vWF Levels Research Articles

Прогностична цінність визначення sST2 та vWF у сироватці крові пацієнтів з артеріальною гіпертензією та на тлі коронавірусної хвороби

Background. The development of the coronavirus disease (COVID-19) occurs against the background of a systemic inflammatory response and can cause an adverse effect on the cardiovascular system. For better diagnosis of disease prognosis, and treatment, determination of sST2 and vWF is import- ant. These markers play an important role in the genesis of thrombosis in the pathophysiology of COVID- 19. Aim of the study. To analyze the prognostic value of sST2 and vWF levels in blood serum of patients with arterial hypertension (AH) and COVID-19. Materials and methods. 71 patients with AH and 16 practically healthy individuals, who were included in the control group, were examined. Patients were divided into two groups: group 1–36 patients with AH who were admit- ted to the hospital with a hypertensive crisis. Group 2 included 35 patients with AH and polysegmental pneumonia on the background of COVID-19. All patients underwent anthropometry, determination of biochemical blood tests, coagulogram, echocardiography (EchoCG), level of sST2 and vWF using ELISA in blood serum. Venous blood sampling was carried out on the 5-7th day after hospitalization against the background of the treatment according to current protocols. Results. The level of sST2 was the highest in the group of patients with AH and COVID-19, while the level of vWF was slightly lower than in patients with AH, which is probably due to the therapy with glucocorticosteroids and low molecular weight heparins. A positive correlation was found between the sST2 level and the size of the left atrium, left ventricle and ejection fraction in patients with AH, while a positive correlation with age was noted in the group of patients with AH and COVID-19 (p < 0.05). Therefore, the level of sST2 was associated with structural changes in the myocardium, which are characteristic of AH and heart failure, which in turn are associated with age-related changes. A positive correlation was established between vWF and the thickness of the posterior wall of the left ventricle, the size of the right ventricle, in patients with AH, while in patients of the group 2, a correlation was found between vWF and the level of leukocytes (p < 0.05). Conclusion. The levels of sST2 and vWF are important markers of disease severity in patients with cardiovascular pathology, as well as COVID-19. In patients with AH and in combination with COVID-19, a significant increase in the concentration of sST2 and vWF was observed compared to practically healthy individuals. Nevertheless, the presence of COVID-19 did not contribute to the emergence of significantly higher values of these markers compared to the group of individuals with AH, which is probably due to the specifics of the infectious pathology treatment.

Lacticaseibacillus rhamnosus CRL1505 Peptidoglycan Modulates the Inflammation-Coagulation Response Triggered by Poly(I:C) in the Respiratory Tract

Lacticaseibacillus rhamnosus CRL1505 beneficially modulates the inflammation-coagulation response during respiratory viral infections. This study evaluated the capacity of the peptidoglycan obtained from the CRL1505 strain (PG-Lr1505) to modulate the immuno-coagulative response triggered by the viral pathogen-associated molecular pattern poly(I:C) in the respiratory tract. Adult BALB/c mice were nasally treated with PG-Lr1505 for two days. Treated and untreated control mice were then nasally challenged with poly(I:C). Mice received three doses of poly(I:C) with a 24 h rest period between each administration. The immuno-coagulative response was studied after the last administration of poly(I:C). The challenge with poly(I:C) significantly increased blood and respiratory pro-inflammatory mediators, decreased prothrombin activity (PT), and increased von Willebrand factor (vWF) levels in plasma. Furthermore, tissue factor (TF), tissue factor pathway inhibitor (TFPI), and thrombomodulin (TM) expressions were increased in the lungs. PG-Lr1505-treated mice showed significant modulation of hemostatic parameters in plasma (PT in %, Control = 71.3 ± 3.8, PG-Lr1505 = 94.0 ± 4.0, p < 0.01) and lungs. Moreover, PG-Lr1505-treated mice demonstrated reduced TF in F4/80 cells from lungs, higher pro-inflammatory mediators, and increased IL-10 compared to poly(I:C) control mice (IL-10 in pg/mL, Control = 379.1 ± 12.1, PG-Lr1505 = 483.9 ± 11.3, p < 0.0001). These changes induced by PG-Lr1505 correlated with a significant reduction in lung tissue damage. Complementary in vitro studies using Raw 264.7 cells confirmed the beneficial effect of PG-Lr1505 on poly(I:C)-induced inflammation, since increased IL-10 expression, as well as reduced damage, production of inflammatory mediators, and hemostatic parameter expressions were observed. In addition, protease-activated receptor-1 (PAR1) activation in lungs and Raw 264.7 cells was observed after TLR3 stimulation, which was differentially modulated by PG-Lr1505. The peptidoglycan from L. rhamnosus CRL1505 is able to regulate inflammation, the procoagulant state, and PAR1 activation in mice and macrophages in the context of the activation of TLR3 signaling pathways, contributing to a beneficial modulation of inflammation-hemostasis crosstalk.

The Relationship between Low Von Willebrand Factor, Type 1 Von Willebrand Disease and Ageing - Novel Insights from the Lovic and Win Cohort Studies

Introduction For many years, there has been debate about how to optimally diagnose type 1 VWD. Initial guidelines proposed that only individuals with plasma VWF levels < 30 IU/dL should be diagnosed with ‘type 1 VWD’. This was revised in recent ASH/ISTH/WFH/NHF panel which recommended that patients with a significant bleeding history and plasma VWF of 30-50 IU/dL should also be diagnosed with type 1 VWD, as opposed to the discrete ‘Low VWF’ entity proposed in previous guidelines. In this study, we investigated whether Low VWF is a discrete clinical entity, or whether it is instead part of an age-dependent type 1 VWD evolving phenotype. Methods We utilized datasets from two renowned national cohort studies - the Low VWF in Ireland Cohort (LoVIC) and Willebrand in the Netherlands (WiN) studies. In the LoVIC study, patients had a personal bleeding history and historically lowest VWF levels in the 30-50 IU/dL range. In the WiN study, patients had either a personal bleeding history or positive family history, combined with historically lowest VWF levels ≤ 30 IU/dL. Based upon levels at study inclusion versus original diagnosis, WiN patients were categorized into three groups - (i) patients with persistent VWF levels <30 IU/dL; (ii) patients with partial correction in VWF levels into the range of 30-50 IU/dL; and (iii) patients with normalization of VWF levels > 50 IU/dL. The FVIII:C/VWF:Ag ratio was used to assess the synthesis/secretion of VWF and the VWFpp/VWF:Ag ratio was used to assess the clearance of VWF. Results In total, 565 patients were included (403 WiN patients with type 1 VWD and 162 LoVIC patients with Low VWF). Mean age at diagnosis was significantly increased in the LoVIC cohort compared to the three WiN subgroups (32.5 years versus 23.3 years, 26.5 years and 25 years respectively; p<0.001). Conversely, there was no difference in age at time of enrollment into both national studies (p=0.532). To assess the significance of age, we first investigated how plasma VWF:Ag varied over time in WiN type 1 VWD patients compared to the LoVIC cohort. Among the total WiN cohort (with initial VWF levels < 30 IU/dL), 47% of subjects (n=188) had VWF levels that remained < 30 IU/dL despite advancing age. Conversely, 30% of type 1 VWD patients (n=121) increased their plasma VWF levels into the Low VWF range (30-50 IU/dL) over time, whereas 23% (n=94) had age-dependent increments that led to complete normalization in VWF levels > 50 IU/dL. Similarly, 39% (n=63) of patients from the LoVIC study had normalization of VWF levels over time. Crucially, we observed that VWF:Ag in Low VWF patients clearly overlapped with those in normalized (> 50 IU/dL) type 1 VWD subjects, indicating that the LoVIC cohort is a subgroup within the WiN normalized subgroup (Figure 1). To further investigate this concept, we performed multiple regression analysis. Importantly, we observed that plasma VWF:Ag in the LoVIC cohort and the WiN normalized (> 50 IU/dL) subgroup would have not been different had they been diagnosed at the same age (difference of β=0.00 (95% CI -0.03 to 0.04)). Cumulatively, these results indicate that significant heterogeneity exists amongst type 1 VWD patients with respect to the effect of ageing on their plasma VWF levels. In addition, our findings demonstrate that because of age-dependent increases in plasma VWF:Ag, the majority of Low VWF patients would have been diagnosed with type 1 VWD had they undergone assessment earlier in life. Consistently, no difference in prevalence of VWF mutation (36.4% vs 22.6% respectively, p=1.000), FVIII:C/VWF:Ag ratio (1.24 ±0.24 vs 1.46 ±0.27 respectively, p=0.444) or VWFpp/VWF:Ag ratio (1.36 ±0.99 vs 1.75 ±0.38 respectively, p=1.000) was found between LoVIC and normalized WiN patients (Figure 2). Contrarily, WiN patients with persistent VWF levels <30 IU/dL had more often VWF gene variants (93.0%), higher FVIII:C/VWF:Ag ratio (2.65 ±1.62) and higher VWFpp/VWF:Ag ratio (6.14 ±7.05) compared to the other groups (Figure 2, p<0.001). Conclusion Our findings clearly demonstrate that Low VWF does not constitute a discrete clinical or pathological entity. Rather, it is part of an age-dependent type 1 VWD evolving phenotype, as demonstrated by the same VWF levels throughout life, genetic background and pathophysiology. This study has direct consequences for VWD diagnosis, the overall understanding of type 1 VWD as an evolving disease and for patients with low VWF/type 1 VWD.

Age Regulates Desmopressin Responses in Patients with Low Von Willebrand Factor and Type 1 Von Willebrand Disease in the Lovic and Win Studies

Introduction Desmopressin is the treatment of choice in many patients with Low VWF and type 1 VWD. However, not all patients respond well to desmopressin. Moreover, desmopressin is contra-indicated in patients > 60 years in some countries. Interestingly however, previous studies have demonstrated that increases in plasma VWF levels seen with ageing are attributable to enhanced VWF biosynthesis coupled with reduced VWF clearance. Therefore, we investigated the hypothesis that Weibel-Palade body stores of VWF and clearance of VWF, and hence desmopressin responses, may vary with ageing. Methods We investigated datasets collected through the previously described Low VWF in Ireland Cohort (LoVIC) and Willebrand in the Netherlands (WiN) studies. All patients included in the LoVIC study had a personal bleeding history and VWF levels in the 30-50 IU/dL range. Conversely, WiN patients had either a personal bleeding history or positive family history, combined with VWF levels ≤ 30 IU/dL. Desmopressin was administered intravenously at a dosage of 0.3 μg/kg (maximum dose capped at 28 μg/kg) or intranasally at a total dosage of 300 μg. Complete desmopressin response was defined according to the 2021 ASH/ISTH/NHF/WFH guideline (i.e. increase of 2 times the baseline and sustained VWF and FVIII activity > 50 IU/dL for at least 4 hours). Results In total, 261 patients were included (178 WiN patients with type 1 VWD and 83 LoVIC patients with Low VWF). Based upon levels at inclusion in the WiN study versus original diagnosis, type 1 VWD patients were categorized into three groups - (i) 69 patients with persistent VWF levels < 30 IU/dL; (ii) 55 patients with partial correction in VWF levels into the 30-50 IU/dL range; and (iii) 54 patients with normalization of VWF levels > 50 IU/dL. Importantly, a complete response to desmopressin was observed in only 58% of WiN patients with persistent VWF levels < 30 IU/dL, whereas 100% of WiN patients with partially corrected or normalized levels and 100% of LoVIC patients had a complete response to desmopressin (p<0.001). Type 1 patients with persistent VWF levels < 30 IU/dL had significantly lower VWF:Ag at all time points after desmopressin compared to the other groups (Fig 1, p<0.001). Unexpectedly, VWF:Ag at 1, 4 and 24 hours after desmopressin was significantly higher in WiN normalized compared to LoVIC patients (Fig 1, p<0.001). Importantly however, the WiN normalized cohort was significantly older at the time of their desmopressin trial than the LoVIC group (41.9 ±13.8 years versus 32.9 ±10.7 years, p=0.002). Therefore, we hypothesized that the difference in VWF responses might be age-dependent. To investigate this concept, desmopressin responses for different age groups were assessed in LoVIC patients and WiN partially corrected and WiN normalized patients. Interestingly, an age-dependent effect on VWF responses at 1, 4 and 24 hours after desmopressin administration was observed (Fig 2). Older patients had both a significantly better initial desmopressin response at 1 hour after desmopressin (Fig 2, p=0.018), and a significantly prolonged half-life of VWF at 4 hours after desmopressin (Fig 2, p=0.004). Together, these data suggest that aging leads to both increased VWF synthesis/secretion and reduced clearance of VWF. Finally, we performed a retrospective cohort study to investigate whether desmopressin response could be utilized to predict which type 1 VWD patients would normalize their plasma VWF levels with aging. We included 94 LoVIC and 185 type 1 WiN patients with a mean follow-up of 9.7 ±3.9 years and 16.9 ±7.4 years respectively. We demonstrate that desmopressin response predicted the normalization of VWF levels with aging with a 100% accuracy (p<0.001). None of the patients with an incomplete response to desmopressin normalized during follow-up, whereas the median time of normalization was 13 years [7-26] in patients with complete response to desmopressin (p<0.001). Conclusion Cumulatively, we demonstrate that desmopressin responses increase significantly in VWD patients and Low VWF patients as they get older. Given our findings, future studies assessing the clinical efficacy and safety of using attenuated desmopressin doses in older patients should be considered. Alternatively, developing additional therapies that can be safely used to trigger secretion of enhanced Weibel-Palade body stores of VWF in older patients may provide novel treatment opportunities.

Genetic Variants Associated with High Plasma Levels of Factor VIII and Von Willebrand Factor in a Family with Thrombotic Episodes

Background: High levels of factor VIII (FVIII) and von Willebrand factor (vWF) have been indicated as independent risk factors for venous thromboembolism. However, the genetic factors responsible for their increase remain still poorly known. In a woman referred to our Thrombosis unit following a venous thrombotic event, very high levels of FVIII and vWF were found at the acute episode and in subsequent measurements. High levels of FVIII and vWF were also detected in other family members, suggesting a possible genetic cause (Figure 1). Aim: To identify variants/genes associated with high levels of FVIII and vWF. Methods: In a large Italian family with high levels of FVIII/vWF and thrombotic episodes, whole-exome sequencing was performed in 12 family members (SureSelect-Agilent). Data were analyzed according to the guidelines of the Broad Institute (https://software.broadinstitute.org/gatk/best-practices/). Variants were annotated (Annovar) and filtered (KGGseq) according to an autosomal dominant inheritance model of high levels of FVIII or vWF. RNA levels were evaluated in PBMCs by qPCR (Thermo Fisher). Results: 20 variants, spread over a 8300-Kb region on chromosome 5, were identified in 12 genes, including the low frequency rs13158382 located upstream of the MIR143/145 genes. Since variants in the promoter of MIR143/145 have been reported to affect their expression and reduced levels of miR-145 have been associated with high vWF, the potential correlation between rs13158382 and vWF levels was evaluated. Lower levels of both miRNAs and higher level of vWF mRNA were measured in family members carrying the variant (n=3) compared to family members without the variant (n=3). Analysis of genetic and expression data from of a larger cohort of individuals from the 1000 Genomes and GEUVADIS project confirmed a statistically significant reduction (p=0.023) of miR-143 in heterozygous subjects (n=35) compared to homozygous wild-type individuals (n=386). Since low levels of pri-miRNA-143/145 were measured in heterozygous family members and structural changes of pre-miR-143 with rs13158382 was predicted by miRVaS tool, the reduction of mature miRNAs might result from a lowered synthesis of pri-miRNAs and/or from an aberrant processing of pre-miRNA. Conclusion: This family-based study revealed a new genetic variant potentially involved in vWF increase by reducing the expression of miR-143/145.

Rates and Predictors of Prophylaxis in Women with Von Willebrand Disease and Heavy Menstrual Bleeding

Background: Women with von Willebrand disease (vWD) suffer from heavy menstrual bleeding (HMB) often complicated by iron deficiency anemia (IDA) and reduced quality of life. Despite the American Society of Hematology (ASH) recommendations for long-term prophylaxis in patients with severe frequent bleeds, prophylaxis remains under-utilized in women with severe HMB. Given the scarcity of data on management of gynecological bleeding, it is critical to examine our practice patterns and identify factors associated with prophylaxis use. Aims: 1) To evaluate the management and outcomes of gynecological bleeding in vWD, including rates of desmopressin (DDAVP) and vWF prophylaxis for HMB and predictors of their use. 2) To examine the association between prophylaxis and severe HMB. Methods: This retrospective cohort study included women ≥18 years diagnosed with vWD in the Northern Alberta Bleeding Disorders Program. We assessed the rates of HMB, severe HMB and IDA, along with their management strategies. Prophylaxis rates with DDAVP and vWF concentrates, as well as predictors of their use, were examined. Severe HMB was defined as HMB requiring Emergency Department (ED) visits, hospitalizations, blood transfusions, or surgical management (dilation & curettage [D&C], endometrial ablation or hysterectomy). IDA was defined as ferritin <30 mcg/L and hemoglobin <120 g/L. Logistic regression was used to examine factors associated with severe HMB. Variables with P-value <0.20 on univariate regression were included in multivariable regression. Results: 168 women were evaluated with a median age of vWD diagnosis of 27 years (IQR 18-38): 140 (81%) type 1, 23 (13%) type 2, and 5 (3%) type 3 vWD. Among those with type 1 vWD, 43 (31%) had baseline vWF levels <0.30 IU/ml, 94 (67%) had vWF levels of 0.30-0.49 IU/ml, and 3 (2%) had missing values. DDAVP response was assessed in 124/140 (89%) type 1 vWD and 13/23 (57%) type 2 vWD. There were 145 (86%) women with HMB, managed most commonly by tranexamic acid (TXA) (112; 77%), followed by hormonal therapy (73; 50%), subcutaneous DDAVP (40; 28%), and levonorgestrel intrauterine system (39; 26%). vWF prophylaxis was used in only 11 (8%) women. Surgical procedures for HMB were common including hysterectomy (28; 19%), endometrial ablation (15; 10%) and D&C (15; 10%). Over a quarter (39; 27%) received iron infusions. Of the 65 (45%) women with a history of IDA, 6 (9%) had persistent IDA >5 years, 6 (9%) had IDA lasting 2-5 years and 53 (65%) had IDA corrected within 2 years. Prophylaxis rates did not differ between the 68 (40%) women with severe HMB and the 77 (53%) with non-severe HMB, with comparable rates of VWF use (9% vs 6%, P=0.60). Compared with women who never received prophylaxis, those who received DDAVP or vWF prophylaxis were more likely to have received TXA (93% vs 70%, P=0.003), iron infusions (43% vs 19%, P=0.004) and to have been diagnosed before 2000 (22% vs 7%, P=0.03) (Table 1). Though non-significant, a higher proportion of type 3 vWD (9% vs 1%, P=0.06) and higher ISTH-BAT (median 8 vs 7, P=0.07) were observed in prophylaxis recipients. On multivariable logistic regression, time from first bleeding symptom to diagnosis (adjusted odds ratio [aOR] 1.04, 95% CI 1.01-1.07) and prophylactic DDAVP use (aOR 2.4, 95% 1.01-5.6) were associated with severe HMB. There was a non-significant trend towards lower odds of severe HMB in patients diagnosed in 2000-2010 and 2011-2021 as compared to pre-2000 (aOR 0.3, 95% 0.1-1.0). Diagnosis before age 18, vWD type and baseline vWF activity were not associated with severe HMB. Conclusion: Women with vWD experience high rates of HMB and its associated complications. In our study, there was a relatively high uptake of DDAVP prophylaxis, however vWF prophylaxis was under-utilized even in those with severe HMB. We failed to demonstrate an impact of either prophylactic therapy on severe HMB, though this may be due to confounding by indication. There was a significant association between prophylactic DDAVP and vWF with other quality of care indicators including TXA and iron infusions. It is unclear if this association is related to practice patterns or patient factors such as access to care or preference for early definitive treatment. Overall, our findings highlight a need to further understand the barriers to prophylaxis use and to consider earlier prophylaxis for severe HMB to decrease bleeding complications and the need for resource-intensive therapies.

The Role of Platelets and von Willebrand Factor in the Procoagulant Phenotype of Inflammatory Bowel Disease.

Although the risk of thrombosis is well documented for inflammatory bowel disease [IBD] patients, the underlying pathological mechanism seems to be different from other thrombotic conditions. Determining the factors responsible for the increased risk of thrombosis in IBD would help to improve the management of this frequent complication. We studied the interplay between platelets, coagulation, and von Willebrand factor [VWF] in 193 IBD patients and in experimental models [acute and chronic] of colitis in wild-type and VWF-deficient mice. We found a platelet-dependent increase in thrombin generation in IBD patients and in our mouse model of colitis. Agglutinated platelets were present in the blood of patients and mice. Interestingly, we observed not only a significant increase in total VWF antigen, but we were also able to detect the presence of active VWF [VWF in its platelet-binding conformation; 3.2 ± 2.7 μg/mL] in the plasma of 30% of all IBD patients. In healthy controls, active VWF levels were <0.3 μg/mL. This led us to further explore experimental colitis in VWF-deficient mice and we observed that these mice were protected against the procoagulant state triggered by the colitis. Unexpectedly, these mice also showed a significant worsening of colitis severity in both acute and chronic models. Platelets and VWF [including its active form] appear to be central players in the procoagulant phenotype in IBD. We observed that the role of VWF in haemostasis differs from its role in colonic tissue healing, potentially opening new therapeutic avenues for a life-threatening complication in IBD patients.

Von Willebrand factor hyperactivity affects the outcome of lower limb revascularization in subjects with type 2 diabetes mellitus complicated by diabetic foot vasculopathy: An observational pilot study

Aim of this study is to evaluate any differences in VWF antigen, VWF activity and ADAMTS-13 activity before and after successful and non-successful Percutaneous Transluminal Angioplasty (PTA) in subjects with type 2 diabetes (T2DM) complicated by Chronic limb-threatening ischemia (CLTI) in diabetic foot vasculopathy. MethodsIn this prospective observational pilot study, we enrolled 35 T2DM subjects who underwent lower limb PTA. Transcutaneous oximetry was performed in all patients before and 6 weeks after PTA. The change in oxygen partial pressure (TcpO2) before and after PTA was expressed as TcpO2-delta (ΔTcpO2). VWF antigen, VWF activity and ADAMTS-13 activity were measured before and 6 weeks after PTA; changes were expressed as delta and ratio from baseline. ResultsSubjects with ∆TcpO2 < 15 mmHg presented higher ΔVWF activity (p = 0.050) and lower ADAMTS-13 activity ratio (p = 0.080). Subjects with ∆TcpO2 < 30 mmHg showed lower ADAMTS-13 activity Δ and ratio (p = 0.028). ConclusionsVWF antigen levels and VWF activity may potentially affect PTA outcome. Higher levels of VWF could derive from VWF release as consequence of PTA-induced mechanical endothelial damage and/or oxidative stress-induced modifications of VWF structure with impairment of VWF-ADAMTS13 interactions.

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

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

Impact of transfusion on platelet aggregation and biomarkers in myocardial infarction patients with anemia: an ancillary study of the randomized REALITY trial

Abstract Importance Higher rates of thrombotic events have been reported in patients with myocardial infarction (MI) requiring blood transfusion. The impact of transfusion strategies on biomarkers of thrombosis and inflammation is still unknown. Objective Compare the impact of a liberal vs a restrictive transfusion strategy in anemic MI patients on P2Y12 mediated platelet reactivity and biomarkers of thrombosis and inflammation. Design and Setting: Prespecified ancillary study of the multicentric randomized REALITY trial, performed in 6 French centers between February 2018 and September 2019 (Figure). Patients randomized to a liberal (hemoglobin ≤10g/dL) or a restrictive (hemoglobin ≤8g/dL) transfusion strategy had platelet reactivity measured at baseline and after randomization. Participants: One hundred anemic acute MI patients from the REALITY trial (666 randomized patients). Measurements: Measurements of platelet reactivity included a centralized blinded VASP-PRI assay and PRU measured locally using encrypted VerifyNow assay. Biomarkers of thrombosis (P-selectin, PAI-1, vWF) and inflammation (TNF-α) were also measured. The primary endpoint was the change in the VASP-PRI (difference from baseline and post randomization) between the two randomized groups. Results Among 100 patients included (n=50 in each group), the most frequent P2Y12 inhibitors used was clopidogrel (48%) while 16% of the patients did not receive any P2Y12 inhibitors. Transfused patients received on average 2.4±1.6 units of packed red blood cells. We found no differences between groups in change in P2Y12-mediated platelet aggregation before and after randomization, measured either by the VASP PRI (difference 4.3%; 95% CI (-5.4% to 14.1%)) or by the PRU (difference 23.5; 95% CI (-20.8 to 67.8)). Similar results were found in transfused patients (n=71) regardless of the randomized group, VASP PRI (difference 1.6%; 95% CI (-6.7% to 10.0%)) or PRU (difference -17.6; 95% CI (-41.0 to 5.7)). We did not find an impact of transfusion strategy or transfusion itself in the levels of P-selectin, PAI-1, vWF and TNF-α. Conclusion and Relevance A liberal or a restrictive transfusion strategy does not impact platelet reactivity and biomarkers in MI patients with anemia, supporting the lack of clinically relevant difference in thrombotic risk between both strategies.

Utility of the Platelet Function Analyzer (PFA-100) in Patients with Bleeding Disorder of Unknown Cause

Introduction: Bleeding disorder of unknown cause (BDUC) is a diagnosis of exclusion and patients share a similar phenotype with established mild bleeding disorders (MBDs) such as platelet function defects (PFD), mild von Willebrand disease (VWD), or mild coagulation factor deficiencies (CFD). The integration of global assays, such as the Platelet Function Analyzer (PFA)-100, as screening tools for MBDs lacks universal endorsement and is currently not recommended in clinical routine. While the PFA-100 has demonstrated noteworthy sensitivity in the detection of VWD, data regarding its clinical utility in PFD are conflicting and data on PFA-100 in BDUC patients are scarce. Aims: To evaluate the diagnostic utility of PFA-100 in BDUC compared to other MBDs, and to investigate the influence of various parameters on PFA-100 results. Methods: This study included 821 patients enrolled in the Vienna Bleeding Biobank (VIBB), a single-center cohort study on individuals with non-trivial bleeding tendencies who were referred to our tertiary center until December 2022 (EC 604/2009). Patients under anticoagulation or antiplatelet treatment were excluded. PFA-100® assessments (Dade Behring Inc., Newark, Delaware, USA) were conducted on citric acid anticoagulated whole blood samples obtained at study inclusion using two different cartridges: Dade® PFA-100 Collagen/Epinephrine (EPI) and Dade® PFA-100 Collagen/adenosindiphosphat (ADP; Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany). Results: PFA-100 data of 535 BDUC patients (65%) were compared to those of 79 patients (10%) with VWD, 180 (22%) with PFD, and 27 (3%) with CFD. Clinical characteristics are shown in Table 1. In patients with BDUC, the median (interquartile range) closure time (CT) measured by the PFA-100-EPI assay was 102 seconds (88-117), and 135 seconds (112-163; Table 1) with the PFA-100-ADP assay. The CTs were shorter in BDUC compared to VWD (PFA-100-EPI: p&amp;lt;.001, PFA-100-ADP: &amp;lt;p.001) and PFD (PFA-100-EPI: p&amp;lt;.001, PFA-100-ADP: &amp;lt;p.001), while no significant difference was observed compared to CFD (PFA-100-EPI: p=0.2; PFA-100-ADP: p=0.7). Based on in-house reference ranges, CT was normal in both PFA-100 assays in 180 (34%) of all BDUC patients, while 341 patients (64%) had at least one abnormal CT and 11 patients (2%) had abnormal CTs in both PFA-100 assays. A similar distribution was observed in patients with CFD (no abnormal CT: 33%, 1 abnormal CT: 63%, 2 abnormal CTs: 4%). Statistical analysis revealed a significant difference in the number of pathological CTs between BDUC and VWD (no abnormal CT: 9%, 1 abnormal CT: 58%, 2 abnormal CTs: 33%; p&amp;lt;.001), as well as between BDUC and PFD (no abnormal CT: 24%, 1 abnormal CT: 69%, 2 abnormal CTs: 7%; p=0.003). In respect to bleeding severity, in BDUC patients no correlation was found between CTs in the PFA-100-EPI and PFA-100-ADP assays with the Vicenza bleeding score (PFA-100-EPI Spearman rho (r)=0.06, p=0.06; PFA-100-ADP r=0.02, p=0.6), ISTH-BAT (PFA-100-EPI r= 0.06, p=0.3; PFA-100-ADP r= 0.10, p=0.06), or the number of bleeding manifestations (PFA-100-EPI r=0.01, p=0.81; PFA-100-ADP r=-01, p=0.8). The number of pathological PFA-100 was not associated with specific bleeding symptoms assessed by the Vicenza score in BDUC (data not shown). Using a Tobit regression model, we analyzed the association of clinical and laboratory parameters with prolonged CTs in both PFA-100 assays in BDUC, as shown in Table 2. In multivariable linear regression, reduced hematocrit, lower VWF:Ag/VWF:RCo levels, reduced platelet count and higher fibrinogen levels were associated with longer CTs. Increasing age was additionally associated with a longer CT in PFA-100-ADP. Conclusion: In a minority of BDUC patients CT was prolonged in both PFA-100 (EPI and ADP) assays. PFA-100 was not associated with the bleeding severity or specific symptoms in BDUC. In BDUC patients, lower hematocrit, lower platelet count, lower VWF levels and interestingly higher fibrinogen levels were associated with a prolonged CT. Our descriptive results do not suggest the integration of PFA-100 as screening tool for BDUC patients.

Apelin alleviates sepsis-induced acute lung injury in part by modulating the SIRT1/NLRP3 pathway to inhibit endothelial cell pyroptosis

BackgroundSepsis, an intricate systemic inflammatory syndrome, gives rise to various life-threatening complications, with acute lung injury (ALI) being prominently encountered. ALI, clinically characterized by pulmonary infiltration, hypoxemia, and edema, stands as a prevailing consequence of sepsis. This work sought to elucidate the mechanism of Apelin in mitigating sepsis-induced ALI (siALI). MethodsA mouse sepsis model was constructed by cecal ligation and puncture surgery, followed utilizing histopathological analysis using HE staining. mRNA levels of inflammatory cytokines (IL-1β, IL-6, and TNF-α) were assessed utilizing qRT-PCR, while ELISA was employed to measure the levels of vWF, VEGF, IL-1β, and IL-18. Western blot was conducted to examine protein levels of NLRP3, Caspase-1 p20, GSDMD-N, and SIRT1. To evaluate the extent of endothelial cell (EC) pyroptosis, immunofluorescence co-staining of CD31, NLRP3, and Caspase-1 p20 was fulfilled. Furthermore, TUNEL staining was utilized to ascertain the degree of plasma membrane damage and cell death. ResultsApelin demonstrated its potential in ameliorating siALI in mice by diminishing mRNA expression levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) as well as expression levels of vWF and VEGF. Apelin inhibited protein expression of NLRP3, Caspase-1 p20, and GSDMD-N, indicating that EC pyroptosis was suppressed. Finally, Apelin could upregulate the protein expression of SIRT1. This upregulation led to the inhibition of protein expression of NLRP3, Caspase-1 p20, and GSDMD-N, consequently suppressing EC pyroptosis. As a result, a reduction in the expression of inflammatory cytokines IL-1β and IL-18 ultimately alleviated siALI. ConclusionApelin was confirmed to alleviate siALI partially by modulating SIRT1/NLRP3 pathway to inhibit EC pyroptosis, which dawned on the molecular mechanism of siALI and had important clinical significance for treating ALI effectively.

Role of neutrophil extracellular traps in vascular access thrombosis in hemodialysis patients

BackgroundA patent vascular access (VA) is a lifeline for hemodialysis (HD) patients. However, vascular access is prone to thrombosis, which, if left untreated, can lead to permanent VA loss and increased mortality. Neutrophil extracellular traps (NETs) are known to be involved in intravascular thrombosis. We evaluated the relationship between NETs and VA thrombosis and their impact on VA prognosis. MethodsA total of 189 patients with VA flow problems were enrolled. Among these, 93 patients underwent percutaneous transluminal angioplasty (PTA) for stenosis, and 96 patients underwent PTA with thrombectomy for thrombosis. Plasma nucleosome, myeloperoxidase-DNA complex, and von Willebrand factor (vWF) were measured as markers of circulating NETs and thrombosis risk, respectively. The primary outcome was permanent VA loss and the secondary outcome was recurrent thrombotic occlusion within 6 months. In addition, the presence of NETs in thrombi was evaluated by histopathological analysis. ResultsCirculating nucleosome levels were closely associated with plasma vWF levels (r = 0.172, p = 0.025), and both were higher in thrombectomy cases than in PTA alone cases (nucleosome; 0.83 ± 0.70 vs. 0.35 ± 0.26, p < 0.001, vWF: 9.0 ± 7.6 vs. 7.3 ± 6.2, p = 0.038). The highest quartile of nucleosomes (Q4) was associated with an 18-fold increased rate of access thrombotic occlusion (p < 0.001). In addition, multivariate analysis showed that the rates of permanent access loss (HR 2.77, 95 % CI 1.35–5.77) and recurrent thrombosis (HR 2.35, 95 % CI 1.22–4.54) were much higher in patients with the Q4 nucleosome group than in those with Q1–3. In addition, higher neutrophil infiltration and NET expression in thrombi were also associated with poor VA prognosis. ConclusionsHigher levels of circulating NETs and the amount of NET expression in thrombi may be associated with VA thrombosis and poor VA outcomes.

Transient elastography and von Willebrand factor as predictors of portal hypertension and decompensation in children

Von Willebrand factor antigen (vWFAg), a protein measured to test the level of vWF released from the vascular endothelium has gained much attention as a marker for portal hypertension (PHT) severity. The objectives of this study were to investigate the use of vWFAg as a biomarker along with liver and spleen stiffness measurements by transient elastography as potential predictors of clinically significant varices (CSV), variceal bleeding (VB) and decompensation in children with PHT. This observational prospective cohort study included 117 children (median age 10 [IQR 6-14] years) who underwent oesophagogastroduodenoscopy between January'2012 to November'2021 and a validation group of 33 children who underwent the same procedure between December'2021 to March'2023. Measurements of vWFAg and glycoprotein Ib binding activity of VWF (GPIbR) were available in 97 patients in the study group and in all patients in the validation group.Results: vWFAg and GPIbR were significantly higher in children with CSV (223 IU/dl and 166 IU/dl; p= 0.015 and p= 0.04, respectively) and VB (218 IU/dl and 174 IU/dl; p= 0.077 and p= 0.03, respectively) than in those without CSV or VB, respectively. Ninety-six patients had liver and spleen stiffness measurements. Spleen stiffness was significantly higher in patients with CSV compared to those without CSV (p= 0.003). In a chronic liver disease subgroup, a predictive scoring tool based on vWFAg, GPIbR, platelet count, and spleen/liver stiffness measurements could predict CSV with an AUROC of 0.76 (p= 0.04). This study suggests the predictive value of vWF for CSV and VB increases when combined with spleen stiffness, with AUROCs of 0.88 and 0.82, respectively. Hence, a combination of biomarkers could assist clinicians in diagnosing CSV, preventing unnecessary invasive procedures. Surveillance endoscopies in children with portal hypertension (PHT) have their own risks and non-invasive markers, such as von Willebrand factor antigen, glycoprotein Ib binding activity of VWF (GPIbR), and transient elastography could be used to predict clinically significant varices, variceal bleeding and disease compensation in children with PHT. Such non-invasive markers for PHT and varices are lacking in the paediatric population. The results show that von Willebrand factor and GPIbR along with transient elastography can be used to formulate a scoring system which can be used as a clinical tool by paediatric hepatologists to monitor the progression of PHT and risk of bleeding, and hence to stratify the performance of invasive endoscopic procedures under general anaesthesia. However, there is a need to validate the scoring system in children with portal vein thrombosis and for hepatic decompensation in a multi-centre registry in the future.

PB0818 Impact of ABO Blood Group Genotype on VWF Level in Carriers of Type 3 von Willebrand Disease from the French von Willebrand Disease Reference Center

PB0818 Impact of ABO Blood Group Genotype on VWF Level in Carriers of Type 3 von Willebrand Disease from the French von Willebrand Disease Reference Center

ABO Red Cell Antigens, von Willebrand Factor, Factor VIII and Platelet counts among Hypertensive Patients In Kaduna Metropolis, Kaduna.

Background: von Willebrand Factor and factor VIII have been implicated in the vulnerability of causing hypertension which is related/common to some of the ABO blood group antigens. However, the precise mechanism/role of the von Willebrand Factor and factor VIII in hypertension is unknown. The study is a comparative study that is aimed to determine the association of ABO red cell antigen, von Willebrand factor, Factor VIII, and Platelets among hypertensive patients in Kaduna, Nigeria. Methods: To determine this association, fifty-five (55) hypertensive patients and 28 controls were recruited. A purposive sampling technique was employed in selecting the study participants. Determination of the ABO blood group, vWF, FVIII, and platelets was carried out to establish the frequency and the association of ABO blood type with hypertension. Results: It was established that blood group O (43%) has the highest distribution followed by A, B, and AB (6%) the least. There was no significant difference in vWF(ng/L), FVIII(pg/ml), and platelet count(109/l) between the patients and the controls (454.9 and 456.2), (242.0 and 228.4) and (238.0 and 213.0) respectively, p&gt;0.05. The correlation studies showed a strong association between vWF and FVIII (r - 0.544, P&lt;0.0001). There was a significant difference between males’ and females’ vWF and FVIII (P=0.0013 and 0.0029 respectively), indicating females had a higher level of vWF and FVIII, and therefore at higher risk of developing hypertension. Women should therefore be screened for these parameters as a matter of routine. Conclusion: The risk of developing hypertension based on the parameters considered in this study is independent of the ABO blood group of an individual. There is a need for further studies, to confirm or rule out these findings.

The level of adropin and von Willebrand factor in patients with arterial hypertension, excess body weight, and obesity

Objective. To investigate changes in adropin and von Willebrand factor (vWF) levels in patients with arterial hypertension (AH), excess body weight, and obesity.Material and methods. All patients were divided into two main groups: group 1 included 69 patients with AH and excess body weight; group 2 – 55 people with AH and obesity, and 20 healthy people of the control group. Anthropometric measurement, biochemical blood test, echocardiographic examination of the heart, and enzyme immunoassay (adropin, vWF) were performed.Results. The level of vWF was significantly higher in patients with AH, overweight, and obesity compared to healthy individuals (p=0,001). Meanwhile, the adropin level decreased with increasing BMI. The lowest adropin level was observed in individuals with AH and obesity (p=0,011). Additionally, a significant positive correlation was identified between vWF and the size of the LA (r=0,667; p=0,001), RV (r=0,487; p=0,021), MMLV (r=0,795; p=0,001) and IMMLV (r=0,731; p=0,001), whereas a negative correlation was found with EF (r=-0,461; p=0,031).Conclusions. An increase in vWF level was observed in patients with hypertension, overweight, and obesity which contributes to the emergence of endothelial dysfunction and structural myocardial changes, related to AH. The decrease in adropin level – a regulator of the cardiovascular system functions – was associated with an increase in BMI and elevated BP. Negative correlations were found between adropin and systolic and diastolic blood pressure values. It plays an important role in blood pressure and cardiovascular function regulation.

Comorbid association of obstructive sleep apnea (OSA) and thrombotic primary antiphospholipid syndrome (tPAPS): A more severe phenotype?

ObjectiveWe aimed to evaluate the frequency of obstructive sleep apnea (OSA) in patients with thrombotic primary antiphospholipid syndrome (tPAPS), to investigate the performance of screening tools for OSA in this scenario and to compare clinical/laboratorial differences in tPAPS patients with and without OSA. MethodsWe consecutively enrolled patients with tPAPS to undergo sleep studies using a portable monitor. OSA was defined as apnea-hypopnea index ≥15 events/h. Frequency of OSA in tPAPS was evaluated and compared with age-, gender-, and BMI-matched controls (1:3 ratio) from the Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil). Next, we tested the performance of three different screening tools for assessing OSA in patients with tPAPS. Finally, patients with tPAPS were stratified according to OSA status comparing their clinical and laboratory characteristics (including damage burden measured by Damage Index for Antiphospholipid Syndrome [DIAPS] and biomarkers associated with thrombosis) using standard statistical procedures. ResultsFifty-two patients were included for analysis (females: 82.7%; mean age: 48 ± 14 years; body-mass index: 31.1 ± 6.5 Kg/m2; 25% with moderate-severe OSA). When compared to matched controls from ELSA-Brasil (n = 115), there was no significant differences in the frequencies of OSA (tPAPS: 12/42 [28.6%] vs. controls: 35/115 [30.4%], p = 0.821). Among screening tools, NoSAS had the highest area under ROC curve (AUC 0.806, CI 95% 0.672–0.939, p = 0.001), followed by STOP-Bang (AUC 0.772, CI 95% 0.607–0.938, p = 0.004). Patients with comorbid tPAPS and OSA presented higher levels of von Willebrand factor (vWF) (median 38.9 vs. 32.6, p = 0.038) and DIAPS (median 5 vs. 2, p = 0.020), when compared to those without OSA. OSA remained statistically associated with higher DIAPS, even after controlling for age, disease duration and BMI. ConclusionOSA is common in patients with tPAPS, with rates comparable to a non-referred population. Both NoSAS and STOP-Bang scores seems to be useful for screening OSA in these patients. Patients with tPAPS+OSA had higher damage burden and higher levels of vWF, which might suggest a more severe phenotype of tPAPS in this scenario.

Assessment of α9β1 ıntegrın as a new dıagnostıc and therapeutıc target ın Behcet's dısease.

This study aimed to investigate the roles of α9β1 integrin and its ligands in Behçet's disease (BD) by examining serum levels and gene expressions. 15 healthy controls and 30 BD patients (14 active and 16 inactive) were included in the study. Serum levels of ITGA9, ITGB1, TNC, OPN, VCAM-1, VEGF, TSP1, TGM2, Emilin-1, and vWF, were measured by ELISA. Gene expressions of α9β1 (ITGA9 and ITGB1) and its ligands (TNC and SPP1) were evaluated by RT-PCR. Laboratory findings (CRP, ESR, HGB, WBC, RBC, neutrophil, lymphocyte, PLT, RDW, MPV, PCT, and HLA-B51) were obtained from the electronic database. Active BD patients had higher serum levels of α9β1 integrin and its ligands than inactive patients and healthy controls. No significant difference was observed between healthy controls and inactive patients. Gene expressions of ITGB1 and SPP1 were increased in both patient groups compared to healthy controls. ITGA9 and TNC gene expression levels were lower in the active group than in the inactive group. No noticeable differences were found in ITGB1 and SPP1 gene expressions between the patient groups. BD patients exhibited elevated CRP, ESR, WBC, neutrophil, PLT, and PCT levels, while HGB, RBC, and RDW values were lower than healthy controls. Active patients had higher CRP, ESR, WBC, neutrophil, and PLT levels. Significant positive correlations were found between CRP, ESR, WBC, neutrophil, PLT, PCT and serum levels of α9β1 integrin and its ligands. Increased release of α9β1 integrin and its ligands is associated with BD, suggesting their potential as markers for disease severity.

Association between gut-derived endotoxins and porto-sinusoidal vascular disorder with portal hypertension.

Porto-sinusoidal vascular disorder (PSVD) is characterised by lesions involving portal veins and sinusoids in absence of cirrhosis with an unclear pathophysiology. However, its association with immunodeficiency, bowel disorders and abdominal bacterial infections supports the role of altered intestinal permeability and gut-derived endotoxins. The study aimed at assessing the association between serological markers of increased intestinal permeability, pro-aggregating/procoagulant state and liver injury in PSVD and portal hypertension. Thirty-three patients with biopsy-proven PSVD and portal hypertension and 33 healthy subjects were submitted to a venous blood sampling for the measurement of zonulin and lipopolysaccharides (LPS) as markers of intestinal permeability, of s-Glycoprotein VI, sP-selectin, ADAMTS13 and von Willebrand factor (vWF), as markers of platelet aggregation and microvascular inflammation, factor VIII and F1 + 2 as markers of hypercoagulability. In 17 PSVD patients, histomorphological and immunohistochemical study on liver biopsies was performed. Compared with controls, PSVD patients had higher levels of LPS, zonulin, vWF, factor VIII and sP-selectin, F1 + 2. ADAMTS13 was reduced. Serum LPS correlated with zonulin, sP-selectin, FVIII and vWF. At histological analysis, PSVD specimens had increased LPS localisation, toll-like receptor-4(TLR4)-positive macrophages and platelet number compared with samples from healthy liver donors. TLR4+ macrophage number correlated with portal inflammation and fibrosis. Sinusoid dilation and capillarisation were observed. PSVD biopsies showed signs of biliary damage and reduced ductular reaction without alteration in Sox9+ cell population. PSVD patients display an altered intestinal permeability and endotoxemia correlated to a pro-aggregating/procoagulant state; histologically, PSVD was associated with increased TLR4+ cell involvement and platelet clumps within sinusoids. Our study suggests that LPS-TLR4 pathway could contribute to the pathophysiological basis of PSVD with portal hypertension.