Exploiting The Pharmacokinetic And Pharmacodynamic Properties Of Bile Acid Receptor Agonists To Treat Liver Disease
Funder
National Health and Medical Research Council
Funding Amount
$653,952.00
Summary
We have generated preliminary data suggesting that chemicals made by the liver, called bile acids, act on fat cells to release a hormone called adiponectin. In liver disease adiponectin has favorable effects, including reducing liver inflammation and fibrosis (scarring). By using drugs that mimic the action of bile acids we expect that adiponectin production by fat cells can be increased, creating a new way to treat patients with chronic liver diseases.
The sphincter of Oddi is a valve-like structure, which regulates the flow of bile and pancreatic juice into the gut. The sphincter of Oddi is under complex control involving nerves and hormones. We know that abnormal sphincter of Oddi function (sphincter of Oddi dysfunction) is associated with a number of human diseases including acute pancreatitis. We are able to recognise abnormal sphincter activity, but we do not know what causes it. One possible reason may be that the nerves going to the sph ....The sphincter of Oddi is a valve-like structure, which regulates the flow of bile and pancreatic juice into the gut. The sphincter of Oddi is under complex control involving nerves and hormones. We know that abnormal sphincter of Oddi function (sphincter of Oddi dysfunction) is associated with a number of human diseases including acute pancreatitis. We are able to recognise abnormal sphincter activity, but we do not know what causes it. One possible reason may be that the nerves going to the sphincter along the bile duct (which carries bile from the liver and gallbladder) may be damaged due to the passage of gallstones or during surgery on the bile ducts or gallbladder. We know that the main bile duct is able to sense pressure changes within and communicate this information (via nerves) to the sphincter which inturn alters its activity to relieve the pressure. Where these nerves are located and the chemical messages they use, are unknown. The aim of this project is to gain some of this information. This knowledge may allow us to design different surgical procedures or develop drugs to prevent or manage the abnormal sphincter of Oddi.Read moreRead less
How Does Dietary Cholesterol Induce Non-alcoholic Steatohepatitis?
Funder
National Health and Medical Research Council
Funding Amount
$802,600.00
Summary
Non-alcoholic fatty liver disease is the most common liver disease that can progress to non-alcoholic steatohepatitis (NASH), cirrhosis and liver cancer. Dietary cholesterol is a major risk factor for NASH. We can demonstrate that cholesterol changes the gut bacteria. These bacteria generate toxic chemicals (bile acids) that signal to the liver and induce NASH. In this project, we use novel ways to clarify the mechanisms of liver inflammation and test novel therapeutic approaches to reverse it.
A Novel Metabolic Role For UDP Glycosyltransferase 8 (UGT8)
Funder
National Health and Medical Research Council
Funding Amount
$419,144.00
Summary
The UDP glycosyltransferases (UGTs) are a family of enzymes that remove drugs and toxins from the human body as well as control levels of naturally produced molecules such as bile acids and hormones. We found that a new member of this family called UGT8 processes bile acids in the kidney and intestine and can affect how bile acids act to regulate metabolism. Our studies uncover new roles for bile acids in liver, kidney and gut health and in metabolic disorders such as diabetes and obesity.
The Physiological And Pathological Role Of The Bile Acid Receptor TGR5 And Its Potential Targeting For The Treatment Of Intestinal Motility Disorders And Visceral Pain.
Funder
National Health and Medical Research Council
Funding Amount
$311,860.00
Summary
Defects in the secretion of bile into the intestine cause digestive diseases, and abnormal circulating levels of bile acids induce profound itch and abnormal pain sensation. This project examines whether a cell-surface receptor (TGR5) produced by intestinal and sensory neurons mediates actions of bile acids on intestinal functions and pain. The project aims to define mechanisms of digestive and sensory disorders and identify new therapies for constipation, diarrhoea, and pain.
Bile Acid Detoxification By Nuclear Receptor-mediated CYP3A Regulation
Funder
National Health and Medical Research Council
Funding Amount
$196,527.00
Summary
Liver diseases in which there is obstruction to bile flow (cholestatic liver diseases) can lead to liver failure, liver cirrhosis as well as a diminished quality of life. Patients suffer from severe itching which may prove difficult to control. It is thought that many of these adverse effects of obstructed bile flow are due to the retention of a component of bile, called bile acids, within the body. Bile acids are detergent-like compounds formed from cholesterol. Some bile acids are highly toxic ....Liver diseases in which there is obstruction to bile flow (cholestatic liver diseases) can lead to liver failure, liver cirrhosis as well as a diminished quality of life. Patients suffer from severe itching which may prove difficult to control. It is thought that many of these adverse effects of obstructed bile flow are due to the retention of a component of bile, called bile acids, within the body. Bile acids are detergent-like compounds formed from cholesterol. Some bile acids are highly toxic and cause the death of cells in the liver if their concentration becomes too high. Evidence has emerged that the body has control mechanisms to try and combat rising levels of bile acids in cholestatic liver diseases. One such mechanism, which is the subject of this application, is the metabolism of bile acids to less toxic forms, by a process called hydroxylation. A particular class of liver enzymes, known as cytochromes P450 CYP3As, appear to mediate these hydroxylation reactions. Liver cytochrome P450 enzymes are important to medicine in areas as broad as drug breakdown, steroid hormone regulation and the formation or elimination of cancer causing chemicals. These enzymes are present in high concentration in the human liver, but the factors governing how much of these enzymes are produced have been poorly understood. The present projects builds on discoveries concerning the regulation of cytochrome P450 enzymes made by our group over the last few years, including an in-depth understanding of the way the production of CYP3As are increased by some drugs. We intend to determine the mechanism by which bile acids increase the level of CYP3A enzymes are how effective these enzymes are in hydroxylating bile acids. An understanding of these issues will allow us to better manage patents with cholestatic liver diseases and develop new strategies for treating these diseases, for example, development of novel drugs that increase bile acid hydroxylation in the liver.Read moreRead less