To be honest, spiders — fascinating as they may be to some — are not my favorite critters. That's likely because having suffered some pretty painful spider bites, I connect them with unfortunate consequences. Yet, as we've discussed in the past, components of spider venom can be a good thing, helping actually to decrease pain in some circumstances. And recent work published in the Proceedings of the National Academy of Sciences indicates that other ingredients in at least one spider's venom could help mitigate the effects of a stroke on the brain.
The Australian funnel-web spider is one of the world's most deadly. Its bite can be fatal to humans, especially to children, the elderly and the infirm. Yet even this particular cloud has a silver lining.
When an artery delivering blood to the brain is blocked, there is loss of oxygen delivery and tissue damage ensues — an ischemic stroke. The extent of the damage depends on how much tissue was 'fed' by that particular artery. One result of this blockade is that the pH of the affected tissue drops, i.e., it becomes more acidic. This pH decline is then sensed by the acid-dependent ion channel 1a (ASIC1a). Previous research has demonstrated that activation of ASIC1a is a precursor to tissue damage as a result of ischemia, because either genetic manipulation to remove that channel or its partial blockade by drugs reduces the area of damage in lab mice after ischemic stroke induction.
The authors of the PNAS study, led by Dr. Irène R. Chassagnon from the University of Queensland, Australia, isolated a peptide from the venom of the funnel web spider — Hi1a — that "incompletely inhibits ASIC1a activation in a pH-independent and slowly reversible manner." What this means is that the effect of Hi1a lasts for an extended period compared to other inhibitors. Indeed, the investigators found that the protection from tissue damage conferred by inhibiting the ion channel lasted for nearly 8 hours in a rat model of ischemic stroke.
Thus, if these results can also be applied to human stroke victims, there could soon be a means of forestalling the amount of neural tissue damaged by a blockage to an artery feeding the brain. In turn, this means that at least some of the debilitating effects of ischemic stroke, such as difficulty in walking or speaking (depending on the area of the brain affected), could be prevented or at least ameliorated.
Hopefully further research soon will be able to extend such results to humans. Obviously, one doesn't have to like spiders to appreciate the contributions that some can make to actually improving human health.
