Effect of cilostazol on delayed cerebral vasospasm after subarachnoid hemorrhage in rats: Evaluation using black blood magnetic resonance imaging

Effects of New-Generation Antiepileptic Drug Prophylaxis on Delayed Neurovascular Events After Aneurysmal Subarachnoid Hemorrhage

Neuroelectric disruptions such as seizures and cortical spreading depolarization may contribute to the development of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH). However, effects of antiepileptic drug prophylaxis on outcomes remain controversial in SAH. The authors investigated if prophylactic administration of new-generation antiepileptic drugs levetiracetam and perampanel was beneficial against delayed neurovascular events after SAH. This was a retrospective single-center cohort study of 121 consecutive SAH patients including 56 patients of admission World Federation of Neurological Surgeons grades IV - V who underwent aneurysmal obliteration within 72 h post-SAH from 2013 to 2021. Prophylactic antiepileptic drugs differed depending on the study terms: none (2013 - 2015), levetiracetam for patients at high risks of seizures (2016 - 2019), and perampanel for all patients (2020 - 2021). The 3rd term had the lowest occurrence of delayed cerebral microinfarction on diffusion-weighted magnetic resonance imaging, which was related to less development of DCI. Other outcome measures were similar among the 3 terms including incidences of angiographic vasospasm, computed tomography-detectable delayed cerebral infarction, seizures, and 3-month good outcomes (modified Rankin Scale 0 - 2). The present study suggests that prophylactic administration of levetiracetam and perampanel was not associated with worse outcomes and that perampanel may have the potential to reduce DCI by preventing microcirculatory disturbances after SAH. Further studies are warranted to investigate anti-DCI effects of a selective α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor antagonist perampanel in SAH patients in a large-scale prospective study.

Real-world data of clazosentan in combination therapy for aneurysmal subarachnoid hemorrhage: a multicenter retrospective cohort study

Aneurysmal subarachnoid hemorrhage (aSAH) may lead to cerebral vasospasm, significantly associated with morbidity and mortality. In double-blind, placebo-controlled phase 3 studies, clazosentan reduces cerebral vasospasm-related morbidity and all-cause mortality in patients with aSAH. There are no reports about the clinical efficacy of clazosentan combination therapy with some other drugs. Initially, we explored the efficacy of clazosentan combination therapy with cilostazol, statin, and antiepileptic drugs. Subsequently, we assessed the add-on effect of fasudil to clazosentan combination therapy for aSAH patients. This multicenter, retrospective, observational cohort study included Japanese patients with aSAH between June 2022 and March 2023. The primary outcome was the ordinal score on the modified Rankin Scale (mRS; range, 0-6, with elevated scores indicating greater disability) at discharge. Among the 47 cases (women 74.5%; age 64.4 ± 15.0 years) undergoing clazosentan combination therapy, 29 (61.7%) resulted in favorable outcomes. Overall, vasospasm occurred in 16 cases (34.0%), with four cases (8.5%) developing vasospasm-related delayed cerebral ischemia (DCI). Both hypotension and vasospasm-related DCI were related to unfavorable outcome at discharge. Fasudil were added in 18 (38.3%) cases. Despite adding fasudil to clazosentan combination therapy, the incidence of aSAH-related vasospasm did not decrease. Added-on fasudil to combination therapy related to pulmonary edema, vasospasm, and vasospasm-related DCI, and unfavorable outcomes. Clazosentan combination therapy could potentially result in favorable outcomes for aSAH patients to prevent post-aSAH vasospasm-related DCI. The add-on effect of fasudil to combination therapy did not demonstrate a significant impact in reducing aSAH-related vasospasm or improving outcomes at discharge.

Effect of Cilostazol on Delayed Cerebral Infarction in Aneurysmal Subarachnoid Hemorrhage Using Explainable Predictive Modeling

The studies interpreting DCI, a complication of SAH, and identifying correlations are very limited. This study aimed to investigate the effect of cilostazol on ACV and DCI after coil embolization for ruptured aneurysms (n = 432). A multivariate analysis was performed and explainable artificial intelligence approaches were used to analyze the contribution of cilostazol as a risk factor on the development of ACV and DCI with respect to global and local interpretation. The cilonimo group was significantly lower than the nimo group in ACV (13.5% vs. 29.3; p = 0.003) and DCI (7.9% vs. 20.7%; p = 0.006), respectively. In a multivariate logistic regression, the odds ratio for DCI for the cilonimo group, female sex, and aneurysm size was 0.556 (95% confidence interval (CI), 0.351-0.879; p = 0.012), 3.713 (95% CI, 1.683-8.191; p = 0.001), and 1.106 (95% CI, 1.008-1.214; p = 0.034). The risk of a DCI occurrence was significantly increased with an aneurysm size greater than 10 mm (max 80%). The mean AUC of the XGBoost and logistic regression models was 0.94 ± 0.03 and 0.95 ± 0.04, respectively. Cilostazol treatment combined with nimodipine could decrease the prevalence of ACV (13.5%) and DCI (7.9%) in patients with aSAH.

Cilostazol Administration for Subarachnoid Hemorrhage: A Meta-analysis of Randomized Controlled Trials

INTRODUCTION

The efficacy of cilostazol administration to treat subarachnoid hemorrhage remains controversial. We conduct a systematic review and meta-analysis to explore the influence of cilostazol administration on treatment efficacy for subarachnoid hemorrhage.

METHODS

We have searched PubMed, Embase, Web of science, EBSCO, and Cochrane Library databases through July 2020 for randomized controlled trials assessing the effect of cilostazol administration in patients with subarachnoid hemorrhage. This meta-analysis is performed using the random-effect model.

RESULTS

Four randomized controlled trials involving 405 patients were included in the meta-analysis. Overall, compared with control group for subarachnoid hemorrhage, cilostazol intervention can significantly reduce symptomatic vasospasm (odds ratio [OR], 0.35; 95% confidence interval [CI], 0.21-0.60; P = 0.0001) and cerebral infarction (OR, 0.40; 95% CI, 0.22-0.73; P = 0.003) and improve no or mild angiographic vasospasm (OR, 2.01; 95% CI, 1.19-3.42; P = 0.01) and an mRS score of 2 or less (OR, 2.70; 95% CI, 1.09-6.71; P = 0.03), but revealed no obvious influence on severe angiographic vasospasm (OR, 0.53; 95% CI, 0.27-1.02; P = 0.06). There were no increase in adverse events (OR, 1.17; 95% CI, 0.54-2.52; P = 0.69), hemorrhagic events (OR, 0.62; 95% CI, 0.06-6.27; P = 0.69), and cardiac events (OR, 2.14; 95% CI, 0.44-10.27; P = 0.34) after the cilostazol intervention than control intervention.

CONCLUSIONS

Cilostazol treatment may be effective to treat subarachnoid hemorrhage in the terms of symptomatic vasospasm, cerebral infarction, no or mild angiographic vasospasm, and an mRS score of 2 or less.

Effects of cilostazol treatment for patients with aneurysmal subarachnoid hemorrhage: A meta-analysis of 14 studies

OBJECTIVE

To perform an updated meta-analysis to comprehensively assess the efficacy and safety of cilostazol in preventing aneurysmal subarachnoid hemorrhage (SAH)-related secondary complications.

METHODS

Electronic databases of PubMed, the Cochrane library, CNKI and Wanfang were searched on August 2021. Pooled odds ratio (OR) and standardized mean difference (SMD) were calculated for dichotomous and continuous outcomes, respectively.

RESULTS

A total of 14 studies [comprising 18,726 aneurysmal SAH patients (6654 in the cilostazol group and 12,072 in the control group)] performed in Japan or China were included. Compared with the control group, cilostazol treatment significantly reduced the median cerebral artery (SMD = -0.49; p < 0.001), improved the therapeutic efficacy (OR = 2.37; p = 0.009), decreased the incidence of symptomatic vasospasm/delayed cerebral ischemia (OR = 0.42; p < 0.001), severe angiographic vasospasm (OR = 0.54; p < 0.001), new cerebral infarction (OR = 0.33; p < 0.001), poor outcomes (OR = 0.86; p = 0.001), mortality (OR = 0.62; p < 0.001) and increased the incidence of no or mild angiographic vasospasm (OR = 1.94; p = 0.004), but did not induce more adverse events (OR = 1.08; p = 0.871). The mechanism of cilostazol treatment was to inhibit the production of tenascin-C (SMD = -1.46; p < 0.001). These results were hardly changed by subgroup analysis.

CONCLUSION

This meta-analysis indicates cilostazol may be an effective and safe drug for aneurysmal SAH patients. However, further trials involving other world populations are required to demonstrate the generalization of treatment effects of cilostazol.

Cilostazol administration for subarachnoid hemorrhage: A meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of cilostazol administration to treat subarachnoid hemorrhage remains controversial. We conduct a systematic review and meta-analysis to explore the influence of cilostazol administration on treatment efficacy for subarachnoid hemorrhage.

METHODS

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through July 2020 for randomized controlled trials (RCTs) assessing the effect of cilostazol administration in patients with subarachnoid hemorrhage. This meta-analysis is performed using the random-effect model.

RESULTS

Four RCTs involving 405 patients were included in the meta-analysis. Overall, compared with control group for subarachnoid hemorrhage, cilostazol intervention can significantly reduce symptomatic vasospasm (OR = 0.35; 95% CI = 0.21 to 0.60; P = 0.0001) and cerebral infarction (OR = 0.40; 95% CI = 0.22 to 0.73; P = 0.003), as well as improve no or mild angiographic vasospasm (OR = 2.01; 95% CI = 1.19 to 3.42; P = 0.01) and mRS score ≤ 2 (OR = 2.70; 95% CI = 1.09 to 6.71; P = 0.03), but revealed no obvious influence on severe angiographic vasospasm (OR = 0.53; 95% CI = 0.27 to 1.02; P = 0.06). There were no increase in adverse events (OR = 1.17; 95% CI = 0.54 to 2.52; P = 0.69), hemorrhagic events (OR = 0.62; 95% CI = 0.06 to 6.27; P = 0.69) and cardiac events (OR = 2.14; 95% CI = 0.44 to 10.27; P = 0.34) after the cilostazol intervention than control intervention.

CONCLUSIONS

Cilostazol treatment may be effective to treat subarachnoid hemorrhage in the terms of symptomatic vasospasm, cerebral infarction, no or mild angiographic vasospasm and mRS score ≤ 2.

Role of Cilostazol in Prevention of Vasospasm After Aneurysmal Subarachnoid Hemorrhage-A Systematic Review, Meta-Analysis, and Trial Sequential Analysis

OBJECTIVE

Cerebral vasospasm is a common complication after aneurysmal subarachnoid hemorrhage (aSAH). Many drugs have been tried to mitigate cerebral vasospasm and delayed cerebral ischemia. Cilostazol, a selective inhibitor of phosphodiesterase 3, is a promising agent in preventing cerebral vasospasm and delayed cerebral ischemia after aSAH. The objective of this article was to ascertain the effect of cilostazol on cerebral vasospasm after aSAH by performing meta-analysis and trial sequential analysis.

METHODS

A systematic search of the literature was performed, and all the eligible randomized controlled trials were included in the meta-analysis and trial sequential analysis.

RESULTS

A total of 454 articles were identified using the search criteria. Six articles were selected for systematic review and the 4 randomized controlled trials were included in the meta-analysis. The pooled odds ratio for symptomatic vasospasm, new-onset infarct, and angiographic vasospasm was 0.35 (95% confidence interval [CI], 0.21-0.59; P < 0.0001), 0.38 (95% CI, 0.21-0.66; P = 0.0007) and 0.49 (95% CI, 0.31-0.80; P = 0.004), respectively. The pooled risk ratio for unfavorable outcome was 0.52 (95% CI, 0.37-0.74; P = 0.0003).

CONCLUSIONS

Cilostazol decreases the prevalence of symptomatic vasospasm, new-onset infarct, and angiographic vasospasm when administered after aSAH. Trial sequential analysis increased the precision of our results because the defined thresholds of effect were met by the available studies. However, further studies involving patients from other geographic areas are required to confirm the generalization of the results.

The role of immune inflammation in aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating disease, which mainly caused by the rupture of an intracranial aneurysm. Clinical trials have demonstrated that cerebral vasospasm (CVS) is not the sole contributor to delayed cerebral ischemia (DCI) and poor outcomes in patients with aSAH. Currently, accumulating evidence suggests that early brain injury (EBI), which occurs within 72 h after the onset of aSAH, lays the foundation for subsequent pathophysiological changes and poor outcomes of patients. The pathological mechanisms of EBI mainly include increased intracranial pressure, oxidative stress, neuroinflammation, blood-brain barrier (BBB) disruption, cerebral edema and cell death. Among them, the brain immune inflammatory responses involve a variety of immune cells and active substances, which play an important role in EBI after aSAH and may be related to DCI and long-term outcomes. Thus, attention should be paid to strategies targeting cerebral immune inflammatory responses. In this review, we discuss the role of immune inflammatory responses in the occurrence and development of aSAH, as well as some inflammatory biomarkers related to CVS, DCI, and aSAH outcomes. In addition, we also summarize the potential therapeutic drugs that target cerebral immune inflammatory responses for patients with aSAH in current research.

Efficacy and safety of cilostazol-nimodipine combined therapy on delayed cerebral ischaemia after aneurysmal subarachnoid haemorrhage: a prospective, randomised, double-blinded, placebo-controlled trial protocol

INTRODUCTION

Delayed cerebral ischaemia (DCI) due to cerebral vasospasm (cVS) remains the foremost contributor to morbidity and mortality following aneurysmal subarachnoid haemorrhage (aSAH). Past efforts in preventing and treating DCI have failed to make any significant progress. To date, our most effective treatment involves the use of nimodipine, a calcium channel blocker. Recent studies have suggested that cilostazol, a platelet aggregation inhibitor, may prevent cVS. Thus far, no study has evaluated the effect of cilostazol plus nimodipine on the rate of DCI following aSAH.

METHODS AND ANALYSIS

This is a multicentre, double-blinded, randomised, placebo-controlled superiority trial investigating the effect of cilostazol on DCI. Data concerning rates of DCI, symptomatic and radiographic vasospasm, length of intensive care unit stay, and long-term functional and quality-of-life (QoL) outcomes will be recorded. All data will be collected with the aim of demonstrating that the use of cilostazol plus nimodipine will safely decrease the incidence of DCI, and decrease the rates of both radiographic and symptomatic vasospasm with subsequent improvement in long-term functional and QoL outcomes when compared with nimodipine alone.

ETHICS AND DISSEMINATION

Ethical approval was obtained from all participating hospitals by the Ascension Providence Hospital Institutional Review Board. The results of this study will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04148105.

Dose-Dependent Inhibitory Effects of Cilostazol on Delayed Cerebral Infarction After Aneurysmal Subarachnoid Hemorrhage

Cilostazol is a selective inhibitor of phosphodiesterase type III that downregulates tenascin-C (TNC), a matricellular protein, which may cause delayed cerebral infarction after aneurysmal subarachnoid hemorrhage (SAH). The authors increased the dosage and evaluated the dose-dependent effects of cilostazol on delayed cerebral infarction and outcomes in SAH patients. This was a retrospective cohort study in a single center. One hundred fifty-six consecutive SAH patients including 67 patients of admission World Federation of Neurological Surgeons grades IV-V who underwent aneurysmal obliteration within 48 h post-SAH from 2007 to 2017 were analyzed. Cilostazol (0 to 300 mg/day) was administered from 1-day post-clipping or post-coiling to day 14 or later. Cilostazol treatment dose-dependently decreased delayed cerebral infarction and tended to improve outcomes, although cilostazol did not affect other outcome measures including angiographic vasospasm. On multivariate analyses, 300 mg/day (100 mg three times) cilostazol independently decreased delayed cerebral infarction and improved 3-month outcomes, but other regimens including 200 mg/day (100 mg twice) cilostazol were not independent prognostic factors. Propensity score-matched analyses showed that the 300 mg/day cilostazol cohort had lower plasma TNC levels and a lower incidence of delayed cerebral infarction associated with better outcomes compared with the non-cilostazol cohort. The 300 mg/day cilostazol may improve post-SAH outcomes by reducing plasma TNC levels and delayed cerebral infarction, but not vasospasm. Further studies are warranted to investigate if 300 mg/day cilostazol is more beneficial to post-SAH outcomes than a usual dose of 200 mg/day cilostazol that was demonstrated to be effective in randomized controlled trials.

Therapeutically Targeting Platelet-Derived Growth Factor-Mediated Signaling Underlying the Pathogenesis of Subarachnoid Hemorrhage-Related Vasospasm

INTRODUCTION

Vasospasm accounts for a large fraction of the morbidity and mortality burden in patients sustaining subarachnoid hemorrhage (SAH). Platelet-derived growth factor (PDGF)-β levels rise following SAH and correlate with incidence and severity of vasospasm.

METHODS

The literature was reviewed for studies investigating the role of PDGF in the pathogenesis of SAH-related vasospasm and efficacy of pharmacological interventions targeting the PDGF pathway in ameliorating the same and improving clinical outcomes.

RESULTS

Release of blood under high pressure into the subarachnoid space activates the complement cascade, which results in release of PDGF. Abluminal contact of blood with cerebral vessels increases their contractile response to PDGF-β and thrombin, with the latter upregulating PDGF-β receptors and augmenting effects of PDGF-β. PDGF-β figures prominently in the early and late phases of post-SAH vasospasm. PDGF-β binding to the PDGF receptor-β results in receptor tyrosine kinase domain activation and consequent stimulation of intracellular signaling pathways, including p38 mitogen-activated protein kinase, phosphatidylinositol-3-kinase, Rho-associated protein kinase, and extracellular regulated kinase 1 and 2. Consequent increases in intracellular calcium and increased expression of genes mediating cellular growth and proliferation mediate PDGF-induced augmentation of vascular smooth muscle cell contractility, hypertrophy, and proliferation.

CONCLUSION

Treatments with statins, serine protease inhibitors, and small molecular pathway inhibitors have demonstrated varying degrees of efficacy in prevention of cerebral vasospasm, which is improved with earlier institution.

Inflammation, vasospasm, and brain injury after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) can lead to devastating neurological outcomes, and there are few pharmacologic treatments available for treating this condition. Both animal and human studies provide evidence of inflammation being a driving force behind the pathology of SAH, leading to both direct brain injury and vasospasm, which in turn leads to ischemic brain injury. Several inflammatory mediators that are elevated after SAH have been studied in detail. While there is promising data indicating that blocking these factors might benefit patients after SAH, there has been little success in clinical trials. One of the key factors that complicates clinical trials of SAH is the variability of the initial injury and subsequent inflammatory response. It is likely that both genetic and environmental factors contribute to the variability of patients' post-SAH inflammatory response and that this confounds trials of anti-inflammatory therapies. Additionally, systemic inflammation from other conditions that affect patients with SAH could contribute to brain injury and vasospasm after SAH. Continuing work on biomarkers of inflammation after SAH may lead to development of patient-specific anti-inflammatory therapies to improve outcome after SAH.

Tenascin-C induces prolonged constriction of cerebral arteries in rats

Tenascin-C (TNC), a matricellular protein, is induced in association with cerebral vasospasm after subarachnoid hemorrhage. The aim of this study was to assess the vasoconstrictive effects of TNC and its mechanisms of action on cerebral arteries in vivo. Two dosages (1 and 10μg) of TNC were administered intracisternally to healthy rats, and the effects were evaluated by neurobehavioral tests and India-ink angiography at 24, 48, and 72h after the administration. Western blotting and immunohistochemistry were performed to explore the underlying mechanisms on constricted cerebral arteries after 24h. The effects of toll-like receptor 4 (TLR4) antagonists (LPS-RS), c-Jun N-terminal kinase (JNK), and p38 inhibitors (SP600125 and SB203580) on TNC-induced vasoconstriction were evaluated at 24h. Higher dosages of TNC induced more severe cerebral arterial constriction, which continued for more than 72h. TNC administration also upregulated TLR4, and activated JNK and p38 in the smooth muscle cell layer of the constricted cerebral artery. LPS-RS blocked TNC-induced TLR4 upregulation, JNK and p38 activation, and vasoconstrictive effects. SP600125 and SB203580 abolished TNC-induced TLR4 upregulation and vasoconstrictive effects. TNC may cause prolonged cerebral arterial constriction via TLR4 and activation of JNK and p38, which may upregulate TLR4. These findings suggest that TNC causes cerebral vasospasm and provides a novel therapeutic approach against it.

Effects of cilostazol on cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a multicenter prospective, randomized, open-label blinded end point trial

Object

Cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is a major cause of subsequent morbidity and mortality. Cilostazol, a selective inhibitor of phosphodiesterase 3, may attenuate cerebral vasospasm because of its antiplatelet and vasodilatory effects. A multicenter prospective randomized trial was conducted to investigate the effect of cilostazol on cerebral vasospasm.

Methods

Patients admitted with SAH caused by a ruptured anterior circulation aneurysm who were in Hunt and Kosnik Grades I to IV and were treated by clipping within 72 hours of SAH onset were enrolled at 7 neurosurgical sites in Japan. These patients were assigned to one of 2 groups: the usual therapy group (control group) or the add-on 100 mg cilostazol twice daily group (cilostazol group). The group assignments were done by a computer-generated randomization sequence. The primary study end point was the onset of symptomatic vasospasm. Secondary end points were the onset of angiographic vasospasm and new cerebral infarctions related to cerebral vasospasm, clinical outcome as assessed by the modified Rankin scale, and length of hospitalization. All end points were assessed for the intention-to-treat population.

Results

Between November 2009 and December 2010, 114 patients with SAH were treated by clipping within 72 hours from the onset of SAH and were screened. Five patients were excluded because no consent was given. Thus, 109 patients were randomly assigned to the cilostazol group (n = 54) or the control group (n = 55). Symptomatic vasospasm occurred in 13% (n = 7) of the cilostazol group and in 40% (n = 22) of the control group (p = 0.0021, Fisher exact test). The incidence of angiographic vasospasm was significantly lower in the cilostazol group than in the control group (50% vs 77%; p = 0.0055, Fisher exact test). Multiple logistic analyses demonstrated that nonuse of cilostazol is an independent factor for symptomatic and angiographic vasospasm. The incidence of new cerebral infarctions was also significantly lower in the cilostazol group than in the control group (11% vs 29%; p = 0.0304, Fisher exact test). Clinical outcomes at 1, 3, and 6 months after SAH in the cilostazol group were better than those in the control group, although a significant difference was not shown. There was also no significant difference in the length of hospitalization between the groups. No severe adverse event occurred during the study period.

Conclusions

Oral administration of cilostazol is effective in preventing cerebral vasospasm with a low risk of severe adverse events. Clinical trial registration no. UMIN000004347, University Hospital Medical Information Network Clinical Trials Registry.

Comparison of intrathecal cilostazol and nimodipine treatments in subarachnoid hemorrhage: an experimental study in rabbits

OBJECTIVE

intrathecal administration of calcium channel antagonists has been proposed to reduce cerebral vasospasm (CVS) in animal subarachnoid hemorrhage (SAH) models. Also, delayed CVS treatment model with oral administration of cilostazol can be seen in the literature.

METHODS

in this study, 25 male New Zealand white rabbits were randomly assigned to five groups: control, SAH only, SAH/nimodipine, SAH/cilostazol, SAH/vehicle. The animals' basilar arteries were sectioned from four separate zones and four sections were obtained from each rabbit. Basilar artery luminal section areas were measured by using SPOT for windows Version 4.1 computer program.

RESULTS

basilar artery luminal section areas in SAH/ nimodipine and SAH/ cilostazol groups were significantly higher than SAH only group (P < 0.05).

CONCLUSION

phosphodiesterase 3 inhibitor cilostazol has vasodilatory effects without affecting cerebral blood flow. Nimodipine is a calcium channel blocker and is still used in vasospasm therapy either oral or intravenously. This study demonstrates that prophylactic bolus intrathecal administration of either cilostazol or nimodipine equally prevents SAH-associated CVS in an animal model. We therefore propose that cilostazol is a candidate for clinical trials in the treatment of delayed vasospasm.

Dose-dependent ultrastructural and morphometric alterations after erythropoietin treatment in rat femoral artery vasospasm model

PURPOSE

Cerebral vasospasm is the common cause of poor outcome after aneurysmal subarachnoid hemorrhage (aSAH). Although many agents are experimentally and clinicaly used to protect or recover from vasospasm, an effective neurotherapeutic drug is still missing. Erythropoietin (EPO) is recently a promising candidate. The aim of this study is to investigate the dose-dependent effects of recombinant human EPO (rhEPO) on arterial wall in a rat femoral artery vasospasm model.

METHODS

Thirty two animals were divided into four groups: vasospasm without any treatment (group A), vasospasm +250 IU/kg rhEPO group (group B), vasospasm +500 IU/kg rhEPO group (group C), and control group (group D). Rat femoral artery vasospasm model was used. For groups B and C, 7 days of 250 IU/kg and 500 IU/kg intraperitoneal rhEPO in 0.3 ml saline were administered respectively; and for groups A and D, 0.3 ml saline were administered intraperitoneally without any treatment. After 7 days, histological and morphometric analyses were carried out.

RESULTS

Vasospasm alone group demonstrated the highest vessel wall thicknesses, comparing to other groups (p < 0.001). While for groups B and C, vessel wall thickness values were significantly higher than the control group (p < 0.001), between these two groups, there was no significant difference achieved (p > 0.05).

CONCLUSION

In our study, there was no significant difference between the two rhEPO treatment groups, but rhEPO treatment was shown to be histologically and morphometrically effective in vasospasm. However, if dosage of EPO treatment is augmented, successful results may be achieved.

Cilostazol, a phosphodiesterase inhibitor, attenuates photothrombotic focal ischemic brain injury in hypertensive rats

The aim of this study was to evaluate and compare the effects of anti-platelet agents with different modes of action (cilostazol, aspirin, and clopidogrel) on brain infarction produced by photothrombotic middle-cerebral-artery (MCA) occlusion in male, spontaneously hypertensive rats. Cerebral blood flow (CBF) was measured with laser-Doppler flowmetry in the penumbral cortex. Infarct size was evaluated 24 h after MCA occlusion. The effects of these drugs on infarct size were examined by pretreatment of rats undergoing MCA occlusion. Pretreatment with cilostazol (100 mg/kg) significantly reduced infarct size. In contrast, aspirin (10 mg/kg) and clopidogrel (3 mg/kg) failed to mitigate infarct size, regardless of their apparent inhibitory effects on platelet aggregation. Post-treatment with cilostazol also significantly attenuated the infarct size, associated with improved CBF in the penumbral region. In support of this effect, cilostazol increased nitric oxide (NO) production and prostaglandin-I(2) (PGI(2)) release in cultured human brain microvascular endothelial cells. Cilostazol-induced NO production and PGI(2) release were completely abolished by an NO synthase inhibitor and aspirin, respectively. These findings show that cilostazol reduced brain infarct size due to an improvement in penumbral CBF possibly in association with increased endothelial NO and PGI(2) production.