Intracerebral haemorrhage: mechanisms of injury and therapeutic targets

Taurine supplementation reduces neuroinflammation and protects against white matter injury after intracerebral hemorrhage in rats

Intracerebral hemorrhage (ICH) initiates a neuroinflammatory cascade that contributes to substantial neuronal damage and neurological deterioration. Taurine, an abundant amino acid in the nervous system, is reported to reduce inflammatory injury in various central nervous system diseases, but its role and the possible underlying mechanisms in the pathology following ICH remains unclear. This study was designed to evaluate the effect of taurine supplementation on neurological deficits, acute inflammatory responses and white matter injury in a model of ICH in rats. Adult male Sprague-Dawley (SD) rats subjected to collagenase-induced ICH injury were injected intravenously with different concentrations of taurine or vehicle 10 min after ICH and subsequently daily for 3 days. Behavioral studies, brain water content, and assessments of hemorrhagic lesion volume were quantified at day 1 and day 3 post-ICH. Neuronal damage, peri-hematomal inflammatory responses, and white matter injury were determined at 24 h, meanwhile, the content of hydrogen sulfide (H₂S) along with the expression of cystathionine-β-synthase (CBS) and P2X7 receptor (P2X7R) in peri-hematomal tissues was analyzed to investigate the possible anti-inflammatory mechanism of taurine. Treatment with a high dosage of taurine (50 mg/kg) significantly attenuated functional deficits and reduced brain edema and hemorrhagic lesion volume after ICH. Taurine administration also resulted in significant amelioration of neuronal damage and white matter injury. These changes were associated with marked reductions in neutrophil infiltration, glial activation, and expression levels of inflammatory mediators. Moreover, the anti-inflammatory effect of taurine was accompanied by increased H₂S content, enhanced CBS expression, and less expression of P2X7R. Our study demonstrated that the high dosage of taurine supplementation effectively mitigated the severity of pathological inflammation and white matter injury after ICH, and the mechanism may be related to upregulation of H₂S content and reduced P2X7R expression.

Cofilin signaling in hemin-induced microglial activation and inflammation

Intracerebral hemorrhage (ICH) is the most severe form of stroke and is further exacerbated by the secondary injury involving inflammatory response due to the activation of microglia. This secondary injury is partly due to the toxic effects of hemin, an endogenous breakdown product of hemoglobin. Cofilin, an actin depolymerizing factor, controls actin dynamics and has been previously shown to be involved in mediating neuronal cell death in ischemic conditions and during bacterial lipopolysaccharide induced microglial activation. There are limited studies regarding the deleterious effects of extremely high concentrations of hemin released during ICH and its effects on microglia and subsequent cofilin response. Therefore, investigations were conducted to study the effects of hemin on microglial activation induced inflammation and the critical role of cofilin in mediating the response. We observed that hemin treated microglia had a concentration dependent increase in cofilin expression and NO production. There were increased levels of iNOS, TNF-α, HO1, Nrf2, Wfs-1, XBP-1 and spliced XBP-1 observed in response to hemin treatment and the signaling was found to be partly mediated by cofilin. Acute hemin treatment did not evoke Ca2+ signaling and long-term treatment of hemin also resulted in the failure of microglial response to acetylcholine-evoked Ca2+ signaling. Knockdown of cofilin by siRNA also reduced acetylcholine-evoked Ca2+ signaling. These studies demonstrate that cofilin signaling is important in hemin-induced inflammation, oxidative stress, ER stress, microglial migration, and the ability to evoke Ca2+ signaling. Therefore, cofilin inhibition could be a potential therapy in brain injuries triggered by hemin toxicity in conditions like ICH.

Selective NLRP3 (Pyrin Domain-Containing Protein 3) Inflammasome Inhibitor Reduces Brain Injury After Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Intracerebral hemorrhage (ICH) is a devastating disease without effective treatment. As a key component of the innate immune system, the NOD-like receptor (NLR) family, NLRP3 (pyrin domain-containing protein 3) inflammasome, when activated after ICH, promotes neuroinflammation and brain edema. MCC950 is a potent, selective, small-molecule NLRP3 inhibitor that blocks NLRP3 activation at nanomolar concentrations. Here, we examined the effect of MCC950 on brain injury and inflammation in 2 models of ICH in mice.

METHODS

In mice with ICH induced by injection of autologous blood or bacterial collagenase, we determined the therapeutic potential of MCC950 and its mechanisms of neuroprotection.

RESULTS

MCC950 reduced IL-1β (interleukin-1β) production and attenuated neurodeficits and perihematomal brain edema after ICH induction by injection of either autologous blood or collagenase. In mice with autologous blood-induced ICH, the protection of MCC950 was associated with reduced leukocyte infiltration into the brain and microglial production of IL-6. MCC950 improved blood-brain barrier integrity and diminished cell death. Notably, the protective effect of MCC950 was abolished in mice depleted of either microglia or Gr-1⁺ myeloid cells.

CONCLUSIONS

These results indicate that the NLRP3 inflammasome inhibitor, MCC950, attenuates brain injury and inflammation after ICH. Hence, NLRP3 inflammasome inhibition is a potential therapy for ICH that warrants further investigation.

Rosiglitazone Infusion Therapy Following Minimally Invasive Surgery for Intracranial Hemorrhage Evacuation Decreased Perihematomal Glutamate Content and Blood-Brain Barrier Permeability in Rabbits

OBJECTIVE

To observe effects of rosiglitazone (RSG) infusion therapy on perihematomal peroxisome-proliferator-activated receptor gamma (PPARγ), glutamate, blood-brain barrier (BBB) permeability, and brain edema.

METHODS

Fifty male rabbits (2.8-3.4 kg) were randomly assigned to a normal control (NC) group, model control (MC) group, RSG group, minimally invasive surgery (MIS) group, or MIS and RSG (MIS+RSG) group. Intracranial hemorrhage was induced in all rabbits except for the NC group. MIS procedures were performed to evacuate the intracranial hemorrhage 6 hours after the intracranial hemorrhage model was prepared successfully. The animals were sacrificed on day 7, and the perihematomal brain tissue was obtained to determine PPARγ, glutamate, and BBB permeability.

RESULTS

Compared with the MC group, the MIS group displayed a remarkable decrease in PPARγ, glutamate, and BBB permeability. The RSG group showed similar results in glutamate level and BBB permeability but a significant increase in PPARγ. The MIS+RSG group displayed an increase in PPARγ and a more significant decrease in glutamate, BBB permeability, and neurologicl deficit scores compared with the other groups.

CONCLUSIONS

Performing MIS followed by RSG infusion therapy might increase PPARγ expression and might be more efficacious for reducing glutamate level and BBB permeability and improving neurologic function than MIS or RSG therapy used alone.

Challenges for intraventricular hemorrhage research and emerging therapeutic targets

INTRODUCTION

Intraventricular hemorrhage (IVH) affects both premature infants and adults. In both demographics, it has high mortality and morbidity. There is no FDA approved therapy that improves neurological outcome in either population highlighting the need for additional focus on therapeutic targets and treatments emerging from preclinical studies. Areas covered: IVH induces both initial injury linked to the physical effects of the blood (mass effect) and secondary injury linked to the brain response to the hemorrhage. Preclinical studies have identified multiple secondary injury mechanisms following IVH, and particularly the role of blood components (e.g. hemoglobin, iron, thrombin). This review, with an emphasis on pre-clinical IVH research, highlights therapeutic targets and treatments that may be of use in prevention, acute care, or repair of damage. Expert opinion: An IVH is a potentially devastating event. Progress has been made in elucidating injury mechanisms, but this has still to translate to the clinic. Some pathways involved in injury also have beneficial effects (coagulation cascade/inflammation). A greater understanding of the downstream pathways involved in those pathways may allow therapeutic development. Iron chelation (deferoxamine) is in clinical trial for intracerebral hemorrhage and preclinical data suggest it may be a potential treatment for IVH.

Surgical Outcome in Patients with Spontaneous Supratentorial Intracerebral Hemorrhage

The aim of the paper was to evaluate the surgical outcome in patients with spontaneous supratentorial intracerebral hemorrhage (ICH) after surgical intervention, in respect to the initial clinical conditions, age, sex, hemispheric side and anatomic localization of ICH. Thirty-eight surgically treated patients with spontaneous supratentorial intracerebral hemorrhage were included in the study. The surgical outcome was evaluated three months after the initial admission, according to the Glasgow Outcome Scale (GOS). The surgical treatment was successful in 14 patients (37%), whereas it was unsuccessful in 24 patients (63%). We have detected a significant negative correlation between the Glasgow Coma Scale (GCS) scores on admission and the GOS scores after three months, suggesting worse neurological outcome in patients with initially lower GCS scores. The surgical outcome in patients with ICH was not affected by the sex, the hemispheric side and the anatomic localization of ICH, but the age of the patients was estimated as a significant factor for their functional outcome, with younger patients being more likely to be treated successfully. The surgical outcome is affected from the initial clinical state of the patients and their age. The treatment of ICH is still an unsolved clinical problem and the development of new surgical techniques with larger efficiency in the evacuation of the hematoma is necessary, thus making a minimal damage to the normal brain tissue, as well as decreasing the possibility of postoperative bleeding.

Rehabilitation following hemorrhagic stroke: building the case for stroke-subtype specific recovery therapies

Intracerebral hemorrhage (ICH), a form of brain bleeding and minor subtype of stroke, leads to significant mortality and long-term disability. There are currently no validated approaches to promote functional recovery after ICH. Research in stroke recovery and rehabilitation has largely focused on ischemic stroke, but given the stark differences in the pathophysiology between ischemic and hemorrhagic stroke, it is possible that strategies to rehabilitate the brain in distinct stroke subtypes will be different. Here, we review our current understanding of recovery after primary intracerebral hemorrhage with the intent to provide a framework to promote novel, stroke-subtype specific approaches.

Perihematomal Edema Expansion Rates and Patient Outcomes in Deep and Lobar Intracerebral Hemorrhage

BACKGROUND

Perihematomal edema (PHE) expansion rate may predict functional outcome following spontaneous intracerebral hemorrhage (ICH). We hypothesized that the effect of PHE expansion rate on outcome is greater for deep versus lobar ICH.

METHODS

Subjects (n = 115) were retrospectively identified from a prospective ICH cohort enrolled from 2000 to 2013. Inclusion criteria were age ≥ 18 years, spontaneous supratentorial ICH, and known onset time. Exclusion criteria were primary intraventricular hemorrhage (IVH), trauma, subsequent surgery, or warfarin-related ICH. ICH and PHE volumes were measured from CT scans and used to calculate expansion rates. Logistic regression assessed the association between PHE expansion rates and 90-day mortality or poor functional outcome (modified Rankin Scale > 2). Odds ratios are per 0.04 mL/h.

RESULTS

PHE expansion rate from baseline to 24 h (PHE24) was associated with mortality for deep (p = 0.03, OR 1.13[1.02-1.26]) and lobar ICH (p = 0.02, OR 1.03[1.00-1.06]) in unadjusted regression and in models adjusted for age (deep p = 0.02, OR 1.15[1.02-1.28]; lobar p = 0.03, OR 1.03[1.00-1.06]), Glasgow Coma Scale (deep p = 0.03, OR 1.13[1.01-1.27]; lobar p = 0.02, OR 1.03[1.01-1.06]), or time to baseline CT (deep p = 0.046, OR 1.12[1.00-1.25]; lobar p = 0.047, OR 1.03[1.00-1.06]). PHE expansion rate from baseline to 72 h (PHE72) was associated with mRS > 2 for deep ICH in models that were unadjusted (p = 0.02, OR 4.04[1.25-13.04]) or adjusted for ICH volume (p = 0.02, OR 4.3[1.25-14.98]), age (p = 0.03, OR 5.4[1.21-24.11]), GCS (p = 0.02, OR 4.19[1.2-14.55]), or time to first CT (p = 0.03, OR 4.02[1.19-13.56]).

CONCLUSIONS

PHE72 was associated with poor functional outcomes after deep ICH, whereas PHE24 was associated with mortality for deep and lobar ICH.

Hemoglobin pretreatment endows rat cortical astrocytes resistance to hemin-induced toxicity via Nrf2/HO-1 pathway

Oxidative stress mediated secondary injury contributes to neurological deterioration after intracerebral hemorrhage (ICH). Astrocytes, the most dominant cells in the central nervous system (CNS), play key roles in maintaining redox homeostasis by providing oxidative stress defense. Hemoglobin (Hb), the primary component released by hemolysis, is an effective activator of astrocytes. Hemin, the product of Hb degradation, is highly toxic due to the induction of reactive oxygen species (ROS). We speculate that Hb-activated astrocytes are resistant to hemin-induced toxicity. To verify our speculation, Hb-pretreated astrocytes were exposed to hemin, intracellular ROS accumulation and cell apoptosis were evaluated. Heme oxygenase 1 (HO-1) and nuclear transcription factor-erythroid 2 related factor (Nrf2) expression were observed to explore the potential mechanism. The results demonstrated that Hb induced upregulation and nuclear translocation of Nrf2 in astrocytes, resulted in HO-1 upregulation, which contributed to reduced ROS accumulation and apoptosis rate. Knocking down Nrf2 expression by siRNA suppressed Hb-induced upregulation of HO-1 expression and increased the susceptibility of Hb-pretreated astrocytes to hemin-induced toxicity. Taken together, Hb-activated astrocytes acquired resistance to hemin-induced toxicity via Nrf2/HO-1 pathway. This phenomenon can be considered as the adaptive self-defense in the pathological process of ICH. Hb pre-warned astrocytes and enhanced their capability of handling the coming hemin "flood". Nrf2/HO-1 may be employed as a target for neuroprotection after ICH.

Soluble CD163 in intracerebral hemorrhage: biomarker for perihematomal edema

Objective

Patients with intracerebral hemorrhage (ICH) may elaborate varying degrees of perihematomal edema (PHE), requiring closer monitoring and a higher intensity of treatment. Here, we explore whether the soluble form of CD163, a scavenger receptor responsible for hemoglobin sequestration, can serve as a prognostic biomarker of PHE development and poor outcome after ICH.

Methods

Our study cohort was comprised of 51 primary age- and sex-matched ICH patients with moderate-sized, hypertensive deep hemorrhages. Patients were part of a prospective ICH registry cataloguing admission data along with functional outcomes. We measured sCD163 levels in serial serum and cerebrospinal fluid (CSF) samples obtained at prespecified timepoints. Descriptive statistics, including a generalized estimating equation for longitudinal data, were used to analyze sCD163 in relation to ICH outcomes.

Results

Acute serum sCD163 (<48 h postictus) was significantly elevated in ICH patients compared to both acute neurological event controls (P = <0.001) and healthy controls (P = 0.003). As predicted, acute serum sCD163 levels were significantly associated with both hematoma volume expansion (P = 0.009) and PHE expansion (P = 0.002). Further examination determined that patients with high PHE expansion had poorer modified Rankin Scale scores at discharge (P = 0.024), and circulating sCD163 levels were found to be significantly lower in patients with high-level PHE expansion.

Interpretation

Acute sCD163 levels may be a useful biomarker for the acute identification of patients at risk for hematoma expansion, perihematomal edema expansion and poorer short-term outcomes.

Prognostic Significance of Ultraearly Hematoma Growth in Spontaneous Intracerebral Hemorrhage Patients Receiving Hematoma Evacuation

OBJECTIVE

To investigate the association between ultraearly hematoma growth (uHG) and clinical outcome in patients with spontaneous intracerebral hemorrhage (sICH) receiving hematoma evacuation.

METHODS

Supratentorial sICH patients receiving hematoma evacuation within 24 hours after ictus were enrolled in this study. uHG was defined as baseline hematoma volume/onset-to-computed tomography (CT) time (mL/h). The outcome was assessed by the modified Rankin Scale (mRS) score at 3 months. Unfavorable outcome was defined as mRS >2.

RESULTS

A total of 93 patients were enrolled in this study. The mean uHG was 10.3 ± 5.5 mL/h. In 69 (74.2%) of patients, the outcome was unfavorable at 3 months. The uHG in patients with unfavorable outcome were significantly higher than in those with favorable outcome (11.0 ± 6.1 mL/h vs. 8.3 ± 2.5 mL/h, P = 0.003). The optimal cutoff of uHG for predicting unfavorable outcome was 8.7 mL/h. The sensitivity, specificity, positive predictive value, and negative predictive value of uHG >8.7 mL/h for predicting unfavorable outcome were 56.5%, 75.0%, 86.7%, and 37.5%, respectively.

CONCLUSIONS

uHG is a helpful predictor of unfavorable outcome in sICH patients treated with hematoma evacuation. The optimal cutoff of uHG to assist in predicting unfavorable outcome in sICH patients receiving hematoma evacuation is 8.7mL/h.

Simvastatin accelerates hematoma resolution after intracerebral hemorrhage in a PPARγ-dependent manner

To date, the neuroprotective effects of statins on intracerebral hemorrhage (ICH) are not well established. This study explored the effect and potential mechanism of simvastatin treatment on ICH. In the present study, the effects of simvastatin on hematoma absorption, neurological outcome, CD36 expression and microglia polarization were examined in rat model of ICH model. In the meantime, inhibitory effect of PPARγ inhibitor GW9662 was investigated following ICH. Additionally, the effect of simvastatin on PPARγ activation was also investigated in rat ICH model and primary microglia culture. Much more, the role of PPARγ and CD36 in simvastatin-mediated erythrocyte phagocytosis was also detected by using in vivo or in vitro phagocytosis models, respectively. After ICH, simvastatin promoted hematoma absorption and improved neurological outcome after ICH while upregulating CD36 expression and facilitating M2 phenotype polarization in perihematomal microglia. In addition, simvastatin increased PPARγ activation and reinforced microglia-induced erythrocyte phagocytosis in vivo and in vitro. All above effects of simvastatin were abolished by PPARγ inhibitor GW9662. In conclusion, our data suggested that simvastatin could enhance hematoma clearance and attenuate neurological deficits possibly by activating PPARγ.

Microglia and Monocytes/Macrophages Polarization Reveal Novel Therapeutic Mechanism against Stroke

Stroke is a leading cause of morbidity and mortality worldwide, and consists of two types, ischemic and hemorrhagic. Currently, there is no effective treatment to increase the survival rate or improve the quality of life after ischemic and hemorrhagic stroke in the subacute to chronic phases. Therefore, it is necessary to establish therapeutic strategies to facilitate functional recovery in patients with stroke during both phases. Cell-based therapies, using microglia and monocytes/macrophages preconditioned by optimal stimuli and/or any therapies targeting these cells, might be an ideal therapeutic strategy for managing stroke. Microglia and monocytes/macrophages polarize to the classic pro-inflammatory type (M1-like) or alternative protective type (M2-like) by optimal condition. Cell-based therapies using M2-like microglia and monocytes/macrophages might be protective therapeutic strategies against stroke for three reasons. First, M2-like microglia and monocytes/monocytes secrete protective remodeling factors, thus prompting neuronal network recovery via tissue (including neuronal) and vascular remodeling. Second, these cells could migrate to the injured hemisphere through the blood–brain barrier or choroid–plexus. Third, these cells could mitigate the extent of inflammation-induced injuries by suitable timing of therapeutic intervention. Although future translational studies are required, M2-like microglia and monocytes/macrophages therapies are attractive for managing stroke based on their protective functions.

Clinical quantitative susceptibility mapping (QSM): Biometal imaging and its emerging roles in patient care

Quantitative susceptibility mapping (QSM) has enabled magnetic resonance imaging (MRI) of tissue magnetic susceptibility to advance from simple qualitative detection of hypointense blooming artifacts to precise quantitative measurement of spatial biodistributions. QSM technology may be regarded to be sufficiently developed and validated to warrant wide dissemination for clinical applications of imaging isotropic susceptibility, which is dominated by metals in tissue, including iron and calcium. These biometals are highly regulated as vital participants in normal cellular biochemistry, and their dysregulations are manifested in a variety of pathologic processes. Therefore, QSM can be used to assess important tissue functions and disease. To facilitate QSM clinical translation, this review aims to organize pertinent information for implementing a robust automated QSM technique in routine MRI practice and to summarize available knowledge on diseases for which QSM can be used to improve patient care. In brief, QSM can be generated with postprocessing whenever gradient echo MRI is performed. QSM can be useful for diseases that involve neurodegeneration, inflammation, hemorrhage, abnormal oxygen consumption, substantial alterations in highly paramagnetic cellular iron, bone mineralization, or pathologic calcification; and for all disorders in which MRI diagnosis or surveillance requires contrast agent injection. Clinicians may consider integrating QSM into their routine imaging practices by including gradient echo sequences in all relevant MRI protocols.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2017;46:951-971.

Microglial-mediated PDGF-CC activation increases cerebrovascular permeability during ischemic stroke

Treatment of acute ischemic stroke with the thrombolytic tissue plasminogen activator (tPA) can significantly improve neurological outcomes; however, thrombolytic therapy is associated with an increased risk of intra-cerebral hemorrhage (ICH). Previously, we demonstrated that during stroke tPA acting on the parenchymal side of the neurovascular unit (NVU) can increase blood–brain barrier (BBB) permeability and ICH through activation of latent platelet-derived growth factor-CC (PDGF-CC) and signaling by the PDGF receptor-α (PDGFRα). However, in vitro, activation of PDGF-CC by tPA is very inefficient and the mechanism of PDGF-CC activation in the NVU is not known. Here, we show that the integrin Mac-1, expressed on brain microglia/macrophages (denoted microglia throughout), acts together with the endocytic receptor LRP1 in the NVU to promote tPA-mediated activation of PDGF-CC. Mac-1-deficient mice (Mac-1^−/−) are protected from tPA-induced BBB permeability but not from permeability induced by intracerebroventricular injection of active PDGF-CC. Immunofluorescence analysis demonstrates that Mac-1, LRP1, and the PDGFRα all localize to the NVU of arterioles, and following middle cerebral artery occlusion (MCAO) Mac-1^−/− mice show significantly less PDGFRα phosphorylation, BBB permeability, and infarct volume compared to wild-type mice. Bone-marrow transplantation studies indicate that resident CD11b⁺ cells, but not bone-marrow-derived leukocytes, mediate the early activation of PDGF-CC by tPA after MCAO. Finally, using a model of thrombotic stroke with late thrombolysis, we show that wild-type mice have an increased incidence of spontaneous ICH following thrombolysis with tPA 5 h after MCAO, whereas Mac-1^−/− mice are resistant to the development of ICH even with late tPA treatment. Together, these results indicate that Mac-1 and LRP1 act as co-factors for the activation of PDGF-CC by tPA in the NVU, and suggest a novel mechanism for tightly regulating PDGFRα signaling in the NVU and controlling BBB permeability.

Analysis of three surgical treatments for spontaneous supratentorial intracerebral hemorrhage

This retrospective study aimed to evaluate the effectiveness and safety of 3 surgical procedures for Spontaneous Supratentorial Intracerebral Hemorrhage (SICH).A total of 63 patients with SICH were randomized into 3 groups. Group A (n = 21) underwent craniotomy surgery, group B (n = 22) underwent burr hole, urokinase infusion and catheter drainage, and group C (n = 20) underwent neuroendoscopic surgery. The hematoma evacuation rate of the operation was analyzed by 3D Slice software and the average surgery time, visualization during operation, decompressive effect, mortality, Glasgow Coma Scale (GCS) improvement, complications include rebleeding, pneumonia, intracranial infection were also compared among 3 groups.All procedures were successfully completed and the hematoma evacuation rate was significant differences among 3 groups which were 79.8%, 43.1%, 89.3% respectively (P < .01), and group C was the highest group. Group B was smallest traumatic one and shared the shortest operation time, but for the lack of hemostasis, it also the highest rebleeding group (P = .03). Although there were different in complications, but there was no significant in pneumonia, intracranial infection, GCS improvement and mortality rate.All these 3 methods had its own advantages and shortcomings, and every approach had its indications for SICH. Although for neuroendoscopic technical's minimal invasive, direct vision, effectively hematoma evacuation rate, and the relatively optimistic result, it might be a more promising approach for SICH.

Neuroprotective Mechanisms of Melatonin in Hemorrhagic Stroke

Hemorrhagic stroke which consists of subarachnoid hemorrhage and intracerebral hemorrhage is a dominant cause of death and disability worldwide. Although great efforts have been made, the physiological mechanisms of these diseases are not fully understood and effective pharmacological interventions are still lacking. Melatonin (N-acetyl-5-methoxytryptamine), a neurohormone produced by the pineal gland, is a broad-spectrum antioxidant and potent free radical scavenger. More importantly, there is extensive evidence demonstrating that melatonin confers neuroprotective effects in experimental models of hemorrhagic stroke. Multiple molecular mechanisms such as antioxidant, anti-apoptosis, and anti-inflammation, contribute to melatonin-mediated neuroprotection against brain injury after hemorrhagic stroke. This review article aims to summarize current knowledge regarding the beneficial effects of melatonin in experimental models of hemorrhagic stroke and explores the underlying mechanisms. We propose that melatonin is a promising neuroprotective candidate that is worthy of further evaluation for its potential therapeutic applications in hemorrhagic stroke.

Injury mechanisms in acute intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is the most common hemorrhagic stroke subtype, and rates are increasing with an aging population. Despite an increase in research and trials of therapies for ICH, mortality remains high and no interventional therapy has been demonstrated to improve outcomes. We review known mechanisms of injury, recent clinical trial results, and newly discovered signaling pathways involved in hematoma clearance. Enthusiasm remains high for methods of minimally invasive clot removal as well as pharmacologic strategies to improve recovery after ICH, both of which are currently being evaluated in clinical trials. This article is part of the Special Issue entitled 'Cerebral Ischemia'.

Neutrophil polarization by IL-27 as a therapeutic target for intracerebral hemorrhage

Shortly after intracerebral hemorrhage, neutrophils infiltrate the intracerebral hemorrhage-injured brain. Once within the brain, neutrophils degranulate, releasing destructive molecules that may exacerbate brain damage. However, neutrophils also release beneficial molecules, including iron-scavenging lactoferrin that may limit hematoma/iron-mediated brain injury after intracerebral hemorrhage. Here, we show that the immunoregulatory cytokine interleukin-27 is upregulated centrally and peripherally after intracerebral hemorrhage. Data from rodent models indicate that interleukin-27 modifies neutrophil maturation in the bone marrow, suppressing their production of pro-inflammatory/cytotoxic products while increasing their production of beneficial iron-scavenging molecules, including lactoferrin. Finally, interleukin-27 or lactoferrin administration results in reduced edema, enhanced hematoma clearance, and improved neurological outcomes in an animal model of intracerebral hemorrhage. These results suggest that interleukin-27/lactoferrin-mediated modulations of neutrophil function may represent a therapeutically viable concept for the modification of neutrophils toward a “beneficial” phenotype for the treatment of intracerebral hemorrhage.

Neutrophils are important modulators of tissue damage after intracerebral hemorrhage (ICH), but how this function is regulated is not clear. Here, the authors show interleukin-27 promotes the tissue-protecting functions of neutrophils via, at least partly, the induction of lactoferrin to present a potential therapy for ICH.

Management of Spontaneous Intracerebral Hemorrhage

Purpose of Review

We review the current evidence for medical and surgical treatments of spontaneous intracerebral hemorrhage (ICH).

Recent Findings

Therapy with hemostatic agents (e.g. factor VIIa and tranexamic acid) if started early after bleeding onset may reduce hematoma expansion, but their clinical effectiveness has not been shown. Rapid anticoagulation reversal with prothrombin concentrates (PCC) plus vitamin K is the first choice in vitamin K antagonist-related ICH. In ICH related to dabigatran, anticoagulation can be rapidly reversed with idarucizumab. PCC are recommended for ICH related to FXa inhibitors, whereas specific reversal agents are not yet approved. While awaiting ongoing trials studying minimally invasive approaches or hemicraniectomy, the role of surgery in ICH remains to be defined. Therapies targeting downstream molecular cascades in order to prevent secondary neuronal damage are promising, but the complexity and multi-phased nature of ICH pathophysiology is challenging. Finally, in addition to blood pressure control, antithrombotic prevention after ICH has to consider the risk of recurrent bleeding as well as the risk of ischemic events.

Summary

Treatment of acute ICH remains challenging, and many promising interventions for acute ICH await further evidence from trials.

Minocycline in Acute Cerebral Hemorrhage: An Early Phase Randomized Trial

BACKGROUND AND PURPOSE

Minocycline is under investigation as a neurovascular protective agent for stroke. This study evaluated the pharmacokinetic, anti-inflammatory, and safety profile of minocycline after intracerebral hemorrhage.

METHODS

This study was a single-site, randomized controlled trial of minocycline conducted from 2013 to 2016. Adults ≥18 years with primary intracerebral hemorrhage who could have study drug administered within 24 hours of onset were included. Patients received 400 mg of intravenous minocycline, followed by 400 mg minocycline oral daily for 4 days. Serum concentrations of minocycline after the last oral dose and biomarkers were sampled to determine the peak concentration, half-life, and anti-inflammatory profile.

RESULTS

A total of 16 consecutive eligible patients were enrolled, with 8 randomized to minocycline. Although the literature supports a time to peak concentration (T_max) of 1 hour for oral minocycline, the T_max was estimated to be at least 6 hours in this cohort. The elimination half-life (available on 7 patients) was 17.5 hours (SD±3.5). No differences were observed in inflammatory biomarkers, hematoma volume, or perihematomal edema. Concentrations remained at neuroprotective levels (>3 mg/L) throughout the dosing interval in 5 of 7 patients.

CONCLUSIONS

In intracerebral hemorrhage, a 400 mg dose of minocycline was safe and achieved neuroprotective serum concentrations. However, oral administration led to delayed absorption in these critically ill patients and should not be used when rapid, high concentrations are desired. Given the safety and pharmacokinetic profile of minocycline in intracerebral hemorrhage and promising data in the treatment of ischemic stroke, intravenous minocycline is an excellent candidate for a prehospital treatment trial.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01805895.

RETRACTED: Effect of microRNA-129-5p targeting HMGB1-RAGE signaling pathway on revascularization in a collagenase-induced intracerebral hemorrhage rat model

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. An Expression of Concern for this article was previously published while an investigation was conducted (see related editorial: https://doi.org/10.1016/j.biopha.2022.113812). This retraction notice supersedes the Expression of Concern published earlier. Concern was raised about the reliability of the Western blot data in Figure 2A, which contain suspected image duplications within the β-actin blot, and appear to represent a distinct phenotype as found in many other publications, as detailed here: https://pubpeer.com/publications/83FD53A8F4C5B60E2187CBF9F29B01; and here: https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. Independent analysis confirmed these findings and also identified additional suspected image duplications within Figures 3 and 4A. The journal requested the corresponding author comment on these concerns and provide the associated raw data. The authors did not respond to this request and therefore the Editor-in-Chief decided to retract the article.

Efficacy of Laropiprant in Minimizing Brain Injury Following Experimental Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is one of the most devastating and disabling forms of stroke, yet effective treatments are still lacking. Prostaglandins and their receptors have been implicated in playing vital roles in ICH outcomes. Recently, laropiprant, a DP1 receptor antagonist, has been used in combination with niacin to abolish the prostaglandin D2-(PGD2)-induced flushing. Here, we test the hypothesis that laropiprant limits bleeding and rescues the brain from ICH. Wildtype (WT) and DP1-/- mice were subjected ICH and neurologic deficits and hemorrhagic lesion outcomes were evaluated at 72 hours after the ICH. To test the therapeutic potential of laropiprant, WT mice subjected to ICH were treated with laropiprant at 1 hour after the ICH. The putative effect of laropiprant on limiting hematoma expansion was tested by an in vivo tail bleeding cessation method and an ex vivo coagulation method. Finally, the roles of laropiprant on gliosis and iron accumulation were also investigated. A significant decrease in the injury volume was observed in DP1-/- as well as laropiprant-treated WT mice. The tail bleeding time was significantly lower in laropiprant group as compared with the vehicle group. Significantly lower Iba-1 and Perls' iron staining in DP1-/- and laropiprant-treated WT groups were observed. Altogether, the data suggest that laropiprant treatment post-ICH attenuates brain damage by targeting primary as well as secondary injuries.

Resveratrol Attenuates Neurodegeneration and Improves Neurological Outcomes after Intracerebral Hemorrhage in Mice

Intracerebral hemorrhage (ICH) is a devastating type of stroke with a substantial public health impact. Currently, there is no effective treatment for ICH. The purpose of the study was to evaluate whether the post-injury administration of Resveratrol confers neuroprotection in a pre-clinical model of ICH. To this end, ICH was induced in adult male CD1 mice by collagenase injection method. Resveratrol (10 mg/kg) or vehicle was administered at 30 min post-induction of ICH and the neurobehavioral outcome, neurodegeneration, cerebral edema, hematoma resolution and neuroinflammation were assessed. The Resveratrol treatment significantly attenuated acute neurological deficits, neurodegeneration and cerebral edema after ICH in comparison to vehicle treated controls. Further, Resveratrol treated mice exhibited improved hematoma resolution with a concomitant reduction in the expression of proinflammatory cytokine, IL-1β after ICH. Altogether, the data suggest the efficacy of post-injury administration of Resveratrol in improving acute neurological function after ICH.

Urokinase vs Tissue-Type Plasminogen Activator for Thrombolytic Evacuation of Spontaneous Intracerebral Hemorrhage in Basal Ganglia

Spontaneous intracerebral hemorrhage (ICH) is a devastating form of stroke, which leads to a high rate of mortality and poor neurological outcomes worldwide. Thrombolytic evacuation with urokinase-type plasminogen activator (uPA) or tissue-type plasminogen activator (tPA) has been showed to be a hopeful treatment for ICH. However, to the best of our knowledge, no clinical trials were reported to compare the efficacy and safety of these two fibrinolytics administrated following minimally invasive stereotactic puncture (MISP) in patients with spontaneous basal ganglia ICH. Therefore, the authors intended here to evaluate the differential impact of uPA and tPA in a retrospective study. In the present study, a total of 86 patients with spontaneous ICH in basal ganglia using MISP received either uPA (uPA group, n = 45) or tPA (tPA group, n = 41), respectively. The clinical baseline characteristics prior to the operation were collected. In addition, therapeutic responses were assessed by the short-term outcomes within 30 days postoperation, as well as long-term outcomes at 1 year postoperation. Our findings showed that, in comparison with tPA, uPA was able to better promote hematoma evacuation and ameliorate perihematomal edema, but the differences were not statistically significant. Moreover, the long-term functional outcomes of both groups were similar, with no statistical difference. In conclusion, these results provide evidence supporting that uPA and tPA are similar in the efficacy and safety for thrombolytic evacuation in combination with MISP in patients with spontaneous basal ganglia ICH.

Cordycepin confers neuroprotection in mice models of intracerebral hemorrhage via suppressing NLRP3 inflammasome activation

Neuroinflammation has been recognized as a major contributor to brain injury caused by intracerebral hemorrhage (ICH). Nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome acts as an important mediator of inflammatory response in various inflammation-related diseases including hemorrhagic insults. Cordycepin has recently been shown to possess anti-inflammatory effect; however, its role and the possible underlying mechanisms in ICH remain unclear. This study was designed to investigate the neuroprotective effect of cordycepin in mice models of ICH and to elucidate the underlying molecular mechanisms. ICH was induced in male ICR mice by injecting autologous blood infusion stereotactically. Cordycepin was then given intraperitoneally (i.p.) at 30 min after ICH induction. The results demonstrated that NLRP3 inflammasome was activated and exacerbated the inflammatory progression after ICH. Cordycepin treatment significantly alleviated neurological deficits, brain edema, and perihematomal tissue damage following ICH. These changes were accompanied by downregulated NLRP3 inflammasome components expression and a reduction of production and release of inflammasome substrates interleukin-1beta (IL-1β) and interleukin-18 (IL-18). Furthermore, cordycepin ameliorated neuronal death in the perihematomal regions, accompanied by a large reduction in the expression of high-mobility group protein B 1 (HMGB1) post-ICH. In conclusion, this study provides in vivo evidence that cordycepin confers neuroprotective effect in the models of ICH, possibly through the suppression of NLRP3 inflammasome activation.

Mfsd2a (Major Facilitator Superfamily Domain Containing 2a) Attenuates Intracerebral Hemorrhage-Induced Blood-Brain Barrier Disruption by Inhibiting Vesicular Transcytosis

BACKGROUND

Blood-brain barrier (BBB) disruption aggravates brain injury induced by intracerebral hemorrhage (ICH); however, the mechanisms of BBB damage caused by ICH remain elusive. Mfsd2a (major facilitator superfamily domain containing 2a) has been known to play an essential role in BBB formation and function. In this study, we investigated the role and underlying mechanisms of Mfsd2a in BBB permeability regulation after ICH.

METHODS AND RESULTS

Using ICH models, we found that Mfsd2a protein expression in perihematomal brain tissues was significantly decreased after ICH. Knockdown and knockout of Mfsd2a in mice markedly increased BBB permeability, neurological deficit score, and brain water contents after ICH, and these were rescued by overexpressing Mfsd2a in perihematomas. Moreover, we found that Mfsd2a regulation of BBB permeability after ICH correlated with changes in vesicle number. Expression profiling of tight junction proteins showed no differences in Mfsd2a knockdown, Mfsd2a knockout, and Mfsd2a overexpression mice. However, using electron microscopy following ICH, we observed a significant increase in pinocytotic vesicle number in Mfsd2a knockout mice and decreased the number of pinocytotic vesicles in mouse brains with Mfsd2a overexpression. Finally, using multiple reaction monitoring, we screened out 3 vesicle trafficking-related proteins (Srgap2, Stx7, and Sec22b) from 31 vesicle trafficking-related proteins that were markedly upregulated in Mfsd2a knockout mice compared with controls after ICH.

CONCLUSIONS

In summary, our results suggest that Mfsd2a may protect against BBB injury by inhibiting vesicular transcytosis following ICH.

PD-L1 (Programmed Death Ligand 1) Protects Against Experimental Intracerebral Hemorrhage-Induced Brain Injury

BACKGROUND AND PURPOSE

Intracerebral hemorrhage (ICH) is a neurologically destructive stroke, for which no valid treatment is available. This preclinical study examined the therapeutic effect of PD-L1 (programmed death ligand 1), a B7 family member and a ligand for both PD-1 (programmed death 1) and B7-1 (CD80), in a murine ICH model.

METHODS

ICH was induced by injecting autologous blood into 252 male C57BL/6 and Rag1^-/- mice. One hour later, ICH mice were randomly assigned to receive an intraperitoneal injection of vehicle, PD-L1, or anti-PD-L1 antibody. Neurological function was assessed along with brain edema, brain infiltration of immune cells, blood-brain barrier integrity, neuron death, and mTOR (mammalian target of rapamycin) pathway products.

RESULTS

PD-L1 significantly attenuated neurological deficits, reduced brain edema, and decreased hemorrhage volume in ICH mice. PD-L1 specifically downsized the number of brain-infiltrating CD4⁺ T cells and the percentages of Th1 and Th17 cells but increased the percentages of Th2 and regulatory T cells. In the PD-L1-treated group, we observed an amelioration of the inflammatory milieu, decreased cell death, and enhanced blood-brain barrier integrity. PD-L1 also inhibited the mTOR pathway. The administration of anti-PD-L1 antibody produced the opposite effects to those of PD-L1 in ICH mice.

CONCLUSIONS

PD-L1 provided protection from the damaging consequences of ICH.

Colony stimulating factor 1 receptor inhibition eliminates microglia and attenuates brain injury after intracerebral hemorrhage

Microglia are the first responders to intracerebral hemorrhage, but their precise role in intracerebral hemorrhage remains to be defined. Microglia are the only type of brain cells expressing the colony-stimulating factor 1 receptor, a key regulator for myeloid lineage cells. Here, we determined the effects of a colony-stimulating factor 1 receptor inhibitor (PLX3397) on microglia and the outcome in the context of experimental mouse intracerebral hemorrhage. We show that PLX3397 effectively depleted microglia, and the depletion of microglia was sustained after intracerebral hemorrhage. Importantly, colony-stimulating factor 1 receptor inhibition attenuated neurodeficits and brain edema in two experimental models of intracerebral hemorrhage induced by injection of collagenase or autologous blood. The benefit of colony-stimulating factor 1 receptor inhibition was associated with reduced leukocyte infiltration in the brain and improved blood-brain barrier integrity after intracerebral hemorrhage, and each observation was independent of lesion size or hematoma volume. These results demonstrate that suppression of colony-stimulating factor 1 receptor signaling ablates microglia and confers protection after intracerebral hemorrhage.

Identification of two phosphorylation sites essential for annexin A1 in blood-brain barrier protection after experimental intracerebral hemorrhage in rats

Annexin A1 has been reported to exert a blood-brain barrier protection. This study was designed to examine the role of annexin A1 in intracerebral hemorrhage-induced blood-brain barrier dysfunction. A collagenase intracerebral hemorrhage model was performed in adult male Sprague Dawley rats. First, a possible relationship between annexin A1 and intracerebral hemorrhage pathology was confirmed by a loss of annexin A1 in the cerebrovascular endothelium and serum of intracerebral hemorrhage rats, and the rescue effects of i.v. administration of human recombinant annexin A1 in vivo and annexin A1 overexpression in vitro on the barrier function of brain microvascular endothelial cells exposed to intracerebral hemorrhage stimulus. Second, we found that intracerebral hemorrhage significantly increased the phosphorylation ratio of annexin A1 at the serine/threonine residues. Finally, based on site-specific mutagenesis, we identified two phosphorylation sites (a) annexin A1 phosphorylation at threonine 24 is required for its interaction with actin cytoskeleton, and (b) phosphorylation at serine27 is essential for annexin A1 secretion, both of which were essential for maintaining cytoskeleton integrity and paracellular permeability. In conclusion, annexin A1 prevents intracerebral hemorrhage-induced blood-brain barrier dysfunction in threonine 24 and serine27 phosphorylation-dependent manners. Annexin A1 phosphorylation may be a self-help strategy in brain microvascular endothelial cells after intracerebral hemorrhage; however, that was almost completely abolished by the intracerebral hemorrhage-induced loss of annexin A1.

Adoptive Regulatory T-cell Therapy Attenuates Perihematomal Inflammation in a Mouse Model of Experimental Intracerebral Hemorrhage

The CD4+CD25+ regulatory T cells (Tregs), an innate immunomodulator, suppress cerebral inflammation and maintain immune homeostasis in multiple central nervous system injury, but its role in intracerebral hemorrhage (ICH) has not been fully characterized. This study investigated the effect of Tregs on brain injury using the mouse ICH model, which is established by autologous blood infusion. The results showed that tail intravenous injection of Tregs significantly reduced brain water content and Evans blue dye extravasation of perihematoma at day (1, 3 and 7), and improved short- and long-term neurological deficits following ICH in mouse model. Tregs treatment reduced the content of pro-inflammatory cytokines interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and malondialdehyde, while increasing the superoxide dismutase (SOD) enzymatic activity at day (1, 3 and 7) following ICH. Furthermore, Tregs treatment obviously reduced the number of NF-κB+, IL-6+, TUNEL+ and active caspase-3+ cells at day 3 after ICH. These results indicate that adoptive transfer of Tregs may provide neuroprotection following ICH in mouse models.

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.

T lymphocytes infiltration promotes blood-brain barrier injury after experimental intracerebral hemorrhage

T lymphocytes migrate into the brain after intracerebral hemorrhage (ICH) and promote cerebral inflammation, thus exacerbating neuronal injury. However, the relationship between of T lymphocytes infiltration and blood-brain barrier (BBB) injury after ICH has not been clarified. In this study, we investigated the spatial-temporal distribution of infiltrating T lymphocytes after ICH in C57BL/6 mice by immunofluorescence and flow cytometry, and the accompanying change rules of BBB permeability were detected by Evans blue dye leakage and tight junction protein expression. Furthermore, T lymphocyte-deficient nude mice and T lymphocyte-decreased C57BL/6 mice treated with fingolimod were used to verify the relationship between T lymphocytes infiltration and BBB leakage after ICH. Here, we reported that brain-infiltrating T lymphocytes in the hemorrhagic hemisphere began to accumulate on the first day and peaked on the fifth day after ICH; BBB leakage also at peaked on the fifth day. Moreover, T lymphocyte-deficient nude mice showed minor BBB leakage after ICH compared with C57BL/6 control mice. Similarly, fingolimod treatment can significantly decrease T lymphocyte infiltration and promote BBB integrity compared with a vehicle control. Overall, our results suggested that suppression of T lymphocyte infiltration may be a novel way to improve BBB integrity after ICH.

Isoliquiritigenin alleviates early brain injury after experimental intracerebral hemorrhage via suppressing ROS- and/or NF-κB-mediated NLRP3 inflammasome activation by promoting Nrf2 antioxidant pathway

BACKGROUND

Intracerebral hemorrhage (ICH) induces potently oxidative stress responses and inflammatory processes. Isoliquiritigenin (ILG) is a flavonoid with a chalcone structure and can activate nuclear factor erythroid-2 related factor 2 (Nrf2)-mediated antioxidant system, negatively regulate nuclear factor-κB (NF-κB) and nod-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome pathways, but its role and potential molecular mechanisms in the pathology following ICH remain unclear. The present study aimed to explore the effects of ILG after ICH and underlying mechanisms.

METHODS

ICH model was induced by collagenase IV (0.2 U in 1 μl sterile normal saline) in male Sprague-Dawley rats weighing 280-320 g. Different doses of ILG (10, 20, or 40 mg/kg) was administrated intraperitoneally at 30 min, 12 h, 24 h, and 48 h after modeling, respectively. Rats were intracerebroventricularly administrated with control scramble small interfering RNA (siRNA) or Nrf2 siRNA at 24 h before ICH induction, and after 24 h, ICH model was established with or without ILG (20 mg/kg) treatment. All rats were dedicated at 24 or 72 h after ICH. Neurological deficits, histological damages, brain water content (BWC), blood-brain barrier (BBB) disruption, and neuronal degeneration were evaluated; quantitative real-time RT-PCR (qRT-PCR), immunohistochemistry/immunofluorescence, western blot, and enzyme-linked immunosorbent assay (ELISA) were carried out; catalase, superoxide dismutase activities and reactive oxygen species (ROS), and glutathione/oxidized glutathione contents were measured.

RESULTS

ILG (20 and 40 mg/kg) markedly alleviated neurological deficits, histological damages, BBB disruption, brain edema, and neuronal degeneration, but there was no significant difference between two dosages. ILG (20 mg/kg) significantly suppressed the NF-κB and NLRP3 inflammasome pathways and activated Nrf2-mediated antioxidant system. Gene silencing of Nrf2 aggravated the neurological deficits, brain edema, and neuronal degeneration and increased the protein levels of NF-κB p65, NLRP3 inflammasome components, and IL-1β. ILG delivery significantly attenuated the effects of Nrf2 siRNA interference mentioned above.

CONCLUSIONS

Intraperitoneal administration of ILG after ICH reduced early brain impairments and neurological deficits, and the mechanisms were involved in the regulation of ROS and/or NF-κB on the activation of NLRP3 inflammasome pathway by the triggering of Nrf2 activity and Nrf2-induced antioxidant system. In addition, our experimental results may make ILG a potential candidate for a novel therapeutical strategy for ICH.

White Matter Injury and Recovery after Hypertensive Intracerebral Hemorrhage

Hypertensive intracerebral hemorrhage (ICH) could very probably trigger white matter injury in patients. Through the continuous study of white matter injury after hypertensive ICH, we achieve a more profound understanding of the pathophysiological mechanism of its occurrence and development. At the same time, we found a series of drugs and treatment methods for the white matter repair. In the current reality, the research paradigm of white matter injury after hypertensive ICH is relatively obsolete or incomplete, and there are still lots of deficiencies in the research. In the face of the profound changes of stroke research perspective, we believe that the combination of the lenticulostriate artery, nerve nuclei of the hypothalamus-thalamus-basal ganglia, and the white matter fibers located within the capsula interna will be beneficial to the research of white matter injury and repair. This paper has classified and analyzed the study of white matter injury and repair after hypertensive ICH and also rethought the shortcomings of the current research. We hope that it could help researchers further explore and study white matter injury and repair after hypertensive ICH.

Quantitative assessment on blood-brain barrier permeability of acute spontaneous intracerebral hemorrhage in basal ganglia: a CT perfusion study

PURPOSE

Blood-brain barrier (BBB) damage aggravates perihematomal edema, and edema volume predicts prognosis independently. But the BBB permeability at the late stage of acute intracerebral hemorrhage (ICH) patients is uncertain. We aimed to assess the BBB permeability of spontaneous basal ganglia ICH using computed tomographic perfusion (CTP) and investigates its relationship with hematoma and perihematomal edema volume.

METHODS

We performed CTP on 54 consecutive ICH patients within 24 to 72 h after symptom onset. Permeability-surface area product (PS) derived from CTP imaging was measured in hematoma, "high-PS spot," perihematoma, normal-appearing, hemispheric, and contralateral regions. Hematoma and edema volumes were calculated from non-contrast CT.

RESULTS

"High-PS spot" and perihematoma regions had higher PS than the contralateral regions (p < 0.001). Hematoma PS was lower than that in the contralateral regions (p < 0.001). Perihematoma PS of the large-hematoma group was higher than that of the small-hematoma group (p = 0.011). Perihematomal edema volume correlated positively with hematoma volume (β = 0.864, p < 0.001) and perihematoma PS (β = 0.478, p < 0.001). Perihematoma PS correlated positively with hematoma volume (β = 0.373, p = 0.005).

CONCLUSIONS

Locally elevated perihematoma PS was found in most spontaneous basal ganglia ICH patients within 24 to 72 h after symptom onset. Perihematoma PS was higher in larger hematomas and was associated with larger edema volume. At this period, BBB leakage is likely to be an important factor in edema formation.

CM352 Reduces Brain Damage and Improves Functional Recovery in a Rat Model of Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is an acute neurological disorder with high mortality and no effective treatment. In addition to the initial bleeding event, rebleeding and hematoma expansion are associated with poor outcome in these patients. We studied the effectiveness of the new antifibrinolytic agent CM352, a short-half-life matrix metalloproteinase inhibitor, for achieving early hemostasis and improving functional recovery in a rat model of collagenase-induced ICH.

METHODS AND RESULTS

ICH was induced by striatal injection of collagenase, and 1 hour later, rats received an intravenous injection of saline (n=6) or CM352 (1 mg/kg, n=6). Hematoma (basal and after 3 and 24 hours) and lesion (14 days) volumes were quantified on T2-weighted (T2) magnetic resonance images. Neurological and functional recovery was evaluated by using Bederson score and a cylinder test (basal, 24 hours, and 14 days). Early treatment (1 hour) with CM352 was efficient reducing hematoma expansion at 3 hours (P<0.01) and, more markedly, at 24 hours (P<0.01). Decreased bleeding after antifibrinolytic treatment was accompanied by reduced interleukin-6 levels at 3 hours (P<0.05) and smaller lesion volume at 14 days (P<0.01). CM352 drastically reduced sensorimotor impairment (cylinder test) after ICH in rats at 24 hours (P<0.01) and 14 days (P<0.01). Similarly, it also attenuated neurological deficit (Bederson scale) at 24 hours (P<0.01) and 14 days (P<0.01). Interestingly, late (3 hours) CM352 administration also resulted in reduced lesion size and better functional outcome.

CONCLUSIONS

CM352, a new antifibrinolytic agent and matrix metalloproteinase inhibitor, effectively prevented hematoma growth and reduced lesion size in ICH in association with improved functional and neurological recovery.

Recombinant Gas6 augments Axl and facilitates immune restoration in an intracerebral hemorrhage mouse model

Axl, a tyrosine kinase receptor, was recently identified as an essential component regulating innate immune response. Suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 are potent Axl-inducible negative inflammatory regulators. This study investigated the role of Axl signaling pathway in immune restoration in an autologous blood-injection mouse model of intracerebral hemorrhage. Recombinant growth arrest-specific 6 (Gas6) and R428 were administrated as specific agonist and antagonist. In vivo knockdown of Axl or suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 by siRNA was applied. After intracerebral hemorrhage, the expression of endogenous Axl, soluble Axl, and Gas6 was increased, whereas the expression of suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 was inhibited. Recombinant growth arrest-specific 6 administration alleviated brain edema and improved neurobehavioral performances. Moreover, enhanced Axl phosphorylation with cleavage of soluble Axl (sAxl), and an upregulation of suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 were observed. In vivo knockdown of Axl and R428 administration both abolished the effect of recombinant growth arrest-specific 6 on brain edema and also decreased the expression suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3. In vivo knockdown of suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3 aggravated cytokine releasing despite of recombinant growth arrest-specific 6. In conclusion, Axl plays essential role in immune restoration after intracerebral hemorrhage. And recombinant growth arrest-specific 6 attenuated brain injury after intracerebral hemorrhage, probably by enhancing Axl phosphorylation and production of suppressor of cytokine signaling 1 and suppressor of cytokine signaling 3.

Depletion of microglia exacerbates postischemic inflammation and brain injury

Brain ischemia elicits microglial activation and microglia survival depend on signaling through colony-stimulating factor 1 receptor (CSF1R). Although depletion of microglia has been linked to worse stroke outcomes, it remains unclear to what extent and by what mechanisms activated microglia influence ischemia-induced inflammation and injury in the brain. Using a mouse model of transient focal cerebral ischemia and reperfusion, we demonstrated that depletion of microglia via administration of the dual CSF1R/c-Kit inhibitor PLX3397 exacerbates neurodeficits and brain infarction. Depletion of microglia augmented the production of inflammatory mediators, leukocyte infiltration, and cell death during brain ischemia. Of note, microglial depletion-induced exacerbation of stroke severity did not solely depend on lymphocytes and monocytes. Importantly, depletion of microglia dramatically augmented the production of inflammatory mediators by astrocytes after brain ischemia . In vitro studies reveal that microglia restricted ischemia-induced astrocyte response and provided neuroprotective effects. Our findings suggest that neuroprotective effects of microglia may result, in part, from its inhibitory action on astrocyte response after ischemia.

Autophagy, Endoplasmic Reticulum Stress and the Unfolded Protein Response in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a subtype of stroke that is followed by primary and secondary brain injury. As a result of the injury, cell metabolism is disrupted and a series of stress responses are activated, such as endoplasmic reticulum (ER) stress and the unfolded protein response (UPR), leading to the re-establishment of cell homeostasis or cell death. As an important mechanism of cell homeostasis, autophagy has been widely studied, and the associations between autophagy, ER stress, and the UPR have also been demonstrated. Whether these mechanisms are beneficial or detrimental remains a matter of controversy, but there is no doubt as to their vital functions. An understanding of the mechanisms of injury and recovery after ICH is crucial to develop therapeutic strategies. In this review, we summarize the related studies and highlight the roles of autophagy, ER stress, and the UPR in disease, especially in ICH. We also provide an overview of therapeutic approaches that target autophagy, and we discuss the prospects for modulating autophagy, ER stress, and UPR mechanisms in ICH therapy.

Cerebral Microbleeds, Hypertension, and Intracerebral Hemorrhage in Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy

Background

Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common genetic cause of stroke. In addition to ischemic stroke, CADASIL predisposes to development of cerebral microbleeds (CMB). CMB and hypertension are known to be associated with intracerebral hemorrhage (ICH). The purpose of this study was to analyze the relationships among CMB, hypertension, and ICH in CADASIL.

Materials and methods

We enrolled 94 genetically confirmed CADASIL patients from 76 unrelated families at Jeju National University Hospital (Korea) between March 2012 and February 2015. We analyzed CMB presence, number, and distribution on susceptibility-weighted imaging MRI using the microbleed anatomical rating scale. Multiple logistic regression was used to determine factors associated with the presence of CMB and ICH.

Results

CMB were observed in 62 patients (66%), median number of CMB per patient was 4 (range 0–121). Twenty-two ICHs were found in 16 patients (17%). There was incongruence between the most common site of CMB (thalamus) and that of ICH (basal ganglia). Hypertension was independently associated with the presence of CMB (multiple regression OR, 2.71; 95% CI 1.02–7.18, p < 0.05), and CMB ≥ 9 (highest third) was significantly associated with the presence of ICH (multiple regression OR = 9.50, 95% CI 1.08–83.71, p < 0.05).

Conclusion

In this CADASIL sample, presence of hypertension was independently associated with CMB presence, and CMB burden was independently associated with ICH. Incongruence of sites for CMB and ICH is currently unexplained and requires further study.

Scalp acupuncture attenuates neurological deficits in a rat model of hemorrhagic stroke

BACKGROUND

Hemorrhagic stroke accounts for approximately 15% of all stroke cases, and is associated with high morbidity and mortality. Limited human studies suggested that scalp acupuncture could facilitate functional recovery after cerebral hemorrhage. In the current study, we used an animal model of cerebral hemorrhage to examine the potential effects of scalp acupuncture.

METHODS

Adult male Sprague-Dawley rats received autologous blood (50μL) into the right caudate nucleus on the right side under pentobarbital anesthesia, and then received scalp acupuncture (DU20 through GB7 on the lesion side) or sham acupuncture (1cm to the right side of the acupoints) (n=10 per group). A group of rats receiving autologous blood into the caudate nucleus but no other intervention, as well as a group of rats receiving anesthesia but no blood injection to the brain (n=10 per group) were included as additional controls. Composite neuroscore, corner turn test, forelimb placing test, wire hang task and beam walking were used to evaluate the behavior of rats. Hematoxylin and Eosin (HE) staining was used to observe the histopathological changes. Western blot was used to detect the content of tumor necrosis factor alpha (TNF-α) and nuclear factor-KappaB (NFκB) protein expression.

RESULTS

Scalp acupuncture attenuated neurological deficits (p<0.01 or <0.05 vs. sham acupuncture using a variety of behavioral tests) at 1-7days after the treatment. The brain content of TNF-α and NFκB was decreased (p<0.01 for both).

CONCLUSIONS

Scalp acupuncture could improve neurological deficits in a rat model of hemorrhagic stroke.

A TSPO ligand attenuates brain injury after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating disease without effective treatment. After ICH, the immediate infiltration of leukocytes and activation of microglia are accompanied by a rapid up-regulation of the 18-kDa translocator protein (TSPO). TSPO ligands have shown anti-inflammatory and neuroprotective properties in models of CNS injury. In this study, we determined the impact of a TSPO ligand, etifoxine, on brain injury and inflammation in 2 mouse models of ICH. TSPO was up-regulated in Iba1⁺ cells from brains of patients with ICH and in CD11b⁺CD45^int cells from mice subjected to collagenase-induced ICH. Etifoxine significantly reduced neurodeficits and perihematomal brain edema after ICH induction by injection of either autologous blood or collagenase. In collagenase-induced ICH mice, the protection of etifoxine was associated with reduced leukocyte infiltration into the brain and microglial production of IL-6 and TNF-α. Etifoxine improved blood–brain barrier integrity and diminished cell death. Notably, the protective effect of etifoxine was abolished in mice depleted of microglia by using a colony-stimulating factor 1 receptor inhibitor. These results indicate that the TSPO ligand etifoxine attenuates brain injury and inflammation after ICH. TSPO may be a viable therapeutic target that requires further investigations in ICH.—Li, M., Ren, H., Sheth, K. N., Shi, F.-D., Liu, Q. A TSPO ligand attenuates brain injury after intracerebral hemorrhage.

Medical Treatment for Spontaneous Anticoagulation-Related Intracerebral Hemorrhage in the Netherlands

BACKGROUND

Spontaneous anticoagulation-related intracerebral hemorrhage accounts for up to a quarter of spontaneous intracerebral hemorrhage cases and is associated with higher hematoma volume and a worse outcome. Guidelines recommend rapid anticoagulant reversal but mode and timing are not specified and optimal strategy is uncertain. Variability in everyday practice is unknown.

METHODS

An invitation to a web-based survey was sent to 85 Dutch stroke neurologists in different hospitals, with questions about importance, timing, and medical management of spontaneous anticoagulation-related intracerebral hemorrhage.

RESULTS

In total, 61 (72%) neurologists completed the survey. Nearly all (97%) deemed rapid anticoagulant reversal important. A local guideline for management of anticoagulant reversal was used in 80% of the hospitals. Most neurologists (56%) estimated anticoagulant reversal in anticoagulation-related intracerebral hemorrhage to start later than intravenous thrombolysis in ischemic stroke. Few (5%) thought it was quicker. A minority (28%) of the hospitals started anticoagulation reversal without waiting for laboratory test results or consulting a specialist in hemostasis. Prothrombin complex concentrate was used by all neurologists for vitamin K antagonist reversal and by most (74%) for reversal of thrombin inhibitors and factor Xa inhibitors (72%). Anticoagulation reversal was initiated at the emergency department according to 89% of the respondents.

CONCLUSION

Variability in logistics in acute management of spontaneous anticoagulation-related intracerebral hemorrhage was demonstrated. Anticoagulant reversal is deemed important, but is estimated to have a longer door-to-needle time than alteplase in thrombolysis for ischemic stroke by most neurologists. Several delaying factors were found. These factors might have an impact on outcome.

Anti-high mobility group box-1 (HMGB1) antibody inhibits hemorrhage-induced brain injury and improved neurological deficits in rats

As one of the most lethal stroke subtypes, intracerebral hemorrhage (ICH) is acknowledged as a serious clinical problem lacking effective treatment. Available evidence from preclinical and clinical studies suggests that inflammatory mechanisms are involved in the progression of ICH-induced secondary brain injury. High mobility group box-1 (HMGB1) is a ubiquitous and abundant nonhistone DNA-binding protein, and is also an important proinflammatory molecule once released into the extracellular space from the nuclei. Here, we show that treatment with neutralizing anti-HMGB1 mAb (1 mg/kg, i.v. twice) remarkably ameliorated ICH-injury induced by local injection of collagenase IV in the striatum of rats. Administration of anti-HMGB1 mAb inhibited the release of HMGB1 into the extracellular space in the peri-hematomal region, reduced serum HMGB1 levels and decreased brain edema by protecting blood-brain barrier integrity, in association with decreased activated microglia and the expression of inflammation-related factors at 24 h after ICH. Consequently, anti-HMGB1 mAb reduced the oxidative stress and improved the behavioral performance of rats. These results strongly indicate that HMGB1 plays a critical role in the development of ICH-induced secondary injury through the amplification of plural inflammatory responses. Intravenous injection of neutralizing anti-HMGB1 mAb has potential as a novel therapeutic strategy for ICH.

Secondary Hematoma Expansion and Perihemorrhagic Edema after Intracerebral Hemorrhage: From Bench Work to Practical Aspects

Intracerebral hemorrhages (ICH) represent about 10-15% of all strokes per year in the United States alone. Key variables influencing the long-term outcome after ICH are hematoma size and growth. Although death may occur at the time of the hemorrhage, delayed neurologic deterioration frequently occurs with hematoma growth and neuronal injury of the surrounding tissue. Perihematoma edema has also been implicated as a contributing factor for delayed neurologic deterioration after ICH. Cerebral edema results from both blood-brain barrier disruption and local generation of osmotically active substances. Inflammatory cellular mediators, activation of the complement, by-products of coagulation and hemolysis such as thrombin and fibrin, and hemoglobin enter the brain and induce a local and systemic inflammatory reaction. These complex cascades lead to apoptosis or neuronal injury. By identifying the major modulators of cerebral edema after ICH, a therapeutic target to counter degenerative events may be forthcoming.

Effectiveness of endoscopic surgery for supratentorial hypertensive intracerebral hemorrhage: a comparison with craniotomy

OBJECTIVE The goal of this study was to investigate the effectiveness and practicality of endoscopic surgery for treatment of supratentorial hypertensive intracerebral hemorrhage (HICH) compared with traditional craniotomy. METHODS The authors retrospectively analyzed 151 consecutive patients who were operated on for treatment of supratentorial HICH between January 2009 and June 2014 in the Department of Neurosurgery at Chinese PLA General Hospital. Patients were separated into an endoscopy group (82 cases) and a craniotomy group (69 cases), depending on the surgery they received. The hematoma evacuation rate was calculated using 3D Slicer software to measure the hematoma volume. Comparisons of operative time, intraoperative blood loss, Glasgow Coma Scale score 1 week after surgery, hospitalization time, and modified Rankin Scale score 6 months after surgery were also made between these groups. RESULTS There was no statistically significant difference in preoperative data between the endoscopy group and the craniotomy group (p > 0.05). The hematoma evacuation rate was 90.5% ± 6.5% in the endoscopy group and 82.3% ± 8.6% in the craniotomy group, which was statistically significant (p < 0.01). The operative time was 1.6 ± 0.7 hours in the endoscopy group and 5.2 ± 1.8 hours in the craniotomy group (p < 0.01). The intraoperative blood loss was 91.4 ± 93.1 ml in the endoscopy group and 605.6 ± 602.3 ml in the craniotomy group (p < 0.01). The 1-week postoperative Glasgow Coma Scale score was 11.5 ± 2.9 in the endoscopy group and 8.3 ± 3.8 in the craniotomy group (p < 0.01). The hospital stay was 11.6 ± 6.9 days in the endoscopy group and 13.2 ± 7.9 days in the craniotomy group (p < 0.05). The mean modified Rankin Scale score 6 months after surgery was 3.2 ± 1.5 in the endoscopy group and 4.1 ± 1.9 in the craniotomy group (p < 0.01). Patients had better recovery in the endoscopy group than in the craniotomy group. Data are expressed as the mean ± SD. CONCLUSIONS Compared with traditional craniotomy, endoscopic surgery was more effective, less invasive, and may have improved the prognoses of patients with supratentorial HICH. Endoscopic surgery is a promising method for treatment of supratentorial HICH. With the development of endoscope technology, endoscopic evacuation will become more widely used in the clinic. Prospective randomized controlled trials are needed.

Nicotinamide mononucleotide attenuates brain injury after intracerebral hemorrhage by activating Nrf2/HO-1 signaling pathway

Replenishment of NAD⁺ has been shown to protect against brain disorders such as amyotrophic lateral sclerosis and ischemic stroke. However, whether this intervention has therapeutic effects in intracerebral hemorrhage (ICH) is unknown. In this study, we sought to determine the potential therapeutic value of replenishment of NAD⁺ in ICH. In a collagenase-induced ICH (cICH) mouse model, nicotinamide mononucleotide (NMN), a key intermediate of nicotinamide adenine dinucleotide (NAD⁺) biosynthesis, was administrated at 30 minutes post cICH from tail vein to replenish NAD⁺. NMN treatment did not decrease hematoma volume and hemoglobin content. However, NMN treatment significantly reduced brain edema, brain cell death, oxidative stress, neuroinflammation, intercellular adhesion molecule-1 expression, microglia activation and neutrophil infiltration in brain hemorrhagic area. Mechanistically, NMN enhanced the expression of two cytoprotective proteins: heme oxygenase 1 (HO-1) and nuclear factor-like 2 (Nrf2). Moreover, NMN increased the nuclear translocation of Nrf2 for its activation. Finally, a prolonged NMN treatment for 7 days markedly promoted the recovery of body weight and neurological function. These results demonstrate that NMN treats brain injury in ICH by suppressing neuroinflammation/oxidative stress. The activation of Nrf2/HO-1 signaling pathway may contribute to the neuroprotection of NMN in ICH.