by Dr. Beniamino Sadun
Since the first cord blood transplantation (performed in 1988 on a 6-year-old child affected by Fanconi anemia), the use of cord blood in medicine has grown considerably. Over 20,000 cord blood transplants have been performed worldwide and approximately 3,000 patients are treated with cord blood annually for over 80 pathologies including hematological disorders, inborn errors of metabolism, various kinds of solid cancers, osteopetrosis and cerebral palsy, among others. This number is likely to grow with expected breakthroughs in regenerative medicine research. As a consequence, in the last decade, we have assisted in an explosion of private cord blood banks around the globe. In the US alone, there are currently over 35 private banks offering their service to expecting parents.
However, not all private banks are the same. Technological choices made by the bank can have tremendous long-term effects on you baby’s cord blood stem cells. For example, it is now scientifically proven that the number of cells used in cord blood treatments determine recovery and survival following the transplantation. The lowest acceptable cell dose should ideally be between 15 and 20 million nucleated cells per kilogram of body weight, which is why it is so important that samples containing these precious cells are processed, frozen and stored using the best technology. Every cell counts: even a small difference in recovery and viability rates can dramatically change the clinical outcome of the transplantation.
The most sophisticated system for cord blood banking to date is the Bioarchive® robotic system. This is a closed system as opposed to the conventional open systems currently used in many of the older cord blood banks. An open system poses the risk of transient warming events (TWE) each time a rack of samples is lifted out of the tank to place a new one inside. This can happen hundreds of times during the process of filling the rack with samples and removing samples, with dangerous consequences on cell viability. In the closed Bioarchive® system, the samples are transferred one at a time into the tank with a robotic arm, leaving all other samples undisturbed during the process, thus avoiding exposure to the external environment. For additional safety and security, the BioArchive® system utilizes multicompartment cryobags with a Teflon™ overwrap to ensure sample integrity and to eliminate the risk of sample cross-contamination. In conventional systems, there is a possible risk of cross-contamination between vials or bags without an overwrap. To avoid this risk, these banks use vapour phase storage tanks. However these types of tanks are associated with an even higher risk of transient warming events.
Samples in a cord blood bank can theoretically be stored in liquid nitrogen indefinitely. It has been estimated that, if kept stable and undisturbed, they remain viable for many decades.
Dr. Beniamino Sadun is a Medical Doctor with a Post-graduate degree in Hygiene and Preventive Medicine. He currently serves as Director of Research and Development of AssureImmune, a stem cell cryopreservation company headquartered in Boca Raton (FL).
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