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Biotech

Light Could Make Paralyzed Limbs Move 63

Posted by samzenpus
from the walking-on-sunshine dept.
Zothecula writes "In a study that could eventually restore movement to humans' paralyzed limbs, researchers at California's Stanford University have used light to induce muscle contractions in mice. A gene derived from algae was inserted into the mice, encoding a light-sensitive protein which adhered to their nerve cell surfaces. Scientists then placed an 'optical cuff' lined with tiny, inwards-facing LEDs around the mice's sciatic nerves. By penetrating those nerves with brief, high-intensity bursts of blue light, they were able to produce muscle contractions similar to those that would occur naturally. The technology is called 'optogenetics.'"
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Light Could Make Paralyzed Limbs Move

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  • Got ED? (Score:2, Funny)

    How long until some uses this for erectile dysfunction? Lol
    • Got ED? Get LED! Solving one acronym with another similar one.
    • by cappp (1822388)
      Won't work. Erections are based on blood flowing into spongy erectile tissues allowing them to become engorged and causing stiffening and hopefully lengthening. This procedure allows muscular contraction, a completely different system.

      Have a read of TFA, the really fascinating part isn't addressed in the summary at all. This light-based system replaces an electric-stimulation system, the development and reasons for shifting from one to the other makes for a pleasant read.
      • actually, it totally could work. erections occur because certain smooth muscle in the penis relaxes, allowing blood to flow in the right places. ED drugs block the degradation of a chemical that promotes this relaxation. a light gated receptor of the proper type (Gi) could be designed to do the same thing.
        • by cappp (1822388)
          Don't forget that the relaxation is only half the equation - there is still a need for massive dilation in the veins delivering blood and a restriction in those removing it.

          How would this tech' be applied to relaxing muscles? I thought it was more complicated to stimulate relaxation than contraction, at least without the use of drugs.
          • Re:Got ED? (Score:4, Informative)

            by scapermoya (769847) on Wednesday September 29, 2010 @11:05PM (#33743214) Homepage
            1) veins don't deliver blood, arteries do

            2) the relaxation I was referring to was of the smooth muscle in the walls of the arteries leading to the penis

            3) there isn't much regulation of bloodflow that takes place on the venous side (ie venous drainage is relatively constant). thus if you increase flow inward it will necessarily lead to pooling (ie erection)

            the classic ED drugs all work by relaxing the arteries that flow toward the penis by inhibiting PDE5, a phosphodiesterase predominantly found in penis arteries. this increases cAMP levels, leaving to vasodilation and an erection. unfortunately these drugs aren't perfectly specific, and cause small amount of vasodilation throughout the body, along with a corresponding drop in blood pressure. this is why they tell you not to take the ED pills if you take other vasodilators like nitroglycerin.

            if you could engineer a Gs (i was wrong in my earlier post when I said Gi, you want more cAMP not less) receptor that was light sensitive, and get it to express only in the penis artery smooth muscle.... and shine light through your skin to activate these receptors, it would work the same way.

            obviously not an ideal way to treat a disorder. these light gated channels are probably only good for basic scientific research.
            • by cappp (1822388)
              Huh, pretty interesting idea though - and certainly better than flooding the body with drugs. Bit of creative material use in luminous condoms combined could be well rewarded. Thanks for that post; it’s exactly the kind that keeps me coming back to Slashdot.
            • by TamCaP (900777)
              There is a perfectly functioning Gi receptor that is sensitive only to orally bioavailable designer drug called CNO - the receptor's name is hM4Di (also known under a sexy name of DREADD). Now lets talk delivery :D
            • +1 Informative, but one small correction, The drug works by inhibiting the degradation of cGMP, not cAMP. More on that here [wikipedia.org].

              • woah, you're totally right. my professor screwed that one up. we were taught that PDE5 cleaves both cAMP and cGMP, but it looks like only PDE1, 2, and 3 cleave both.

                the downstream effects would be almost identical though. both cAMP and cGMP cause myosin light chain kinase to be phosphorylated by their respective kinases (PKA and PKG), leading to lower myosin activity and thus relaxation.

                nice catch!
                • Yes, but cAMP has so many other functions that a drug affecting it would have many more side-effects - which is exactly why PDE5 was chosen as a drug target (for the original anti-pulmonary hypertension drug).

            • by ooshna (1654125)
              I don't think this would work remember the penis has to stay hard in what is pretty must a dark wet cave. Unless you create a mini miners helmet there would be no light.
            • 1) veins don't deliver blood, arteries do

              Arteries don't deliver blood either, no more than a riverbed transports a river or the fish within it. And even if you were correct, the notion of blood delivery would be incidental and wrong headed. The blood delivers oxygen from, and returns carbon dioxide to, the lungs. The heart is what moves the blood.

              /pedant

              • that's semantics.

                in the context of what the poster was saying, i was pointing out that it is arteries that serve as conduits for blood that is flowing toward the penis (and all other tissues of the body), and veins are what serve as conduits for blood flowing away from the tissues.

                thanks for your deep insight though.

                /medical student
                • that's semantics.

                  Why is accuracy always dismissed as merely being semantics, as though using proper linguistics and meanings were unimportant and trivial? Without semantics, everyone would be a babbling idiot. Semantics is of the utmost importance in intelligent discourse.

                  I humbly recommend that if you succeed at your discipline, and become licenced, that you pay more respect to experienced registered nurses than you have shown for language and how it's understood. Both can, and more than likely will, save your ass.

                  /doc

                  • not always, just when the correction is trivial and doesn't contribute to the understanding at hand. isn't hyperbole ("always") a more dangerous use of language? so much for respect.

                    to be completely accurate, arteries do indeed 'deliver' blood, as they are responsible for the distribution of the blood to the body. feel free to pop open oed, which I'm sure a doctor of your caliber has at the ready, if you doubt me.

                    additionally, the elastic quality of the major arteries allows for pumping of blood outside
            • The veins still have smooth muscle - won't it be easier to contract it?
              • there is a moderate amount of smooth muscle found in the venous system. from what I have been taught (only in my first year of medical school), these muscles are not under the same kind of highly-specific nervous system control that the muscle in arteries is under. ie, your body has a hard time selectively contracting/relaxing specific veins. these muscles are predominantly under hormonal control, meaning that their contraction is regulated at a body-wide level.

                the vast majority of control over where blood
      • As someone who has worked with both channelrhodopsin and halorhodopsin in optogenetics, I assure you that you're quite mistaken. The decision to direct blood flow towards the male genitalia is ultimately processed by muscles that restrict blood flow to the penis when they are contracted. Adding halorhodopsin to these muscle cells, which causes hyperpolarisation and blocks action potentials from having an effect, would indeed permit a light-inducible erection.

        Only on Slashdot do you find such answers.
        • by cappp (1822388)
          I was merely saying that the article explicity addressed using light to contract muscles, that was all. Using the method as described in the article, without some refinement as you described, wouldn't do the job as far as I know. Clearly I should have been clearer with the point I was making and if there was an edit button I'd be clicking it pretty hard right now. Thanks for pointing out the mistake though, it's always cool hearing from someone with actual direct knowledge.
        • by TamCaP (900777)
          First, we all now that current version of halorhodopsin sucks. Talk to KD or GF - they are still trying to improve Halorhodopsin to cause any serious hyperpolarization at reasonable light levels. On the other hand, the current chr2s work just fine. Instead of placing halo in the muscle put chr2s in the neurons that are inhibitory to the ones causing muscle contraction. Actually, anyone knows how exactly the circuitry down there works?
          On the other hand, going at it with an optical fiber sticking out your b
    • That was my very first thought, though for ED it's more about relaxing those muscles, not tightening them.

      • Incidentally, we have light-activated ion channels that can do both. Channelrhodopsin causes a signal to be sent (depolarisation). Halorhodopsin, which was isolated from an archaean, causes hyperpolarisation and can prevent signalling. The great thing is that their activation wavelengths are different enough that you can use them in the same cell with different lights to control them.
    • How long until some uses this for erectile dysfunction? Lol

      Hey baby, check out my huge glowstick!

    • Hmm, Sea, sand, sun == sex now more than ever.
  • I bet people would be masters of raves and/or the disco with proper application of this tech.

  • Yet another thing I should have thought of myself but didn't. The idea seems generally simple and solves the problem of the interface between living tissue and synthetic components.

    I wonder, though, if this foreign tissue interface wouldn't simply get rejected and attacked by the body? Other concerns that occur to me are in the fact that light does get in through the body even if is is just a little. What problems could that cause?

    This seems slightly less than ideal, but does address the problem of a syn

    • " Other concerns that occur to me are in the fact that light does get in through the body even if is is just a little. What problems could that cause?"

      It's just blue light. A UV filter might be good, but it's not strong enough to burn or anything, and is going to be directed via fiber optics to the cells that are sensitized.

      I mean, the laser light is kind of a small matter when you're talking about injecting a virus to cause cells to express new genes and become sensitive to light.

  • This is cybernetics (Score:3, Interesting)

    by foniksonik (573572) on Wednesday September 29, 2010 @10:23PM (#33742994) Homepage Journal

    This is technology that could drive real cyberorganisms. Artificial muscle and nerves coupled together with this light sensitive protein and an optical system controlled by an electronic brain (or quantum super computer if you prefer).

    We've even demonstrated glucose power cells. All that's left is a circulatory system to feed the tissue.

    Cool indeed.

    • by EEPROMS (889169)
      yes an organic enhanced exoskeleton came to mind when I read this. I can imagine them being grown to fit specific users needs either for heavy industry or the military use so they can carry larger and more heavier items.
    • Unless it can connect directly to the central nervous system it isn't any better than current electro-stimulation. Possibly it is worse if you also need to genetically modify a person. Instead of genetically modifying cells with light receptors from other organisms (this is just rehashing previous gene splicing), they should focus on finding mechanisms to regrow nerves in humans so they can rebuild the original neural architecture that was damaged in the person. That and finding a way to trigger the ability
      • Missing the point. The thought is for machines to use this to gain muscles. There is a central nervous system, the CPU. It would direct light pulses to lab grown muscle tissue attached to artificial bone material with artificial vascular vessels to feed them nutrients.

        Completely artificial yet organic body controlled by a digital brain via optics.

    • Read "Fallen Dragon" by Peter F. Hamilton (link: http://en.wikipedia.org/wiki/Fallen_Dragon [wikipedia.org])

      They have "Skin Suits" of artificial muscle, which is very close to what you describe.

      These suits, however, are worn by humans, and are not 'cyberorganisms'.

  • But can it make dead and severed limbs move again? mmmmh, zombies.
    • by sharkey (16670)
      Beware of bathrooms.
    • by pwnies (1034518)
      Yes it can, but only temporarily. Severed limbs still have living cells in them. Applying an electric charge to them *will* make them move, although this process uses the existing neural pathways to deliver the charge (similar to how the body does it). These pathways run out of steam pretty quickly though, so it'd probably only work for a few minutes after the limb was removed.
  • Since they are adding foreign organic materal into the host, doesn't that mean the host would have to have immune suppressants to stop his body from destroying the cells.

    Sounds like its far from a perfect. You might be able to restore functionality to disabled limbs, but at the cost your your immune system.

  • ...that the Religious Right is going to kick up such a fuss about this. Anything that involves genetics sends them into a tizzy. Then it's likely that the Republicans will kowtow to the religious wingnuts, the Democrats will fold like a tent, and the research will be set back by years. A pity, really, given the potential of this research to alleviate some human suffering.
    • by a_hanso (1891616)
      Not if we go with the headline Divine Light makes cripples walk!
    • by ScentCone (795499)
      Anything that involves genetics sends them into a tizzy

      Actually, my observation is that it's the lefty wingnuts that have the biggest fits about genetic engineering. Which is ironic, of course, since the founders of the Progressive movement were also big fans of eugenics.
  • by mr_mischief (456295) on Thursday September 30, 2010 @12:26AM (#33743606) Journal

    If they can make muscles contract and relax according to the supply or lack thereof of a bright light, then a great next step is to get a bundle of nerve tissue to generate a bright light when they are excited. Then fiber optics could potentially be used as artificial nerve tissue to route around damage. The limits of bioluminescence might not allow for interaction with this, though.

    Even if there's an inorganic portion needed to generate a bright enough light, having that controlled directly by nerve tissue (and maybe fueled by ATP or body heat if possible) could be a huge advance over the conductive wires and external battery bags being tested now.

  • Reminds me of 'Biophotonics' which, IMHO, is inappropriately categorized as 'Pseudoscience' more often than not.

    http://en.wikipedia.org/wiki/Biophoton [wikipedia.org]

    http://en.wikipedia.org/wiki/Fritz-Albert_Popp [wikipedia.org]

    CC.
  • by Anonymous Coward

    On every family photograph, Rupert was an embarrasment. How he managed to flail just when the flash went off remained a mystery to the photographer.

  • With this technology, the user has to stay out of the sun, otherwise his limbs will twitch uncontrollably, so only Geeks living in basements need apply...
  • My microwave oven has been making hotdogs dance for years.

  • Now perhaps they can try experimenting on their intended target: humans.

  • I wonder if this could be used to enhance the nervous system,
    such as those stories of people with amazing levels of strength
    I think it might shed some light on this subject.

  • What's the advantage over using electrical impulses to contract muscles? AFAIK, we've made frog legs move since near the dawn of electricity.

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