Nature subjournal: a major breakthrough! The new technology enables the liver to realize "7-day extra long standby" in vitro!

Author: Wang Fang's liver transplantation is the most effective way to survive in the desperate situation of patients with advanced liver cancer However, due to the limited number of donors and the limitation of organ preservation technology, only a few patients receive liver transplantation every year A new report published in Nature Biotechnology shows that this dilemma is expected to be solved through a new technology The report comes from a team of surgeons, biologists and engineers at the University of Zurich who have developed a perfusion technique that can not only preserve the metabolically active liver for one week in vitro, but also repair the damaged liver and restore its function Https://doi.org/10.1038/s41587-019-0374-x generally speaking, the preservation of donor liver is to wash the organ with cold solution during extraction, and then store it statically on ice at the cost of reducing metabolic activity, and the liver can only be preserved for 12-18 hours In contrast, the way of machine perfusion can maintain the complete metabolic activity of the liver in the controlled environment for up to 24 hours, but it will take longer to repair the liver Therefore, in this experiment, the researchers set the liver preservation time to 7 days Early experiments on pig liver showed that in order to make the perfusion liquid achieve the ability of long-term preservation of liver, we must remove five obstacles: control glucose metabolism, prevent hemolysis, remove waste, control perfusion liquid oxygenation and diaphragm simulation movement In this experiment, the researchers study and overcome these problems one by one The specific methods are as follows: · using continuous on-line sensors to automatically monitor the glucose level in the perfusion fluid, and realizing the closed-loop control of glucose level by automatically injecting insulin and glucagon; · selecting the perfusion circuit with only one pump head and one oxygenator to generate the pulse blood flow, thus forming a pulse waveform imitating the internal environment; ·In the perfusion circuit, the dialysis membrane is integrated to perform the key renal excretion function, so that the perfusion fluid does not need to be changed within 7 days; · an algorithm that can automatically adjust the blood oxygen saturation of the portal vein is used to maintain the physiological flow of the hepatic artery while avoiding the excessive oxygenation of the portal vein; · the diaphragm movement of the liver is induced by the way of artificial maintenance of pulmonary ventilation After seven days of machine perfusion, the researchers tested the viability of these livers and found that they did not differ in function from the standard cold transplanted livers The researchers then tested the new technology using 10 human livers discarded by hospitals Previously, these human livers were rejected by all European hospitals due to their poor function The livers were connected to the perfusion machine in vitro by hepatic artery, portal vein, vena cava and bile duct The researchers observed that six livers survived for 7 days and recovered their original functions In addition, their previous injuries were also repaired Although more tests are needed to evaluate the actual effect of machine perfusion, the new technology suggests that those livers that do not meet the requirements of transplantation may also be used to save patients' lives after purification and repair At the same time, it is expected to divide the donor liver into several anatomical segments and regenerate in the machine in the future, so as to double or even triple the availability of transplanted organs Reference: [1] an integrated perfusion machinereserves adjusted human lives for 1 week