Document Detail


Systemic levels and preportal organ release of tissue-type plasminogen activator are enhanced by PEEP in the pig.
MedLine Citation:
PMID:  10408816     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Endothelium-derived tissue-type plasminogen activator, t-PA, is the key enzyme in the initiation of endogenous thrombolysis. Plasma levels of t-PA increase in response to sympatho-adrenergic activation. In the mesenteric vascular bed an increased norepinephrine spillover has been observed during positive end-expiratory pressure ventilation, PEEP. This experimental study examines the effects of PEEP-induced alterations on regional release rates and systemic levels of t-PA in vivo. METHODS: The protocol included measurements of arterio-venous concentration gradients of t-PA and the respective plasma flow across the pulmonary, coronary, hepatic and preportal vascular beds, in pigs, during zero-PEEP and at 2, 4 and 10 min after the application of a PEEP of 10 cm H2O. Both total plasma t-PA antigen (ELISA with a porcine t-PA standard) and active t-PA (spectrophotometric functional assay) were determined. RESULTS: During zero-PEEP, a high preportal basal net release and hepatic net uptake of total t-PA was observed. With PEEP, the magnitude of the preportal net release of t-PA was markedly enhanced (+24+/-5%), as was hepatic net uptake (+21+/-8%), simultaneously to a significant decrease in liver plasma flow (-30+/-2%). PEEP-induced alterations in active t-PA mirrored those observed in total t-PA. No significant net fluxes of total or active t-PA were observed across the coronary or the pulmonary vascular beds. CONCLUSIONS: Clinically used levels of PEEP induce increases in net release of endothelially derived t-PA within preportal organs. The application of PEEP is associated with increased systemic levels of total and active t-PA, in spite of a simultaneous increase in hepatic net uptake, indicating that the preportal vascular bed can not account for the systemic t-PA response.
Authors:
H Seeman-Lodding; S Häggmark; C Jern; S Jern; G Johansson; O Winsö; B Biber
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Acta anaesthesiologica Scandinavica     Volume:  43     ISSN:  0001-5172     ISO Abbreviation:  Acta Anaesthesiol Scand     Publication Date:  1999 Jul 
Date Detail:
Created Date:  1999-10-08     Completed Date:  1999-10-08     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370270     Medline TA:  Acta Anaesthesiol Scand     Country:  DENMARK    
Other Details:
Languages:  eng     Pagination:  623-33     Citation Subset:  IM    
Affiliation:
Department of Anesthesiology and Intensive Care, Sahlgrenska University Hospital, Göteborg, Sweden.
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MeSH Terms
Descriptor/Qualifier:
Animals
Aorta
Coronary Vessels
Hemodynamics
Hepatic Veins
Liver / metabolism
Lung / metabolism
Myocardium / metabolism
Portal Vein
Positive-Pressure Respiration*
Pulmonary Artery
Swine
Tissue Plasminogen Activator / blood,  metabolism*
Veins
Chemical
Reg. No./Substance:
EC 3.4.21.68/Tissue Plasminogen Activator

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