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.

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.

Interleukin 6 in cerebrospinal fluid is a biomarker for delayed cerebral ischemia (DCI) related infarctions after aneurysmal subarachnoid hemorrhage.

Interleukin 6 (IL-6) is a prominent proinflammatory cytokine and has been discussed as a potential biomarker for delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage. In the present study we have analyzed the time course of serum and cerebrospinal fluid (CSF) IL-6 levels in 82 patients with severe aneurysmal subarachnoid hemorrhage (SAH) requiring external ventricular drains in correlation to angiographic vasospasm, delayed cerebral ischemia, secondary infarctions and other clinical parameters. We observed much higher daily mean IL-6 levels (but also large interindividual variations) in the CSF than the serum of the patients with a peak between days 4 and 14 including a maximum on day 5 after SAH. Individual CSF peak levels correlated significantly with DCI (mean day 4-14 peak, DCI: 26,291 ± 24,159 pg/ml vs. no DCI: 16,184 ± 13,163 pg/ml; P = 0.023). Importantly, CSF IL-6 levels differed significantly between cases with DCI and infarctions and patients with DCI and no infarction (mean day 4-14 peak, DCI with infarction: 37,209 ± 26,951 pg/ml vs. DCI, no infarction: 15,123 ± 11,239 pg/ml; P = 0.003), while findings in the latter patient group were similar to cases with no vasospasm (mean day 4-14 peak, DCI, no infarction: 15,123 ± 11,239 vs. no DCI: 15,840 ± 12,979; P = 0.873). Together, these data support a potential role for elevated CSF IL-6 levels as a biomarker for DCI with infarction rather than for DCI in general. This fits well with a growing body of evidence linking neuroinflammation to ischemia and infarction, but (together with the large interindividual variations observed) limits the diagnostic usefulness of CSF IL-6 levels in SAH patients.

A case of anti-MDA5 antibody-positive dermatomyositis developing reversible cerebral vasospasm syndrome successfully treated by multi-immunosuppressant combination including mycophenolate mofetil.

A 39-year-old woman admitted with multiple joint pain, hand rashes, and shortness of breath was diagnosed with anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (DM) with interstitial pneumonia (IP). Because of progressive dyspnoea and hypoxaemia, her IP was considered rapidly progressive interstitial lung disease. Initially, prednisolone 60 mg/day, cyclosporine A (CyA), and intravenous cyclophosphamide (IVCY) were initiated. A few days following the initiation of treatment, she experienced massive thunderclap headache, which was diagnosed as reversible cerebral vasospasm syndrome based on the findings of contraction in cerebral arteries with brain magnetic resonance imaging. Treatment with CyA and IVCY was discontinued, and diltiazem and mycophenolate mofetil (MMF) were initiated as an alternative immunosuppressant. Considering IVCY as the cause of Reversible cerebral vasospasm syndrome based on her clinical course, tacrolimus was commenced, which improved both DM and IP. DM patients who are anti-MDA5 antibody-positive are considered to have poor prognosis and require aggressive immunosuppressive treatments. In patients experiencing adverse events with standard IVCY, MMF with high-dose steroids and alternative calcineurin inhibitor should be considered.

Potential role of CD34 in cerebral vasospasm after experimental subarachnoid hemorrhage in rats.

Inflammatory responses have been implicated in the elaboration of several forms of central nervous system injury, including cerebral vasospasm after subarachnoid hemorrhage (SAH). A critical event participating in such responses is the recruitment of circulating leukocytes into the inflammatory site. CD34 is a key adhesion molecule responsible for recruitment of monocytes/macrophages and the attachment of leukocytes to endothelial cells. However, it has not been investigated whether, and to what degree, CD34 is induced by SAH and also the role of CD34 in the pathogenesis of cerebral vasospasm following SAH remains unknown. Experiment 1 aimed to investigate the timecourse of the CD34 expression in the basilar artery after SAH. In experiment 2, we chose the maximum time point of vasospasm (day 3) and assessed the effect of monoclonal antibody against CD34 on regulation of cerebral vasospasm. As a result, the elevated expression of CD34 was detected in the basilar artery after SAH and peaked on day 3. After intracisternal administration of CD34 monoclonal antibody, the vasospasm was markedly attenuated after blood injection on day 3. Our results suggest that CD34 is increasingly expressed in a parallel time course to the development of cerebral vasospasm in a rat experimental model of SAH and administration of the specific CD34 antibody could prevent or reduce cerebral vasospasm caused by SAH.

Plasma Levels of IL-6, IL-8, IL-10, ICAM-1, VCAM-1, IFNγ, and TNFα are not Associated with Delayed Cerebral Ischemia, Cerebral Vasospasm, or Clinical Outcome in Patients with Subarachnoid Hemorrhage.

BACKGROUND: Delayed cerebral ischemia (DCI) is a serious and frequent complication following subarachnoid hemorrhage (SAH). The pathophysiology behind DCI remains poorly understood, but inflammation has been proposed to play a significant role. This study investigated the relationship between plasma levels of some of the most important inflammatory markers and DCI, cerebral vasospasm, and functional outcome in patients with SAH. METHODS: In 90 patients with SAH, interleukin-6, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, high sensitivity C-reactive protein (HsCRP), interleukin-8, interleukin-10, interferon gamma, and tumor necrosis factor alpha were measured in peripheral blood day 3 and day 8 after SAH. Any occurrence of DCI or infection was recorded, and computed tomography angiography was performed on day 8. Clinical outcome was assessed after 3 months. RESULTS: HsCRP on day 3 was higher in patients with angiographic vasospasm (P = 0.003), and HsCRP on day 8 was higher in patients with poor outcome (P = 0.014). No association with DCI, vasospasm, or outcome was found for any of the remaining analyzed substances. CONCLUSIONS: High plasma levels of HsCRP were significantly associated with angiographic vasospasm and clinical outcome. Plasma levels of interleukin-6, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, interleukin-8, interleukin-10, interferon gamma, and tumor necrosis factor alpha were not associated with DCI, angiographic vasospasm, or clinical outcome at 3 months.

Intranasal administration of E-selectin to induce immunological tolerization can suppress subarachnoid hemorrhage-induced vasospasm implicating immune and inflammatory mechanisms in its genesis.

Evidence that inflammatory and immune mechanisms may have a critical role in the development of vasospasm after subarachnoid hemorrhage is accumulating. We examined, therefore, whether induction of immunological tolerance to the adhesion molecule that is uniquely expressed on activated endothelium, E-selectin, could inhibit the vasospasm provoked by subarachnoid blood in a rat subarachnoid hemorrhage model. We found that intranasal instillation of E-selectin every other day for 10 days on a mucosal tolerization schedule suppressed delayed type hypersensitivity to E-selectin confirming tolerance to that molecule and markedly suppressed basilar artery spasm after subarachnoid hemorrhage. The results of this proof-of-concept study suggest that agents that can mimic the local effects of the mediators of mucosal tolerance could have therapeutic potential for the management of post-subarachnoid hemorrhage vasospasm.

Activation of Cytotoxic Natural Killer Cells After Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: Cell-mediated inflammation is critical in the development of cerebrovascular complications after aneurysmal subarachnoid hemorrhage. We analyzed the course for activated CD16brightCD56dim cytotoxic natural killer (NK) cells in cerebrospinal fluid of 15 patients. METHODS: Patients were classified by occurrence of cerebral vasospasm (CV) and delayed cerebral ischemia. NK were monitored by flow cytometry between day 1 and 14 after hemorrhage. RESULTS: Twelve patients (80%) developed CV with a mean day of detection at 3.9 ± 1.6. In those patients, cell count for NK increased from 1.40 ± 1.42 cells/µL on day 1 to a peak of 11.66 ± 11.56 cells/µL on day 6.1 ± 2.9 (P = 0.001). An increase of mean cerebral blood flow velocity in transcranial Doppler from 71.33 ± 12.93 cm/second to 166.20 ± 20.19 cm/second (P < 0.01) and an increase in number of vascular axes affected by CV was detected (P < 0.01). In patients with grade 3 CV (n = 4, 33.3%), activated NK counts were significantly higher than in patients who did not have CV (23.18 ± 13.92 cells/µL vs. 0.02 ± 0.01 cells/µL; P = 0.029). NK counts were significantly different between patients with grade 1 and grade 3 CV (P = 0.04). Patients who did not have CV who showed low NK counts achieved better functional outcome (Glasgow Outcome Scale [GOS] score, 4.6 ± 0.6) at discharge than did patients with CV grade 2 (GOS score, 3.3 ± 0.5) and CV grade 3 (GOS score, 2.3 ± 0.5) who showed increased NK cell counts (CV grade 0 vs. CV grade 2, P = 0.048; CV grade 0 vs. CV grade 3, P = 0.001). Activated CD16brightCD56dim cytotoxic NKCSF cell counts showed a mean maximum (14.15 ± 12.21 cells/µL) when delayed cerebral ischemia occurred. CONCLUSIONS: The increase of activated CD16brightCD56dim cytotoxic NK cells in cerebrospinal fluid after aneurysmal subarachnoid hemorrhage suggests an increased risk of CV and delayed cerebral ischemia.

Study on the expression and mechanism of inflammatory factors in the brain of rats with cerebral vasospasm.

OBJECTIVE: We investigated the significance of IL-1 and ICAM-1 in rat's subarachnoid hemorrhage (SAH) cerebral vasospasm (CVS) model. MATERIALS AND METHODS: A total of 30 Sprague-Dawley (SD) rats were randomly divided into the SAH group and the Sham group. Cisterna magna auto blood injection was used to prepare the CVS models. We studied and compared changes in the basilar arteries diameters before and after SAH. We measured the cerebrovascular inner diameter before and after SAH modeling using the ultrasound. ELISA method was used to measure the expression of IL-1 and ICAM-1 in peripheral blood. The expression of MAPK and P38 in the brain was tested using Western blot. Brain cells apoptosis was studied using TUNEL method. RESULTS: Cerebrovascular inner diameter reduced significantly in the SAH group as compared to the control group. The expression of IL-1 and ICAM-1 increased significantly after 48 hours. Compared to the Sham group, p-38 and p-MAPK expression levels in the SAH group increased significantly after 48 hours. Results showed that 48 hours after the operation, the level of apoptosis was significantly higher in the SAH group. IL-1 and ICAM-1 expression levels were associated with a P38-MAPK signal pathway in the brain. p38 and MAPK activation were closely related to apoptosis in the cortex. CONCLUSIONS: We suggest that the cerebral basilar vasospasm was occurred in rats 48 hours after ASH onset, with an increase in IL-1 and ICAM-1 expression and brain cells apoptosis.

[Migraine in SLE: role of antiphospholipid antibodies and Raynaud's phenomenon]. / Emicrania nel LES: ruolo del fenomeno di Raynaud e degli anticorpi antifospolipidi.

OBJECTIVES: To determine the role of antiphospholipid antibodies (aPL) and of Raynaud's phenomenon (RP) in the development of migraine in patients with systemic lupus erythematosus (SLE). METHODS: 50 unselected SLE patients and 20 rheumatoid arthritis (RA) controls underwent an interview to define the presence of migraine according to the guidelines of the International Headache Society (1988). Serological tests for aPL were performed in all patients. SLE patients were divided according to positivity for RP and/or aPL into 4 subsets: R-/aPL-, R-/aPL+, R+/aPL- and R+/aPL+. Data were analysed using Fisher's exact test, Chi-square test and U Mann-Whitney test. RESULTS: SLE and RA patients were similar for demographic and clinical features; aPL positivity was found in a greater proportion of SLE patients versus RA controls (68% vs 25%, p=0.0036). 31 of the 50 lupic patients (62%) and 7 of the 20 RA controls (35%) suffered from migraine (OR=3, CI:1-8.9). Among SLE and RA patients, migraine was associated with aPL positivity (p=0.027 and p=0.019). Analysing the combined effect of aPL and RP on migraine, in R+/aPL+ patients we detected an higher frequency of migraine (85.7%) with respect to the patients negative for these two features (27%, p=0.0051, OR=16, CI:2.2-118) and to the patients positive only for aPL (65%, p=0.0031, OR=6.2, CI:1.2-32). CONCLUSIONS: Migraine in SLE and RA associates with aPL positivity. The simultaneous presence of RP increases by 2,5 times the probability of having migraine, suggesting that cerebral vasospasm might be more common in patients with peripheral vasospasm, given the presence of aPL.

Role of p38 mitogen-activated protein kinase on cerebral vasospasm after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Inflammatory cytokines are involved in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). This study was conducted to examine the role of p38 mitogen-activated protein kinase (MAPK) in the development of vasospasm and cytokine production. METHODS: We measured the expression levels of genes and proteins related to inflammation in human vascular smooth muscle cells (hVSMCs) treated with hemolysate and FR167653 (FR) (1 micromol/L), a selective p38MAPK inhibitor, for 48 hours by TaqMan real-time reverse transcription-polymerase chain reaction (RT-PCR) and ELISA. Twenty-one dogs were assigned to 3 groups of 7 animals: control, placebo, and FR-treated (1 mg/kg/d) groups in a double-hemorrhage model. The effects were assessed through the caliber of the basilar artery, and the changes in gene expressions and the activation of p38MAPK were assessed by Western blot analysis. RESULTS: Treatment of hVSMCs with hemolysate induced significant upregulation of interleukin (IL)-1alpha, IL-1beta, and IL-8 gene and protein expressions, which was suppressed significantly with FR. The mean vessel caliber on day 7, as a percentage of that of day 0, was 49% in the placebo, and 74% in the FR group (P=0.0001). The gene expression levels of IL-1alpha, IL-1beta, and IL-8 in the arterial wall were extremely elevated in the placebo, and significantly suppressed in the FR group (P=0.0027, 0.0002, and 0.0073). p38MAPK phosphorylation was stimulated in the placebo and hemolysate in vitro, and suppressed in the FR group. CONCLUSIONS: These results suggest that p38MAPK is activated in the arterial wall after SAH, leading to the development of vasospasm, possibly through the upregulation of inflammatory cytokines.

Quantitative analysis of gene expressions related to inflammation in canine spastic artery after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The possible role of inflammatory reaction of the cerebral artery in the pathogenesis of cerebral vasospasm has been noted in recent studies. We quantitatively measured the levels of expression of genes related to inflammation in the spastic artery in a canine double-hemorrhage model. METHODS: Twenty dogs were assigned to 4 groups: group D0, control; group D2, dogs killed 2 days after cisternal injection of blood; group D7, dogs given double cisternal injections of blood and killed 7 days after the first injection; and group D14. Angiography was performed twice: on the first day and before the animals were killed. Total RNA was extracted from the basilar artery. The expressions of interleukin (IL)-1alpha, IL-6, IL-8, IL-10, tumor necrosis factor-alpha, E-secretin, fibronectin, intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule-1, transforming growth factor-ss, basic fibroblast growth factor, and collagen types I, III, and IV were examined with TaqMan real-time quantitative reverse transcription-polymerase chain reaction. RESULTS: Prolonged arterial narrowing peaking on 7 day was observed. There was a significant difference in vessel caliber between D0, D2, D7, and D14 groups (P:<0.0001). There were significant differences in mRNA expression in the basilar artery for IL-1alpha, IL-6, IL-8, ICAM-1, and collagen type I between D0, D2, D7, and D14 groups (P:=0.0079, 0. 0196, 0.0040, 0.0017, and <0.0001, respectively). The average level of mRNA was highest in D7 for IL-1alpha, IL-6, IL-8, and ICAM-1 (17-, 16-, 131-, and 1.7-fold compared with those of D0, respectively) and in D14 for collagen type I (10.9-fold). CONCLUSIONS: Increased expression of genes related to inflammation in the spastic artery suggests that inflammatory reaction of the cerebral artery is associated with sustained contraction.

Expression of interleukin-1 beta in lipopolysaccharide stimulated monocytes derived from patients with aneurysmal subarachnoid hemorrhage is correlated with cerebral vasospasm.

Cerebral arterial vasospasm is a frequent complication after aneurysmal subarachnoid hemorrhage (SAH). Immunological activation may affect the development of vasospasm. This study measured the cytokines released from lipopolysaccharide-stimulated monocytes of SAH patients. We measured cerebral artery diameters before and after surgery for SAH. The activation index of interleukin-1 beta (IL-1 beta), but not tumor necrosis factor-alpha (TNF-alpha), was higher in patients with symptomatic vasospasm (5.6+/-1.7; n=11) than in patients without (1.8+/-0.4; n=11) (P=0.039). Furthermore, the IL-1 beta activation index was correlated with the degree of the postoperative angiographic vasospasm (correlation coefficient=-0.66, P=0.007). Individual variation in systemic immune activation, measured by monocyte-derived IL-1 beta expression levels after stimulation, may be associated with the development of vasospasm after aneurysmal SAH.

Cerebral vasospasm after subarachnoid hemorrhage: putative role of inflammation.

Cerebral vasospasm is a common, formidable, and potentially devastating complication in patients who have sustained subarachnoid hemorrhage (SAH). Despite intensive research efforts, cerebral vasospasm remains incompletely understood from both the pathogenic and therapeutic perspectives. At present, no consistently efficacious and ubiquitously applied preventive and therapeutic measures are available in clinical practice. Recently, convincing data have implicated a role of inflammation in the development and maintenance of cerebral vasospasm. A burgeoning (although incomplete) body of evidence suggests that various constituents of the inflammatory response, including adhesion molecules, cytokines, leukocytes, immunoglobulins, and complement, may be critical in the pathogenesis of cerebral vasospasm. Recent studies attempting to dissect the cellular and molecular basis of the inflammatory response accompanying SAH and cerebral vasospasm have provided a promising groundwork for future studies. It is plausible that the inflammatory response may indeed represent a critical common pathway in the pathogenesis of cerebral vasospasm pursuant to SAH. Investigations into the nature of the inflammatory response accompanying SAH are needed to elucidate the precise role(s) of inflammatory events in SAH-induced pathologies.

Neutralizing antibody against interleukin-6 attenuates posthemorrhagic vasospasm in the rat femoral artery model.

OBJECTIVE: The degree to which inflammation contributes to the development of posthemorrhagic vasospasm is controversial. In the present study, we investigated the relationship between various inflammatory cytokines (tumor necrosis factor-alpha, interleukin [IL]-1alpha, IL-1beta, and IL-6) and the development of experimental vasospasm. METHODS: Posthemorrhagic vasospasm was produced in the rat femoral artery model. A latex pouch was placed around each femoral artery, and one pouch was injected with autologous blood and the other with saline as an internal control. Animals were killed at various time points (1 h to 16 d) after surgery (blood exposure), and the degree of vasospasm was assessed by image analysis of artery cross sectional area. Levels of inflammatory cytokines were determined by enzyme-linked immunosorbent assay, and the ability of a polyclonal antibody against rat IL-6 to inhibit vasospasm was tested. RESULTS: The rat femoral artery model produced a biphasic vasospasm response, with maximal chronic delayed vasospasm occurring at 8 days after hemorrhage. Enzyme-linked immunosorbent assay revealed a significant increase in IL-6 concentrations in blood-exposed arteries relative to saline-exposed arteries at multiple time points (6, 12, 24, and 48 h) after hemorrhage (P < 0.0001). A relative increase in IL-1alpha levels was noted at 24 hours (P < 0.01). IL-1beta levels were similarly elevated in both blood- and saline-exposed arteries, and tumor necrosis factor-alpha levels were not detectable. Administration of a neutralizing polyclonal antibody against rat IL-6 directly into the blood-exposed periarterial pouch at the time of initial surgery resulted in a dose-dependent reduction in the degree of vasospasm compared with vehicle-treated controls at 8 days after hemorrhage (P < 0.05). CONCLUSIONS: These results indicate that cytokine-mediated inflammation is active in the setting of posthemorrhagic vasospasm produced by the rat femoral artery model. In particular, the profound increase in IL-6 levels after exposure to hemorrhage and the ability of a polyclonal antibody against IL-6 to reduce vasospasm suggest that IL-6 may play a prominent role in the development of vasospasm in this model.

Inhibition of vasospasm with lymphocyte function-associated antigen-1 monoclonal antibody in a femoral artery model in rats.

OBJECT: The authors have previously shown that a monoclonal antibody (mAb) that recognizes intercellular adhesion molecule-1 (ICAM-1), also known as CD54, when administered systemically inhibits experimental vasospasm in a rat femoral artery model, suggesting that ICAM-1 and leukocyte-endothelial adhesion play a crucial role in the molecular chain of events leading to posthemorrhagic vasospasm. In this report the authors confirm this hypothesis with mAbs directed against lymphocyte function-associated antigen-1 ([LFA-1] CD11a/CD18), the molecule on the surface of leukocytes that interacts with ICAM-1. METHODS: Femoral arteries in 38 Sprague-Dawley rats were isolated and exposed to autologous blood. Twenty-nine animals were then randomized into three groups and received intraperitoneal injections of anti-LFA-1 mAb (10 rats), anti-ICAM-1 mAb (10 rats), or an isotype-matched control mAb (nine rats). Injections were administered at 3 hours and 3, 6, and 9 days after surgery. Before their deaths, six animals underwent spleen harvest, and splenocytes were used in fluorescence-activated cell sorter (FACS) analysis to verify saturation of appropriate binding sites. Animals were killed at 12 days and vessels were harvested for histological study and measurement of the luminal cross-sectional area. Nine animals were randomized as earlier, killed 24 hours after a single injection of mAb, and evaluated for periadventitial infiltration of granulocytes and macrophages. Results of FACS analysis demonstrated saturation of both LFA-1 and ICAM-1 binding sites in animals treated with the respective mAb. The mean ratios of blood-exposed to saline-exposed luminal cross-sectional areas (expressed as the percentage of lumen patency) were 90.1 +/- 5.8% (mean +/- standard error of the mean) for animals treated with the anti-LFA-1 mAb (p = 0.0218), 94.2 +/- 3.3% for animals treated with the anti-ICAM-1 mAb (p = 0.0067), and 62 +/- 7.4% for animals treated with the isotype-matched control mAb. Macrophage and granulocyte counts in the periadventitial region were 39.5 +/- 3.2/hpf for animals treated with anti-LFA-1 mAb (p = 0.001), 42 +/- 3.7/hpf for animals treated with anti-ICAM-1 mAb (p = 0.003), and 72.2 +/- 6.2/hpf for control animals. CONCLUSIONS: The systemic administration of anti-LFA-1 or anti-ICAM-1 mAb initiated 3 hours after exposure to autologous blood inhibits the development of delayed chronic vasospasm at 12 days in a rat femoral artery model and leads to a significant reduction in periadventitial inflammatory cells at 24 hours. The authors conclude that blocking the migration of inflammatory cells across the endothelial surface of an artery after adventitial exposure to blood prevents the initiation of biological cascades necessary for the subsequent development of chronic vasospasm.

Depletion of Ly6G/C(+) cells ameliorates delayed cerebral vasospasm in subarachnoid hemorrhage.

BACKGROUND: The etiology of delayed cerebral vasospasm (DCV) after aneurysmal subarachnoid hemorrhage (SAH) has remained elusive. Growing evidence supports a role for inflammation in the pathogenesis of DCV. We showed that CSF neutrophils predict which patients will develop DCV. METHODS: We evaluated a murine model of SAH to test the hypothesis that myeloid cells are required for the cerebral damage associated with DCV. RESULTS: SAH was associated with decreased middle cerebral artery caliber on day 1 which normalized at day 3 and recurred at day 6. In addition, behavioral testing with a Barnes maze showed executive dysfunction that progressively worsened after the seventh day post hemorrhage. To test the role of innate immune responses, we administrated a myeloid cell-depleting monoclonal antibody against Ly6G/C prior to experimental SAH. Myeloid cell depletion ameliorated angiographic vasospasm measured by MCA vessel caliber and normalized behavioral testing. CONCLUSION: Our findings support the role of Ly6G/C(+) cells in the development of DCV after SAH and suggest that immune modulation of neutrophils or other Ly6G/C(+) cells may be a strategy for the prevention of DCV.

Expression of monocyte chemoattractant protein-1 in the cerebral artery after experimental subarachnoid hemorrhage.

Monocyte chemoattractant protein-1 (MCP-1) is a potent chemokine that plays an important role in the recruitment of macrophages. Although previous studies have demonstrated that MCP-1 has been shown to be involved in the damaging inflammatory processes associated with stroke, infection, neoplasia, and others in the central nervous system, the role of MCP-1 in the cerebral artery after experimental subarachnoid hemorrhage (SAH) in rats has been largely unexplored. This study was undertaken to investigate the expression of the MCP-1 in SAH model and to clarify the potential role of MCP-1 in cerebral vasospasm. A total of 80 rats were randomly divided into four groups: control group; day 3, day 5, and day 7 groups. Day 3, day 5, and day 7 groups were all SAH groups. The animals in day 3, day 5 and day 7 groups were subjected to injection of autologous blood into cisterna magna twice on day 0 and day 2 and were killed on days 3, 5, and 7, respectively. Cross-sectional area of basilar artery was measured and the MCP-1 expression was assessed by real-time PCR, Western blot and immunohistochemistry. The cross-sectional area of basilar artery was found to be 85,373+/-8794 mum(2) in control group, 59,210+/-7281 mum(2) in day 3, 50,536+/-6519 mum(2) in day 5, and 66,360+/-7452 mum(2) in day 7, respectively. The basilar arteries exhibited vasospasm after SAH and became more severe on day 5. The elevated mRNA and protein of MCP-1 were detected after SAH and peaked on day 5. MCP-1 is increasingly expressed in a parallel time course to the development of cerebral vasospasm in a rat experimental model of SAH and these findings might have important implications during the administration of specific MCP-1 antagonists in order to prevent or reduce cerebral vasospasm caused by SAH.

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.