Abstract
OKY 046, a specific thromboxane synthase inhibitor, was used to investigate whether large pulmonary emboli, like microemboli, cause an increase in thromboxane A2 and an associated increase in vascular permeability in sheep. Nineteen sheep were anaesthetised and had cannulas inserted into the afferent lymphatic of the caudal mediastinal lymph node and pulmonary and carotid arteries. Several days later the animals were pretreated with placebo or OKY 046 0.4 mg/kg one hour before being given clotted blood 0.5 g/kg intravenously. After embolisation in the control animals mean pulmonary artery pressure (MPAP) rose from 12 to 34 mm Hg and pulmonary artery wedge pressure (PAWP) fell from 4.4 to 1.5 mm Hg; the cardiac index did not change but the physiological shunt (QS/QT) rose from 17% to 50%. One hour after embolisation the platelet count fell from 76 to 32 x 10(6)/l whereas at 15 minutes thromboxane B2 rose from 116 to 560 pg/ml in plasma and from 324 to 795 pg/ml in lymph (p less than 0.05). By 2 hours the concentration of thromboxane B2 was higher in lymph than in plasma. Lymph flow rose from 8.7 to a maximum of 27.3 ml/h at 15 minutes but despite the increase in flow the lymph:plasma (L:P) protein ratio did not fall, indicating an increased permeability of the blood vessels to protein. Pretreatment with OKY 046 inhibited the rise in plasma and lymph thromboxane B2, and limited the rise of QS/QT. The changes in MPAP, PAWP, cardiac index, platelet count, lymph flow, and L:P protein ratio, however, were no different from those in untreated sheep. These results indicate that a large pulmonary embolus leads to an increase in plasma and lung lymph thromboxane A2, which moderates the rise in QS/QT in part but not the increase in vascular permeability.
Full text
PDF




Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Dunham B., Shepro D., Hechtman H. B. Leukotriene induction of TxB2 in cultured bovine aortic endothelial cells. Inflammation. 1984 Sep;8(3):313–321. doi: 10.1007/BF00916419. [DOI] [PubMed] [Google Scholar]
- Garcia-Szabo R. R., Peterson M. B., Watkins W. D., Bizios R., Kong D. L., Malik A. B. Thromboxane generation after thrombin. Protective effect of thromboxane synthetase inhibition on lung fluid balance. Circ Res. 1983 Aug;53(2):214–222. doi: 10.1161/01.res.53.2.214. [DOI] [PubMed] [Google Scholar]
- Hopkins N. K., Sun F. F., Gorman R. R. Thromboxane A2 biosynthesis in human lung fibroblasts WI-38. Biochem Biophys Res Commun. 1978 Nov 29;85(2):827–836. doi: 10.1016/0006-291x(78)91237-8. [DOI] [PubMed] [Google Scholar]
- Huval W. V., Dunham B. M., Lelcuk S., Valeri C. R., Shepro D., Hechtman H. B. Thromboxane mediation of cardiovascular dysfunction following aspiration. Surgery. 1983 Aug;94(2):259–266. [PubMed] [Google Scholar]
- Huval W. V., Mathieson M. A., Stemp L. I., Dunham B. M., Jones A. G., Shepro D., Hechtman H. B. Therapeutic benefits of 5-hydroxytryptamine inhibition following pulmonary embolism. Ann Surg. 1983 Feb;197(2):220–225. doi: 10.1097/00000658-198302000-00016. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lelcuk S., Alexander F., Valeri C. R., Shepro D., Hechtman H. B. Thromboxane A2 moderates permeability after limb ischemia. Ann Surg. 1985 Nov;202(5):642–646. doi: 10.1097/00000658-198511000-00017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lewis R. A., Austen K. F. Mediation of local homeostasis and inflammation by leukotrienes and other mast cell-dependent compounds. Nature. 1981 Sep 10;293(5828):103–108. doi: 10.1038/293103a0. [DOI] [PubMed] [Google Scholar]
- Malik A. B., van der Zee H. Lung vascular permeability following progressive pulmonary embolization. J Appl Physiol Respir Environ Exerc Physiol. 1978 Oct;45(4):590–597. doi: 10.1152/jappl.1978.45.4.590. [DOI] [PubMed] [Google Scholar]
- McDonald J. W., Ali M., Morgan E., Townsend E. R., Cooper J. D. Thromboxane synthesis by sources other than platelets in association with complement-induced pulmonary leukostasis and pulmonary hypertension in sheep. Circ Res. 1983 Jan;52(1):1–6. doi: 10.1161/01.res.52.1.1. [DOI] [PubMed] [Google Scholar]
- Minnear F. L., Johnson A., Malik A. B. Beta-adrenergic modulation of pulmonary transvascular fluid and protein exchange. J Appl Physiol (1985) 1986 Jan;60(1):266–274. doi: 10.1152/jappl.1986.60.1.266. [DOI] [PubMed] [Google Scholar]
- Nachman R. L., Weksler B., Ferris B. Characterization of human platelet vascular permeability-enhancing activity. J Clin Invest. 1972 Mar;51(3):549–556. doi: 10.1172/JCI106843. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ohkuda K., Nakahara K., Weidner W. J., Binder A., Staub N. C. Lung fluid exchange after uneven pulmonary artery obstruction in sheep. Circ Res. 1978 Aug;43(2):152–161. doi: 10.1161/01.res.43.2.152. [DOI] [PubMed] [Google Scholar]
- Schulman E. S., Newball H. H., Demers L. M., Fitzpatrick F. A., Adkinson N. F., Jr Anaphylactic release of thromboxane A2, prostaglandin D2, and prostacyclin from human lung parenchyma. Am Rev Respir Dis. 1981 Oct;124(4):402–406. doi: 10.1164/arrd.1981.124.4.402. [DOI] [PubMed] [Google Scholar]
- Staub N. C., Bland R. D., Brigham K. L., Demling R., Erdmann A. J., 3rd, Woolverton W. C. Preparation of chronic lung lymph fistulas in sheep. J Surg Res. 1975 Nov;19(5):315–320. doi: 10.1016/0022-4804(75)90056-6. [DOI] [PubMed] [Google Scholar]
- Tahamont M. V., Malik A. B. Granulocytes mediate the increase in pulmonary vascular permeability after thrombin embolism. J Appl Physiol Respir Environ Exerc Physiol. 1983 Jun;54(6):1489–1495. doi: 10.1152/jappl.1983.54.6.1489. [DOI] [PubMed] [Google Scholar]
- Utsonomiya T., Krausz M. M., Levine L., Shepro D., Hechtman H. B. Thromboxane mediation of cardiopulmonary effects of embolism. J Clin Invest. 1982 Aug;70(2):361–368. doi: 10.1172/JCI110625. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vaage J., Nicolaysen G., Waaler B. A. Aggregation fo blood platelets and increased hydraulic conductivity of pulmonary exchange vessels. Acta Physiol Scand. 1976 Oct;98(2):175–184. [PubMed] [Google Scholar]
- Weksler B. B., Ley C. W., Jaffe E. A. Stimulation of endothelial cell prostacyclin production by thrombin, trypsin, and the ionophore A 23187. J Clin Invest. 1978 Nov;62(5):923–930. doi: 10.1172/JCI109220. [DOI] [PMC free article] [PubMed] [Google Scholar]
