Mechanisms Of Repair And Adaptation In The Gastric Mucosa: Roles Of COX-2 And Growth Factors
Funder
National Health and Medical Research Council
Funding Amount
$391,650.00
Summary
The stomach lining is continually threatened by its own acid and by hazards such as bacteria and ingested drugs. The drugs called COX inhibitors, which include aspirin, are widely used for treating arthritis and other inflammatory diseases and for preventing heart attacks and strokes. Despite their value in these conditions, COX inhibitors are responsible for about 5-10,000 hospital admissions annually in Australia due to complications from the side effect of stomach ulcers. A recent advance has ....The stomach lining is continually threatened by its own acid and by hazards such as bacteria and ingested drugs. The drugs called COX inhibitors, which include aspirin, are widely used for treating arthritis and other inflammatory diseases and for preventing heart attacks and strokes. Despite their value in these conditions, COX inhibitors are responsible for about 5-10,000 hospital admissions annually in Australia due to complications from the side effect of stomach ulcers. A recent advance has been the development of a sub-class called COX-2 inhibitors. In a very short time, one of these has become among the most prescribed drugs in Australia. The advantage of the COX-2 inhibitors is that they produce many less stomach ulcers. However, they have only been tested in patients who have not had a recent history of ulcer. Our preliminary experiments, together with some related information from two overseas groups, suggests that COX-2 is useful in the stomach, and is markedly increased around a healing ulcer. Our data suggest that blocking it delays the healing of experimental ulcers. This project aims to understand the roles of COX-2 in the stomach, and to clarify the effects of inhibiting it when the stomach is damaged or threatened. The project will also look for links between COX-2's functions and another protective process we have discovered called 'adaptation'. When anti-inflammatory drugs are given regularly to rats or humans under certain conditions, the stomach develops resistance after a few days so that the damage caused by each subsequent dose is markedly reduced. We have uncovered a number of mechanisms responsible for this during a current NH and MRC grant, and plan to explore some of the leads this work has given. The SIGNIFICANCE of the project is its potential to lead to safer use of anti-inflammatory drugs or eventually to new agents, and its potential to give new knowledge about how the lining of organs such as the stomach protects itself.Read moreRead less
COX-2 INHIBITORS AS A CAUSE OF HEART AND RENAL FAILURE
Funder
National Health and Medical Research Council
Funding Amount
$271,610.00
Summary
Non-steroid anti-inflammatory drugs (NSAIDs) have pain-killing and anti-inflammatory properties. For many years Australia had a higher use of these drugs than other countries. The drugs are quite toxic, and in susceptible individuals may cause ulceration and bleeding from the stomach and duodenum, kidney damage and fluid congestion leading to heart failure. Each of these conditions carries a high morbidity, particularly in the elderly. Because of concerns about toxicity, the use of NSAIDs in Aus ....Non-steroid anti-inflammatory drugs (NSAIDs) have pain-killing and anti-inflammatory properties. For many years Australia had a higher use of these drugs than other countries. The drugs are quite toxic, and in susceptible individuals may cause ulceration and bleeding from the stomach and duodenum, kidney damage and fluid congestion leading to heart failure. Each of these conditions carries a high morbidity, particularly in the elderly. Because of concerns about toxicity, the use of NSAIDs in Australia fell during the 1990s by around 40%. Newer allegedly safer forms of NSAIDs called COX-2 inhibitors have been introduced into the Australian market. The first 2 drugs to be marketed are called Celebrex and Vioxx. These drugs appear to be safer for the stomach and duodenum, but the true effects on the kidney and heart are as yet unclear. COX-2 inhibitors have been very widely used with over 1.7 million prescriptions issued since their listing on the Pharmaceutical Benefits Scheme in August 2000. Most of this use appears to be in addition to prescribing of the older NSAIDs rather than as a replacement for them. The purpose of this study is to compare the safety of the new COX-2 inhibitors with that of the older NSAIDs. We are interested in how often they cause renal failure and heart failure. The investigators will use well-established research methods to estimate the risk of heart failure and kidney failure with these drugs in the Australian community. Data from the study will form the basis of clinical practice guidelines for the safe use of these drugs in Australia.Read moreRead less
Short-term Effects Of Overfeeding On Metabolic Risk In Humans
Funder
National Health and Medical Research Council
Funding Amount
$417,196.00
Summary
The prevalence of obesity is rapidly increasing in Australia and other parts of the world. Obesity is closely associated with insulin resistance and plays a role in the development of type 2 diabetes. However, the effects of short-term periods of over nutrition in humans remain unclear. In the proposed study, we will investigate the effects of short-term weight gain by high fat feeding in lean subjects, in subjects who are overweight and in subjects who are genetically more likely to develop dia ....The prevalence of obesity is rapidly increasing in Australia and other parts of the world. Obesity is closely associated with insulin resistance and plays a role in the development of type 2 diabetes. However, the effects of short-term periods of over nutrition in humans remain unclear. In the proposed study, we will investigate the effects of short-term weight gain by high fat feeding in lean subjects, in subjects who are overweight and in subjects who are genetically more likely to develop diabetes (due to strong family history). The aims are to distinguish physiological and endocrine characteristics of individuals who store more fat in response to overfeeding. We will identify differences between these individuals and whether they have defects in upregulating machinery involved in fat oxidation and energy production in skeletal muscle that may help them adapt during to energy excess. We will look for changes in type 2 diabetes risk and we will have the potential to identify defects in factors that are involved in this response. We will also re-examine indivudals again after calorie restriction and weight loss. We also plan to confirm the role of the candidate genes involved in fat oxidation that have been identifieid in human studies by in vivo gene transfer technology in rodents. This study will determine whether overweight and lean subjects behave similarly when faced with an overfeeding challenge. We expect that individuals with a genetic predisposition for T2DM will become more IR, due to metabolic inflexibility and a decreased ability to upregulate machinery involved in fatty acid oxidation and mitochondrial function. By characterising the physiological and endocrine responses to overfeeding, we will establish quantifiable markers allowing us to distinguish those at risk and identify new targets for pharmacological or lifestyle intervention.Read moreRead less
Does Loss Of Melanocortin Glucose Sensing Contribute To Obesity Induced Diabetes?
Funder
National Health and Medical Research Council
Funding Amount
$617,531.00
Summary
Diabetes is a failure to properly regulate blood glucose levels. Escalating rates of diabetes are a major health problem. Melanocortin neurons in the brain detect blood sugar levels and usually regulate glucose production and utilization, but in obese animals they do not. We have developed a possible therapeutic, which appears to reverse the glucose insensitivity, and rapidly reduces blood glucose in diabetic mice. This project will determine how melanocortins act to regulate glucose levels