Determinants Of Circulating Surfactant Protein Levels In Health And Disease
Funder
National Health and Medical Research Council
Funding Amount
$276,221.00
Summary
The lung allows the oxygenation of blood and clearance of carbon dioxide. To achieve this a large surface area (50-100 m2) interfaces with a complex microcirculation across a 0.1-0.2 ?m barrier - the alveolocapillary membrane. The alveolocapillary membrane is damaged under a variety of circumstances, of varying severity. Whereas severe impairment results in respiratory failure, often there is no clear delineation between OacceptableO and OpathologicalO changes. Therefore, we have coined the term ....The lung allows the oxygenation of blood and clearance of carbon dioxide. To achieve this a large surface area (50-100 m2) interfaces with a complex microcirculation across a 0.1-0.2 ?m barrier - the alveolocapillary membrane. The alveolocapillary membrane is damaged under a variety of circumstances, of varying severity. Whereas severe impairment results in respiratory failure, often there is no clear delineation between OacceptableO and OpathologicalO changes. Therefore, we have coined the term Olung healthO to encompass the broad spectrum. Generally speaking, lung health can be compromised by lifestyle or disease. Whereas lifestyle changes are typically progressive and chronic, those associated with disease tend to be severe and acute. Monitoring lung health clearly has important implications in terms of occupational health and lifestyle issues, including smoking. The need for a marker of lung permeability is also regarded as the Oholy grailO in the intensive care setting. Currently, there is no way of doing so. The alveolus is lined with a liquid layer into which is secreted a complex mixture of lipids and specific proteins known as alveolar surfactant. Surfactant reduces the work of breathing. Recently, we fortuitously discovered that surfactant proteins leak into the circulation and that changes in their levels are a sensitive and early generic index of the lung?s integrity. We discovered that lung damage from conditions as diverse as smoking to the acute respiratory distress syndrome elevate circulating surfactant proteins levels. To refine our discovery we aim to: Improve the techniques used to measure the proteins Study the rate at which they enter and clear the circulation Study the influence of storage, gender, age, circadian rhythm, and smoking on the levels Study the levels in acute lung injury and in radiotherapy and cytotoxic drug treatment where the ability to monitor lung damage has immediate benefit for the patients.Read moreRead less
Deciphering Signalling Pathways Regulating Iron Homeostasis
Funder
National Health and Medical Research Council
Funding Amount
$407,402.00
Summary
Iron overload and anaemia are two of the most significant health problems affecting humans. Understanding how the body regulates iron levels is key to our understanding of these disorders and to the future development of new therapies. This research is aimed at understanding how a hormone produced in the liver called hepcidin that maintains iron balance is regulated. This research may lead to novel therapies aimed at correcting the iron balance in conditions of iron overload or anaemia.
Mitochondrial Iron Overload And Friedreich's Ataxia: The Role Of Frataxin In Iron And Haem Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$285,990.00
Summary
Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. Recent studies using Baker's yeast have shown that the deletion of frataxin results in the accumulation of toxic iron in the mitochondrion. More recently, a variety of studies have shown that FA patients have iron loading within their cells. The iron build-up may cause severe damage. At present, the role of frataxin in mammalian mitochondrial iron metabolism is unknown. Our preliminary studies demonstrate that frataxin i ....Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. Recent studies using Baker's yeast have shown that the deletion of frataxin results in the accumulation of toxic iron in the mitochondrion. More recently, a variety of studies have shown that FA patients have iron loading within their cells. The iron build-up may cause severe damage. At present, the role of frataxin in mammalian mitochondrial iron metabolism is unknown. Our preliminary studies demonstrate that frataxin is down-regulated by either erythroid differentiation or the haem precursor protoporphyrin IX (Becker and Richardson, submitted). These data strongly suggest a role for frataxin in iron metabolism. In the present study we will continue to assess if frataxin plays a role in the way cells handle iron. Using a unique model of mitochondrial iron overload developed in my lab (Richardson et al. (1996) BLOOD 87:3477), we will extensively investigate the iron metabolism of the mitochondrion in order to determine the function of frataxin and its role in Friedreich's ataxia. In addition, we have developed a series of new drugs known as iron chelators that can enter the mitochondrion due to their high lipid solubility (Becker and Richardson 1999 J. Lab. Clin. Med. 134:510). These latter drugs are far more effective than the chelator currently used to treat iron overload, desferrioxamine (DFO). Indeed, our chelators have been designed to result in high iron chelation efficacy but low toxicity (see Becker and Richardson, 1999). This exciting research may be crucial in understanding the development of FA and in creating new therapies such as the use of iron chelators.Read moreRead less
A Phase II Randomised Controlled Trial Of Atorvastatin Therapy In Intensive Care Patients With Severe Sepsis
Funder
National Health and Medical Research Council
Funding Amount
$622,148.00
Summary
Infections are common in patients in the intensive care unit and produce inflammation that may spread throughout the body. Despite improved therapies, when infections cause failure of the body's vital organs, up to 40% of patients may die. The medication atorvastatin and other statins have been used for many years to treat and prevent conditions such as heart attack and stroke. They act primarily by reducing cholesterol production. In addition, they also modify inflammation and the immune system ....Infections are common in patients in the intensive care unit and produce inflammation that may spread throughout the body. Despite improved therapies, when infections cause failure of the body's vital organs, up to 40% of patients may die. The medication atorvastatin and other statins have been used for many years to treat and prevent conditions such as heart attack and stroke. They act primarily by reducing cholesterol production. In addition, they also modify inflammation and the immune system which may make them a useful treatment for patients with established infections. Although the statin drugs are usually safe, rare side effects may affect muscle and the liver. Because of concerns about increased risk of side effects it is currently recommended that statins should be stopped when patients become unwell. However, a number of studies have suggested that patients on statins for heart disease are less likely to develop infections and that their infections are less likely to be severe or result in death. Other studies have suggested that stopping statins in patients that present with infections (as suggested by current guidelines), may worsen infection outcomes. However, these studies have not been detailed enough to exclude all factors affecting outcome, such as patient age, severity of the infection, and the presence of other diseases. We plan to perform a study to assess the effect of atorvastatin on the outcome of infections in the intensive care unit. We will study 250 patients presenting with severe infections. We will randomly assign patients to receive either atorvastatin or placebo and monitor the effect on signs of inflammation and levels of life support. Outcomes and side effects will be carefully monitored. The study will help us decide whether to perform a larger study to determine if atorvastatin can reduce the risk of dying from serious infections.Read moreRead less
EXAMINING THE RELATIONSHIP BETWEEN MATRIPTASE-2 AND HEMOJUVELIN, TWO ESSENTIAL REGULATORS OF IRON HOMEOSTASIS
Funder
National Health and Medical Research Council
Funding Amount
$533,541.00
Summary
The control of iron levels is important in health and well being. Too little can lead to iron deficiency and anaemia, conversly too much can lead to haemochromatosis and tissue damage. We will examine the role of two proteins, matriptase-2 and hemojuvelin that when mutated cause iron deficiency or iron overload respectively. We will study how these proteins interact and work in opposite directions to control iron levels. The results will help to develop new therapeutics for iron disorders.
Non-invasive Measurement And Imaging Of Hepatic Iron Concentrations Using Nuclear Magnetic Resonance
Funder
National Health and Medical Research Council
Funding Amount
$341,210.00
Summary
Iron overload diseases such as genetic haemochromatosis and thalassaemia affect up to 0.5% of the world's population. These diseases result in deposition of dangerously high concentrations of iron in tissues of the body. Organs such as the liver and heart are at particular risk of being damaged. In order to manage a patient's condition optimally, a knowledge of their tissue iron concentrations is required. Currently the most direct and reliable way of achieving this is to remove a small sample o ....Iron overload diseases such as genetic haemochromatosis and thalassaemia affect up to 0.5% of the world's population. These diseases result in deposition of dangerously high concentrations of iron in tissues of the body. Organs such as the liver and heart are at particular risk of being damaged. In order to manage a patient's condition optimally, a knowledge of their tissue iron concentrations is required. Currently the most direct and reliable way of achieving this is to remove a small sample of the patient's liver for chemical analysis. Apart from the fact that the procedure is unpleasant and carries some risk, the measurement made by this method has some uncertainty because the liver iron concentration can vary significantly from place to place within the liver. The aim of this project is to test the validity of a new non-invasive method of measuring and imaging the liver iron concentrations of a patient. In addition, the potential to use the new technology for detecting and imaging liver cirrhosis in iron overloaded patients will be evaluated. If successful, the project may lead to a more accurate method of measuring tissue iron concentrations and eliminate the need for invasive procedures.Read moreRead less
Too little or too much of the essential element iron is the cause of some of the most common disorders affecting humans. These include iron overload, anaemia, and anaemia of chronic disease. This project examines the genes and the roles they play in regulating iron levels in the body, and the consequences to the individuals when they are mutated. Ultimately I intend to develop therapeutics and diagnostics which will help early diagnosis and effective treatment of these disorders.