The Underlying Molecular Basis and Mechanisms of Venous Thrombosis in Patients with Osteomyelitis: A Data-Driven Analysis

Objective

Osteomyelitis (OM) is one of the most risky and challenging diseases. Emerging evidence indicates OM is a risk factor for increasing incidence of venous thromboembolism (VTE) development. However, the mechanisms have not been intensively investigated.

Methods

The OM-related dataset GSE30119 and VTE-related datasets GSE19151 and GSE48000 were downloaded from the Gene Expression Omnibus (GEO) database and analyzed to identify the differentially expressed genes (DEGs) (OMGs1 and VTEGs1, respectively). Functional enrichment analyses of Gene Ontology (GO) terms were performed. VTEGs2 and OMGs2 sharing the common GO biological process (GO-BP) ontology between OMGs1 and VTEGs1 were detected. The TRRUST database was used to identify the upstream transcription factors (TFs) that regulate VTEGs2 and OMGs2. The protein-protein interaction (PPI) network between VTEGs2 and OMGs2 was constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) database and then visualized in Cytoscape. Topological properties of the PPI network were calculated by NetworkAnalyzer. The Molecular Complex Detection (MCODE) plugin was utilized to perform module analysis and choose the hub modules of the PPI network.

Results

A total of 587 OMGs1 and 382 VTEGs1 were identified from the related dataset, respectively. GO-BP terms of OMGs1 and shared DGEs1 were mainly enriched in the neutrophil-related immune response process, and the shared GO-BP terms of OMGs1 and VTEGs1 seemed to be focused on cell activation, immune, defense, and inflammatory response to stress or biotic stimulus. 230 VTEGs2, 333 OMGs2, and 13 shared DEGs2 were detected. 3 TF-target gene pairs (SP1-LSP1, SPI1-FCGR1A, and STAT1-FCGR1A) were identified. The PPI network contained 1611 interactions among 467 nodes. The top 10 hub proteins were TP53, IL4, MPO, ELANE, FOS, CD86, HP, SOCS3, ICAM1, and SNRPG. Several core nodes (such as MPO, ELANE, and CAMP) were essential components of the neutrophil extracellular traps (NETs) network.

Conclusion

This is the first data-mining study to explore shared signatures between OM and VTE by the integrated bioinformatic approach, which can help uncover potential biomarkers and therapeutic targets of OM-related VTE.

KLF11 Protects against Venous Thrombosis via Suppressing Tissue Factor Expression

Krüppel-like factors (KLFs) play essential roles in multiple biological functions, including maintaining vascular homeostasis. KLF11, a causative gene for maturity-onset diabetes of the young type 7, inhibits endothelial activation and protects against stroke. However, the role of KLF11 in venous thrombosis remains to be explored. Utilizing stasis-induced murine deep vein thrombosis (DVT) model and cultured endothelial cells (ECs), we identified an increase of KLF11 expression under prothrombotic conditions both in vivo and in vitro. The expression change of thrombosis-related genes was determined by utilizing gain- and loss-of-function approaches to alter KLF11 expression in ECs. Among these genes, KLF11 significantly downregulated tumor necrosis factor-α (TNF-α)-induced tissue factor (TF) gene transcription. Using reporter gene assay, chromatin immunoprecipitation assay, and co-immunoprecipitation, we revealed that KLF11 could reduce TNF-α-induced binding of early growth response 1 (EGR1) to TF gene promoter in ECs. In addition, we demonstrated that conventional Klf11 knockout mice were more susceptible to developing stasis-induced DVT. These results suggest that under prothrombotic conditions, KLF11 downregulates TF gene transcription via inhibition of EGR1 in ECs. In conclusion, KLF11 protects against venous thrombosis, constituting a potential molecular target for treating thrombosis.

Endothelial Nitric Oxide Synthase Gene Polymorphisms Increase Risk of Deep Vein Thrombosis by Altering Homocysteine Levels

BACKGROUND

Deep Vein Thrombosis (DVT) is a multicausal disease involving both acquired as well as genetic factors. Nitric oxide is an influential endogenous factor having its role in the development of deep vein thrombosis. It maintains the vascular integrity and any alterations in its levels may lead to a thrombotic event. It may also modulate homocysteine metabolism to cause hyperhomocysteinemia, which is a prominent risk factor for thrombosis. The objective of the study was to study if endothelial nitric oxide gene polymorphisms, 894G/T, and 2479G/A alter the plasma nitric oxide and homocysteine levels which may eventually increase the risk of deep vein thrombosis.

METHODS

One hundred Doppler ultrasonography and computerized tomography confirmed (for cerebral venous thrombosis), non-related DVT patients (M:F = 58:42; age range = 18 to 61 years) served as the study population. Two hundred hospital staff and their relatives or unrelated attendants of the patients served as the controls. Nitric oxide levels were determined by measuring its metabolites (NOx), and EIA was used to measure homocysteine levels. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for detecting the eNOS polymorphisms 894G/T and 2479G/A.

RESULTS

In total, DVT subjects have 25% higher plasma levels of homocysteine and 37% lower levels of NOx in their circulation when compared to controls. In tertile analysis of nitric oxide and homocysteine levels, 894G/T and 2479G/A polymorphisms were associated with plasma nitric oxide and homocysteine levels. The increased risk of deep vein thrombosis was associated with endothelial nitric oxide gene polymorphisms and nitric oxide levels, but homocysteine levels were not a risk for deep vein thrombosis.

CONCLUSION

The present study demonstrates that 894G/T and 2479G/A polymorphisms interact with lower levels of nitric oxide and higher levels of homocysteine that may possess the risk of deep vein thrombosis.

A Case of a Pediatric Patient With Protein S Heerlen Polymorphism and Deep Venous Thrombosis

Hereditary protein S (PS) deficiency is a rare autosomal dominant disorder with increased risk of venous thromboembolism. The PS Heerlen polymorphism at codon 501 of the PROS1 gene is considered a variant of uncertain significance. It has since been shown that PS Heerlen has a reduced half-life, resulting in reduced levels of free PS. We report a case of an adolescent female with May Thurner syndrome and heterozygous PS Heerlen mutation resulting in a mild PS deficiency and venous thromboembolism. With this nonmodifiable risk factor, the patient received prolonged anticoagulation with strong consideration for lifelong prophylaxis.

Podoplanin promotes tumor growth, platelet aggregation, and venous thrombosis in murine models of ovarian cancer

BACKGROUND

Podoplanin (PDPN) is a sialylated membrane glycoprotein that binds to C-type lectin-like receptor 2 on platelets resulting in platelet activation. PDPN is expressed on lymphatic endothelial cells, perivascular fibroblasts/pericytes, cancer cells, cancer-associated fibroblasts, and tumor stromal cells. PDPN's expression on malignant epithelial cells plays a role in metastasis. Furthermore, the expression of PDPN in brain tumors (high-grade gliomas) was found to correlate with an increased risk of venous thrombosis.

OBJECTIVE

We examined the expression of PDPN and its role in tumor progression and venous thrombosis in ovarian cancer.

METHODS

We used mouse models of ovarian cancer and venous thrombosis.

RESULTS

Ovarian cancer cells express PDPN and release PDPN-rich extracellular vesicles (EVs), and cisplatin and topotecan (chemotherapies commonly used in ovarian cancer) increase the expression of podoplanin in cancer cells. The expression of PDPN in ovarian cancer cells promotes tumor growth in a murine model of ovarian cancer and that knockdown of PDPN gene expression results in smaller primary tumors. Both PDPN-expressing ovarian cancer cells and their EVs cause platelet aggregation. In a mouse model of venous thrombosis, PDPN-expressing EVs released from HeyA8 ovarian cancer cells produce more frequent thrombosis than PDPN-negative EVs derived from PDPN-knockdown HeyA8 cells. Blood clots induced by PDPN-positive EVs contain more platelets than those in blood clots induced by PDPN-negative EVs.

CONCLUSIONS

In summary, our findings demonstrate that the expression of PDPN by ovarian cancer cells promotes tumor growth and venous thrombosis in mice.

α1 -Antitrypsin Z allele and risk of venous thromboembolism in the general population

BACKGROUND

The α1 -antitrypsin Z (rs28929474) allele may lead to alterations in hemostasis either through liver disease or effects on coagulation factors.

OBJECTIVES

To test the hypothesis that the α1 -antitrypsin Z genetic variant is associated with increased risk of venous thromboembolism.

METHODS

A total of 107 075 individuals from the Copenhagen General Population Study were used to test the association of the α1 -antitrypsin Z genetic variant with risk of venous thromboembolism, including deep venous thrombosis and pulmonary embolism, prospectively. Confirmatory analyses were done in the UK Biobank.

RESULTS

During follow-up, venous thromboembolism was diagnosed 6649 times in noncarriers, 436 times in heterozygotes, and 10 times in homozygotes. Hazard ratios for venous thromboembolism in α1 -antitrypsin Z heterozygotes and homozygotes versus noncarriers were 1.1 (95% confidence interval, 1.0-1.2) and 2.2 (1.3-3.7). A one Z allele increase was associated with a hazard ratio for venous thromboembolism of 1.2 (1.0-1.3). The corresponding odds ratio in the UK Biobank was 1.2 (1.1-1.3). The absolute risk of venous thromboembolism associated with α1 -antitrypsin ZZ homozygosity was 7.8% (3.6-12.1). The corresponding estimates were 20.1% (9.1-31.2) for prothrombin G20210A and 15.0% (12.6-17.4) for factor V Leiden. The fraction of venous thromboembolic events attributable to the α1 -antitrypsin Z allele was 0.7% (0.1-1.3). For the prothrombin G20210A and factor V Leiden mutations, population attributable fractions were 1.2% (0.9-1.6) and 10.5% (9.9-11.1).

CONCLUSION

In conclusion, α1 -antitrypsin ZZ homozygosity was associated with a 2.2-fold risk of venous thromboembolism and had a comparable population attributable fraction to prothrombin G20210A.

Rapid identification of a pathogenic variant of PROS1 in a thrombophilic family by whole exome sequencing: A case report

RATIONALE

Venous thrombosis remains a significant problem in modern days. Genetic factors contribute to a subset of patients with venous thrombosis. It is sometimes challenging to identify the underlying culprit in thrombophilic individuals based on traditional laboratory testing and Sanger sequencing.

PATIENT CONCERNS

A thrombophilic family presented with multiple venous thrombosis was examined.

DIAGNOSES

Molecular genetic analysis revealed a pathogenic missense variant of the PROS1 gene. Based on this finding and clinical manifestations, a final diagnosis of protein S deficiency was made.

INTERVENTIONS

Whole exome sequencing (WES) of the proband was performed to identify disease-causing variants. Subsequently, Sanger sequencing was performed to validate the variant in the affected members.

OUTCOMES

Using WES, we rapidly identified a proven pathogenic missense variant (c.1543C > T, p.Arg515Cys) in the sex hormone-binding globulin domain of PROS1, which was confirmed by Sanger sequencing. The decreased level and activity of protein S caused by the variant explained the phenotypes of the family. Patients received rivaroxaban as a long-term anticoagulation therapy and achieved a good prognosis.

LESSONS

Our study suggests WES as a rapid search strategy to identify the genetic factors underlying thrombophilic disorders. Patients with venous thrombosis caused by PROS1 mutations could receive rivaroxaban as the first choice of anticoagulation therapy.

Genome-Wide Association Study Identifies First Locus Associated with Susceptibility to Cerebral Venous Thrombosis

OBJECTIVE

Cerebral venous thrombosis (CVT) is an uncommon form of stroke affecting mostly young individuals. Although genetic factors are thought to play a role in this cerebrovascular condition, its genetic etiology is not well understood.

METHODS

A genome-wide association study was performed to identify genetic variants influencing susceptibility to CVT. A 2-stage genome-wide study was undertaken in 882 Europeans diagnosed with CVT and 1,205 ethnicity-matched control subjects divided into discovery and independent replication datasets.

RESULTS

In the overall case-control cohort, we identified highly significant associations with 37 single nucleotide polymorphisms (SNPs) within the 9q34.2 region. The strongest association was with rs8176645 (combined p = 9.15 × 10-24 ; odds ratio [OR] = 2.01, 95% confidence interval [CI] = 1.76-2.31). The discovery set findings were validated across an independent European cohort. Genetic risk score for this 9q34.2 region increases CVT risk by a pooled estimate OR = 2.65 (95% CI = 2.21-3.20, p = 2.00 × 10-16 ). SNPs within this region were in strong linkage disequilibrium (LD) with coding regions of the ABO gene. The ABO blood group was determined using allele combination of SNPs rs8176746 and rs8176645. Blood groups A, B, or AB, were at 2.85 times (95% CI = 2.32-3.52, p = 2.00 × 10-16 ) increased risk of CVT compared with individuals with blood group O.

INTERPRETATION

We present the first chromosomal region to robustly associate with a genetic susceptibility to CVT. This region more than doubles the likelihood of CVT, a risk greater than any previously identified thrombophilia genetic risk marker. That the identified variant is in strong LD with the coding region of the ABO gene with differences in blood group prevalence provides important new insights into the pathophysiology of CVT. ANN NEUROL 2021;90:777-788.

Role and Mechanism of mir-5189-3p in Deep Vein Thrombosis of Lower Extremities

BACKGROUND

This study is to investigate the role and mechanism of mir-5189-3p in deep vein thrombosis (DVT) in lower extremity.

METHODS

The blood samples were collected from Kazakh patients with DVT in lower extremity and were subjected to microRNA sequencing. Bioinformatics were used to identify mir-5189-3p and its target genes. Dual luciferase reporter assay was used to determine the regulatory effect of mir-5189-3p on JAG1. SD rats were randomly divided into normal control, DVT model, hsa-miR-5189-3p mimics and hsa-miR-5189-3p negative control groups. HE staining was used to observe the pathological changes. TUNEL method was used to observe apoptosis. Western blot was used to detect Bax and Bcl-2 protein expression. Real-time quantitative PCR was used to detect JAG1, Notch1 and Hes1 mRNA.

RESULTS

The target of Has-miR-5189-3p was JAG1. Co-transfection of miR-5189-3p mimics and pmirGLO/JAG1 wild-type plasmid induced significantly decreased luciferase activity. In hsa-miR-5189-3p mimics and hsa-miR-5189-3p negative control groups, there were more nucleated cells in the thrombus tissues, and the organization degree obviously increased. Signs of blood flow recanalization were observed. The apoptosis of hsa-miR-5189-3p mimics and hsa-miR-5189-3p negative control groups was lower than that in DVT model group. Furthermore, mir-5189-3p mimics significantly increased the mRNA levels of JAG1, Notch1 and Hes1. Additionally, mir-5189-3p mimics significantly increased Bcl-2 while decreased Bax protein.

CONCLUSIONS

mir-5189-3p could inhibit apoptosis and promote thrombus organization in DVT possibly via Notch signaling pathway. Mir-5189-3p can be used as a potential target for DVT treatment.

Study on the Effect and Mechanism of miR-185 on Lower Extremity Deep Venous Thrombosis

Lower extremity deep venous thrombosis (LEDVT) is a venous reflux disorder caused by abnormal coagulation of blood. LEDVT can obstruct the lumen and LEDVT is the third vascular disease after cerebrovascular diseases and coronary artery diseases. miRNAs are associated with thrombosis, and miR-185 was reported to affect the proliferation and apoptosis of vascular endothelial cells by regulating receptor of advanced glycation end products (RAGE). However, no study has reported the effect of miR-185 on LEDVT. Here, we studied the effects of miR-185 on the PI3K/AKT and MAPK signaling pathways in the LEDVT cells. The results showed that miR-185 promotes cell proliferation through activating the PI3K/AKT and MAPK signaling pathways and then inhibits tissue factor and fibrin expression to reduce thrombosis. In short, our study provides new ideas and a theoretical basis for research on the prevention, diagnosis, and treatment of LEDVT.

Resistance exercise affects catheter-related thrombosis in rats through miR-92a-3p, oxidative stress and the MAPK/NF-κB pathway

BACKGROUND

MiR-92a-3p and oxidative stress are associated with catheter-related thrombosis (CRT). As a kind of physical intervention, resistance exercise can effectively promote blood circulation. In this study, we investigated the roles of miR-92a-3p, oxidative stress and the P38 mitogen-activated protein kinase/nuclear factor-κB (MAPK/NF-κB) pathway in CRT during resistance exercise.

METHODS

The rat CRT model was used for resistance exercise intervention. Moreover, pathological changes from the right jugular vein to the right auricle were observed under an electron microscope. In addition, reactive oxygen species (ROS) production, malondialdehyde (MDA) activity and heme oxygenase (HO-1) level in rat serum were detected via ELISA. The expression levels of miR-92A-3p and HO-1 in the vascular tissues of the rats were determined via real-time quantitative PCR. Additionally, the expression levels of HO-1, NF-κB P65, p38MAPK and IκBa in the venous tissues of the rats were analysed by Western blot analysis.

RESULTS

The pathological results showed that the thrombosis incidence rate in the CRT + RE group was lower than that in the CRT group. In the CRT group, the expression levels of ROS and MDA, which are markers related to oxidative stress in serum, significantly increased whilst the expression of HO-1 decreased. In the venous tissue, the expression of miR-92a-3p increased, the level of HO-1 decreased, the levels of p38MAPK and NF-κB p65 significantly increased but that of P-IκBa and IκBa significantly decreased. In the CRT + RE group, after administering the resistance exercise intervention, ROS production and MDA activity in serum significantly decreased, the expression level of HO-1 increased and the expression level of miR-92a-3p in the venous tissues significantly decreased and was negatively correlated with that of HO-1. The levels of p38MAPK and NF-κB p65 significantly decreased but that of P- IκBa and IκBa significantly increased.

CONCLUSION

Resistance exercise intervention downregulated miR-92a-3p expression, repaired oxidative stress injury and prevented CRT formation.

Clinical Relevance of VEGFA (rs3025039) +936 C>T Polymorphism in Primary Myelofibrosis: Susceptibility, Clinical Co-Variates, and Outcomes

We evaluated the association of VEGFA rs3025039 polymorphism with clinical co-variates and outcomes in 849 subjects with primary myelofibrosis (PMF) and 250 healthy controls. Minor T-allele frequency was higher in subjects with JAK2^V617F compared with those without JAK2^V617F (18% vs. 13%; p = 0.014). In subjects with JAK2^V617F, the TT genotype was associated at diagnosis with lower platelet concentrations (p = 0.033), higher plasma LDH concentration (p = 0.005), higher blood CD34-positive cells (p = 0.027), lower plasma cholesterol concentration (p = 0.046), and higher concentration of high-sensitivity C-reactive protein (p = 0.018). These associations were not found in subjects with PMF without JAK2^V617F. In subjects with the TT genotype, risk of death was higher compared with subjects with CC/CT genotypes (HR = 2.12 [1.03, 4.35], p = 0.041). Finally, the TT genotype was associated with higher frequency of deep vein thrombosis in typical sites (12.5% vs. 2.5%; OR = 5.46 [1.51, 19.7], p = 0.009). In conclusion, in subjects with PMF, the VEGFA rs3025039 CT or TT genotypes are more common in those with JAK2^V617F than in those without JAK2^V67F mutation and are associated with disease severity, poor prognosis, and risk of deep vein thrombosis.

Association of Thrombosis With Hypereosinophilic Syndrome in Patients With Genetic Alterations

IMPORTANCE

Hypereosinophilic syndromes (HESs) are a rare group of disorders that result in overproduction of eosinophils, leading to tissue damage. Thrombotic complications in HES and associated risk factors in this patient population have not been extensively studied.

OBJECTIVE

To investigate the rates of and risk factors associated with thrombotic events in patients with HES, including markers of clonal hematopoiesis as evidenced by molecular aberrations on next-generation sequencing.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study evaluated patients seen at Brigham and Women's Hospital and Harvard Medical School in Boston, Massachusetts, from January 1, 2015, to January 1, 2020. Patients who had hypereosinophilia with an absolute eosinophil count of 1500 cells/μL or greater on 2 separate occasions at least 1 month apart and who underwent genetic or molecular testing as part of their work-up were included. Patients with secondary eosinophilia were excluded.

MAIN OUTCOMES AND MEASURES

Symptomatic and asymptomatic arterial and venous thrombotic events after the diagnosis of HES and all-cause death.

RESULTS

A total of 71 patients (median age, 58 years [interquartile range (IQR), 43-67 years]; 36 women [51%]; 57 White patients [80%]) were included. Patients had a median follow-up time of 29 months (IQR, 19-49 months). Seventeen patients (24%) had 1 or more thrombotic events, including 11 venous thromboembolic events and 11 arterial thrombotic events (8 patients had ≥1 event and 3 patients had recurrent events). Patients with 1 or more thrombotic events had a higher median Eastern Cooperative Oncology Group performance status (median, 1 [IQR, 1-2] vs 0 [IQR, 0-1]; P = .002), had more frequent cardiac involvement (7 of 17 events [41%] vs 6 of 54 events [11%]; P = .01), more frequently received treatment (17 of 17 events [100%] vs 40 of 54 events [74%]; P = .02), and had more molecular aberrations on next-generation sequencing (12 of 17 [71%] vs 12 of 54 [26%]; P = .003) vs patients without thrombosis. After multivariable analysis, the presence of molecular aberration was associated with increased odds of thrombosis (adjusted odds ratio, 5.4; 95% CI, 1.1-27.7). Death occurred more frequently in patients with thrombotic events compared with those without (6 of 17 [35%] vs 2 of 54 [4%]; P = .002) and in patients with molecular aberrations compared with those without (6 of 24 [25%] vs 1 of 40 [3%]; P = .009), although only thrombotic events were significantly associated with increased odds of death after multivariable analysis.

CONCLUSIONS AND RELEVANCE

In this cohort study, thrombosis was common in patients with HES and was significantly associated with increased risk of death.

Curcumin promotes venous thrombi resolve process in a mouse deep venous thrombosis model via regulating miR-499

BACKGROUND/AIMS

The morbidity of deep venous thrombosis (DVT) is increasing rapidly and the current therapeutic strategies for DVT are unsatisfactory. Accumulating evidence suggest that venous thrombi resolve (VTR) may provide new insights into DVT therapeutic strategies. The aim of this study was to investigate the role of curcumin in VTR process and try to reveal the potential mechanism.

METHODS

Immunofluorescence and HE staining were performed to investigate the therapeutic angiogenesis effect of curcumin in VTR process. Microarray analysis and RT-PCR were performed to examine the expression level of miR-499 in thrombosis after curcumin administration. Cell proliferation, migration and angiogenesis capacity were tested by CCK8 assay, Transwell assay and Tube formation assay, respectively. Dual-luciferase reporter assay (DLR) was used to confirm the connection between miR-499 and paired phosphate and tension homology deleted on chromosome ten (PTEN).

RESULTS

We found that curcumin could effectively promote VTR process by activating angiogenesis in thrombus in vivo. The expression of miR-499 exhibited notably downregulated after curcumin administration. The proangiogenic effect of curcumin in HUVECs could be blocked by miR-499 overexpression. In addition, we confirmed that miR-499 directly target to the 3'UTR region of PTEN.

CONCLUSION

Curcumin promotes VTR process in DVT through activating therapeutic angiogenesis. Mechanically, curcumin promotes therapeutic angiogenesis by regulating miR-499 mediated PTEN/VEGF/Ang-1 signaling pathway.

Transcriptomic Profiling of Femoral Veins in Deep Vein Thrombosis in a Porcine Model

Deep vein thrombosis (DVT) is a severe disease affecting the human venous system, accompanied by high morbidity and mortality rates caused by early and late complications. The study aimed at analyzing the changes in the transcriptome of the femoral vein caused by DVT in the porcine model based on the formation of the thrombus in vivo. The study was performed on 11 castrated male pigs: A thrombus was formed in each left femoral vein in six animals; the remaining five served as a control group. Total RNA was isolated from the left femoral veins of the experimental and control animals. High-throughput RNA sequencing was used to analyze the global changes in the transcriptome of veins with induced DVT. Applied multistep bioinformatics revealed 1474 differentially expressed genes (DEGs): 1019 upregulated and 455 downregulated. Functional Gene Ontology annotated 1220 of DEGs into 225 biological processes, 30 molecular functions and 40 cellular components categories. KEGG analysis disclosed TNF, NF-κB and apoptosis pathways’ overexpression in DVT samples. A thorough analysis of the detected DEGs indicated that a dysregulated inflammatory response and disturbed balance between clotting and anti-clotting factors play a crucial role in the process of DVT.

Epidemiology and Genetics of Venous Thromboembolism and Chronic Venous Disease

Venous disease is a term that broadly covers both venous thromboembolic disease and chronic venous disease. The basic pathophysiology of venous thromboembolism and chronic venous disease differ as venous thromboembolism results from an imbalance of hemostasis and thrombosis while chronic venous disease occurs in the setting of tissue damage because of prolonged venous hypertension. Both diseases are common and account for significant mortality and morbidity, respectively, and collectively make up a large health care burden. Despite both diseases having well-characterized environmental components, it has been known for decades that family history is an important risk factor, implicating a genetic element to a patient's risk. Our understanding of the pathogenesis of these diseases has greatly benefited from an expansion of population genetic studies from pioneering familial studies to large genome-wide association studies; we now have multiple risk loci for each venous disease. In this review, we will highlight the current state of knowledge on the epidemiology and genetics of venous thromboembolism and chronic venous disease and directions for future research.

Severe systemic thrombosis in a young COVID-19 patient with a rare homozygous prothrombin G20210A mutation

COVID-19 patients may experience a hypercoagulable condition, leading to thrombotic events. We describe a patient with COVID-19, carrying a rare homozygous mutation of the prothrombin gene, who developed a severe systemic vein thrombosis. In COVID-19 patients with hypercoagulability disorders the most common inherited and acquired risk factors should be investigated.

Plasminogen activator inhibitor-1 gene promoter 4G/5G polymorphism and risks of peripherally inserted central catheter-related venous thrombosis in patients with lung cancer: a prospective cohort study

PURPOSE

This study investigated the influence of plasminogen activator inhibitor-1 (PAI-1) gene polymorphisms and other contributing clinical factors on peripherally inserted central catheter-related venous thrombosis (PICC-RVT) in Chinese patients with lung cancer.

METHODS

We conducted a prospective study of 237 participants. Blood samples were collected to detect the PAI-1 4G/5G genotype. Venous thromboembolism risk was calculated by the Caprini risk assessment model. Color Doppler ultrasonography was performed every 7 days for 3 weeks to confirm PICC-RVT.

RESULTS

The rate of PICC-RVT was 13.50% (32/237). The 5G/5G, 4G/5G, and 4G/4G genotypes were found in 12.50% vs 17.56%, 59.38% vs 49.27%, and 28.12% vs 34.17% in the thrombus group and the non-thrombus group of the participants. No difference was observed in the distribution frequency of the three genotypes between the thrombus and non-thrombus groups. A higher fibrinogen level (OR 1.194, 95% CI 1.004-1.420, P = 0.045) and a higher Caprini score (OR 1.698, 95% CI 1.103-2.614, P = 0.016) were statistically significant risk factors for PICC-RVT. Compared with patients who underwent a pemetrexed/cisplatin regimen, those who were administered paclitaxel/cisplatin (OR 18.332, 95% CI 2.890-116.278, P = 0.002) or gemcitabine/cisplatin (OR 6.617, 95% CI 1.210-36.180, P = 0.029) were at increased risk of PICC-RVT.

CONCLUSION

Our finding suggested that there is no statistically significant influence of the PAI-1 4G/5G gene variant on PICC-RVT in Chinese patients with lung cancer. However, patients with higher Caprini scores and higher fibrinogen levels are at increased risk for PICC-RVT, as are patients receiving chemotherapy. Clinical staff should carefully perform a risk assessment for patients with PICC. Those with the above risk factors should pay close attention and take timely and effective preventive measures.

Impaired adhesion of neutrophils expressing Slc44a2/HNA-3b to VWF protects against NETosis under venous shear rates

Genome-wide association studies linked expression of the human neutrophil antigen 3b (HNA-3b) epitope on the Slc44a2 protein with a 30% decreased risk of venous thrombosis (VT) in humans. Slc44a2 is a ubiquitous transmembrane protein identified as a receptor for von Willebrand factor (VWF). To explain the link between Slc44a2 and VT, we wanted to determine how Slc44a2 expressing either HNA-3a or HNA-3b on neutrophils could modulate their adhesion and activation on VWF under flow. Transfected HEK293T cells or neutrophils homozygous for the HNA-3a- or HNA-3b-coding allele were purified from healthy donors and perfused in flow chambers coated with VWF at venous shear rates (100 s-1). HNA-3a expression was required for Slc44a2-mediated neutrophil adhesion to VWF at 100 s-1. This adhesion could occur independently of β2 integrin and was enhanced when neutrophils were preactivated with lipopolysaccharide. Moreover, specific shear conditions with high neutrophil concentration could act as a "second hit," inducing the formation of neutrophil extracellular traps. Neutrophil mobilization was also measured by intravital microscopy in venules from SLC44A2-knockout and wild-type mice after histamine-induced endothelial degranulation. Mice lacking Slc44a2 showed a massive reduction in neutrophil recruitment in inflamed mesenteric venules. Our results show that Slc44a2/HNA-3a is important for the adhesion and activation of neutrophils in veins under inflammation and when submitted to specific shears. The fact that neutrophils expressing Slc44a2/HNA-3b have a different response on VWF in the conditions tested could thus explain the association between HNA-3b and a reduced risk for VT in humans.

Coagulation and Fibrinolysis in Obstructive Sleep Apnoea

Obstructive sleep apnoea (OSA) is a common disease which is characterised by repetitive collapse of the upper airways during sleep resulting in chronic intermittent hypoxaemia and frequent microarousals, consequently leading to sympathetic overflow, enhanced oxidative stress, systemic inflammation, and metabolic disturbances. OSA is associated with increased risk for cardiovascular morbidity and mortality, and accelerated coagulation, platelet activation, and impaired fibrinolysis serve the link between OSA and cardiovascular disease. In this article we briefly describe physiological coagulation and fibrinolysis focusing on processes which could be altered in OSA. Then, we discuss how OSA-associated disturbances, such as hypoxaemia, sympathetic system activation, and systemic inflammation, affect these processes. Finally, we critically review the literature on OSA-related changes in markers of coagulation and fibrinolysis, discuss potential reasons for discrepancies, and comment on the clinical implications and future research needs.

PAR4 activation involves extracellular loop 3 and transmembrane residue Thr153

Protease-activated receptor 4 (PAR4) mediates sustained thrombin signaling in platelets and is required for a stable thrombus. PAR4 is activated by proteolysis of the N terminus to expose a tethered ligand. The structural basis for PAR4 activation and the location of its ligand binding site (LBS) are unknown. Using hydrogen/deuterium exchange (H/D exchange), computational modeling, and signaling studies, we determined the molecular mechanism for tethered ligand-mediated PAR4 activation. H/D exchange identified that the LBS is composed of transmembrane 3 (TM3) domain and TM7. Unbiased computational modeling further predicted an interaction between Gly48 from the tethered ligand and Thr153 from the LBS. Mutating Thr153 significantly decreased PAR4 signaling. H/D exchange and modeling also showed that extracellular loop 3 (ECL3) serves as a gatekeeper for the interaction between the tethered ligand and LBS. A naturally occurring sequence variant (P310L, rs2227376) and 2 experimental mutations (S311A and P312L) determined that the rigidity conferred by prolines in ECL3 are essential for PAR4 activation. Finally, we examined the role of the polymorphism at position 310 in venous thromboembolism (VTE) using the International Network Against Venous Thrombosis (INVENT) consortium multi-ancestry genome-wide association study (GWAS) meta-analysis. Individuals with the PAR4 Leu310 allele had a 15% reduction in relative risk for VTE (odds ratio, 0.85; 95% confidence interval, 0.77-0.94) compared with the Pro310 allele. These data are consistent with our H/D exchange, molecular modeling, and signaling studies. In conclusion, we have uncovered the structural basis for PAR4 activation and identified a previously unrecognized role for PAR4 in VTE.

Model-dependent contributions of FXII and FXI to venous thrombosis in mice

BACKGROUND

The intrinsic pathway factors (F) XII and FXI have been shown to contribute to thrombosis in animal models. We assessed the role of FXII and FXI in venous thrombosis in three distinct mouse models.

METHODS

Venous thrombosis was assessed in mice genetically deficient for either FXII or FXI. Three models were used: the inferior vena cava (IVC) stasis, IVC stenosis, and femoral vein electrolytic injury models.

RESULTS

In the IVC stasis model, FXII and FXI deficiency did not affect the size of thrombi but their absence was associated with decreased levels of fibrin(ogen) and an increased level of the neutrophil extracellular trap marker citrullinated histone H3. In contrast, a deficiency of either FXII or FXI resulted in a significant and equivalent reduction in thrombus weight and incidence of thrombus formation in the IVC stenosis model. Thrombi formed in the IVC stenosis model contained significantly higher levels of citrullinated histone H3 compared with the thrombi formed in the IVC stasis model. Deletion of either FXII or FXI also resulted in a significant and equivalent reduction in both fibrin and platelet accumulation in the femoral vein electrolytic injury model.

CONCLUSIONS

Collectively, these data indicate that FXII and FXI contribute to the size of venous thrombosis in models with blood flow and thrombus composition in a stasis model. This study also demonstrates the importance of using multiple mouse models to assess the role of a given protein in venous thrombosis.

Deep vein thrombosis inhibitor may play a therapeutic role in post-stroke patients

BACKGROUND

Deep vein thrombosis (DVT) is associated with stroke. Here, we hypothesize that genes associated with DVT may also play roles in the development of stroke.

METHODS

we firstly conducted large-scale literature based disease-gene relationship data analysis to explore the genes implicated with DVT and stroke. Further, a mega-analysis was conducted for each of these genes that were linked to DVT but not stroke, using 11 independent stroke RNA expression datasets (176 stroke cases and 102 healthy controls). Then, a multiple linear regression (MLR) model was employed to study possible influential factors on the gene expression levels in stroke. After that, a functional pathway analysis was performed to identify the potential biological linkage between stroke and the target genes suggested by mega-analysis.

RESULTS

Over 81.10% genes implicated with DVT also suggested an association with stroke. Among the 24 DVT-specific genes, one DVT-inhibiting gene, SP1, presented significantly increased expression in stroke (LFC = 1.34, p-value = 0.0045). Pathway analysis showed that SP1 may play a therapeutic role in post-stroke patients by promoting multiple of stroke-inhibitors. Moreover, geographical region was indicated as an influential factor on the expression levels of SP1 in stroke samples (p-value = 0.037).

CONCLUSION

Our results suggested that DVT inhibitor SP1 could be a novel therapeutic target gene for post-stroke treatment. Further study of the potential relations between SP1 and stroke was guaranteed.