Inflammation, von Willebrand factor, and ADAMTS13

Von Willebrand Factor and Platelet Levels before Conditioning Chemotherapy Indicate Bone Marrow Regeneration following Autologous Hematopoietic Stem Cell Transplantation

Autologous hematopoietic stem cell transplantation (HSCT) is often complicated by hemostatic and thrombotic events associated with endothelial cell injury. Thrombotic complications are affected by a disturbed balance between platelets, circulating von Willebrand factor (VWF), and its specific protease, ADAMTS13. HSCT-associated endothelial dysfunction, impaired hemostasis, and inflammation are interrelated processes, and research on the complex interplay of conditioning regimens from engraftment to bone marrow regeneration remains intensive. This prospective observational study comparing lymphoma and multiple myeloma (MM) patients who underwent autologous HSCT explored how platelet count, VWF level, ADAMTS13 activity, and C-reactive protein (CRP) level as potential markers (1) vary in response to therapy, (2) differ between the 2 groups, and (3) correlate with the remission state at 100 days after HSCT. We correlated the quantitative changes in platelet count and levels of VWF, ADAMTS13, and CRP with one another during HSCT and in the remission state in 45 patients with lymphoma and 59 patients with MM who underwent autologous HSCT between 2010 and 2013 at the University of Debrecen. Samples were collected at the start of conditioning chemotherapy, on the day of stem cell transplantation, and at 5, 11, and 100 days following HSCT. CRP levels peaked when platelet counts dropped to a minimum, and these changes were much more pronounced in the lymphoma group. VWF level was the highest, with lower ADAMTS13 activity, at platelet engraftment in both patient groups equally. Diagnostic evidence indicative of thrombotic complications was not found. In the lymphoma group, VWF level prior to conditioning had statistically significant correlations with platelet count, CRP level, and hemoglobin concentration at the time of bone marrow regeneration (P < .001) and during the remission state (P = .034). In the MM group, platelet count before conditioning was correlated with platelet count (P < .001) and white blood cell count (P = .012) at the time of bone marrow regeneration. The statistically significant correlation of the markers at the time of bone marrow regeneration with the preconditioning VWF levels in lymphoma and with the preconditioning platelet counts in MM might indicate the clinical significance of the bone marrow niches of arterioles and megakaryocytes, respectively, where the stem cells are located and regulated. Because preconditioning VWF levels are associated with remission after HSCT in lymphoma patients, VWF should be screened before conditioning, along with the markers used in HSCT protocols, to optimize personalized treatment and reduce therapeutic risks.

Microvascular lung injury and endoplasmic reticulum stress in systemic lupus erythematosus-associated alveolar hemorrhage and pulmonary vasculitis

Human COPA mutations affecting retrograde Golgi-to-endoplasmic reticulum (ER) protein transport cause diffuse alveolar hemorrhage (DAH) and ER stress ("COPA syndrome"). Patients with SLE also can develop DAH. C57BL/6 (B6) mice with pristane-induced lupus develop monocyte-dependent DAH indistinguishable from human DAH, whereas BALB/c mice are resistant. We examined Copa and ER stress in pristane-induced lupus. Copa expression, ER stress, vascular injury, and apoptosis were assessed in mice and COPA was quantified in blood from patients with SLE. Copa mRNA and protein expression were impaired in B6 mice with pristane-induced DAH, but not in pristane-treated BALB/c mice. An ER stress response (increased Hsp5a/BiP, Ddit3/CHOP, Eif2a, and spliced Xbp1) was seen in lungs from pristane-treated B6, but not BALB/c, mice. Resistance of BALB/c mice to DAH was overcome by treating them with low-dose thapsigargin plus pristane. CB6F1 mice did not develop DAH or ER stress, suggesting that susceptibility was recessive. Increased pulmonary expression of von Willebrand factor (Vwf), a marker of endothelial injury, and the chemokine Ccl2 in DAH suggested that pristane promotes lung microvascular injury and monocyte recruitment. Consistent with that possibility, lung endothelial cells and infiltrating bone marrow-derived cells from pristane-treated B6 mice expressed BiP and showed evidence of apoptosis (annexin-V and activated caspase-3 staining). COPA expression also was low in patients with SLE with lung involvement. Pristane-induced DAH may be initiated by endothelial injury, resulting in ER stress, apoptosis of lung endothelial cells, and recruitment of myeloid cells that propagate lung injury. The pathogenesis of DAH in SLE and COPA syndrome may overlap.

Nanoenzyme engineered neutrophil-derived exosomes attenuate joint injury in advanced rheumatoid arthritis via regulating inflammatory environment

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovitis and destruction of cartilage, promoted by sustained inflammation. However, current treatments remain unsatisfactory due to lacking of selective and effective strategies for alleviating inflammatory environments in RA joint. Inspired by neutrophil chemotaxis for inflammatory region, we therefore developed neutrophil-derived exosomes functionalized with sub-5 nm ultrasmall Prussian blue nanoparticles (uPB-Exo) via click chemistry, inheriting neutrophil-targeted biological molecules and owning excellent anti-inflammatory properties. uPB-Exo can selectively accumulate in activated fibroblast-like synoviocytes, subsequently neutralizing pro-inflammatory factors, scavenging reactive oxygen species, and alleviating inflammatory stress. In addition, uPB-Exo effectively targeted to inflammatory synovitis, penetrated deeply into the cartilage and real-time visualized inflamed joint through MRI system, leading to precise diagnosis of RA in vivo with high sensitivity and specificity. Particularly, uPB-Exo induced a cascade of anti-inflammatory events via Th17/Treg cell balance regulation, thereby significantly ameliorating joint damage. Therefore, nanoenzyme functionalized exosomes hold the great potential for enhanced treatment of RA in clinic.

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uPB-Exo were firstly developed by combining NE-Exo with sub-5 nm ultrasmall PB nanoparticles via click chemistry.

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uPB-Exo selectively targeted inflamed joints via neutrophil-targeted biological molecules inherited from neutrophils.

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uPB-Exo accumulated in active FLS, and eventually scavenged reactive oxygen species and alleviated inflammatory stress.

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uPB-Exo induced a cascade of anti-inflammatory events via Th17/Treg cell balance regulation, thereby significantly ameliorating joint damage.

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uPB-Exo, as a drug free therapeutical agent, holds the great potential for enhanced treatment of RA in clinic.

Endothelial dysfunction markers and immune response indices in cosmonauts' blood after long-duration space flights

Space flight factors are known to cause a malfunction in the human immune system and lead to damage to blood vessels. The hemostatic function of endothelium during space missions and its interaction with human immunity has not been determined so far. In this work, we investigated the markers of endothelial activation and damage (plasma concentrations of soluble thrombomodulin fraction (sTM), von Willebrand factor (vWF), highly sensitive C-reactive protein (hs-CRP)), as well as the level of D-dimer and compared them to the immunological parameters characterizing the state of human humoral and cellular immunity. The immune status of long-duration ISS crewmembers was assessed by whole-blood testing, and comprehensive postflight immune assessment included the analysis of leukocyte distribution. Flow cytometry was applied to determine the absolute counts and the percentage of lymphocyte subsets: B cells (CD19⁺), T cells (CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺), NK cells (CD3^-CD16⁺CD56⁺, CD11b⁺CD56⁺), and activated subsets (CD3⁺CD25⁺ and CD3⁺HLA-DR⁺). The in vitro basal cytokine production was investigated in whole blood cell culture. The cytokines IFN-gamma, IL-1-beta, IL-4, IL-6, IL-10, IL-18, and TNF-alpha were measured in plasma and the 24-h supernatants by a sensitive enzyme-linked immunosorbent assay. A significant increase in the plasma levels of vWF and hs-CRP and a decrease in the concentration of sTM after spaceflights were detected. Divergent changes in the parameters characterizing the state of the immune system were observed. We propose that the changes revealed may lead to an increase in the procoagulant activity of blood plasma, suppression of protein C activation and thrombin inhibition, as well as to an increase in the adhesive-aggregate potential of platelets, especially in case of changes in the rheological characteristics of blood flow during re-adaptation to ground conditions. We also speculate that the immune system might play an important role in vessel damage during long-duration missions.

Regulation of VWF (Von Willebrand Factor) in Inflammatory Thrombosis

Increasing evidence indicates that inflammation promotes thrombosis via a VWF (von Willebrand factor)-mediated mechanism. VWF plays an essential role in maintaining the balance between blood coagulation and bleeding, and inflammation can lead to aberrant regulation. VWF is regulated on a transcriptional and (post-)translational level, and its secretion into the circulation captures platelets upon endothelial activation. The significant progress that has been made in understanding transcriptional and translational regulation of VWF is described in this review. First, we describe how VWF is regulated at the transcriptional and post-translational level with a specific focus on the influence of inflammatory and immune responses. Next, we describe how changes in regulation are linked with various cardiovascular diseases. Recent insights from clinical diseases provide evidence for direct molecular links between inflammation and thrombosis, including atherosclerosis, chronic thromboembolic pulmonary hypertension, and COVID-19. Finally, we will briefly describe clinical implications for antithrombotic treatment.

Prognostic value of von Willebrand factor and ADAMTS13 in patients with COVID-19: A systematic review and meta-analysis

BACKGROUND

Endotheliopathy and coagulopathy appear to be the main causes for critical illness and death in patients with coronavirus disease 2019 (COVID-19). The adhesive ligand von Willebrand factor (VWF) has been involved in immunothrombosis responding to endothelial injury. Here, we reviewed the current literature and performed meta-analyses on the relationship between both VWF and its cleaving protease ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13) with the prognosis of COVID-19.

METHODS

We searched MEDLINE, Cochrane Library, Web of Science, and EMBASE databases from inception to 4 March 2022 for studies analyzing the relationship between VWF-related variables and composite clinical outcomes of patients with COVID-19. The VWF-related variables analyzed included VWF antigen (VWF:Ag), VWF ristocetin cofactor (VWF:Rco), ADAMTS13 activity (ADAMTS13:Ac), the ratio of VWF:Ag to ADAMTS13:Ac, and coagulation factor VIII (FVIII). The unfavorable outcomes were defined as mortality, intensive care unit (ICU) admission, and severe disease course. We used random or fixed effects models to create summary estimates of risk. Risk of bias was assessed based on the principle of the Newcastle-Ottawa Scale.

RESULTS

A total of 3764 patients from 40 studies were included. The estimated pooled means indicated increased plasma levels of VWF:Ag, VWF:Rco, and VWF:Ag/ADAMTS13:Ac ratio, and decreased plasma levels of ADAMTS13:Ac in COVID-19 patients with unfavorable outcomes when compared to those with favorable outcomes (composite outcomes or subgroup analyses of non-survivor versus survivor, ICU versus non-ICU, and severe versus non-severe). In addition, FVIII were higher in COVID-19 patients with unfavorable outcomes. Subgroup analyses indicated that FVIII was higher in patients admitting to ICU, while there was no significant difference between non-survivors and survivors.

CONCLUSIONS

The imbalance of the VWF-ADAMTS13 axis (massive quantitative and qualitative increases of VWF with relative deficiency of ADAMTS13) is associated with poor prognosis of patients with COVID-19.

Hereditary thrombotic thrombocytopenic purpura and COVID-19: Impacts of vaccination and infection in this rare disease

Introduction

Severe COVID-19 is associated with an important increase of von Willebrand factor and mild lowering of ADAMTS13 activity that may, in the presence of a strong inflammatory reaction, increase the risk of acute thrombotic thrombocytopenic purpura (TTP). Although acute episodes of immune-mediated TTP associated with COVID-19 or SARS-CoV-2 vaccination have been reported, data about clinical evolution of hereditary TTP (hTTP) during the pandemic are scarce.

Method

We conducted a survey among adult patients of the International Hereditary TTP Registry about SARS-CoV-2 vaccination, COVID-19, and occurrence of acute hTTP episodes.

Results

Of 122 adult hTTP patients invited to participate, 86 (70.5%) responded. Sixty-five had been vaccinated (75.6%), of which 14 had received in addition a booster, resulting in 139 individual vaccine shots. Although vaccinations in patients on plasma prophylaxis were done within 1 week of the last plasma infusion, all 23 patients treated with plasma on demand were vaccinated without prior plasma infusions. One patient on uninterrupted weekly plasma infusions presented within 3 days from his second vaccination with neurological symptoms and computed tomography scan 9 days later showed subacute ischemic/hemorrhagic frontal lobe infarction. A second male patient developed acute myocarditis after his second dose of mRNA-1273 vaccine. Twelve (14%) patients had COVID-19, associated with an acute hTTP episode in three of them: one patient had a transient ischemic attack, one a stroke, and a pregnant woman was hospitalized to intensify plasma treatment.

Discussion

The risk of an acute episode triggered by COVID-19 seems higher than following vaccination in hTTP patients, who can be safely vaccinated against SARS-CoV-2.

Involvement of Inflammation and Its Resolution in Disease and Therapeutics

Inflammation plays a critical role in the response to and survival from injuries and/or infections. It occurs in two phases: initiation and resolution; however, when these events do not resolve and persist over time, the inflammatory response becomes chronic, prompting diseases that affect several systems and organs, such as the vasculature and the skin. Here, we reviewed inflammation that occurs in selected infectious and sterile pathologies. Thus, the immune processes induced by bacterial sepsis as well as T. cruzi and SARS-CoV-2 infections are shown. In addition, vaccine adjuvants as well as atherosclerosis are revised as examples of sterile-mediated inflammation. An example of the consequences of a lack of inflammation resolution is given through the revision of wound healing and chronic wounds. Then, we revised the resolution of the latter through advanced therapies represented by cell therapy and tissue engineering approaches, showing how they contribute to control chronic inflammation and therefore wound healing. Finally, new pharmacological insights into the management of chronic inflammation addressing the resolution of inflammation based on pro-resolving mediators, such as lipoxin, maresin, and resolvins, examining their biosynthesis, biological properties, and pharmacokinetic and pharmaceuticals limitations, are given. We conclude that resolution pharmacology and advanced therapies are promising tools to restore the inflammation homeostasis.

Thromboinflammation: From Atherosclerosis to COVID-19

The activating interplay of thrombosis and inflammation (thromboinflammation) has been established as a major underlying pathway, driving not only cardiovascular disease but also autoimmune disease and most recently, COVID-19. Throughout the years, innate immune cells have emerged as important modulators of this process. As the most abundant white blood cell in humans, neutrophils are well-positioned to propel thromboinflammation. This includes their ability to trigger an organized cell death pathway with the release of decondensed chromatin structures called neutrophil extracellular traps. Decorated with histones and cytoplasmic and granular proteins, neutrophil extracellular traps exert cytotoxic, immunogenic, and prothrombotic effects accelerating disease progression. Distinct steps leading to extracellular DNA release (NETosis) require the activities of PAD4 (protein arginine deiminase 4) catalyzing citrullination of histones and are supported by neutrophil inflammasome. By linking the immunologic function of neutrophils with the procoagulant and proinflammatory activities of monocytes and platelets, PAD4 activity holds important implications for understanding the processes that fuel thromboinflammation. We will also discuss mechanisms whereby vascular occlusion in thromboinflammation depends on the interaction of neutrophil extracellular traps with ultra-large VWF (von Willebrand Factor) and speculate on the importance of PAD4 in neutrophil inflammasome assembly and neutrophil extracellular traps in thromboinflammatory diseases including atherosclerosis and COVID-19.

Identification of Endoplasmic Reticulum Stress-Related Biomarkers of Periodontitis Based on Machine Learning: A Bioinformatics Analysis

Objective

To screen for potential endoplasmic reticulum stress- (ERS-) related biomarkers of periodontitis using machine learning methods and explore their relationship with immune cells.

Methods

Three datasets of periodontitis (GSE10334, GES16134, and GES23586) were obtained from the Gene Expression Omnibus (GEO), and the samples were randomly assigned to the training set or the validation set. ERS-related differentially expressed genes (DEGs) between periodontitis and healthy periodontal tissues were screened and analyzed for GO, KEGG, and DO enrichment. Key DEGs were screened by two machine learning algorithms, LASSO regression and support vector machine-recursive feature elimination (SVM-RFE); then, the potential biomarkers were identified through validation. The infiltration of immune cells of periodontitis was calculated using the CIBERSORT algorithm, and the correlation between immune cells and potential biomarkers was specifically analyzed through the Spearman method.

Results

We obtained 36 ERS-related DEGs of periodontitis from the training set, from which 11 key DEGs were screened by further machine learning. SERPINA1, ERLEC1, and VWF showed high diagnostic values (AUC > 0.85), so they were considered as potential biomarkers for periodontitis. According to the results of the immune cell infiltration analysis, these three potential biomarkers showed marked correlations with plasma cells, neutrophils, resting dendritic cells, resting mast cells, and follicular helper T cells.

Conclusions

Three ERS-related genes, SERPINA1, ERLEC1, and VWF, showed valuable biomarker potential for periodontitis, which provide a target base for future studies on early diagnosis and treatment of periodontitis.

High levels of von Willebrand factor with reduced specific activities in hospitalized patients with or without COVID-19

The COVID-19 pandemic is often accompanied by severe respiratory illness and thrombotic complications. Von Willebrand Factor (VWF) levels are highly elevated in this condition. However, limited data are available on the qualitative activity of VWF in COVID-19. We measured plasma VWF levels quantitatively (VWF antigen) and qualitatively (ristocetin-induced platelet agglutination, glycoprotein IbM (GPIbM) binding, and collagen binding). Consistent with prior reports, VWF antigen levels were significantly elevated in hospitalized patients with or without COVID-19. The GPIbM and collagen binding activity-to-antigen ratios were significantly reduced, consistent with qualitative changes in VWF in COVID-19. Of note, critically ill hospitalized patients without COVID-19 had similar reductions in VWF activity-to-antigen ratios as patients with COVID-19. Our data suggest that qualitative changes in VWF in COVID-19 may not be specific to COVID-19. Future studies are warranted to determine the mechanisms responsible for qualitative changes in VWF in COVID-19 and other critical illnesses.• VWF levels were increased in COVID-19 compared to healthy controls.• VWF activity-to-antigen ratios were decreased in COVID-19 compared to healthy controls.• There were no differences in VWF activity-to-antigen ratios between hospitalized patients with or without COVID-19.• These findings are consistent with qualitative changes in VWF in systemic inflammation which are not specific to COVID-19.• Future studies are needed to define possible roles of changes in conformation or multimer length in the qualitative changes in VWF in systemic inflammation.

Cardiac gene activation varies between young and adult cats and in the presence of hypertrophic cardiomyopathy

Little is known about the difference of myocardial gene transcription in young and adult cats and how transcription is further modified in cats with hypertrophic cardiomyopathy (HCM) and with left atrial (LA) thrombus formation. We hypothesized that selected factors for coagulation, endothelial activation, inflammation, and remodelling are modified with age and are activated in the hearts of cats with HCM. Left atrial and ventricular (LV) samples from 12 cats with HCM (seven without (HCMwoAT] and five with LA thrombi [HCMwAT]), and six young (YC) and six adult (AC) control cats without cardiac disease were investigated for relative expression of the following genes using quantitative polymerase chain reaction: von Willebrand factor, a disintegrin and metalloproteinase with a thrombospondin type 1 motif member 13, platelet activating factor, E- and P-selectin, intercellular and vascular adhesion molecules-1, ß2-integrin, vascular endothelial growth factor, interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), heat shock protein-70, and myocyte-specific enhancer factor 2C. Significant differences in gene activation were found between YC and AC, and YC and cats with HCM. Compared to AC, MCP-1 and IL-6 were significantly higher in cats with HCM. The presence of an LA thrombus was associated with higher IL-6 expression. These results illustrate the relevance of age and/or lifestyle on gene expression in the feline heart. The gene transcription pattern found in AC hearts might predispose cats to their characteristic cardiac remodelling processes and thrombus formation if disease occurs. It further supports the involvement of inflammation, but not coagulation and endothelial activation, in HCM.

Multigenomic modifications in human circulating immune cells in response to consumption of polyphenol rich extract of yerba mate (Ilex paraguariensis A. St.-Hil.) are suggestive of cardiometabolic protective effects

Mate is a traditional drink obtained from the leaves of yerba mate and rich in a diversity of plant bioactive compounds including polyphenols, particularly chlorogenic acids. Studies, even though limited, suggest that consumption of mate is associated with health effects, including prevention of cardiometabolic disorders. Molecular mechanisms underlying the potential health properties are still largely unknown, especially in humans. The aim of this study was to investigate nutrigenomic effects of mate consumption and identify regulatory networks potentially mediating cardiometabolic health benefits. Healthy middle-aged men at risk for cardiovascular disease consumed a standardized mate extract or placebo for 4 weeks. Global gene expression, including protein coding and non-coding RNAs profiles were determined using microarrays. Biological function analyses were performed using integrated bioinformatic tools. Comparison of global gene expression profiles showed significant change following mate consumption with 2635 significantly differentially expressed genes, among which 6 are miRNAs and 244 are lncRNAs. Functional analyses showed that these genes are involved in regulation of cell interactions and motility, inflammation or cell signaling. Transcription factors, such as MEF2A, MYB or HNF1A, could have their activity modulated by mate consumption either by direct interaction with polyphenol metabolites or by interactions of metabolites with cell signaling proteins, like p38 or ERK1/2, that could modulate transcription factor activity and regulate expression of genes observed. Correlation analysis suggests that expression profile is inversely associated with gene expression profiles of patients with cardiometabolic disorders. Therefore, mate consumption may exert cardiometabolic protective effects by modulating gene expression towards a protective profile.

The Effect of Sex-Mismatched Red Blood Cell Transfusion on Endothelial Cell Activation in Critically Ill Patients

BACKGROUND

Observational studies suggest that sex-mismatched transfusion is associated with increased mortality. Mechanisms driving mortality are not known but may include endothelial activation. The aim of this study is to investigate the effects of sex-mismatched red blood cell (RBC) transfusions on endothelial cell activation markers in critically ill patients.

STUDY DESIGN AND METHODS

In patients admitted to the intensive care unit who received a single RBC unit, blood samples were drawn before (T0), 1 h after (T1), and 24 h after transfusion (T24) for analysis of soluble syndecan-1, soluble intercellular adhesion molecule-1, soluble thrombomodulin (sTM), von Willebrand factor antigen, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNFα). Changes in the levels of these factors were compared between sex-matched and sex-mismatched groups.

RESULTS

Of 69 included patients, 32 patients were in the sex-matched and 37 patients were in the sex-mismatched group. Compared to baseline, sex-matched transfusion was associated with significant reduction in sTM level (p value = 0.03). Between-group comparison showed that levels of syndecan-1 and sTM were significantly higher in the sex-mismatched group compared to the sex-matched group at T24 (p value = 0.04 and 0.01, respectively). Also, TNFα and IL-6 levels showed a statistically marginal significant increase compared to baseline in the sex-mismatched group at T24 (p value = 0.06 and 0.05, respectively), but not in the sex-matched group.

DISCUSSION

Transfusion of a single sex-mismatched RBC unit was associated with higher syndecan-1 and sTM levels compared to transfusion of sex-matched RBC unit. These findings may suggest that sex-mismatched RBC transfusion is associated with endothelial activation.

Beyond Hemostasis: Platelet Innate Immune Interactions and Thromboinflammation

There is accumulating evidence that platelets play roles beyond their traditional functions in thrombosis and hemostasis, e.g., in inflammatory processes, infection and cancer, and that they interact, stimulate and regulate cells of the innate immune system such as neutrophils, monocytes and macrophages. In this review, we will focus on platelet activation in hemostatic and inflammatory processes, as well as platelet interactions with neutrophils and monocytes/macrophages. We take a closer look at the contributions of major platelet receptors GPIb, α_IIbβ₃, TLT-1, CLEC-2 and Toll-like receptors (TLRs) as well as secretions from platelet granules on platelet-neutrophil aggregate and neutrophil extracellular trap (NET) formation in atherosclerosis, transfusion-related acute lung injury (TRALI) and COVID-19. Further, we will address platelet-monocyte and macrophage interactions during cancer metastasis, infection, sepsis and platelet clearance.

Circulating ADAMTS13 Levels Are Associated with an Increased Occurrence of Obstructive Sleep Apnea

Background and Aims. Obstructive sleep apnea (OSA) is strongly associated with obesity, metabolic diseases, coronary artery disease (CAD), stroke, hypertension, and other disorders. This study assessed the relationship between circulating a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13) levels and the presence of OSA. Materials and Methods. This cross-sectional study included a total of 223 patients. We used a powerful high-throughput multiplexed immunobead-based assay to detect circulating levels of ADAMTS13. The associations between circulating ADAMTS13 levels and OSA were evaluated by multivariate logistic regression analysis. Results. Circulating ADAMTS13 levels were significantly elevated in patients with OSA compared with controls (0.8 vs. 2.7 μg/mL, respectively, $P<0.001$ ). After adjusting for confounding factors, circulating ADAMTS13 levels were significantly independently associated with the presence of OSA ( $\text{odds}\text{ratio}=9.96$ , 95% confidence interval (CI) =4.11–24.13, $P<0.001$ ). Furthermore, circulating ADAMTS13 levels showed discriminatory accuracy in assessing the presence of OSA (area under the curve: 0.87, 95% CI 0.81–0.93, $P<0.001$ ). Conclusion. Circulating ADAMTS13 levels were significantly correlated with the presence of OSA. ADAMTS13 may therefore function as a novel biomarker for monitoring the development and progression of OSA.

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.

Transcriptional landscape of circulating platelets from patients with COVID-19 reveals key subnetworks and regulators underlying SARS-CoV-2 infection: implications for immunothrombosis

Background

Thrombosis and coagulopathy are pervasive pathological features of coronavirus disease 2019 (COVID-19), and thrombotic complications are a sign of severe COVID-19 disease and are associated with multiple organ failure and increased mortality. Platelets are essential cells that regulate hemostasis, thrombus formation and inflammation; however, the mechanism underlying the interaction between platelets and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unclear.

Results

The present study performed RNA sequencing on the RNA isolated from platelets obtained from 10 COVID-19 patients and eight healthy donors, and discovered that SARS-CoV-2 not only significantly altered the coding and non-coding transcriptional landscape, but also altered the function of the platelets, promoted thrombus formation and affected energy metabolism of platelets. Integrative network biology analysis identified four key subnetworks and 16 risk regulators underlying SARS-CoV-2 infection, involved in coronavirus disease-COVID-19, platelet activation and immune response pathways. Furthermore, four risk genes (upstream binding transcription factor, RNA polymerase II, I and III subunit L, Y-box binding protein 1 and yippee like 2) were found to be associated with COVID-19 severity. Finally, a significant alteration in the von Willebrand factor/glycoprotein Ib-IX-V axis was revealed to be strongly associated with platelet aggregation and immunothrombosis.

Conclusions

The transcriptional landscape and the identification of critical subnetworks and risk genes of platelets provided novel insights into the molecular mechanisms of immunothrombosis in COVID-19 progression, which may pave the way for the development of novel therapeutic strategies for preventing COVID-19-associated thrombosis and improving the clinical outcome of COVID-19 patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00750-5.

Effects of Inflammation on Hemostasis in Acutely Ill Patients with Liver Disease

Patients with liver diseases are in a rebalanced state of hemostasis, due to simultaneous decline in pro- and anticoagulant factors. This balance seems to remain even in the sickest patients, but is less stable and might destabilize when patients develop disease complications. Patients with acute decompensation of cirrhosis, acute-on-chronic liver failure, or acute liver failure often develop complications associated with changes in the hemostatic system, such as systemic inflammation. Systemic inflammation causes hemostatic alterations by adhesion and aggregation of platelets, release of von Willebrand factor (VWF), enhanced expression of tissue factor, inhibition of natural anticoagulant pathways, and inhibition of fibrinolysis. Laboratory tests of hemostasis in acutely-ill liver patients may indicate a hypocoagulable state (decreased platelet count, prolongations in prothrombin time and activated partial thromboplastin time, decreased fibrinogen levels) due to decreased synthetic liver capacity or consumption, or a hypercoagulable state (increased VWF levels, hypofibrinolysis in global tests). Whether these changes are clinically relevant and should be corrected with antithrombotic drugs or blood products is incompletely understood. Inflammation and activation of coagulation may cause local ischemia, progression of liver disease, and multiorgan failure. Anti-inflammatory treatment in acutely-ill liver patients may be of potential interest to prevent thrombotic or bleeding complications and halt progression of liver disease.

Circulating miR-3656 induces human umbilical vein endothelial cell injury by targeting eNOS and ADAMTS13: a novel biomarker for hypertension

BACKGROUND

Hypertension, as one of the most common chronic diseases, is a major public health issue. Previous studies have shown that there are miRNAs differentially expressed in hypertensive patients. In addition, hypertension is closely related to endothelial dysfunction, and miRNAs have been identified as important molecular mediators for endothelial function. Therefore, it is necessary to identify specific miRNAs related to hypertension and explore their molecular mechanism in the progression of hypertension.

METHODS

We investigated the association of circulating levels of miR-3656 with hypertension. Furthermore, in-vitro studies were performed to investigate its possible mechanisms for hypertension in that the direct target genes of miR-3656 were confirmed using dual-luciferase reporter assay; moreover, the effects of miR-3656 on proliferation, migration, apoptosis, and microvascular rarefaction of HUVECs were investigated using MTS kit, wound-healing assay, FITC Annexin V apoptosis detection kit, and tube formation assay, correspondingly.

RESULTS

Circulating miR-3656 was upregulated in patients with hypertension. MiR-3656 suppressed the proliferation, migration, and angiogenesis of HUVECs, but promoted the apoptosis of HUVECs. In addition, eNOS and ADAMTS13 were direct target genes of miR-3656, and overexpression of eNOS and ADAMTS13 abolished the effect of miR-3656 on HUVECs.

CONCLUSION

MiR-3656 is a potential biomarker for hypertension. MiR-3656 is involved in endothelial cellular injury implicated in hypertension by targeting eNOS and ADAMTS13.

Epigenetic Modification of the VWF Promotor Drives Platelet Aggregation on the Pulmonary Endothelium in Chronic Thromboembolic Pulmonary Hypertension

RATIONALE

Von Willebrand Factor (VWF) mediates platelet adhesion during thrombosis. While chronic thromboembolic pulmonary hypertension (CTEPH) is associated with increased plasma levels of VWF, the role of this protein in CTEPH has remained enigmatic.

OBJECTIVE

To identify the role of VWF in CTEPH.

METHODS

CTEPH-specific patient plasma and pulmonary endarterectomy material from CTEPH patients were used to study the relationship between inflammation, VWF expression and pulmonary thrombosis. Cell culture findings were validated in human tissue and proteomics and chromatin immunoprecipitation were used to investigate the underlying mechanism of CTEPH.

MEASUREMENTS AND MAIN RESULTS

VWF is increased in plasma and in the pulmonary endothelium of CTEPH patients. In vitro, the increase in VWF gene expression and the higher release of VWF protein upon endothelial activation resulted in elevated platelet adhesion to CTEPH endothelium. Proteomic analysis revealed that Nuclear Factor κB 2 (NFκB2) was significantly increased in CTEPH. We demonstrate reduced histone tri-methylation and increased histone acetylation of the VWF promotor in CTEPH endothelium, facilitating binding of NFκB2 to the VWF promotor and driving VWF transcription. Genetic interference of NFκB2 normalized the high VWF RNA expression levels and reversed the pro-thrombotic phenotype observed in CTEPH-PAEC.

CONCLUSION

Epigenetic regulation of the VWF promotor contributes to the creation of a local environment that favors in situ thrombosis in the pulmonary arteries. It reveals a direct molecular link between inflammatory pathways and platelet adhesion in the pulmonary vascular wall, emphasizing a possible role of in situ thrombosis in the development or progression of CTEPH.

Elucidation of Cellular Contributions to Heparin-Induced Thrombocytopenia Using Omic Approaches

Heparin-induced thrombocytopenia (HIT) is an unpredictable, complex, immune-mediated adverse drug reaction associated with a high mortality. Despite decades of research into HIT, fundamental knowledge gaps persist regarding HIT likely due to the complex and unusual nature of the HIT immune response. Such knowledge gaps include the identity of a HIT immunogen, the intrinsic roles of various cell types and their interactions, and the molecular basis that distinguishes pathogenic and non-pathogenic PF4/heparin antibodies. While a key feature of HIT, thrombocytopenia, implicates platelets as a seminal cell fragment in HIT pathogenesis, strong evidence exists for critical roles of multiple cell types. The rise in omic technologies over the last decade has resulted in a number of agnostic, whole system approaches for biological research that may be especially informative for complex phenotypes. Applying multi-omics techniques to HIT has the potential to bring new insights into HIT pathophysiology and identify biomarkers with clinical utility. In this review, we review the clinical, immunological, and molecular features of HIT with emphasis on key cell types and their roles. We then address the applicability of several omic techniques underutilized in HIT, which have the potential to fill knowledge gaps related to HIT biology.

Role of von Willebrand factor in venous thromboembolic disease

Objective

Evolving evidence of the shared risk factors and pathogenic mechanisms in arterial and venous thrombosis questions of the strict vascular dichotomy of arterial vs venous. The connection between arterial and venous thrombosis has been highlighted by common underlying inflammatory processes, a concept known as thromboinflammatory disease. Using this relationship, we can apply knowledge from arterial disease to better understand and potentially mitigate venous disease. A protein that has been extensively studied in atherothrombotic disease and inflammation is von Willebrand factor (VWF). Because many predisposing and provoking factors of venous thromboembolism (VTE) have been shown to directly modulate VWF levels, it is, perhaps, not surprising that VWF has been highlighted by several recent association studies of patients with VTE.

Methods

In the present narrative review, we investigated more deeply the effects of VWF in venous disease by synthesizing the data from clinical studies of deep vein thrombosis of the limbs, pulmonary embolism, portal and cerebral vein thrombosis, and the complications of thrombosis, including post-thrombotic syndrome, venous insufficiency, and chronic thromboembolic pulmonary hypertension. We have also discussed the findings from preclinical studies to highlight novel VWF biochemistry in thrombosis and therapeutics.

Results

Across the spectrum of venous thromboembolic disease, we consistently observed that elevated VWF levels conferred an increased risk of VTE and long-term venous complications. We have highlighted important findings from VWF molecular research and have proposed mechanisms by which VWF participates in venous disease. Emerging evidence from preclinical studies might reveal novel targets for thromboinflammatory disease, including specific VWF pathophysiology. Furthermore, we have highlighted the utility of measuring VWF to prognosticate and risk stratify for VTE and its complications.

Conclusions

As the prevalence of inflammatory processes, such as aging, obesity, and diabetes increases in our population, it is critical to understand the evolving role of VWF in venous disease to guide clinical decisions and therapeutics.

Tissue dynamics of von Willebrand factor characterized by a novel fluorescent protein-von Willebrand factor chimera

BACKGROUND

Tissue dynamics of von Willebrand factor (VWF) that are vital to its biological function have not been fully characterized.

OBJECTIVE

To develop a new fluorescent protein--VWF chimera (FP-VWF) that has similar hematologic function to wild-type VWF and use it to monitor the tissue dynamics of VWF distribution.

METHODS

Genotyping, platelet counting, tail bleeding time assay, agarose gels, western blot, platelet aggregation, proteolytic analysis, and ELISA were applied in characterizing the function of FP-VWF; fluorescence spectrometer and confocal fluorescence microscope were used to monitor the plasma and tissue distribution of FP-VWF.

RESULTS

The transgenic mice that carry the FP-VWF retain hematologic activity of VWF with plasma levels of FP-VWF reduced by 50% and there are reduced high molecular weight FP-VWF multimers compared to the wild-type mice. The GPIb-binding and ADAMTS-13 (A Disintegrin and Metalloprotease with ThrombSpondin type 1 motif, member 13) proteolytic efficiency of FP-VWF are similar to wild-type VWF. The tissue distribution of FP-VWF was probed directly through its intrinsic fluorescence at normal or stimulated status, which indicated that the medicine-stimulated endogenous FP-VWF seems primarily released from the aorta and cleared in the spleen. Similar results were observed in non-fluorescent mice through a standard immunofluorescence approach. The fluorescence signals of FP-VWF were also similar to the standard dye-based approach in detecting the FeCl3 -induced blood clotting in vivo.

CONCLUSIONS

Together, these results suggest that this novel FP-VWF chimera is valuable in probing the tissue dynamics of VWF in quite a few biological and pharmaceutical applications.

Role of Circulating Microparticles in Type 2 Diabetes Mellitus: Implications for Pathological Clotting

Type 2 diabetes mellitus (T2DM) is a multifactorial chronic metabolic disease characterized by chronic hyperglycemia due to insulin resistance and a deficiency in insulin secretion. The global diabetes pandemic relates primarily to T2DM, which is the most prevalent form of diabetes, accounting for over 90% of all cases. Chronic low-grade inflammation, triggered by numerous risk factors, and the chronic activation of the immune system are prominent features of T2DM. Here we highlight the role of blood cells (platelets, and red and white blood cells) and vascular endothelial cells as drivers of systemic inflammation in T2DM. In addition, we discuss the role of microparticles (MPs) in systemic inflammation and hypercoagulation. Although once seen as inert by-products of cell activation or destruction, MPs are now considered to be a disseminated storage pool of bioactive effectors of thrombosis, inflammation, and vascular function. They have been identified to circulate at elevated levels in the bloodstream of individuals with increased risk of atherothrombosis or cardiovascular disease, two significant hallmark conditions of T2DM. There is also general evidence that MPs activate blood cells, express proinflammatory and coagulant effects, interact directly with cell receptors, and transfer biological material. MPs are considered major players in the pathogenesis of many systemic inflammatory diseases and may be potentially useful biomarkers of disease activity and may not only be of prognostic value but may act as novel therapeutic targets.

von Willebrand Factor Gene Polymorphism in Preeclampsia Pregnant at Medan, Indonesia

BACKGROUND: von Willebrand Factor (vWF) is a large glycoprotein mediating hemostasis and thrombosis. The roles of vWF are platelets adhesion to sites of vascular damage and stabilization of coagulation factor VIII. AIM: This study aimed to analyze the polymorphism of the vWF gene on preeclampsia (PE) in pregnancy in Medan, Indonesia. MATERIALS AND METHODS: DNA was amplified using the polymerase chain reaction and was electrophoresed in agarose 2%. Electrophoresis results were detected using Gel Doc 1000 (Biorad, USA). The sequencing method was used to identify polymorphism from vWF gene. RESULTS: From 50 samples of PE patients, the g.93308C>T vWF gene polymorphism was found with the percentage of TT, CT, and CC genotypes as 50%, 42%, and 8%, respectively. CONCLUSION: The c.93308C>T vWF gene polymorphism was found in the genotype percentage of homozygous TT, and heterozygote CT was greater than wild-type CC.

High levels of Von Willebrand factor markers in COVID-19: a systematic review and meta-analysis

The SARS-CoV-2 virus has spread to all corners of the world. Thrombosis is the cause of organ failure and subsequent death in COVID-19. The pathophysiology of thrombosis in COVID-19 needs to be further explored to shed light on its downside. For this reason, this meta-analysis of Von Willebrand Factor profile (VWF: Ag, VWF: activity, VWF: RCo), ADAMTS-13, and factor VIII levels in COVID-19 was performed. To obtain data on the status of the aforementioned hemostatic factors, a systematic literature review and meta-analysis were performed on COVID-19. After reviewing the evaluation of 348 papers, 28 papers included in the meta-analysis, which was performed using STATA. The analysis showed an increase in VWF: Ag levels in COVID‐19 patients. VWF: Ac was higher in all COVID-19 patients, while it was lower in the COVID‐19 ICU patients. The pooled mean of VWF: RCO in all patients with COVID-19 was 307.94%. In subgroup analysis, VWF: RCO was significantly higher in ICU patients than in all COVID-19 patients. The pooled mean of ADAMTS-13 activity was 62.47%, and 58.42% in ICU patients. The pooled mean of factor VIII level was 275.8%, which was significantly higher in ICU patients with COVID-19 than all patients with COVID-19. Levels of VWF: Ag, VWF: activity, VWF: ristocetin, and factor VIII are increased in patients with COVID-19. The elevated levels in ICU patients with COVID-19 suggest that these markers may have prognostic value in determining the severity of COVID-19. New therapeutic programs can be developed as a result.

Intracellular receptor EPAC regulates von Willebrand factor secretion from endothelial cells in a PI3K-/eNOS-dependent manner during inflammation

Coagulopathy is associated with both inflammation and infection, including infections with novel severe acute respiratory syndrome coronavirus-2, the causative agent Coagulopathy is associated with both inflammation and infection, including infection with novel severe acute respiratory syndrome coronavirus-2, the causative agent of COVID-19. Clot formation is promoted via cAMP-mediated secretion of von Willebrand factor (vWF), which fine-tunes the process of hemostasis. The exchange protein directly activated by cAMP (EPAC) is a ubiquitously expressed intracellular cAMP receptor that plays a regulatory role in suppressing inflammation. To assess whether EPAC could regulate vWF release during inflammation, we utilized our EPAC1-null mouse model and revealed increased secretion of vWF in endotoxemic mice in the absence of the EPAC1 gene. Pharmacological inhibition of EPAC1 in vitro mimicked the EPAC1-/- phenotype. In addition, EPAC1 regulated tumor necrosis factor-α-triggered vWF secretion from human umbilical vein endothelial cells in a manner dependent upon inflammatory effector molecules PI3K and endothelial nitric oxide synthase. Furthermore, EPAC1 activation reduced inflammation-triggered vWF release, both in vivo and in vitro. Our data delineate a novel regulatory role for EPAC1 in vWF secretion and shed light on the potential development of new strategies to control thrombosis during inflammation.

Complex Interaction of Platelets, von Willebrand Factor and Leukocytes, in Whole Blood at High Shear Rates Is Mediated by Platelet GPIIb/IIIa Receptor

We studied the contribution of von Willebrand factor (vWF) into blood cell adhesion to collagen-coated surfaces in whole blood of healthy volunteers. Adhesion of blood cells to collagen I was measured at shear rate of 2300 sec^-1. The interaction of platelet GPIIb/IIIa receptor with vWF was blocked with monoclonal anti-GPIIb/IIIa antibodies. The degree of cell adhesion was quantified by measuring the intensity of scattered light after 15-min perfusion: in samples with blocked GPIIb/IIIa it decreased to 0.39±0.13 V vs 0.06±0.03 V in control samples (p=0.002). Under a fluorescence microscope, intensively stained structures consisting of vWF, platelets, and leukocytes attached to the collagen surface were observed. After blockade of GPIIb/IIIa, these structures were absent. Leukocyte recruitment at high shear rates is a time-dependent process sensitive to complex interaction of vWF, leukocytes, and platelets, in which the platelet GPIIb/IIIa receptor is essential.

The Role and Molecular Mechanism of P2Y12 Receptors in the Pathogenesis of Atherosclerotic Cardiovascular Diseases

The P2Y receptor family is a class of G protein-coupled receptors activated primarily by adenosine triphosphate (ATP), adenosine diphosphate (ADP), uridine triphosphate (UTP) and uridine diphosphate (UDP). The P2Y12 receptor is expressed on platelets which mediates platelet aggregation and morphological changes. At the same time, during the process of vascular remodeling and atherosclerosis, ADP can also promote the migration and proliferation of vascular smooth muscle and endothelial cells through P2Y12 receptor activating. Furthermore, P2Y12 is involved in many signal transductions processes, such as intimal hyperplasia, monocyte infiltration and so on, which play an important role in immune inflammation and brain injury. In order to solve the diseases induced by P2Y12 receptor, inhibitors such as ticagrelor, clopidogrel were widely used for cardiovascular diseases. However, there were some problems, such as limited antithrombotic effect, remain unsolved. This article summarizes the role and molecular mechanism of P2Y12 receptors in the pathogenesis of cardiovascular-related diseases, providing in-depth expounding on the molecular mechanism of P2Y12 receptor inhibitors and contributing to the treatment of diseases based on P2Y12 receptors.

Anti-inflammatory diet and venous thromboembolism: Two prospective cohort studies

BACKGROUND AND AIMS

Inflammation has been revealed to facilitate thrombogenesis and to increase the risk of venous thromboembolism (VTE). However, limited data are available on the association between the anti-inflammatory diet and incident VTE. We conducted a cohort analysis to examine this association and to further examine whether this association is modified by smoking status, a trigger of systemic inflammation.

METHODS AND RESULTS

We used data from two cohorts including 81,507 middle-aged and older Swedish adults without previous VTE at baseline. An empirically validated anti-inflammatory diet index (AIDI), based on 12 foods with anti-inflammatory potential and 5 foods with pro-inflammatory potential, was employed to estimate the anti-inflammatory potential of diet. Hazard ratios (HRs), with corresponding 95% confidence intervals (CIs), of VTE were estimated by Cox proportional hazards regression models. During a mean follow-up of 17.8-years, 5241 VTE cases were diagnosed. Compared with individuals in the lowest quartile of the AIDI (score ≤4), those in the highest quartile (score ≥8) had a 9% (95% CI, 0-17%) lower risk of VTE. The inverse association was observed in current and past smokers (HR between the two extreme quartiles, 0.80, 95% CI, 0.70-0.91) but not in never smokers (HR, 1.03, 95% CI, 0.91-1.17). French fries (HR per serving, 1.33, 95% CI, 1.06, 1.67) but no other foods included in AIDI was associated with VTE.

CONCLUSION

The study suggests that a consumption of foods with high anti-inflammatory potential may play a role in the prevention of VTE in smokers.

Involvement of von Willebrand factor and botrocetin in the thrombocytopenia induced by Bothrops jararaca snake venom

Patients bitten by snakes consistently manifest a bleeding tendency, in which thrombocytopenia, consumption coagulopathy, mucous bleeding, and, more rarely, thrombotic microangiopathy, are observed. Von Willebrand factor (VWF) is required for primary hemostasis, and some venom proteins, such as botrocetin (a C-type lectin-like protein) and snake venom metalloproteinases (SVMP), disturb the normal interaction between platelets and VWF, possibly contributing to snakebite-induced bleedings. To understand the relationship among plasma VWF, platelets, botrocetin and SVMP from Bothrops jararaca snake venom (BjV) in the development of thrombocytopenia, we used (a) Wistar rats injected s.c. with BjV preincubated with anti-botrocetin antibodies (ABA) and/or Na2-EDTA (a SVMP inhibitor), and (b) VWF knockout mice (Vwf-/-) injected with BjV. Under all conditions, BjV induced a rapid and intense thrombocytopenia. In rats, BjV alone reduced the levels of VWF:Ag, VWF:CB, high molecular weight multimers of VWF, ADAMTS13 activity, and factor VIII. Moreover, VWF:Ag levels in rats that received BjV preincubated with Na2-EDTA and/or ABA tended to recover faster. In mice, BjV caused thrombocytopenia in both Vwf-/- and C57BL/6 (background control) strains, and VWF:Ag levels tended to decrease in C57BL/6, demonstrating that thrombocytopenia was independent of the presence of plasma VWF. These findings showed that botrocetin present in BjV failed to affect the extent or the time course of thrombocytopenia induced by envenomation, but it contributed to decrease the levels and function of plasma VWF. Thus, VWF alterations during B. jararaca envenomation are an ancillary event, and not the main mechanism leading to decreased platelet counts.

The SARS-CoV-2/Receptor Axis in Heart and Blood Vessels: A Crisp Update on COVID-19 Disease with Cardiovascular Complications

The SARS-CoV-2 virus causing COVID-19 disease has emerged expeditiously in the world and has been declared pandemic since March 2020, by World Health Organization (WHO). The destructive effects of SARS-CoV-2 infection are increased among the patients with pre-existing chronic conditions and, in particular, this review focuses on patients with underlying cardiovascular complications. The expression pattern and potential functions of SARS-CoV-2 binding receptors and the attributes of SARS-CoV-2 virus tropism in a physio-pathological state of heart and blood vessel are precisely described. Of note, the atheroprotective role of ACE2 receptors is reviewed. A detailed description of the possible detrimental role of SARS-CoV-2 infection in terms of vascular leakage, including endothelial glycocalyx dysfunction and bradykinin 1 receptor stimulation is concisely stated. Furthermore, the potential molecular mechanisms underlying SARS-CoV-2 induced clot formation in association with host defense components, including activation of FXIIa, complements and platelets, endothelial dysfunction, immune cell responses with cytokine-mediated action are well elaborated. Moreover, a brief clinical update on patient with COVID-19 disease with underlying cardiovascular complications and those who had new onset of cardiovascular complications post-COVID-19 disease was also discussed. Taken together, this review provides an overview of the mechanistic aspects of SARS-CoV-2 induced devastating effects, in vital organs such as the heart and vessels.

Thrombosis associated with mycoplasma pneumoniae infection (Review)

Mycoplasma pneumoniae is a common pathogen causing respiratory infections in children and adults. In addition to respiratory diseases, Mycoplasma pneumoniae is also involved in numerous extrapulmonary diseases. Thrombosis is an extrapulmonary manifestation associated with Mycoplasma pneumoniae infection. In recent years, an increasing number of case reports have been published identifying thrombosis secondary to Mycoplasma pneumoniae infection. In the present study, the available relevant literature in English available on PubMed, Medline and Web of Science was consulted. The results of the present study demonstrated that in patients with thrombosis caused by Mycoplasma pneumoniae infection, some of the factors causing thrombosis are transient and some are due to hereditary thrombophilia. Following timely treatment, the majority of patients recovered completely but some patients had a poor prognosis. The present review focuses on the pathogenesis, clinical features, treatment and prognosis of this crucial issue, which contributes toward the understanding of the disease.

Illustrated State-of-the-Art Capsules of the ISTH 2020 Congress

This year's Congress of the International Society of Thrombosis and Haemostasis (ISTH) was hosted virtually from Philadelphia July 17-21, 2021. The conference, now held annually, highlighted cutting-edge advances in basic, population and clinical sciences of relevance to the Society. Despite being held virtually, the 2021 congress was of the same scope and quality as an annual meeting held in person. An added feature of the program is that talks streamed at the designated times will then be available on-line for asynchronous viewing. The program included 77 State of the Art (SOA) talks, thematically grouped in 28 sessions, given by internationally recognized leaders in the field. The SOA speakers were invited to prepare brief illustrated reviews of their talks that were peer reviewed and are included in this article. The topics, across the main scientific themes of the congress, include Arterial Thromboembolism, Coagulation and Natural Anticoagulants, COVID-19 and Coagulation, Diagnostics and Omics, Fibrinogen, Fibrinolysis and Proteolysis, Hemophilia and Rare Bleeding Disorders, Hemostasis in Cancer, Inflammation and Immunity, Pediatrics, Platelet Disorders, von Willebrand Disease and Thrombotic Angiopathies, Platelets and Megakaryocytes, Vascular Biology, Venous Thromboembolism and Women's Health. These illustrated capsules highlight the major scientific advances with potential to impact clinical practice. Readers are invited to take advantage of the excellent educational resource provided by these illustrated capsules. They are also encouraged to use the image in social media to draw attention to the high quality and impact of the science presented at the congress.

Von Willebrand Factor in Health and Disease

Abstract—

Von Willebrand factor (vWF), the key component of hemostasis, is synthesized in endothelial cells and megakaryocytes and released into the blood as high molecular weight multimeric glycoproteins weighing up to 20 million Daltons. Blood plasma metalloprotease ADAMTS13 cleaves ultra-large vWF multimers to smaller multimeric and oligomeric molecules. The vWF molecules attach to the sites of damage at the surface of arterioles and capillaries and unfold under conditions of shear stress. On the unfolded vWF molecule, the regions interacting with receptors on the platelet membrane are exposed. After binding to the vWF filaments, platelets are activated; platelets circulating in the vessels are additionally attached to them, leading to thrombus formation, blocking of microvessels, and cessation of bleeding. This review describes the history of the discovery of vWF, presents data on the mechanisms of vWF secretion and its structure, and characterizes the processes of vWF metabolism in the body under normal and pathological conditions.

[Correlation of serum ADAMTS13 and TSP1 levels with myocardial injury and prognosis in patients with acute coronary syndrome]

OBJECTIVE

To investigate serum levels of von Willebrand factor lytic protease (ADAMTS13) and thrombospondin-1 (TSP1) in patients with different types of acute coronary syndrome (ACS) and their correlation with the patients' clinical prognosis.

OBJECTIVE

According to their disease history, results of angiography and clinical biochemical tests, a total of 405 patients undergoing coronary angiography, were divided into unstable angina (UAP) group (n=215), acute myocardial infarction (AMI) group (n=96), and angiographically normal group (n=94). Serum ADAMTS13 and TSP1 levels were detected in all the patients, who were followed up for 15 months to evaluate the occurrence of long-term major cardiac adverse events (MACE).

OBJECTIVE

Serum ADAMTS13 level was significantly lower and TSP1 level was significantly higher in AMI group and UAP group than in the normal group (P < 0.001). Serum ADAMTS13 and TSP1 levels were negative correlated in ACS patients (R=-0.577, P < 0.001). The patients experiencing MACE had significantly different serum TSP1 level from those without MACE (P < 0.05). Cox proportion regression model analysis showed that TSP1 was a risk factor affecting the occurrence of MACE in ACS patients; Kaplan-Meier survival analysis showed that the patients with high levels of TSP1 had a higher incidence of longterm MACE than those with low TSP1 levels.

OBJECTIVE

A lowered serum ADAMTS13 level and an elevated TSP1 level can support the diagnosis of ACS. An elevated TSP1 level may serve as an indicator for predicting the risk of MACE in patients with ACS.

The Impact of Thromboprophylaxis on the Survival of Patients with Advanced Pancreatic Cancer. The Pancreatic Cancer and Tinzaparin (PaCT) Study

Simple Summary

Pancreatic cancer (PaC) induces a prothrombotic and hypercoagulable state. Thrombosis occurs in 20% of PaC patients and is associated with worse prognosis and reduced progression-free survival (PFS). The aim of this retrospective observational study (PaCT) was to investigate the effect of thromboprophylaxis with an intermediate dose of tinzaparin on the PFS of patients treated with nab-paclitaxel and gemcitabine. Data obtained from 110 patients with active PaC administered prophylaxis with tinzaparin during the study resulted in median PFS of 7.9 months; data for the PFS of patients without simultaneous anticoagulation were obtained bibliographically from 14 studies, and after applying meta-analysis was 5.6 months. Patients receiving anticoagulation with tinzaparin had 39.5% higher PFS than patients without such thromboprophylaxis (p < 0.05). During follow-up, three (2.7%) thrombotic events and two (1.9%) clinically relevant non-major bleeding events occurred. Concluding, PFS in advanced PaC patients undergoing chemotherapy was positively impacted by thromboprophylaxis with intermediate dose tinzaparin.

Abstract

Pancreatic cancer (PaC) induces a prothrombotic and hypercoagulable state. The aim of this study was to investigate the effect of tinzaparin in combination with chemotherapy. The PaCT (pancreatic cancer and tinzaparin) study was a retrospective observational study that collected data regarding progression free survival (PFS) in advanced or metastatic PaC patients who received thromboprophylaxis with tinzaparin during chemotherapy with nab-paclitaxel (N) and gemcitabine (G). The primary end point was to compare, from already published data, the PFS of patients receiving thromboprophylaxis with tinzaparin with the PFS of patients receiving chemotherapy with N–G but no thromboprophylaxis. Secondary end points were efficacy and safety of anticoagulation. In total, 110 PaC patients, 93% with advanced or metastatic disease, treated with N–G and tinzaparin (10,291 ± 1176 Anti-Xa IU, OD, median duration 8.7, IQR: 5.6–11.9 months) were enrolled. Of these, 52% were males and; the median age was 68 (40–86 years). The tumor was located to in the pancreatic head at in 45% of the patients. The median PFS was 7.9 months (IQR: 5.0–11.8 months). Out of 14 similar studies (involving 2994 patients) identified via systematic search, it was determined that the weighted PFS of patients receiving N–G but no anticoagulation was 5.6 months. Therefore, patients receiving tinzaparin had 39.54% higher PFS than patients without thromboprophylaxis (p < 0.05). During the follow-up period of 18.3 ± 11.7 months, three (2.7%) thrombotic events were recorded while two clinically relevant non-major bleeding events occurred (1.9%). In conclusion, PFS in advanced PaC patients undergoing chemotherapy is positively impacted by anticoagulation. Thromboprophylaxis with tinzaparin in treatment dose is efficient and safe.

Role of Von Willebrand Factor after Injury: It May Do More Than We Think

ABSTRACT

Acute traumatic coagulopathy is a complex phenomenon following injury and a main contributor to hemorrhage. It remains a leading cause of preventable death in trauma patients. This phenomenon is initiated by systemic injury to the vascular endothelium that is exacerbated by hypoperfusion, acidosis, and hypothermia and leads to systemic activation of the coagulation cascades and resultant coagulopathy. Many previous studies have focused on endotheliopathy with targeted markers such as syndecan-1, soluble thrombomodulin, and plasma adrenaline as potential culprits for initiation and propagation of this state. However, in more recent studies, hyperadhesive von Willebrand factor (VWF), which is released following endothelial injury, and its cleaving metalloprotease ADAMTS13 have emerged as significant targets of the downstream effect of endothelial breakdown and coagulation dysregulation. Elucidation of the mechanism by which the dysregulated VWF-ADAMTS13 axis leads to endothelial dysfunction and coagulopathy after trauma can help identify new targets for therapy and sites for intervention. Much of what is known mechanistically regarding VWF stems from work done in traumatic brain injury. Following localized brain injury, brain-derived extracellular vesicles are released into circulation where they induce a hypercoagulable state that rapidly turns into consumptive coagulopathy. VWF released from injured endothelial cells binds to these extracellular vesicles to enhance their activity in promoting coagulopathy and increasing endothelial permeability. However, there are numerous gaps in our knowledge of VWF following injury, providing a platform for further investigation.

Acrolein Induces Systemic Coagulopathy via Autophagy-dependent Secretion of von Willebrand Factor in Mice after Traumatic Brain Injury

Traumatic brain injury (TBI)-induced coagulopathy has increasingly been recognized as a significant risk factor for poor outcomes, but the pathogenesis remains poorly understood. In this study, we aimed to investigate the causal role of acrolein, a typical lipid peroxidation product, in TBI-induced coagulopathy, and further explore the underlying molecular mechanisms. We found that the level of plasma acrolein in TBI patients suffering from coagulopathy was higher than that in those without coagulopathy. Using a controlled cortical impact mouse model, we demonstrated that the acrolein scavenger phenelzine prevented TBI-induced coagulopathy and recombinant ADAMTS-13 prevented acrolein-induced coagulopathy by cleaving von Willebrand factor (VWF). Our results showed that acrolein may contribute to an early hypercoagulable state after TBI by regulating VWF secretion. mRNA sequencing (mRNA-seq) and transcriptome analysis indicated that acrolein over-activated autophagy, and subsequent experiments revealed that acrolein activated autophagy partly by regulating the Akt/mTOR pathway. In addition, we demonstrated that acrolein was produced in the perilesional cortex, affected endothelial cell integrity, and disrupted the blood-brain barrier. In conclusion, in this study we uncovered a novel pro-coagulant effect of acrolein that may contribute to TBI-induced coagulopathy and vascular leakage, providing an alternative therapeutic target.

Recognizing and managing hereditary and acquired thrombotic thrombocytopenic purpura in infants and children

We describe how infants and children with hereditary and acquired autoimmune thrombotic thrombocytopenic purpura (TTP) initially present and how they can be promptly diagnosed and effectively managed. These are uncommon disorders that are commonly misdiagnosed and can be rapidly fatal. TTP is caused by a severe deficiency of the plasma protease, A disintegrin and Metalloprotease with a ThromboSpondin type 1 motif, member 13 (ADAMTS13). Measurement of ADAMTS13 activity is becoming easily accessible. A common presentation of hereditary TTP is neonatal severe hemolysis and hyperbilirubinemia. However, the median age of diagnosis is not until 5.5 years. Plasma is effective treatment for exacerbations and for prophylaxis. Plasma may be replaced by recombinant ADAMTS13 when it becomes available. Acquired TTP is more frequent in older children, in whom it is more common in girls and is commonly associated with systemic lupus erythematosus. For acquired TTP, plasma exchange and immunosuppression are the current treatment for acute episodes; caplacizumab is now commonly used in adults and may replace plasma exchange.

Von Willebrand Factor, Factor VIII, and Other Acute Phase Reactants as Biomarkers of Inflammation and Endothelial Dysfunction in Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGvHD) is an immune mediated late complication of allogeneic hematopoietic stem cell transplantation (alloHSCT). Discovery of adequate biomarkers could identify high-risk patients and provide an effective pre-emptive intervention or early modification of therapeutic strategy, thus reducing prevalence and severity of the disease among long-term survivors of alloHSCT. Inflammation, endothelial injury, and endothelial dysfunction are involved in cGvHD development. Altered levels of acute phase reactants have shown a strong correlation with the activity of several immune mediated disorders and are routinely used in clinical practice. Since elevated von Willebrand factor (VWF) and factor VIII (FVIII) levels have been described as acute phase reactants that may indicate endothelial dysfunction and inflammation in different settings, including chronic autoimmune diseases, they could serve as potential candidate biomarkers of cGvHD. In this review we focused on reported data regarding VWF and FVIII as well as other markers of inflammation and endothelial dysfunction, evaluating their potential role in cGvHD.

Role of von Willebrand Factor in COVID-19 Associated Coagulopathy

Background

COVID-19, the disease caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) can present with symptoms ranging from none to severe. Thrombotic events occur in a significant number of patients with COVID-19, especially in critically ill patients. This apparent novel form of coagulopathy is termed COVID-19 associated coagulopathy and endothelial derived von Willebrand factor (vWF) may play an important role in its pathogenesis.

Content

vWF is a multimeric glycoprotein molecule that is involved in inflammation, primary and secondary hemostasis. Studies have shown that patients with COVID-19 have significantly elevated levels of vWF antigen and activity, likely contributing to an increased risk of thrombosis seen in CAC. The high levels of both vWF antigen and activity have been clinically correlated with worse outcomes. Furthermore, the severity of a COVID-19 infection appears to reduce molecules that regulate vWF level and activity such as ADAMT-13 and high density lipoproteins (HDL). Finally, studies have suggested that patients with blood group O (a blood group with lower than baseline levels of vWF) have a lower risk of infection and disease severity compared to other blood groups; however, more studies are needed to elucidate the role of vWF

Summary

CAC is a significant contributor to morbidity and mortality. Endothelial dysfunction with the release of pro-thrombotic factors, such as vWF, needs further examination as a possible important component in the pathogenesis CAC.

Immunohistological Evaluation of Von Willebrand Factor in the Left Atrial Endocardium and Atrial Thrombi from Cats with Cardiomyopathy

Aortic thromboembolism (ATE) occurs in cats with cardiomyopathy and often results in euthanasia due to poor prognosis. However, the underlying predisposing mechanisms leading to left atrial (LA) thrombus formation are not fully characterised. von Willebrand Factor (vWF) is a marker of endothelium and shows increased expression following endothelial injury. In people with poor LA function and LA remodelling, vWF has been implicated in the development of LA thrombosis. In this study we have shown (1) the expression of endocardial vWF protein detected using immunohistofluorescence was elevated in cats with cardiomyopathy, LA enlargement (LAE) and clinical signs compared to cats with subclinical cardiomyopathy and control cats; (2) vWF was present at the periphery of microthrombi and macrothrombi within the LA where they come into contact with the LA endocardium and (3) vWF was integral to the structure of the macrothrombi retrieved from the atria. These results provide evidence for damage of the endocardial endothelium in the remodelled LA and support a role for endocardial vWF as a pro-thrombotic substrate potentially contributing to the development of ATE in cats with underlying cardiomyopathy and LAE. Results from this naturally occurring feline model may inform research into human thrombogenesis.

Immunohistological Evaluation of Von Willebrand Factor in the Left Atrial Endocardium and Atrial Thrombi from Cats with Cardiomyopathy

Simple Summary

Disease of the heart muscle (cardiomyopathy) is very common in the domestic cat and may result in several severe outcomes. These include formation of a thrombus in the left atrium which migrates to the hindlimb cutting off the blood supply, a condition called aortic thromboembolism. Affected cats present with hindlimb paralysis and extreme pain, often requiring euthanasia on humane grounds. Several factors are known to predispose to thrombus formation, including damage to the inner cellular lining of the atrium which exposes proteins that initiates thrombosis. We studied the expression of one such protein called von Willebrand Factor in the left atrium of cats with and without cardiomyopathies and at different stages of disease severity. We found that expression increased in cats with advance disease. Obtaining a greater understanding of the role this protein has in thrombus formation may allow development of novel antithrombotic agents to help prevent this devastating consequence of feline cardiomyopathy.

Abstract

Aortic thromboembolism (ATE) occurs in cats with cardiomyopathy and often results in euthanasia due to poor prognosis. However, the underlying predisposing mechanisms leading to left atrial (LA) thrombus formation are not fully characterised. von Willebrand Factor (vWF) is a marker of endothelium and shows increased expression following endothelial injury. In people with poor LA function and LA remodelling, vWF has been implicated in the development of LA thrombosis. In this study we have shown (1) the expression of endocardial vWF protein detected using immunohistofluorescence was elevated in cats with cardiomyopathy, LA enlargement (LAE) and clinical signs compared to cats with subclinical cardiomyopathy and control cats; (2) vWF was present at the periphery of microthrombi and macrothrombi within the LA where they come into contact with the LA endocardium and (3) vWF was integral to the structure of the macrothrombi retrieved from the atria. These results provide evidence for damage of the endocardial endothelium in the remodelled LA and support a role for endocardial vWF as a pro-thrombotic substrate potentially contributing to the development of ATE in cats with underlying cardiomyopathy and LAE. Results from this naturally occurring feline model may inform research into human thrombogenesis.

VWF, Platelets and the Antiphospholipid Syndrome

The antiphospholipid syndrome (APS) is characterized by thrombosis and/or pregnancy morbidity with the persistent presence of antiphospholipid antibodies (aPLs). Laboratory criteria for the classification of APS include the detection of lupus anticoagulant (LAC), anti-cardiolipin (aCL) antibodies and anti-β2glycoprotein I (aβ2GPI) antibodies. Clinical criteria for the classification of thrombotic APS include venous and arterial thrombosis, along with microvascular thrombosis. Several aPLs, including LAC, aβ2GPI and anti-phosphatidylserine/prothrombin antibodies (aPS/PT) have been associated with arterial thrombosis. The Von Willebrand Factor (VWF) plays an important role in arterial thrombosis by mediating platelet adhesion and aggregation. Studies have shown that aPLs antibodies present in APS patients are able to increase the risk of arterial thrombosis by upregulating the plasma levels of active VWF and by promoting platelet activation. Inflammatory reactions induced by APS may also provide a suitable condition for arterial thrombosis, mostly ischemic stroke and myocardial infarction. The presence of other cardiovascular risk factors can enhance the effect of aPLs and increase the risk for thrombosis even more. These factors should therefore be taken into account when investigating APS-related arterial thrombosis. Nevertheless, the exact mechanism by which aPLs can cause thrombosis remains to be elucidated.

Von Willebrand Factor Multimers and the Relaxation Response: A One-Year Study

BACKGROUND AND AIM

Mental stress represents a pivotal factor in cardiovascular diseases. The mechanism by which stress produces its deleterious ischemic effects is still under study but some of the most explored pathways are inflammation, endothelial function and balancing of the thrombotic state. In this scenario, von Willebrand factor (vWF) is a plasma glycoprotein best known for its crucial hemostatic role, also acting as key regulatory element of inflammation, being released by the activated vascular endothelium. Antistress techniques seem to be able to slow down inflammation. As we have recently verified how the practice of the Relaxation Response (RR), which counteracts psychological stress, causes favorable changes in some inflammatory genes' expressions, neurotransmitters, hormones, cytokines and inflammatory circulating microRNAs with coronary endothelial function improvement, we aimed to verify a possible change even in serum levels of vWF. Experimental procedure: We measured vWF multimers and the total protein carbonyl contents in the sera of 90 patients with ischemic heart disease (and 30 healthy controls) immediately before and after an RR session, three times (baseline, 6 months, 12 months), during a one-year follow-up study.

RESULTS

According to our data, large vWF multimers decrease during the RR, as does the plasma total carbonyl content.

CONCLUSION

vWF levels seem to vary rapidly between anti-inflammatory and antithrombotic behaviors dependent on psychological activity, leading to relaxation and also possibly changes in its quaternary structure.

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.

Predictors Associated with Outcomes of Epidural Blood Patch in Patients with Spontaneous Intracranial Hypotension

An autologous epidural blood patch (EBP) is a mainstay of treatment in patients with spontaneous intracranial hypotension (SIH). EBP, however, is less effective for SIH than post-dural puncture headaches. Therefore, patients with SIH frequently require an additional EBP. The aim of this study was to identify factors associated with poor response to EBP. This single-center retrospective observational study used the institutional registry records of 321 patients who underwent EBP between September 2001 and March 2016. Patients were divided into two groups, a poor responder group, consisting of patients who underwent EBP at least three times or more, and a good responder group of patients who experienced sufficient symptom relief after two or fewer EBP. The demographic characteristics, clinical features, radiologic findings, procedural data, and laboratory data were analyzed. Univariate analysis showed that the neutrophil-to-lymphocyte ratio (NLR; p = 0.004) and platelet-to-lymphocyte ratio (p = 0.015) were significantly lower in poor than in good responders. Multivariate analysis found that NLR was the only independent factor associated with a poor response (odds ratio = 0.720; p = 0.008). These findings indicate that a low NLR was associated with three or more EBP administrations for the sufficient improvement of symptoms in patients with SIH.