Modulating the Immune Response Towards a Neuroregenerative Peri-injury Milieu After Cerebral Hemorrhage

Long Noncoding RNA GAS5-Involved Progression of Neonatal Hydrocephalus and Inflammatory Responses

Intraventricular hemorrhage results in posthemorrhagic hydrocephalus (PHH). Neonatal hydrocephalus remains a challenging disease due to the high failure rate of all management strategies. We evaluated long noncoding RNA growth arrest-specific 5 (GAS5)-mediated network in neonatal hydrocephalus, providing a new direction for the treatment of hydrocephalus. The PHH model was constructed in neonatal rats after intracerebroventricular injection with GAS5, miR-325-3p, and chaperonin containing T-complex protein 1, subunit 8 (CCT8) plasmids, or oligonucleotides. Next, behavioral tests, measurement of serum inflammation, observation of brain tissue pathology, and calculation of hemoglobin and brain water contents were implemented. GAS5, miR-325-3p, and CCT8 expression, in combination with their interactions, was checked. As the results reported, collagenase infusion induced hydrocephalus, impairing neurological function, enhancing inflammation and neuronal apoptosis, and increasing hemoglobin and brain water contents. GAS5 and CCT8 were up-regulated, while miR-325-3p was down-regulated in hydrocephalic rats. Downregulating GAS5/CCT8 or upregulating miR-325-3p could inhibit inflammatory response and improve neurological function in young hydrocephalic rats. GAS5 promotes CCT8 expression through sponge adsorption of miR-325-3p. GAS5 silencing-mediated protections against hydrocephalus were counteracted by CCT8 overexpression. In summary, GAS5 aggravates neonatal hydrocephalus and inflammatory responses in a way of leasing miR-325-3p-involved regulation of CCT8.

Palmatine attenuates LPS-induced neuroinflammation through the PI3K/Akt/NF-κB pathway

To investigate the key molecular mechanisms of palmatine for the treatment of neuroinflammation through modulation of a pathway using molecular docking, molecular dynamics (MD) simulation combined with network pharmacology, and animal experiments. Five alkaloid components were obtained from the traditional Chinese medicine Huangteng through literature mining. Molecular docking and MD simulation with acetylcholinesterase were used to screen palmatine. At the animal level, mice were injected with LPS intracerebrally to cause a neuroinflammatory model, and the Morris water maze experiment was performed to examine the learning memory of mice. Anxiety levels were tested using the autonomous activity behavior experiment with the open field and elevated behavior experiments. HE staining and Niss staining were performed on brain tissue sections to observe morphological lesions and apoptosis; serum was examined for inflammatory factors TNF-α, IL-6, and IL-1β; Western blot was performed to detect the protein expression. The expression of PI3K/AKT/NFkB signaling pathway-related proteins was examined by Western blot. The results of network pharmacology showed that the screening of palmatine activation containing the PI3K/Akt/NFkB signaling pathway exerts antineuroinflammatory effects. Results from behavioral experiments showed that Pal enhanced learning memory in model mice, improved anxiety behavior, and significantly improved brain damage caused by neuroinflammation. The results of HE staining and Niss staining of brain tissue sections showed that palmatine could alleviate morphological lesions and nucleus damage in brain tissue. Palmatine improved the levels of serum inflammatory factors TNF-α, IL-6, and IL-1β. SOD, MDA, CAT, ACH, and ACHE in the hippocampus were improved. Western blot results showed that palmatine administration ameliorated LPS-induced neuroinflammation through the PI3K/Akt/NFkB pathway.

Ocimum sanctum [Tulsi] as a Potential Immunomodulator for the Treatment of Ischemic Injury in the Brain

Stroke causes brain damage and is one of the main reasons for death. Most survivors of stroke face long-term physical disabilities and cognitive dysfunctions. In addition, they also have persistent emotional and behavioral changes. The two main treatments that are effective are reperfusion with recombinant tissue plasminogen activator and recanalization of penumbra using mechanical thrombectomy. However, these treatments are suitable only for a few patients due to limitations such as susceptibility to hemorrhage and the requirement for administering tissue plasminogen activators within the short therapeutic window during the early hours following a stroke. The paucity of interventions and treatments could be because of the multiple pathological mechanisms induced in the brain by stroke. The ongoing immune response following stroke has been attributed to the worsening brain injury. Hence, novel compounds with immunomodulatory properties that could improve the outcome of stroke patients are required. Natural compounds and medicinal herbs with anti-inflammatory activities and having minimal or no adverse systemic effect could be beneficial in treating stroke. Ocimum sanctum is a medicinal herb that can be considered an effective therapeutic option for ischemic brain injury. Ocimum sanctum, commonly known as holy basil or "Tulsi," is mentioned as the "Elixir of Life" for its healing powers. Since antiquity, Tulsi has been used in the Ayurvedic and Siddha medical systems to treat several diseases. It possesses immuno-modulatory activity, which can alter cellular and humoral immune responses. Tulsi can be considered a potential option as an immuno-modulator for treating various diseases, including brain stroke. In this review, we will focus on the immunomodulatory properties of Tulsi, specifically its effect on both innate and adaptive immunity, as well as its antioxidant and antiinflammatory properties, which could potentially be effective in treating ongoing immune reactions following ischemic brain injury.

Recent advances in tissue repair of the blood-brain barrier after stroke

The selective permeability of the blood-brain barrier (BBB) enables the necessary exchange of substances between the brain parenchyma and circulating blood and is important for the normal functioning of the central nervous system. Ischemic stroke inflicts damage upon the BBB, triggering adverse stroke outcomes such as cerebral edema, hemorrhagic transformation, and aggravated neuroinflammation. Therefore, effective repair of the damaged BBB after stroke and neovascularization that allows for the unique selective transfer of substances from the BBB after stroke is necessary and important for the recovery of brain function. This review focuses on four important therapies that have effects of BBB tissue repair after stroke in the last seven years. Most of these new therapies show increased expression of BBB tight-junction proteins, and some show beneficial results in terms of enhanced pericyte coverage at the injured vessels. This review also briefly outlines three effective classes of approaches and their mechanisms for promoting neoangiogenesis following a stroke.

Mesenchymal stem cell-derived exosomes: Shaping the next era of stroke treatment

Exosome-based treatments are gaining traction as a viable approach to addressing the various issues faced by an ischemic stroke. These extracellular vesicles, mainly produced by Mesenchymal Stem Cells (MSCs), exhibit many properties with substantial therapeutic potential. Exosomes are particularly appealing for stroke therapy because of their low immunogenicity, effective cargo transport, and ability to cross the blood-brain barrier. Their diverse effects include neuroprotection, angiogenesis stimulation, inflammatory response modulation, and cell death pathway attenuation, synergistically promoting neuronal survival, tissue regeneration, and functional recovery. Exosomes also show potential as diagnostic indicators for early stroke identification and customized treatment options. Despite these promising qualities, current exosome-based therapeutics have some limitations. The heterogeneity of exosome release among cell types, difficulty in standardization and isolation techniques, and complications linked to dosage and targeted administration necessitates extensive investigation. It is critical to thoroughly understand exosomal processes and their complicated interactions within the cellular milieu. To improve the practicality and efficacy of exosome-based medicines, research efforts must focus on improving production processes, developing robust evaluation criteria, and developing large-scale isolation techniques. Altogether, exosomes' multifunctional properties offer a new route for transforming stroke treatment and significantly improving patient outcomes.

Regulatory T cells: A suppressor arm in post-stroke immune homeostasis

The activation of the immune system and the onset of pro- and anti-inflammatory responses play crucial roles in the pathophysiological processes of ischaemic stroke (IS). CD4+ regulatory T (Treg) cells is the main immunosuppressive cell population that is studied in the context of peripheral tolerance, autoimmunity, and the development of chronic inflammatory diseases. In recent years, more studies have focused on immune modulation after IS, and Treg cells have been demonstrated to be essential in the remission of inflammation, nerve regeneration, and behavioural recovery. However, the exact effects of Treg cells in the context of IS remain controversial, with some studies suggesting a negative correlation with stroke outcomes. In this review, we aim to provide a comprehensive overview of the current understanding of Treg cell involvement in post-stroke homeostasis. We summarized the literature focusing on the temporal changes in Treg cell populations after IS, the mechanisms of Treg cell-mediated immunomodulation in the brain, and the potential of Treg cell-based therapies for treatment. The purposes of the current article are to address the importance of Treg cells and inspire more studies to help physicians, as well as scientists, understand the whole map of immune responses during IS.

Recombinant Slit2 suppresses neuroinflammation and Cdc42-mediated brain infiltration of peripheral immune cells via Robo1-srGAP1 pathway in a rat model of germinal matrix hemorrhage

BACKGROUND

Germinal matrix hemorrhage (GMH) is a devastating neonatal stroke, in which neuroinflammation is a critical pathological contributor. Slit2, a secreted extracellular matrix protein, plays a repulsive role in axon guidance and leukocyte chemotaxis via the roundabout1 (Robo1) receptor. This study aimed to explore effects of recombinant Slit2 on neuroinflammation and the underlying mechanism in a rat model of GMH.

METHODS

GMH was induced by stereotactically infusing 0.3 U of bacterial collagenase into the germinal matrix of 7-day-old Sprague Dawley rats. Recombinant Slit2 or its vehicle was administered intranasally at 1 h after GMH and daily for 3 consecutive days. A decoy receptor recombinant Robo1 was co-administered with recombinant Slit2 after GMH. Slit2 siRNA, srGAP1 siRNA or the scrambled sequences were administered intracerebroventricularly 24 h before GMH. Neurobehavior, brain water content, Western blotting, immunofluorescence staining and Cdc42 activity assays were performed.

RESULTS

The endogenous brain Slit2 and Robo1 expressions were increased after GMH. Robo1 was expressed on neuron, astrocytes and infiltrated peripheral immune cells in the brain. Endogenous Slit2 knockdown by Slit2 siRNA exacerbated brain edema and neurological deficits following GMH. Recombinant Slit2 (rSlit2) reduced neurological deficits, proinflammatory cytokines, intercellular adhesion molecules, peripheral immune cell markers, neuronal apoptosis and Cdc42 activity in the brain tissue after GMH. The anti-neuroinflammation effects were reversed by recombinant Robo1 co-administration or srGAP1 siRNA.

CONCLUSIONS

Recombinant Slit2 reduced neuroinflammation and neuron apoptosis after GMH. Its anti-neuroinflammation effects by suppressing onCdc42-mediated brain peripheral immune cells infiltration was at least in part via Robo1-srGAP1 pathway. These results imply that recombinant Slit2 may have potentials as a therapeutic option for neonatal brain injuries.

Identification of disulfidptosis-related genes and analysis of immune infiltration characteristics in ischemic strokes

Immune infiltration plays a pivotal role in the pathogenesis of ischemic stroke. A novel form of cell death known as disulfidptosis has emerged in recent studies. However, there is currently a lack of research investigating the regulatory mechanism of disulfidptosis-related genes in immune infiltration during ischemic stroke. Using machine learning methods, we identified candidate key disulfidptosis-related genes (DRGs). Subsequently, we performed an analysis of immune cell infiltration to investigate the dysregulation of immune cells in the context of ischemic stroke. We assessed their diagnostic value by employing receiver operating characteristic (ROC) curves. To gain further insights, we conducted functional enrichment analyses to elucidate the signaling pathways associated with these seven DRGs. We identified two distinct subclusters based on the expression patterns of these seven DRGs. The unique roles of these subclusters were further evaluated through KEGG analysis and immune infiltration studies. Furthermore, we validated the expression profiles of these seven DRGs using both single-cell datasets and external datasets. Lastly, molecular docking was performed to explore potential drugs for the treatment of ischemic stroke. We identified seven DRGs. The seven DRGs are related to immune cells. Additionally, these seven DRGs also demonstrate potential diagnostic value in ischemic stroke. Functional enrichment analysis highlighted pathways such as platelet aggregation and platelet activation. Two subclusters related to disulfidptosis were defined, and functional enrichment analysis of their differentially expressed genes (DEGs) primarily involved pathways like cytokine-cytokine receptor interaction. Single-cell analysis indicated that these seven DRGs were primarily distributed among immune cell types. Molecular docking results suggested that genistein might be a potential therapeutic drug. This study has opened up new avenues for exploring the causes of ischemic stroke and developing potential therapeutic targets.

Hydrocephalus is an independent factor affecting morbidity and mortality of ICH patients: Systematic review and meta-analysis

Background

Despite advances in our knowledge of the causes, preventions, and treatments of stroke, it continues to be a leading cause of death and disability. The most common type of stroke-related morbidity and mortality is intracerebral haemorrhage (ICH). Many prognostication scores include an intraventricular extension (IVH) after ICH because it affects mortality independently. Although it is a direct result of IVH and results in significant damage, hydrocephalus (HC) has never been taken into account when calculating prognostication scores. This study aimed to evaluate the significance of hydrocephalus on the outcomes of ICH patients by meta-analysis.

Methods

Studies that compared the rates of mortality and/or morbidity in patients with ICH, ICH with IVH (ICH ​+ ​IVH), and ICH with IVH and HC (ICH ​+ ​IVH ​+ ​HC) were identified. A meta-analysis was performed by using Mantel-Haezel Risk Ratio at 95% significance.

Results

This meta-analysis included thirteen studies. The findings indicate that ICH ​+ ​IVH ​+ ​HC has higher long-term (90-day) and short-term (30-day) mortality risks than ICH (4.26 and 2.30 higher risks, respectively) and ICH ​+ ​IVH (1.96 and 1.54 higher risks). Patients with ICH ​+ ​IVH ​+ ​HC have lower rates of short-term (3 months) and long-term (6 months) good functional outcomes than those with ICH (0.66 and 0.38 times) or ICH ​+ ​IVH (0.76 and 0.54 times). Confounding variables included vascular comorbidities, haemorrhage volume, midline shift, and an initial GCS score below 8.

Conclusion

Hydrocephalus causes a poorer prognosis in ICH patients. Thus, it is reasonable to suggest the inclusion of hydrocephalus in ICH prognostication scoring systems.

Therapeutic strategies to recover ependymal barrier after inflammatory damage: relevance for recovering neurogenesis during development

The epithelium covering the surfaces of the cerebral ventricular system is known as the ependyma, and is essential for maintaining the physical and functional integrity of the central nervous system. Additionally, the ependyma plays an essential role in neurogenesis, neuroinflammatory modulation and neurodegenerative diseases. Ependyma barrier is severely affected by perinatal hemorrhages and infections that cross the blood brain barrier. The recovery and regeneration of ependyma after damage are key to stabilizing neuroinflammatory and neurodegenerative processes that are critical during early postnatal ages. Unfortunately, there are no effective therapies to regenerate this tissue in human patients. Here, the roles of the ependymal barrier in the context of neurogenesis and homeostasis are reviewed, and future research lines for development of actual therapeutic strategies are discussed.

The hallmark and crosstalk of immune cells after intracerebral hemorrhage: Immunotherapy perspectives

Intracerebral hemorrhage (ICH) is one of the most dangerous types of strokes with a high morbidity and mortality rate. Currently, the treatment of ICH is not well developed, mainly because its mechanisms are still unclear. Inflammation is one of the main types of secondary injury after ICH and catalyzes the adverse consequences of ICH. A large number of immune cells are involved in neuroinflammation, such as microglia, astrocytes, oligodendrocytes, lymphocytes, macrophages, and neutrophils. Nevertheless, the characteristics and crosstalk of immune cells have not been fully elucidated. In this review, we endeavor to delve into the respective characteristics of immune cells and their interactions in neuroimmune inflammation, and further elucidate favorable immunotherapeutic approaches regarding ICH, and finally present an outlook.

Neuroinflammation of microglia polarization in intracerebral hemorrhage and its potential targets for intervention

Microglia are the resident immune cells of the central nervous system (CNS) and play a key role in neurological diseases, including intracerebral hemorrhage (ICH). Microglia are activated to acquire either pro-inflammatory or anti-inflammatory phenotypes. After the onset of ICH, pro-inflammatory mediators produced by microglia at the early stages serve as a crucial character in neuroinflammation. Conversely, switching the microglial shift to an anti-inflammatory phenotype could alleviate inflammatory response and incite recovery. This review will elucidate the dynamic profiles of microglia phenotypes and their available shift following ICH. This study can facilitate an understanding of the self-regulatory functions of the immune system involving the shift of microglia phenotypes in ICH. Moreover, suggestions for future preclinical and clinical research and potential intervention strategies are discussed.

Effects of butyphthalide on microglia polarization after intracerebral hemorrhage and the underlying mechanisms

OBJECTIVES

Because intracerebral hemorrhage (ICH) has high morbidity, disability and mortality, it is significant to find new and effective treatments for ICH. This study aims to explore the effect of butyphthalide (NBP) on neuroinflammation secondary to ICH and microglia polarization.

METHODS

A total of 48 healthy male SD rats were randomly divided into 6 groups: a sham 24 h group, a sham 72 h group, an ICH 24 h group, an ICH 72 h group, an ICH+NBP 24 h group, and an ICH+NBP 72 h group (8 rats per group). After operation, the neurological deficiencies were assessed based on improved Garcia scores and corner test. The expressions of Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), aquaporin-4 (AQP4), zonula occludens-1 (ZO-1), occludin, CD68, CD86, and CD206 were observed by Western blotting. Inflammatory cytokines were detected by ELISA. The immunofluorescence was to detect the polarization of microglia.

RESULTS

1) Compared with the sham groups, the expression of TLR4 (24 h: P<0.05; 72 h: P<0.01), NF-κB (both P<0.01) and Nrf2 (both P<0.01) in the perihematoma of the ICH group was increased, leading to microglia activation (P<0.01). The expressions of IL-6 (24 h: P<0.05; 72 h: P<0.01) and TNF-α (both P<0.01), the pro-inflammatory cytokines were up-regulated, and the expression of anti-inflammatory cytokine IL-4 was down-regulated (both P<0.01). Besides, the expression of AQP4 was enhanced (both P<0.01). The protein level of tightly connected proteins (including ZO-1, occludin) was decreased (all P<0.01). The neurological function of the rats in the ICH group was impaired in the 2 time points (both P<0.01). 2) Compared with the sham group at 24 h and 72 h after the intervention of NBP, the expressions of TLR4 (both P<0.05) and NF-κB (both P<0.01) were significantly declined, and the expression of Nrf2 was further enhanced (both P<0.05) in the perihematoma of the ICH+NBP group. Furthermore, the expression of M1 microglia marker was inhibited (P<0.05), and the polarization of microglia to the M2 phenotype was promoted (P<0.01). 3) In terms of inflammation after ICH, the IL-4 expression in the ICH+NBP group was increased compared with the ICH group (24 h: P<0.05; 72 h: P<0.01); the expression of IL-6 was decreased significantly in the ICH+NBP 72 h group (P<0.01); the level of AQP4 was declined significantly in the ICH+NBP 24 h group (P<0.05), there was a downward trend in the 72-hour intervention group but without significant statistical difference. 4) Compared with the ICH group, the ZO-1 protein levels were increased (24 h: P<0.05; 72 h: P<0.01), and the symptoms of nerve defect were improved eventually (both P<0.05) in the ICH+NBP groups.

CONCLUSIONS

After ICH, the TLR4/NF-κB pathway is activated. The M1 microglia is up-regulated along with the release of detrimental cytokines, while the anti-inflammatory cytokines are down-regulated. The expression of AQP4 is increased, the tight junction proteins from the blood-brain barrier (BBB) is damaged, and the neurological function of rats is impaired. On the contrary, NBP may regulate microglia polarization to M2 phenotype and play a role in the neuroprotective effect mediated via inhibiting TLR4/NF-κB and enhancing Nrf2 pathways, which relieves the neuroinflammation, inhibits the expression of AQP4, repairs BBB, and improves neurological functional defects.

Microglia: The Hub of Intercellular Communication in Ischemic Stroke

Communication between microglia and other cells has recently been at the forefront of research in central nervous system (CNS) disease. In this review, we provide an overview of the neuroinflammation mediated by microglia, highlight recent studies of crosstalk between microglia and CNS resident and infiltrating cells in the context of ischemic stroke (IS), and discuss how these interactions affect the course of IS. The in-depth exploration of microglia-intercellular communication will be beneficial for therapeutic tools development and clinical translation for stroke control.

Mechanisms of neuroinflammation in hydrocephalus after intraventricular hemorrhage: a review

Intraventricular hemorrhage (IVH) is a significant cause of morbidity and mortality in both neonatal and adult populations. IVH not only causes immediate damage to surrounding structures by way of mass effect and elevated intracranial pressure; the subsequent inflammation causes additional brain injury and edema. Of those neonates who experience severe IVH, 25-30% will go on to develop post-hemorrhagic hydrocephalus (PHH). PHH places neonates and adults at risk for white matter injury, seizures, and death. Unfortunately, the molecular determinants of PHH are not well understood. Within the past decade an emphasis has been placed on neuroinflammation in IVH and PHH. More information has come to light regarding inflammation-induced fibrosis and cerebrospinal fluid hypersecretion in response to IVH. The aim of this review is to discuss the role of neuroinflammation involving clot-derived neuroinflammatory factors including hemoglobin/iron, peroxiredoxin-2 and thrombin, as well as macrophages/microglia, cytokines and complement in the development of PHH. Understanding the mechanisms of neuroinflammation after IVH may highlight potential novel therapeutic targets for PHH.

Lymphocyte-Related Immunomodulatory Therapy with Siponimod (BAF-312) Improves Outcomes in Mice with Acute Intracerebral Hemorrhage

Modulators of the sphingosine-1-phosphate receptor (S1PR) have been proposed as a promising strategy for treating stroke. However, the detailed mechanisms and the potential translational value of S1PR modulators for intracerebral hemorrhage (ICH) therapy warrant exploration. Using collagenase VII-S-induced ICH in the left striatum of mice, we investigated the effects of siponimod on cellular and molecular immunoinflammatory responses in the hemorrhagic brain in the presence or absence of anti-CD3 monoclonal antibodies (Abs). We also assessed the severity of short- and long-term brain injury and evaluated the efficacy of siponimod in long-term neurologic function. Siponimod treatment significantly decreased brain lesion volume and brain water content on day 3 and the volume of the residual lesion and brain atrophy on day 28. It also inhibited neuronal degeneration on day 3 and improved long-term neurologic function. These protective effects may be associated with a reduction in the expression of lymphotactin (XCL1) and T-helper 1 (Th1)-type cytokines (interleukin 1β and interferon-γ). It may also be associated with inhibition of neutrophil and lymphocyte infiltration and alleviation of T lymphocyte activation in perihematomal tissues on day 3. However, siponimod did not affect the infiltration of natural killer cells (NK) or the activation of CD3-negative immunocytes in perihematomal tissues. Furthermore, it did not influence the activation or proliferation of microglia or astrocytes around the hematoma on day 3. Siponimod appears to have a profound impact on infiltration and activation of T lymphocytes after ICH. The effects of neutralized anti-CD3 Abs-induced T-lymphocyte tolerance on siponimod immunomodulation further confirmed that siponimod alleviated the cellular and molecular Th1 response in the hemorrhagic brain. This study provides preclinical evidence that encourages future investigation of immunomodulators, including siponimod, which target the lymphocyte-related immunoinflammatory reaction in ICH therapy.

Regulatory T cells in ischemic stroke

Recent evidence shows that when ischemic stroke (IS) occurs, the BBB would be destructed, thereby promoting the immune cells to migrate into the brain, suggesting that the immune responses can play a vital role in the pathology of IS. As an essential subpopulation of immunosuppressive T cells, regulatory T (Treg) cells are involved in maintaining immune homeostasis and suppressing immune responses in the pathophysiological conditions of IS. During the past decades, the regulatory role of Treg cells has attracted the interest of numerous researchers. However, whether they are beneficial or detrimental to the outcomes of IS remains controversial. Moreover, Treg cells exert distinctive effects in the different stages of IS. Therefore, it is urgent to elucidate how Treg cells modulate the immune responses induced by IS. In this review, we describe how Treg cells fluctuate and play a role in the regulation of immune responses after IS in both experimental animals and humans, and summarize their biological functions and mechanisms in both CNS and periphery. We also discuss how Treg cells participate in poststroke inflammation and immunodepression and the potential of Treg cells as a novel therapeutic approach.

White matter injury but not germinal matrix hemorrhage induces elevated osteopontin expression in human preterm brains

Osteopontin (OPN) is a matricellular protein that mediates various physiological functions and is implicated in neuroinflammation, myelination, and perinatal brain injury. However, its expression in association with brain injury in preterm infants is unexplored. Here we examined the expression of OPN in postmortem brains of preterm infants and explored how this expression is affected in brain injury. We analyzed brain sections from cases with white matter injury (WMI) and cases with germinal matrix hemorrhage (GMH) and compared them to control cases having no brain injury. WMI cases displayed moderate to severe tissue injury in the periventricular and deep white matter that was accompanied by an increase of microglia with amoeboid morphology. Apart from visible hemorrhage in the germinal matrix, GMH cases displayed diffuse white matter injury in the periventricular and deep white matter. In non-injured preterm brains, OPN was expressed at low levels in microglia, astrocytes, and oligodendrocytes. OPN expression was significantly increased in regions with white matter injury in both WMI cases and GMH cases. The main cellular source of OPN in white matter injury areas was amoeboid microglia, although a significant increase was also observed in astrocytes in WMI cases. OPN was not expressed in the germinal matrix of any case, regardless of whether there was hemorrhage. In conclusion, preterm brain injury induces elevated OPN expression in microglia and astrocytes, and this increase is found in sites closely related to injury in the white matter regions but not with the hemorrhage site in the germinal matrix. Thus, it appears that OPN takes part in the inflammatory process in white matter injury in preterm infants, and these findings facilitate our understanding of OPN's role under both physiological and pathological conditions in the human brain that may lead to greater elucidation of disease mechanisms and potentially better treatment strategies.

Delayed diapedesis of CD8 T cells contributes to long-term pathology after ischemic stroke in male mice

OBJECTIVE

Stroke is a debilitating disorder with significant annual mortality and morbidity rates worldwide. Immune cells are recruited to the injured brain within hours after stroke onset and can exhibit either protective or detrimental effects on recovery. However, immune cells, including CD8 T cells, persist in the injured brain for weeks, suggesting a longer-term role for the adaptive immune system during functional recovery. The aim of this study was to determine if the delayed secondary diapedesis of CD8 T cells into the ischemic brain negatively impacts functional recovery after transient ischemic stroke in male mice.

RESULTS

Mice exhibited an increased number of leukocytes in the ipsilesional hemispheres at 14 days (3-fold; p < 0.001) and 30 days (2.2-fold; p = 0.02) after transient middle cerebral artery occlusion (tMCAo) compared to 8 days post-tMCAo, at which time acute neuroinflammation predominantly resolves. Moreover, mice with higher ipsilesional CD8 T cells at 30 days (R² = 0.52, p < 0.01) exhibited worse functional recovery. To confirm a detrimental role of chronic CD8 T cell diapedesis on recovery, peripheral CD8 T cells were depleted beginning 10 days post-tMCAo. Delayed CD8 T cell depletion improved motor recovery on the rotarod (F_(1,28) = 4.264; p = 0.048) compared to isotype control-treated mice. CD8 T cell-depleted mice also exhibited 2-fold (p < 0.001) reduced leukocyte infiltration at 30 days post-tMCAo. Specifically, macrophage, neutrophil, and CD4 T cell numbers were reduced in the ipsilesional hemisphere of the CD8 T cell-depleted mice independent of inflammatory status of the post-stroke CNS (e.g. microglial phenotype and cytokine production). RNAseq identified a unique profile for brain infiltrating CD8 T cells at 30 days post-tMCAo, with 46 genes differentially expressed relative to CD8 T cells at 3 days post-tMCAo.

CONCLUSION

Our data reveal a role for CD8 T cells in the chronic phase post-stroke that can be therapeutically targeted. We demonstrate long-term CD8 T cell recruitment into the ipsilesional hemisphere that affects both immune cell numbers present in the injured brain and functional recovery through one month after stroke onset.

Immune Response in Neurological Pathology: Emerging Role of Central and Peripheral Immune Crosstalk

Neuroinflammation is a key component of neurological disorders and is an important therapeutic target; however, immunotherapies have been largely unsuccessful. In cases where these therapies have succeeded, particularly multiple sclerosis, they have primarily focused on one aspect of the disease and leave room for improvement. More recently, the impact of the peripheral immune system is being recognized, since it has become evident that the central nervous system is not immune-privileged, as once thought. In this review, we highlight key interactions between central and peripheral immune cells in neurological disorders. While traditional approaches have examined these systems separately, the immune responses and processes in neurological disorders consist of substantial crosstalk between cells of the central and peripheral immune systems. Here, we provide an overview of major immune effector cells and the role of the blood-brain barrier in regard to neurological disorders and provide examples of this crosstalk in various disorders, including stroke and traumatic brain injury, multiple sclerosis, neurodegenerative diseases, and brain cancer. Finally, we propose targeting central-peripheral immune interactions as a potential improved therapeutic strategy to overcome failures in clinical translation.

The immune response of T cells and therapeutic targets related to regulating the levels of T helper cells after ischaemic stroke

Through considerable effort in research and clinical studies, the immune system has been identified as a participant in the onset and progression of brain injury after ischaemic stroke. Due to the involvement of all types of immune cells, the roles of the immune system in stroke pathology and associated effects are complicated. Past research concentrated on the functions of monocytes and neutrophils in the pathogenesis of ischaemic stroke and tried to demonstrate the mechanisms of tissue injury and protection involving these immune cells. Within the past several years, an increasing number of studies have elucidated the vital functions of T cells in the innate and adaptive immune responses in both the acute and chronic phases of ischaemic stroke. Recently, the phenotypes of T cells with proinflammatory or anti-inflammatory function have been demonstrated in detail. T cells with distinctive phenotypes can also influence cerebral inflammation through various pathways, such as regulating the immune response, interacting with brain-resident immune cells and modulating neurogenesis and angiogenesis during different phases following stroke. In view of the limited treatment options available following stroke other than tissue plasminogen activator therapy, understanding the function of immune responses, especially T cell responses, in the post-stroke recovery period can provide a new therapeutic direction. Here, we discuss the different functions and temporal evolution of T cells with different phenotypes during the acute and chronic phases of ischaemic stroke. We suggest that modulating the balance between the proinflammatory and anti-inflammatory functions of T cells with distinct phenotypes may become a potential therapeutic approach that reduces the mortality and improves the functional outcomes and prognosis of patients suffering from ischaemic stroke.

Germinal Matrix-Intraventricular Hemorrhage of the Preterm Newborn and Preclinical Models: Inflammatory Considerations

The germinal matrix-intraventricular hemorrhage (GM-IVH) is one of the most important complications of the preterm newborn. Since these children are born at a critical time in brain development, they can develop short and long term neurological, sensory, cognitive and motor disabilities depending on the severity of the GM-IVH. In addition, hemorrhage triggers a microglia-mediated inflammatory response that damages the tissue adjacent to the injury. Nevertheless, a neuroprotective and neuroreparative role of the microglia has also been described, suggesting that neonatal microglia may have unique functions. While the implication of the inflammatory process in GM-IVH is well established, the difficulty to access a very delicate population has lead to the development of animal models that resemble the pathological features of GM-IVH. Genetically modified models and lesions induced by local administration of glycerol, collagenase or blood have been used to study associated inflammatory mechanisms as well as therapeutic targets. In the present study we review the GM-IVH complications, with special interest in inflammatory response and the role of microglia, both in patients and animal models, and we analyze specific proteins and cytokines that are currently under study as feasible predictors of GM-IVH evolution and prognosis.

Clinical nursing pathway improves the nursing satisfaction in patients with acute cerebral hemorrhage: A randomized controlled trial protocol

BACKGROUND

Cerebral hemorrhage (CH) is a very common cerebrovascular disorder in clinical practice. More and more studies reported that proper nursing care could promote the rate of treatment, and improve the prognosis after treatment. Clinical nursing pathway (CNP) refers to original nursing mode with good quality, outstanding efficiency, and low treatment spending. Few articles have reported the effect of CNP in patients with acute CH. The program is in urgent need of convinced evidence to prove the reliability. Thus, we perform this randomized controlled trial protocol and hypothesize that CNP is associated with improved outcomes and nursing satisfaction, reduced adverse reactions in patients with acute CH.

METHOD

It is a single-center randomized controlled study to be conducted from October 2020 to October 2021. It was admitted via the Ethics Committee of the West China Hospital of Sichuan University (0038842/121). Eighty patients meet diagnostic standards for CH are included. The study group receives the clinical nursing path model. In the control group, patients receive the routine care before and after taking to the hospital. The main outcome contains the Barthel index score, the patient's degree of satisfaction about care, the length of hospital stay, and the risk of complications such as infection, bedsores and gastrointestinal function between the 2 groups. Six months after admission, the functional independence measure and Fugl Meyer score are recorded. All data are analyzed by the IBM SPSS Statistics, version 20 (IBM Corp., Armonk, NY edition).

RESULTS

Table 1 shows the clinical outcomes between groups.

CONCLUSION

CNP may improve the clinical outcomes for patients with acute CH and have a significant value in actual applications.

TRIAL REGISTRATION NUMBER

researchregistry6061.

Galectin-9 Promotes Neuronal Restoration via Binding TLR-4 in a Rat Intracerebral Hemorrhage Model

Intracerebral hemorrhage (ICH) is a devastating disease with high rates of mortality and morbidity. Galactose lectin-9 (Gal-9) belongs to the family of β-galactoside-binding lectins, which has been shown to play a vital role in immune tolerance and inflammation. However, the function of Gal-9 in ICH has not been fully studied in details. Several experiments were carried out to explore the role of Gal-9 in the late period of ICH. Primarily, ICH models were established in male adult Sprague Dawley (SD) rats. Next, the relative protein levels of Gal-9 at different time points after ICH were examined and the result showed that the level of Gal-9 increased and peaked at the 7th day after ICH. Then we found that when the content of Gal-9 increased, both the number of M2-type microglia and the corresponding anti-inflammatory factors also increased. Through co-immunoprecipitation (CO-IP) analysis, it was found that Gal-9 combines with Toll-like receptor-4 (TLR-4) during the period of the recovery after ICH. TUNEL staining and Fluoro-Jade B staining (FJB) proved that the amount of cell death decreased with the increase of Gal-9 content. Additionally, several behavioral experiments also demonstrated that when the level of Gal-9 increased, the motor, sensory, learning, and memory abilities of the rats recovered better compared to the ICH group. In short, this study illustrated that Gal-9 takes a crucial role after ICH. Enhancing Gal-9 could alleviate brain injury and promote the recovery of ICH-induced injury, so that Gal-9 may exploit a new pathway for clinical treatment of ICH.

Neuroinflammation after Intracerebral Hemorrhage and Potential Therapeutic Targets

Spontaneous intracerebral hemorrhage (ICH) is a catastrophic illness causing significant morbidity and mortality. Despite advances in surgical technique addressing primary brain injury caused by ICH, little progress has been made treating the subsequent inflammatory cascade. Pre-clinical studies have made advancements identifying components of neuroinflammation, including microglia, astrocytes, and T lymphocytes. After cerebral insult, inflammation is initially driven by the M1 microglia, secreting cytokines (e.g., interleukin-1β [IL-1β] and tumor necrosis factor-α) that are involved in the breakdown of the extracellular matrix, cellular integrity, and the blood brain barrier. Additionally, inflammatory factors recruit and induce differentiation of A1 reactive astrocytes and T helper 1 (Th1) cells, which contribute to the secretion of inflammatory cytokines, augmenting M1 polarization and potentiating inflammation. Within 7 days of ICH ictus, the M1 phenotype coverts to a M2 phenotype, key for hematoma removal, tissue healing, and overall resolution of inflammation. The secretion of anti-inflammatory cytokines (e.g., IL-4, IL-10) can drive Th2 cell differentiation. M2 polarization is maintained by the secretion of additional anti-inflammatory cytokines by the Th2 cells, suppressing M1 and Th1 phenotypes. Elucidating the timing and trigger of the anti-inflammatory phenotype may be integral in improving clinical outcomes. A challenge in current translational research is the absence of an equivalent disease animal model mirroring the patient population and comorbid pathophysiologic state. We review existing data and describe potential therapeutic targets around which we are creating a bench to bedside translational research model that better reflects the pathophysiology of ICH patients.

Microglia and macrophage phenotypes in intracerebral haemorrhage injury: therapeutic opportunities

The prognosis of intracerebral haemorrhage continues to be devastating despite much research into this condition. A prominent feature of intracerebral haemorrhage is neuroinflammation, particularly the excessive representation of pro-inflammatory CNS-intrinsic microglia and monocyte-derived macrophages that infiltrate from the circulation. The pro-inflammatory microglia/macrophages produce injury-enhancing factors, including inflammatory cytokines, matrix metalloproteinases and reactive oxygen species. Conversely, the regulatory microglia/macrophages with potential reparative and anti-inflammatory roles are outcompeted in the early stages after intracerebral haemorrhage, and their beneficial roles appear to be overwhelmed by pro-inflammatory microglia/macrophages. In this review, we describe the activation of microglia/macrophages following intracerebral haemorrhage in animal models and clinical subjects, and consider their multiple mechanisms of cellular injury after haemorrhage. We review strategies and medications aimed at suppressing the pro-inflammatory activities of microglia/macrophages, and those directed at elevating the regulatory properties of these myeloid cells after intracerebral haemorrhage. We consider the translational potential of these medications from preclinical models to clinical use after intracerebral haemorrhage injury, and suggest that several approaches still lack the experimental support necessary for use in humans. Nonetheless, the preclinical data support the use of deactivator or inhibitor of pro-inflammatory microglia/macrophages, whilst enhancing the regulatory phenotype, as part of the therapeutic approach to improve the prognosis of intracerebral haemorrhage.

Posthemorrhagic hydrocephalus development after germinal matrix hemorrhage: Established mechanisms and proposed pathways

In addition to being the leading cause of morbidity and mortality in premature infants, germinal matrix hemorrhage (GMH) is also the leading cause of acquired infantile hydrocephalus. The pathophysiology of posthemorrhagic hydrocephalus (PHH) development after GMH is complex and vaguely understood, although evidence suggests fibrosis and gliosis in the periventricular and subarachnoid spaces disrupts normal cerebrospinal fluid (CSF) dynamics. Theories explaining general hydrocephalus etiology have substantially evolved from the original bulk flow theory developed by Dr. Dandy over a century ago. Current clinical and experimental evidence supports a new hydrodynamic theory for hydrocephalus development involving redistribution of vascular pulsations and disruption of Starling forces in the brain microcirculation. In this review, we discuss CSF flow dynamics, history and development of theoretical hydrocephalus pathophysiology, and GMH epidemiology and etiology as it relates to PHH development. We highlight known mechanisms and propose new avenues that will further elucidate GMH pathophysiology, specifically related to hydrocephalus.

Identification of hub genes and small-molecule compounds related to intracerebral hemorrhage with bioinformatics analysis

Background

Because of the complex mechanisms of injury, conventional surgical treatment and early blood pressure control does not significantly reduce mortality or improve patient prognosis in cases of intracerebral hemorrhage (ICH). We aimed to identify the hub genes associated with intracerebral hemorrhage, to act as therapeutic targets, and to identify potential small-molecule compounds for treating ICH.

Methods

The GSE24265 dataset, consisting of data from four perihematomal brain tissues and seven contralateral brain tissues, was downloaded from the Gene Expression Omnibus (GEO) database and screened for differentially expressed genes (DEGs) in ICH, with a fold change (FC) value of (|log2FC|) > 2 and a P-value of <0.05 set as cut-offs. The functional annotation of DEGs was performed using Gene Ontology (GO) resources, and the cell signaling pathway analysis of DEGs was performed using the Kyoto Encyclopedia of Genes and Genomes (KEGG), with a P-value of <0.05 set as the cut-off. We constructed a protein-protein interaction (PPI) network to clarify the interrelationships between the different DEGs and to select the hub genes with significant interactions. Next, the DEGs were analyzed using the CMap tool to identify small-molecule compounds with potential therapeutic effects. Finally, we verified the expression levels of the hub genes by RT-qPCR on the rat ICH model.

Result

A total of 59 up-regulated genes and eight down-regulated genes associated with ICH were identified. The biological functions of DEGs associated with ICH are mainly involved in the inflammatory response, chemokine activity, and immune response. The KEGG analysis identified several pathways significantly associated with ICH, including but not limited to HIF-1, TNF, toll-like receptor, cytokine-cytokine receptor interaction, and chemokine molecules. A PPI network consisting of 57 nodes and 373 edges was constructed using STRING, and 10 hub genes were identified with Cytoscape software. These hub genes are closely related to secondary brain injury induced by ICH. RT-qPCR results showed that the expression of ten hub genes was significantly increased in the rat model of ICH. In addition, a CMap analysis of three small-molecule compounds revealed their therapeutic potential.

Conclusion

In this study we obtained ten hub genes, such as IL6, TLR2, CXCL1, TIMP1, PLAUR, SERPINE1, SELE, CCL4, CCL20, and CD163, which play an important role in the pathology of ICH. At the same time, the ten hub genes obtained through PPI network analysis were verified in the rat model of ICH. In addition, we obtained three small molecule compounds that will have therapeutic effects on ICH, including Hecogenin, Lidocaine, and NU-1025.

Efficacy of microsurgery for patients with cerebral hemorrhage secondary to gestational hypertension: A systematic review protocol of randomized controlled trial

BACKGROUND

Microsurgery is widely utilized for patients with cerebral hemorrhage (CH). The purpose of this study is to assess the efficacy and safety of microsurgery for the treatment of patients with CH secondary to gestational hypertension (GH).

METHODS

Relevant randomized controlled trials in eight electronic databases of Cochrane Library, PUBMED, EMBASE, Web of Science, VIP, WANFANG, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure will be included. All electronic databases will be searched from inceptions to the present without language restriction. RevMan 5.3 software will be applied for statistical analysis.

RESULTS

This study will summarize a high-quality synthesis of maternal mortality, severe maternal complications, maternal quality of life, limbs function, muscle strength, and muscle tone to evaluate the efficacy and safety of microsurgery for patients with CH secondary to GH.

CONCLUSIONS

This study will provide evidence that microsurgery is an effective intervention in patients with CH secondary to GH.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019145750.

Rehabilitation training combined acupuncture for limb hemiplegia caused by cerebral hemorrhage: A protocol for a systematic review of randomized controlled trial

BACKGROUND

Previous studies have reported that rehabilitation training combined acupuncture (RTA) can be used for the treatment of limb hemiplegia (LH) caused by cerebral hemorrhage (CH). However, its effectiveness is still unclear. In this systematic review study, we aim to evaluate the effectiveness and safety of RTA for LH following CH.

METHODS

We will retrieve the databases of CENTRAL, EMBASE, MEDILINE, CINAHL, AMED, CBM, and CNKI from inception to March 1, 2019 with no language restrictions. The randomized controlled trials of RTA for evaluating effectiveness and safety in patients with LH following CH will be included. Cochrane risk of bias tool will be used to measure the methodological quality for all included studies. Two authors will independently select the studies, extract the data, and assess the methodological quality of included studies. A third author will be invited to discuss if any disagreements exist between 2 authors. If more than 2 eligible studies will be included, the outcome data will be pooled, and meta-analysis will be conducted if it is possible.

RESULTS

This systematic review will assess the effectiveness and safety of RTA for LH caused by CH. The primary outcome includes limbs function. The secondary outcomes consist of muscle strength, muscle tone, quality of life, and any adverse events.

CONCLUSION

The findings of this study will summarize the current evidence of RTA for LH caused by CH, and may provide helpful evidence for the clinical treatment.

DISSEMINATION AND ETHICS

The results of this study will be published in peer-reviewed journals or will be presented on conference meeting. This work does not require ethic approval, because it will be conducted based on the published studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019120034.

A comprehensive review of therapeutic targets that induce microglia/macrophage-mediated hematoma resolution after germinal matrix hemorrhage

Currently, there is no effective treatment for germinal matrix hemorrhage and intraventricular hemorrhage (GMH-IVH), a common and often fatal stroke subtype in premature infants. Secondary brain injury after GMH-IVH is known to involve blood clots that contribute to inflammation and neurological deficits. Furthermore, the subsequent blood clots disrupt normal cerebrospinal fluid circulation and absorption after GMH-IVH, contributing to posthemorrhagic hydrocephalus (PHH). Clinically, GMH-IVH severity is graded on a I to IV scale: Grade I is confined to the germinal matrix, grade II includes intraventricular hemorrhage, grade III includes intraventricular hemorrhage with extension into dilated ventricles, and grade IV includes intraventricular hemorrhage with extension into dilated ventricles as well as parenchymal hemorrhaging. GMH-IVH hematoma volume is the best prognostic indicator, where patients with higher grades have worsened outcomes. Various preclinical studies have shown that rapid hematoma resolution quickly ameliorates inflammation and improves neurological outcomes. Current experimental evidence identifies alternatively activated microglia as playing a pivotal role in hematoma clearance. In this review, we discuss the pathophysiology of GMH-IVH in the development of PHH, microglia/macrophage's role in the neonatal CNS, and established/potential therapeutic targets that enhance M2 microglia/macrophage phagocytosis of blood clots after GMH-IVH.

The peripheral immune response after stroke-A double edge sword for blood-brain barrier integrity

The blood‐brain barrier (BBB) is a highly regulated interface that separates the peripheral circulation and the brain. It plays a vital role in regulating the trafficking of solutes, fluid, and cells at the blood‐brain interface and maintaining the homeostasis of brain microenvironment for normal neuronal activity. Growing evidence has led to the realization that ischemic stroke elicits profound immune responses in the circulation and the activation of multiple subsets of immune cells, which in turn affect both the early disruption and the later repair of the BBB after stroke. Distinct phenotypes or subsets of peripheral immune cells along with diverse intracellular mechanisms contribute to the dynamic changes of BBB integrity after stroke. This review focuses on the interaction between the peripheral immune cells and the BBB after ischemic stroke. Understanding their reciprocal interaction may generate new directions for stroke research and may also drive the innovation of easy accessible immune modulatory treatment strategies targeting BBB in the pursuit of better stroke recovery.

Research Advances of Germinal Matrix Hemorrhage: An Update Review

Germinal matrix hemorrhage (GMH) refers to bleeding that derives from the subependymal (or periventricular) germinal region of the premature brain. GMH can induce severe and irreversible damage attributing to the vulnerable structure of germinal matrix and deleterious circumstances. Molecular mechanisms remain obscure so far. In this review, we summarized the newest preclinical discoveries recent years about GMH to distill a deeper understanding of the neuropathology, and then discuss the potential diagnostic or therapeutic targets among these pathways. GMH studies mostly in recent 5 years were sorted out and the authors generalized the newest discoveries and ideas into four parts of this essay. Intrinsic fragile structure of preterm germinal matrix is the fundamental cause leading to GMH. Many molecules have been found effective in the pathophysiological courses. Some of these molecules like minocycline are suggested active to reduce the damage in animal GMH model. However, researchers are still trying to find efficient diagnostic methods and remedies that are available in preterm infants to rehabilitate or cure the sequent injury. Merits have been obtained in the last several years on molecular pathways of GMH, but more work is required to further unravel the whole pathophysiology.

Chemerin suppresses neuroinflammation and improves neurological recovery via CaMKK2/AMPK/Nrf2 pathway after germinal matrix hemorrhage in neonatal rats

Chemerin, an adipokine, has been reported to reduce the production of pro-inflammatory cytokines and neutrophil infiltration. This study investigated the role of Chemerin and its natural receptor, ChemR23, as well as its downstream mediator calmodulin-dependent protein kinase kinase 2 (CAMKK2)/adenosine monophosphate-activated protein kinase (AMPK) /Nuclear factor erythroid 2-related factor 2 (Nrf2) following germinal matrix hemorrhage (GMH) in neonatal rats, with a specific focus on inflammation. GMH was induced by intraparenchymal injection of bacterial collagenase (0.3U) in P7 rat pups. The results demonstrated that human recombinant Chemerin (rh-Chemerin) improved neurological and morphological outcomes after GMH. Rh-Chemerin promoted accumulation and proliferation of M2 microglia in periventricular regions at 72 h. Rh-Chemerin increased phosphorylation of CAMKK2, AMPK and expression of Nrf2, and decreased IL-1beta, IL-6 and TNF-alpha levels. Selective inhibition of ChemR23/CAMKK2/AMPK signaling in microglia via intracerebroventricular delivery of liposome-encapsulated specific ChemR23 (Lipo-alpha-NETA), CAMKK2 (Lipo-STO-609) and AMPK (Lipo-Dorsomorphin) inhibitor increased the expression levels of IL-1beta, IL-6 and TNF- alpha, demonstrating that ChemR23/CAMKK2/AMPK signaling in microglia suppressed inflammatory response after GMH. Cumulatively, these data showed that rh-Chemerin ameliorated GMH-induced inflammatory response by promoting ChemR23/CAMKK2/AMPK/Nrf2 pathway, and M2 microglia may be a major mediator of this effect. Thus, rh-Chemerin can serve as a potential agent to reduce the inflammatory response following GMH.

The involvement of neuroinflammation and necroptosis in the hippocampus during vascular dementia

The prevalence of vascular dementia is increasing at an alarming rate. The Confirmation of the clinical diagnosis of vascular dementia depends on post-mortem examination of the brain. In our study, we investigated the vascular disease and neuroinflammation during vascular dementia. Our results showed a β-amyloid deposits, neovascularization, neuronal hypertrophy and neuroinflammation in the hippocampus tissue. Interestingly, the neuroinflammation was characterized by a higher expression of TNF-α, IL-1β, TGF-β and iNOS which are TLR4/RelA pathway dependent. Finally, the finding of necroptosis by impaired blood supply and inflammation state suggests that the cognitive impairment was caused by vascular disease and neuroinflammation.

Intracerebral Hemorrhage in Mice

Intracerebral hemorrhage is the most devastating stroke subtype with high rates of mortality and morbidity. Furthermore, no clinically approved treatment exists that effectively increases survival or improves quality of life for survivors. Effective modeling is necessary to elucidate the pathophysiological mechanisms of intracerebral hemorrhage and evaluate potential therapeutic approaches. Rodent models are most utilized because of their cost-effectiveness, and because rodent brain development and structures are well documented. Herein, we describe two intracerebral hemorrhage mouse models: the autologous blood double-injection and collagenase infusion models.

Bliverdin reductase-A improves neurological function in a germinal matrix hemorrhage rat model

Germinal matrix hemorrhage is induced by stereotaxic injection of collagenase into the germinal matrix of P7 Sprague-Dawley rats. Hemoglobin assay, western blot, immunofluorescence and neurobehavioral tests were used to test the effects of BLVRA on hematoma resolution and anti-inflammatory response. We showed that BLVRA triggered a signaling cascade that ameliorated post-hemorrhagic neurological deficits in both short-term and long-term neurobehavioral tests in a GMH rat model. Specifically, BLVRA inhibited toll-like receptor 4 (TLR4) expression by translocating to the nucleus in an endothelial nitric oxide (eNOS)/nitric oxide (NO)-dependent manner. BLVRA also induced the upregulation of CD36 scavenger receptor level in microglia/microphages, of which the prominent role is to enhance hematoma resolution. However, the beneficial effects of BLVRA were abolished with the knockdown of eNOS, indicating that the eNOS/NO system is an important downstream factor of BLVRA. Our results demonstrate a mechanism of BLVRA modulating hematoma resolution and suppressing inflammation through eNOS/NO/TLR4 pathway in the GMH rat model.

Long-term T cell responses in the brain after an ischemic stroke

Stroke, which occurs during a loss of blood flow to the brain, is a global disease that accounts for 10% of yearly mortality. But stroke is also a leading cause of long-term adult disability, with recovery continuing for months to years after initial stroke onset. This long-term functional recovery from stroke encompasses changes in neuronal structure and function, and occurs throughout the post-stroke brain. Much less understood is whether the adaptive immune cells that infiltrated the brain during acute post-stroke neuroinflammation remain long-term, and if their presence supports or hinders functional recovery. Studies show that T cell subsets and their derived cytokines exhibit diverse protective and detrimental effects in the immediate acute phase following stroke. Interestingly, T cells are also important in regulating physiological behavior, which hints at a potential role in functional recovery after stroke. Moreover, T cell egress into the post-stroke brain might actually peak weeks after stroke onset, suggesting a long-term role for the adaptive immune system in the injured CNS. However, the significance of T cells in the long-term functional and behavioral recovery and repair phase of stroke remains largely unexplored. We summarize here recent work in delineating the beneficial and detrimental effects of T cells after a stroke, including antigen-specific and non-specific effects of T cells in the post-stroke recovery phase. We also highlight the role of T cells in other CNS diseases that may suggest mechanisms for future study of these adaptive immune cells in the ischemic brain.

Mature B cells accelerate wound healing after acute and chronic diabetic skin lesions

Chronic wounds affect 12-15% of patients with diabetes and are associated with a drastic decrease in their quality of life. Here, we demonstrate that purified mature naive B220⁺ /CD19⁺ /IgM⁺ /IgD⁺ B cells improve healing of acute and diabetic murine wounds after a single topical application. B cell treatment significantly accelerated acute wound closure by 2-3 days in wild-type mice and 5-6 days in obese diabetic mice. The treatment led to full closure in 43% of chronic diabetic wounds, as compared to only 5% in saline-treated controls. Applying equivalent numbers of T cells or disrupted B cells failed to reproduce these effects, indicating that live B cells mediated pro-healing responses. Topically applied B cell treatment was associated with significantly reduced scar size, increased collagen deposition and maturation, enhanced angiogenesis, and increased nerve growth into and under the healing wound. β-III tubulin+ nerve endings in scars of wounds treated acutely with B cells showed increased relative expression of growth-associated protein 43. The improved healing associated with B cell treatment was supported by significantly increased fibroblast proliferation and decreased apoptosis in the wound bed and edges, altered kinetics of neutrophil infiltration, as well as an increase in TGF-β and a significant reduction in MMP2 expression in wound granulation tissue. Our findings indicate that the timeline and efficacy of wound healing can be experimentally manipulated through the direct application of mature, naive B cells, which effectively modify the balance of mature immune cell populations within the wound microenvironment and accelerate the healing process.

M2 Monocyte Microparticles Are Increased in Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is a severe neurologic condition with no proven treatment. Recent evidence suggests that monocytes, a heterogenous group of cells with M1 and M2 phenotypes, contribute to secondary damage following ICH. Microparticles are vesicles .1-1 µm in size that are released from cells. We hypothesized that M1 and M2 monocyte microparticles (mMP) would be differentially expressed in ICH cases and controls.

METHODS

In a single-center, prospective, observational study, consecutive ICH cases were enrolled within 12 hours of symptom onset. Age (±5 years)-, race-, and sex-matched controls were recruited. M1 and M2 mMP numbers were determined in plasma samples using flow cytometry and protein biomarkers using standardized assays. The Mann-Whitney U test compared M1 and M2 mMP counts between cases and controls. Standardized regression coefficients compared M1 and M2 mMP with C-reactive protein (CRP) and serum amyloid A (SAA).

RESULTS

Nineteen ICH case-control pairs were enrolled. The median number of M1 mMP was not significantly different between ICH cases (8.63 × 10⁷/milliliter (mL)) compared with controls (8.64 × 10⁷/mL), (P = .525). The median number of M2 mMP was significantly higher in ICH cases (1.61 × 10⁶/mL) compared with controls (4.46 × 10⁵/mL) (P = .027). There were no significant associations for M1 or M2 mMP with CRP or SAA.

CONCLUSION

Higher numbers of M2 mMP in ICH cases compared with controls is hypothesis generating. It may represent differences in the chronic inflammatory status in patients susceptible to ICH, such as cellular activation or apoptosis. Further research is needed, including serial plasma samples, to elucidate the pathophysiology of monocytes and mMP following ICH.

A Systematic Review and Meta-Analysis on the Treatment of Cerebral Hemorrhage with NaoXueShu Oral Liquid

NaoXueShu oral liquid invigorates Qi and promotes blood circulation, which is mainly used for treating the acute stage of the meridian of hemorrhagic apoplexy and acute blood stasis syndrome during early convalescence. Its main clinical manifestations include hemiplegia, mouth askew, hemianesthesia, and inarticulateness. It is used mainly in patients with lobar hemorrhage, basal ganglia, and thalamus of the small amount of bleeding without disturbing consciousness of hypertensive cerebral. The purpose of this study was to evaluate the efficacy and adverse effects of NaoXueShu oral liquid on the treatment of cerebral hemorrhage. In this study, literature on randomized controlled trials was collected from seven databases to evaluate the clinical efficiency of the treatment of cerebral hemorrhage alone or combined with Western medicine. The methodologic quality of the included studies was assessed using a standard Cochrane system review and analyzed using RevMan 5.3.0 software. The study included 14 eligible randomized controlled trials. The results showed that the use of NaoXueShu oral liquid alone or combined with other drugs or auxiliary methods can play a significant role in the treatment of cerebral hemorrhage, especially hypertensive intracerebral hemorrhage.

Apolipoprotein A-I and Paraoxonase-1 Are Potential Blood Biomarkers for Ischemic Stroke Diagnosis

BACKGROUND

Blood biomarkers for ischemic and hemorrhagic stroke diagnosis remain elusive. Recent investigations suggested that apolipoprotein (Apo), matrix metalloproteinase (MMP), and paraoxonase-1 may be associated with stroke. We hypothesized that Apo A-I, Apo C-I, Apo C-III, MMP-3, MMP-9, and paraoxonase-1 are differentially expressed in ischemic stroke, hemorrhagic stroke, and controls.

METHODS

In a single-center prospective observational study, consecutive stroke cases were enrolled if blood samples were obtainable within 12 hours of symptom onset. Age- (±5 years), race-, and sex-matched controls were recruited. Multiplex assays were used to measure protein levels. The Wilcoxon signed-rank test and the Mann-Whitney U-test were used to compare biomarker values between ischemic stroke patients and controls, hemorrhagic stroke patients and controls, and ischemic and hemorrhagic stroke patients. The 95% confidence intervals (CIs) for the difference of 2 medians were calculated.

RESULTS

Fourteen ischemic stroke case-control pairs and 23 intracerebral hemorrhage (ICH) case-control pairs were enrolled. Median Apo A-I levels were lower in ischemic stroke cases versus controls (140 mg/dL versus 175 mg/dL, difference of 35 mg/dL, 95% CI -54 to -16) and in ischemic stroke versus ICH cases (140 mg/dL versus 180 mg/dL, difference of 40 mg/dL, 95% CI -57 to -23). Median paraoxonase-1 was lower in ischemic stroke cases than in both ICH cases and matched controls. Median Apo C-I was slightly lower in ischemic stroke cases than in ICH cases. There were no differences between groups for MMP-3, MMP-9, and Apo C-III.

CONCLUSION

Apo A-I and paraoxonase-1 levels may be clinically useful for ischemic stroke diagnosis and for differentiating between ischemic and hemorrhagic strokes.

PPARγ-induced upregulation of CD36 enhances hematoma resolution and attenuates long-term neurological deficits after germinal matrix hemorrhage in neonatal rats

Germinal matrix hemorrhage remains the leading cause of morbidity and mortality in preterm infants in the United States with little progress made in its clinical management. Survivors are often afflicted with long-term neurological sequelae, including cerebral palsy, mental retardation, hydrocephalus, and psychiatric disorders. Blood clots disrupting normal cerebrospinal fluid circulation and absorption after germinal matrix hemorrhage are thought to be important contributors towards post-hemorrhagic hydrocephalus development. We evaluated if upregulating CD36 scavenger receptor expression in microglia and macrophages through PPARγ stimulation, which was effective in experimental adult cerebral hemorrhage models and is being evaluated clinically, will enhance hematoma resolution and ameliorate long-term brain sequelae using a neonatal rat germinal matrix hemorrhage model. PPARγ stimulation (15d-PGJ2) increased short-term PPARγ and CD36 expression levels as well as enhanced hematoma resolution, which was reversed by a PPARγ antagonist (GW9662) and CD36 siRNA. PPARγ stimulation (15d-PGJ2) also reduced long-term white matter loss and post-hemorrhagic ventricular dilation as well as improved neurofunctional outcomes, which were reversed by a PPARγ antagonist (GW9662). PPARγ-induced upregulation of CD36 in macrophages and microglia is, therefore, critical for enhancing hematoma resolution and ameliorating long-term brain sequelae.

Adaptive Immunity in Neurodegenerative and Neuropsychological Disorders

Neurodegenerative and neuropsychological disorders are becoming a greater proportion of the global disease burden; however the pathogenic mechanisms by which these disorders originate and contribute to disease progression are not well-described. Increasing evidence supports neuroinflammation as a common underlying component associated with the neuropathological processes that effect disease progression. This collection of articles explores the role of adaptive immunity in autoimmunity, neurodegeneration, neurotrauma, and psychological disorders. The section emphasizes the interactions of T cells with innate cellular responses within the CNS and the effects on neurological functions. One recurrent theme is that modified and aggregated self-proteins upregulate innate-mediated inflammation and provide a permissive environment for polarization of T cells to proinflammatory effector cells. Moreover, infiltration and reactivation of those T effector cells exacerbate neuroinflammation and oxidative stress to greater neurotoxic levels. Another recurrent theme in these disorders promotes diminished regulatory functions that reduce control over activated T effector cells and microglia, and ultimately augment proinflammatory conditions. Augmentation of regulatory control is discussed as therapeutic strategies to attenuate neuroinflammation, mitigate neurodegeneration or neuronal dysfunction, and lessen disease progression.

Dynamics of T cell responses after stroke

T cells are integral to the pathophysiology of stroke. The initial inflammatory cascade leads to T cell migration, which results in deleterious and protective effects mediated through CD4(+), CD(8)+, γδ T cells and regulatory T cells, respectively. Cytokines are central to the T cell responses, with key roles established for TNF-α, IFN-γ, IL-17, IL-21 and IL-10. Through communication with the systemic immune system via neural and hormonal pathways, there is also transient immunosuppression after severe strokes. With time, the inflammatory process eventually transforms to one more conducive of repair and recovery, though some evidence also suggests ongoing chronic inflammation. The role of antigen-specific T cell responses requires further investigation. As our understanding develops, there is increasing scope to modulate the T cell response after stroke.