Antigen levels of plasminogen activator inhibitor type 1 in citrated plasma: determination of the contribution of platelets.
To estimate the extent of the release of plasminogen activator inhibitor type 1 (PAI-1) from platelets following their accidental activation in vitro during blood collection, we studied the antigen levels of PAI-1 and beta-thromboglobulin (beta TG) in plasma and sera from 38 healthy volunteers. For each volunteer, we calculated the ratio of platelet-derived PAI-1/platelet-derived beta TG from the difference in their respective concentrations in serum and plasma. The mean +/- SD (0.012 +/- 0.003) and median (0.012) ratios were identical before and after 10 or 20 min of venous occlusion. The platelet contribution of PAI-1 in plasma was estimated by multiplying the plasma concentration of beta TG (as a marker of platelet activation) with the above-mentioned individual ratio. Under our conditions of blood collection (1/10 vol of 0.1 M citrate, pH 4.5, as anticoagulant, and handling of blood at 4 degrees C and within 30 min), the platelet contribution to the PAI-1 concentration in plasma was on average 12% and always negligible in plasma with high levels of PAI-1.
Grimaudo
V
V
Department of Medicine, University Hospital Center, Lausanne, Switzerland.
Bachmann
F
F
Kruithof
E K
EK
D000328:Adult; D015415:Biomarkers / Q000097:blood; D001792:Blood Platelets / Q000378:metabolism*; D002951:Citrates; D019343:Citric Acid; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010949:Plasma / Q000737:chemistry; D015849:Plasminogen Inactivators / Q000097:blood*; D011863:Radioimmunoassay; D013048:Specimen Handling; D001620:beta-Thromboglobulin / Q000032:analysis*
D015415:Biomarkers; D002951:Citrates; D015849:Plasminogen Inactivators; D001620:beta-Thromboglobulin; D019343:Citric Acid