Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Brain stem cells are not rejected when transplanted

14.07.2003


Findings could improve retinal and other nervous system transplants



For the first time scientists have shown that brain stem cells are immune privileged, which means that they are invisible to a transplant recipient’s immune system and do not trigger the immune system to reject them. These results, published in the July issue of Stem Cells, indicate that using central nervous system stem cells in transplants for diseases of the eye (which is part of the brain), brain, and spinal cord, may eliminate the need for tissue typing before, and immunosuppressive drugs after, transplantation. Ultimately these findings promise to improve the success of retinal transplantation to regenerate vision for millions with macular degeneration, retinitis pigmentosa and diabetic retinopathy and brain transplants to restore functioning for patients with disorders such as Parkinson’s disease.

"These findings are very exciting," says Michael Young, PhD, the lead author of the study and an assistant scientist at Schepens Eye Research Institute and assistant professor at Harvard Medical School. "Though we suspected brain stem cells might be protected in this way, this is the first documented evidence."


Most tissues when transplanted from one body to another are seen by the recipient as foreign and attacked by the immune system. This is because the transplanted tissue has molecules on its surface called antigens that are recognized by the immune system as "not self." If the immune response goes unchecked by drugs to inhibit the attack, it will eventually destroy the transplanted tissue and reject it.

There are sites in the body that do not mount attacks against foreign tissue because to do so would be too self-destructive. For instance, in the eye an all out immune attack would cause inflammation that would destroy delicate tissue and, with it, vision. These sites, which are known as "immune privileged," include the eye, the brain, the digestive system, and the reproductive system.

Young, who in previous research found that brain and retinal stem cells transplanted into the eyes of mice and rats seemed to survive longer and integrate more easily into damaged retinas than other cells, suspected that these "neural stem cells" might be immune privileged. The only way for him to learn the true nature of their immune properties was to transplant these neural stem cells to a part of the recipients body that, unlike the eye, was not immune privileged already.

He and his colleagues chose a part of the body that always rejects transplanted tissue without immunosuppressant drugs and without close tissue typing – the kidney capsule, the pouch in which the kidney is located. This pouch is commonly used to determine whether transplants can survive. Over the years scientists have tested skin, cornea and other tissues in the kidney capsule to evaluate their transplant potential.

Young and his colleagues took brain stem cells from green mice (mice in which the gene for green protein found in jellyfish has been inserted) and placed them under the kidney capsule in other normal non-green mice. After 4 weeks, the team examined the mice and found that the stem cells had not been rejected in any of the mice, and, in fact, had grown into neural tissue.

They concluded that these neural stems cells did not induce an immune response and must be invisible to the immune system, at least initially. The next step was to determine if the cells possessed the antigens that most other tissues had. To test this theory, the team took other brain cells (not stem cells) from the green mice and implanted them in the normal non-green mice. These cells were rejected, and when brain stem cells were then again implanted in the normal non-green mice, they, too were rejected. The team concluded, therefore, that the brain stem cells did possess antigens, but unless the recipient was primed or pre-immunized, the antigens were not visible to the immune system of the recipient and not rejected.

"Understanding the immune properties of these stem cells could have an enormous effect on how we perform brain or retinal transplantations in the future. Stem cells already have the advantage of being able to transform or differentiate into various types of cells and can be reproduced endlessly outside the body. Now we know that at least brain stem cells are immune privileged and can be used without the same worry about tissue matching or immunosuppression that is true for other types of tissue. Young is the director of Schepens Eye Research Institute’s Minda de Gunzburg Retinal Transplantation Research Center. The center is committed, with a focus on retinal regeneration, to unlocking the mysteries of vision and finding the cures for blinding eye diseases that devastate millions in the United States and around the world.

The study, titled "Neural progenitor cells lack immunogenicity and resist destruction as allografts" can be obtained at the Stems Cells website at http://stemcells.alphamedpress.org/ or by emailing pattijacobs@hotmail.com or mikey@vision.eri.harvard.edu.

Other members of the research team include Junko Hori, Tat Fong Ng, Marie Shatos, and J. Wayne Streilein of Schepens Eye Research Institute of Boston and Henry Klassen of the Stem Cell Research Program at Children’s Hospital of Orange County in Orange, California.


###
Schepens Eye Research Institute is an affiliate of Harvard Medical School and is the largest independent eye research institute in the world.


Patti Jacobs | EurekAlert!
Further information:
http://www.eri.harvard.edu/
http://stemcells.alphamedpress.org/

More articles from Life Sciences:

nachricht The first genome of a coral reef fish
29.09.2016 | King Abdullah University of Science and Technology

nachricht New switch decides between genome repair and death of cells
27.09.2016 | University of Cologne - Universität zu Köln

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New welding process joins dissimilar sheets better

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.

Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

European Health Forum Gastein 2016 kicks off today

28.09.2016 | Event News

Laser use for neurosurgery and biofabrication - LaserForum 2016 focuses on medical technology

27.09.2016 | Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

 
Latest News

The first genome of a coral reef fish

29.09.2016 | Life Sciences

Gentle sensors for diagnosing brain disorders

29.09.2016 | Medical Engineering

Swiss space research reaches for the sky

29.09.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>