- A new machine models the human body, allowing livers to survive for a week.
- Logistics, patient health, and surgery times all squeeze donor livers, making transplants a race.
- Almost all the major organs are involved in keeping the nutrient-greedy liver going in the body.
New Atlas reports that scientists have a new way to keep livers alive for a week—and maybe to bring unfit livers back to life. The solution is a machine that mimics human body functions, which lets the liver continue to work like usual.
Scientists hope this machine can extend viability for all livers and model a solution for other organs. More importantly, the machine can let livers restore themselves to health after damaging car crashes and other injuries that would take the organs of the running for transplant.
The team of researchers responsible for the liver machine, all based in institutions in Zurich, has been building it since 2015. Existing, approved technology for livers keeps them alive for up to 24 hours, and supercooling has extended that to 27 hours, the team explains in its paper. Indeed, an increase of 12.5 percent is huge in the world of organ transplants, where organs must be harvested, transported, and implanted during potentially long surgeries.
The existing technology works through perfusion, which is keeping the liver’s blood vessels open and active with a circulation of body-temperature blood or oxygenated blood replacement-type fluid. The Zurich team saw an opportunity to take simple perfusion and turn it into something more robust “by engineering a perfusion machine that [mimics] additional core body functions that are critical to liver health.”
By choosing a goal of one week, the team aimed to give livers enough time to self repair and regenerate from damage, whether in the form of a traumatic injury in a deceased donor or a patient whose liver is being partly reduced or resectioned because of illness or other damage.
The scientists' system of artificial organs comprising a complete liver-rejuvenating system includes what you’d guess: heart, pancreas, lung, kidneys, and bowels are modeled with things like oxygen pumps and added nutrients. There are also surprises, like basically a whoopie cushion that inflates and deflates to mimic how the diaphragm keeps the liver muscle itself exercised and stimulated inside our bodies. The team found this regular motion is part of what prevents necrosis in the liver.
When a liver is injured, there are chemical and physiological markers. In this research, the scientists wanted to quantify how injured livers improved during the weeklong perfusion period, so they measured markers called DAMPs. The NIH explains what DAMPs are: “Damage-associated molecular patterns are endogenous danger molecules that are released from damaged or dying cells and activate the innate immune system.”
Indeed, even if the liver could repair itself over time, the immune reaction triggered by DAMPs could be much more dangerous in a transplant recipient. The Zurich team received 10 livers that were too damaged to be transplanted and placed them in the perfusion setup.
“We found that six of the livers, which we numbered 1 to 6, demonstrated a decrease in injury and inflammation markers and DAMPS. [...] Livers 1 to 6 were maintained viable for the targeted time period of 1 week, while livers 7 to 10 failed to reach this objective, showing ongoing cell death and signs of liver failure.”
The livers that survived and bounced back had different kinds of injuries and damage, the team concluded. In application, this could mean injured livers all spend a few days in a perfusion system—like life support during a time when they can potentially recover. The livers that don’t recover will have things in common that help scientists better screen livers and improve perfusion going forward. Even a larger group of rejected livers with more consistent age grouping and other factors would help the Zurich team take the next step with its research.
This kind of technology is so exciting, but it’s also extremely far removed from use in real patients. Having a working prototype and preliminary study results, however, is a big step. The improvement from 24 to 27 hours made a 12.5 percent difference and a big impact; a 600 percent improvement is certainly worth looking into.
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