Early Events In Arteriolar Remodeling: Adaptation To Prolonged Vasoconstriction
Funder
National Health and Medical Research Council
Funding Amount
$415,750.00
Summary
Small arteries, while acutely responding to their environment with changes in diameter to regulate local blood flow and pressure, also undergo structural adaptation or remodelling. These events occur over a range of time-frames and involve both non-genetically and genetically regulated events. Thus a contractile event, while initially decreasing vessel diameter, also activates longer time frame processes which can span from rearrangment of cellular junctions-contacts to overt structural changes ....Small arteries, while acutely responding to their environment with changes in diameter to regulate local blood flow and pressure, also undergo structural adaptation or remodelling. These events occur over a range of time-frames and involve both non-genetically and genetically regulated events. Thus a contractile event, while initially decreasing vessel diameter, also activates longer time frame processes which can span from rearrangment of cellular junctions-contacts to overt structural changes within the vessel wall (for example thickening of the muscle layer). These adaptive processes may enable the forces of contraction to be maintained without continued energy expenditure and damage to the vessel per se. However, they can also contribute to long-term alterations in the control of blood pressure and perhaps contribute to states of hypertension as well as other common vascular diseases. For these studies we will use arterioles, isolated by microsurgical techniques, together with sophisticated computer and video-based approaches. These techniques allow arterioles to be studied under controlled conditions and relevant biochemical measurements performed. We will also use a cell model where cultured cells will be studied after defined periods of mechanical stimulation (for example stretch). Cells will be probed using a novel microscopic technique (atomic force microscopy) which enables the cell membrane to be studied with respect to changes in composition as well as physical characteristics (for example stiffness). The studies are relevant to our understanding of the normal adaptive processes occurring within blood vessels to control blood flow and pressure. The studies are also of direct relevance to our understanding of common vascular disease states including hypertension, complications of diabetes and chronic inflammatory disorders.Read moreRead less
Anti-atherosclerotic Effects Of Angiotensin Fragments & Non-AT1 Receptors: Validation As Innovative Therapeutic Targets
Funder
National Health and Medical Research Council
Funding Amount
$512,065.00
Summary
In Australia the largest cause of death is coronary heart disease (CHD) leading to heart attacks or stroke and claiming a staggering 28,000 lives a year. Atherosclerosis is one of the leading causes of cardiovascular disease, with diseased vessels not able to fully dilate and the plaque that has built up inside these vessels impeding blood flow and possibly rupturing, resulting in heart attacks and stroke. One of the major players in the development and progression of atherosclerosis is the horm ....In Australia the largest cause of death is coronary heart disease (CHD) leading to heart attacks or stroke and claiming a staggering 28,000 lives a year. Atherosclerosis is one of the leading causes of cardiovascular disease, with diseased vessels not able to fully dilate and the plaque that has built up inside these vessels impeding blood flow and possibly rupturing, resulting in heart attacks and stroke. One of the major players in the development and progression of atherosclerosis is the hormone, angiotensin II. Angiotensin II has been found to trigger many factors that cause thickening of the vessel wall, inflammation and imbalances in vasodilator capacity (e.g. oxidative stress and endothelial dysfunction), all of which contribute to atherosclerosis. Clinical trials with drugs that inhibit the formation of angiotensin II (ACE inhibitors), or block the action of angiotensin II (angiotensin receptor antagonists), have demonstrated a significant decrease in mortality in patients with high risk for cardiovascular disease. However their mechanism(s) of action are not fully understood as the circulating levels of shorter fragments of angiotensin II (such as Ang IV and Ang (1-7)) are raised in the blood when these drugs are used and may contribute to the protective effects of these drugs. Importantly, we have found that both Ang IV and Ang (1-7) have protective effects in atherosclerotic blood vessels. Therefore, we hypothesise that fragments of angiotensin II (such as Ang IV and others) exert anti-atherogenic effects via distinct binding sites that oppose the effects caused by angiotensin II, and that these may be partly responsible for the cardio-protective effects of the ACE inhibitors and angiotensin receptor antagonists. Thus, information gained in our study will be useful in directing future prescription practices in clinical management of CHD and stroke, and for designing new therapeutic compounds for the management of atherosclerosis.Read moreRead less
The Role Of Platelet Derived Growth Factor Receptor Alpha (Pdgfra) In Coronary Vascular Progenitor Cells
Funder
National Health and Medical Research Council
Funding Amount
$666,840.00
Summary
The coronary vessels supply blood to heart muscle. Blockage of coronary vessels causes heart attacks which are the leading cause of death in the Western world. A recent focus for heart attack researchers is to re-establish the blood supply to the injured area by creating new blood vessels. We have found a new gene involved in creating coronary blood vessels. We will characterize how this gene is involved in this process. Knowledge about this gene may foster new treatments for heart attack.
Improving Immunotherapy By Vascular Targeting And Barrier Alteration
Funder
National Health and Medical Research Council
Funding Amount
$526,878.00
Summary
Tumors grow in part because they escape destruction by the immune system. New blood vessels grow inside tumors by a process called angiogenesis, which then stops cancer-fighting cells in their tracks. We hypothesise that breaking down the blood-tumor barrier will open tumors for attack by the cancer-fighting immune system. This proposal continues our work on reversal of angiogenesis in the context of immunotherapy. We expect these findings to lead to highly effective anti-tumor therapies.
Characterisation Of PAR2 Knockout And Transgenic Mice: Towards Gene Therapy For Epithelia Based Inflammatory Diseases
Funder
National Health and Medical Research Council
Funding Amount
$486,943.00
Summary
Debilitating and sometimes fatal diseases like asthma and rheumatoid arthritis urgently require new approaches for their effective management and hopefully, cure. We have recently discovered that the airways posses a powerful and naturally-occuring protective mechanism which is regulated by unique molecules in the membranes of the lining cells of the air passages. These molecules are called protease-activated receptors, or PARs, and are also found on cells lining the inner surfaces of blood vess ....Debilitating and sometimes fatal diseases like asthma and rheumatoid arthritis urgently require new approaches for their effective management and hopefully, cure. We have recently discovered that the airways posses a powerful and naturally-occuring protective mechanism which is regulated by unique molecules in the membranes of the lining cells of the air passages. These molecules are called protease-activated receptors, or PARs, and are also found on cells lining the inner surfaces of blood vessels and joints as well as in skin. We are fortunate to have strains of mice - a species in which the PAR-mediated protective mechanism is well developed - in which the gene for the most important of the PARs found in the lung, PAR2, is missing. These animals are called PAR2 'knock-outs'. We also have another strain of mouse in which the human PAR2 gene has been inserted back into PAR2 knock-out mice. These animals will allow us to determine the importance of PAR2 in protection against asthma, arthritis, vascular disease and deficiencies in skin healing, as well as how PAR2 might be a more effective protective agent in mice rather than humans. Thus, modification of the human gene to make the protective system work as effectively as in the mouse might provide an effective therapy or cure for diseases of the lungs, joints and skin as well as in vascular diseases.Read moreRead less
Myoendothelial Gap Junctions: Their Composition And Role In Vasodilator Responses Attributed To EDHF
Funder
National Health and Medical Research Council
Funding Amount
$282,750.00
Summary
Cardiovascular disease, including coronary heart disease and stroke, continues to be the major cause of death in Australia and hypertension is a significant risk factor. The endothelium, which lines blood vessels of all sizes, is critical to the control of blood flow to the organs of the body. Endothelial cells release factors which can cause blood vessels to constrict or to relax, thus decreasing or increasing blood flow, respectively. Under normal conditions, the endothelium is more important ....Cardiovascular disease, including coronary heart disease and stroke, continues to be the major cause of death in Australia and hypertension is a significant risk factor. The endothelium, which lines blood vessels of all sizes, is critical to the control of blood flow to the organs of the body. Endothelial cells release factors which can cause blood vessels to constrict or to relax, thus decreasing or increasing blood flow, respectively. Under normal conditions, the endothelium is more important as a source of relaxing factors, while under hypertensive conditions, the balance is shifted in favour of the release of constricting factors. Thus, restoration of the vasodilatory function of the endothelium is seen as an important new therapeutic target in the treatment of vascular disorders. Present data suggests that the action of one of the major endothelial derived vasodilatory factors, the so-called endothelium-derived hyperpolarizing factor, EDHF, requires the presence of particular structures within the vascular wall, but little is known about the molecules of which they are comprised. We have identified two unique situations, during development and during hypertension, when these structures are present in vessels in which they are absent in normal adults. We will use gene microarrays to identify the specific molecules involved in these structures and use physiological studies to test the role of these proteins and structures in vasodilatory responses. The results of these studies may identify new targets for therapeutic intervention to restore the action of EDHF in hypertension.Read moreRead less
Characterisation Of MiRNAs That Regulate Vascular Leakage.
Funder
National Health and Medical Research Council
Funding Amount
$167,493.00
Summary
Vascular permeability or leak is a major problem in diseases such as cancer and in cardiovascular diseases . MicroRNAs (miRNAs) are small control genes that influence dveleopment and disease. We have identified a miRNA cluster in endothelial cells, the cells that line the blood vessels, that is important in the control of vascular leak. This project is focused on understanding the impact of these miRNAs in disease.
Role Of Epigenomic Changes In Conferring Hyperglycemic Memory
Funder
National Health and Medical Research Council
Funding Amount
$636,146.00
Summary
The major burden of type I diabetes remains its vascular complications including diabetes-accelerated athersclerosis. Despite improved glucose control, diabetic individuals develop complications as a result of prior poor glycemic control. Although the development and progression of these diabetic complications is strongly associated with mean levels of glucose, recent studies suggest that the deleterious effects of early exposure to high levels of glucose persist for years even after treatment h ....The major burden of type I diabetes remains its vascular complications including diabetes-accelerated athersclerosis. Despite improved glucose control, diabetic individuals develop complications as a result of prior poor glycemic control. Although the development and progression of these diabetic complications is strongly associated with mean levels of glucose, recent studies suggest that the deleterious effects of early exposure to high levels of glucose persist for years even after treatment has returned glucose levels towards normal.Read moreRead less