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 Modern genetic sequencing tools give clearer picture of how corals are related
17.08.2017 | University of Washington

nachricht The irresistible fragrance of dying vinegar flies
16.08.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

NASA Protects its super heroes from space weather

17.08.2017 | Physics and Astronomy

Spray-on electric rainbows: Making safer electrochromic inks

17.08.2017 | Materials Sciences

Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

17.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>