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document
Complement activation on the surface of cell-derived microparticles during cardiac surgery with cardiopulmonary bypass - is retransfusion of pericardial blood harmful ? OBJECTIVES To investigate whether cell-derived microparticles play a role in complement activation in pericardial blood of patients undergoing cardiac surgery with cardiopulmonary bypass ( CPB ) and whether microparticles in pericardial blood contribute to systemic complement activation upon retransfusion . METHODS Pericardial blood of 13 patients was retransfused in 9 and discarded in 4 cases . Microparticles were isolated from systemic blood collected before anesthesia ( T1 ) and at the end of CPB ( T2 ) , and from pericardial blood . The microparticles were analyzed by flow cytometry for bound complement components C1q , C4 and C3 , and bound complement activator molecules C-reactive protein ( CRP ) , serum amyloid P-component ( SAP ) , immunoglobulin ( Ig ) M and IgG . Fluid-phase complement activation products ( C4b/c , C3b/c ) and activator molecules were determined by ELISA . RESULTS Compared with systemic T1 blood , pericardial blood contained increased C4b/c and C3b/c , and increased levels of microparticles with bound complement components . In systemic T1 samples , microparticle-bound CRP , whereas in pericardial blood , microparticle-bound SAP and IgM were associated with complement activation . At the end of CPB , increased C3b/c ( but not C4b/c ) was present in systemic T2 blood compared with T1 , while concentrations of microparticles binding complement components and of those binding complement activator molecules were similar . Concentrations of fluid-phase complement activation products and microparticles were similar in patients whether or not retransfused with pericardial blood . CONCLUSIONS In pericardial blood of patients undergoing cardiac surgery with CPB , microparticles contribute to activation of the complement system via bound SAP and IgM . Retransfusion of pericardial blood , however , does not contribute to systemic complement activation .
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Intervention_Surgical
cardiopulmonary bypass
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Intervention_Surgical
cardiac surgery with cardiopulmonary bypass ( CPB ) and
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Intervention_Physical
blood collected before anesthesia
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Intervention_Surgical
CPB
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Intervention_Surgical
CPB
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Outcome_Physical
complement activation
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Outcome_Physical
systemic complement activation
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Outcome_Physical
C4b/c and C3b/c
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Outcome_Physical
levels of microparticles
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Outcome_Physical
C3b/c ( but not C4b/c )
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Outcome_Physical
Concentrations of fluid-phase complement activation products and microparticles
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Outcome_Physical
activation of the complement system
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Outcome_Physical
systemic complement activation
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Participant_Condition
cardiopulmonary bypass
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Participant_Condition
cardiac surgery with cardiopulmonary bypass ( CPB )
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Participant_Sample-size
13