The Role Of The Adiponectin Receptors In Liver Fibrosis
Funder
National Health and Medical Research Council
Funding Amount
$393,159.00
Summary
Advanced liver scarring (fibrosis) contributes to the death of 1500 Australians annually. Two-thirds of our community is overweight or obese, and this worsens liver disease. A protein secreted by fat, adiponectin, may be important as it acts on liver cells to promote fibrosis. To understand adiponectins role, we will use mice null for adiponectin receptor genes and study its action on liver cells. This study will improve our understanding of liver scarring biology and patient treatments.
Overweight individuals have an increased risk for developing liver cancer. This may be due to the reduced production of the fat-derived hormone adiponectin. Reduced levels of adiponectin are associated with increased inflammation and liver disease. Using mice not expressing adiponectin we will test its importance in liver cancer growth. The proposed research will provide a better understanding of the factors that promote liver cancer formation.
Adiponectin: Key Factors Determining Its Metabolic Actions And Influences On Insulin Sensitivity
Funder
National Health and Medical Research Council
Funding Amount
$604,793.00
Summary
Diabetes and obesity are growing at alarming rates due to poor lifestyle and other factors. Adiponectin is a complex molecule secreted by fat tissue that may help to burn fat in other tissues such as muscle and liver. We investigate what are the main determinants of adiponectin action and how these might counteract defective insulin action caused by excessive fat intake. This promises to provide new therapeutic targets to lessen the metabolic derangement associated with diabetes and obesity
MECHANISMS OF DISORDERED HEPATIC LIPID PARTITIONING IN NON-ALCOHOLIC STEATOHEPATITIS
Funder
National Health and Medical Research Council
Funding Amount
$449,591.00
Summary
Fatty liver is the commonest form of liver disease. It is strongly associated with obesity and maturity onset diabetes. The majority of cases of fatty liver disease cause no complications, but when inflammation and liver damage also occur, in the condition of non-alcoholic steatohepatitis or NASH, liver scarring and eventually cirrhosis or liver cancer can result. The reason why some people with fatty liver disease develop NASH and others do not (benign or simple steatosis) is unknown and is the ....Fatty liver is the commonest form of liver disease. It is strongly associated with obesity and maturity onset diabetes. The majority of cases of fatty liver disease cause no complications, but when inflammation and liver damage also occur, in the condition of non-alcoholic steatohepatitis or NASH, liver scarring and eventually cirrhosis or liver cancer can result. The reason why some people with fatty liver disease develop NASH and others do not (benign or simple steatosis) is unknown and is the subject of this research. The studies will be performed in a novel mouse model of obesity and diabetes, the fat aussie mouse, in which all animals develop fatty liver disease after a few months. When fat aussie mice are fed a Macdonald's diet [high in saturated fat] they develop full-blown NASH with liver scarring. Before NASH develops in fat aussie mice, blood levels of adiponectin (a protein produced from fat storage cells) fall. Together with high blood insulin and high blood sugar levels, it is proposed that these changes are what leads to an extraordinarily high build up of fat (lipid) molecules in the liver, to the extent that the fat ultimately damages the liver in a process called lipotoxicity. The planned research will first test whether this hypothesis is correct, and then set about ways to prevent or reverse such a dangerous build up of fats in the liver. Strategies include a high olive oil diet (which is protective in another model of steatohepatitis), correction of blood adiponectin levels, lowering of insulin and blood sugar levels. The anticipated results are a much better understanding of how complications come about in fatty liver disease, and therefore insights into how this disorder can be prevented or reversed in those who are predisposed.Read moreRead less
Mechanisms Of The Insulin-sensitising Effects Of AMPK Activation In Liver And Muscle.
Funder
National Health and Medical Research Council
Funding Amount
$454,500.00
Summary
Type 2 diabetes represents an escalating global health problem. In Australia 7.5% of the population has diabetes and another 16% insulin resistance (impaired action of insulin). Insulin resistance is closely associated with obesity, dyslipidemia, hypertension and cardiovascular diseases (Syndrome X) as well as diabetes. A high caloric intake (particularly with a high fat content) and a sedentary lifestyle are extremely important environmental contributors to Syndrome X and diabetes. One of the m ....Type 2 diabetes represents an escalating global health problem. In Australia 7.5% of the population has diabetes and another 16% insulin resistance (impaired action of insulin). Insulin resistance is closely associated with obesity, dyslipidemia, hypertension and cardiovascular diseases (Syndrome X) as well as diabetes. A high caloric intake (particularly with a high fat content) and a sedentary lifestyle are extremely important environmental contributors to Syndrome X and diabetes. One of the most exciting developments in the past few years has been the discovery that an enzyme, AMP kinase (AMPK), normally activated by exercise, may be involved in its beneficial effects. We have contributed to this exciting field by showing in an animal model that one dose of AICAR, a chemical agent which can activate AMPK, ameliorates the effects of insulin resistance in muscle and liver. Further very recent work has linked AMPK with various drugs (particularly glitazones and metformin) and hormones which can enhance insulin sensitivity. The goal of the experiments in this project is to determine the overall mechanism by which AMPK has ameliorating effects on counteracting insulin resistance. We hypothesize that the mechanism for this involves an effect of AMPK to reduce fat molecules accumulating within muscle and liver cells, and our studies will examine this hypothesis. Our studies should lead to a better understanding of how exercise and pharmacological activators of AMPK help in management of diabetes and insulin resistant states. In addition because AMPK activation enhances glucose metabolism by a separate pathway to insulin, it offers promise of developing compounds able to bypass metabolic steps impaired by insulin resistance. Our studies should help in the design of new therapeutic agents which can counteract insulin resistance.Read moreRead less