Asthma is associated with enhanced thrombin formation and impaired fibrinolysis

Factor VIIa-Antithrombin Complexes are Increased in Asthma: Relation to the Exacerbation-Prone Asthma Phenotype

BACKGROUND

 Asthma is associated with a prothrombotic state. Plasma factor VIIa-antithrombin complex (FVIIa-AT) concentrations indirectly reflect the interaction of tissue factor (TF) with FVII. Since TF is a key initiator of coagulation in vivo, we hypothesized that FVIIa-AT concentrations are higher in asthma.

METHODS

 In 159 clinically stable adult asthma patients and 62 controls, we determined FVIIa-AT in plasma and analyzed their relation to circulating inflammatory and prothrombotic markers together with the total plasma potential for fibrinolysis (clot lysis time, CLT) and thrombin generation. We recorded clinical outcomes, including asthma exacerbations, during 3-year follow-up.

RESULTS

 Asthma patients were characterized by 38.5% higher FVIIa-AT (p < 0.001), related to bronchial obstruction (FEV1: r = -0.397, p < 0.001), asthma severity (r = 0.221, p = 0.005), and duration (r = 0.194, p = 0.015) compared to controls. FVIIa-AT showed weak positive associations with C-reactive protein (r = 0.208, p = 0.009), fibrinogen (r = 0.215, p = 0.007), and CLT (r = 0.303, p < 0.001) but not with thrombin generation parameters. In the follow-up (data obtained from 151 patients), we documented 151 severe asthma exacerbations in 51 (33.8%) patients, including 33 (21.9%) with ≥2 such events. Exacerbation-prone asthma phenotype was related to 13.1% higher FVIIa-AT (p = 0.012), along with asthma severity and control (p < 0.003, both). High FVIIa-AT (that is ≥100.1 pmol/L), defined on receiver operating characteristic curves, was linked to exacerbation-prone asthma phenotype (odds ratio 1.85; 95%CI: 1.23-2.80, p = 0.003) and shorter time to first exacerbation (p = 0.023).

CONCLUSION

 This study is the first to show that FVIIa-AT concentrations are higher in asthma in relation to its severity and may help identify individuals at risk of the exacerbation-prone asthma phenotype.

Association between asthma and cardiovascular disease: evidence from the national health and nutrition examination survey 1999-2018

Background

Cardiovascular disease(CVD) remains a significant global challenge. Asthma, which is characterized by airway hyperresponsiveness and reversible and limited airflow, plays an important role in cardiovascular diseases. This study aimed to investigate the association between asthma and CVD.

Methods

This cross-sectional study included demographic, laboratory, and questionnaire data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. CVD included stroke, congestive heart failure, coronary heart disease, and angina. Multiple logistic regression models were used to detect the association between asthma and the prevalence of CVD, adjusting for age, gender, race, education level, body mass index, ratio of family income to poverty, smoking exposure, drinking exposure, diabetes history, hypertension history, chronic obstructive pulmonary disease (COPD) history, and chronic kidney disease (CKD) history. A subgroup analysis was performed to investigate the association between asthma and CVD in different populations.

Results

In total, 16,807 participants were included in this study, including 2,446 who reported having asthma. Compared with participants without asthma, the prevalence of stroke in those with asthma was increased by 1.607 times; the prevalence of congestive heart failure was increased by 1.911 times. Asthma significantly increased the prevalence of stroke among participants aged 18-44 years old, with a BMI 18.50-29.99 kg/m2, with low education levels, and with a PIR < 1.00. Asthma also increased the prevalence of angina in females, non-Hispanic Blacks, participants aged 45-59 years old, with a BMI ≥ 30.00 kg/m2, and with a PIR < 1.00. The prevalence of congestive heart failure was positively associated with asthma in non-Hispanic Whites or Blacks, participants aged ≥45 years old, with a BMI 25.00-29.99 kg/m2, with a PIR < 1.00, and with a low or middle education level.

Conclusion

Asthma significantly increases the prevalence of stroke, congestive heart failure. Patients with asthma should be monitored for CVD, including stroke and congestive heart failure.

Association between asthma and cardiovascular diseases: A longitudinal follow-up study using a national health screening cohort

Background

Asthma has been suggested to be a risk factor for cardiovascular diseases (CVDs), although the evidence supporting this relationship is inconclusive. This study aimed to explore the long-term associations between asthma and asthma exacerbations with the occurrence of cardiovascular diseases (CVDs) such as ischemic heart disease (IHD), heart failure (HF), and cerebral stroke, utilizing data from a nationwide cohort.

Materials and methods

This study utilized data from the Korean National Health Insurance Service-Health Screening Cohort database (2002-2015), including information on 111,316 asthma patients and an equal number of 1:1 matched control participants. A propensity score overlap-weighted Cox proportional hazards regression model was used to analyze the overlap-weighted hazard ratios (HRs) of asthma and exacerbated asthma for cardiovascular diseases (CVDs) within this cohort.

Results

During the follow-up period, the incidence rate (IR) of IHD per 1000 person-years (PYs) was 7.82 in patients with asthma and 5.79 in controls. The IR of HF was 2.53 in asthmatic patients and 1.36 in controls. After adjustment for covariates, asthmatic patients exhibited 1.27-fold and 1.56-fold higher HRs for IHD (95% confidence interval (CI) = 1.23-1.37, P < 0.001) and HF (95% CI = 1.36-1.63, P < 0.001) than the controls, respectively. In addition, there was an increased HR for IHD and HF in the asthma exacerbation group compared with the nonexacerbated asthma group (adjusted HR, 1.29, 95% CI = 1.24-1.34, P < 0.001 for IHD and aHR 1.68, 95% CI = 1.58-1.79, P < 0.001 for HF). However, the occurrence of stroke was decreased in asthmatic patients compared with controls (aHR = 0.96, 95% CI = 0.93-0.99, P = 0.008).

Conclusions

Adults with asthma are more likely to develop CVDs. Additionally, severe asthma exacerbations are significantly associated with an increased occurrence of CVDs.

Thrombin-Induced COX-2 Expression and PGE2 Synthesis in Human Tracheal Smooth Muscle Cells: Role of PKCδ/Pyk2-Dependent AP-1 Pathway Modulation

In this study, we confirmed that thrombin significantly increases the production of COX-2 and PGE2 in human tracheal smooth muscle cells (HTSMCs), leading to inflammation in the airways and lungs. These molecules are well-known contributors to various inflammatory diseases. Here, we investigated in detail the involved signaling pathways using specific inhibitors and small interfering RNAs (siRNAs). Our results demonstrated that inhibitors targeting proteins such as protein kinase C (PKC)δ, proline-rich tyrosine kinase 2 (Pyk2), c-Src, epidermal growth factor receptor (EGFR), phosphatidylinositol 3-kinase (PI3K), or activator protein-1 (AP-1) effectively reduced thrombin-induced COX-2 and PGE2 production. Additionally, transfection with siRNAs against PKCδ, Pyk2, c-Src, EGFR, protein kinase B (Akt), or c-Jun mitigated these responses. Furthermore, our observations revealed that thrombin stimulated the phosphorylation of key components of the signaling cascade, including PKCδ, Pyk2, c-Src, EGFR, Akt, and c-Jun. Thrombin activated COX-2 promoter activity through AP-1 activation, a process that was disrupted by a point-mutated AP-1 site within the COX-2 promoter. Finally, resveratrol (one of the most researched natural polyphenols) was found to effectively inhibit thrombin-induced COX-2 expression and PGE2 release in HTSMCs through blocking the activation of Pyk2, c-Src, EGFR, Akt, and c-Jun. In summary, our findings demonstrate that thrombin-induced COX-2 and PGE2 generation involves a PKCδ/Pyk2/c-Src/EGFR/PI3K/Akt-dependent AP-1 activation pathway. This study also suggests the potential use of resveratrol as an intervention for managing airway inflammation.

Hidden Comorbidities in Asthma: A Perspective for a Personalized Approach

Bronchial asthma is the most frequent inflammatory non-communicable condition affecting the airways worldwide. It is commonly associated with concomitant conditions, which substantially contribute to its burden, whether they involve the lung or other districts. The present review aims at providing an overview of the recent acquisitions in terms of asthma concomitant systemic conditions, besides the commonly known respiratory comorbidities. The most recent research has highlighted a number of pathobiological interactions between asthma and other organs in the view of a shared immunological background underling different diseases. A bi-univocal relationship between asthma and common conditions, including cardiovascular, metabolic or neurodegenerative diseases, as well as rare disorders such as sickle cell disease, α1-Antitrypsin deficiency and immunologic conditions with hyper-eosinophilia, should be considered and explored, in terms of diagnostic work-up and long-term assessment of asthma patients. The relevance of that acquisition is of utmost importance in the management of asthma patients and paves the way to a new approach in the light of a personalized medicine perspective, besides targeted therapies.

Decreased protein C activity, lower ADAMTS13 antigen and free protein S levels accompanied by unchanged thrombin generation potential in hospitalized COVID-19 patients

INTRODUCTION

COVID-19 is associated with an increased thromboembolic risk. However, the mechanisms triggering clot formation in those patients remain unknown.

PATIENTS AND METHODS

In 118 adult Caucasian severe but non-critically ill COVID-19 patients (median age 58 years; 73 % men) and 46 controls, we analyzed in vitro plasma thrombin generation profile (calibrated automated thrombogram [CAT assay]) and investigated thrombophilia-related factors, such as protein C and antithrombin activity, free protein S level, presence of antiphospholipid antibodies and factor V Leiden R506Q and prothrombin G20210A mutations. We also measured circulating von Willebrand factor (vWF) antigen and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) antigen and activity. In patients, blood samples were collected on admission to the hospital before starting any therapy, including heparin. Finally, we examined the relationship between observed alterations and disease follow-up, such as thromboembolic complications.

RESULTS

COVID-19 patients showed 17 % lower protein C activity, 22 % decreased free protein S levels, and a higher prevalence of positive results for IgM anticardiolipin antibodies. They also had 151 % increased vWF, and 27 % decreased ADAMTS13 antigens compared with controls (p < 0.001, all). On the contrary, thrombin generation potential was similar to controls. In the follow-up, pulmonary embolism (PE) occurred in thirteen (11 %) patients. They were characterized by a 55 % elevated D-dimer (p = 0.04) and 2.7-fold higher troponin I (p = 0.002) during hospitalization and 29 % shorter time to thrombin peak in CAT assay (p = 0.009) compared to patients without PE.

CONCLUSIONS

In COVID-19, we documented prothrombotic abnormalities of peripheral blood. PE was characterized by more dynamic thrombin generation growth in CAT assay performed on admittance to the hospital.

Development of Adaptive Immunity and Its Role in Lung Remodeling

Asthma is characterized by airflow limitations resulting from bronchial closure, which can be either reversible or fixed due to changes in airway tissue composition and structure, also known as remodeling. Airway remodeling is defined as increased presence of mucins-producing epithelial cells, increased thickness of airway smooth muscle cells, angiogenesis, increased number and activation state of fibroblasts, and extracellular matrix (ECM) deposition. Airway inflammation is believed to be the main cause of the development of airway remodeling in asthma. In this chapter, we will review the development of the adaptive immune response and the impact of its mediators and cells on the elements defining airway remodeling in asthma.

Prothrombotic state, endothelial injury, and echocardiographic changes in non-active sarcoidosis patients

Sarcoidosis is a multisystem inflammatory granulomatous disease of unknown cause that most commonly affects lungs and lymph nodes, with frequent yet asymptomatic cardiac involvement. The epidemiologically associated cardiovascular risk suggests an underlying prothrombotic state and endothelial dysfunction, currently understudied in the available literature. Therefore, we aimed to investigate prothrombotic plasma properties together with selected echocardiographic and laboratory biomarkers of cardiovascular injury in that disease. N = 53 patients with pulmonary sarcoidosis in clinical remission and N = 66 matched controls were assessed for inflammatory and endothelial injury biomarkers, plasma thrombin generation profile, and echocardiographic and lung function parameters. Sarcoidosis cases had impaired systolic and diastolic left ventricular function, higher concentrations of inflammatory markers, D-dimer and factor VIII activity compared to the controls. The coexistence of extrapulmonary disease was associated with elevated circulating vascular cell adhesion molecule 1, while cases with hypercalcemia had higher thrombomodulin concentration. Sarcoidosis was characterized by the unfavorably altered thrombin generation profile, reflected by the 16% higher endogenous thrombin potential (ETP), 24% increased peak thrombin concentration, and 12% shorter time to thrombin peak in comparison to the control group. ETP was higher in cases with proxies of pulmonary restriction, extrapulmonary-extracutaneous manifestation, and need for corticosteroids use. Despite the clinical remission, sarcoidosis is related to prothrombotic plasma properties and signs of endothelial injury, likely contributing to the higher risk of cardiovascular events. In addition, subclinical cardiac involvement may play an additional role, although further clinical and experimental studies are needed to verify these findings.

Thrombin induces IL-8/CXCL8 expression by DCLK1-dependent RhoA and YAP activation in human lung epithelial cells

Background

Doublecortin-like kinase 1 (DCLK1) has been recognized as a marker of cancer stem cell in several malignancies. Thrombin is crucial in asthma severity as it can promote IL-8/CXCL8 production in lung epithelial cells, which is a potent chemoattractant for neutrophils. However, the pathologic role of DCLK1 in asthma and its involvement in thrombin-stimulated IL-8/CXCL8 expression remain unknown.

Methods

IL-8/CXCL8, thrombin, and DCLK1 expression were observed in the lung tissues of severe asthma patients and ovalbumin (OVA)-induced asthmatic mice model. A549 and BEAS-2B cells were either pretreated with inhibitors or small interfering RNAs (siRNAs) before being treated with thrombin. IL-8/CXCL8 expression and the molecules involved in signaling pathway were performed using ELISA, luciferase activity assay, Western blot, or ChIP assay.

Results

IL-8/CXCL8, thrombin, and DCLK1 were overexpressed in the lung tissues of severe asthma patients and ovalbumin (OVA)-induced asthmatic mice model. Our in vitro study found that DCLK siRNA or LRKK2-IN-1 (DCLK1 inhibitor) attenuated IL-8/CXCL8 release after thrombin induction in A549 and BEAS-2B cells. Thrombin activated DCLK1, RhoA, and YAP in a time-dependent manner, in which DCLK1 siRNA inhibited RhoA and YAP activation. YAP was dephosphorylated on the Ser127 site after thrombin stimulation, resulting in YAP translocation to the nucleus from the cytosol. DCLK1, RhoA and YAP activation following thrombin stimulation were inhibited by U0126 (ERK inhibitor). Moreover, DCLK1 and YAP siRNA inhibited κB-luciferase activity. Thrombin stimulated the recruitment of YAP and p65 to the NF-κB site of the IL-8/CXCL8 promoter and was inhibited by DCLK1 siRNA.

Conclusions

Thrombin activates the DCLK1/RhoA signaling pathway, which promotes YAP activation and translocation to the nucleus from the cytosol, resulting in YAP/p65 formation, and binding to the NF-κB site, which enhances IL-8/CXCL8 expression. DCLK1 might be essential in thrombin-stimulated IL-8/CXCL8 expression in asthmatic lungs and indicates a potential therapeutic strategy for severe asthma treatment.

Thrombin generation potential is increased in patients with autoimmune inflammatory myopathies

PURPOSE

Dermatomyositis and polymyositis (DM/PM) are rare autoimmune inflammatory myopathies, characterized by an increased risk of cardiovascular and thromboembolic events, likely related to the prothrombotic plasma properties. The aim of this study was to assess the in vitro thrombin generation profile as a biomarker of plasma procoagulant properties in DM/PM patients.

METHODS

In 58 clinically stable DM/PM patients and 67 controls matched for sex, age, body mass index, we measured plasma thrombin generation potential using the Calibrated Automated Thrombinography (CAT) and analyzed its relationship with clinical disease characteristics, including autoantibodies profile.

RESULTS

Patients with DM/PM had a 21% increase in endogenous thrombin potential (ETP), 36% higher peak thrombin concentration, and 11% faster thrombin generation, compared to controls (p ​< ​0.001, all, also after adjustment for potential confounders). Interestingly, although both diseases did not differ in thrombin generation potential, heterogenous variables predicted elevated ETPs in both of them. In DM, that was higher fibrinogen, C-reactive protein, and total cholesterol, whereas in PM, presence of arthritis and increased blood platelet count. Surprisingly, thrombin formation capacity remained in a robust inverse relationship with serum troponin (r ​= ​-0.67, p ​< ​0.001) in the patient group.

CONCLUSIONS

DM/PM patients are characterized by an increased thrombin generation potential, suggesting prothrombotic plasma properties in both diseases. However, more studies are needed to verify its rationale and role in DM/PM clinical course and unfavorable clinical outcomes.

Semi-automated thrombin dynamics applying the ST Genesia thrombin generation assay

Background

The haemostatic balance is an equilibrium of pro- and anticoagulant factors that work synergistically to prevent bleeding and thrombosis. As thrombin is the central enzyme in the coagulation pathway, it is desirable to measure thrombin generation (TG) in order to detect possible bleeding or thrombotic phenotypes, as well as to investigate the capacity of drugs affecting the formation of thrombin. By investigating the underlying processes of TG (i.e., prothrombin conversion and inactivation), additional information is collected about the dynamics of thrombin formation.

Objectives

To obtain reference values for thrombin dynamics (TD) analysis in 112 healthy donors using an automated system for TG.

Methods

TG was measured on the ST Genesia, fibrinogen on the Start, anti-thrombin (AT) on the STA R Max and α₂Macroglobulin (α₂M) with an in-house chromogenic assay.

Results

TG was measured using STG-BleedScreen, STG-ThromboScreen and STG-DrugScreen. The TG data was used as an input for TD analysis, in combination with plasma levels of AT, α₂M and fibrinogen that were 113% (108-118%), 2.6 μM (2.2 μM-3.1 μM) and 2.9 g/L (2.6-3.2 g/L), respectively. The maximum rate of the prothrombinase complex (PCmax) and the total amount of prothrombin converted (PCtot) increased with increasing tissue factor (TF) concentration. PC_tot increased from 902 to 988 nM, whereas PC_max increased from 172 to 508 nM/min. Thrombin (T)-AT and T-α₂M complexes also increased with increasing TF concentration (i.e., from 860 to 955 nM and from 28 to 33 nm, respectively). PC_tot, T-AT and T-α₂M complex formation were strongly inhibited by addition of thrombomodulin (-44%, -43%, and -48%, respectively), whereas PC_max was affected less (-24%). PC_tot, PC_max, T-AT, and T-α₂M were higher in women using oral contraceptives (OC) compared to men/women without OC, and inhibition by thrombomodulin was also significantly less in women on OC (p < 0.05).

Conclusions

TG measured on the ST Genesia can be used as an input for TD analysis. The data obtained can be used as reference values for future clinical studies as the balance between prothrombin conversion and thrombin inactivation has shown to be useful in several clinical settings.

Asthma can Promote Cardiomyocyte Mitophagy in a Rat Model

Clinical observations have shown the risk of cardiovascular disease during asthmatic changes. Whether and how asthma causes heart failure is the subject of debate. Here, we aimed to investigate the possibility of cardiomyocyte mitophagy in a rat model of asthma. Twelve mature Wistar rats were randomly allocated into the Control and Asthmatic rats (n = 6). To induce asthma, ovalbumin was injected intraperitoneally on days 1 and 8 and procedure followed by nebulization from days 14 to 32. After 2 weeks, we performed the pathological examination of both lungs and heart using Hematoxylin-Eosin staining. Real-time PCR analysis was used to measure the expression of mitophagic factors, such as Optineurin, Pink1, and mitofusin 1 and 2. Typical changes like increased inter-alveolar septa thickness and interstitial pneumonia were evident in asthmatic lungs. In cardiac tissue, slight inflammatory response, and hydropic degeneration with an eosinophilic appearance were detected in the cytoplasm of cardiomyocytes. Real-time PCR analysis showed mitophagic response in pulmonary and cardiac tissues via upregulation of mitophagy-related genes like Optineurin and Pink-1 in asthmatic lungs and hearts compared to the control group (p < 0.05). Likewise, asthmatic changes increased the expression of genes associated with mitochondrial fusion in the lungs and heart. The expression of mitofusin1 and 2 was significantly increased following inflammatory response in pulmonary and cardiac tissues (p < 0.05). Our findings showed the expression of certain factors related to mitophagy during chronic asthmatic conditions. The findings open a new avenue in the understanding of cardiomyocyte injury during asthma.

Increased Oxidative Stress in Asthma-Relation to Inflammatory Blood and Lung Biomarkers and Airway Remodeling Indices

Airway inflammation in asthma is related to increased reactive oxygen species generation, potentially leading to tissue injury and subsequent airway remodeling. We evaluated oxidative stress in peripheral blood from asthmatic subjects (n = 74) and matched controls (n = 65), using recently developed real-time monitoring of the protein hydroperoxide (HP) formation by the coumarin boronic acid (CBA) assay. We also investigated the relation of the systemic oxidative stress response in asthma to disease severity, lung function, airway remodeling indices (lung computed tomography and histology), and blood and bronchoalveolar lavage fluid (BAL) inflammatory biomarkers. We documented enhanced systemic oxidative stress in asthma, reflected by 35% faster and 58% higher cumulative fluorescent product generation in the CBA assay (p < 0.001 for both). The dynamics of HP generation correlated inversely with lung function but not with asthma severity or histological measures of airway remodeling. HP generation was associated positively with inflammatory indices in the blood (e.g., C-reactive protein) and BAL (e.g., interleukin [IL]-6, IL-12p70, and neutrophil count). Bronchial obstruction, thicker airway walls, increased BAL IL-6, and citrullinated histone 3 in systemic circulation independently determined increased HP formation. In conclusion, a real-time CBA assay showed increased systemic HP generation in asthma. In addition, it was associated with inflammatory biomarkers, suggesting that proper disease control can also lead to a decrease in oxidative stress.

Airway fibrin formation cascade in allergic asthma exacerbation: implications for inflammation and remodeling

BACKGROUND

Airway remodeling in patients with asthma, which leads to a decline in pulmonary function, is likely the result of repeated exacerbations often provoked by aeroallergen exposures. Aeroallegen exposure triggers a stereotypic response orchestrated by growth factor cytokines and other protein mediators. This results in a late-phase allergic reaction characterized by vascular permeability, recruitment of activated leukocytes, and activation of structural cells of the airway. The spectrum of protein mediators and their functions are incompletely understood.

METHODS

Bronchoalveolar lavage fluid (BALF) samples were obtained from 12 volunteers who exhibited robust eosinophilic recruitment following segmental bronchial provocation with allergen (SBP-Ag). We systematically identified and quantified proteins in BALF using high-performance liquid chromatography-high-resolution mass spectrometry (LC-MS/MS) followed by pathway analysis and correlations with airway physiology.

RESULTS

Pairwise analysis of protein abundance in BALF pre- vs post-SBP-Ag revealed that 55 proteins were upregulated and 103 proteins were downregulated. We observed enrichment of groups of proteins mapping to hemostasis/fibrin clot, platelet activation, lipoprotein assembly, neutrophil degranulation proteins, and acute-phase inflammation-airway remodeling pathways. The abundances of F2 and Fibrinogen γ (FGG) correlated with eosinophil numbers, whereas SERPINA3 negatively correlated with change in FeNO. The coagulation proteins F2 and KNG negatively correlated with FN1 an index of airway remodeling. Interestingly, patients with lower FEV1 showed distinct allergen-induced patterns of 8 BALF proteins, including MUC1, alarmins (HSPB1), and actin polymerization factors.

CONCLUSIONS

Protein abundance of the fibrin formation cascade, platelet activation and remodeling are associated with late-phase leukocyte numbers and markers of remodeling. Patients with lower FEV1 have distinct dynamic responses to allergen.

Allergic asthma is a risk factor for human cardiovascular diseases

Asthma is an allergic airway disease in which type 2-mediated inflammation has a pathogenic role. Cardiovascular diseases (CVDs) are type 1-dominant inflammatory diseases in which type 2 cytokines often have a protective role. However, clinical studies demonstrate that allergic asthma and associated allergies are essential risk factors for CVD, including coronary heart diseases, aortic diseases, peripheral arterial diseases, pulmonary embolism, right ventricular dysfunction, atrial fibrillation, cardiac hypertrophy and even hypertension. Mast cells, eosinophils, inflammatory cytokines and immunoglobulin (Ig)E accumulate in asthmatic lungs and in the injured heart and vasculature of patients with CVD. Clinical studies show that many anti-asthmatic therapies affect the risk of CVD. As such, allergic asthma and CVD may share common pathogenic mechanisms. Preclinical investigations indicate that anti-asthmatic drugs have therapeutic potential in certain CVDs. In this Review, we discuss how asthma and allied allergic conditions may contribute to the prevalence, incidence and progression of CVD and vice versa.

Thrombin Induces COX-2 and PGE2 Expression via PAR1/PKCalpha/MAPK-Dependent NF-kappaB Activation in Human Tracheal Smooth Muscle Cells

The inflammation of the airway and lung could be triggered by upregulation cyclooxygenase (COX)-2 and prostaglandin E₂ (PGE₂) induced by various proinflammatory factors. COX-2 induction by thrombin has been shown to play a vital role in various inflammatory diseases. However, in human tracheal smooth muscle cells (HTSMCs), how thrombin enhanced the levels of COX-2/PGE₂ is not completely characterized. Thus, in this study, the levels of COX-2 expression and PGE₂ synthesis induced by thrombin were determined by Western blot, promoter-reporter assay, real-time PCR, and ELISA kit. The various signaling components involved in the thrombin-mediated responses were differentiated by transfection with siRNAs and selective pharmacological inhibitors. The role of NF-κB was assessed by a chromatin immunoprecipitation (ChIP) assay, immunofluorescent staining, as well as Western blot. Our results verified that thrombin markedly triggered PGE₂ secretion via COX-2 upregulation which were diminished by the inhibitor of thrombin (PPACK), PAR1 (SCH79797), G_i/o protein (GPA2), G_q protein (GPA2A), PKCα (Gö6976), p38 MAPK (SB202190), JNK1/2 (SP600125), MEK1/2 (U0126), or NF-κB (helenalin) and transfection with siRNA of PAR1, G_qα, G_iα, PKCα, JNK2, p38, p42, or p65. Moreover, thrombin induced PAR1-dependent PKCα phosphorylation in HTSMCs. We also observed that thrombin induced p38 MAPK, JNK1/2, and p42/p44 MAPK activation through a PAR1/PKCα pathway. Thrombin promoted phosphorylation of NF-κB p65, leading to nuclear translocation and binding to the COX-2 promoter element to enhance promoter activity, which was reduced by Gö6976, SP600125, SB202190, or U0126. These findings supported that COX-2/PGE₂ expression triggered by thrombin was engaged in PAR1/G_q or G_i/o/PKCα/MAPK-dependent NF-κB activation in HTSMCs.

Emerging Roles of Platelets in Allergic Asthma

Allergic asthma is a complex chronic inflammatory disease of the airways, driven by Th2 immune responses and characterized by eosinophilic pulmonary inflammation, airway hyperresponsiveness, excessive mucus production, and airway remodeling. Overwhelming evidence from studies in animal models and allergic asthmatic patients suggests that platelets are aberrantly activated and recruited to the lungs. It has been established that platelets can interact with other immune cells and secrete various biochemical mediators to promote allergic sensitization and airway inflammatory response, and platelet deficiency may alleviate the pathological features and symptoms of allergic asthma. However, the comprehensive roles of platelets in allergic asthma have not been fully clarified, leaving attempts to treat allergic asthma with antiplatelet agents questionable. In this review, we summarize the role of platelet activation and pulmonary accumulation in allergic asthma; emphasis is placed on the different interactions between platelets with crucial immune cell types and the contribution of platelet-derived mediators in this context. Furthermore, clinical antiplatelet approaches to treat allergic asthma are discussed. This review provides a clearer understanding of the roles of platelets in the pathogenesis of allergic asthma and could be informative in the development of novel strategies for the treatment of allergic asthma.

Thrombin cleaves IL-33 and modulates IL-33-activated allergic lung inflammation

BACKGROUND

Organisms have orchestrated coagulation and immune systems. Although a link between inflammation and haemostasis has been reported in asthma, the interaction mechanism has not been completely elucidated. Here, we investigated the direct link between the mammalian immune and coagulation systems.

METHODS

Mice were administered protease or antigens intranasally to induce airway inflammation with or without thrombin inhibitors treatment. The effects of thrombin and its inhibitors on interleukin (IL)-33 were investigated both in vivo and in vitro. Peripheral blood mononuclear cells (PBMCs) and plasma from asthma patients are collected to verify the correlation between thrombin and group 2 innate lymphocytes (ILC2s).

RESULTS

Low-molecular-weight heparin (LMWH, an indirect inhibitor of thrombin) restrained both papain- and fungus-induced type 2 immune responses in mice by inhibiting IL-33 cleavage. Upon examining the potential thrombin protease consensus sites, we found that IL-33 was directly cleaved by thrombin at specific amino acids (R48 and R106) to generate a mature form of IL-33 with potent biological activity. In addition, we found that bivalirudin TFA (a direct inhibitor of thrombin) inhibited a variety of type 2 inflammatory responses, such as those in house dust mite (HDM)- and ovalbumin (OVA)-mediated pulmonary inflammation models. We found that plasma thrombin-antithrombin complex (TATc) levels in asthma patients were positively associated with the number and function of IL-33-responder group 2 innate lymphocytes (ILC2s) among peripheral blood mononuclear cells (PBMCs) from asthma patients.

CONCLUSION

The data suggested that thrombin inhibitors administration could be effective in treating lung inflammation by regulating ILC2s via IL-33 maturation, indicating that targeting thrombin is a potential way to treat allergic diseases.

The Utility and Potential of Mathematical Models in Predicting Fibrinolytic Outcomes

The enzymatic degradation of blood clots, fibrinolysis, is an important part of a healthy hemostatic system. If intrinsic fibrinolysis is ineffective, thrombolysis - the clinically-induced enzymatic degradation of blood clots - may be necessary to treat life-threatening conditions. In this review we discuss recent models of fibrinolysis and thrombolysis, and open questions that could be resolved through modeling and modeling-experimental collaboration. In particular, we focus on 2- and 3-dimensional models that can be used to study effects of fibrin network structure and realistic blood vessel geometries on the phenomena underlying lytic outcomes. Significant open questions such as the role of clot contraction, network and inherent fiber tension, and fibrinolytic inhibitors in lysis could benefit from mathematical models aimed at understanding the underlying biological mechanisms.

Dynamic Urinary Proteome Changes in Ovalbumin-Induced Asthma Mouse Model Using Data-Independent Acquisition Proteomics

Background

In this work, we aim to investigate dynamic urinary proteome changes during asthma development and to identify potential urinary protein biomarkers for the diagnosis of asthma.

Methods

An ovalbumin (OVA)-induced mouse model was used to mimic asthma. The urinary proteome from asthma and control mice was determined using data-independent acquisition combined with high-resolution tandem mass spectrometry.

Results

Overall, 331 proteins were identified, among which 53 were differentially expressed (26, 24, 14 and 20 on days 2, 8, 15 and 18, respectively; 1.5-fold change, adjust P<0.05). Gene Ontology annotation of the differential proteins showed that the acute-phase response, innate immune response, B cell receptor signaling pathway, and complement activation were significantly enriched. Protein–protein interaction network revealed that these differential proteins were partially biologically connected in OVA-induced asthma, as a group. On days 2 and 8, after two episodes of OVA sensitization, six differential proteins (CRAMP, ECP, HP, F2, AGP1, and CFB) were also reported to be closely associated with asthma. These proteins may hold the potential for the early screening of asthma. On days 15 and 18, after challenged with 1% OVA by inhalation, seven differential proteins (VDBP, HP, CTSE, PIGR, AAT, TRFE, and HPX) were also reported to be closely associated with asthma. Thus, these proteins hold the potential to be biomarkers for the diagnosis of asthma attack.

Conclusion

Our results indicate that the urinary proteome could reflect dynamic pathophysiological changes in asthma progression.

Imbalanced Coagulation in the Airway of Type-2 High Asthma with Comorbid Obesity

Asthma is a common, chronic airway inflammatory disease marked by airway hyperresponsiveness, inflammation, and remodeling. Asthma incidence has increased rapidly in the past few decades and recent multicenter analyses have revealed several unique asthma endotypes. Of these, type-2 high asthma with comorbid obesity presents a unique clinical challenge marked by increased resistance to standard therapies and exacerbated disease development. The extrinsic coagulation pathway plays a significant role in both type-2 high asthma and obesity. The type-2 high asthma airway is marked by increased procoagulant potential, which is readily activated following damage to airway tissue. In this review, we summarize the current understanding of the role the extrinsic coagulation pathway plays in the airway of type-2 high asthma with comorbid obesity. We propose that asthma control is worsened in obesity as a result of a systemic and local airway shift towards a procoagulant and anti-fibrinolytic environment. Lastly, we hypothesize bariatric surgery as a treatment for improved asthma management in type-2 high asthma with comorbid obesity, facilitated by normalization of systemic procoagulant and pro-inflammatory mediators. A better understanding of attenuated coagulation parameters in the airway following bariatric surgery will advance our knowledge of biomolecular pathways driving asthma pathobiology in patients with obesity.

Asthma and stroke: a narrative review

Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation, bronchial reversible obstruction and hyperresponsiveness to direct or indirect stimuli. It is a severe disease causing approximately half a million deaths every year and thus possessing a significant public health burden. Stroke is the second leading cause of death and a major cause of disability worldwide. Asthma and asthma medications may be a risk factors for developing stroke. Nevertheless, since asthma is associated with a variety of comorbidities, such as cardiovascular, metabolic and respiratory, the increased incidence of stroke in asthma patients may be due to a confounding effect. The purpose of this review is to analyze the complex relationship between asthma and stroke.

Deciphering the coagulation profile through the dynamics of thrombin activity

Thrombosis has proven to be extremely difficult to predict. Measuring the generation of thrombin is a very sensitive method to detect changes in the hemostatic system. We developed a method based on the generation of thrombin to further fingerprint hemostasis, which we have named thrombin dynamics. Via this method we are able to exactly measure the prothrombin conversion and thrombin inactivation, and any change in the coagulation cascade will be reflected in these two processes. In the current study we analyzed the importance of the members of the prothrombin complex on the dynamics of thrombin activation and inactivation. We show that prothrombin conversion is predominantly influenced by factor X and antithrombin, which will provide essential insights in complex thrombosis-related diseases, such as liver cirrhosis and kidney failure.

Citrullinated histone H3, a marker of extracellular trap formation, is increased in blood of stable asthma patients

BACKGROUND

Emerging data indicates that extracellular traps (ETs), structures formed by various immune cell types, may contribute to the pathology of noninfectious inflammatory diseases. Histone hypercitrullination is an important step in ETs formation and citrullinated histone H3 (H3cit) is considered a novel and specific biomarker of that process. In the present study we have evaluated circulating H3cit in stable asthmatics and investigated its relationship with asthma severity, pulmonary function and selected blood and bronchoalveolar lavage (BAL) biomarkers.

METHODS

In 60 white adult stable asthmatics and 50 well-matched controls we measured serum levels of H3cit. In asthmatics we also performed bronchoscopy with BAL. We analyzed blood and BAL biomarkers, including interleukin (IL)-4, IL-5, IL-6, IL-10, IL-12p70, IL-17A and interferon γ. For statistical analysis, Mann-Whitney U-test, χ2 test, one-way ANCOVA, ROC curve analysis and univariate linear regression were applied. Independent determinants of H3cit were established in a multiple linear regression model.

RESULTS

Asthma was characterized by elevated circulating H3cit (17.49 [11.25-22.58] vs. 13.66 [8.66-18.87] ng/ml, p = 0.03). In asthmatics positive associations were demonstrated between serum H3cit and lung function variables, including total lung capacity (TLC) (β = 0.37 [95% CI 0.24-0.50]) and residual volume (β = 0.38 [95% CI 0.25-0.51]). H3cit was increased in asthma patients receiving systemic steroids (p = 0.02), as well as in subjects with BAL eosinophilia above 144 cells/ml (p = 0.02). In asthmatics, but not in controls, circulating H3cit correlated well with number of neutrophils (β = 0.31 [95% CI 0.19-0.44]) and monocytes (β = 0.42 [95% CI 0.29-0.55]) in peripheral blood. Furthermore, BAL macrophages, BAL neutrophils, TLC, high-sensitivity C-reactive protein, Il-12p70 and bronchial obstruction degree were independent determinants of H3cit in a multivariate linear regression model.

CONCLUSIONS

Asthma is characterized by increased circulating H3cit likely related to the enhanced lung ETs formation. Inhibition of ETs might be a therapeutic option in selected asthma phenotypes, such as neutrophilic asthma.

Out-Smarting the Host: Bacteria Maneuvering the Immune Response to Favor Their Survival

Bacteria adapt themselves to various environmental conditions in nature, which can lead to bacterial adaptation and persistence in the host as commensals or pathogens. In healthy individuals, host defense mechanisms prevent the opportunistic bacteria/commensals from becoming a pathological infection. However, certain pathological conditions can impair normal defense barriers leading to bacterial survival and persistence. Under pathological conditions such as chronic lung inflammation, bacteria employ various mechanisms from structural changes to protease secretion to manipulate and evade the host immune response and create a niche permitting commensal bacteria to thrive into infections. Therefore, understanding the mechanisms by which pathogenic bacteria survive in the host tissues and organs may offer new strategies to overcome persistent bacterial infections. In this review, we will discuss and highlight the complex interactions between airway pathogenic bacteria and immune responses in several major chronic inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD).

A prothrombotic state and denser clot formation in patients following acute limb ischemia of unknown cause

INTRODUCTION

Fibrin clot structure differs between healthy individuals and those following thromboembolic events. Dense and poorly lysable fibrin clots have also been reported in peripheral artery disease. We studied fibrin clot properties and its determinants in individuals with a history of acute lower limb ischemia (ALI) of unknown cause.

MATERIALS AND METHODS

In this case-control study, we enrolled 43 patients who experienced ALI of unknown cause, and two age-and sex-matched reference groups: (1) patients with cryptogenic non-lacunar stroke (n = 43) and (2) individuals without any history of thromboembolism (n = 43, control group). Plasma fibrin clot properties, along with thrombin generation and fibrinolysis markers were assessed following ≥3 months of anticoagulation.

RESULTS

Compared with the control group, the ALI group exhibited more compact plasma fibrin clots (13.4% lower permeability [K_s], p = .001), decreased formed clot lysis (12.5% lower D-D_rate, p = .001) and unaltered clot lysis potential, along with enhanced thrombin generation potential (49% higher peak thrombin concentration, p < .0001). There were no differences in these variables between ALI and stroke patients. Patients with ALI had slightly higher α₂-antiplasmin and lower plasminogen activator inhibitor 1 levels compared with the stroke and control groups (all p < .01).

CONCLUSIONS

Patients who experienced ALI of unknown cause display a prothrombotic fibrin clot phenotype, including increased clot density and hypofibrinolysis associated with higher thrombin generation, which might suggest potential benefits from prolonged anticoagulation in this disease.

Misunderstandings Between Platelets and Neutrophils Build in Chronic Inflammation

Regulated hemostasis, inflammation and innate immunity entail extensive interactions between platelets and neutrophils. Under physiological conditions, vascular inflammation offers a template for the establishment of effective intravascular immunity, with platelets providing neutrophils with an array of signals that increase their activation threshold, thus limiting collateral damage to tissues and promoting termination of the inflammatory response. By contrast, persistent systemic inflammation as observed in immune-mediated diseases, such as systemic vasculitides, systemic sclerosis, systemic lupus erythematosus or rheumatoid arthritis is characterized by platelet and neutrophil reciprocal activation, which ultimately culminates in the generation of thrombo-inflammatory lesions, fostering vascular injury and organ damage. Here, we discuss recent evidence regarding the multifaceted aspects of platelet-neutrophil interactions from bone marrow precursors to shed microparticles. Moreover, we analyse shared and disease-specific events due to an aberrant deployment of these interactions in human diseases. To restore communications between the pillars of the immune-hemostatic continuum constitutes a fascinating challenge for the near future.

The relationship of airway structural changes to blood and bronchoalveolar lavage biomarkers, and lung function abnormalities in asthma

BACKGROUND

Airway structural changes are important in asthma pathology and require further investigations.

OBJECTIVE

We sought to evaluate which computed tomography (CT) indices, bronchial histological traits, or blood and bronchoalveolar lavage (BAL) biomarkers correlate best with lung function abnormalities in asthma.

METHODS

In 105 white adult asthmatics (53 with a component of fixed airflow obstruction), we determined airway cross-sectional geometry of two proximal (the right upper lobe apical segmental and the left apicoposterior) and two distal (the right and the left basal posterior) bronchi, quantified the low-attenuation lung area (LAA%), and analysed clusters based on airway CT-metrics. We also performed bronchofiberoscopy with BAL and endobronchial biopsy, assessed blood and BAL biomarkers, including interleukin (IL)-4, IL-5, IL-6, IL-10, IL-12p70, IL-17A, IL-23, interferon (INF)γ and periostin, together with circulating a disintegrin and metalloproteinase domain-containing protein (ADAM)33, and investigated interplays between analysed variables.

RESULTS

Patients with fixed airflow limitation were characterized by lower lumen area and increased wall area and wall thickness ratios in distal airways, accompanied by raised LAA%. They had also higher blood neutrophilia, blood and BAL eosinophilia, increased circulating fibrinogen, periostin, and ADAM33. Blood neutrophilia, serum high density lipoproteins, thyroid-stimulating hormone, and shortened activated partial thromboplastin time were determinants of thicker reticular basement membrane (RBM). BAL eosinophilia was the only positive predictor of collagen I accumulation. Surprisingly, we observed a negative correlation between RBM thickening and collagen I deposit. Cluster analysis based on CT-metrics of the right lower lobe basal posterior bronchus revealed three well-separated clusters similar in age, asthma duration, and BMI, but different in RBM thickness, collagen I accumulation, and inflammatory markers.

CONCLUSIONS AND CLINICAL RELEVANCE

Airway remodelling traits are mainly related to the Th₂ profile, higher circulating ADAM33, and blood neutrophilia. Lung function abnormalities and RBM thickening correlate better with CT-metrics of distal than proximal airways.

Increased activity of lipoprotein-associated phospholipase A2 in non-severe asthma

BACKGROUND

Given increased risk of cardiovascular events in asthma we hypothesized that lipoprotein-associated phospholipase A₂ (Lp-PLA₂), an enzyme involved in atherosclerosis, is associated with proinflammatory and prothrombotic blood alterations in this disease.

METHODS

In 164 adult asthmatics (63 with severe asthma) we measured plasma Lp-PLA₂ activity using the PLAC test. We determined its relations to inflammation and prothrombotic blood alterations.

RESULTS

In asthma, Lp-PLA₂ was inversely related to the age (β = -0.1 [-0.18 to -0.02]) and was lower in women (n = 122 [74%], 205 [182-242] vs. 243 [203-262] nmol/min/ml, p = 0.001). Interestingly, Lp-PLA₂ correlated negatively with the asthma severity score (β = -0.15 [-0.23 to -0.07]), being 10.3% higher in those with non-severe (mild or moderate) asthma (n = 101, 62%) as compared to the severe disease subtype (224 [191-261] vs. 203 [181-229], p = 0.006 after adjustment for potential confounders). Lp-PLA₂ activity was positively related to the levels of low-density lipoprotein (β = 0.1 [0.02-0.18]), triglycerides (β = 0.11 [0.03-0.19]) and glucose (β = 0.1 [0.02-0.18]) and inversely to the tumor necrosis factor α (β = -0.27 [-0.35 to -0.2]), high sensitivity C-reactive protein (β = -0.1 [-0.19 to -0.02]) and fibrinogen (β = -0.12 [-0.21 to -0.03]), as well as prothrombin (β = -0.16 [-0.24 to -0.08]), and parameters describing thrombin generation potential, such as endogenous thrombin potential (β = -0.14 [-0.21 to -0.06]) and peak thrombin generated (β = -0.2 [-0.28 to -0.12]).

CONCLUSIONS

Elevated Lp-PLA₂ activity in non-severe asthmatics suggests increased atherosclerotic risk in this group. Lower Lp-PLA₂ activity accompanied by its inverse relationship to inflammatory or prothrombotic blood biomarkers observed in turn in severe asthmatics might be related to the pathogenesis of more severe asthma phenotype.

Ozbek O. Thrombin lag time is increased in children with mild asthma

BACKGROUND

Inflammation and coagulation are closely linked events. Thrombin is the key enzyme in coagulation system and also has roles in inflammation.

OBJECTIVE

The aim of our study was to evaluate thrombin generation in children with mild asthma.

METHODS

Forty-two children with mild asthma and 49 healthy children were included in the study. All patients performed spirometry. Thrombin generation tests (TGT) were performed with a calibrated automated thrombogram (CAT) in children without asthma exacerbation during the last six months. During CAT assay thrombogram curves were obtained. The area under the curve showed endogenous thrombin potentials and indicated the total amount of endogenous thrombin generated; the peak height showed the highest thrombin value, thrombin lag time and time to thrombin peak were measured.

RESULTS

Thrombin lag time was significantly longer in children with asthma (3.98±1.2min) compared to those in the control group (3.29±0.6min) (p<0.01). Children with asthma also had longer thrombin tail time compared to the control group (19.5±8.9min vs. 16.7±2.9min, p=0.02). Thrombin peak was inversely correlated with FEF 25-75 (r=-0.41, p<0.01). Thrombin lag time was inversely correlated with FEF 25-75 (r=-0.39, p<0.01).

CONCLUSION

Inflammation in mild asthma seems to disturb coagulation but this disturbance may not be so strong as to increase thrombin levels and may only affect the initiation phase of thrombin generation.

A Prothrombotic State in Patients With a History of Left Ventricular Thrombus

Left ventricular thrombus (LVT) is associated with a hypercoagulable state and occurs most frequently after myocardial infarction (MI). Blood prothrombotic alterations might predispose to LVT formation, its recurrence, and subsequent cerebrovascular events. We investigated 58 patients with a history of LVT unrelated to recent MI or LV ejection fraction <25% and 58 well-matched control subjects. We determined plasma clot permeability, fibrinolytic efficiency, thrombin generation, and endothelial markers after 3 to 6 months of anticoagulant treatment. During follow-up we recorded LVT and thromboembolic events. Patients with LVT more often had LV akinesia, congestive heart failure, and prothrombotic state as evidenced by increased endogenous thrombin potential, lower antithrombin, lower clot permeability, and longer clot lysis time associated with lower antiplasmin, higher plasminogen activator inhibitor-1, thrombin activatable fibrinolysis inhibitor, and von Willebrand factor. During follow-up (57.5 ± 8.1 months for LVT patients and 59.6 ± 5.3 months for controls) strokes, transient ischemic attacks, or LVT occurred in 18 (31%) LVT patients and in 6 (10.3%) control subjects (4.1 vs 1.4% per year, p = 0.006). LVT recurred in 10 (2.3%/year) patients, who had higher risk of stroke/transient ischemic attacks (relative risk = 4.73, 95% confidence interval 1.8 to 40.4). The most compact clot formation at baseline, defined as the lowest quartile of clot permeability (≤5.4 × 10^-9 cm²) was a predictor of recurrent LVT (relative risk = 4.67, 95% confidence interval 1.32 to 18.37). This study shows that a persistent prothrombotic state involving enhanced thrombin generation, hypofibrinolysis, and formation of more compact fibrin clots characterizes patients who develop LVT not related to MI and those prone to its recurrence.

Decreased Levels of Histidine-Rich Glycoprotein in Advanced Lung Cancer: Association with Prothrombotic Alterations

Background

Histidine-rich glycoprotein (HRG) displays anticoagulant and antifibrinolytic properties in animal models, but its effects in humans are unclear. We investigated serum HRG levels and their associations with the disease stage and prothrombotic alterations in lung cancer (LC) patients.

Methods

In 148 patients with advanced LC prior to anticancer therapy (87 non-small-cell LC and 61 small-cell LC) versus 100 well-matched controls, we measured HRG levels in association with clot permeability (K_s), clot turbidimetry (lag phase and maximum absorbance), and clot lysis time (CLT).

Results

Compared to controls, LC patients had 45.9% lower HRG levels with no associations with demographics and comorbidities. Decreased HRG, defined as the 90^th percentile of control values (<52.7 μg/ml), was 16 times more common in subjects with than without LC (OR = 16.4, 95% CI 9.2-23.5, p < 0.01). HRG < 38 μg/ml discriminated stage IIIAB/limited disease from IV/extensive disease (ED) LC. In LC patients, HRG correlated inversely with CLT (r = −0.41, p < 0.001), but not with other fibrin variables. Among stage IV/ED LC, HRG correlated significantly with K_s and lag phase (r = 0.28 and r = 0.33, respectively, both p < 0.001). LC patients with low K_s (10^th percentile of control values) combined with prolonged CLT (90^th percentile of control values) had reduced HRG levels compared to the remainder (p = 0.003). No such observations were noted in controls.

Conclusions

Our study is the first to show that decreased HRG levels occur in advanced LC and are associated with the disease stage and hypofibrinolysis.

Coagulopathies and inflammatory diseases: '…glimpse of a Snark'

Coagulopathies and inflammatory diseases, ostensibly, have distinct underlying molecular bases. Notwithstanding, both are host defense mechanisms to physical injury. In invertebrates, clotting can function directly in anti-pathogen defense. Molecules of the vertebrate clotting cascade have also been directly linked to the regulation of inflammation. We posit that thrombophilia may provide resistance against pathogens in vertebrates. The selective pressure of improved anti-pathogen defense may have retained mutations associated with a thrombophilic state in the human population and directly contributed to enhanced inflammation. Indeed, in some inflammatory diseases, at least a subset of patients can be identified as hypercoagulable. Therefore, anticoagulants such as warfarin or apixaban may have a therapeutic role in some inflammatory diseases.

Increased blood levels of cellular fibronectin in asthma: Relation to the asthma severity, inflammation, and prothrombotic blood alterations

BACKGROUND

Recently, we have reported that asthma is characterized by prothrombotic blood alterations, which were related to the low-grade inflammatory state. Inflammation, however, may also lead to vascular dysfunction. The aim of this study was to evaluate plasma levels of cellular fibronectin (cFN), a marker of vascular injury in asthmatics, and to analyze their impact on described previously prothrombotic blood alterations.

METHODS

In a cross-sectional study, we investigated 164 adult stable asthmatics and 72 matched controls. Plasma cFN was measured using an ELISA. Its relations to inflammation, thrombin generation, fibrinolytic capacity, expressed as clot lysis time (CLT), and platelet markers were evaluated.

RESULTS

Asthma was associated with 50.1% higher plasma cFN levels as compared with controls (p < 0.001, after adjustment for potential confounders). There was a positive association of cFN with asthma severity and inverse with the FEV₁/VC index (β = 0.2 [95%CI:0.13-0.28] and β = -0.15 [95%CI: -0.23 to -0.07], respectively). In asthmatics cFN positively correlated with high-sensitivity C-reactive protein (β = 0.24 [95%CI:0.16-0.32]), fibrinogen (β = 0.13 [95%CI:0.04-0.21]), interleukin-6 (β = 0.23 [95%CI:0.15-0.3]), platelet factor 4 (β = 0.14 [95%CI:0.06-0.21]), plasminogen (β = 0.11 [95%CI:0.04-0.19]) and CLT (β = 0.35 [95%CI:0.28-0.42]). In both groups cFN was related to the endogenous thrombin potential (ETP) (β = 0.51 [95%CI:0.44-0.57], and β = 0.17 [95%CI:0.07-0.27], respectively). Multiple regression models showed that cFN was the most potent independent predictor of both ETP and CLT in asthmatics.

CONCLUSION

Presented study is the first to show increased plasma cellular fibronectin in asthma, which is associated with disease severity, inflammation, and prothrombotic blood alterations. This novel observation suggests a previously unknown modulator of prothrombotic plasma properties in asthmatics.

Prothrombotic State in Asthma Is Related to Increased Levels of Inflammatory Cytokines, IL-6 and TNFα, in Peripheral Blood

Recently, we have reported that asthma is associated with enhanced plasma thrombin formation and impaired fibrinolysis. The mechanisms underlying the prothrombotic state in this disease are unknown. Our aim was to investigate whether prothrombotic alterations in asthmatics are associated with inflammation. We studied 164 adult, white, stable asthmatics and 72 controls matched for age, sex, body mass index (BMI), and smoking. Plasma tumor necrosis factor α (TNFα), interleukin (IL)-6, and serum periostin were evaluated using ELISAs, and their associations with thrombin generation, fibrinolytic capacity, expressed as clot lysis time (CLT), and platelet markers were later analyzed. Asthma was characterized by 62% higher plasma IL-6 and 35% higher TNFα (both, p < 0.0001). Inflammatory cytokines were higher in sporadic and persistent asthmatics compared to controls, also after adjustment for potential confounders. IL-6 was inversely related to the forced expiratory volume in 1 s/vital capacity (FEV₁/VC) spirometry index after correction for age, sex, and BMI. IL-6 and TNFα were associated with C-reactive protein in asthmatics (β = 0.6 [95% CI, 0.54–0.67] and β = 0.33 [95% CI, 0.25–0.41], respectively) and controls (β = 0.43 [95% CI, 0.29–0.57] and β = 0.33 [95% CI, 0.18–0.48], respectively). In asthma, IL-6 and TNFα positively correlated with the endogenous thrombin potential (β = 0.35 [95% CI, 0.28–0.42] and β = 0.15 [95% CI, 0.07–0.23], respectively) but not with CLT or platelet markers. However, TNFα predicted CLT in a multiple linear regression model. Periostin was not associated with any hemostatic parameters. Enhanced thrombin generation is driven in asthma by a systemic inflammatory state mediated by IL-6 and to a lesser extent TNFα, however, not periostin. TNFα might contribute to impaired fibrinolysis.

Toll-Like Receptor 7/8 Ligand, S28463, Suppresses Ascaris suum-induced Allergic Asthma in Nonhuman Primates

S28463 (S28), a ligand for Toll-like receptor 7/8, has been shown to have antiinflammatory properties in rodent models of allergic asthma. The principle goal of this study was to assess whether these antiinflammatory effects can also be observed in a nonhuman primate (NHP) model of allergic asthma. NHPs were sensitized then challenged with natural allergen, Ascaris suum extract. The animals were treated with S28 orally before each allergen challenge. The protective effect of S28 in NHPs was assessed by measuring various asthma-related phenotypes. We also characterized the metabolomic and proteomic signatures of the lung environment and plasma to identify markers associated with the disease and treatment. Our data demonstrate that clinically relevant parameters, such as wheal and flare response, blood IgE levels, recruitment of white blood cells to the bronchoalveolar space, and lung responsiveness, are decreased in the S28-treated allergic NHPs compared with nontreated allergic NHPs. Furthermore, we also identified markers that can distinguish allergic from nonallergic or allergic and drug-treated NHPs, such as metabolites, phosphocreatine and glutathione, in the plasma and BAL fluid, respectively; and inflammatory cytokines, IL-5 and IL-13, in the bronchoalveolar lavage fluid. Our preclinical study demonstrates that S28 has potential as a treatment for allergic asthma in primate species closely related to humans. Combined with our previous findings, we demonstrate that S28 is effective in different models of asthma and in different species, and has the antiinflammatory properties clinically relevant for the treatment of allergic asthma.

Contraction-dependent TGF-β1 activation is required for thrombin-induced remodeling in human airway smooth muscle cells

AIMS

Thrombin is a serine proteinase that is not only involved in coagulation cascade, but also mediates a number of biological responses relevant to tissues repair, and induces bronchoconstriction. TGF-β plays a pivotal role in airway remodeling due to its effects on airway smooth muscle proliferation and extracellular matrix (ECM) deposition. Recently, bronchoconstriction itself is found to constitute a form of strain and is highly relevant to asthmatic airway remodeling. However, the underlying mechanisms remain unknown. Here, we investigated the role of contraction- dependent TGF-β activation in thrombin-induced remodeling in human airway smooth muscle (HASM) cells.

MATERIALS AND METHODS

Primary HASM cells were treated with or without thrombin in the absence or presence of anti-TGF-β antibody, cytochalasin D and formoterol. CFSE labeling index or CCK-8 assay were performed to test cell proliferation. RT-PCR and Western blotting were used to examined ECM mRNA level and collagen Iα1, α-actin protein expression, respectively. Immunofluorescence was also used to confirm contraction induced by thrombin in HASM cells.

KEY FINDING

Thrombin stimulation enhanced HASM cells proliferation and activated TGF-β signaling. Thrombin induced ECM mRNA and collagen Iα1 protein expression, and these effects are mediated by TGF-β. Abrogation of TGF-β activation by contraction inhibitors cytochalasin D and formoterol prevents the thrombin-induced effects.

SIGNIFICANCE

These findings suggest that contraction-dependent TGF-β activation could be a mechanism by which thrombin leads to the development of asthmatic airway remodeling. Blocking physical forces with bronchodilator would be an intriguing way in reducing airway remodeling in asthma.

Pregnancy outcomes among women with asthma

PURPOSE

The purpose of this study is to examine the association between maternal asthma and pregnancy, delivery and neonatal outcomes.

MATERIALS AND METHODS

We carried out a retrospective cohort study using the Health Care Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) database from 2003 to 2011. Among women who delivered during this time period, we compared pregnancy, delivery, and neonatal outcomes in asthmatics versus non-asthmatics. Multivariate logistic regression was used to estimate adjusted odds ratios and 95% confidence intervals.

RESULTS

In a cohort of 7,772,999 pregnant women, 223,236 (2.9%) had asthma. The prevalence of asthma-complicated pregnancies rose over the study period from 1.9% in 2003 to 3.7% in 2011 (p < .001). Pregnant asthmatics had more pre-existing health conditions, such as diabetes, chronic hypertension, obesity, and thyroid disease, and were more likely to smoke. Even after adjustment for these comorbidities, and other covariates, within statistical models, asthma was found to be associated with greater risk of several pregnancy complications: gestational hypertension, preeclampsia, gestational diabetes, placenta previa, preterm premature rupture of membranes, placental abruption, chorioamnionitis, preterm delivery, postpartum hemorrhage, venous thromboembolism, caesarean section delivery, and maternal mortality. Neonates born to asthmatics had greater risk of being small for gestational age and for having congenital anomalies, and lower risk of intrauterine fetal death.

CONCLUSIONS

Asthma is associated with an increase in adverse pregnancy, labor, and neonatal outcomes. Close surveillance of asthmatic patients during the prenatal period is warranted and care in a tertiary hospital is advised.

Impaired fibrinolysis and lower levels of plasma α2-macroglobulin are associated with an increased risk of severe asthma exacerbations

Recently we have reported that asthma is associated with enhanced plasma thrombin formation, impaired fibrinolysis and platelet activation. In the present study we investigated whether described prothrombotic blood alterations might predispose to thromboembolic events or asthma exacerbations. In 164 adult asthmatics we assessed clinical events during 3-year follow-up and analyzed their associations with measured at baseline prothrombotic blood parameters. Data were obtained from 157 (95.7%) of the asthma patients. We documented 198 severe asthma exacerbations (64/year), which occurred in 53 subjects (34%). These patients were older (p = 0.004), had worse asthma control (p = 0.02) and lower spirometry values (p = 0.01), at baseline. Interestingly, this subgroup had longer clot lysis time (CLT), as well as lower α₂-macroglobulin (p = 0.038 and p = 0.04, respectively, after adjustment for potential confounders). Increased CLT and lower α₂-macroglobulin were demonstrated as independent predictors of asthma exacerbation in multiple regression model. Moreover, we documented two episodes of deep vein thrombosis (1.3%), and eight acute coronary syndromes (5.1%). Patients who experienced thromboembolic events (n = 10, 6.4%, 2.1%/year) had lower α₂-macroglobulin (p = 0.04), without differences in efficiency of fibrinolysis and thrombin generation. Impaired fibrinolysis and lower levels of α₂-macroglobulin might predispose to a higher rate of asthma exacerbations, suggesting new links between disturbed hemostasis and asthma.

Risk of pulmonary embolism and deep venous thrombosis in patients with asthma: a nationwide case-control study from Sweden

Asthma is associated with an increased risk of pulmonary embolism (PE) but little is known about whether asthma is associated with an increased risk of deep venous thrombosis (DVT). The aim in this study was to determine the risk of the first event of PE, DVT or a combination of PE and DVT in patients with asthma.We conducted this nationwide case-control study using data from Swedish nationwide registries. We included 114 366 Swedish-born patients with a first hospital diagnosis of PE, 76 494 patients with DVT and 6854 patients with both PE and DVT in Sweden between 1981 and 2010. We also included five age-, sex- and education-matched population controls. All previous hospital diagnoses of asthma were identified. Conditional logistic regression was used to compute odds ratios with adjustment for potential confounders.Asthma was associated with an adjusted odds ratio for PE of 1.43 (95% CI 1.37-1.50), for DVT of 1.56 (95% CI 1.47-1.65) and for combined PE and DVT of 1.60 (95% CI 1.32-1.93). Asthma was associated with an increased risk of PE, DVT and combined PE and DVT.Thus, the inflammation conferred by asthma seems to have systemic (and not just local) prothrombotic effects with increased risk of both DVT and PE.

Asthma is associated with reduced fibrinolytic activity, abnormal clot architecture, and decreased clot retraction rate

The aim of this study was to assess whether steroid-naïve asthma modulates hemostasis. We evaluated the clot retraction rate (CRR), fibrinolysis rate (FR), clot density (CD) (by confocal microscopy), plasma levels of plasminogen activator inhibitor (PAI-1), and factor XIII (FXIII), NO in exhaled breath (FE_NO ), spirometry (FEV₁ ) and eosinophil count (EOS) in 36 patients with allergic, steroid-naïve asthma and in 34 healthy controls. We observed significantly (P < 0.001) reduced CRR, FR, and FEV₁ and increased FE_NO , EOS, PAI-1, FXIII, and CD in patients with asthma compared with controls. In patients with asthma, FR negatively correlated with CD, FXIII, PAI-1, FE_NO , and EOS and positively with FEV₁ . FXIII positively correlated with CD. Clot retraction rate negatively correlated with FE_NO and positively with FEV₁ (all P < 0.001). These novel findings suggest that asthma itself is associated with decreased CRR and reduced fibrinolytic potential resulting from alterations in clot architecture and elevated levels of plasma FXIII and PAI-1.