Photoswitch Therapy Restores Vision To Blind Lab Animals 17
Zothecula writes: A new genetic therapy that helped blind mice and dogs respond to light stimulus could restore sight to people who suffer from diseases such as retinitis pigmentosa (a gradual loss of vision from periphery inwards). The therapy uses chemicals known as photoswitches, which change shape when hit with light, to open the channels that activate retinal cells. Treated mice can distinguish between steady and flashing light (abstract), while dogs with late-stage retinal degeneration also regain some sensitivity to light.
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Re:Evil psychopaths (Score:5, Insightful)
Imagine if it were YOU being tortured... having your eyes destroyed for an 'experiment'... Oh, wait! I'm on Slashdot! Most people here are sociopaths, who can't feel the suffering of others... and have to spend their entire lives PRETENDING to give a toss about other human beings, let alone animals...
The dogs were already suffering from the same disease. No dogs eyes were "destroyed for an experiment." FTFA:
The dogs were chosen because they have inherited a genetic disease caused by the same gene defect as some people with retinitis pigmentosa. Several of them at PennVet were treated and are currently undergoing tests to determine what degree of light sensitivity they now have.
Are you ready for a weekly needle in the eyeball? (Score:2)
He notes that the therapy works only for about a week after a single “charging” with the photoswitch, because the protein and attached chemical get recycled by the cell. While the modified receptors are replaced continually, since the new gene remains forever in the DNA, the chemical photoswitch – maleimide-azobenzene-glutamate, or MAG – must be resupplied by injection into the eyeball. Right now this means injection every week or so, with the future development of a slow release formulation less often.
You can't do weekly injections into the human eyeball over for the rest of the patients' life.
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You can't do weekly injections into the human eyeball over for the rest of the patients' life.
Eye catheters would be a bit annoying, I imagine.
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Perhaps, but every needle injection increases the risk of infection of the eyeball. My grandfather recently had a fake eye inserted after a single eye injection resulted in a streptococcus infection in that eye.
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Exactly. Sorry about your grandfather. Every procedure carries a risk. The infection rate is about 1 in 1,000. So, given 2 eyes, that brings it down to 1 in 500. 52 weeks a year, brings it down to more than 1 in 10 per year - or a 50% chance you'll get a serious infection within 5 years. And then there are all the other complications, such as cataract formation, other side effects of the drug, tear in the retina, detached retina, etc.
When I asked about using injections of AVGF (anti-venous growth facto
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Do injections in the eyball cause sigificant damage that would prevent them being used on a regular basis or are you just talking about the "what the patient will put up with" factor?
I would think that if the alternative was blindness patients would put up with weekly injections into the eyeball. From some googling it seems there are already eyeball injected drugs that are given every two months.
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There's a huge difference between "every 2-3 months for 2 years" and "every week forever".
I asked about the possibility of AVGF injections into my eyes to slow down the growth of blood vessels on the surface of the retina, and was told "that would be insane. You'd need them every month in both eyes, and even that wouldn't be enough. The risk is too high." I'll trust my retinal specialists over any "googling." And honestly, hospital visits for injections in both eyes every week for some sort of "pseudo-visi
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The thing is, this is just another step in progression. I don't think they are recommending this same procedure for humans. Sensitivity to light is a huge leap forward into restoring partial, then full sight. Conventional wisdom today says that if your retinas stop responding to light, you are done. This procedure allows them to begin responding to light via another mechanism. Sure, it's not sight at this point, but that is what further research will produce.
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More likely IMHO is that some sort of implantable slow-release reservoir system will be developed. Now you're down to surgery maybe once a year if all goes well.