Linked Life Data

7579397

Source:http://linkedlifedata.com/resource/pubmed/id/7579397

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1995-11-29
pubmed:abstractText
Recently, an alternative pathway for factor XI activation has been described in which factor XI is activated by thrombin. Patients with a factor XI deficiency bleed mostly from tissues with high local fibrinolytic activity. Therefore, the role of thrombin-mediated factor XI activation in both fibrin formation and fibrinolysis was studied in a plasma system. Clotting was induced by the addition of tissue factor or thrombin to recalcified plasma in the presence or absence of tissue-type plasminogen activator, after which clot formation and lysis were measured using turbidimetry. Thrombin-mediated activation of factor XI was found to take place in plasma under physiologic conditions in the absence of a dextran sulfate-like cofactor. At high tissue factor concentrations, no effect of factor XI was seen on the rate of fibrin formation. Decreasing amounts of tissue factor resulted in a gradually increasing contribution of factor XI to the rate of fibrin formation. In addition, thrombin-mediated factor XI activation resulted in an inhibition of tissue-type plasminogen activator-induced lysis of the clot. This inhibition occurred even at tissue factor concentrations at which no effect of factor XI was observed on fibrin formation. Trace amounts of activated factor XI (1.25 pmol/L, representing 0.01% activation) were capable of completely inhibiting fibrinolysis in our system. The inhibitory effect was found to be mediated by thrombin that is additionally generated in a factor XI-dependent manner via the intrinsic pathway and is capable of protecting the clot against lysis. We also observed that formation of additional thrombin continued after the clot had been formed. We conclude that thrombin-mediated factor XI activation can take place in plasma. The presence of factor XI during coagulation results in the formation of additional thrombin within the clot capable of protecting this clot from fibrinolytic attack. The large amounts of thrombin that are formed by the intrinsic pathway via factor XI may play an important role in the procoagulant and thrombogenic state of clots and may therefore have important clinical and therapeutic implications.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-4971
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
86
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3035-42
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Feedback activation of factor XI by thrombin in plasma results in additional formation of thrombin that protects fibrin clots from fibrinolysis.
pubmed:affiliation
Department of Haematology, University Hospital Utrecht, The Netherlands.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't