Endothelial contribution to COVID-19: an update on mechanisms and therapeutic implications.

The global propagation of SARS-CoV-2 leads to an unprecedented public health emergency. Despite that the lungs are the primary organ targeted by COVID-19, systemic endothelial inflammation and dysfunction is observed particularly in patients with severe COVID-19, manifested by elevated endothelial injury markers, endotheliitis, and coagulopathy. Here, we review the clinical characteristics of COVID-19 associated endothelial dysfunction; and the likely pathological mechanisms underlying the disease including direct cell entry or indirect immune overreactions after SARS-CoV-2 infection. In addition, we discuss potential biomarkers that might indicate the disease severity, particularly related to the abnormal development of thrombosis that is a fatal vascular complication of severe COVID-19. Furthermore, we summarize clinical trials targeting the direct and indirect pathological pathways after SARS-CoV-2 infection to prevent or inhibit the virus induced endothelial disorders.

Platelets Contribution to Thrombin Generation in Philadelphia-Negative Myeloproliferative Neoplasms: The "Circulating Wound" Model.

Current cytoreductive and antithrombotic strategies in MPNs are mostly based on cell counts and on patient's demographic and clinical history. Despite the numerous studies conducted on platelet function and on the role of plasma factors, an accurate and reliable method to dynamically quantify the hypercoagulability states of these conditions is not yet part of clinical practice. Starting from our experience, and after having sifted through the literature, we propose an in-depth narrative report on the contribution of the clonal platelets of MPNs-rich in tissue factor (TF)-in promoting a perpetual procoagulant mechanism. The whole process results in an unbalanced generation of thrombin and is self-maintained by Protease Activated Receptors (PARs). We chose to define this model as a "circulating wound", as it indisputably links the coagulation, inflammation, and fibrotic progression of the disease, in analogy with what happens in some solid tumours. The platelet contribution to thrombin generation results in triggering a vicious circle supported by the PARs/TGF-beta axis. PAR antagonists could therefore be a good option for target therapy, both to contain the risk of vascular events and to slow the progression of the disease towards end-stage forms. Both the new and old strategies, however, will require tools capable of measuring procoagulant or prohaemorrhagic states in a more extensive and dynamic way to favour a less empirical management of MPNs and their potential clinical complications.

Prognostic Value of Antithrombin Levels in COVID-19 Patients and Impact of Fresh Frozen Plasma Treatment: A Retrospective Study

Objective: The defective interplay between coagulation and inflammation may be the leading cause of intravascular coagulation and organ dysfunction in coronavirus disease-19 (COVID-19) patients. Abnormal coagulation profiles were reported to be associated with poor outcomes. In this study, we assessed the prognostic values of antithrombin (AT) activity levels and the impact of fresh frozen plasma (FFP) treatment on outcome. Materials and Methods: Conventional coagulation parameters as well as AT activity levels and outcomes of 104 consecutive critically ill acute respiratory distress syndrome (ARDS) patients with laboratory-confirmed COVID-19 disease were retrospectively analyzed. Patients with AT activity below 75% were treated with FFP. Maximum AT activity levels achieved in those patients were recorded. Results: AT activity levels at admission were significantly lower in nonsurvivors than survivors (73% vs. 81%). The cutoff level for admission AT activity was 79% and 58% was the lowest AT for survival. The outcome in those patients who had AT activity levels above 75% after FFP treatment was better than that of the nonresponding group. As well as AT, admission values of D-dimer, C-reactive protein, and procalcitonin were coagulation and inflammatory parameters among the mortality risk factors. Conclusion: AT activity could be used as a prognostic marker for survival and organ failure in COVID-19-associated ARDS patients. AT supplementation therapy with FFP in patients with COVID-19-induced hypercoagulopathy may improve thrombosis prophylaxis and thus have an impact on survival.

A rat model of orthopedic injury-induced hypercoagulability and fibrinolytic shutdown.

BACKGROUND: Postinjury hypercoagulability occurs in >25% of injured patients, increasing risk of thromboembolic complications despite chemoprophylaxis. However, few clinically relevant animal models of posttraumatic hypercoagulability exist. We aimed to evaluate a rodent model of bilateral hindlimb injury as a preclinical model of postinjury hypercoagulability. METHODS: Forty Wistar rats were anesthetized with isoflurane: 20 underwent bilateral hindlimb fibula fracture, soft tissue and muscular crush injury, and bone homogenate injection intended to mimic the physiological severity of bilateral femur fracture. Twenty sham rats underwent anesthesia only. Terminal citrated blood samples were drawn at 0, 6, 12, and 24 hours (n = 5 per timed group) for analysis by native thromboelastography in the presence and absence of taurocholic acid to augment fibrinolysis. Plasminogen activator inhibitor 1 and α-2 antiplasmin levels in plasma were assessed via enzyme-linked immunosorbent assay. RESULTS: Injured rats became hypercoagulable relative to baseline by 6 hours based on thromboelastography maximal amplitude (MA) and G (p < 0.005); sham rats became hypercoagulable to a lesser degree by 24 hours (p < 0.005). Compared with sham animals, injured rats were hypercoagulable by MA and G within 6 hours of injury, remained hypercoagulable by MA and G through at least 24 hours (all p < 0.01), and showed impaired fibrinolysis by taurocholic acid LY30 at 12 hours (p = 0.019) and native LY30 at 24 hours (p = 0.045). In terms of antifibrinolytic mediators, α-2 antiplasmin was elevated in trauma animals at 24 hours (p = 0.009), and plasminogen activator inhibitor 1 was elevated in trauma animals at 6 hours (p = 0.004) and 12 hours (p < 0.001) when compared with sham. CONCLUSIONS: Orthopedic injury in rodents induced platelet and overall hypercoagulability within 6 hours and fibrinolytic impairment by 12 to 24 hours, mimicking postinjury hypercoagulability in injured patients. This rodent model of orthopedic injury may serve as a preclinical testing ground for potential therapies to mitigate hypercoagulability, maintain normal fibrinolysis, and prevent thromboembolic complications.

Association of Preoperative Hypercoagulability with Poor Prognosis in Hepatocellular Carcinoma Patients with Microvascular Invasion After Liver Resection: A Multicenter Study.

BACKGROUND: Microvascular invasion (MVI) predicts poor prognosis in patients with hepatocellular carcinoma (HCC). HCC patients with hypercoagulability are prone to develop thrombosis; however, the relationship between preoperative coagulability state, as reflected by the international normalized ratio (INR) level, and MVI remains unclear. METHODS: From January 2009 to December 2012, HCC patients who underwent R0 liver resection (LR) from four cancer centers entered into this study. The overall survival (OS) and recurrence-free survival (RFS) rates were compared using the Kaplan-Meier method and Cox regression analysis. RESULTS: Of the 2509 HCC patients who were included into this study, 1104 were found to have MVI in the resected specimens. These patients were divided into the low (n = 151), normal (n = 796), and high (n = 157) INR subgroups based on the preoperative INR levels. The low INR subgroup had a significantly higher incidence of MVI than the normal or high INR subgroups (61.6% vs. 41.6% vs. 44.6%; p < 0.001). HCC patients with MVI were significantly more likely to have a low preoperative INR level (p < 0.001); the INR level (p < 0.001) was an independent risk factor of OS and RFS. HCC patients with MVI in the low INR subgroup had significantly worse RFS and OS than the normal or high INR subgroups (median RFS 13.5 vs. 20.2 vs. 21.6 months, p < 0.001; median OS 35.5 vs. 59.5 vs. 57.0 months, p < 0.001). CONCLUSIONS: Preoperative hypercoagulability was associated with poor long-term prognosis in HCC patients with MVI after R0 LR.

Cancer-associated stroke: Pathophysiology, detection and management (Review).

Numerous types of cancer have been shown to be associated with either ischemic or hemorrhagic stroke. In this review, the epidemiology and pathophysiology of stroke in cancer patients is discussed, while providing vital information on the diagnosis and management of patients with cancer and stroke. Cancer may mediate stroke pathophysiology either directly or via coagulation disorders that establish a state of hypercoagulation, as well as via infections. Cancer treatment options, such as chemotherapy, radiotherapy and surgery have all been shown to aggravate the risk of stroke as well. The clinical manifestation varies greatly depending upon the underlying cause; however, in general, cancer­associated strokes tend to appear as multifocal in neuroimaging. Furthermore, several serum markers have been identified, such as high D­Dimer levels and fibrin degradation products. Managing cancer patients with stroke is a delicate matter. The cancer should not be considered a contraindication in applying thrombolysis and recombinant tissue plasminogen activator (rTPA) administration, since the risk of hemorrhage in cancer patients has not been reported to be higher than that in the general population. Anticoagulation, on the contrary, should be carefully examined. Clinicians should weigh the benefits and risks of anticoagulation treatment for each patient individually; the new oral anticoagulants appear promising; however, low­molecular­weight heparin remains the first choice. On the whole, stroke is a serious and not a rare complication of malignancy. Clinicians should be adequately trained to handle these patients efficiently.

The interaction effect of angiogenesis and endothelial dysfunction-related gene variants increases the susceptibility of recurrent pregnancy loss.

PURPOSE: The role of genetic polymorphisms in the pathogenesis of recurrent pregnancy loss (RPL) has been studied intensively. Complex diseases, including miscarriage, are believed to have a polygenic basis, and gene-gene interactions can play a significant role in the etiology of the disease. This study was conducted to investigate the association of gene-gene interactions with angiogenesis, endothelial dysfunction-related gene polymorphisms, and RPL. METHODS: A case-control study was conducted with 253 unrelated RPL patients with 2 or more spontaneous pregnancy losses and 339 healthy women with no history of pregnancy complications. Genotyping of single-nucleotide polymorphisms (SNPs) was performed using real-time polymerase chain reaction (real-time PCR), restriction fragment length polymorphism (RFLP), or allele-specific polymerase chain reaction methods. RESULTS: The genotypes 677TT of the MTHFR gene, 936TT, 936CT, and 634CC, 634GC of the VEGF gene, and allele 894T of the NOS3 gene were associated with a predisposition to RPL in the Russian population. A significant role of additive and epistatic effects in the gene-gene interactions of the SNPs of SERPINE-1, ACE, NOS3, MTHFR, and VEGF genes in RPL was demonstrated. CONCLUSIONS: The results showed that gene-gene interactions are important for RPL susceptibility. Additionally, analysis of the genotype combinations of several allelic variants provides more information on RPL risk than analysis of independent polymorphic markers.

[Venous thromboembolism and pancreatic cancer]. / Maladie thromboembolique veineuse et cancer du pancréas.

Pancreatic cancer (PC) is a devastating malignancy with an overall 5-year survival of 8% for all stages combined. Most of the PC patients diagnosed have an advanced disease (40%) or metastatic stage (40%), which eliminates surgery as a potentially curative treatment. The disease course is often complicated by venous thromboembolism (VTE) events, which per se account for significant morbidity and mortality, with significantly worsen survival. PC is associated with the highest risk of VTE among all cancer patients. We review the literature data to address the incidence and clinical outcomes of VTE in PC patients. VTE incidence varies from 5 to 41% according to epidemiological studies and is as high as 57% in postmortem series. Since 2013, international clinical practice guidelines recommend primary thromboprophylaxis with a grade 1B level of evidence as an adjuvant therapy in advanced PC. A recent meta-analysis of randomized controlled trials investigating the benefit and risk of low-molecular-weight heparins (LMWH) in ambulatory advanced PC patients under chemotherapy showed that the incidence of VTE was 2.1% in patients treated with LMWH and 11.2% in controls (risk ratio, 0.18; 95% CI, 0.083-0.39; P<0.0001). In conclusion, improved earlier diagnosis and effective management of VTE, a frequent and life-threatening complication in PC, is warranted to improve PC patient outcomes.

Hemostasis and Thrombosis in the Oldest Old.

There is a growing proportion of the elderly population in the Western world, and these individuals require special considerations regarding a broad variety of aspects, including treatment approaches to illnesses that affect all age groups. The hemostatic system in individuals changes considerably with aging. Specifically, changes in levels of procoagulant and natural anticoagulant factors along with thrombopathy simultaneously create a hypercoagulable state and hemostatic difficulties. Underlying morbidities, such as congestive heart failure, chronic obstructive pulmonary disease, diabetes mellitus, and cancer, increase the risk for venous and arterial thrombosis. This population is also increasingly affected by acquired bleeding disorders, including acquired hemophilia and acquired von Willebrand syndrome, as well as mild congenital bleeding disorders. Real-life data demonstrate that recurrent and fatal venous thromboembolism is the major hemostatic concern in the elderly. The fact that treatment of thrombotic complications increases the bleeding risk also has to be taken into consideration, particularly in the older age group. This remains true in the era of direct oral anticoagulants. In conclusion, maintaining a delicate balance between thrombosis and bleeding risks is the key issue in providing qualified treatment to elderly patients.

Analysis of serum levels and cutaneous expression of lipoprotein (a) in 38 patients with livedoid vasculopathy.

BACKGROUND: Coagulation disorders contribute to the development of livedoid vasculopathy (LV). Elevated plasma levels of lipoprotein(a) [Lp(a)] are an independent risk factor for the development of cardiovascular disease and associated with hypercoagulable states. Increased serum Lp(a) levels have been reported in patients with LV and may have an important role in the pathogenesis of LV. OBJECTIVES: To investigate Lp(a) expression in skin lesions and circulating serum Lp(a) levels in patients with LV. METHODS: Skin biopsy samples from 38 patients (27 women and 11 men) with active lesions diagnosed as LV and 9 samples of normal skin (5 women and 4 men) from control patients without LV were evaluated for skin expression of Lp(a) by immunohistochemistry. Plasma levels of Lp(a) were analyzed by immunoturbidimetry. RESULTS: We found that lesional skin in patients with LV expressed 10-fold higher Lp(a) immunostaining than controls. High plasma levels of Lp(a) were observed in LV patients. We did not find a correlation (P = .02) between expression of Lp(a) in the skin and plasma levels of Lp(a) in patients with LV. CONCLUSIONS: Increased Lp(a) expression in lesional skin of LV patients suggests the role of Lp(a) in the thrombo-occlusive vasculopathy observed in this disease.

Association Between Hypercoagulability and Severe Obstructive Sleep Apnea.

Importance: Obstructive sleep apnea (OSA) is related to the increased risk of cardiovascular disease. Although the pathogenesis of this association remains unclear, an alteration in coagulability is suspected as a link. Objective: To investigate the association between the severity of OSA and blood coagulability. Design, Setting, and Participants: A retrospective cohort study conducted at a tertiary care university hospital evaluated 146 patients with OSA from January 1, 2009, to July 31, 2015. The participants were divided into 4 groups according to the severity of OSA: control, mild, moderate, and severe. Main Outcomes and Measures: Association between the severity of OSA and coagulation test results, including platelet count, bleeding time, prothrombin time (PT) in seconds and as international normalized ratio (INR), and activated partial thromboplastin time. Results: Of the 146 patients, 135 (92.5%) were men; mean (SD) age was 34.8 (11.1) years. The control group included 41 (28.1%) patients; mild OSA, 32 (21.9%); moderate OSA, 30 (20.5%); and severe OSA, 43 (29.5%). Significant correlations were found between the apnea-hypopnea index and the PT seconds (Spearman r coefficient, -0.30; 95% CI, -0.44 to -0.14) and PT INR (Spearman r coefficient, -0.30; 95% CI, -0.44 to -0.14). There were significant differences between the OSA severity groups for PT seconds for the control group (mean, 11.26 [0.78] seconds) vs the moderate OSA group (10.74 [0.62] seconds; mean difference [MD], 0.52; 95% CI, 0.27 to 1.01) and the severe OSA group (10.67 [0.77] seconds; MD, 0.59; 95% CI, 0.14 to 1.03). Significant differences were also noted in PT INR between the control group (1.00 [0.07]) vs the moderate OSA group (0.95 [0.05]; MD, 0.04; 95% CI, 0.01 to 0.07) and the severe OSA group (0.94 [0.07]; MD, 0.05; 95% CI, 0.02 to 0.08). However, there was no significant difference between the control and mild OSA groups in PT seconds. Conclusions and Relevance: These results suggest that patients with moderate to severe OSA have elevated blood coagulability markers compared with healthy individuals, which may contribute to the occurrence of cardiovascular complications.

Congenital limb deficiencies with vascular etiology: Possible association with maternal thrombophilia.

Congenital limb deficiency defects (LDDs) are etiologically heterogeneous. Acquired causes include amniotic bands, teratogens exposure, and chorionic villus sampling before 10 weeks' gestation and intrinsic causes include single-gene disorders and chromosome abnormalities. However, a substantial number of cases, especially terminal transverse deficiency defects, occur without an obvious cause and are ascribed to vascular disruption events. Some studies have found an association between maternal thrombophilia and congenital LDDs. We investigated this association through a review of all prenatally identified LDDs at a major tertiary care center in Toronto, Canada over a 12-year period. Our results showed a higher prevalence of thrombophilias among women with a pregnancy affected with an LDD when compared to the general population [χ2 (3) = 54.63, P < 0.01]. Our research was strengthened by the inclusion of affected pregnancies regardless of outcome, and strict criteria to avoid including LDDs with a non-vascular etiology. Most LDDs were identified during the routine 18-20 week anatomy ultrasound, but some were discovered as early as 13 weeks' gestation. We found an excess of left-sided defects among terminal transverse but not longitudinal deficiencies; additionally, all diagnoses of maternal thrombophilia occurred in the terminal transverse group. Our results support thrombophilia screening in all women with a prenatally diagnosed fetal LDD as well as careful evaluation of the fetal extremities during prenatal ultrasounds in women with a known thrombophilia. © 2016 Wiley Periodicals, Inc.

Coagulopathy of Acute Sepsis.

Coagulopathy is common in acute sepsis and may range from subclinical activation of blood coagulation (hypercoagulability), which may contribute to venous thromboembolism, to acute disseminated intravascular coagulation, characterized by widespread microvascular thrombosis and consumption of platelets and coagulation proteins, eventually causing bleeding. The key event underlying this life-threatening complication is the overwhelming inflammatory host response to the pathogen leading to the overexpression of inflammatory mediators. The latter, along with the microorganism and its derivatives drive the major changes responsible for massive thrombin formation and fibrin deposition: (1) aberrant expression of tissue factor mainly by monocytes-macrophages, (2) impairment of anticoagulant pathways, orchestrated by dysfunctional endothelial cells (ECs), and (3) suppression of fibrinolysis because of the overproduction of plasminogen activator inhibitor-1 by ECs and thrombin-mediated activation of thrombin-activatable fibrinolysis inhibitor. Neutrophils and other cells, upon activation or death, release nuclear materials (neutrophil extracellular traps and/or their components such as histones, DNA, lysosomal enzymes, and High Mobility Group Box-1), which have toxic, proinflammatory and prothrombotic properties thus contributing to clotting dysregulation. The ensuing microvascular thrombosis-ischemia significantly contributes to tissue injury and multiple organ dysfunction syndromes. These insights into the pathogenesis of sepsis-associated coagulopathy may have implications for the development of new diagnostic and therapeutic tools.

Endothelial Dysfunction and Altered Coagulation As Mediators of Thromboembolism in Behçet Disease.

Behçet disease (BD) is a rare multisystem, inflammatory disease of unknown etiology with vascular involvement and associated thrombogenicity. This review aims to describe the involvement of various mediators in endothelial cell damage and in the hypercoagulable state of BD. The scenario of the chronic inflammation present in BD shows an increased oxidative condition that contributes to endothelial cell damage and induces platelet, leukocyte, and endothelial cell activation through the release of proinflammatory cytokines and chemokines. These factors, together with the increased levels of homocysteine observed in BD patients, induce the endothelial cell expression of adhesion molecules (VCAM-1 and ICAM-1) and tissue factor; the release of cytokines, soluble CD40L (sCD40L), matrix metalloproteinase-9, and blood coagulation factor V; the inhibition of fibrinolysis; the disruption of nitric oxide metabolism; and the increase in platelet reactivity and lipid peroxidation. Endothelial cell dysfunction leads to a prothrombotic and antifibrinolytic phenotype in BD patients. Increased levels of homocysteine, fibrinogen, and plasminogen activator inhibitor type 1 seem to be involved in the procoagulant condition of this pathology that has been verified by end-point tests as well as by global coagulation tests.

[Stroke and Cancer: Are Cryptogenic Strokes a Paraneoplastic Syndrome?]. / Schlaganfall und Krebs: Sind kryptogene Schlaganfälle ein paraneoplastisches Syndrom?

Cancer is an independent risk factor for ischemic stroke, and stroke can precede tumour diagnosis by many months. A paraneoplastic hypercoagulability has been implicated. Overall, cancer is a rare cause, but should be suspected in cases of cryptogenic stroke. In patients with cryptogenic stroke, two criteria ­ ischemic lesions in multiple vascular territories and D-dimer values >2,15 µg/ml ­ predict cancer with 100% specificity according to one relevant study. An adenocarcinoma at an advanced stage is identified in many cases, the risk of stroke-recurrence is high. There is a lack of evidence-based recommendations regarding secondary prevention in these cases. In analogy to the guidelines for venous thromboembolism in cancer patients, low molecular weight heparins might be more efficient compared to other anti-clotting agents.

[Association between periodontal disease and cerebrovascular disease. A review of the literature]. / Asociacion entre la enfermedad periodontal y la enfermedad cerebrovascular. Revision de la bibliografia.

Periodontal disease and cerebrovascular disease are two of the most prevalent processes in elderly people. Various studies have shown an association between them, although some methodological differences exist and this difficult the data interpretation. The aim of this paper is to conduct a critical review of the studies published about this association. Eleven prospective studies and 11 retrospective studies are included in this review. We analyse the different methodological outcomes (study population, periodontal diagnosis, cerebrovascular disease definition, adjusted outcomes and odds ratio/relative risk). Furthermore, we review several pathogenic mechanisms implicated in the progression and the relationship between both processes.

TITLE: Asociacion entre la enfermedad periodontal y la enfermedad cerebrovascular. Revision de la bibliografia.La enfermedad periodontal y la enfermedad cerebrovascular son procesos muy prevalentes en personas de avanzada edad. Diversos estudios han demostrado una asociacion entre ambos, aunque existen diferencias metodologicas que dificultan la interpretacion de los resultados. El objetivo de este articulo es realizar una revision critica de los estudios publicados sobre esta asociacion. Se incluyen 11 estudios prospectivos y 11 estudios retrospectivos, y se analizan las distintas variables metodologicas (poblacion de estudio, diagnostico de enfermedad periodontal, definicion de enfermedad cerebrovascular, variables ajustadas, seguimiento y odds ratio/riesgo relativo). Ademas, se analizan diferentes mecanismos patogenicos que pueden influir en la progresion e interrelacion entre ambos procesos.

[Biomolecular markers in cancer-associated thromboembolism]. / Marcadores biomoleculares en la tromboembolia asociada al cáncer.

Patients with cancer have an increased risk of developing thromboembolism, which is associated with increased morbidity and mortality and hinders its clinical management. Cancer generates a hypercoagulable state that increases the generation of thrombin. This coagulation activation, along with the inflammatory changes fostered by the neoplastic cells, favors tumor progression at the local and distal level. In this review, we present the most salient aspects of the pathophysiology of hypercoagulability in cancer and list the hemostatic biomarkers that reflect this biological situation of hypercoagulability. These parameters can be used as risk factors to predict the probability of developing thrombosis, which help identify patients who can benefit from antithrombotic prophylaxis.