Stroma free human platelet lysates potentiate the in vivo thrombogenicity of factor Xa by the provision of coagulant-active phospholipid.
A stroma free platelet lysate supernatant (PLS) was prepared by repeatedly freezing and thawing a human platelet suspension separated from platelet rich plasma by gel filtration. The material was potently thrombogenic in a stasis model in rabbits, but only when combined with a purified preparation of factor Xa. The dose of factor Xa used was not thrombogenic when given alone. Initial evaluation suggested the presence of a factor V activator when PLS shortened the clotting time of normal but not a V deficient plasma. Subsequent evaluation, in a system employing purified components of the prothrombinase complex and a marker of thrombin generation, dansyl-arginine-N-(3-ethyl-1,5-pentanediyl)amide (DAPA), failed to confirm the presence of a factor V activator. Further evaluation in this system demonstrated that the procoagulant activity related to the content of coagulant-active phospholipid. Thin layer chromatography confirmed the presence of phospholipids known to have coagulant activity. These components were isolated by a lipid extraction procedure and the phospholipid replacing activity in the in vitro assay with DAPA was quantitatively retained. The extracted material was non-thrombogenic in vivo but augmented the thrombogenicity of a purified preparation of Xa.
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives; D001777:Blood Coagulation / Q000187:drug effects*; D001792:Blood Platelets; D002855:Chromatography, Thin Layer; D003619:Dansyl Compounds; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005165:Factor V / Q000032:analysis; D015943:Factor Va; D005170:Factor X / Q000494:pharmacology*; D015951:Factor Xa; D005470:Fluorometry; D006801:Humans; D008297:Male; D010743:Phospholipids / Q000302:isolation & purification*; D011817:Rabbits; D013917:Thrombin / Q000096:biosynthesis
D003619:Dansyl Compounds; D010743:Phospholipids; C019162:dansylarginine N-(3-ethyl-1,5-pentanediyl)amide; D015943:Factor Va; D005165:Factor V; D005170:Factor X; D001120:Arginine; D013917:Thrombin; D015951:Factor Xa