Elevated HMGB1 and sRAGE levels in cerebrospinal fluid of aneurysmal subarachnoid hemorrhage patients.

BACKGROUND: Neuroinflammation after aneurysmal subarachnoid hemorrhage (aSAH) leads to poor outcome of patients. High mobility group box 1 (HMGB1) contributes to inflammation through binding to receptors for advanced glycation end-products (RAGE) in various diseases. We aimed to determine the production of these two factors after aSAH and their relationship with clinical features. METHODS: HMGB1 and soluble RAGE (sRAGE) levels in cerebrospinal fluid (CSF) of aSAH patients and controls were measured, and their temporal courses were observed. The correlation between early concentrations (days 1-3) and clinical symptoms assessed by disease severity scores, neuroinflammation estimated by CSF IL-6 levels, as well as prognosis evidenced by delayed cerebral ischemia (DCI) and 6-month adverse outcome was investigated. Finally, combined analysis of early levels for predicting prognosis was confirmed. RESULTS: CSF HMGB1 and sRAGE levels were higher in aSAH patients than in controls (P < 0.05), and the levels decreased from higher early to lower over time. Their early concentrations were positively associated with disease severity scores, IL-6 levels, DCI and 6-month poor outcome (P < 0.05). HMGB1 ≥ 6045.5 pg/ml (OR = 14.291, P = 0.046) and sRAGE ≥ 572.0 pg/ml (OR = 13.988, P = 0.043) emerged as independent predictors for DCI, while HMGB1 ≥ 5163.2 pg/ml (OR = 7.483, P = 0.043) and sRAGE ≥ 537.3 pg/ml (OR = 12.653, P = 0.042) were predictors for 6-month poor outcome. Combined analysis of them improved predictive values of adverse prognosis. CONCLUSION: CSF HMGB1 and sRAGE levels of aSAH patients were increased early and then varied dynamically, which might act as potential biomarkers for poor outcome, especially when co-analyzed.

Aerobic Glycolysis Induced by mTOR/HIF-1α Promotes Early Brain Injury After Subarachnoid Hemorrhage via Activating M1 Microglia.

M1 microglial activation is crucial for the pathogenesis of early brain injury (EBI) following subarachnoid hemorrhage (SAH), and there is growing evidence that glucose metabolism is frequently involved in microglial activation. However, the molecular mechanism of glycolysis and its role in M1 microglial activation in the context of EBI are not yet fully understood. In this study, firstly, the relationship between aerobic glycolysis and M1 microglial activation as well as SAH-induced EBI was researched in vivo. Then, intervention on mammalian target of rapamycin (mTOR) was performed to investigate the effects on glycolysis-dependent M1 microglial activation and EBI and its relationship with hypoxia-inducible factor-1α (HIF-1α) in vivo. Next, Hif-1α was inhibited to analyze its role in aerobic glycolysis, M1 microglial activation, and EBI in vivo. Lastly, both in vivo and in vitro, mTOR inhibition and Hif-1α enhancement were administered simultaneously, and the combined effects were further confirmed again. The results showed that aerobic glycolysis and M1 microglial polarization were increased after SAH, and glycolytic inhibition could attenuate M1 microglial activation and EBI. Inhibition of mTOR reduced glycolysis-dependent M1 microglial polarization and EBI severity by down-regulating HIF-1α expression, while enhancement had the opposite effects. Blockading HIF-1α had the similar effects as suppressing mTOR, while HIF-1α agonist worked against mTOR antagonist when administered simultaneously. In conclusion, the present study showed new evidence that aerobic glycolysis induced by mTOR/HIF-1α might promote EBI after SAH by activating M1 microglia. This finding provided new insights for the treatment of EBI.

Role of TREM-1 in the development of early brain injury after subarachnoid hemorrhage.

Triggering receptor expressed on myeloid cells-1 (TREM-1) was found to be induced in the context of subarachnoid hemorrhage (SAH) before. This study further investigates its role in the development of SAH-induced early brain injury (EBI). Firstly, rats were randomly divided into Sham and SAH groups for analysis of temporal patterns and cellular localization of TREM-1. Secondly, TREM-1 intervention was administrated to produce Sham, vehicle, antagonist and agonist groups, for analyzing TREM-1, Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and NF-κB expressions at 24 h post-modeling, and EBI assessment at 24 h and 72 h. Thirdly, TLR4 inhibitor (TAK-242) was exploited to produce Sham, Sham+TAK-242, SAH, and SAH + TAK-242 groups to analyze the effects of TLR4 inhibition on TREM-1 induction and EBI evaluation at 72 h. Fourthly, the relationship of soluble TREM-1 (sTREM-1) levels in cerebrospinal fluid of SAH patients with Hunt-Hess grades were explored. The results showed that TREM-1 increased in the brain after experimental SAH (eSAH) early at 6 h and peaked at 48 h, which was found to be located in microglia and endothelial cells. TREM-1 inhibition attenuated EBI associated with TLR4/MyD88/NF-κB suppression, while enhancement had the opposite effects. Contrarily, TLR4 inhibition prevented TREM-1 induction and ameliorated EBI. In addition, sTREM-1 levels in SAH patients positively correlated with Hunt-Hess grades. Overall, the present study provides new evidence that TREM-1 increases dynamically in the brain after eSAH and it is located in microglia and endothelial cells, which may aggravate EBI by interacting with TLR4 pathway. And sTREM-1 in patients might act as a monitoring biomarker of EBI, providing new insights for future studies.

Inhibition of TREM-1 attenuates early brain injury after subarachnoid hemorrhage via downregulation of p38MAPK/MMP-9 and preservation of ZO-1.

Early brain injury (EBI) mainly leads to the poor outcome of subarachnoid hemorrhage (SAH), with which inflammation is closely associated. It was reported that triggering receptor expressed on myeloid cells-1 (TREM-1), a critical inflammatory amplifier, increased in cerebrospinal fluid of SAH patients in our recent research. This study was conducted to examine the effects of TREM-1 inhibition on EBI after experimental SAH (eSAH). The endovascular perforation model of SAH was produced and 120 rats were randomly divided into four groups as sham, SAH + vehicle and SAH + LP17 (1.0 mg/kg and 3.5 mg/kg). The LP17, a selective inhibitor of TREM-1, or vehicle was administered by an intraperitoneal injection 1 h post-modeling. Western blot analysis for TREM-1, p38 mitogen-activated protein kinase (p38MAPK), matrix metalloproteinase-9 (MMP-9) and zonula occludens-1 (ZO-1) was conducted at 24 h post-modeling. EBI was assessed in terms of mortality, neuroscore, brain edema, blood-brain barrier (BBB) disruption in 24 and 72 h. The results showed that TREM-1 was induced in brain after eSAH. Both high dose (3.5 mg/kg) and low dose (1.0 mg/kg) of Lp17 significantly inhibited the induction of TREM-1, but only high dose of LP17 improved neuroscore, brain edema, and BBB disruption which are associated with downregulation of p38MAPK/MMP-9 and subsequent preservation of ZO-1. Overall, the current study provides new evidence that TREM-1 may participate in the pathogenesis of SAH-induced EBI via promoting p38MAPK/MMP-9 activation and ZO-1 degradation, while TREM-1 inhibition attenuated the EBI severity obviously, providing a novel approach for the treatment of EBI.

PPAR-γ Promotes Hematoma Clearance through Haptoglobin-Hemoglobin-CD163 in a Rat Model of Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: PPAR-γ is a transcriptional factor which is associated with promoting hematoma clearance and reducing neurological dysfunction after intracerebral hemorrhage (ICH). Haptoglobin- (Hp-) hemoglobin- (Hb-) CD163 acts as a main pathway to Hb scavenging after ICH. The effect of PPAR-γ on the Hp-Hb-CD163 signaling pathway has not been reported. We hypothesized that PPAR-γ might protect against ICH-induced neuronal injury via activating the Hp-Hb-CD163 pathway in a rat ICH model. METHODS: 107 Sprague-Dawley rats were used in this research. They were randomly allocated to 4 groups as follows: sham group, vehicle group, monascin-treated group, and Glivec-treated group. Animals were euthanized at 3 days after the model was established successfully. We observed the effects of PPAR-γ on the brain water content, hemoglobin levels, and the expressions of CD163 and Hp in Western blot and real-ime PCR; meanwhile, we measured hematoma volumes and edema areas by MRI scanning. RESULT: The results showed that PPAR-γ agonist significantly reduced hematoma volume, brain edema, and hemoglobin after ICH. It also enhanced CD163 and Hp expression while PPAR-γ antagonist had the opposite effects. CONCLUSIONS: PPAR-γ promotes hematoma clearance and plays a protective role through the Hp-Hb-CD163 pathway in a rat collagenase infusion ICH model.

Haematoma scavenging in intracerebral haemorrhage: from mechanisms to the clinic.

The products of erythrocyte lyses, haemoglobin (Hb) and haem, are recognized as neurotoxins and the main contributors to delayed cerebral oedema and tissue damage after intracerebral haemorrhage (ICH). Finding a means to efficiently promote absorption of the haemolytic products (Hb and haem) around the bleeding area in the brain through stimulating the function of the body's own garbage cleaning system is a novel clinical challenge and critical for functional recovery after ICH. In this review, available information of the brain injury mechanisms underlying ICH and endogenous haematoma scavenging system is provided. Meanwhile, potential intervention strategies are discussed. Intracerebral blood itself has 'toxic' effects beyond its volume effect after ICH. Haptoglobin-Hb-CD163 as well as haemopexin-haem-LRP1 is believed to be the most important endogenous scavenging pathway which participates in blood components resolution following ICH. PPARγ-Nrf2 activates the aforementioned clearance pathway and then accelerates haematoma clearance. Meanwhile, the scavenger receptors as novel targets for therapeutic interventions to treat ICH are also highlighted.

The effect of monascin on hematoma clearance and edema after intracerebral hemorrhage in rats.

BACKGROUND AND PURPOSE: Intracerebral hemorrhage (ICH) is a particularly devastating form of stroke with high mortality and morbidity. Hematomas are the primary cause of neurologic deficits associated with ICH. The products of hematoma are recognized as neurotoxins and the main contributors to edema formation and tissue damage after ICH. Finding a means to efficiently promote absorption of hematoma is a novel clinical challenge for ICH. Peroxisome proliferator-activated receptor gamma (PPARγ) and nuclear factor erythroid 2-related factor 2 (Nrf2), had been shown that, can take potential roles in the endogenous hematoma clearance. However, monascin, a novel natural Nrf2 activator with PPARγ agonist, has not been reported to play a role in ICH. This study was designed to evaluate the effect of monascin on neurological deficits, hematoma clearance and edema extinction in a model of ICH in rats. METHODS: 164 adult male Sprague-Dawley (SD) rats were randomly divided into sham; vehicle; monascin groups with low dosages (1mg/kg/day), middle dosages (5mg/kg/day) and high dosages (10mg/kg/day) respectively. Animals were euthanized at 1, 3 and 7days following neurological evaluation after surgery. We examined the effect of monascin on the brain water contents, blood brain barrier (BBB) permeability and hemoglobin levels, meanwhile reassessed the volume of hematoma and edema around the hematoma by Magnetic Resonance Imaging (MRI) in each group. RESULTS: The high dosage of monascin significantly improved neurological deficits, reduced the volume of hematoma in 1-7days after ICH, decreased BBB permeability and edema formation in 1-3days following ICH. CONCLUSION: Our study demonstrated that the high dosage of monascin played a neuroprotective role in ICH through reducing BBB permeability, edema and hematoma volume.

Early elevated levels of soluble triggering receptor expressed on myeloid cells-1 in subarachnoid hemorrhage patients.

Early brain injury (EBI) contributes to poor prognosis of subarachnoid hemorrhage (SAH). This study aimed to clarify whether triggering receptor expressed on myeloid cells-1 (TREM-1) was implicated in the inflammatory mechanisms of EBI. The cerebrospinal fluid (CSF) levels of soluble TREM-1 (sTREM-1), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) as well as plasma levels of white blood cells (WBC) count and C-reactive protein in 17 SAH patients at early stage (within the EBI period) and 9 volunteers were observed. Also World Federation of Neurosurgical Societies (WFNS) scale of SAH patients was calculated on admission. Compared to controls, increased CSF levels of sTREM-1 (t = 5.66, P < 0.001), TNF-α (t = 5.41, P < 0.001) and IL-6 (t = 2.98, P = 0.007) as well as elevated plasma WBC counts (t = 7.61, P < 0.001) and C-reactive protein levels (t = 3.91, P = 0.001) were found in SAH patients. Considering the increased WBC counts in SAH group, covariate analysis was also performed when comparing patients' sTREM-1 levels with respect to controls and no obvious difference was found (F = 0.982, P = 0.332). For SAH group, early CSF concentrations of sTREM-1 were correlated with those of both TNF-α (r = 0.582, P = 0.014) and IL-6 (r = 0.593, P = 0.012). Also the CSF sTREM-1 levels were positively correlated with WBC counts (r = 0.629, P = 0.007) and C-reactive protein levels (r = 0.804, P < 0.001) as well as WFNS scale (r = 0.835, P < 0.001). This study showed an early increased sTREM-1 CSF level in SAH patients, which correlated with inflammation intensity post-SAH and clinical severity, indicating that TREM-1 may participate in the inflammatory mechanisms of EBI.

Increased levels of soluble triggering receptor expressed on myeloid cells-1 in cerebrospinal fluid of subarachnoid hemorrhage patients.

Triggering receptor expressed on myeloid cells-1 (TREM-1) has been highlighted as a key amplifier of inflammatory response in various diseases. To determine the contribution of TREM-1 in the inflammatory cascade after subarachnoid hemorrhage (SAH), concentrations of soluble TREM-1 (sTREM-1) in cerebrospinal fluid (CSF) from 30 SAH patients and 9 healthy volunteers were measured by enzyme-linked immunosorbent assay. It was shown that the CSF sTREM-1 levels of SAH patients increased significantly than that of the volunteers (P<0.05). Interestingly, the levels were up-regulated dynamically over time with an early increase within 2days and a late peak at day 6 after SAH onset. In addition, it was found that the early sTREM-1 levels (within 3days post-SAH) were negatively correlated with Glasgow Coma Scale (r=-0.550, P=0.022) and positively correlated with the Hunt and Hess scale (r=0.603, P=0.010) respectively conducted on admission, also the early sTREM-1 levels were negatively correlated with Glasgow Outcome Scale (r=-0.505, P=0.039) and positively correlated with modified Rankin Scale (r=0.557, P=0.020) respectively conducted one month after SAH. Altogether, this is the first study showing CSF sTREM-1 dynamics in SAH patients, and exploring the correlations of early CSF sTREM-1 levels to patients' severity and prognosis, which suggests that TREM-1 may play an important role in the inflammatory cascade after SAH and act as a monitoring biomarker facilitated to assess the severity and prognosis of SAH patients.

Effect Comparison of Both Iron Chelators on Outcomes, Iron Deposit, and Iron Transporters After Intracerebral Hemorrhage in Rats.

Iron overload plays a key role in brain injury after intracerebral hemorrhage (ICH). We explored the roles of ferric iron chelator-deferiprone (DFP)-and ferrous iron chelator-clioquinol (CQ)-in ICH rats through the outcomes, iron deposits, reactive oxygen species (ROS), brain water content, and related iron transporters. One hundred eight Sprague-Dawley rats received intra-striatal infusions of 0.5 U of type IV collagenase to establish ICH models. The rats were randomly assigned to the sham, vehicle, DFP, and CQ groups. We evaluated the outcomes, iron levels, brain water content, and ROS; meanwhile, immunohistochemistry and real-time quantitative polymerase chain reaction (RT-qPCR) were utilized to determine ferritin, transferrin, transferrin receptor, divalent metal transport 1 (DMT1), and ferroportin at 48 and 72 h, 7 and 14 days after surgery. Our results showed ICH induced iron overload, brain edema, ROS formation, and neurological deficits. Both iron chelators decreased iron levels; CQ improved the neurological outcome, attenuated brain edema, and ROS production. DFP reduced iron contents but not brain water content and ROS generation. DFP failed to improve the outcome. ICH initiated endogenous iron chelators and transporters, both exogenous iron chelators enhanced expression of transferrin and transferrin receptor. CQ enhanced expression of ferroportin but not DMT1, while DFP enhanced expression of DMT1 but not ferroportin. Ferrous iron contributed to brain injury, and binding ferrous iron can modestly improve outcome after ICH in rats. The exogenous ferrous iron chelator possibly functioned via endogenous ferrous iron transporters on ICH. Therefore, ferrous iron may be a promising target for ICH in future.

Incidence and survival of lacunar infarction in a southern Chinese population: A 7-year prospective study.

OBJECTIVE: Little attention has been paid to the epidemiological characteristics of lacunar infarction (LAC) in China before. This study aimed to examine the incidence and survival of LAC in a southern Chinese population. METHODS: From 2004-2010 in Changsha, two communities with a registered population of ∼100 000 were selected and data from first-ever ischaemic stroke (IS) cases were prospectively collected. Then the epidemiological characteristics of LAC and non-LAC were evaluated. RESULTS: During the study period, the age-standardized incidence increased at an annual rate of 0.7% (p < 0.001) for LAC and 2.0% (p < 0.001) for non-LAC. The mean annual age-standardized incidence of LAC and non-LAC was 28.2/100 000 and 45.0/100 000, respectively. Compared with non-LAC patients, the prevalence of hypertension, diabetes and hyperlipidemia was significantly higher in patients with LAC (p < 0.05). Although the 30-day fatality rate was significantly lower in patients with LAC than non-LAC (0.5% vs. 14.9%, p < 0.001), there was no significant difference in survival between the two groups (96.7% vs. 95.2%, p = 0.203) after excluding the patients who died within 1 year of stroke onset. CONCLUSION: LAC is a common stroke sub-type in southern China and the long-term prognosis is not benign.

Incidence and trends of stroke and its subtypes in Changsha, China from 2005 to 2011.

During the 1990s no significant changes were found for the high incidence of ischemic stroke (IS) in Changsha, in contrast to the increase observed in Beijing and Shanghai. However, the epidemiological patterns of stroke may change with economic development. This study aimed to examine the characteristics of stroke incidence transition in Changsha from 2005 to 2011. In 2007 two communities with a registered population of about 100,000 were selected and data from stroke patients who presented between 2005 and 2007 were retrospectively collected from January to June 2008. From January to December 2007 a stroke surveillance network was established and stroke patients who presented between 2008 and 2011 were prospectively registered. From 2005 to 2011 the mean annual age-adjusted incidence of first-ever stroke was 168.5/100,000 (95% confidence interval [CI] 159.0-178.0/100,000), with 189.3/100,000 (95% CI 175.1-178.0/100,000) for men and 148.7/100,000 (95% CI 136.0-161.4/100,000) for women. The mean annual age-adjusted incidence of IS, intracranial hemorrhage and subarachnoid hemorrhage was 72.6/100,000 (95% CI 66.3-78.9/100,000), 85.1/100,000 (95% CI 78.3-91.9/100,000) and 9.4/100,000 (95% CI 7.1-11.7/100,000), respectively. During the study period, the age-adjusted incidence of stroke increased at an annual rate of 3.7% (p=0.001); at 4.2% for men (p=0.001) and 3.1% for women (p=0.026). The age-adjusted incidence of IS increased at an annual rate of 3.5% (p=0.003) but no significant changes were seen for hemorrhagic stroke. Characteristics of stroke incidence transition may reflect underlying changes in risk factors and there is an urgent need to identify these factors and launch appropriate public health campaigns.

Public and professional education on urgent therapy for acute ischemic stroke: a community-based intervention in Changsha.

Excessive delay of presentation for stroke in China is reported. In this study, an intervention trial was conducted to promote urgent therapy for acute ischemic stroke. Two communities in Changsha were selected as either intervention or control community from November 2007 to December 2011. Public and professional education was regularly implemented in the intervention community. Publics' knowledge about early identification and urgent therapy of ischemic stroke was surveyed before and after intervention in the two communities. During the intervention period, first-ever ischemic stroke cases occurring in the intervention community (intervention group) and that in the control community (control group) were collected and followed for 90 days. After intervention, the publics' knowledge levels in the intervention community improved significantly. Intervention group' average presentation time was shorter than control group (8.3 ± 5.8 vs. 10.5 ± 6.5 h, P = 0.018). Percentage of presentation time within 3 h (48.0 %), the rate of ambulance use (59.0 %), and thrombolytic therapy (9.3 %) in the intervention group was all obviously higher than that in the control group (21.5, 41.3, and 4.5, respectively). When admitted, the intervention group had lower mean systolic blood pressure (160.8 ± 26.7 vs. 164.7 ± 26.8 mmHg, P = 0.000) than control group. Survivors in the intervention group were more likely to be in higher Barthel index scoring groups than that in the control group at day 90 [(75, 50-100) vs. (65, 35-90), P = 0.035]. Public and professional education may promote prompt presentation and urgent therapy for ischemic stroke, which may be helpful for patients' prognosis.

Myasthenia gravis appearing after thymectomy.

We aimed to evaluate the clinical characteristics of patients with postoperative myasthenia gravis (MG). We retrospectively studied the data of 174 thymoma patients treated between 1990 and 2008 in Xiangya Hospital. Six of 125 patients without preoperative MG (4.8%) developed postoperative MG. The anti-acetylcholine-receptor binding antibody (ARAb) titers were elevated preoperatively in 22 of the 125 patients (17.6%) who did not have preoperative MG (range, 0.5-67.6nmol/L). Four of six patients with postoperative MG had positive ARAb levels preoperatively. Serum titers were exacerbated in all six patients at the onset of postoperative MG. Postoperative MG was responsive to anti-cholinesterase compounds and/or steroids. We concluded that a thymectomy did not prevent postoperative MG. Exacerbated ARAb levels after thymectomy suggested an extrathymic production of ARAb. We suggest that a rise in the ARAb titer might be a risk indictor for post-thymectomy MG.