Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Defective lymphatic vessels identified as a novel cause of adult-onset obesity

20.09.2005


Laboratory model missing one copy of Prox1 gene exhibits abnormal increase in fat accumulation around sites of lymph leakage from defective lymphatic vessels, according to St. Jude



Leaky lymphatic vessels are the leading cause of the adult onset obesity observed in a laboratory model developed by investigators at St. Jude Children’s Research Hospital. The findings suggest that the abnormal leakage of lymph fluid from the ruptured lymphatic vessels stimulates the accumulation of fat, particularly in regions of the body rich in lymphatics, the researchers said. The lymphatic vasculature (system of capillaries and vessels) that drains lymph is essential for the immune response in inflammation, and is the main route for the spreading of metastatic tumors to the lymph nodes.

The St. Jude investigators showed that removal of one of the two copies of the gene Prox1 disrupts normal development of the lymphatic vasculature, leading to leakage of lymph from ruptured lymphatic vessels, and subsequent obesity. Specifically, the researchers found that adipocytes (fat cells) near leaking lymphatic vessels under the skin and in the abdomen were significantly larger than normal, and therefore able to store more lipids (e.g., fatty acids and triglycerides, used as an energy source).


"This is the first such evidence in an in vivo model showing that defects in the integrity of the lymphatic vasculature could lead to adult obesity," said Guillermo Oliver, Ph.D., an associate member of the Genetics and Tumor Cell Biology Department at St. Jude. "And therefore, this is the first model available for studying obesity linked to faulty lymphatic vessels. It will be an important tool for studying this novel form of adult-onset obesity, as well as diseases of lymphatic vessels, and eventually, extending those findings to humans." Oliver is senior author of a report on this work that appears in the September 18 online issue of Nature Genetics.

The laboratory model (Prox1+/- ) lacked one of two copies of the Prox1 gene, which is required for proper development of the lymphatic system. Previously, Oliver’s laboratory reported that Prox1 activity is necessary for the normal development of cells making up the lymphatic vasculature; and that it is the subsequent budding and sprouting of those cells that give rise to the lymphatic system (Cell [98]:769-778; 1999).

Most Prox1+/- heterozygous (i.e., having only one copy of the gene) models die quickly in the postnatal period as a consequence of extensive lymphatic leakage that accumulates in the abdomen and thorax (chest). "However, those with a milder disruption of their lymphatic vasculature were able to survive and become obese with age," Oliver said.

"Interestingly, those that survived did not develop diabetes, as commonly seen in different types of obesity," he added. "This told us that the type of obesity we were seeing in this laboratory model was different from forms of obesity that are commonly associated with diabetes." The researchers also demonstrated that lymph removed from the abdominal cavity of the Prox1+/- models and added to cultured cells can promote adipocyte differentiation, most likely due to certain factors present in the collected lymph.

"Our findings might encourage physicians to consider that at least some of their obese patients might be suffering from a problem that can’t be solved by eating less and exercising more," Oliver said. Just as many vascular disorders arise because of blood vessel defects, other defects of the closely related lymphatic vessels in addition to edema could also occur in humans, he added.

Kelly Perry | EurekAlert!
Further information:
http://www.stjude.org

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

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...

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

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>