Prevention of cerebral vasospasm by a humanized anti-CD11/CD18 monoclonal antibody administered after experimental subarachnoid hemorrhage in nonhuman primates

Dynamic development of microglia and macrophages after spinal cord injury

JOURNAL/nrgr/04.03/01300535-202512000-00029/figure1/v/2025-01-31T122243Z/r/image-tiff Secondary injury following spinal cord injury is primarily characterized by a complex inflammatory response, with resident microglia and infiltrating macrophages playing pivotal roles. While previous studies have grouped these two cell types together based on similarities in structure and function, an increasing number of studies have demonstrated that microglia and macrophages exhibit differences in structure and function and have different effects on disease processes. In this study, we used single-cell RNA sequencing and spatial transcriptomics to identify the distinct evolutionary paths of microglia and macrophages following spinal cord injury. Our results showed that microglia were activated to a pro-inflammatory phenotype immediately after spinal cord injury, gradually transforming to an anti-inflammatory steady state phenotype as the disease progressed. Regarding macrophages, our findings highlighted abundant communication with other cells, including fibroblasts and neurons. Both pro-inflammatory and neuroprotective effects of macrophages were also identified; the pro-inflammatory effect may be related to integrin β2 ( Itgb2 ) and the neuroprotective effect may be related to the oncostatin M pathway. These findings were validated by in vivo experiments. This research underscores differences in the cellular dynamics of microglia and macrophages following spinal cord injury, and may offer new perspectives on inflammatory mechanisms and potential therapeutic targets.

Role of Neutrophils as Therapeutic Targets in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a major health problem. It is one of the most common types of stroke and results in mortality in approximately half of patients. More than half of the fatalities occur in the first 2 days. In addition to the mass effect after ICH hemorrhage, complex pathophysiological mechanisms such as intracranial vessel vasospasm, microthrombosis, and inflammatory immune reaction also increase brain damage. Both resident (including microglia and astrocytes) and circulating immune cells (including neutrophils, macrophages, and lymphocytes) involved in the inflammatory process. The inflammatory response is especially harmful in the acute phase due to harmful substances secreted by infiltrating immune cells. The inflammatory response also has beneficial effects, especially in the later stages. Their role in pathophysiology makes immune cells important therapeutic targets. General immunosuppressive approaches and depleting cell groups such as neutrophils or keeping them away from the lesion site may not be sufficient to prevent poor outcomes after ICH. This is most likely because they suppress anti-inflammatory activities and pro-inflammatory effects. Instead, directing immune cells to the beneficial subpopulation seems like a more rational solution. The pro-inflammatory N1 subpopulation of neutrophils damages the tissue surrounding ICH. In contrast, the N2 subpopulation is associated with anti-inflammatory reactions and tissue repair. Studies show that when neutrophils are polarized toward the N2 subpopulation, clinical outcomes improve and the volume of the infarct decreases. However, more research is still needed. This study aims to evaluate the role of neutrophils as immunotherapeutic targets in ICH in light of current knowledge.

Changes in Adhesion and the Expression of Adhesion Molecules in PBMCs after Aneurysmal Subarachnoid Hemorrhage: Relation to Cerebral Vasospasm

Aneurysmal subarachnoid hemorrhage (aSAH) is a neurovascular disease produced by extravasation of blood to the subarachnoid space after rupture of the cerebral vessels. After bleeding, the immune response is activated. The role of peripheral blood mononuclear cells (PBMCs) in this response is a current subject of research. We have analysed the changes in PBMCs of patients with aSAH and their interaction with the endothelium, focusing on their adhesion and the expression of adhesion molecules. Using an in vitro adhesion assay, we observed that the adhesion of PBMCs of patients with aSAH is increased. Flow cytometry analysis shows that monocytes increased significantly in patients, especially in those who developed vasospasm (VSP). In aSAH patients, the expression of CD162, CD49d, CD62L and CD11a in T lymphocytes and of CD62L in monocytes increased. However, the expression of CD162, CD43, and CD11a decreased in monocytes. Furthermore, monocytes from patients who developed arteriographic VSP had lower expression of CD62L. In conclusion, our results confirm that after aSAH, monocyte count and adhesion of PBMCs increase, especially in patients with VSP, and that the expression of several adhesion molecules is altered. These observations can help predict VSP and to improve the treatment of this pathology.

Clinical Potential of Immunotherapies in Subarachnoid Hemorrhage Treatment: Mechanistic Dissection of Innate and Adaptive Immune Responses

Subarachnoid hemorrhage (SAH), classified as a medical emergency, is a devastating and severe subtype of stroke. SAH induces an immune response, which further triggers brain injury; however, the underlying mechanisms need to be further elucidated. The current research is predominantly focused on the production of specific subtypes of immune cells, especially innate immune cells, post-SAH onset. Increasing evidence suggests the critical role of immune responses in SAH pathophysiology; however, studies on the role and clinical significance of adaptive immunity post-SAH are limited. In this present study, we briefly review the mechanistic dissection of innate and adaptive immune responses post-SAH. Additionally, we summarized the experimental studies and clinical trials of immunotherapies for SAH treatment, which may form the basis for the development of improved therapeutic approaches for the clinical management of SAH in the future.

Delayed Cerebral Ischemia After Subarachnoid Hemorrhage: Is There a Relevant Experimental Model? A Systematic Review of Preclinical Literature

Delayed cerebral ischemia (DCI) is one of the main prognosis factors for disability after aneurysmal subarachnoid hemorrhage (SAH). The lack of a consensual definition for DCI had limited investigation and care in human until 2010, when a multidisciplinary research expert group proposed to define DCI as the occurrence of cerebral infarction (identified on imaging or histology) associated with clinical deterioration. We performed a systematic review to assess whether preclinical models of SAH meet this definition, focusing on the combination of noninvasive imaging and neurological deficits. To this aim, we searched in PUBMED database and included all rodent SAH models that considered cerebral ischemia and/or neurological outcome and/or vasospasm. Seventy-eight publications were included. Eight different methods were performed to induce SAH, with blood injection in the cisterna magna being the most widely used (n = 39, 50%). Vasospasm was the most investigated SAH-related complication (n = 52, 67%) compared to cerebral ischemia (n = 30, 38%), which was never investigated with imaging. Neurological deficits were also explored (n = 19, 24%). This systematic review shows that no preclinical SAH model meets the 2010 clinical definition of DCI, highlighting the inconsistencies between preclinical and clinical standards. In order to enhance research and favor translation to humans, pertinent SAH animal models reproducing DCI are urgently needed.

Pathophysiology of Delayed Cerebral Ischemia After Subarachnoid Hemorrhage: A Review

Delayed cerebral ischemia is a major predictor of poor outcomes in patients who suffer subarachnoid hemorrhage. Treatment options are limited and often ineffective despite many years of investigation and clinical trials. Modern advances in basic science have produced a much more complex, multifactorial framework in which delayed cerebral ischemia is better understood and novel treatments can be developed. Leveraging this knowledge to improve outcomes, however, depends on a holistic understanding of the disease process. We conducted a review of the literature to analyze the current state of investigation into delayed cerebral ischemia with emphasis on the major themes that have emerged over the past decades. Specifically, we discuss microcirculatory dysfunction, glymphatic impairment, inflammation, and neuroelectric disruption as pathological factors in addition to the canonical focus on cerebral vasospasm. This review intends to give clinicians and researchers a summary of the foundations of delayed cerebral ischemia pathophysiology while also underscoring the interactions and interdependencies between pathological factors. Through this overview, we also highlight the advances in translational studies and potential future therapeutic opportunities.

Serum Alkaline Phosphatase Level is Associated with Angiographic Vasospasm, Delayed Cerebral Ischemia-Caused Clinical Deterioration, and Functional Outcome After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Alkaline phosphatase (ALP) has been implicated to be associated with poor outcome in ischemic stroke patients, yet its role in aneurysmal subarachnoid hemorrhage (aSAH) patients is unknown. The current study aimed to investigate the on-admission and short-term variation trend of ALP levels in aSAH patients as well as its associations with vasospasm, delayed cerebral ischemia (DCI), and outcome after aSAH.

METHODS

Between January 2014 and May 2018, all consecutive aSAH patients were prospectively enrolled. Blood samples from patients and 78 healthy individuals were obtained. Baseline information, clinical data, and radiologic data were collected, and serum ALP levels during hospitalization were measured. Patients were followed up for 6 months.

RESULTS

One hundred and ninety-six aSAH patients were included. The serum ALP levels in aSAH patients were significantly higher compared to controls (71 vs. 61 U/L, p = 0.0002), yet did not differ significantly between patients with severe (WFNS 4-5) and mild clinical condition (72 vs. 63 U/L, p = 0.3362). However, ALP was significantly higher in patients with severe radiologic status (modified Fisher 3-4) compared to those with mild radiologic status (77 vs. 61.5 U/L, p = 0.0005). A significant correlation emerged between modified Fisher score and ALP level (r = 0.246, p = 0.001). Multivariable analysis found that higher ALP level was associated with angiographic vasospasm (OR 1.019, 95% CI 1.002-1.036, p = 0.026) and DCI-caused clinical deterioration (OR 1.019, 95% CI 1.001-1.037, p = 0.037), while higher WFNS score, modified Fisher score, and ALP level were independently associated with unfavorable outcome (serum ALP level, OR 1.083, 95% CI 1.041-1.127, p < 0.001). Trend analysis of ALP level based on 103 patients' data revealed a significant decrease in ALP level on post-admission day 7-9 (median; on-admission day vs. post-admission day 7-9, 72 vs. 60 U/L, p = 0.0012; post-admission day 3-5 vs. day 7-9, 70 vs. 60 U/L, p = 0.0052) and subsequent increase in ALP level on post-admission day 12-14 (median, 84 U/L, p < 0.0001). Higher ALP levels were observed in patients with unfavorable outcome on on-admission day, post-admission day 3-5, and 12-14 (median; unfavorable vs. favorable; on-admission day, 86 vs. 67 U/L, p = 0.0122; post-admission day 3-5, 80 vs. 64 U/L, p = 0.0044; post-admission day 7-9, 75 vs. 53.5 U/L, p < 0.0001) but not on post-admission day 12-14.

CONCLUSIONS

Elevated serum ALP level is associated with vasospasm, DCI-caused clinical deterioration, and functional outcome after aSAH. Further studies are required to examine the potential role of serum ALP as an outcome predictor for aSAH patients.

Neuroinflammation and Microvascular Dysfunction After Experimental Subarachnoid Hemorrhage: Emerging Components of Early Brain Injury Related to Outcome

Aneurysmal subarachnoid hemorrhage has a high mortality rate and, for those who survive this devastating injury, can lead to lifelong impairment. Clinical trials have demonstrated that cerebral vasospasm of larger extraparenchymal vessels is not the sole contributor to neurological outcome. Recently, the focus of intense investigation has turned to mechanisms of early brain injury that may play a larger role in outcome, including neuroinflammation and microvascular dysfunction. Extravasated blood after aneurysm rupture results in a robust inflammatory response characterized by activation of microglia, upregulation of cellular adhesion molecules, recruitment of peripheral immune cells, as well as impaired neurovascular coupling, disruption of the blood-brain barrier, and imbalances in endogenous vasodilators and vasoconstrictors. Each of these phenomena is either directly or indirectly associated with neuronal death and brain injury. Here, we review recent studies investigating these various mechanisms in experimental models of subarachnoid hemorrhage with special emphasis on neuroinflammation and its effect on microvascular dysfunction. We discuss the various therapeutic targets that have risen from these mechanistic studies and suggest the utility of a multi-targeted approach to preventing delayed injury and improving outcome after subarachnoid hemorrhage.

Neutrophils mediate early cerebral cortical hypoperfusion in a murine model of subarachnoid haemorrhage

Cerebral hypoperfusion in the first hours after subarachnoid haemorrhage (SAH) is a major determinant of poor neurological outcome. However, the underlying pathophysiology is only partly understood. Here we induced neutropenia in C57BL/6N mice by anti-Ly6G antibody injection, induced SAH by endovascular filament perforation, and analysed cerebral cortical perfusion with laser SPECKLE contrast imaging to investigate the role of neutrophils in mediating cerebral hypoperfusion during the first 24 h post-SAH. SAH induction significantly increased the intracranial pressure (ICP), and significantly reduced the cerebral perfusion pressure (CPP). At 3 h after SAH, ICP had returned to baseline and CPP was similar between SAH and sham mice. However, in SAH mice with normal neutrophil counts cortical hypoperfusion persisted. Conversely, despite similar CPP, cortical perfusion was significantly higher at 3 h after SAH in mice with neutropenia. The levels of 8-iso-prostaglandin-F2α in the subarachnoid haematoma increased significantly at 3 h after SAH in animals with normal neutrophil counts indicating oxidative stress, which was not the case in neutropenic SAH animals. These results suggest that neutrophils are important mediators of cortical hypoperfusion and oxidative stress early after SAH. Targeting neutrophil function and neutrophil-induced oxidative stress could be a promising new approach to mitigate cerebral hypoperfusion early after SAH.

The role of inflammation and potential use of sex steroids in intracranial aneurysms and subarachnoid hemorrhage

Background

Aneurysmal subarachnoid hemorrhage (aSAH) continues to be a devastating neurological condition with a high risk of associated morbidity and mortality. Inflammation has been shown to increase the risk of complications associated with aSAH such as vasospasm and brain injury in animal models and humans. The goal of this review is to discuss the inflammatory mechanisms of aneurysm formation, rupture and vasospasm and explore the role of sex hormones in the inflammatory response to aSAH.

Methods

A literature review was performed using PubMed using the following search terms: "intracranial aneurysm," "cerebral aneurysm," "dihydroepiandrosterone sulfate" "estrogen," "hormone replacement therapy," "inflammation," "oral contraceptive," "progesterone," "sex steroids," "sex hormones" "subarachnoid hemorrhage," "testosterone." Only studies published in English language were included in the review.

Results

Studies have shown that administration of sex hormones such as progesterone and estrogen at early stages in the inflammatory cascade can lower the risk and magnitude of subsequent complications. The exact mechanism by which these hormones act on the brain, as well as their role in the inflammatory cascade is not fully understood. Moreover, conflicting results have been published on the effect of hormone replacement therapy in humans. This review will scrutinize the variations in these studies to provide a more detailed understanding of sex hormones as potential therapeutic agents for intracranial aneurysms and aSAH.

Conclusion

Inflammation may play a role in the pathogenesis of intracranial aneurysm formation and subarachnoid hemorrhage, and administration of sex hormones as anti-inflammatory agents has been associated with improved functional outcome in experimental models. Further studies are needed to determine the therapeutic role of these hormones in the intracranial aneurysms and aSAH.

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.

Inflammatory Events Following Subarachnoid Hemorrhage (SAH)

Acute SAH from a ruptured intracranial aneurysm contributes for 30% of all hemorrhagic strokes. The bleeding itself occurs in the subarachnoid space. Nevertheless, injury to the brain parenchyma occurs as a consequence of the bleeding, directly, via several well-defined mechanisms and pathways, but also indirectly, or secondarily. This secondary brain injury following SAH has a variety of causes and possible mechanisms. Amongst others, inflammatory events have been shown to occur in parallel to, contribute to, or even to initiate programmed cell death (PCD) within the central nervous system (CNS) in human and animal studies alike. Mechanisms of secondary brain injury are of utmost interest not only to scientists, but also to clinicians, as they often provide possibilities for translational approaches as well as distinct time windows for tailored treatment options. In this article, we review secondary brain injury due to inflammatory changes, that occur on cellular, as well as on molecular level in the various different compartments of the CNS: the brain vessels, the subarachnoid space, and the brain parenchyma itself and hypothesize about possible signaling mechanisms between these compartments.

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.

Heparin and Heparin-Derivatives in Post-Subarachnoid Hemorrhage Brain Injury: A Multimodal Therapy for a Multimodal Disease

Pharmacologic efforts to improve outcomes following aneurysmal subarachnoid hemorrhage (aSAH) remain disappointing, likely owing to the complex nature of post-hemorrhage brain injury. Previous work suggests that heparin, due to the multimodal nature of its actions, reduces the incidence of clinical vasospasm and delayed cerebral ischemia that accompany the disease. This narrative review examines how heparin may mitigate the non-vasospastic pathological aspects of aSAH, particularly those related to neuroinflammation. Following a brief review of early brain injury in aSAH and heparin’s general pharmacology, we discuss potential mechanistic roles of heparin therapy in treating post-aSAH inflammatory injury. These roles include reducing ischemia-reperfusion injury, preventing leukocyte extravasation, modulating phagocyte activation, countering oxidative stress, and correcting blood-brain barrier dysfunction. Following a discussion of evidence to support these mechanistic roles, we provide a brief discussion of potential complications of heparin usage in aSAH. Our review suggests that heparin’s use in aSAH is not only safe, but effectively addresses a number of pathologies initiated by aSAH.

Neuroinflammation responses after subarachnoid hemorrhage: A review

Subarachnoid hemorrhage (SAH) is an important cause of stroke mortality and morbidity, especially in the young stroke population. Recent evidences indicate that neuroinflammation plays a critical role in both early brain injury and the delayed brain deterioration after SAH, including cellular and molecular components. Cerebral vasospasm (CV) can lead to death after SAH and independently correlated with poor outcome. Neuroinflammation is evidenced to contribute to the etiology of vasospasm. Besides, systemic inflammatory response syndrome (SIRS) commonly occurs in the SAH patients, with the presence of non-infectious fever and systematic complications. In this review, we summarize the evidences that indicate the prominent role of inflammation in the pathophysiology of SAH. That may provide the potential implications on diagnostic and therapeutic strategies.

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.

Neutrophil depletion after subarachnoid hemorrhage improves memory via NMDA receptors

Cognitive deficits after aneurysmal subarachnoid hemorrhage (SAH) are common and disabling. Patients who experience delayed deterioration associated with vasospasm are likely to have cognitive deficits, particularly problems with executive function, verbal and spatial memory. Here, we report neurophysiological and pathological mechanisms underlying behavioral deficits in a murine model of SAH. On tests of spatial memory, animals with SAH performed worse than sham animals in the first week and one month after SAH suggesting a prolonged injury. Between three and six days after experimental hemorrhage, mice demonstrated loss of late long-term potentiation (L-LTP) due to dysfunction of the NMDA receptor. Suppression of innate immune cell activation prevents delayed vasospasm after murine SAH. We therefore explored the role of neutrophil-mediated innate inflammation on memory deficits after SAH. Depletion of neutrophils three days after SAH mitigates tissue inflammation, reverses cerebral vasoconstriction in the middle cerebral artery, and rescues L-LTP dysfunction at day 6. Spatial memory deficits in both the short and long-term are improved and associated with a shift of NMDA receptor subunit composition toward a memory sparing phenotype. This work supports further investigating suppression of innate immunity after SAH as a target for preventative therapies in SAH.

Cerebral Vasospasm: A Review

Cerebral vasospasm is a prolonged but reversible narrowing of cerebral arteries beginning days after subarachnoid hemorrhage. Progression to cerebral ischemia is tied mostly to vasospasm severity, and its pathogenesis lies in artery encasement by blood clot, although the complex interactions between hematoma and surrounding structures are not fully understood. The delayed onset of vasospasm provides a potential opportunity for its prevention. It is disappointing that recent randomized, controlled trials did not demonstrate that the endothelin antagonist clazosentan, the cholesterol-lowering agent simvastatin, and the vasodilator magnesium sulfate improve patient outcome. Minimizing ischemia by avoiding inadequate blood volume and pressure, administering the calcium antagonist nimodipine, and intervention with balloon angioplasty, when necessary, constitutes current best management. Over the past two decades, our ability to manage vasospasm has led to a significant decline in patient morbidity and mortality from vasospasm, yet it still remains an important determinant of outcome after aneurysm rupture.

Curcumin, encapsulated in nano-sized PLGA, down-regulates nuclear factor κB (p65) and subarachnoid hemorrhage induced early brain injury in a rat model

BACKGROUND

More and more evidence revealed early brain injury (EBI) may determine the final outcome in aneurismal subarachnoid hemorrhage (SAH) patients. This study is of interest to examine the efficacy of nano-particle curcumin (nanocurcumin), a diarylheptanoid, on a SAH-induced EBI model.

METHODS

A rodent double hemorrhage model was employed. Nanocurcumin (75/150/300μg/kg/day) was administered via osmotic mini-pump post-SAH. CSF samples were collected to examine IL-1β, IL-6, IL-8 and TNF-α (rt-PCR). Cerebral cortex was harvested for NF-κB (p50/p65) (western blot), caspases (rt-PCR) measurement.

RESULTS

Nanocurcumin significantly reduced the bio-expression of NF-κB (p65), when compared with the SAH groups. The levels of IL-1β and IL-6 were increased in animals subjected to SAH, compared with the healthy controls, but absent in the high dose nanocurcumin+SAH group. Moreover, the levels of TNF-α in the SAH groups were significantly elevated. Treatment with nanocurcumin (300μg/kg) reduced the level to the healthy control. The cleaved caspase-3 and -9a was significantly reduced in 300μg/kg nanocurcumin treatment groups (P<0.05).

CONCLUSION

Treatment with nanocurcumin exerts its neuroprotective effect through the upward regulation of NF-κB (p65) and also reduced mitochondrion related caspase-9a expression. Besides, nanocurcumin decreased CSF levels of TNF-α and IL-1β, which may contribute to the extrinsic antiapoptotic effect. This study shows promise to support curcuminin, in a nano-particle, could attenuate SAH induced EBI.

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.

A glutamate receptor antagonist, S-4-carboxyphenylglycine (S-4-CPG), inhibits vasospasm after subarachnoid hemorrhage in haptoglobin 2-2 mice [corrected]

BACKGROUND

Vasospasm contributes to delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage (SAH). Glutamate concentrations increase after SAH and correlate with vasospasm in experimental SAH. The haptoglobin (Hp) 2-2 genotype is associated with higher risk of vasospasm after SAH. We tested the efficacy of (S)-4-carboxyphenylglycine (S-4-CPG), a metabotropic glutamate receptor inhibitor, for the treatment of vasospasm after SAH in Hp 2-2 and Hp 1-1 mice.

OBJECTIVE

To evaluate the effect on vasospasm and neurobehavioral scores after SAH of systemic S-4-CPG, as well as its toxicity, and phosphorylation of vasodilator-stimulated phosphoprotein (VASP) in Hp 2-2 mice.

METHODS

Western blot was used to assess changes in VASP phosphorylation in response to glutamate with and without S-4-CPG. A pharmacokinetics study was done to evaluate S-4-CPG penetration through the blood-brain barrier in vivo. Toxicity was assessed by administering increasing S-4-CPG doses. Efficacy of S-4-CPG assessed the effect of S-4-CPG on lumen patency of the basilar artery and animal behavior after SAH in Hp 1-1 and Hp 2-2 mice. Immunohistochemistry was used to evaluate the presence of neutrophils surrounding the basilar artery after SAH.

RESULTS

Exposure of human brain microvascular endothelial cells to glutamate decreased phosphorylation of VASP, but glutamate treatment in the presence of S-4-CPG maintains phosphorylation of VASP. S-4-CPG crosses the blood-brain barrier and was not toxic to mice. S-4-CPG treatment significantly prevents vasospasm after SAH. S-4-CPG administered after SAH resulted in a trend toward improvement of animal behavior.

CONCLUSION

S-4-CPG prevents vasospasm after experimental SAH in Hp2-2 mice. S-4-CPG was not toxic and is a potential therapeutic agent for vasospasm after SAH.

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.

Sulforaphane enhances the activity of the Nrf2-ARE pathway and attenuates inflammation in OxyHb-induced rat vascular smooth muscle cells

AIM

A growing body of evidence indicates that the nuclear factor erythroid 2-related factor 2-antioxidant response element (Nrf2-ARE) pathway plays a protective role in many physiological stress processes such as inflammatory damage, oxidative stress, and the accumulation of toxic metabolites, which are all involved in the cerebral vasospasm following subarachnoid hemorrhage (SAH). We hypothesized that the Nrf2-ARE pathway might have a protective role in cerebral vasospasm following SAH.

MATERIALS AND METHODS

In our study, we investigate whether the oxyhemoglobin (OxyHb) can induce the activation of the Nrf2-ARE pathway in vascular smooth muscle cells (VSMCs), and evaluate the modulatory effects of sulforaphane (SUL) on OxyHb-induced inflammation in VSMCs.

RESULTS

As a result, both the protein level and the mRNA level of the nuclear Nrf2 were significantly increased, while the mRNA levels of two Nrf2-regulated gene products, both heme oxygenase-1 and NAD(P)H: quinone oxidoreductase-1, were also up-regulated in VSMCs induced with OxyHb. A marked increase of inflammatory cytokines such as IL-1β, IL-6 and TNF-α release was observed at 48 h after cells were treated with OxyHb. SUL enhanced the activity of the Nrf2-ARE pathway and suppressed cytokine release.

CONCLUSIONS

Our results indicate that the Nrf2-ARE pathway was activated in OxyHb-induced VSMCs. SUL suppressed cytokine release via the activation of the Nrf2-ARE pathway in OxyHb-induced VSMCs.

Inflammation in subarachnoid hemorrhage and delayed deterioration associated with vasospasm: a review

Delayed deterioration associated with vasospasm (DDAV) after subarachnoid hemorrhage (SAH), (often called vasospasm) continues to be both a difficult entity to treat and a leading cause of morbidity in patients. Until recently, attention was focused on alleviating the vascular spasm. Recent evidence shows that vascular spasm may not account for all the morbidity of DDAV. There is renewed interest in looking for other potential targets for therapy. Inflammation has become a promising area of research for new treatments. This review explores the evidence that inflammation is a driver of DDAV by asking three questions: (1) If inflammation is important in the pathogenesis of the disease, what part or parts of the inflammatory response are involved? (2) When does inflammation occur in SAH? (3) In what compartment of the skull does the inflammation occur, the cerebrospinal fluid and meninges, the cerebral arteries, or the brain itself?

Statins and anti-inflammatory therapies for subarachnoid hemorrhage

OPINION STATEMENT

Aneurysmal subarachnoid hemorrhage (SAH) induces a potent inflammatory cascade that contributes to endothelial dysfunction, imbalance of vasoactive substances (excess endothelin, depletion of nitric oxide), and arterial vasospasm. This process results in delayed cerebral ischemia, a major cause of neurologic disability in those surviving the initial hemorrhage. The only therapy shown to be effective in improving neurologic outcomes after SAH is a calcium-channel antagonist, nimodipine (although it achieved this result without reducing vasospasm). A number of novel therapies have been explored to inhibit the development of vasospasm and reduce the burden of ischemia and cerebral infarction. Statins are promising candidates, as they block multiple aspects of the inflammatory pathway that contributes to ischemic brain injury. Early clinical trials have produced conflicting results, however, and the adoption of statins in clinical practice should await the results of larger, more definitive studies. Though endothelin-receptor antagonists showed promise in significantly reducing vasospasm in preliminary trials, their failure to improve clinical outcomes in phase 3 studies has been disappointing, highlighting the complex link between vasospasm and ischemia. Future directions in the quest to improve outcomes of patients with SAH may need to approach ischemia as a multifactorial process with inflammatory, vasoactive, and ionic/metabolic components.

Purine anti-metabolite attenuates nuclear factor κB and related pro-inflammatory cytokines in experimental vasospasm

BACKGROUND

Increased nuclear factor κB (NF-κB) bioexpression, as well as TNF-α, IL-1β and IL-6 levels, were observed after aneurysmal subarachnoid hemorrhage (SAH). It is of interest to investigate the effect of 6-mercaptopurine (6-mp) on cytokines/NF-κB in this SAH model.

MATERIALS AND METHODS

A rodent double-hemorrhage SAH model was employed. Serum and cerebrospinal fluid (CSF) samples were collected to examine IL-1, IL-6 and TNF-α levels. NF-κB subunit p65 and its inhibitor of nuclear factor κB (IκB) were examined (by Western blot). TNF-α was used to induce the phosphorylation of IκB in the presence or absence of 6-mp.

RESULTS

Nuclear NF-κB subunit p65/IκB kinase in the basilar artery was over-expressed, and cytokines was notably increased in the SAH groups, compared with the controls (P < 0.01). In the 6-mp SAH group, obvious reduction was observed in NF-κB subunit p65 (nuclei) (P < 0.01). Treatment with 6-mp significantly reduced IL-1β and TNF-α levels to those of the healthy control. 6-Mercaptopurine also significantly increased the level of IκB in the TNF-α-stimulated SAH rats.

CONCLUSIONS

Through inhibiting IκB bioexpression, 6-mp decreases NF-κB-related IL-1β, IL-6, and TNF-α in the presence of SAH. The study suggests 6-mp exerts vascular anti-inflammatory properties through inhibiting IκB kinase and subsequently blocks bio-activation of NF-κB and related cytokines, which may contribute to its antivasospastic effect in animals subjected to SAH.

Systemic administration of LPS worsens delayed deterioration associated with vasospasm after subarachnoid hemorrhage through a myeloid cell-dependent mechanism

BACKGROUND

Delayed deterioration associated with vasospasm (DDAV) after aneurismal subarachnoid hemorrhage (SAH) is a major cause of morbidity. We have previously shown that myeloid cell depletion before experimental SAH in a murine model ameliorates DDAV. In this study, we address whether systemic administration of lipopolysaccharide (LPS) worsens DDAV in a myeloid cell-dependent fashion.

METHODS

We challenged mice in our experimental SAH model with LPS before hemorrhage and evaluated the degree of vasospasm on day 6 with India ink angiography; behavioral deficits by rotorod, Y-maze, and Barnes maze testing; microglial activation early after SAH by immunohistochemistry; and the brain levels of the chemokines CCL5 and KC at the time of vasospasm. Another group of animals were given the myeloid cell-depleting antibody against the neutrophil antigen Ly6G/C prior to LPS administration and SAH.

RESULTS

LPS followed by SAH significantly worsens angiographic vasospasm as well as performance on the Barnes maze but not the Y-maze or rotorod tests. There was an increased activation of microglia in animals with LPS before SAH compared to SAH alone. Depletion of myeloid cells before LPS administration inhibited the development of vasospasm, improved the performance on behavioral tests, and reduced microglial activation. The chemokines CCL5 and KC were incrementally elevated in SAH and LPS SAH, but suppressed in animals with myeloid cell depletion.

CONCLUSIONS

LPS administration before SAH worsens DDAV through a myeloid cell-dependent mechanism supporting studies in humans which show that systemic inflammation increases the likelihood of developing DDAV.

Unfractionated heparin: multitargeted therapy for delayed neurological deficits induced by subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is associated with numerous "delayed neurological deficits" (DNDs) that have been attributed to multiple pathophysiological mechanisms, including ischemia, microthrombosis, free radical damage, inflammation, and vascular remodeling. To date, effective prophylactic therapy for SAH-induced DNDs has been elusive, due perhaps to the multiplicity of mechanisms involved that render typical, single-agent therapy seemingly futile. We hypothesized that heparin, which has multiple underappreciated salutary effects, might be useful as a multitargeted prophylactic agent against SAH-induced DNDs. We performed a comprehensive review of the literature to evaluate the potential utility of heparin in targeting the multiple pathophysiological mechanisms that have been identified as contributing to SAH-induced DNDs. Our literature review revealed that unfractionated heparin can potentially antagonize essentially all of the pathophysiological mechanisms known to be activated following SAH. Heparin binds >100 proteins, including plasma proteins, proteins released from platelets, cytokines, and chemokines. Also, heparin complexes with oxyhemoglobin, blocks the activity of free radicals including reactive oxygen species, antagonizes endothelin-mediated vasoconstriction, smooth muscle depolarization, and inflammatory, growth and fibrogenic responses. Our review suggests that the use of prophylactic heparin following SAH may warrant formal study.

Monitoring of the inflammatory response after aneurysmal subarachnoid haemorrhage in the clinical setting: review of literature and report of preliminary clinical experience

BACKGROUND

Clinical and experimental studies showed a marked inflammatory response in aneurysmal subarachnoid haemorrhage (SAH), and it has been proposed to play a key role in the development of cerebral vasospasm (CVS). Inflammatory response and occurrence of CVS may represent a common pathogenic pathway allowing point of care diagnostics of CVS. Therefore, monitoring of the inflammatory response might be useful in the daily clinical setting of an ICU. The aim of the current report is to give a summary about factors contributing to the complex pathophysiology of inflammatory response in SAH and to discuss possible monitoring modalities.

METHODS

Review and analysis of the existing literature and definition of own study protocols.

RESULTS

In cerebrospinal fluid, interleukin (IL)-6 has been found to be significantly higher in patients with CVS during the peri-vasospasm period. While systemic inflammatory response syndrome, high C-reactive protein levels and leukocyte counts has been linked with the occurrence of CVS, less has been reported about cytokines levels in the jugular bulb of the internal jugular vein and in the peripheral blood. Preliminary evaluation of own data suggests, that IL-6 values in the peripheral blood and the arterio-jugular differences of IL-6 are increased with the inflammatory response after SAH.

CONCLUSION

Monitoring of the inflammatory response, in particular IL-6, might be a useful tool for the daily clinical management of patients with SAH and CVS.

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.

6-Mercaptopurine attenuates adhesive molecules in experimental vasospasm

OBJECTIVE

Adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin, are important inflammatory mediators which are elevated in the serum of patients following aneurysmal subarachnoid hemorrhage (SAH). The authors previously found that 6-mercaptopurine (6-mp) was effective in preventing and reversing arterial narrowing in a rodent SAH model. The present study was to examine whether levels of adhesion molecules were altered after treatment with 6-mp in this animal model.

MATERIALS AND METHODS

Animals were each injected with autologous blood into the cisterna magna, and intraperitoneal treatment with 6-mp (2 mg/kg) was initiated 1 h before (prevention) or later (treatment). The compound was subsequently administered at 24 and 48 h post-SAH. Blood samples were collected at 72 h post-SAH to measure ICAM-1, VCAM-1, and E-selectin levels. The basilar arteries were harvested and sliced, and their cross-sectional areas were measured. Morphologically, convolution of the internal elastic lamina, distorted endothelial wall, and myonecrosis of the smooth muscle were prominently observed in the SAH only and vehicle-treated SAH groups, but not in the 6-mp-treated SAH group or in healthy controls. No significant differences were found in the levels of VCAM-1 among all groups. However, the levels of E-selectin were increased in all animals subjected to SAH (SAH only and SAH plus vehicle groups) compared with healthy controls (no SAH), but not in the 6-mp group (SAH plus 6-mp treatment and preventive treatment with 6-mp).Likewise, the levels of ICAM-1 in the SAH only and SAH plus vehicle groups were significantly elevated (p < 0.001), and pretreatment and treatment with 6-mp reduced ICAM-1 to control levels.

CONCLUSION

These results show that ICAM-1 and E-selectin may play a role in mediating SAH-induced vasospasm and that a reduction of both adhesive molecules after SAH may partly contribute to the antispastic effect of 6-mp.

Controlled delivery of nitric oxide inhibits leukocyte migration and prevents vasospasm in haptoglobin 2-2 mice after subarachnoid hemorrhage

OBJECTIVE

Cerebral vasospasm is the leading cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH) occurs. The haptoglobin 2-2 genotype likely increases the risk for developing posthemorrhagic vasospasm, but potential treatments for vasospasm have never been tested in an animal model of this genotype. We used the nitric oxide (NO) donor diethylenetriamine (DETA)/NO incorporated into ethylene/vinyl acetate (EVAc) polymers to evaluate the efficacy of controlled NO repletion in a haptoglobin 2-2 mouse basilar artery SAH model.

METHODS

Mice were randomized to 3 groups: autologous blood injection and empty polymer implantation into the subarachnoid space (n = 16); blood injection and 30% DETA/NO-EVAc implantation (n = 20); and sham operation (n = 19). At 24 hours after surgery, activity level was assessed on a 3-point scale, and basilar arteries were processed for morphometric measurements. Leukocyte extravasation was assessed by immunohistochemistry (n = 12).

RESULTS

Treatment with controlled release of NO from DETA/NO-EVAc polymers after SAH resulted in a significant increase in basilar artery lumen patency (73.3% +/- 4.3% versus 96.5% +/- 4.3%, mean +/- standard error of the mean; P = 0.01), a significant improvement in activity after experimental SAH (2.14 +/- 0.14 versus 2.56 +/- 0.10 points; P = 0.025), and a significant decrease in extravasated leukocytes (21 +/- 4.55 versus 6.75 +/- 3.77 leukocytes per high-power field, untreated versus treated mice; P = 0.001).

CONCLUSION

Treatment with controlled release of NO prevented posthemorrhagic vasospasm in haptoglobin 2-2 mice, and mitigated neurological deficits, suggesting that DETA/NO-EVAc would be an effective therapy in patients with a genotype that confers higher risk for vasospasm after SAH. In addition to smooth muscle relaxation, inhibition of leukocyte migration may contribute to the therapeutic mechanism of NO.

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.

Simvastatin for the prevention of symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage: a single-institution prospective cohort study

OBJECT

Vasospasm is the major cause of disability and death after aneurysmal subarachnoid hemorrhage (aSAH). Although the results of 2 randomized clinical trials demonstrated that statin decreases the incidence of symptomatic cerebral vasospasm after aSAH, retrospective studies have failed to confirm this. The authors conducted a prospective observational study to determine whether a standardized regimen of simvastatin would reduce the incidence of cerebral vasospasm and improve neurological outcomes in patients with aSAH.

METHODS

Since 1991, all patients with aSAH admitted to the authors' institution have been prospectively followed up with standardized outcomes recording. Starting in September 2005, all patients admitted with aSAH were given enteral simvastatin (80 mg/day for 14 days) in addition to the standard care. The incidence of symptomatic cerebral vasospasm, length of hospitalization, in-hospital mortality rate, and discharge Glasgow Outcome Scale scores in these 170 patients were compared to data obtained in 170 consecutive patients who underwent treatment in our unit prior to the introduction of statin therapy.

RESULTS

The 5-year study period included 340 consecutively treated patients (170 who received statins and 170 who did not). Patients who received simvastatin therapy were more frequently male (29 vs 20%) and had a smaller median aneurysm diameter (6 vs 7 mm). Baseline characteristics were otherwise similar between the cohorts. There were no differences in the incidence of symptomatic vasospasm (25.3 vs 30.5%; p = 0.277), in-hospital mortality rate (18 vs 15%; p = 0.468), length of hospitalization (21 +/- 15 vs 19 +/- 12 days; p = 0.281), or poor outcome at discharge (Glasgow Outcome Scale Scores 1-2: 21.7 vs 18.2%; p = 0.416) between the simvastatin and nonstatin cohorts. There were no statin-related complications.

CONCLUSIONS

The uniform introduction of simvastatin did not reduce the incidence of symptomatic cerebral vasospasm, death, or poor outcome in patients with aSAH. Simvastatin was well tolerated, but its benefit may be less than has been previously reported.

Relationship between sympathetic nervous activity and inflammatory response after subarachnoid hemorrhage in a perforating canine model

The objective of the present study was to evaluate the correlation between sympathetic nerve activation and inflammatory response in the acute stage of subarachnoid hemorrhage (SAH) in a canine perforating model. SAH was induced by perforation of the basilar artery with the use of a microcatheter via the femoral artery in 20 mongrel dogs. Hemodynamic parameters and intracranial pressure were recorded, and blood sample for C3a, C5b-9, IL-6, IL-8 and noradrenaline kinetic determination were measured at 0, 5, 15, 30, 60, 120, and 180 min after SAH. Noradrenaline (pg/mL) increased abruptly from 104+/-59 to 2010+/-918 at 5 min after SAH. C3a and C5b-9 reached peak values at 15 min and IL-6 and IL-8 reached peak values at 30 min after SAH, respectively. The peak values of C3a and C5b-9 correlated positively with the peak value of noradrenaline (r=0.743 and r=0.753, respectively). The peak values of IL-6 and IL-8 also correlated positively with the peak values of noradrenaline (r=0.603 and r=0.681, respectively).These results suggest that a pronounced activation of the sympathetic nervous system and the inflammatory response occurs in acute stage of SAH. Significant association between the rate of spillover of norepinephrine to plasma and the plasma levels of inflammatory markers indicates that the two processes, sympathetic activation and immune response are quantitatively linked in early stage after SAH. The exact mechanisms underlying this phenomenon deserved further investigations.

A review of medical treatments of cerebral vasospasm

We review the literature on the established perioperative therapies for cerebral vasospasm (CV) following aneurysmal subarachnoid hemorrhage (aSAH). Despite aSAH treatment advances, CV continues to be a significant source of post-SAH morbidity and mortality. In fact, CV has been correlated with a 7.5- to three-fold increase in mortality in the first 2 weeks after SAH. As new treatment modalities show promise in animal models and early clinical trials, greater efforts are needed to test these new approaches. Few evidence-based indications for the treatment of vasospasm currently exist. Large-scale randomized clinical trials are needed to determine whether therapies such as magnesium, statins, nitric oxide modulators, endothelin antagonists and others will become standard of care in the prevention and/or treatment of CV.

The burden of the systemic inflammatory response predicts vasospasm and outcome after subarachnoid hemorrhage

INTRODUCTION

Subarachnoid hemorrhage (SAH) can trigger immune activation sufficient to induce the systemic inflammatory response syndrome (SIRS). This may promote both extra-cerebral organ dysfunction and delayed cerebral ischemia, contributing to worse outcome. We ascertained the frequency and predictors of SIRS after spontaneous SAH, and determined whether degree of early systemic inflammation predicted the occurrence of vasospasm and clinical outcome.

METHODS

Retrospective analysis of prospectively collected data on 276 consecutive patients admitted to a neurosciences intensive care unit with acute, non-traumatic SAH between 2002 and 2005. A daily SIRS score was derived by summing the number of variables meeting standard criteria (HR >90, RR >20, Temperature >38 degrees C, or <36 degrees C, WBC count <4,000 or >12,000). SIRS was considered present if two or more criteria were met, while SIRS burden over the first four days was calculated by averaging daily scores. Regression modeling was used to determine the relationship among SIRS burden (after controlling for confounders including infection, surgery, and corticosteroid use), symptomatic vasospasm, and outcome, determined by hospital disposition.

RESULTS

SIRS was present in over half the patients on admission and developed in 85% within the first four days. Factors associated with SIRS included poor clinical grade, thick cisternal blood, larger aneurysm size, higher admission blood pressure, and surgery for aneurysm clipping. Higher SIRS burden was independently associated with death or discharge to nursing home (OR 2.20/point, 95% CI 1.27-3.81). All of those developing clinical vasospasm had evidence of SIRS, with greater SIRS burden predicting increased risk for delayed ischemic neurological deficits (OR 1.77/point, 95% CI 1.12-2.80).

CONCLUSIONS

Systemic inflammatory activation is common after SAH even in the absence of infection; it is more frequent in those with more severe hemorrhage and in those who undergo surgical clipping. Higher burden of SIRS in the initial four days independently predicts symptomatic vasospasm and is associated with worse outcome.

CONTROVERSIES IN THE ENDOVASCULAR MANAGEMENT OF CEREBRAL VASOSPASM AFTER INTRACRANIAL ANEURYSM RUPTURE AND FUTURE DIRECTIONS FOR THERAPEUTIC APPROACHES

CEREBRAL VASOSPASM IS one of the leading causes of morbidity and mortality after aneurysmal subarachnoid hemorrhage. Despite maximal medical therapy, however, up to 15% of patients surviving the ictus of subarachnoid hemorrhage experience stroke or death from vasospasm. For those cases of vasospasm that are refractory to medical treatment, endovascular techniques are frequently used, including balloon angioplasty with or without intra-arterial infusion of vasodilators, combined endovascular modalities, and aortic balloon devices. In this article, we review each of these therapies and their expanding role in the management of this condition. Moving forward, rigorous prospective outcome assessments after endovascular treatment of cerebral vasospasm are necessary to clearly delineate the efficacy and indications for these techniques.

Anti-inflammatory effect of meloxicam on experimental vasospasm in the rat femoral artery

Cerebral vasospasm influences morbidity and mortality following subarachnoid haemorrhage (SAH). Inflammation is believed to play a role in post-haemorrhagic vasospasm. Meloxicam is a non-steroidal anti-inflammatory drug. We investigated the effect of meloxicam on a rat femoral artery vasospasm model using the radial wall thickness and cross-sectional lumen area as parameters under light, scanning and transmission electron microscopy examination. Rats were randomly separated into SAH, SAH+ meloxicam and control groups. Rats in the SAH+ meloxicam group were given meloxicam at 2 mg/kg daily for 7 days. Femoral arteries were examined by light microscopy and scanning and transmission electron microscopy, and for morphometric analysis. A statistically significant difference (p<0.001) was detected between the SAH and SAH+ meloxicam groups. Meloxicam treatment reduced ultrastructural and morphometric vasospastic changes. These findings support the hypothesis that inflammation may play a role in the pathophysiologyical pathways of post-haemorrhagic cerebral vasospasm.

Transcriptional regulation of inflammatory and extracellular matrix–regulating genes in cerebral arteries following experimental subarachnoid hemorrhage in rats

Object

Subarachnoid hemorrhage (SAH) results in the expression of inflammatory and extracellular matrix (ECM)–related genes and various G protein–coupled receptors. In the present study, the authors evaluated the time course and sequence of the transduction pathways, p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase–1 and 2 (ERK1/2), and associated transcription factor activation as well as gene regulation and associated protein levels.

Methods

Subarachnoid hemorrhage was induced in rats by injecting 250 μl of blood into the suprachiasmatic cistern, and gene regulation in the cerebral arteries was examined at various points in time following SAH by using quantitative polymerase chain reaction (PCR) and immunohistochemistry.

Results

Immunohistochemical findings demonstrated that SAH phosphorylates and activates p38 and ERK1/2 as well as the downstream transcription factors Elk-1 and activating transcription factor–2. The pattern of activation consists of a rapid phase within the first few hours and a late phase that occurs from 24 to 48 hours. Activation is followed by an increase in the transcription of the inflammatory and ECM-related genes (IL6, TNFα, IL1β, CXCL1, CXCL2, CCL20, MMP8, MMP9, MMP13, and iNOS), as demonstrated using real-time PCR. For MMP13 and iNOS, the changes in transcription were translated into functional proteins, as revealed on immunohistochemistry.

Conclusions

Activation of the p38 and ERK1/2 signaling pathways and their downstream transcription factors can explain the increase in the transcription of the genes studied. This increase and the subsequent augmentation in protein levels suggest that the inflammatory response may in part explain the remodeling that occurs in cerebral arteries following SAH.

Advances in vasospasm treatment and prevention

Outcome after aSAH depends on several factors, including the severity of the initial event, perioperative medical management, surgical variables, and the incidence of complications. Cerebral vasospasm (CV) is ure to consistently respond to treatment, emphasizing the need for further research into the underlying mechanisms of SAH-induced cerebrovascular dysfunction. To this end, our paper reviews the relevant literature on the main therapies employed for CV after aSAH and discusses possible avenues for future investigations. Current management of this condition consists of maximal medical therapy, including triple H regimen and oral administration of calcium antagonists, followed by endovascular balloon angioplasty and/or injection of vasodilatory agents for refractory cases. As the precise pathophysiology of CV is further elucidated, the development of promising investigational therapies will follow.

Cerebral vasospasm after resection of an esthesioneuroblastoma: case report and literature review

BACKGROUND

In the last 40 years, there were several reports of symptomatic cerebral vasospasm occurring after resection of brain neoplasms. In most cases, delay in recognition of this complication leads to significant neurologic deterioration postoperatively, regardless of the outcome of surgery. We illustrate in this report a case of cerebral vasospasm after resection of an esthesioneuroblastoma in an adult patient. This is the first report of vasospasm after resection of this neoplasm.

CASE DESCRIPTION

A 41-year-old woman presented with complaints of headache, dizziness, visual blurring, and diplopia of several-day duration. Funduscopic examination revealed papilledema. Radiological studies revealed a large frontal lobe mass extending through the cribriform plate into the ethmoid sinus with accompanying brain edema. The patient underwent a craniotomy for resection of the neoplasm. Pathological findings were consistent with a high-grade esthesioneuroblastoma. Eleven days postoperatively, the patient's neurologic status declined. Diffusion-weighted MRI of the brain showed an infarct involving mainly the left PCA as well as branches of the left anterior and middle cerebral arteries. Angiography revealed narrowing of the corresponding cerebral vessels consistent with vasospasm. Hypervolemic, hypertensive therapy with nimodipine and corticosteroids were instituted. The patient initially improved but was left with a right homonymous hemianopsia upon discharge 23 days postoperatively.

CONCLUSIONS

Delayed neurologic deficit from vasospasm after tumor resection is a complication that is being reported in increasing numbers. These cases involved tumors in or adjacent to the basal cisterns, or surgical approaches that increase the propensity of blood to accumulate intraoperatively or postoperatively in a specific pattern in the basal subarachnoid space. A high index of suspicion for vasospasm should be maintained in patients who develop delayed neurologic deficit, especially when there is evidence of profuse intraoperative bleeding or postoperative blood in the basal cisterns. Early recognition of this phenomenon and early institution of proper therapy can reverse some or all of the neurologic deficit and improve the overall outcome for these patients.