The Role Of Osteocytes In Particle Induced Osteolysis
Funder
National Health and Medical Research Council
Funding Amount
$457,196.00
Summary
Hip replacements often fail due to the loss of adjacent bone. Metal or polyethylene particles are produced as the prosthesis bearing surface wears but how do these particles lead to bone loss? Our work suggests involvement of osteocytes within the bone mineral, which are increasingly understood to drive bone physiology and pathology. We will explore the role of the osteocytes by examining their response to particles, which may identify a new target to prevent particle-induced bone loss.
We will seek to address an important clinical problem in orthpaedics, namely the bone loss that commonly occurs around joint replacement prostheses. Termed peri-prosthetic osteolysis (PO), this bone loss can result in the loosening and ultimate failure and need for revision of the artificial joint components. PO is thought to be caused by the body's reaction to wear particles generated from the articulating surface of the prosthesis. However, it has not previously been possible to accurately exp ....We will seek to address an important clinical problem in orthpaedics, namely the bone loss that commonly occurs around joint replacement prostheses. Termed peri-prosthetic osteolysis (PO), this bone loss can result in the loosening and ultimate failure and need for revision of the artificial joint components. PO is thought to be caused by the body's reaction to wear particles generated from the articulating surface of the prosthesis. However, it has not previously been possible to accurately explore the relationship between prothesis wear and PO, or the progression of PO, because of a lack of techniques to image and measure the volume of PO around metal prosthesis components. We have developed a means to accurately and reproducibly measure the volume of bone loss, using CT, and will do so longitudinally in joint replacement patients to obtain the first information about the progression of PO. New computer based methods will be used concurrently to relate prosthesis wear and migration parameters to PO. Patients who come to surgery for replacement of failed prostheses will be investigated further by analysis of the tissues involved in the bone loss around prostheses. Basic science experiments will seek to understand the underlying causes of PO and the findings will be important in interpreting the clinical results. An animal model will be used to seek approaches to inhibiting the pathological response to wear particles. The significance of these studies is that they will lead to improved outcomes for joint replacement patients, increasing the interval to revision surgery, which is both extremely costly and brings an attendant morbidity and mortality.Read moreRead less
Impaired Bone Remodelling Leads To Failure Of Orthopaedic Prostheses
Funder
National Health and Medical Research Council
Funding Amount
$515,917.00
Summary
The failure of bone prostheses is becoming a major health problem. More than 26,000 hip, and an equal number of knee, replacements were performed in Australia in 2002 with the number increasing between 5%-10% each year for the previous 10 years. Disturbingly, the incidence of revision hip surgery in Australia is now more than 15%, meaning that, despite the impressive success of joint replacement surgery, a significant number of arthroplasties fail. It is becoming more common for young, active in ....The failure of bone prostheses is becoming a major health problem. More than 26,000 hip, and an equal number of knee, replacements were performed in Australia in 2002 with the number increasing between 5%-10% each year for the previous 10 years. Disturbingly, the incidence of revision hip surgery in Australia is now more than 15%, meaning that, despite the impressive success of joint replacement surgery, a significant number of arthroplasties fail. It is becoming more common for young, active individuals to receive joint replacement surgery to improve their quality of life. This, combined with increasing life expectancy, and the known higher rate of failure of joint replacements in younger patients, means that the morbidity of a failed replacement, and the mobidity and associated mortality of revision surgery, will become an increasingly important health issue, with a major impact upon health budgets. The overwhelming majority of hip and knee prostheses have metal or ceramic on polyethylene bearing surfaces. It is now apparent that most implants fail due to bone loss around them leading to loosening, and evidence is accumulating that polyethylene wear particles are a major contributing factor to this process. It is therefore vital that we obtain better understanding of the causes of implant failure in order to extend the life of these implants and this project is designed to do so.Read moreRead less
Regulation Of VEGFR Trafficking And Signal Transduction By The Ubiquitin Ligase Nedd4
Funder
National Health and Medical Research Council
Funding Amount
$388,347.00
Summary
Our recent work has discovered that the Nedd4 gene is crucial for the growth and development of blood vessels and lymphatic vessels. Our data suggest that Nedd4 controls vessel growth by regulating the levels and signalling activity of the key vascular growth factor receptors VEGFR-2 and VEGFR-3. The goals of this proposal are to define precisely how Nedd4-1 regulates the activity of these receptors and how VEGFR signalling could be better targeted to treat vascular disorders.
Regulation Of Key Pathways Causing Peri-implant Bone Loss.
Funder
National Health and Medical Research Council
Funding Amount
$403,639.00
Summary
The failure of bone prostheses is becoming a major health problem in our aging population. Despite the impressive success of joint replacement surgery, a significant number of arthroplasties fail. It is now apparent that most implants fail due to bone loss around them which leads to loosening. This project aims to obtain a better understanding of the causes of implant failure and find ways to extend the life of these implants .
Role For Zinc And ZIP2 In The Action Of Nitric Oxide And In Vascular Protection Against Cigarette Smoke And Cardiovascular Disease
Funder
National Health and Medical Research Council
Funding Amount
$685,941.00
Summary
The NO/cGMP signalling pathway, which is central to cardiovascular physiology and protection against disease, is only fully effective when there are adequate levels of zinc in the vascular endothelium. This is especially important where zinc stores are depleted (elderly, smokers, diabetics and kidney disease). There is an urgent clinical need to implement strategies to monitor vascular Zn status. This application will explore the underlying science and translate these to the clinic.
Defining The Role Of The Ubiquitin Protein Ligase Nedd4 In Vascular Development.
Funder
National Health and Medical Research Council
Funding Amount
$702,166.00
Summary
Blood and lymphatic vessels are vital components of the cardiovascular system. Abnormalities in the growth and development of these vessels are associated with human disorders including cancer and cardiovascular disease. The focus of this application is to characterise the role of the ubiquitin protein ligase Nedd4 in vascular development, with the aim of identifying targets to which novel therapeutics for the treatment of blood and lymphatic vascular diseases could be generated.
Vascular Contributions To Dementia: Prevention In Those At High-risk
Funder
National Health and Medical Research Council
Funding Amount
$718,105.00
Summary
10,000 older adults undergo surgeries on their heart every year. These adults are at high risk for dementia, as the factors that bring them to cardiovascular surgery are the same as those that associate with dementia: hypertension, type II diabetes, etc. This population is in fact not only at increased risk of dementia due to vascular ill-health, but also because of undergoing the surgery itself. This project aims to prevent dementia in this vulnerable group.
Understanding How GATA2 Controls Lymphatic Vessel Valve Development
Funder
National Health and Medical Research Council
Funding Amount
$697,942.00
Summary
Mutations in the GATA2 gene cause human lymphoedema as a result of the crucial role that GATA2 plays in controlling the expression of genes important for building functional lymphatic vessels. Here we aim to gain a complete picture of the cellular and molecular events that are controlled by GATA2 in lymphatic vessels and in particular, in lymphatic vessel valves.