Eicosanoid biosynthesis in patients with stable angina: Beneficial effects of very low dose aspirin

AbstractObjectives. We assessed the production of eicosanoids and the effects of very low dose aspirin in patients with stable angina under basal conditions and during rapid atrial pacing.Background. Platelet activation occurs in acute ischemic syndromes but is still controversial in stable angina. Very low dose aspirin is known to be platelet selective and can be used to test the hypothesis of the platelet origin of increased thromboxane production in stable angina.Methods. Urinary excretion of eicosanoids was measured in 42 patients, including 24 patients with and 18 patients without coronary artery disease. The effects of 50 mg/day of aspirin were measured at rest and during pacing-induced ischemia in 10 patients with stable angina and were compared with a similar group of patients not treated by aspirin.Results. Excretion of 11-dehydro-thromboxane B2was 2.6 times higher in patients with stable angina than in healthy subjects (mean [±SEM] 74.8 ± 13.0 [24 patients] vs. 29.0 ± 5.4 [18 patients] ng/mmol of creatinine, p < 0.01). Urinary prostacyclin metabolite levels did not differ between the two groups. Treatment for 8 days with 50 mg/day of aspirin inhibited platelet cyclooxygenase, as reflected by the 97% reduction of in vitro serum thromboxane production. This aspirin regimen normalized the level of urinary thromboxane metabolites in patients with angina (17.3 ± 3.4 ng/mmol of creatinine [10 patients], p < 0.001 from baseline level before treatment) and did not change prostacyclin metabolite levels. Atrial pacing in patients with angina not treated with aspirin caused lactate and thromboxane release into the coronary sinus. In patients with very low dose aspirin therapy, pacing did not cause thromboxane release despite inducing myocardial ischemia. However, fractional lactate extraction decreased less sharply in patients with than without aspirin therapy.Conclusions. Thromboxane production is greatly increased in patients with stable angina. Very low dose aspirin administered to these patients reduces thromboxane synthesis to normal levels, preserves prostacyclin biosynthesis and prevents acute thromboxane release into the coronary circulation during pacing-induced ischemia. Our data suggest that platelets (not monocytes/ macrophages) are activated in stable angina to produce thromboxane

Cellular and collagen reference values of gingival and periodontal ligament tissues in rats: a pilot study

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FTIR microscopy contribution for comprehension of degradation mechanisms in PLA-based implantable medical devices

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Devising tissue ingrowth metrics: a contribution to the computational characterization of engineered soft tissue healing

International audienceThe paradigm shift brought about by the expansion of tissue engineering and regenerative medicine away from the use of biomaterials, currently questions the value of histopathologic methods in the evaluation of biological changes. To date, the available tools of evaluation are not fully consistent and satisfactory for these advanced therapies.Wehave developed a new, simple and inexpensive quantitative digital approach that provides key metrics for structural and compositional characterization of the regenerated tissues. For example, metrics provide the tissue ingrowth rate (TIR) which integrates two separate indicators; the cell ingrowth rate (CIR) and the total collagen content (TCC) as featured in the equation, TIR%=CIR%+TCC%. Moreover a subset of quantitative indicators describing the directional organization of the collagen (relating structure and mechanical function of tissues), the ratio of collagen I to collagen III (remodeling quality) and the optical anisotropy property of the collagen (maturity indicator) was automatically assessed as well. Using an image analyzer, all metrics were extracted from only two serial sections stained with either Feulgen&Rossenbeck (cell specific) or Picrosirius Red F3BA (collagen specific). To validate this new procedure, threedimensional(3D) scaffolds were intraperitoneally implanted in healthy and in diabetic rats. It was hypothesized that quantitatively, the healing tissue would be significantly delayed and of poor quality in diabetic rats in comparison to healthy rats. In addition, a chemically modified 3D scaffold wassimilarly implanted in a third group of healthy rats with the assumption that modulation of the ingrown tissue would be quantitatively present in comparison to the 3D scaffold-healthy group. After 21 days of implantation, both hypotheses were verified by use of this novel computerized approach. When the two methods were run in parallel, the quantitative results revealed fine details and differences not detected by the semi-quantitative assessment, demonstrating the importance of quantitative analysis in the performance evaluation of soft tissue healing. This automated and supervised method reduced operator dependency and proved to be simple, sensitive, cost-effective and time-effective. It supports objective therapeutic comparisons and helps to elucidate regeneration and the dynamics of a functional tissue

Etude de la depolarisation myocardique epicardique chez l'homme au cours de la tachycardie ventriculaire chronique par reentree, et lors du syndrome de Wolff-Parkinson-White

SIGLECNRS AR 10519 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc