Predictive value of markers of inflammation in the postthrombotic syndrome: a systematic review: inflammatory biomarkers and PTS

Overall haemostatic potential assay for prediction of outcomes in venous and arterial thrombosis and thrombo-inflammatory diseases

Thromboembolic diseases including arterial and venous thrombosis are common causes of morbidity and mortality globally. Thrombosis frequently recurs and can also complicate many inflammatory conditions through the process of 'thrombo-inflammation,' as evidenced during the COVID-19 pandemic. Current candidate biomarkers for thrombosis prediction, such as D-dimer, have poor predictive efficacy. This limits our capacity to tailor anticoagulation duration individually and may expose lower risk individuals to undue bleeding risk. Global coagulation assays, such as the Overall Haemostatic Potential (OHP) assay, that investigate fibrin generation and fibrinolysis, may provide a more accurate and functional assessment of hypercoagulability. We present a review of fibrin's critical role as a central modulator of thrombotic risk. The results of our studies demonstrating the OHP assay as a predictive biomarker in venous thromboembolism, chronic renal disease, diabetes mellitus, post-thrombotic syndrome, and COVID-19 are discussed. As a comprehensive and global measurement of fibrin generation and fibrinolytic capacity, the OHP assay may be a valuable addition to future multi-modal predictive tools in thrombosis.

Chronic inflammatory diseases increase the risk of post-thrombotic syndrome: A prospective cohort study

BACKGROUND

Clinical management of patients with deep vein thrombosis (DVT) is centered around their risk of recurrent venous thromboembolism (VTE) and post-thrombotic syndrome (PTS). While chronic inflammatory disease (CID) has been established as a risk factor of (recurrent) VTE, research about its potential impact on PTS is lacking.

OBJECTIVES

We aimed to assess the risk of PTS in patients with CID, stratifying for the use of anti-inflammatory treatment.

PATIENTS/METHODS

Consecutive patients with proximal DVT and no active cancer between 2003 and 2018 received a two-year prospective follow-up. CID included inflammatory bowel disease, rheumatic diseases, and gout. Residual venous obstruction (RVO) was assessed by compressive ultrasound after 3-6 months. PTS was diagnosed using the Villalta score after 6-24 months. Hazard ratios (HR) and odds ratios (OR) were adjusted for patient characteristics. The medical ethics committee approved this study.

RESULTS

In total 82 of 801 patients had CID (10.2 %). PTS more often developed in patients with CID (35.4% vs. 18.9 %, p < 0.001) than in those without CID (HR 1.72 [1.15-2.58]). The prevalence of RVO was similar in patients with and without CID (36.8% vs. 41.4 %), and RVO was strongly associated with PTS in patients with CID (OR 3.21 [1.14-9.03]). Moreover, patients with untreated CID (44 %, n = 36) more often had RVO than those with treated CID (51.6% vs. 26.7 %, p = 0.027), and accordingly had a higher risk of PTS (HR 2.18 [1.04-4.58]).

CONCLUSIONS

Patients with CID had an increased risk of developing PTS, especially those without anti-inflammatory treatment, possibly due to an unfavorable impact on RVO-related venous pathology.

Current challenges in the prevention and management of post-thrombotic syndrome-towards improved prevention

Post-thrombotic syndrome (PTS) is a common and potentially debilitating complication of deep vein thrombosis (DVT), affecting up to 50% of DVT patients. The consequence of this chronic condition includes reduced quality of life, increased use of the healthcare system and decreased productivity. The societal impact of this condition is projected to increase, given our ageing population and increased burden of thrombotic diseases. Despite significant recent advances in our understanding of PTS, many unanswered questions remain. Currently, there are few effective and proven options for established PTS; hence, the emphasis should be on instituting effective prevention to reduce the progression to PTS. Effective anticoagulation lowers the risk of PTS, with direct oral anticoagulants appearing to outperform vitamin-K antagonists. However, the evidence for elastic compression stockings and endovascular thrombolysis or thrombectomy techniques remains unclear. Accurate identification of individuals at high risk of developing PTS may also improve the targeting of preventative interventions. This review will examine the current body of evidence regarding PTS, with a focus on preventative strategies as well as novel biomarkers.

Biomarkers and the post-thrombotic syndrome: A systematic review of biomarkers associated with the occurrence of the post-thrombotic syndrome after lower extremity deep venous thrombosis

INTRODUCTION

Post-thrombotic syndrome (PTS) is a frequent chronic complication of deep venous thrombosis (DVT). Biomarkers are potentially valuable clinical tools for handling PTS. The purpose of this review was to examine which biomarkers are associated with the development of PTS in adults with lower extremity DVT.

METHODS

We performed a systematic review of all English language prospective studies of biomarkers and PTS published in PubMed and EMBASE. Studies were included if diagnosing DVT by diagnostic imaging and assessing PTS by clinical scales, for example, the Villalta scale. Biomarkers of thrombophilia and pathological clot properties were not assessed. Data was reported qualitatively.

RESULTS

15 prospective studies were included. Studies varied widely in study design and methods of data analysis. Forty-six different biomarkers were examined, with seven being measured in two or more studies. The most frequently studied biomarkers were D-dimer, CRP, and IL-6. Associations between PTS and D-dimer were predominantly significant, while results on CRP and IL-6 were inconsistent. ICAM-1 was consistently associated with PTS in all studies and at all timepoints. IL-10 was significantly related to PTS development in the largest study and at all time points. Adiponectin, tPA, HRG and TAFI, MMP-1 and -8, and TIMP-1 and -2 were significantly associated with PTS in single studies.

CONCLUSION

(1) Further research on biomarkers and PTS is clearly warranted. (2) Significant differences in study designs made it difficult to draw reliable conclusions regarding individual biomarkers. We suggest the implementation of a standardized framework for the study of biomarkers and PTS, to make comparison of future studies more feasible. (3) D-dimer, ICAM-1, IL-10, MMP-1 and 8, TIMP-1, TIMP-2, and adiponectin are clinical biomarkers of particular interest to include in future studies of PTS. Large scale systemic quantitative proteomic analyses of DVT patients could help identify novel biomarkers of interest in PTS-patients.

Translational insights into mechanisms underlying residual venous obstruction and the role of factor XI, P-selectin and GPVI in recurrent venous thromboembolism

BACKGROUND

Residual venous obstruction (RVO) after deep vein thrombosis (DVT) is considered a risk factor of recurrent venous thromboembolism (VTE), arterial events and post-thrombotic syndrome (PTS). We hypothesized thrombo-inflammatory markers might be associated with RVO and clinical outcomes.

MATERIALS AND METHODS

In a DVT cohort with routine RVO-assessment and 5-year follow-up, patients were invited for blood withdrawal after stopping anticoagulants. Thrombin generation potential, coagulation enzyme:inhibitor complexes, soluble platelet markers and clinical markers were measured in platelet-poor plasma. Associations were represented as odds ratio (OR) or hazard ratio (HR) per standard deviation.

RESULTS

Patients with RVO (102/306, 33 %) had higher rates of PTS (24 vs. 12 %, p = 0.008), but similar rates of recurrence (16 vs. 15 %, p = 0.91) and arterial events (7 vs. 4 %, p = 0.26). RVO was associated with thrombin peak height (OR 1.40 [1.04-1.88]), endogenous thrombin potential (ETP, OR 1.35 [1.02-1.79]), and CRP (OR 1.74 [1.10-2.75]). Recurrent VTE was associated with ETP (HR 1.36 [1.03-1.81]), FXIa:C₁-inhibitor (HR 1.34 [1.04-1.72]), thrombin:antithrombin (HR 1.36 [1.16-1.59]), soluble P-selectin (HR 2.30 [1.69-3.11]), soluble glycoprotein VI (sGPVI, HR 1.30 [1.01-1.69]), D-dimer (HR 1.56 [1.31-1.86]), and factor VIII (HR 1.44 [1.15-1.82]). Arterial events were associated with sGPVI (HR 1.80 [1.25-2.59]). PTS was not associated with any marker.

CONCLUSIONS

Our findings indicate RVO was associated with thrombo-inflammation, but this did not predict clinical outcomes in this setting. Importantly, we found recurrent VTE was associated with ongoing coagulation and platelet activation in patients well beyond the acute phase of DVT. Furthermore, sGPVI indicated an increased risk of arterial events, highlighting the role of platelets in arterial thrombosis following DVT.

Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Imaging Predicts Vein Wall Scarring and Statin Benefit in Murine Venous Thrombosis

BACKGROUND

The postthrombotic syndrome is a common, often morbid sequela of venous thrombosis (VT) that arises from thrombus persistence and inflammatory scarring of juxtaposed vein walls and valves. Noninvasive ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging can measure neutrophil inflammation in VT. Here, we hypothesized (1) early fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) VT inflammation can predict subsequent vein wall scarring (VWS) and (2) statin therapy can reduce FDG-PET VT inflammation and subsequent VWS.

METHODS

C57BL/6J mice (n=75) underwent induction of stasis-induced VT of the inferior vena cava or jugular vein. Inferior vena cava VT mice (n=44) were randomized to daily oral rosuvastatin 5 mg/kg or saline starting at day -1. Subgroups of mice then underwent FDG-PET/CT 2 days after VT induction. On day 14, a subset of mice was euthanized, and VWS was assessed via histology. In vitro studies were further performed on bone marrow-derived neutrophils.

RESULTS

Statin therapy reduced early day 2 FDG-PET VT inflammation, thrombus neutrophil influx, and plasma IL (interleukin)-6 levels. At day 14, statin therapy reduced VWS but did not affect day 2 thrombus mass, cholesterol, or white blood counts, nor reduce day 2 glucose transporter 1 or myeloperoxidase expression in thrombus or in isolated neutrophils. In survival studies, the day 2 FDG-PET VT inflammation signal as measured by mean and maximum standardized uptake values predicted the extent of day 14 VWS (area under the receiver operating characteristic curve =0.82) with a strong correlation coefficient (r) of r=0.73 and r=0.74, respectively. Mediation analyses revealed that 40% of the statin-induced VWS reduction was mediated by reductions in VT inflammation as quantified by FDG-PET.

CONCLUSIONS

Early noninvasive FDG-PET/CT imaging of VT inflammation predicts the magnitude of subsequent VWS and may provide a new translatable approach to identify individuals at risk for postthrombotic syndrome and to assess anti-inflammatory postthrombotic syndrome therapies, such as statins.

ADAMTS13: An Emerging Target in Stroke Therapy

Thrombosis is the predominant underlying mechanism of acute ischemic stroke (AIS). Though thrombolysis with tPA has been proven to be effective in treating AIS within the time window, the majority of AIS patients fail to receive tPA due to various reasons. Current medical therapies for AIS have limited efficacy and pose a risk of intracerebral hemorrhage. ADAMTS13 (a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13) is a metalloprotease that effectively breaks down the von Willebrand Factor (VWF), a key factor in thrombus formation. Previous studies have proven that dysfunction of ADAMTS13 is associated with many diseases. Recently, ADAMTS13 has been reported to be closely related to stroke. In this review, we briefly described the structure of ADAMTS13 and its role in thrombosis, inflammation, as well as angiogenesis. We then focused on the relationship between ADAMTS13 and AIS, ranging from ischemic stroke occurrence, to AIS treatment and prognosis. Based on research findings from in vitro, animal, and clinical studies, we propose that ADAMTS13 is a potential biomarker to guide appropriate treatment for ischemic stroke and a promising therapeutic agent for tPA resistant thrombi.

Prevention and treatment of the post-thrombotic syndrome

Post thrombotic syndrome (PTS) is a common chronic complication of deep vein thrombosis of the leg (DVT). Treatment options are limited therefore emphasis is placed on its prevention. Several risk factors have been recognized, but were so far not used for risk stratification or translation into prediction models. Early interventions did not yet result in more successful preventive treatment strategies; for the acute phase of DVT there is equipoise on the value of elastic compression, as well as on catheter directed thrombolysis. There are no drugs specifically targeted at PTS prevention. The use of anticoagulant medication such as direct oral anticoagulants (DOACs) might decrease PTS incidence, but this needs to be corroborated. Both research into more effective treatment options as well as future PTS management may benefit from a uniform diagnostic strategy and the use of prediction rules to better allocate treatment and thereby increase treatment efficacy.

Postthrombotic Syndrome: Long-Term Sequela of Deep Venous Thrombosis

Postthrombotic syndrome is a common long-term complication of proximal lower extremity deep venous thrombosis, which not only significantly affects the quality of life of patients but also imposes a substantial financial burden on our healthcare system. Due to limited awareness and inability of physicians to recognize and treat this condition early, its prevalence is steadily increasing. In this article, we review the pathophysiology, the risk factors involved, diagnostic workup, and the various management options available to treat this condition.

Development of a clinical prediction model for the postthrombotic syndrome in a prospective cohort of patients with proximal deep vein thrombosis

Essentials We developed a prediction model for postthrombotic syndrome (PTS) after deep vein thrombosis (DVT). High risk predictors were iliac vein DVT, BMI>35 and moderate-severe Villalta category. Patients with a score ≥4 had an odds ratio of 5.9 (95% CI 2.1-16.6) for PTS. SOX-PTS score may select DVT patients for close monitoring or aggressive strategies to treat DVT.

SUMMARY

Background Postthrombotic syndrome (PTS) is a chronic complication that develops in 20-50% of patients after deep vein thrombosis (DVT). Although individual risk factors for PTS have been characterized, the ability to predict which DVT patients are likely to develop PTS remains limited. Objective To develop a clinical prediction score for PTS in patients with DVT. Methods The derivation cohort consisted of participants in the SOX Trial, a randomized double-blind placebo-controlled trial of elastic compression stockings versus placebo stockings worn for 2 years after DVT to prevent PTS in patients with a first proximal DVT, enrolled in 24 community and tertiary-care hospitals from 2004 to 2010. Multivariable logistic regression analysis of baseline characteristics was performed. The outcome was the occurrence of PTS, diagnosed starting from 6 months or later according to Ginsberg's criteria. Results Seven hundred and sixty-two patients were included in the analysis. The median follow-up was 728 days. The model includes three independent predictors, and has a range of possible scores from 0 to 5. High-risk predictors were: index DVT in the iliac vein; body mass index of ≥ 35 kg m-2 ; and moderate-severe Villalta severity category at DVT diagnosis. As compared with patients with a score of 0, those with a score of ≥ 4 had an odds ratio of 5.9 (95% confidence interval 2.1-16.6) for developing PTS. Conclusions To our knowledge, this is the first clinical prediction score for PTS. We identified three independent predictors that, when combined, predicted PTS risk after a first proximal DVT. The SOX-PTS score requires external validation before it can be considered for clinical use.

ABO blood group and the risk of post-thrombotic syndrome

Post-thrombotic syndrome (PTS) has been associated to DVT recurrence, increased FVIII, inflammatory biomarker plasma levels, and persistence of vein obstruction. These same features have also been widely reported in non-O blood type subjects. Our aim was to investigate the correlation between the incidence of PTS and ABO blood types. Consecutive patients referred to the Department of Medicine of University of Padua between January 2004 and January 2012 following the diagnosis of a first episode of proximal DVT were enrolled. The presence of PTS was assessed via the Villalta scale at predefined time points (3, 6, 12, 18, 24, 36 months). Hazard ratio (HR) for PTS development was calculated in non-O (exposed) vs O blood (unexposed) type patients. Out of 671 eligible patients, 606 were enrolled. Overall, 192 (31.7%) patients developed PTS: 142 (34.5%) non-O and 50 (25.6%) O blood type patients. Individuals with non-O blood group were associated with a significantly higher risk to develop PTS (HR 1.53, 95% CI, 1.05-2.24; p = 0.028) than O group. Non-O blood type might be a risk factor for the development of PTS.

Perivascular Perfusion on Contrast-Enhanced Ultrasound (CEUS) Is Associated with Inflammation in Patients with Acute Deep Vein Thrombosis

Background Inflammatory processes of the venous wall in acute deep vein thrombosis (DVT) play a role in thrombus formation and resolution. However, direct evaluation of the perivascular inflammation is currently not feasible. Objective To assess perivascular perfusion in acute proximal DVT using contrast-enhanced ultrasound (CEUS) reflecting perivenous inflammation and its association with systemic inflammatory markers in a single-centre, prospective observational study. Patients/Methods Twenty patients with proximal DVT underwent CEUS imaging in the thrombosed and contralateral popliteal vein at baseline and after 2 weeks and 3 months. Perfusion was quantified by measuring peak enhancement (PE) and wash-in rate (WiR) in a perivenous region after bolus injection of the contrast agent. High-sensitive C-reactive protein (hsCRP) and interleukin-6 (IL-6) were determined at the time of each CEUS imaging. Results PE and WiR were significantly higher in the thrombosed compared with the unaffected leg at baseline (1,007 vs. 34 au and 103 vs. 4 au/s) and 2-week follow-up (903 vs. 35 au and 70 vs. 4 au/s). Compared with baseline, PE and WiR in the thrombosed leg significantly decreased to 217 au and 18 au/s at 3-month follow-up.At baseline, hsCRP and IL-6 were elevated at 20.1 mg/mL and 8.2 pg/mL and decreased significantly to 2.8 mg/mL and 2.6 pg/mL at 2-week follow-up, remaining low after 3 months. There was a weak association between the level of inflammatory markers and the CEUS parameters at baseline on the thrombosed leg. Conclusion Elevated perivascular perfusion assessed by CEUS imaging is associated with the inflammatory response in acute DVT.

IQCA-TAVV: To explore the effect of P-selectin, GPIIb/IIIa, IL-2, IL-6 and IL-8 on deep venous thrombosis

Deep vein thrombosis (DVT) associates with considerable morbidity, functional disability and mortality. Due to the lack of suitable inhibitor the correlation of various factors in DVT onset remains unknown. In this context we analyzed the structure of anti-platelet aggregation agent, P-selectin down-regulator, GPIIb/IIIa down-regulator and anti-inflammatory agent, thereby designed N-(3S-1,2,3,4-tetrahydroisoquinoline-3-carbonyl)- Thr-Ala-Arg-Gly-Asp(Val)-Val (IQCA-TAVV) as an inhibitor of DVT to receive evaluations. The docking predicted that IQCA-TAVV can target P-selectin and GPIIb/IIIa. The UV showed that IQCA-TAVV can act on P-selectin and GPIIb/IIIa. ELISA indicated that IQCA-TAVV concentration dependently inhibited activated platelets to express P-selectin and GPIIb/IIIa, and the minimal effective concentration was 1 nM. IC50 of IQCA-TAVV against platelet aggregation induced by arachidonic acid, adenosine diphosphate and platelet activating factor fell within a range of 0.13 nM to 0.30 nM. In vivo IQCA-TAVV dose-dependently inhibited venous thrombosis and the minimal effective dose was 1 nmol/kg. On ear edema model the anti-inflammation activity of 10 nmol/kg IQCA-TAVV equaled that of 1.1mmol/kg aspirin. The concentration of IL-2, IL-6 and IL-8 in the serum of the ear edema mice were also significantly decreased by 10 nmol/kg IQCA-TAVV. Even at 1 μmol/kg of dose IQCA-TAVV still did not injure the kidney, the liver, and the nerves of healthy mice. Thereby IQCA-TAVV depicts a relationship of three levels (inhibiting platelet activation, targeting externalized membrane receptor, decreasing serum inflammatory factor) for the down-regulation of P-selectin, GPIIb/IIIa, IL-2, IL-6 and IL-8 in DVT.

Epidemiology of the post-thrombotic syndrome

The post thrombotic syndrome (PTS) refers to clinical manifestations of chronic venous insufficiency (CVI) following a deep-vein thrombosis (DVT). PTS is the most frequent complication of DVT, which develops in 20 to 50% of cases after proximal DVT and is severe in 5-10% of cases. The reported prevalence of PTS differs widely among studies because of differences in study populations, tools used to assess PTS, and time interval between acute DVT and PTS assessment. The two most important predictors of PTS are extensive proximal character of DVT and previous ipsilateral DVT. Other reported risk factors include pre-existing CVI, obesity, quality of anticoagulant treatment, older age and residual venous obstruction. Standardization of PTS assessment tools combined with the development of patient self-reported PTS scales are likely to constitute a breakthrough in research of the epidemiology of PTS, by allowing comparison between studies, meta-analyses and increasing the feasibility of longer follow-up of DVT patients. This should enable identification of patient populations at high risk of severe PTS, new predictors of PTS and targets for potential new treatments. In this perspective, identification of biomarkers that are predictive of PTS such as markers of inflammation is crucial in ongoing research.

Intermittent Pneumatic Compression for the Prevention of Venous Thromboembolism after Total Hip Arthroplasty

BACKGROUND

Venous thromboembolism (VTE) is a relatively common and potentially life threatening complication after major hip surgery. There are two main types of prophylaxis: chemical and mechanical. Chemical prophylaxis is very effective but causes bleeding complications in surgical wounds and remote organs. On the other hand, mechanical methods are free of hemorrhagic complications but are less effective. We hypothesized that mechanical prophylaxis is effective enough for Asians in whom VTE occurs less frequently. This study evaluated the effect of intermittent pneumatic compression (IPC) in the prevention of VTE after major hip surgery.

METHODS

Incidences of symptomatic VTE after primary total hip arthroplasty with and without application of IPC were compared. A total of 379 patients were included in the final analysis. The IPC group included 233 patients (106 men and 127 women) with a mean age of 54 years. The control group included 146 patients (80 men and 66 women) with a mean age of 53 years. All patients took low-dose aspirin for 6 weeks after surgery. IPC was applied to both legs just after surgery and maintained all day until discharge. When a symptom or a sign suspicious of VTE, such as swelling or redness of the foot and ankle, Homans' sign, and dyspnea was detected, computed tomography (CT) angiogram or duplex ultrasonogram was performed.

RESULTS

Until 3 months after surgery, symptomatic VTE occurred in three patients in the IPC group and in 6 patients in the control group. The incidence of VTE was much lower in the IPC group (1.3%) than in the control group (4.1%), but the difference was not statistically significant. Complications associated with the application of IPC were not detected in any patient. Patients affected by VTE were older and hospitalized longer than the unaffected patients.

CONCLUSIONS

The results of this study suggest that IPC might be an effective and safe method for the prevention of postoperative VTE.

The postthrombotic syndrome: current evidence and future challenges

Postthrombotic syndrome (PTS) is a chronic complication of deep vein thrombosis (DVT) that develops in 20-50% of patients. PTS manifests as a spectrum of symptoms and signs of chronic venous insufficiency that can impose significant morbidity and have a negative impact on quality of life. Chronic venous hypertension caused by a combination of residual venous obstruction and valvular reflux is believed to play a major role in the pathophysiology of PTS. The Villalta scale is the most widely applied clinical scale used to diagnose and define PTS. Proximal DVT and recurrent ipsilateral DVT are the two principal established risk factors for PTS, and efforts in recent years have been focused on identifying a combination of clinical and biomarker predictors that will define high-risk patients and possibly new therapeutic targets. The best way to prevent PTS is to prevent the occurrence of DVT, and to provide optimal anticoagulation for the acute phase of DVT once it occurs. Recent years have brought progress in our understanding of the role of endovascular techniques in the prevention and treatment of PTS and the subgroups of patients that may benefit from these modalities. Pharmacomechanical catheter-directed thrombolysis is the most promising interventional modality for prevention of PTS. This review summarizes the current state of evidence on PTS of the lower limbs, and highlights areas where uncertainty still exists that require further research.

ADAMTS13: more than a regulator of thrombosis

ADAMTS13, a plasma reprolysin-like metalloprotease, proteolyzes von Willebrand factor (VWF). ADAMTS13 is primarily synthesized by hepatic stellate cells (HSCs), and mainly regulates thrombogenesis by cleaving VWF. Recent studies demonstrate that ADAMTS13 also plays a role in the down-regulation of inflammation, regulation angiogenesis, and degradation of extracellular matrix. The purpose of this review is to introduce the state of progress with respect to some of the theorized roles of ADAMTS13.

Effects of IL-1β, IL-6 and IL-8 on erythrocytes, platelets and clot viscoelasticity

Complex interactions exist between cytokines, and the interleukin family plays a fundamental role in inflammation. Particularly circulating IL-1β, IL-6 and IL-8 are unregulated in systemic and chronic inflammatory conditions. Hypercoagulability is an important hallmark of inflammation, and these cytokines are critically involved in abnormal clot formation, erythrocyte pathology and platelet hyper-activation, and these three cytokines have known receptors on platelets. Although these cytokines are always unregulated in inflammation, we do not know how the individual cytokines act upon the structure of erythrocytes and platelets, and which of the viscoelastic clot parameters are changed. Here we study the effects of IL-1β, IL-6 and IL-8 at low physiological levels, representative of chronic inflammation, by using scanning electron microscopy and thromboelastography. All three interleukins caused the viscoelastic properties to display an increased hypercoagulability of whole blood and pathology of both erythrocytes and platelets. The most pronounced changes were noted where all three cytokines caused platelet hyper-activation and spreading. Erythrocyte structure was notably affected in the presence of IL-8, where the morphological changes resembled that typically seen in eryptosis (programmed cell death). We suggest that erythrocytes and platelets are particularly sensitive to cytokine presence, and that they are excellent health indicators.

An IRF5 Decoy Peptide Reduces Myocardial Inflammation and Fibrosis and Improves Endothelial Cell Function in Tight-Skin Mice

Interferon regulatory factor 5 (IRF5) has been called a "master switch" for its ability to determine whether cells mount proinflammatory or anti-inflammatory responses. Accordingly, IRF5 should be an attractive target for therapeutic drug development. Here we report on the development of a novel decoy peptide inhibitor of IRF5 that decreases myocardial inflammation and improves vascular endothelial cell (EC) function in tight-skin (Tsk/+) mice. Biolayer interferometry studies showed the Kd of IRF5D for recombinant IRF5 to be 3.72 ± 0.74x10-6M. Increasing concentrations of IRF5D (0-100 μg/mL, 24h) had no significant effect on EC proliferation or apoptosis. Treatment of Tsk/+ mice with IRF5D (1mg/kg/d subcutaneously, 21d) reduced IRF5 and ICAM-1 expression and monocyte/macrophage and neutrophil counts in Tsk/+ hearts compared to expression in hearts from PBS-treated Tsk/+ mice (p<0.05). EC-dependent vasodilatation of facialis arteries isolated from PBS-treated Tsk/+ mice was reduced (~15%). IRF5D treatments (1mg/kg/d, 21d) improved vasodilatation in arteries isolated from Tsk/+ mice nearly 3-fold (~45%, p<0.05), representing nearly 83% of the vasodilatation in arteries isolated from C57Bl/6J mice (~55%). IRF5D (50μg/mL, 24h) reduced nuclear translocation of IRF5 in myocytes cultured on both Tsk/+ cardiac matrix and C57Bl/6J cardiac matrix (p<0.05). These data suggest that IRF5 plays a causal role in inflammation, fibrosis and impaired vascular EC function in Tsk/+ mice and that treatment with IRF5D effectively counters IRF5-dependent mechanisms of inflammation and fibrosis in the myocardium in these mice.

Compression to prevent PTS: a controversy?

Compression therapy, prescribed as elastic compression stockings, is the cornerstone in the management of post-thrombotic syndrome. The effectiveness of elastic compression stockings has recently been called into question in a large randomized placebo-controlled trial. The findings however may be less contradictory than assumed and presented. The mechanistic substrate for the effectiveness of compression therapy is based on its ability to counteract venous hypertension, which is a central aspect in the pathophysiology of post-thrombotic syndrome. Nevertheless, despite elastic compression stockings a significant percentage (20–50%) of patients develops post-thrombotic syndrome, suggesting that there are other factors to be considered next to compression. Every patient has an individual baseline risk value, constituted of non-modifiable and modifiable risk factors (i.e. age, sex, bodyweight etcetera). Straining patients at risk is therefore crucial. Exploring additional or alternative forms of therapy is desirable as well since these are in addition to the risk factors, costs aspects and quality of life, puzzle pieces in the management of post-thrombotic syndrome, which once pieced together enables multifactorial yet individualized therapy.