The influence of venous occlusion on the status of protein S.
In the present study the effect of perturbation of the vessel wall by venous occlusion on protein S release, was evaluated in 10 healthy male volunteers. A 9% (P less than 0.01) increase in free protein S and a 7% (NS) in total protein S over the baseline were observed 7 min after venous occlusion, whereas von Willebrand factor antigen (vWF:Ag)--a known release product of vascular endothelium--increased by 11% (P less than 0.01). In addition, the possibility of free protein S release from unstimulated platelets was investigated in pre- and post-occlusion samples incubated at room temperature for 24 h as whole blood or platelet-rich plasma. An increase in the mean free protein S was observed in the pre-occlusion samples which peaked after 4 h of incubation--121% at time 0 to 130% (P less than 0.05) of the normal pooled plasma whereas total protein S increased by only 4% (NS). In the post-occlusion samples, a similar peak in mean free protein S levels was observed after 12 h of incubation--132% at time 0 increased to 142% (P less than 0.01) of the normal human plasma pooled and the total protein S was increased by 8.55 (P less than 0.05). Small but significant increases in vWF:Ag levels were observed at 2 h and 6 h for the pre- and post-occlusion samples, respectively. No changes in C4b-binding protein were observed throughout the study. We conclude that, firstly, venous occlusion causes release of protein S in addition to vWF:Ag and, secondly, unstimulated platelets release protein S in addition to vWF:Ag.
Monte
G
G
Thrombosis Research Institute, Chelsea, London, UK.
Lindo
V S
VS
Radicchia
S
S
Melissari
E
E
Kakkar
V V
VV
D000293:Adolescent; D000328:Adult; D000941:Antigens / Q000097:blood; D001792:Blood Platelets / Q000378:metabolism; D001798:Blood Proteins / Q000378:metabolism*; D015935:Complement C4b / Q000378:metabolism; D003250:Constriction; D004730:Endothelium, Vascular / Q000378:metabolism*; D005260:Female; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D017293:Protein S; D013927:Thrombosis / Q000097:blood; D014680:Veins / Q000502:physiology*; D014841:von Willebrand Factor / Q000276:immunology
D000941:Antigens; D001798:Blood Proteins; D006023:Glycoproteins; D017293:Protein S; C029417:Von Willebrand antigen; D014841:von Willebrand Factor; D015935:Complement C4b