Role of Platelets in Rheumatic Chronic Autoimmune Inflammatory Diseases.

Platelets are essential in maintaining blood homeostasis and regulating several inflammatory processes. They constantly interact with immune cells, have immunoregulatory functions, and can affect, through immunologically active substances, endothelium, leukocytes, and other immune response components. In reverse, inflammatory and immune processes can activate platelets, which might be significant in autoimmune disease progression and arising complications. Thus, considering this interplay, targeting platelet activity may represent a new approach to treatment of autoimmune diseases. This review aims to highlight the role of platelets in the pathogenic mechanisms of the most frequent chronic autoimmune inflammatory diseases to identify gaps in current knowledge and to provide potential new targets for medical interventions.

A high-throughput liquid chromatography-tandem mass spectrometry method for simultaneous determination of direct oral anticoagulants in human plasma.

Direct oral anticoagulants are widely used in many indications to prevent thromboembolic events. Routine therapeutic monitoring is not required; however, there is increasing evidence suggesting the benefit of plasma level measurement in some situations. In addition, laboratory monitoring might help improve patient and drug non-compliance and thus individualize therapy. In the present study, we developed a sensitive and high throughput ultra-high-performance liquid chromatography-tandem mass spectrometry method for simultaneous quantification of apixaban, dabigatran, edoxaban, and rivaroxaban in human plasma. A one-step extraction procedure in 96-well formate for phospholipid and protein removal was used for sample pre-treatment, and analytes were separated using gradient elution over 4.2 min. Analytes were detected on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring mode. The method was validated according to the European Medicine Agency guideline for the selectivity, linearity, and lower limit of detection, precision and accuracy, matrix effects, extraction recovery, carryover, dilution integrity, and stability over a concentration range of 3.0-1000 ng/ml for all analytes. The validated method was applied to real clinical samples of patients treated with one of the drugs. Therefore, we can conclude that our method is suitable for therapeutic drug monitoring of direct oral anticoagulants.

MiR-126 and miR-146a as markers of type 2 diabetes mellitus: a pilot study.

INTRODUCTION: Despite known risk factors for developing type 2 diabetes mellitus (T2D), the research community still tries to discover new markers that would widen our diagnostic and therapeutic approach to diabetes. Therefore, research on microRNA (miR) in diabetes thrives. This study aimed to assess the utility of miR-126, miR-146a, and miR-375 as novel diagnostic markers for T2D. METHODS: We examined relative quantities of miR-126, miR-146a, and miR-375 in the serum of patients with established type 2 diabetes mellitus (n = 68) and compared these with a control group (n = 29). We also undertook a ROC analysis of significantly changed miR to examine their use as a diagnostic test. RESULTS: MiR-126 (p < 0.0001) and miR-146a (p = 0.0005) showed a statistically significant reduction in patients with type 2 diabetes mellitus. MiR-126 also proved to be an exceptional diagnostic test in our study cohort, with high sensitivity (91 %) and specificity (97 %). We did not find any difference in our study groups' relative quantities of miR-375. CONCLUSION: The study proved a statistically significant reduction of miR-126 and miR-146a in patients with T2D (Tab. 4, Fig. 6, Ref. 51). Text in PDF www.elis.sk Keywords: microRNA, epigenetics, genomics, type 2 diabetes mellitus, miR-126, miR-146a and miR-375.

Plasma levels of direct oral anticoagulants in atrial fibrillation patients at the time of embolic stroke: a pilot prospective multicenter study.

BACKGROUND: Patients with atrial fibrillation (AF) who are on long-term direct oral anticoagulants (DOAC) with low anti-Xa or anti-IIa levels may be at higher risk of recurrent stroke. However, no prospective post-marketing study has investigated these DOAC plasma levels at the time of embolic stroke. The aim of this study was to assess the anti-Xa (rivaroxaban, apixaban) and anti-IIa (dabigatran) plasma levels in DOAC-treated AF patients at the time of acute embolic stroke. PATIENTS AND METHODS: We prospectively identified 43 patients with AF on long-term DOAC who experienced embolic strokes. We compared the DOAC plasma levels of these patients with a control sample of 57 patients who tolerated long-term therapeutic dose DOAC therapy without any adverse event. DOAC levels were assessed with drug-specific anti-Xa chromogenic analysis (rivaroxaban, apixaban) and with Hemoclot Thrombin Inhibitor assay (dabigatran). RESULTS: Dabigatran-treated patients with stroke had significantly lower anti-IIa levels when compared with the trough (40.7 ± 36.9 vs. 85.4 ± 57.2 ng/mL, p < 0.05) and peak samples of the controls (40.7 ± 36.9 vs. 138.8 ± 78.7 ng/mL, p < 0.001). Similarly, there were significantly lower anti-Xa levels in apixaban-treated patients with stroke compared to the trough control samples (72.4 ± 46.7 vs. 119.9 ± 81.7 ng/mL, p < 0.05), and in rivaroxaban- and apixaban-treated patients when compared to peak control samples (rivaroxaban: 42.7 ± 31.9 vs. 177.6 ± 38.6 ng/mL, p < 0.001; apixaban: 72.4 ± 46.7 vs. 210.9 ± 88.7 ng/mL, p < 0.001). CONCLUSION: This observational study showed significantly lower anti-IIa and anti-Xa plasma levels in AF patients with embolic stroke compared to those who tolerated long-term therapeutic dose DOAC therapy.

Myocardial free wall rupture as a complication of STEMI.

Myocardial free wall rupture is a rare, but serious complication of acute myocardial infarction with high mortality. We present a case of a 64-year-old patient with this devastating complication of an anterior ST segment elevation myocardial infarction (STEMI) with a prolonged time delay. Cardiac surgery was not performed due to prohibitive surgical risk and predicted poor prognosis. We describe our successful therapeutic intervention consisting of immediate pericardial drainage, vasoactive and inotropic support, intraaortic balloon pump placement and continuous veno-venous hemodialysis. This combined therapy led to patient stabilization and after incremental clinical improvement the patient was able to return to a normal life. After several months a long-term mechanical circulatory support was implanted as a bridge to heart transplant.

ROTEM Testing for Direct Oral Anticoagulants.

Direct oral anticoagulants (DOACs) are increasingly used worldwide for the prevention of stroke in patients with atrial fibrillation and to prevent or treat venous thromboembolism. In situations such as serious bleeding, the need for urgent surgery/intervention or the management of a thromboembolic event, the laboratory measurement of DOACs levels or anticoagulant activity may be required. Rotational thromboelastometry (ROTEM) is a viscoelastic hemostatic assay (VHA) which has been used in emergencies (trauma and obstetrics), and surgical procedures (cardiac surgery and liver transplants), but experience with this assay in DOACs-treated patients is still limited. This article reviews the use of ROTEM in the setting of DOACs therapy, focusing on DOACs-associated bleeding and the use of this VHA for the management of reversal strategies for DOACs-associated anticoagulation.

Direct Oral Anticoagulants Plasma Levels in Patients with Atrial Fibrillation at the Time of Bleeding: A Pilot Prospective Study.

ABSTRACT: Patients with atrial fibrillation (AF) on long-term direct oral anticoagulants (DOACs) may be at higher risk of bleeding because of higher anti-Xa or anti-IIa levels. However, there is no postmarketing study investigating these DOAC plasma levels at the time of bleeding. The aim of this study was to evaluate DOAC levels at the time of a bleeding emergency. We analyzed 5440 patients examined at our Emergency Department in from April 1, 2019, to September 30, 2019. During this period, we prospective identified 105 consecutive patients with bleeding while on long-term antithrombotic therapy; 49 patients had AF on DOACs. We compared DOAC levels in patients who bled against a control sample of 55 patients who tolerated long-term high dose DOAC therapy without any emergency. Samples of these patients were tested with drug-specific anti-Xa chromogenic analysis (rivaroxaban and apixaban) and with Hemoclot Thrombin Inhibitor assay (dabigatran). Dabigatran-treated patients who bled had significantly higher anti-IIa levels when compared with trough (261.4 ± 163.7 vs. 85.4 ± 57.2 ng/mL, P < 0.001) and peak samples of controls (261.4 ± 163.7 vs. 138.8 ± 78.7 ng/mL, P < 0.05). Similarly, there were significantly higher anti-Xa levels in rivaroxaban-treated and apixaban-treated patients with bleeding compared with trough control samples (rivaroxaban: 245.9 ± 150.2 vs. 52.5 ± 36.4 ng/mL, P <0.001 and apixaban: 311.8 ± 142.5 vs. 119.9 ± 81.7 ng/mL, P < 0.001), as well as in apixaban-treated patients when compared with peak control samples (311.8 ± 142.5 vs. 210.9 ± 88.7 ng/mL, P < 0.05). Finally, rivaroxaban anti-Xa levels in patients who bled tended to be higher compared with peak control samples (245.9 ± 150.2 vs. 177.6 ± 38.6 ng/mL, P = 0.13). This observational study showed a significant difference in anti-IIa and anti-Xa plasma levels in patients with AF with bleeding complications compared with those who tolerated long-term high-dose DOAC therapy without bleeding complications.

Apixaban: An Optimal Agent for the Treatment of Cancer-Associated Venous Thromboembolism?

BACKGROUND: Apixaban, a direct inhibitor of activated coagulation factor X (FXaI), is being frequently selected for treatment and prevention of venous thromboembolism (VTE). Several reports about possible use of oral FXaI in patients with cancer-associated VTE (CA-VTE) have been published recently. AREAS OF UNCERTAINTY: The efficacy/safety profile of oral FXaI anticoagulation in patients with CA-VTE seems promising; however, several problems remain unanswered. The pharmacologic profile of apixaban could prefer this agent for the treatment of CA-VTE. DATA SOURCES: Currently available medical literature was searched and reviewed to summarize data regarding the use of apixaban for the prevention and treatment of cancer-associated VTE. RESULTS: Apixaban therapy in patients with cancer and VTE is expected to increase as clinicians gain more experience and reassurance with data from real-world studies that are generally promising. Several studies demonstrated that apixaban exhibits noninferiority to warfarin and low molecular weight heparin in preventing recurrent thrombosis in cancer-associated VTE. Nevertheless, there are still concerns regarding the bleeding associated with apixaban therapy, and regarding the optimal management of these bleeding emergencies. THERAPEUTIC OPINION: Although currently available evidence confirms the noninferiority of apixaban for reduction of the risk of recurrent VTE in patients with cancer; there are still concerns regarding the safety, especially in selected subpopulations of these patients.

Use of Fibrinogen Determination Methods in Differential Diagnosis of Hypofibrinogenemia and Dysfibrinogenemia.

BACKGROUND: Fibrinogen plays an important role in hemostasis. The normal concentration of fibrinogen in blood plasma is between 1.8 - 4.2 g/L. Decreased fibrinogen levels are observed in congenital afibrinogenemia, hypofibrinogenemia, dysfibrinogenemia, disseminated intravascular coagulation, fibrinolytic therapy, some more severe hepatic parenchymal disorders, and increased blood loss. Elevated fibrinogen levels occur in inflammatory diseases and neoplastic diseases, in pregnancy, and postoperative conditions. Functional fibrinogen measurement is also one of the basic coagulation screening tests. The fibrinogen antigen assay is used to distinguish between qualitative and quantitative fibrinogen disorders. METHODS: The aim of the study was the use of fibrinogen determination methods in differential diagnosis of hypofibrinogenemia and dysfibrinogenemia, statistical evaluation and determine the relationship of fibrinogen Clauss assay, prothrombin time (PT) derived fibrinogen assay, and fibrinogen antigen in the group of 60 patients with congenital fibrinogen disorders (n = 40 dysfibrinogenemia; n = 20 hypofibrinogenemia). RESULTS: The results measured by the PT-derived fibrinogen assay were approximately four times higher compared to the fibrinogen Clauss assay in the group of patients with dysfibrinogenemia. In patients with hypofibrinogenemia, there is a correlation (r = 0.9016) between the fibrinogen Clauss assay and PT-derived fibrinogen assay with a statistical significance of p < 0.0001. Using a linear or quadratic interpolation function, we were able to determine the fibrinogen Clauss assay and the fibrinogen antigen assay before analysis. CONCLUSIONS: The higher level of the PT-derived fibrinogen assay compared to the fibrinogen Clauss assay in the group of patients with dysfibrinogenemia may pose a greater risk to asymptomatic patients who require diagnosis and treatment in case of bleeding. The fibrinogen value using the PT-derived fibrinogen assay could erroneously give a normal level. The use of the interpolation function is important to estimate the value of fibrinogen activity and antigen before the analysis itself by the Clauss assay or analysis by the fibrinogen antigen assay.

The Effect of Proton Pump Inhibitor Withdrawal on Dabigatran Etexilate Plasma Levels in Patients With Atrial Fibrillation: A Washout Study.

BACKGROUND: Several studies demonstrated that proton pump inhibitors (PPIs) co-administrated with dabigatran in patients with atrial fibrillation (AF) decreased dabigatran trough and peak plasma levels. However, it is still unknown whether this interaction is reversible or not, and whether the withdrawal of PPI would lead to normalization of dabigatran plasma levels. AIM OF STUDY: The aim of this study was to determine the effect of PPI withdrawal on dabigatran plasma levels in patients with AF. METHODS: This pilot prospective study enrolled 23 AF patients on long-term dabigatran and PPI therapy (omeprazole 20 mg twice daily or pantoprazole 40 mg once daily). Dabigatran trough and peak levels (ng/mL) were tested on PPI and after a 2-week period of PPI withdrawal with Hemoclot Thrombin Inhibitor Assay. RESULTS: The analysis of dabigatran plasma levels demonstrated significant elevation in trough dabigatran levels after 2 weeks of PPI withdrawal (97.2 ± 79.7 vs. 163.8 ± 105.5 ng/mL; P < 0.05). Moreover, significantly higher peak dabigatran levels were observed after 2 weeks of PPI withdrawal (142.4 ± 102.8 vs. 255 ± 129.5 ng/mL; P ≤ 0.001). CONCLUSIONS: This study showed that a 2-week period of PPI withdrawal lead to a significant increase in dabigatran trough and peak plasma levels in patients with AF.

Proton Pump Inhibitors and Dabigatran Therapy: Impact on Gastric Bleeding and Dabigatran Plasma Levels.

Dabigatran etexilate, a direct thrombin inhibitor, is now frequently used for long-term pharmacological prevention of stroke or systemic embolism in patients with atrial fibrillation. However, such long-term dabigatran therapy (DT) significantly increases the risk of upper gastrointestinal (GI) bleeding. This increased risk of gastric bleeds might be reduced with gastroprotective agents, such as proton pump inhibitors (PPIs). PPIs coadministrated with dabigatran reduce the risk of upper GI bleeding in patients on long-term oral DT. Nevertheless, there is heated discussion regarding interactions between PPI and dabigatran that lead to decreases in dabigatran plasma levels. This article reviews up to date data about the risk of gastric bleeding on dabigatran, the impact of PPI on the reduction of gastric bleeding, and the interaction between PPI and dabigatran leading to decreased dabigatran plasma levels.

The Impact of Proton Pump Inhibition on Dabigatran Levels in Patients With Atrial Fibrillation.

BACKGROUND: Proton pump inhibition (PPI) administrated together with dabigatran reduces the risk of gastrointestinal hemorrhage. However, there is a discussion regarding possible PPI-dabigatran interaction that may reduce the efficacy of this therapy. STUDY QUESTION: To determine the impact of concomitant PPI on dabigatran plasma levels in patients with nonvalvular atrial fibrillation (NV-AF). STUDY DESIGN: A pilot prospective study in patients with NV-AF on dabigatran therapy was performed; 31 patients were enrolled. PPI with either omeprazole or pantoprazole was administrated in 19 patients. MEASURES AND OUTCOMES: Blood samples were taken for the assessment of the dabigatran trough and peak levels. Dabigatran concentration was measured with the Hemoclot Thrombin Inhibitor Assay. RESULTS: There were significant differences in dabigatran trough level comparing patients treated with PPI and patients without PPI (58.86 ± 36.76 ng/mL vs. 110.72 ± 88.47 ng/mL, P < 0.05). Similarly, there were significant differences in dabigatran peak level between compared groups (88.0 ± 20.5 ng/mL vs. 174.4 ± 139.64 ng/mL, P < 0.05). CONCLUSIONS: This pilot study demonstrated the interaction between PPI and dabigatran levels in patients with NV-AF.

Does proton pump inhibition change the on-treatment anti-Xa activity in xabans-treated patients with atrial fibrillation? A pilot study.

Proton pump inhibition (PPI) reduces gastrointestinal bleeding on direct oral anticoagulants. However, PPI may affect dabigatran on-treatment levels; and there is no information regarding the effect of PPI on xabans on-treatment activity. Thus, the aim of this study was to determine the impact of PPI on therapeutic anti-Xa activity in rivaroxaban- and apixaban-treated patients with atrial fibrillation (AF). This single-centre pilot prospective study enrolled 77 consecutive xabans-treated patients (42 rivaroxaban-treated and 35 apixaban-treated patients) with AF. PPI was administrated in 44 patients. Trough and peak anti-Xa activity was assessed with factor Xa-calibrated anti-Xa chromogenic analysis. There were no significant differences in trough anti-Xa activity comparing PPI-treated patients and patients without PPI (80.5 ± 66.5 ng/mL in PPI group vs. 71.6 ± 64.1 ng/mL in non-PPI group, p = 0.57, Table 2). Similarly, there were no significant differences in peak anti-Xa activity between compared groups (175.2 ± 102.5 ng/mL in PPI group vs. 202.9 ± 84.1 ng/mL in non-PPI group, p = 0.21). This pilot study did not reveal significant changes in xabans on-treatment anti-Xa activity according the PPI status.

Apixaban: a novel agent to treat heparin induced thrombocytopenia and to prevent embolism in patient with atrial fibrillation after multiple valve replacement?

Very limited but promising experiences with the use of direct factor Xa inhibitors for the treatment of heparin-induced thrombocytopenia (HIT) have been reported. This contribution features our first experience with the use of apixaban (without a pre-treatment with parenteral anticoagulant) to treat a case of HIT which developed in a patient after multiple heart replacement surgery. Apixaban was effective, well tolerated and safe. An apixaban-calibrated chromogenic anti-Xa activity assessment was used to monitor apixaban activity throughout the therapy. Patient continued on apixaban for the prevention of thrombosis in the settings of atrial fibrillation. No ischemic or bleeding events occurred during the clinical follow up and the platelet count was stable. Our experience suggests that apixaban might be effectively used for the treatment of HIT and for the long-term prevention of embolism in patients after multiple valve replacement with biological prostheses and atrial fibrillation.

Direct Oral Anticoagulants: Novel Approach for the Treatment of Thrombosis in Pediatric Patients?

Venous thromboembolism (VTE) is a rare, but life-threatening disease in those who have not reached their adulthood. This condition is usually treated with heparin or low molecular weight heparins which require parenteral administration and, in case of unfractionated heparin, also frequent laboratory monitoring and dose adjustment. Direct oral anticoagulants (DOACs)-direct thrombin inhibitor dabigatran, and direct oral factor Xa inhibitors rivaroxaban, apixaban, and edoxaban-are currently frequently used for the prevention and treatment of VTE in adult population. In fact, these agents offer several advantages compared to traditional agents, such as oral route of administration, short on-set and off-set of action, predictable pharmacologic profile with low risk of food and drug interactions, and no need for routine laboratory assessment of anticoagulant activity. However, clinical experience with these directly acting oral anticoagulants in pediatric population is very limited as these drugs had been tested and are used mostly in adult individuals. This article reviews the current data from pre- and post-marketing studies reporting the use of DOACs for the treatment of VTE in pediatric patients.

Proton Pump Inhibition in Patients Treated With Novel Antithrombotic Drugs: Should We Worry About Thrombosis?

Proton pump inhibition (PPI) administered together with antiplatelet and anticoagulant agents reduces the risk of gastrointestinal hemorrhage. Several novel antithrombotic agents have been recently introduced for patients with acute coronary syndrome (prasugrel and ticagrelor) or for patients requiring long-term anticoagulation (dabigatran, rivaroxaban, apixaban, edoxaban, and betrixaban). In fact, these agents might offer even stronger inhibition of platelets or coagulation compared with older agents; therefore, the need for gastroprotection might be even stronger when these new agents are used for long-term antithrombotic therapy. On the contrary, there are several reports regarding an adverse interaction between PPI and antithrombotic agents connected with a reduction in antithrombotic therapy on-treatment levels, implicating a higher risk of thrombosis. This interaction was demonstrated in clopidogrel-treated patients and more recently also in dabigatran-treated patients. This article discusses a possible novel antithrombotic therapy/PPI interaction leading to higher risk of thrombosis.

Platelet Aggregation in Direct Oral Factor Xa Inhibitors-treated Patients With Atrial Fibrillation: A Pilot Study.

BACKGROUND: Activated factor X (factor Xa) plays an important role in regulation of platelets. The aim of this study was to test the effect of direct oral factor Xa inhibitors-rivaroxaban and apixaban-on platelet aggregation in patients with nonvalvular atrial fibrillation. PATIENTS AND METHODS: This single-center pilot study enrolled 21 factor Xa inhibitors-treated (9 rivaroxaban-treated and 12 apixaban-treated) patients with nonvalvular atrial fibrillation. The trough and peak samples of these patients were tested for adenosine diphosphate (ADP)-induced, epinephrine-induced, and collagen-induced platelet aggregation with light transmission aggregometry, and with factor Xa-calibrated anti-Xa chromogenic analysis. RESULTS: The detected trough anti-Xa activity was 57.5 ± 43.4 µg/L. There was a significant increase in peak anti-Xa activity to 175.9 ± 119.6 µg/L (P < 0.001) observed. The platelet aggregation was reduced with reduced inductor concentration. However, no significant changes in ADP-induced, or in epinephrine-induced, or in collagen-induced platelet aggregation were seen comparing trough and peak sample. There were no significant differences in anti-Xa activity or in platelet aggregation comparing rivaroxaban-treated and apixaban-treated patients. CONCLUSIONS: This study showed that factor Xa inhibition does not affect ADP-induced, epinephrine-induced, and collagen-induced platelet aggregation.

Does Pantoprazole Affect the On-Treatment Platelet Reactivity in Patients With Acute STEMI Treated With ADP Receptor Blockers?-A Pilot Prospective Study.

BACKGROUND: Proton pump inhibition (PPI) administrated together with adenosine diphosphate (ADP) receptor blockers (ADPRB) significantly reduces the risk of gastrointestinal bleeding. Nevertheless, there is a heated discussion about an interaction between PPI and ADPRB that leads to high on-treatment platelet reactivity (HTPR). STUDY QUESTION: Is there a relationship between pantoprazole PPI and HTPR on ADPRB therapy in patients with acute ST-elevation myocardial infarction (STEMI). METHODS: Single center pilot study in patients with acute STEMI was performed. This study enrolled totally 87 patients (34 clopidogrel-treated and 53 new ADPRB-treated patients). Pantoprazole was administrated in 33 patients. HTPR was detected with ADP-induced light transmission aggregometry and vasodilator-stimulated phosphoprotein phosphorylation analysis. Samples were taken before coronary angiography (sample 1) and on the next day after the procedure (sample 2). RESULTS: No significant differences were found in pantoprazole-treated patients and patients without PPI neither in sample 1 (59.2 ± 29.5% vs. 54.9 ± 22.7%, P = 0.49) nor in sample 2 (43.8 ± 27.2% vs. 37.0 ± 22.9%, P = 0.30). Similarly, there were no significant differences in the platelet reactivity index of vasodilator-stimulated phosphoprotein phosphorylation in both samples (sample 1: 53.3 ± 29.8% vs. 65.0 ± 20.5%, P = 0.11; sample 2: 30.8 ± 27.1% vs. 40.6 ± 27.5%, P = 0.19). A comparison of clopidogrel and new ADP receptor blockers in patients on pantoprazole PPI did not reveal significant differences in on-treatment platelet reactivity. CONCLUSIONS: This study did not reveal interaction between pantoprazole and ADPRB in patients with acute STEMI.