Thromboxane B2 Research Articles

Efficacy and Safety of Text Messages Targeting Adherence to Cardiovascular Medications in Secondary Prevention: TXT2HEART Colombia Randomized Controlled Trial.

BackgroundAtherosclerotic cardiovascular disease (ASCVD) is the leading cause of mortality worldwide, with a prevalence of approximately 100 million patients. There is evidence that antiplatelet agents and antihypertensive medications could reduce the risk of new vascular events in this population; however, treatment adherence is very low. An SMS text messaging intervention was recently developed based on behavior change techniques to increase adherence to pharmacological treatment among patients with a history of ASCVD.ObjectiveThis study aims to evaluate the efficacy and safety of an SMS text messaging intervention to improve adherence to cardiovascular medications in patients with ASCVD.MethodsA randomized controlled clinical trial for patients with a prior diagnosis of cardiovascular events, such as acute myocardial infarction, unstable angina, cerebrovascular disease, or peripheral artery disease, in one center in Colombia was conducted. Patients randomized to the intervention arm were assigned to receive SMS text messages daily for the first 4 weeks, 5 SMS text messages on week 5, 3 SMS text messages each in weeks 6 and 7, and 1 SMS text message weekly from week 8 until week 52. In contrast, patients in the control arm received a monthly SMS text message reminding them of the next study appointment and the importance of the study, requesting information about changes in their phone number, and thanking them for participating in the study. The primary endpoint was the change in low-density lipoprotein cholesterol (LDL-C) levels, whereas the secondary endpoints were the changes in thromboxane B2 levels, heart rate, systolic and diastolic blood pressure, medication adherence, cardiac and noncardiac mortality, and hospitalization. Linear regression analyses and bivariate tests were performed.ResultsOf the 930 randomized patients, 805 (86.5%) completed follow-up and were analyzed for the primary endpoint. There was no evidence that the intervention changed the primary outcome (LDL-C levels; P=.41) or any of the secondary outcomes evaluated (all P>.05). There was also no evidence that the intervention was associated with adverse events.ConclusionsIn this study, there was no evidence that a behavior modification intervention delivered by SMS text messaging improved LDL-C levels, blood pressure levels, or adherence at 12 months. More research is needed to evaluate whether different SMS text messaging strategies, including personalized messages and different timings, are effective; future studies should include mixed methods to better understand why, for whom, and in which context (eg, health system or social environment) SMS text messaging interventions work (or not) to improve adherence in patients with ASCVD.Trial RegistrationClinicalTrials.gov NCT03098186; https://clinicaltrials.gov/ct2/show/NCT03098186International Registered Report Identifier (IRRID)RR2-10.1136/bmjopen-2018-028017

Increased Epoxyeicosatrienoic Acids and Hydroxyeicosatetraenoic Acids After Treatment of Iodide Intake Adjustment and 1,25-Dihydroxy-Vitamin D3 Supplementation in High Iodide Intake-Induced Hypothyroid Offspring Rats.

Aim: This study aimed to investigate the potential role of fatty acids in high iodide intake–induced hypothyroidism and its complications and also in the intervention of iodide intake adjustment and 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] supplementation.Methods: Pregnant rats were allocated to two groups, namely, normal iodide (NI, 7.5 μg/day) intake and 100 times higher-than-normal iodide (100 HI, 750 μg/day) intake. The offspring were continuously administered potassium iodide from weaning [i.e., postnatal day 21 (PN21)] to PN90. After PN90, the offspring were either administered iodide intake adjustment (7.5 μg/day) or 1,25(OH)2D3 supplementation (5 μg·kg−1·day−1), or both, for 4 weeks. Thyroid function tests (free triiodothyronine, free thyroxine, thyrotropin, thyroid peroxidase antibody, and thyroglobulin antibody), blood lipids (triglyceride, total cholesterol, free fatty acid, and low-density lipoprotein cholesterol), and vitamin D3 (VD3) levels were detected by ELISA. Cardiac function was measured by echocardiography. Blood pressure was measured using a non-invasive tail-cuff system. The serum fatty acids profile was analyzed by liquid chromatography–mass spectrometry.Results: In the offspring rats with continued 100 HI administration, the levels of 8,9-dihydroxyeicosatrienoic acid (8,9-DHET) and thromboxane B2 (TXB2) were decreased, while those of prostaglandin J2 (PGJ2), prostaglandin B2 (PGB2), 4-hydroxydocosahexaenoic acid (4-HDoHE), 7-HDoHE, 8-HDoHE, and 20-HDoHE were increased. Significant correlations were found between PGB2, 8,9-DHET, 7-HDoHE levels and thyroid dysfunction, between PGJ2, 20-HDoHE, PGB2, 8,9-DHET levels and cardiac dysfunction, between PGJ2, 20-HDoHE levels and hypertension, between 4-HDoHE, 8-HDoHE, TXB2 levels and dyslipidemia, and between PGB2 and decreased VD3 level. After the treatment of iodide intake adjustment and 1,25(OH)2D3 supplementation, the levels of 16-hydroxyeicosatetraenoic acids (16-HETE), 18-HETE, 5,6-epoxyeicosatrienoic acid (5,6-EET), 8,9-EET, 11,12-EET, 14,15-EET, PGE2, 5-oxo-ETE, and 15-oxo-ETE were increased. The significant associations between PGE2, 16-HETE, 18-HETE and improved thyroid function and also between 5,6-EET, 11,12-EET, 14,15-EET, 16-HETE, 15-oxo-ETE and attenuated dyslipidemia were detected.Conclusion: Increased levels of prostaglandins (PGs) and HDoHEs and decreased levels of 8,9-DHET and TXB2 might occur in the progression of cardiac dysfunction, hypertension, and dyslipidemia in high iodide intake–induced hypothyroidism. The increased levels of EETs and HETEs might help to ameliorate these complications after iodide intake adjustment and 1,25(OH)2D3 supplementation.

Cyclooxygenase-dependent mechanisms mediate in part the anti-dilatory effects of perivascular adipose tissue in uterine arteries from pregnant rats

Uterine perivascular adipose tissue (PVAT) contributes to uterine blood flow regulation in pregnancy, at least in part, due to its effects on uterine artery reactivity. We tested the hypothesis that uterine PVAT modulates the balance between the contribution of nitric oxide synthase (NOS)- and cyclooxygenase (COX)-dependent pathways to acetylcholine (ACh)-induced relaxation in isolated uterine arteries. Concentration-response curves to ACh (1 nM – 30 µM) were performed on uterine arteries from pregnant and non-pregnant rats. Arteries were exposed to Krebs-Henseleit solution (control) or PVAT-conditioned media (PVATmedia) in the presence of the following inhibitors: L-NAME (NOS inhibitor), indomethacin (COX inhibitor), SC560 (COX-1 inhibitor), NS398 (COX-2 inhibitor), SQ 29,548 (thromboxane receptor (TP) inhibitor). In arteries incubated with PVATmedia, the presence of indomethacin increased ACh-induced relaxation, reversing the anti-dilatory effect of PVATmedia. NOS inhibition reduced ACh-induced relaxation in uterine arteries from pregnant rats, and exposure to PVATmedia did not change this effect. Selective inhibition of COX-1 but not COX-2 suppressed relaxation responses to ACh in control arteries. The presence of PVATmedia abolished the effect of COX-1 inhibition. Incubation of uterine arteries from pregnant rats with PVATmedia increased production of thromboxane B2 (TxB2, p = 0.01) but thromboxane receptor (TP) inhibition did not affect the anti-dilatory properties of PVATmedia. In conclusion, inhibition of COX signaling suppressed the anti-dilatory effects of PVATmedia, while PVATmedia had no effect on the contribution of the NOS/NO pathway to ACh-induced relaxation in uterine arteries from pregnant rats, indicating that the anti-dilatory effects of uterine PVAT are mediated in part by COX-dependent mechanisms.

Levels of 15‐HETE and TXB2 in exhaled breath condensates as markers for diagnosis of childhood asthma and its therapeutic outcome

AbstractBackgroundDysregulation of eicosanoids is associated with asthma and a composite of oxylipins, including exhaled leukotriene B4 (LTB4), characterizes childhood asthma. While fractional exhaled nitric oxide (FeNO) has been used as the standard for monitoring steroid responsiveness, the potential utility of eicosanoids in monitoring the therapeutic outcomes remains unclear. We aimed to examine the levels of major eicosanoids representing different metabolic pathways in exhaled breath condensates (EBCs) of children with asthma during exacerbation and after treatment.MethodsLevels of 6 exhaled eicosanoid species in asthmatic children and healthy subjects were evaluated using ELISA.ResultsIn addition to those previously reported, including LTB4, the levels of exhaled 15‐hydroxyeicosatetraenoic acid (15‐HETE), but not thromboxane B2 (TXB2), showed significant difference between asthmatics (N = 318) and healthy controls (N = 97), particularly the severe group showed the lowest levels of exhaled 15‐HETE. Receiver operating characteristic (ROC) curve analyses revealed similar distinguishing power for the levels of 15‐HETE, FEV1 (forced expiratory volume in the first second), and FeNO, while the 15‐HETE/LTB4 ratio was significantly lower in subjects with asthma as compared to that of healthy controls (p < 0.0001). Analysis of asthmatics (N = 75) during exacerbation and convalescence showed significant improvement in lung function (FEV1, p < .001), but not FeNO, concomitant with significantly increased levels of 15‐HETE (p < .001) and reduced levels of TXB2 (p < .05) at convalescence, particularly for those who at the top 30% level during exacerbation. Further, decreased LTB4 and lipoxin A4 (LXA4) at convalescence were noted only in those at the top 30 percentile during exacerbation.ConclusionThe exhaled 15‐HETE was found to discriminate childhood asthma while decreased levels of exhaled TXB2 and increased levels of 15‐HETE were prominent at convalescence.

Urinary Thromboxane B2 and Lethal Prostate Cancer in African American Men.

Thromboxane A2 (TXA2) is a platelet- and cyclooxygenase-derived eicosanoid that has been linked to metastasis. We investigated the role of TXA2 in the development of lethal prostate cancer in African American (AA) and European American (EA) men. We measured urinary 11-dehydrothromboxane B2 (TXB2), a stable metabolite of TXA2, with mass spectrometry. Samples were obtained from 977 cases and 1022 controls at time of recruitment. We applied multivariable logistic and Cox regression modeling to examine associations of TXB2 with prostate cancer and patient survival. The median survival follow-up was 8.4 years, with 246 deaths among cases. Aspirin use was assessed with a questionnaire. Race was self-reported. Urinary TXB2 was inversely associated with aspirin use. High (>median) TXB2 was associated with prostate cancer in AA (adjusted odds ratio [OR] = 1.50, 95% confidence interval [CI] = 1.13 to 2.00) but not EA men (OR = 1.07, 95% CI = 0.82 to 1.40), suggesting upregulated TXA2 synthesis in AA men with prostate cancer. High TXB2 was positively associated with metastatic prostate cancer (OR = 2.60, 95% CI = 1.08 to 6.28) compared with low (≤median) TXB2. Furthermore, high TXB2 was also associated with all-cause (adjusted hazard ratio = 1.59, 95% CI = 1.06 to 2.40) and prostate cancer-specific mortality (hazard ratio = 4.74, 95% CI = 1.62 to 13.88) in AA men only. We report a distinct association of TXB2 with prostate cancer outcomes in AA men. In this high-risk group of men, upregulation of TXA2 synthesis may promote metastasis and lethal disease. Our observation identifies a potential benefit of aspirin in preventing lethal prostate cancer through inhibition of TXA2 synthesis.

Quantitative profiling of inflammatory and pro-resolving lipid mediators in human adolescents and mouse plasma using UHPLC-MS/MS.

Lipid mediators are bioactive lipids which help regulate inflammation. We aimed to develop an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to quantify 58 pro-inflammatory and pro-resolving lipid mediators in plasma, determine preliminary reference ranges for adolescents, and investigate how total parenteral nutrition (TPN) containing omega-3 polyunsaturated fatty acid (n-3 PUFA) or n-6 PUFA based lipid emulsions influence lipid mediator concentrations in plasma. Lipid mediators were extracted from plasma using SPE and measured using UHPLC-MS/MS. EDTA plasma was collected from healthy adolescents between 13 and 17 years of age to determine preliminary reference ranges and from mice given intravenous TPN for seven days containing either an n-3 PUFA or n-6 PUFA based lipid emulsion. We successfully quantified 43 lipid mediators in human plasma with good precision and recovery including several leukotrienes, prostaglandins, resolvins, protectins, maresins, and lipoxins. We found that the addition of methanol to human plasma after blood separation reduces post blood draw increases in 12-hydroxyeicosatetraenoic acid (12-HETE), 12-hydroxyeicosapentaenoic acid (12-HEPE), 12S-hydroxyeicosatrienoic acid (12S-HETrE), 14-hydroxydocosahexaenoic acid (14-HDHA) and thromboxane B2 (TXB2). Compared to the n-6 PUFA based TPN, the n-3 PUFA based TPN increased specialized pro-resolving mediators such as maresin 1 (MaR1), MaR2, protectin D1 (PD1), PDX, and resolvin D5 (RvD5), and decreased inflammatory lipid mediators such as leukotriene B4 (LTB4) and prostaglandin D2 (PGD2). Our method provides an accurate and sensitive quantification of 58 lipid mediators from plasma samples, which we used to establish a preliminary reference range for lipid mediators in plasma samples of adolescents; and to show that n-3 PUFA, compared to n-6 PUFA rich TPN, leads to a less inflammatory lipid mediator profile in mice.

Proprotein Convertase Subtilisin Kexin Type 9 Inhibitors Reduce Platelet Activation Modulating ox-LDL Pathways.

Background: Proprotein convertase subtilisin kexin type 9 inhibitors (PCSK9i) lower LDL-cholesterol and slow atherosclerosis preventing cardiovascular events. While it is known that circulating PCSK9 enhances platelet activation (PA) and that PCSK9i reduce it, the underlying mechanism is not still clarified. Methods: In a multicenter before–after study in 80 heterozygous familial hypercholesterolemia (HeFH) patients on treatment with maximum tolerated statin dose ± ezetimibe, PA, soluble-NOX2-derived peptide (sNOX2-dp), and oxidized-LDL (ox-LDL) were measured before and after six months of PCSK9i treatment. In vitro study investigates the effects of plasma from HeFH patients before and after PCK9i on PA in washed platelets (wPLTs) from healthy subjects. Results: Compared to baseline, PCSK9i reduced the serum levels of LDL-c, ox-LDL, Thromboxane (Tx) B2, sNOX2-dp, and PCSK9 (p < 0.001). The decrease of TxB2 correlates with that of ox-LDL, while ox-LDL reduction correlated with PCSK9 and sNOX2-dp delta. In vitro study demonstrated that wPLTs resuspended in plasma from HeFH after PCSK9i treatment induced lower PA and sNOX2-dp release than those obtained using plasma before PCSK9i treatment. This reduction was vanished by adding ox-LDL. ox-LDL-induced PA was blunted by CD36, LOX1, and NOX2 inhibition. Conclusions: PCSK9i treatment reduces PA modulating NOX2 activity and in turn ox-LDL formation in HeFH patients.

Abstract 34: High urinary thromboxane B2 associates with lethal prostate cancer in African American men and inversely correlates with aspirin use

Abstract Background: Systemic low-grade inflammation is a candidate risk factor for prostate cancer (PC) in African American (AA) men, potentially contributing to lethal PC development. We previously reported that regular aspirin use is associated with a decreased risk of advanced stage disease and disease recurrence in AA patients with PC. The cancer-preventive benefits of aspirin have been attributed to inhibition of the cyclooxygenase (COX) pathway. Thromboxane A2 (TXA2) is an eicosanoid produced by the COX1 enzyme in platelets. Aspirin can inhibit metastasis by inhibiting COX1 activity and TXA2 synthesis. Hence, we assessed the role of TXA2 in the development of lethal PC. Because TXA2 is unstable, we measured its corresponding primary metabolite, urinary thromboxane B2 (TXB2), to examine the relationship of TXA2 with PC. Method: TXB2 was measured in cases (977) and controls (1022) from the NCI-MD PC Case-Control study using a mass-spectrometry-based assay. TXB2 levels were modeled into low (≤median) and high (&amp;gt;median) levels. We calculated risk factor-adjusted odds ratios (ORs) and 95% confidence intervals (CI) using unconditional logistic regression, adjusted hazard ratios (HR) using Cox regression and sub hazard ratios (SHR) using the Fine-Gray model. Results: We observed increased TXB2 levels in cases and an inverse relationship between levels of TXB2 and aspirin use in both cases and controls. For cases who used aspirin, the odds of having high TXB2 were reduced when compared to non-users (OR 0.46 95%CI, 0.34-0.61). This observation remained significant when stratified by race/ethnicity (AA: OR 0.36 95%CI, 0.23-0.54; EA: OR 0.58 95%CI, 0.38-0.88), indicating significant inhibition of TXB2 formation by aspirin, most notably in AA men. Further analysis showed that high TXB2 is associated with a PC case status in AA men (OR 1.44 95%CI, 1.08-1.93) but not EA men (OR 1.07 95%CI, 0.83-1.93), indicating increased TXA2 synthesis in AA men with PC compared to AA men without the disease. Also, men with high TXB2 were more likely to be diagnosed with metastasis compared to men with low TXB2 (OR 4.27 95%CI, 1.48-12.29), indicating more aggressive disease for cases with high TXB2. Furthermore, high TXB2 was associated with all-cause mortality (HR 1.56 95%CI, 1.05-2.33) and PC mortality (HR 4.02 95%CI, 1.46-11.07; SHR 2.89 95%CI, 1.03-8.11) in AA men only. Our findings indicate a distinct association between TXA2 and PC outcomes in AA men. Conclusion: Aspirin use inversely associates with high TXB2. This is of clinical interest as we report that increased TXB2 associates with PC in AA men, with aggressive PC, and with PC death which disproportionally affects AA men. This is consistent with our previous findings that aspirin may reduce lethal PC in AA men and highlights the potential benefit of aspirin for prevention of lethal PC in this high-risk group of men through inhibition of TXA2 synthesis. Citation Format: Maeve Bailey-Whyte, Ginger Milne, Tsion Z. Minas, Tiffany H. Dorsey, Wei Tang, Cheryl J. Smith, Michael B. Cook, Clayton Yates, Stefan Ambs. High urinary thromboxane B2 associates with lethal prostate cancer in African American men and inversely correlates with aspirin use [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 34.

Lower Antiplatelet Effect of Aspirin in Essential Thrombocythemia than in Coronary Artery Disease.

Background Patients with essential thrombocythemia (ET) and coronary artery disease (CAD) have increased risk of thromboembolic complications. In addition, a reduced antiplatelet effect of aspirin has been demonstrated in both patient groups. As ET is a platelet disorder, platelets may be more important for the thromboembolic risk in ET than in CAD. We aimed to investigate the antiplatelet effect of aspirin and platelet turnover in ET versus CAD patients. Methods We included 48 ET patients and an age-matched group of 48 CAD patients. The effect of aspirin was evaluated by thromboxane B 2 (TXB 2 ) levels and platelet aggregation. Platelet turnover was assessed by immature platelet count (IPC) and immature platelet fraction (IPF). Results ET patients had reduced effect of aspirin compared with CAD patients, demonstrated by significantly higher TXB 2 levels (median of differences = 22.3 ng/mL, p < 0.0001) and platelet aggregation (median of differences = 131.0 AU*min, p = 0.0003). Furthermore, ET patients had significantly higher IPC ( p < 0.0001) and IPF ( p = 0.0004) than CAD patients. Conclusion ET patients have lower 24-hour antiplatelet effect of aspirin than CAD patients. This may be explained by an increased platelet production and turnover counteracting the antiplatelet effect of aspirin. These findings strengthen the rationale for exploring novel antiplatelet regimens in ET patients to reduce the risk of cardiovascular events.

A Portable System for Processing Donated Whole Blood into High Quality Components without Centrifugation

Introduction: Centrifugation is the cornerstone of blood processing because it has been the only technology capable of separating large volumes of whole blood (WB) into components for storage under optimal conditions in a reasonable amount of time. However, the logistical complications and potential cellular damage associated with centrifugation-based manufacturing of blood products are well documented. In this study, we present a new dual-stage, passive separation system for processing WB into components, which does not require costly or complex machinery, and can be used on-site by minimally-trained personnel immediately following blood donation. This approach consists of two passive blood-processing modules, neither of which requires electricity: (i) a blood-bag compression apparatus designed to maximize the speed and efficiency of passive RBC sedimentation for separating RBCs and platelet-rich plasma (PRP) from WB at normal gravity (i.e. 1×g), and (ii) a flow-through microfluidic concentrator for continuous high-throughput enrichment of platelets from the PRP fraction, to produce platelet concentrate (PC) and platelet-poor plasma (PPP). The ability of this technology to produce high-quality blood components quickly without the use of a centrifuge was demonstrated.Materials and Methods: Freshly-donated units (~500mL) of whole blood (WB) were randomly selected (under an IRB approved protocol) from blood donations by healthy donors who met AABB/FDA eligibility criteria. The WB units (n = 6) were divided into two equal parts, with one half processed by the conventional centrifugation technique (‘PRP method,‘ control arm), and the other half with our new portable blood separation system (test arm). Both separation procedures were performed concurrently, within 4 hours of donation. The initial quality of blood products (RBCs, platelets and plasma) generated by the two approaches were compared using an extensive panel of hematological parameters, including hematocrit, mean corpuscular volume, platelet count, mean platelet volume, white blood cell count, RBC and platelet phosphatidylserine (PS) exposure, platelet P-selectin expression, total free protein, free hemoglobin (Hb), % hemolysis, RBC deformability, pH, K+, Na+, glucose, lactate, ATP, 2,3-diphosphoglyceric acid concentration (2,3-DPG), platelet aggregability (agonists: thrombin receptor agonist peptide, adenosine diphosphate, collagen), factors VIII and XI, soluble CD40-ligand (sCD40L), and thromboxane B2 (TxB2).Results and Discussion: To perform separation using our new portable separation system, 250mL (‘half-unit‘) of WB was placed in a 1L sedimentation bag between two plates of a custom-made compression apparatus at a slight incline (~10°) to allow natural sedimentation of WB into PRP and RBCs at unit gravity. After 150 minutes of sedimentation, the supernatant PRP was expressed from the sedimentation bag through the high-throughput microfluidic platelet concentrator at ~3.2 mL/min to process PRP into PC and PPP. Following PRP expression, the sedimented RBCs were mixed with AS-3 and leukoreduced in the same manner as RBCs produced via centrifugation. The entire separation process for a half-unit of WB was completed within ~3 hours. Comparison of nearly all RBC parameters showed no significant differences between the two separation approaches, although the portable system generated RBC units with a slight, statistically significant improvement in 2,3-DPG (portable system: 15.8 ± 1.2 µmol/g of Hb; centrifugation: 15.3 ± 1.2 µmol/g of Hb; p < 0.05). Importantly, key markers of platelet damage were significantly and meaningfully reduced in PC units generated using the portable, centrifuge-free system: platelet activation (assessed via P-selectin expression) was less than half of that for PC units produced via centrifugation (portable system: 5.2 ± 2.1%; centrifugation: 12.2 ± 3.6%; p < 0.01), and the release of pro-inflammatory mediators (sCD40L, TxB2) was also significantly lower in PC units produced with the portable system than via centrifugation (p < 0.01).Conclusion: This study demonstrated that a simple, portable, passive system for separating donated blood into components could be a viable alternative to centrifugation - particularly for applications in remote or resource-limited settings, or for patients requiring highly functional and undamaged platelets. [Display omitted] DisclosuresGifford:Halcyon Biomedical Incorporated: Employment, Equity Ownership. Shevkoplyas:New Health Sciences, Inc.: Consultancy, Research Funding; Halcyon Biomedical Incorporated: Employment, Equity Ownership, Patents & Royalties: U.S. Patent Appl. 61/929,357, Research Funding.

Poor Responsiveness to Low-Dose Aspirin Contributes to Persistent In Vivo Platelet Activation in Polycythemia Vera

▪Introduction . Polycythemia Vera (PV) is a myeloproliferative neoplasm characterized by peripheral erythrocytosis, increased thrombotic risk affecting morbidity and mortality. Low-dose aspirin once-daily (od) is currently recommended for cardiovascular prevention in PV. However, it has been recently suggested that aspirin should be used at 100 mg twice-daily (bid) in PV patients at high cardiovascular risk (JAK2V617F allelic burden, age >60 years) on the assumption of a shorter lasting antiplatelet effect, similarly to essential thrombocythemia. However, pharmacological and clinical data supporting the need for a bid ASA regimen in PV are missing.Methods . We studied the platelet responsiveness to standard aspirin (100 mg od) in PV patients, assessed at the end of the 24-h dosing interval. Patients were diagnosed according to the WHO 2008 criteria, were all on od low-dose aspirin and underwent a run-in phase (7-10 days) where aspirin tablets were always ingested at breakfast. Routine hematochemistry, genotype and allelic burden, clinical characteristics and history, medications were recorded. Serum thromboxane B2 (sTXB2) was measured as ex vivo biomarker of aspirin pharmacodynamics, urinary 11-deidro-TXB2 (TXM) as in vivo index of platelet activation, the major urinary prostacyclin metabolite, 2,3 dinor 6-keto-PGF1α (PGIM), the urinary isoprostane 8-iso-PGF2α and plasma salicylic acid esterase activity.Results . Forty-nine patients (67±10 years, 16 females) on aspirin for ≥1 month gave their informed consent; aspirin compliance and non-steroidal anti-inflammatory drug intake were checked by phone calls and patient's interview on the day of the visit. Nine patients were on phlebotomy only, while the remaining patients were on phlebotomy and hydroxyurea to keep the hematocrit <45%. Average hematologic values were: hematocrit 43.8±3%; erythrocytes 5.3±1.3x106/µL; leukocytes 9.1±4.3x103/µL, platelets 359±165x103/µL, immature platelets 11.8±7.4x103/µL. The median sTXB2 value was 8.6 [2-50] ng/ml, urinary TXM 509 [205-3428] pg/mg creatinine, 8-iso-PGF2α 768 [234-2104] pg/mg creatinine, PGIM 172 [120-275] pg/mg creatinine, plasma esterase activity 53 [47-60] µmol/L salycilic acid/min. Overall, sTXB2 significantly (p<0.01) correlated with immature platelets (rho=0.46), erythrocyte count (rho=0.41), leukocytes (rho=0.39). Patients were then divided according to sTXB2 tertiles, and patients in the lowest tertile showed sTXB2 levels within the expected range (3.4 [2.4-4.2] ng/ml, Figure). The patients in the upper tertile of sTXB2 levels (19.8 [15.3-40.9] ng/ml) were characterized by significantly (p<0.05) higher erythrocyte counts, total platelet counts, and immature platelets (p=0.05), while age, JAK2V617F allelic burden, leukocytes, hematocrit, hemoglobin, and sex distribution were comparable across tertiles. Urinary TXM significantly (p<0.05) correlated with sTXB2 (rho=0.39 and Figure), disease duration (rho=0.33), and leukocytes (rho=0.33). By multivariable analysis, only sTXB2 (p=0.009) positively predicted urinary TXM excretion. Urinary PGIM correlated with 8-iso-PGF2α excretion but not with TXM. Plasma esterase activity correlated with hemoglobin levels (rho=0.33, p=0.04), but not with the hematocrit, erythrocyte count, urinary TXM or sTXB2. JAK2V617F burden was significantly associated with polymorphonucleate count (rho=0.65), hemoglobin (rho=-0.49), and male sex (rho=0.41) while it was unrelated to previous thrombosis, sTXB2, urinary TXM and PGIM. By multivariable analysis JAK2V617F allelic burden predicted leukocyte counts only.Conclusions . A fraction of PV patients characterized by high erythrocyte, platelet and immature platelet count have a reduced response to a standard regimen of low-dose aspirin, which may contribute to persistently enhanced in vivo platelet activation. An improved antiplatelet regimen should be tested in these patients. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Impaired Clinical Efficacy of Aspirin in Hypoalbuminemic Patients With Diabetes Mellitus

Objective: To investigate the impact of albumin levels on the aspirin efficacy, since aspirin inhibits platelet aggregation (PA) by cyclooxygenase one irreversible acetylation that is less effective in patients with type 2 diabetes mellitus (T2DM). Patients and Methods: A total of 612 aspirin (100 mg/day)-treated T2DM patients were followed-up for 54.4 ± 7.3 months. The primary endpoint, a composite of cardiovascular events (CVEs) including CV death, myocardial infarction, ischemic stroke and coronary revascularization, was analysed according to baseline values of serum albumin (≥ or < 3.5 g/dL). Serum thromboxane (Tx)B2 was also measured. Results: 250 (40.8%) patients had serum albumin < 3.5 g/dL; these patients were overweight and had higher values of fibrinogen (p = 0.009), high sensitivity C-reactive protein (p = 0.001) and fasting plasma glucose (p < 0.0001) compared to those with albumin ≥ 3.5 g/dL. During follow-up, 86 CVEs were recorded, 49 and 37 in patients with serum albumin < or ≥3.5 g/dL, respectively (p = 0.001). At multivariable Cox regression analysis, serum albumin < 3.5 g/dL (hazard ratio [HR] 1.887, 95% confidence interval [CI] 1.136–3.135, p = 0.014), age (HR 1.552 for every 10 years, 95%CI 1.157–2.081, p = 0.003), fasting plasma glucose (HR 1.063, 95%CI 1.022–1.105, p = 0.002) and beta-blocker use (HR 0.440, 95%CI 0.270–0.717, p = 0.001) were associated to CVEs. Serum TxB2 levels (n = 377) were 0.32 ± 0.12 and 0.24 ± 0.12 ng/ml in patients with albumin < or ≥ 3.5 g/dL, respectively (p < 0.001). Conclusion: In T2DM patients, the efficacy of aspirin varies according to albumin levels. Hypoalbuminemia associated with impaired TxB2 inhibition and an increased risk of long-term CVEs.

Homocysteine Causes Endothelial Dysfunction via Inflammatory Factor-Mediated Activation of Epithelial Sodium Channel (ENaC).

BackgroundHyperhomocysteinemia (HHcy) causes cardiovascular diseases via regulating inflammatory responses. We investigated whether and how the epithelial sodium channel (ENaC), a recently identified ion channel in endothelial cells, plays a role in HHcy-induced endothelial dysfunction.MethodsCell-attached patch-clamp recording in acute split-open aortic endothelial cells, western blot, confocal imaging, and wire myograph combined with pharmacological approaches were used to determine whether HHcy-mediated inflammatory signaling leads to endothelial dysfunction via stimulating ENaC.ResultsThe data showed that 4 weeks after L-methionine diet the levels of plasma Hcy were significantly increased and the ENaC was dramatically activated in mouse aortic endothelial cells. Administration of benzamil, a specific ENaC blocker, ameliorated L-methionine diet-induced impairment of endothelium-dependent relaxation (EDR) and reversed Hcy-induced increase in ENaC activity. Pharmacological inhibition of NADPH oxidase, reactive oxygen species (ROS), cyclooxygenase-2 (COX-2)/thromboxane B2 (TXB2), or serum/glucocorticoid regulated kinase 1 (SGK1) effectively attenuated both the Hcy-induced activation of endothelial ENaC and impairment of EDR. Our in vitro data showed that both NADPH oxidase inhibitor and an ROS scavenger reversed Hcy-induced increase in COX-2 expression in human umbilical vein endothelial cells (HUVECs). Moreover, Hcy-induced increase in expression levels of SGK-1, phosphorylated-SGK-1, and phosphorylated neural precursor cell-expressed developmentally downregulated protein 4-2 (p-Nedd4-2) in HUVECs were significantly blunted by a COX-2 inhibitor.ConclusionWe show that Hcy activates endothelial ENaC and subsequently impairs EDR of mouse aorta, via ROS/COX-2-dependent activation of SGK-1/Nedd4-2 signaling. Our study provides a rational that blockade of the endothelial ENaC could be potential method to prevent and/or to treat Hcy-induced cardiovascular disease.

Differential effects of heat-not-burn and conventional cigarettes on coronary flow, myocardial and vascular function

We compared the effects of Heat-not-Burn cigarette (HNBC) to those of tobacco cigarette (Tcig), on myocardial, coronary and arterial function as well as on oxidative stress and platelet activation in 75 smokers. In the acute study, 50 smokers were randomised into smoking a single Tcig or a HNBC and after 60 min were crossed-over to the alternate smoking. For chronic phase, 50 smokers were switched to HNBC and were compared with an external group of 25 Tcig smokers before and after 1 month. Exhaled carbon monoxide (CO), pulse wave velocity (PWV), malondialdehyde (MDA) and thromboxane B2 (TxB2) were assessed in the acute and chronic study. Global longitudinal strain (GLS), myocardial work index (GWI), wasted myocardial work (GWW), coronary flow reserve (CFR), total arterial compliance (TAC) and flow-mediated dilation (FMD) were assessed in the chronic study. Acute HNBC smoking caused a smaller increase of PWV than Tcig (change 1.1 vs 0.54 m/s, p < 0.05) without change in CO and biomarkers in contrast to Tcig. Compared to Tcig, switching to HNBC for 1-month improved CO, FMD, CFR, TAC, GLS, GWW, MDA, TxB2 (differences 10.42 ppm, 4.3%, 0.98, 1.8 mL/mmHg, 2.35%, 19.72 mmHg%, 0.38 nmol/L and 45 pg/mL respectively, p < 0.05). HNBCs exert a less detrimental effect on vascular and cardiac function than tobacco cigarettes.Trial registration Registered on https://clinicaltrials.gov/ (NCT03452124, 02/03/2018).

Local shifts in inflammatory and resolving lipid mediators in response to tendon overuse.

Tendon inflammation has been implicated in both adaptive connective tissue remodeling and overuse-induced tendinopathy. Lipid mediators control both the initiation and resolution of inflammation, but their roles within tendon are largely unknown. Here, we profiled local shifts in intratendinous lipid mediators via liquid chromatography-tandem mass spectrometry in response to synergist ablation-induced plantaris tendon overuse. Sixty-four individual lipid mediators were detected in homogenates of plantaris tendons from ambulatory control rats. This included many bioactive metabolites of the cyclooxygenase (COX), lipoxygenase (LOX), and epoxygenase (CYP) pathways. Synergist ablation induced a robust inflammatory response at day 3 post-surgery characterized by epitenon infiltration of polymorphonuclear leukocytes and monocytes/macrophages (MΦ), heightened expression of inflammation-related genes, and increased intratendinous concentrations of the pro-inflammatory eicosanoids thromboxane B2 and prostaglandin E2 . By day 7, MΦ became the predominant myeloid cell type in tendon and there were further delayed increases in other COX metabolites including prostaglandins D2 , F2α , and I2 . Specialized pro-resolving mediators including protectin D1, resolvin D2 and D6, as well as related pathway markers of D-resolvins (17-hydroxy-docosahexaenoic acid), E-resolvins (18-hydroxy-eicosapentaenoic acid), and lipoxins (15-hydroxy-eicosatetraenoic acid) were also increased locally in response to tendon overuse, as were anti-inflammatory fatty acid epoxides of the CYP pathway (eg, epoxy-eicosatrienoic acids). Nevertheless, intratendinous prostaglandins remained markedly increased even following 28 days of tendon overuse together with a lingering MΦ presence. These data reveal a delayed and prolonged local inflammatory response to tendon overuse characterized by an overwhelming predominance of pro-inflammatory eicosanoids and a relative lack of specialized pro-resolving lipid mediators.

Network Pharmacology Prediction and Pharmacological Verification Mechanism of Yeju Jiangya Decoction on Hypertension.

Background Yeju Jiangya decoction (CIF) is an herbal formula from traditional Chinese medicine (TCM) for the treatment of hypertension. Materials and Methods Based on the analysis of network pharmacology, combined with in animal experiments, the network pharmacology was used to explore the potential proteins and mechanisms of CIF against hypertension. The bioactive compounds of CIF were screened by using the platform, and the targets of hypertension and CIF were collected. Then, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction network (PPI) core targets were carried out, and the useful proteins were found by molecular docking technology. Finally, we used N-nitro-L-arginine (L-NNA) induced hypertension model rats to confirm the effect and mechanism of CIF on hypertension. Results 14 bioactive compounds of CIF passed the virtual screening criteria, and 178 overlapping targets were identified as core targets of CIF against hypertension. The CIF-related target network with 178 nodes and 344 edges is constructed. The topological results show that quercetin and luteolin are the key components in the network. The key targets NOS3 (nitric oxide synthase 3) and NOS2 (nitric oxide synthase 2) were screened by the protein-protein interaction network. The analysis of target protein pathway enrichment showed that the accumulation pathway is related to the vascular structure of CIF regulation of hypertension. Further verification based on molecular docking results showed that NOS3 had the good binding ability with quercetin and luteolin. On the other hand, NOS3 has an important relationship with the composition of blood vessels. Furthermore, the animal experiment indicated that after the L-NNA-induced hypertension rat model was established, CIF intervention was given by gavage for 3 weeks, and it can decrease serum concentrations of endothelin-1 (ET-1) and thromboxane B2 (TXB2), increase the expression of nitric oxide (NO) and prostacyclin 2 (PGI2), and improve renal, cardiac, and aortic lesions. At the same time, it can reduce blood pressure and shorten vertigo time. Western blot (WB) and immunohistochemistry (IHC) analyses indicated that CIF may downregulate the expression of NOS3, guanylyl cyclase-alpha 1 (GC-α1), guanylyl cyclase-alpha 2 (GC-α2), and protein kinase CGMP-dependent 1 (PRKG1). These results suggest that CIF may play an antihypertensive role by inhibiting the activation of the NOS3/PRKG1 pathway. Conclusions The results of this study indicate that CIF has the ability to improve target organs, protect endothelial function, and reduce blood pressure and that CIF might be a potential therapeutic drug for the prevention of hypertension. It provides new insight into hypertension and the potential biological basis and mechanism for CIF clinical research.

Relationship between the changes in thromboxane B2, 6-keto-prostaglandin Fla, and blood glucose levels and progressive ischemic stroke.

Progressive ischemic stroke is a common cerebrovascular disease with high morbidity. This study aimed to investigate the relationship between changes of Thromboxane B2 (TXB2), 6-keto-prostaglandin Fla (6-k-PGFla), and blood glucose (BG) levels with progressive ischemic stroke. A total of 106 patients with progressive ischemic stroke admitted to our hospital from December 2016 to December 2018 were recruited as the observation group, and 110 patients who received physical examination in our hospital during the same period were selected as the control group. The levels of TXB2, 6-k-PGFla, and BG in different groups were compared, the related risk factors affecting the prognosis of patients with progressive ischemic stroke were analyzed, and the receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of TXB2, 6-k-PGFla, and BG for the prognostic mortality of patients with progressive ischemic stroke. The levels of TXB2, 6-k-PGFla, and BG in the observation group were significantly higher than those in the control group (P<0.05). The prognostic mortality of participants with abnormally increased expression of TXB2, 6-k-PGFla, and BG was significantly higher than that of patients with normal expression of TXB2, 6-k-PGFla, and BG (P<0.05). Hypertension, diabetes, collateral circulatory disorders, hyperlipidemia, TXB2 (abnormal increase), 6-k-PGFla (abnormal increase), and BG (abnormal increase) were risk factors affecting the prognosis of patients with progressive ischemic stroke (P<0.05). The area under the curve (AUC) of the ROC curve showed that TXB2, 6-k-PGFla, BG, and the combination of them were 0.846, 0.893, 0.835, and 0.971, respectively, showing that the AUC of the combination of them was the largest. Hypertension, diabetes, collateral circulatory disorders, hyperlipidemia, TXB2 (abnormal increase), 6-k-PGFla (abnormal increase), and BG (abnormal increase) are risk factors affecting the prognosis of patients with progressive ischemic stroke. The combined detection of the 3 indicators showed high sensitivity and specificity in evaluating the prognostic mortality of patients with progressive ischemic stroke, indicating that clinicians might improve the early diagnosis rate of progressive ischemic stroke by combining the detection of TXB2, 6-k-PGFla, and BG to predict the prognosis of patients.

Anti-hyperlipidemic effects of the compound Danshen tablet: roles of antioxidation, anti-inflammation, anticoagulation, and anti-apoptosis

BackgroundHyperlipidemia could cause some serious harm to human health diseases, such as atherosclerosis, coronary heart disease. This study sought to investigate the effects of the compound Danshen tablet (CDT) on hyperlipidemia induced by a high-fat diet in ApoE−/− mice and related antioxidation, anti-inflammation, anticoagulation, and anti-apoptosis mechanisms.MethodsThe control group (Group 1) comprised 15 male C57BL/6N mice, and the other 5 groups (Groups 2–6) comprised 75 male ApoE−/− mice. These 75 mice were randomly divided into 1 of the following 5 groups: Group 2, a model group; Groups 3–5, the CDT groups, each of which was administered 375, 750, or 1,500 mg/kg of CDT; and Group 6, an atorvastatin group, which was administered 5.2 mg/kg of atorvastatin. All the mice were fed a high-fat diet for 16 weeks and intragastrically administered with CDT or atorvastatin once a day according to their body weight. After 16 weeks, serum was collected, the aorta was isolated, and blood lipid levels were detected. An enzyme-linked immunosorbent assay was used to detect the serum levels of 4-hydroxynonenal (4-HNE), 8-hydroxy-2'-deoxyguanosine (8-OHdG), intercellular adhesion molecule 1 (ICAM-1), monocyte chemoattractant protein 1 (MCP-1), thromboxane B2 (TXB2), tissue plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1). The thickness of the aortic wall was measured by ultrasonography. Atherosclerotic plaque and endothelial cell apoptosis in the aortic root were evaluated using oil red O staining and terminal dUTP nick-end labeling (TUNEL) assays, respectively.ResultsA comparison of mice in the CDT group and mice in the model group showed that CDT significantly inhibited mice’s weight gain. CDT reduced the levels of the inflammatory factor ICAM-1 and the oxidative damage molecule 4-HNE. In the coagulation system, CDT significantly increased tPA levels and reduced TXB2 and PAI-1 levels. Ultrasonography showed that CDT increased the thickness of the aortic wall. The oil red O staining results revealed that CDT significantly ameliorated lipid accumulation in the aortic valve. TUNEL assays indicated that CDT reduced the number of TUNEL-positive cells in the aortic valve.ConclusionsCDT has a certain protective effect on hyperlipidemia. The mechanism of CDT may be related to antioxidation, anti-inflammation, anticoagulation, and anti-apoptosis.

Celecoxib Alleviates Radiation-Induced Brain Injury in Rats by Maintaining the Integrity of Blood-Brain Barrier.

The underlying mechanisms of radiation-induced brain injury are poorly understood, although COX-2 inhibitors have been shown to reduce brain injury after irradiation. In the present study, the effect of celecoxib (a selective COX-2 inhibitor) pretreatment on radiation-induced injury to rat brain was studied by means of histopathological staining, evaluation of integrity of blood-brain barrier and detection of the expressions of inflammation-associated genes. The protective effect of celecoxib on human brain microvascular endothelial cells (HBMECs) against irradiation was examined and the potential mechanisms were explored. Colony formation assay and apoptosis assay were undertaken to evaluate the effect of celecoxib on the radiosensitivity of the HBMECs. ELISA was used to measure 6-keto-prostaglandin F1α (6-keto-PGF1α) and thromboxane B2 (TXB2) secretion. Western blot was employed to examine apoptosis-related proteins expressions. It was found that celecoxib protected rat from radiation-induced brain injury by maintaining the integrity of the blood-brain barrier and reducing inflammation in rat brain tissues. In addition, celecoxib showed a significant protective effect on HBMECs against irradiation, which involves inhibited apoptosis and decreased TXB2/6-keto-PGF1α ratio in brain vascular endothelial cells. In conclusion, celecoxib could alleviate radiation-induced brain injury in rats, which may be partially due to the protective effect on brain vascular endothelial cells from radiation-induced apoptosis.

The prevalence and associated factors of aspirin resistance among prophylactic aspirin users

Background. Aspirin is an antiplatelet used for the secondary prevention after vascular events. It is also suggested for the primary prevention of vascular events in high risk people, however, despite using standard prophylactic doses, aspirin resistance may result in therapeutic failure and arterial thrombosis. Since the prevalence of aspirin resistance and its associated factors were heterogeneous in different studies, this study was conducted to determine the prevalence and associated factors of aspirin resistance in an Iranian population under aspirin for primary prevention of vascular events. Methods. 264 patients without documented vascular disease with 80 mg daily aspirin consumption for at least one month enrolled in this cross-sectional study. Aspirin resistance was assessed by the measurement of thromboxane B2 in the urine samples using the enzyme-linked immunosorbent assay method. Aspirin resistance was defined as a urine level of thromboxane B2 ≥ 1700 ng/dl. Results. The prevalence of aspirin resistance in this study was 9.8%. Age (OR = 0.935, 95% CI: 0.880-0.993, P = 0.028) and geographical regions (OR = 0.117, 95% CI: 0.014-0.958, P = 0.045) showed independent correlation with aspirin resistance. No significant association observed between aspirin resistance and gender, diabetes mellitus, hypertension, hyperlipidemia, smoking, duration of aspirin use, body mass index, and drug history. Conclusions. Despite the standard daily dose of aspirin for primary prevention of vascular events, some of our patients exhibited aspirin resistance that was directly related to a higher age and geographical region. More studies are required to clarify the beneficial role of aspirin resistance test before planning a preventive strategy in high risk individuals.