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Research Article Free access | 10.1172/JCI110824
1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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1Division of Nephrology and Dialysis, Ospedali Riuniti di Bergamo, Istituto di Ricerche Farmacologiche “Mario Negri”, 20157 Milano, Italy
2Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824
Department of Pharmacology, Catholic University School of Medicine, 00168 Rome, Italy
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Published March 1, 1983 - More info
A qualitative platelet abnormality and a bleeding tendency are frequently associated with renal failure and uremia. We demonstrated previously that uremic patients display an abnormal platelet aggregation to arachidonic acid and reduced malondialdehyde production in response to thrombin and arachidonic acid. The objectives of this investigation were: (a) to compare platelet prostaglandin (PG) and thromboxane (TX) production in whole blood and in platelet-rich plasma (PRP) of 21 uremic patients and 22 healthy subjects; (b) to evaluate the concentration and activity of platelet PG- and TX-forming enzymes; (c) to assess the functional responsiveness of the platelet TXA2/PGH2 receptor; (d) to explore the hemostatic consequences of partially reduced TXA2 production.
Platelet immunoreactive TXB2 production during whole blood clotting was significantly reduced, by ∼60%, in uremic patients as compared to age- and sex-matched controls. Exogenous thrombin (5-30 IU/ml) failed to restore normal TXB2 production in uremic platelets. Uremic PRP produced comparable or slightly higher amounts of TXB2 than normal PRP at arachidonate concentrations 0.25-1 mM. However, when exposed to substrate concentrations >2 mM, uremic PRP produced significantly less TXB2 than normal PRP. To discriminate between reduced arachidonic acid oxygenation and altered endoperoxide metabolism, the time course of immunoreactive TXB2 and PGE2 production was measured during whole blood clotting. The synthesis and release of both cyclooxygenase-derived products was slower and significantly reduced, at all time intervals considered. Furthermore, PGI2 production in whole blood, as reflected by serum immunoreactive 6-keto-PGF1α concentrations, was significantly reduced in uremic patients as compared with healthy subjects. PGH synthase levels, as determined by an immunoradiometric assay, were not significantly different in platelets from uremic patients as compared to control platelets. A single 40-mg dose of aspirin given to five healthy volunteers reduced their serum TXB2 to levels found in uremic patients. This was associated with a significant increase of threshold aggregating concentrations of ADP and arachidonic acid and prolongation of bleeding time. Substantially similar threshold concentrations of U46619, a TXA2 agonist, induced aggregation of normal and uremic platelets. Prostacyclin induced a significant elevation of uremic platelet cyclic AMP, which was suppressed by U46619, further suggesting normal responsiveness of the TXA2/PGH2 receptor.
We conclude that: (a) an abnormality of platelet arachidonic acid metabolism exists in uremia, leading to a reduced TXA2 production; (b) the characteristics of this abnormality are consistent with a functional cyclooxygenase defect; (c) reduced TXA2 production may partially explain the previously described abnormality of platelet function in uremia.