Getting On Your Nerves ... And Repairing Them 16 February 2007
In a study to be published in the March 2007 issue of The FASEB Journal, scientists from East Carolina University report that a key molecular mechanism, RNA interference (RNAi), plays a role in the regeneration and repair of periphery nerves, which are the nerves located outside of the brain and spinal column. This research may lead to new therapies that manipulate RNAi to treat people with damaged nerves resulting from degenerative disorders and injury.
Andrew Z. Fire of Stanford University and Craig C. Mello of the University of Massachusetts won the 2006 Nobel Prize for the discovery of RNAi. This study builds on this and other RNAi research, which was reviewed in the July 2006 issue of The FASEB Journal, showing that RNAi regulates the creation of proteins in the body. Until now, there has been no direct evidence that RNAi controls local protein synthesis in axonal nerve fibers, which act as "pavement" for the nervous system's "information superhighway." In addition, the mechanism involved in the nerve fiber creation did not depend on communication with, or transport from, the nerve cell body or its nucleus, or from surrounding support cells. Axonal nerve fibers can be as long as three feet (sciatic nerve), and this independence makes RNAi a promising drug target.
"Repairing and rebuilding damaged nerve tissue is one of the greatest medical advances not yet achieved," said Gerald Weissmann, MD, Editor-in-Chief of The FASEB Journal, "and this research is a huge leap forward. It's no accident that a Nobel Prize discovery should be followed up by great new science."
The FASEB Journal is published by the Federation of American Societies for Experimental Biology (FASEB) and is consistently ranked among the top three biology journals worldwide by the Institute for Scientific Information. FASEB comprises 21 nonprofit societies with more than 80,000 members, making it the largest coalition of biomedical research associations in the United States. FASEB advances biological science through collaborative advocacy for research policies that promote scientific progress and education and lead to improvements in human health.
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Brain creates 'new' nerve cells 16 February 2007
Researchers have discovered a type of brain cell that continuously regenerates in humans.
A pool of "resting cells" migrate to create new nerve cells in the part of the brain which deals with smell.
The system has been shown in mice and rats but it was believed it did not exist in the human brain.
Experts said the findings, published in Science, opened up the potential for research into repairing brains in conditions such as Alzheimer's disease and Multiple Sclerosis.
The researchers from the University of Auckland, New Zealand and the Sahlgrenska Academy in Sweden showed stem cells rest in certain areas of the brain, just beneath large fluid-filled chambers called ventricles.
But then they needed to work out how they got to the right part of the brain.
In many species, it was known that a tube filled with brain fluid enabled these cells to travel to the olfactory bulb - the region of the brain that registers smells - turning into nerve cells as they went.
But until now, this system had not been shown in humans.
Using several techniques, including a powerful electron microscope, the team identified the tube, and showed it contained stem cells as well as cells which were gradually turning into nerve cells as they travelled along.
The researchers said the addition of new nerve cells in the olfactory bulb in humans helped the system respond to different stimuli throughout a person's life.
Experts said the findings could be important for future research into brain cell repair in patients with neurodegenerative diseases such as Alzheimer's disease and Multiple Sclerosis and, importantly, that studies in mice would be applicable to humans.
Dr Mark Baxter, Wellcome Trust senior research fellow at Oxford University, said: "This study is exciting because it reveals a group of brain cells in the adult human brain that are continuously regenerating.
"This opens another direction by which we may discover ways to repair human brains that are damaged from injury or diseases, and underscores the importance of animal research in guiding biomedical research in humans."
Professor Sebastian Brandner, head of the division of neuropathology at the Institute of Neurology, University College London, said it has been known for decades that such cells were present in mice and rats.
"Understanding stem cell biology is essential to study brain repair in neurodegenerative diseases such as Alzheimer's and it is even possible that stem cells are the source of some brain tumours."
Source: BBC News Copywrite BBC MMVII