Abundance of Life Saving Donated Organs in the Future? It’s Possible.
Every year, thousands of donated organs go to waste because they cannot be matched with recipients in the brief window of time in which they are still viable. Right now, 22 people die in the US each day on average while waiting for an organ transplant.”If only half of these discarded organs were transplanted, then it has been estimated that wait lists for these organs could be extinguished within two to three years,” the researchers, led by John Bischof from the University of Minnesota, write in Science Translational Medicine.
A better solution could be cryopreservation – keeping tissue stored at temperatures around -80 to -190 degrees Celsius (-112 to -310 degrees Fahrenheit). One of the leading cryopreservation techniques is vitrification – which involves super-cooling biological samples to a glassy state at around -160 degrees Celsius (-256 degrees Fahrenheit). In fact, vitrification is already being used on human brains by cryonics companies.
But while they’ve managed to get the cooling part down, the problem is that the thawing process can cause ice crystals to form and damage tissue, and potentially even crack it during the thawing process.
In the past, researchers have successfully shown that thawing can work in small tissue samples up to around 1 mL in volume. But as tissue gets larger, and approaches the size of entire human organs, the current leading technique of convection – slow warming over ice – doesn’t work.
That could be about to change, with the Minnesota team announcing the development of a new technique that has allowed them to rapidly rewarm cryogenically treated human and pig samples without damaging delicate frozen tissues.
“This is the first time that anyone has been able to scale up to a larger biological system and demonstrate successful, fast, and uniform warming of hundreds of degrees Celsius per minute of preserved tissue without damaging the tissue,” said Bischof. Instead of using convection, the team used nanoparticles to heat tissues at the same rate all at once, which means ice crystals can’t form, so they don’t get damaged.
The team admits that larger tissue – and even whole organs – will need to have the nanoparticles injected into them, rather than just sitting around them, to achieve the same uniform heating, but it’s something they want to try next. It’s important to note that the team hasn’t successfully shown that their technique actually works on organs, which are made up of complex arrangements of multiple tissue types.
That’s something that will require a lot of optimisation and tweaking, so we’re a long way off being able to bring organs back from cryopreservation. But it’s the first time we’ve seen such large volumes of tissue successfully be thawed from a cryopreserved state, and that’s pretty exciting.