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Background: Inflammation, oxidative damage, and platelet activation are hypothesized biological mechanisms driving the disablement process. The aim of the present study is to assess whether biomarkers representing these mechanisms predicted major adverse health-related events in older persons.Methods: Data are from 2,234 community-dwelling nondisabled older persons enrolled in the Health Aging and Body Composition study. Biomarkers of lipid peroxidation (ie, urinary levels of 8-iso-prostaglandin F(2α)), platelet activation (ie, urinary levels of 11-dehydro-thromboxane B(2)), and inflammation (serum concentrations of interleukin-6) were considered as independent variables of interest and tested in Cox proportional hazard models as predictors of (severe) mobility disability and overall mortality.Results: The sample's (women 48.0%, whites 64.3%) mean age was 74.6 (SD 2.9) years. During the follow-up (median 11.4 years), 792 (35.5%), 269 (12.0%), and 942 (42.2%) events of mobility disability, severe mobility disability, and mortality occurred, respectively. Only interleukin-6 showed significant independent associations with the onset of all the study outcomes. Higher levels of urinary 8-iso-prostaglandin F(2α) and 11-dehydro-thromboxane B(2) independently predicted increased risk of death (hazard ratio 1.10, 95% confidence interval 1.03-1.19 and hazard ratio 1.14, 95% confidence interval 1.06-1.23, respectively). No significant interactions of gender, race, cardiovascular disease, diabetes, and antiplatelet drugs were detected on the studied relationships.Conclusions: The inflammatory marker interleukin-6 is confirmed to be a robust predictor for the onset of negative health-related events. Participants with higher urinary levels of 8-iso-prostaglandin F(2α) and 11-dehydro-thromboxane B(2) presented a higher mortality risk. [ABSTRACT FROM AUTHOR]

Conventional medical treatment for rheumatoid arthritis and osteoarthritis includes the use of NSAIDs (traditional and selective inhibitors of cyclooxygenase [COX]-2), because they provide unmistakable and significant health benefits in the treatment of pain and inflammation. However, they are associated with an increased risk of serious gastrointestinal (GI) and cardiovascular (CV) adverse events. Both beneficial and adverse effects are due to the same mechanism of action, which is inhibition of COX-dependent prostanoids. Since CV and GI risk are related to drug exposure, a reduction in the administered dose is recommended. However, this strategy will not eliminate the hazard owing to a possible contribution of individual genetic background. Further studies will be necessary to develop genetic and/or biochemical markers predictive of the CV and GI risk of NSAIDs. [ABSTRACT FROM AUTHOR]

The article focuses on a study which assessed the risk of upper gastrointestinal (GI) bleeding/perforation among users of individual nonsteroidal anti-inflammatory drugs (NSAIDs) and analyzed the correlation between the risk and the degree of inhibition of whole blood cyclooxygenase 1 (COX-1) and COX-2 in vitro. Observational studies on NSAIDs and upper GI bleeding perforation published between 2000 and 2008 were reviewed. Results revealed that the risk varies between individual NSAIDs at the doses commonly used in the general population.

The article presents a study which examines the importance of COX-2-dependent prostanoids induction in the endothelial cells through laminar shear stress (LSS). Result of the study shows that LSS-dependent reduction of TNF-α generation and heme oxygenase (HO)-1 induction were abolished by the selective inhibitor of COX-2. It indicates that COX-2 prostaglandin inhibition contribute to acceleration of atherogenesis in patients taking traditional nonsteroidal antiinflammatory drugs (NSAIDS).

Background and Objective: We performed a placebo-controlled, randomized study to address whether celecoxib or ibuprofen undermines the functional range of inhibition of platelet cyclooxygenase (COX)–1 activity by aspirin in patients with osteoarthritis and stable ischemic heart disease.Methods: Twenty-four patients who were undergoing long-term treatment with aspirin (100 mg daily) for cardioprotection were coadministered celecoxib, 200 mg twice daily, ibuprofen, 600 mg 3 times daily, or placebo for 7 days.Results: The coadministration of placebo or celecoxib did not undermine the aspirin-related inhibition of platelet COX-1 activity, as assessed by measurements of serum thromboxane B2 (TXB2) levels, as well as platelet function. In contrast, a significant (P < .001) increase in serum TXB2 level was detected on day 7 before drug administration (median, 19.13 ng/mL [range, 1-47.5 ng/mL]) and at 24 hours after the coadministration of aspirin and ibuprofen (median, 22.28 ng/mL [range, 4.9-44.4 ng/mL]) versus baseline (median, 1.65 ng/mL [range, 0.55-79.8 ng/mL]); this was associated with a significant increase in arachidonic acid–induced platelet aggregation (P < .01) and adenosine diphosphate–induced platelet aggregation (P < .05) and a decrease in the time to form an occlusive thrombus in the platelet function analyzer (P < .01). The urinary excretion of 11-dehydro-TXB2, an index of systemic thromboxane biosynthesis, was not significantly affected by the coadministration of treatment drugs. At steady state, a comparable and persistent inhibition of lipopolysaccharide-stimulated prostaglandin E2 generation, a marker of COX-2 activity ex vivo, was caused by ibuprofen (≥80%) or celecoxib (≥70%) but not placebo.Conclusions: Unlike ibuprofen, celecoxib did not interfere with the inhibition of platelet COX-1 activity and function by aspirin despite a comparable suppression of COX-2 ex vivo in patients with osteoarthritis and stable ischemic heart disease.Clinical Pharmacology & Therapeutics (2006) 80, 264–274; doi: 10.1016/j.clpt.2006.05.004 [ABSTRACT FROM AUTHOR]

Background and Objectives: Complete and persistent suppression of platelet thromboxane (TX) A2 biosynthesis by aspirin is mandatory to fulfill its cardioprotection. We explored the determinants of heterogeneity of TXB2 generation in clotting whole blood, a capacity index of platelet cyclooxygenase (COX) activity, in patients with coronary heart disease (CHD) versus healthy subjects treated with low-dose aspirin on a long-term basis.Methods: We studied 30 patients with CHD (ie, chronic stable angina, unstable angina, and acute myocardial infarction) and 10 healthy subjects, who were treated with low-dose aspirin (100 mg daily) on a long-term basis, 12 hours after the administration of 160 mg aspirin to ensure saturation of platelet COX-1 activity. Serum TXB2 levels were assessed. The contribution of blood COX-2 to TXA2 biosynthesis was explored by evaluation of the effect of a selective COX-2 inhibitor (L-745,337) added to heparinized whole blood stimulated with Ca++ ionophore A23187 (20 μmol/L) for 1 hour or lipopolysaccharide (0.1 μg/mL) for 4 hours.Results: In healthy subjects serum TXB2 levels ranged from 0.6 to 7.9 ng/mL (median, 2.1 ng/mL; mean ± SD, 3.2 ± 2.6 ng/mL). In CHD patients we detected enhanced variability in serum TXB2 generation (median, 3.1 ng/mL [range, 0.15-47 ng/mL]; mean, 8.5 ± 12.3 ng/mL), which in 8 patients (27%) exceeded the mean value + 2 SDs detected in healthy subjects (ie, 8.4 ng/mL), set as the limit value for an adequate inhibition of platelet COX-1 by aspirin. Elevated whole-blood TXB2 generation was not dependent on leukocyte count, COX-2 activity, or cigarette smoking but was plausibly a result of defective suppression of platelet COX-1 activity.Conclusions: Heterogeneity in the suppression of platelet COX-1 activity by aspirin occurred in CHD patients. The measurement of the serum TXB2 level seems to be an appropriate biomarker to identify patients who have an inadequate inhibition of platelet COX-1 activity by aspirin.Clinical Pharmacology & Therapeutics (2006) 80, 115–125; doi: 10.1016/j.clpt.2006.04.011 [ABSTRACT FROM AUTHOR]

Inhibition of platelet cyclooxygenase (COX)-1 is involved in aspirin cardioprotection observed in clinical trials, but, in some patients, aspirin is unable to protect from thrombotic complications. An incomplete suppression of platelet thromboxane (TX) A2 biosynthesis has been assumed to participate in the phenomenon of aspirin resistance, as a consequence of the following possible mechanisms: (i) COX-2 expression in newly formed platelets; (ii) pharmacodynamic interactions between aspirin and coadministered nonsteroidal antiinflammatory drugs (e.g. ibuprofen); (iii) expression of variant isoforms of COX-1 with reduced sensitivity to irreversible inactivation at Ser529. Furthermore, aspirin failure may be due to enhanced formation of vasoactive and/or proaggregatory eicosanoids despite an almost complete suppression of platelet TXA2 biosynthesis by aspirin. Thus, in a subset of patients with unstable angina treated with low-dose aspirin, to almost completely block platelet COX-1 activity, enhanced TXA2 biosynthesis in vivo has been demonstrated, presumably through an increased generation of COX-2-dependent PGH2 in plaque monocytes/macrophages or activated vascular cells. The concomitant increased formation of 8-iso-PGF2α, one of the most abundant F2-isoprostanes in humans, generated by free-radical catalyzed arachidonate peroxidation, may be involved in aspirin resistance because of its capacity to induce platelet and vascular smooth muscle cell activation through the interaction with thromboxane receptors (TPs). Finally, enhanced production of vasoactive cysteinyl leukotrienes (cys-LTs) occurs in unstable angina despite conventional antithrombotic and antianginal treatment. The use of selective pharmacological tools (i.e. highly selective COX-2 inhibitors, TP antagonists, cys-LT inhibitors and antagonists) will allow to ascertain the contribution of aspirin insensitive eicosanoid biosynthesis in aspirin cardioprotective failure. [Copyright &y& Elsevier]