How To Unfreeze Cryopreserved Organs: New Technology Thaws Heart, Kidneys With Minimal Risk Of Tissue Damage
A groundbreaking discovery in the field of cryopreservation could soon be used to speed up the organ transplant process and potentially save millions of lives.
Research reveals a new technology of bringing cryopreserved tissue back to life, which tests have deemed more efficient than the methods currently available for tissue preservation.
Short-term cryogenic technologies are already being successfully used in transplant biology to preserve harvested organs and tissue. This elaborated process involves preserving the biological samples in a vitrified (glassy) state until they are ready to be thawed and prepared for transplant.
However, unfreezing the samples after vitrification can sometimes prove a daunting task, as the warming process can result in tissue damage. Consequently, currently used thawing methods are not a viable option for long-term cryopreservation of tissue and organs.
Setting out to fix this problem, researchers from the University of Minnesota have created a nanoparticle warming technology that leaves biological samples intact, avoiding any potential tissue damage typically associated with unfreezing.
This novel method, featured in the journal Science Translational Medicine, represents an important milestone in organ transplant, making it possible for cryopreserved tissues to be used in long-term situations.
Paving The Way For Cryopreserved Organ Banking
The researchers have already tested their technology on heart valves and blood vessels with no damage to the thawed tissue, and they believe it could soon be used to create organ banks of cryopreserved human hearts and kidneys. This would make the organs promptly available for transplant with considerable benefits to patients.
Kelvin G.M. Brockbank, study co-author and CEO of Tissue Testing Technologies LLC, estimates nanowarming technology could be ready to use by medical professionals in as soon as 10 years' time. Brockbank is confident this method could be perfected in the next decade and open the way for cryopreserved organ banks.
Since transplant organs have a very narrow time frame of use and must arrive to the recipients within 48 hours after being harvested, more than 60 percent of donor hearts and lungs fail to make it in time to the patients and end up being discarded. The new technology could greatly extend the life of harvested organs and ensure they are available for transplant for a much larger period of time.
How Nanowarming Technology Works
Vitrification requires the use of certain cryoprotectant chemicals that allow the cooling of biological tissues at very low temperatures — between minus 160 and minus 196 degrees Celsius (or minus 256 and minus 320 degrees Fahrenheit). These chemicals are a crucial component in preserving donor tissues and organs in a vitrified state.
Nevertheless, until now, the rewarming process had major faults, typically resulting in the formation of ice crystals that damaged the tissues and made them unfit for use. According to John Bischof, senior study author and engineering professor at UMN, vitrified samples must be reheated in a uniform way and with optimal heath distribution, so as not to "crack the organ."
Bischof and Brockbank devised and ingenious warming method that employs highly magnetic iron oxide nanoparticles to create heath and unfreeze biological samples. These particles were coated with stabilizing chemicals to prevent them from clustering in the cryoprotectant solution.
After establishing the optimal concentration of nanoparticles, the scientists placed them in a magnetic field, where they generated induced heat within the preserved tissues. Further investigation into nanoparticle deployment and balance lead to perfecting the system for larger organs, by eliminating the negative effect of eddy currents and ensuring the tissues were warmed evenly.
Tremendous Benefits In Kidney Transplantation
The nanowarming technology could have important applications in organ banking, radically improving the preservation and distribution of transplant organs.
Thousands of patients are currently on the kidney transplant waiting list and sometimes it takes up to five years to find a compatible match. Since a living donor is difficult to find in most cases, Dr. Anthony J. Bleyer, a nephrologist and professor at Wake Forest School of Medicine, stresses the importance of obtaining kidneys from deceased donor.
Once a kidney is harvested, it's imperative to be transplanted almost immediately, within 24 to 48 hours.
"Sometimes, the time just runs out. It cannot be gotten to the recipient on time," says Bleyer. As a result, the possibility of using cryopreserved kidneys would greatly enhance the patients' chances of receiving a transplant.
Nanowarming could also be used to help patients with inherited kidney diseases, who experience simultaneous gradual deterioration of both kidneys.
"It would be great if we could take one of the kidneys when someone is 10 or 11 years old and cryopreserve it and then wait until the other kidney failed and retransplant that cryopreserved kidney," explains Bleyer.
Could Nanowarming Help Preserve An Entire Human Body?
Nanowarming indubitably expands the horizon of organ cryopreservation, and the future possible applications of this technology are endless. Scientists agree it opens a wide range of unique opportunities, which may even include the bold attempt to preserve an entire human body.
According to Bischof, it is fair to assume that "once you have done a whole organ, there is a certain intellectual connecting of the dots that takes you from the organ to the whole person."
Nonetheless, he doesn't concede that bringing a frozen body back to life will be attainable in the near future, while Brockbank estimates it will take more than 100 years to reach a notable progress in the field of cryonics.
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