A novel inhibitor of inflammatory cytokine production (CNI-1493) reduces rodent post-hemorrhagic vasospasm

The Cholinergic Anti-Inflammatory Response and the Role of Macrophages in HIV-Induced Inflammation

Macrophages are phagocytic immune cells that protect the body from foreign invaders and actively support the immune response by releasing anti- and proinflammatory cytokines. A seminal finding revolutionized the way macrophages are seen. The expression of the neuronal alpha7 nicotinic acetylcholine receptor (α7-nAChR) in macrophages led to the establishment of the cholinergic anti-inflammatory response (CAR) in which the activation of this receptor inactivates macrophage production of proinflammatory cytokines. This novel neuroimmune response soon began to emerge as a potential target to counteract inflammation during illness and infection states. Human immunodeficiency virus (HIV)-infected individuals suffer from chronic inflammation that persists even under antiretroviral therapy. Despite the CAR’s importance, few studies involving macrophages have been performed in the HIV field. Evidence demonstrates that monocyte-derived macrophages (MDMs) recovered from HIV-infected individuals are upregulated for α7-nAChR. Moreover, in vitro studies demonstrate that addition of an HIV viral constituent, gp120_IIIB, to uninfected MDMs also upregulates the α7-nAChR. Importantly, contrary to what was expected, activation of upregulated α7-nAChRs in macrophages does not reduce inflammation, suggesting a CAR disruption. Although it is reasonable to consider this receptor as a pharmacological target, additional studies are necessary since its activity seems to differ from that observed in neurons.

Severity of cerebral vasospasm associated with development of collaterals following aneurysmal subarachnoid hemorrhage

Introduction

Cerebral collateral circulation has been studied extensively in ischemic stroke where it has been shown to be a predictor of reperfusion, final infarct size, and outcome. Little is known about the significance of the collaterals in the setting of aneurysmal subarachnoid hemorrhage (aSAH). We sought to evaluate the effect of cerebral vasospasm on the development of cerebral collaterals following aneurysmal subarachnoid hemorrhage and the effects of the latter on delayed cerebral ischemia (DCI).

Methods

We retrospectively evaluated 64 aSAH patients with evidence of DCI between day 5 and 7, enrolled in a prospectively maintained observational cohort study. Angiograms were evaluated by four blinded neurointerventionalists. We compared good collateral grades to poor collateral grades, additionally we compared enrolled individuals with any collaterals versus patients who had no collaterals.

Results

Inter-rater reliability for collateral grades was substantial (weighted kappa 0.632). Mild vasospasm was more frequent in patients with poor collateral grades compared with patients with good collateral grades (32% vs 4% P=0.012). There was no difference between the collateral groups with regards to DCI, functional, or cognitive outcome. Patients adjudicated to have any collaterals were more likely to have severe vasospasm (62% vs 33% P=0.023) and less likely to have mild vasospasm (37% vs 9% P=0.007). In a multivariable model, vasospasm severity remained associated with collateral status, while aneurysm location was not.

Conclusions

The severity of vasospasm following aSAH was associated with the development of collaterals. There was no difference between collateral grades with regards to DCI or outcome.

Anti-inflammatory effect and mechanism of the spirocyclopiperazinium salt compound LXM-15 in rats and mice

OBJECTIVE

This study aimed to investigate the anti-inflammatory effects of a novel spirocyclopiperazinium salt compound LXM-15, and explore the underlying mechanisms.

METHODS

Xylene-induced mouse ear oedema and carrageenan-induced rat paw oedema tests were used to evaluate the anti-inflammatory effects of LXM-15. The protein levels of TNF-α, IL-6, phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) were detected by ELISA or Western blot analysis. Additionally, receptor blocking test was performed to explore the possible target.

RESULTS

Intragastric administration with LXM-15 (2, 1, 0.5 mg/kg in mice, and 6, 3, 1.5 mg/kg in rats) produced distinct anti-inflammatory effects in vivo, the highest inhibition percentage was 60 and 52%, respectively (P < 0.01). Following treatment with LXM-15 (6 mg/kg, i.g.), the levels of TNF-α and IL-6 in the rats paws were attenuated by 40 and 41%; and the phosphorylation of JAK2 and STAT3 was restrained by 35 and 45%, respectively (P < 0.01). All effects of LXM-15 were blocked by pretreatment with methyllycaconitine citrate or tropicamide.

CONCLUSION

This study provides the first report that the spirocyclopiperazinium salt compound LXM-15 displays considerable anti-inflammatory effects. The underlying mechanism may be through activating the peripheral α7 nicotinic acetylcholine receptor and M4 muscarinic acetylcholine receptor, leading to the inhibition of the JAK2/STAT3 signalling pathway, eventually resulting in the reduction of TNF-α and IL-6.

Elevated Systemic IL-6 Levels in Patients with Aneurysmal Subarachnoid Hemorrhage Is an Unspecific Marker for Post-SAH Complications

Background: Aneurysmal subarachnoid hemorrhage (aSAH) is still a fatal and morbid disease, although bleeding aneurysms can be secured in almost all cases. Occurrence of post-SAH complications including cerebral vasospasm, delayed cerebral ischemia, hydrocephalus, epilepsy, and infections are the main determinants of clinical outcome. Hence, it is important to search for early predictors for specific post-SAH complications to treat these complications properly. Both cellular and molecular (cytokines) inflammation play a key role after aSAH during the phase of occurrence of post-SAH complications. Interleukin-6 (IL-6) is a well-known cytokine that has been extensively analyzed in cerebrospinal fluid (CSF) of patients after aSAH, but detailed studies exploring the role of systemic IL-6 in aSAH associated complications and its impact on early clinical outcome prediction are lacking. The current study aims to analyze the systemic IL-6 levels over two weeks after bleeding and its role in post-SAH complications. Methods: We recruited 80 aSAH patients prospectively who underwent peripheral venous blood withdrawal in serum gel tubes. The blood was centrifuged to harvest the serum, which was immediately frozen at −80 °C until analysis. Serum IL-6 levels were quantified using Immulite immunoassay system. Patient records including age, gender, post-SAH complications, aneurysm treatment, and clinical outcome (modified Rankin scale and Glasgow outcome scale) were retrieved to allow different subgroup analysis. Results: Serum IL-6 levels were significantly raised after aSAH compared to healthy controls over the first two weeks after hemorrhage. Serum IL-6 levels were found to be significantly elevated in aSAH patients presenting with higher Hunt and Hess grades, increasing age, and both intraventricular and intracerebral hemorrhage. Interestingly, serum IL-6 was also significantly raised in aSAH patients who developed seizures, cerebral vasospasm (CVS), and chronic hydrocephalus. IL-6 levels were sensitive to the development of infections and showed an increase in patients who developed pneumoniae. Intriguingly, we found a delayed increase in serum IL-6 in patients developing cerebral infarction. Finally, IL-6 levels were significantly higher in patients presenting with poor clinical outcome in comparison to good clinical outcome at discharge from hospital. Conclusion: Serum IL-6 levels were elevated early after aSAH and remained high over the two weeks after initial bleeding. Serum IL-6 was elevated in different aSAH associated complications, acting as a non-specific marker for post-SAH complications and an important biomarker for clinical outcome at discharge.

Heparanase promotes neuroinflammatory response during subarachnoid hemorrhage in rats

BACKGROUND

Heparanase, a mammalian endo-β-D-glucoronidase that specifically degrades heparan sulfate, has been implicated in inflammation and ischemic stroke. However, the role of heparanase in neuroinflammatory response in subarachnoid hemorrhage (SAH) has not yet been investigated. This study was designed to examine the association between heparanase expression and neuroinflammation during subarachnoid hemorrhage.

METHODS

Rats were subjected to SAH by endovascular perforation, and the expression of heparanase was determined by Western blot analysis and immunofluorescence in the ipsilateral brain cortex at 24 h post-SAH. Pial venule leukocyte trafficking was monitored by using intravital microscopy through cranial window.

RESULTS

Our results indicated that, compared to their sham-surgical controls, the rats subjected to SAH showed marked elevation of heparanase expression in the ipsilateral brain cortex. The SAH-induced elevation of heparanase was accompanied by increased leukocyte trafficking in pial venules and significant neurological deficiency. Intracerebroventricular application of a selective heparanase inhibitor, OGT2115, which was initiated at 3 h after SAH, significantly suppressed the leukocyte trafficking and improved the neurological function.

CONCLUSIONS

Our findings indicate that heparanase plays an important role in mediating the neuroinflammatory response after SAH and contributes to SAH-related neurological deficits and early brain injury following SAH.

S100B raises the alert in subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating disease with high mortality and mobility, the novel therapeutic strategies of which are essentially required. The calcium binding protein S100B has emerged as a brain injury biomarker that is implicated in pathogenic process of SAH. S100B is mainly expressed in astrocytes of the central nervous system and functions through initiating intracellular signaling or via interacting with cell surface receptor, such as the receptor of advanced glycation end products. The biological roles of S100B in neurons have been closely associated with its concentrations, resulting in either neuroprotection or neurotoxicity. The levels of S100B in the blood have been suggested as a biomarker to predict the progress or the prognosis of SAH. The role of S100B in the development of cerebral vasospasm and brain damage may result from the induction of oxidative stress and neuroinflammation after SAH. To get further insight into mechanisms underlying the role of S100B in SAH based on this review might help us to find novel therapeutic targets for SAH.

Sulforaphane activates the cerebral vascular Nrf2-ARE pathway and suppresses inflammation to attenuate cerebral vasospasm in rat with subarachnoid hemorrhage

Nrf2-ARE pathway reportedly plays a protective role in several central nervous system diseases. No study has explored the role of the Nrf2-ARE pathway in cerebral vasospasm(CVS) after subarachnoid hemorrhage(SAH). The purpose of the present study was to investigate the activation of the cerebral vascular Nrf2-ARE pathway and to determine the potential role of this pathway in the development of CVS following SAH. We investigated whether the administration of sulforaphane (SFN, a specific Nrf2 activator) modulated vascular caliber, Nrf2-ARE pathway activity, proinflammatory cytokine expression, and clinical behavior in a rat model of SAH. A two-hemorrhage protocol was used to generate an animal model of SAH in male Sprague-Dawley rats. Administration of SFN to these rats following SAH enhanced the activity of the Nrf2-ARE pathway and suppressed the release of proinflammatory cytokines. Vasospasm was markedly attenuated in the basilar arteries after SFN therapy. Additionally, SFN administration significantly ameliorated two behavioral functions disrupted by SAH. These results suggest that SFN has a therapeutic benefit in post-SAH, and this may be due to elevated Nrf2-ARE pathway activity and inhibition of cerebral vascular proinflammatory cytokine expression.

4'-O-β-D-glucosyl-5-O-methylvisamminol, an active ingredient of Saposhnikovia divaricata, attenuates high-mobility group box 1 and subarachnoid hemorrhage-induced vasospasm in a rat model

Background

High-mobility group box 1 (HMGB1) was observed to be an important extracellular mediator involved in vascular inflammation associated with subarachnoid hemorrhage (SAH). This study is of interest to examine the efficacy of 4′-O-β-d-glucosyl-5-O-methylvisamminol (4OGOMV), C₂₂H₂₈O₁₀, on the alternation of cytokines and HMGB1 in an animal model.

Methods

A rodent double hemorrhage SAH model was employed. Administration with 4OGOMV was initiated 1 h after animals were subjected to SAH. Basilar arteries (BAs) were harvested and cortexes examined for HMGB1 mRNA, protein expression (Western blot) and monocyte chemoattractant protein-1 (MCP-1) immunostaining. Cerebrospinal fluid samples were collected to examine IL-1β, IL-6, IL-8 and MCP-1 (rt-PCR).

Results

Morphological findings revealed endothelial cell deformity, intravascular elastic lamina torture, and smooth muscle necrosis in the vessels of SAH groups. Correspondently, IL-1β, IL-6 and MCP-1 in the SAH-only and SAH-plus vehicle groups was also elevated. 4OGOMV dose-dependently reduced HMGB1 protein expression when compared with the SAH groups.(p < 0.01) Likewise, 400 μg/kg 4OGOMV reduced IL-1β, MCP-1 and HMGB1 mRNA levels as well as MCP-1(+) monocytes when compared with the SAH groups..

Conclusion

4OGOMV exerts its neuro-protective effect partly through the dual effect of inhibiting IL-6 and MCP-1 activation and also reduced HMGB1 protein, mRNA and MCP-1(+) leukocytes translocation. This study lends credence to validating 4OGOMV as able to attenuate pro-inflammatory cytokine mRNA, late-onset inflammasome, and cellular basis in SAH-induced vasospasm.

Risk Factors for Cerebral Vasospasm Following Aneurysmal Subarachnoid Hemorrhage: A Review of the Literature

OBJECTIVE

To examine the literature on risk factors for cerebral vasospasm (CV), one of the most serious complications following aneurysmal subarachnoid hemorrhage (SAH), with special reference to the definition of CV.

METHODS

Using standard search engines, including PubMed, the medical literature on risk factors for CV after SAH was reviewed, and the best definition representative of CV was searched.

RESULTS

Severe SAH evident on computed tomography scan was the only consistent risk factor for CV after SAH. Effects of risk factors on CV, including age, clinical grade, rebleeding, intraventricular or intracerebral hemorrhage on computed tomography scan, acute hydrocephalus, aneurysm site and size, leukocytosis, interleukin-6 level, and cardiac abnormalities, appeared to be associated with the severity of SAH rather than each having a direct effect. Cigarette smoking, hypertension, and left ventricular hypertrophy on electrocardiogram were associated with CV without any relationship to SAH severity. With regard to parameters representative of CV, the grade of angiographic vasospasm (i.e., the degree of arterial narrowing evident on angiography) was the most adequate. Nevertheless, few reports on the risk factors associated with angiographic vasospasm grade have been reported to date.

CONCLUSIONS

Severe SAH evident on computed tomography scan appears to be a definite risk factor for CV after SAH, followed by cigarette smoking, hypertension, and left ventricular hypertrophy on electrocardiogram. To understand the pathogenesis of CV, further studies on the relationships between risk factors, especially factors not related to the severity of SAH, and angiographic vasospasm grade are necessary.

Preconditioning with pitavastatin, an HMG-CoA reductase inhibitor, attenuates C-Jun N-terminal kinase activation in experimental subarachnoid hemorrhage-induced apoptosis

BACKGROUND

Accumulating results have disclosed that early brain injury (EBI) may play a major role in the determination of the outcome of aneurysmal subarachnoid hemorrhage (SAH) patients. This study is of interest to examine the efficacy of pitavastatin, a 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase) inhibitor, on SAH-induced apoptosis.

METHODS

A rodent double SAH model was employed. Pitavastatin was administered orally. CSF IL-1β, IL-6, IL-8 and TNF-α were measured (rt-PCR). Basilar arteries were harvested for C-Jun N-terminal kinase p46/p55 (cJNK (p46/p55)), matrix metallopeptidase-9 (MMP-9) (Western blot), caspase and Bcl-2 (rt-PCR) evaluation.

RESULTS

Pitavastatin reduced the bioexpression of cJNK p55 compared with the SAH groups. Cleaved caspase-9a was significantly reduced in the pitavastatin-preconditioned group compared with the SAH group (p > 0.05). IL-1β and TNF-α levels were reduced in the pitavastatin-preconditioned group. Pretreatment with pitavastatin significantly reduced activated MMP-9, capsase-9a and B-cell lymphoma 2(Bcl) mRNA.

CONCLUSION

Preconditioning with pitavastatin exerts its neuroprotective effect through the dual action of inhibiting cJNK(p46/p55) activation and reducing cleaved caspase-9a expression. Besides, the bioinhibition of MMP-9 may partially contribute to the neuroprotective effect. This study lends credence to the theory that statins, especially in the preconditioning status, may attenuate SAH-induced neuron apoptosis.

Immune cells subpopulations in cerebrospinal fluid and peripheral blood of patients with Aneurysmal Subarachnoid Hemorrhage

Background

There is growing evidence supporting the role of inflammation in aneurysmal subarachnoid hemorrhage (aSAH) pathophysiology and it is of great interest to elucidate which immune mechanisms are involved.

Methods

12 aSAH patients and 28 healthy controls were enrolled prospectively. We assessed leukocytes subpopulations and their activation status by flow cytometry in cerebrospinal fluid (CSF) and peripheral blood (PB) of SAH patients at the same time and in PB of controls.

Results

Monocytes and neutrophils were activated in CSF of aSAH patients. The percentage of CD14⁺⁺CD16⁺ monocytes were higher in CSF than in PB of aSAH patients, and were also increased in PB of aSAH patients compared with controls. An enhanced expression of CD69 was shown in CSF neutrophils compared with PB in aSAH patients. PB of aSAH patients showed lower percentage of total lymphocytes compared with controls PB. Additionally, lymphocytes were activated in CSF and PB of aSAH patients. CD4⁺ and CD8⁺ T cells had a decreased expression on CD3 and higher levels of CD69 in CSF compared with PB in aSAH patients. Moreover, PB CD4⁺ and CD8⁺ T cells of aSAH patients were activated compared with controls. Additionally, CD28 expression was decreased on CSF T lymphocytes.

Conclusions

Our data suggest an important recruitment of leukocytes to the site of injury in aSAH as well as an increased activation at this level. Overall, these results indicate that aSAH probably stimulates both the innate and adaptive immune responses.

Valproic acid attenuates intercellular adhesion molecule-1 and E-selectin through a chemokine ligand 5 dependent mechanism and subarachnoid hemorrhage induced vasospasm in a rat model

BACKGROUND

Up-regulation of regulated upon activation, normal T-cell expressed and secreted (RANTES/CCL5) and adhesion molecules is observed in the serum of animals following experimental subarachnoid hemorrhage (SAH). The present study was to examine the effect of valproic acid (VPA) on RANTES and alternation of adhesion molecules in this model.

METHODS

A rodent SAH model was employed. Animals were randomly assigned into six groups. Basilar artery (BA) was harvested for intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin evaluation (western blotting) and RANTES (rt-PCR). 1 ng CCL5 recombinant protein intrathecal injection was performed in the VPA + SAH groups. (N = 5).

RESULTS

Convoluted internal elastic lamina, distorted endothelial wall, and smooth muscle micro-necrosis was prominently observed in the SAH groups, which is absent in the VPA treatment and the healthy controls. Treatment with VPA dose-dependently reduced the ICAM-1, E-selectin and RANTES level, compared with the SAH group (p <0.01). The administration of CCL5 significantly increased CD45(+) glia and ICAM-1 level in the VPA treatment groups.

CONCLUSION

VPA exerts its anti-vasospastic effect through the dual effect of inhibiting RANTES expression and reduced adhesion molecules. Besides, VPA also decreased CD45(+) cells transmigrated to the vascular wall. The administration of CCL5 significantly reversed the inhibitory effect of this compound on CD45(+) monocytes, E-selectin, and ICAM-1 level. This study also lends credence to support this compound could attenuate SAH induced adhesion molecules and neuro-inflammation in a CCL5 dependent mechanism.

Purpurogallin, a natural phenol, attenuates high-mobility group box 1 in subarachnoid hemorrhage induced vasospasm in a rat model

High-mobility group box 1 (HMGB1) was shown to be an important extracellular mediator involved in vascular inflammation of animals following subarachnoid hemorrhage (SAH). This study is of interest to examine the efficacy of purpurogallin, a natural phenol, on the alternation of cytokines and HMGB1 in a SAH model. A rodent double hemorrhage SAH model was employed. Basilar arteries (BAs) were harvested to examine HMGB1 mRNA and protein expression (Western blot). CSF samples were to examine IL-1β, IL-6, IL-8, and TNF-α (rt-PCR). Deformed endothelial wall, tortuous elastic lamina, and necrotic smooth muscle were observed in the vessels of SAH groups but were absent in the purpurogallin group. IL-1β, IL-6, and TNF-α in the SAH only and SAH plus vehicle groups were significantly elevated (P < 0.01). Purpurgallin dose-dependently reduced HMGB1 protein expression. Likewise, high dose purpurogallin reduced TNF-α and HMGB1 mRNA levels. In conclusion, purpurogallin exerts its neuroinflammation effect through the dual effect of inhibiting IL-6 and TNF-α mRNA expression and reducing HMGB1 protein and mRNA expression. This study supports purpurogallin could attenuate both proinflammatory cytokines and late-onset inflammasome in SAH induced vasospasm.

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.

The rodent endovascular puncture model of subarachnoid hemorrhage: mechanisms of brain damage and therapeutic strategies

Subarachnoid hemorrhage (SAH) represents a considerable health problem. To date, limited therapeutic options are available. In order to develop effective therapeutic strategies for SAH, the mechanisms involved in SAH brain damage should be fully explored. Here we review the mechanisms of SAH brain damage induced by the experimental endovascular puncture model. We have included a description of similarities and distinctions between experimental SAH in animals and human SAH pathology. Moreover, several novel treatment options to diminish SAH brain damage are discussed.SAH is accompanied by cerebral inflammation as demonstrated by an influx of inflammatory cells into the cerebral parenchyma, upregulation of inflammatory transcriptional pathways and increased expression of cytokines and chemokines. Additionally, various cell death pathways including cerebral apoptosis, necrosis, necroptosis and autophagy are involved in neuronal damage caused by SAH.Treatment strategies aiming at inhibition of inflammatory or cell death pathways demonstrate the importance of these mechanisms for survival after experimental SAH. Moreover, neuroregenerative therapies using stem cells are discussed as a possible strategy to repair the brain after SAH since this therapy may extend the window of treatment considerably. We propose the endovascular puncture model as a suitable animal model which resembles the human pathology of SAH and which could be applied to investigate novel therapeutic therapies to combat this debilitating insult.

Cerebral vasospasm after aneurysmal subarachnoid hemorrhage and traumatic brain injury

OPINION STATEMENT

Cerebral vasospasm (cVSP) consists of the vasoconstriction of large and small intracranial vessels which can lead to cerebral hypoperfusion, and in extreme cases, delayed ischemic deficits with stroke. While most commonly observed after aneurysmal subarachnoid hemorrhage (aSAH), cVSP can also occur after traumatic brain injury (TBI) as we have described in detail in this review. For the past decades, the research attention has focused on cVSP because of its association with delayed cerebral ischemia, which is the largest contributor of morbidity and mortality after aSAH. New discoveries in the cVSP pathophysiology involving multifactorial complex cascades and pathways pose new targets for therapeutic interventions in the prevention and treatment of cVSP. The goal of this review is to demonstrate the commonalities and differences in epidemiology and pathophysiology of both aSAH and TBI-associated cVSP, and highlight the more recently discovered pathways of cVSP. Finally, the latest cVSP surveillance methods and treatment options are illustrated.

Inflammation, cerebral vasospasm, and evolving theories of delayed cerebral ischemia

Cerebral vasospasm (CVS) is a potentially lethal complication of aneurysmal subarachnoid hemorrhage (aSAH). Recently, the symptomatic presentation of CVS has been termed delayed cerebral ischemia (DCI), occurring as early as 3-4 days after the sentinel bleed. For the past 5-6 decades, scientific research has promulgated the theory that cerebral vasospasm plays a primary role in the pathology of DCI and subsequently delayed ischemic neurological decline (DIND). Approximately 70% of patients develop CVS after aSAH with 50% long-term morbidity rates. The exact etiology of CVS is unknown; however, a well-described theory involves an antecedent inflammatory cascade with alterations of intracellular calcium dynamics and nitric oxide fluxes, though the intricacies of this inflammatory theory are currently unknown. Consequently, there have been few advances in the clinical treatment of this patient cohort, and morbidity remains high. Identification of intermediaries in the inflammatory cascade can provide insight into newer clinical interventions in the prevention and management of cerebral vasospasm and will hopefully prevent neurological decline. In this review, we discuss current theories implicating the inflammatory cascade in the development of CVS and potential treatment targets.

Anti-inflammation of spirocyclopiperazinium salt compound LXM-10 targeting α7 nAChR and M4 mAChR and inhibiting JAK2/STAT3 pathway in rats

The present study aims to investigate the therapeutic effects of LXM-10 by intragastric administration in both acute and chronic inflammatory models, and to explore the underlying molecular mechanisms. The results showed that LXM-10 produced significant anti-inflammatory effects on carrageenan induced paw edema and complete Freund's adjuvant (CFA) induced arthritis, in which LXM-10 inhibited paw swelling in a dose- and time-dependent manner. ELISA analysis showed the production of pro-inflammatory cytokines including TNF-α and IL-6 was decreased by LXM-10. Western blot analysis showed that LXM-10 significantly reduced phosphorylation of Janus kinase 2 (JAK2) and further blunted phosphorylation of signal transducer and activator of transcription-3 (STAT3). The effects that LXM-10 had shown were attenuated by methyllycaconitine citrate (an α7 nicotinic acetylcholine receptor antagonist) or tropicamide (an M4 muscarinic acetylcholine receptor antagonist) in vivo. In conclusion, the studies showed that intragastric administration of LXM-10 exerted significant anti-inflammation effects in acute and chronic models, which may be attribute to the activation of α7 nicotinic acetylcholine receptor and M4 muscarinic acetylcholine receptor, thereby inhibiting the JAK2/STAT3 signal pathway, and ultimately reducing the production of pro-inflammatory cytokines of TNF-α and IL-6.

Cerebral vasospasm pharmacological treatment: an update

Aneurysmal subarachnoid hemorrhage- (aSAH-) associated vasospasm constitutes a clinicopathological entity, in which reversible vasculopathy, impaired autoregulatory function, and hypovolemia take place, and lead to the reduction of cerebral perfusion and finally ischemia. Cerebral vasospasm begins most often on the third day after the ictal event and reaches the maximum on the 5th-7th postictal days. Several therapeutic modalities have been employed for preventing or reversing cerebral vasospasm. Triple "H" therapy, balloon and chemical angioplasty with superselective intra-arterial injection of vasodilators, administration of substances like magnesium sulfate, statins, fasudil hydrochloride, erythropoietin, endothelin-1 antagonists, nitric oxide progenitors, and sildenafil, are some of the therapeutic protocols, which are currently employed for managing patients with aSAH. Intense pathophysiological mechanism research has led to the identification of various mediators of cerebral vasospasm, such as endothelium-derived, vascular smooth muscle-derived, proinflammatory mediators, cytokines and adhesion molecules, stress-induced gene activation, and platelet-derived growth factors. Oral, intravenous, or intra-arterial administration of antagonists of these mediators has been suggested for treating patients suffering a-SAH vasospam. In our current study, we attempt to summate all the available pharmacological treatment modalities for managing vasospasm.

Influence of Fever and hospital-acquired infection on the incidence of delayed neurological deficit and poor outcome after aneurysmal subarachnoid hemorrhage

Although fever and infection have been implicated in the causation of delayed neurological deficits (DND) and poor outcome after aneurysmal subarachnoid hemorrhage (SAH), the relationship between these two often related events has not been extensively studied. We reviewed these events through of our retrospective database of patients with SAH. Multivariate logistic regression was used to determine independent predictors of DND and poor outcome. A total of 186 patients were analyzed. DND was noted in 76 patients (45%). Fever was recorded in 102 patients (55%); infection was noted in 87 patients (47%). A patient with one infection was more likely to experience DND compared to a patient with no infections (adjusted OR 3.73, 95% CI 1.62, 8.59). For those with more than two infections the likelihood of DND was even greater (adjusted OR 4.24, 95% CI 1.55, 11.56). Patients with 1-2 days of fever were less likely to have a favorable outcome when compared to their counterparts with no fever (adjusted OR 0.19, 95% CI 0.06, 0.62). This trend worsened as the number of days febrile increased. These data suggest that the presence of infection is associated with DND, but that fever may have a stronger independent association with overall outcome.

Alpha7 nicotinic acetylcholine receptor is a target in pharmacology and toxicology

Alpha7 nicotinic acetylcholine receptor (α7 nAChR) is an important part of the cholinergic nerve system in the brain. Moreover, it is associated with a cholinergic anti-inflammatory pathway in the termination of the parasympathetic nervous system. Antagonists of α7 nAChR are a wide group represented by conotoxin and bungarotoxin. Even Alzheimer's disease drug memantine acting as an antagonist in its side pathway belongs in this group. Agonists of α7 nAChR are suitable for treatment of multiple cognitive dysfunctions such as Alzheimer's disease or schizophrenia. Inflammation or even sepsis can be ameliorated by the agonistic acting compounds. Preparations RG3487, SEN34625/WYE-103914, SEN12333, ABT-107, Clozapine, GTS-21, CNI-1493, and AR-R17779 are representative examples of the novel compounds with affinity toward the α7 nAChR. Pharmacological, toxicological, and medicinal significance of α7 nAChR are discussed throughout this paper.

The role of intravenous immunoglobulin in the treatment of cerebral vasospasm induced by subarachnoid haemorrhage: an experimental study

OBJECTIVES

The aim of this study was to determine whether intravenous immunoglobulin (IVIG) prevents cerebral vasospasm in rabbits with induced subarachnoid haemorrhage (SAH). The effect of IVIG on apoptosis in the endothelial cells of the basilar artery was also evaluated.

METHODS

Eighteen New Zealand white rabbits were allocated randomly into three groups. SAH was induced by injecting autologous blood into the cisterna magna. Group 1, the control group, was subjected to sham surgery (no induction of SAH). Group 2 had SAH alone and Group 3 had SAH plus IVIG. Three days after treatment, the animals were sacrificed. The basilar artery tissues were analysed histologically and the malondialdehyde levels in the brain stem tissues were evaluated biochemically.

RESULTS

Differences in the histopathological luminal areas and full wall thicknesses in the SAH plus IVIG group and the SAH group were statically insignificant (p > 0.005). The malondialdehyde level was also found to be lower in the IVIG group than in the SAH group, although this difference was not significant (p > 0.005).

CONCLUSION

Although the IVIG treatment was revealed to have no vasodilator effect on the SAH-induced spastic basilar artery, it was shown to have a beneficial effect on the apoptosis of endothelial cells, probably via anti-inflammatory mechanisms.

Advances in experimental subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) remains to be a devastating disease with high mortality and morbidity. Two major areas are becoming the focus of the research interest of SAH: these are cerebral vasospasm (CVS) and early brain injury (EBI). This mini review will provide a broad summary of the major advances in experimental SAH during the last 3 years. Treatments interfering with nitric oxide (NO)- or endothelin-pathways continue to show antispasmotic effects in experimental SAH. HIF 1 may play both a detrimental and beneficial role in the setting of SAH, depending on its activation stage. Inflammation and oxidative stress contribute to the pathophysiology of both CVS and EBI. Apoptosis, a major component of EBI after SAH, also underlie the etiology of CVS. Since we recognize now that CVS and EBI are the two major contributors to the significant mortality and morbidity associated with SAH, ongoing research will continue to elucidate the underlying pathophysiological pathways and treatment strategies targeting both CVS and EBI may be more successful and improve outcome of patients with SAH.

Inflammation and cerebral vasospasm after subarachnoid hemorrhage

Morbidity and mortality of patients with aneurysmal subarachnoid hemorrhage (aSAH) is significantly related to the development of chronic cerebral vasospasm. Despite extensive clinical and experimental research, the pathophysiology of the events that result in delayed arterial spasm is not fully understood. A review of the published literature on cerebral vasospasm that included but was not limited to all PubMed citations from 1951 to the present was performed. The findings suggest that leukocyte-endothelial cell interactions play a significant role in the pathophysiology of cerebral vasospasm and explain the clinical variability and time course of the disease. Experimental therapeutic targeting of the inflammatory response when timed correctly can prevent vasospasm, and supplementation of endothelial relaxation by nitric oxide-related therapies and other approaches could result in reversal of the arterial narrowing and improved outcomes in patients with aSAH.

Role of inflammation (leukocyte-endothelial cell interactions) in vasospasm after subarachnoid hemorrhage

BACKGROUND

Delayed vasospasm is the leading cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). This phenomenon was first described more than 50 years ago, but only recently has the role of inflammation in this condition become better understood.

METHODS

The literature was reviewed for studies on delayed vasospasm and inflammation.

RESULTS

There is increasing evidence that inflammation and, more specifically, leukocyte-endothelial cell interactions play a critical role in the pathogenesis of vasospasm after aSAH, as well as in other conditions including meningitis and traumatic brain injury. Although earlier clinical observations and indirect experimental evidence suggested an association between inflammation and chronic vasospasm, recently direct molecular evidence demonstrates the central role of leukocyte-endothelial cell interactions in the development of chronic vasospasm. This evidence shows in both clinical and experimental studies that cell adhesion molecules (CAMs) are up-regulated in the perivasospasm period. Moreover, the use of monoclonal antibodies against these CAMs, as well as drugs that decrease the expression of CAMs, decreases vasospasm in experimental studies. It also appears that certain individuals are genetically predisposed to a severe inflammatory response after aSAH based on their haptoglobin genotype, which in turn predisposes them to develop clinically symptomatic vasospasm.

CONCLUSION

Based on this evidence, leukocyte-endothelial cell interactions appear to be the root cause of chronic vasospasm. This hypothesis predicts many surprising features of vasospasm and explains apparently unrelated phenomena observed in aSAH patients. Therapies aimed at preventing inflammation may prevent and/or reverse arterial narrowing in patients with aSAH and result in improved outcomes.

Prognostic value of histopathological findings in aneurysmal subarachnoid hemorrhage

OBJECT

Aneurysmal subarachnoid hemorrhage (SAH) carries a severe prognosis, which is often related to the development of cerebral vasospasm. Even though several clinical and radiological predictors of vasospasm and functional outcome have been established, the prognostic value of histopathological findings remains unclear.

METHODS

Histopathological findings in resected distal aneurysm walls were examined, as were the clinical and radiological factors in a series of 91 patients who had been neurosurgically treated for aneurysmal SAH. The impact of the histological, clinical, and radiological factors on the occurrence of vasospasm and functional outcome at discharge was analyzed.

RESULTS

Histopathological findings frequently included lymphocytic infiltrates (60%), fibrosis (60%), and necrosis (50%) of the resected aneurysm wall. On univariate analysis, clinical (Hunt and Hess grade) and radiological (aneurysm size) factors as well as histopathological features-namely, lymphocytic infiltrates and necrosis of the aneurysm wall-were significantly associated with the occurrence of vasospasm. On multivariate analysis, lymphocytic infiltrates (OR 6.35, 95% CI 2.32-17.36, p = 0.0001) and aneurysm size (OR 1.22, 95% CI 1.05-1.42, p = 0.009) remained the only factors predicting the development of vasospasm. A poor functional outcome at discharge was significantly associated with vasospasm, other clinical factors (Hunt and Hess grade, alcohol consumption, hyperglycemia, and elevated white blood cell count [WBC] at admission), and radiological factors (Fisher grade and aneurysm size), as well as with histopathological features (lymphocytic infiltrates [p = 0.0001] and necrosis of the aneurysm wall [p = 0.0015]). On multivariate analysis taking into account all clinical, radiological, and histological factors; vasospasm (OR 9.82, 95% CI 1.83-52.82, p = 0.008), Hunt and Hess grade (OR 5.61, 95% CI 2.29-13.74, p = 0.0001), patient age (OR 1.09, 95% CI 1.02-1.16, p = 0.0013), elevated WBC (OR 1.29, 95% CI 1.01-1.64, p = 0.04), and Fisher grade (OR 4.35, 95% CI 1.25-15.07, p = 0.015) best predicted functional outcome at discharge.

CONCLUSIONS

The demonstration of lymphocytic infiltrates in the resected aneurysm wall is of independent prognostic value for the development of vasospasm in patients with neurosurgically treated aneurysmal SAH. Thus, histopathology might complement other clinical and radiological factors in the identification of patients at risk.

New insights into the causes and therapy of cerebral vasospasm following subarachnoid hemorrhage

Cerebral vasospasm lingers as the leading preventable cause of death and disability in patients who experience aneurysmal subarachnoid hemorrhage. Despite the potentially devastating consequences of cerebral vasospasm, the mechanisms behind it are incompletely understood. Nitric oxide, endothelin-1, bilirubin oxidation products and inflammation appear to figure prominently in its pathogenesis. Therapies directed at many of these mechanisms are currently under investigation and hold significant promise for an ultimate solution to this substantial problem.