TY - JOUR
T1 - Tirilazad pretreatment improves early cerebral metabolic and blood flow recovery from hyperglycemic ischemia
AU - Maruki, Yuichi
AU - Koehler, Raymond C.
AU - Kirsch, Jeffrey R.
AU - Blizzard, Kathleen K.
AU - Traystman, Richard J.
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1995
Y1 - 1995
N2 - Acidosis may augment cerebral ischemic injury by promoting lipid peroxidation. We tested the hypothesis that when acidosis is augmented by hyperglycemia, pretreatment with the 21-aminosteroid tirilazad mesylate (U74006F), a potent inhibitor of lipid peroxidation in vitro, improves early cerebral metabolic recovery. In a randomized, blinded study, anesthetized dogs received either tirilazad mesylate (1 mg/kg plus 0.2 mg/kg/h; n = 8) or vehicle (n = 8). Hyperglycemia (400-500 mg/dl) was produced prior to 30 min of global incomplete cerebral ischemia. Intracellular pH and high energy phosphates were measured by phosphorus magnetic resonance spectroscopy. During ischemia, microsphere-determined CBF decreased to 8 ± 4 ml min-1 100 g-1 and intracellular pH decreased to 5.6 ± 0.2 in both groups. During the first 20 min of reperfusion, ATP partially recovered in the vehicle group to 57 ± 21% of baseline, but then declined progressively in association with elevated intracranial pressure. By 30 min, ATP recovery was greater in the tirilazad group (77 ± 35 vs. 36 ± 19%), although postischemic hyperemia was similar. By 45 min, the tirilazad group had a higher intracellular pH (6.5 ± 0.5 vs. 5.9 ± 0.6) and a lower intracranial pressure (18 ± 6 vs. 52 ± 24 mm Hg). By 180 min, blood flow and ATP were undetectable in seven of eight vehicle-treated dogs, whereas ATP was >67% and pH was >6.7 in six of eight tirilazad-treated dogs. Thus, tirilazad acts during early reperfusion to prevent secondary metabolic decay associated with severe acidotic ischemia. If tirilazad acts by inhibiting lipid peroxidation, then these data are consistent with extreme acidosis limiting recovery by a mechanism involving lipid peroxidation.
AB - Acidosis may augment cerebral ischemic injury by promoting lipid peroxidation. We tested the hypothesis that when acidosis is augmented by hyperglycemia, pretreatment with the 21-aminosteroid tirilazad mesylate (U74006F), a potent inhibitor of lipid peroxidation in vitro, improves early cerebral metabolic recovery. In a randomized, blinded study, anesthetized dogs received either tirilazad mesylate (1 mg/kg plus 0.2 mg/kg/h; n = 8) or vehicle (n = 8). Hyperglycemia (400-500 mg/dl) was produced prior to 30 min of global incomplete cerebral ischemia. Intracellular pH and high energy phosphates were measured by phosphorus magnetic resonance spectroscopy. During ischemia, microsphere-determined CBF decreased to 8 ± 4 ml min-1 100 g-1 and intracellular pH decreased to 5.6 ± 0.2 in both groups. During the first 20 min of reperfusion, ATP partially recovered in the vehicle group to 57 ± 21% of baseline, but then declined progressively in association with elevated intracranial pressure. By 30 min, ATP recovery was greater in the tirilazad group (77 ± 35 vs. 36 ± 19%), although postischemic hyperemia was similar. By 45 min, the tirilazad group had a higher intracellular pH (6.5 ± 0.5 vs. 5.9 ± 0.6) and a lower intracranial pressure (18 ± 6 vs. 52 ± 24 mm Hg). By 180 min, blood flow and ATP were undetectable in seven of eight vehicle-treated dogs, whereas ATP was >67% and pH was >6.7 in six of eight tirilazad-treated dogs. Thus, tirilazad acts during early reperfusion to prevent secondary metabolic decay associated with severe acidotic ischemia. If tirilazad acts by inhibiting lipid peroxidation, then these data are consistent with extreme acidosis limiting recovery by a mechanism involving lipid peroxidation.
KW - Antioxidants
KW - Hyperglycemia
KW - Magnetic resonance spectroscopy
KW - Tirilazad mesylate
KW - pH
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U2 - 10.1038/jcbfm.1995.10
DO - 10.1038/jcbfm.1995.10
M3 - Article
C2 - 7798342
AN - SCOPUS:0028801639
SN - 0271-678X
VL - 15
SP - 88
EP - 96
JO - Journal of Cerebral Blood Flow and Metabolism
JF - Journal of Cerebral Blood Flow and Metabolism
IS - 1
ER -