Grafmüller Stefanie, Manser Pius, Krug Harald F, Wick Peter, von Mandach Ursula
Department of Obstetrics, Perinatal Pharmacology, University Hospital Zurich.
J Vis Exp. 2013 Jun 18(76):50401. doi: 10.3791/50401.
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.
几十年前，人们认为人类胎盘是母亲与未出生胎儿之间不可逾越的屏障。然而，沙利度胺致胎儿出生缺陷的发现以及随后的许多研究证明事实恰恰相反。如今，已有研究表明，尼古丁、海洛因、美沙酮等多种有害的外源性物质以及药物和环境污染物都能穿透这一屏障。随着纳米技术的广泛应用，胎盘很可能会通过接触意外地与新型纳米颗粒接触，或者在潜在的纳米医学应用中有意接触。由于胎盘是最具物种特异性的哺乳动物器官（1），动物实验的数据不能外推至人类。因此，1967年由帕尼热尔等人开发（2）并于1972年由施耐德等人不断改进（3）的离体双循环人胎盘灌注法，可作为研究外源性物质或颗粒转运的理想模型。在此，我们重点关注离体双循环人胎盘灌注方案及其进一步发展，以获得可重复的结果。胎盘是在征得母亲知情同意后，从行剖宫产的足月正常妊娠中获取的。将完整小叶的胎儿和母体血管插管并灌注至少5小时。作为模型颗粒，将直径为80和500 nm的荧光标记聚苯乙烯颗粒添加到母体循环中。80 nm的颗粒能够穿过胎盘屏障，是一种穿过胎盘转运至胎儿的物质的完美示例，而500 nm的颗粒则保留在胎盘组织或母体循环中。离体人胎盘灌注模型是少数几个能在重要组织屏障处提供有关外源性物质转运行为可靠信息的模型之一，这些信息具有预测性且与临床相关。
