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Normothermic machine perfusion found to salvage fatty livers for transplantation



Using normothermic machine perfusion (NMP) to preserve steatotic livers may result in more successful transplantation of these organs, especially when used concomitantly with lipid apheresis filtration and defatting agents, results from a small trial showed.

Dr. Carlo Ceresa is a clinical research fellow with the Medical Research Council and a PhD candidate at the University of Oxford, England. Doug Brunk/MDedge News

Dr. Carlo Ceresa

“This is important in the context of liver transplantation, because fatty livers do very badly when their time is blunted,” study coauthor Carlo Ceresa, MBChB, MRCS, said during a press briefing at the annual meeting of the American Association for the Study of Liver Diseases. “They’re susceptible to ischemia reperfusion injury, and as a result, a large number are discarded. In the U.S., it’s estimated that around 6,000 steatotic livers are discarded each year. In the U.K., the picture is very similar. Because up to 20% of patients die on the waiting list for liver transplant, we need to try to identify methods to use more marginal organs. Unfortunately, with the obesity epidemic and obesity being a risk factor for NAFLD [nonalcoholic fatty liver disease], we find more fatty livers in the donor pool, and we aren’t able to use them. Identifying methods to salvage these livers for transplantation [is] of great importance.”

NMP maintains the liver in a fully functioning state ex situ and provides oxygen and nutrition at 37° C, said Dr. Ceresa, who is a clinical research fellow with the Medical Research Council and a PhD candidate at the University of Oxford, England. In an effort to evaluate the impact of NMP and defatting adjuncts on human steatotic livers, he and his colleagues perfused 18 discarded human steatotic livers on a normothermic, blood-based circuit for 48 hours. Of these, six were perfused by normothermic machine perfusion alone (group 1), while six were perfused by NMP plus apheresis filtration, which removes lipoproteins (group 2). “The hypothesis here was that we could mechanically remove the fat that the liver releases,” he said. The remaining six livers were perfused with NMP, lipid apheresis filtration, and defatting agents including L-carnitine and forskolin (group 3).

The livers in group 1 “did pretty badly,” Dr. Ceresa said. “Their function wasn’t great and within 48 hours deteriorated, and there was a slight increase in liver fat. That’s probably attributable to de novo lipogenesis.” However, the livers in groups 2 and 3 demonstrated a significant reduction in circulating triglycerides and in perfusate total cholesterol by 48 hours, compared with those in group 1. The researchers also observed an increase in median fatty acid oxidation as measured by 3-hydroxybutyrate among the livers in group 3, compared with those in groups 1 and 2. In addition, the livers in group 3 were the only ones to show a mean reduction in tissue triglyceride level.

Dr. Ceresa described the findings as “exciting, because we have a captive organ we can manipulate, which could then result in a successful transplantation,” he said. “You also get to test drive and get an objective assessment of the organ’s function before you transplant it, so the result may be more predictable. It gives us a very useful model to study NAFLD.”

The next step, he said, is to plan a clinical trial to determine if clinical outcomes can be improved through these ex situ interventions on steatotic livers.

Dr. Ceresa reported having no financial disclosures.

Source: Hepatology 2018;68[S1], Abstract 3.

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