The effect of mexiletine on the level of lipid peroxidation and apoptosis of endothelium following experimental subarachnoid hemorrhage

OBJECTIVE: The role of apoptosis in etiopathogenesis of vasospasm is not clearly understood yet. It is widely accepted that protection of the endothelial cells from the process of apoptosis could have beneficial effects on cerebral vasospasm after subarachnoid hemorrhage (SAH). Mexiletine blocks sodium and calcium channels and activates ATP-sensitive K(+) channels. Moreover, mexiletine is known to have potent antioxidant effects through inhibiting free-radical production. METHODS: Twenty-one rabbits were allocated into three groups randomly. Group I was sham operated group (n=7). SAH occurred but no medication was given to the Group II rabbits (SAH only group) (n=7). Mexiletine (50 mg/kg, b.i.d., i.p.) was administered just before SAH and continued until 48 hours following SAH to the Group III rabbits (Mexiletine treated group) (n=7). The ApopTag peroxidase in situ apoptosis detection kit (Serologicals Corporation, former Intergen) was used to demonstrate apoptosis in a cross section of basillary arteries. Thiobarbituric acid reactive material was used to determine the lipid peroxidation levels. RESULTS: There was a statistically significant difference between lipid peroxidation product levels of the control and SAH only groups (p<0.05). The level of lipid peroxidation production in Mexiletine treated group was significantly lower compared with SAH only group (p<0.05) but not significantly higher than the control group (p>0.05). DISCUSSION: In the present study we investigated the antioxidant action of mexiletine on apoptosis of endothelium following a rabbit SAH model. This experimental study directly suggested that lipid peroxidation is an important step in development of apoptosis in endothelial cells and prevention of structural integrity of endothelial cell should play a beneficial role in attenuation of cerebral vasospasm. Mexiletine treatment prevented the increase in lipid peroxidation and cerebral vasospasm. Examination of endothelial cells by staining specific for apoptosis demonstrated significant protection of cell integrity in the treated group.     

Effect of melatonin on cerebral vasospasm following experimental subarachnoid hemorrhage

OBJECT: The current study was undertaken to determine whether melatonin therapy reverses vasospasm and prevents apoptosis by inhibiting lipid peroxidation in an experimental subarachnoid hemorrhage (SAH) model. MATERIALS AND METHODS: The rabbits were divided into four groups as follows: Group 1, SAH + melatonin (5 mg/kg/i.p. BID) simultaneously with SAH (n = 6); Group 2, SAH + melatonin (5 mg/kg/i.p. BID) treated 2 hours after SAH (n = 6); Group 3, control group (n = 4); Group 4, SAH only (n = 6). Light microscopic examinations of the basilar arteries were performed to demonstrate the pathophysiological changes of the arterial wall with hematoxylin- eosin. Apoptosis: Immunohistology using the ApopTag Peroxidase In Situ Apoptosis Detection Kit was used to demonstrate apoptosis in a cross section of basilary arteries. Apoptotic index was calculated as the number of the immunoreactive nuclei per total number of endothelial cells, and expressed as a percentage. RESULTS: The results of measurements of diameters of the vessels between groups were significantly different (p = 0.028). While basilar arteries of the SAH only group showed 57% constriction, Groups 1 and 2 were calculated as 33 and 26% constriction, respectively, compared with the control group (p < 0.05). And also Groups 1 and 2 showed significant protection of apoptosis compared with Group 4. The difference between the four groups was tested by Kruskal-Wallis test and the significance between the two groups was tested by Mann- Whitney U-test. CONCLUSION: Melatonin with its strong antioxidant effect can prevent SAH-induced vasospasm and apoptosis of endothelial cells of vessels.     

The effects of endothelin antagonist BQ-610 on cerebral vascular wall following experimental subarachnoid hemorrhage and cerebral vasospasm

Abstract. Endothelin, a potent vasoconstrictor, has been found to increase in the cerebrospinal fluid and serum of patients following subarachnoid hemorrhage (SAH) and to play a major role in the development of cerebral vasospasm. The aim of this study is to investigate the role of endothelin-A antagonist BQ-610 in the experimentally performed cerebral vasospasm following SAH. Thirty New Zealand rabbits were divided into three groups (each n = 10): group A, control group; Group B, SAH group; Group C, treatment (endothelin antagonist BQ-610 treated) group. In the study, the rabbits developed vasospasm after injection of intracisternal autolog blood into the cisterna magna. After cerebral vasospasm development, in group C, endothelin antagonist BQ-610 was injected intracisternally. Morphometrically, basilar artery lumen was constricted 25% and 62% compared to the control group (group A) in the endothelin treated group (group C) and the endothelin untreated group (group B), respectively. Histopathological findings of the basilar artery wall confirmed the therapeutic effect of endothelin antagonist in vasospasm development. Endothelin-A receptor antagonist BQ-610 has a therapeutic effect in the cerebral vasospasm following experimentally performed subarachnoid hemorrhage when used intracisternally.     

基底动脉中Caspase3、8的表达与蛛网膜下腔出血后脑血管痉挛的关系

目的探讨天冬氨酸特异性半胱氨酸蛋白酶3、8(Caspase3、8)在蛛网膜下腔出血(SAH)后在基底动脉中的表达及其与脑血管痉挛的关系。方法新西兰大白兔36只,随机分成对照组(n=6)和实验组(n=30),后者再随机分为SAH后1、3、5、7、10d等5个亚组,每亚组各6只。采用枕大池二次注血法建立SAH模型,应用免疫组化和末端脱氧核苷酸转移酶介导的dUTP原位切口末端标记法分别检测基底动脉内皮细胞Caspase3、8表达和凋亡。结果凋亡细胞在实验组SAH后第1天出现,第7天凋亡水平达到最高。实验组Caspase3、8表达水平明显高于与对照组(P<0.05)。Caspase3、8的表达在SAH后第1天就可观察致到,第5天和第7天出现强烈表达,第l0天表达明显减弱。结论本结果提示在兔脑血管痉挛的基底动脉中存在细胞凋亡;Caspase3、8可能参与了SAH后脑血管痉挛的发生和发展。     

促红细胞生成素缓解蛛网膜下腔出血后脑血管痉挛的实验研究

目的 研究早期全身使用促红细胞生成素(EPO)对蛛网膜下腔出血(SAH)后脑血管痉挛(CVS)的作用并探索其作用机理. 方法 将30只雄性新西兰白兔按照随机数字表法等分为5组:(1)空白组;(2)对照组;(3)SAH组;(4)SAH+安慰剂组;(5)SAH+重组人促红细胞生成素(rHuEPO)组.后三组采用枕大池注血法建立兔SAH模型.注血后48 h采用灌注同定法处死动物,留取基底动脉标本.通过测定基底动脉血管横截面积判断有无CVS,并用原位细胞凋亡检测法(TUNEL)检测血管内皮细胞凋亡情况. 结果 基底动脉横截面积测定的结果 提示空白组和对照组、SAH组和SAH+安慰剂组比较,差异无统计学意义(p>0.05);SAH组和SAH+安慰剂组较空白组和对照组明显缩小,差异有统计学意义(P<0.05)SAH+rHuEPO组较SAH组和SAH+安慰剂组明显增大,差异有统计学意义(P<0.05).但小于空白组和对照组.TUNEL染色显示SAH+rHuEPO组血管内皮细胞凋亡程度较SAH组和SAH+安慰剂组减轻,差异有统计学意义(P<0.05). 结论 早期全身使用rHuEPO能减少兔SAH模型基底动脉血管内皮细胞凋亡并部分缓解CVS.     

Cilostazol attenuates cerebral vasospasm after experimental subarachnoid hemorrhage

Abstract

Background and purpose: Cerebral vasospasm is a major cause of morbidity and mortality in patients with subarachnoid hemorrhage (SAH). Cilostazol, a selective inhibitor of phosphodiesterase 3, is a peripheral vasodilator, an anti-inflammatory, and causes antiplatelet aggregation. We investigated these effects on cerebral vasospasm after rat SAH.

Methods: Thirty-eight Sprague–Dawley rats were randomly divided into three groups: SAH + normal feed (SAH group; n=14), SAH + feed containing 0·1% cilostazol (cilostazol group; n=12) and sham-operated rats (sham group; n=12). The basilar arteries (BA) of all groups were analysed by measuring wall thickness, internal luminal perimeter and cross-sectional area on day 7. Immunohistochemical study with RM-4, an anti-rat macrophage/dendritic cells monoclonal antibody and ultrastructural study with transmission electron microscopy were performed.

Results: Although most animals in the SAH group presented with typical vasospasm, the means of inner perimeter and cross-section area of the BA in the cilostazol group were significantly greater than the SAH group (836 ± 134 μm versus 771 ± 125 μm and 39177 ± 15405 μm² versus 33098 ± 13871 μm², respectively). Wall thickness of the BA in the cilostazol group demonstrated significant decrease, compared with the SAH group (17·4 ± 2·3 versus 21·0 ± 2·7 μm). In immunohistological study, SAH induced an obvious increase in mean perivascular RM-4-positive cell count, whereas cilostazol significantly reduced it by 59%. Ultrastructural study depicted cilostazol markedly attenuating structural deterioration of the vascular wall due to SAH.

Conclusions: This work demonstrates that cilostazol attenuates cerebral vasospasm after SAH in rat, possibly in part due to the anti-inflammatory effect.     

细胞色素C在兔蛛网膜下腔出血后脑血管痉挛中的作用

目的 观察兔蛛网膜下腔出血(SAH)后基底动脉细胞色素C(Cyt-C)的表达规律,以探讨其在细胞凋亡中的作用及与脑血管痉挛(CVS)的关系.方法 36只新西兰大白兔随机分为对照组(6只)和SAH组(30只).SAH组采用枕大池二次注血法建立兔CVS模型,对照组行枕大池二次注入生理盐水.应用苏木精-伊红染色观察基底动脉形态学变化,TUNEL法检测基底动脉上细胞凋亡情况,免疫组化检测基底动脉内皮细胞和平滑肌细胞的Cyt-C表达.结果 对照组基底动脉结构正常,偶见凋亡细胞和Cyt-C表达.SAH组基底动脉出现相应病理学改变,管腔狭窄呈双相期改变;基底动脉上细胞凋亡和Cyt-C表达均在SAH后增多,于第7天达高峰,第10天逐渐下降.与对照组比较,SAH组内各时间点基底动脉直径和Cyt-C表达差异均有统计学意义(P<0.05).结论 兔CVS模型的基底动脉中存在细胞凋亡,Cyt-C是启动细胞凋亡的重要因素,在CVS发生和发展过程中起重要作用.     

Human tissue kallikrein ameliorates cerebral vasospasm in a rabbit model of subarachnoid hemorrhage

Objectives: Cerebral vasospasm (CVS) and early brain injury are major causes of morbidity and mortality following subarachnoid hemorrhage (SAH). We investigated the efficiency of human tissue kallikrein (HTK) to prevent CVS in a rabbit model of SAH.

Methods: Forty-eight Japanese white rabbits were randomly divided into four groups (n = 12 each): control (sham-operated), SAH, SAH + phosphate-buffered saline (PBS, vehicle), and SAH + HTK. Basilar artery (BA) diameters were measured by three-dimensional computed tomography angiography at three time points. Endothelin-1 (ET-1) and nitric oxide (NO) levels in the cerebrospinal fluid (CSF) were assayed 24 h before and 5 and 7 days after SAH. After the last measurement, the animals were killed, and endothelial cell apoptosis was assessed. Bax and Bcl-2 levels in the BA were measured by western blotting.

Results: HTK was found to significantly reduce CVS following SAH in rabbits. Inverse changes were observed in ET-1 and NO levels in the CSF collected from the SAH group. HTK increased levels of NO, which has a vasodilatory effect, but did not affect levels of ET-1, which has a vasoconstrictive effect. CTA revealed that HTK treatment significantly increased BA diameter. Moreover, HTK treatment reduced the number of apoptotic cells following SAH, presumably by increasing and decreasing Bcl-2 and Bax expression, respectively.

Conclusion: HTK ameliorated CVS and inhibited apoptosis in the BA in a rabbit model of SAH.     

High incidence of hyponatremia in patients with ruptured anterior communicating artery aneurysms

Abstract

We studied the incidence and timing of hyponatremia (Na < 135 mEq l~¹) after subarachnoid hemorrhage (SAH) with special reference to ruptured anterior communicating artery (A-com) aneurysms. Hunt and Kosnik (HK) grading, symptomatic vasospasm in A-com aneurysm, and hydrocephalus were analyzed for connections to hyponatremia in 55 patients with ruptured A-com aneurysms, 65 with ruptured internal cerebral artery (ICA) aneurysms, and 49 with ruptured middle cerebral artery (MCA) aneurysms. Hyponatremia occurred in 28 (51%) of 55 patients with A-com aneurysms and in nine (18%) of 49 patients with MCA aneurysms. Severe hyponatremia (Na < 130 mEq^-1) occurred in 16 patients (29%) in the A-com group, four patients (6%) in the ICA group, and three patients (6%) in the MCA group. The A-com aneurysm group had a significantly higher incidence of mild hyponatremia (p < 0.01) and severe hyponatremia (p< 0.001) than other groups. Among A-com cases, hyponatremia occurred significantly more often in HK grade III and IV cases (p < 0.05), in cases with vasospasm (p < 0.001), and in cases with hydrocephalus (p < 0.01). Respective days of onset for symptomatic vasospasm and for hyponatremia were day 7.6 ±4.4 and day 10.6± 5.8 following SAH, representing a 3-day delay for hyponatremia (p<0.05). In most patients hyponatremia resolved within 28 days following SAH. Hyponatremia occurred more often with A-com aneurysms, possibly because of vasospasm around the A-com or hydrocephalus causing hypothalamic dysfunction. Since hypervolemic therapy can cause hyponatremia, particularly careful observation is required during such therapy in patients with A-com aneurysm. [Neurol Res 2000; 22: 151-155     

High-Dose Simvastatin Is Effective in Preventing Cerebral Vasospasm after Aneurysmal Subarachnoid Hemorrhage: A Prospective Cohort Study in Korean Patients

ObjectiveThe goal of this study was to assess the effect of high-dose simvastatin on cerebral vasospasm and its clinical outcome after aneurysmal subarachnoid hemorrhage (SAH) in Korean patients.MethodsThis study was designed as a prospective observational cohort study. Its subjects were aneurysmal SAH patients who had undergone aneurysm clipping or coiling. They were assigned to 1 of 3 groups : the 20 mg, 40 mg, and 80 mg simvastatin groups. The primary end-point was the occurrence of symptomatic vasospasm. The clinical outcome was assessed with the modified Rankin Scale (mRS) score after 1 month and 3 months. The risk factors of the development of vasospasm were assessed by logistic regression analysis.ResultsNinety nine patients with aneurysmal SAH were treated and screened. They were sequentially assigned to the 20 mg (n=22), 40 mg (n=34), and 80 mg (n=31) simvastatin groups. Symptomatic vasospasm occurred in 36.4% of the 20 mg group, 8.8% of the 40 mg group, and 3.2% of the 80 mg group (p=0.003). The multiple logistic regression analysis showed that poor Hunt-Hess grades (OR=5.4 and 95% CI=1.09-26.62) and high-dose (80 mg) simvastatin (OR=0.09 and 95% CI=0.1-0.85) were independent factors of symptomatic vasospasm. The clinical outcomes did not show a significant difference among the three groups.ConclusionThis study demonstrated that 80 mg simvastatin treatment was effective in preventing cerebral vasospasm after aneurysmal SAH, but did not improve the clinical outcome in Korean patients.     

Caspase inhibitors prevent endothelial apoptosis and cerebral vasospasm in dog model of experimental subarachnoid hemorrhage.

Apoptosis in the endothelium of major cerebral arteries may play a role in the initiation and maintenance of cerebral vasospasm after subarachnoid hemorrhage (SAH). We tested the therapeutic effect of caspase inhibitors on endothelial apoptosis and on cerebral vasospasm in an established dog double-hemorrhage model. Thirty-one mongrel dogs were divided into five groups: control; SAH; SAH treated with vehicle [DMSO]; SAH treated with Ac-DEVD-CHO [a specific caspase-3 inhibitor]; and SAH treated with Z-VAD-FMK [a broad caspase inhibitor]. The inhibitors (100 microM) were injected into the cisterna magna daily from Day 0 through Day 3. Angiography was performed on Day 0 and Day 7. Histology, TUNEL staining, and immunohistochemistry were conducted on basilar arteries collected on Day 7 after SAH. Positive staining of TUNEL, poly(ADP)-ribose polymerase (PARP), caspase-3, and caspase-8 was observed in the endothelial cells of the spastic arteries. Double fluorescence labeling demonstrated co-localization of TUNEL with caspase-3 and TNFalpha receptor-1 (TNFR1). Ac-DEVD-CHO and Z-VAD-FMK prevented endothelial apoptosis and reduced angiographic vasospasm. The mechanism of apoptosis in endothelial cells involves TNFR1 and the caspase-8 and caspase-3 pathways. Caspase inhibitors may have potential in the treatment of cerebral vasospasm.     

Endoscopic technique: A new model of subarachnoid hemorrhage in rats

Abstract

It has become increasingly evident that the pathophysiology of cerebral vasospasm following subarachnoid hemorrhage (SAH) which described the ischemic consequences of cerebral arterial constriction is complex and multifactorial. In an attempt to study cerebral vasospasm, numerous investigators have used experimental animal models that resemble cerebral vasospasm in humans. No ideal model for SAH has been found as yet, and hence the quest for such a model continues. We developed an endoscopic technique that permits a direct vision of internal carotid artery and puncturing the artery to provoke SAH. This model will closely reflect the clinical setting of an aneurysm rupture. The onset of SAH was characterized by a sudden decrease of cerebral blood flow (CBF) and cerebral blood volume (CBV) by at least 40% in the first 20 min. Following this initial drop, there was an increase in the CBF and the CBV, however, they remained significantly below the base line values, at the end of 1 h. This study describes a new model of SAH in rat that simulates the clinical phenomenon of ruptured intracranial aneurysm that also produces cerebral vasospasm. [Neurol Res 2001; 23: 627-630]     

Cerebrospinal fluid membrane-bound tissue factor and myelin basic protein in the course of vasospasm after subarachnoid hemorrhage

Abstract

No marker that predicts accurately the time of occurrence of cerebral vasospasm due to subarachnoid hemorrhage (SAH) has been reported. In the present study, membrane-bound tissue factor (mTF) and myelin basic protein (MBP) concentrations in cerebrospinal fluid (CSF) were evaluated as a predictor of the time of occurrence of cerebral vasospasm. The mTF and MBP concentrations were measured in the CSF from 28 patients with SAH due to ruptured aneurysm. Serial assays were performed from day 4 to day 14 after SAH. CSF mTF and MBP concentrations from days 5 to 9 correlated with the volume of cerebral infarction due to vasospasm and outcome three months after SAH. From the serial assays, CSF mTF measurements predicted the time of occurrence and severity and irreversibility of symptoms due to vasospasm. In conclusion, CSF mTF is predictive of the occurrence and the recovery of cerebral vasospasm, while CSF MBP is only an indicator of severity of brain damage due to vasospasm. [Neurol Res 2001; 23: 715-720]     

Changes in the cerebrospinal fluid lipid profile following subarachnoid hemorrhage in a closed cranium model: Correlations to cerebral vasospasm,neuronal cell death and Interleukin-6 synthesis. A pilot study

BackgroundPhospholipids and sphingolipids are cell membrane components, that participate in signaling events and regulate a wide variety of vital cellular processes. Sphingolipids are involved in ischemic stroke pathophysiology. Throughout cleavage of membrane sphingomyelin by sphingomyelinase in stroke patients, it results in increased Ceramide (Cer) levels in brain tissue. Different studies showed the evidence that sphingomyelinase with Cer production induces expression of interleukin (IL)-6 and have vasoconstrictive proprieties. With this study, we intend to evaluate cerebrospinal fluid (CSF) lipid profile changes in a rabbit closed cranium subarachnoid hemorrhage (SAH) model.MethodsA total of 14 New Zealand white rabbits were randomly allocated either to SAH or sham group. In the first group SAH was induced by extracranial-intracranial shunting from the subclavian artery into the cisterna magna. Intracranial pressure (ICP) and arterial blood pressure were continuously monitored. Digital subtraction angiography of the basilar artery, CSF and blood samples were performed at day 0 pre SAH and on day 3 post SAH. The amount of IL-6 and various lipids in CSF were quantified using ELISA and Liquid Chromatography-Mass Spectrometry respectively. Cell death was detected in bilateral basal cortex, hippocampus (CA1 and CA3) using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL).ResultsSAH Induction led to acute increase of ICP and increased delayed cerebral vasospasm (DCVS). At follow up CSF IL-6 levels showed a significant increase compared to baseline. Between baseline and follow up there were no significant differences in any of the measured CSF Lipids irrespective of subgroups. No relevant correlation was found between IL-6 and any of the sphingolipids. We found a correlation between baseline and follow up for the phospholipids phosphatidylethanolamine and phosphatidylcholine.ConclusionsNeuronal apoptosis, DCVS and IL-6 seems not to be related to changes in CSF lipid profiles except for PEA and PC in a rabbit closed cranium SAH model.     

蛛网膜下腔血性与非血性刺激物对脑血管影响的组织学比较

目的通过对蛛网膜下腔血性、非血性刺激物对脑血管影响的比较,探讨蛛网膜下腔出血(SAH)后迟发性脑血管痉挛(DCVS)的发病机制。方法将40只新西兰白兔随机分为5组:假手术组、非抗凝自体动脉血组、抗凝自体动脉血组、Kaoline(高岭土)组和失活细菌组,每组8只。假手术组动物仅做枕大池假穿刺;非抗凝血组动物采用经枕大池二次注血法制作DCVS模型;抗凝自体动脉血组用肝素处理后的自体动脉血代替非抗凝血行枕大池二次注血;Kaoline组和失活细菌组经枕大池穿刺分别注入15%Kaoline悬浊液(0.25ml/kg)、失活细菌悬浊液(3×1010个/ml;0.25ml/kg)。各组受试动物在7d时用4%多聚甲醛灌注处死,将脑组织连同基底动脉及其分支取出行HE染色、免疫组化检测TNF-α供组织学研究。结果与假手术组基底动脉血管形态相比,非抗凝血组、Kaoline组和失活细菌组均有不同程度的血管痉挛,抗凝血组无明显血管痉挛。TNF-α表达随血管痉挛程度加重而增加。结论蛛网膜下腔内不同刺激物导致与SAH后DCVS相同的病理改变提示:蛛网膜下腔内刺激物所致血管局部的过度炎症反应可能是导致血管痉挛发生的重要原因。     

Improved rat model for cerebral vasospasm studies

Abstract

While the rat has been used extensively in subarachnoid hemorrhage (SAH)-cerebral vasospasm studies, concerns exist whether this animal represents a usable model because its time course and pattern of cerebral vasospasm following SAH is not comparable to that observed in man. At present, our knowledge of the rat model is based almost exclusively on studies using a 'single hemorrhage' method. Since there is a positive correlation between severity of cerebral vasospasm, and volume of subarachnoid blood, an obvious question is whether the rat will show modifications in vascular responses when insulted by a second SAH. Here, an SAH was produced in rats using a 'double hemorrhage' method. Following SAH, cerebral arteries showed pathological alterations, significant decreases in luminal perimeter, and increases in arterial wall thickness, over a 7-day post-SAH period. The above vascular features are considered to be indicative of cerebral vasospasm and their presence over a 7-day post-SAH period represents a significant time extension when compared to a single hemorrhage. These modified vascular responses made the double hemorrhaged rat a much-improved animal model. [Neurol Res 2001; 23: 761-766]     

Comparison between one- and two-hemorrhage models of cerebral vasospasm in rabbits

Injection of blood into the cisterna magna is one of the most frequently used methods to produce subarachnoid hemorrhage (SAH) models in animals. Although the two-hemorrhage model of vasospasm is frequently used in canine and rat models, most studies with rabbits only use the one-hemorrhage model. In the present study, we accomplished a side-by-side comparison between one- and two-hemorrhage models in rabbits. A total of 38 rabbits were randomly divided into three groups, i.e. control group (n = 5), one (n = 15)- and two (n = 18)-hemorrhage model groups. The degree of cerebral vasospasm, the time course of cerebral vasospasm, the clinical behavior, and the residual amount of subarachnoid blood clots were measured on days 3, 5 and 7 after the establishment of the models. Compared with one-hemorrhage model, the time course of vasospasm in the two-hemorrhage model was more coincident with that observed in humans, produced more severe vasospasm after SAH, and had an acceptable low mortality. In conclusion, the two-hemorrhage model in rabbits is more appropriate than the one-hemorrhage model for the research on SAH or cerebral vasospasm, and thus can be used for the investigation of the mechanisms of and therapeutic approaches for cerebral vasospasm.     

Role of p53 and apoptosis in cerebral vasospasm after experimental subarachnoid hemorrhage.

Our previous studies indicate that apoptosis in endothelial cells of major cerebral arteries contributes to cerebral vasospasm after subarachnoid hemorrhage (SAH). This study examined the pathologic roles of tumor suppressor p-53 in cerebral vasospasm using an established dog double-hemorrhage model. Twenty mongrel dogs were divided into four groups: (1) control, (2) SAH, (3) SAH+DMSO (vehicle), and (4) SAH+pifithrin-alpha (PFT) (p53 inhibitor). The p53 inhibitor (200 nmol/L) was injected into the cisterna magna daily from Day 0 through Day 3. Angiogram was performed on Day 0 and Day 7. Western blot, cell proliferation assay, histology, and TUNEL staining were conducted on the basilar arteries collected on Day 7 after SAH. The arterial diameter on Day 7 was 42%+/-4%, 40%+/-5%, and 59%+/-4% for SAH, SAH+DMSO, and SAH+PFT, respectively. In addition, positive staining of TUNEL and increased protein expression of p53, Bax, and PCNA in the basilar artery were observed on Day 7. PFT suppressed apoptosis in endothelial cells and proliferation in smooth muscle cells, and attenuated angiographic vasospasm. In conclusion, p53 may be a key factor in endothelial apoptosis and smooth muscle proliferation after SAH. Inhibition of p53 may potentially reduce or even prevent cerebral vasospasm.     

Neutrophil activation in acute human central nervous system injury

Abstract

Endothelial cell dysfunction may contribute to cerebral vasospasm and aggravation of ischemic brain damage following subarachnoid hemorrhage (SAH). It has been suggested that oxyhemoglobin derived from subarachnoid blood clots might be a prime candidate for cerebral vasospasm. In this study, cisternal bloody cerebrospinal fluid (bCSF) was collected from SAH patients four and seven days after aneurysmal rupture, and the effects of bCSF on the cell growth and intracellular calcium ion ([Ca²⁺]_i) dynamics were investigated in cultured human umbilical vein endothelial cells. CSF collected from patients undergoing other intracranial surgeries was used as a control. Pre-treatment with bCSF4 significantly facilitated cell proliferation and DNA synthesis in the cultured endothelial cells, and significantly enhanced histamine- induced [Ca²⁺]_i increase, while acute treatment of the bCSF elicited no [Ca²⁺]_i change. Pre-treatment with interleukin-1β showed a similar significant enhancement of the histamine-induced [Ca²⁺]_i response, while pre-treatment with high concentrations of serum or interleukin-6 did not change the [Ca²⁺]_i response. It is concluded that bCSF collected from SAH patients contains some substances which enhance endothelial cell proliferation and sensitivity to inflammatory mediator. [Neurol Res 2000; 22: 588-596]