Nuclear factor-κB activation in perihematomal brain tissue correlates with outcome in patients with intracerebral hemorrhage

An apolipoprotein E receptor mimetic peptide decreases blood-brain barrier permeability following intracerebral hemorrhage by inhibiting the CypA/MMP-9 signaling pathway via LRP1 activation

Apolipoprotein (Apo) E mimetic peptides down-regulate the inflammatory response and alleviate damage to secondary neurons after intracerebral hemorrhage (ICH). We designed a novel apoE receptor mimetic composed of the low-density lipoprotein receptor-associated protein-1 (LRP1) receptor-binding domain of apoE with 6 lysines (6KApoEp). The 6KApoEp peptide is small enough to penetrate the blood-brain barrier (BBB) and modulate the inflammatory response during damage to the central nervous system. LRP1 inhibits the CypA/MMP-9 pathway and reduces BBB damage. Thus, we examined the effects of 6KApoEp-LRP1 interaction. LRP1 and 6KApoEp interacted and co-localized in the pericytes. We established a Sprague-Dawley (SD) male rat model of ICH to observe the role of 6KApoEp in secondary injury after ICH. The expression levels of cyclophilin A (CypA), nuclear factor kappa-B (NF-κB) p65, and matrix metalloproteinase 9 (MMP-9) were increased, the expression levels of ZO-1, claudin-5, and occludin were decreased, and brain water content and BBB permeability increased in the ICH model. The expression of CypA, NF-κB, and MMP-9 decreased significantly around the hematoma, while the expression of tight junction-related proteins increased significantly in response to 6KApoEp, especially at the 100 μg/kg dose. LRP expression increased around the ICH focus in response to 6KApoEp treatment, thus increasing the influence on the expression of CypA, NF-κB, and MMP-9. We conclude that 6KApoEp inhibits the CypA/NF-κB/MMP-9 pathway by activating LRP1, resulting in reduced BBB damage and less brain edema around the ICH. These results provide the theoretical basis for improving the prognosis and treatment of ICH. Our results suggest that 6KApoEp activates LRP1, resulting in the attenuation of tight junction protein degradation (ZO-1, occludin, and claudin-5) via the CypA/NF-κB/MMP-9 signaling pathway. The increased tight junction protein levels improve the BBB and attenuate edema development in brain tissue around the hematoma following ICH.

Efficacy and Safety of Endoscopic Surgery Versus Craniotomy for Hypertensive Putamen Hemorrhage

OBJECTIVE

This study aimed to evaluate the efficacy and safety of neuroendoscopy for treating hypertensive putamen hemorrhage (HPH), compared with traditional craniotomy.

METHODS

We retrospectively analyzed 81 consecutive patients with HPH treated with neuroendoscopy (n=36) or craniotomy (n=45) in the Department of Neurosurgery at the Anhui Provincial Hospital Affiliated to Anhui Medical University between January 2015 and December 2017. We compared the clinical and radiographic outcomes, excluded 14 patients who did not meet the inclusion criteria. Patient characteristics in emergency room were recorded. In addition, hospitalization days, total cost during hospitalization, operative time, blood loss, evacuation rate, rebreeding, intracranial infection, pulmonary infection, epilepsy, hemorrhage of digestive tract, venous thrombus, hypoproteinemia, aphasia, oculomotor paralysis, mortality, Modified Rankin Scale score 6 months after surgery, and Glasgow Outcome Scale score 6 months after surgery were compared between the 2 groups.

RESULTS

Comparative analysis of preoperative patient data revealed no notable disparities. Neuroendoscopic surgery afford distinct benefits including reduced operative time, minimal patient blood loss, and enhanced efficacy in hematoma evacuation. However, the incidence of postoperative complications such as rebleeding, intracranial infections, pulmonary infections, postoperative epilepsy, hemorrhage of digestive tract, venous thrombus, hypoproteinemia, aphasia, and oculomotor paralysis did not significantly differ. In contrast, endoscopic techniques, relative to conventional craniotomy for hematoma evacuation, are characterized by less invasive incisions, a marked decrease in the duration of hospitalization, and a substantial reduction in associated healthcare costs. Furthermore, endoscopic techniques contribute to superior long-term recuperative outcomes in patients, without altering mortality rates.

CONCLUSIONS

In comparison to the conventional method of craniotomy, the utilization of neuroendoscopy in the treatment of hypertensive putamen hemorrhage (HPH) may offer a more efficacious, minimally invasive, and cost-effective approach. This alternative approach has the potential to decrease the length of hospital stays and improve long-term neurologic outcomes, without altering mortality rates.

GLP-1(7-36) protected against oxidative damage and neuronal apoptosis in the hippocampal CA region after traumatic brain injury by regulating ERK5/CREB

BACKGROUND

Glucagon-like peptide-1 (GLP-1) (7-36) amide, an endogenous active form of GLP-1, has been shown to modulate oxidative stress and neuronal cell survival in various neurological diseases.

OBJECTIVE

This study investigated the potential effects of GLP-1(7-36) on oxidative stress and apoptosis in neuronal cells following traumatic brain injury (TBI) and explored the underlying mechanisms.

METHODS

Traumatic brain injury (TBI) models were established in male SD rats for in vivo experiments. The extent of cerebral oedema was assessed using wet-to-dry weight ratios following GLP-1(7-36) intervention. Neurological dysfunction and cognitive impairment were evaluated through behavioural experiments. Histopathological changes in the brain were observed using haematoxylin and eosin staining. Oxidative stress levels in hippocampal tissues were measured. TUNEL staining and Western blotting were employed to examine cell apoptosis. In vitro experiments evaluated the extent of oxidative stress and neural apoptosis following ERK5 phosphorylation activation. Immunofluorescence colocalization of p-ERK5 and NeuN was analysed using immunofluorescence cytochemistry.

RESULTS

Rats with TBI exhibited neurological deterioration, increased oxidative stress, and enhanced apoptosis, which were ameliorated by GLP-1(7-36) treatment. Notably, GLP-1(7-36) induced ERK5 phosphorylation in TBI rats. However, upon ERK5 inhibition, oxidative stress and neuronal apoptosis levels were elevated, even in the presence of GLP-1(7-36).

CONCLUSION

In summary, this study suggested that GLP-1(7-36) suppressed oxidative damage and neuronal apoptosis after TBI by activating ERK5/CREB.

TonEBP: A Key Transcription Factor in Microglia Following Intracerebral Hemorrhage Induced-Neuroinflammation

Transcription factors within microglia contribute to the inflammatory response following intracerebral hemorrhage (ICH). Therefore, we employed bioinformatics screening to identify the potential transcription factor tonicity-responsive enhancer-binding protein (TonEBP) within microglia. Inflammatory stimuli can provoke an elevated expression of TonEBP in microglia. Nevertheless, the expression and function of microglial TonEBP in ICH-induced neuroinflammation remain ambiguous. In our recent research, we discovered that ICH instigated an increased TonEBP in microglia in both human and mouse peri-hematoma brain tissues. Furthermore, our results indicated that TonEBP knockdown mitigates lipopolysaccharide (LPS)-induced inflammation and the activation of NF-κB signaling in microglia. In order to more deeply comprehend the underlying molecular mechanisms of how TonEBP modulates the inflammatory response, we sequenced the transcriptomes of TonEBP-deficient cells and sought potential downstream target genes of TonEBP, such as Pellino-1 (PELI1). PELI has been previously reported to mediate nuclear factor-κB (NF-κB) signaling. Through the utilization of CUT & RUN, a dual-luciferase reporter, and qPCR, we confirmed that TonEBP is the transcription factor of Peli1, binding to the Peli1 promoter. In summary, TonEBP may enhance the LPS-induced inflammation and activation of NF-κB signaling via PELI1.

Acyclic retinoid peretinoin reduces hemorrhage-associated brain injury in vitro and in vivo

Peretinoin is an acyclic retinoid that stimulates retinoic acid receptors (NR1Bs) and produces therapeutic effects on hepatocellular cancer. We have previously shown that NR1B agonists such as Am80 and all trans-retinoic acid suppress pathogenic events in intracerebral hemorrhage. The present study addressed the actions of peretinoin and Am80 against cytotoxicity of a blood protease thrombin on cortico-striatal slice cultures obtained from neonatal rat brains. Application of 100 U/ml thrombin to the slice cultures for 72 h caused cell death in the cortical region and tissue shrinkage in the striatal region. Peretinoin (50 μM) and Am80 (1 μM) counteracted these cytotoxic effects of thrombin, and the effect of peretinoin and Am80 was blocked by LE540, an NR1B antagonist. A broad-spectrum kinase inhibitor K252a (3 μM) attenuated the cytoprotective effect of peretinoin in the cortical region, whereas a specific protein kinase A inhibitor KT5720 (1 μM) attenuated the protective effect of peretinoin in the cortical and the striatal regions. On the other hand, nuclear factor-κB (NF-κB) inhibitors such as pyrrolidine dithiocarbamate (50 μM) and Bay11-7082 (10 μM) prevented thrombin-induced shrinkage of the striatal region. Peretinoin and Am80 as well as Bay11-7082 blocked thrombin-induced nuclear translocation of NF-κB in striatal microglia and loss of striatal neurons. We also found that daily administration of peretinoin reduced histopathological injury and alleviated motor deficits in a mouse model of intracerebral hemorrhage. These results indicate that NR1B agonists including peretinoin may serve as a therapeutic option for hemorrhagic brain injury.

Serum β2-microglobulin is closely associated with 3-month outcome of acute intracerebral hemorrhage: a retrospective cohort study

BACKGROUND

Intracerebral hemorrhage (ICH) is a frequent type of hemorrhagic stroke. Numerous studies have suggested that inflammation plays an important role in the injury and recovery of ICH. β2-microglobulin (β2M) is an inflammatory indicator with an unclear association with ICH development. This study aimed to explore the role of β2M in the outcome of patients with ICH after 3 months of ICH onset.

METHODS

The β2M and other baseline information of 231 patients with ICH were assessed (83 females and 148 males). We followed up with all patients 3 months after ICH onset, and severe disability or a worse outcome was our main focus. We collected the serum β2M levels, National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) scores, and other relevant baseline information of each patient. We used multiple regression analysis to explore the association between β2M levels and follow-up outcomes.

RESULTS

Our results indicated that the β2M level of the good outcome (2.35 ± 0.84 mg/l) group was significantly lower than that of the poor outcome group (3.06 ± 1.71 mg/l) (P < 0.001). Further multiple regression analysis showed that β2M was regarded as a risk factor that was closely associated with the poor outcome 3 months after ICH onset (odds ratio = 2.26, 95% confidence interval = 1.22-4.19, P = 0.009). Further correlation analysis revealed that β2M was significantly correlated with NIHSS scores (r = 0.187, P = 0.004) and follow-up mRS scores (r = 0.25, P < 0.001).

CONCLUSION

β2M was a risk factor for early outcome after ICH onset, and high β2M level was associated with short-time poor prognosis of ICH patients.

Mechanism and Regulation of Microglia Polarization in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is the most lethal subtype of stroke, but effective treatments are lacking, and neuroinflammation plays a key role in the pathogenesis. In the innate immune response to cerebral hemorrhage, microglia first appear around the injured tissue and are involved in the inflammatory cascade response. Microglia respond to acute brain injury by being activated and polarized to either a typical M1-like (pro-inflammatory) or an alternative M2-like (anti-inflammatory) phenotype. These two polarization states produce pro-inflammatory or anti-inflammatory. With the discovery of the molecular mechanisms and key signaling molecules related to the polarization of microglia in the brain, some targets that regulate the polarization of microglia to reduce the inflammatory response are considered a treatment for secondary brain tissue after ICH damage effective strategies. Therefore, how to promote the polarization of microglia to the M2 phenotype after ICH has become the focus of attention in recent years. This article reviews the mechanism of action of microglia’s M1 and M2 phenotypes in secondary brain injury after ICH. Moreover, it discusses compounds and natural pharmaceutical ingredients that can polarize the M1 to the M2 phenotype.

Activation of Nrf2 to Optimise Immune Responses to Intracerebral Haemorrhage

Haemorrhage into the brain parenchyma can be devastating. This manifests as spontaneous intracerebral haemorrhage (ICH) after head trauma, and in the context of vascular dementia. Randomised controlled trials have not reliably shown that haemostatic treatments aimed at limiting ICH haematoma expansion and surgical approaches to reducing haematoma volume are effective. Consequently, treatments to modulate the pathophysiological responses to ICH, which may cause secondary brain injury, are appealing. Following ICH, microglia and monocyte derived cells are recruited to the peri-haematomal environment where they phagocytose haematoma breakdown products and secrete inflammatory cytokines, which may trigger both protective and harmful responses. The transcription factor Nrf2, is activated by oxidative stress, is highly expressed by central nervous system microglia and macroglia. When active, Nrf2 induces a transcriptional programme characterised by increased expression of antioxidant, haem and heavy metal detoxification and proteostasis genes, as well as suppression of proinflammatory factors. Therefore, Nrf2 activation may facilitate adaptive-protective immune cell responses to ICH by boosting resistance to oxidative stress and heavy metal toxicity, whilst limiting harmful inflammatory signalling, which can contribute to further blood brain barrier dysfunction and cerebral oedema. In this review, we consider the responses of immune cells to ICH and how these might be modulated by Nrf2 activation. Finally, we propose potential therapeutic strategies to harness Nrf2 to improve the outcomes of patients with ICH.

Dexmedetomidine post-conditioning protects blood-brain barrier integrity by modulating microglia/macrophage polarization via inhibiting NF-κB signaling pathway in intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is one of the most devastating forms of stroke. Dexmedetomidine (DEX) has shown certain neuroprotective roles in ICH. Nevertheless, the details concerning the underlying molecular mechanism of DEX’s protective effects still need further elucidation. Herein, a model of ICH was established. The rats were randomly divided into the sham group, the ICH group, and the ICH + DEX group. Neurological outcomes, neuronal injury, and apoptosis were evaluated. Brain water content, Evans blue extravasation, and the expression of tight junction-associated proteins were also detected to assess the blood-brain barrier (BBB) integrity. Subsequently, the microglia/macrophage polarization state and inflammatory cytokine levels were observed. To further explore the underlying mechanism, NF-κB signaling pathway-associated proteins were detected. The results showed that DEX exerted neuroprotective effects against ICH-induced neurological deficits. DEX significantly increased the numbers of the surviving neurons and ameliorated neuronal cell loss and apoptosis in ICH. The rats that received the DEX displayed a lower level of brain water content and EB extravasation, moreover, ZO-1, occludin, and claudin-5 were markedly increased by DEX. Additionally, DEX facilitated M2 microglia/macrophage polarization, the M1-associated markers were reduced by DEX, while the M2-associated identification significantly increased. We found that DEX dramatically diminished pro-inflammatory cytokines expression, simultaneously promoting anti-inflammatory cytokines expression. DEX inhibited nuclear translocation of NF-κB in ICH rats. Our data suggest that DEX post-conditioning protects BBB integrity by modulating microglia/macrophage polarization via inhibiting the NF-κB signaling pathway in ICH.

Temporal brain transcriptome analysis reveals key pathological events after germinal matrix hemorrhage in neonatal rats

Germinal matrix hemorrhage (GMH) is a common complication in preterm infants and is associated with high risk of adverse neurodevelopmental outcomes. We used a rat GMH model and performed RNA sequencing to investigate the signaling pathways and biological processes following hemorrhage. GMH induced brain injury characterized by early hematoma and subsequent tissue loss. At 6 hours after GMH, gene expression indicated an increase in mitochondrial activity such as ATP metabolism and oxidative phosphorylation along with upregulation of cytoprotective pathways and heme metabolism. At 24 hours after GMH, the expression pattern suggested an increase in cell cycle progression and downregulation of neurodevelopmental-related pathways. At 72 hours after GMH, there was an increase in genes related to inflammation and an upregulation of ferroptosis. Hemoglobin components and genes related to heme metabolism and ferroptosis such as Hmox1, Alox15, and Alas2 were among the most upregulated genes. We observed dysregulation of processes involved in development, mitochondrial function, cholesterol biosynthesis, and inflammation, all of which contribute to neurodevelopmental deterioration following GMH. This study is the first temporal transcriptome profile providing a comprehensive overview of the molecular mechanisms underlying brain injury following GMH, and it provides useful guidance in the search for therapeutic interventions.

Development and Validation of a Clinical-Based Signature to Predict the 90-Day Functional Outcome for Spontaneous Intracerebral Hemorrhage

We aimed to develop and validate an objective and easy-to-use model for identifying patients with spontaneous intracerebral hemorrhage (ICH) who have a poor 90-day prognosis. This three-center retrospective study included a large cohort of 1,122 patients with ICH who presented within 6 h of symptom onset [training cohort, n = 835; internal validation cohort, n = 201; external validation cohort (center 2 and 3), n = 86]. We collected the patients’ baseline clinical, radiological, and laboratory data as well as the 90-day functional outcomes. Independent risk factors for prognosis were identified through univariate analysis and multivariate logistic regression analysis. A nomogram was developed to visualize the model results while a calibration curve was used to verify whether the predictive performance was satisfactorily consistent with the ideal curve. Finally, we used decision curves to assess the clinical utility of the model. At 90 days, 714 (63.6%) patients had a poor prognosis. Factors associated with prognosis included age, midline shift, intraventricular hemorrhage (IVH), subarachnoid hemorrhage (SAH), hypodensities, ICH volume, perihematomal edema (PHE) volume, temperature, systolic blood pressure, Glasgow Coma Scale (GCS) score, white blood cell (WBC), neutrophil, and neutrophil-lymphocyte ratio (NLR) (p < 0.05). Moreover, age, ICH volume, and GCS were identified as independent risk factors for prognosis. For identifying patients with poor prognosis, the model showed an area under the receiver operating characteristic curve of 0.874, 0.822, and 0.868 in the training cohort, internal validation, and external validation cohorts, respectively. The calibration curve revealed that the nomogram showed satisfactory calibration in the training and validation cohorts. Decision curve analysis showed the clinical utility of the nomogram. Taken together, the nomogram developed in this study could facilitate the individualized outcome prediction in patients with ICH.

Dysregulation of microRNA and Intracerebral Hemorrhage: Roles in Neuroinflammation

Intracerebral hemorrhage (ICH) is a major public health problem and devastating subtype of stroke with high morbidity and mortality. Notably, there is no effective treatment for ICH. Neuroinflammation, a pathological hallmark of ICH, contributes to both brain injury and repair and hence, it is regarded as a potential target for therapeutic intervention. Recent studies document that microRNAs, small non-coding RNA molecules, can regulate inflammatory brain response after ICH and are viable molecular targets to alter brain function. Therefore, there is an escalating interest in studying the role of microRNAs in the pathophysiology of ICH. Herein, we provide, for the first time, an overview of the microRNAs that play roles in ICH-induced neuroinflammation and identify the critical knowledge gap in the field, as it would help design future studies.

Puerarin attenuates intracerebral hemorrhage-induced early brain injury possibly by PI3K/Akt signal activation-mediated suppression of NF-κB pathway

Intracerebral hemorrhage (ICH) can induce intensively oxidative stress, neuroinflammation, and brain cell apoptosis. However, currently, there is no highly effective treatment available. Puerarin (PUE) possesses excellent neuroprotective effects by suppressing the NF‐κB pathway and activating the PI3K/Akt signal, but its role and related mechanisms in ICH‐induced early brain injury (EBI) remain unclear. In this study, we intended to observe the effects of PUE and molecular mechanisms on ICH‐induced EBI. ICH was induced in rats by collagenase IV injection. PUE was intraperitoneally administrated alone or with simultaneously intracerebroventricular injection of LY294002 (a specific inhibitor of the PI3K/Akt signal). Neurological deficiency, histological impairment, brain edema, hematoma volume, blood–brain barrier destruction, and brain cell apoptosis were evaluated. Western blot, immunohistochemistry staining, reactive oxygen species (ROS) measurement, and enzyme‐linked immunosorbent assay were performed. PUE administration at 50 mg/kg and 100 mg/kg could significantly reduce ICH‐induced neurological deficits and EBI. Moreover, PUE could notably restrain ICH‐induced upregulation of the NF‐κB pathway, pro‐inflammatory cytokines, ROS level, and apoptotic pathway and activate the PI3K/Akt signal. However, LY294002 delivery could efficaciously weaken these neuroprotective effects of PUE. Overall, PUE could attenuate ICH‐induced behavioral defects and EBI possibly by PI3K/Akt signal stimulation‐mediated inhibition of the NF‐κB pathway, and this made PUE a potential candidate as a promising therapeutic option for ICH‐induced EBI.

A clinical-radiomics nomogram may provide a personalized 90-day functional outcome assessment for spontaneous intracerebral hemorrhage

OBJECTIVES

To develop and validate a noncontrast computed tomography (NCCT)-based clinical-radiomics nomogram to identify spontaneous intracerebral hemorrhage (sICH) patients with a poor 90-day prognosis on admission.

METHODS

In this double-center retrospective study, data from 435 patients with sICH (training cohort: n = 244; internal validation cohort: n = 104; external validation cohort: n = 87) were reviewed. The radiomics score (Rad-score) was calculated based on the coefficients of the selected radiomics features. A clinical-radiomics nomogram was developed by using independent predictors of poor outcome at 90 days through multivariate logistic regression analysis in the training cohort and was validated in the internal and external cohorts.

RESULTS

At 90 days, 200 of 435 (46.0%) patients had a poor prognosis. The clinical-radiomics nomogram was developed by six independent predictors namely midline shift, NCCT time from sICH onset, Glasgow Coma Scale score, serum glucose, uric acid, and Rad-score. In identifying patients with poor prognosis, the clinical-radiomics nomogram showed an area under the receiver operating characteristic curve (AUC) of 0.81 in the training cohort, an AUC of 0.78 in the internal validation cohort, and an AUC of 0.73 in the external validation cohort. The calibration curve revealed that the clinical-radiomics nomogram showed satisfactory calibration in the training and internal validation cohorts (both p > 0.05), but slightly poor agreement in the external validation cohort (p < 0.05).

CONCLUSIONS

The clinical-radiomics nomogram is a valid computer-aided tool that may provide personalized risk assessment of 90-day functional outcome for sICH patients.

KEY POINTS

• The proposed Rad-score was significantly associated with 90-day poor functional outcome in patients with sICH. • The clinical-radiomics nomogram showed satisfactory calibration and the most net benefit for discriminating 90-day poor outcome. • The clinical-radiomics nomogram may provide personalized risk assessment of 90-day functional outcome for sICH patients.

Modulation of Microglia Polarization through Silencing of NF-κB p65 by Functionalized Curdlan Nanoparticle-Mediated RNAi

Microglia polarization plays an important role in poststroke recovery. Inhibition of proinflammatory (M1) polarization and promotion of anti-inflammatory (M2) polarization of microglia are potential therapeutic strategies for inflammation reduction and neuronal recovery after stroke. Here, we evaluated the central nervous system (CNS)-targeted short interfering RNA (siRNA) delivery ability of functionalized curdlan nanoparticles (CMI) and investigated the nuclear factor-κB (NF-κB) p65 silencing efficiency of CMI-mediated siRNA in microglia, as well as the resulting neuroprotective effect of microglia polarization and neuroprotection in vitro and in vivo. The systemic delivery of NF-κB p65 siRNA (sip65) complexed to CMI nanoparticles in the mouse model of transient middle cerebral artery occlusion (tMCAO) resulted in the distribution of siRNA in microglia and significant silencing in NF-κB p65 in the peri-infarct region. Knockdown of NF-κB p65 resulted in M1 to M2 phenotypic transition of microglia, evidenced by the change in the expression pattern of signature cytokines as well as inducible nitric oxide synthase and CD206. Moreover, the CMI-mediated silencing of p65 increased the density of neurons and decreased pyknosis and edema in the peri-infarct region. Assessment of the neurological deficit score on the Bederson scale revealed a significantly reduced score in the mouse model of tMCAO treated with the sip65/CMI complex. Collectively, our data suggest that CMI nanoparticles are a promising CNS-targeting siRNA delivery system, and NF-κB p65 may be a potential therapeutic target for inflammation reduction and poststroke recovery.

Inhibiting nuclear factor-κB at different stages after intracerebral hemorrhage can influence the hemorrhage-induced brain injury in experimental models in vivo

OBJECTIVE

Nuclear factor-κB (NF-κB) is a critical regulator of inflammatory responses after ICH, and different subunits may have different influences on the cell death and prognosis. The aim of the present study is to clarify whether the prognosis can be influenced by inhibiting NF-κB activation and subunits expression using PDTC at different stages after ICH.

METHODS

Rats were divided into sham group, ICH group, early interference group and late interference group. At preset time points after ICH, the ipsilateral striatum and tissue around was obtained for detection of NF-κB activation, cell death, and expression of caspase-3, bcl-2, and NF-κB subunits, to evaluate of the effect of PDTC.

RESULTS

NF-κB subunit p65 mainly expressed at the early stage after ICH, and c-Rel at the late stage. NF-κB activation can be inhibited at the early stage after ICH by administrating PDTC at 10 min, 1d and 2d after ICH, and at the late stage at 6d,7d and 8d. NF-κB activation inhibition at the early stage was due to p65, and c-Rel at the late stage. Inhibiting p65 expression at the early stage after ICH can reduce the apoptotic factor caspase-3 expression and cell death, and raise the antiapoptotic factor bcl-2. Meanwhile, inhibiting c-Rel expression at the late stage after ICH can lead to the opposite result.

CONCLUSION

Measures of inhibiting NF-κB subunits can be performed to influence the secondary brain damage and prognosis of ICH. We can also speculate that early inhibition of p65 expression and late promotion of c-Rel expression may be a more efficient method to improve the prognosis of ICH.

NEMO-binding domain peptides alleviate perihematomal inflammation injury after experimental intracerebral hemorrhage

Inflammation aggravates the lethal consequences of intracerebral hemorrhage. Recently, many studies have found that nuclear factor-κB (NF-κB) is a crucial transcription factor that initiates inflammation in the perihematomal region of ICH. NF-κB essential modulator (NEMO)-binding domain (NBD) peptide, a cell-permeable peptide spanning the NBD of IKKα or IKKβ, functions as a highly specific inhibitor of NF-κB. This peptide can negatively regulate the NF-κB pathway. The present study aimed to explore the effects and underlying pathomechanisms of NBD peptides after ICH. Striatum infusion of whole blood or saline was performed on C57BL/6 mice (n = 198). Experimental animals were administered NBD or control (mutated) peptides 2 h before or after ICH by intracerebroventricular injection (icv.). NBD peptides significantly inhibited edema formation, ameliorated the neurological deficits, markedly reduced IκBα and p65 phosphorylation, blocked nuclear translocation of p65, and upregulated IκBα expression by NF-κB after ICH induction. Using an in vitro hemin toxicity model, we investigated the effects of NBD peptides on microglial inflammation. We found that NBD peptides suppressed microglia inflammation and lowered the expression of TNF-α and IL-1β in both in vivo and in vitro experiments. Further experiments were performed in mice and cultured microglia, which treated with NBD peptides in the presence of p65 siRNA confirmed that the specificity of NBD peptides inhibit ICH-induced NF-κB activation. This study demonstrated that NBD peptides exert a neuroprotective role after ICH and might be a potential candidate for a novel therapeutic strategy for ICH.

Intracerebral Hemorrhage as an Axonal Tract Injury Disorder with Inflammatory Reactions

Intracerebral hemorrhage (ICH) is a neurological disorder frequently accompanied by severe dysfunction. Critical pathogenic events leading to poor prognosis should be identified for the development of novel effective therapies for ICH. Here we focus on the injury of the axonal tract, particularly of the internal capsule, with reference to its contribution to ICH pathology and potential therapeutic interventions in addition to its cellular mechanisms. Studies on human ICH patients and rodent models of ICH suggest that invasion of hematoma into the internal capsule greatly worsens the severity of post-ICH symptoms. A blood-derived protease thrombin may play an important role in the acute phase of axonal tract injury in the internal capsule that includes compromised axonal transport and fragmentation of axonal structures. Several agents such as clioquinol, melatonin and Am80 (a retinoic acid receptor agonist) have been shown to produce therapeutic effects on rodent models of ICH associated with injury of the internal capsule. In the course of examinations on the effect of Am80, we obtained evidence for the involvement of CXCL2, a neutrophil chemotactic factor, in the pathogenesis of ICH. Accordingly, we also refer to the potential roles of infiltrating neutrophils and inflammatory responses in axonal tract injury and resultant neurological dysfunction in ICH.

MicroRNA-27b inhibition promotes Nrf2/ARE pathway activation and alleviates intracerebral hemorrhage-induced brain injury

Oxidative stress and neuroinflammation are the key factors leading to secondary brain injury after intracerebral hemorrhage (ICH). We investigated the effects of miR-27b, an oxidative stress-responsive microRNA, on ICH-induced brain injury in rats. The ICH model was induced by intracerebral injection of collagenase. Following ICH, miR-27b expression in the striatum was reduced, whereas expression of Nrf2 mRNA and protein was increased. In PC12 cells, overexpression of miR-27b reduced expression of Nrf2, Hmox1, Sod1 and Nqo1, while miR-27b inhibition had the opposite effects. Dual luciferase reporter assays showed that Nrf2 mRNA was a direct target of miR-27b. Intracerebroventricular injection of miR-27b antagomir and transfection of miR-27b inhibitor inhibited endogenous miR-27b in rats and PC12 cells, respectively. MiR-27b antagomir promoted activation of the ICH-induced Nrf2/ARE pathway and reduced the lipid peroxidation, neuroinflammation, cell death and neurological deficits otherwise seen after ICH. In PC12 cells, the miR-27b inhibitor diminished iron-induced oxidative stress, inflammation and apoptosis, and those effects were blocked by Nrf2 knockdown. These results demonstrate that miR-27b inhibition alleviates ICH-induced brain injury, which may be explained in part by its regulation on the Nrf2/ARE pathway.

Modulators of microglial activation and polarization after intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is the most lethal subtype of stroke but currently lacks effective treatment. Microglia are among the first non-neuronal cells on the scene during the innate immune response to ICH. Microglia respond to acute brain injury by becoming activated and developing classic M1-like (proinflammatory) or alternative M2-like (anti-inflammatory) phenotypes. This polarization implies as yet unrecognized actions of microglia in ICH pathology and recovery, perhaps involving microglial production of proinflammatory or anti-inflammatory cytokines and chemokines. Furthermore, alternatively activated M2-like microglia might promote phagocytosis of red blood cells and tissue debris, a major contribution to haematoma clearance. Interactions between microglia and other cells modulate microglial activation and function, and are also important in ICH pathology. This Review summarizes key studies on modulators of microglial activation and polarization after ICH, including M1-like and M2-like microglial phenotype markers, transcription factors and key signalling pathways. Microglial phagocytosis, haematoma resolution, and the potential crosstalk between microglia and T lymphocytes, neurons, astrocytes, and oligodendrocytes in the ICH brain are described. Finally, the clinical and translational implications of microglial polarization in ICH are presented, including the evidence that therapeutic approaches aimed at modulating microglial function might mitigate ICH injury and improve brain repair.

Minimally invasive thalamic hematoma drainage can improve the six-month outcome of thalamic hemorrhage

Objective

To explore predictors of the 6-month clinical outcome of thalamic hemorrhage, and evaluate if minimally invasive thalamic hematoma drainage (THD) could improve its prognosis.

Methods

A total of 54 patients with spontaneous thalamic hemorrhage were evaluated retrospectively. Clinical data, including demographics, stroke risk factors, neuroimaging variables, Glasgow Coma Score (GCS) on admission, surgical strategy, and outcome, were collected. Clinical outcome was assessed using a modified Rankin Scale, six months after onset. Univariate analysis and multivariate logistic regression analysis were performed to determine predictors of a poor outcome.

Results

Conservative treatment was performed for five patients (9.3%), external ventricular drainage (EVD) for 20 patients (37.0%), THD for four patients (7.4%), and EVD combined with THD for 25 patients (46.3%). At six months after onset, 21 (38.9%) patients achieved a favorable outcome, while 33 (61.1%) had a poor outcome. In the univariate analysis, predictors of poor 6-month outcome were lower GCS on admission (P = 0.001), larger hematoma volume (P < 0.001), midline shift (P = 0.035), acute hydrocephalus (P = 0.039), and no THD (P = 0.037). The independent predictors of poor outcome, according to the multivariate logistic regression analysis, were no THD and larger hematoma volume.

Conclusions

Minimally invasive THD, which removes most of the hematoma within a few days, with limited damage to perihematomal brain tissue, improved the 6-month outcome of thalamic hemorrhage. Thus, THD can be widely applied to treat patients with thalamic hemorrhage.

Stereotactic Administration of Edaravone Ameliorates Collagenase-Induced Intracerebral Hemorrhage in Rat

Background

Edaravone is widely used for treating ischemic stroke, but it is not still confirmed in intracerebral hemorrhage (ICH) as an ideal medication targeting the brain parenchyma. We aimed to investigate the neuroprotective effects of stereotactic administration of edaravone (SI) into the brain parenchyma.

Methods

Intracerebral hemorrhage rat models were established by infusion of collagenase into the caudate nucleus. Neural functional recovery was assessed using modified neurological severity scores (mNSS). A comparative study of therapeutic effects between SI and intraperitoneal injection of edaravone (IP) involved in cerebral edema, blood–brain barrier (BBB) permeability, hematoma absorption, inflammatory response and neuronal apoptosis.

Results

Compared with IP, the mNSS was significantly (P < 0.05) improved by SI; cerebral edema and BBB permeability were dramatically ameliorated (P < 0.05); IL‐4 and IL‐10 levels increased, but IL‐1β and TNF‐α levels significantly decreased; neuron apoptosis decreased markedly (P < 0.05); and caspase‐3 and Bax expression significantly dropped, but Bcl‐2 increased in SI group (P < 0.05).

Conclusion

SI markedly improved neurological deficits in ICH rat models via antiinflammatory and antiapoptosis mechanisms and promoted M2‐type microglia differentiation. SI was effective in rats with collagenase‐induced ICH.

Treatment of Edema Associated With Intracerebral Hemorrhage

OPINION STATEMENT

Cerebral edema (i.e., "brain swelling") is a common complication following intracerebral hemorrhage (ICH) and is associated with worse clinical outcomes. Perihematomal edema (PHE) accumulates during the first 72 h after hemorrhage, and during this period, patients are at risk of clinical deterioration due to the resulting tissue shifts and brain herniation. First-line medical therapies for patients symptomatic of PHE include osmotic agents, such as mannitol in low- or high-dose bolus form, or boluses of hypertonic saline (HTS) at varied concentrations with or without subsequent continuous infusion. Decompressive craniectomy may be required for symptomatic edema refractory to osmotherapy. Other strategies that reduce PHE such as hypothermia and minimally invasive surgery have shown promise in pilot studies and are currently being evaluated in larger clinical trials. Ongoing basic, translational, and clinical research seek to better elucidate the pathophysiology of PHE to identify novel strategies to prevent edema formation as a next major advance in the treatment of ICH.