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 Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>