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
Determination Of Irradiation Dose Efficacy For Use In Impaction Grafting At Revision Joint Replacement
Funder
National Health and Medical Research Council
Funding Amount
$411,517.00
Summary
Primary hip replacement is a successful intervention for hip disease, but 10-15% of hip prostheses fail and require revision surgery within 10-15 years. At the time of revision, significant bone loss around the failed prosthesis is not uncommon. A bone reconstruction procedure, called impaction grafting, where donor bone is minced and placed in the areas of deficient bone before implanting the new prosthesis, has shown to give good results at more than ten years in some centres. A high incidence ....Primary hip replacement is a successful intervention for hip disease, but 10-15% of hip prostheses fail and require revision surgery within 10-15 years. At the time of revision, significant bone loss around the failed prosthesis is not uncommon. A bone reconstruction procedure, called impaction grafting, where donor bone is minced and placed in the areas of deficient bone before implanting the new prosthesis, has shown to give good results at more than ten years in some centres. A high incidence of early complications of this procedure have included loss of fixation within the bone. Fracture of the bone around prostheses has also reported in some centres. These events require more surgery, putting the patient at higher risk greater complications and longer rehabilitations. Recent improvements in surgical technique and donor bone preparation have improved results. A current debate questions whether the dose of irradiation can be reduced from 25 kGy, while maintaining sterility of allografts. The risk of bacterial contamination in allografts is low, and irradiation reduces the mechanical strength of the graft, contributing to complications when irradiated bone is used. The benefits of decontaminating the bone may be outweighed by the higher risk for failure due to poor bone quality and resulting prosthesis instability. We will use ISO standards to test the validity of radiation dose for sterilising bone ex vivo. In the absence of controlled human studies, our aim is also to compare the results of impaction grafting with non-irradiated bone versus bone irradiated at current doses used by Australian bone banks, and lower doses indicated by ex vivo testing. We will use a large animal model of revision hip replacement, with precise measures of prosthesis stability. The results of this study will guide clinical decisions regarding the efficacy of current bone graft preparation procedures and the use of irradiated bone in human hip replacement surgery.Read moreRead less
The Risks And Benefits Of Contemporary Total Hip Replacement
Funder
National Health and Medical Research Council
Funding Amount
$493,530.00
Summary
The number of hip replacements undertaken in Australia is steadily increasing. The most common complications of hip replacements are dislocation and loosening due to bone loss around the implant, requiring complex and expensive revision surgery. This study will investigate the incidence of dislocation and, using a new diagnostic imaging technique, the incidence and amount of bone loss around a relatively new prosthetic material, the outcomes of which are not known despite its increasing use.
Mechanisms Of Premature Cranial Fusion: Role Of Retinol Binding Protein 4 In Osteogenesis And Suture Fusion
Funder
National Health and Medical Research Council
Funding Amount
$555,855.00
Summary
Craniosynostosis is a condition where the skull bones fuse prematurely, affecting skull shape, vision and cognition. It occurs in 1 in 2,500 births. The only treatment is surgery, which is life-threatening, costly and may need to be repeated. By studying how fusion happens in this project we may be able to devise therapies to minimize the risks and need for re-operation. Here, we hope to show that modification of a single substance in the skull of mouse models can prevent premature bone fusion.
Tyrosine Kinase Receptor C-ros-oncogene 1 Mediates Twist-1 Haploinsufficiency Induced Craniosynostosis In Children: A Novel Therapeutic Target
Funder
National Health and Medical Research Council
Funding Amount
$562,863.00
Summary
Children with Saethre-Chotzen syndrome exhibit premature fussed coronal sutures, and other skull/ skeletal malformations. Surgical intervention is the only treatment option to ensure optimal cognitive and skeletal development. Our studies have identified a candidate molecular pathway that regulates bone formation by cranial bone cells from these patients. Targeting these key molecular signalling components with chemical inhibitors will help prevent the premature fusion of cranial sutures.
Histone Demethylase KDM6A Is A Novel Target For Treating Craniosynostosis In Children With Saethre-Chotzen Syndrome
Funder
National Health and Medical Research Council
Funding Amount
$548,854.00
Summary
Children with Saethre-Chotzen syndrome exhibit premature fused coronal sutures, and other skull/ skeletal malformations. Surgical intervention is the only treatment option to ensure optimal cognitive and skeletal development. Our studies have identified a candidate molecular pathway that regulates bone formation by cranial bone cells from these patients. Targeting this key molecular regulator with chemical inhibitors will help prevent the premature fusion of cranial sutures.
Identifying Target Genes For Novel Anti-epileptic Therapies In The Mouse
Funder
National Health and Medical Research Council
Funding Amount
$469,802.00
Summary
Epilepsy is a disease which affects 2-4% of the population. There are a wide range of drugs available to treat the condition but there is consistently 30-40% of patients who do not respond well to any of these drugs and who continue to have seizures. The reason that there are no drugs available for these people is that most of the drugs available have been designed along the same principles. A new set of principles is needed to develop new drugs which will be able to treat those people not respo ....Epilepsy is a disease which affects 2-4% of the population. There are a wide range of drugs available to treat the condition but there is consistently 30-40% of patients who do not respond well to any of these drugs and who continue to have seizures. The reason that there are no drugs available for these people is that most of the drugs available have been designed along the same principles. A new set of principles is needed to develop new drugs which will be able to treat those people not responding to current therapy. This project is designed to identify new biologic pathways which may be interrupted with drugs to prevent seizures in people with epilepsy. This project uses a procedure to induce mutations into genes in mice and then screens for mice which do not seize when challenged with a drug which generates seizures in mice. Genetic studies will identify the mutated genes and these will be used as potential targets for new therapies or will identify new biological pathway which should expand the use of future anti-epileptic drugs.Read moreRead less
Understanding And Overcoming Cardiovascular And Diabetes Inequalities In Indigenous Australians
Funder
National Health and Medical Research Council
Funding Amount
$707,370.00
Summary
Aboriginal and Torres Strait Islanders experience the highest rates of heart disease and diabetes of all Australians. The reasons for this large disparity is not yet fully understood. I propose to investigate the patterns, causes, complications and links between heart disease and diabetes in Indigenous populations to identify better ways of managing and preventing chronic disease in high risk communities.
Targeting RCAN1 To Treat Type 2 Diabetes And Obesity
Funder
National Health and Medical Research Council
Funding Amount
$814,468.00
Summary
Obesity and impaired insulin secretion are significant contributors to Type 2 diabetes. In this project we demonstrate that a protein called RCAN1 contributes to both fat mass and insulin secretion and that this contribution is exacerbated in obesity and in Type 2 diabetes. We will identify how RCAN1 controls these major metabolic pathways with outcomes including the development of new therapeutics for obesity and Type 2 diabetes.