Significance Of Microparticles In The Pathogenesis Of Liver Ischemia Reperfusion Injury
Funder
National Health and Medical Research Council
Funding Amount
$643,958.00
Summary
The overall aim of the project is to investigate the significance of microparticles in liver ischemia reperfusion injury (IRI). IRI causes damage to donor livers stored in preparation for liver transplantation. We postulate that microparticles released from the liver are critical in this form of injury. The expected outcomes are novel insights into liver IRI with the aim of developing new approaches to prevent liver damage during liver surgery, transplantation and shock.
Basic Mechanism Of Spontaneous Tolerance Of Liver Allografts In A Rat Model.
Funder
National Health and Medical Research Council
Funding Amount
$374,625.00
Summary
Many thousands of Australians have a failing liver and the only treatment for this is a liver transplant. Liver transplantation is a major life-saving strategy and hundreds of Australians are rescued each year who would otherwise have died. Rejection of the transplant is the major problem affecting these patients. This project investigates an animal model where a transplanted rat liver is not rejected, even though the recipient receives no treatment. Previous studies from our group have shown th ....Many thousands of Australians have a failing liver and the only treatment for this is a liver transplant. Liver transplantation is a major life-saving strategy and hundreds of Australians are rescued each year who would otherwise have died. Rejection of the transplant is the major problem affecting these patients. This project investigates an animal model where a transplanted rat liver is not rejected, even though the recipient receives no treatment. Previous studies from our group have shown that acceptance is due to donor white blood cells transferred with the liver and based on this finding we are developing treatments that can be used in transplant patients. The current application for funding tests another breakthrough that we have recently made, that treatment of the recipient with a substance called interleukin 4 prevents liver acceptance. This finding shows that interleukin 4, which was previously thought to be involved in preventing transplant rejection, is actually involved in stimulating rejection of the liver. It might therefore be possible to prevent rejection by altering the pattern of its expression, for example, by using an antibody to remove it. This application also aims to examine the overall expression of a very large number of genes in liver transplant acceptance compared with rejection. This will use a new technology called gene array analysis to examine expression of at least 5,000 genes to identify those that are increased during liver acceptance. In addition, gene therapy will be used to increase expression of a single gene called IDO that we and others have found to be associated with transplant acceptance. This gene will be expressed in white blood cells of the liver donor after transplantation to promote liver acceptance and prevent rejection. Ultimately it is intended that these findings will be used to prolong the survival of liver transplant patients by revealing new ways to prevent rejection of liver transplants.Read moreRead less
Unraveling Mechanisms Of Liver Transplant Tolerance
Funder
National Health and Medical Research Council
Funding Amount
$694,822.00
Summary
Liver transplants are unique amongst solid organs as they are spontaneously accepted across different individuals and induce acceptance of other organs from the same donor co-transplanted at the same time. Using a new mouse liver transplantation model, this proposal will elucidate how the liver tissue performs this function and identify new markers associated with tolerance in the blood of mice. This knowledge will be used to identify liver transplant patients with reduced rejection risk.
DEVELOPMENT OF CLINICALLY APPLICABLE STRATEGIES TO INDUCE AND MONITOR LONG TERM ACCEPTANCE OF LIVER ALLOGRAFTS
Funder
National Health and Medical Research Council
Funding Amount
$287,036.00
Summary
Liver transplantation is the only therapy for end-stage liver disease and thousands of Australian lives have been saved with this treatment. The major complication of liver transplantation is rejection which leads to loss of about half of the transplanted livers by ten years. Liver transplants in many animal models are not rejected and function normally for the life of the animal. Using one such animal model we have shown that white cells from the donor are responsible for the absence of rejecti ....Liver transplantation is the only therapy for end-stage liver disease and thousands of Australian lives have been saved with this treatment. The major complication of liver transplantation is rejection which leads to loss of about half of the transplanted livers by ten years. Liver transplants in many animal models are not rejected and function normally for the life of the animal. Using one such animal model we have shown that white cells from the donor are responsible for the absence of rejection. Of interest, these cells appear to stimulate a rapid and extreme immune response, which closely resembles rejection. The main difference is that it is quicker and more marked than rejection and then exhausts itself. This observation is unexpected and suggests possibilities for new treatments. Furthermore it questions the effectiveness of our present treatment for rejection of transplanted livers. We have already shown that some kinds of drugs given to prevent rejection in humans actually have the opposite effect in the animal model and prevent long-term acceptance of liver transplants. The aim of this work is to develop in our animal model a better way of treating human liver transplant patients. This will incorporate injection of donor white cells and treatment with drugs which promote the beneficial effects of these cells. We will also develop ways of testing the blood or the liver of the human liver transplant patients early after transplantation to find out whether the patient is accepting the liver or not. This means that we should be able to try this new treatment method in liver transplant patients once it has been optimised in the animal model.Read moreRead less
Role Of Tryptophan Metabolism In Liver Transplant Tolerance And Rejection
Funder
National Health and Medical Research Council
Funding Amount
$401,203.00
Summary
Many thousands of Australians have a failing liver and the only treatment for this is a liver transplant. Liver transplantation is a major life-saving strategy and hundreds of Australians are rescued each year who would otherwise have died. Rejection of the transplant is the major problem affecting these patients. This project investigates an animal model where a transplanted rat liver is not rejected, even though the recipient receives no treatment. Previous studies from our group have shown th ....Many thousands of Australians have a failing liver and the only treatment for this is a liver transplant. Liver transplantation is a major life-saving strategy and hundreds of Australians are rescued each year who would otherwise have died. Rejection of the transplant is the major problem affecting these patients. This project investigates an animal model where a transplanted rat liver is not rejected, even though the recipient receives no treatment. Previous studies from our group have shown that acceptance is due to donor white blood cells transferred with the liver and based on this finding we are developing treatments that can be used in transplant patients. The current application for funding tests another breakthrough that we have recently made, that treatment of the recipient with a substance called 1-methyltryptophan prevents liver acceptance. 1-methyltryptophan prevents the activity of an enzyme called indoleamine dioxygenase, which we have shown to be increased in liver recipients that accept their graft. This is strong evidence that indoleamine dioxygenase is involved in liver transplant tolerance. These findings show that liver acceptance should be improved by increasing the levels of indoleamine dioxygenase at the time of transplantation. The aim of the current application is to examine whether increased levels of indoleamine dioxygenase expression in the transplanted liver can lead to an improved outcome. We will use two novel techniques to increase expression: gene therapy or treatment of the donor with IL-4. For gene therapy, an expression system will be used that we have recently shown is specific for the liver. In current NHMRC-funded experiments we have shown that IL-4 treatment of donor liver leads to marked increases in indoleamine dioxygenase expression. Ultimately it is intended that these findings will be used to prolong the survival of liver transplant patients by revealing new ways to prevent rejection of liver transplants.Read moreRead less
Does Immunosuppression Affect The Post-transplantation Hepatic Fibrogenic Response?
Funder
National Health and Medical Research Council
Funding Amount
$360,000.00
Summary
Liver transplantation is often the only treatment option for patients who progress to end-stage liver disease after initial treatment has failed. Unfortunately, re-emergence of disease is common and patients often develop fibrosis and cirrhosis (scarring of the liver) in the donor organ. In some cases it has been observed that this scarring often develops rapidly, sometimes in a year or less following transplantation. Re-transplantation is often required. This differs from the usual progression ....Liver transplantation is often the only treatment option for patients who progress to end-stage liver disease after initial treatment has failed. Unfortunately, re-emergence of disease is common and patients often develop fibrosis and cirrhosis (scarring of the liver) in the donor organ. In some cases it has been observed that this scarring often develops rapidly, sometimes in a year or less following transplantation. Re-transplantation is often required. This differs from the usual progression of cirrhosis pre-transplant which often takes years or decades to develop. While essential to prevent rejection of the transplanted organ, immunosuppression is not without side effects. To date, few studies have examined the effect of immunosuppressive agents on the development of hepatic fibrosis and the key fibrosis effector cell type, the hepatic stellate cell. These reports have shown that one of the most commonly used immunosuppressant agents (FK-506) may adversely influence fibrosis progression while rapamycin may prevent fibrosis progression. However little is known regarding the mechanisms through which this occurs. We propose to examine the effect of four different immunosuppressants on fibrosis development both in vitro and in vivo to determine whether scar development or scar breakdown pathways are altered post-immunosuppression. If the factors driving the fibrogenesis in the transplanted organ can be elucidated it may then be possible to develop therapeutic strategies to tackle the problem. This may result in a reduced need for re-transplantation which has obvious benefits to the transplant patient but would also reduce the numbers of donor organs required.Read moreRead less
Protecting Fatty Livers From Hepatic Ischemia-reperfusion Injury In Liver Surgery And Transplantation
Funder
National Health and Medical Research Council
Funding Amount
$624,960.00
Summary
About one third of the population have a fatty liver, and this greatly increases risks of liver failure after liver surgery or when fatty donor livers are used for transplantation (such organs are currently disposed of). The disease process is called ischemia-reperfusion injury (IRI). The investigators have recently shown that both fibrates and statins provide partial protection against IRI in fatty livers. This research is directed at establish the protective mechanisms, and whether combination ....About one third of the population have a fatty liver, and this greatly increases risks of liver failure after liver surgery or when fatty donor livers are used for transplantation (such organs are currently disposed of). The disease process is called ischemia-reperfusion injury (IRI). The investigators have recently shown that both fibrates and statins provide partial protection against IRI in fatty livers. This research is directed at establish the protective mechanisms, and whether combination drugs are more effective.Read moreRead less
Pharmacodynamics In Liver Disease And In Liver Surgery
Funder
National Health and Medical Research Council
Funding Amount
$899,646.00
Summary
The liver is the main organ in the body for drug metabolism and detoxification. This work seeks to address the poorly understood question: what is the in vivo disposition and response in liver of the drugs for treatment of liver diseases? The results of this work will help us better design new drugs and choose the most effective drugs for liver disease. The research may also help us find a better strategy for liver transplantation and thus improve success rates.