Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Why obesity surgery helps in diabetes

03.09.2008
To manage obesity, various different surgical procedures can be performed on the stomach, including so-called bypass surgery in which, as well as reducing the size of the stomach, a bypass is created to send food directly into the distal gut (which, before the operation, is far from the stomach).

In obese patients who also suffer from diabetes, spectacular improvement in the diabetes is routinely observed following this type of operation although the mechanism underlying this phenomenon was not understood.

Now, experiments conducted in mice by scientists from Université Claude Bernard – Lyon 1, Inserm, CNRS, INRA and the Hôpital Bichat in Paris, have elucidated the mechanism in question. The bypass stimulates glucose synthesis in the gut, an effect that is sustained between meals. Detection of this glucose induces the sending of a signal to the brain which leads to enhanced responsiveness to insulin. These findings—which are reported in the September issue of the journal Cell Metabolism—could point to novel therapeutic approaches in both obesity and diabetes.

In obese patients, the main objective of gastric surgery is to reduce the size of the stomach and this is most commonly achieved by implanting a gastric ring. When the patient also suffers from diabetes, the latter condition tends to improve once he or she has lost some weight. Bypass surgery however has a specific effect in that dramatic improvement is obtained almost immediately—as of discharge of the patient from hospital—a phenomenon which has been hitherto poorly understood. In this form of surgery, as well as reducing the size of the stomach, a bypass is created to send food directly into the distal intestine (which, before the operation, is far from the stomach). The proximal intestine (which is physiologically located immediately after the stomach) is left in place but it no longer receives any food.

Fabrizio Andréelli and his team (Inserm Unit 695, Hôpital Bichat, Paris) have developed models of "ring" and "bypass" surgery in mice in order to elucidate the specific effects of the two techniques.

It was already known that, in the gut (specifically in the wall of the portal vein*), there is a nerve-based system capable of detecting glucose and sending this information to the brain. In 2005, Gilles Mithieux (Inserm Unit 855, Université Lyon 1, INRA–USC 2028) showed that when de novo glucose synthesis is triggered in the intestine (in a process called neoglucogenesis), this signalling system is activated. The sending of the message results in attenuation of feelings of hunger and also has a beneficial effect on blood glucose regulation.

* the portal vein collects blood coming from the gut
Now, the teams of Fabrizio Andréelli and Gilles Mithieux, in collaboration with those of Christophe Magnan (CNRS UMR 7059, Paris 7) and Bernard Thorens (Lausanne), have tested the hypothesis that intestinal neoglucogenesis is involved in the observed, specific effects of gastric bypass surgery. They fed mice a diet rich in lipids and carbohydrates (sugar) to mimic metabolic conditions in diabetic obesity.

The scientists observed strong expression of genes involved in glucose synthesis throughout the guts of the "bypass" mice but not "ring" mice. They also observed that, between meals, glucose was still being released into the portal vein after the ingested food had been absorbed. Enough glucose was being released to trigger the portal vein signalling system, thereby leading to a reduction in the amount of food eaten and dramatic improvement in the ability of insulin to bring the blood glucose concentration down.

These findings shed light on why gastric bypass surgery induces such rapid improvement in diabetes, a phenomenon which was hitherto unexplained.

According to the authors, "These results could point to new therapeutic strategies—surgery or drugs—relevant not only to obesity but also to diabetes".

Séverine Ciancia | alfa
Further information:
http://www.inserm.fr
http://www.cellmetabolism.org/

More articles from Health and Medicine:

nachricht Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>