[Study on platelet-associated tissue factor and its significance].
OBJECTIVE
To explore whether normal platelet contains tissue factor (TF), and the significance of platelet-associated TF (PATF).


METHODS
Platelets were isolated by Sepharose 2B gel column. ELISA was used to detect the TF content in the lysates of washed platelets. Procoagulant activity of PATF was measured by one stage clotting time assay. The mRNA of TF was detected by reverse transcription polymerase chain reaction (RT-PCR).


RESULTS
A certain amount of TF antigen (16.37 +/- 6.39) ng/L was detected in the washed-platelet lysates. Upon activation by collagen, platelets released TF and caused a marked increase in TF level in plasma (P <0.05). Resting platelets had no TF procoagulant activity, while procoagulant activity of platelets activated by collagen increased significantly, which could be blocked by TF McAb and poor VII plasma. TF mRNA could not be detected in washed platelets. TF content in platelets from patients with coronary heart disease was significantly higher than that from normal controls (P < 0.05). Resting platelets from the patients showed a higher procoagulant activity, which could be inhibited by TF McAb.


CONCLUSIONS
Platelets contain TF and the latter released by activated platelet was functionally active. Platelet itself might not synthesize TF. Protein content and procoagulant activity of PATF in patients with coronary heart disease were higher than that in controls. All these indicate that platelet may be involved in coagulation and thrombosis by releasing TF.
Department of Hematology, Xiangya Hospital, Central Southern University, Changsha, China.
Xi-lian
XL
Huang
Fang-ping
FP
Chen
Jian-wei
JW
Du
Min-yuan
MY
Peng
Bin
B
Fu
Qin-zhi
QZ
Xie
Shi-lin
SL
He
D000293:Adolescent; D000328:Adult; D001792:Blood Platelets / Q000737:chemistry*; D003324:Coronary Artery Disease / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation; D013925:Thromboplastin / Q000378:metabolism / Q000502:physiology*
D013925:Thromboplastin