Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

MSU researchers make new discoveries on what does and doesn't affect immune system

06.02.2008
Scientists know that a number of factors can affect the body's immune system: poor diet, certain steroids, chronic stress. Now researchers at Michigan State University have discovered that an appetite-controlling hormone also affects the immune system, while natural versions of certain steroids do not.

Both studies are reported in this week's online edition of the Proceedings of the National Academy of Sciences.

"These two studies, while not directly related, show that the neuroendocrine system plays a big role in both the immune system and obesity," said Pamela Fraker, MSU professor of biochemistry and molecular biology and lead scientist for both projects. "MSU is one of the few places studying the relationship between metabolism, the immune system and the neuroendocrine system."

A new role for leptin

One MSU research team discovered that leptin, a hormone produced by fat cells, supports white blood cell production in the body, enhancing immune function. This is the first time leptin's effect on the immune system has been demonstrated.

Scientists have long known that leptin helps control how much a person eats as well as how quickly the body burns energy.

"Many investigators have been trying to unlock the key to obesity for years," said Fraker. "The more fat a person has, the more leptin there is in the bloodstream. In obese people, it seems that the body becomes leptin-resistant -- the signals get jammed. So giving obese people leptin doesn't help them lose weight."

The MSU scientists were examining ob/ob mice (genetically programmed to have non-functional leptin) and db/db mice (genetically programmed to have non-functional leptin receptors), giving them supplemental leptin to study its effects. While causing the mice to eat less, the big surprise was leptin's effect on the immune system. The mice that were given leptin had double the number of B cells, a type of white blood cell produced in bone marrow that fights infection by making antibodies.

"This is a brand new role for leptin," said Fraker. "It appears that most obese people may be somewhat immunosuppressed. This finding shows us that the body's resistance to leptin plays a role in that, too."

To further study leptin's effect on the immune system, Fraker and her colleagues are planning a study on morbidly obese people who will be having gastric bypass surgery. While the outcome of the surgery is highly successful for most people, mortality rates can range from 2 to 10 percent, which is significant.

"Infection from poor wound healing, which is the result of reduced immune function, is one reason people die from the surgery," Fraker said. "We're going to measure people's immune function before and after surgery to see how much it improves, as well as how fast it improves."

Other members of this research team are MSU scientists Louis King, research assistant professor of biochemistry and molecular biology, and Kate Claycombe, assistant professor of food science and human nutrition.

Naturally-produced steroids don't inhibit immune system

While corticosteroids, such as prednisone, reduce inflammation, they also inhibit the body's immune system -- a person taking prescription steroids is more susceptible to infection. Another MSU research team found that corticosteroids produced naturally in the body don't have this same immunosuppressive effect.

The human body secretes corticosteroids when it's under stress, both psychological and physical, and these steroids are responsible for the "fight-or-flight response" in humans and other animals. Cortisol (also called hydrocortisone) is the most abundant corticosteroid in the body. These steroids' anti-inflammatory effects are well-known and pharmaceutical companies have been making versions of them for about 20 years. But people taking steroids are warned that cuts and bruises may be slow to heal because of steroids' effects on the immune system.

Fraker and her team's discovery that the naturally-produced versions of the steroids don't affect the immune system like the pharmacological versions is the first time this has been observed.

"With the pharmacological versions of steroids, you lose some immune function," Fraker explained. "With the natural versions, you retain neutrophil [a type of white blood cell] function. It may be worthwhile for pharmaceutical companies to investigate synthesizing natural versions of the steroids."

Pam Fraker | EurekAlert!
Further information:
http://www.msu.edu

More articles from Health and Medicine:

nachricht On track to heal leukaemia
18.01.2017 | Universitätsspital Bern

nachricht Penn vet research identifies new target for taming Ebola
12.01.2017 | University of Pennsylvania

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: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

How gut bacteria can make us ill

18.01.2017 | Life Sciences

On track to heal leukaemia

18.01.2017 | Health and Medicine

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>