Bone Fragility: The Neglected Role Of Cortical Porosity
Funder
National Health and Medical Research Council
Funding Amount
$620,381.00
Summary
Cortical (outer shell) or compact bone constitutes 80% of the skeleton. It is not solid as implied by its name but made of inter-connected canals resembling a network of roads. We recently discovered that most of the bone loss with age occurs from these canals, not from t rabecular bone as currently believed. This suggests to know why and how bone breaks requires the study of the morphology of these canals and how they change with age. This is what we propose to do. It has never been done.
Cellular Responses To Thrombin In Skeletal Pathology
Funder
National Health and Medical Research Council
Funding Amount
$120,775.00
Summary
Many diseases of bones, such as osteoporosis and delayed fracture repair, result from the abnormal function of bone cells. Factors regulating bone cell function are, therefore, important in maintaining a healthy skeleton, as well as in the skeleton's response to disease. The enzyme thrombin is involved in blood coagulation but also causes bone cells to alter their behaviour. Thrombin stimulates proliferation of bone-forming cells and protects them from premature death. Thrombin also stimulates t ....Many diseases of bones, such as osteoporosis and delayed fracture repair, result from the abnormal function of bone cells. Factors regulating bone cell function are, therefore, important in maintaining a healthy skeleton, as well as in the skeleton's response to disease. The enzyme thrombin is involved in blood coagulation but also causes bone cells to alter their behaviour. Thrombin stimulates proliferation of bone-forming cells and protects them from premature death. Thrombin also stimulates the breakdown of bone. We will investigate how thrombin's effects on bone cell behaviour influence the course of bone healing. We will also determine how thrombin stimulates bone breakdown and increases survival of bone-forming cells. This study will contribute to the understanding of how bone cells function in health and disease.Read moreRead less
The Role Of Protease-activated Receptor-2 In Regulation Of Bone Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$216,100.00
Summary
Many diseases of bones, such as osteoporosis and delayed fracture repair, result from the abnormal function of bone cells. Factors regulating bone cell function are, therefore, important in maintaining a healthy skeleton, as well as in the skeleton's response to disease. We have recently demonstrated the presence of a receptor called PAR-2 on bone-forming cells. We have also shown that activation of PAR-2 inhibits the development of bone-resorbing cells (osteoclasts) in response to hormones. We ....Many diseases of bones, such as osteoporosis and delayed fracture repair, result from the abnormal function of bone cells. Factors regulating bone cell function are, therefore, important in maintaining a healthy skeleton, as well as in the skeleton's response to disease. We have recently demonstrated the presence of a receptor called PAR-2 on bone-forming cells. We have also shown that activation of PAR-2 inhibits the development of bone-resorbing cells (osteoclasts) in response to hormones. We plan to investigate the mechanism of this effect, as well as to identify how PAR-2 activation modulates other responses of bone cells to hormones. Molecules that activate PAR-2 are present in bone in certain disease situations, but it is not known what activates PAR-2 in bone under normal conditions. We will identify physiological activators of PAR-2 within bone.Read moreRead less
Osteoporosis is a major health burden resulting from bone fractures in older men and women due to progressive loss of bone and weakening of the skeleton. Although there are currently therapies to reduce bone loss, no current treatment effectively reconstructs lost bone. In this project, which is designed to identify new genes that may in the future be targeted by drugs to reverse osteoporosis, we have identified specific sets of genes that appear to work together to increase bone formation. This ....Osteoporosis is a major health burden resulting from bone fractures in older men and women due to progressive loss of bone and weakening of the skeleton. Although there are currently therapies to reduce bone loss, no current treatment effectively reconstructs lost bone. In this project, which is designed to identify new genes that may in the future be targeted by drugs to reverse osteoporosis, we have identified specific sets of genes that appear to work together to increase bone formation. This proposal is aimed at characterising these genes and the ways in which they work to determine whether they may be good targets for new osteoporosis treatments. We will examine the patterns of these genes in bone. We will also use cell cultures in which bone forming cells develop and function, to determine when the genes are expressed and how they function. We will test the ability of the candidate genes to cause an increase in the amount of bone forming activity in these cell cultures. An increase in bone formation may be caused by an increase in the number bone-forming cells, an increase in the activity of the cells, a decrease in cell death, or a combination of these changes. Each possibility will be tested. This research is important because of the need for new osteoporosis therapies to repair weakened bones. The knowledge resulting from this proposal has the potential to provide an important contribution to skeletal health and thus aged health worldwide.Read moreRead less
Investigation Of COX-2 Regulation Of Bone Turnover And Mechanically Induced Bone Formation By Genetic Overexpression.
Funder
National Health and Medical Research Council
Funding Amount
$440,750.00
Summary
This project is important because it uses novel experimental models to advance our knowledge of prostaglandin biology in normal and pathological bone remodelling, and the response of the skeleton to increased physical activity. We expect that a genetic modification in mice to increase the normal production of key prostaglandin enzymes, cyclooxygenase-2 (COX-2), in bone cells will increase the number of cells that remove bone (osteoclasts), and increase bone loss and the rate of bone turnover whe ....This project is important because it uses novel experimental models to advance our knowledge of prostaglandin biology in normal and pathological bone remodelling, and the response of the skeleton to increased physical activity. We expect that a genetic modification in mice to increase the normal production of key prostaglandin enzymes, cyclooxygenase-2 (COX-2), in bone cells will increase the number of cells that remove bone (osteoclasts), and increase bone loss and the rate of bone turnover when compared to normal mice. We believe this will occur via the effect of prostaglandins on expression of genes that control osteoclast formation. This will be tested by examining the structure of the skeleton, and the expression of certain genes, in transgenic mice at different ages from 2-8 months. These effects may be exacerbated in conditions of increased bone turnover, such as postmenopausal bone loss. This will be tested by examining the bone structure and gene expression in adult mice following removal of their ovaries. Due to the role of COX-2 in adaptation of bone to mechanical loading, we also expect the load-bearing skeleton to be more sensitive to increased weight-bearing activity. We will investigate this hypothesis by applying mechanical loads to the tibiae of mice in a controlled manner and then analysing the bone structure. Knowledge of specific pathways by which bone formation can be stimulated is important for developing novel approaches to induction and augmentation of osteogenesis in skeletal diseases associated with ageing or disability, or for maintenance of new bone around implants. The discovery that COX-2 is a key enzyme in mechanotransduction and osteoclastogenesis in bone, and a pharmacological target for modulating inflammation, has considerable clinical significance. Exploiting this knowledge requires precise knowledge of the role of this enzyme in bone remodelling and adaptation and our experiments will contribute significantly to that knowledgeRead moreRead less
Osteoporosis is a major health burden resulting from bone fractures in older men and women due to progressive loss of bone and weakening of the skeleton. No current treatment effectively reverses this bone loss. Using genetic models in mice, we have identified a pathway, involving the nerve signal molecule NPY, that is capable of inducing large (200 - 300%) increases in bone very rapidly (within a few weeks), in the skeleton of adult mice. This proposal is aimed at characterising this new pathwa ....Osteoporosis is a major health burden resulting from bone fractures in older men and women due to progressive loss of bone and weakening of the skeleton. No current treatment effectively reverses this bone loss. Using genetic models in mice, we have identified a pathway, involving the nerve signal molecule NPY, that is capable of inducing large (200 - 300%) increases in bone very rapidly (within a few weeks), in the skeleton of adult mice. This proposal is aimed at characterising this new pathway to assess its potential to provide new treatments for human osteoporosis. This research is important because of the size, rapidity and inducibility of the effect. Moreover, since it originates in the brain, it represents a quite novel mechanism by which the skeleton is potentially maintained and repaired. The experiments contained in the initial sections of the proposal are designed to assess not only the ability of the NPY-pathway to protect against bone loss but also to examine the possibility of repair to a fragile skeleton. The bone loss models chosen for study represent postmenopausal and age-related osteoporosis, two prevalent and increasingly common conditions in the aging world population. The latter section of the proposal seeks to clarify the mechanism by which the increase in bone formation occurs within the bone. Understanding the working of this pathway will be vital in developing future treatment regimens. This proposal investigates a novel, powerful and rapid pathway for repairing weakened skeletons. The knowledge resulting from this proposal has the potential to provide an important contribution to skeletal health and thus aged health worldwide.Read moreRead less
This project will test the proposal that rising follicle-stimulating hormone (FSH) levels in ageing females directly accelerate reproductive failure and bone loss , major public health issues due to delayed childbearing and our rising ageing population. We have developed a unique mouse model with elevated FSH levels that cause premature female infertility. We will now use this model to determine the direct effects of high FSH upon ovarian and uterine function, as well as bone loss with age.
Efficacy And Safety Of Vertebroplasty For Treatment Of Painful Osteoporotic Spinal Fractures: A Randomised Trial
Funder
National Health and Medical Research Council
Funding Amount
$586,250.00
Summary
Painful spinal or vertebral fractures are a substantial and growing public health problem and are a burden on the health care system. In Australia, 20-25% of women and 15-20% of men over the age of 50 will develop one or more fractures of their spine in their lifetime. Up to a half of these fractures will result in severe pain and disability. While the fractures generally heal within weeks or a few months, some are so painful that they require narcotic pain control, hospitalisation, and-or long- ....Painful spinal or vertebral fractures are a substantial and growing public health problem and are a burden on the health care system. In Australia, 20-25% of women and 15-20% of men over the age of 50 will develop one or more fractures of their spine in their lifetime. Up to a half of these fractures will result in severe pain and disability. While the fractures generally heal within weeks or a few months, some are so painful that they require narcotic pain control, hospitalisation, and-or long-term nursing home care. Other problems include chronic pain, spinal deformities, loss of height and mobility and restricted breathing. Vertebroplasty is a new procedure consisting of injection of a type of 'bone cement' into the vertebrae to mend the break. It is an exciting treatment because for some people, this results in an immediate and sustained improvement in pain. Although rare, complications such as rib fracture, cement leakage and fractures in other vertebrae do occur. One particular concern is that the mechanical changes to the spine caused by the bone cement may cause long-term complications such as an increased risk of future fractures of treated or adjacent vertebrae. So far, there is very little evidence of the efficacy and safety of this new technology. Importantly, it has not been compared with usual medical care for fractures. In medical research it can be difficult to properly evaluate an exciting and 'apparently' effective treatment that doctors and patients demand. The main aim of this project is to determine whether vertebroplasty is an effective and safe treatment compared to usual medical care. We have a unique opportunity to evaluate vertebroplasty through a strong collaborative effort between the 3 centres currently offering this procedure in Melbourne. If vertebroplasty can be demonstrated to be an effective, safe and cost-effective treatment for painful osteoporotic spinal fractures this will be a valuable addition to current treatment options.Read moreRead less
Investigation Of The Genetic Basis Of Insulin Hypersecretion In A Mouse Model Of Pancreatic Islet Failure
Funder
National Health and Medical Research Council
Funding Amount
$406,980.00
Summary
Type 2 diabetes is a chronic disease that is associated with blindness, kidney failure, heart attacks and stroke and these are secondary to high blood sugar levels. Thus, determining the cause of high blood sugar levels in type 2 diabetes will lead to better management of the disease and ease the financial burden on the public health system. High blood sugar in type 2 diabetes results from the inability of the body to secrete enough insulin. Insulin is the main hormone that lowers blood sugar le ....Type 2 diabetes is a chronic disease that is associated with blindness, kidney failure, heart attacks and stroke and these are secondary to high blood sugar levels. Thus, determining the cause of high blood sugar levels in type 2 diabetes will lead to better management of the disease and ease the financial burden on the public health system. High blood sugar in type 2 diabetes results from the inability of the body to secrete enough insulin. Insulin is the main hormone that lowers blood sugar levels and is produced by the pancreas. The reason for reduced insulin secretion in type 2 diabetes is not known. Paradoxically, it has been shown that some people who are at an increased risk of developing diabetes (eg people with obesity or a family history of diabetes) secrete more insulin than normal. It is not clear why this is, but a few studies have suggested that reducing insulin secretion in these circumstances can protect the pancreas and preserve its ability to secrete the appropriate amount of insulin. The DBA-2 is a mouse strain that like humans with type 2 diabetes, its pancreas can also fail to secrete the appropriate amount of insulin and under these circumstances becomes diabetic. Furthermore our laboratory has generated evidence that shows that like people who are at risk of diabetes, DBA-2 mice in fact secrete more insulin prior to becoming diabetic. Whether the cause of this increased insulin secretion is linked to the eventual reduction of secretion is not known. The aim of this study is to identify the gene that causes increased insulin secretion in the DBA-2 mouse. Furthermore, genetically manipulated animals will be produced that contain only this gene to determine its effect on insulin secretion. Should the identification of this gene be related to the eventual failure of the pancreas to secrete enough insulin, then it would provide a target for drug therapy to correct insulin levels and therefore reduce blood sugar levels.Read moreRead less
The Mechanisms Of The Anabolic Actions Of Androgens In Bone.
Funder
National Health and Medical Research Council
Funding Amount
$470,960.00
Summary
Androgens (male sex hormones) are one of the few agents that increase bone formation. Androgens act by binding to a specific protein, the androgen receptor (AR). To understand exactly how androgens increase bone formation, we will study mice in which the AR is inactivated only in bone forming cells at specific stages of their development. Understanding the way in which androgens act on bone to increase size and strength will be of great benefit in the design of new treatments for osteoporosis.