Scientific American May 2020 pp10-12. Advances Medical Tech “Staying Alive” “A new machine preserves livers for a week outside the human body”
Currently donor livers are flushed with cold water and iced remaining viable for only about 12-18 hours. About 40% of all livers are damaged due to excessive fat, damaged by a donor’s disease process or they are too old to transplant.
A Swiss group reported in “Nature Biotechnology” that they have successfully preserved and successfully transplanted pig livers as old as one week. This has been enabled by a device that mimics “key features of the human body”. The livers are perfused with blood under carefully controlled pressure, oxygen, glucose and electrolyte concentrations. Insulin and glucagon, that regulate glucose levels by decreasing and increasing glucose levels respectively, are injected to optimize glucose levels and a dialysis unit maintains electrolyte levels and removes toxic waste products. Physical pressure on the donor liver is reduced by mimicking the movement of the diaphragm.
Human livers, too damaged for transplant, were tested using the Swiss device and six of the ten livers showed lower levels in damage-associated-molecular-patterns (DAMP). Other signs were reduced as well. Although the data are scant, there is hope that the device will actually revitalize marginal donor-livers to enable successful transplantation. While a hope of transplant researchers, it remains to be fully vetted that liver regeneration can be achieved outside of the body, or In Vitro, with this device. Such a technological leap would make more livers available for recipients and even allow patients with damaged livers to remove, regenerate and replace-autologous donor organs are not subjected to immune-mediated rejection or graft versus host disease.
Next steps. If the pig-liver studies show long-term in body, or In Vivo, viability then similar studies will begin in larger animals. With further success, patients unlikely to get a liver-those with lower priority would be candidates for first-in-human clinical trials for livers sustained by this new method. Hopes are high that such studies could be happening this year. Others are looking to extend studies to other organs.
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