Leeds: Ion channel modulator from scorpion venom preserves heart bypasses

A toxin found in the venom of the Central American bark scorpion Centruroides margaritatus could be developed as a treatment to prevent the occlusion, or blocking, of cardiac bypasses, according to researchers at Leeds University.

The toxin, margatoxin, is at least 100 times more potent at preventing neointimal hyperplasia, the most common cause of bypass graft failure, than any other known compound.

The toxin works by inhibiting the activity of a specific potassium ion channel. “We knew from experimental research in immunology that the ion channel Kv1.3 is involved in activating immune system responses and that it’s linked with chronic inflammation problems in the immune system, such as those you see with multiple sclerosis,” said researcher David Beech. “Since our own studies had identified Kv1.3's presence in injured blood vessels, which are also often complicated by chronic inflammation, we wanted to see if the same immune system blockers would inhibit neointimal hyperplasia.”

There were a number of good blockers of this ion channel available to screen but margatoxin was the most potent of all these compounds by a significant margin.

Beech says margatoxin would probably be unsuitable as a drug that could be administered orally or injected, but it could potentially be taken forward as a spray to treat the vein itself once it has been removed and is waiting to be grafted onto the heart.

References

Potent suppression of vascular smooth muscle cell migration and human neointimal hyperplasia by KV1.3 channel blockers
Cheong, A. et al.
Cardiovascular Research 2010
http://dx.doi.org/10.1093/cvr/cvq305. A copy of the paper is also available at http://bit.ly/agLIFv