Reference interval establishment and correlation research of urine thromboxane metabolites: Unveiling new possibilities in platelet activation.

BACKGROUND: Thromboxane metabolites could indirectly reflect platelet activation, among which 11-dehydro-thromboxane B2 (11dhTxB2) and 11-dehydro-2, 3-dinor thromboxane B2 (11dh23dinorTxB2) are two stable metabolites that are abundant in urine, and both are closely related to disease progression and drug use. However, most clinical application studies have focused on the single indicator of 11dhTxB2. We propose an LC-MS/MS method suitable for routine clinical screening with simultaneous determination of both metabolites and conduct preliminary studies in different populations. METHODS AND RESULTS: The thromboxane metabolites were extracted by liquid-liquid extraction and determined by LC-MS/MS. Reference intervals (RI) were established in 333 healthy adults and validated in 25 patients with coronary atherosclerosis (CA). This LC-MS/MS method was over a wide quantitative range (0.1-10 µmol/L), the imprecision and accuracy were 5.2 %-11 % and 89.3 %-106.5 %, and was suitable for clinical routine quantitative screening. The 95th percentile RI of unire 11dhTxB2 was 1220 (95 % CI: 1048, 1376) pg mg Cr -1, for 11dh23dinorTxB2, RI was 908 (95 % CI: 821, 1102) pg mg Cr -1. For the first time, we found a significant correlation between 11dhTxB2 and 11dh23dinorTxB2 in both healthy adults (r = 0.67, P < 0.001) and CA patients (r = 0.77, P < 0.001). CONCLUSION: The establishment of RI provides a reference for diseases related to platelet activation and the use of drugs, and the first discovery of the correlation between 11dhTxB2 and 11dh23dinorTxB2 in urine provides a new possibilitie for the diagnostic and prognostic of cardiovascular diseases.

Chronic edible dosing of Δ9-tetrahydrocannabinol (THC) in nonhuman primates reduces systemic platelet activity and function.

Cannabis usage has steadily increased as acceptance is growing for both medical and recreational reasons. Medical cannabis is administered for treatment of chronic pain based on the premise that the endocannabinoid system signals desensitize pain sensor neurons and produce anti-inflammatory effects. The major psychoactive ingredient of cannabis is Δ9-tetrahydrocannabinol (THC) that signals mainly through cannabinoid receptor-1 (CBr), which is also present on nonneuron cells including blood platelets of the circulatory system. In vitro, CBr-mediated signaling has been shown to acutely inhibit platelet activation downstream of the platelet collagen receptor glycoprotein (GP)VI. The systemic effects of chronic THC administration on platelet activity and function remain unclear. This study investigates the effects of chronic THC administration on platelet function using a nonhuman primate (NHP) model. Our results show that female and male NHPs consuming a daily THC edible had reduced platelet adhesion, aggregation, and granule secretion in response to select platelet agonists. Furthermore, a change in bioactive lipids (oxylipins) was observed in the female cohort after THC administration. These results indicate that chronic THC edible administration desensitized platelet activity and function in response to GPVI- and G-protein coupled receptor-based activation by interfering with primary and secondary feedback signaling pathways. These observations may have important clinical implications for patients who use medical marijuana and for providers caring for these patients.

Different forms of vitamin E and metabolite 13'-carboxychromanols inhibit cyclooxygenase-1 and its catalyzed thromboxane in platelets, and tocotrienols and 13'-carboxychromanols are competitive inhibitors of 5-lipoxygenase.

Cyclooxygenase (COX-1 and COX-2)- and 5-lipoxygenase (5-LOX)-catalyzed biosynthesis of eicosanoids play important roles in inflammation and chronic diseases. The vitamin E family has four tocopherols and tocotrienols. We have shown that the metabolites of δ-tocopherol (δT) and δ-tocotrienol (δTE), i.e., δT-13'-carboxychromanol (COOH) and δTE-13'-COOH, respectively, inhibit COX-1/-2 and 5-LOX activity, but the nature of how they inhibit 5-LOX is not clear. Further, the impact of tocopherols and tocotrienols on COX-1/-2 or 5-LOX activity has not been fully delineated. In this study, we found that tocopherols and tocotrienols inhibited human recombinant COX-1 with IC50s of 1-12 µM, and suppressed COX-1-mediated formation of thromboxane in collagen-stimulated rat's platelets with IC50s of 8-50 µM. None of the vitamin E forms directly inhibited COX-2 activity. 13'-COOHs inhibited COX-1 and COX-2 enzyme activity with IC50s of 3-4 and 4-10 µM, respectively, blocked thromboxane formation in collagen- and ionophore-stimulated rats' platelets with IC50s of 1.5-2.5 µM, and also inhibited COX-2-mediated prostaglandins in stimulated cells. Using enzyme kinetics, we observed that δT-13'-COOH, δTE-13'-COOH and δTE competitively inhibited 5-LOX activity with Ki of 1.6, 0.8 and 2.2 µM, respectively. These compounds decreased leukotriene B4 from stimulated neutrophil-like cells without affecting translocation of 5-LOX from cytosol to the nucleus. Our study reveals inhibitory effects of vitamin E forms and 13'-COOHs on COX-1 activity and thromboxane formation in platelets, and elucidates mechanisms underlying their inhibition of 5-LOX. These observations are useful for understanding the role of these compounds in disease prevention and therapy.

Acute severe SARS COVID-19 patients produce pro-resolving lipids mediators and eicosanoids.

OBJECTIVE: This study aimed to evaluate the eicosanoid and pro resolutive parameters in SARS COVID-19 patients with the severe acute respiratory syndrome. PATIENTS AND METHODS: Fourteen male patients with an acute respiratory syndrome caused by SARS COVID-19 and four healthy controls were evaluated by measuring the following parameters in plasma: Polyunsaturated fatty acids: EPA, DHA, ARA, and DPA. Specialized Pro-resolving mediators (SPMs) (including monohydroxy-containing precursors 17-HDHA, 18-HEPE, 14-HDHA) resolvins, maresins, protectins, and lipoxins. The eicosanoids group included prostaglandins, thromboxanes, and leukotrienes. RESULTS: Plasma from COVID-19 patients presented higher amounts of pro-inflammatory and pro-thrombotic lipid mediators as compared to healthy subjects (65.7 pg/ml vs. 10.2 pg/ml), including thromboxane (2142.6 pg/ml vs. 10.4 pg/ml), and the ratio between total plasma pro-inflammatory mediators versus total SPM's was 13.2 to 0,4, respectively. CONCLUSIONS: A clear disbalance favoring the pro-inflammatory axis is described, showing the need to perform future clinical interventions in these patients using SPM's or monohydroxylated lipid mediators derivates from fatty acids.

Relationship between the n-3 index, serum metabolites and breast cancer risk.

The present study aimed to investigate the relationship between the n-3 index, serum metabolites and breast cancer risk. A total of 104 newly diagnosed breast cancer patients and 70 healthy controls were recruited. The erythrocyte phospholipid fatty acid composition was determined by gas-liquid chromatography, and the n-3 index was calculated with the percentage of eicosapentaenoic acid plus docosahexaenoic acid in total fatty acids. Serum metabolomic profiles were analyzed by UHPLC-Q-Exactive Orbitrap/MS. The results showed that the erythrocyte phospholipid n-3 index was significantly lower in breast cancer patients than in healthy controls, and it was inversely associated with breast cancer risk (OR = 0.60; 95% CI: 0.36-0.84). Metabolomics analyses showed that serum 16α-hydroxy dehydroepiandrosterone (DHEA) 3-sulfate, lysophatidylethanolamines (LPE) 22:0/0:0 and hexanoylcarnitine were significantly higher, while thromboxane B3, prostaglandin E3 (PGE3) and 18ß-glycyrrhetinic acid were significantly lower in breast cancer patients than those in healthy controls. In addition, serum 16α-hydroxy DHEA 3-sulfate was inversely correlated with the n-3 index (r = -0.412, p = 0.036). In conclusion, our findings suggest that the lack of n-3 PUFAs might be a potential risk factor for breast cancer, and the serum metabolite 16α-hydroxy DHEA 3-sulfate may play an important role in linking n-3 PUFA deficiency and breast disease etiology.

The Effect of Omega-3 Fatty Acids on Thromboxane, Brain-Derived Neurotrophic Factor, Homocysteine, and Vitamin D in Depressive Children and Adolescents: Randomized Controlled Trial.

In the DEPOXIN project, we have found that a high ratio of omega-6/omega-3 fatty acids (FA) is associated with worsening of depressive symptoms in children and adolescents with depressive disorder (DD) and that the 12-week omega-3 FA supplementation modulates DD symptoms. Here we present our results of the secondary outcomes: the levels of thromboxane (TXB), brain-derived neurotrophic factor (BDNF), homocysteine (HCy) and vitamin D. Fifty-eight patients were randomized into two arms. One group received a fish oil emulsion enriched with omega-3 FA, and the other received a sunflower oil emulsion containing omega-6 FA, for 12 weeks. Depressive symptoms were evaluated, using the Child's Depressive Inventory (CDI). The patients with DD had elevated TXB levels and decreased vitamin D levels, as compared to healthy controls. Both CDI and omega-6/omega-3 ratio correlated positively with TXB and negatively with BDNF at baseline. Compared to the omega-6 FA group, the supplementation with omega-3 FA for 12 weeks significantly reduced plasma TXB (p = 0.024) and increased BDNF (p = 0.011) levels. No changes in HCy and vitamin D were observed. Our results demonstrate the possible role of TXB and BDNF in the pathophysiology of DD and the benefits of omega-3 FA supplementation. The study was registered with the ISRCTN registry (ISRCTN81655012).

Exercise-Induced Changes in Bioactive Lipids Might Serve as Potential Predictors of Post-Exercise Hypotension. A Pilot Study in Healthy Volunteers.

Post-exercise hypotension (PEH) is the phenomenon of lowered blood pressure after a single bout of exercise. Only a fraction of people develops PEH but its occurrence correlates well with long-term effects of sports on blood pressure. Therefore, PEH has been suggested as a suitable predictor for the effectivity of exercise as therapy in hypertension. Local vascular bioactive lipids might play a potential role in this context. We performed a cross-over clinical pilot study with 18 healthy volunteers to investigate the occurrence of PEH after a single short-term endurance exercise. Furthermore, we investigated the plasma lipid profile with focus on arachidonic acid (AA)-derived metabolites as potential biomarkers of PEH. A single bout of ergometer cycling induced a significant PEH in healthy volunteers with the expected high inter-individual variability. Targeted lipid spectrum analysis revealed significant upregulation of several lipids in the direct post-exercise phase. Among these changes, only 15- hydroxyeicosatetranoic acid (HETE) correlated significantly with the extent of PEH but in an AA-independent manner, suggesting that 15-HETE might act as specific PEH-marker. Our data indicate that specific lipid modulation might facilitate the identification of patients who will benefit from exercise activity in hypertension therapy. However, larger trials including hypertonic patients are necessary to verify the clinical value of this hypothesis.

Effect of natural polyphenols on thromboxane levels in children with Crohn's disease.

OBJECTIVES: The aim of this study was to investigate the relationship between thromboxane levels and oxidative stress in children with Crohn´s disease (CD), and examine the effect of natural polyphenolic compounds on thromboxane levels. METHODS: This study involved 14 children suffering from CD and 15 healthy controls. Patients were receiving the polyphenolic extract Pycnogenol for 10 weeks. Plasma levels of the static and dynamic forms of thromboxane B2 as well as their metabolite 11-dehydro thromboxane B2 in urine were determined. RESULTS: In comparison to controls, CD patients had significantly higher levels of the static and dynamic forms of thromboxane B2. Pycnogenol decreased the level of the dynamic form of thromboxane B2 after 10 weeks of administration. CONCLUSIONS: Paediatric Crohn's disease is associated with higher thromboxane levels. Our results indicate that Pycnogenol administration reduces thromboxane levels, which may positively influence some clinical symptoms of CD such as thromboembolic episodes (Tab. 3, Ref. 49).

Effects of high- and low-dose aspirin on adaptive immunity and hypertension in the stroke-prone spontaneously hypertensive rat.

Despite its well-known antithrombotic properties, the effect of aspirin on blood pressure (BP) and hypertension pathology is unclear. The hugely varying doses used clinically have contributed to this confusion, with high-dose aspirin still commonly used due to concerns about the efficacy of low-dose aspirin. Because prostaglandins have been shown to both promote and inhibit T-cell activation, we also explored the immunomodulatory properties of aspirin in hypertension. Although the common preclinical high dose of 100 mg/kg/d improved vascular dysfunction and cardiac hypertrophy, this effect was accompanied by indices of elevated adaptive immunity, renal T-cell infiltration, renal fibrosis, and BP elevation in stroke-prone spontaneously hypertensive rats and in angiotensin II-induced hypertensive mice. The cardioprotective effects of aspirin were conserved with a lower dose (10 mg/kg/d) while circumventing heightened adaptive immunity and elevated BP. We also show that low-dose aspirin improves renal fibrosis. Differential inhibition of the COX-2 isoform may underlie the disparate effects of the 2 doses. Our results demonstrate the efficacy of low-dose aspirin in treating a vast array of cardiovascular parameters and suggest modulation of adaptive immunity as a novel mechanism underlying adverse cardiovascular profiles associated with COX-2 inhibitors. Clinical studies should identify the dose of aspirin that achieves maximal cardioprotection with a new awareness that higher doses of aspirin could trigger undesired autoimmunity in hypertensive individuals. This work also warrants an evaluation of high-dose aspirin and COX-2 inhibitor therapy in sufferers of inflammatory conditions who are already at increased risk for cardiovascular disease.-Khan, S. I., Shihata, W. A., Andrews, K. L., Lee, M. K. S., Moore, X.-L., Jefferis, A.-M., Vinh, A., Gaspari, T., Dragoljevic, D., Jennings, G. L., Murphy, A. J., Chin-Dusting, J. P. F. Effects of high- and low-dose aspirin on adaptive immunity and hypertension in the stroke-prone spontaneously hypertensive rat.

PDK1 governs thromboxane generation and thrombosis in platelets by regulating activation of Raf1 in the MAPK pathway.

Essentials Phosphoinositide 3-kinase and MAPK pathways crosstalk via PDK1. PDK1 is required for adenosine diphosphate-induced platelet activation and thromboxane generation. PDK1 regulates RAF proto-oncogene Ser/Thr kinase (Raf1) activation in the MAPK pathway. Genetic ablation of PDK1 protects against platelet-dependent thrombosis in vivo. SUMMARY: Background Platelets are dynamic effector cells with functions that span hemostatic, thrombotic and inflammatory continua. Phosphoinositide-dependent protein kinase 1 (PDK1) regulates protease-activated receptor 4-induced platelet activation and thrombus formation through glycogen synthase kinase3ß. However, whether PDK1 also signals through the ADP receptor and its functional importance in vivo remain unknown. Objective To establish the mechanism of PDK1 in ADP-induced platelet activation and thrombosis. Methods We assessed the role of PDK1 on 2MeSADP-induced platelet activation by measuring aggregation, thromboxane generation and phosphorylation events in the presence of BX-795, which inhibits PDK1, or by using platelet-specific PDK1 knockout mice and performing western blot analysis. PDK1 function in thrombus formation was assessed with an in vivo pulmonary embolism model. Results PDK1 inhibition with BX-795 reduced 2-methylthio-ADP (2MeSADP)-induced aggregation of human and murine platelets by abolishing thromboxane generation. Similar results were observed in pdk1-/- mice. PDK1 was also necessary for the phosphorylation of mitogen-activated protein kinase kinase 1/2 (MEK1/2), extracellular signal-regulated kinase 1/2, and cytosolic phospholipase A2, indicating that PDK1 regulates an upstream kinase in the mitogen-activated protein kinase (MAPK) pathway. We next determined that this upstream kinase is Raf-1, a serine/threonine kinase that is necessary for the phosphorylation of MEK1/2, as pharmacological inhibition and genetic ablation of PDK1 were sufficient to prevent Raf1 phosphorylation. Furthermore, in vivo inhibition or genetic ablation of PDK1 protected mice from collagen/epinephrine-induced pulmonary embolism. Conclusion PDK1 governs thromboxane generation and thrombosis in platelets that are stimulated with 2MeSADP by regulating activation of the MAPK pathway.

Prostacyclin, thromboxane and glomerular filtration rate are abnormal in sickle cell pregnancy.

BACKGROUND: Pregnancy increases the risk of morbidity and mortality in sickle cell disease. We previously showed pregnant women with sickle cell disease to have a relatively low plasma renin concentration in late pregnancy, associated with a lack of the expected plasma volume expansion. We hypothesized this to be due to increased systemic vascular resistance through an imbalance between the vasodilator prostacyclin and vasoconstrictor thromboxane, associated with decreased glomerular filtration rate (GFR). OBJECTIVE: To compare estimated prostacyclin, thromboxane and GFR in non-pregnant and pregnant women with hemoglobin SS (HbSS) and AA (HbAA). STUDY DESIGN: Four groups of 20 normotensive, nulliparous women were studied in Lagos, Nigeria: pregnant HbSS or HbAA women at 36-40 weeks gestation; non-pregnant HbSS and HbAA controls. We measured stable metabolites of prostacyclin and thromboxane A2 by enzyme-linked immunosorbent assay; GFR using the Cockcroft-Gault equation. Data analysis was by independent (Student's) t-test or Mann-Whitney U test for comparisons between any two groups of continuous variables, univariate ANOVA for multiple groups and Pearson's correlation coefficient for degree of association between variables. RESULTS: HbSS women had lower serum 6-keto-PGF1α concentrations than HbAA, whether pregnant or non-pregnant (P<0.001; P<0.004 respectively). Conversely, pregnant HbSS women had higher serum TxB2 (P<0.001); non-pregnant HbSS women had non-significantly higher TxB2 concentrations. The 6-keto-PGF1α:TxB2 ratio was markedly increased (pro-vasodilatory) in HbAA pregnancy (P<0.001) but reduced in HbSS pregnancy (P = 0.037). GFRs (mL/min) were higher in non-pregnant HbSS than HbAA (P<0.008) but only marginally raised in HbSS women in late pregnancy (P = 0.019) while markedly raised in HbAA pregnancy (P<0.001). CONCLUSION: The lower ratio of prostacyclin-thromboxane metabolites in HbSS pregnancy may indicate endothelial damage and an increased tendency to vasoconstriction and clotting. If confirmed by subsequent longitudinal studies, interventions to increase prostacyclin and reduce thromboxane, such as low dose aspirin, may be potentially useful in their management.

The improvement of walking abilities and endothelial function after the supervised training treadmill program (STTP) in patients with peripheral artery disease (PAD) is not related to prostacyclin and thromboxane release.

BACKGROUND: In this prospective study we evaluated the relationship between thromboxane B2 (TXB2), prostacyclin (PGI2) and lactate concentrations, and the improvement of walking abilities and endothelial function in patients with peripheral artery disease (PAD) undergoing a supervised treadmill training program (STTP). METHODS: A total of fifty-nine patients with stable intermittent claudication were included into a 12-week long STTP. Changes in blood pressure, biochemical parameters, ankle/brachial index (ABI), flow-mediated dilatation (FMD), maximal walking time (MWT) and pain-free walking time (PFWT) were assessed before and after STTP. Additional baseline and post-STTP measurements were taken for blood lactate, and TXB2 and PGI2 urinary derivatives before and after maximal exercise (ME). RESULTS: The MWT improved significantly after STTP by 91% (p<0.0001) and PFWT by 97% (p<0.0001). Also, ABI values improved significantly after STTP in all patient groups and was more pronounced in those with longer MWT at baseline. FMD values increased by 45% (p<0.0001) after STTP. Urinary 11-dehydro-thromboxane B2 and 2,3-dinor-6-keto-PGF1α concentration tend to decrease after STTP and their ratio remained unchanged. Lactate levels did not change after the treadmill training program. Hs-CRP and fibrinogen concentration decreased significantly after STTP only in patients with longer MWT at baseline-fourth quartile. CONCLUSIONS: STTP in patients with PAD showed significantly improved walking abilities and endothelial function. Lactate production, TXB2 release, and PGI2 release are not directly correlated with improvement of endothelial function and walking abilities. Patients with better-walking abilities at baseline derive greater clinical and metabolic benefits from STTP.

Leukaemia-associated Rho guanine nucleotide exchange factor (LARG) plays an agonist specific role in platelet function through RhoA activation.

Leukemia-Associated RhoGEF (LARG) is highly expressed in platelets, which are essential for maintaining normal haemostasis. We studied the function of LARG in murine and human megakaryocytes and platelets with Larg knockout (KO), shRNA-mediated knockdown and small molecule-mediated inhibition. We found that LARG is important for human, but not murine, megakaryocyte maturation. Larg KO mice exhibit macrothrombocytopenia, internal bleeding in the ovaries and prolonged bleeding times. KO platelets have impaired aggregation, α-granule release and integrin α2bß3 activation in response to thrombin and thromboxane, but not to ADP. The same agonist-specific reductions in platelet aggregation occur in human platelets treated with a LARG inhibitor. Larg KO platelets have reduced RhoA activation and myosin light chain phosphorylation, suggesting that Larg plays an agonist-specific role in platelet signal transduction. Using two different in vivo assays, Larg KO mice are protected from in vivo thrombus formation. Together, these results establish that LARG regulates human megakaryocyte maturation, and is critical for platelet function in both humans and mice.

Enhanced performance for the analysis of prostaglandins and thromboxanes by liquid chromatography-tandem mass spectrometry using a new atmospheric pressure ionization source.

Eicosanoids, including prostaglandins and thromboxanes are lipid mediators synthetized from polyunsaturated fatty acids. They play an important role in cell signaling and are often reported as inflammatory markers. LC-MS/MS is the technique of choice for the analysis of these compounds, often in combination with advanced sample preparation techniques. Here we report a head to head comparison between an electrospray ionization source (ESI) and a new atmospheric pressure ionization source (UniSpray). The performance of both interfaces was evaluated in various matrices such as human plasma, pig colon and mouse colon. The UniSpray source shows an increase in method sensitivity up to a factor 5. Equivalent to better linearity and repeatability on various matrices as well as an increase in signal intensity were observed in comparison to ESI.

A mathematical model of the metabolic process of atherosclerosis.

A mathematical model of the metabolic process of atherosclerosis is constructed. The functioning of the polyenzymatic prostacyclin-thromboxane system of blood and the influence of a level of "bad cholesterol", namely low density lipoproteins (LDL), on it are studied. With the help of the numerical experiment, we analyze the influence of the concentration of molecules of fat on hemostasis of blood in blood vessels. The kinetic curves for components of the system, phase-periodic bifurcation diagrams, attractors for various modes, and Poincaré cross-section and image of a strange attractor are constructed. The complete spectra of Lyapunov's exponents, divergencies, KS-entropies, predictability horizons, and Lyapunov dimensions of the fractality of strange attractors are calculated. Conclusions about the structural-functional connections, which determine the dependence of hemostasis of a circulatory system on the level of cholesterol in blood are drawn.

Endothelial dysfunction in young healthy men is associated with aspirin resistance.

The aim of this study was to investigate the relation between endothelial dysfunction and aspirin response in a young healthy population (102 men aged 18-40). Initial concentrations of the NO pathway metabolites (ADMA, l-arginine, SDMA), cardiovascular risk markers, oxidative stress markers (MDA, thiol index), sICAM1, sVCAM1, PAI-1, sE-selectin, sP-selectin, VEGF, thromboxane B2, 6-keto-PGF1α and arachidonate-induced platelet aggregation (to separate aspirin resistant from sensitive group) were measured. Flow-mediated-vasodilation (FMD) was measured before and after intravenous infusion of 16.0 g of l-arginine. Measurements were repeated following aspirin administration (75 mg/24 h) for 4 days. Both groups were homogenous regarding demographic and biochemical characteristics reflecting cardiovascular risk. Aspirin resistant subjects were characterized by lower baseline FMD and higher FMD following aspirin and l-arginine treatment, as compared to aspirin sensitive control. MDA and nitrotyrosine were greater, whereas thiol index was lower in aspirin resistant men. The sICAM1, sVCAM1, PAI-1, sE-selectin, sP-selectin and VEGF levels were similar in the analyzed groups. Thromboxane in aspirin resistant subjects was greater both at baseline and following aspirin therapy. However, a significant decrease following aspirin treatment was present in both groups. Aspirin resistance in young men is associated with endothelial dysfunction, which could be due to oxidative stress resulting from lipid peroxidation.

[Hormonal and Metabolic Differences in Patients With Coronary Artery Disease].

OBJECTIVE: To prove the involvement of the autonomic nervous system in the formation of thrombotic status of the patients. 24 patients with myocardial infarction were enrolled in the study. Catecholamines levels were compared duing pain episodes and at rest. Patients were divided in to 2 groups according to the level of norepinephrine during the pain episode: Group 1-12 persons with the level of norepinephrine more than 500 pg/ml, and group 2-12 persons with a level below 500 pg/ml. Patients in group 1 the level of beta thromboglobulin and thromboxane were elevated, as well as there are changes of cAMP and cGMP, indicating increased thrombogenic activity. Particular attention was paid to the 8 patients in Group 1, in which the level of norepinephrine is maintained above 500 pg/ml both during pain and at rest (disseminated intravascular coagulation).

The current and future landscape of urinary thromboxane testing to evaluate atherothrombotic risk.

Biomarker testing for efficacy of therapy is an accepted way for clinicians to individualize dosing to genetic and/or environmental factors that may be influencing a treatment regimen. Aspirin is used by nearly 43 million Americans on a regular basis to reduce risks associated with various atherothrombotic diseases. Despite its widespread use, many clinicians are unaware of the link between suboptimal response to aspirin therapy and increased risk for inferior clinical outcomes in several disease states, and biomarker testing for efficacy of aspirin therapy is not performed as routinely as efficacy testing in other therapeutic areas. This article reviews the clinical and laboratory aspects of determining whole-body thromboxane production, particularly as it pertains to efficacy assessment of aspirin responsiveness.

Association between polyunsaturated fatty acid-derived oxylipid biosynthesis and leukocyte inflammatory marker expression in periparturient dairy cows.

Peripheral blood mononuclear leukocytes from periparturient cows can have exacerbated inflammatory responses that contribute to disease incidence and severity. Oxylipids derived from the oxygenation of polyunsaturated fatty acids (PUFA) can regulate the magnitude and duration of inflammation. Although PUFA substrate for oxylipid biosynthesis in leukocytes is known to change across the periparturient period, the plasma oxylipid profile and how this profile relates to leukocyte inflammatory phenotype is not clear. The objective of this study was to determine if a relationship exists between the profile of pro- and antiinflammatory plasma oxylipids and the inflammatory phenotype of peripheral blood leukocytes during the periparturient period. Seven multiparous Holsteins were sampled from the prepartum period through peak lactation. Plasma oxylipids were measured by liquid chromatography-mass spectrometry, peripheral leukocyte mRNA expression was measured by quantitative PCR, and PUFA content of peripheral blood mononuclear cells was measured by gas chromatography-mass spectrometry. Concentrations of several hydroxyl products of linoleic and arachidonic acid changed over time. Linoleic acid and arachidonic acid concentrations in leukocytes increased during early lactation, suggesting that substrate availability for hydroxyoctadecadienoic and hydroxyeicosatetraenoic acid biosynthesis may influence the oxylipid profile. Leukocyte mRNA expressions of IL-12B, IL-1B, inducible nitric oxide synthase 2, and cyclooxygenase 2 were correlated with several plasma oxylipids. These are the first observations linking leukocyte inflammatory gene responses to shifts in oxylipid biosynthesis in periparturient dairy cows.