Evaluation of the microvasculature and cerebral ischemia after experimental subarachnoid hemorrhage in dogs

2002 ◽  
Vol 97 (4) ◽  
pp. 896-904 ◽  
Author(s):  
Eddie Perkins ◽  
Hitoshi Kimura ◽  
Andrew D. Parent ◽  
John H. Zhang

Object. Whether cerebral vasospasm occurs only in surface vessels or also in parenchymal arterioles is debatable. The present study was undertaken to evaluate comprehensively the microvasculature of the brainstem after experimental subarachnoid hemorrhage (SAH). Methods. Nine mongrel dogs of either sex, each weighing between 18 and 24 kg, underwent double blood injections spaced 48 hours apart; the injections were infused into the cisterna magna immediately after angiography of the basilar arteries (BAs). Three additional dogs assigned to a control group received no blood injections. The dogs were killed on Day 7. Axial sections obtained from the midpontine region of both control dogs and animals subjected to SAH were evaluated with respect to the morphological characteristics of vessels and neurons, and for ultrastructural changes. Severe vasospasm occurred in the BAs of all dogs subjected to SAH. Nevertheless, in these animals, the luminal areas and vessel perimeter in parenchymal arterioles, but not in parenchymal venules, were observed to have increased when compared with those of control dogs (p < 0.01, t-test). No corrugation of the internal elastic lamina was observed and smooth-muscle and endothelial cells remained normal at the ultrastructural level in the dogs with SAH. Conclusions. In this model, vasospasm of the BAs did not extend into the region of the pons to affect the intraparenchymal arterioles. Dilation of the parenchymal arterioles might serve as compensation for reduced blood flow. Thus, no neuronal ischemia or infarction resulted in the pontine region of the brain.

2002 ◽  
Vol 97 (1) ◽  
pp. 129-135 ◽  
Author(s):  
Hitoshi Kimura ◽  
Toshinari Meguro ◽  
Ahmed Badr ◽  
John H. Zhang

Object. The naphthylsulfonate derivative suramin is an inhibitor of growth factor receptors (receptor tyrosine kinases) and G protein—coupled P2Y receptors. Both types of these receptors are suspected of being involved in cerebral vasospasm after subarachnoid hemorrhage (SAH). In the current study, the authors examined the therapeutic effects of suramin and a selective P2X-receptor antagonist, pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS), in the reversal of vasospasm in an established canine double-hemorrhage model. Methods. Twenty-four dogs underwent double blood injection into the cisterna magna, with injections given on Days 0 and 2. The dogs were divided randomly into three groups (six animals in each group) to be treated from Days 2 through 6 with the vehicle dimethyl sulfoxide, suramin, or PPADS. An additional group of six dogs received double blood injection without any treatment and served as an SAH control group. The animals were killed on Day 7. Angiography was performed on Day 0 before blood injection and again on Day 7 before the animals were killed. After the death of the animals, the basilar arteries (BAs) were collected for morphological studies and determination of tyrosine kinase expression, and the bloody cerebrospinal fluid (CSF) produced by the hemorrhages was collected for measurement of oxyhemoglobin and adenosine triphosphate (ATP). In the SAH control group, the mean diameter of the BAs on Day 7 was 46.23 ± 6.32% of the value on Day 0 (which served as a reference of 100%). In the DMSO-treated group, the mean residual diameter of the BA was 47.77 ± 0.8% on Day 7 compared with the value on Day 0. Suramin, but not PPADS, increased the residual diameter to 74.02 ± 4.24% on Day 7. On Day 7 the level of ATP in the CSF was decreased and the level of oxyhemoglobin was increased, compared with values measured on Day 0. Suramin, but not PPADS, reduced tyrosine phosphorylation in the spastic BAs. Conclusions. By reducing tyrosine kinase activity, suramin may be useful in the treatment of cerebral vasospasm.


2004 ◽  
Vol 101 (1) ◽  
pp. 88-92 ◽  
Author(s):  
Gustavo Pradilla ◽  
Paul P. Wang ◽  
Federico G. Legnani ◽  
Lynn Ogata ◽  
Gregory N. Dietsch ◽  
...  

Object. Adhesion of leukocytes and their migration into the periadventitial space may be critical in the pathophysiology of vasospasm following subarachnoid hemorrhage (SAH). The cell adhesion molecules involved in this process are lymphocyte function—associated antigen—1 (CD11a/CD18) and macrophage antigen—1 (CD11b/CD18), which are present on neutrophils/macrophages, and intercellular adhesion molecule—1 (CD54), which is present in endothelial cells. A humanized monoclonal antibody (mAb), Hu23F2G, targets CD11/CD18 and prevents leukocyte adhesion to endothelial cells. In this study, systemic administration of Hu23F2G prevented vasospasm in the rabbit model of SAH. Methods. Twenty-six New Zealand White rabbits were injected with autologous blood into the cisterna magna to induce SAH, after which they were randomized to receive injections of either Hu23F2G (10 animals) or a placebo at 30 minutes and 24 and 48 hours after SAH (six animals). Control animals underwent sham operations (four animals) or SAH alone (six animals). The animals were killed 72 hours after SAH, their bodies perfused and fixed, and their basilar arteries processed for morphometric analysis. Peripheral white blood cells (WBCs) were counted at 72 hours. The percentages of lumen patency were compared using the Student t-test. The presence of neutrophils and macrophages was confirmed by immunohistochemical analysis in which a rat anti—rabbit anti-CD18 mAb and cresyl violet were used. Treatment with Hu23F2G resulted in the significant prevention of vasospasm. Animals treated with Hu23F2G had 90 ± 7% lumen patency compared with 65 ± 7% in the placebo group (p = 0.025). The percentage of lumen patency in the SAH-only group was 59 ± 10%. The mean WBC count was 16,300 ± 2710/µl in the treatment group, compared with 7000 ± 386/µl in the control group (p = 0.02). Administration of Hu23F2G produced increased numbers of WBCs in 70% of the animals treated. Conclusions. This study supports the concept that leukocyte—endothelial cell interactions play an important role in the pathophysiology of chronic vasospasm after SAH. Systemic therapy with an anti-CD11/CD18 mAb prevents vasospasm after SAH by inhibiting adhesion of neutrophils and macrophages and their migration into the periadventitial space.


1999 ◽  
Vol 90 (6) ◽  
pp. 1105-1114 ◽  
Author(s):  
Hiroki Ohkuma ◽  
Ian Parney ◽  
Joseph Megyesi ◽  
Aziz Ghahary ◽  
J. Max Findlay

Object. The purpose of this study is twofold: 1) to test antisense genetic techniques used in the prevention of cerebral vasospasm in a canine model of subarachnoid hemorrhage (SAH), targeting the endothelin-1 (ET-1) gene; and 2) to determine if fibrinolysis of subarachnoid clot with recombinant tissue plasminogen activator (rtPA) could enhance the effect of antisense treatment.Methods. A total of 39 dogs were studied in this experiment. Placebo (six animals), rtPA (six animals), antisense preproET-1 oligodeoxynucleotide (ASOD; five animals), or rtPA plus ASOD (combined treatment; six animals) was injected into the cisterna magna 30 minutes after a second SAH was induced on the 2nd day of the experiment. The animals were observed until Day 7, when they underwent follow-up angiography and then were killed; their basilar arteries were removed for analysis. Control animals included in this study (two animals in each group) received placebo, rtPA, ASOD, or rtPA plus ASOD without induction of SAH, or rtPA with mismatched (nonsense) preproET-1 oligodeoxynucleotide following SAH. Six additional dogs were analyzed earlier following SAH.Dogs that received placebo developed severe vasospasm (51 ± 8% of baseline caliber). Administration of ASOD alone resulted in a mild reduction in vasospasm (64 ± 13% of baseline caliber) and rtPA alone resulted in a moderate reduction in vasospasm (81 ± 5% of baseline caliber); however, the combined therapy of rtPA plus ASOD almost completely prevented vasospasm (95 ± 6% of baseline caliber), which was significantly different from all other groups (p < 0.05). Morphological analysis of the basilar arteries yielded results similar to angiography with respect to vasospasm severity. The ASOD treatment combined with rtPA resulted in reduced ET-1 expression, as demonstrated by immunohistochemical staining of the arteries, and reduced preproET-1 levels on Day 4, as measured by reverse transcription—polymerase chain reaction. Nonsense DNA sequences had no effect on the vessels.Conclusions. Antisense preproET-1 oligodeoxynucleotide treatment, when combined with clot lysis caused by rtPA, reduced vasospasm in the canine model of SAH, and this effect appeared to be related to reduced ET-1 synthesis. The results of this experiment support a causative role for ET-1 early in the course of vasospasm development in dogs. The apparent additive therapeutic effects of antisense and fibrinolytic treatments could be due to clot lysis, which allows better delivery of oligodeoxynucleotides to arteries within the subarachnoid space.


1980 ◽  
Vol 52 (3) ◽  
pp. 302-308 ◽  
Author(s):  
Charles Rothberg ◽  
Bryce Weir ◽  
Thomas Overton ◽  
Michael Grace

✓ The pathophysiological responses to experimental subarachnoid hemorrhage (SAH) were investigated in 20 spontaneously breathing cynomolgus monkeys. Four different volumes of fresh autogenous blood were used: 1.0, 1.33, 1.67, and 2.0 cc/kg. Five other animals had injection of 1.67 cc/kg of mock cerebrospinal fluid. Cerebral blood flow (CBF) was measured using the xenon-133 clearance technique. Respiratory rate and tidal volume were monitored by way of a Vertek pneumotach. The reduction of CBF after the SAH became more pronounced with increasing volumes of subarachnoid blood. The CBF remained reduced despite a return to normal of the cerebral perfusion pressure. Increasing SAH volumes were associated with greater abnormalities in the respiratory pattern, consisting of apnea and hyperventilation. These larger volumes were also associated with hypoxemia. Morbidity and mortality increased with increasing volumes of SAH, and are believed to be the result of a combination of decreased CBF, respiratory center disturbances, and pulmonary diffusion defects.


2003 ◽  
Vol 99 (2) ◽  
pp. 383-390 ◽  
Author(s):  
Gen Kusaka ◽  
Hitoshi Kimura ◽  
Ikuyo Kusaka ◽  
Eddie Perkins ◽  
Anil Nanda ◽  
...  

Object. Mitogen-activated protein kinase (MAPK) has been implicated in cerebral vasospasm after subarachnoid hemorrhage (SAH). This study was conducted to investigate whether Src tyrosine kinase, an upstream regulator of MAPK, is involved in cerebral vasospasm. Methods. An established canine double-hemorrhage model was used. Twenty-four dogs were divided into four groups: control, vehicle-treated, Src inhibitor PP2—treated, and Src inhibitor damnacanthal—treated groups. Vehicle (dimethyl sulfoxide), PP2, or damnacanthal was injected daily into the cisterna magna of 18 dogs at 3 to 6 days after induction of SAH. Angiography was performed on Day 0 (the day on which the first blood injection was administered to induce SAH) and on Day 7. Western blot analysis of Src and MAPK activation in basilar arteries (BAs) collected on Day 7 post-SAH was performed. Severe vasospasm was observed in the BAs of vehicle-treated dogs. Mild vasospasm was observed in all dogs treated with Src inhibitors. Phosphorylated Src and MAPK were increased after SAH and activation of these kinases in the BAs was abolished by PP2 and damnacanthal. Conclusions. The tyrosine kinase Src is an important upstream regulator of MAPK, and inhibition of Src might offer a new therapy in the management of cerebral vasospasm.


1983 ◽  
Vol 58 (3) ◽  
pp. 338-344 ◽  
Author(s):  
Eric W. Peterson ◽  
Erico R. Cardoso

✓ In three groups of cats, the authors studied the effect of subarachnoid hemorrhage (SAH) on the permeability of the blood-brain barrier (BBB) to the penetration of Evans blue-protein complex. One group received arterial hypertension alone, one group SAH alone, and one group SAH followed by arterial hypertension. Animals subjected to arterial hypertension alone showed areas of BBB breakdown. However, when cats were rendered hypertensive after SAH, there were no demonstrable BBB lesions. The SAH was produced by intracisternal injection of whole blood and hypertension by the intravenous injection of metaraminol. The preservation of the BBB after SAH is discussed. Vasospasm is considered as a possible hemodynamic variable responsible for the protection of the BBB from hypertensive damage. The need for a new model is proposed to further investigate the state of the BBB after SAH.


1992 ◽  
Vol 77 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Dennis G. Vollmer ◽  
Masakazu Takayasu ◽  
Ralph G. Dacey

✓ The reactivity of rabbit basilar artery and penetrating arteriolar microvessels was studied in vitro using an isometric-tension measurement technique and an isolated perfused arteriole preparation, respectively. Comparisons were made between reactivities of normal vessels and those obtained from animals subjected to experimental subarachnoid hemorrhage (SAH) 3 days prior to examination. Subarachnoid hemorrhage produced significant increases in basilar artery contraction in response to increasing concentrations of serotonin (5-hydroxytryptamine) (10−9 to 10−5 M) and prostaglandin F2α (10−9 to 10−5 M) when compared to normal arteries. In addition, SAH attenuated the relaxing effect of acetylcholine following serotonin-induced contraction and of adenosine triphosphate after KCl-induced basilar artery contractions. In contrast to the changes observed in large arteries, cerebral microvessels did not demonstrate significant differences in spontaneous tone or in reactivity to a number of vasoactive stimuli including application of calcium, serotonin, and acetylcholine. On the other hand, small but significant changes in arteriolar responsiveness to changes in extraluminal pH and to application of KCl were noted. Findings from this study suggest that intracerebral resistance vessels of the cerebral microcirculation are not greatly affected by the presence of subarachnoid clot, in contrast to the large arteries in the basal subarachnoid space. The small changes that do occur are qualitatively different from those observed for large arteries. These findings are consistent with the observation of significant therapeutic benefit with the use of calcium channel blockers without changes in angiographically visible vasospasm in large vessels. It is likely, therefore, that calcium antagonists may act to decrease total cerebrovascular resistance at the level of the relatively unaffected microcirculation after SAH without changing large vessel diameter.


1998 ◽  
Vol 88 (2) ◽  
pp. 298-303 ◽  
Author(s):  
Laura L. Horky ◽  
Ryszard M. Pluta ◽  
Robert J. Boock ◽  
Edward H. Oldfield

Object. Oxyhemoglobin (HbO2) causes vasospasm after subarachnoid hemorrhage (SAH). The most likely spasmogenic component of HbO2 is iron. Various iron chelators, such as deferoxamine, have prevented vasospasm in vivo with limited success. However, only chelators of iron in the ferric state have been studied in animal models of vasospasm after SAH. Because free radical formation requires the ferrous (Fe++) moiety and Fe++ is a potent binder of the vasodilator nitric oxide, the authors hypothesized that iron in the ferrous state causes vasospasm and that chelators of Fe++, such as 2,2′-dipyridyl, may prevent vasospasm. This study was undertaken to investigate the influence of 2,2′-dipyridyl on vasospasm after induction of SAH in a primate model. Methods. Twelve cynomolgus monkeys were randomly divided into two groups and then both groups underwent placement of an arterial autologous blood clot in the subarachnoid space around the right middle cerebral artery (MCA). The five animals in the control group received intravenously administered saline and the seven treated animals received intravenously administered chelator (2,2′-dipyridyl) for 14 days. Sequential arteriography for assessment of MCA diameter was performed before and on the 7th day after SAH. Conclusions. Prevention of cerebral vasospasm by means of treatment with continuous intravenous administration of 2,2′-dipyridyl is reported in a primate model of SAH. This result provides insight into the possible mechanism of delayed vasospasm after aneurysmal SAH and provides a potential preventive therapy for it.


1983 ◽  
Vol 58 (6) ◽  
pp. 843-850 ◽  
Author(s):  
Tetsumori Yamashima ◽  
Shinjiro Yamamoto

✓ Pathological changes of the cerebral arteries were studied in 30 dogs after subarachnoid injections of saline, fresh autologous blood, epinephrine, blood plus epinephrine, norepinephrine, or blood plus norepinephrine. Macroscopically, the circle of Willis was maximally dilated after the injection of epinephrine and was constricted following administration of blood plus epinephrine. Microscopically, neither saline nor blood produced abnormalities, except for minor changes of the adventitia in the latter. Epinephrine produced frank necrosis of smooth-muscle cells, which was subsequently replaced by fibrosis in the media of larger subarachnoid arteries, and the leakage of necrotic material from the infarcted hypothalamus contributed to these lesions. Blood plus epinephrine produced marked changes in the internal elastic lamina and tortuosities of the nuclei of smooth-muscle cells, while norepinephrine and blood plus norepinephrine produced only minor changes. Previously reported findings of morphological changes due to vasospasm after subarachnoid hemorrhage were confirmed experimentally, but such changes were found only after application of epinephrine. It is suggested that epinephrine produced the most severe vasospasm among the five substances tested.


2002 ◽  
Vol 96 (3) ◽  
pp. 510-514 ◽  
Author(s):  
Richard S. Veyna ◽  
Donald Seyfried ◽  
Don G. Burke ◽  
Chris Zimmerman ◽  
Mark Mlynarek ◽  
...  

Object. Vasospasm remains a significant source of neurological morbidity and mortality following aneurysmal subarachnoid hemorrhage (SAH), despite advances in current medical, surgical, and endovascular therapies. Magnesium sulfate therapy has been demonstrated to be both safe and effective in preventing neurological complications in obstetrical patients with eclampsia. Evidence obtained using experimental models of brain injury, cerebral ischemia, and SAH indicate that Mg may also have a role as a neuroprotective agent. The authors hypothesize that MgSO4 therapy is safe, feasible, and has a beneficial effect on vasospasm and, ultimately, on neurological outcome following aneurysmal SAH. Methods. A prospective randomized single-blind clinical trial of high-dose MgSO4 therapy following aneurysmal SAH (Hunt and Hess Grades II–IV) was performed in 40 patients, who were enrolled within 72 hours following SAH and given intravenous MgSO4 or control solution for 10 days. Serum Mg++ levels were maintained in the 4 to 5.5 mg/dl range throughout the treatment period. Clinical management principles were the same between groups (including early use of surgery or endovascular treatment, followed by aggressive vasospasm prophylaxis and treatment). Daily transcranial Doppler (TCD) ultrasonographic recordings were obtained, and clinical outcomes were measured using the Glasgow Outcome Scale (GOS). The patients' GOS scores and the TCD recordings were analyzed using the independent t-test. Forty patients were enrolled in the study: 20 (15 female and five male patients) received treatment and 20 (11 female and nine male patients) comprised a control group. The mean ages of the patients in these groups were 46 and 51, respectively, and the mean clinical Hunt and Hess grades were 2.6 ± 0.68 in the MgSO4 treatment group and 2.3 ± 0.73 in the control group (mean ± standard deviation [SD], p = 0.87). Fisher grades were similar in both groups. Mean middle cerebral artery velocities were 93 ± 27 cm/second in MgSO4-treated patients and 102 ± 34 cm/second in the control group (mean ± SD, p = 0.41). Symptomatic vasospasm, confirmed by angiography, occurred in six of 20 patients receiving MgSO4 and in five of 16 patients receiving placebo. Mean GOS scores were 3.8 ± 1.6 and 3.6 ± 1.5 (mean ± SD, p = 0.74) in the treatment and control groups, respectively. Significant adverse effects from treatment with MgSO4 did not occur. Conclusions. Administration of high-dose MgSO4 following aneurysmal SAH is safe, and steady Mg++ levels in the range of 4 to 5.5 mg/dl are easily maintained. This treatment does not interfere with neurological assessment, administration of anesthesia during surgery, or other aspects of clinical care. We observed a trend in which a higher percentage of patients obtained GOS scores of 4 or 5 in the group treated with MgSO4, but the trend did not reach a statistically significant level. A larger study is needed to evaluate this trend further.


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