Reduced Ischaemic Tolerance In The Aged Myocardium: The Role Of Adenosine And Adenosine Receptors
Funder
National Health and Medical Research Council
Funding Amount
$470,250.00
Summary
Despite a decline in deaths rates due to heart disease over the last decade, cardiovascular disease remains the single greatest cause of premature death in individuals over 65 years of age. It accounts for a major and increasing portion of health care costs. Coronary artery disease affects 50% of those older than 65, and with the ageing of our population it is estimated that the elderly population will nearly double from 13-14% to 25% over the next 30 years. Unfortunately, it appears that the ag ....Despite a decline in deaths rates due to heart disease over the last decade, cardiovascular disease remains the single greatest cause of premature death in individuals over 65 years of age. It accounts for a major and increasing portion of health care costs. Coronary artery disease affects 50% of those older than 65, and with the ageing of our population it is estimated that the elderly population will nearly double from 13-14% to 25% over the next 30 years. Unfortunately, it appears that the aged heart is less resistant to disease and injury, contributing to the increase in mortality with ageing. The reasons are not known. This research project will attempt to identify molecular changes which occur in the heart during ageing which may lead to a decline in ability to withstand disease and injury. The research will specifically examine the possibility that a key protective response, known as the adenosine receptor system, is somehow impaired or abnormal in the cells of the aged heart. If it is found that this process is impaired, the research will attempt to rectify this abnormality using new genetic therapy techniques to switch on the heart's own intrinsic defense mechanisms. This may ultimately open up new avenues for specific therapeutic approaches to treatment of ischaemic heart disease in the elderly.Read moreRead less
The Role Of Aquaporins In Cardiac Ischaemia And Reperfusion
Funder
National Health and Medical Research Council
Funding Amount
$412,670.00
Summary
We are studying the important clinical problem of why the heart doesn't work very well after it has been deprived of blood. This may occur during a heart attack due to coronary artery disease and during cardiac surgery when the heart is stopped. The problem affects children as well as adults undergoing surgery. The reason the heart doesn't work well is related to energy supply and tissue damage caused during the shortage of blood supply and the period soon after flow is restored. Until the heart ....We are studying the important clinical problem of why the heart doesn't work very well after it has been deprived of blood. This may occur during a heart attack due to coronary artery disease and during cardiac surgery when the heart is stopped. The problem affects children as well as adults undergoing surgery. The reason the heart doesn't work well is related to energy supply and tissue damage caused during the shortage of blood supply and the period soon after flow is restored. Until the heart recovers, inadequate pump function may cause low blood flow problems downstream in vital organs such as the brain and kidneys. Under the microscope, a common feature of affected hearts is swelling of the cells and of the energy producing parts called mitochondria. We have identified, for the first time, unique proteins that allow water to move into and around cells of the heart. These proteins are called 'aquaporins' and early results suggest they are involved in how mitochondria deal with a shortage of blood supply. Interestingly, aquaporins are also affected in diseases that affect muscle strength, and we are using what is known in these diseases to further study the role of aquaporins in the heart. Our experiments to will test heart function from the level of the cell, all the way up to the whole heart. To improve the power of our experiments, we are working with mice that lack the special water transport proteins, as a prelude to developing drug therapy for this important problem. By manipulating aquaporin levels or function, we plan to improve heart preservation during periods of no blood flow, and after surgery. This would importantly reduce the risks associated with heart attack and cardiac surgery by avoiding complications associated with poor pump function.Read moreRead less
A Temporal Profile Of Signaling Via Phosphorylation During Myocardial Ischemia - Reperfusion Injury
Funder
National Health and Medical Research Council
Funding Amount
$369,641.00
Summary
Cardiovascular disease (CVD) is the major cause of death in Australians and sequelae post-myocardial ischemia - reperfusion (I-R) are responsible for the greatest proportion of CVD-related mortality. Despite this burden, there is little known of the molecular events that mediate I-R. This project will utilize cutting-edge technology to elucidate the molecular signaling events that lead to I-R injury, as well as determine the basis for protection afforded by clinical pre- and post-conditioning.
Towards A New Normokalemic Arrest Paradigm For Orthotopic Heart Transplantation
Funder
National Health and Medical Research Council
Funding Amount
$489,634.00
Summary
Innovations from Nature to Heart Transplantation:a Real Heart Stopper Heart preservation is limited to 4-6 hours of cold-ischaemic storage (0 to 4 C). The risk of post-transplant death doubles if the donor heart is stored from 1 to 5 hours, and triples with 7 hrs storage times. We have developed a new preservation solution borrowing from natural hibernators that will permit organs to be safely stored for up to 15 hours, and offering new opportunities to organ donors and recipients worldwide.
Delayed Phase Of Remote Ischemic Preconditioning: Clinical Application And The Role Of Kallikrein-kinin Pathway.
Funder
National Health and Medical Research Council
Funding Amount
$159,197.00
Summary
Brief episodes of interruption of blood flow to the arm or leg provide strong protection against prolonged interruption of blood flow to a target organ (e.g., heart or lung). This is known as remote ischemic preconditioning (RIPC). The strongest protection occurs 24 hours after blood flow interruption to the limb and may be mediated by a humoral cascade known as kallikrein-kinin. RIPC may provide protection against heart attack and stroke.
Linking Early Heart Growth Stress And Adult Cardiopathology: A New Role For Autophagy
Funder
National Health and Medical Research Council
Funding Amount
$524,013.00
Summary
An enlarged heart at maturity is a major risk factor. The goal of this project is to understand how cardiac growth abnormality in the neonate contributes to adult growth pathology. We have recently discovered that a type of stress-triggered cell death (autophagy) is increased in rodent neonatal hearts which later become enlarged, and that this cell death is regulated by the hormone angiotensin II. We will study the mechanisms involved to identify intervention opportunities to normalize growth.
STudy Of Risk Assessment To Reduce Complications In Patients Following Noncardiac SurgerY (STRATIFY)
Funder
National Health and Medical Research Council
Funding Amount
$436,000.00
Summary
Cardiac problems account for many complications in patients undergoing major non-cardiac surgery, and even apparently minor cardiac damage is a marker of high risk for subsequent adverse events. Unfortunately, while money and effort is expended on identifying patients at risk, the appropriate response to this risk is quite unclear. The performance of bypass surgery or balloon angioplasty in order to treat the underlying coronary disease of at-risk patients is used in other situations, and reduce ....Cardiac problems account for many complications in patients undergoing major non-cardiac surgery, and even apparently minor cardiac damage is a marker of high risk for subsequent adverse events. Unfortunately, while money and effort is expended on identifying patients at risk, the appropriate response to this risk is quite unclear. The performance of bypass surgery or balloon angioplasty in order to treat the underlying coronary disease of at-risk patients is used in other situations, and reduces longterm risk. However, in many patients undergoing major noncardiac surgery, this approach may be inappropriately aggressive, as these patients are often elderly, have other diseases that make heart operations more difficult and risky than usual, and in any case may have a reduced life expectancy from the disease necessitating the operation. As the most critical issue is to ensure that patients undergo their surgery uneventfully, an alternative is the use of intensive medical therapy to protect the heart. This multicentre study, based at Brisbane hospitals that perform large numbers of major operations, will follow up patients for complications, and outcome (including quality of life) will be assessed six months after the operation. We will address two important questions about the efficacy and cost of risk reduction strategies. First, in patients at higher levels of risk and with a positive stress test, could a combination of medical therapy designed to protect the heart be as effective as current approaches, which include the performance of bypass surgery or coronary balloon angioplasty? Second, in patients identified as being at some risk - but low risk - are drugs sufficiently effective to avoid the need for further testing to quantify risk? As the population continues to age, the numbers of at risk patients undergoing major surgery will increase, and answers to these questions will provide important information to guide their management.Read moreRead less
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