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Spider Venom Might Protect Us From Deadly Strokes (arstechnica.com)
New submitter evolutionary writes: Apparently the Australian funnel-web spider's venom has amazing properties, if you can use it within 4.5 hours. From a report via Ars Technica: "Venom from the Australian funnel-web spider (Hadronyche infensa) contains a chemical that shuts down an ion channel known to malfunction in brain cells after strokes, researchers report Monday in PNAS. In cell experiments, the harmless chemical protected brain cells from a toxic flood of ions unleashed after a stroke strikes. In rats, the venom component markedly protected the rats' brains from extensive damage -- even when it was given hours after a stroke occurred. Researchers have years, if not decades, of work to figure out if their particular venom is safe and effective in humans. And very few potential therapies make the cut. But, this early study gives us reason to be somewhat optimistic: it follows years of research and hypotheses that such venom components and their ion channel-targets could be key to new stroke treatments -- which are desperately needed. The vast majority of strokes involve a blockage that stops or slows the flow of blood into an area of the brain (other strokes can be caused by hemorrhages.) This leaves brain cells without fresh blood and oxygen. To cope, the cells can switch to metabolic pathways that don't rely on oxygen. But this creates acidic conditions, and the pH outside of brain cells starts dropping fast -- a scenario called acidosis. In the acidic, oxygen-starved brain regions, brain cells become damaged and start dying off, causing irreparable damage. The only drug approved by the Food and Drug Administration to treat these types of strokes tries to restore blood flow by breaking up clots. But this drug is only used in about three to four percent of stroke victims because it has to be used within 4.5 hours of the stroke. It also comes with the risk of causing hemorrhages."
To him, life is a great big hangup.
well, we consider YOU human (usually). So anything that is a higher lifeform than you should also count.
That answer your question?
"I do not agree with what you say, but I will defend to the death your right to say it"
why not another neuro-toxin? ask Peter.
When I had a stroke, the doctors could do nothing since they couldn't determine if it was due to a clot or bleeding. My neurologist said that is common. They couldn't do anything since there was a 50/50 chance whatever they did would make it worse. It's sad how little doctors can do. There's a few great stories, but in general they just typically have to let people suffer.
These results are from experiments on rats. In radio interviews, the researchers said that human (phase I) trials were at least 18 months away. I'm no expert on how long clinical trials take, but I'd expect phase I through phase III couldn't be under three years, so expect 5 + years until this is in your ambulance's medicine cabinet.
Try not to have a stroke before then.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Doctors are too paralyzed these days by liability. They have no backbone. I had my first stroke in 1972 and didn't have that problem. Fast action is what probably saved my life. Doctors today care more about money than patients so they so often do nothing.
I found this link. Ischemic is blocked and Hemorrhagic is bleeding. It sounds like there are signs of either and a CT or MRI can discriminate between the two. I assume there are borderline cases where they can't make a call, maybe like in minor stroke cases? Which I'm assuming yours was?
In any event, I'd be surprised if stroke was the only application for this. I'd assume this would be useful for other parts of the body deprived of blood flow. From my limited understanding, blood block and tissue death can happen in hernias in the guts, fingers and toes with certain blood pressure medications, and probably a bunch of other places.
I'm not a real doctor, so no idea if this is something that would only be useful in brains in a stroke, just seems like the potential uses for it are more than just one big thing like strokes, even if it's unlikely to ever be used to treat anything. (Most drug candidates turn out to not be good for anything really.)
How am I suppose to book a +20 hour flight to Australia while having a stroke? Not to mention tracking down this one particular spider w/o getting bitten by one of Australia's many other poisonous snakes or spiders along the way.
It must have been something you assimilated. . . .
Since both kinds of stroke cause damage by depriving brain regions of oxygen, this should be applicable to both.
To throw another wrench into the decision matrix, an ischemic stroke is caused by a clot that has been jammed into a narrow blood vessel. If the patient is not particularly healthy he may have fragile arterial walls, in which case the clot can damage the artery. Ironically, this may lead to the clot doing its intended task, becoming the thing preventing the damaged artery from hemorrhaging. In these rare and undiagnosable cases, responsibly using tPA (or spider venom) to dissolve the clot can actually lead to a hemorrhagic stroke.
John
Yes, the researchers give this as a major advantage of their discovery - you can give the (hypothetical future) drug without knowing which type of stroke the patient has.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
A CT scan can differentiate between an ischemic and a hemorrhagic stroke. You would not go for an MRI scan immediately since it takes too long and in the case of a stroke time equals brain.
Whether or not thrombolysis with rtPA is an option depends on a number of things, such as time from onset of symptoms to delivery into the ER, which has to be less than 4.5 hours, and whether or not any of the contraindications are met.
We've got quantum computing now.
I recall this news when it was first announced - more than 20 years ago!
Can i post here?
Consider the folowing, quoted from the summary:
...spider's venom... harmless chemical ...shuts down an ion channel... risk of causing hemorrhages.
I think it is irresponsible to talk about things like this in such a cavalier way. A compund that comes from the venom of a funnel-web spider, shuts down ion channels and may cause haemorrhages in the brain is hardly "harmless". Water is harmless, in moderation, just for comparison. Slashdot still tries to sell itself as "news for nerds", so please try to at least not dumbing down science and technology. Your readers are interested in these subjects and are at least trrying to understand, so try to respect that instead of treating us all like idiots.
Apparently the Australian funnel-web spider's venom has amazing properties, if you can use it within 4.5 hours."
That's completely missing the point. The venom's benefit is that it may reduce stroke damage without the same risk of hemorrhage. Making this the first line of the summary doesn't follow from the actual source, so I'm guessing it's just blatant sensationalist journalism. TFA doesn't mention how soon the venom has to be applied. The summary would be less misleading and overall better if the 4.5 hour qualifier wasn't in that first sentence.
This is why in the urgent situation, normal medical practice is if a stroke is suspected, the patient is transferred immediately to a CT scanner, as soon as a paramedic or doctor suspects the diagnosis. Ideally, the scan should be performed and the radiologist's opinion obtained within 30 minutes of the diagnosis being suspected. In the immediate situation, detection of significant quantities of blood can be made with near 100% sensitivity. With urgent MRI, results are even better with near 100% sensitivity for detection of ischaemic areas (regions with inadequate blood flow).
The problem is that if the stroke is old (i.e. a week or more), it can be very difficult or impossible to tell whether the stroke was due to bleeding or clot with a conventional CT. MRI, especially with modern ultra-sensitive blood detection techniques, can detect residual blood for years with near 100% sensitivity. At the same time, either CT or MRI angiography (blood vessel examination techniques) can look for evidence of arterial disease, which can be a clue as to the risk of a clot, even if the clot itself has dissolved by that point.
The fundamental difficulty, however, with delayed investigation, is that ischaemic strokes (due to clot) result in damage to the brain tissue and the blood vessels - so bleeding following an ischaemic stroke is very common. So, even if MRI does show blood a few weeks down the line, it is not always possible to tell, especially if a stroke is small, whether the bleeding was the cause or the effect. As it is small strokes which tend not to result in a blue-light ambulance trip to the ER, but instead an appointment with a GP or neurologist for some vague symptoms, this scenario is surprisingly common.
... including humans.
So while it was harmless in a rat, it's NOT in people.
Otherwise Aussies would be keeping funnelwebs as pets ;)
Basic indications for thrombolysis (clot busting) in presumed stroke.
- Persons of a certain age (typically over 18, pediatric strokes have not been studied well and typically are due to a bleed from a congenital malformation)
- There are blood pressure ranges over which it's felt that punching holes in the brain is too dangerous
- There are certain medications (other drugs that work on the blood clotting system) that, when mixed with the clot buster make it too dangerous
- You have to have a major stroke - the procedure doesn't work all that well and a bunch of complicated statistics and people yelling back and forth have made a guess with the benefit outweighs the risk.
- TIME IS IMPORTANT - this is one of the big deals. Stroke is being popularized as a 'brain attack' (which sounds too Zombieish to me). That's a bit of overkill but the longer the symptoms have gone on, the less likely that busting up the clot is going to work. THIS IS WHERE THE SPIDER VENOM may come in - by protecting the brain while you do something (or not). Would presumably work in ischemic (formed by a blood clot) or hemorrhagic (formed by a bleeding blood vessel) kind of stroke.
- You should get permission. Thrombolysis could make things better - or kill you. The improvement rate is only 25-40% (something less than thrombolysis for heart attacks). The big downside is that you convert an ischemic stroke into a thrombolytic stroke. Since blood in the brain can't leak out anywhere, you have to drill a hole in the brain which typically requires the presence of a neurosurgeon. Lots of places don't have neurosurgeons just wandering around. Yes, we've been trained in emergent craniotomy. I have this neat stainless steel drill that looks for all the world like an old carpenter drill but you don't want me to get it out of it's case. Very, very last ditch.
IF - and a big if - this pans out it could make stroke treatment much easier and more useful. It could also be used in any sort of insult to the neurologic system (trauma, etc.).. Cryosleep anyone?
But it's a big if...
Faster! Faster! Faster would be better!
That's because TPA didn't exist in '72. It is a powerful clot buster that can save the victim of an ischemic stroke but will probably kill someone with a hemorrhagic stroke. If they can't tell which type of stroke you have they will "first do no harm".
so this seems to be the same cascading apoptosis that occurs when the brain is starved of oxygen IN GENERAL... whether through stroke or something else like cardiac arrest. so this might have the same kind of effect as cryo immersion therapy - staving off the apoptosis that happens after resuscitating someone whose brain has been deprived of oxygen for a long period of time. but with this, not needing to induce hypothermia.
When I had a stroke, the doctors could do nothing since they couldn't determine if it was due to a clot or bleeding. My neurologist said that is common. They couldn't do anything since there was a 50/50 chance whatever they did would make it worse. It's sad how little doctors can do. There's a few great stories, but in general they just typically have to let people suffer.
I think the odds are about a 5/6 chance that it was a clot, based on the studies of strokes in general.