Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

Stefanie Grafmüller; Pius Manser; Harald F. Krug; Peter Wick; Ursula von Mandach

doi:10.3791/50401

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Method Article

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

17.1K views

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DOI:

10.3791/50401

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June 18th, 2013

Stefanie Grafmüller¹^,²^,³ , Pius Manser² , Harald F. Krug² , Peter Wick² , Ursula von Mandach¹

¹Department of Obstetrics, Perinatal Pharmacology, University Hospital Zurich, ²Laboratory for Materials - Biology Interactions, EMPA Swiss Federal Laboratories for Materials Testing and Research, ³Graduate School for Cellular and Biomedical Sciences, University of Bern

Summary

The ex vivo dual recirculating human placental perfusion model can be used to investigate the transfer of xenobiotics and nanoparticles across the human placenta. In this video protocol we describe the equipment and techniques required for a successful execution of a placenta perfusion.

Abstract

Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced birth defects and many later studies afterwards proved the opposite. Today several harmful xenobiotics like nicotine, heroin, methadone or drugs as well as environmental pollutants were described to overcome this barrier. With the growing use of nanotechnology, the placenta is likely to come into contact with novel nanoparticles either accidentally through exposure or intentionally in the case of potential nanomedical applications. Data from animal experiments cannot be extrapolated to humans because the placenta is the most species-specific mammalian organ ¹. Therefore, the ex vivo dual recirculating human placental perfusion, developed by Panigel et al. in 1967 ² and continuously modified by Schneider et al. in 1972 ³, can serve as an excellent model to study the transfer of xenobiotics or particles.

Here, we focus on the ex vivo dual recirculating human placental perfusion protocol and its further development to acquire reproducible results.

The placentae were obtained after informed consent of the mothers from uncomplicated term pregnancies undergoing caesarean delivery. The fetal and maternal vessels of an intact cotyledon were cannulated and perfused at least for five hours. As a model particle fluorescently labelled polystyrene particles with sizes of 80 and 500 nm in diameter were added to the maternal circuit. The 80 nm particles were able to cross the placental barrier and provide a perfect example for a substance which is transferred across the placenta to the fetus while the 500 nm particles were retained in the placental tissue or maternal circuit. The ex vivo human placental perfusion model is one of few models providing reliable information about the transport behavior of xenobiotics at an important tissue barrier which delivers predictive and clinical relevant data.

Introduction

The placenta is a complex organ which is responsible for the exchange of oxygen, carbon dioxide, nutrients and waste products and at the same time able to keep the two blood circuits of the mother and the growing fetus separated from each other. Additionally, it prevents rejection of the child by the maternal immune system and secretes hormones to maintain pregnancy. The cellular barrier is formed by the cytotrophoblast cells which fuse and form a true syncytium without lateral cell membranes ^4,5. The whole placenta is organized in several cotyledons, which contain one fetal villous tree and represent one functional unit of the placenta.