ADAMTS13 controls vascular remodeling by modifying VWF reactivity during stroke recovery

Critical role of Slc22a8 in maintaining blood-brain barrier integrity after experimental cerebral ischemia-reperfusion

Blood-brain barrier (BBB) damage significantly affects the prognosis of ischemic stroke patients. This project employed multi-omics analysis to identify key factors regulating BBB disruption during cerebral ischemia-reperfusion. An integrated analysis of three transcriptome sequencing datasets from mouse middle cerebral artery occlusion/reperfusion (MCAO/R) models identified eight downregulated genes in endothelial cells. Additionally, transcriptome analysis of BBB (cortex) and non-BBB (lung) endothelium of E13.5 mice revealed 2,102 upregulated genes potentially associated with BBB integrity. The eight downregulated genes were intersected with the 2,102 BBB-related genes and mapped using single-cell RNA sequencing data, revealing that solute carrier family 22 member 8 (Slc22a8) is specifically expressed in endothelial cells and pericytes and significantly decreases after MCAO/R. This finding was validated in the mouse MCAO/R model at both protein and mRNA levels in this study. External overexpression of Slc22a8 using a lentivirus carrying Tie2 improved Slc22a8 and tight junction protein levels and reduced BBB leakage after MCAO/R, accompanied by Wnt/β-catenin signaling activation. In conclusion, this study suggested that MCAO/R-induced downregulation of Slc22a8 expression may be a crucial mechanism underlying BBB disruption. Interventions that promote Slc22a8 expression or enhance its function hold promise for improving the prognosis of patients with cerebral ischemia.

Ginsenoside CK cooperates with bone mesenchymal stem cells to enhance angiogenesis post-stroke via GLUT1 and HIF-1α/VEGF pathway

The transplantation of bone marrow mesenchymal stem cells (MSCs) in stroke is hindered by the restricted rates of survival and differentiation. Ginsenoside compound K (CK), is reported to have a neuroprotective effect and regulate energy metabolism. We applied CK to investigate if CK could promote the survival of MSCs and differentiation into brain microvascular endothelial-like cells (BMECs), thereby alleviating stroke symptoms. Therefore, transwell and middle cerebral artery occlusion (MCAO) models were used to mimic oxygen and glucose deprivation (OGD) in vitro and in vivo, respectively. Our results demonstrated that CK had a good affinity for GLUT1, which increased the expression of GLUT1 and the production of ATP, facilitated the proliferation and migration of MSCs, and activated the HIF-1α/VEGF signaling pathway to promote MSC differentiation. Moreover, CK cooperated with MSCs to protect BMECs, promote angiogenesis and vascular density, enhance neuronal and astrocytic proliferation, thereby reducing infarct volume and consequently improving neurobehavioral outcomes. These results suggest that the synergistic effects of CK and MSCs could potentially be a promising strategy for stroke.

Hemostasis and endothelial functionality: the double face of coagulation factors

Hemostasis is a sophisticated sequence of events aimed at repairing vessel injury. This process occurs in combination with angiogenesis, which leads to new blood vessel formation, helping in wound repair and facilitating tissue healing. The fine mechanisms that regulate hemostasis and angiogenesis are well described, but for a long time, coagulation factors (CF) have been considered merely players in the coagulation cascade. However, evidence from several experiments highlights the crucial functions of these CF in regulating endothelial functionality, especially in the angiogenic process. Some of these CF (e.g., thrombin and tissue factor) have been widely investigated and have been described as triggering intracellular signaling related to endothelial cell (EC) functionality. For others (e.g., factor VIII and thrombomodulin), potential receptors and molecular mechanisms have not been fully elucidated but some data show their potential to induce EC response. This review focuses on the emerging roles of selected CF in regulating EC functions, highlighting in particular their ability to activate signaling pathways involved in angiogenesis, migration, proliferation and endothelial barrier stability.

The effect of ADAMTS13 on graft-versus-host disease

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) can potentially cure malignant blood disorders and benign conditions such as haemoglobinopathies and immunologic diseases. However, allo-HSCT is associated with significant complications. The most common and debilitating among them is graft-versus-host disease (GVHD). In GVHD, donor-derived T cells mount an alloimmune response against the recipient. The alloimmune response involves several steps, including recognition of recipient antigens, activation and proliferation of T cells in secondary lymphoid organs, and homing into GVHD-targeted organs. Adhesion molecules on T cells and endothelial cells mediate homing of T cells into lymphoid and non-lymphoid tissues. In this study, we showed that Von Willebrand factor (VWF), an adhesion molecule secreted by activated endothelial cells, plays an important role in mouse models of GVHD. We investigated the effect of the VWF-cleaving protease ADAMTS13 on GVHD. We found that ADAMTS13 reduced the severity of GVHD after bone marrow transplantation from C57BL6 donor to BALB/C recipient mice. A recombinant VWF-A2 domain peptide also reduced GVHD in mice. We showed that ADAMTS13 and recombinant VWF-A2 reduced the binding of T cells to endothelial cells and VWF in vitro, and reduced the number of T cells in lymph nodes, Peyer's patches and GVHD-targeted organs in vivo. We identified LFA-1 (αLβ2) as the binding site of VWF on T cells. Our results showed that blocking T-cell homing by ADAMTS13 or VWF-A2 peptide reduced the severity of the GVHD after allo-HSCT, a potentially novel method for treating and preventing GVHD.

Synergistic promotion of angiogenesis after intracerebral hemorrhage by ginsenoside Rh2 and chrysophanol in rats

BACKGROUND

Intracerebral hemorrhage (ICH) is a debilitating condition characterized by the rupture of cerebral blood vessels, resulting in profound neurological deficits. A significant challenge in the treatment of ICH lies in the brain's limited capacity to regenerate damaged blood vessels. This study explores the potential synergistic effects of Ginsenoside Rh2 and Chrysophanol in promoting angiogenesis following ICH in a rat model.

METHODS

Network pharmacology was employed to predict the potential targets and pathways of Ginsenoside Rh2 and Chrysophanol for ICH treatment. Molecular docking was utilized to assess the binding affinity between these compounds and their respective targets. Experimental ICH was induced in male Sprague-Dawley rats through stereotactic injection of type VII collagenase into the right caudate putamen (CPu). The study encompassed various methodologies, including administration protocols, assessments of neurological function, magnetic resonance imaging, histological examination, observation of brain tissue ultrastructure, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), immunofluorescence staining, Western blot analysis, and statistical analyses.

RESULTS

Network pharmacology analysis indicated that Ginsenoside Rh2 and Chrysophanol may exert their therapeutic effects in ICH by promoting angiogenesis. Results from animal experiments revealed that rats treated with Ginsenoside Rh2 and Chrysophanol exhibited significantly improved neurological function, reduced hematoma volume, and diminished pathological injury compared to the Model group. Immunofluorescence analysis demonstrated enhanced expression of vascular endothelial growth factor receptor 2 (VEGFR2) and CD31, signifying augmented angiogenesis in the peri-hematomal region following combination therapy. Importantly, the addition of a VEGFR2 inhibitor reversed the increased expression of VEGFR2 and CD31. Furthermore, Western blot analysis revealed upregulated expression of angiogenesis-related factors, including VEGFR2, SRC, AKT1, MAPK1, and MAPK14, in the combination therapy group, but this effect was abrogated upon VEGFR2 inhibitor administration.

CONCLUSION

The synergistic effect of Ginsenoside Rh2 and Chrysophanol demonstrated a notable protective impact on ICH injury in rats, specifically attributed to their facilitation of angiogenesis. Consequently, this research offers a foundation for the utilization of Ginsenosides Rh2 and Chrysophanol in medical settings and offers direction for the advancement of novel pharmaceuticals for the clinical management of ICH.

A promising frontier: targeting NETs for stroke treatment breakthroughs

Stroke is a prevalent global acute cerebrovascular condition, with ischaemic stroke being the most frequently occurring type. After a stroke, neutrophils accumulate in the brain and subsequently generate and release neutrophil extracellular traps (NETs). The accumulation of NETs exacerbates the impairment of the blood‒brain barrier (BBB), hampers neovascularization, induces notable neurological deficits, worsens the prognosis of stroke patients, and can facilitate the occurrence of t-PA-induced cerebral haemorrhage subsequent to ischaemic stroke. Alternative approaches to pharmacological thrombolysis or endovascular thrombectomy are being explored, and targeting NETs is a promising treatment that warrants further investigation.

Von Willebrand factor promotes radiation-induced intestinal injury (RIII) development and its cleavage enzyme rhADAMTS13 protects against RIII by reducing inflammation and oxidative stress

Patients with abdominopelvic cancer undergoing radiotherapy commonly develop radiation-induced intestinal injury (RIII); however, its underlying pathogenesis remains elusive. The von Willebrand factor (vWF)/a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) axis has been implicated in thrombosis, inflammation, and oxidative stress. However, its role in RIII remains unclear. In this study, the effect of radiation on vWF and ADAMTS13 expression was firstly evaluated in patients with cervical cancer undergoing radiotherapy and C57BL/6J mice exposed to different doses of total abdominal irradiation. Then, mice with the specific deletion of vWF in the platelets and endothelium were established to demonstrate the contribution of vWF to RIII. Additionally, the radioprotective effect of recombinant human (rh) ADAMTS13 against RIII was assessed. Results showed that both the patients with cervical cancer undergoing radiotherapy and RIII mouse model exhibited increased vWF levels and decreased ADAMTS13 levels. The knockout of platelet- and endothelium-derived vWF rectified the vWF/ADAMTS13 axis imbalance; improved intestinal structural damage; increased crypt epithelial cell proliferation; and reduced radiation-induced apoptosis, inflammation, and oxidative stress, thereby alleviating RIII. Administration of rhADAMTS13 could equally alleviate RIII. Our results demonstrated that abdominal irradiation affected the balance of the vWF/ADAMTS13 axis. vWF exerted a deleterious role and ADAMTS13 exhibited a protective role in RIII progression. rhADAMTS13 has the potential to be developed into a radioprotective agent.

Cerebral glucagon-like peptide-1 receptor activation alleviates traumatic brain injury by glymphatic system regulation in mice

AIM

We aimed to assess the effects of cerebral glucagon-like peptide-1 receptor (GLP-1R) activation on the glymphatic system and whether this effect was therapeutic for traumatic brain injury (TBI).

METHODS

Immunofluorescence was employed to evaluate glymphatic system function. The blood-brain barrier (BBB) permeability, microvascular basement membrane, and tight junction expression were assessed using Evans blue extravasation, immunofluorescence, and western blot. Immunohistochemistry was performed to assess axonal damage. Neuronal apoptosis was evaluated using Nissl staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, and western blot. Cognitive function was assessed using behavioral tests.

RESULTS

Cerebral GLP-1R activation restored glymphatic transport following TBI, alleviating BBB disruption and neuronal apoptosis, thereby improving cognitive function following TBI. Glymphatic function suppression by treatment using aquaporin 4 inhibitor TGN-020 abolished the protective effect of the GLP-1R agonist against cognitive impairment.

CONCLUSION

Cerebral GLP-1R activation can effectively ameliorate neuropathological changes and cognitive impairment following TBI; the underlying mechanism could involve the repair of the glymphatic system damaged by TBI.

Enabling Survival of Transplanted Neural Precursor Cells in the Ischemic Brain

There is no effective therapy for ischemic stroke following the acute stage. Neural transplantation offers a potential option for repairing the ischemic lesion. However, this strategy is hindered by the poor survival of the neural precursor cells (NPCs) that are transplanted into the inflammatory ischemic core. Here, a chemical cocktail consisting of fibrinogen and maraviroc is developed to promote the survival of the transplanted NPCs in the ischemic core of the mouse cerebral cortex. The grafted NPCs survive in the presence of the cocktail but not fibrinogen or maraviroc alone at day 7. The surviving NPCs divide and differentiate to mature neurons by day 30, reconstituting the infarct cortex with vascularization. Molecular analysis in vivo and in vitro shows that blocking the activation of CCR5 on the NPCs protects the NPCs from apoptosis induced by pro-inflammatory factors, revealing the underlying protective effect of the cocktail for NPCs. The findings open an avenue to enable survival of the transplanted NPCs under the inflammatory neurological conditions like stroke.

Novel insight into cGAS-STING pathway in ischemic stroke: from pre- to post-disease

Ischemic stroke, a primary cause of disability and the second leading cause of mortality, has emerged as an urgent public health issue. Growing evidence suggests that the Cyclic GMP-AMP synthase (cGAS)- Stimulator of interferon genes (STING) pathway, a component of innate immunity, is closely associated with microglia activation, neuroinflammation, and regulated cell death in ischemic stroke. However, the mechanisms underlying this pathway remain inadequately understood. This article comprehensively reviews the existing literature on the cGAS-STING pathway and its multifaceted relationship with ischemic stroke. Initially, it examines how various risk factors and pre-disease mechanisms such as metabolic dysfunction and senescence (e.g., hypertension, hyperglycemia, hyperlipidemia) affect the cGAS-STING pathway in relation to ischemic stroke. Subsequently, we explore in depth the potential pathophysiological relationship between this pathway and oxidative stress, endoplasmic reticulum stress, neuroinflammation as well as regulated cell death including ferroptosis and PANoptosis following cerebral ischemia injury. Finally, it suggests that intervention targeting the cGAS-STING pathway may serve as promising therapeutic strategies for addressing neuroinflammation associated with ischemic stroke. Taken together, this review concludes that targeting the microglia cGAS-STING pathway may shed light on the exploration of new therapeutic strategies against ischemic stroke.

Butylphthalide improves brain damage induced by renal ischemia-reperfusion injury rats through Nrf2/HO-1 and NOD2/MAPK/NF-κB pathways

Renal ischemia-reperfusion (I/R) injury leads to irreversible brain damage with serious consequences. Activation of oxidative stress and release of inflammatory mediators are considered potential pathological mechanisms. Butylphthalide (NBP) has anti-inflammatory and antioxidant effects on I/R injuries. However, it is unclear whether NBP can effectively mitigate renal I/R secondary to brain injury as well as its mechanism, which are the aims of this study. Both renal I/R injury rats and oxygen and glucose deprivation cell models were established and pre-intervened NBP. The Morris water maze assay was used to detect behavior. Hippocampal histopathology and function were examined after renal I/R. Apoptosis and tube-forming capacity of brain microvascular endothelial cells (BMVECs) were tested. Immunohistochemistry and Western blot were used to measure protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2)/Heme Oxygenase-1 (HO-1) pathway and NOD-like receptor C2 (NOD2)/Mitogen-activated protein kinases (MAPK)/Nuclear factor kappa-B (NF-κB) pathway. NBP treatment attenuated renal I/R-induced brain tissue damage and learning and memory dysfunction. NBP treatment inhibited apoptosis and promoted blood-brain barrier restoration and microangiogenesis. Also, it decreased oxidative stress levels and pro-inflammatory factor expression in renal I/R rats. Furthermore, NBP enhanced BMVECs' viability and tube-forming capacity while inhibiting apoptosis and oxidative stress. Notably, the alleviating effects of NBP were attributed to Nrf2/HO-1 pathway activation and NOD2/MAPK/NF-κB inhibition. This study demonstrates that NBP maintains BBB function by activating the Nrf2/HO-1 pathway and inhibiting the NOD2/MAPK/NF-κB pathway to suppress inflammation and oxidative stress, thereby alleviating renal I/R-induced brain injury.

Pro‑angiogenic activity of salvianolate and its potential therapeutic effect against acute cerebral ischemia

Salvianolate (Sal) is a medicinal composition that is widely used in China for the treatment of coronary heart disease and angina pectoris. The aim of the present study was to investigate the potential macrophage-mediated pro-angiogenic effects of Sal in vitro. In addition, another aim was to explore the effects of Sal in a rat model of transient middle cerebral artery occlusion (tMCAO) along with the potential mechanism by which it promotes angiogenesis. In this study, human umbilical vein endothelial cells (HUVECs) and Raw264.7 macrophages in vitro, and a rat tMCAO model in vivo were used to detect the pro-angiogenic effect and mechanism of Sal. The results of in vitro experiments showed that the viability, migration and tube formation of HUVECs were promoted by the supernatant of Sal-treated Raw264.7 macrophages (s-Sal) but not by Sal alone. s-Sal also increased the levels of phosphorylated (p-)VEGFR-2, p-AKT and p-p38 MAPK in HUVECs while Sal alone did not. In vivo, treatment with Sal significantly reduced the cerebral infarction volume and neurological deficit scores in the rat tMCAO model. Similar to the mechanism observed in the in vitro experiments, Sal treatment upregulated the protein expression of VEGF and VEGFR-2, in addition to the phosphorylation of VEGFR-2, AKT and p38, in the brain tissues of the tMCAO model rats. In summary, the results of the present study suggest that the mechanism of Sal-mediated angiogenesis is associated with stimulation of the VEGF/VEGFR-2 signaling pathway by macrophages. This suggests the potential of Sal as a therapeutic option for the treatment of acute cerebral ischemic injury, which may act via the promotion of angiogenesis.

von Willebrand factor binds to angiopoietin-2 within endothelial cells and after release from Weibel-Palade bodies

BACKGROUND

The von Willebrand factor (VWF) is a multimeric plasma glycoprotein essential for hemostasis, inflammation, and angiogenesis. The majority of VWF is synthesized by endothelial cells (ECs) and stored in Weibel-Palade bodies (WPB). Among the range of proteins shown to co-localize to WPB is angiopoietin-2 (Angpt-2), a ligand of the receptor tyrosine kinase Tie-2. We have previously shown that VWF itself regulates angiogenesis, raising the hypothesis that some of the angiogenic activity of VWF may be mediated by its interaction with Angpt-2.

METHODS

Static-binding assays were used to probe the interaction between Angpt-2 and VWF. Binding in media from cultured human umbilical vein ECs s and in plasma was determined by immunoprecipitation experiments. Immunofluorescence was used to detect the presence of Angpt-2 on VWF strings, and flow assays were used to investigate the effect on VWF function.

RESULTS

Static-binding assays revealed that Angpt-2 bound to VWF with high affinity (KD,app ∼3 nM) in a pH and calcium-dependent manner. The interaction was localized to the VWF A1 domain. Co-immunoprecipitation experiments demonstrated that the complex persisted following stimulated secretion from ECs and was present in plasma. Angpt-2 was also visible on VWF strings on stimulated ECs. The VWF-Angpt-2 complex did not inhibit the binding of Angpt-2 to Tie-2 and did not significantly interfere with VWF-platelet capture.

CONCLUSIONS

Together, these data demonstrate a direct binding interaction between Angpt-2 and VWF that persists after secretion. VWF may act to localize Angpt-2; further work is required to establish the functional consequences of this interaction.

Gastrointestinal bleeding in von Willebrand patients: special diagnostic and management considerations

INTRODUCTION

Severe and recurrent gastrointestinal (GI) bleeding caused by angiodysplasia is a significant problem in patients with von Willebrand disease (VWD) and in those with acquired von Willebrand syndrome (AVWS). At present, angiodysplasia-related GI bleeding is often refractory to standard treatment including replacement therapy with von Willebrand factor (VWF) concentrates and continues to remain a major challenge and cause of significant morbidity in patients despite advances in diagnostics and therapeutics.

AREAS COVERED

This paper reviews the available literature on GI bleeding in VWD patients, examines the molecular mechanisms implicated in angiodysplasia-related GI bleeding, and summarizes existing strategies in the management of bleeding GI angiodysplasia in patients with VWF abnormalities. Suggestions are made for further research directions.

EXPERT OPINION

Bleeding from angiodysplasia poses a significant challenge for individuals with abnormal VWF. Diagnosis remains a challenge and may require multiple radiologic and endoscopic investigations. Additionally, there is a need for enhanced understanding at a molecular level to identify effective therapies. Future studies of VWF replacement therapies using newer formulations as well as other adjunctive treatments to prevent and treat bleeding will hopefully improve care.

Biomarkers and the outcomes of ischemic stroke

Biomarkers are measurable substances that could be used as objective indicators for disease diagnosis, responses to treatments, and outcomes predictions. In this review, we summarized the data on a number of important biomarkers including glutamate, S100B, glial fibrillary acidic protein, receptor for advanced glycation end-products, intercellular adhesion molecule-1, von willebrand factor, matrix metalloproteinase-9, interleukin-6, tumor necrosis factor-a, activated protein C, copeptin, neuron-specific enolase, tau protein, gamma aminobutyric acid, blood glucose, endothelial progenitor cells, and circulating CD34-positive cells that could be potentially used to indicate the disease burden and/or predict clinical outcome of ischemic stroke. We examined the relationship between specific biomarkers and disease burden and outcomes and discussed the potential mechanisms underlying the relationship. The clinical significance and implications of these biomarkers were also discussed.

The effects of coagulation factors on the risk of endometriosis: a Mendelian randomization study

BACKGROUND

Endometriosis is recognized as a complex gynecological disorder that can cause severe pain and infertility, affecting 6-10% of all reproductive-aged women. Endometriosis is a condition in which endometrial tissue, which normally lines the inside of the uterus, deposits in other tissues. The etiology and pathogenesis of endometriosis remain ambiguous. Despite debates, it is generally agreed that endometriosis is a chronic inflammatory disease, and patients with endometriosis appear to be in a hypercoagulable state. The coagulation system plays important roles in hemostasis and inflammatory responses. Therefore, the purpose of this study is to use publicly available GWAS summary statistics to examine the causal relationship between coagulation factors and the risk of endometriosis.

METHODS

To investigate the causal relationship between coagulation factors and the risk of endometriosis, a two-sample Mendelian randomization (MR) analytic framework was used. A series of quality control procedures were followed in order to select eligible instrumental variables that were strongly associated with the exposures (vWF, ADAMTS13, aPTT, FVIII, FXI, FVII, FX, ETP, PAI-1, protein C, and plasmin). Two independent cohorts of European ancestry with endometriosis GWAS summary statistics were used: UK Biobank (4354 cases and 217,500 controls) and FinnGen (8288 cases and 68,969 controls). We conducted MR analyses separately in the UK Biobank and FinnGen, followed by a meta-analysis. The Cochran's Q test, MR-Egger intercept test, and leave-one-out sensitivity analyses were used to assess the heterogeneities, horizontal pleiotropy, and stabilities of SNPs in endometriosis.

RESULTS

Our two-sample MR analysis of 11 coagulation factors in the UK Biobank suggested a reliable causal effect of genetically predicted plasma ADAMTS13 level on decreased endometriosis risk. A negative causal effect of ADAMTS13 and a positive causal effect of vWF on endometriosis were observed in the FinnGen. In the meta-analysis, the causal associations remained significant with a strong effect size. The MR analyses also identified potential causal effects of ADAMTS13 and vWF on different sub-phenotypes of endometrioses.

CONCLUSIONS

Our MR analysis based on GWAS data from large-scale population studies demonstrated the causal associations between ADAMTS13/vWF and the risk of endometriosis. These findings suggest that these coagulation factors are involved in the development of endometriosis and may represent potential therapeutic targets for the management of this complex disease.

Clinical Manifestations, Current and Future Therapy, and Long-Term Outcomes in Congenital Thrombotic Thrombocytopenic Purpura

Congenital thrombotic thrombocytopenic purpura (cTTP) is an extremely rare disease characterized by the severe deficiency of a disintegrin and metalloproteinase with thrombospondin type 1 motifs 13 (ADAMTS13), caused by ADAMTS13 mutations. While ADAMTS13 supplementation by fresh frozen plasma (FFP) infusion immediately corrects platelet consumption and resolves thrombotic symptoms in acute episodes, FFP treatment can lead to intolerant allergic reactions and frequent hospital visits. Up to 70% of patients depend on regular FFP infusions to normalize their platelet counts and avoid systemic symptoms, including headache, fatigue, and weakness. The remaining patients do not receive regular FFP infusions, mainly because their platelet counts are maintained within the normal range or because they are symptom-free without FFP infusions. However, the target peak and trough levels of ADAMTS13 to prevent long-term comorbidity with prophylactic FFP and the necessity of treating FFP-independent patients in terms of long-term clinical outcomes are yet to be determined. Our recent study suggests that the current volumes of FFP infusions are insufficient to prevent frequent thrombotic events and long-term ischemic organ damage. This review focuses on the current management of cTTP and its associated issues, followed by the importance of upcoming recombinant ADAMTS13 therapy.

From the Discovery of ADAMTS13 to Current Understanding of Its Role in Health and Disease

ADAMTS13 (a disintegrin-like metalloprotease domain with thrombospondin type 1 motif, member 13) is a protease of crucial importance in the regulation of the size of von Willebrand factor multimers. Very low ADAMTS13 activity levels result in thrombotic thrombocytopenic purpura, a rare and life-threatening disease. The mechanisms involved can either be acquired (immune-mediated thrombotic thrombocytopenic purpura [iTTP]) or congenital (cTTP, Upshaw-Schulman syndrome) caused by the autosomal recessive inheritance of disease-causing variants (DCVs) located along the ADAMTS13 gene, which is located in chromosome 9q34. Apart from its role in TTP, and as a regulator of microthrombosis, ADAMTS13 has begun to be identified as a prognostic and/or diagnostic marker of other diseases, such as those related to inflammatory processes, liver damage, metastasis of malignancies, sepsis, and different disorders related to angiogenesis. Since its first description almost 100 years ago, the improvement of laboratory tests and the description of novel DCVs along the ADAMTS13 gene have contributed to a better and faster diagnosis of patients under critical conditions. The ability of ADAMTS13 to dissolve platelet aggregates in vitro and its antithrombotic properties makes recombinant human ADAMTS13 treatment a potential therapeutic approach targeting not only patients with cTTP but also other medical conditions.

Epigenetics and stroke: role of DNA methylation and effect of aging on blood-brain barrier recovery

Incomplete recovery of blood-brain barrier (BBB) function contributes to stroke outcomes. How the BBB recovers after stroke remains largely unknown. Emerging evidence suggests that epigenetic factors play a significant role in regulating post-stroke BBB recovery. This study aimed to evaluate the epigenetic and transcriptional profile of cerebral microvessels after thromboembolic (TE) stroke to define potential causes of limited BBB recovery. RNA-sequencing and reduced representation bisulfite sequencing (RRBS) analyses were performed using microvessels isolated from young (6 months) and old (18 months) mice seven days poststroke compared to age-matched sham controls. DNA methylation profiling of poststroke brain microvessels revealed 11,287 differentially methylated regions (DMR) in old and 9818 DMR in young mice, corresponding to annotated genes. These DMR were enriched in genes encoding cell structural proteins (e.g., cell junction, and cell polarity, actin cytoskeleton, extracellular matrix), transporters and channels (e.g., potassium transmembrane transporter, organic anion and inorganic cation transporters, calcium ion transport), and proteins involved in endothelial cell processes (e.g., angiogenesis/vasculogenesis, cell signaling and transcription regulation). Integrated analysis of methylation and RNA sequencing identified changes in cell junctions (occludin), actin remodeling (ezrin) as well as signaling pathways like Rho GTPase (RhoA and Cdc42ep4). Aging as a hub of aberrant methylation affected BBB recovery processes by profound alterations (hypermethylation and repression) in structural protein expression (e.g., claudin-5) as well as activation of a set of genes involved in endothelial to mesenchymal transformation (e.g., Sox9, Snai1), repression of angiogenesis and epigenetic regulation. These findings revealed that DNA methylation plays an important role in regulating BBB repair after stroke, through regulating processes associated with BBB restoration and prevalently with processes enhancing BBB injury.

Butyrate promotes post-stroke outcomes in aged mice via interleukin-22

Aging increases the risk of stroke, may exacerbate neuroinflammatory responses, reduce angiogenesis, and promote white matter damage post-stroke, all of which contribute to long-term functional recovery. Butyric acid, an important gut microbial metabolite, showed the highest correlation with the outcomes of ischemic stroke, and butyrate was selected as an effective treatment for aged stroke mice. Here, we tested the neurorestorative effect and potential therapeutic mechanisms of butyrate in aged mice with stroke. Aged male C57BL/6 J mice (17-19 months) were subjected to photothrombotic stroke. We performed butyrate supplementation in the drinking water for 3 weeks before surgery until 14 days after the stroke. At 14 days after ischemic stroke, white matter damage, leukocyte infiltration, and blood-brain barrier permeability were all decreased in the aged stroke mice that received the butyrate treatment, which also improved neurological outcomes by stimulating angiogenesis. Stroke reduces the level of interleukin-22 (IL-22) and butyrate treatment significantly enhanced IL-22 expression in the brain. To further validate the mechanisms of butyrate promoting neurological function after stroke, monoclonal antibodies were used to block IL-22 in aged stroke mice when butyrate treatment was provided. Blocking IL-22 in butyrate-treated aged stroke fails to improve functional outcomes and attenuated butyrate-induced angiogenesis, increased axon/white matter density and blood-brain barrier (BBB) integrity, but has no effect on inflammatory cells infiltration. In conclusion, butyrate improves outcomes in aged mice after stroke by promoting angiogenesis and BBB integrity and reducing leukocyte infiltration. To some extent, IL-22 may contribute to butyrate treatment induced vascular remodeling and increased BBB integrity responses in aged stroke mice.

Epigenetics and stroke: role of DNA methylation and effect of aging on blood-brain barrier recovery

Incomplete recovery of blood-brain barrier (BBB) function contributes to stroke outcomes. How the BBB recovers after stroke remains largely unknown. Emerging evidence suggests that epigenetic factors play a significant role in regulating post-stroke BBB recovery. This study aimed to evaluate the epigenetic and transcriptional profile of cerebral microvessels after thromboembolic (TE) stroke to define potential causes of limited BBB recovery. RNA-sequencing and reduced representation bisulfite sequencing (RRBS) analyses were performed using microvessels isolated from young (6 months) and old (18 months) mice seven days poststroke compared to age-matched sham controls. DNA methylation profiling of poststroke brain microvessels revealed 11287 differentially methylated regions (DMR) in old and 9818 DMR in young mice, corresponding to annotated genes. These DMR were enriched in genes encoding cell structural proteins (e.g., cell junction, and cell polarity, actin cytoskeleton, extracellular matrix), transporters and channels (e.g., potassium transmembrane transporter, organic anion and inorganic cation transporters, calcium ion transport), and proteins involved in endothelial cell processes (e.g., angiogenesis/vasculogenesis, cell signaling and transcription regulation). Integrated analysis of methylation and RNA sequencing identified changes in cell junctions (occludin), actin remodeling (ezrin) as well as signaling pathways like Rho GTPase (RhoA and Cdc42ep4). Aging as a hub of aberrant methylation affected BBB recovery processes by profound alterations (hypermethylation and repression) in structural protein expression (e.g., claudin-5) as well as activation of a set of genes involved in endothelial to mesenchymal transformation (e.g., Sox17 , Snail1 ), repression of angiogenesis and epigenetic regulation. These findings revealed that DNA methylation plays an important role in regulating BBB repair after stroke, through regulating processes associated with BBB restoration and prevalently with processes enhancing BBB injury.

Research advances in cGAS-stimulator of interferon genes pathway and central nervous system diseases: Focus on new therapeutic approaches

Cyclic GMP-AMP synthase (cGAS), a crucial innate immune sensor, recognizes cytosolic DNA and induces stimulator of interferon genes (STING) to produce type I interferon and other proinflammatory cytokines, thereby mediating innate immune signaling. The cGAS-STING pathway is involved in the regulation of infectious diseases, anti-tumor immunity, and autoimmune diseases; in addition, it plays a key role in the development of central nervous system (CNS) diseases. Therapeutics targeting the modulation of cGAS-STING have promising clinical applications. Here, we summarize the cGAS-STING signaling mechanism and the recent research on its role in CNS diseases.

Effect of molecular hydrogen treatment on Sepsis-Associated encephalopathy in mice based on gut microbiota

INTRODUCTION

In our experiments, male wild-type mice were randomly divided into four groups: the sham, SAE, SAE + 2% hydrogen gas inhalation (H₂ ), and SAE + hydrogen-rich water (HW) groups. The feces of the mice were collected for 16 S rDNA analysis 24 h after the models were established, and the serum and brain tissue of the mice were collected for nontargeted metabolomics analysis.

AIM

Destruction of the intestinal microbiota is a risk factor for sepsis and subsequent organ dysfunction, and up to 70% of severely ill patients with sepsis exhibit varying degrees of sepsis-associated encephalopathy (SAE). The pathogenesis of SAE remains unclear. We aimed to explore the changes in gut microbiota in SAE and the regulatory mechanism of molecular hydrogen.

RESULTS

Molecular hydrogen treatment significantly improved the functional outcome of SAE and downregulated inflammatory reactions in both the brain and the gut. In addition, molecular hydrogen treatment improved gut microbiota dysbiosis and partially amended metabolic disorder after SAE.

CONCLUSIONS

Molecular hydrogen treatment promotes functional outcomes after SAE in mice, which may be attributable to increasing beneficial bacteria, repressing harmful bacteria, and metabolic disorder, and reducing inflammation.

Mechanisms of ADAMTS13 regulation

Recombinant ADAMTS13 is currently undergoing clinical trials as a treatment for hereditary thrombotic thrombocytopenic purpura, a lethal microvascular condition resulting from ADAMTS13 deficiency. Preclinical studies have also demonstrated its efficacy in treating arterial thrombosis and inflammation without causing bleeding, suggesting that recombinant ADAMTS13 may have broad applicability as an antithrombotic agent. Despite this progress, we currently do not understand the mechanisms that regulate ADAMTS13 activity in vivo. ADAMTS13 evades canonical means of protease regulation because it is secreted as an active enzyme and has a long half-life in circulation, suggesting that it is not inhibited by natural protease inhibitors. Although shear can spatially and temporally activate von Willebrand factor to capture circulating platelets, it is also required for cleavage by ADAMTS13. Therefore, spatial and temporal regulation of ADAMTS13 activity may be required to stabilize von Willebrand factor-platelet strings at sites of vascular injury. This review outlines potential mechanisms that regulate ADAMTS13 in vivo including shear-dependency, local inactivation, and biochemical and structural regulation of substrate binding. Recently published structural data of ADAMTS13 is discussed, which may help to generate novel hypotheses for future research.

Neuroprotective Effect of Angiopoietin2 Is Associated with Angiogenesis in Mouse Brain Following Ischemic Stroke

Angiogenic factors play an important role in protecting, repairing, and reconstructing vessels after ischemic stroke. In the brains of transient focal cerebral ischemic mice, we observed a reduction in infarct volume after the administration of Angiopoietin 2 (Angpt2), but whether this process is promoted by Angpt2-induced angiogenesis has not been fully elaborated. Therefore, this study explored the angiogenic activities, in reference to CD34 which is a marker of activated ECs and blood vessels, of cultured ECs in vitro and in ischemic damaged cerebral area in mice following Angpt2 administration. Our results demonstrate that Angpt2 administration (100 ng/mL) is neuroprotective by significantly increasing the CD34 expression in in vitro-cultured ECs, reducing the infarct volume and mitigating neuronal loss, as well as enhancing CD34⁺ vascular length and area. In conclusion, these results indicate that Angpt2 promotes repair and attenuates ischemic injury, and that the mechanism of this is closely associated with angiogenesis in the brain after stroke.

Endothelial Cells and the Cerebral Circulation

Endothelial cells form the innermost layer of all blood vessels and are the only vascular component that remains throughout all vascular segments. The cerebral vasculature has several unique properties not found in the peripheral circulation; this requires that the cerebral endothelium be considered as a unique entity. Cerebral endothelial cells perform several functions vital for brain health. The cerebral vasculature is responsible for protecting the brain from external threats carried in the blood. The endothelial cells are central to this requirement as they form the basis of the blood-brain barrier. The endothelium also regulates fibrinolysis, thrombosis, platelet activation, vascular permeability, metabolism, catabolism, inflammation, and white cell trafficking. Endothelial cells regulate the changes in vascular structure caused by angiogenesis and artery remodeling. Further, the endothelium contributes to vascular tone, allowing proper perfusion of the brain which has high energy demands and no energy stores. In this article, we discuss the basic anatomy and physiology of the cerebral endothelium. Where appropriate, we discuss the detrimental effects of high blood pressure on the cerebral endothelium and the contribution of cerebrovascular disease endothelial dysfunction and dementia. © 2022 American Physiological Society. Compr Physiol 12:3449-3508, 2022.

Diprotin A TFA Exerts Neurovascular Protection in Ischemic Cerebral Stroke

Background

It has been established that the dipeptidyl peptidase-4 (DPP-4) inhibitor Diprotin A TFA can reduce vascular endothelial (VE)-cadherin disruption by inhibiting the increase in cleaved β-catenin in response to hypoxia, thereby protecting the vascular barrier of human umbilical vein endothelial cells. In this study, we sought to investigate the possible effect of Diprotin A TFA on the VE barrier after cerebral ischemic stroke in mice.

Methods

C57BL/6J mice were divided into five groups, namely, (1) sham, (2) stroke, (3) stroke + dimethyl sulfoxide (DMSO), (4) stroke + Diprotin A TFA, and (5) stroke + Diprotin A TFA + XAV-939. First, the cerebral ischemia model was established by photothrombotic ischemia, followed by intraperitoneal injection with Diprotin A TFA and XAV-939 at doses of 70 μg/kg and 40 mg/kg 30 min once in the morning and once in the evening for 3 days. Immunofluorescence staining and Western blot methods were used to analyze the expression of vascular and blood-brain barrier (BBB)-associated molecular markers in the peri-infarct area.

Results

Compared with the vehicle control group, we found that mice injected with Diprotin A TFA exhibited reduced cerebral infarction volume, increased vascular area and length around the brain injury, increased pericyte and basement membrane coverage, upregulated expression of BBB tight junction proteins, and improved their BBB permeability, whereas the group injected with both drug and inhibitor exhibited significantly aggravated vascular injury and BBB permeability.

Conclusion

Diprotin A TFA can reduce VE-cadherin disruption by inhibiting ischemia-hypoxia-induced β-catenin cleavage to protect blood vessels.

rhADAMTS13 reduces oxidative stress by cleaving VWF in ischaemia/reperfusion-induced acute kidney injury

AIMS

Acute kidney injury (AKI), a major health burden, lacks effective therapy. Anti-inflammatory actions of a disintegrin and metalloproteinase with a thrombospondin type 1 motif member 13 (ADAMTS13) may provide a new treatment option for AKI. Along with inflammation, oxidative stress is critical for AKI development, yet the impact of ADAMTS13 on oxidative stress in AKI remains to be fully elucidated.

METHODS

We assess recombinant human ADAMTS13 (rhADAMTS13) actions on oxidative stress in a murine ischaemia/reperfusion (IR) model. Antioxidant stress-enzyme activities, renal morphology, kidney function markers and vascular function of isolated afferent arterioles are quantified.

RESULTS

rhADAMTS13 provided after IR, reduces blood urea nitrogen (BUN) by 33% and serum creatinine (Scr) by 73% in 24 hours post-IR. rhADAMTS13 reduces BUN (40.03 ± 20.34 mmol/L vs 72.35 ± 18.74 mmol/L, P < .01), Scr (75.67 ± 51.19 μmol/L vs 176.17 ± 55.38 μmol/L, P < .01) and proteinuria by 41% in 48 hours post-IR as well. Moreover, rhADAMTS13 administration decreases malondialdehyde (MDA) and increases the activity of antioxidant stress enzymes, and attenuates reactive oxygen species production. rhADAMTS13 also upregulates nuclear factor-erythroid-2-related factor 2/haem oxygenase-1, enhances antioxidant enzymes activity and alleviates endothelial dysfunction. Finally, treatment with rhADAMTS13 mitigates severe functional and morphological injury present in IR mice. Extracellular signal-regulated kinase (ERK) phosphorylation is limited by rhADAMTS13 and PPARγ expression is partly restored in ischaemic kidneys. Co-administration of von Willebrand factor (VWF) impairs rhADAMTS13's antioxidant capacity and its protective role in IR.

CONCLUSION

rhADAMTS13 alleviates renal IR injury through antioxidant effects by cleaving VWF.

An Optimized Purification Design for Extracting Active ADAMTS13 from Conditioned Media

ADAMTS13 is a hemostatic enzyme that breaks down pro-thrombotic ultra-large multimers of von Willebrand factor (VWF). The deficiency of ADAMTS13 increases VWF-mediated thrombogenic potential and may lead to thrombotic thrombocytopenic purpura (TTP). Recently, clinical studies have shown the development of acquired TTP after COVID-19 infection and a correlation between low ADAMTS13 plasma levels and increased mortality. As a result, investigating ADAMTS13 as a potential recombinant therapeutic is of broad interest in the field of hematology. ADAMTS13 is considered challenging to purify in its biologically active state. Current purification methods utilize immobilized metal ions, which can interfere with ADAMTS13 metalloprotease activity. For this reason, we optimized an alternative strategy to isolate milligram quantities of highly active recombinant ADAMTS13 (rADAMTS13) from conditioned media after exogenous expression in human cell line, HEK293. HEK293 cells stably expressing C-terminal V5-His-tagged ADAMTS13 were grown in two parallel systems, culture bottles and flasks, for identifying an optimal cultivation strategy. Subsequently, we employed anion exchange followed by anti-V5-tag affinity chromatography to purify rADAMTS13, and extracted rADAMTS13 of high specific activity while preserving its native post-translational modifications. In addition, this process has been optimized and scaled up to produce active rADAMTS13 at levels sufficient for laboratory-scale structural, enzymatic, and biochemical studies.

The NEDD8-activating enzyme inhibitor MLN4924 reduces ischemic brain injury in mice

Ischemic stroke is a leading cause of death and disability with limited therapies. Neuronal precursor cell-expressed developmentally downregulated protein 8 (NEDD8) is a ubiquitin-like protein that is involved in protein neddylation. The first-in-class anticancer agent called MLN4924 plays a crucial role in suppressing tumorigenesis and attenuating inflammatory responses due to specifically inhibiting NEDD8-activating enzyme. Here, we investigated the potential protective role of MLN4924 after experimental stroke. We showed that the neddylation pathway is overactivated in the brain following cerebral ischemia. Inhibition of neddylation by MLN4924 protects the brain against ischemic injury by attenuating neutrophil extravasation and maintaining blood–brain barrier integrity. Our findings provide insights into the promising treatment with neddylation inhibition for ischemic brain injury.

Blood–brain barrier (BBB) breakdown and inflammation occurring at the BBB have a key, mainly a deleterious role in the pathophysiology of ischemic stroke. Neddylation is a ubiquitylation-like pathway that is critical in various cellular functions by conjugating neuronal precursor cell-expressed developmentally down-regulated protein 8 (NEDD8) to target proteins. However, the roles of neddylation pathway in ischemic stroke remain elusive. Here, we report that NEDD8 conjugation increased during acute phase after ischemic stroke and was present in intravascular and intraparenchymal neutrophils. Inhibition of neddylation by MLN4924, also known as pevonedistat, inactivated cullin-RING E3 ligase (CRL), and reduced brain infarction and improved functional outcomes. MLN4924 treatment induced the accumulation of the CRL substrate neurofibromatosis 1 (NF1). By using virus-mediated NF1 silencing, we show that NF1 knockdown abolished MLN4924-dependent inhibition of neutrophil trafficking. These effects were mediated through activation of endothelial P-selectin and intercellular adhesion molecule-1 (ICAM-1), and blocking antibodies against P-selectin or anti–ICAM-1 antibodies reversed NF1 silencing-induced increase in neutrophil infiltration in MLN4924-treated mice. Furthermore, we found that NF1 silencing blocked MLN4924-afforded BBB protection and neuroprotection through activation of protein kinase C δ (PKCδ), myristoylated alanine-rich C-kinase substrate (MARCKS), and myosin light chain (MLC) in cerebral microvessels after ischemic stroke, and treatment of mice with the PKCδ inhibitor rottlerin reduced this increased BBB permeability. Our study demonstrated that increased neddylation promoted neutrophil trafficking and thus exacerbated injury of the BBB and stroke outcomes. We suggest that the neddylation inhibition may be beneficial in ischemic stroke.

Methylglyoxal Scavengers Attenuate Angiogenesis Dysfunction Induced by Methylglyoxal and Oxygen-Glucose Deprivation

Cerebral endothelial cells play an essential role in brain angiogenesis, and their function has been found to be impaired in diabetes. Methylglyoxal (MG) is a highly reactive dicarbonyl metabolite of glucose formed mainly during glycolysis, and its levels can be elevated in hyperglycemic conditions. MG is a potent precursor of AGEs (advanced glycation end-products). In this study, we investigated if MG can induce angiogenesis dysfunction and whether MG scavengers can ameliorate angiogenesis dysfunction induced by MG. Here, we used cultured human brain microvascular endothelial cells (HBMECs) treated with MG and oxygen-glucose deprivation (OGD) to mimic diabetic stroke in vitro. We also used the MG challenged chicken embryo chorioallantoic membrane (CAM) to study angiogenesis in vivo. Interestingly, administration of MG significantly impaired cell proliferation, cell migration, and tube formation and decreased protein expression of angiogenesis-related factors, which was rescued by three different MG scavengers, glyoxalase 1 (GLO1), aminoguanidine (AG), and N-acetyl cysteine (NAC). In cultured CAM, MG exposure significantly reduced angiogenesis and the angiogenesis-related dysfunction could be attenuated by pretreatment with AG or NAC. Treatment of cultured HBMECs with MG plus OGD increased cellular apoptosis significantly, which could be prevented by exposure to GLO1, AG, or NAC. We also noted that administration of MG increased cellular oxidative stress as measured by reactive oxygen species (ROS) generation, enhanced AGE accumulation, and receptor for advanced glycation end-product (RAGE) expression in the cultured HBMECs, which were partially reversed by GLO1, AG, or NAC. Taken together, our findings demonstrated that GLO1, AG, or NAC administration can ameliorate MG-induced angiogenesis dysfunction, and this can be mainly attributed to attenuated ROS production, reduced cellular apoptosis, and increased levels of angiogenic factors. Overall, this study suggested that GLO1, AG, or NAC may be promising candidate compounds for the treatment of angiogenesis dysfunction caused by hyperglycemia in diabetic ischemic stroke.

Involvement of platelet-derived VWF in metastatic growth of melanoma in the brain

Background

The prognosis of patients with brain metastases (BM) is poor despite advances in our understanding of the underlying pathophysiology. The high incidence of thrombotic complications defines tumor progression and the high mortality rate. We, therefore, postulated that von Willebrand factor (VWF) promotes BM via its ability to induce platelet aggregation and thrombosis.

Methods

We measured the abundance of VWF in the blood and intravascular platelet aggregates of patients with BM, and determined the specific contribution of endothelial and platelet-derived VWF using in vitro models and microfluidics. The relevance for the brain metastatic cascade in vivo was demonstrated in ret transgenic mice, which spontaneously develop BM, and by the intracardiac injection of melanoma cells.

Results

Higher levels of plasma VWF in patients with BM were associated with enhanced intraluminal VWF fiber formation and platelet aggregation in the metastatic tissue and peritumoral regions. Platelet activation triggered the formation of VWF multimers, promoting platelet aggregation and activation, in turn enhancing tumor invasiveness. The absence of VWF in platelets, or the blocking of platelet activation, abolished platelet aggregation, and reduced tumor cell transmigration. Anticoagulation and platelet inhibition consistently reduced the number of BM in preclinical animal models.

Conclusions

Our data indicate that platelet-derived VWF is involved in cerebral clot formation and in metastatic growth of melanoma in the brain. Targeting platelet activation with low-molecular-weight heparins represents a promising therapeutic approach to prevent melanoma BM.

ADAM and ADAMTS disintegrin and metalloproteinases as major factors and molecular targets in vascular malfunction and disease

A Disintegrin and Metalloproteinase (ADAM) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) are two closely related families of proteolytic enzymes. ADAMs are largely membrane-bound enzymes that act as molecular scissors or sheddases of membrane-bound proteins, growth factors, cytokines, receptors and ligands, whereas ADAMTS are mainly secreted enzymes. ADAMs have a pro-domain, and a metalloproteinase, disintegrin, cysteine-rich and transmembrane domain. Similarly, ADAMTS family members have a pro-domain, and a metalloproteinase, disintegrin, and cysteine-rich domain, but instead of a transmembrane domain they have thrombospondin motifs. Most ADAMs and ADAMTS are activated by pro-protein convertases, and can be regulated by G-protein coupled receptor agonists, Ca²⁺ ionophores and protein kinase C. Activated ADAMs and ADAMTS participate in numerous vascular processes including angiogenesis, vascular smooth muscle cell proliferation and migration, vascular cell apoptosis, cell survival, tissue repair, and wound healing. ADAMs and ADAMTS also play a role in vascular malfunction and cardiovascular diseases such as hypertension, atherosclerosis, coronary artery disease, myocardial infarction, heart failure, peripheral artery disease, and vascular aneurysm. Decreased ADAMTS13 is involved in thrombotic thrombocytopenic purpura and microangiopathies. The activity of ADAMs and ADAMTS can be regulated by endogenous tissue inhibitors of metalloproteinases and other synthetic small molecule inhibitors. ADAMs and ADAMTS can be used as diagnostic biomarkers and molecular targets in cardiovascular disease, and modulators of ADAMs and ADAMTS activity may provide potential new approaches for the management of cardiovascular disorders.

Placenta Percreta Presents with Neoangiogenesis of Arteries with Von Willebrand Factor-Negative Endothelium

In placenta percreta cases, large vessels are present on the precrete surface area. As these vessels are not found in normal placentation, we examined their histological structure for features that might explain the pathogenesis of neoangiogenesis induced by placenta accreta spectrum disorders (PAS). In two patients with placenta percreta (FIGO grade 3a) of the anterior uterine wall, one strikingly large vessel of 2 cm length was excised. The samples were formalin fixed and paraffin-embedded. Gomori trichrome staining was used to evaluate the muscular layers and Weigert-Van Gieson staining for elastic fibers. Immunohistochemical staining of the vessel endothelium was performed for Von Willebrand factor (VWF), platelet endothelial cell adhesion molecule (CD31), Ephrin B2, and EPH receptor B4. The structure of the vessel walls appeared artery-like. The vessel of patient one further exhibited an unorderly muscular layer and a lack of elastic laminae, whereas these features appeared normal in the vessel of the other patient. The endothelium of both vessels stained VWF-negative and CD31-positive. In conclusion, this study showed VWF-negative vessel endothelia of epiplacental arteries in placenta accreta spectrum. VWF is known to regulate artery formation, as the absence of VWF has been shown to cause enhanced vascularization. Therefore, we suppose that PAS provokes increased vascularization through suppression of VWF. This process might be associated with the immature vessel architecture as found in one of the vessels and Ephrin B2 and EPH receptor B4 negativity of both artery-like vessels. The underlying pathomechanism needs to be evaluated in a greater set of patients.

Von Willebrand factor exerts hepatoprotective effects in acute but not chronic cholestatic liver injury in mice

Acute and chronic liver disease are associated with substantial alterations in the hemostatic system, including elevated levels of the platelet-adhesive protein von Willebrand factor (VWF). Carbon tetrachloride-induced liver fibrosis is reduced in VWF-deficient mice, but it is unclear if VWF plays a pathologic role in all settings of liver fibrosis. Indeed, several studies suggest an anti-fibrotic role for components of the hemostatic system, including platelets, in experimental settings of bile duct fibrosis. However, the role of VWF in this specific pathology has not been examined. We tested the hypothesis that VWF exerts hepatoprotective effects in experimental bile duct injury. Wild-type and VWF-deficient (VWF^-/-) mice were challenged with the bile duct toxicant alpha-naphthylisothiocyanate (ANIT) and the impact of VWF deficiency on acute cholestatic liver injury and chronic liver fibrosis was determined. Acute ANIT (60 mg/kg, po)-induced cholestatic liver injury was associated with increased VWF plasma antigen and activity levels. VWF deficiency enhanced ANIT-induced hepatocellular injury, evidenced by increased plasma ALT activity and area of hepatocellular necrosis. Surprisingly, platelet accumulation within necrotic areas was increased in ANIT-challenged VWF^-/- mice compared to wild-type mice. Compared to acute ANIT challenge, hepatic platelet accumulation was modest and appeared to be VWF-dependent in mice exposed to ANIT diet (0.05 %) for 6 weeks. However, contrasting the role of VWF after acute ANIT challenge, VWF deficiency did not impact biliary fibrosis induced by chronic ANIT exposure. The results suggest that VWF plays dichotomous roles in experimental acute and chronic ANIT-induced cholestatic liver injury.

Role of Neurons and Glia Cells in Wound Healing as a Novel Perspective Considering Platelet as a Conventional Player

Wound healing is a complex physiological process in which the damaged or injured tissue is replaced or regenerated by new cells or existing cells respectively in their synthesized and secreted matrices. Several cells modulate the process of wound healing including macrophages, fibroblasts, and keratinocytes. Apart from these cells, platelet has been considered as a major cellular fragment to be involved in wound healing at several stages by secreting its granular contents including growth factors, thus resulting in coagulation, inflammation, and angiogenesis. A distant cell, which is gaining significant attention nowadays due to its resemblance with platelet in several aspects, is the neuron. Not only neurons but also glia cells are also confirmed to regulate wound healing at different stages in an orchestrated manner. Furthermore, these neurons and glia cells mediate wound healing inducing tissue repair and regeneration apart from hemostasis, angiogenesis, and inflammation by secreting various growth factors, coagulation molecules, immunomodulatory molecules as well as neurohormones, neuropeptides, and neurotrophins. Therefore, in wound healing platelets, neurons and glia cells not only contribute to tissue repair but are also responsible for establishing the wound microenvironment, thus affecting the proliferation of immune cells, fibroblast, and keratinocytes. Here in this review, we will enlighten the physiological roles of neurons and glia cells in coordination with platelets to understand various cellular and molecular mechanism in brain injury and associated neurocognitive impairments.

Microneedle-mediated vascular endothelial growth factor delivery promotes angiogenesis and functional recovery after stroke

Ischemic stroke is still the major cause of disability worldwide. Although vascular endothelial growth factor (VEGF) is able to promote both angiogenesis and functional recovery, its use is limited by needle-induced injury, nonhomogenous VEGF distribution, and limited VEGF retention in the brain after intracranial or intravenous injection. Here, we first present a gelatin methacryloyl (GelMA) microneedle (MN)-based platform for the sustained and controlled local delivery of an adeno-associated virus (AAV) expressing human VEGF (AAV-VEGF) that achieves homogenous distribution and high transfection efficiency in ischemic brains. An ischemic stroke model was established in adult rats, and MNs loaded with AAV-VEGF were epicortically inserted into both the ischemic core and penumbra of these rats one day after the onset of ischemia. One week later, the inflammatory response and microneedle biocompatibility were assessed by enzyme-linked immunosorbent assay (ELISA) and immunofluorescence. Eight weeks later, angiogenesis and neural stem cell proliferation and migration were assessed. GelMA MN implantation did not elicit an obvious inflammatory response and had good biocompatibility in the brain. AAV-green fluorescent protein (GFP)-loaded MNs could achieve successful transfection and homogeneous distribution in the brain cortex three weeks postoperatively. MNs loaded with AAV-VEGF increased VEGF expression and enhanced functional angiogenesis and neurogenesis. In summary, MNs might emerge as a promising platform for delivering various therapeutics to treat ischemic stroke and repair other neurologically diseased tissues.

Delayed rFGF21 Administration Improves Cerebrovascular Remodeling and White Matter Repair After Focal Stroke in Diabetic Mice

Type 2 diabetes mellitus (T2DM) is a major comorbidity exacerbating ischemic brain injury and impairing post-stroke recovery. Our previous study suggested that recombinant human fibroblast growth factor (rFGF) 21 might be a potent therapeutic targeting multiple aspects of pathophysiology in T2DM stroke. This study aims to evaluate the potential effects of rFGF21 on cerebrovascular remodeling after T2DM stroke. Permanent distal middle cerebral artery occlusion was performed in heterozygous non-diabetic db/ + and homozygous diabetic db/db mice. Daily rFGF21 administration was initiated 1 week after stroke induction and maintained for up to 2 weeks thereafter. Multiple markers associated with post-stroke recovery, including angiogenesis, oligodendrogenesis, white matter integrity, and neurogenesis, were assessed up to 3 weeks after stroke. Our results showed an impairment in post-stroke vascular remodeling under T2DM condition, reflected by the decreased expression of trophic factors in brain microvessels and impairments of angiogenesis. The defected cerebrovascular remodeling was accompanied by the decreased oligodendrogenesis and neurogenesis. However, delayed rFGF21 administration normalized post-stroke hyperglycemia and improved neurological outcomes, which may partially be via the promotion of pro-angiogenic trophic factor expression in brain microvessels and cerebrovascular remodeling. The better cerebrovascular remodeling may also contribute to oligodendrogenesis, white matter integrity, and neurogenesis after T2DM stroke. Therefore, delayed rFGF21 administration may improve neurological outcomes in T2DM stroke mice, at least in part by normalizing the metabolic abnormalities and promoting cerebrovascular remodeling and white matter repair.

Neutrophil extracellular traps promote tPA-induced brain hemorrhage via cGAS in mice with stroke

Intracerebral hemorrhage associated with thrombolytic therapy with tissue plasminogen activator (tPA) in acute ischemic stroke continues to present a major clinical problem. Here, we report that infusion of tPA resulted in a significant increase in markers of neutrophil extracellular traps (NETs) in the ischemic cortex and plasma of mice subjected to photothrombotic middle cerebral artery occlusion. Peptidylarginine deiminase 4 (PAD4), a critical enzyme for NET formation, is also significantly upregulated in the ischemic brains of tPA-treated mice. Blood-brain barrier (BBB) disruption after ischemic challenge in an in vitro model of BBB was exacerbated after exposure to NETs. Importantly, disruption of NETs by DNase I or inhibition of NET production by PAD4 deficiency restored tPA-induced loss of BBB integrity and consequently decreased tPA-associated brain hemorrhage after ischemic stroke. Furthermore, either DNase I or PAD4 deficiency reversed tPA-mediated upregulation of the DNA sensor cyclic GMP-AMP (cGAMP) synthase (cGAS). Administration of cGAMP after stroke abolished DNase I-mediated downregulation of the STING pathway and type 1 interferon production and blocked the antihemorrhagic effect of DNase I in tPA-treated mice. We also show that tPA-associated brain hemorrhage after ischemic stroke was significantly reduced in cGas-/- mice. Collectively, these findings demonstrate that NETs significantly contribute to tPA-induced BBB breakdown in the ischemic brain and suggest that targeting NETs or cGAS may ameliorate thrombolytic therapy for ischemic stroke by reducing tPA-associated hemorrhage.

Circulating Extracellular Vesicle Proteins and MicroRNA Profiles in Subcortical and Cortical-Subcortical Ischaemic Stroke

In order to investigate the role of circulating extracellular vesicles (EVs), proteins, and microRNAs as damage and repair markers in ischaemic stroke depending on its topography, subcortical (SC), and cortical-subcortical (CSC) involvement, we quantified the total amount of EVs using an enzyme-linked immunosorbent assay technique and analysed their global protein content using proteomics. We also employed a polymerase chain reaction to evaluate the circulating microRNA profile. The study included 81 patients with ischaemic stroke (26 SC and 55 CSC) and 22 healthy controls (HCs). No differences were found in circulating EV levels between the SC, CSC, and HC groups. We detected the specific expression of C1QA and Casp14 in the EVs of patients with CSC ischaemic stroke and the specific expression of ANXA2 in the EVs of patients with SC involvement. Patients with CSC ischaemic stroke showed a lower expression of miR-15a, miR-424, miR-100, and miR-339 compared with those with SC ischaemic stroke, and the levels of miR-339, miR-100, miR-199a, miR-369a, miR-424, and miR-15a were lower than those of the HCs. Circulating EV proteins and microRNAs from patients with CSC ischaemic stroke could be considered markers of neurite outgrowth, neurogenesis, inflammation process, and atherosclerosis. On the other hand, EV proteins and microRNAs from patients with SC ischaemic stroke might be markers of an anti-inflammatory process and blood–brain barrier disruption reduction.

Serum and cerebrospinal fluid host proteins indicate stroke in children with tuberculous meningitis

Introduction

Stroke is a common complication in children with tuberculous meningitis (TBM). Host proteins may give us insight into the mechanisms of stroke in TBM and serve as biomarkers for detection of stroke, however, they have not been widely explored. In this study, we compared the concentrations of cerebrospinal fluid (CSF) and serum proteins between children who had TBM-related stroke and children with TBM without stroke.

Methods

We collected CSF and serum from 47 children consecutively admitted to the Tygerberg Academic Hospital in Cape Town, South Africa between November 2016, and November 2017, on suspicion of having TBM. A multiplex platform was used to measure the concentrations of 69 host proteins in CSF and serum from all study participants.

Results

After classification of study participants, 23 (48.9%) out of the 47 study participants were diagnosed with TBM, of which 14 (60.9%) demonstrated radiological arterial ischemic infarction. The levels of lipocalin-2, sRAGE, IP-10/ CXCL10, sVCAM-1, MMP-1, and PDGF-AA in CSF samples and the levels of D-dimer, ADAMTS13, SAA, ferritin, MCP-1/ CCL2, GDF-15 and IL-13 in serum samples were statistically different between children who had TBM-related stroke and children with TBM without stroke. After correcting for multiple testing, only the levels of sVCAM-1, MMP-1, sRAGE, and IP-10/ CXCL10 in CSF were statistically different between the two groups. CSF and serum protein biosignatures indicated stroke in children diagnosed with TBM with up to 100% sensitivity and 88.9% specificity.

Conclusion

Serum and CSF proteins may serve as biomarkers for identifying individuals with stroke amongst children diagnosed with TBM at admission and may guide us to understand the biology of stroke in TBM. This was a pilot study, and thus further investigations in larger studies are needed.

ADAMTS13 inhibits oxidative stress and ameliorates progressive chronic kidney disease following ischaemia/reperfusion injury

AIMS

Reduced A Disintegrin And Metalloproteinase with a ThromboSpondin type 1 motif member 13 (ADAMTS13) levels are observed in kidney disease. We test whether recombinant human ADAMTS13 (rhADAMTS13) mitigates renal injury in chronic kidney disease (CKD) and the potential mechanisms.

METHODS

CKD was established 3 months after ischaemia/reperfusion (IR). ADAMTS13 and von Willebrand factor (vWF) levels, renal function and morphological changes were analysed. Afferent arteriolar responses to angiotensin II (Ang II) and acetylcholine (ACh) were measured. Oxidative stress-related molecules were detected.

RESULTS

Higher vWF and lower ADAMTS13 levels were observed in CKD mice, which were markedly attenuated by rhADAMTS13. rhADAMTS13 alleviated renal dysfunction, as documented by decreased blood urea nitrogen (BUN), serum creatinine, kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) levels in CKD mice. Moreover, rhADAMTS13 attenuated transforming growth factor (TGF)-β1/Smad3 activation. Plasma vWF: ADAMTS13 ratio showed positive correlations with malondialdehyde (MDA), hydrogen peroxide (H₂ O₂ ) and proteinuria, and correlated inversely with superoxide dismutase (SOD) and catalase (CAT). Finally, rhADAMTS13 inhibited reactive oxygen species (ROS) levels and improved microvascular functional disorders, accompanied by the inhibition of glycogen synthase kinase (GSK) 3β hyperactivity and upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) expression.

CONCLUSIONS

Acute kidney injury (AKI) reduces the expression of ADAMTS13 that contributes to progressive CKD, microvascular dysfunction, oxidative stress, inhibition of Nrf2 activity and renal histopathological damage. All of which can be alleviated by administration of rhADAMTS13.

Diverse activities of von Willebrand factor in traumatic brain injury and associated coagulopathy

Traumatic brain injury (TBI) is a leading cause of death and disability. Patients with isolated TBI lose a limited amount of blood to primary injury, but they often develop secondary coagulopathy, resulting in delayed or recurrent intracranial and intracerebral hematoma. TBI-induced coagulopathy is closely associated with poor outcomes for these patients, including death. This secondary coagulopathy is consumptive in nature, involving not only brain-derived molecules, coagulation factors, and platelets, but also endothelial cells in a complex process now called blood failture. A key question is how a localized injury to the brain is rapidly disseminated to affect systemic hemostasis that is not directly affected the way it is in trauma to the body and limbs, especially with hemorrhagic shock. Increasing evidence suggests that the adhesive ligand von Willebrand factor (VWF), which is synthesized in and released from endothelial cells, plays a paradoxical role in both facilitating local hemostasis at the site of injury and also propagating TBI-induced endotheliopathy and coagulopathy systemically. This review discusses recent progress in understanding these diverse activities of VWF and the knowledge gaps in defining their roles in TBI and associated coagulopathy.

Biomarkers of Unfavorable Outcome in Acute Ischemic Stroke Patients with Successful Recanalization by Endovascular Thrombectomy

<b><i>Background:</i></b> We aimed to identify plasma markers of unfavorable outcomes for patients with acute ischemic stroke (AIS) after recanalization by endovascular thrombectomy (EVT). <b><i>Methods:</i></b> From November 2017 to May 2019, we prospectively collected 61 AIS patients due to anterior large vessel occlusion who achieved recanalization by EVT. Plasma samples were obtained between 18 and 24 h after recanalization. Unfavorable outcomes included futile recanalization at 90 days and overall early complications within 7 days after EVT. <b><i>Results:</i></b> After adjustment for age and initial National Institute of Health Stroke Scale (NIHSS), matrix metalloproteinase-9 (MMP-9), tenascin-C, thioredoxin, ADAMTS13, and gelsolin were independently associated with both futile recanalization and overall early complications significantly (all <i>p</i> &#x3c; 0.05), while C-reactive protein (CRP) was independently associated with overall early complications (<i>p</i> = 0.031) but at the limit of significance for futile recanalization (<i>p</i> = 0.051). The baseline clinical model (BCM) (including age and initial NIHSS) demonstrated discriminating ability to indicate futile recanalization (area under the curve [AUC] 0.807, 95% confidence interval [CI] 0.693–0.921) and overall early complications (AUC 0.749, 95% CI 0.611–0.887). BCM+MMP-9+thioredoxin enhanced discrimination (AUC 0.908, 95% CI 0.839–0.978, <i>p</i> = 0.043) and reclassification (net reclassification improvement [NRI] 67.2%, <i>p</i> &#x3c; 0.001) to indicate futile recanalization. With respect to overall early complications, BCM+MMP-9+tenascin-C, BCM+MMP-9+CRP, BCM+MMP-9+ADAMTS13, BCM+tenascin-C+ADAMTS13, and BCM+CRP+ADAMTS13, all improved discrimination (AUC [95% CI]: 0.868 [0.766–0.970], 0.882 [0.773–0.990], 0.886 [0.788–0.984], 0.880 [0.783–0.977], and 0.863 [0.764–0.962], respectively, all <i>p</i> &#x3c; 0.05 by the DeLong method) and reclassification (NRI 59.1%, 71.8%, 51.1%, 67.4%, and 38.3%, respectively, all <i>p</i> &#x3c; 0.05). <b><i>Conclusions:</i></b> The increased levels of MMP-9, tenascin-C, CRP, thioredoxin, and decreased levels of ADAMTS13 and gelsolin were independent predictors of futile recanalization in AIS patients after recanalization by EVT.

Structural and Functional Remodeling of the Brain Vasculature Following Stroke

Maintenance of cerebral blood vessel integrity and regulation of cerebral blood flow ensure proper brain function. The adult human brain represents only a small portion of the body mass, yet about a quarter of the cardiac output is dedicated to energy consumption by brain cells at rest. Due to a low capacity to store energy, brain health is heavily reliant on a steady supply of oxygen and nutrients from the bloodstream, and is thus particularly vulnerable to stroke. Stroke is a leading cause of disability and mortality worldwide. By transiently or permanently limiting tissue perfusion, stroke alters vascular integrity and function, compromising brain homeostasis and leading to widespread consequences from early-onset motor deficits to long-term cognitive decline. While numerous lines of investigation have been undertaken to develop new pharmacological therapies for stroke, only few advances have been made and most clinical trials have failed. Overall, our understanding of the acute and chronic vascular responses to stroke is insufficient, yet a better comprehension of cerebrovascular remodeling following stroke is an essential prerequisite for developing novel therapeutic options. In this review, we present a comprehensive update on post-stroke cerebrovascular remodeling, an important and growing field in neuroscience, by discussing cellular and molecular mechanisms involved, sex differences, limitations of preclinical research design and future directions.