An update on placental drug transport and its relevance to fetal drug exposure

The Application of Nano Drug Delivery Systems in Female Upper Genital Tract Disorders

The prevalence of female reproductive system disorders is increasing, especially among women of reproductive age, significantly impacting their quality of life and overall health. Managing these diseases effectively is challenging due to the complex nature of the female reproductive system, characterized by dynamic physiological environments and intricate anatomical structures. Innovative drug delivery approaches are necessary to facilitate the precise regulation and manipulation of biological tissues. Nanotechnology is increasingly considered to manage reproductive system disorders, for example, nanomaterial imaging allows for early detection and enhances diagnostic precision to determine disease severity and progression. Additionally, nano drug delivery systems are gaining attention for their ability to target the reproductive system successfully, thereby increasing therapeutic efficacy and decreasing side effects. This comprehensive review outlines the anatomy of the female upper genital tract by highlighting the complex mucosal barriers and their impact on systemic and local drug delivery. Advances in nano drug delivery are described for their sustainable therapeutic action and increased biocompatibility to highlight the potential of nano drug delivery strategies in managing female upper genital tract disorders.

The Role of ABCB1, ABCG2, and SLC Transporters in Pharmacokinetic Parameters of Selected Drugs and Their Involvement in Drug-Drug Interactions

Membrane transporters are expressed in a wide range of tissues in the human organism. These proteins regulate the penetration of various substances such as simple ions, xenobiotics, and an extensive number of therapeutics. ABC and SLC drug transporters play a crucial role in drug absorption, distribution, and elimination. Recent decades have shown their contribution to the systemic exposure and tissue penetration of numerous drugs, thereby having an impact on pharmacokinetic and pharmacodynamic parameters. Importantly, the activity and expression of these transporters depend on numerous conditions, including intestinal microbiome profiles or health conditions. Moreover, the combined intake of other drugs or natural agents further affects the functionality of these proteins. In this review, we will discuss the involvement of ABC and SLC transporters in drug disposition. Moreover, we will present current evidence of the potential role of drug transporters as therapeutic targets.

Delivery of PAMAM dendrimers and dendriplexes across natural barriers (blood-brain barrier and placental barrier) in healthy pregnant mice

Gene therapy is an important tool for treating fetal diseases that allows for the delivery and integration of therapeutic genes into the genome of cells carrying mutations. Nanomolecules, like PAMAM dendrimers, have recently come into wider use for carrying vectors as they have several advantages over viral vectors. Namely, (1) tunable size and surface chemistry, (2) uniform size, (3) the ability to target specific tissues, and (4) the ability to carry large biomolecules and drugs. Recently, we demonstrated that 4th generation (G4) PAMAM dendrimer with a cystamine core and a non-toxic surface having 90% -OH and 10% -NH2 groups (D-Cys) could cross the blood-brain barrier following injection into the bloodstream. In the current study, as a proof of concept, we delivered the dendrimers alone (D-Cys) tagged with Cy5.5 (D-Cys-cy5.5) to healthy pregnant C57BL/6J mice to determine the fate of these dendrimers in the pregnant mice as well as in the fetus. Systematic diffusion of the D-Cys-cy5.5 was evaluated on gestational day 17 (3 days after injection) using in vivo imaging. This revealed that the dendrimer was taken up into circulation and away from the injection site. Analysis of sections by fluorescence microscopy showed that D-Cys-cy5.5 was able to successfully cross the maternal blood-brain barrier. However, analysis of the fetal brains failed to detect dendrimers in the central nervous system (CNS). Instead, they appeared to be retained in the placenta. This is one of the first studies to analyze the distribution of surface-modified PAMAM dendrimer in the pregnant mouse and fetus following systemic injection.

Actively Targeted Nanomedicines: A New Perspective for the Treatment of Pregnancy-Related Diseases

More than 20% of pregnant women experience serious complications during pregnancy, that gravely affect the safety of both the mother and the child. Due to the unique state of pregnancy, medication during pregnancy is subject to various restrictions. Nanotechnology is an emerging technology that has been the focus of extensive medical research, and great progress has recently been made in developing sensitive diagnostic modalities and efficient medical treatment. Accumulating evidence has shown that nanodrug delivery systems can significantly improve the targeting, reduce the toxicity and improve the bioavailability of drugs. Recently, some actively targeted nanomedicines have been explored in the treatment of pregnancy-related diseases. This article reviews common types of nanocarriers and active targeting ligands in common pregnancy-related diseases and complications such as preeclampsia, preterm birth, fetal growth restriction, and choriocarcinoma. Finally, the challenges and future prospects in the development of these nanomaterials are discussed, with the aim of providing guidance for future research directions.

Safety and Efficacy of Antiviral Drugs and Vaccines in Pregnant Women: Insights from Physiologically Based Pharmacokinetic Modeling and Integration of Viral Infection Dynamics

Addressing the complexities of managing viral infections during pregnancy is essential for informed medical decision-making. This comprehensive review delves into the management of key viral infections impacting pregnant women, namely Human Immunodeficiency Virus (HIV), Hepatitis B Virus/Hepatitis C Virus (HBV/HCV), Influenza, Cytomegalovirus (CMV), and SARS-CoV-2 (COVID-19). We evaluate the safety and efficacy profiles of antiviral treatments for each infection, while also exploring innovative avenues such as gene vaccines and their potential in mitigating viral threats during pregnancy. Additionally, the review examines strategies to overcome challenges, encompassing prophylactic and therapeutic vaccine research, regulatory considerations, and safety protocols. Utilizing advanced methodologies, including PBPK modeling, machine learning, artificial intelligence, and causal inference, we can amplify our comprehension and decision-making capabilities in this intricate domain. This narrative review aims to shed light on diverse approaches and ongoing advancements, this review aims to foster progress in antiviral therapy for pregnant women, improving maternal and fetal health outcomes.

ABC Efflux Transporters and Solute Carriers in the Early Developing Brain of a Marsupial Monodelphis domestica (South American Gray Short-Tailed Opossum)

This study used a marsupial Monodelphis domestica, which is born very immature and most of its development is postnatal without placental protection. RNA-sequencing (RNA-Seq) was used to identify the expression of influx and efflux transporters (ATP-binding cassettes [ABCs] and solute carriers [SLCs]) and metabolizing enzymes in brains of newborn to juvenile Monodelphis. Results were compared to published data in the developing eutherian rat. To test the functionality of these transporters at similar ages, the entry of paracetamol (acetaminophen) into the brain and cerebrospinal fluid (CSF) was measured using liquid scintillation counting following a single administration of the drug along with its radiolabelled tracer [3H]. Drug permeability studies found that in Monodelphis, brain entry of paracetamol was already restricted at P5; it decreased further in the first week of life and then remained stable until the oldest age group tested (P110). Transcriptomic analysis of Monodelphis brain showed that expression of transporters and their metabolizing enzymes in early postnatal (P) pups (P0, P5, and P8) was relatively similar, but by P109, many more transcripts were identified. When transcriptomes of newborn Monodelphis brain and E19 rat brain and placenta were compared, several transporters present in the rat placenta were also found in the newborn Monodelphis brain. These were absent from E19 rat brain but were present in the adult rat brain. These data indicate that despite its extreme immaturity, the newborn Monodelphis brain may compensate for the lack of placental protection during early brain development by upregulating protective mechanisms, which in eutherian animals are instead present in the placenta.

Fetus Exposure to Drugs and Chemicals: A Holistic Overview on the Assessment of Their Transport and Metabolism across the Human Placental Barrier

BACKGROUND

The placenta exerts a crucial role in fetus growth and development during gestation, protecting the fetus from maternal drugs and chemical exposure. However, diverse drugs and chemicals (xenobiotics) can penetrate the maternal placental barrier, leading to deleterious, adverse effects concerning fetus health. Moreover, placental enzymes can metabolize drugs and chemicals into more toxic compounds for the fetus. Thus, evaluating the molecular mechanisms through which drugs and chemicals transfer and undergo metabolism across the placental barrier is of vital importance. In this aspect, this comprehensive literature review aims to provide a holistic approach by critically summarizing and scrutinizing the potential molecular processes and mechanisms governing drugs and chemical transfer and metabolism across the placental barrier, which may lead to fetotoxicity effects, as well as analyzing the currently available experimental methodologies used to assess xenobiotics placental transfer and metabolism.

METHODS

A comprehensive and in-depth literature review was conducted in the most accurate scientific databases such as PubMed, Scopus, and Web of Science by using relevant and effective keywords related to xenobiotic placental transfer and metabolism, retrieving 8830 published articles until 5 February 2024. After applying several strict exclusion and inclusion criteria, a final number of 148 relevant published articles were included.

RESULTS

During pregnancy, several drugs and chemicals can be transferred from the mother to the fetus across the placental barrier by either passive diffusion or through placental transporters, resulting in fetus exposure and potential fetotoxicity effects. Some drugs and chemicals also appear to be metabolized across the placental barrier, leading to more toxic products for both the mother and the fetus. At present, there is increasing research development of diverse experimental methodologies to determine the potential molecular processes and mechanisms of drug and chemical placental transfer and metabolism. All the currently available methodologies have specific strengths and limitations, highlighting the strong demand to utilize an efficient combination of them to obtain reliable evidence concerning drug and chemical transfer and metabolism across the placental barrier. To derive the most consistent and safe evidence, in vitro studies, ex vivo perfusion methods, and in vivo animal and human studies can be applied together with the final aim to minimize potential fetotoxicity effects.

CONCLUSIONS

Research is being increasingly carried out to obtain an accurate and safe evaluation of drug and chemical transport and metabolism across the placental barrier, applying a combination of advanced techniques to avoid potential fetotoxic effects. The improvement of the currently available techniques and the development of novel experimental protocols and methodologies are of major importance to protect both the mother and the fetus from xenobiotic exposure, as well as to minimize potential fetotoxicity effects.

Monte Carlo Optimization Method Based QSAR Modeling of Placental Barrier Permeability

PURPOSE

In order to ensure that drug administration is safe during pregnancy, it is crucial to have the possibility to predict the placental permeability of drugs in humans. The experimental method which is most widely used for the said purpose is in vitro human placental perfusion, though the approach is highly expensive and time consuming. Quantitative structure-activity relationship (QSAR) modeling represents a powerful tool for the assessment of the drug placental transfer, and can be successfully employed to be an alternative in in vitro experiments.

METHODS

The conformation-independent QSAR models covered in the present study were developed through the use of the SMILES notation descriptors and local molecular graph invariants. What is more, the Monte Carlo optimization method, was used in the test sets and the training sets as the model developer with three independent molecular splits.

RESULTS

A range of different statistical parameters was used to validate the developed QSAR model, including the standard error of estimation, mean absolute error, root-mean-square error (RMSE), correlation coefficient, cross-validated correlation coefficient, Fisher ratio, MAE-based metrics and the correlation ideality index. Once the mentioned statistical methods were employed, an excellent predictive potential and robustness of the developed QSAR model was demonstrated. In addition, the molecular fragments, which are derived from the SMILES notation descriptors accounting for the decrease or increase in the investigated activity, were revealed.

CONCLUSION

The presented QSAR modeling can be an invaluable tool for the high-throughput screening of the placental permeability of drugs.

Changes in Expression and Function of Placental and Intestinal P-gp and BCRP Transporters during Pregnancy

ABC transporters are ubiquitous in the human body and are responsible for the efflux of drugs. They are present in the placenta, intestine, liver and kidney, which are the major organs that can affect the pharmacokinetic and pharmacologic properties of drugs. P-gp and BCRP transporters are the best-characterized transporters in the ABC superfamily, and they have a pivotal role in the barrier tissues due to their efflux mechanism. Moreover, during pregnancy, drug efflux is even more important because of the developing fetus. Recent studies have shown that placental and intestinal ABC transporters have great importance in drug absorption and distribution. Placental and intestinal P-gp and BCRP show gestational-age-dependent expression changes, which determine the drug concentration both in the mother and the fetus during pregnancy. They may have an impact on the efficacy of antibiotic, antiviral, antihistamine, antiemetic and oral antidiabetic therapies. In this review, we would like to provide an overview of the pharmacokinetically relevant expression alterations of placental and intestinal ABC transporters during pregnancy.