Shariq Ali

Transport of digoxin-loaded polymeric nanoparticles across BeWo cells, an in vitro model of human placental trophoblast

BACKGROUND Fetal arrhythmias can lead to fetal congestive heart failure and hydrops fetalis. Digoxin (the first-line treatment) has low transplacental permeability and high risk of maternal side effects. Biodegradable digoxin-loaded PEGylated poly(lactic-co-glycolic acid) nanoparticles may increase digoxin transport across BeWo b30 cell monolayers (an in vitro model of trophoblast in human placenta) by reducing the drugs interaction with P-gp. Results/methodology: The nanoparticles showed high encapsulation efficiency and sustained release over 48 h. Transport studies revealed significantly increased permeability across BeWo cell layers of digoxin-loaded nanoparticles when compared with free digoxin. P-gp inhibition also increased the permeability of digoxin, but not digoxin-loaded nanoparticles. CONCLUSION This represents a novel treatment strategy for fetal cardiovascular disease which may improve maternal and fetal outcomes.

Influences of Nanomaterials on the Barrier Function of Epithelial Cells

Recent advances in nanotechnology have led to exciting opportunities in medicine, energy, manufacturing, and other fields. Nevertheless, it is important to adequately assess the potential impacts of nanomaterial exposure. This chapter focuses on the interactions of nanomaterials with epithelial barriers in the lungs, intestine, kidneys, skin, and placenta. Methods for determining transepithelial electrical resistance and paracellular permeability are described. Effects on cell viability and barrier integrity depend on the chemical nature of the nanomaterial, nanoparticle size, surface coatings, and concentration. Disruption of tight junctions can affect permeability and interfere with normal regulatory processes of the epithelial barrier. Future research is needed to better understand the possibilities and the limits of novel approaches in nanotechnology.

Placental control of drug delivery

&NA; The placenta serves as the interface between the maternal and fetal circulations and regulates the transfer of oxygen, nutrients, and waste products. When exogenous substances are present in the maternal bloodstream—whether from environmental contact, occupational exposure, medication, or drug abuse—the extent to which this exposure affects the fetus is determined by transport and biotransformation processes in the placental barrier. Advances in drug delivery strategies are expected to improve the treatment of maternal and fetal diseases encountered during pregnancy. Graphical abstract Figure. No caption available.

Cytotoxicity of Endocytosis and Efflux Inhibitors in the BeWo Cell Line

Aims The purpose of this study was to determine the cell viability and cytotoxicity of various endocytosis and efflux inhibitors which can be used to determine transport and uptake mechanisms in the BeWo (b30 clone) human placental trophoblast cell line. Ethanol and dimethylsulfoxide (DMSO) were also studied since they are often used as cosolvents for administration of these inhibitors. Methodology The water-soluble tetrazolium-1 (WST-1) assay was used to quantify cell viability and the lactate dehydrogenase (LDH) assay was used to determine cytotoxicity. Results By the WST-1 assay, reduced cell viability was observed following 4 hours of exposure to chlorpromazine (10 μg/mL), colchicine (1 mM), filipin (3 μg/mL), gentamicin (2 mM), GF120918 (1 μM), methyl-β-cyclodextrin (5 mM), and verapamil (100 μM). By the LDH assay, however, no cytotoxicity was observed after 4 hours of exposure to the aforementioned compounds. Amiloride (500 μM), ethanol (up to 0.1% v/v), and DMSO (up to 0.1% v/v) did not reduce cell viability nor induce cytotoxicity. Conclusion This information is valuable when selecting potential inhibitors of endocytosis and efflux and the selection of time points for mechanistic studies.

HPLC Method Development for Quantification of Doxorubicin in Cell Culture and Placental Perfusion Media

Assessment of drug transport across the placenta is important in understanding the effect of drugs on placental and fetal health. These phenomena can be studied in both in vitro cell lines and ex vivo placental perfusions. We have successfully developed a sensitive yet simple high performance liquid chromatography (HPLC) method coupled with fluorescence detection to determine the concentration of doxorubicin (DXR) in cell culture media for transport studies in human trophoblast cells (BeWo, b30 clone) and in fetal media for placental perfusion experiments. The method was developed based on a protein precipitation technique and was validated in both media types for linearity, intra-day, and inter-day precision and accuracy. The relationship of peak area to concentration was linear with R2 values of 0.99 or greater obtained over the concentration range of 1.5 to 15,000 ng/mL. Despite the high concentrations of albumin in fetal perfusion media (30 mg/mL), the lower limits of detection and quantification for DXR were found to be 1.5 and 5 ng/mL, respectively. This analytical method may be used to study the transport of DXR across BeWo cells and human placenta during placental perfusion studies.

Determination of the transplacental transfer of paclitaxel and antipyrine by high performance liquid chromatography coupled with photodiode array detector

ABSTRACT Ex vivo placental perfusion experiments are important in understanding the quantity and mechanisms of xenobiotic transport to the fetus during pregnancy. Our study demonstrates that paclitaxel and antipyrine concentrations in placental perfusion medium containing physiological concentrations of human serum albumin during pregnancy (30 mg/mL) can be quantified by RP-HPLC and UV detection. A liquid-liquid extraction method was developed for the quantification of paclitaxel and celecoxib (internal standard) from perfusion medium. Antipyrine, which is a necessary marker in placental perfusions for determining the validity of experiments and calculating the clearance index of xenobiotics, was also analyzed by HPLC and UV detection. Antipyrine concentrations were determined by HPLC after precipitating the perfusion medium in acetonitrile and separating the precipitated proteins by centrifugation. Concentrations were fitted to linear regressions with R2 values approaching 1. Lower limits of detection for paclitaxel and antipyrine were 100 ng/mL and 200 ng/mL, respectively. Both methods demonstrated high intra-day and inter-day precision and trueness. Additionally, the use of these methods was demonstrated in a placental perfusion experiment using Taxol® (paclitaxel dissolved in Cremophor-EL). The fetal transfer rate of Taxol was 6.6% after 1 hour. GRAPHICAL ABSTRACT