Abstract | OBJECT: Platelet isoprostane 8-ISO-prostaglandin F2α (8-iso-PGF2α), a proaggregating molecule, is believed to derive from nonenzymatic oxidation of arachidonic acid. We hypothesized that NADPH is implicated in isoprostane formation and platelet activation. METHODS AND RESULTS: We studied 8-iso-PGF2α in platelets from 8 male patients with hereditary deficiency of gp91( phox), the catalytic subunit of NADPH oxidase, and 8 male controls. On stimulation, platelets from controls produced 8-iso-PGF2α, which was inhibited -8% by aspirin and -58% by a specific inhibitor of gp91( phox). Platelets from patients with gp91( phox) hereditary deficiency had normal thromboxane A(2) formation but marked 8-iso-PGF2α reduction compared with controls. In normal platelets incubated with a gp91( phox) inhibitor or with SQ29548, a thromboxane A(2)/isoprostane receptor inhibitor, platelet recruitment, an in vitro model of thrombus growth, was reduced by 44% and 64%, respectively; a lower effect (-17%) was seen with aspirin. Moreover, thrombus formation under shear stress (blood perfusion at the wall shear rate of 1500 s(-1)) was reduced in samples in which isoprostane formation was inhibited by NADPH oxidase inhibitors. In gp91(phox)-deficient patients, agonist-induced platelet aggregation was within the normal range, whereas platelet recruitment was reduced compared with controls. Incubation of platelets from gp91(phox)-deficient patients with 8-iso-PGF2α dose-dependently (1 to 100 pmol/L) increased platelet recruitment by mobilizing platelet Ca(2+) and activating gpIIb/IIIa; a further increase in platelet recruitment was detected by platelet coincubation with l-NAME, an inhibitor of NO synthase. CONCLUSIONS: This study provides the first evidence that platelet 8-iso-PGF2α maximally derives from gp91( phox) activation and contributes to platelet recruitment via activation of gpIIb/IIIa.
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Authors | Pasquale Pignatelli, Roberto Carnevale, Serena Di Santo, Simona Bartimoccia, Valerio Sanguigni, Luisa Lenti, Andrea Finocchi, Loredana Mendolicchio, Anna Rosa Soresina, Alessandro Plebani, Francesco Violi |
Journal | Arteriosclerosis, thrombosis, and vascular biology
(Arterioscler Thromb Vasc Biol)
Vol. 31
Issue 2
Pg. 423-34
(Feb 2011)
ISSN: 1524-4636 [Electronic] United States |
PMID | 21071703
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Enzyme Inhibitors
- Isoprostanes
- Membrane Glycoproteins
- Platelet Aggregation Inhibitors
- Platelet Glycoprotein GPIIb-IIIa Complex
- 8-epi-prostaglandin F2alpha
- NADP
- Dinoprost
- Nitric Oxide Synthase
- CYBB protein, human
- NADPH Oxidase 2
- NADPH Oxidases
- Aspirin
- Calcium
- NG-Nitroarginine Methyl Ester
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Topics |
- Adult
- Aspirin
(pharmacology)
- Blood Platelets
(cytology, drug effects, metabolism)
- Calcium
(metabolism)
- Case-Control Studies
- Deficiency Diseases
(metabolism, pathology)
- Dinoprost
(analogs & derivatives, pharmacology)
- Dose-Response Relationship, Drug
- Enzyme Inhibitors
(pharmacology)
- Humans
- Isoprostanes
(metabolism)
- Male
- Membrane Glycoproteins
(antagonists & inhibitors, deficiency, genetics)
- NADP
(metabolism)
- NADPH Oxidase 2
- NADPH Oxidases
(antagonists & inhibitors, deficiency, genetics)
- NG-Nitroarginine Methyl Ester
(pharmacology)
- Nitric Oxide Synthase
(antagonists & inhibitors)
- Platelet Aggregation Inhibitors
(pharmacology)
- Platelet Glycoprotein GPIIb-IIIa Complex
(metabolism)
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