Vajta Gábor, Rienzi Laura, Ubaldi Filippo Maria
BGI Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen, China; Central Queensland University, Bruce Highway, Rockhampton, Queensland, Australia.
Clinica Valle Giulia, G.E.N.E.R.A. Centre for Reproductive Medicine, Via G. De Notaris 2b, Rome, Italy.
Reprod Biomed Online. 2015 Apr;30(4):325-33. doi: 10.1016/j.rbmo.2014.12.012. Epub 2015 Jan 12.
Vitrification is now the dominant approach for cryopreservation of human oocytes and embryos; however, serious disagreement persists, particularly about biosafety issues. Techniques are categorized as either 'open' or 'closed' according to occurrence of direct contact between the medium and liquid nitrogen during cryopreservation. Advocates of closed systems emphasize the potential danger of disease transmission mediated through liquid nitrogen, and praise the safety of their approach; those who use the open systems refer to the lack of evidence of disease transmission and regard their systems as more consistent and efficient. The purpose of this review is to clarify whether open and closed systems are really open and closed; if closed systems are safe and free of any danger of contamination; if closed systems are equally efficient as open ones for cryopreservation of human embryos and oocytes by considering overall outcome; and finally, if ethical and legal concerns are sound when risks and benefits are considered in a broader sense. On the basis of these answers, implementation of rational measures to lower the theoretical danger of disease transmission are proposed while maintaining the achievements in cryopreservation that have contributed substantially to the advancement in assisted reproduction techniques during the past decade.
玻璃化冷冻法目前是人类卵母细胞和胚胎冷冻保存的主要方法；然而，严重的分歧依然存在，尤其是在生物安全问题上。根据冷冻保存过程中培养基与液氮之间是否发生直接接触，技术可分为“开放式”或“封闭式”。封闭式系统的支持者强调液氮介导疾病传播的潜在危险，并称赞其方法的安全性；使用开放式系统的人则指出缺乏疾病传播的证据，并认为他们的系统更稳定且高效。本综述的目的是阐明开放式和封闭式系统是否真的开放和封闭；封闭式系统是否安全且没有任何污染风险；通过考虑总体结果，封闭式系统在人类胚胎和卵母细胞冷冻保存方面是否与开放式系统同样高效；最后，从更广泛的意义上考虑风险和收益时，伦理和法律方面的担忧是否合理。基于这些答案，在保持过去十年冷冻保存所取得的成就（这些成就极大地推动了辅助生殖技术的进步）的同时，提出实施合理措施以降低疾病传播的理论风险。
