Diabetic cardiomyopathy (DiabCM) is common in people with diabetes. It predisposes to heat failure. Its cause remains unclear and there is no specific treatment for DiabCM. Inflammation is a fundamental tissue response to a metabolic insult and it occur in DiabCM. The central hypothesis in this work is that inflammation through myocardial macrophage cells contributes to DiabCM. This hypothesis will be tested in animal models and also in cell culutre studies.
Correction Of Diabetes In An Autoimmune Model Using Insulin-secreting Liver Cells.
Funder
National Health and Medical Research Council
Funding Amount
$472,500.00
Summary
Type I diabetes mellitus is caused by the autoimmune destruction of the beta cells of the pancreas that secrete insulin. The problems of the chronic complications of diabetes and the lack of donor tissue for transplantation, could theoretically be overcome by engineering from the patient's own cells, an artificial beta cell, i. e. a non-islet cell capable of synthesising, storing and secreting mature insulin in response to metabolic stimuli, such as glucose. The ultimate goal of this technology ....Type I diabetes mellitus is caused by the autoimmune destruction of the beta cells of the pancreas that secrete insulin. The problems of the chronic complications of diabetes and the lack of donor tissue for transplantation, could theoretically be overcome by engineering from the patient's own cells, an artificial beta cell, i. e. a non-islet cell capable of synthesising, storing and secreting mature insulin in response to metabolic stimuli, such as glucose. The ultimate goal of this technology is to deliver the insulin gene directly to a patient's own liver cells which would regulate insulin secretion in response to glucose and other substances that stimulate insulin secretion, controlling blood glucose without the need for immunosuppression. To accomplish this it must be possible to deliver the insulin gene efficiently to primary liver cells (cells derived from an animal's or human's body). Results from our laboratory using a non-pathogenic viral delivery system indicate that we can reverse diabetes in chemically induced diabetic rats by expression of insulin and a beta cell transcription factor NeuroD. The aim of this study is to repeat this in an auto-immune model of diabetes the nonobese diabetic mouse, which mimicks very closely the development of diabetes in humans. We will determine if we can reverse diabetes in these animals and determine if their response to glucose is normal over an extended period of time, with no attack by the factors of the immune system that stimulate the development of diabetes in man. The results from this research proposal should result in the delivery of the insulin gene to large numbers of primary liver cells that will then synthesise, store and secrete insulin in response to glucose. These cells would control blood glucose levels in patients without the need for immunosuppression.Read moreRead less
Role And Mechanism Of Connective Tissue Growth Factor In Diabetic Cardiomyopathy
Funder
National Health and Medical Research Council
Funding Amount
$382,820.00
Summary
Diabetic cardiomyopathy is a condition where the heart muscle is directly damaged by diabetes. It is being recognised as a prominent cause of both acute and chronic heart failure in diabetes. It is common and occurs in up to 60% of diabetic patients . At present however, no treatments are available to directly treat the cardiomyopathy. This condition can also occur in people with diabetes who have high blood pressure and-or coronary artery disease and may combine with these problems to worsen pa ....Diabetic cardiomyopathy is a condition where the heart muscle is directly damaged by diabetes. It is being recognised as a prominent cause of both acute and chronic heart failure in diabetes. It is common and occurs in up to 60% of diabetic patients . At present however, no treatments are available to directly treat the cardiomyopathy. This condition can also occur in people with diabetes who have high blood pressure and-or coronary artery disease and may combine with these problems to worsen patient outcomes. We have generated data in experimental diabetes in rodents that strongly implicates a heart growth factor in causing diabetic cardiomyopathy. This protein, called connective tissue growth factor (CTGF), is increased in diabetic cardiomyopathy, and is elevated by high glucose and other factors in diabetes. We have published data showing that CTGF causes tissue scarring like that which occurs in cardiomyopathy, by affecting signals in cells called fibroblasts. It increases the laying down of extracellular matrix (ECM) and also inhibits the degradation of ECM by the proteins that break down matrix, known as the MMPand PAI systems. Such accumulation of ECM is thought to be a major factor leading to abnormal muscle function in cardiomyopathy. We now plan to block CTGF in this diabetic heart model to determine if we can prevent diabetic cardiomyopathy. We have generated two methods to inhibit CTGF in the animal model. Echocardiography (a heart ultrasound test), and molecular analysis of the heart tissue will determine if we can prevent the otherwise adverse functional and structural changes of diabetes in the heart. We will also study our baboon model of diabetes to determine if diabetic cardiomyopathy with increased heart CTGF is present in the primates. Cell culture studies from rat heart fibroblasts and myocytes will determine how CTGF has the effect on cells to cause cardiomyopathy and how we might further prevent this condition developing in diabetes.Read moreRead less
Non-alcoholic steato-hepatitis (NASH) is a common disease of liver inflammation and scarring, which may progress to cirrhosis or liver cancer. While type 2 diabetes causes a higher rate of NASH and more rapid NASH progression the reasons for this are not clear. We have developed a novel animal model of NASH with diabetes added to dietary induced obesity. We show that a growth factor is elevated in the affected livers. We plan to block the growth factor to see if we can prevent NASH worsening.