Blood Thrombogenicity Research Articles

Protection by L-arginine against Epinephrine-induced Arrhythmia and Cardiotoxicity

Nitric oxide is important in control of coronary blood flow, cardiomyocyte contractility, cardiac rhythm, and thrombogenicity. We aimed to investigate the effect of the nitric oxide precursor L-arginine on cardiac arrhythmia and myocardial injury induced by epinephrine in male Sprague-Dawley rats. The possible modulation of L-arginine effects by methylene blue (MethyB), a nitric oxide synthase inhibitor was also examined. Cardiac arrhythmia was induced with 10μg/kg epinephrine given intravenously (i.v.). L-arginine (200mg/kg) or L-arginine and MethyB (100mg/kg) were intraperitoneally (i.p.) administered prior to i.v. epinephrine. Other groups received i.p. saline, only L-arginine or only MethyB (100mg/kg). Results showed that compared with the saline control, epinephrine caused a significant bradycardia (188.7±24.4 vs. 405.6±1.19beats/min), increased QRS duration (0.039±0.006 vs. 0.0185±0.0001s), decreased R wave amplitude (0.18±0.01 vs. 0.23±0.011mv), and ventricular extrasystoles. L-arginine alone showed no significant effect on heart rate (380.8±10.0 vs. 405.6±1.19beats/min) but increased QRS duration (0.029±0.0002 vs. 0.0185±0.0001s), and R wave amplitude (0.47±0.01 vs. 0.23±0.011mv). L-arginine given prior to epinephrine prevented bradycardia, shortened the duration of arrhythmia and decreased the number of extrasystoles. The administration of L-arginine and MethyB almost completely suppressed epinephrine-induced ventricular arrhythmias. Epinephrine caused severe degeneration of muscle fibres, widening of intercellular spaces, cellular infiltrations and interstitial haemorrhage. L-arginine markedly attenuated, while L-arginine/MethyB completely prevented these changes. It is concluded that L-arginine protects against cardiac arrhythmias and cardiac tissue damage caused by epinephrine.

Thrombogenicity of biodegradable metals

Biodegradable metals offer a promising means to ameliorate many of the long-term risks associated with vascular devices made of conventional biostable stent metals. While numerous biodegradable metal alloys have been developed and characterized in animal models, knowledge of their blood reactivity and thrombogenicity remains unknown. Metal hemocompatibility is particularly valuable because current generation drug-eluting stents pose a significant long-term thrombosis risk. In this study, four pure metals, widely used as degradable base materials (Fe, Zn, Mg, and Mo), and three alloys commonly used in cardiovascular devices [NiTi, CoCr, and stainless steel (SS)] were evaluated. This work examined how each of these metals activate platelets, coagulation factors, and inflammation using in vitro hemocompatibility assays and a clinically relevant ex vivo non-human primate arteriovenous shunt model. Testing found that while all metals promoted a downstream activation of platelets and coagulation in flowing whole blood, platelet and fibrin attachment to Mg was markedly reduced. Additionally, Fe and Mo trended toward higher platelet attachment and contact pathway activation. Overall, the results suggest that Mg may delay clot initiation, but not eliminate clot formation, indicating the importance of understanding thrombosis in Mg alloys that are currently being developed for clinical use as biodegradable stents.

Abstract 15625: Left Atrial Appendage Volumetric and Functional Assessment Using Cardiac CT-Derived Three-Dimensional Models

Introduction: The left atrial appendage (LAA) is the most common site of thrombus formation in atrial fibrillation (AF) patients who develop strokes, yet its dynamic volumetric parameters remain uncharacterized. We present a quantitative analysis of cardiac phase-specific LAA volumes and function using cardiac CT-derived three-dimensional (3D) models of 920 LAA segmentations. Methods: We measured LAA volumes at 10% increments of the cardiac cycle (R-R interval) in patients with AF and controls with sinus rhythm (SR). After identifying the LAA orifice using anatomical landmarks on multiplanar CT images, we performed computational LAA segmentation using specialized software. For precise mapping, we used iterative active region-growing and cutting tools to separate the LAA from surrounding structures. We used the resulting 3D model for volumetric assessment of the LAA during the cardiac cycle. Results: We analysed 580 LAA segmentations in patients with AF and 340 segmentations in patients with SR. Both groups displayed LAA volume increase from 0 to 40% of the cardiac cycle followed by a gradual decrease during diastole. LAA volumes were significantly higher in AF at 0%, 10%, 70%, 80%, and 90% of the cardiac cycle (p =0.01, 0.021, 0.047, 0.025 and 0.011, respectively). LAA volumetric variance within the AF group was significantly greater (p<0.001). LAA ejection fraction was significantly lower in AF compared to SR (40.8±16.1% vs 49.7±12.6%, p=0.003). Polynomial plots of incremental volume changes showed an accelerated rate of LAA filling in early systole in the SR, which was significantly dampened in AF. Conclusions: We present the first comparative analysis of LAA volumetric and functional assessment in patients with AF and SR. We conclude that impaired LAA filling and emptying in AF can contribute to blood stasis and thrombogenicity. Further investigations into the utility of LAA metrics as prognostic and risk-stratification tools in patients with AF are warranted.

Endometriosis is associated with an increased whole-blood thrombogenicity detected by a novel automated microchip flow-chamber system (T-TAS®).

Potential thrombotic and antifibrinolytic influence of endometriosis on haemostasis has been recently reported in the literature, as well as increased cardiovascular morbidity in women suffering from the disease. We performed a pilot study to assess the influence of endometriosis on the thrombus formation process under in vitro flow conditions. This study compared women with confirmed endometriosis (n = 23) surgically and control healthy subjects (n = 10). In both groups, the same exclusion criteria were used: a prior episode of thrombosis diagnosed as acquired or inherited thrombophilia, neoplasm, and an uncertain family history of thrombosis. We evaluated the whole blood thrombogenicity using T-TAS® at a shear rate of 240 s-1 (Total-Thrombus Analysis System, Zacros, Japan). The blood clot formation initiation time (T10) and occlusion time (OT) were significantly shortened in the endometriosis group (p < 0.05). The area under the curve (AUC30) of blood clot time formation values (BCTF) was substantially higher in the patients suffering from a disease (p = 0.03). An increase in AUC (TTAS) values by 100 increases the risk of developing endometriosis by 1.56-fold [adjusted OR = 1.56 (p = 0.01); (95% CI: 1.10-2.18)]. Inflammatory markers (neutrophil-to-lymphocyte ratio (NLR), and the leucocyte, neutrophil, basophil, and neutrophil concentrations) were also substantially higher in the endometriosis group (p < 0.05). The alteration of the T-TAS® and NLR values supports the thesis of a shift of the equilibrium towards thrombosis in women who have endometriosis. This phenomenon links to a state of chronic inflammation. It is detectable using a novel system for the quantitative assessment of the platelet thrombus formation process under flow conditions in vitro.

Impact of exposure to ambient fine particulate matter-bound polycyclic aromatic hydrocarbons on blood thrombogenicity in adults

Objective: To investigate the effects of exposure to ambient fine particulate matter-bound polycyclic aromatic hydrocarbons on blood coagulation in adults. Methods: A total of 73 adult volunteers were recruited in a cohort study and had four clinical visits from November 2014 to January 2016. Blood samples were obtained and used to measure biomarkers of blood thrombogenicity, including soluble CD40 Ligand (sCD40L), soluble P-selection (sCD62P) and Fibrinogen (FIB). White blood cell (WBC), 8-Hydroxy-2'-Deoxyguanosine (8-OHdG), matrix metalloproteinase-2 (MMP-2) and HDL cholesterol efflux capacity (HDL-CEC) were also determined. Daily concentrations of ambient fine particulate matter-bound polycyclic aromatic hydrocarbons (PAHs) were measured throughout the study period, and positive matrix factorization (PMF) approach was used to identity PAHs sources. Linear mixed-effect models including single-pollutant model, two-pollutant model and stratification analysis were constructed to estimate the effects of exposure to ambient fine particulate matter-bound PAHs on blood thrombogenicity in adults after adjusting for potential confounders. Results: The mean age of participants was (23.3±5.4) years. During the study period, the median level of PM2.5-bound PAHs was (55.29±74.99) ng/m3. Six sources of PM2.5-bound PAHs were identified by PMF, with traffic sources contributing more than 50%. The linear mixed-effect model showed that PAHs exposure had a significant effect on elevated blood thrombogenicity. Significant elevations in sCD40L, sCD62P and FIB associated with per IQR increase (60.33 ng/m3) in exposure to PAHs were 14.36% (95%CI:6.94%-22.28%), 9.33% (95%CI: 1.71%-17.51%) and 2.07% (95%CI:0.44%-2.07%) at prior 5 days, respectively. Blood thrombogenicity levels were significantly and positively correlated with source-specific PAHs, especially gasoline vehicle emissions, diesel vehicle emission and coal burning at prior 1 or 5 days. Stronger associations between PAHs and increased blood thrombogenicity were found in participants with high plaque vulnerability, reduced HDL function, and high levels of inflammation and oxidative stress. Conclusion: Acute exposure to ambient fine particulate matter-bound PAHs, especially PAHs from traffic sources may promote blood thrombogenicity in adults, and PAHs have stronger effects on participants with reduced vascular function and high levels of inflammation and oxidative stress.

In vivo safety study using radiation at wavelengths and dosages relevant to intravascular imaging.

.SignificanceIntravascular photoacoustic (IVPA) imaging can identify native lipid in atherosclerotic plaques in vivo. However, the large number of laser pulses required to produce 3D images is a safety concern that has not been fully addressed.AimWe aim to evaluate if irradiation at wavelengths and dosages relevant to IVPA imaging causes target vessel damage.ApproachWe irradiate the carotid artery of swine at one of several energy dosages using radiation at 1064 or 1720 nm and use histological evaluation by a pathologist to identify dose-dependent damage.ResultsMedia necrosis was the only dose-dependent form of injury. Damage was present at a cumulative fluence of when using 1720 nm light. Damage was more equivocally identified at using 1064 nm.ConclusionsIn prior work, IVPA imaging of native lipid in swine has been successfully conducted below the damage thresholds identified. This indicates that it will be possible to use IVPA imaging in a clinical setting without damaging vessel tissue. Future work should determine if irradiation causes an increase in blood thrombogenicity and confirm whether damaged tissue will heal over longer time points.

Temporary Rise in Blood Thrombogenicity in Patients with Acute Myocardial Infarction.

Objective Although blood thrombogenicity seems to be one of the determinant factors for the development of acute myocardial infarction (MI), it has not been dealt with in-depth. This study aimed to investigate blood thrombogenicity and its change in acute MI patients. Methods and Results We designed a prospective, observational study that included 51 acute MI patients and 83 stable coronary artery disease (CAD) patients who underwent cardiac catheterization, comparing thrombogenicity of the whole blood between: (1) acute MI patients and stable CAD patients; and (2) acute and chronic phase in MI patients. Blood thrombogenicity was evaluated by the Total Thrombus-Formation Analysis System (T-TAS) using the area under the flow pressure curve (AUC 30 ) for the AR-chip. Acute MI patients had significantly higher AUC 30 than stable CAD patients (median [interquartile range], 1,771 [1,585–1,884] vs. 1,677 [1,527–1,756], p = 0.010). Multivariate regression analysis identified acute MI with initial TIMI flow grade 0/1 as an independent determinant of high AUC 30 ( β = 0.211, p = 0.013). In acute MI patients, AUC 30 decreased significantly from acute to chronic phase (1,859 [1,550–2,008] to 1,521 [1,328–1,745], p = 0.001). Conclusion Blood thrombogenicity was significantly higher in acute MI patients than in stable CAD patients. Acute MI with initial TIMI flow grade 0/1 was significantly associated with high blood thrombogenicity by multivariate analysis. In acute MI patients, blood thrombogenicity was temporarily higher in acute phase than in chronic phase.

Gene polymorphisms role of blood coagulation in myocardial infarction development in patients with malignant tumors of thoracoabdominal localization

Aim. To evaluate the role of polymorphic variants of blood coagulation genes (F2, F5, F7, F13, FGB, ITGA2, ITGB3, PAI-1) in the development of myocardial infarction in patients with malignant tumors of thoracoabdominal localization.&#x0D; Materials and methods. The study included 143 patients with thoracoabdominal tumors operated in the oncological Department of surgical methods of treatment No.11 (thoracic Oncology) of the thoracoabdominal Department of the Blokhin National Medical Research Center of Oncology in 20182019. The study group (n=62) consisted of patients with a history of myocardial infarction or in the perioperative period. The control group (n=81) included patients who did not have severe concomitant cardiovascular diseases, including a family history. Molecular genetic study to determine the gene polymorphisms of blood coagulation were performed in the laboratory of clinical oncogenetic of the Blokhin National Medical Research Center of Oncology with use of reagents Cardiogenetic Thrombophilia (LLC DNA-Technology, Russia, RU No. FSR 2010/08414 from 22.11.2016).&#x0D; Results. In the study group, 90.3% (n=56) of cases showed polymorphism -675 5G4G of the PAI-1 gene (SERPINE1, a plasminogen activator inhibitor) associated with a decrease in the activity of the fibrinolytic system and an increased risk of thrombosis. In the control group, this mutation was observed significantly less frequently in 67.9% (n=55) of cases (p0.001). In the group of patients with myocardial infarction, polymorphism 807 CT of the ITGA2 (integrin a2) gene responsible for platelet aggregation was detected in 66.1% (n=41) compared to 19.8% (n=16) in the control group (p0.0001). Polymorphism 1565 TC of the ITGB3 gene (platelet-derived fibrinogen receptor) responsible for fibrinogen-induced platelet aggregation was observed in 25.8% (n=16) of cases in the group of patients with myocardial infarction and in 12.4% (n=10) of cases in the group of patients without concomitant severe cardiovascular pathology (p0.05). In 48.4% (n=30) of patients of the study group, genetic disorders of the FGB gene (fibrinogen, missense mutation -455GA) were also registered, which resulted in the development of dysfibrinogenemia, leading to increased blood thrombogenicity; in the control group, this mutation was 2 times less common 25.9% (n=21) of cases (p0.01). Polymorphism 1691 GA of the F5 gene (coagulation factor V, Leiden factor), which is considered one of the most significant genetic risk factors for thrombosis in Caucasians, was detected in 4.8% (n=3) of cases in the study group, while this mutation was not found in the control group. Polymorphism 20210 GA of the F2 gene (coagulation factor II prothrombin), which is a key protein of the coagulation cascade associated with increased blood levels of prothrombin, was observed in 3.2% (n=2) of patients after myocardial infarction; in the control group, the carrier of this polymorphism was not found in any case. Disorders in the genes that promote hypocoagulation were also noted. Among patients who had a myocardial infarction, polymorphism 10976 GA of the F7 gene (coagulation factor VII) was detected in 17.7% (n=11) of cases, polymorphism 103 GT of the F13 gene (coagulation factor XIII) in 41.9% (n=26) of cases. In patients of the control group, these genetic aberrations were found: in 18.5% (n=15) of cases a mutation in the F7 gene (p0.05) and in 45.7% (n=37) in the F13 gene (p0.05), respectively.&#x0D; Conclusion. Based on the results of a molecular genetic study of factors associated with thrombogenic risk, a statistically significant difference in the frequency of occurrence of polymorphisms of genes involved in the process of thrombosis (polymorphisms: -455 GA of the FGB gene, 807 CT of the ITGA2 gene, 1565 TC of the ITGB3 gene, -675 5G4G of the PAI-1 gene) in patients who had a myocardial infarction, compared with patients without severe concomitant cardiovascular diseases. The frequency of 1691 GA polymorphism of the F5 gene, one of the most significant genetic risk factors for thrombosis, reached 4.8%. The obtained data on the use of molecular genetic markers of thrombophilia in patients with malignant tumors of thoracoabdominal localization allow us to identify a group of patients with a high risk of developing perioperative myocardial infarction and take additional measures for the prevention and treatment of thrombotic complications.

Hemostatic and antibacterial PVA/Kaolin composite sponges loaded with penicillin\u2013streptomycin for wound dressing applications

Hemorrhage is the major hindrance over the wound healing, which triggers microbial infections and might provoke traumatic death. Herein, new hemostatic and antibacterial PVA/Kaolin composite sponges were crosslinked using a freeze-thawing approach and boosted by penicillin–streptomycin (Pen-Strep). Physicochemical characteristics of developed membranes were analyzed adopting Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), a thermal gravimetric analyzer (TGA), and differential scanning calorimetry (DSC). Furthermore, the impacts of kaolin concentrations on porosity, swelling behavior, gel fraction, and degradation of the membranes were investigated. SEM analyses revealed a spongy-like structure of hydrogels associated with high dispersion of kaolin inside PVA matrix. The thermal characteristics of PVA/Kaolin were significantly ameliorated compared to the prime PVA. Moreover, the results exhibited significant variations of swelling performance, surface roughness and pore capacity due to the alterations of kaolin contents. Besides, the adhesive strength ability was manifestly enhanced for PVA-K0.1 sponge. Biomedical evaluations including antibacterial activity, blood clotting index and thrombogenicity of the membranes were studied. The contact of PVA/Kaolin to blood revealed notable augmentation in blood clotting. Furthermore, the incorporation of kaolin into PVA presented mild diminution in antibacterial activities. Moreover, PVA/Kaolin composites illustrated no cellular toxicity towards fibroblast cells. These remarkable features substantiate that the PVA-K0.1 sponge could be applied as a multifunctional wound dressing.

The Apex bileaflet mechanical heart valve

Mechanical Heart Valves (MHVs) are known for their excellent lifespan and feasibly are the most reliable and stable valves amongst all prosthetic valves. Successful bileaflet MHVs such as the St. Jude Medical (SJM) are known for providing central blood flow and minimal pressure drop across the valve. However, due to their non-physiological flow conditions, they still suffer from hemodynamic complications, that is, red blood cell (RBC) lysis and/or thrombogenicity, to date. Our hypothesis is that the design of MHVs can be improved so that their hemodynamics can be comparable to those of tissue valves. In this study, a new concept for the design of MHVs is proposed. To accomplish this, we identified the major design limitations of bileaflet MHVs, such as the gold standard SJM valve as well as the believed contributing factors to their thrombogenicity. We developed a novel design architecture for bileaflet MHVs that addressed these limitations, and from it, the Apex Valve (AV). Our experimental assessment of the AV found that its hemodynamics were closer to that of a bioprosthetic valve than of a bileaflet MHV. This design has been filed as a US Provisional Patent.

Design, Manufacturing Technology and In-Vitro Evaluation of Original, Polyurethane, Petal Valves for Application in Pulsating Ventricular Assist Devices.

Minimizing of the life-threatening thrombo-emboli formation in pulsatile heart assist devices by a new biomimetic heart valve design is presently one of the most important problems in medicine. As part of this work, an original valve structure was proposed intended for pneumatic, extracorporeal ventricular assist devices. The valve design allows for direct integration with other parts of the pulsating blood pump. Strengthening in the form of the titanium or steel frame has been introduced into the polyurethane lagging, which allows for maintaining material continuity and eliminating the risk of blood clotting. The prototype of the valve was made by the injection molding method assisted by numerical simulation of this process. The prototype was introduced into a modified pulsating, extracorporeal heart assist pump ReligaHeart EXT (developed for tilting disc valves) and examined in-vitro using the “artificial patient” model in order to determine hydrodynamic properties of the valve in the environment similar to physiological conditions. Fundamental blood tests, like hemolysis and thrombogenicity have been carried out. Very low backflow through the closed valve was observed despite their slight distortion due to pressure. On the basis of immunofluorescence tests, only slight activation of platelets was found on the inlet valve and slight increased risk of clotting of the outlet valve commissures as a result of poor valve leaflets assembling in the prototype device. No blood hemolysis was observed. Few of the clots formed only in places where the valve surfaces were not smooth enough.

Poor glycaemic control contributes to a shift towards prothrombotic and antifibrinolytic state in pregnant women with type 1 diabetes mellitus.

Thrombotic and antifibrinolytic influence of Diabetes mellitus type 1 (T1DM) on haemostasis have been well demonstrated. There has been no research assessing the influence of poor glycemic control on thrombus formation under flow conditions in vitro or in pregnant type 1 diabetic women to date. This study compared singleton pregnant T1DM women (n = 21) and control pregnant subjects without any metabolic disease (n = 15). The T1DM group was divided into two subgroups of sufficient (SGC-DM; HbA1c ≤6,5%,n = 15) and poor glycaemic control (PGC-DM; HbA1c >6,5%,n = 6). Evaluation of the whole blood thrombogenicity we assessed using T-TAS® at a shear rate of 240 s-1 (Total-Thrombus Analysis System, Zacros, Japan). Blood clot formation initiation time (T10) was significantly shortened in PGC-DM subgroup when compared to SGC-DM subgroup (p = 0,03). The area under the curve (AUC30) of blood clot time formation and the MPV (mean platelet volume) values were substantially higher in the PGC-DM subgroup in comparison to the SGC-DM group (p = 0,03). Negative correlations were noted between HbA1c and T10 values (p = 0,02) and between T10 and MPV values in the T1DM group (p = 0,04). Poor glycaemic control in T1DM subjects triggers a shift towards a prothrombotic and antifibrinolytic state. This phenomenon can be detected using the novel system for quantitative assessment of the platelet thrombus formation process under flow conditions in vitro. The alteration of T-TAS values in PGC-DM subgroup proves that a poor glycemic control-related shift of the equilibrium toward thrombogenesis occurs in this group of patients. Our findings need a further elucidation in research on more massive data sets to be confirmed.

Atherothrombotic stroke in women: blood thrombogenicity and the vascular wall

Introduction. Haemostasis and functional changes of the vascular wall are the strategic and actively developing aspects in the study of ischaemic stroke pathogenesis. The aim of current work was to examine the relationship between hormonal status, thrombogenic blood factors, and the structural and functional changes in the vascular wall in women after atherothrombotic stroke in the internal carotid territory. Materials and methods . Twenty-nine women (mean age 55 years) in the first 3 months after atherothrombotic stroke, diagnosed using the international TOAST criteria, were included in the study. The severity of neurological impairment was evaluated using the NIH Stroke Scale. The follicular stimulating hormone (FSH) and homocysteine levels, along with haemostasis parameters and rheological properties of red blood cells were examined. Ultrasound of the major arteries of the head, assessment of the elastic properties and mural shear stress in the common carotid artery, as well as evaluation of the vasomotor function of the brachial artery endothelium were conducted. Results. Clinical differences in the atherosclerotic stroke were found in women depending on their FSH levels: moderate and severe neurological impairments were noted when the FSG level was ³30 mIU/mL, while mild impairments were present when the FSG level was <30 mIU/mL. It was found that a high FSH level in women is associated with significant arterial hypertension, obesity and type 2 diabetes mellitus. The group of women with high FSH levels had elevated fibrinogen, homocysteine, von Willebrand factor, erythrocyte aggregation amplitude, along with the accelerated formation of 3D aggregates and increased erythrocyte aggregate strength. In women with insufficient estrogen production in the ovaries (FSH ³30 mIU/mL), the stiffness index of the common carotid artery wall was significantly higher, while the mural shear stress and endothelial vasomotor function were lower than in the group of women with preserved ovarian function. Conclusions. A link between menopause, increased blood thrombogenicity, and structural and functional changes in the vascular wall (increased stiffness, reduced mural shear stress and endothelial vasomotor function) was found in women after atherothrombotic stroke.

Menopausal hormone therapy, blood thrombogenicity, and development of white matter hyperintensities in women of the Kronos Early Estrogen Prevention Study.

Development of white matter hyperintensities (WMH) in the brain is associated with blood thrombogenicity in recently menopausal women. This study examined the influence of menopausal hormone treatments (MHTs) on this association. Measures of blood thrombogenicity were examined in women of the Kronos Early Estrogen Prevention Study (n = 95) who had brain magnetic resonance imaging before and during the 48 months of randomization to transdermal 17β-estradiol (n = 30), oral conjugated equine estrogen (n = 29) both with progesterone for 12 days per month or placebo pills and patch (n = 36). Principal components (PCs) analysis was used to reduce the dimensionality of 14 markers of platelet activation and blood thrombogenicity. The first 5 PCs were assessed for association with treatment and changes in WMH. Within-person slopes were obtained to capture the extent of WMH change for each woman. WMH increased in all groups over the 48 months (P = 0.044). The partial effect of PC1, representing an average of six thrombogenicity variables (microvesicles derived from endothelium, leukocytes, and monocytes, and positive for tissue factor and adhesion molecules) on WMH was significant (P = 0.003). PC3, reflecting a contrast of platelet microaggregates and adenosine triphosphate secretion versus total platelet count, differed across groups (P = 0.006) with higher scores in the oral conjugated equine estrogen group. The global association between PCs and WMH increase, however, did not differ significantly by MHT (P = 0.207 for interaction between MHT and PC's). In recently menopausal women, the type of MHT did not significantly influence the association of markers of blood thrombogenicity with development of WMH in the brain.

Waterpipe Tobacco Smoke Inhalation Triggers Thrombogenicity, Cardiac Inflammation and Oxidative Stress in Mice: Effects of Flavouring.

The consumption of water-pipe smoking (WPS) has been promoted by the use of flavoured tobacco. However, little is known about the impact of flavouring on the cardiovascular toxicity induced by WPS inhalation. Here, we compared the cardiovascular effects and underlying mechanism of actions of plain (P) (unflavoured) versus apple-flavoured (AF) WPS (30 minutes/day, 5 days/week for 1 month) in mice. Control mice were exposed to air. Both P- and AF-WPS inhalation induced an increase in systolic blood pressure, thrombogenicity and plasma concentration of fibrinogen and von Willebrand factor. In heart homogenates, AF-WPS inhalation caused an increase of 8-isoprostane and a decrease in the levels of reduced glutathione (GSH) and superoxide dismutase (SOD). Nevertheless, P-WPS decreased only the activity of SOD. The concentrations of tumour necrosis factor α and interleukin 1β were increased only in heart homogenates of mice exposed to AF-WPS. Although both P- and AF-WPS increased the concentration of troponin I in heart homogenates and induced DNA damage, the concentration of cleaved caspase 3 was only increased in mice exposed to AF-WPS. Immunohistochemical analysis of the hearts showed that both P- and AF- WPS inhalation decreased the expression of SOD. Moreover, the expression of nuclear factor erythroid-derived 2-like 2 at nuclear level in the heart was higher in both AF-WPS and P-WPS compared with control group, and the effect observed in AF-WPS group was more significant than that seen in P-WPS group. Likewise, the concentration of heme oxygenase-1 was significantly increased in both P-WPS and AF-WPS groups compared with control group, and the effect seen in AF-group was higher than that observed in P-WPS group. In conclusion, our findings showed that both P- and AF-WPS induce thrombogenicity and cardiac injury, and that this toxicity is potentiated by the presence of flavouring.

Ticagrelor With or Without Aspirin After PCI: The TWILIGHT Platelet Substudy

BackgroundAn evolving strategy in the setting of percutaneous coronary intervention (PCI) involves withdrawal of acetylsalicylic acid (ASA), or aspirin, while maintaining P2Y12 inhibition. However, the pharmacodynamic effects of this approach on blood thrombogenicity and platelet reactivity remain unknown. ObjectivesThis study sought to compare the antithrombotic potency of ticagrelor alone versus ticagrelor plus ASA among high-risk patients undergoing PCI with drug-eluting stents. MethodsThis was a mechanistic substudy within the TWILIGHT (Ticagrelor With Aspirin or Alone in High-Risk Patients After Coronary Intervention) trial, which randomized patients undergoing PCI to ticagrelor plus placebo versus ticagrelor plus ASA following 3 months of dual antiplatelet therapy. Substudy participants were enrolled after randomization, at which time ex vivo assays to quantify thrombus size under dynamic flow conditions and platelet reactivity were performed. Pharmacodynamic assessments were repeated 1 to 6 months thereafter. The primary endpoint was thrombus size at the post-randomization visit with platelet reactivity following stimuli to arachidonic acid, collagen, adenosine diphosphate, and thrombin as secondary endpoints. Results were analyzed using analysis of covariance. ResultsA total of 51 patients were enrolled, among whom 42 underwent perfusion assays at baseline and follow-up with a median time between studies of 1.5 months. The adjusted mean difference in post-randomization thrombus area was similar between groups: −218.2 μm2 (95% confidence interval [CI]: −575.9 to 139.9 μm2; p = 0.22). Markers sensitive to cyclo-oxygenase-1 blockade, including platelet reactivity in response to arachidonic acid (mean difference: 10.9 U; 95% CI: 1.9 to 19.9 U) and collagen (mean difference: 9.8 U; 95% CI: 0.8 to 18.8 U) stimuli were higher among patients receiving placebo, whereas levels of platelet reactivity were similar with adenosine diphosphate and thrombin. ConclusionsAmong high-risk patients receiving drug-eluting stents, the antithrombotic potency of ticagrelor monotherapy is similar to that of ticagrelor plus ASA with respect to ex vivo blood thrombogenicity, whereas markers sensitive to cyclo-oxygenase-1 blockade are increased in the absence of ASA. (Platelet Substudy of the TWILIGHT Trial; NCT04001374).

Total Thrombus-Formation Analysis System (T-TAS): Clinical Application of Quantitative Analysis of Thrombus Formation in Cardiovascular Disease.

Various antithrombotic agents are clinically used to inhibit the cascade of arterial or venous thrombosis in cardiovascular diseases. Dual antiplatelet therapy with aspirin and P2Y12 inhibitors is prescribed in patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI). Direct oral anticoagulants (DOACs) are widely used for the prevention or treatment of thromboembolism in patients with atrial fibrillation (AF) and venous thromboembolism. However, there has been no definitive tool to simultaneously monitor the antithrombotic effects of these drugs. The Total Thrombus-Formation Analysis System (T-TAS), a microchip-based flow chamber system that mimics in vivo conditions for evaluating whole blood thrombogenicity, was developed for the quantitative analysis of thrombus formation in whole blood specimens. The utility of T-TAS has been evaluated in CAD patients treated with antiplatelet therapies. The T-TAS PL chip area under the flow pressure curve (AUC) accurately assesses primary hemostasis and is sensitive to the therapeutic effects of various antiplatelet therapies. In addition, low AUC results are a significant predictor of periprocedural bleeding events in CAD patients undergoing PCI. The T-TAS AR chip AUC result is useful for assessing the efficacy of DOACs and warfarin in AF patients undergoing catheter ablation, and it is also a potential independent predictor of periprocedural bleeding events and avoidance of thrombosis in patients having undergone total knee arthroplasty. In conclusion, T-TAS is a useful index for evaluating the total antithrombotic effects of combination antithrombotic agents in patients with various cardiovascular diseases.

Sulfenamide and Sulfonamide Derivatives of Metformin \u2013 A New Option to Improve Endothelial Function and Plasma Haemostasis

Type 2 diabetes mellitus (T2DM) is a multi-factorial disease which can cause multiple organ dysfunction, including that of the vascular endothelium. The aim of the present study was to evaluate the effects of metformin, and its sulfenamide and sulfonamide derivatives (compounds 1–8) on the selected markers of endothelial function and blood coagulation. The integrity of endothelial cells(ECs) was examined using the real-time cell electric impedance system. Tissue Factor(TF) production, the release of von Willebrand Factor (vWF) and tissue plasminogen activator(t-PA) from ECs were determined using immunoenzymatic assays, while the process of platelet thrombus formation using the Total Thrombus-Formation Analysis System. Sulfenamide with n-butyl alkyl chain(3) does not interfere with ECs integrity, and viability (nCI(24h) = 1.03 ± 0.03 vs. 1.06 ± 0.11 for control), but possesses anticoagulation properties manifested by prolonged platelet-dependent thrombus formation (Occlusion Time 370.3 ± 77.0 s vs. 286.7 ± 65.5 s for control) in semi-physiological conditions. Both p- and o-nitro-benzenesulfonamides (compounds7,8) exhibit anti-coagulant properties demonstrated by decreased vWF release and prolonged parameters of platelet thrombus formation and total blood thrombogenicity. In conclusion, chemical modification of metformin scaffold into sulfenamides or sulfonamides might be regarded as a good starting point for the design and synthesis of novel biguanide-based compounds with anticoagulant properties and valuable features regarding endothelial function.

Remarkable Improvement of Ejection Fraction in Response to Herbal Decoction Containing High-dose Astragalus Mongholicus: A Case Report

Dronedarone reduced the rate of stroke and transient ischemic attack in patients with paroxysmal atrial fibrillation (AF) in the ATHENA trial. This cannot be explained by its antiarrhythmic effect alone and may involve alternative mechanisms. This study aimed to investigate any direct effect of dronedarone on blood thrombogenicity, independent of its antiarrhythmic effects.Blood samples from patients with cardiovascular disease (n = 30) taking no anticoagulant or antiplatelet medication except aspirin were incubated with dronedarone's active metabolite (SR35021A) at 66 ng/ml (am-L) and 119 ng/ml (am-H), i.e., minimum and maximum mean Cmax reported after repeated 400 mg BID dosing. A third aliquot of blood was incubated with vehicle (Control). Antithrombotic effects of dronedarone were assessed using Coagulation Time (CT), Clot Formation Rate (CFR) and Maximum Clot Firmness (MCF) in ThromboElastoMetry and whole blood platelet aggregation in response to ADP, collagen and TRAP.Compared to Control, mean CT was prolonged by am-L and am-H (164 ± 25 s vs. 180 ± 22 and 182 ± 32 s, respectively, p<0.01 for both). Small but statistically significant reductions were observed in CFR (am-L and am-H) and MCF (am-H). Platelet aggregation induced by ADP and TRAP was also reduced (p<0.05 for both) by am-H.Dronedarone exerts direct anticoagulant and antiplatelet effects on human blood in vitro that are independent of its antiarrhythmic actions. This suggests the reductions in ischemic events reported with dronedarone may not be due to amelioration of AF itself. Additional clinical studies are required to further improve understanding of the mechanisms involved.

Impact of Menopausal Hormone Treatments on Intravascular Cellular Activation and Development of White Matter Hyperintensities in Healthy Postmenopausal Women

ObjectiveBlood thrombogenicity and vascular inflammation may influence development of white matter hyperintensities (WMH) in the brain. This study aimed to determine if menopausal hormone treatments (MHT) modified that association in recently menopausal women who were enrolled in the Kronos Early Estrogen Prevention Study (KEEPS) at Mayo Clinic.MethodsWomen (n=95) underwent MRI prior to and at 18, 36 and 48 months after randomization to either transdermal 17β‐estradiol (tE2, n=30), conjugated equine estrogen (oCEE, n=29) both with progesterone for 12 days per month or placebo pills and patch (PBO, n=36). Fasting blood was analyzed for a set of 14 activation markers of platelets and endothelial cells, inflammation, and thrombogenicity. Principal components (PC) analysis was used to reduce dimensionality of these markers, and the first 5 PC identified were then assessed for association with treatment and changes in WMH.ResultsWMH increased in all groups over the 48 months of treatment with greater increases in the oCEE compared to tE2 and PBO (P=0.015). The 5 PC explained 62% of the variation in cellular activation markers. A global test of these 5 PC revealed a borderline association with treatment group (P=0.059), with the PC reflecting total platelet count, platelet microaggregates and ATP secretion showing higher scores in the oCEE compared to the other groups (P=0.006). The change in WMH over the 48 months of MHT showed an overall association with the 5 PC (P=0.026), the most prominent of which was the first PC reflecting vascular inflammation by number of blood microveicles (MV) from activated monocytes and endothelial cells and MV positive for intercellular adhesion molecule 1 (P=0.001). There was no evidence that this association differed by MHT.ConclusionMarkers of blood thrombogenicity and inflammation may influence development of WMH in the brain but this relationship may be influenced by factors other than the type of MHT used in the KEEPS study.Support or Funding InformationNIH P50 AG44170This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.