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Impaired antiplatelet effects of aspirin associated with hypoxia and ATP release from erythrocytes. Studies in a system with flowing human blood
Author(s) -
J. Bozzo,
Marı́a Rosa Hernández,
Ana M. Galán,
Magda Heras,
Antonio Ordinas,
Ginés Escolar
Publication year - 1999
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1046/j.1365-2362.1999.00483.x
Subject(s) - apyrase , aspirin , platelet , hypoxia (environmental) , thrombus , chemistry , whole blood , perfusion , pharmacology , medicine , endocrinology , biochemistry , oxygen , organic chemistry
Background We have explored how hypoxic conditions may affect the antiplatelet effects of aspirin. Materials and methods For this purpose, a perfusion system containing a damaged vessel segment was modified in order to induce hypoxia (low P o 2 ) in flowing blood. Blood samples were incubated with 50 μmol L −1 aspirin and divided into two aliquots, one being perfused under standard conditions (normoxic) and the other under hypoxic conditions. The interaction of platelets with the subendothelium was morphometrically evaluated. Results In studies with untreated blood under normoxic conditions, platelet interaction with the subendothelium was 0.3 ± 0.1% of contact, 5.3 ± 1.6% of adhesion, 24.3 ± 3.3% of thrombus and 29.9 ± 2.7% of total covered surface. Aspirin‐treated blood perfused under normoxic conditions showed a marked decrease in thrombus with a concomitant increase in both platelet adhesion and covered surface percentages. However, when aspirin‐treated blood was perfused under hypoxic conditions, platelet interaction was not significantly different from that observed in untreated blood. Hypoxia induced a 10‐fold increase in ATP release from erythrocytes in the perfusates. If apyrase was added to the perfusates, ATP release was prevented and aspirin effects were evident again. Conclusion Our results suggest that, under hypoxic conditions, the presence of aspirin would not help to inhibit further platelet activation.