Multi-modal assessment of liver grafts undergoing normothermic machine perfusion to stratify quality and deliver therapy

肝移植是终末期肝病患者的根治性治疗方法，但全球供体器官短缺意味着许多患者在等待合适的肝脏时死去。为了解决这一问题，通常考虑的是来自合并症增加的老年供者的肝脏和循环死亡后捐赠的肝脏。由于对功能和外观的担忧，这些肝脏中的许多都被拒绝移植。关键的决定是基于稀有的功能数据，即捐献时间和检索外科医生判断的主观外观。常温灌流技术现在越来越多地应用于临床实践，似乎可以提高器官移植的利用率，并提供更好的临床结果。肝脏的常温灌流在体外维持器官的功能状态，并在正常体温下提供氧气和营养物质长达一周。这使得对器官功能的动态评估增加了外科医生使用器官的信心。目前这项评估是基于有限的生化参数。器官的常温灌流提供了几个尚未在临床环境中开发的额外机会，包括深入评估肝脏的质量和功能，直接向肝脏提供新的治疗方法，以及评估这些治疗方法如何影响器官的质量和功能。我们希望通过灌流从自愿捐赠者那里获取的用于移植的人体器官来探索其中的一些机会。首先，我们希望结合成像方式(如拉曼光谱或多路多传感光纤)和使用蛋白质组学、游离DNA、单细胞测序等技术分析肝脏的代谢功能，对肝脏进行实时评估。这将使我们能够了解脑死亡(DBD)和循环死亡(DCD)如何影响肝脏及其各种细胞的差异，并开发潜在的治疗方法来靶向和修复这些负面影响。第二，我们希望将细胞治疗直接输送到肝脏，同时保持在机器上的生命。我们会集中研究计划第一部分所确定的改善肝脏质素的治疗方法，并从不适宜人类移植的肝脏中分离细胞，以尽量利用器官。我们会利用计划第一阶段发展的多模式评估策略，评估这些治疗方法在改善肝脏质素方面的成效。如果器官被移植，我们会使用机器学习和信息学来分析从这些化验所得的数据，并与移植后的临床结果相关。如果临床医生发现这些器官不合适，并且有近亲同意使用这些器官进行研究，我们将从这些肝脏中分离出细胞用于治疗。这项拟议的研究将产生新的临床相关生物标志物，并开发新的实时技术来深入评估肝移植的质量和任何介入治疗的效果。这将产生重大的临床影响，从而提高器官利用率，并将器官丢弃降至最低。其次，建立肝源性细胞疗法的概念，并在机器灌流期间提供针对器官的治疗，将使所有捐赠的器官得到利用，并使器官修复中心得以发展，在那里可以在适当的环境中提供这种治疗，并使用开发的多模式评估工具评估其效果。

Liver transplantation is a curative treatment for patients with end stage liver disease but a global shortage of donor organs means that many patients die waiting for suitable liver. To address this, livers from older donors with increasing comorbidity and livers donated after circulatory death areroutinely considered. Many of these livers are turned down for transplantation due to concerns about function and appearance. The critical decisions are based on scarce functional data availableat the time of donation and subjective appearance as judged by the retrieving surgeons.Normothermic perfusion technology is now increasingly used in clinical practice and appears to improve the utilisation of organs for transplantation and provide better clinical outcomes. Normothermic perfusion of the liver maintains the organ in a functional state outside the body and delivers oxygen and nutrients at normal body temperature for up to a week. This allows a dynamic assessment of the function of the organ increasing surgeons' confidence to use the organ. At present this assessment is based on limited biochemical parameters.Normothermic perfusion of the organs offer several additional opportunities which are yet to be developed in the clinical setting, which include an in-depth assessment of liver quality and function, delivery of new therapies directly into the liver and evaluation of how these therapies affect the quality and function of the organ. We want to explore some of these opportunities by perfusing human organs retrieved for the purpose of transplantation from consenting donors.In the first instance, we want to assess the liver in real time combining imaging modalities (such as Raman spectroscopy or multiplex multi-sensing fiber optics) with analysis of the metabolic function of the liver using technologies such as proteinomics, cell free DNA, single cell sequencing. This will allow us to understand the difference in how brain death (DBD) and circulatory death (DCD) affect the livers and its various cells and develop potential therapies to target and repair these negative effects.Secondly, we want to deliver cell therapies directly into the liver whilst kept alive on the machine. We will focus on therapies directed at improving the quality of the liver as identified in the first part of the project and isolate the cells for these therapies from livers that are unsuitable for human transplantation to maximise organ utilisation.Using the multi-modal assessment strategies developed in the first stage of the project we will evaluate how effective these therapies are in improving the quality of the liver.If the organs are transplanted, we will use machine learning and informatics to analyse data generated from these assays and correlate with the clinical outcome post transplant. If the organs are found unsuitable by clinicians and there is the next of kin has consented to use these organs for research, we will isolate the cells from these liver to use as therapies.This proposed research will generate novel clinically relevant biomarkers and develop new real time technology to assess in depth the quality of the liver grafts and the effect of any interventional therapy. This will have a significant clinical impact allowing an increase in organ utilisation and minimise organ discard. Secondly, establishing the concept of liver derived cell therapies and delivery of therapies targeted to the organ during machine perfusion, will allow the utilisation of all donated organs and enable the development of organ repair centres where such therapies can be delivered in appropriate environments and their effects assessed using the multi-modal assessment tools developed.