Glibenclamide, a Sur1-Trpm4 antagonist, does not improve outcome after collagenase-induced intracerebral hemorrhage

Abstract

The sulfonylurea 1 transient receptor potential melastatin 4 (Sur1-Trpm4) receptor is selectively expressed after intracerebral hemorrhage (ICH). This upregulation contributes to increases in intracellular sodium. Water follows sodium through aquaporin channels, leading to cytotoxic edema. Even after edema is thought to have resolved, ionic dyshomeostasis persists, as does blood-brain barrier (BBB) damage. Glibenclamide, a hypoglycemic agent that inhibits Sur1-Trpm4, has been shown to reduce BBB damage and edema following infusion of autologous blood into the brain (ICH) as well as after other brain injuries. In order to further assess efficacy, we used the collagenase ICH model in rats to test whether glibenclamide reduces edema, attenuates ion dyshomeostasis, improves BBB damage, and reduces lesion volume. We tested a widely-used glibenclamide dose shown effective in other studies (10 μg/kg loading dose followed by 200 ng/hr for up to 7 days). Early initiation of glibenclamide did not significantly impact edema (72 hours), BBB permeability (72 hours), or lesion volume after ICH (28 days). Recovery from neurological impairments was also not improved by glibenclamide. These results suggest that glibenclamide will not improve outcome in ICH. However, the treatment appeared to be safe as there was no effect on bleeding or other physiological variables.