Von Willebrand factor regulation in patients with acute and chronic cerebrovascular disease: a pilot, case-control study

Von Willebrand Factor Antigen Levels Predict Poor Outcomes in Patients With Stroke and Cancer: Findings From the Multicenter, Prospective, Observational SCAN Study

BACKGROUND

Patients with acute ischemic stroke and active cancer have more severe neurological symptoms, elevated risks of stroke recurrence, and death compared with the general population. We examined whether von Willebrand factor (vWF) antigen levels at stroke onset were associated with the poor outcomes of patients with stroke and cancer.

METHODS AND RESULTS

Using data from 90 patients with acute ischemic stroke and active cancer who were registered in the SCAN (Ischemic Stroke in Patients With Cancer and Neoplasia) study, a prospective multicenter, observational study in Japan, we divided patients into 2 groups according to their median vWF antigen levels (high, n=46; or low, n=44). The high-vWF group had a significantly higher initial National Institutes of Health Stroke Scale score (median, 7 [interquartile range, 3-11.25] versus 3 [interquartile range, 1-8.5]; P<0.05) and a significantly higher incidence of cryptogenic stroke (32 [70%] versus 16 [36%]; P<0.01) and venous thromboembolism (7 [15%] versus 0 [0%]; P<0.01), as well as multiple lesions (28 [62%] versus 12 [27%]; P<0.001), than the low-vWF group. We observed no significant difference in the rate of stroke recurrence within 1 year between the groups. However, increased vWF levels were an independent predictor of death within 1 year of stroke onset, after adjusting for potential confounders (odds ratio, 6.77 [95% CI, 1.49-30.78]; P<0.05).

CONCLUSIONS

Elevated vWF antigen levels were associated with adverse outcomes in patients with cancer-associated stroke and may represent a useful biomarker to guide future therapeutic interventions.

Coagulation biomarkers for ischemic stroke

A State of the Art lecture titled "coagulation biomarkers for ischemic stroke" was presented at the International Society on Thrombosis and Haemostasis (ISTH) Congress in 2022. Ischemic stroke (IS) is a common disease with major morbidity and mortality. It is a challenge to determine which patients are at risk for IS or have poor clinical outcome after IS. An imbalance of coagulation markers may contribute to the progression and prognosis of IS. Therefore, we now discuss studies on the association of selected coagulation biomarkers from the hemostasis, inflammation, and immunothrombosis systems with the risk of IS, stroke severity at the acute phase, and clinical outcome after treatment. We report on coagulation biomarker-induced risk of IS, stroke severity, and outcomes following IS derived from prospective population studies, case-control studies, and acute-phase IS studies. We found indications that many coagulation and inflammation biomarkers are associated with IS, but it is early to conclude that any of these biomarkers can be applied in a therapeutic setting to predict patients at risk of IS, stroke severity at the acute phase, and clinical outcome after treatment. The strongest evidence for a role in IS was found for beta-thromboglobulin, von Willebrand factor, factor VIII, fibrinogen, thrombin-activatable fibrinolysis inhibitor, D-dimer, and neutrophil extracellular traps, and therefore, they are promising candidates. Further research and validation in large-size populations using well-defined study designs are warranted. Finally, we provide a selection of recent data relevant to this subject that was presented at the 2022 ISTH Congress.

Circulating endothelial microvesicles and their carried miR-125a-5p: potential biomarkers for ischaemic stroke

Background

Endothelial microvesicles (EMVs) are closely associated with the status of endothelial cells (ECs). Our earlier study has shown that EMVs could exert protective roles in ECs by transferring their carried miR-125a-5p. However, whether circulating EMVs and their carried miR-125a-5p can be used as biomarkers in ischaemic stroke (IS) are remain unknown.

Methods

We recruited 72 subjects with IS, 60 subjects with high stroke risk and 56 age-matched controls. The circulating EMVs and their carried miR-125a-5p (EMV-miR-125a-5p) levels were detected. We used microRNA (miR) array to study expression changes of miRs in plasma EMVs samples of three IS patients and three matched healthy controls. Transient middle cerebral artery occlusion (tMCAO) was used to establish IS mouse model.

Results

EMVs level was obviously elevated in IS patients, with the highest level in acute stage, and was positively related to carotid plaque, carotid intima–media thickness (IMT), National Institutes of Health Stroke Scale (NIHSS), infarct volume. On the contrary, we observed that EMV-miR-125a-5p level was obviously reduced in IS, with the lowest level in acute stage, and was negatively correlated with carotid plaque, IMT, NIHSS scores, infarct volume. EMVs and EMV-miR-125a-5p levels were closely related with large artery atherosclerosis subgroup. Importantly, EMVs and EMV-miR-125a-5p levels could serve as independent risk factors, and receiver operating characteristic curve achieved an area under curve (AUC) of 0.720 and 0.832 for IS, respectively, and elevated to 0.881 after their combination. In IS mouse model, control EMVs or n-EMVs administration could decrease the infarct volume and neurological deficit score, while increase the cerebral blood flow of IS mice compared with vehicle group, while IS EMVs or oxygen and glucose deprivation (OGD)-EMVs administration aggravated the tMCAO induced ischaemic injury. In addition, we observed that OGD EMVmiR-125a-5p could partially ameliorate the OGD EMVs induced brain injury after IS.

Conclusions

These findings demonstrate that circulating EMVs and EMV-miR-125a-5p are closely related with the occurrence, progress, subtypes and severity of IS, and they can serve as innovative biomarkers and therapeutic targets for IS, especially when they are combined.

Von Willebrand factor (vWF) in patients with heart failure with preserved ejection fraction (HFpEF): A retrospective observational study

Heart failure with preserved ejection fraction (HFpEF) is associated with endothelial damage and inflammation. In addition, von Willebrand factor (vWF) has been discovered as a biomarker of endothelial dysfunction. Therefore, the study aims to investigate the association between vWF level and HFpEF. Moreover, we analyzed a potential correlation between vWF and inflammatory factors, such as C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukin (IL)-6. We recruited altogether 272 hospitalized patients from The Fifth Affiliated Hospital of Xinjiang Medical University, 88 of whom were HFpEF patients, 88 were non-heart failure patients, and 96 were healthy controls from the medical examination center of the hospital. Enzyme-linked immunosorbent assay and double antibody sandwich immunochromatography were used for testing vWF, tissue plasminogen activator, galectin-3, nitric oxide, TNF-α, IL-6, and CRP. The HFpEF group's levels of vWF, IL-6, TNF-α, CRP, tissue plasminogen activator, galectin-3, and nitric oxide were statistically higher than those of non-heart failure and healthy control ones (F = 403.563, 21.825, 20.678, 39.609, 35.411, 86.407, 74.605; all P = .000). the highest level of vWF was observed in class IV (New York Heart Association) of HFpEF patients and the significant difference is <.05 (P < .001). An increasing level of vWF were shown in groups (CRP: CRP >3 mg/L group and CRP ≤3 mg/L group; IL-6: IL-6 <7.0 pg/mL group and IL-6 ≥7.0 pg/mL group; TNF-α: TNF-α <5.5 pg/mL group and TNF-α ≥5.5 pg/mL group) with higher level of IL-6, TNF-α, CRP. A multiple regression analysis regarding the relationship of vWF and inflammation markers was performed among the HFpEF patients. Further, statistical significance of the analysis remained after adjusting variables such as body mass index, low-density lipoprotein cholesterol, total cholesterol, coronary artery disease, and type 2 diabetes mellitus (β = 0.406, t = 4.579, P < .001; β = 0.323, t = 3.218, P < .001; β = 0.581, t = 6.922, P < .001). Our study shows that elevated vWF levels are associated with HFpEF, and it may serve as a potential biomarker for HFpEF severity. We also found that increased vWF levels are positively correlated to IL-6, TNF-α, and CRP, which may provide a clue for further researching the pathogenesis of HFpEF.

Sex differences in thrombosis as it affects acute ischemic stroke

Ischemic stroke is a devastating health problem, affecting approximately 800,000 patients in the US every year, making it the leading cause of combined death and disability in the country. Stroke has historically been thought of as predominantly impacting men, however it is becoming increasingly clear that stroke affects women to a greater degree than men. Indeed, women have worse outcomes compared to men following ischemic stroke. Recent clinical advances have shown great promise in acute stroke therapy, with the use of mechanical endovascular thrombectomy (with and without recombinant tissue plasminogen activator; rtPA) greatly improving outcomes. This observation makes it clear that removal of clots and reperfusion, either mechanically or pharmacologically, is critical for improving outcomes of patients following acute ischemic stroke. Despite these promising advances, long-term neurological sequelae persist in the post-stroke population. This review focuses on mechanisms of thrombosis (clot formation) as it pertains to stroke and important sex differences in thrombosis and responses to treatment. Finally, we describe recent data related to new therapeutic approaches to thrombolysis, with a particular focus on von Willebrand Factor (vWF).

The von Willebrand Factor A1 domain mediates thromboinflammation, aggravating ischemic stroke outcome in mice

von Willebrand factor (VWF) plays an important role in ischemic stroke. However, the exact mechanism by which VWF mediates progression of ischemic stroke brain damage is not completely understood. Using flow cytometric analysis of single cell suspensions prepared from brain tissue and immunohistochemistry, we investigated the potential inflammatory mechanisms by which VWF contributes to ischemic stroke brain damage in a mouse model of cerebral ischemia/reperfusion injury. Twenty-four hours after stroke, flow cytometric analysis of brain tissue revealed that overall white blood cell recruitment in the ipsilesional brain hemisphere of VWF KO mice was 2 times lower than WT mice. More detailed analysis showed a specific reduction of proinflammatory monocytes, neutrophils and T-cells in the ischemic brain of VWF KO mice compared to WT mice. Interestingly, histological analysis revealed a substantial number of neutrophils and T-cells still within the microcirculation of the stroke brain, potentially contributing to the no-reflow phenomenon. Specific therapeutic targeting of the VWF A1 domain in WT mice resulted in reduced immune cell numbers in the affected brain and protected mice from ischemic stroke brain damage. More specifically, recruitment of proinflammatory monocytes was reduced two-fold, neutrophil recruitment was reduced five-fold and T-cell recruitment was reduced two-fold in mice treated with a VWF A1-targeting nanobody compared to mice receiving a control nanobody. In conclusion, our data identify a potential role for VWF in the recruitment of proinflammatory monocytes, neutrophils and T-cells to the ischemic brain via a mechanism that is mediated by its A1 domain.

Neurovascular Unit as a Source of Ischemic Stroke Biomarkers-Limitations of Experimental Studies and Perspectives for Clinical Application

Cerebral stroke, which is one of the most frequent causes of mortality and leading cause of disability in developed countries, often leads to devastating and irreversible brain damage. Neurological and neuroradiological diagnosis of stroke, especially in its acute phase, is frequently uncertain or inconclusive. This results in difficulties in identification of patients with poor prognosis or being at high risk for complications. It also makes difficult identification of these stroke patients who could benefit from more aggressive therapies. In contrary to the cardiovascular disease, no single biomarker is available for the ischemic stroke, addressing the abovementioned issues. This justifies the need for identifying of effective diagnostic measures characterized by high specificity and sensitivity. One of the promising avenues in this area is studies on the panels of biomarkers characteristic for processes which occur in different types and phases of ischemic stroke and represent all morphological constituents of the brains' neurovascular unit (NVU). In this review, we present the current state of knowledge concerning already-used or potentially applicable biomarkers of the ischemic stroke. We also discuss the perspectives for identification of biomarkers representative for different types and phases of the ischemic stroke, as well as for different constituents of NVU, which concentration levels correlate with extent of brain damage and patients' neurological status. Finally, a critical analysis of perspectives on further improvement of the ischemic stroke diagnosis is presented.

The Association Between Vascular Inflammation and Depressive Disorder. Causality, Biomarkers and Targeted Treatment

Diabetes, obesity, atherosclerosis, and myocardial infarction are frequently co-morbid with major depressive disorder. In the current review, it is argued that vascular inflammation is a factor that is common to all disorders and that an endothelial dysfunction of the blood-brain barrier could be involved in the induction of depression symptoms. Biomarkers for vascular inflammation include a high plasma level of C-reactive protein, soluble cell-adhesion molecules, von Willebrand factor, aldosterone, and proinflammatory cytokines like interleukin-6 or tumor necrosis factor α. A further possible biomarker is flow-mediated dilation of the brachial artery. Treatment of vascular inflammation is expected to prevent or to reduce symptoms of depression. Several tentative treatments for this form of depression can be envisioned: eicosapentaenoic acid (EPA), valproate, Vagus-nerve stimulation, nicotinic α7 agonists, and agonists of the cannabinoid CB₂-receptor.

Changes in Plasma von Willebrand Factor and Cellular Fibronectin in MRI-Defined Traumatic Microvascular Injury

The neuropathology of traumatic brain injury (TB) is diverse, including primary injury to neurons, axons, glial cells, vascular structures, and secondary processes, such as edema and inflammation that vary between individual patients. Traumatic microvascular injury is an important endophenotype of TBI-related injury. We studied patients who sustained a TBI requiring ER evaluation and had an MRI performed within 48 h of injury. We classified patients into 3 groups based on their MRI findings: (1) those that had evidence of traumatic microvascular injury on susceptibility or diffusion weighted MRI sequences without frank hemorrhage [Traumatic Vascular Injury (TVI) group; 20 subjects]. (2) those who had evidence of intraparenchymal, subdural, epidural, or subarachnoid hemorrhage [Traumatic Hemorrhage (TH) group; 26 subjects], and (3) those who had no traumatic injuries detected by MRI [MRI-negative group; 30 subjects]. We then measured plasma protein biomarkers of vascular injury [von Willebrand Factor (vWF) or cellular fibronectin (cFn)] and axonal injury (phosphorylated neurofilament heavy chain; pNF-H). We found that the TVI group was characterized by decreased expression of plasma vWF (p < 0.05 compared to MRI-negative group; p < 0.00001 compared to TH group) ≤48 h after injury. cFN was no different between groups ≤48 h after injury, but was increased in the TVI group compared to the MRI-negative (p < 0.00001) and TH (p < 0.00001) groups when measured >48 h from injury. pNF-H was increased in both the TH and TVI groups compared to the MRI-negative group ≤48 h from injury. When we used the MRI grouping and molecular biomarkers in a model to predict Glasgow Outcome Scale-Extended (GOS-E) score at 30–90 days, we found that inclusion of the imaging data and biomarkers substantially improved the ability to predict a good outcome over clinical information alone. These data indicate that there is a distinct, vascular-predominant endophenotype in a subset of patients who sustain a TBI and that these injuries are characterized by a specific biomarker profile. Further work to will be needed to determine whether these biomarkers can be useful as predictive and pharmacodynamic biomarkers for vascular-directed therapies after TBI.

Von Willebrand factor contribution to pathophysiology outside of von Willebrand disease

VWF is a procoagulant protein that plays a central role in the initiation of platelets aggregate formation and thrombosis. While von Willebrand disease has long been known to result from qualitative and quantitative deficiencies of VWF, it is recently that contribution of elevated levels of VWF to various pathological conditions including thrombosis, inflammation, angiogenesis, and cancer metastasis has been appreciated. Here, we discuss contribution of elevated levels of VWF to various thrombotic and nonthrombotic pathological conditions.

Cellular stress induces erythrocyte assembly on intravascular von Willebrand factor strings and promotes microangiopathy

Microangiopathy with subsequent organ damage represents a major complication in several diseases. The mechanisms leading to microvascular occlusion include von Willebrand factor (VWF), notably the formation of ultra-large von Willebrand factor fibers (ULVWFs) and platelet aggregation. To date, the contribution of erythrocytes to vascular occlusion is incompletely clarified. We investigated the platelet-independent interaction between stressed erythrocytes and ULVWFs and its consequences for microcirculation and organ function under dynamic conditions. In response to shear stress, erythrocytes interacted strongly with VWF to initiate the formation of ULVWF/erythrocyte aggregates via the binding of Annexin V to the VWF A1 domain. VWF-erythrocyte adhesion was attenuated by heparin and the VWF-specific protease ADAMTS13. In an in vivo model of renal ischemia/reperfusion injury, erythrocytes adhered to capillaries of wild-type but not VWF-deficient mice and later resulted in less renal damage. In vivo imaging in mice confirmed the adhesion of stressed erythrocytes to the vessel wall. Moreover, enhanced eryptosis rates and increased VWF binding were detected in blood samples from patients with chronic renal failure. Our study demonstrates that stressed erythrocytes have a pronounced binding affinity to ULVWFs. The discovered mechanisms suggest that erythrocytes are essential for the pathogenesis of microangiopathies and renal damage by actively binding to ULVWFs.

Targeting von Willebrand Factor in Ischaemic Stroke: Focus on Clinical Evidence

Despite great efforts in stroke research, disability and recurrence rates in ischaemic stroke remain unacceptably high. To address this issue, one potential target for novel therapeutics is the glycoprotein von Willebrand factor (vWF), which increases in thrombogenicity especially under high shear rates as it bridges between vascular sub-endothelial collagen and platelets. The rationale for vWF as a potential target in stroke comes from four bodies of evidence. (1) Animal models which recapitulate the pathogenesis of stroke and validate the concept of targeting vWF for stroke prevention and the use of the vWF cleavage enzyme ADAMTS13 in acute stroke treatment. (2) Extensive epidemiologic data establishing the prognostic role of vWF in the clinical setting showing that high vWF levels are associated with an increased risk of first stroke, stroke recurrence or stroke-associated mortality. As such, vWF levels may be a suitable marker for further risk stratification to potentially fine-tune current risk prediction models which are mainly based on clinical and imaging data. (3) Genetic studies showing an association between vWF levels and stroke risk on genomic levels. Finally, (4) studies of patients with primary disorders of excess or deficiency of function in the vWF axis (e.g. thrombotic thrombocytopenic purpura and von Willebrand disease, respectively) which demonstrate the crucial role of vWF in atherothrombosis. Therapeutic inhibition of VWF by novel agents appears particularly promising for secondary prevention of stroke recurrence in specific sub-groups of patients such as those suffering from large artery atherosclerosis, as designated according to the TOAST classification.

Verification of a proteomic biomarker panel to diagnose minor stroke and transient ischaemic attack: phase 1 of SpecTRA, a large scale translational study

OBJECTIVE

To derive a plasma biomarker protein panel from a list of 141 candidate proteins which can differentiate transient ischaemic attack (TIA)/minor stroke from non-cerebrovascular (mimic) conditions in emergency department (ED) settings.

DESIGN

Prospective clinical study (#NCT03050099) with up to three timed blood draws no more than 36 h following symptom onset. Plasma samples analysed by multiple reaction monitoring-mass spectrometry (MRM-MS).

PARTICIPANTS

Totally 545 participants suspected of TIA enrolled in the EDs of two urban medical centres.

OUTCOMES

90-day, neurologist-adjudicated diagnosis of TIA informed by clinical and radiological investigations.

RESULTS

The final protein panel consists of 16 proteins whose patterns show differential abundance between TIA and mimic patients. Nine of the proteins were significant univariate predictors of TIA [odds ratio (95% confidence interval)]: L-selectin [0.726 (0.596-0.883)]; Insulin-like growth factor-binding protein 3 [0.727 (0.594-0.889)]; Coagulation factor X [0.740 (0.603-0.908)]; Serum paraoxonase/lactonase 3 [0.763 (0.630-0.924)]; Thrombospondin-1 [1.313 (1.081-1.595)]; Hyaluronan-binding protein 2 [0.776 (0.637-0.945)]; Heparin cofactor 2 [0.775 (0.634-0.947)]; Apolipoprotein B-100 [1.249 (1.037-1.503)]; and von Willebrand factor [1.256 (1.034-1.527)]. The scientific plausibility of the panel proteins is discussed.

CONCLUSIONS

Our panel has the potential to assist ED physicians in distinguishing TIA from mimic patients.

Elevated Factor VIII and von Willebrand Factor Levels Predict Unfavorable Outcome in Stroke Patients Treated with Intravenous Thrombolysis

Introduction

Plasma factor VIII (FVIII) and von Willebrand factor (VWF) levels have been associated with the rate and severity of arterial thrombus formation and have been linked to outcomes following thrombolytic therapy in acute myocardial infarction patients. Here, we aimed to investigate FVIII and VWF levels during the course of thrombolysis in acute ischemic stroke (AIS) patients and to find out whether they predict long-term outcomes.

Materials and methods

Study population included 131 consecutive AIS patients (median age: 69 years, 60.3% men) who underwent i.v. thrombolysis with recombinant tissue plasminogen activator (rt-PA). Blood samples were taken on admission, 1 and 24 h after rt-PA administration to measure FVIII activity and VWF antigen levels. Neurological deficit of patients was determined according to the National Institutes of Health Stroke Scale (NIHSS). ASPECT scores were assessed using computer tomography images taken before and 24 h after thrombolysis. Intracranial hemorrhage was classified according to the European Cooperative Acute Stroke Study (ECASS) II criteria. Long-term functional outcome was determined at 90 days after the event by the modified Rankin scale (mRS).

Results

VWF levels on admission were significantly elevated in case of more severe AIS [median and IQR values: NIHSS <6:189.6% (151.9-233.2%); NIHSS 6-16: 199.6% (176.4-250.8%); NIHSS >16: 247.8% (199.9-353.8%), p = 0.013]; similar, but non-significant trend was observed for FVIII levels. FVIII and VWF levels correlated well on admission (r = 0.748, p < 0.001) but no significant correlation was found immediately after thrombolysis (r = 0.093, p = 0.299), most probably due to plasmin-mediated FVIII degradation. VWF levels at all investigated occasions and FVIII activity before and 24 h after thrombolysis were associated with worse 24 h post-lysis ASPECT scores. In a binary backward logistic regression analysis including age, gender, high-sensitivity C-reactive protein, active smoking, diabetes, and NIHSS >5 on admission, elevated FVIII and VWF levels after thrombolysis were independently associated with poor functional outcomes (mRS ≥ 3) at 90 days (immediately after thrombolysis: FVIII: OR: 7.10, 95% CI: 1.77-28.38, p = 0.006, VWF: OR: 6.31, 95% CI: 1.83-21.73, p = 0.003; 24 h after thrombolysis: FVIII: OR: 4.67, 95% CI: 1.42-15.38, p = 0.011, VWF: OR: 19.02, 95% CI: 1.94-186.99, p = 0.012).

Conclusion

Elevated FVIII activity and VWF antigen levels immediately after lysis and at 24 h post-therapy were shown to have independent prognostic values regarding poor functional outcomes at 90 days.

Current advances in circulating inflammatory biomarkers in atherosclerosis and related cardio-cerebrovascular diseases

Atherosclerosis (AS) is a systemic chronic disease affecting both the coronary and cerebral arteries. Inflammation plays a key role in the initiation and progression of AS, and numerous inflammatory factors have been proposed as potential biomarkers. This article reviews recent research in studies on major circulating inflammatory biomarkers to identify surrogates that may reflect processes associated with AS development and the risk of AS-related vascular events, such as Von Willebrand factor, lectin-like oxidized low-density-lipoprotein receptor-1, soluble urokinase plasminogen activator receptor, regulated upon activation, normal T-cell expressed and secreted, and microparticles, which may provide new perspectives for clinical AS evaluation and risk stratification.

Reduced ADAMTS13 levels in patients with acute and chronic cerebrovascular disease

Von Willebrand Factor (VWF) plays a major role in thrombosis and hemostasis and its thrombogenicity is controlled by ADAMTS13. Whereas increasing evidence shows a clear association between VWF levels and acute ischemic stroke, little is known about a correlation with ADAMTS13. Therefore, the aim of this study was to compare plasma levels of ADAMTS13 between 85 healthy volunteers (HV), 104 patients with acute ischemic stroke and 112 patients with a chronic cerebrovascular disease (CCD). In this case-control study, plasma ADAMTS13 antigen levels were measured by ELISA and plasma VWF levels, measured previously, were next used to calculate VWF:ADAMTS13 ratios. ADAMTS13 levels and VWF:ADAMTS13 ratios were subsequently correlated with key demographic and clinical parameters. ADAMTS13 levels were significantly lower in acute ischemic stroke patients (82.6 ± 21.0%) compared with HV (110.6 ± 26.9%). Also, CCD patients (99.6 ± 24.5%) had significantly lower ADAMTS13 levels compared with HV however these were still higher than in acute stroke patients. Furthermore, when assessing the VWF:ADAMTS13 ratios, an even greater difference was revealed between stroke patients (2.7 ± 1.9), HV (1.1 ± 0.5) and CCD patients (1.7 ± 0.7). The VWF:ADAMTS13 ratio was significantly associated with stroke severity and modality. In conclusion, both in acute and chronic cerebrovascular disease patients, ADAMTS13 levels were significantly decreased, with the lowest ADAMTS13 levels found in acute stroke patients. This difference was even more distinct when the ratio of VWF:ADAMTS13 was considered. These results demonstrate the potentially important involvement of the VWF/ADAMTS13 axis in ischemic stroke.

The Role of von Willebrand Factor in Vascular Inflammation: From Pathogenesis to Targeted Therapy

Beyond its role in hemostasis, von Willebrand factor (VWF) is an emerging mediator of vascular inflammation. Recent studies highlight the involvement of VWF and its regulator, ADAMTS13, in mechanisms that underlie vascular inflammation and immunothrombosis, like leukocyte rolling, adhesion, and extravasation; vascular permeability; ischemia/reperfusion injury; complements activation; and NETosis. The VWF/ADAMTS13 axis is implicated in the pathogenesis of atherosclerosis, promoting plaque formation and inflammation through macrophage and neutrophil recruitment in inflamed lesions. Moreover, VWF and ADAMTS13 have been recently proposed as prognostic biomarkers in cardiovascular, metabolic, and inflammatory diseases, such as diabetes, stroke, myocardial infarction, and sepsis. All these features make VWF an attractive therapeutic target in thromboinflammation. Several lines of research have recently investigated “tailor-made” inhibitors of VWF. Results from animal models and clinical studies support the potent anti-inflammatory and antithrombotic effect of VWF antagonism, providing reassuring data on its safety profile. This review describes the role of VWF in vascular inflammation “from bench to bedside” and provides an updated overview of the drugs that can directly interfere with the VWF/ADAMTS13 axis.

Clinical role of von Willebrand factor in acute ischemic stroke

BACKGROUND

An elevated level of von Willebrand factor (VWF) is associated with an increased risk for coronary heart disease and ischemic stroke. The objective of the study was to determine whether the level of VWF is associated with the cardioembolic subtype of ischemic stroke, stroke severity, and clinical outcome.

PATIENTS AND METHODS

In this study 108 patients suffering from acute ischemic stroke (AIS) were included. According to the etiology of the stroke, patients were classified into the subtype of cardioembolic (CE) stroke and the group with non-CE stroke. Patients with non-CE stroke were further classified into subtype of large vessel disease, subtype of small vessel disease and subtype of cryptogenic stroke. Laboratory tests were performed in the acute phase and VWF was determined for all patients. The National Institutes of Health Stroke Scale (NIHSS) was applied on admission and the modified Rankin scale (MRS) at discharge.

RESULTS

The only significant factor which predicted CE stroke was age (B = 0.077; standard error, SE = 0.026; P = 0.003). The level of VWF was not significantly higher in the group with the cardioembolic stroke compared to the group with non-CE stroke. Patients assessed by NIHSS on admission as the most disabled had significantly higher levels of VWF (B = 0.006; SE = 0.003; P = 0.045). Those with higher scores of MRS at discharge also had significantly increased levels of VWF (B = 0.006; SE = 0.003; P = 0.028).

CONCLUSION

Among the patients with ischemic stroke, levels of VWF were not increased in those with CE stroke. High levels of VWF were associated with greater severity of stroke as well as with poor clinical outcome.

Histones link inflammation and thrombosis through the induction of Weibel-Palade body exocytosis

Essentials Dysregulated DNA and histone release can promote pathological immunothrombosis. Weibel-Palade bodies (WPBs) are sentinel-like organelles that respond to proinflammatory stimuli. Histones induce WPB exocytosis in a caspase, calcium and charge-dependent mechanism. A targetable axis may exist between DNA/histones and WPBs in inflammation and immunothrombosis.

SUMMARY

Background Damage-associated molecular patterns (DAMPs), including molecules such as DNA and histones, are released into the blood following cell death. DAMPs promote a procoagulant phenotype through enhancement of thrombin generation and platelet activation, thereby contributing to immunothrombosis. Weibel-Palade bodies (WPBs) are dynamic endothelial cell organelles that contain procoagulant and proinflammatory mediators, such as von Willebrand factor (VWF), and are released in response to cell stresses. VWF mediates platelet adhesion and aggregation, and has been implicated as a procoagulant component of the innate immune response. Objective To determine the influence of histones and DNA on WPB release, and characterize their association in models of inflammation. Methods We treated C57BL/6J mice and cultured endothelial cells with histones (unfractionated, lysine-rich or arginine-rich) and DNA, and measured WPB exocytosis. We used inhibitors to determine a mechanism of histone-induced WPB release in vitro. We characterized the release of DAMPs and WPBs in response to acute and chronic inflammation in human and murine models. Results and conclusions Histones, but not DNA, induced the release of VWF (1.46-fold) from WBPs and caused thrombocytopenia (0.74-fold), which impaired arterial thrombus formation in mice. Histones induced WPB release from endothelial cells in a caspase-dependent, calcium-dependent and charge-dependent manner, and promoted platelet capture in a flow chamber model of VWF-platelet string formation. The levels of DAMPs and WPB-released proteins were elevated during inflammation, and were positively correlated in chronic inflammation. These studies showed that DAMPs can regulate the function and level of VWF by inducing its release from endothelial WPBs. This DAMP-WPB axis may propagate immunothrombosis associated with inflammation.

Case-control study of platelet glycoprotein receptor Ib and IIb/IIIa expression in patients with acute and chronic cerebrovascular disease

Background

Animal models have been instrumental in defining thrombus formation, including the role of platelet surface glycoprotein (GP) receptors, in acute ischemic stroke (AIS). However, the involvement of GP receptors in human ischemic stroke pathophysiology and their utility as biomarkers for ischemic stroke risk and severity requires elucidation.

Aims

To determine whether platelet GPIb and GPIIb/IIIa receptors are differentially expressed in patients with AIS and chronic cerebrovascular disease (CCD) compared with healthy volunteers (HV) and to identify predictors of GPIb and GPIIb/IIIa expression.

Methods

This was a case—control study of 116 patients with AIS or transient ischemic attack (TIA), 117 patients with CCD, and 104 HV who were enrolled at our University hospital from 2010 to 2013. Blood sampling was performed once in the CCD and HV groups, and at several time points in patients with AIS or TIA. Linear regression and analysis of variance were used to analyze correlations between platelet GPIb and GPIIb/IIIa receptor numbers and demographic and clinical parameters.

Results

GPIb and GPIIb/IIIa receptor numbers did not significantly differ between the AIS, CCD, and HV groups. GPIb receptor expression level correlated significantly with the magnitude of GPIIb/IIIa receptor expression and the neutrophil count. In contrast, GPIIb/IIIa receptor numbers were not associated with peripheral immune-cell sub-population counts. C-reactive protein was an independent predictor of GPIIb/IIIa (not GPIb) receptor numbers.

Conclusions

Platelet GPIb and GPIIb/IIIa receptor numbers did not distinguish between patient or control groups in this study, negating their potential use as a biomarker for predicting stroke risk.