Therapeutical efficacy of a novel non-peptide bradykinin B2 receptor antagonist on brain edema formation and ischemic tissue damage in focal cerebral ischemia

2003 ◽  
pp. 205-207 ◽  
Author(s):  
Stefan Zausinger ◽  
D. B. Lumenta ◽  
D. Pruneau ◽  
R. Schmid-Elsaesser ◽  
N. Plesnila ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Receptor Antagonist ◽  
Brain Edema ◽  
Tissue Damage ◽  
Focal Cerebral Ischemia ◽  
Edema Formation ◽  
Bradykinin B2 Receptor ◽  
Ischemic Tissue ◽  
Brain Edema Formation

Role of Arginine Vasopressin V1 and V2 Receptors for Brain Damage After Transient Focal Cerebral Ischemia

2005 ◽  
Vol 25 (8) ◽  
pp. 1012-1019 ◽  
Author(s):  
Abedin Vakili ◽  
Hiroharu Kataoka ◽  
Nikolaus Plesnila
Keyword(s):  
Ischemic Stroke ◽  
Cerebral Ischemia ◽  
Brain Edema ◽  
Brain Damage ◽  
Arginine Vasopressin ◽  
Focal Cerebral Ischemia ◽  
Edema Formation ◽  
Transient Focal Cerebral Ischemia ◽  
Brain Edema Formation

Brain edema formation is one of the most important mechanisms responsible for brain damage after ischemic stroke. Despite considerable efforts, no specific therapy is available yet. Arginine vasopressin (AVP) regulates cerebral water homeostasis and has been involved in brain edema formation. In the current study, we investigated the role of AVP V1 and V2 receptors on brain damage, brain edema formation, and functional outcome after transient focal cerebral ischemia, a condition comparable with that of stroke patients undergoing thrombolysis. C57/BL6 mice were subjected to 60-min middle cerebral artery occlusion (MCAO) followed by 23 h of reperfusion. Five minutes after MCAO, 100 or 500 ng of [deamino-Pen(1), O-Me-Tyr(2), Arg(8)]-vasopressin (AVP V1 receptor antagonist) or [adamantaneacetyl(1), O-Et-d-Tyr(2), Val(4), Abu(6), Arg(8,9)]-vasopressin (AVP V2 receptor antagonist) were injected into the left ventricle. Inhibition of AVP V1 receptors reduced infarct volume in a dose-dependent manner by 54% and 70% (to 29±13 and 19±10 mm3 versus 63±17 mm3 in controls; P<0.001), brain edema formation by 67% (to 80.4%±1.0% versus 82.7%±1.2% in controls; P<0.001), blood-brain barrier disruption by 75% ( P<0.001), and functional deficits 24 h after ischemia, while V2 receptor inhibition had no effect. The current findings indicate that AVP V1 but not V2 receptors are involved in the pathophysiology of secondary brain damage after focal cerebral ischemia. Although further studies are needed to clarify the mechanisms of neuroprotection, AVP V1 receptors seem to be promising targets for the treatment of ischemic stroke.

Xanthine oxidase is not a major source of free radicals in focal cerebral ischemia

1991 ◽  
Vol 260 (2) ◽  
pp. H563-H568 ◽  
Author(s):  
A. L. Betz ◽  
J. Randall ◽  
D. Martz
Keyword(s):  
Uric Acid ◽  
Free Radicals ◽  
Cerebral Ischemia ◽  
Xanthine Oxidase ◽  
Brain Edema ◽  
Focal Cerebral Ischemia ◽  
Total Activity ◽  
Brain Regions ◽  
Free Radical Scavengers ◽  
Edema Formation

Xanthine oxidase (XO) has been proposed as an important source of free radicals during ischemia. This enzyme normally exists as a dehydrogenase (XD), but it is converted to XO in some ischemic tissues. Recently, treatment of animals with the XD and XO inhibitor allopurinol or with free radical scavengers before cerebral ischemia has been shown to reduce brain injury. Therefore, we studied conversion of XD to XO in three ischemic and nonischemic brain regions during focal cerebral ischemia resulting from permanent occlusion of the middle cerebral artery (MCAO) in anesthetized rats. In nonischemic brain, 16-22% of the enzyme was in the XO form. After 24 h of ischemia this value was not significantly different (10-15%). Neither the total activity of XO nor that of XD changed, indicating that there was no irreversible conversion of XD to XO. To further explore the possible role of XO, we examined the effect of various doses of allopurinol (5, 20, or 100 mg/kg given 1 h before MCAO or 100 mg/kg given 48, 24, and 1 h before MCAO) on uric acid accumulation, brain edema formation, and cerebral blood flow (CBF) 24 h after MCAO. All but the lowest dose of allopurinol greatly reduced the appearance of uric acid in the ischemic brain; however, only the highest dose of allopurinol had any beneficial effect on brain edema. This reduction in brain edema occurred without a significant improvement in CBF. Thus XO is probably not an important source of free radicals in this model of focal cerebral ischemia.

Blood—Brain Barrier Permeability and Brain Concentration of Sodium, Potassium, and Chloride during Focal Ischemia

1994 ◽  
Vol 14 (1) ◽  
pp. 29-37 ◽  
Author(s):  
A. Lorris Betz ◽  
Richard F. Keep ◽  
Mary E. Beer ◽  
Xiao-Dan Ren
Keyword(s):  
Cerebral Ischemia ◽  
Brain Edema ◽  
Relative Permeability ◽  
Sodium Transport ◽  
Focal Ischemia ◽  
Edema Formation ◽  
Ischemic Brain ◽  
Early Stages ◽  
Brain Edema Formation ◽  
Rate Of Accumulation

Brain edema formation during the early stages of focal cerebral ischemia is associated with an increase in both sodium content and blood–brain barrier (BBB) sodium transport. The goals of this study were to determine whether chloride is the principal anion that accumulates in ischemic brain, how the rate of BBB transport of chloride compares with its rate of accumulation, and whether the stimulation seen in BBB sodium transport is also seen with other cations. Focal ischemia was produced by occlusion of the middle cerebral artery (MCAO) in anesthetized rats. Over the first 6 h after MCAO, the amount of brain water in the center of the ischemic cortex increased progressively at a rate of 0.15 ± 0.02 (SE) g/g dry wt/h. This was accompanied by a net increase in brain sodium (48 ± 12 μmol/g dry wt/h) and a loss of potassium (34 ± 7 μmol/g dry wt/h). The net rate of chloride accumulation (16 ± 1 μmol/g dry wt/h) approximated the net rate of increase of cations. Three hours after MCAO, the BBB permeability to three ions (22Na, 36Cl, and 86Rb) and two passive permeability tracers {[3H]α-aminoisobutyric acid (3H]AIB) and [14C]urea} was determined. Permeability to either passive tracer was not increased, indicating that the BBB was intact. The rate of 36Cl influx was 3 times greater and the rate of 22Na influx 1.8 times greater than their respective net rates of accumulation in ischemic brain. The BBB permeability to 22Na relative to that of [3H]AIB was significantly increased in the ischemic cortex, the relative permeability to 86Rb was significantly decreased, and the relative permeability to 36Cl was unchanged. These results indicate that the stimulation in BBB sodium transport is specific for sodium. Further, chloride accumulates with sodium in brain during the early stages of ischemia; however, its rate of accumulation is low compared with its rate of transport from blood to brain. Therefore, inhibition of BBB sodium transport is more likely to reduce edema formation than is inhibition of BBB chloride transport. This study demonstrates that chloride is the principal anion that accompanies the accumulation of sodium in ischemic brain, but its rate of accumulation in brain is much less than its rate of movement into brain, and therefore inhibition of chloride uptake would have little effect on brain edema formation. There is a specific acceleration of blood-to-brain sodium transport during ischemia that is not seen with another positively charged ion, 86Rb. This is consistent with stimulation of brain capillary Na,K-ATPase activity in response to the elevated extracellular potassium concentration. Inhibition of potassium influx across the BBB would probably be more successful in lessening edema formation than accelerating potassium efflux. However, inhibition of blood-to-brain sodium transport is likely to be a more effective approach to reducing brain edema formation during the early stages of cerebral ischemia.

scholarly journals Release of Bradykinin and Expression of Kinin B2 Receptors in the Brain: Role for Cell Death and Brain Edema Formation After Focal Cerebral Ischemia in Mice

2005 ◽  
Vol 25 (8) ◽  
pp. 978-989 ◽  
Author(s):  
Moritz Gröger ◽  
Diane Lebesgue ◽  
Didier Pruneau ◽  
Jane Relton ◽  
Seong-Woong Kim ◽  
...  
Keyword(s):  
Cell Death ◽  
Cerebral Ischemia ◽  
Brain Edema ◽  
Brain Damage ◽  
Receptor Expression ◽  
Experimental Stroke ◽  
Edema Formation ◽  
Receptor Mrna ◽  
The Brain ◽  
Brain Edema Formation

Pharmacological studies using bradykinin B2 receptor antagonists suggest that bradykinin, an early mediator of inflammation and the main metabolite of the kallikrein-kinin system, is involved in secondary brain damage after cerebral ischemia. However, the time-course of bradykinin production and kinin receptor expression as well as the conclusive role of bradykinin B2 receptors for brain damage after experimental stroke have not been elucidated so far. C57/Bl6 mice were subjected to 45 mins of middle cerebral artery occlusion (MCAO) and 2, 4, 8, 24, and 48 h later brains were removed for the analysis of tissue bradykinin concentration and kinin B2 receptor mRNA and protein expression. Brain edema, infarct volume, functional outcome, and long-term survival were assessed in WT and B2−/− mice 24 h or 7 days after MCAO. Tissue bradykinin was maximally increased 12 h after ischemia (three-fold), while kinin B2 receptor mRNA upregulation peaked 24 to 48 h after MCAO (10- to 12-fold versus naïve brain tissue). Immunohistochemistry revealed that kinin B2 receptors were constitutively and widely expressed in mouse brain, were upregulated 2 h after ischemia in cells showing signs of ischemic damage, and remained upregulated in the penumbra up to 24 h after ischemia. B2−/− mice had improved motor function ( P<0.05), smaller infarct volumes (–38%; P<0.01), developed less brain edema (–87%; P<0.05), and survived longer ( P<0.01) as compared with wild-type controls. The current results show that bradykinin is produced in the brain, kinin B2 receptors are upregulated on dying cells, and B2 receptors are involved in cell death and brain edema formation after experimental stroke.

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