Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mammals Can be Stimulated to Regrow Damaged Inner Retina Nerve Cells

26.11.2008
Researchers at the University of Washington (UW) have reported for the first time that mammals can be stimulated to regrow inner nerve cells in their damaged retinas. Located in the back of the eye, the retina's role in vision is to convert light into nerve impulses to the brain.

The findings on retina self-repair in mammals will be published this week in the Early Edition of the Proceedings of the National Academy of Sciences. Other scientists have shown before that certain retina nerve cells from mice can proliferate in a laboratory dish. Today's report gives evidence that retina cells can be encouraged to regenerate in living mice.

The UW researchers in the laboratory of Dr. Tom Reh, professor of biological structure, studied a particular retinal cell called the Müller glia.

"This type of cell exists in all the retinas of all vertebrates," Reh said, "so the cellular source for regeneration is present in the human retina." He added that further studies of the potential of these cells to regenerate and of methods to re-generate them may lead to new treatments for vision loss from retina-damaging diseases, like macular degeneration.

The researchers pointed out the remarkable ability of cold-blooded vertebrates like fish to regenerate their retinas after damage. Birds, which are warm-blooded, have some limited ability to regenerate retinal nerve cells after exposure to nerve toxins. Fish can generate all types of retinal nerve cells, the researcher said, but chicks produce only a few types of retinal nerve cell replacements, and few, if any, receptors for detecting light.

Müller glia cells generally stop dividing after a baby's eyes pass a certain developmental stage. In both fish and birds, the researchers explained, damage to retinal cells prompts the specialized Müller glia cells to start dividing again and to increase their options by becoming a more general type of cell called a progenitor cell. These progenitor cells can then turn into any of several types of specialized nerve cells.

Compared to birds, the scientist said, mammals have an even more limited Müller glia cell response to injury. In an injured mouse or rat retina, the cells may react and become larger, but few start dividing again.

Because the Müller glia cells appeared to have the potential to regrow but won't do so spontaneously after an injury, several groups of researchers have tried to stimulate them to grow in lab dishes and in lab animals by injecting cell growth factors or factors that re-activate certain genes that were silenced after embryonic development. These studies showed that the Müller glia cells could be artificially stimulated to start dividing again, and some began to show light-detecting receptors. However, these studies, the researchers noted, weren't able to detect any regenerated inner retina nerve cells, except when the Müller glia cells were genetically modified with genes that specifically promote the formation of amacrine cells, which act as intermediaries in transmitting nerve signals.

"This was puzzling," Reh said, "because in chicks amacrine cells are the primary retinal cells that are regenerated after injury." To resolve the discrepancy between what was detected in chicks and not detected in rodents, the Reh laboratory conducted a systematic analysis of the response to injury in the mouse retina, and the effects of specific growth factor stimulation on the proliferation of Müller glia cells.

The researchers injected a substance into the retina to eliminate ganglion cells (a type of nerve cell found near the surface of the retina) and amacrine cells. Then by injecting the eye with epidermal growth factor (EGF), fibroblast growth factor 1 (FGF1) or a combination of FGF1 and insulin, they were able to stimulate the Müller glia cells to re-start their dividing engines and begin to proliferate across the retina.

The proliferating Müller glia cells first transformed into unspecialized cells. The researchers were able to detect this transformation by checking for chemical markers that indicate progenitor cells. Soon some of these general cells changed into amacrine cells. The researchers detected their presence by checking for chemicals produced only by amacrine cells.

Many of the progenitor cells arising from the dividing Müller glia cells, the researchers observed, died within the first week after their production. However, those that managed to turn into amacrine cells survived for at least 30 days.

"It's not clear why this occurs," the researchers wrote, "but some speculate that nerve cells have to make stable connections with other cells to survive."

In addition to Reh, the authors of the research findings, "Stimulation of Neural Regeneration in the Mouse Retina," were Mike O. Karl, Susan Hayes, Branden Nelson, Kristine Tan, and Brian Buckingham, all of the UW Department of Biological Structure. The research was supported by postdoctoral fellowships from the German Research Foundation, ProRetina Travel Grants, National Research Service Awards, and a National Eye Institute grant from the National Institutes of Health.

Leila Gray | Newswise Science News
Further information:
http://www.washington.edu

Further reports about: Cells FGF1 Nerve Researcher Retina amacrine glia cells injury mammals nerve cells progenitor progenitor cells regenerate retinal

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

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 >>>