Interaction Of Angiotensin II And PPARg In Aortic Aneurysm Formation
Funder
National Health and Medical Research Council
Funding Amount
$427,398.00
Summary
Between 5% to 10% of men and 1% of women over the age of 60 years develop weakening of their main abdominal artery leading to slow dilation of the vessel. If this process continues long term the artery can burst resulting in sudden death. At present the only treatment available for this problem is surgery, either open or minimally invasive. Both these forms of treatment are associated with significant complications and unsuitable for some patients. Thus the development of a drug treatment which ....Between 5% to 10% of men and 1% of women over the age of 60 years develop weakening of their main abdominal artery leading to slow dilation of the vessel. If this process continues long term the artery can burst resulting in sudden death. At present the only treatment available for this problem is surgery, either open or minimally invasive. Both these forms of treatment are associated with significant complications and unsuitable for some patients. Thus the development of a drug treatment which can slow or halt the weakening and dilation of the aorta would have great patient benefits. We have identified an important role for a newly discovered protein in weakening of the abdominal aorta. In this study we investigate the role of a pathway which appears to be fundamental in generating this protein. In particular we will assess the role of drug treatment in blocking this pathway as a basis for medical treatment for artery weakening.Read moreRead less
Role Of Osteoprotegerin In Protecting The Diabetic Aorta From Aneurysm Formation
Funder
National Health and Medical Research Council
Funding Amount
$299,250.00
Summary
Between 5% and 10% of men over the age of 60 years develop weakening of their main abdominal artery (aorta) leading to slow dilation of the vessel. If this process continues long term the artery can burst resulting in sudden death. At present the only treatment available for this problem is surgery, either open or minimally invasive. Both these forms of treatment are associated with significant complications and unsuitable for some patients. Thus the development of a drug treatment which can slo ....Between 5% and 10% of men over the age of 60 years develop weakening of their main abdominal artery (aorta) leading to slow dilation of the vessel. If this process continues long term the artery can burst resulting in sudden death. At present the only treatment available for this problem is surgery, either open or minimally invasive. Both these forms of treatment are associated with significant complications and unsuitable for some patients. Thus the development of a drug treatment which can slow or halt the weakening and dilation of the aorta would have great patient benefits'. Surprisingly patients with sugar diabetes are less likely to develop this form of artery weakening. This important negative association may form the basis of discovering a new medication to protect arteries from rupture. In this study we investigate the role of a recently discovered protein in protecting the main abdominal artery from weakening in diabetics. This protein is of particular interest for the following reasons: 1. It comes from a group of proteins believed to be important in artery calcium build-up. 2. Artery calcium is common in patients with diabetes who are relatively protected from aortic weakening. 3. It is being used for the treatment of bone weakening, appears to be safe in patients and therefore is a potential therapeutic agent. We believe this work is an important step towards the development of a successful medical treatment for artery weakening.Read moreRead less
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
Susceptibility To Venous Leg Ulceration: Investigation Of The First Genetic Risk Factor
Funder
National Health and Medical Research Council
Funding Amount
$291,000.00
Summary
This application aims to confirm our preliminary identification of the first candidate gene as a risk factor for developing venous leg ulceration. Since patients with venous leg ulcers experience pain and psychological consequences including anger and depression, all of which impact negatively on quality of life, active prevention of ulceration will have significant lifestyle and financial benefits. Venous leg ulcers occur in patients who have venous disease, in particular in patients with previ ....This application aims to confirm our preliminary identification of the first candidate gene as a risk factor for developing venous leg ulceration. Since patients with venous leg ulcers experience pain and psychological consequences including anger and depression, all of which impact negatively on quality of life, active prevention of ulceration will have significant lifestyle and financial benefits. Venous leg ulcers occur in patients who have venous disease, in particular in patients with previous deep vein thrombosis. However, not all patients with a deep vein thrombosis or other forms of venous disease will go on to develop a venous ulcer. Our preliminary results show that patients with a venous ulcer have a greater frequency of this gene than healthy controls without venous ulcers, and suggest that patients with the candidate gene have a greater risk of developing venous ulceration. In this study we aim to determine whether the gene itself contributes to ulcer susceptibility or whether it is just a marker of that susceptibility. We can do this by assessing related genes and the levels of the protein produced by this gene. In this study we also aim to assess whether patients with a proven deep vein thrombosis are more likely to develop venous ulceration if they have the candidate gene. These studies have the potential to lead to the development of a diagnostic screening test for use in patients with venous disease, to assess the likelihood of developing leg ulceration. This will enable more active treatment to prevent leg ulceration. If this gene contributes to ulcer susceptibility new specific treatments may be developed for ulcer management and prevention.Read moreRead less
THE ROLE OF RESIDENT MAST CELLS IN ISCHAEMIA-REPERFUSION INJURY OF SKELETAL MUSCLE.
Funder
National Health and Medical Research Council
Funding Amount
$226,320.00
Summary
NHMRC 209113 LAY DESCRIPTION Ischaemia reperfusion injury occurs in skeletal muscle when the blood-oxygen supply is cut off (ischaemia) and later restored (reperfusion). If the duration of ischaemia is short some of the muscle survives. However, when blood flow and oxygen are restored the muscle is subjected to more injury, which is thought to be caused by oxygen and-or white blood cells. This type of injury occurs in muscle which has been crushed, limbs that have been broken or traumatized, in ....NHMRC 209113 LAY DESCRIPTION Ischaemia reperfusion injury occurs in skeletal muscle when the blood-oxygen supply is cut off (ischaemia) and later restored (reperfusion). If the duration of ischaemia is short some of the muscle survives. However, when blood flow and oxygen are restored the muscle is subjected to more injury, which is thought to be caused by oxygen and-or white blood cells. This type of injury occurs in muscle which has been crushed, limbs that have been broken or traumatized, in replantation of amputated parts, in transplantation, after some surgical procedures and after microsurgical transfer of muscle. Once established there is no effective treatment. Our experiments show that a particular cell, the mast cell, and a particular molecule, nitric oxide, are involved in causing ischaemia reperfusion injury. However, the extent of their involvement is unknown. In this proposal we will investigate the effect of replacing mast cells into muscles, in a unique variety of mice which normally don t contain mast cells and are resistant to ischaemia reperfusion injury. In one group of mice we will put back normal mast cells and in a second group of mice we will put back mast cells that cannot produce the nitric oxide molecule. These experiments will determine, unambiguously, the extent of involvement of mast cells and mast cell-derived nitric oxide. In the second part of this proposal will carry out a time course study, using pharmacologically induced mast cell degranulation, to determine when the mast cells become injurious to skeletal muscle. These experiments will identify the period during which mast cell behaviour can be modulated in order to protect the muscle from ischaemia reperfusion injury. Determination of the role of mast cells, and an understanding of the timing during which they become injurious would provide a logical basis for optimizing drug therapy in clinical applications of these findings.Read moreRead less
GENERATION OF VASCULARISED, BIOENGINEERED SOFT TISSUES
Funder
National Health and Medical Research Council
Funding Amount
$445,045.00
Summary
One of the most exciting areas in reconstructive surgery today is the tissue engineering of body parts, the process by which blood vessels are implanted into skin, muscle, bone, cartilage or even synthetic materials, to build composite living structures. Once a circulation becomes established, the engineered part can be transferred by joining the implanted blood vessels to corresponding ones at the recipient site. We have discovered that new tissue will grow out of a surgically created blood ves ....One of the most exciting areas in reconstructive surgery today is the tissue engineering of body parts, the process by which blood vessels are implanted into skin, muscle, bone, cartilage or even synthetic materials, to build composite living structures. Once a circulation becomes established, the engineered part can be transferred by joining the implanted blood vessels to corresponding ones at the recipient site. We have discovered that new tissue will grow out of a surgically created blood vessel loop placed in a cylindrical plastic chamber filled with a scaffold made of naturally occurring structural molecules. In Part 1 of this project, it is planned to optimise the rate of new vascularised tissue growth through the addition to the growth chamber of various biodegradable scaffolds. In Part 2, we aim to produce fat by 3 possible methods using: (a) cells from the rat scrotum, (b) skeletal muscle separated from its blood supply for 24 hours, or (c) bone marrow-derived stem cells, as well as bone from stem cells of the same source. In Part 3, vascularised bone, fat and connective tissue, as produced in Part 2, will be microsurgically transferred to another site in the body to study the short-term (4 weeks) and long-term (12 weeks) survival and changes (if any) in these tissues. These unique methods are currently being patented. This technology introduces the possibility of producing tailor-made tissues of specific composition to suit the repair of a particular tissue type, for example, (1) myocutaneous flaps to replace tissue loss following traumatic injury, (2) bone for nose, digit or joint repair, and (3) fat to provide a bulky flap as required in contour defects of the face and neck. The development of new growth chambers of appropriate body shapes (eg. ears, noses, etc) has significant commercial implications.Read moreRead less
Engineering Tissues And Organs In Vivo From Stem Cells
Funder
National Health and Medical Research Council
Funding Amount
$549,480.00
Summary
Tissue engineering is an exciting new area of medical research. We have developed a unique animal model of tissue engineering where new tissue spontaneously sprouts from the surface of a vascular loop enclosed inside a plastic chamber. The tissue thus created has its own blood supply. By adding cultured cells or altering the environment of the chamber we have been able to grow new specific tissues such as fat and muscle. This technology potentially allows the generation of spare body parts to re ....Tissue engineering is an exciting new area of medical research. We have developed a unique animal model of tissue engineering where new tissue spontaneously sprouts from the surface of a vascular loop enclosed inside a plastic chamber. The tissue thus created has its own blood supply. By adding cultured cells or altering the environment of the chamber we have been able to grow new specific tissues such as fat and muscle. This technology potentially allows the generation of spare body parts to replace lost or worn out organs and tissues. We have recently reproduced this model in the mouse to be able to screen a range of mouse and human stem cells. These cells have the ability to change (i.e. differentiate) into many different types of cell depending on how they are stimulated. In Part 1 of this project we will determine in the mouse chamber the growth characteristics and survival rates of these stem cells. A chamber encapsulating a flowing blood vessel will be implanted subcutaneously in each groin. In one chamber we will inject fluorescently labelled stem cells in a growth medium and in the other growth medium alone. Tissue will be analysed at 1, 2 and 4 weeks. In Part 2 we will inject a variety of Rosa26 labelled mouse stem cells obtained from several different tissues. Through the aid of naturally occurring growth and differentiation factors they will differentiate into one of several different tissues including fat, cartilage, bone, neural tissue, blood vessels, liver, etc, which will be identified by histology and cell culture. In one experiment we will genetically alter cells injected into the chamber so that they produce only skeletal muscle. In Part 3 we will grow new human tissues by injecting human stem cells into the same tissue engineering chambers in mice which will tolerate cells from other mammals (these are known as SCID mice). Success in novel method would be the precursor for the production of new human tissues to repair specific defects.Read moreRead less
In Vivo Tissue Engineering Of Adipose Tissue For Reconstructive Surgery
Funder
National Health and Medical Research Council
Funding Amount
$713,545.00
Summary
We are able to grow vascularised tissue in implanted plastic chambers to a predetermined size and shape in the rat and mouse (NHMRC Project Grant 01-03; #145782; CIA Morrison). The basis of this growth is blood vessel sprouting from the surface of the vessel bundle or loop, followed by synthesis of structural molecules and the migration of surrounding cells into the vascularised network to form a stable tissue. Unlike other in vivo models of tissue engineering, the tissue grows spontaneously and ....We are able to grow vascularised tissue in implanted plastic chambers to a predetermined size and shape in the rat and mouse (NHMRC Project Grant 01-03; #145782; CIA Morrison). The basis of this growth is blood vessel sprouting from the surface of the vessel bundle or loop, followed by synthesis of structural molecules and the migration of surrounding cells into the vascularised network to form a stable tissue. Unlike other in vivo models of tissue engineering, the tissue grows spontaneously and is densely vascularised, enabling continuous growth and surgically transfer to another part of the body, or to another animal. In this renewal application of the above NHMRC grant, we propose to direct these findings towards the development of vascularised fat tissue which would be ideal for reconstructive surgery as a stable, inert tissue filler. Our efforts to grow fat tissue in vivo to date have identified 4 major requirements: a fat precursor cell source; an instructive basement membrane matrix (which may include growth-differentiation factors); space into which the tissue can grow; a stable blood supply. We will focus here on optimising the precursor cell source and instructive matrix to generate vascularised fat tissue around the blood supply we can engender in our tissue engineering chamber. We have found Matrigel, a mouse tumor-derived matrix rich in basement membrane components, to be instructive for growing fat, and will also build on preliminary observations that either muscle or fat tissue can provide the appropriate precursor cells for this process. Finally we propose to adapt and upsize the vascularised fat tissue chamber to the pig, in a step towards human use, and assess its transplantability and longevity. The clinical application of our work is to produce breast reconstruction tissue and lipo filling for contour deformities resulting from trauma, congenital deformity, ageing and cancer surgery, particularly breast reconstruction.Read moreRead less