PubMed · 11364061
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1996-12-27. Settlement postponed.. https://pubmed.ncbi.nlm.nih.gov/11364061/
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In the present study we investigated whether endothelial microparticles (EMPs) can bind to monocytic THP-1 cells and modulate their procoagulant properties. Using flow cytometry, we demonstrated that EMPs express adhesive receptors similar to those expressed by activated endothelial cells. Expression of endothelial antigens by THP-1 cells incubated with EMP was shown by immunoperoxidase staining and flow cytometry using antibodies directed against E-selectin, VCAM-1, and endoglin. EMP binding to THP-1 cells was time- and concentration- dependent, reached a plateau at 15 minutes, and had an EMP-to-monocyte ratio of 50:1. EMP binding was not affected by low temperature and was not followed by the restoration of phosphatidylserine asymmetry, suggesting that adhesion was not followed by fusion. A 4-hour incubation of THP-1 cells with EMP led to an increase in procoagulant activity as measured by clotting assay. Concomitantly, THP-1 exhibited increased levels of tissue factor (TF) antigen and TF mRNA compared to control cells. The ability of EMP to induce THP-1 procoagulant activity was significantly reduced when THP-1 cells were incubated with EMP in the presence of blocking antibodies against ICAM-1 and beta2 integrins. These results demonstrate that EMPs interact with THP-1 cells in vitro and stimulate TF-mediated procoagulant activity that is partially dependent on the interaction of ICAM-1 on EMP and its counterreceptor, beta2 integrins, on THP-1 cells. Induction of procoagulant activity was also demonstrated using human monocytes, suggesting a novel mechanism by which EMP may participate in the dissemination and amplification of procoagulant cellular responses.
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PURPOSE: Modified ultrafiltration (MUF) after cardiopulmonary bypass (CPB) in children has been reported to reduce the need for postoperative blood transfusion and minimize postoperative blood loss. This study was undertaken to quantify the effects of MUF on coagulation factors in pediatric patients. METHODS: Seven children scheduled to undergo open-heart surgery for congenital heart defects were studied. CPB circuits were primed with crystalloid solutions and no blood transfusions were performed. Hematocrit, platelet count, total plasma proteins, albumin, fibrinogen, prothrombin, factor VII, factor IX, and factor X were measured preoperatively, at the termination of cardiopulmonary bypass, and at the end of modified ultrafiltration. RESULTS: MUF was associated with significant (P < 0.05) increases in hematocrit (17.6% +/- 1.6% to 21.6% +/- 2.4%), platelet count 11.1 +/- 2.5 to 12.8 +/- 2.4 x 10(4)/mm3), total plasma proteins (2.7 +/- 0.3 to 3.4 +/- 0.4 g/dl), and albumin (1.6 +/- 0.2 to 2.1 +/- 0.2 g/dl). Fibrinogen, prothrombin, and factor VII also increased significantly (P < 0.05) during MUF, but factor IX and factor X did not change. CONCLUSION: We conclude that MUF attenuates the dilutional coagulopathy that occurs during CPB in children. There were slight improvements in the coagulation factors when MUF was employed.