion and decidual cells of the decidua. However, IL-15, but not IL-18, was expressed also by syncytiotrophoblasts of the villi. Perfusion of LPS did not affect the capacity of amnion, chorion and placental tissues to secrete IL-15 and IL-18, as compared to control. The expression of IL-15 and IL-18 in the different compartments of the human placenta suggests a possible role for these two cytokines in normal placental development, pregnancy and labor. Moreover, our results indicate that IL-15 and IL-18 are not part of the mechanism of the response of human placenta to LPS.

Objective: The study was aimed to determine whether the method of placental removal at the time of the cesarean delivery is associated with postpartum complications such as postpartum fever and wound infection. In addition it was aimed to identify other complications following cesarean delivery., Methods: A prospective observational study was conducted, including 426 women who underwent cesarean deliveries between January 2004 and March 2005, in a tertiary medical center. A multivariable logistic regression model, with backward elimination, was constructed in order to identify independent risk factors associated with the occurrence of wound infection or fever. A sample size of about 150 subjects in each group was needed to demonstrate a difference of 15% between the two methods of placental removal, with a probability of 95% and power of 80%., Results: Manual removal of the placenta occurred in 269 operations while in 157 women the placenta was removed in a spontaneous method. No statistically significant differences were noted between the two methods of removal of the placenta regarding the risk for fever (7.8% in the group of the manual removal, as compared with 5.1% in the group of the spontaneous method; P=0.284) or for wound infection (3.7% in the group of the manual removal compared with 5.1% in the group of the spontaneous method; P=0.495). Using a multivariable logistic regression model, with backward elimination, the following risk factors were identified for postcesarean fever, or wound infection: unskilled surgeon (OR 3.2, 95% CI 1.4-7.8), number of previous cesarean deliveries (OR 1.8, 95% CI 1.3-2.6) and maternal hypertension (OR 3.3, 95% CI 2.0-38.5)., Conclusion: The method of placental removal during cesarean delivery is not associated with the risk for either wound infection or postpartum fever.

This study has compared the functional capacity of term and preterm placentas in terms of production of pro-inflammatory cytokines in a perfusion system reflecting their ability to react to inflammatory agents, such as lipopolysaccharide (LPS), mimicking the situation of chorioamnionitis. We have demonstrated that term placentas secrete higher levels of tumor necrosis factor (TNF)-alpha compared with preterm placentas. Moreover, TNF-alpha secretion was significantly higher after exposure to LPS in the maternal and fetal sides of term placentas. In contrast, in preterm placentas, only the fetal side responded with a significant increase in secretion of TNF-alpha after exposure to LPS. The maternal side of term placentas secreted significantly higher amounts of interleukin (IL)-6 compared with preterm placentas. Exposure to LPS significantly decreased IL-6 secretion from the maternal side in both term and preterm placentas. Moreover, the fetal side of term placentas secreted significantly lower amounts of IL-6 compared with preterm placentas. In summary, this study has indicated that term and preterm placental tissues have a differing responsiveness to LPS stimulation, with term placentas disposed to a higher TNF-alpha:IL-6 ratio. Release of cytokines into fetal circulation is less than into the maternal side. However, TNF-alpha is released into fetal circulation after LPS stimulation and this may be relevant to the etiology of chorioamnionitis.

Three different protocols were carried out to evaluate the effect of magnesium sulfate (MgSO4) on the capacity of the normal human placenta to secrete TNF-alpha and IL-6 in presence and absence of angiotensin II (AII). Ten placentas were perfused with MgSO4 (6-7 mg%) or medium in the absence or presence of AII. Perfusate samples from fetal and maternal sites were collected and examined for IL-6 and TNF-alpha by ELISA. The maternal site of placentas exposed to AII showed only basal levels of TNF-alpha. Exposure of the placentas to MgSO4 resulted in significant increase in TNF-alpha and IL-6 in the maternal site (p < 0.05). However, the effect of MgSO4 was significantly attenuated by AII injected in presence of MgSO4. TNF-alpha and IL-6 levels in the maternal site significantly decreased (p < 0.05). The fetal site of the placentas exposed to MgSO4 or AII separately showed only basal levels of TNF-alpha and IL-6. However, TNF-alpha and IL-6 levels were significantly higher after injection of AII in the presence of MgSO4 compared to TNF-alpha levels in the fetal site of placentas exposed to AII alone (p < 0.05) or MgSO4 alone (p < 0.01). MgSO4 induced the ability of the placental maternal site to secrete TNF-alpha and IL-6. In the presence of both MgSO4 and AII, the effect of MgSO4 on the maternal site was significantly reduced. However, in the fetal site, MgSO4 alone had no significant effect on TNF-alpha and IL-6 levels although, in presence of AII and MgSO4, there was a significant increase in TNF-alpha and IL-6 levels. Elevation of TNF-alpha and IL-6 in the fetal compartment, which may affect fetal brain growth and development and placental function should be considered before administration of MgSO4 during pregnancy.

Objective: To investigate the transfer of therapeutically important fluoroquinolones: ciprofloxacin, ofloxacin and levofloxacin, through the isolated perfused human placenta, from the maternal to the fetal compartment., Study Design: Isolated placental cotyledons from normal human term placentae were dually perfused with M199 medium enriched with 3g/l bovine serum albumin and 1g/l glucose. Perfusion rates were 12 and 6 ml/min in the maternal and fetal circulation, respectively. Maternal and fetal closed circulation was used to evaluate steady-state concentrations and transplacental gradient formation. Eighteen placentae were used in our study: six for each experiment with ciprofloxacin, ofloxacin and levofloxacin were added to the maternal circulation. Samples were collected from the maternal and fetal compartments. Antipyrine was used as a reference drug that crosses the placenta by simple diffusion. The concentrations of ciprofloxacin, ofloxacin, levofloxacin and antipyrine were measured by specific HPLC (high performance liquid chromatography) methods. Results are presented as mean+/-S.D., Results: In all the placentae, ciprofloxacin, ofloxacin, levofloxacin crossed the placenta from the maternal to the fetal compartment. The mean transplacental transfer percent of ciprofloxacin was 3.2+/-0.7% and the transplacental transfer index, the ratio of transplacental transfer between ciprofloxacin and antipyrine was 0.34+/-0.12. The mean transplacental transfer percent of ofloxacin was 3.7+/-2.4% and the transplacental transfer index was 0.33+/-0.3. The mean transplacental transfer percent of levofloxacin was 3.9+/-1.5% and the transplacental transfer index was 0.34+/-0.2., Conclusions: Only a small fraction of ciprofloxacin, ofloxacin and levofloxacin passed from the maternal to the fetal compartment. This fraction is significantly smaller compared to antipyrine. This may indicate that there is a barrier to the transport of fluoroquinolones in human placenta.

Problems: To determine if magnesium sulfate (MgSO4) attenuates the vasoconstrictor effect of angiotensin II (Ag II), endothelin-1 (ET-1) and thromboxane mimetic (TX) in the human fetal placental vasculature and if interleukin-1 beta (IL-1beta) is involved in this process., Study Design: Isolated placental cotyledons (n = 18) were dually perfused with fetal perfusion pressure used as an index of vascular response. The vasoconstriction effect of bolus injection of various concentrations of Ag II (10(-1)) 10(-6) M) or ET-1 (10-(10)-10(-4) M) or TX (10(-10)) 10(-5) M) was established in the absence or presence of MgSO4 (7 mg% constant infusion during 10 hr). Statistical significance was determined by paired t-test and ANOVA., Results: MgSO4 significantly attenuates the vasoconstrictor effect of Ag II in the fetal placental vasculature in the human placenta (P = 0.02). Moreover, significant attenuation of vasoconstrictor response to ET-1(10(-10))10(-5) M) was observed in the presence of MgSO4 (P = 0.02). However, no attenuation of the vasoconstrictor response to TX was noted in the presence of MgSO4 (P > 0.5). Ag II and TX were shown to induce IL-1beta secretion by placental tissue. This effect was completely reduced by perfusion of MgSO4 (7 mg%; constant infusion)., Conclusions: MgSO4 significantly attenuates the vasoconstrictor effect of Ag II and ET-1 in the fetal-placental vasculature in the human placenta, but not that of TX. Inhibition of local production of IL-1beta could be one of the mechanisms used by MgSO4 to reduce the vasoconstrictory effect of Ag II and TX in human placental cotyledone.

The aim of the study was to investigate the stimulatory effect of lipopolysaccharide (LPS) on IL-lalpha production in different compartments of term and preterm placental tissues. Homogenates from amnion, chorion, and from fetal (subchorionic placental tissues, maternal decidua, and mid-placental tissue before and after perfusion of isolated placental cotyledons of 5 term placentas and 4 placentas obtained after preterm birth (28-34 W of gestation) were examined. Isolated placental cotyledons were dually perfused LPS (100 ng/kg perfused placental tissue) was perfused into the maternal side during 10 hours. Homogenates of the samples were examined by ELISA for IL-1alpha levels, and paraffin sections of the samples were stained by immunohistochemical staining, to characterize the cellular origin of placental IL-1alpha. Paired t test and ANOVA determined statistical significance. In the homogenates, there was a tendency towards higher IL-lalpha levels in all preterm placental compartments as compared to the term compartments before perfusion. A significant increase was observed only in the chorion compartment (p = 0.035). LPS had significantly increased IL-la levels only in the decidua compartment of term placentas as compared to other placental compartments (p = 0.0004), and had decreased IL-1alpha levels in the mid-placenta (p = 0.034). In preterm placentas, addition of LPS did not affect the expression levels of IL-1alpha in either fetal or maternal compartments as determined by ELISA and immunohistochemical staining. IL-la levels in the chorion compartment of preterm placenta were significantly higher as compared to term placenta. LPS affects placental tissues of term and preterm placentas differently. Also, in the term placentas, LPS affected the different compartments differently. Thus, IL-1alpha may have a key role (as a autocrine/paracrine factor) in the regulation of normal and pathological pregnancy and parturition.

The human placenta is the interface between the mother and fetus in the uterus. Until recently it was generally believed that the uterus provides a protective environment for the fetus. It is now accepted that any chemical substance, including any therapeutic agent, administered to a mother is able to permeate across the placental barrier. Unfortunately, the placental transfer of substances and their distribution in the placenta is not well established. Understanding the structure of placental transporters and their function may serve as the ideal tool for drug development and the cure of mother and fetus during pregnancy.

Objective: To determine the effect of quinidine and verapamil, known antiarrhythmic agents and P-glycoprotein (Pgp) inhibitors, on digoxin transport from the maternal to the fetal compartment in the isolated perfused human placenta., Study Design: Isolated placental cotyledons from normal human placentae (n=20) were dually perfused with M199 medium enriched with albumin (0.3%) and glucose (0.1%). The maternal and the fetal circulation flow rates were 12 and 6 ml/min, respectively. Closed circulations were used to evaluate steady state transplacental gradient formation. In six placentae quinindine was added to the maternal circuit; after 45 min of perfusion, digoxin was added to the maternal circulation. The effect of verapamil on digoxin transfer from the maternal to the fetal compartments was explored in five placentae. In six additional placentae the transfer of digoxin was studied in the absence of quinidine. Transplacental passage of digoxin was calculated from repeated fetal and maternal perfusate samples. Digoxin levels were determined in perfusate samples by fluorescence polarization immunoassay. Antipyrine was added to the maternal reservoir of all placentae as reference substance., Results: The transfer of digoxin (alone) and in the presence of quinidine or verapamil was 10.93+/-3.71, 9.00+/-5.2 and 12.94+/-4.86%, respectively. The levels of digoxin in the fetal compartment, 0.62+/-0.20, 0.48+/-0.29 and 0.60+/-0.26 ng/ml, respectively, were not significantly affected by quinidine and verapamil. These Pgp modulators, also did not influence significantly the steady state levels of digoxin in the maternal compartment., Conclusion: Neither quinidine nor verapamil affected the transplacental transfer of digoxin in vitro in normal human placentae. In contrast to the other tissues, they do not inhibit Pgp activity in term human placentae.

Objective: The aim of our study is to determine whether oxytocin acts differently on the fetal-placental vascular bed of normal and meconium impregnated placentas., Study Design: Isolated placental cotyledons (n=10) were dually perfused with fetal perfusion pressure used as an index of vascular resistance. As perfusion medium we used lactated Ringer salt solution, containing polyvinylpyrolidone (25 g/l), bovine serum albumin (0.1 mg/ml), glucose (1.0 g/l), heparin (20 IU/ml) and gentamycin (48 microg/ml). The pH of the medium was adjusted to 7.4 with bicarbonate. The maternal site was gassed with 95% O(2):5% CO(2) and in the fetal site with 95% N(2):5% CO(2) at 37 degree C. Perfusion rates were 4-6 and 10-12 ml/min in the fetal and maternal circulation, respectively. TNF-alpha and IL-beta1 levels in the fetal-placental perfusate were evaluated using specific commercial ELISA kits., Results: No significant changes in the amount of TNF-alpha release were observed after injection of oxytocin into the fetal circulation (31+3pg/ml; P=0.5). No IL-beta1 activity was observed in the fetal perfusate of normal and meconium impregnated placentas during the experiments. No significant difference was seen in basal perfusion pressure in normal and meconium impregnated placentas, however, a bolus injection of oxytocin (10U/ml) resulted in a significant increase in perfusion pressure in meconium impregnated placentas from basal pressure of s45+5 to 88+4 mm Hg after injection of oxytocin, (P=0.004, ANOVA)., Conclusion: Vasoconstrictive effect of oxytocin was observed only in meconium impregnated placentas and no vascular effect of oxytocin was documented in normal placentas. The clinical implication of our findings is that one should use oxytocin for stimulation of labor with caution in the presence of meconium stained amniotic fluid.

Objective: To determine the effects of albumin (BSA) concentration in perfusion medium on digoxin transfer in isolated perfused human placental cotyledon., Study Design: Isolated placental cotyledons from 13 normal human placentas were dually perfused after cannulating artery and vein of the chorionic plate and piercing 4 catheters through the corresponding basal plate with M199 medium enriched with BSA and glucose. Flow rates were 12 and 6 ml/min in the maternal and fetal circuits, respectively. Digoxin was added to the maternal reservoir at a final concentration of 5.51 +/- 1.00 ng/ml. BSA in maternal and fetal perfusate was kept at 3 concentrations: 1, 3 and 5 mg/ml (Groups I, II, III). Transplacental passage of digoxin was calculated from repeated fetal and maternal perfusate samples collected over 3 hours in the 3 groups. Digoxin levels were measured by FPIA (TDx, Abbott)., Results: There was no transfer of digoxin from the maternal to fetal compartment when the concentration of BSA was 1 mg/ml. Increasing the concentration of BSA led to a substantial increase in the transfer of digoxin to the fetal compartment. Steady state levels of digoxin in the fetal compartment were 0.61 +/- 0.19 ng/ml at 3 mg/ml of BSA., Conclusion: Maternal and fetal serum concentration of BSA affect digoxin transfer in isolated perfused human placentas. Three mg/ml are considered to be the optimal albumin concentration.

Objective: To study the effect of indomethacin on the vasculature of isolated perfused human placental cotyledon in normal and meconium pretreated placentae., Study Design: Isolated placental cotyledons were dually perfused and fetal perfusion pressure was used as an index of vascular resistance. Meconium-stained amniotic fluid (MSAF) was collected from patients after artificial rupture of membranes, diluted 1:2, 1:4, 1:16 and 1:32 and a spectrophotometric determination of meconium concentration in amniotic fluid was performed. Only MSAF with an optical density of 20.0 units per gram was used in this study. In five placentae, the effect of indomethacin (100 microg/ml continuous perfusion from the fetal site) on basal pressure of the fetal-placental vasculature was established. In five more placentae, the effect of indomethacin on MSAF-induced vasoconstriction was established when a bolus injections of 1 ml MSAF was made into the fetal circulation. The statistical significance of response to MSAF injection was determined by paired t-test and ANOVA repeated measurements., Results: A significant vasoconstrictor response to MSAF was achieved in normal placentae. Bolus injections of MSAF into the fetal circulation resulted in a significant increase in perfusion pressure (P=0.0026). Indomethacin was capable of significantly reducing the basal perfusion pressure (P=0.03). Significant attenuation of vasoconstrictor response to MSAF occurred in the presence of indomethacin (P=0.0016)., Conclusion: Indomethacin causes a significant reduction in basal pressure of fetal placental vasculature in the human placental circulation in vitro and is capable of attenuating the vasoconstrictory activity of MSAF. The mechanism of such activity may be explained partially by the inhibitory effect of indomethacin on the PG-mediated pathways.

Objective: To evaluate the effect of pathological placental conditions such as intrauterine growth restriction (IUGR) or exposure to angiotensin II (AII) on TNF-alpha secretion in the vasculature of isolated human placental cotyledons., Study Design: Isolated placental cotyledons from 10 normal and four intrauterine growth restricted fetuses were dually perfused. Perfusate samples from the fetal circulation were collected every 30 min during 120 min. TNF-alpha levels in the fetal-placental perfusate were evaluated using specific commercial ELISA kits. In three additional normal placentae, bolus injections of angiotensin II (10(-9)-10(-4) mol/l) were given into the fetal-placental circulation and perfusate samples were collected. Statistical significance of difference TNF-alpha levels between different conditions was determined by analysis of variance (ANOVA) and paired t-test., Results: TNF-alpha levels were significantly higher in the perfusate of IUGR placentae as compared with normal placentae after 120 min of perfusion (mean 410+/-121 vs. 39+/-14 pg/ml, P=0.005). There was a significant dose-dependent increase in TNF-alpha levels in the placental perfusate after a bolus injection of AII 66 pg/ml with AII 10(-9) mol/l vs. 97 pg/ml with AII 10(-5) mol/l (P=0.004), respectively., Conclusions: Placental pathology related to condition IUGR might induce the secretion of proinflammatory cytokines such as TNF-alpha, which may enhance the vasoconstriction of the fetal placental vascular bed.

Objective: The purpose of this study was to study was to determine the effect of meconium stained amniotic fluid on the vasculature of isolated perfused human placental cotyledon., Study Design: Isolated placental cotyledons were dually perfused. Fetal perfusion pressure was used as an index of vascular resistance. Meconium stained amniotic fluid (MSAF) was collected from patients after artificial rupture of membranes in term gestation. A dilution of meconium (1:2; 1:4; 1:8; 1:16) was performed. Optical density (OD) of MSAF varied between 0 and 35.0 units/g as determined by spectrophotometry. Bolus injections of 1.0 ml of MSAF at different concentrations were injected into the fetal circulation. Heated and dialyzed MSAF after adequate dilution and evaluation of optical density were injected into fetal circulation in separate experiments., Results: Analysis of variance (ANOVA) and paired t-test were used for statistical analysis. Bolus injections of MSAF into the fetal circulation resulted in a concentration-dependent increase in perfusion pressure. MSAF with the highest OD resulted in a greater change in perfusion pressure as compared to more dilute MSAF (P=0.0001). After high OD amniotic fluid injections the provoked contractions lasted longer compared to dilute MSAF (P=0.006). MSAF after dialyzation did not exhibit any vasoconstrictive effect., Conclusion: Meconium is a vasoconstrictive agent in the fetal-placental vasculature and has a concentration dependent effect.

Objective: Our purpose was to study the interaction of nitric oxide and superoxide anion on the vasculature of the isolated perfused human placental cotyledon., Study Design: Isolated placental cotyledons were preconstricted with the thromboxane mimetic U46619, and fetal perfusion pressure was used as an index of response. The interaction of nitric oxide and O2- was studied by three protocols: (1) with endogenous nitric oxide, (2) with addition of exogenous nitric oxide, and (3) with inhibition of nitric oxide synthesis by the nitric oxide synthase inhibitor N-nitro-L-arginine. O2- was generated by infusion of purine-xanthine oxidase. Statistical significance of response to treatment was determined by paired t test., Results: Infusion of xanthine oxidase with purine in the presence of endogenous nitric oxide resulted in vasodilation (p < 0.05). Vasodilation was more pronounced in the presence of exogenous nitric oxide (p < 0.008). Coinfusion of xanthine oxidase with purine in the presence of N-nitro-L-arginine to inhibit nitric oxide synthesis resulted in vasoconstriction., Conclusion: We conclude that, rather than superoxide inactivating nitric oxide, interaction of the two radicals generates in the placental vasculature a vasodilator, which may be peroxynitrite.

Objective: To evaluate the effects of angiotensin II and brain natriuretic peptide on the placental vasculature of diabetic women., Methods: Term placentas from five diabetic women and five nondiabetic controls were collected. Isolated placental cotyledons were perfused dually with fetal perfusion pressure as an index of vascular response. The effect of angiotensin II (10(-10)-10(-5) mol/L bolus injection) was established in the fetal-placental vasculature of all placentas in the absence or presence of brain natriuretic peptide (10(-8) mol/L final concentration). Data were analyzed using repeated measures analysis of variance and paired t test where appropriate., Results: A significant vasoconstrictor response to angiotensin II was achieved in placentas of both diabetic and nondiabetic women (P < .001); however, the angiotensin II-induced increase in perfusion pressure was significantly greater in the diabetic group (P < .01). Significant attenuation of vasoconstrictor response to angiotensin occurred in the presence of brain natriuretic peptide in placentas of both nondiabetic (P < .0025) and diabetic (P < .025) women, but the effect was more prominent in the diabetic group., Conclusion: The in vitro placental vasculature of diabetic women is more sensitive to angiotensin II than is the in vitro placental vasculature of nondiabetic women. The attenuation exerted by brain natriuretic peptide on angiotensin II-induced vasoconstriction is more prominent in placentas from diabetic women compared to those from nondiabetic women.

Objective: To determine whether atrial natriuretic peptide (ANP) attenuates the vasoconstrictor effects of angiotensin II (AII), a thromboxane mimetic (U46619), and endothelin-1 in the human fetal-placental vasculature and to determine whether nitric oxide (NO) has a role in the vasodilator activity of ANP., Methods: Isolated placental cotyledons were dually perfused, with fetal perfusion pressure used as an index of vascular response. The effects of AII (10(-10)-10(-6) mol/L bolus injection), endothelin-1 (10(-7) mol/L bolus), and U46619 (10(-9)-10(-6) mol/L bolus or 10(-8) mol/L infusion) were established in the absence or presence of ANP (10(-8) mol/L). The role of NO as a mediator of ANP action was investigated by perfusion with n-nitro-L-arginine (NNLA, 10(-3) mol/L), an inhibitor of NO synthase. Statistical significance was determined by analysis of variance., Results: Atrial natriuretic peptide caused significant attenuation of vasoconstrictor responses to AII, but weak attenuation of endothelin-1 and no attenuation of U46619. Use of NNLA did not affect the attenuation of AII-induced vasoconstriction by ANP., Conclusions: Atrial natriuretic peptide is a vasodilator of the fetal-placental vasculature constricted with AII and endothelin-1, but not with U46619. Nitric oxide does not mediate the action of ANP.

Objective: Our purpose was to compare the actions of atrial natriuretic peptide and brain natriuretic peptide in the human placental vasculature., Study Design: Isolated placental cotyledons were dually perfused with fetal perfusion pressure used as an index of vascular response. The effect of angiotensin II (10(-10) to 10(-6) mol/L bolus injection) was established in the absence or presence of atrial natriuretic peptide (10(-8) mol/L) or brain natriuretic peptide (10(-8) mol/L final concentration). The role of nitric oxide as a mediator of natriuretic peptide action was investigated by perfusion of n-nitro-L-arginine (10(-3) mol/L), an inhibitor of nitric oxide synthase. Attenuation of the action of atrial natriuretic peptide by placental peptidases was studied by perfusion with the peptidase inhibitor benzamidine (2 x 10(-2) mol/L). Statistical significance was determined by analysis of variance and paired t test., Results: Significant attenuation of vasoconstrictor responses to angiotensin II occurred within both atrial natriuretic peptide and brain natriuretic peptide; however, brain natriuretic peptide was more effective. n-Nitro-L-arginine did not affect the attenuation of angiotensin II-induced vasoconstriction by atrial or brain natriuretic peptides. In the presence of benzamidine atrial natriuretic peptide exerted a significantly greater vasodilator effect., Conclusion: Brain natriuretic peptide is a more potent vasodilator of the placental vasculature than is atrial natriuretic peptide. The low efficacy of atrial natriuretic peptide may be related to placental peptidases. Nitric oxide does not mediate the action of atrial natriuretic peptide or brain natriuretic peptide.

Hana Polachek,1,* Nir Debotton,2,* Valeria Feinshtein,1 Mazal Rubin,1 Zvi Ben-Zvi,1,‡ Gershon Holcberg,3 Riad Agbaria,1 Arik Dahan1 1Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel; 2Department of Chemical Engineering, Shenkar College of Engineering and Design, Ramat-Gan, Israel; 3Division of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel *These authors contributed equally to this work ‡Professor Zvi Ben-Zvi passed away on August 4, 2017 Introduction: Six years after the US Food and Drug Administration approval of the broad-spectrum antibiotic ofloxacin (OFLX), the chiral switching of this racemic mixture resulted in a drug composed of the l-optical isomer levofloxacin (LVFX). Since both fluoroquinolones (FQs) were introduced to the pharmaceutical market, they have been widely prescribed by physicians, with careful administration during pregnancy and breastfeeding. Therefore, the role of the influx and efflux placental transporters in the concentrations of these drugs that permeate through human placental barrier model was investigated in this study. Methods: The contribution of major carriers on the transplacental flux of OFLX and LVFX uptake into choriocarcinoma BeWo cells was evaluated in the presence vs absence of well-known inhibitors. Results: Our results reveal that neither the influx transporters such as organic cation transporters, organic anion transporters, and monocarboxylate transporters nor the efflux transporters such as P-glycoprotein or breast cancer resistance protein significantly affected the transport of OFLX. In contrast, multiple transporters revealed pronounced involvement in the transfer of the levorotatory enantiomer in and out of the in vitro placental barrier. These data suggest a non-carrier-mediated mechanism of transport of the racemic mixture, while LVFX is subjected to major influx and efflux passage through the placental brush border membranes. Conclusion: This study provides underlying insights to elucidate the governing factors that influence the flux of these FQs through organ barriers, in view of the controversial safety profile of these drugs in pregnant population. Keywords: drug transport, fluoroquinolones, levofloxacin, ofloxacin, placenta, pregnancy