Perfusion Of Placenta Research Articles

Current opinion: antiretrovirals during pregnancy and breastfeeding.

To review the most important literature from the past 2 years on the pharmacokinetics of antiretrovirals in pregnancy, placental transfer, and breastmilk. Concentrations of antiretrovirals frequently used in pregnancy and their placental transfer are described, together with infant exposure through breastmilk. Also, applications of ex-vivo and in-silico studies, such as placenta perfusion studies and PBPK models, are discussed. Great efforts were made in the past 2 years to accelerate the availability of data on antiretrovirals during pregnancy and lactation. Bictegravir showed decreased but still sufficient concentrations during pregnancy, leading to a label change by the FDA. In-silico and clinical studies on long-acting cabotegravir and rilpivirine generated information leading to cautious use of these formulations in pregnancy. Low infant exposure to antiretrovirals through breastmilk is expected for most compounds. Despite the impact of these studies, more incentives are needed for earlier implementation, for instance, during the developmental phase of drugs, to provide women antenatally with proper information on their drugs.

P05-02 Optimization of the betamethasone and dexamethasone dosing regimen during pregnancy: a combined placenta perfusion and pregnancy physiologically-based pharmacokinetic modeling approach

P05-02 Optimization of the betamethasone and dexamethasone dosing regimen during pregnancy: a combined placenta perfusion and pregnancy physiologically-based pharmacokinetic modeling approach

Optimization of the betamethasone and dexamethasone dosing regimen during pregnancy: a combined placenta perfusion and pregnancy physiologically based pharmacokinetic modeling approach

BackgroundAntenatal betamethasone and dexamethasone are prescribed to women who are at high risk of premature birth to prevent neonatal respiratory distress syndrome. The current treatment regimens, effective to prevent neonatal RDS, may be suboptimal. Recently, concerns have been raised regarding possible adverse long-term neurological outcomes due to high fetal drug exposures. Data from non-human primates and sheep suggest maintaining a fetal plasma concentration above 1 ng/mL for 48 hours to retain efficacy, while avoiding undesirable high fetal plasma levels. ObjectiveWe aimed to re-evaluate the current betamethasone and dexamethasone dosing strategies to assess estimated fetal exposure and provide new dosing proposals that meet the efficacy target but avoid excessive peak exposures. Study designA pregnancy physiologically-based pharmacokinetic model was used to predict fetal drug exposures. To allow prediction of the extent of betamethasone and dexamethasone exposure in the fetus, placenta perfusion experiments were conducted to determine placental transfer. Placental transfer rates were integrated in the PBPK model to predict fetal exposure and model performance was verified using published maternal and fetal PK data. The verified pregnancy physiologically-based pharmacokinetic models were then used to simulate alternative dosing regimens to establish a model-informed dose. ResultsEx vivo data showed that both drugs extensively cross the placenta. For betamethasone 15.7 ± 1.7% and for dexamethasone 14.4 ± 1.5% of the initial maternal perfusate concentration reached the fetal circulations at the end of the 3-hour perfusion period. Pregnancy physiologically-based pharmacokinetic models that include these ex vivo-derived placental transfer rates, accurately predicted maternal and fetal exposures resulting from current dosing regimens. The dose simulations suggest that for betamethasone intramuscular a dose reduction from 2 dosages 11.4 mg, 24 hours apart, to 4 dosages 1.425 mg, 12 hours apart would avoid excessive peak exposures and still meet the fetal response threshold. For dexamethasone, the dose may be reduced from four times 6 mg every 12 hours to 8 times 1.5 mg every 6 hours. ConclusionA combined placenta perfusion and pregnancy physiologically-based pharmacokinetic modeling approach adequately predicted both maternal and fetal drug exposures of two antenatal corticosteroids. Strikingly, our PBPK simulations suggest that drug doses might be reduced drastically to still meet earlier proposed efficacy targets and minimize peak exposures. We propose the provided model-informed dosing regimens are used to support further discussion on an updated antenatal corticosteroid scheme and design of clinical trials to confirm the effectiveness and safety of lower doses.

Evaluation of Various Approaches to Estimate Transplacental Clearance of Vancomycin for Predicting Fetal Concentrations using a Maternal-Fetal Physiologically Based Pharmacokinetic Model.

Evaluating drug transplacental clearance is vital for forecasting fetal drug exposure. Ex vivo human placenta perfusion experiments are the most suitable approach for this assessment. Various in silico methods are also proposed. This study aims to compare these prediction methods for drug transplacental clearance, focusing on the large molecular weight drug vancomycin (1449.3g/mol), using maternal-fetal physiologically based pharmacokinetic (m-f PBPK) modeling. Ex vivo human placenta perfusion experiments, in silico approaches using intestinal permeability as a substitute (quantitative structure property relationship (QSPR) model and Caco-2 permeability in vitro-in vivo correlation model) and midazolam calibration model with Caco-2 scaling were assessed for determining the transplacental clearance (CLPD) of vancomycin. The m-f PBPK model was developed stepwise using Simcyp, incorporating the determined CLPD values as a crucial input parameter for transplacental kinetics. The developed PBPK model of vancomycin for non-pregnant adults demonstrated excellent predictive performance. By incorporating the CLPD parameterization derived from ex vivo human placenta perfusion experiments, the extrapolated m-f PBPK model consistently predicted maternal and fetal concentrations of vancomycin across diverse doses and distinct gestational ages. However, when the CLPD parameter was derived from alternative prediction methods, none of the extrapolated maternal-fetal PBPK models produced fetal predictions in line with the observed data. Our study showcased that combination of ex vivo human placenta perfusion experiments and m-f PBPK model has the capability to predict fetal exposure for the large molecular weight drug vancomycin, whereas other in silico approaches failed to achieve the same level of accuracy.

In silico modeling for ex vivo placenta perfusion of nicotine.

Nicotine readily crosses the placenta to reach fetuses. However, membrane transporters, e.g., organic cation transporters (OCTs) play a role in the clearance of nicotine from the fetal to the maternal side, and this is rarely investigated clinically. In this work, we use an in silico model to simulate an ex vivo placenta perfusion experiment, which is the gold standard for measuring the transplacental permeability of compounds, including nicotine. The model consists of a system of seven ordinary differential equations (ODEs), where each equation represents the nicotine concentration in compartments that emulate the ex vivo experiment setup. The transport role of OCTs is simulated bi-directionally at the placenta's basal membrane (the fetal side). We show that the model can not only reproduce the actual ex vivo experiment results, but also predict the likely maternal and fetal nicotine concentrations when the OCT transporters are inhibited, which leads to a ∼12% increase in fetal nicotine concentration after 2hours of OCT modulated nicotine perfusion. In conclusion, a first in silico model is proposed in this paper that can be used to simulate some subtle features of trans-placental properties of nicotine.

Velocity-selective arterial spin labeling perfusion measurements in 2nd trimester human placenta with varying BMI

IntroductionProper placental development is crucial to fetal health but is challenging to functionally assess non-invasively and is thus poorly characterized in populations. Body mass index (BMI) has been linked with adverse outcomes, but the causative mechanism is uncertain. Velocity-selective arterial spin labeling (VS-ASL) MRI provides a method to non-invasively measure placental perfusion with robustness to confounding transit time delays. In this study, we report on the measurement of perfusion in the human placenta in early pregnancy using velocity-selective arterial spin labeling (VS-ASL) MRI, comparing non-obese and obese participants. MethodsParticipants (N = 97) undergoing routine prenatal care were recruited and imaged with structural and VS-ASL perfusion MRI at 15 and 21 weeks gestation. Resulting perfusion images were analyzed with respect to obesity based on BMI, gestational age, and the presence of adverse outcomes. ResultsAt 15 weeks gestation BMI was not associated with placental perfusion or perfusion heterogeneity. However, at 21 weeks gestation BMI was associated with higher placental perfusion (p < 0.01) and a decrease in perfusion heterogeneity (p < 0.05). In alignment with past studies, perfusion values were also higher at 21 weeks compared to 15 weeks gestation. In a small cohort of participants with adverse outcomes, at 21 weeks lower perfusion was observed compared to participants with uncomplicated pregnancies. DiscussionThese results suggest low placental perfusion in the early second trimester may not be the culpable factor driving associations of obesity with adverse outcomes.

PREGNANT WOMEN STRUGGLING WITH HIGH BLOOD PRESSURE AND STRESS IN PREGNANCY AND ROLE OF NITRIC OXIDE SUPPLEMENTS L-ARGININE FOR PROLONG PERIOD

INTRODUCTION: Mental stress can contribute to the exacerbation of hypertension in pregnant women and preeclampsia by the release of stress hormones such as adrenaline and cortisol level. Less nitric oxide (NO)-dependent vasodilation and excess formation of reactive oxygen species could explain poor placenta perfusion already in PIH and Preeclampsia due to impaired endothelial function. Studies have indicated that Nitric oxide supplement L-arginine can lead to beneficial effects on various cardiometabolic markers, including blood pressure and vascular function especially in pregnant mothers. OBJECTIVE: The primary objective of this meta-analysis study of placebo-controlled trials was to assess and ascertain the evidence of effectiveness of L-arginine and its use in enhancing nitric oxide synthesis to translate into tangible improvement in Hypertension and preeclampsia management, Nitric oxide supplement L-arginine’s ubiquitous molecule’s role is a subject of debate and research with focus on both systolic and diastolic values, pregnancy outcomes and understanding of its role in Hypertension resistant to currently available therapies. METHODS: In this study focused on role of L-arginine on high blood pressure during pregnancy, we did a thorough research, effective communication of information from relevant and up-to-date research articles, studies from reputable sources and great places of academic database like PubMed, Google Scholar, medical journals. Around 16 trials were searched in Pub-Med and Google scholar. A total of six trials were included in this meta-analysis. RESULTS: Result of this meta-analysis shows Nitric Oxide L-arginine supplementation showed a mean decrease in diastolic blood pressure and can lead to beneficial effect on blood pressure and vascular function especially in pregnant mothers with stress, mean increase up to 1. 23 weeks (p = 0. 002) for gestation period to delivery but did not showed reduction in systolic blood pressure as compared to placebo. CONCLUSION: This meta-analysis study supports the notion that availability of this substrate for NO synthesis prolongs the latency to development of preeclampsia and decrease the hypertension in a high-risk pregnant woman with Hypertension and stress.

Diffusion-derived vessel density (DDVD) computed from a simple diffusion MRI protocol as a biomarker of placental blood circulation in patients with placenta accreta spectrum disorders: A proof-of-concept study

ObjectivesIncreasing trend of PAS (placenta accreta spectrum disorders) incidence is a major health concern as PAS is associated with high maternal morbidity and mortality during cesarean section. Prenatal identification of PAS is crucial for delivery planning and patients management. This study aims to explore whether diffusion-derived vessel density (DDVD) computed from a simple diffusion MRI protocol differs in PAS from normal placenta. MethodsWe enrolled 86 patients with PAS disorders and 40 pregnant women without PAS disorders. Each patient underwent intravoxel incoherent motion (IVIM) MRI sequence with 11 b-values. Placenta diffusion-derived vessel density (DDVD-b0b50) was the signal difference between b = 0 and b = 50 s/mm2 images. DDVD(b0b50) A/N was calculated as [accreta lesion DDVD(b0b50)]/ [normal placenta DDVD(b0b50)]. The correlation between DDVD and gestational age was explored using Spearman rank correlation. Differences of DDVD(b0b50) A/N in patients with normal placentas and with PAS, and in patients with different subtypes of PAS were explored. ResultsDDVD was negatively correlated with gestational age (p = 0.023, r = −0.359) in patients with normal placentas. DDVD(b0b50) A/N was significantly higher in patients with PAS (median:1.16, mean: 1.261) than normal placenta (median:1.02, mean: 1.032, p < 0.001) and especially higher in patients with placenta increta (median:1.14, mean: 1.278) and percreta (median: 1.20, mean: 1.396, p < 0.001). ConclusionAs a higher DDVD indicates higher physiological volume of micro-vessels in PAS, this study suggests DDVD can be a potential biomarker to evaluate the placenta perfusion.

Variability in perfusion conditions and set-up parameters used in ex vivo human placenta models: A literature review

The ex vivo human placenta perfusion model has proven to be clinically relevant to study transfer- and fetal exposure of various drugs. Although the method has existed for a long period, the setup of the perfusion model has not been generalized yet. This review aims to summarize the setups of ex vivo placental perfusion models used to examine drug transfer across the placenta to identify generalized properties and differences across setups. A literature search was carried out in PubMed September 26, 2022. Studies were labeled as relevant when information was reported, between 2000 and 2022, on the setups of ex vivo placental perfusion models used to study drug transfer across the placenta. The placenta perfusion process, and the data extraction, was divided into phases of preparation, control, drug, and experimental reflecting the chronological timeline of the different phases during the entire placental perfusion process. 135 studies describing an ex vivo human placental perfusion experiment were included. Among included studies, the majority (78.5%) analyzed drug perfusion in maternal to fetal direction, 18% evaluated bi-directional drug perfusion, 3% under equilibrium conditions, and one study investigated drug perfusion in fetal to maternal direction. This literature review facilitates the comparison of studies that employ similar placenta perfusion protocols for drug transfer studies and reveals significant disparities in the setup of these ex vivo placental perfusion models. Due to interlaboratory variability, perfusion studies are not readily comparable or interchangeable. Therefore, a stepwise protocol with multiple checkpoints for validating placental perfusion is needed.

Protein Profiling of Placental Extracellular Vesicles in Gestational Diabetes Mellitus.

Throughout pregnancy, some degree of insulin resistance is necessary to divert glucose towards the developing foetus. In gestational diabetes mellitus (GDM), insulin resistance is exacerbated in combination with insulin deficiency, causing new-onset maternal hyperglycaemia. The rapid reversal of insulin resistance following delivery strongly implicates the placenta in GDM pathogenesis. In this case-control study, we investigated the proteomic cargo of human syncytiotrophoblast-derived extracellular vesicles (STBEVs), which facilitate maternal-fetal signalling during pregnancy, in a UK-based cohort comprising patients with a gestational age of 38-40 weeks. Medium/large (m/l) and small (s) STBEVs were isolated from GDM (n = 4) and normal (n = 5) placentae using ex vivo dual-lobe perfusion and subjected to mass spectrometry. Bioinformatics were used to identify differentially carried proteins and mechanistic pathways. In m/lSTBEVs, 56 proteins were differently expressed while in sSTBEVs, no proteins reached statistical difference. Differences were also observed in the proteomic cargo between m/lSTBEVs and sSTBEVs, indicating that the two subtypes of STBEVs may have divergent modes of action and downstream effects. In silico functional enrichment analysis of differentially expressed proteins in m/lSTBEVs from GDM and normal pregnancy found positive regulation of cytoskeleton organisation as the most significantly enriched biological process. This work presents the first comparison of two populations of STBEVs' protein cargos (m/l and sSTBEVs) from GDM and normal pregnancy isolated using placenta perfusion. Further investigation of differentially expressed proteins may contribute to an understanding of GDM pathogenesis and the development of novel diagnostic and therapeutic tools.

Safety assessment of the SGLT2 inhibitors empagliflozin, dapagliflozin and canagliflozin during pregnancy: An ex vivo human placenta perfusion and in vitro study

Although uncontrolled hyperglycaemia during pregnancy can cause complications for both the mother and her offspring, pharmacological treatment options for gestational and type 2 diabetes in pregnancy are still limited. Empagliflozin (EMPA), dapagliflozin (DAPA) and canagliflozin (CANA) are three sodium glucose co-transporter 2 (SGLT2) inhibitors, a newer group of oral antidiabetics that are well established in the treatment of type 2 diabetes mellitus in non-pregnant patients. To date, no data regarding their placental transfer and safety in pregnant women are available. We performed ex vivo human placental perfusions (n = 4, term placentas, creatinine and antipyrine as connectivity controls) to evaluate the transplacental transfer of EMPA, DAPA and CANA across the placental barrier and assessed their influence on the secretion of two placental peptide hormones, leptin and β-human chorionic gonadotropin (β-hCG). We discovered that all three SGLT2 inhibitors cross the placental barrier and attained maximal foetal to maternal concentration ratios of 0.38 ± 0.09 (EMPA), 0.67 ± 0.05 (DAPA) and 0.62 ± 0.05 (CANA) within the tested 360 min. A moderate but statistically significant decrease in placental leptin – but not β-hCG – secretion was observed during perfusions with SGLT2 inhibitors, which was confirmed in experiments performed with human placental BeWo cells. SGLT2 inhibitors are able to cross the human placental barrier and seem to interfere with placental leptin production. These observations should be considered in the ongoing discussion on the optimal treatment for gestational diabetes and type 2 diabetes mellitus in pregnancy.

Placental transfer of tofacitinib in the ex vivo dual-side human placenta perfusion model

Tofacitinib is a small molecule Janus kinase (JAK) inhibitor, introduced to the European market in 2017, for the treatment of rheumatoid arthritis, psoriatic arthritis and ulcerative colitis. In the treatment of women with autoimmune diseases, pregnancy is a relevant issue, as such diseases typically affect women in their reproductive years. Currently, there is limited data on the use of tofacitinib during pregnancy. To estimate the extent of placental transfer in the absence of clinical data, we conducted ex vivo dual-side perfused human placental cotyledon perfusions. Term placentas were perfused for 180 min with tofacitinib (100 nM, added to the maternal circuit) in a closed-closed configuration. At the end of the perfusions, drug concentrations in the maternal and fetal reservoirs were near equilibrium, at 35.6 ± 5.5 and 24.8 ± 4.7 nM, respectively. Transfer of tofacitinib was similar to that observed for the passive diffusion marker antipyrine (100 µg/mL, added to the maternal reservoir). Final antipyrine maternal and fetal concentrations amounted to 36.9 ± 3.0 and 36.7 ± 1.3 µg/mL, respectively. In conclusion, in the ex vivo perfused placenta tofacitinib traverses the placental barrier rapidly and extensively. This suggests that substantial fetal tofacitinib exposure will take place after maternal drug dosing.

Transplacental migration of maternal natural killer and T cells assessed by ex vivo human placenta perfusion

IntroductionThe transplacental passage of cells between a mother and her fetus, known as microchimerism, is a less studied process during pregnancy. The frequency of maternal microchimeric cells in fetal tissues in physiological pregnancies and mechanisms responsible for transplacental cell trafficking are poorly understood. This study aimed to evaluate the placental trafficking of maternal peripheral blood mononuclear cells (PBMC) using human ex vivo placenta perfusion. MethodsTen placentas and maternal PBMC were obtained after healthy pregnancies. Flow cytometry was used to characterize PBMC subtypes. They showed a higher percentage of CD3+ T cells compared to CD56+ NK cells. The isolated PBMC were stained with a fluorescent dye and perfused through the maternal circuit of the placenta in an ex vivo perfusion system. Subsequent immunofluorescence staining for CD3+ T cells and CD56+ NK cells was performed on placental tissue sections, and the number of detectable PBMC in different tissue areas was counted using fluorescence microscopy. ResultsThe applied method allowed discrimination of perfused autologous maternal cells from cells resident in the placenta before perfusion. Further, it allows additional immunohistochemical labelling and distinction of immune cell subsets. Perfused PBMC were detected in all analyzed placentas, mostly in contact to the syncytiotrophoblast. CD3+ T cells were identified more frequently than CD56+ NK cells and some CD3+ T cells were found inside fetoplacental tissues and vasculature. The results indicate that also other PBMCs than T or NK cells adhere to or enter villous tissue, but they have not been specified in this analysis. DiscussionPrevious studies have detected maternal cells in the fetal circulation which we could mimick in our ex vivo placenta perfusion experiments with fluorescence labelled autologous maternal PBMC. The applied experimental settings did not allow comparison of transmigration abilities of PBMC subsets, but slight modifications of the model will permit further studies of cell transfer processes and microchimerism in pregnancy.

A physiologically based toxicokinetic model of P-glycoprotein transporter-mediated placenta perfusion of dexamethasone in the pregnant rat

The present dosage of Dexamethasone (DEX) administered to pregnant women may pose a risk of toxicity to their unborn offspring. We aimed to develop a maternal-fetal physiologically based toxicokinetic (PBTK) model for DEX in pregnant rats, with a specific focus on the role of the P-glycoprotein (P-gp) transporter in placenta perfusion, and finally facilitate the optimization of clinical DEX dosage. We conducted animal experiments to determine DEX concentrations in various rat tissues, and constructed the PBTK model using MATLAB software. Sensitivity analysis was performed to assess input parameters and the model stability, with fold error (FE) values serving as evaluation indices. Our results indicate the successful construction of the PBTK model, with the fitting key parameters such as the absorption rate constant (Ka), intrinsic hepatic clearance (CLh,int) and intrinsic P-gp clearance (CLint,P-gp). The median concentration of DEX in maternal plasma, fetal plasma, fetal lung, and fetal brain were determined, which allowed us to fit the tissue-to-plasma partition coefficients for the fetal lung (Kp,lung,f) and fetal brain (Kp,brain,f). After making adjustments, all calculated FE values were found to be less than 2, demonstrating the acceptability and accuracy of our model's predictions. Our model integrated external literature data and internal animal experimentation to comprehensively evaluate the maternal-fetal PK characteristics of DEX. These findings provide valuable support for the optimization of clinical DEX dosing.

Placenta-Derived Extracellular Vesicles From Preeclamptic Pregnancies Impair Vascular Endothelial Function via Lectin-Like Oxidized LDL Receptor-1.

Preeclampsia is a complex syndrome that includes maternal vascular dysfunction. Syncytiotrophoblast-derived extracellular vesicles from preeclampsia placentas (preeclampsia-STBEVs) were shown to induce endothelial dysfunction, but an endothelial transmembrane mediator is still unexplored. The LOX-1 (lectin-like oxLDL receptor-1) is a transmembrane scavenger receptor that can cause endothelial dysfunction, and its expression is increased in the endothelium of preeclampsia women. In this study, we hypothesized that LOX-1 mediates the effects of preeclampsia-STBEVs on endothelial function. Preeclampsia-STBEVs were collected by perfusion of placentas from women with preeclampsia and in vitro and ex vivo endothelial cell function were assessed. In human umbilical vein endothelial cells, inhibition of LOX-1 with TS20 (LOX-1 blocking antibody) reduced the uptake of preeclampsia-STBEVs (61.3±8.8%). TS20 prevented the activation of ERK (a kinase downstream of LOX-1) and reduced the activation of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells; 21.1±8.0%) and nitrative stress (23.2±10.3%) that was induced by preeclampsia-STBEVs. Vascular function was assessed by wire myography in isolated mesenteric arteries from pregnant rats that were incubated overnight with preeclampsia-STBEVs±TS20. TS20 prevented endothelium-dependent vasodilation impairment induced by preeclampsia-STBEVs. Nitric oxide contribution to the relaxation was reduced by preeclampsia-STBEVs, which was prevented by TS20. Superoxide dismutase or apocynin, an inhibitor of NOX (nicotinamide adenine dinucleotide phosphate oxidase), restored the impaired endothelium-dependent vasodilation in arteries exposed to preeclampsia-STBEVs. Taken together, our findings demonstrate that LOX-1 mediates the endothelial dysfunction induced by preeclampsia-STBEVs. Our study further expands on the mechanisms that may lead to adverse outcomes in preeclampsia and proposes LOX-1 as a potential target for future interventions.

Microfluidic technology and simulation models in studying pharmacokinetics during pregnancy.

Introduction: Preterm birth rates and maternal and neonatal mortality remain concerning global health issues, necessitating improved strategies for testing therapeutic compounds during pregnancy. Current 2D or 3D cell models and animal models often fail to provide data that can effectively translate into clinical trials, leading to pregnant women being excluded from drug development considerations and clinical studies. To address this limitation, we explored the utility of in silico simulation modeling and microfluidic-based organ-on-a-chip platforms to assess potential interventional agents. Methods: We developed a multi-organ feto-maternal interface on-chip (FMi-PLA-OOC) utilizing microfluidic channels to maintain intercellular interactions among seven different cell types (fetal membrane-decidua-placenta). This platform enabled the investigation of drug pharmacokinetics in vitro. Pravastatin, a model drug known for its efficacy in reducing oxidative stress and inflammation during pregnancy and currently in clinical trials, was used to test its transfer rate across both feto-maternal interfaces. The data obtained from FMi-PLA-OOC were compared with existing data from in vivo animal models and ex vivo placenta perfusion models. Additionally, we employed mechanistically based simulation software (Gastroplus®) to predict pravastatin pharmacokinetics in pregnant subjects based on validated nonpregnant drug data. Results: Pravastatin transfer across the FMi-PLA-OOC and predicted pharmacokinetics in the in silico models were found to be similar, approximately 18%. In contrast, animal models showed supraphysiologic drug accumulation in the amniotic fluid, reaching approximately 33%. Discussion: The results from this study suggest that the FMi-PLA-OOC and in silico models can serve as alternative methods for studying drug pharmacokinetics during pregnancy, providing valuable insights into drug transport and metabolism across the placenta and fetal membranes. These advanced platforms offer promising opportunities for safe, reliable, and faster testing of therapeutic compounds, potentially reducing the number of pregnant women referred to as "therapeutic orphans" due to the lack of consideration in drug development and clinical trials. By bridging the gap between preclinical studies and clinical trials, these approaches hold great promise in improving maternal and neonatal health outcomes.

Simultaneous LC-MS/MS quantification of SGLT2 inhibitors and antipyrine in medium and tissue from human ex vivo placenta perfusions

A liquid chromatography – tandem mass spectrometry (LC-MS/MS) method has been developed to simultaneously measure four sodium glucose co-transporter 2 (SGLT2) inhibitors and the transfer marker antipyrine (ANTI) in perfusion medium and placental tissue collected from ex vivo human placental perfusions. The four SGLT2 inhibitors were empagliflozin (EMPA), dapagliflozin (DAPA), ertugliflozin (ERTU) and canagliflozin (CANA). Chromatographic separation was achieved on an Uptisphere® C18 reversed phase column (50 mm × 4.6 mm × 5 µm) within 2.85 min, using a gradient elution with 10 mM ammonium formate in water (mobile phase A) and acetonitrile (mobile phase B) both with 0.1% formic acid. Analysis of ammonium adduct ions was performed on an AB SCIEX 6500+ triple quadrupole mass spectrometer using positive electrospray ionisation and scheduled multiple reaction monitoring (sMRM). The transitions were m/z 468.00 → 355.20 (EMPA), m/z 426.00 → 167.20 (DAPA), m/z 437.10 → 206.90 (ERTU), m/z 462.00 → 249.00 (CANA) and m/z 189.20 → 55.90 (ANTI).The method was validated according to the European Medicines Agency guidelines and was proven to be selective, linear within a concentration range of 1–1000 µg/L (DAPA, CANA, ANTI) and 1–500 µg/L (EMPA, ERTU), accurate, precise and free of carry-over, instabilities, recovery and matrix effect issues.This newly developed method is suitable to analyse perfusion medium and placenta tissue samples collected during ex vivo human placenta perfusions. It thereby enables quantification of transport across the placental barrier of the SGLT2 inhibitors EMPA, DAPA, ERTU and CANA as well as the transfer marker ANTI.

Placenta-on-a-Chip as an In Vitro Approach to Evaluate the Physiological and Structural Characteristics of the Human Placental Barrier upon Drug Exposure: A Systematic Review.

Quantification of fetal drug exposure remains challenging since sampling from the placenta or fetus during pregnancy is too invasive. Currently existing in vivo (e.g., cord blood sampling) and ex vivo (e.g., placenta perfusion) models have inherent limitations. A placenta-on-a-chip model is a promising alternative. A systematic search was performed in PubMed on 2 February 2023, and Embase on 14 March 2023. Studies were included where placenta-on-a-chip was used to investigate placental physiology, placenta in different obstetric conditions, and/or fetal exposure to maternally administered drugs. Seventeen articles were included that used comparable approaches but different microfluidic devices and/or different cultured maternal and fetal cell lines. Of these studies, four quantified glucose transfer, four studies evaluated drug transport, three studies investigated nanoparticles, one study analyzed bacterial infection and five studies investigated preeclampsia. It was demonstrated that placenta-on-a-chip has the capacity to recapitulate the key characteristics of the human placental barrier. We aimed to identify knowledge gaps and provide the first steps towards an overview of current protocols for developing a placenta-on-a-chip, that facilitates comparison of results from different studies. Although models differ, they offer a promising approach for in vitro human placental and fetal drug studies under healthy and pathological conditions.

Perfused rat term placenta as a preclinical model to investigate placental dopamine and norepinephrine transport.

The placenta represents a non-neuronal organ capable of transporting and metabolizing monoamines. Since these bioactive molecules participate in numerous processes essential for placental and fetal physiology, any imbalance in their levels during pregnancy may affect brain development, projecting a higher risk of behavioral disorders in childhood or adulthood. Notably, the monoamine system in the placenta is a target of various psychoactive drugs and can be disrupted in several pregnancy pathologies. As research in pregnant women poses significant ethical restrictions, animal models are widely employed to study monoamine homeostasis as a mechanism involved in fetal programming. However, detailed knowledge of monoamine transport in the rat placenta is still lacking. Moreover, relatability to the human placental monoamine system is not examined. The present study provides insights into the transplacental monoamine dynamics between maternal and fetal circulation. We show that norepinephrine maternal-to-fetal transport is <4% due to high metabolism within the trophoblast. In contrast, dopamine maternal-to-fetal transport exceeds 25%, likely through passive transport across the membrane. In addition, we show high clearance of norepinephrine and dopamine from the fetal circulation mediated by the organic cation transporter 3 (OCT3). Altogether, we present transcriptional and functional evidence that the in situ rat placenta perfusion represents a suitable model for (patho)physiological investigation of dopamine and norepinephrine homeostasis in the fetoplacental unit. With the rapid advancements in drug discovery and environmental toxicity, the use of rat placenta as a preclinical model could facilitate screening of possible xenobiotic effects on monoamine homeostasis in the placenta.

Placenta-derived extracellular vesicles from preeclamptic and healthy pregnancies impair ex vivo vascular endothelial function.

Preeclampsia (PE) is a pregnancy syndrome characterized by new-onset hypertension and end-organ dysfunction. The pathophysiology of PE remains undetermined, but it is thought that maternal vascular dysfunction plays a central role, potentially due, in part, to the release of syncytiotrophoblast-derived extracellular vesicles (STBEVs) into the maternal circulation by a dysfunctional placenta. STBEVs from normal pregnancies (NP) impair vascular function, but the effect of PE STBEVs (known to differ in composition with elevated circulating levels) on vascular function are not known. We hypothesized that PE STBEVs have more detrimental effects on vascular function compared with NP STBEVs. STBEVs were collected by perfusion of placentas from women with NP or PE. Mesenteric arteries from pregnant rats were incubated overnight with NP or PE STBEVs, and vascular function was assessed by wire myography. NP and PE STBEVs impaired endothelial function, partially by reducing nitric oxide (NO) bioavailability. Incubation of human umbilical vein endothelial cells with NP and PE STBEVs increased nuclear factor κ-light-chain-enhancer of activated B cell (NF-κB) activation, reactive oxygen species, nitrotyrosine levels, and reduced NO levels. However, PE STBEVs increased NF-κB activation and nitrotyrosine levels to a lesser extent than NP STBEVs. Taken together, no greater impact of PE STBEVs compared with NP STBEVs on endothelial function was found. However, the impaired vascular function by PE STBEVs and increased levels of STBEVs in PE suggest PE STBEVs may contribute to maternal vascular dysfunction in PE. Our study further expands on the potential mechanisms that lead to adverse outcomes in PE and provides potential targets for future interventions.