Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Circulating fats kill transplanted pancreas cells, study shows

29.08.2007
Dietary restrictions or other strategies that limit fat formation might make pancreatic cell transplants more effective, UT Southwestern Medical Center researchers report.

Using animal models, the researchers discovered that pancreatic islet cells transplanted into the liver fail not only because of immune rejection, but also because of overexposure to toxic fats that are synthesized by the surrounding liver cells and flood the pancreatic transplants. Their findings appear in the September issue of the journal Diabetes.

To date, a few hundred people have received transplants of complexes of pancreatic cells, called islets. The islets are implanted in the liver, where they at first make insulin, but over months or years their production often declines.

“By understanding how fat affects these cells, maybe we can improve islet transplant and make it last a bit longer,” said Dr. Roger Unger, professor of internal medicine at UT Southwestern and senior author of the study.

During islet transplantation, the pancreatic cell complexes are injected into a large vein that feeds into the liver, where they lodge. Cells within the islets, called beta cells, then produce insulin. The person receiving the transplant must take anti-rejection drugs.

Dr. Unger said that after two years, 87 percent of recipients must resume taking insulin, a problem that has led clinicians to investigate if the anti-rejection drugs are at fault, or if some other mechanism is at work.

In the current study, UT Southwestern researchers tested the hypothesis that fats in the liver might be killing the beta cells. The liver receives its blood supply directly from the digestive system, which provides a rich concentration of fats and sugars to the transplanted islet cells – conditions the cells would not be exposed to in their normal environment in the pancreas. The researchers also theorized that the insulin that each islet produced might stimulate fat production around itself, adding to the problem.

The researchers first injected rats with a drug that kills pancreatic beta cells in order to mimic human insulin-dependent, or juvenile, diabetes (type 1), a condition in which beta cells are unable to produce insulin. They then transplanted beta cells into the animals’ livers. Fat accumulations were found around islets four weeks after transplantation. Insulin levels declined, and the animals died at 15 weeks.

Another group of similar rats was then exposed to one of two conditions that reduce body fat – a restricted diet or administration of leptin, a hormone that decreases appetite and increases metabolism. In both cases, more beta cells survived. Rats that had received leptin also showed the highest survival rate of beta cells.

Because the differences among the groups of rats could be traced to the amount of fat, and no anti-rejection drugs had been given, the results validate their theory that fat was the culprit in killing the beta cells, Dr. Unger said.

These results also suggest that diet and weight control might enable transplanted beta cells in humans to survive longer or avoid destruction, he said.

“This seems very easy to prevent, but it’s not being targeted by researchers,” he said.

Dr. Unger said the study could also serve as a model for death of beta cells in non-insulin-dependent, or adult-onset, diabetes (type 2), a condition that is associated largely with obesity. His group is now working with other researchers at UT Southwestern to determine if excess fat is killing cells in obese humans.

Aline McKenzie | EurekAlert!
Further information:
http://www.utsouthwestern.edu

More articles from Studies and Analyses:

nachricht Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>