Oocyte vitrification/storage/handling/transportation/warming, effect on survival and clinical results in donation programmes

Abstract

SummaryNowadays human gamete and embryo cryopreservation is integral to Assisted Reproductive (AR) techniques in optimizing treatment management and results. Cryopreserved cells can be stored for years and transported between authorized AR centres. Particularly in the case of heterologous insemination techniques, the use of frozen gametes facilitates donor/recipient matching and allows time for donor testing. Cryopreserved oocytes, spermatozoa and embryos can be shipped between specialized donation and cryopreservation centres (gamete cryobanks) and AR centres carrying out treatment on recipient patients. However, appropriate procedures need to be in place to minimize physical shocks and contamination during cryostorage, handling and shipping. The aim of the meeting "Shipping Gametes and Embryos" held in Milan on February 4 th , 2017 was to address these critical aspects, including regulation and legal requirements, and to propose some troubleshooting procedures in the case of emergencies. A specific example of the possible negative impact of handling and transportation on survival of oocytes shipped between Spain and Italy was reported during the meeting: an inappropriate method of shipping reduced by 20% the vitrified oocytes' survival at warming. The influence of different transportation methods and, in addition, the impact of the number of surviving oocytes used are described in detail through the analysis of original data presented for the first time at this meeting and reported in this article. The general suggestion emerging from this study is to take into account the possible negative impact of handling and different transportation methods on survival at warming and to assign an adequate number of oocytes per treatment, in order to inject a minimum of five oocytes.

Human Reproductive Cell Cryopreservation, Storage, Handling, and Transport: Risks and Risk Management

“…They speculated that this effect was likely due to one of many abnormal conditions during shipping, including vessels being exposed to elevated temperatures and air pressure, vibration/other physical shock, and horizontal storage. 43 In the study of Parmegiani et al, 44 shipping temperature and type of transportation appeared to impact survival of vitrified oocytes transported from Spain to Italy. It was the experience of these investigators that road courier was the safest means of transportation; in their case, the shipper was filled with liquid nitrogen rather than "charged" with nitrogen vapor, though this is not necessarily common practice globally.…”

“…During transport by air (where liquid nitrogen onboard is not permitted due to its hazardous material designation), despite the shipper temperature being recorded below the safe threshold of À180°C in both cargo and cabin baggage, both locations seemed to negatively affect oocyte survival, which decreased by up to 20% compared with oocytes transported by road. 44 The reasons for this decline are unclear and will remain speculative until the conditions are replicated experimentally and investigated in detail.…”

“…The three studies cited earlier 43,44,47 should draw attention to the importance of continuous monitoring of conditions via electronic data loggers throughout the shipper's journey rather than relying on single data points collected at final destination using, for instance, thermal exposure indicators that change color when exposed to temperatures above a designated threshold (e.g., Cryoguard; Cryoguard Corporation, Colmar, PA), however convenient the latter may be. It is equally important to determine the most appropriate position for the temperature probe inside the transportation vessel.…”

Cryostorage of human gametes and embryos: a reckoning

“…The second study is by Parmegiani et al (2017). They examined shipment by plane (hold or cabin baggage) or road courier, demonstrating significant differences in survival of vitrified eggs among these groups.…”

“…Although this may seem like an exaggerated exercise, it is relevant to conditions created during non-automated inventory of cryostorage dewars or sample identification procedures conducted routinely by ART laboratories, egg banks, and other gamete and embryo repositories. The experimental design is also relevant to the multiple handling steps involved in shipment of samples, from preparation by the sender to final disposition by the receiver (Parmegiani et al, 2017).…”