Autologous Macrophage Therapy for Liver Cirrhosis

Liver cirrhosis is a common disease that is due to many causes including viral hepatitis, obesity, alcohol abuse, genetic liver disease, and immune system dysfunction. Regardless of the cause of the liver injury advanced liver cirrhosis results eventually in liver failure and death. The incidence of deaths from liver cirrhosis is rising rapidly in the UK. The only successful treatment for end stage liver disease is liver transplantation but this has several problems in addition to the risk from the operation itself: Organ supply is limited and patients unfortunately frequently succumb on the liver transplant waiting list before a suitable organ becomes available. Other problems with transplantation are that immunosuppression increases the risk of renal failure, cancer and severe infections. The severity of liver cirrhosis can be measured using simple numerical scores such as the MELD and UKELD scores. These scores predict the future risk of death from liver cirrhosis and are used to assess and prioritise a patients need for liver transplantation.

The normal liver as an incredible capacity to regenerate following short term damage and can accomplish this efficiently through division of the cells in he liver such as hepatocytes ad biliary epithelial cells. A hallmark of cirrhosis is that here is an increased deposition of scar tissue in the liver and this combines with other factors to reduce the livers ability to regenerate. Our research over several years has shown that if the injurious insult to the liver is removed, for example by treating a viral infection or inflammatory condition then the liver can regenerate to a degree. This recovery phase is coordinated ad achieved in large part through the action of cells termed macrophages. We have shown that when the chronically damaged liver is undergoing repair and regeneration the macropahges are important for reducing the scar tissue in the liver, stimulating the livers own stem cells to expand and multiply and finally help those stem cells turn into hepatocytes through the secretion of several factors.

We have exploited these features of the macrophage to develop a cell therapy for liver cirrhosis that we would like to take forward for a clinical trial in man for the first time. We have shown in mouse model of liver fibrosis that the injection of macrophages, grown in the lab from bone marrow, is able to reduce significantly the scarring and improve regeneration and liver function. We have gone on to perform studies with human cells isolated from healthy volunteers and patients with liver cirrhosis. Here we can isolate large amounts of monocytes from patients blood and turn them into macrophages that have similar properties to the mouse cells over a 1 week period. We have tested these cells in models of liver injury and they also reduce fibrosis and increase liver regeneration.

In this grant we are seeking to turn these encouraging results into a treatment for patients with cirrhosis. Cirrhotic patients will have monocytes isolated using a cell separator machine which takes 2 to 4 hours. The monocytes will be split into 3 parts which will be frozen for later use. As required the frozen monocytes will be defrosted and differentiated into macrophages. The macrophages will be re-infused under close monitoring in 3 groups of 3 patients using increasing cell numbers up to 100 million cells. If this single dose is well tolerated we will perform, in 15 separate patients a repeat infusion study. in this study patients will receive 3 macrophage infusions of cells at 8, 30 and 60 days post monocyte isolation. Patients will be observed regularly for up to 1 year with regular blood test, ultrasound scans and a type of MRI scan that will tells us how well the liver is functioning. If this first in man study is successful and we would plan to extend to a randomized study which we would plan to conduct across other sites in the UK.

The only curative option for end-stage cirrhosis is liver transplantation but donor organ availability cannot meet demand and many patients die waiting for a suitable organ. Our work has helped to define the role of macrophages in the reversal of liver fibrosis. In rodent models of liver injury and fibrosis bone marrow derived macrophages (BMDMs) induced regression of scarring and stimulated liver regeneration. BMDM injection increased hepatic matrix metalloproteinases, increased IL-10 and reduced hepatic fibrosis. BMDM injection activated hepatic progenitor cells (HPCs), improved liver regeneration and liver function. BMDMs secreted tumour necrosis factor-like weak inducer of apoptosis (TWEAK) which induces HPC expansion and Wnt, which differentiates HPCs into hepatocytes.
Our study group are patients with cirrhosis, below the listing threshold for liver transplantation (MELD score <15, UKELD <50). In this group small changes in liver function have a major impact on survival and morbidity. We will conduct a first in human study of repeated autologous CD14+ monocyte derived macrophage (MDM) therapy for liver cirrhosis with the aim of reducing liver scarring and promoting liver regeneration. We have found that cirrhotic patients can tolerate the clinical leukapheresis procedure as well as healthy controls and yield high numbers of CD14+ monocytes (typically 109 per leukapheresis). We have developed a GMP compatible protocol to differentiate CD14+ monocytes into mature monocyte derived mature macrophages (MDMs). These human MDMs have a similar gene, surface and functional profile as the regenerative mouse BMDMs. In an immunodeficient mouse model of chronic liver injury MDMs reduced inflammation and scarring and stimulated regeneration. The study will involve a cell dose escalation study, followed by a repeat cell administration study. Measured outcomes will include serum markers of liver function and fibrosis and 31P-Magnetic Resonance Spectroscopy.

Liver disease is the 5th commonest cause of death in the UK and the deaths from cirrhosis are rapidly rising (British Liver Trust, www. britishlivertrust.org.uk ). 16,087 people in the UK died from liver disease in 20082, a 4.5% increase since 2007. In England the number of people who died from liver disease rose from 9,231 in 2001 to 11,575 in 2009 (Office of National Statistics, www.statistics.gov.uk). Most liver deaths were in people under 70, while one in 10 deaths of all people in their 40s were from liver conditions. Deaths from CLD now account for 1 in 50 of all Scottish deaths (Health in Scotland 2007: Annual Report of the Chief Medical Officer). These rising rates also contrast with falling mortality rates in recent years from the top 3 causes of mortality in Scotland: Coronary Heart Disease, Cerebrovascular Disease and Cancer (Overview of Scotland's Health and NHS Performance Audit Scotland 2007 http://www.audit-scotland.gov.uk/docs/health/2007/nr_071214_nhs_overview.pdf ).

The only curative option for end-stage liver disease is liver transplantation but donor organ availability cannot meet current demand and many patients die whilst waiting for a suitable organ. At time of writing there are 465 adults awaiting a liver transplant around the UK, and 41 patients in Edinburgh which serves the whole of Scotland. Unfortunately due to the limited supply of donor organs a significant proportion of these patients will die whilst waiting for a liver transplantation (http://www.organdonation.nhs.uk/statistics). Furthermore many patients with end stage liver disease are not eligible for transplantation. Those who do receive transplantation require lifelong immunosuppression with the increase health risks this involves. Our study is specifically targeted to patients who have cirrhosis but are just below the threshold for listing for liver transplantation (MELD score <15, UKELD<50). This group of patients are suitable for study as small changes in liver function will have a major impact on both their survival and morbidity such as recurrent hospital admissions. Patients with advanced cirrhosis have many episodes of decompensation with frequent episodes to hospital and intensive care. Shawcross et al recently estimated the cost of an ITU admission for a cirrhotic patient at Euros 14,000 ( Shawcross D et al. J Hepatol. 2012 May;56(5):1054-62.) Impacting on the level of liver dysfunction in this common group of patients and thereby reducing the frequency of costly hospital and high dependency/intensive care admissions would therefore be expected to have major positive health economics impact.

If the phase 1 study described here were successful and passed the milestones described we would plan to develop this as a phase 2 randomised study with the input of the Cell Therapy CATAPULT (https://ct.catapult.org.uk/), who's aims include "Taking products into clinical trial, de-risking them for further investment". Any intellectual property arising during this program would be appropriately protected with the input of the University and partners (Scottish National Blood Transfusion). Furthermore, the University of Edinburgh has a strong record of exploiting innovative research findings through commercialisation of intellectual property (led through Edinburgh BioQuarter). To maximise the scientific and clinical impact from this regenerative medicine the investigators will closely involve the developing regenerative network provided by the UKRMP hubs of which Forbes is a director of the Niche Hub. The investigators have a record of publishing in high impact journals with wide readership in the relevant scientific and clinical communities. The MRC Centre for Regenerative Medicine has a strong outreach program which will help disseminate results to appropriate patient groups and stakeholders.