The pivotal role of microglia in injury and the prognosis of subarachnoid hemorrhage

Subarachnoid hemorrhage leads to a series of pathological changes,including vascular spasm,cellular apoptosis,blood–brain barrier damage,cerebral edema,and white matter injury.Microglia,which are the key immune cells in the central nervous system,maintain homeostasis in the neural environment,support neurons,mediate apoptosis,participate in immune regulation,and have neuroprotective effects.Increasing evidence has shown that microglia play a pivotal role in the pathogenesis of subarachnoid hemorrhage and affect the process of injury and the prognosis of subarachnoid hemorrhage.Moreover,microglia play certain neuroprotective roles in the recovery phase of subarachnoid hemorrhage.Several approaches aimed at modulating microglia function are believed to attenuate subarachnoid hemorrhage injury.This provides new targets and ideas for the treatment of subarachnoid hemorrhage.However,an in-depth and comprehensive summary of the role of microglia after subarachnoid hemorrhage is still lacking.This review describes the activation of microglia after subarachnoid hemorrhage and their roles in the pathological processes of vasospasm,neuroinflammation,neuronal apoptosis,blood–brain barrier disruption,cerebral edema,and cerebral white matter lesions.It also discusses the neuroprotective roles of microglia during recovery from subarachnoid hemorrhage and therapeutic advances aimed at modulating microglial function after subarachnoid hemorrhage.Currently,microglia in subarachnoid hemorrhage are targeted with TLR inhibitors,nuclear factor-κB and STAT3 pathway inhibitors,glycine/tyrosine kinases,NLRP3 signaling pathway inhibitors,Gasdermin D inhibitors,vincristine receptorαreceptor agonists,ferroptosis inhibitors,genetic modification techniques,stem cell therapies,and traditional Chinese medicine.However,most of these are still being evaluated at the laboratory stage.More clinical studies and data on subarachnoid hemorrhage are required to improve the treatment of subarachnoid hemorrhage.

Tumor necrosis factor-stimulated gene-6 ameliorates early brain injury after subarachnoid hemorrhage by suppressing NLRC4 inflammasome-mediated astrocyte pyroptosis

Subarachnoid hemorrhage is associated with high morbidity and mortality and lacks effective treatment.Pyroptosis is a crucial mechanism underlying early brain injury after subarachnoid hemorrhage.Previous studies have confirmed that tumor necrosis factor-stimulated gene-6(TSG-6)can exert a neuroprotective effect by suppressing oxidative stress and apoptosis.However,no study to date has explored whether TSG-6 can alleviate pyroptosis in early brain injury after subarachnoid hemorrhage.In this study,a C57BL/6J mouse model of subarachnoid hemorrhage was established using the endovascular perforation method.Our results indicated that TSG-6 expression was predominantly detected in astrocytes,along with NLRC4 and gasdermin-D(GSDMD).The expression of NLRC4,GSDMD and its N-terminal domain(GSDMD-N),and cleaved caspase-1 was significantly enhanced after subarachnoid hemorrhage and accompanied by brain edema and neurological impairment.To explore how TSG-6 affects pyroptosis during early brain injury after subarachnoid hemorrhage,recombinant human TSG-6 or a siRNA targeting TSG-6 was injected into the cerebral ventricles.Exogenous TSG-6 administration downregulated the expression of NLRC4 and pyroptosis-associated proteins and alleviated brain edema and neurological deficits.Moreover,TSG-6 knockdown further increased the expression of NLRC4,which was accompanied by more severe astrocyte pyroptosis.In summary,our study revealed that TSG-6 provides neuroprotection against early brain injury after subarachnoid hemorrhage by suppressing NLRC4 inflammasome activation-induced astrocyte pyroptosis.

Therapeutic potential of stem cells in subarachnoid hemorrhage

Aneurysm rupture can result in subarachnoid hemorrhage,a condition with potentially severe consequences,such as disability and death.In the acute stage,early brain injury manifests as intracranial pressure elevation,global cerebral ischemia,acute hydrocephalus,and direct blood–brain contact due to aneurysm rupture.This may subsequently cause delayed cerebral infarction,often with cerebral vasospasm,significantly affecting patient outcomes.Chronic complications such as brain volume loss and chronic hydrocephalus can further impact outcomes.Investigating the mechanisms of subarachnoid hemorrhage-induced brain injury is paramount for identifying effective treatments.Stem cell therapy,with its multipotent differentiation capacity and anti-inflammatory effects,has emerged as a promising approach for treating previously deemed incurable conditions.This review focuses on the potential application of stem cells in subarachnoid hemorrhage pathology and explores their role in neurogenesis and as a therapeutic intervention in preclinical and clinical subarachnoid hemorrhage studies.

Stem cell exosomes:New hope for recovery from diabetic brain hemorrhage

Recent advancements in stem cell-derived exosome therapy for diabetic brain hemorrhage are discussed in this editorial,which highlights this therapy’s potential for revolutionizing diabetic brain hemorrhage treatment.The paper offers compelling evidence that exosomes can effectively reduce neuroinflammation and promote recovery from diabetic brain hemorrhage.Although these findings are promising,further research is warranted to fully understand the underlying mechanisms and to validate the therapeutic potential of exosomes in clinical settings.The findings of this study indicate that continued exploration should be conducted into exosome-based therapies as a novel approach to managing diabetic brain hemorrhage.

Computed tomographic angiography for diagnosis of post-pancreatoduodenectomy hemorrhage

To the Editor:Even in high volume specialist hepato-pancreato-biliary surgery centres,hemorrhage after pancreatoduodenectomy remains a feared and potentially lethal complication[1]and an important cause of postoperative morbidity and mortality[2].Whilst early hemorrhage after pancreatoduodenectomy is typically managed by re-operation,detection and treatment of bleeding later in the postoperative course can be problematic.Patients who are hemodynamically unstable with evidence of brisk bleeding are usually treated by urgent re-operation.However,not all bleeding episodes present in such a dramatic fashion.The“sentinel bleed”–a harbinger of major hemorrhage–represents a clinical opportunity for detection and treatment[3].Traditionally,patients who presented with luminal bleeding episodes with hematemesis or melena underwent fibre optic endoscopy as first-line investigation whereas patients presenting with a bleed into surgical drains would have undergone selective mesenteric angiography[4].

The value of three-dimensional computed tomographic angiography in the early diagnosis and treatment of spontaneous subarachnoid hemorrhage (616 cases report)

Objective To evaluate the clinical value of three dimensional computerized tomography angiography in the diagnosis and treatment of spontaneous subarachnoid hemorrhage. Methods 616 cases were diagnosed as suspected intracranial aneurysms in 3D CTA system. Computed tomographic scans and CTA studies were

Mitophagy in intracerebral hemorrhage:a new target for therapeutic intervention

Intracerebral hemorrhage is a life-threatening condition with a high fatality rate and severe sequelae.However,there is currently no treatment available for intracerebral hemorrhage,unlike for other stroke subtypes.Recent studies have indicated that mitochondrial dysfunction and mitophagy likely relate to the pathophysiology of intracerebral hemorrhage.Mitophagy,or selective autophagy of mitochondria,is an essential pathway to preserve mitochondrial homeostasis by clearing up damaged mitochondria.Mitophagy markedly contributes to the reduction of secondary brain injury caused by mitochondrial dysfunction after intracerebral hemorrhage.This review provides an overview of the mitochondrial dysfunction that occurs after intracerebral hemorrhage and the underlying mechanisms regarding how mitophagy regulates it,and discusses the new direction of therapeutic strategies targeting mitophagy for intracerebral hemorrhage,aiming to determine the close connection between mitophagy and intracerebral hemorrhage and identify new therapies to modulate mitophagy after intracerebral hemorrhage.In conclusion,although only a small number of drugs modulating mitophagy in intracerebral hemorrhage have been found thus far,most of which are in the preclinical stage and require further investigation,mitophagy is still a very valid and promising therapeutic target for intracerebral hemorrhage in the long run.

Potential therapeutic molecular targets for blood-brain barrier disruption after subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage remains serious hemorrhagic stroke with high morbidities and mortalities.Aneurysm rupture causes arterial bleeding-induced mechanical brain tissue injuries and elevated intracranial pressure,followed by global cerebral ischemia.Post-subarachnoid hemorrhage ischemia,tissue injuries as well as extravasated blood components and the breakdown products activate microglia,astrocytes and Toll-like receptor 4,and disrupt blood-brain barrier associated with the induction of many inflammatory and other cascades.Once blood-brain barrier is disrupted,brain tissues are directly exposed to harmful blood contents and immune cells,which aggravate brain injuries furthermore.Blood-brain barrier disruption after subarachnoid hemorrhage may be developed by a variety of mechanisms including endothelial cell apoptosis and disruption of tight junction proteins.Many molecules and pathways have been reported to disrupt the blood-brain barrier after subarachnoid hemorrhage,but the exact mechanisms remain unclear.Multiple independent and/or interconnected signaling pathways may be involved in blood-brain barrier disruption after subarachnoid hemorrhage.This review provides recent understandings of the mechanisms and the potential therapeutic targets of blood-brain barrier disruption after subarachnoid hemorrhage.

Matricellular proteins as possible biomarkers for early brain injury after aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage remains devastating,and the most important determinant of poor outcome is early brain injury（EBI）.In clinical settings,as a surrogate marker of EBI,loss of consciousness at ictus,poor initial clinical grades,and some radiographic findings are used,but these markers are somewhat subjective.Thus,it is imperative to find biomarkers of EBI that have beneficial prognostic and therapeutic implications.In our opinion,an ideal biomarker is a molecule that is implicated in the pathogenesis of both EBI and subsequently developing delayed cerebral ischemia（DCI）,being a therapeutic target,and can be measured easily in the peripheral blood in an acute stage.A good candidate of such a biomarker is a matricellular protein,which is a secreted,inducible and multifunctional extracellular matrix protein.There are many kinds of matricellular proteins reported,but only tenascin-C,osteopontin,galectin-3 and periostin are reported relevant to EBI and DCI.Reliable biomarkers of EBI may stratify aneurysmal subarachnoid hemorrhage patients into categories of risk to develop DCI,and allow objective monitoring of the response to treatment for EBI and earlier diagnosis of DCI.This review emphasizes that further investigation of matricellular proteins as an avenue for biomarker discovery is warranted.

Statins Protect the Blood Brain Barrier Acutely after Experimental Intracerebral Hemorrhage

Objectives: The goal of this study was to measure the impact of simvastatin and atorvastatin treatment on blood brain barrier (BBB) integrity after experimental intracerebral hemorrhage (ICH). Methods: Primary ICH was induced in 27 male Wistar rats by stereotactic injection of100mL of autologous blood into the striatum. Rats were divided into three groups (n = 9/group): 1) oral treatment (2 mg/kg) of atorvastatin, 2) oral treatment (2 mg/kg) simvastatin, or 3) phosphate buffered saline daily starting 24-hours post-ICH and continuing daily for the next 3 days. On the fourth day, the animals underwent magnetic resonance imaging (MRI) for measurements of T1sat (a marker for BBB integrity), T2 (edema), and cerebral blood flow (CBF). After MRI, the animals were sacrificed and immunohistology or Western blotting was performed. Results: MRI data for animals receiving simvastatin treatment showed significantly reduced BBB dysfunction and improved CBF in the ICH rim compared to controls (P 0.05) 4 days after ICH. Simvastatin also significantly reduced edema (T2) in the rim at 4 days after ICH (P 0.05). Both statin-treated groups demonstrated increased occludin and endothelial barrier antigen levels within the vessel walls, indicating better preservation of BBB function (P 0.05) and increased number of blood vessels (P 0.05). Conclusions: Simvastatin treatment administered acutely after ICH protects BBB integrity as measured by MRI and correlative immunohistochemistry. There was also evidence of improved CBF and reduced edema by MRI. Conversely, atorvastatin showed a non-significant trend by MRI measurement.

Neuroprotection mediated by the Wnt/Frizzled signaling pathway in early brain injury induced by subarachnoid hemorrhage

The Wnt/Frizzled signaling pathway participates in many inflammation-linked diseases. However, the inflammatory response mediated by the Wnt/Frizzled signaling pathway in experimental subarachnoid hemorrhage has not been thoroughly investigated. Consequently, in this study, we examined the potential role of the Wnt/Frizzled signaling pathway in early brain injury in rat models of subarachnoid hemorrhage.Simultaneously, possible neuroprotective mechanisms were also investigated. Experimental subarachnoid hemorrhage rat models were induced by injecting autologous blood into the prechiasmatic cistern. Experiment 1 was designed to examine expression of the Wnt/Frizzled signaling pathway in early brain injury induced by subarachnoid hemorrhage. In total, 42 adult rats were divided into sham(injection of equivalent volume of saline), 6-, 12-, 24-, 48-, 72-hour, and 1-week subarachnoid hemorrhage groups. Experiment 2 was designed to examine neuroprotective mechanisms of the Wnt/Frizzled signaling pathway in early brain injury induced by subarachnoid hemorrhage. Rats were treated with recombinant human Wnt1(rhwnt1), small interfering Wnt1(siwnt1) RNA, and monoclonal antibody of Frizzled1(anti-Frizzled1) at 48 hours after subarachnoid hemorrhage. Expression levels of Wnt1, Frizzled1, β-catenin, peroxisome proliferator-activated receptor-γ, CD36, and active nuclear factor-κB were examined by western blot assay and immunofluorescence staining. Microglia type conversion and inflammatory cytokine levels in brain tissue were examined by immunofluorescence staining and enzyme-linked immunosorbent assay. Our results show that compared with the sham group, expression levels of Wnt1, Frizzled1, and β-catenin were low and reduced to a minimum at 48 hours, gradually returning to baseline at 1 week after subarachnoid hemorrhage. rhwnt1 treatment markedly increased Wnt1 expression and alleviated subarachnoid hemorrhage-induced early brain injury(within 72 hours), including cortical cell apoptosis, brain edema, and neurobehavioral deficits, accompanied by increasing protein levels of β-catenin, CD36, and peroxisome proliferator-activated receptor-γ and decreasing protein levels of nuclear factor-κB. Of note, rhwnt1 promoted M2-type microglia conversion and inhibited release of inflammatory cytokines(interleukin-1β, interleukin-6, and tumor necrosis factor-α). In contrast, siwnt1 RNA and anti-Frizzled1 treatment both resulted in an opposite effect. In conclusion, the Wnt/Frizzled1 signaling pathway may participate in subarachnoid hemorrhage-induced early brain injury via inhibiting the inflammatory response, including regulating microglia type conversion and decreasing inflammatory cytokine release. The study was approved by the Animal Ethics Committee of Anhui Medical University and First Affiliated Hospital of USTC,Division of Life Sciences and Medicine, University of Science and Technology of China(approval No. LLSC-20180202) in May 2017.

Vascular endothelial growth factor A promotes platelet adhesion to collagen Ⅳ and causes early brain injury after subarachnoid hemorrhage

The role of vascular endothelial growth factor A in platelet adhesion in cerebral microvessels in the early stage of subarachnoid hemorrhage remains unclear.In this study,the endovascular puncture method was used to produce a rat model of subarachnoid hemorrhage.Then,30 minutes later,vascular endothelial growth factor A antagonist anti-vascular endothelial growth factor receptor 2 antibody,10μg,was injected into the right ventricle.Immunohistochemistry and western blot assay were used to assess expression of vascular endothelial growth factor A,occludin and claudin-5.Immunohistochemical double labeling was conducted to examine co-expression of GP Ⅰa-Ⅱ integrin and type Ⅳ collagen.TUNEL was used to detect apoptosis in the hippocampus.Neurological score was used to assess behavioral performance.After subarachnoid hemorrhage,the expression of vascular endothelial growth factor A increased in the hippocampus,while occludin and claudin-5 expression levels decreased.Co-expression of GP Ⅰa-Ⅱ integrin and type Ⅳ collagen and the number of apoptotic cells increased,whereas behavioral performance was markedly impaired.After treatment with anti-vascular endothelial growth factor receptor 2 antibody,occludin and claudin-5 expression recovered,while co-expression of GP Ⅰa-Ⅱ integrin and type Ⅳ collagen and the number of apoptotic cells decreased.Furthermore,behavioral performance improved notably.Our findings suggest that increased vascular endothelial growth factor A levels promote platelet adhesion and contribute to early brain injury after subarachnoid hemorrhage.This study was approved by the Biomedical Ethics Committee,Medical College of Xi’an Jiaotong University,China in December 2015.

Role of Glucose-regulated Protein 78 in Early Brain Injury after Experimental Subarachnoid Hemorrhage in Rats

Early brain injury（EBI） plays a key role in the pathogenesis of subarachnoid hemorrhage（SAH）. This study investigated the role of glucose-regulated protein 78（GRP78） in EBI after SAH. Male Sprague-Dawley rats（n=108） weighing 260±40 g were divided into control, sham-operated, and operated groups. Blood was injected into the prechiasmatic cistern of rats in the operated group. Neurological scores, ultrastructures of neurons, apoptosis, and GRP78 expression in the hippocampus were examined using Garcia scoring system, transmission electron microscopy, terminal deoxynucleotidyl transferase-mediated d UTP nick-end labelling, and Western blotting at 1, 6, 12, 24, 48, and 72 h after SAH, respectively. The results showed that neurological scores were significantly decreased in the operated group as compared with those in control and sham-operated groups at 12, 24, 48, and 72 h. Metachromatin, chromatin pyknosis at the edge, endoplasmic reticulum swelling, and invagination of nuclear membrane were observed at 24 h in the operated group, indicating the early morphological changes of apoptosis. The number of apoptotic cells was significantly increased in the operated group as compared with that in control and sham-operated groups at 6, 12, 24, 48, and 72 h. The GRP78 protein expression levels in the operated group were significantly elevated at all time points and reached the peak at 12 h. GRP78 expression was positively associated with apoptosis cells and negatively with neurological scores. In conclusion, EBI was demonstrated to occur after SAH and GRP78 was involved in the development of EBI after SAH.

Toll-like receptor 4 as a possible therapeutic target for delayed brain injuries after aneurysmal subarachnoid hemorrhage

Neuroinflammation is a well-recognized consequence of subarachnoid hemorrhage（SAH）, and Toll-like receptor（TLR） 4 may be an important therapeutic target for post-SAH neuroinflammation. Of the TLR family members, TLR4 is expressed in various cell types in the central nervous system, and is unique in that it can signal through both the myeloid differentiation primary-response protein 88-dependent and the toll receptor associated activator of interferon-dependent cascades to coordinate the maximal inflammatory response. TLR4 can be activated by many endogenous ligands having damage-associated molecular patterns including heme and fibrinogen at the rupture of an intracranial aneurysm, and the resultant inflammatory reaction and thereby tissue damages may furthermore activate TLR4. It is widely accepted that the excreted products of TLR4 signaling alter neuronal functions. Previous studies have focused on the pathway through nuclear factor（NF）-κΒ signaling among TLR4 signaling pathways as to the development of early brain injury（EBI） such as neuronal apoptosis and blood-brain barrier disruption, and cerebral vasospasm. However, many findings suggest that both pathways via NF-κΒ and mitogen-activated protein kinases may be involved in EBI and cerebral vasospasm development. To overcome EBI and cerebral vasospasm is important to improve outcomes after SAH, because both EBI and vasopasm are responsible for delayed brain injuries or delayed cerebral ischemia, the most important preventable cause of poor outcomes after SAH. Increasing evidence has shown that TLR4 signaling plays an important role in SAH-induced brain injuries. Better understanding of the roles of TLR4 signaling in SAH will facilitate development of new treatments.

SOCS1/JAK2/STAT3 axis regulates early brain injury induced by subarachnoid hemorrhage via inflammatory responses

The SOCS1/JAK2/STAT3 axis is strongly associated with tumor growth and progression,and participates in cytokine secretion in many diseases.However,the effects of the SOCS1/JAK2/STAT3 axis in experimental subarachnoid hemorrhage remain to be studied.A subarachnoid hemorrhage model was established in rats by infusing autologous blood into the optic chiasm pool.Some rats were first treated with JAK2/STAT3 small interfering RNA(Si-JAK2/Si-STAT3)or overexpression plasmids of JAK2/STAT3.In the brains of subarachnoid hemorrhage model rats,the expression levels of both JAK2 and STAT3 were upregulated and the expression of SOCS1 was downregulated,reaching a peak at 48 hours after injury.Simultaneously,the interactions between JAK2 and SOCS1 were reduced.In contrast,the interactions between JAK2 and STAT3 were markedly enhanced.Si-JAK2 and Si-STAT3 treatment alleviated cortical neuronal cell apoptosis and necrosis,destruction of the blood-brain barrier,brain edema,and cognitive functional impairment after subarachnoid hemorrhage.This was accompanied by decreased phosphorylation of JAK2 and STAT3 protein,decreased total levels of JAK2 and STAT3 protein,and increased SOCS1 protein expression.However,overexpression of JAK2 and STAT3 exerted opposite effects,aggravating subarachnoid hemorrhage-induced early brain injury.Si-JAK2 and Si-STAT3 inhibited M1-type microglial conversion and the release of pro-inflammatory factors(inducible nitric oxide synthase,interleukin-1β,and tumor necrosis factor-α)and increased the release of anti-inflammatory factors(arginase-1,interleukin-10,and interleukin-4).Furthermore,primary neurons stimulated with oxyhemoglobin were used to simulate subarachnoid hemorrhage in vitro,and the JAK2 inhibitor AG490 was used as an intervention.The in vitro results also suggested that neuronal protection is mediated by the inhibition of JAK2 and STAT3 expression.Together,our findings indicate that the SOCS1/JAK2/STAT3 axis contributes to early brain injury after subarachnoid hemorrhage both in vitro and in vivo by inducing inflammatory responses.This study was approved by the Animal Ethics Committee of Anhui Medical University and the First Affiliated Hospital of University of Science and Technology of China(approval No.LLSC-20180202)on March 1,2018.

Target inhibition of caspase-8 alleviates brain damage after subarachnoid hemorrhage

Caspase-8 plays an important role in the mediation of inflammation and the effect of its role in subarachnoid hemorrhage remains elusive.The nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome has been postulated to mediate inflammation during SAH.The aim of the present study was to investigate the effects of caspase-8 inhibition on SAH injury and further elucidate the molecular mechanisms.In this study,a subarachnoid hemorrhage model was established by endovascular perforation process in adult male Sprague-Dawley rats.Z-IETD-FMK(0.5,1,2 mg/kg;an inhibitor of caspase-8)was delivered via intravenous(tail vein)injection immediately after subarachnoid hemorrhage.After 12 hours of subarachnoid hemorrhage,western blot assay showed that the expression of cleaved caspase-8 was significantly increased at 12 hours,peaked at 24 hours,and then decreased at 72 hours after subarachnoid hemorrhage.Immunofluorescence staining demonstrated that caspase-8 was expressed in microglia after subarachnoid hemorrhage.Z-IETDFMK significantly improved neurological deficits and reduced brain water content 24 hours after subarachnoid hemorrhage.The Morris water maze and rotarod test confirmed that Z-IETD-FMK significantly improved spatial learning and memory abilities and motor coordination at 21–27 days after subarachnoid hemorrhage.Furthermore,inhibition of caspase-8 activation reduced the expression of pyrin domain-containing 3,caspase-1,and interleukin-1βafter subarachnoid hemorrhage.In conclusion,our findings suggest that caspase-8 inhibition alleviates subarachnoid hemorrhage-induced brain injuries by suppressing inflammation.The study was approved by the Institutional Animal Ethics Committee of the First Affiliated Hospital,School of Medicine,Zhejiang University,China(approval No.2016-193)on February 25,2016.

Disseminated intravascular coagulation scores as predictors for progressive hemorrhage and neurological prognosis following traumatic brain injury

Coagulation abnormalities, such as disseminated intravascular coagulation （DIC）, are associated with progressive hemcrrhagic injury （PHI） following head trauma. However, the exact relationship between coagulopathy and PHI remains unclear. The present study utilized a scoring system defined by the International Society of Thrombosis and Haemostasis to investigate whether a high DIC score is predictive for PHI. This study was a multicenter prospective design involving four hospitals, a 6-month observation, and follow-up. Of 352 traumatic brain injury （TBI） patients, serial CT scan indicated approximately one third of patients developed progressive hemorrhage, which was most frequently observed in the frontal, temporal, and orbitofrontal lobes of patients with brain contusion. PHI-positive patients exhibited poor prognosis, as indicated by prolonged length of hospital/intensive care unit stay and high mortality. More importantly, a DIC score after TBI, as well as patient age and sex, could serve as predictors for PHI. In addition, DIC scores were closely associated with injury severity. Therefore, the DIC scoring system facilitated early PHI diagnosis in TBI patients, and DIC scores might serve as a valuable predictor for TBI patients with PHI.

Effects of dexamthasone with different doses on aquaporin-4 in brain of intracerebral hemorrhage rats

Objective：To determine the relationship between the expression of aquaporin-4（AQP4） after intracerebral hemorrhage and dexamethasone treated. Methods：Collagenase Ⅶ was injected in caudate nucleus in a stereotaxis frame to establish the intracerebral hemorrhage（ICH） animal models. The intracerebral hemorrhage（ICH） rats were randomly divided into four groups： the sham group （group A）, the ICH group（group B）, low dose-treated group（group C）, moderate dose group（group D） and high dose group（group E）. The groups were respectively received an intraperitoneal dexamethasone injection with 1 mg/kg, 15 mg/kg, 30 mg/kg, twice a day for three days. The brain water content（BWC）, the permeability of blood-brain barrier（BBB） and the expression of AQP4 were observed. Results：Both the BBB disruption and AQP4 expression decreased in treated groups, and the AQP4 expression had a dose-dependent manner in the dexamethasone treatment. And it seemed that low dose dexamethasone was in favor of brain swelling elimination, but the higher dosage had not similar effect. Conclusion：Dexamethesone may play a critical role on expression of AQP4 in the physiopathology of hemorrhagic edema.

Obstructive sleep apnea aggravates neuroinflammation and pyroptosis in early brain injury following subarachnoid hemorrhage via ASC/HIF-1α pathway

Obstructive sleep apnea can worsen the prognosis of subarachnoid hemorrhage.Howeve r,the underlying mechanism remains unclear.In this study,we established a mouse model of subarachnoid hemorrhage using the endovascular perforation method and exposed the mice to intermittent hypoxia for 8 hours daily for 2 consecutive days to simulate sleep apnea.We found that sleep apnea aggravated brain edema,increased hippocampal neuron apoptosis,and worsened neurological function in this mouse model of subarachnoid hemorrhage.Then,we established an in vitro HT-22 cell model of hemin-induced subarachnoid hemorrhage/intermittent hypoxia and found that the cells died,and lactate dehydrogenase release increased,after 48 hours.We further investigated the underlying mechanism and found that sleep apnea increased the expression of hippocampal neuroinflammatory factors interleukin-1β,interleukin-18,inte rleukin-6,nuclear factorκB,pyro ptosis-related protein caspase-1,pro-caspase-1,and NLRP3,promoted the prolife ration of astrocytes,and increased the expression of hypoxia-inducible factor 1αand apoptosis-associated speck-like protein containing a CARD,which are the key proteins in the hypoxia-inducible factor 1α/apoptosis-associated speck-like protein containing a CARD signaling pathway.We also found that knockdown of hypoxia-inducible factor 1αexpression in vitro greatly reduced the damage to HY22 cells.These findings suggest that sleep apnea aggravates early brain injury after subarachnoid hemorrhage by aggravating neuroinflammation and pyroptosis,at least in part through the hypoxia-inducible factor 1α/apoptosis-associated speck-like protein containing a CARD signaling pathway.

Velamentous Cord Insertion: Interest of Antenatal Diagnosis and Review of the Literature

Velamentous insertion of the umbilical cord corresponds to the insertion of the cord directly on amniotic membranes. It is a rare situation whose frequency varies from 0.5% to 1.69% of single pregnancies. It must be diagnosed during the morphological ultrasound of the 2nd trimester, actively looking for the association with a vasa previa, due to the risk of fetal haemorrhagic threat. We report an antenatal diagnosis of velamentous cord insertion and its management with literature review.