Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Surprising findings about Hepatitis C and insulin resistance

10.03.2010
We have known for several years that Hepatitis C, a common cause of liver cirrhosis and cancer, also makes people three to four times more likely to develop Type 2 diabetes.

In studying the insulin resistance of 29 people with Hepatitis C, Australian researchers have confirmed that they have high insulin resistance, a precursor to diabetes. However, almost all insulin resistance occurs in muscle, with little or none in the liver, a very surprising finding given that Hepatitis C is a liver disease.

Dr Kerry Lee Milner and Professor Don Chisholm from Sydney’s Garvan Institute of Medical Research, in collaboration with Professor Jacob George from the Storr Liver Unit, University of Sydney at Westmead Hospital, have published their study in the prestigious international journal, Gastroenterology, now online.

Insulin, a hormone made by the pancreas, helps the body use glucose for energy. The two most important organs that respond to insulin are the liver and muscle. A healthy liver responds to insulin by not producing glucose, while healthy muscle responds by using glucose. An insulin resistant liver produces unwanted glucose, while insulin resistant muscle cannot absorb it from the bloodstream, leading to high levels of sugar in the blood.

“Contrary to all expectations, not only did we find no significant insulin resistance in the liver of the patients in the study, half of them suffered from a strain of Hepatitis C that causes about three times the normal level of fat to accumulate in the liver,” said Professor Chisholm.

“The fifteen people with very high levels of fat in the liver had the same degree of insulin resistance as the fourteen that didn’t have fatty livers.”

“A number of important investigators around the world have been arguing that fat in the liver is an extremely important determinant of insulin resistance, perhaps the most important. At least in this context, we’ve shown that not to be the case.”

“Before you get Type 2 diabetes, you must become insulin resistant and your insulin producing cells must also fail to compensate. Insulin resistance alone will not give you diabetes.”

“In our study, we gave intravenous glucose, a specific stimulus to insulin secretion, and showed that insulin secretion was not impaired in Hepatitis C patients compared to our control group.”

“This finding tells us that people with Hepatitis C who develop diabetes probably have susceptible insulin-producing cells, and would probably get it anyway – but much later in life. The extra insulin resistance caused by Hepatitis C apparently brings on diabetes at 35 or 40, instead of 65 or 70.”

“More work now needs to be done into why Hepatitis C causes insulin resistance in muscle. That will give us better insight into the behaviour of the disease.”

“At this stage, it is helpful for people with Hepatitis C to understand insulin resistance and what it can mean for them. If they have relatives with Type 2 diabetes, they will be genetically prone to developing it themselves and so would be advised to manage their diets very carefully and take plenty of exercise – to slow onset.”

Notes to Editors

Hepatitis C is a blood-borne virus and in Australia is caused mainly by drug users sharing needles, but also by unsterile tattooing or body piercing. There is no vaccine for Hepatitis C, unlike Hepatitis A and B.

Around 212,000 Australians suffer from chronic Hepatitis C, 80,000 - 85,000 of them in NSW. Across Australia, there are roughly 10,000 new infections each year.

There are 6 strains of Hepatitis C – the participants in this study were selected because they had either of two common strains in Australia, Genotype 1 and Genotype 3. The latter strain causes significant fat deposits in the liver.

While it is not noted in the media release above, the study observed that the degree of insulin resistance is a negative predictor of anti-viral treatment. In other words, the greater the insulin resistance, the less responsive people will be to treatment.

Between 50-80% of people who are treated for Hepatitis C are successfully treated, leaving 20-50% who do not respond. Treating with lifestyle changes or an insulin sensitiser may reduce this percentage - as well as delaying onset of diabetes.

The study found that predictors of insulin resistance were viral load and subcutaneous fat. This suggests the possibility that the virus alters either fat supply or alters the cell signalling proteins released from subcutaneous fat, either of which could generate insulin resistance.

ABOUT GARVAN
The Garvan Institute of Medical Research was founded in 1963. Initially a research department of St Vincent's Hospital in Sydney, it is now one of Australia's largest medical research institutions with nearly 500 scientists, students and support staff. Garvan’s main research programs are: Cancer, Diabetes & Obesity, Immunology and Inflammation, Osteoporosis and Bone Biology, and Neuroscience. The Garvan’s mission is to make significant contributions to medical science that will change the directions of science and medicine and have major impacts on human health. The outcome of Garvan’s discoveries is the development of better methods of diagnosis, treatment, and ultimately, prevention of disease.
MEDIA ENQUIRIES
Alison Heather
Science Communications Manager
Garvan Institute of Medical Research
+61 2 9295 8128
+61 434 071 326
a.heather “at” garvan.org.au

Alison Heather | EurekAlert!
Further information:
http://www.garvan.org.au
http://www.researchaustralia.org

More articles from Life Sciences:

nachricht Staying in Shape
16.08.2018 | Max-Planck-Institut für molekulare Zellbiologie und Genetik

nachricht Chips, light and coding moves the front line in beating bacteria
16.08.2018 | Okinawa Institute of Science and Technology (OIST) Graduate University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Staying in Shape

16.08.2018 | Life Sciences

Diving robots find Antarctic seas exhale surprising amounts of carbon dioxide in winter

16.08.2018 | Earth Sciences

Protein droplets keep neurons at the ready and immune system in balance

16.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>