Background: Anabolic androgenic steroids (AAS) are thought to increase venous thromboembolism (VTE) risk. Objectives: We investigated whether AAS influence coagulation parameters associated with... Show moreBackground: Anabolic androgenic steroids (AAS) are thought to increase venous thromboembolism (VTE) risk. Objectives: We investigated whether AAS influence coagulation parameters associated with VTE by assessing their changes during and after AAS use. Methods: The HAARLEM study enrolled 100 male amateur athletes voluntarily starting an AAS cycle between 2015 and 2018. We measured procoagulant and anticoagulant protein levels, D-dimer levels, endogenous thrombin potential (ETP), and clot lysis time (CLT) at baseline and during 2 years of follow-up. Changes in coagulation during AAS cycle, 3 months after its discontinuation, and 1 year after its inclusion compared with baseline were estimated using linear mixed models. The associations between AAS dose and duration of use with these outcomes were studied through adjusted multivariable linear regression. Results: Participants used AAS for a median of 13 weeks (IQR: 10-23) with a median weekly dose of 901 mg (IQR: 634-1345 mg). Mean levels of multiple coagulation factors (F) increased during use compared with baseline, whereas FVIII and von Willebrand factor levels remained unchanged. Protein S and D-dimer showed the biggest increase (22% [95% CI: 15-29] and 1.3-fold [95% CI: 1.2-1.5], respectively). CLT was 8 minutes longer (95% CI: 5-10) and ETP was 165 nM*min (95% CI: -205 to -124) lower during the AAS cycle. A high weekly AAS dose and short cycle duration were associated with changes in protein S and ETP during use. All parameters returned to baseline values 3 months after discontinuation and remained similar after. Conclusion: During AAS use, procoagulant and anticoagulant protein levels increased in a reversible manner. The overall balance did not suggest a clear procoagulant state. Show less
Background: Lower-leg injury and knee arthroscopy are both associated with venous thromboembolism (VTE). The mechanism of VTE in both situations is unknown, including the role of procoagulant... Show moreBackground: Lower-leg injury and knee arthroscopy are both associated with venous thromboembolism (VTE). The mechanism of VTE in both situations is unknown, including the role of procoagulant microparticles. This may provide useful information for individualizing thromboprophylactic treatment in both patient groups. Objective: We aimed to study the effect of (1) lower-leg trauma and (2) knee arthroscopy on procoagulant phospholipid-dependent (PPL) activity plasma levels. Methods: POT-(K)CAST trial participants who did not develop VTE were randomly selected for the current study. Plasma was collected shortly after lower-leg trauma or before and after knee arthroscopy. For aim 1, samples of 67 patients with lower-leg injury were compared with control samples (preoperative samples of 74 patients undergoing arthroscopy). Linear regression was used to obtain mean ratios (natural logarithm retransformed data), adjusted for age, sex, body mass index, infections, and comorbidities. For aim 2, pre- and postoperative samples of 49 patients undergoing arthroscopy were compared using paired t tests. PPL activity was measured using modified activated factor X-dependent PPL clotting assay. Results: For aim 1, PPL activity levels were almost threefold higher in patients with lower-leg injury compared with controls, that is, mean ratio, 2.82 (95% confidence interval [CI], 1.98-4.03). For aim 2, postoperative PPL activity levels did not change significantly, that is, mean change, -0.72 mU/mL (95% Cl, -2.03 to 0.59). Conclusion: Lower-leg trauma was associated with increased plasma levels of PPL activity, in contrast to knee arthroscopy. Lower-leg trauma triggers the release of procoagulant microparticles. Show less
Objective: The Australian snake venom ptFV (Pseudonaja textilis venom-derived factor V) variant retains cofactor function despite APC (activated protein C)-dependent proteolysis. Here, we aimed to... Show moreObjective: The Australian snake venom ptFV (Pseudonaja textilis venom-derived factor V) variant retains cofactor function despite APC (activated protein C)-dependent proteolysis. Here, we aimed to unravel the mechanistic principles by determining the role of the absent Arg306 cleavage site that is required for the inactivation of FVa (mammalian factor Va). Approach and Results: Our findings show that in contrast to human FVa, APC-catalyzed proteolysis of ptFVa at Arg306 and Lys507 does not abrogate ptFVa cofactor function. Remarkably, the structural integrity of APC-proteolyzed ptFVa is maintained indicating that stable noncovalent interactions prevent A2-domain dissociation. Using Molecular Dynamics simulations, we uncovered key regions located in the A1 and A2 domain that may be at the basis of this remarkable characteristic. Conclusions: Taken together, we report a completely novel role for uniquely adapted regions in ptFVa that prevent A2 domain dissociation. As such, these results challenge our current understanding by which strict regulatory mechanisms control FVa activity. Show less
Background Oral postmenopausal hormone therapy (HT) increases the risk of venous thrombosis (VT). We postulated that activated protein C (APC) resistance induced by HT is one of the mechanisms... Show moreBackground Oral postmenopausal hormone therapy (HT) increases the risk of venous thrombosis (VT). We postulated that activated protein C (APC) resistance induced by HT is one of the mechanisms causing VT, and also assessed the role of one of the main determinants of APC resistance (i.e., tissue factor pathway inhibitor [TFPI]).Methods We performed a nested case-control study embedded within two Women's Health Initiative hormone trials. Women were randomized to hormone therapy or placebo. Biomarkers were measured at baseline and after 1 year in 217 cases and 817 controls.Results Increased APC resistance and decreased TFPI at baseline were associated with VT (odds ratio 1.20-2.06). However, women with such prothrombotic profile at baseline did not have further increased risk of VT when randomized to HT compared with placebo. Although there was no change in APC resistance or TFPI in placebo group after 1 year, HT group showed prothrombotic changes in the biomarkers (i.e., an increase in APC resistance) (mean [standard deviation] 0.39 [0.54]) and decrease in TFPI (-0.21 [0.50]: free TFPI, -0.24 [0.22]: TFPI activity -0.22 [0.20]: total TFPI). However, HT induced prothrombotic change in biomarkers did not increase risk of VT.Conclusion Women with prothrombotic levels of APC resistance and TFPI at baseline were not at increased risk of VT when randomized to HT compared with placebo. This suggests that testing for these biomarkers before starting HT is not required. HT led to prothrombotic change in these biomarkers after one year, but this did not relate to increased risk of VT. Show less
Background Best practice for prevention, diagnosis, and management of venous thromboembolism (VTE) in patients with coronavirus disease 2019 (COVID-19) is unknown due to limited published data in... Show moreBackground Best practice for prevention, diagnosis, and management of venous thromboembolism (VTE) in patients with coronavirus disease 2019 (COVID-19) is unknown due to limited published data in this population. Objectives We aimed to assess current global practice and experience in management of COVID-19-associated coagulopathy to identify information to guide prospective and randomized studies. Methods Physicians were queried about their current approach to prophylaxis, diagnosis, and treatment of VTE in patients with COVID-19 using an online survey tool distributed through multiple international organizations between April 10 and 14, 2020. Results Five hundred fifteen physicians from 41 countries responded. The majority of respondents (78%) recommended prophylactic anticoagulation for all hospitalized patients with COVID-19, with most recommending use of low-molecular-weight heparin or unfractionated heparin. Significant practice variation was found regarding the need for dose escalation of anticoagulation outside the setting of confirmed or suspected VTE. Respondents reported the use of bedside testing when unable to perform standard diagnostic imaging for diagnosis of VTE. Two hundred ninety-one respondents reported observing thrombotic complications in their patients, with 64% noting that the complication was pulmonary embolism. Of the 44% of respondents who estimated incidence of thrombosis in patients with COVID-19 in their hospital, estimates ranged widely from 1% to 50%. One hundred seventy-four respondents noted bleeding complications (34% minor bleeding, 14% clinically relevant nonmajor bleeding, and 12% major bleeding). Conclusion Well-designed epidemiologic studies are urgently needed to understand the incidence and risk factors of VTE and bleeding complications in patients with COVID-19. Randomized clinical trials addressing use of anticoagulation are also needed. Show less
Boer, S. de; Bowman, M.; Notley, C.; Mo, A.M.; Lima, P.; Jong, A. de; ... ; Eikenboom, J. 2020
Background Endothelial colony forming cells (ECFCs) derived from peripheral blood can be used to analyze the pathophysiology of vascular diseases ex vivo. However, heterogeneity is observed between... Show moreBackground Endothelial colony forming cells (ECFCs) derived from peripheral blood can be used to analyze the pathophysiology of vascular diseases ex vivo. However, heterogeneity is observed between ECFC clones and this variability needs to be understood and standardized for ECFCs to be used as a cell model for applications in vascular studies. Objective Determine reference characteristics of healthy control ECFCs to generate a valid ex vivo model for vascular disease. Methods Putative ECFCs (n = 47) derived from 21 individual healthy subjects were studied for cell morphology and specific cell characteristics. Clones were analyzed for the production and secretion of von Willebrand factor (VWF), cell proliferation, and the expression of endothelial cell markers. Results Based on morphology, clones were categorized into three groups. Group 1 consisted of clones with classic endothelial cell morphology, whereas groups 2 and 3 contained less condensed cells with increasing cell sizes. All clones had comparable endothelial cell surface expression profiles, with low levels of non-endothelial markers. However, a decrease in CD31 and a group-related increase in CD309 and CD45 expression, combined with a decrease in cell proliferation and VWF production and secretion, was observed in clones in group 3 and to a lesser extent in group 2. Conclusions We observed group-related variations in endothelial cell characteristics when clones lacked the classic endothelial cell morphology. Despite this variation, clones in all groups expressed endothelial cell surface markers. Provided that clones with similar characteristics are compared, we believe ECFCs are a valid ex vivo model to study vascular disease. Show less
Venous thromboembolism (VTE) causes a major disease burden worldwide, so that effective preventive measures are warranted. Although oral anticoagulation is effective in preventing VTE episodes,... Show moreVenous thromboembolism (VTE) causes a major disease burden worldwide, so that effective preventive measures are warranted. Although oral anticoagulation is effective in preventing VTE episodes, bleeding complications are a major concern that may lead to treatment avoidance. Statin therapy, which is widely used for prevention of arterial cardiovascular disease, is a promising alternative treatment for VTE prophylaxis, as the drug may affect hemostasis without increasing the risk of bleeding. In the past years, clinical studies have suggested that statins can interfere with blood coagulation and, in turn, reduce the risk of VTE. These effects, however, are still regarded with skepticism, as the underlying mechanisms by which statins may affect hemostasis in humans are not clear and data showing that statin therapy reduces VTE risk mostly came from observational studies, while only one randomized trial was conducted to evaluate this issue. In this review, the authors summarize the currently available evidence regarding the effect of statin therapy on coagulation and on VTE prevention. Recent randomized data showed that statin therapy, in particular rosuvastatin, leads to decreased levels of coagulation factors in patients with prior VTE. This evidence provides a reasonable basis for interventional studies necessary to establish the efficacy of statins on reducing the risk of incident and recurrent VTE. Show less
