Hemorrhagic transformation after
ischemic stroke is an independent predictor for poor outcome and is characterized by blood vessel
rupture leading to
brain edema. To date, no
therapies for preventing hemorrhagic transformation exist.
Disintegrins from the
venom of Crotalus atrox have targets within the coagulation cascade, including receptors on platelets. We hypothesized that
disintegrins from C. atrox
venom can attenuate hemorrhagic transformation by preventing activation of
matrix metalloproteinase after
middle cerebral artery occlusion (MCAO) in hyperglycemic rats. We subjected 48 male Sprague-Dawley rats weighing 240-260 g to MCAO and
hyperglycemia to induce hemorrhagic transformation of the
infarction. At reperfusion, we administered either saline (vehicle), whole C. atrox
venom (two doses were used), or fractionated C. atrox
venom (HPLC Fraction 2). Rats were euthanized 24 hr post-ictus for measurement of
infarction and
hemoglobin volume. Reversed-phase HPLC was performed to fractionate the whole
venom and peaks were combined to form Fraction 2, which contained the
disintegrin Crotatroxin. Fraction 2 protected against hemorrhagic transformation after MCAO, and attenuated activation of
matrix metalloproteinase-9. Administering
matrix metalloproteinase antagonists prevented the protection by Fraction 2. The results of this study indicate that
disintegrins found in C. atrox
venom may have therapeutic potential for reducing hemorrhagic transformation after
ischemic stroke. Moreover, the RP-HPLC fractions retained sufficient
protein activity to suggest that gentler and less efficient orthogonal chromatographic methods may be unnecessary to isolate
proteins and explore their function.