(Press-News.org) In a study at the University of California, San Diego and VA San Diego Healthcare, researchers were able to regenerate "an astonishing degree" of axonal growth at the site of severe spinal cord injury in rats. Their research revealed that early stage neurons have the ability to survive and extend axons to form new, functional neuronal relays across an injury site in the adult central nervous system (CNS).
The study also proved that at least some types of adult CNS axons can overcome a normally inhibitory growth environment to grow over long distances. Importantly, stem cells across species exhibit these properties. The work will be published in the journal Cell on September 14.
The scientists embedded neural stem cells in a matrix of fibrin (a protein key to blood clotting that is already used in human neuron procedures), mixed with growth factors to form a gel. The gel was then applied to the injury site in rats with completely severed spinal cords.
"Using this method, after six weeks, the number of axons emerging from the injury site exceeded by 200-fold what had ever been seen before," said Mark Tuszynski, MD, PhD, professor in the UC San Diego Department of Neurosciences and director of the UCSD Center for Neural Repair, who headed the study. "The axons also grew 10 times the length of axons in any previous study and, importantly, the regeneration of these axons resulted in significant functional improvement."
In addition, adult cells above the injury site regenerated into the neural stem cells, establishing a new relay circuit that could be measured electrically. "By stimulating the spinal cord four segments above the injury and recording this electrical stimulation three segments below, we detected new relays across the transaction site," said Tuszynski.
To confirm that the mechanism underlying recovery was due to formation of new relays, when rats recovered, their spinal cords were re-transected above the implant. The rats lost motor function – confirming formation of new relays across the injury.
The grafting procedure resulted in significant functional improvement: On a 21-point walking scale, without treatment, the rats score was only 1.5; following the stem cell therapy, it rose to 7 – a score reflecting the animals' ability to move all joints of affected legs.
Results were then replicated using two human stem cell lines, one already in human trials for ALS. "We obtained the exact results using human cells as we had in the rat cells," said Tuszynski.
The study made use of green fluorescent proteins (GFP), a technique that had never before been used to track neural stem cell growth. "By tagging the cells with GFP, we were able to observe the stem cells grow, become neurons and grow axons, showing us the full ability of these cells to grow and make connections with the host neurons," said first author Paul Lu, PhD, assistant research scientist at UCSD's Center for Neural Repair. "This is very exciting, because the technology didn't exist before."
According to the researchers, the study makes clear that early-stage neurons can overcome inhibitors present in the adult nervous system that normally work to maintain the elaborate central nervous system and to keep cells in the adult CNS from growing aberrantly.
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Additional contributors to the study include Yaozhi Wang, Lori Graham, Karla McHale, Mingyong Gao, Di Wu, John Brock, Armin Blesch, Ephron S. Rosenzweig, Binhai Zheng and James M. Conner, UCSD Department of Neurosciences; Leif A. Havton, UCLA Department of Neurology; and Martin Marsala, UCSD Department of Anesthesiology.
The work was supported by the Veterans Administration, National Institutes of Health (NS09881), Canadian Spinal Research Organization, The Craig H. Neilsen Foundation, and the Bernard and Anne Spitzer Charitable Trust.
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BOSTON – Invariant natural killer T-cells (iNKT) are a unique subset of immune cells that are known to influence inflammatory responses. Now, a scientific team led by researchers at Beth Israel Deaconess Medical Center (BIDMC) has found that iNKT cells play a protective role in guarding against obesity and the metabolic syndrome, a major consequence of obesity.
Their discovery, published on-line today in the journal Immunity, also finds that although iNKT cells are lost when humans become obese, they can be restored through weight loss, and further suggests that therapies ...
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The video shows beating heart muscle cells, or cardiomyoctes, at day 10 of differentiation.
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SAN FRANCISCO, CA—September 13, 2012— Scientists at the Gladstone Institutes have revealed the precise order and timing of hundreds of genetic "switches" required to construct a fully functional heart from embryonic heart cells—providing new clues into the genetic basis for some forms of congenital heart disease.
In a study being published ...
BOSTON, MA—Melanoma is the most dangerous type of skin cancer and is the leading cause of death from skin disease. Rates are steadily increasing, and although risk increases with age, melanoma is now frequently seen in young people.
But what if we could pinpoint when seemingly innocuous skin pigment cells mutate into melanoma? Researchers at Brigham and Women's Hospital (BWH) have achieved this. Teams led by Yujiang Geno Shi, PhD, from BWH's Department of Medicine, and George F. Murphy, MD, from BWH's Department of Pathology have discovered a new biomarker for the lethal ...
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Lung cancer patients with a history of smoking have 10 times more genetic mutations in their tumors than those with the disease who have never smoked, according to a new...
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Lung cancer patients with a history of smoking have 10 times more genetic mutations in their tumors than those with the disease who have never smoked, according to a new study from Washington University School of Medicine in St. Louis.
"None of us were surprised that ...
TEMPE, Ariz. – If you think this summer was hot, it's nothing compared to the summer of 1913, when the hottest temperature ever recorded was a searing 134 F in Death Valley, Calif. But while that reading was made 99 years ago, it is only being recognized today by the World Meteorological Organization (WMO) as the most extreme temperature ever recorded.
That's because an international team of meteorologists recently finished an in-depth investigation of what had been the world-record temperature extreme of 58 C (136.4 F), recorded on Sept. 13, 1922 in El Azizia, Libya. ...
CAMBRIDGE, Mass. (September 13, 2012) – Several years ago, biologists discovered that regular body cells can be reprogrammed into pluripotent stem cells — cells with the ability to become any other type of cell. Such cells hold great promise for treating many human diseases.
These induced pluripotent stem cells (iPSCs) are usually created by genetically modifying cells to overexpress four genes that make them revert to an immature, embryonic state. However, the procedure works in only a small percentage of cells.
Now, new genetic markers identified by researchers at ...
University of Rochester Medical Center scientists discovered new genetic evidence linking cholesterol and cancer, raising the possibility that cholesterol medications could be useful in the future for cancer prevention or to augment existing cancer treatment.
The data, published in the online journal Cell Reports, support several recent population-based studies that suggest individuals who take cholesterol-lowering drugs may have a reduced risk of cancer, and, conversely that individuals with the highest levels of cholesterol seem to have an elevated risk of cancer.
The ...
New research could clarify how inflammatory bowel diseases (IBD), conditions that include ulcerative colitis and Crohn's disease, are triggered and develop.
Scientists at Emory University School of Medicine have shown how the immune system can compensate for a "leaky gut" and prevent disease in mice that are susceptible to intestinal inflammation. These findings could explain why some individuals who are susceptible to developing IBD do or do not get the disease.
The results will be published online Sept. 13 in the journal Immunity.
"Our results suggest that when ...
Patients admitted to hospital with obstructed heart arteries were three times more likely to experience complications when they were in hospital if they felt they were not in control of their condition, according to research published in the October issue of the Journal of Advanced Nursing.
However, persistent anxiety on its own appeared to have little effect on whether patients experienced complications or not.
Researchers looked at 171 patients admitted to hospitals in the USA, Australia and New Zealand with acute coronary syndrome (ACS), following them for two years. ...
It isn't only birds that move south as autumn approaches. Some insects also live their lives on the same principle. A new study of migratory insects has just been published that shows that a considerably higher number of insects survive and migrate back south in the autumn than was previously believed.
"These results are really exciting, because we have managed to show that it really is profitable for insects to migrate north at the start of the summer", says Lars Pettersson, a Reader at the Department of Biology, Lund University, Sweden.
The findings help to fundamentally ...
