Thromboxane B2 Concentrations Research Articles

Vascular Inflammatory Markers as Predictors of Peripheral Arterial Disease Patients' Quality-of-Life Changes after Endovascular Treatment.

The association between chronic inflammation and depression, anxiety, anhedonia, and quality of life (QoL) has been recently emphasized. However, the pathophysiology of this relationship remains unsolved. This study aims to assess the dependence between vascular inflammation represented by eicosanoid concentration and quality of life in patients with peripheral arterial disease (PAD). A total of 175 patients undergoing endovascular treatment due to lower limbs ischemia were covered with eight years of observation after the endovascular procedure, including ankle-brachial index (ABI), color Doppler ultrasound examination, urinary leukotriene E4 (LTE4), thromboxane B2 (TXB2) and 5-Hydroxyeicosatetraenoic acid (5-HETE) measurement and quality-of-life assessment with VascuQol-6. The baseline concentrations of LTE4 and TXB2 reversely correlated with preoperative VascuQol-6 and were predictive of the postoperative values of VascuQol-6 at each follow-up. At every follow-up timepoint, the results of VascuQol-6 reflected the LTE4 and TXB2 concentrations. Higher concentrations of LTE4 and TXB2 were correlated with lower life quality during the next follow-up meeting. Changes in VascuQol-6 at eight years vs. preoperative values were reversely related to the preoperative concentrations of LTE4 and TXB2. This is the first study to confirm that changes in life quality in PAD patients undergoing endovascular treatment are highly dependent on eicosanoid-based vascular inflammation.

Oxylipin Profiles during the First Day of Mechanical Ventilation in an Intensive Care Unit Cohort: Research Letter.

Lipid mediators derived from arachidonic acid and other precursor polyunsaturated fatty acids, collectively known as oxylipins, are metabolized along different distinct pathways and play important roles in the modulation of inflammation.1,2 Blood oxylipin profiles have been shown to correlate with the survival and development of acute respiratory distress syndrome in patients with sepsis or septic shock.3–5 We aimed to explore serum oxylipin profiles using liquid chromatography coupled to tandem mass spectrometry quantification as previously described6 during the first day of mechanical ventilation in the intensive care unit (ICU). Previously, we have noted elevated plasma concentrations of thromboxane B2, prostaglandin E2, 15-hydroxyeicosatetraenoate, and 11-hydroxyeicosatetraenoate in response to experimental hyperinflation lung injury7 in a large animal model. Based on this, we hypothesized that these metabolites would increase in response to mechanical ventilation in patients. Decreases in a subset of oxylipins have been observed, however, in relation to critical illness.8With ethical approval (Linköping, 2010/427-31 and 2018/16-32), all consecutive adult patients (n = 589) with indwelling arterial cannulas after admission to the ICU in Östersund Hospital, Sweden, between February 1, 2012, and January 31, 2013, were screened for inclusion in the study cohort unless transferred from another ICU.9 Blood samples were collected in EDTA tubes during 2012 and 2013. Within 30 min, the samples were spun for 10 min at 2,000g. The plasma was then frozen in aliquots to –70°C, then unfrozen, and analyzed in 2021. In the cohort,9 147 cases with complete data and samples were identified. Of these, 22 men and 3 women with mixed diagnoses were intubated and included in the study with case characteristics in Supplemental Table 1 (https://links.lww.com/ALN/D48). Samples were collected at the time of intubation and on the following morning.Of 67 oxylipins in the analysis panel, 57 were detected (fig. 1). Of these, 23 were above the limit of quantification in at least 80% of the samples, which was the predetermined limit for oxylipins to be included in formal analysis. The detected metabolites included all major metabolic pathways, cyclooxygenase, lipoxygenase, and cytochrome P450. Complete oxylipin analysis results are given in Supplemental Table 1 (https://links.lww.com/ALN/D48). None of the oxylipins was assumed to be normally distributed. After log transformation, 19 oxylipins were deemed to be normally distributed and were thus evaluated with paired Student’s t test and Hedges’ g. The remaining four oxylipins were compared using the Wilcoxon signed-rank test (table 1). Correction for multiple comparisons was performed with the false discovery rate set to 10% for α = 0.05, yielding a significance level at P < 0.001.For samples after up to 1 day of mechanical ventilation (after intubation), 12-hydroxyeicosatetraenoate showed significantly lower plasma concentrations, and no oxylipin increased (table 1).The current study supports decreased concentrations of 12-hydroxyeicosatetraenoate in response to mechanical ventilation in contrast to previous reports of 12-hydroxyeicosatetraenoate being considered a proinflammatory mediator.10 Thromboxane B2 and prostaglandin E2 were not among the oxylipins with sufficient detection frequencies for formal analysis. In contrast to the main hypothesis, 15-hydroxyeicosatetraenoate and 11-hydroxyeicosatetraenoate did not increase during the first day of mechanical ventilation.In conclusion, this study demonstrates that several oxylipins may be detected in intensive care patients and that plasma concentration of 12-hydroxyeicosatetraenoate decreases during the first day of mechanical ventilation in the ICU.This work was supported by the Swedish Research Council VR (2014–6354; Stockholm, Sweden), Marie Sklodowska Curie Actions, Cofund, Project INCA 600398 (European Union), Åke Wiberg’s Foundation (M17-0219; Stockholm, Sweden), research funding from Umeå University (Umeå, Sweden), and the ALF-LUA cooperative Region Västerbotten-Umeå University (Umeå, Sweden) intramural research funding system.Dr. Larsson has received speaker fees for lecturing in clinical symposia sponsored by Dräger Medical (Götesburg, Sweden), and not related to this specific topic. We do not consider this relevant to the report. The authors declare no other conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.Supplemental Digital Content, https://links.lww.com/ALN/D48

Associations Of Fatty Acid Composition In Leukocyte Membranes With Systemic Inflammation In Chronic Obstructive Pulmonary Disease Progression

Background — The development of systemic inflammation is a key pathogenetic mechanism in progression of chronic obstructive pulmonary disease (COPD). Fatty acids (FAs) and their oxidized derivatives serve as essential regulators of inflammation. The relationship between systemic inflammation and FA metabolism in COPD is poorly understood. In our research, we focused on examining the FA composition of the leukocyte membrane in COPD and the FA metabolism in association with systemic inflammation. Objective — We examined 137 patients with mild, moderate, or severe COPD. The control group comprised 32 healthy non-smokers. Methods — Blood cytokines and immune cell subpopulations were evaluated by flow cytometry. The FA composition of the leukocyte membranes was analyzed by gas chromatography. The concentrations of eicosanoids (thromboxane B2 (TXB2), leukotriene B4 (LTB4)) in plasma were measured by ELISA. Results — Our results implied systemic inflammation in all patients with COPD. The analysis of the FA composition of leukocyte membrane demonstrated increased level of saturated FAs and n-6 polyunsaturated fatty acids (PUFAs), along with reduced levels of monounsaturated FAs and n-3 PUFAs, in patients with COPD. The TXB2 and LTB4 content was increasing in COPD patients. We established a significant correlation with n-6 PUFAs, immune cells, and cytokines, which was indicative of an important role of FAs in the progress of systemic inflammation in COPD. Conclusion — Thus, FA modification of immune cells in patients with chronic pathologies of the bronchopulmonary system leads not only to disruption of the cell membrane structure, but also to the pathology of immune response regulation, and contributes to the development of the inflammatory process. The latter is a decisive factor in the pathogenesis of COPD.

Augmentation by resveratrol of the inhibitory effect of ethanol on platelet aggregation

Ethanol and resveratrol have been shown to inhibit platelet aggregation. The aim of this study was to determine whether resveratrol has an additional effect on ethanol-induced inhibition of platelet aggregation. Ca2+ entry and subsequent aggregation of human platelets were measured by the fluorescence method and light transmittance method, respectively. Thromboxane B2 concentrations in media containing platelets were measured by using the enzyme-linked immunosorbent assay. Platelet aggregation induced by thrombin (0.025 U/ml) was significantly inhibited by preincubation of platelets with ethanol (0.5%). Preincubation with resveratrol (3.125 µM), which did not affect thrombin-induced platelet aggregation, significantly augmented the inhibitory effect of ethanol on platelet aggregation. Similar synergic effects of ethanol and resveratrol were found on aggregatory responses to collagen (2 µg/ml) and arachidonic acid (0.25 mM). On the other hand, the thrombin-induced increase in intracellular Ca2+ concentration ([Ca2+]i) was not affected by ethanol alone, resveratrol alone or both ethanol and resveratrol together. In nominally Ca2+-free medium, arachidonic acid (0.75 mM) caused a potent platelet aggregation, which was not affected by the presence of ethanol alone, resveratrol alone, or both of them together. Thromboxane B2 formation induced by thrombin was significantly inhibited by ethanol (0.5%) alone and resveratrol (3.125 µM) alone, and these inhibitory effects were significantly augmented in the presence of both ethanol and resveratrol together. Resveratrol shows an additive effect on ethanol-induced inhibition of platelet aggregation. This effect by resveratrol is partly explained by its inhibitory action on thromboxane A2 production in platelets. In addition, both ethanol and resveratrol attenuate platelet aggregation through acting on the Ca2+-dependent intra-platelet pathway after an increase in [Ca2+]i induced by thrombin.

Examination of the pharmacokinetics and differential inhibition of cyclooxygenase isoenzymes in New Zealand white rabbits (Oryctolagus cuniculus) by the Non-Steroidal anti-inflammatory Robenacoxib.

Effective rabbit analgesia is challenging, and there are few studies available on the newer COX-2 selective NSAIDs, such as robenacoxib. This study aimed to establish the pharmacokinetics of oral and subcutaneous robenacoxib, describe its inhibitory actions on COX enzymes, and develop dosing, using six healthy New Zealand white rabbits. Pharmacokinetics were determined from plasma concentrations after oral administration of robenacoxib (0.83-0.96 mg/kg) and also after subcutaneous administration (2mg/kg). The inhibitory actions of robenacoxib were evaluated by measuring plasma concentrations of thromboxane B2 (TBX2 ) and prostaglandin E2 (PGE2 ) as surrogate markers of cyclooxygenase enzyme isoform inhibition. The mean maximum concentration for oral and subcutaneous administration was 0.23 μg/ml and 5.82 μg/ml, respectively. Oral robenacoxib administration did not demonstrate a significant difference between any time point for PGE2 or TBX2 , though subcutaneous administration did for both. There was no significant difference in PGE2 or TBX2 concentrations at any time point when comparing subcutaneous versus oral routes. Although the results support that plasma robenacoxib exceeds the therapeutic levels compared to dogs and cats, there was little significance in the difference in the changes associated with COX-1 and COX-2 inhibition. Further studies are warranted to determine appropriate dosing, safety, and efficacy in rabbits.

Pro-thrombotic changes associated with exposure to ambient ultrafine particles in patients with chronic obstructive pulmonary disease: roles of lipid peroxidation and systemic inflammation

BackgroundExposure to particulate matter air pollution is associated with an increased risk of cardiovascular mortality in patients with chronic obstructive pulmonary disease (COPD), but the underlying mechanisms are not yet understood. Enhanced platelet and pro-thrombotic activity in COPD patients may explain their increased cardiovascular risk. We aim to explore whether short-term exposure to ambient particulate matter is associated with pro-thrombotic changes in adults with and without COPD, and investigate the underlying biological mechanisms in a longitudinal panel study. Serum concentration of thromboxane (Tx)B2 was measured to reflect platelet and pro-thrombotic activity. Lipoxygenase-mediated lipid peroxidation products (hydroxyeicosatetraenoic acids [HETEs]) and inflammatory biomarkers (interleukins [ILs], monocyte chemoattractant protein-1 [MCP-1], tumour necrosis factor alpha [TNF-α], and macrophage inflammatory proteins [MIPs]) were measured as potential mediating determinants of particle-associated pro-thrombotic changes.Results53 COPD and 82 non-COPD individuals were followed-up on a maximum of four visits conducted from August 2016 to September 2017 in Beijing, China. Compared to non-COPD individuals, the association between exposure to ambient ultrafine particles (UFPs) during the 3–8 days preceding clinical visits and the TxB2 serum concentration was significantly stronger in COPD patients. For example, a 103/cm3 increase in the 6-day average UFP level was associated with a 25.4% increase in the TxB2 level in the COPD group but only an 11.2% increase in the non-COPD group. The association in the COPD group remained robust after adjustment for the levels of fine particulate matter and gaseous pollutants. Compared to the non-COPD group, the COPD group also showed greater increases in the serum concentrations of 12-HETE (16.6% vs. 6.5%) and 15-HETE (9.3% vs. 4.5%) per 103/cm3 increase in the 6-day UFP average. The two lipid peroxidation products mediated 35% and 33% of the UFP-associated increase in the TxB2 level of COPD patients. UFP exposure was also associated with the increased levels of IL-8, MCP-1, MIP-1α, MIP-1β, TNF-α, and IL-1β in COPD patients, but these inflammatory biomarkers did not mediate the TxB2 increase.ConclusionsShort-term exposure to ambient UFPs was associated with a greater pro-thrombotic change among patients with COPD, at least partially driven by lipoxygenase-mediated pathways following exposure.Trial registrationChiCTR1900023692. Date of registration June 7, 2019, i.e. retrospectively registered.

Pharmacokinetic and pharmacodynamic profiles of a novel phospholipid-aspirin complex liquid formulation and low dose enteric-coated aspirin: results from a prospective, randomized, crossover study

Low dose enteric-coated aspirin (EC-ASA) is routinely used for secondary cardiovascular event prevention. However, absorption of EC tablets is poor, which can result in subtherapeutic antiplatelet effects. Phospholipid-aspirin liquid filled capsules (PL-ASA) are a novel FDA-approved immediate-release formulation designed to reduce gastrointestinal (GI) injury by limiting direct contact with the stomach lining. We compared the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of PL-ASA versus EC-ASA at a low dose. This randomized, open-label, crossover study assessed PK and PD following a single 81-mg dose of PL-ASA versus EC-ASA under fasting conditions in 36 volunteers without cardiovascular disease between 18 and 75 years of age. Volunteers were randomly assigned 1:1 to either PL-ASA then EC-ASA or vice versa with a minimum 14-day washout. Assessments included PK parameters for acetylsalicylic acid and salicylic acid, platelet aggregation in response to arachidonic acid (AA), and serum thromboxane B2 (TxB2) assessments over 24 h. PL-ASA was rapidly absorbed. PL-ASA reached Tmax 3 h earlier (1.01 vs. 4.00 h, p < 0.0001), with almost double the Cmax (720 vs. 368 ng/mL, p < 0.0001) and overall 44% higher exposure of acetylsalicylic acid (AUC0-t: 601 vs. 416 h*ng/mL, p = 0.0013) compared with EC-ASA. Within 1 h of dosing, PL-ASA achieved significantly lower residual platelet aggregation, which persisted for the full 24 h (median AA-LTA was 47% with PL-ASA vs. 80.5% with EC-ASA; p = 0.0022 at hour-24). Treatment with PL-ASA also resulted in significantly lower serum TxB2 concentrations at each time point compared with EC-ASA (all p-values < 0.05). PL-ASA resulted in faster and more complete aspirin absorption paralleled by more prompt and potent platelet inhibition compared with EC-ASA after a single 81 mg dose. PL-ASA represents an attractive novel aspirin formulation for the secondary prevention of cardiovascular events.Clinical Trial Registration ClinicalTrials.gov identifier: NCT04811625.

Quaternary amines exert anti-myocardial ischemia effects via regulation of energy metabolism and oxygen free radicals in myocardial cells in acute myocardial infarction rats

Purpose: To investigate the effect of quaternary amines on myocardial cells of a rat model of cardiac arrest, with respect to energy generation potential and oxygen free radicals.&#x0D; Methods: Forty-five Sprague-Dawley (SD) rats were assigned to sham, model and quaternary amine groups (each with 15 rats). After their corresponding treatments, lectrocardiogram (ECG) monitoring of the rats in the three groups at various time periods was carried out. Serum levels of myocardial enzymes, thromboxane B2 (TXB2), prostacyclin I2 (PGI2), serum carbon monoxide (CO), and changes in endothelial carbon monoxide synthase (eNOS) and endothelin (ET), were determined.&#x0D; Results: The levels of NO and eNOS were significantly reduced in model rats, relative to sham operation rats, while ET was significantly elevated in sham rats (p &lt; 0.05). There were higher levels of NO and eNOS in the quaternary amine group than in model rats, but ET was higher in quaternary amine group than in model rats. Thromboxane B2 (TXB2) concentration was higher in model rats than in sham rats (p &lt; 0.05). While PGI2 was markedly lower in quaternary group than in sham operation rats. TXB2 was lower in the quaternary amine group than in model rats, while PGI2 was significantly higher in quaternary amine group, relative to model rats (p &lt; 0.05).&#x0D; Conclusion: Quaternary amines exert anti-myocardial effects by regulating energy metabolism and oxygen free radicals in myocardial cells of congestive heart failure rats, and thus are potentially useful for the management of acute myocardial infarction.&#x0D; Keywords: Quaternary amine; Acute myocardial infarction; Electrocardiogram; Serum myocardial enzymes; Myocardial cells

Effect of indobufen vs. aspirin on platelet accumulation in patients with stable coronary heart disease after percutaneous coronary intervention: An open-label crossover study.

Purpose: This study compared the effect of indobufen with that of aspirin on platelet function in patients with stable coronary heart disease after percutaneous coronary intervention (PCI). Methods: Patients with stable coronary heart disease who had undergone PCI and received dual antiplatelet therapy (aspirin 100 mg + clopidogrel 75 mg once daily) for at least 12 months were allocated to receive indobufen 100 mg twice daily + clopidogrel 75 mg once daily, clopidogrel 75 mg once daily alone, indobufen 100 mg twice daily alone, and aspirin 100 mg once daily alone for 1 month each in an open-label crossover manner. Platelet function was assessed by using the rates of arachidonic acid (AA)-induced platelet aggregation (AA-PAR) and adenosine diphosphate (ADP)-induced platelet aggregation (ADP-PAR) measured by light transmission aggregometry, the platelet reactivity index measured by vasodilator-stimulated phosphoprotein (PRI-VASP), and the plasma and urinary thromboxane B2 (TXB2) concentrations recorded at baseline and during each treatment phase. Results: Of 56 patients enrolled, 52 completed the study. The AA-PAR was lower in the indobufen alone group than in the aspirin alone group [5.21% (3.39, 7.98) vs. 5.27% (4.06, 6.60), p = 0.038], while biologically, a difference of 0.06% may represent no significant difference; there was no significant between-group difference in the plasma [531.16 pg/ml (203.89, 1035.06) vs. 373.93 pg/ml (194.04, 681.71), p = 0.251] or urinary [3951.97 pg/ml (2006.95, 6077.01) vs. 3610.48 pg/ml (1664.60, 6247.61), p = 0.717] TXB2 concentration. When the aspirin + clopidogrel group and indobufen + clopidogrel group were compared, similar results were found for AA-PAR [3.97% (3.05, 5.12) vs. 3.83% (3.10, 5.59), p = 0.947] and both plasma [849.47 pg/ml (335.96, 1634.54) vs. 455.41 pg/ml (212.47, 1489.60), p = 0.629], and urinary [4122.97 pg/ml (2044.96, 7459.86) vs. 3812.81 pg/ml (1358.95, 6021.07), p = 0.165] TXB2 concentrations. ADP-PAR was lower in the clopidogrel alone group than in the indobufen alone group (47.04% ± 16.89 vs. 61.7% ± 10.50, p < 0.001), as was PRI-VASP (66.53% ± 18.06 vs. 77.72% ± 19.87, p = 0.002). Conclusion: These findings suggest that indobufen has antiplatelet effects similar to those of aspirin in patients with stable coronary heart disease after PCI, and may be an alternative for patients with aspirin intolerance after coronary stenting.

Evaluation of the Anti-Inflammatory and Chondroprotective Effect of Celecoxib on Cartilage Ex Vivo and in a Rat Osteoarthritis Model.

ObjectiveThe potential chondroprotective effect of celecoxib, a nonsteroidal anti-inflammatory drug and selective cyclooxygenase-2 inhibitor used to reduce pain and inflammation in knee osteoarthritis patients, is disputed. This study aimed at investigating the chondroprotective effects of celecoxib on (1) human articular cartilage explants and (2) in an in vivo osteoarthritis rat model.DesignArticular cartilage explants from 16 osteoarthritis patients were cultured for 24 hours with celecoxib or vehicle. Secreted prostaglandins (prostaglandin E2, prostaglandin F2α, prostaglandin D2) and thromboxane B2 (TXB2) concentrations were determined in medium by ELISA, and protein regulation was measured with label-free proteomics. Cartilage samples from 7 of these patients were analyzed for gene expression using real-time quantitative polymerase chain reaction. To investigate the chondroprotective effect of celecoxib in vivo, 14 rats received an intra-articular injection of celecoxib or 0.9% NaCl after osteoarthritis induction by anterior cruciate ligament transection and partial medial meniscectomy (ACLT/pMMx model). Histopathological scoring was used to evaluate osteoarthritis severity 12 weeks after injection.ResultsSecretion of prostaglandins, target of Nesh-SH3 (ABI3BP), and osteonectin proteins decreased, whereas tissue inhibitor of metalloproteinase 2 (TIMP-2) increased significantly after celecoxib treatment in the human (ex vivo) explant culture. Gene expression of a disintegrin and metalloproteinase with thrombospondin motifs 4 and 5 (ADAMTS4/5) and metalloproteinase 13 (MMP13) was significantly reduced after celecoxib treatment in human cartilage explants. Cartilage degeneration was reduced significantly in an in vivo osteoarthritis knee rat model.ConclusionsOur data demonstrated that celecoxib acts chondroprotective on cartilage ex vivo and a single intra-articular bolus injection has a chondroprotective effect in vivo.

High Risk of Cardiovascular Events in Patients, Biosynthesis of Aspirin-Resistant Thromboxane And The Risk Of Stroke, Myocardial Infarction Or Death

In a higher-risk group, we investigated if aspirin resistance, which is defined as inability to reduce production of thromboxane, enhanced the risk for cardiovascular disease. Methods: The Cardiac Outcome Preventive Assessment Study collected baseline urine samples from 5000 patients. A level of urinary 11-dehydro-thromboxane B2 was measured, which is a marker of within vitro cell generation of thromboxane, in 400 cured patients with aspirin having a cardiovascular death, stroke and infarction, stroke during a 5-year follow-up and in 400 age - and matching sex control subjects, which did not have an event, using a nested case-control design. Result: After accounting for baseline differences, the risks of infarction, strokes, or cardiac mortality rose with every fourth of 11-dihydro-thromboxane B2, with individuals in the top fourth section having a 1.9-fold greater threat than those from the lower portion (“OR, 1.9; 95% CI, 1.3 to 2.8; p=0.009). The upper quartile showed a 2-fold increased myocardial infarction risk ("OR, 2.1; 95% CI, 1.3 to 3.5; p=0.07) and a 3.6-fold elevated risk of cardiac death ("OR, 3.6; 95% CI, 1.78to 7.5; p=0.01) than the lower quartile. Conclusions: the 11-dehydro thromboxane B2 level in urine, better determine the risk of cardiovascular events or cardiovascular death in aspirin-treated patients. These findings also depicts that patients with elevated urine 11-dehydro thromboxane B2 concentrations are more impervious to aspirin, and could profit from greater antiplatelet medications or therapies that even more efficiently stop thromboxane generation in vivo or activities.

Concentrations of PGE2 and TXB2 in the Eyes of Mice with Disseminated Acanthamoebiasis.

Previous studies have shown that Acanthamoeba spp. may invade the eyes by migrating along the optic nerve to the eyes from the brain. This study aimed to confirm the presence of inflammation in the eyes of mice with disseminated acanthamoebiasis by examining prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) concentrations in the eyes of immunocompetent and immunocompromised mice intranasally inoculated with Acanthamoeba spp. The PGE2 concentration was statistically significantly lower in the immunocompromised amoebae-infected mice on 8 dpi compared with the noninfected group of animals, and it was higher in the eyes of immunosuppressed amoebae-infected mice on 16 dpi than in the control group of animals. There was a statistically significant lower TXB2 concentration in the eyes of immunocompetent infected mice compared with the noninfected group on 8 dpi. However, on 24 dpi, we noted statistically significant higher TXB2 levels in the immunocompetent infected mice than in the control group. In immunocompromised mice, there was a lower TXB2 level on 8 dpi than in control mice. This study confirmed the existence of an inflammatory process in the eyes of immunocompetent and immunocompromised mice infected with Acanthamoeba spp. without damaged corneas.

Arterial thromboxane A2-induced transient contraction after IL-1β exposure

The involvement of thromboxane A2 (TXA2) in systemic inflammation and infection is well recognized. However, there are few reports on the involvement of prostanoids in warm shock (the initial pathology of sepsis). Previous studies showed that interleukin (IL)-1β causes a rapid inducible nitric oxide synthase/nitric oxide (iNOS/NO)-mediated relaxation in peripheral blood vessels during warm shock. Furthermore, a transient contraction was seen before this relaxation occurred. The present study aimed to elucidate the mechanism of this transient contraction. We measured isometric tension changes in the superior mesenteric arteries from normal male Wistar rats by adding IL-1β at the point of maximum contraction by phenylephrine (Ph). The same study was performed for each vessel pretreated with various inhibitors, including SQ29548, a TXA2 receptor antagonist, 30 min before Ph contraction. In addition, the concentration of thromboxane B2 (TXB2) in SMA was measured by probe electrospray ionization. Treatment of endothelial vessels with cyclooxygenase 1 (COX1)/2 inhibitors SC560/NS398 and TXA2 receptor antagonist SQ29548 suppressed IL-1β–induced transient contractions. This transient contraction reaction was derived from TXA2. Additionally, gene expression of COX2/TXA2 synthetase and the concentration of TXB2 were significantly increased in IL-1β-exposed vessels. It was demonstrated for the first time in inflamed blood vessels that endothelial cell-derived COX2/TXA2 is induced before iNOS and causes transient contractions. TXA2 may be considered an early sign of warm shock or as a biological defense mechanism in the early stages of septic shock.

The midterm differential effects of heat-not-burn and conventional cigarettes on coronary flow, vascular function and oxidative stress are independent of nicotine levels

Abstract Introduction Heat-not-burn cigarette (HNBC) constitutes a non-combustible smoke product linked to reduced exposure to carbon monoxide (CO). Methods We compared the effects of HNBC to those of tobacco cigarette (TCig) on endothelial and coronary function as well as on nicotine levels, oxidative stress and platelet activation after 1 month of switching to HNBC. We examined 75 smokers. Of those, 50 were switched to HNBC and 25 continued Tcig for 1 month. At baseline and at 1 month, we assessed a) coronary flow reserve (CFR) by echocardiography b) flow-mediated dilation (FMD) c) Cotinine blood levels, a stable metabolite of nicotine d) malondialdehyde (MDA), a marker of oxidative stress and thromboxane B2 (TXB2), a marker of platelet activation e) the exhaled CO and the number of cigarettes and/or heat stick of HNBC used. Fagerstrom score, a marker of dependence from smoking habit was also calculated. Results Compared to Tcig smoking, switching to HNBC for 1-month improved CO (difference in CO between groups: 10.42 ppm; 95% CI 3.07 to 17.76, p=0.007), FMD (difference in FMD=4.3%; 95% CI: 1.23 to 7.51, p=0.009; and CFR (difference in CFR =0.98; 95% CI: 0.23 to 1.80, p=0.02). MDA and TXB2 concentration significantly decreased in subjects switching to HNBC compared to tobacco smokers (difference MDA=0.38 nmol/L; 95% CI 0.10 to 0.66, p=0.009, 45pg/mL; 95% CI 5.28 to 86.31, p=0.03). None of the aforementioned parameters changed in the control group at 1 month compared to baseline (p&amp;gt;0.05). Cotinine blood levels were similar between the TC cig and HNBC group both at baseline and after one month of use (p&amp;gt;0.05). However, cotinine blood levels at baseline and 1 month correlated with the number cigarettes used at baseline (r=0.45 p=0.04) or the number of heat sticks used at one month (r=0.50, p=0.03) respectively, Baseline Fagerstrom score was also associated with number of heat sticks used at 1 month (r=0.48, p=0.04) and cotinine levels at baseline and at 1 month (p=0.50, p=0.03 and r=0.57, p=0.01 respectively). Conclusions HNBCs exert a less detrimental effect on vascular function platelet activation and oxidative stress than tobacco smoking that is independent of nicotine levels and is linked with the parallel reduction the exhaled of CO. Funding Acknowledgement Type of funding sources: None.

COX-2 pathway is upregulated in ultra-high risk individuals for psychosis

Background The identification of Ultra-High Risk (UHR) individuals is thought to be useful for early intervention to improve psychosis outcomes. However, transition rates vary widely, and there is an effort to make these criteria more specific and accurate. Neuroinflammation has been discussed in the pathophysiology of psychosis. The metabolism of eicosanoids is a key process in inflammatory states. Therefore, we investigated whether the study of the inflammatory COX-2 pathway through the quantification of the eicosanoid levels can be a useful approach for the characterisation of UHR individuals. Methods One hundred and twenty-two individuals were included in this study (67 UHR and 55 controls) based on performance on the Prodromal Questionnaire. UHR status was assessed by Structured Interview for Prodromal Syndromes (SIPS). We determined the levels of Prostaglandin F2α (PGF2α), Prostaglandin E2 (PGE2), and Thromboxane B2 (TxB2) in plasma using ELISA assays. Results Concentrations of PGE2 and TxB2 were increased in UHR compared to controls (p = 0.01 and p < 0.05, respectively). PGE2 and PGF2α levels were correlated to negative symptoms (p < 0.01 and p < 0.05), whereas TxB2 correlated with positive symptoms (p = 0.05) as assessed by the SIPS. Conclusions Our findings suggest that overactivation of the COX-2 pathway may be related to an increased risk for psychosis. However, our data do not allow us to draw conclusions related to the cause-effect mechanisms. Future studies should determine whether the levels of the eicosanoids have a predictive value for the transition of UHR to frank psychosis.

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.

Thromboxane Synthesis and Platelet Protein Release During Simulated Extracorporeal Circulation

Platelet secretion induced by certain soluble aggregating agents is associated with thromboxane formation. Activation of platelets by artificial surfaces may involve similar biochemical pathways. Therefore, we monitored platelet release and formation of thromboxane B2. the stable end-product of thromboxane A2, during simulated extracorporeal circulation where contact between blood and synthetic surfaces is extensive. Fresh heparinized human blood was recirculated for 2 hr at 37°C at 1 liter/min in circuits (0.95 sqm) constructed of standard silicone rubber components (0.1 sqm) and a spiral coil membrane oxygenator (0.85 sqm). Within 2 min of recirculation, plasma levels of the platelet-specific protein, low-affinity platelet factor 4 (LA-PF4) rose from <1.5% to 11 % ±3% SEM of that which was released by triton X-100, indicating significant release of platelet α-granule contents. This occurred despite the absence of detectable thromboxane B2 in plasma (<0.5 pmole/ml). Between 2 and 15 min, plasma levels of LA-PF4 increased from 11% to 42% ± 3%, and plasma thromboxane B2 concentrations rose to 3.2 pmole/ml. Subsequently, thromboxane B2 levels continued to rise to 9.8 pmole/ml by 2 hr. Thromboxane B2 was not detected in blood from donors who had ingested aspirin, and the extent of platelet secretion was reduced by about 50% (25% at 2 hr). Thus, although a component of platelet granule release during extracorporeal recirculation appears to be associated with thromboxane synthesis, considerable release of LA-PF4 may occur by thromboxanβ-indβpen-dent pathways.

Glycation and acetylation sites on fibrinogen in plasma fibrin clot of patients with type 2 diabetes: Effects of low-dose acetylsalicylic acid

Acetylsalicylic acid (ASA) and type 2 diabetes mellitus (T2DM) affect fibrin clot properties through fibrinogen acetylation or glycation. We aimed to identify glycation and acetylation sites on fibrinogen in plasma fibrin clot of T2DM patients with respect to effects of ASA and fibrin clot properties. In fibrin clots generated from plasma of 9 T2DM patients, we performed mass-spectrometric analysis of Nε-fructosyl-(FL), Nε-carboxyethyl-(CEL) and Nε-carboxymethyl-lysine (CML), and acetylation sites, before and after one-month administration of 75 mg/d ASA confirmed with determination of thromboxane B2 concentration (TXB2), along with clot permeability and lysis time, and thrombin generation.In the proteomic analysis, 216 proteins were identified. Among 10 glycation sites identified in α, 10 in β and 6 in γ fibrinogen chain, there were 17 FL, 5 CEL and 4 CML sites. Some of glycation sites in fibrinogen were previously reported to be involved in cross-linking by factor XIII (αK-208, αK-448 and αK-539) and plasmin cleavage (αK-81). There were 7 acetylation sites in α and β chains, and none in fibrinogen γ chain. Two acetylation sites were identical with FL sites (αK-195 and β-247), while one with CML site (βK-353). In 7 patients with low post-ASA TXB2, intensity of acetylation, as well as clot properties were unaffected by ASA. This study identifies glycation and acetylation sites on fibrinogen in plasma fibrin clot of T2DM and supports the view that low-dose ASA does not increase fibrinogen acetylation in T2DM. Our findings suggest that glycation may block sites previously identified to be acetylated in vitro.

Cyclooxygenases 1 and 2 inhibition and analgesic efficacy of dipyrone at different doses or meloxicam in cats after ovariohysterectomy

ObjectiveTo evaluate the cyclooxygenases (COX) inhibition, adverse effects and analgesic efficacy of dipyrone or meloxicam in cats undergoing elective ovariohysterectomy. Study designProspective, blinded, randomized, clinical study. AnimalsA total of 30 healthy young cats. MethodsThe cats were randomly assigned to three postoperative groups: D25 (dipyrone 25 mg kg−1 every 24 hours), D12.5 (dipyrone 12.5 mg kg−1 every 12 hours) and M (meloxicam 0.1 mg kg−1 every 24 hours). In the first 24 hours, the drugs were administered intravenously (IV), and then orally for 6 (dipyrone) or 3 days (meloxicam). Prostanoids thromboxane B2 and prostaglandin E2 concentrations served as indicators of COX activity and, with physiological variables and pain and sedation scores, were measured for 24 hours after first analgesic administration. Rescue analgesia (tramadol, 2 mg kg−1 IV) was provided if Glasgow feline composite measure pain scale (CMPS-Feline) ≥5. Laboratory tests included symmetric dimethylarginine and adverse effects were evaluated regularly up to 7 and 10 days after surgery, respectively. Parametric and nonparametric data were analyzed with two-way anova and Kruskal-Wallis tests, respectively (p < 0.05). ResultsIn the first half hour after analgesic administration, COX-1 activity was close to zero and remained significantly lower than before drug administration for 24 hours in all groups. The inhibition of COX-2 activity was significant for 30 minutes in all groups and up to 4 hours in group M. No alterations in laboratory tests or significant adverse effects were observed. Pain scores and need for rescue analgesia did not differ statistically among groups. ConclusionsDipyrone at both doses and meloxicam provided a nonselective inhibition of COX-1 and -2 activities and effective analgesia without causing significant adverse effects or laboratory tests alterations. Clinical relevanceDipyrone at both doses provides equally effective analgesia without causing adverse effects in cats undergoing ovariohysterectomy.