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.
Enkephalin Metabolism In Cardiac Ischemia, Heart Failure And Cardiac Surgery
Funder
National Health and Medical Research Council
Funding Amount
$327,037.00
Summary
It has recently been discovered in animal studies that heart muscle can make its own opioid proteins. Previously, it was thought that only nerves made and released opioids. We have recently found that a class of opioids called enkephalins are made and then depleted from the heart during the stress of oxygen and nutrient deprivation. Enkephalins have been found to have potent metabolic effects on the heart. Previous work has shown that opioids can protect the heart against injury incurred during ....It has recently been discovered in animal studies that heart muscle can make its own opioid proteins. Previously, it was thought that only nerves made and released opioids. We have recently found that a class of opioids called enkephalins are made and then depleted from the heart during the stress of oxygen and nutrient deprivation. Enkephalins have been found to have potent metabolic effects on the heart. Previous work has shown that opioids can protect the heart against injury incurred during disease that restricts energy and oxygen supply to the blood vessels and heart. We wish to demonstrate this for the first time in human heart, and we will explore whether the production of enkephalins is altered by the stresses of cardiac surgery and heart failure. Understanding how the human heart attempts to protect itself in disease and how enkephalins work under these conditions, may prove valuable in the development of new drug therapy with synthetic drugs which mimic the action of enkephalins for heart protection during cardiac surgery, heart transplantation and ischemic heart disease. We will test whether specific enkephalins may be used to improve donor heart viability for transplantation by improving the duration and quality of preservation during storage. Understanding what happens to enkephalin production and metabolism in the failing hearts of patients may allow us to find new therapeutic targets in heart failure.Read moreRead less
Optimizing Implanted Cell Survival Using A Tissue Engineering Model
Funder
National Health and Medical Research Council
Funding Amount
$589,175.00
Summary
Cell therapy and tissue engineering involve the insertion of specific cells into damaged tissues or into a bioraector in a patient's body to generate new replacement tissues. This project seeks to improve two factors associated with inserting cells : 1. The innate survival characteristics of the cells being inserted, and 2. The blood vessel supply at the site of insertion. These techniques will greatly improve the survival of inserted cells.
Optimising Islet Transplantation With Vascularized Tissue Engineering Chambers
Funder
National Health and Medical Research Council
Funding Amount
$451,651.00
Summary
Diabetics have high blood sugar levels because cells in the pancreas known as islets produce too little of the hormone insulin. Most diabetics need daily insulin injections to maintain normal blood sugar levels. Transplanting islets is the most promising way to treat type 1 diabetes, but, apart from the obvious difficulty of rejection of foreign islets, several major problems remain: (1) there are insufficient pancreata (and therefore islets) for transplantation; and (2) the efficiency of delive ....Diabetics have high blood sugar levels because cells in the pancreas known as islets produce too little of the hormone insulin. Most diabetics need daily insulin injections to maintain normal blood sugar levels. Transplanting islets is the most promising way to treat type 1 diabetes, but, apart from the obvious difficulty of rejection of foreign islets, several major problems remain: (1) there are insufficient pancreata (and therefore islets) for transplantation; and (2) the efficiency of delivery of surviving islet transplants is too low. In pilot studies we have grown a new living pancreatic organ in mice by inserting islets from genetically-related mice together with a structural protein matrix, growth factors and blood vessels inside a plastic chamber. The blood vessels maintain nutrition to the islet cells and simultaneously allow insulin to be released into the bloodstream, thus normalising the high blood sugar in diabetics. In Aim 1 of these experiments we will find the optimal way to grow mature islets in blood vessel-containing chambers in diabetic mice, focusing on (a) the best time to add islets to the chamber - 0, 1 or 2 weeks after establishment, (b) the minimum number of islets to effectively normalise blood sugar and (c) how long we can keep islets alive and functional in chambers, examining periods up to 12 months. In Aim 2 we will test the ability of islet stem cells (provided by our co-investigators at Walter and Eliza Hall Institute, Melbourne) to survive in the chambers and to produce sufficient insulin to effectively lower blood sugar levels to normal in diabetic mice. In Aim 3 we will grow human islets in chambers in special diabetic mice that do not reject foreign tissue, in order to confirm similar behaviour of human islets in this controlled environment. Using this data, we hope to create a research model of functioning islets, that is accessible, retrievable and manipulable, for the further study of diabetes and transplantation.Read moreRead less
Outcomes Of The Arterial Switch Operation: A Multi-centre Study
Funder
National Health and Medical Research Council
Funding Amount
$86,733.00
Summary
The arterial switch operation is the surgery of choice for children born with transposition of the great arteries, a congenital heart defect where the main two vessels of the heart arise from wrong pumping chambers of the heart. There are very few studies looking at adults after this operation. We aim to study all patients who have had an arterial switch. The results of this study will further increase our knowledge of the long term consequences of having the arterial switch operation.
Preconditioning: The Molecular Basis For Protection From Hepatic Ischemia-reperfusion Injury
Funder
National Health and Medical Research Council
Funding Amount
$406,980.00
Summary
When the blood supply to the liver is cut off temporarily (ischemia) and later restored (reperfusion) the liver is damaged by a process called ischemia-reperfusion (IR) injury. This is a major problem during liver surgery and is also an underlying problem in liver transplantation; following storage of a donor liver ready for placing into the recipient it can undergo a similar process called preservation injury. We now understand a lot about how IR comes about, particularly by the formation of da ....When the blood supply to the liver is cut off temporarily (ischemia) and later restored (reperfusion) the liver is damaged by a process called ischemia-reperfusion (IR) injury. This is a major problem during liver surgery and is also an underlying problem in liver transplantation; following storage of a donor liver ready for placing into the recipient it can undergo a similar process called preservation injury. We now understand a lot about how IR comes about, particularly by the formation of damaging oxygen radicals within liver cells to start a process of programmed cell death, but it remains difficult to prevent or treat IR injury. A recent breakthrough has been recognition that subjecting the liver to only a short period (5 or 10 minutes) of ischemia protects against a later period of prolonged ischemia or IR. In the investigator s mouse model, for example, such preconditioning was 60 to 90% protective (depending on the time after IR). This project seeks to understand how preconditioning works to protect the liver against IR injury. Our idea is that preconditioning generates a limited amount of oxygen radicals, and that these turn on signalling pathways in the cell that regulate certain protective genes. Genes that encode antioxidant and other anti-stress pathways are likely to be important, but so are genes that prepare the cell to enter the cell cycle and divide into new cells that regenerate the liver. Conversely, genes that program cell death may be turned off. The outcomes of this research will be to understand the molecular and cellular basis of how preconditioning protects against ischemia-reperfusion injury of the liver. This will allow drug treatments to be devised that, by simulating preconditioning, prevent this common and severe type of liver damage.Read moreRead less
Randomised Controlled Trials Of Laparoscopic Techniques For Antireflux Surgery
Funder
National Health and Medical Research Council
Funding Amount
$1,031,381.00
Summary
Gastro-oesophageal reflux is common, with approximately 10% of Australians now using medication to control symptoms. Many Australians will need this medication for life, unless they undergo surgery. The cost of treating reflux is growing. Since 1992 the annual growth rate of the Pharmaceutical Benefits Scheme expenditure on reflux medication has been 13%, and the annual cost for the treatment of reflux now exceeds $1 billion. Not all patients with reflux are satisfied with medication, as some co ....Gastro-oesophageal reflux is common, with approximately 10% of Australians now using medication to control symptoms. Many Australians will need this medication for life, unless they undergo surgery. The cost of treating reflux is growing. Since 1992 the annual growth rate of the Pharmaceutical Benefits Scheme expenditure on reflux medication has been 13%, and the annual cost for the treatment of reflux now exceeds $1 billion. Not all patients with reflux are satisfied with medication, as some continue to experience symptoms. Surgery is the only treatment which will cure reflux. It has a clear role in the treatment of patients with ongoing symptoms, those who don t want to take tablets, and patients with a large hiatus hernia in whom symptoms occur due to the relocation of the stomach from the abdomen into the chest. Approximately 5,000 Australians per year undergo surgery for reflux. The standard operation achieves a good outcome in approximately 90%, although some patients are troubled by side effects. To reduce the risk of this, the original procedure has been modified. However, the evidence supporting modifications has until recently been limited. The best way to compare different operations is in randomised trials. The majority of the largest and best trials addressing this area have been undertaken in Adelaide. We have already entered 504 patients into 5 randomised trials, 4 conducted entirely in Adelaide, and one across multiple sites with the cooperation of 15 Australasian surgeons. These trials have provided a more reliable evidence base for surgeons undertaking surgery for reflux. However, long term follow-up is required to ensure that conclusions drawn are valid at late follow-up. In addition we are establishing 2 new randomised trials, which will determine how best to perform surgery for reflux, and how best to repair a large hiatus hernia. These studies will be undertaken in collaboration with more than 25 other surgeons throughout Australia.Read moreRead less
Activin A And Follistatin Are Potential Key Regulators Of Organ Transplant Dysfunction And Graft Survival.
Funder
National Health and Medical Research Council
Funding Amount
$535,579.00
Summary
The grant examines novel key regulators in organ transplantation. It examines molecules that are released during transplant surgery and on the return of blood flow to the organ which can cause inflammation and scarring. The release is increased by heparin, an anticoagulant used in organ preparation. Alternative anticoagulants and blockers of the regulators released will be tested to prevent the damage to the transplant, potentially improving both the short and long term graft survival and functi ....The grant examines novel key regulators in organ transplantation. It examines molecules that are released during transplant surgery and on the return of blood flow to the organ which can cause inflammation and scarring. The release is increased by heparin, an anticoagulant used in organ preparation. Alternative anticoagulants and blockers of the regulators released will be tested to prevent the damage to the transplant, potentially improving both the short and long term graft survival and function.Read moreRead less