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Spinal cord regeneration might actually be helped by glial scar tissue (What the..??)

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  • Spinal cord regeneration might actually be helped by glial scar tissue (What the..??)

    Dunno what to believe anymore! interesting read, check it out...

    Spinal cord regeneration might actually be helped by glial scar tissue

    Posted By News On March 30, 2016 - 5:30pm

    Neuroscientists have long believed that scar tissue formed by glial cells -- the cells that surround neurons in the central nervous system -- impedes damaged nerve cells from regrowing after a brain or spinal cord injury. So it's no wonder that researchers have assumed that if they could find a way to remove or counteract that scar tissue, injured neurons might spontaneously repair themselves.
    A new study by UCLA scientists now shows that this assumption might have been impeding research on repairing spinal cord injuries.
    In a study using mice, Dr. Michael Sofroniew and colleagues found that the glial scar tissue that forms after spinal cord damage might actually favor nerve cell regeneration. The research, published in Nature, could ultimately lead to new approaches to repair catastrophic spinal cord injury.

    "For 20 years, we have been applying technologies to prevent glial scarring in hopes of promoting nerve fiber regeneration, repair and recovery, but never observed a positive effect," said Sofroniew, a professor of neurobiology at the David Geffen School of Medicine at UCLA. "Now we find that disrupting glial scars actually harms nerve fiber regeneration that can be stimulated by specific growth factors."
    The spinal cord is a thick cable of nerve projections called axons that course from the brain to activate muscles, and from sensory organs back to the brain to provide feedback. Unlike peripheral nerves, which re-sprout axons when they are damaged, mature spinal neurons do not regrow axons in the part of the body where the injury has occurred -- such as when the spinal cord is cut or crushed -- which results in paralysis below the injury.

    Doctors have long figured that the major roadblock to recovery was the scar tissue formed by a type of glial cells called astrocytes. This is because, after injury, spinal nerve fibers do not regrow past such glial scars and appeared to be "stalled" within them. That thinking prompted the UCLA researchers to ask a simple question: If that were true, wouldn't preventing or removing scars encourage the nerves to regenerate?
    To answer that question, the researchers evaluated two types of mice -- one in which specific genes could be switched on to prevent the formation of scars and another engineered with genes that could dissolve scars after they formed. Using fluorescent imaging, the researchers then traced individual axons to see if they would approach or cross an injury site if the scarring was blocked or obliterated.
    In both cases, the axons showed no sign of regrowing through the lesion.

    "This clearly refuted the assumption that getting rid of scars would permit spontaneous regeneration of injured axons," Sofroniew said. "In fact, it hinted that scars might play some sort of positive role."
    The research also revealed glial scars' beneficial role in an experiment in which the scientists softly flog injured neurons into regenerating -- a strategy Sofroniew likens to a "carrot and a stick" approach. In either normal or genetically modified mice, neurotrophic growth factors (the carrot) are infused at the spinal injury site at the same time that additional lesions known to stimulate nerve regrowth (the stick) are applied.

    Remarkably, in the normal mice, the approach stimulated robust regrowth of the stalled spinal axons past glial scars and through the injury site. Even more remarkably, the mice that were engineered to eliminate scars showed a pronounced reduction in this stimulated nerve regeneration -- and in some cases, none at all.
    "This was a very surprising finding," said co-first author Mark Anderson, a former research associate in Sofroniew's lab who now is at Switzerland's ?cole Polytechnique F?d?ral de Lausanne. "Scar formation has long been considered the principal impediment to axon regeneration."

    Joshua Burda, the study's co-first author and a postdoctoral fellow in Sofroniew's lab, said the finding could prompt a new way of thinking in the field.
    "This paper may encourage some to shift their focus away from trying to decrease astrocyte activity, in particular in scar formation, and toward how to exploit it as a way to promote regeneration," he said.
    The team also performed a biochemical screen to identify molecules expressed in scar tissue and discovered relatively high levels of factors that support axon growth. This shows that scars are capable of producing chemical signals, albeit faint ones, that permit axons to grow over them. Thus, future strategies for repairing the central nervous system might involve concocting even more potent mixtures of growth factors, like Sofroniew's "carrot," that could be continuously infused or implanted near a patient's injury.

    Burda noted that the finding might have been downright predictable had researchers been thinking in terms of evolution.
    "Maybe it's not surprising that a highly evolved central nervous system wound response, such as scar formation, would play a crucial beneficial function in both wound healing and axon regeneration," he said.
    Added Sofroniew: "Techniques used in mouse models cannot be applied today in patients. But our work is an important scientific step toward developing strategies to get nerve fibers to regrow across severe spinal lesions. It opens the door to an area of research that has been inhibited by incorrect dogma."
    Source: University of California

    Last edited by Moe; 03-30-2016, 04:05 PM.
    "Talk without the support of action means nothing..."
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  • #2
    Some Neuroscientists have long believed ...


    • #3
      This lab news is interesting but the article is a bit confusing. For starters, I don't know how many researchers have ever believed that scar disintegration would miraculously cause spontaneous regeneration. (I'm sure they all know better than that). If it were the case, all SCI animal models would be have had 100% recovery with a Ch'ase injection. We'll see how future experiments play out in rats and other mammals since this study was done in mouse. The article seems to ignore and gloss over all the other problems that must be overcome to actually produce a meaningful therapy. Infusing a bunch of potent growth factors is one thing, but then creating additional new lesions next to the old ones doesn't seem like such a great idea as a therapy and especially if you're a chronic. They have a ways to go...


      • #4
        If you ask me Spinal Cord Injury Research is still in it's infancy. Most Doctors and researchers still have no clue about what really goes on in the Brain and the Spinal Cord, that is the real problem. Very complex structures that once broken may never see repair. Unfortunately the story is still the same in that all that those who are affected can only do the best we all can with whatever we were left with after our injuries. I've seen tons and tons of talk about all sorts of things since I've been injured but yet not much has changed since my accident May 9th of 1981. 35th celebration to still be alive coming up in a little over a month, if I'm still alive by then, I feel this injury puts us all at a lot more risk as we age.
        "Life is about how you
        respond to not only the
        challenges you're dealt but
        the challenges you seek...If
        you have no goals, no
        mountains to climb, your
        soul dies".~Liz Fordred


        • #5
          Very interesting indeed, I'm going to have to see if I can get the full article.
          Grammy, you are right they have a long ways to go, but of course this is how it starts. There is going to be proof-of-concept at all costs (creating lesions to guide the axons along), regardless of the feasibility. Now, hopefully, if we see more work on this line of research continue, they will have that feasibility in mind.