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Stroke is the leading cause of disabilities and cognitive deficits, accounting for 5.2% of all mortalities worldwide. Transient or permanent occlusion of cerebral vessels leads to ischemic strokes, which constitutes the majority of strokes. Ischemic strokes induce brain infarcts, along with cerebral tissue death and focal neuronal damage. The infarct size and neurological severity after ischemic stroke episodes depends on the time period since occurrence, the severity of ischemia, systemic blood pressure, vein systems and location of infarcts, amongst others. Ischemic stroke is a complex disease, and neuronal injuries after ischemic strokes have been the focus of current studies. The present review will provide a basic pathological background of ischemic stroke and cerebral infarcts. Moreover, the major mechanisms underlying ischemic stroke and neuronal injuries are summarized. This review will also briefly summarize some representative clinical trials and up‑to‑date treatments that have been applied to stroke and brain infarcts.

The presence of disease-specific antigens and autoantibodies in the sera of patients with atherosclerosis-related diseases has been widely reported and is considered to result from inflammation of the arterial wall and the involvement of immune factors. The aim of this study was to identify a novel antibody in patients with ischemic stroke by serological identification of antigens using recombinant cDNA expression cloning from patients who had a transient ischemic attack (TIA). We identified the serpin peptidase inhibitor, clade E member 1 (SERPINE1), as a candidate antigen. The serum anti-SERPINE1 antibody levels quantified using amplified luminescent proximity homogeneous assay-linked immunosorbent assay were significantly higher in patients with ischemic stroke, including those with acute cerebral infarction (aCI), TIA, and chronic cerebral infarction, than in healthy donors. The antibody levels were strongly associated with old age, female sex, and presence of hypertension, diabetes mellitus, and cardiovascular disease. Age and intima-media thickness of the carotid artery were positively correlated with antibody levels, which suggests that SERPINE1 may reflect the progression of atherosclerosis. In a multivariate analysis, SERPINE1 antibody level was an independent predictor of aCI. Thus, the serum levels of anti-SERPINE1 antibody could potentially serve as a biomarker of atherothrombotic infarction., (© 2021. The Author(s).)

Aim: Systemic lupus erythematosus (SLE) is a prototype autoimmune disease characterized by circulating autoantibodies and immune complexes involving virtually every organ of the body. However, with respect to central nervous system (CNS), the mechanism of injury is still debated as complement mediated or thrombo-ischemic in nature. We studied the spectrum of neuropathological changes in twelve autopsy cases of SLE and evaluated the role of immune-complexes and complement activation in contributing to the thrombo-ischemic injury and correlated these features with clinical profile., Methods: Autopsy records of all cases of SLE over a period of 20 years (2000-2019) were reviewed. Clinical history including neuropsychiatric symptoms and detailed histopathological analysis was performed. Direct immunofluorescence for IgM, IgG, IgA, C1q, C3, C4d, Kappa, Lambda and immunohistochemistry for C5b-9 was performed on lesional areas in paraffin embedded brain sections. Control tissue from brain was taken from two patients who died of sudden cardiac event., Results: Our cohort comprised of 12 cases with age range from 12 to 40 years and all were female patients. Microinfarction and vasculopathy seen in eight cases were the commonest findings. Four cases with microinfarcts had non-bacterial thrombotic endocarditis in heart. Microthrombi adjacent to microinfarcts were seen in 4 cases. Variable deposition of immunoglobulins (predominantly IgG) and complements (C1q, C3, C4d) was evident in cortical arterioles (2 cases) and small capillaries (1 case). Neurological symptoms were seen in four cases, of which, three had associated invasive fungal infection with secondary vasculitis. Active lupus vasculitis was identified in a single case. C5b-9 immunoexpression was not detected in any of the cases., Conclusions: Our study adds observational data to the existing literature that the predominant neuropathological features of SLE are related to thrombo-ischemic injury and small vasculopathic changes. Only in a minor subset (25%), it is mediated by immune-complexes and complements. Immune-complex deposition on immunofluorescence in cortical vessels (cerebral lupus vasculopathy) is a novel finding which has not been reported earlier., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objective: This study set out to investigate the relationships between the neutrophil-to-albumin ratio (NAR) in the early stages of aneurysmal subarachnoid hemorrhage (aSAH) and the occurrence of delayed cerebral ischemia (DCI)., Methods: A total of 439 patients with aSAH were included in this retrospective study. NAR assessment was conducted on admission. The relationship between NAR and DCI was analyzed., Results: Eighty-four patients (23.7%) experienced DCI. NAR levels were significantly higher in patients with DCI after aSAH than without DCI (median [interquartile range] 0.350 [0.274-0.406] vs. 0.240 [0.186-0.300]; P < 0.001). NAR levels were correlated with World Federation of Neurological Surgeons (WFNS) grade and modified Fisher (mFisher) grade (r = 0.505 and 0.394, respectively). NAR and mFisher grade were the independent predictors of DCI. Under receiver operating characteristic curve, NAR levels exhibited a significant discriminatory capability (area under the curve [95% confidence interval] 0.812 [0.740-0.823]; P < 0.001). The predictive power of NAR levels was similar to mFisher grade (P > 0.05)., Conclusions: NAR, in positive correlation with the severity of hemorrhage, appears to be a novel predictive biomarker of DCI after aSAH., (Copyright © 2020 Elsevier Inc. All rights reserved.)

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.

Cerebral ischemia/reperfusion injury activates microglia, resident immune cells in the brain, and allows the infiltration of circulating immune cells into the ischemic lesions. Microglia play both exacerbating and protective roles in pathological processes and are thus often referred to as "double-edged swords." In ischemic brains, blood-borne macrophages play a role that is distinct from that of resident activated microglia. Recently, the metabolic alteration of immune cells in the pathogenesis of inflammatory disorders including cerebral infarction has become a critical target for investigation. We begin this review by describing the multifaceted functions of microglia in cerebral infarction. Next, we focus on the metabolic alterations that occur in microglia during pathological processes. We also discuss morphological changes that take place in the mitochondria, leading to functional disturbances, accompanied by alterations in microglial function. Moreover, we describe the involvement of the reactive oxygen species that are produced during aberrant metabolic activity. Finally, we discuss therapeutic strategies to ameliorate aggravative changes in metabolism., (Copyright © 2020 The Authors. Production and hosting by Elsevier B.V. All rights reserved.)

Monocyte-derived and tissue-resident macrophages are ontogenetically distinct components of the innate immune system. Assessment of their respective functions in pathology is complicated by changes to the macrophage phenotype during inflammation. Here we find that Cxcr4-CreER enables permanent genetic labeling of hematopoietic stem cells (HSCs) and distinguishes HSC-derived monocytes from microglia and other tissue-resident macrophages. By combining Cxcr4-CreER-mediated lineage tracing with Cxcr4 inhibition or conditional Cxcr4 ablation in photothrombotic stroke, we find that Cxcr4 promotes initial monocyte infiltration and subsequent territorial restriction of monocyte-derived macrophages to infarct tissue. After transient focal ischemia, Cxcr4 deficiency reduces monocyte infiltration and blunts the expression of pattern recognition and defense response genes in monocyte-derived macrophages. This is associated with an altered microglial response and deteriorated outcomes. Thus, Cxcr4 is essential for an innate-immune-system-mediated defense response after cerebral ischemia. We further propose Cxcr4-CreER as a universal tool to study functions of HSC-derived cells.

Background: To assess the risk of incident cardiovascular disease in patients with primary Sjögren's syndrome, overall and stratified by Ro/SSA and La/SSB autoantibody status., Methods: A cohort of patients with primary Sjögren's syndrome in Sweden (n = 960) and matched controls from the general population (n = 9035) were included, and data extracted from the National Patient Register to identify events of myocardial infarction, cerebral infarction and venous thromboembolism. Hazard ratios were estimated using cox proportional hazard regressions., Results: During a median follow-up of 9.5 years, the overall hazard ratio (HR) was 1.6 (95% CI 1.2-2.1) for myocardial infarction, 1.2 (95% CI 0.9-1.7) for cerebral infarction and 2.1 (95% CI 1.6-2.9) for venous thromboembolism. Patients positive for both Ro/SSA and La/SSB autoantibodies had a substantially higher risk of cerebral infarction (HR 1.7, 95% CI 1.0-2.9) and venous thromboembolism (HR 3.1, 95% CI 1.9-4.8) than the general population. These risks were not significantly increased in Ro/SSA- and La/SSB-negative patients. Among autoantibody-positive patients, the highest HR of cerebral infarction was seen after ≥10 years disease duration (HR 2.8, 95% CI 1.4-5.4), while the HR for venous thromboembolism was highest 0-5 years after disease diagnosis (HR 4.7, 95% CI 2.3-9.3) and remained high throughout disease duration., Conclusions: Primary Sjögren's syndrome is associated with a markedly increased risk of cardiovascular disease and the presence of Ro/SSA and La/SSB autoantibodies identify the subgroup of patients carrying the highest risk. These findings suggest that monitoring and prevention of cardiovascular disease in this patient group should be considered., (© 2019 The Authors. Journal of Internal Medicine published by John Wiley & Sons Ltd on behalf of Association for Publication of The Journal of Internal Medicine.)

Background: The mechanisms of acupuncture on the treatment of cerebral infarction remain unclear, the aim of the present study was to provides a protocol of systematic review and meta-analysis, with which we will collect clinical evidence to verify whether acupuncture will have an effect on reducing the levels of tumor necrosis factor α (TNF-α), C-reactive protein (CRP), interleukin-1 (IL-1), and interleukin (IL-6) after cerebral infarction based on evidence-based studies., Methods: Included studies will be retrieved according to inclusion and exclusion criteria from 5 English databases (the MEDLINE via PubMed, the Cochrane Library, Embase, the Web of Science, and Ovid database), and 4 Chinese databases (China Science and Technology Journal Database (VIP), Chinese Biomedical Literature Database (CBM), Wan-fang Database, China National Knowledge Infrastructure (CNKI)) from October 1990 to October 2017. The inflammatory factor levels of TNF-α and IL-1,IL-6,CRP will be marked as major outcomes. We will use RevMan V.5.3 software to calculate the data synthesis and will conduct meta-analysis based on the collected data., Results: The inflammatory factor levels of TNF-α and IL-1,IL-6,CRP, mortality and adverse effects will be measured and comprehensively assessed to evaluate the adjunctive effect of XBP on CHF from this systematic review and meta-analysis with current clinical evidence., Conclusion: The systematic review and meta-analysis will assess the effect of acupuncture on the expression of inflammatory factors TNF-α, IL-6, IL-1 and CRP in cerebral infarction with up-to-date clinical evidence., Prospero Registration Number: PROSPERO CRD42017078583.

Ischemic stroke is a common life-threatening disease. Epidemiological studies have shown that chronic periodontitis is closely related to ischemic stroke. However, it remains unknown whether periodontitis plays a direct role in the injury of cerebral ischemia. To explore the role of chronic periodontitis in the development process of ischemic stroke, we combined two mouse models: experimental periodontitis induced by a periodontal injection of lipopolysaccharide and ischemic stroke induced by the photothrombotic method. Alveolar bone loss and inflammatory infiltration of the periodontal tissue were found in the mice with experimental periodontitis. Periodontitis significantly increased the infarction volume, and numbers of activated microglia and astrocytes. Furthermore, an increased expression of nod-like receptor protein 3 inflammasome and interleukin-1β was detected in the peri-infarct region. We drew a conclusion that chronic periodontitis exacerbated ischemic stroke by increasing the activation of microglia/astrocytes and the expression of nod-like receptor protein 3 inflammasome and interleukin-1β. This suggested that chronic periodontitis played a role in ischemic brain injury directly through exacerbating the inflammation of the damaged brain.

Background: Immune dysregulation has long been implicated in the development of delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH)., Objective: To determine the relationship of inflammatory cell biomarkers with DCI., Methods: We evaluated 849 aSAH patients who were enrolled into a prospective observational cohort study and had a white blood cell (WBC) differential obtained within 72 h of bleed onset., Results: WBC count > 12.1 × 109/L (odds ratio 4.6; 95% confidence interval [CI]: 1.9-11, P < 0.001) was the strongest Complete Blood Count (CBC) predictor of DCI after controlling for clinical grade (P < .001), thickness of SAH blood on admission computed tomography (P = .002), and clipping aneurysm repair (P < .001). A significant interaction between clinical grade and WBC count (odds ratio 0.8, 95% CI: 0.6-1.0, P = .02) revealed that good-grade patients with elevated WBC counts (49%: 273/558) had increased odds for DCI indistinguishable from poor-grade patients. Multivariable Cox regression also showed that elevated WBC counts in good-grade patients increased the hazard for DCI to that of poor-grade patients (hazard ratio 2.1, 95% CI 1.3-3.2, P < .001). Receiver operating characteristic curve analysis of good-grade patients revealed that WBC count (area under the curve [AUC]: 0.63) is a stronger DCI predictor than the modified Fisher score (AUC: 0.57) and significantly improves multivariable DCI prediction models (Z = 2.0, P = .02, AUC: 0.73; PPV: 34%; NPV: 92%)., Conclusion: Good-grade patients with early elevations in WBC count have a similar risk and hazard for DCI as poor-grade patients. Good-grade patients without elevated WBC may be candidates to be safely downgraded from the intensive care unit, leading to cost savings for both patient families and hospitals.

Objective: To investigate the effect of tauroursodeoxycholic acid (TUDCA) on neurological impairment induced by acute cerebral infarction (ACI) and its relevant mechanism of action., Patients and Methods: A total of 60 male Sprague-Dawley (SD) rats were randomly divided into Sham group (n = 20), ACI group (n = 20), and TUDCA group (n = 20). The rat model of ACI in middle cerebral artery was established. TUDCA was intravenously injected into rats in the TUDCA group, while an equal amount of sodium bicarbonate solution was intravenously injected into the other two groups. The blood was drawn after modeling to detect the content of serum glutamate (Glu), triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C). The degree of cerebral infarction in each experimental group was observed under an optical microscope, and the infarct area was measured and compared. The content of serum tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), and high-sensitivity C-reactive protein (hs-CRP) was detected via enzyme-linked immunosorbent assay (ELISA); mRNA and protein expressions of them were detected using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively, followed by statistical analysis. Moreover, the expression levels of serum malondialdehyde (MDA), oxidized-LDL (ox-LDL), superoxide dismutase (SOD), and glutathione peroxidase (GPX) were detected, followed by statistical analysis. The protein expressions of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), very low-density lipoprotein receptor (VLDLR), nuclear factor-κB (NF-κB), B-cell lymphoma 2-associated X protein (Bax), and caspase-3 were detected via Western blotting, and the gray value was determined, followed by statistical analysis., Results: TUDCA could improve the symptoms of neurological impairment in ACI patients, decrease the National Institute of Health Stroke Scale (NIHSS) score but increase the activity of daily living (ADL) score of patients, and significantly reduce the content of serum TG, TC, and LDL-C, showing statistically significant differences (p < 0.05). TUDCA significantly decreased the serum Glu content in ACI rats, reduced the cerebral infarction area and lowered the serum TG, TC, and LDL-C content, displaying statistically significant differences (p < 0 .05). Besides, TUDCA inhibited mRNA and protein expressions of TNF-α, IL-8, and hs-CRP, and alleviated the inflammatory response. TUDCA inhibited MDA and ox-LDL expressions, but increased SOD and GPX expressions, and relieved oxidative stress injury. In addition, TUDCA could negatively regulate Nrf2 signaling pathway, and down-regulated VLDLR and NF-κB protein expressions and expressions of apoptotic proteins (Bax and caspase-3)., Conclusions: TUDCA can alleviate the ACI-induced neurological impairment in rats through mitigating lipid peroxidation and inflammatory response and reducing apoptosis, whose relevant mechanism may be that TUDCA negatively regulates Nrf2 signaling pathway.

Epoxyeicosatrienoic acids (EETs) are produced by cytochrome P450 epoxygenases from arachidonic acid, and their rapid metabolism is mainly through soluble epoxide hydrolase (sEH). EETs exert vasodilatory, anti-inflammatory, anti-apoptotic, and pro-angiogenic effects. Administration of sEH inhibitors before or at the onset of stroke is protective, but the effects of post-treatment at reperfusion, when inflammation is augmented, has not been as well studied. We tested the hypothesis that 1-Trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl)urea (TPPU), a potent and highly selective sEH inhibitor, suppresses inflammation and protects the brain when administered at reperfusion. Vehicle or 1 mg/kg TPPU was administered at reperfusion after 90 minutes of focal ischemia and again 24 hours later. Protein expression and activity of sEH increased after reperfusion and activity was decreased by TPPU administration. TPPU decreased infarct volume by 50%, reduced neurologic deficits and improved performance on sensorimotor tasks. Furthermore, TPPU significantly lowered the mRNA expression of interleukin-1beta by 3.5-fold and tumor necrosis factor-alpha by 2.2-fold, increased transforming growth factor-beta mRNA by 1.8-fold, and augmented immunostaining of vascular endothelial growth factor in peri-infarct cortex. Thus, inhibition of sEH at reperfusion significantly reduces infarction and improves sensorimotor function, possibly by suppressing early proinflammatory cytokines and promoting reparative cytokines and growth factors.

Cerebral infarction in children is rare and often occurs secondary to moyamoya disease, hereditary coagulopathies, vasculitis, antiphospholipid antibody syndrome, heart disease, mitochondrial disease. However, in some cases, the causes of cerebral infarction is unknown. In this study, we detected increased levels of serum anti-phosphatidylcholine and anti-phosphatidylethanolamine IgG antibodies in three pediatric patients with cerebral infarction whose primary disorders are unknown by routine examination. For the five disease control patients of cerebral infarction due to other primary disorders, there was no such increase in these antibodies levels. Phosphatidylcholine and phosphatidylethanolamine are major components of the phospholipids of vascular endothelial cells, while cardiolipin is a minor component. Anti-phosphatidylcholine and anti-phosphatidylethanolamine antibodies, as well as anti-cardiolipin antibody, might also be risk factors with cerebral infarction., (Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Background: Neonatal cerebral infarction is a relatively common cause of neonatal seizures, with an incidence of at least 1:4000 live births and is associated with a high incidence of neurological sequelae. However, the pathophysiological mechanisms and predisposing factors responsible for neonatal infarction are not fully established., Patient Description: A full-term baby boy was transferred at two days of age for the treatment of a cluster of seizures. Cranial magnetic resonance imaging revealed multiple lesions compatible with acute cerebral infarction. The results of the blood tests performed to screen for thrombophilic diseases were normal for his age, and his perinatal history was unremarkable. A diagnosis of idiopathic cerebral infarction was made. Additional examination for autoimmune diseases showed that both the mother and the patient had the anti-SS-A/Ro antibody. The patient was treated with phenobarbital and has no neurological sequelae., Conclusions: This is the first report demonstrating the coexistence of neonatal cerebral infarction and neonatal lupus syndrome. Thus neonatal lupus syndrome may be an additional risk factor for neonatal stroke., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Aim: To investigate the characteristics of the peripheral T cell immune response of patients at different stages of vascular cognitive impairment (VCI)., Methods: 61 Arterial atherosclerotic cerebral infarct induced VCI patients, including 28 vascular dementia (VaD) cases, 33 no dementia (VCI-ND) cases, and 25 atherosclerotic cerebral infarct patients with normal cognitive function (CI-NC) as controls were enrolled. Peripheral CD8(+)T, CD4(+)CD25(+) Treg, CD4(+)IL-17(+) Th17 cells proportion, and IL-1β, IL-2, IL-6, IFN-γ levels, and neuropsychological function were assessed., Results: There was no difference in average age, gender ratio, years of education, and risk factors of infarct among the three groups. Peripheral CD4(+)CD25(+) Treg in VCI-ND and VaD groups were significantly lower than that in controls, and CD8(+) T cells were markedly elevated in VaD group. The IL-17(+) Th17 cell proportion did not differ significantly among three groups. IL-6 and IFN-γ expression levels in VaD group were higher than those in other two groups. The VDAS-Cog executive function subscale score was negatively correlated with CD4(+)CD25(+) Treg proportion in VCI patients, and positively correlated with IL-6 levels., Conclusion: VCI patients demonstrated a decrease in peripheral CD4(+) Treg proportion and increased IL-6 expression, and both parameters were correlated with the decline of executive functions., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system, which is characterized by autoantibodies directed against the water channel aquaporin-4 (AQP4). As one of the main water regulators in the central nervous system, APQ4 is supposed to be involved in the dynamics of brain edema. Cerebral edema seriously affects clinical outcome after ischemic stroke; we therefore aimed to investigate whether NMO-antibodies may exert the same functional effects as an AQP4-inhibitor in-vivo in acute ischemic stroke., Methods: Sixteen male Wistar rats were randomized into two groups twice receiving either purified NMO-IgG or immune globulin from healthy controls, 24 hours and 30 minutes before middle cerebral artery occlusion (MCAO) was performed. T2-weighted MRI was carried out 24 hours after MCAO., Results: MRI-examination showed a significant increase of infarct size in relation to the cerebral hemisphere volume with NMO-IgG treated animals (27.1% ± 11.1% vs. 14.3% ± 7.2%; p < 0.05) when corrected for the space-occupying effect of vasogenic edema formation and similar results without edema correction (34.4% ± 16.4% vs. 17.5% ± 9.3%; p < 0.05). Furthermore, T2-RT revealed a significant increase in cortical brain water content of the treatment group (19.5 ms ± 9.7 ms vs. 9.2 ms ± 5.2 ms; p < 0.05)., Conclusions: These results support the functional impact of NMO-antibodies and also offer an in-vivo-applicable animal model to investigate the properties of AQP4 in ischemic stroke.

Mounting evidence has suggested that inflammation associated with interleukin (IL)‑6 and T‑helper (Th)17 cells, has a role in the development of atherosclerotic cerebral infarction (ACI). However, it remains unclear which population of cells determines the levels of IL‑6, and the role of IL‑6‑secreting cells in inducing Th17 cell production. In the present study, IL‑6 levels were determined in patients with ACI, by ELISA. The percentage of CD3+T, CD4+T, CD8+T, CD11c+ dendritic cells and γδT cells were determined by flow cytometry, and the correlation between cytokine IL‑6 and γδT cells was determined by statistical analysis. An in vitro culture assay was used to determine whether γδT cells secreted high levels of IL‑6, and induced production of Th17 cells. The patients with ACI had significantly higher levels of IL‑6 and γδT cells. Furthermore, γδT cells were associated with the secretion of a high level of IL‑6 in patients with ACI. These results indicate that γδT cells are novel IL‑6‑secreting cells, which from then on were known as γδT6 cells. In addition, the novel γδT6 cells induced Th17‑cell production, and this induction was dependent on IL‑6. Novel γδT6 cells increased the induction of Th17‑cell production in patients with ACI. The results of the present study suggest that novel γδT6 cells may be a target for strategic therapies of ACI.

Progenitor cells (PCs) contribute to the endogenous repair mechanism after ischemic events. Interleukin-8 (IL-8) as part of the acute inflammatory reaction may enhance PC mobilization. Also, statins are supposed to alter number and function of circulating PCs. We aimed to investigate PC mobilization after acute ischemic stroke as well as its association with inflammatory markers and statin therapy. Sixty-five patients with ischemic stroke were enrolled in the study. The number of CD133+ PCs was analyzed by flow cytometry. Blood samples were drawn within 24 hours after symptom onset and after 5 days. The number of CD133+ PCs increased significantly within 5 days (p<0.001). We found no correlation between CD133+ PCs and the serum levels of IL-8, IL-6, or C-reactive protein (CRP). Multivariate analysis revealed that preexisting statin therapy correlated independently with the increase of CD133+ PCs (p=0.001). This study showed a mobilization of CD133+ PCs in patients with acute cerebral infarction within 5 days after symptom onset. The early systemic inflammatory response did not seem to be a decisive factor in the mobilization of PCs. Preexisting statin therapy was associated with the increase in CD133+ PCs, suggesting a potentially beneficial effect of statin therapy in patients with stroke.

The treatment of ischemic stroke is one of the great challenges in modern neurology. The localization and the size of the infarct determine the long-term disability of stroke survivors. Recent observations have revealed that stroke also alters the function of the immune system and vice versa: At the site of the infarct, a local inflammatory response develops that enhances brain lesion development. In experimental stroke, proof-of-concept studies confirm that inhibition of this immune response reduces lesion volume and improves outcome. In the peripheral blood of stroke patients, though, lymphocytopenia and monocyte dysfunction develop. These changes reflect a clinically relevant impairment of bacterial defense mechanisms because they are associated with an enhanced risk to acquire post-stroke infections. Stress hormones have been identified as important mediators of stroke-induced immune suppression. The pharmacological inhibition of beta adrenergic receptors, but not the inhibition of steroids, is effective in reducing infection and improving clinical outcome in experimental stroke; catecholamine release therefore appears causally related to stroke-induced immune suppression. Strong evidence supports the hypothesis that these immune alterations impact the clinical course of stroke patients. Thus, the development of new therapeutic strategies targeted to alter the immunological consequences of stroke appears promising. However, to date, the beneficial effects seen in experimental stroke have not been successfully translated into a clinical trial. This brief review summarizes the current understanding of the immunological consequences of ischemic stroke. Finally, we propose a concept that links the peripheral immune suppression with the development of local inflammation., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Inflammatory responses in the brain after cerebral ischemia have been studied extensively in male mice, but not female mice, thus potentially giving a less-than-accurate view of gender associated pathological processes. In humans, cerebral infarcts are typically smaller in premenopausal females than in age-matched males. In the current study, we confirmed smaller infarcts in female vs. male mice after middle cerebral artery occlusion and 96 h of reperfusion. Moreover, we explored immunological alterations related to this difference and found that the percentage of CD4+ T lymphocytes was significantly higher in spleens in males than females, with increased expression of the activation markers, CD69 and CD44. In contrast, the percentage of CD8+ T lymphocytes was significantly higher in spleens of females than males, leading to the identification of a small but distinct population of IL-10-secreting CD8+CD122+ suppressor T cells that were also increased in females. Finally, we observed that males have a greater percentage of activated macrophages/microglia in the brain than females, as well as increased expression of the VLA-4 adhesion molecule in both brain and spleen. This new information suggesting gender-dependent immunological mechanisms in stroke implies that effective treatments for human stroke may also be gender specific.

This study aims to determine whether functional polymorphism of CD40 is associated with the cerebral infarction (CI) susceptibility, and to investigate the effect of CD40 gene polymorphism on CD40 mRNA expression in PBMCs and plasma sCD40L concentration. A case-control study was performed in 402 CI patients and 693 controls. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The expressions of CD40 mRNA and plasma sCD40L concentration were determined. The distribution of TT genotype and the frequency of T allele in CI patients were significantly higher than those in the controls (P<0.05). The frequency of T allele was also significantly higher in the male subjects and the elder subjects (P<0.05) when stratified analysis was carried out. The PBMCs from CI patients showed significantly higher CD40 mRNA expression than controls (P<0.01), the CD40 mRNA expression from TT genotype was higher than other genotypes (P<0.05). TT genotype subjects also showed the highest plasma sCD40L concentration in the male CI patients (P<0.01). CD40 -1C/T polymorphism may interfere CI susceptibility, and the T allele may be associated with increased risk of CI. The CD40 -1C/T polymorphism is also a regulator of CD40 expression and plasma sCD40L concentration., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Objective: CD4(+)CD25(+) regulatory T (Treg) cells and Th17 cells play important roles in peripheral immunity. Oxidized low-density lipoprotein (ox-LDL) is an instrumental factor in atherogenesis. However, the changes of Th17/Treg cells in patients with acute cerebral Infarction (ACI) and impact on Th17/Treg by ox-LDL are not clear. Here, we examined the balance of Th17/Treg in ACI patients and the effect of ox-LDL on this balance., Materials and Methods: The frequencies of Th17 and Treg cells, key transcription factors and relevant cytokines were examined in patients with ACI, Transient ischemic attack (TIA) and controls. The correlations of cytokines, inflammatory biomarkers and ox-LDL in serum to Th17/Treg frequency, and the effects of ox-LDL on Th17/Treg cells in vitro were analyzed., Results: ACI patients have shown a significant increase of Th17 frequency, RORγt expression and Th17 related cytokines (IL-17 and IL-6 ) levels, and a clear decline of Treg frequency, Foxp3 expression, suppressive function and regulatory cytokines (IL-10 and TGF-β1) levels. Furthermore, TIA patients also have notable variation as compared to control group. Serum ox-LDL and inflammatory biomarkers were positively correlated with the frequency of Th17 cells and negatively correlated with the frequency of Treg cells. Treg and Th17 cells from ACI patients were significantly susceptible to ox-LDL-mediated alterations in vitro., Conclusions: Th17/Treg cells were imbalanced in ACI patients, and ox-LDL may contribute to this imbalance and lead to the occurrence of ACI suggesting their pathogenetic role in ACI.

Background: There is increasing evidence on complex interaction between the nervous and immune systems in patients with cerebral infarction. This study was conducted to evaluate cytotoxic function of CD8+ T lymphocytes isolated from patients with acute severe cerebral infarction. In order to determine role of immune system in stroke, peripheral blood mononuclear cells (PBMCs) were taken and cytotoxic function of CD8+ T lymphocytes were induced by virus peptides and cells were analyzed on a four-color flow cytometer. Expression of CD107a, intracellular expression of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α), and cell proliferation assay were analyzed by using carboxyl fluorescein diacetate succinimidyl ester (CFSE)., Results: A total of 30 patients with cerebral infarction and 30 healthy volunteers with an average age 57 (range, 49 to 71) years, were evaluated. The PBMCs were separated from blood samples of both, patients with cerebral infarction 6 hours after onset of stroke and healthy volunteers. After stimulation with virus peptides, CD107a expression and intracellular production of IFN-γ and TNF-α was decreased in patients with cerebral infarction as compared to healthy volunteers (p < 0.01). Degranulation analysis reported decreased expression of CD107a + in patient group as compared to healthy group, p <0.01. A mild decrease in intracellular expression of IFN-γ and TNF-α was also shown in patients without stimulation of virus peptides (p < 0.05). However, proliferation of CD8+ T lymphocytes in patients with acute severe cerebral infarction was not decreased., Conclusions: The study results indicated that cytotoxic function of CD8+ T lymphocytes were suppressed in patients with acute severe cerebral infarction. This could possibly be associated with complicated infectious diseases and neuroprotective mechanism.

Background: Antiphospholipid antibodies (aPLs) are associated with vascular occlusive events. Lupus anticoagulant (LA) and anticardiolipin antibody (aCL) are two aPLs commonly used for screening test. However, other aPLs are reported to play a role in the thrombotic events in other disorders, especially autoimmune disease. We investigated the clinical significance of the anti-annexin V antibody (aAV) in patients with acute cerebral ischemia; annexin V promotes anticoagulant activity via inhibition of prothrombin activation., Methods: A total of 187 patients with acute cerebral infarction or transient ischemic attack, and 66 control subjects were included in this prospective study. IgG type aAV was determined by enzyme-linked immunosorbent sandwich assay in the patient and control groups. The presence of LA and aCL were determined in the patient group using the usual screening method., Results: IgG aAV was detected in 26 of the 187 patients (13.9%), but only in three of the 66 control subjects (4.5%; P=0.043). Among the 26 aAV positive patients, only five patients were positive for LA or aCL. The presence of IgG aAV was significantly associated with acute cerebral ischemia: one stroke event (OR, 4.39; 95% CI, 1.21-16.01), and two or more stroke events (OR, 3.91; 95% CI, 1.09-14.07)., Conclusion: IgG aAV was detected in a significant percentage of the patients with acute cerebral ischemia compared with the control group. The presence of IgG aAV did not usually coincide with LA or aCL. Thus aAV should be considered as a possible associated factor for acute cerebral ischemia., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Studies have shown the IL-17A involvement in human ischemic stroke patients in vivo. Whether the IL-17A expression was originated from Th17 and could be stimulated by hypoxia remained unknown. Here we report the Th17 upregulation in anaerobic cultured PBMC from chronic stage patients of severe cerebral infarction. By using ELISA and FACS we examined IL-1β, IFN-γ, IL-23 and IL-17A protein levels in the supernatants and Th1/Th17 ratios in PBMC. Statistical significance of Th17 but not Th1 upregulation was proved in 6-hr anaerobic cultured patient groups (P < 0.001). Hence, Th17 might be essential in the autoimmune pathogenesis when hypoxia recurs in severe ischemic stroke patients., (© 2011 The Societies and Blackwell Publishing Asia Pty Ltd.)

Background: Chungsim-Yeunja-Tang (CYT) has been used as a medicine for cerebral infarction (CI) patients in Korea. The objective of this study was to determine precisely the effect of CYT on CI patients using peripheral blood mononuclear cells (PBMCs)., Methods: For a clinical study, 47 CI patients were identified who had taken CYT (0.01 g/kg) 3 times a day after meals for 2 weeks by oral administration. For ex vivo experiments, peripheral blood mononuclear cells (PBMCs) were isolated from CI patients. We analyzed the effect of CYT and its main components on lipopolysaccharide (LPS)-induced cytokine production and mechanism on PBMCs of CI patients by using ELISA, western blot analysis, transcription factor enzyme-linked immunoassay, and caspase assay., Results: Clinical signs of CI significantly disappeared about 2 weeks after oral administration of CYT to CI patients (P < 0.05). CYT and quercetin, an active compound of CYT, significantly inhibited LPS-induced interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α production and expression in PBMCs. CYT and quercetin also inhibited LPS-induced nuclear translocation and DNA binding activities of nuclear factor-κB and degradation of IκBα. In addition, CYT and quercetin inhibited LPS-induced IL-32 expression and caspase-1 activation., Conclusion: These results suggest a mechanism that might explain the beneficial effect of CYT in treating CI patients. Taken together, our findings indicate that inhibition of IL-32 expression and caspase-1 activation may be a novel biomarker and potential therapeutic target in CI.

Neuroprotective effect of lipoxin A(4) methyl ester (LXA(4) ME) was tested in a rat model of permanent middle cerebral artery occlusion. LXA(4) ME was administrated through intracerebroventricular injection immediately after middle cerebral artery was occluded. Administration of LXA(4) ME ameliorated neurological deficit, reduced infarct volume, attenuated histological damage, and decreased number of apoptotic neuron induced by ischemic insult. These neuroprotective effects of LXA(4) ME were associated with inhibition of neutrophil infiltration, lipid peroxidation, and astrocyte activation. In addition, LXA(4) ME also attenuated proinflammatory cytokines (TNF-alpha and IL-1beta) production. These data suggest that LXA(4) ME protects neuron against permanent cerebral ischemia by inhibiting inflammatory responses.

Introduction: The immune central nervous system (CNS) innate immune cells including microglia and macrophages play integral roles in receiving and propagating inflammatory signals. Inflammation is generally a beneficial response of an organism to infection but, when prolonged or inappropriate, it can be detrimental. Neuronal loss in acute (e.g. stroke and head injury) and chronic (e.g. multiple sclerosis and Alzheimer's disease) CNS diseases has been associated with inflammatory processes systemically and in the brain., Development: Herein we review the processes that participate in the activation of the immune system and the starting of inflammatory response after stroke, where neuronal necrotic cell death has been described. We addressed the relevance of the innate inflammatory cells that are on the CNS, as microglia and macrophages, which have an important role in receiving and spreading inflammatory signals. In addition, the inflammatory response is characterized by an increase in the levels of expression of inflammatory mediators, which regulate adhesion molecules, and increase the permeability of the blood-brain barrier. It has also been described that inflammation promotes the rapid over-expression and activation of a variety of genes, and it has been postulated that transcription factors should be studied for their potential use in therapeutics and repair. Transcriptional activation can be a double-edged sword since depending on the individual transcription factor it can induce the expression of either neuroprotective or neurotoxic genes., Conclusion: In summary, a better understanding of the different molecules mediating the immune response will allow the design of new pharmacological tools that could improve stroke treatment.

Antiphospholipid syndrome is characterized by arterial or venous thrombosis and the presence of antiphospholipid antibodies (aPL). We measured β2-GPI aCL, IgGaCL, LA, antiphosphatidyl-serine antibody (PS), and antiphosphatidyl-inositol antibody (PI) in each patient at one month after the onset of stroke. In addition, carotid artery echography was performed in patients positive for PI or PS. Among the 250 patients, 13.6% (34/250) were positive for either PI or PS, and 6.8% (17/250) were positive for both. Carotid artery echography performed on these 34 patients showed that the frequencies of increased intimal-medial thickness (IMT) of 1.1 mm or more, plaque, and carotid artery stenosis of 50% or more were all significantly higher in patients positive for antinuclear antibody than those negative for the antibody (P < .05). PI and PS are associated with antinuclear antibody and precipitation of atherosclerosis. Ischemic stroke patients with SLE frequently showed a variety of antiphospholipid-protein antibodies.

Endothelial dysfunction is the predominant manifestation of SLE. Anti-endothelial cell antibodies (AECA) are a heterogeneous group of autoantibodies directed against different antigens in endothelial cells. The objective of this study was to assess the possible correlation between the presence of AECA and ischemic stroke manifestations in SLE. The AECA titers in serum from 34 patients with SLE and acute ischemic stroke (8 men and 26 women, mean age 38.37 +/- 3.25 years) and in 32 controls (11 men and 21 women, mean age 37.52 +/- 3.86 years) were tested. The method used was ELISA. The data were expressed as mean +/- SD from indicated number of patients. Comparison between patients and controls was expressed as relative risk with its 95% confidence interval (RR[95% CI]), where lower limit > 1.0 was considered significant. All p values were determined by Fisher's exact test. A value of p < 0.05 was considered statistically significant. AECA were positive in 31 out of 34 patients, mean value 19.2 +/- 16.3 U/mL and in 8 out of 32 controls, mean value 5.5 +/- 2.6 U/mL (RR 7.154 [95% CI 2.801 to 18.274]), p < 0.0001. Patients with SLE and acute ischemic stroke tended to have higher mean values of AECA. AECA play a pivotal role in the pathogenesis of neurologic complications of SLE. AECA titers in SLE patients with acute ischemic stroke support a role for AECA as potential diagnostic marker possibly associated to cerebral manifestations of SLE patients. Further study is needed in order to clarify if AECA presence is related to systemic diseases severity and to situate their importance among other markers of endothelial dysfunction.

The immunosuppressant FK506 (1 mg/kg, i.p.) reduces the infarct size following 90 min occlusion of the middle cerebral artery (MCAo) in adult rat brain. Here we have investigated the effect of FK506 on cerebral immune cells that are considered to contribute to neurodegeneration. FK506 substantially attenuated the response of resident and peripheral immune cells following transient ischemia. Between 24 hr and 5 days after MCAo, FK506 reduced the T-cell infiltration in the infarct area as well as the presence of activated and/or phagocytic OX-18, OX-42, GSA-IB4, Iba1, and ED1 positive microglia/macrophages. FK506 also lowered the protein levels of TNFalpha and IL-2 in ischemic brain areas. Repetitive application of FK506 over 20 days attenuated the activation of microglia in the substantia nigra (SN), an area of secondary degeneration. Importantly, FK506 conferred also lasting protection of the neurons of SN; these neurons degenerate by withdrawal of neurotrophic factors from the striatum that undergoes necrotic death as part of the ischemic core. To understand the molecular basis of FK506 effects in cerebral immune cells, we determined in primary postnatal day 0/1 (P0/P1) microglia (i) the expression of the FK506 binding proteins FKBP12, FKBP52, and FKPB65 and (ii) that FK506 (1-100 ng/mL) lowered the number of resting or lipopolysaccharide stimulated microglia as well as we induced the lipopolysaccharide release of TNFalpha in a dose-dependent manner. In summary, FK506 confers rescue of brain tissue following cerebral ischemia not only by neuronal protection, but also by suppression of microglial activation and peripheral immune responses., ((c) 2009 Wiley-Liss, Inc.)

The role of DCs (dendritic cells) as potent mediators of inflammation has not been sufficiently investigated in stroke. Therefore, in the present study, circulating mDCPs (myeloid DC precursors), pDCPs (plasmacytoid DCPs) and tDCPs (total DCPs) were analysed by flow cytometry in (i) healthy controls (n=29), (ii) patients with ACI-S (asymptomatic cerebral infarction stenosis; n=46), (iii) patients with TIA (transient ischaemic attack; n=39), (iv) patients with AIS (acute ischaemic stroke; n=73), and (v) patients with AHS (acute haemorrhagic stroke; n=31). The NIHSS (National Institutes of Health Stroke Scale) and infarction size on a CT (computer tomography) scan were evaluated after stroke. In a patient subgroup, post-mortem immunohistochemical brain analyses were performed to detect mDCs (CD209), pDCs (CD123), T-cells (CD3) and HLA-DR. In AIS and AHS, the numbers of circulating mDCPs (P<0.005), pDCPs (P<0.005) and tDCPs (P<0.001) were significantly reduced. A significant inverse correlation was found between the NIHSS and circulating DCPs (P<0.02), as well as between hsCRP (high-sensitivity C-reactive protein) and circulating DCPs (P<0.001). Patients with large stroke sizes on a CT scan had significantly lower numbers of mDCPs (P=0.007), pDCPs (P=0.05) and tDCPs (P=0.01) than those with smaller stroke sizes. Follow-up analysis showed a significant recovery of circulating DCPs in the first few days after stroke. In the infarcted brain, a dense infiltration of mDCs co-localized with T-cells, single pDCs and high HLA-DR expression were observed. In conclusion, acute stroke leads to a decrease in circulating DCPs. Potentially, circulating DCPs are recruited from the blood into the infarcted brain and probably trigger cerebral immune reactions there.

Previous studies from our laboratory indicated that selective cannabinoid CB(2) agonists were able to attenuate cerebral ischemia/reperfusion (I/R) injury. The goal of current study is to further test whether this attenuation involves cerebral microcirculatory function during I/R injury. Middle cerebral artery occlusion with reperfusion (MCAO/R) was performed in male mice. A selective CB(2) agonist was administered at different dosages and different times. Cerebral infarction volume, neurological function and cerebral microcirculatory function (leukocyte/endothelial interactions, cell adhesion molecule expression and blood-brain barrier disruption) were examined in vivo and in vitro. CB(2) knockout mice were subjected to MCAO/R following same procedures. Administration of the CB(2) agonist at middle dosage exerted optimal effects in reducing cerebral infarction and improving neurological function compared with other dosage groups and control group. Treatment with the CB(2) agonist at the optimal dose was still effective when given 3 h after MCAO. Transient ischemia significantly increased leukocyte/endothelial interactions, adhesion molecules expression and blood-brain barrier disruption which were all attenuated by pre-treatment with a CB(2) agonist. CB(2) knockout mice showed larger cerebral infarction and worse neurological function compared to wide type. In conclusion, CB(2) activation contributed to protecting the brain through the attenuation of cerebral microcirculatory dysfunction during cerebral I/R injury.

Objective: According to data from animal models, complement activation plays a major role in the brain injury after acute ischemic stroke. Scarce findings are, however, available on the detection of complement activation products in stroke patients., Methods: We have measured plasma levels of the five complement activation products (C1rC1sC1inh, C4d, C3a, C5a and SC5b-9) in samples of 26 patients with ischemic stroke upon admission. Twenty-six patients with severe carotid atherosclerosis served as patient controls., Results: Levels of two activation products (SC5b-9 and C4d)) were significantly elevated in the plasma of stroke patients, SC5b-9 levels, exhibited significant positive correlation with the clinical severity of stroke, the severity of neurological deficit, as well as with the level of functional disability., Conclusion: These findings suggest that complement activation plays an active role in the development of brain infarct. The measurement of complement activation products might help to determine the clinical prognosis after acute ischemic stroke. Furthermore, there is potential usefulness of complement modulating therapy in ischemic stroke.

Background and Purpose: To investigate changes in human leucocyte antigen (HLA)-DR expression on peripheral monocytes, determine the value of predicting the development of stroke-associated infection (SAI), and determine the correlation with other conditions in critically-ill patients in the neurological intensive care unit (NICU) who suffered an acute stroke., Methods: All patients were enrolled consecutively and admitted to NICU within 24 h after the onset of symptoms. Patients were followed in order to identify whether infection developed and determine survival status within 2 weeks after the stroke. Patients were divided into stroke or control group by study design, infection or non-infection group by whether or not they had an infection, survival or death group by prognosis and cerebral infarction or cerebral haemorrhage group by stroke type. Patients in which acute stroke was excluded by head CT or MRI were admitted to general ward and were used as a control group. Blood samples were collected serially on days 1, 2, 4, 6 and 14 after stroke, then monocyte human leucocyte antigen-DR (HLA-DR) expression was determined by flow cytometry. The National Institute of Health Stroke Scale (NIHSS), Acute Physiology and Chronic Health Evaluation II (APACHEII) and Glasgow Coma Scale (GCS) scores were recorded over the course of observation., Results: Fifty-three subjects and 39 controls were enrolled in the study. On days 1, 2, 4, 6 and 14, there was a significant difference in monocyte HLA-DR expression between stroke group and control group (all P < 0.001), but no difference was found between ischaemic stroke group and haemorrhagic stroke group (all P > 0.05). The infection group compared with non-infection group did not exhibit a significant difference in HLA-DR expression on days 1 and 2 (all P > 0.05), but significant differences emerged on days 4, 6 and 14 (all P < 0.01). On days 1 and 2 the HLA-DR expression in the survival group compared with death group, was not significantly different (all P > 0.05), but differences became significant on days 4 and 6 (P < 0.01). On day 1, HLA-DR expression <62.80% had the predictive value to SAI (sensitivity 83.3%, specificity 55.2%, AUC = 0.661, P = 0.031) and on day 2, HLA-DR expression <57.83% had the predictive value to SAI (sensitivity 95.8%, specificity 79.3%, AUC = 0.907, P = 0.000) in acute stroke patients. A statistically significant inverse correlation was found between NIHSS and HLA-DR on days 2 and 4 during the observation period (all P < 0.01), but there was no statistically significant negative correlation on days 1, 6 or 14 (all P > 0.05). HLA-DR expression did not correlate with APACHEII (all P > 0.05) or GCS (all P > 0.05) during the measurement period., Conclusions: Human leucocyte antigen-DR (HLA-DR) expression decreases and sustains a dynamic change and it also relates to the severity of patient's condition in the critically-ill patients with stroke. Progressively persistent low monocyte HLA-DR expression is associated with a poor prognosis. The decline in HLA-DR expression contributes to infection in critically-acute stroke patients. Monitoring of monocyte HLA-DR expression may be useful for identifying patients suffering from acute stroke who are at high risk for infection.

The transcription factor NF-kappaB is a key regulator of hundreds of genes involved in cell survival and inflammation. There is ample evidence that NF-kappaB is activated in cerebral ischemia, mainly in neurons. Despite its well known role as an antiapoptotic factor, in cerebral ischemia NF-kappaB contributes to neuronal cell death, at least if the ischemia is severe enough to lead to irreversible brain damage. In contrast, NF-kappaB also seems to be responsible for the preconditioning effect of a transient and sublethal ischemia, perhaps by dampening its own subsequent full activation. Among the five NF-kappaB subunits, RelA and p50 are responsible for the detrimental effect in cerebral ischemia. Activation of NF-kappaB signaling is mediated by the upstream kinase inhibitor of kappaB kinase and is triggered by hypoxia, reactive oxygen species, and several inflammatory mediators. Interestingly, the complex NF-kappaB signaling pathway provides drug targets at several levels. Modulation of NF-kappaB signaling has the potential to interrupt multiple inflammatory and apoptotic mechanisms through one specific molecular target.

Cold agglutinin disease occurring with cryoglobulinemia is a rare occurrence. Here, we report a patient with mixed cryoglobulinemia that was treated with rituximab and, after response, developed an anti-Pr cold agglutinin that manifested with hemolysis and microvascular occlusion causing mesenteric ischemia and cerebral infarction. Unlike previous reports of patients with cryoglobulinemia and cold agglutinin disease, our patient did not have a detectable cryoprecipitate when his cold agglutinin manifested.

Purpose: This study was carried out to clarify the relationship of IgG phosphatidylserine-dependent anti-prothrombin antibody (aPS/PT), IgG beta 2 glycoprotein I-dependent anticardiolipin antibody (beta 2-GPI aCL), and lupus anticoagulant (LA) to cerebral infarction, using data from 93 patients who visited our hospitals., Materials and Methods: We computed the positive rates for each of IgG aPS/PT, beta 2-GPI aCL, and LA in the 93 patients with cerebral infarction, and carried out logistic regression analysis with IgG aPS/PT as the outcome variable and with beta 2-GPI aCL, LA, and each risk factor as predictor variables in order to assess the relationship of IgG aPS/PT with each factor., Results: IgG aPS/PT was more highly correlated with LA than beta 2-GPI aCL in IgG aPS/PT-positive patients with cerebral infarction. IgG aPS/PT itself appears to have high specificity as a marker for antiphospholipid syndrome (APS), because there were patients who were IgG aPS/PT-positive but both beta 2-GPI aCL- and LA-negative., Conclusion: In IgG aPS/PT-positive patients with cerebral infarction, IgG aPS/PT is more highly correlated with LA than beta 2-GPI aCL. It is also strongly associated with APS. Measurement of IgG aPS/PT in patients with cerebral infarction could be of diagnostic value.

Interleukin-6 (IL-6) exerts neuroprotective effects after cerebral ischaemia but can also exacerbate inflammation and induce neuronal death. The current study investigates the role of cerebral peroxisome proliferator-activated receptor(s) gamma (PPARgamma) in the regulation of IL-6 expression in the peri-infarct cortical tissue in rats exposed to focal cerebral ischaemia. Pioglitazone, a high-affinity PPARgamma ligand, was infused intracerebroventricularly (i.c.v.) via osmotic minipumps over a 5-day period before, during and 24 h or 48 h after middle cerebral artery occlusion (MCAO) for 90 min followed by reperfusion. The expression of PPARgamma and IL-6 in cortical tissue adjacent to the ischaemic core was studied 24 h and 48 h after MCAO. Pioglitazone augmented the ischaemia-induced upregulation of PPARgamma at both time points. Cerebral ischaemia substantially increased IL-6 expression in the peri-infarct cortical tissue. Twenty-four hours after MCAO, the majority of microglial cells/macrophages showed an intense IL-6 immunoreactivity. IL-6 was also localized in neurons, but the distribution of neurons positively stained for IL-6 at the border of the infarct was very heterogeneous. Pioglitazone effectively decreased the number of IL-6-immunoreactive cells and IL-6 protein levels at 24 h but not at 48 h after MCAO. Pioglitazone treatment reduced the infarct size and improved neurological functions. The present study demonstrates that cerebral PPARgamma suppresses the expression of IL-6 in ischaemic brain tissue during the initial phase of ischaemic stroke, in which the overproduction of IL-6 may aggravate neuronal damage, but not at later time points, when IL-6 promotes neuroprotection and inhibits neuronal death.

Experimental studies suggest that stroke-induced brain damage progresses during subacute stages. Cerebral ischemic injury is associated with the induction of a series of inflammatory events, including the infiltration of circulating immune cells and activation of resident cells. Local brain inflammation is spatiotemporally related to the occurrence of delayed apoptotic cell death. Therefore, ischemia-associated inflammation may not only play a major role in the pathogenesis of neurodegeneration associated with stroke, but may also mediate beneficial effects such as lesion demarcation, wound healing, and tissue regeneration especially via secretion of nerve growth factors. In this context, noninvasive imaging of inflammation associated with ischemic stroke lesions could have a predictive value and may be helpful for the development of cytoprotective drugs.

Assessment of platelet function is a critical component of the treatment and secondary prevention of cerebral infarction, and measurement of platelet-derived microparticle (PDMP) levels using flow cytometry may be a good indicator of platelet function. However, the flow cytometric analysis is not feasible in a variety of clinical situations. The goal of the present study was to measure PDMP levels using an enzyme-linked immunosorbent assay (ELISA) in chronic cerebral infarction patients and to determine the utility of PDMP level measurement for the monitoring of the effect of cilostazol and aspirin. A crossover study was performed using 4-weeks of aspirin (100 mg/day) and 4-weeks of cilostazol (200 mg/day) in 18 patients. PDMP levels were also measured in 20 volunteers as controls. Experiments demonstrated that PDMP levels were significantly higher in chronic cerebral infarction patients (median 8.8 U/ml, interquartile range 5.1-14.9 U/ml, n=18) than in controls (median 5.5 U/ml, interquartile range 5.0-8.2 U/ml, n=20) (P=0.047). PDMP levels did not decrease after therapy with either aspirin (median 10.9 U/ml, interquartile range 6.2-17.9 U/ml, n=12) or cilostazol (median 9.2 U/ml, interquartile range 6.1-14.3 U/ml, n=12) compared with baseline PDMP levels in the 12 patients who completed this trial (median 11.4 U/ml, interquartile range 5.2-23.7 U/ml, n=12). There were no significant differences in PDMP levels between aspirin and cilostazol (P=0.61). In conclusion, PDMP levels as measured by ELISA were increased in patients with chronic cerebral infarction regardless of the anti-platelet therapy. This methodology may be a useful strategy of assessing platelet function in chronic cerebral infarction patients.

Objectives: To investigate the mediator role of inflammation in any relationship between depressive symptoms and ischemic stroke., Design: Longitudinal prospective study., Setting: Review of medical records, death certificates, and the Medicare healthcare utilization database for hospitalizations., Participants: Total of 5,525 elderly men and women aged 65 and older who were prospectively followed from 1989 to 2000 as participants in the Cardiovascular Health Study., Measurements: Depression symptom scores, inflammatory markers., Results: Greater depressive symptoms were associated with risk of ischemic stroke (unadjusted hazard ratio (HR)=1.32, 95% confidence interval (CI)=1.09-1.59; HR=1.26, 95% CI=1.03-1.54, adjusted for traditional risk factors). When a term for inflammation (C-reactive protein (CRP)) was introduced in the model, the HRs were not appreciably altered (unadjusted HR=1.31, 95% CI=1.08-1.58; adjusted HR=1.25, 95% CI=1.02-1.53), indicating that CRP at baseline was not a mediator in this relationship. In analyses stratified according to CRP levels, a J-shaped relationship between depressive symptoms and stroke was evident in the unadjusted analyses; in the fully adjusted model, only CRP in the highest tertile was associated with a higher risk for stroke in the presence of higher depressive symptoms scores., Conclusion: The analyses from this prospective study provide evidence of a positive association between depressive symptoms and risk of incident stroke. Inflammation, as measured according to CRP at baseline, did not appear to mediate the relationship between depressive symptoms and stroke.

Toll-like receptors (TLR) recognize molecular structures associated with pathogens as well as host-derived components and initiate an inflammatory innate immune response. Microglia represent the resident immune host defense and are the major inflammatory cell type in the central nervous system (CNS). We show here that TLR2-deficient mice develop a decreased CNS injury compared to wild type mice in a model of focal cerebral ischemia. TLR2 mRNA is up-regulated in wild type mice during cerebral ischemia. In ischemic brains, TLR2 protein is expressed in lesion-associated microglia. Absence of TLR2 does not affect the recruitment of granulocytes to the infarct region. We conclude that TLR2 in microglia propagates stroke-induced CNS injury.

Toll-like receptors (TLRs) play a critical role in the induction of innate immune responses which have been implicated in neuronal death induced by global cerebral ischemia/reperfusion (GCI/R). The present study investigated the role and mechanisms-of-action of TLR4 signaling in ischemia-induced hippocampal neuronal death. Neuronal damage, activation of the TLR4 signaling pathway, expression of pro-inflammatory cytokines and activation of the PI3K/Akt signaling pathway in the hippocampal formation (HF) were assessed in wild type (WT) mice and TLR4 knockout (TLR4(-/-)) mice after GCI/R. GCI/R increased expression of TLR4 protein in the hippocampal formation (HF) and other brain structures in WT mice. Phosphorylation of the inhibitor of kappa B (p-IkappaB) as well as activation of nuclear factor kappa B (NFkappaB) increased in the HF of WT mice. In contrast, there were lower levels of p-IkappaB and NFkappaB binding activity in TLR4(-/-) mice subjected to GCI/R. Pro-inflammatory cytokine expression was also decreased, while phosphorylation of Akt and GSK3beta were increased in the HF of TLR4(-/-) mice after GCI/R. These changes correlated with decreased neuronal death/apoptosis in TLR4(-/-) mice following GCI/R. These data suggest that activation of TLR4 signaling contributes to ischemia-induced hippocampal neuronal death. In addition, these data suggest that modulation of TLR4 signaling may attenuate ischemic injury in hippocampal neurons.

The damage in ischemic stroke is caused by two events: (i) the ischemic phenomenon by itself; (ii) the self-destructive mechanisms developed as a consequence of ischemia. The inflammatory response is one of these destructive phenomena that accompanies and exacerbates the developing injury. Since it has been suggested that immune cells participate in neuroprotective and restorative processes, modulation rather than elimination of this inflammatory response could be a strategy to improve the neurological outcome. The immune modulator copolymer-1 (Cop-1), a synthetic basic random copolymer of amino acids, is a potent inducer of Th2 regulatory cells which, aside from exerting modulatory actions, is capable of releasing neurotrophic factors. There is evidence that Cop-1-specific T cells exert neuroprotective and even restorative effects in diverse neurodegenerative diseases. In order to test the ability of Cop-1 to prevent ischemic injury in a model of transient middle cerebral artery (MCA) occlusion, two groups of rats were treated either with Cop-1 or with saline solution (SS). Seven days after occlusion, Cop-1 treated rats presented a significant improvement in neurological function compared to SS-treated animals (1.2+/-0.4 and 2.8+/-0.5 mean+/-S.D., respectively; p=0.008). Histological findings showed that the percentage of infarct volume was smaller in Cop-1 treated rats (4.8+/-1.5), in comparison with those receiving SS (32.2+/-8.6; p=0.004). Cop-1 constitutes a promising therapy for stroke; thereby, the enforcement of further experimental investigation is encouraged in order to be able to formulate the best strategy.

Stroke is among the three leading causes of death worldwide and the most frequent cause of permanent disability. Brain ischemia induces an inflammatory response involving activated complement fragments. Here we show that i.v. Ig (IVIG) treatment, which scavenges complement fragments, protects brain cells against the deleterious effects of experimental ischemia and reperfusion (I/R) and prevents I/R-induced mortality in mice. Animals administered IVIG either 30 min before ischemia or after 3 h of reperfusion exhibited a 50-60% reduction of brain infarct size and a 2- to 3-fold improvement of the functional outcome. Even a single low dose of IVIG given after stroke was effective. IVIG was protective in the nonreperfusion model of murine stroke as well and did not exert any peripheral effects. Human IgG as well as intrinsic murine C3 levels were significantly higher in the infarcted brain region compared with the noninjured side, and their physical association was demonstrated by immuno-coprecipitation. C5-deficient mice were significantly protected from I/R injury compared with their wild-type littermates. Exposure of cultured neurons to oxygen/glucose deprivation resulted in increased levels of C3 associated with activation of caspase 3, a marker of apoptosis; both signals were attenuated with IVIG treatment. Our data suggest a major role for complement-mediated cell death in ischemic brain injury and the prospect of using IVIG in relatively low doses as an interventional therapy for stroke.

Cannabinoid CB(2) Receptor (CB(2)) activation has been shown to have immunomodulatory properties without psychotropic effects. The hypothesis of this study is that selective CB(2) agonist treatment can attenuate cerebral ischemia/reperfusion injury. Selective CB(2) agonists (O-3853, O-1966) were administered intravenously 1 h before transient middle cerebral artery occlusion (MCAO) or 10 mins after reperfusion in male mice. Leukocyte/endothelial interactions were evaluated before MCAO, 1 h after MCAO, and 24 h after MCAO via a closed cranial window. Cerebral infarct volume and motor function were determined 24 h after MCAO. Administration of the selective CB(2) agonists significantly decreased cerebral infarction (30%) and improved motor function (P<0.05) after 1 h MCAO followed by 23 h reperfusion in mice. Transient ischemia in untreated animals was associated with a significant increase in leukocyte rolling and adhesion on both venules and arterioles (P<0.05), whereas the enhanced rolling and adhesion were attenuated by both selective CB(2) agonists administered either at 1 h before or after MCAO (P<0.05). CB(2) activation is associated with a reduction in white blood cell rolling and adhesion along cerebral vascular endothelial cells, a reduction in infarct size, and improved motor function after transient focal ischemia.