Related Experiment Videos
Phenotypic alterations in circulating monocytes induced by open heart surgery using heparinized and nonheparinized
O Ljunghusen1, I Cederholm, J Lundahl
1Department of Medical Microbiology and Immunology, University Hospital, Linköping, Sweden.
Insights
Heparin-coated cardiopulmonary bypass systems reduce leukocyte activation during surgery compared to noncoated systems. This finding may explain improved immune function post-coronary bypass surgery.
Area of Science:
- Cardiovascular Surgery
- Immunology
- Biomedical Engineering
Background:
- Cardiopulmonary bypass (CPB) systems are essential for cardiac surgery but can activate leukocytes and the complement system.
- Leukocyte activation during CPB is linked to systemic inflammation and potential organ dysfunction post-surgery.
- The impact of heparin-coated versus noncoated CPB circuits on leukocyte activation requires further elucidation.
Purpose of the Study:
- To compare the effects of heparin-coated and noncoated CPB systems on leukocyte activation in patients undergoing coronary bypass surgery.
- To investigate the specific markers of leukocyte and complement system activation during CPB.
- To assess the impact of CPB system type on monocyte phenotype and circulating leukocyte counts post-operatively.
Main Methods:
- Flow cytometry analysis of leukocyte activation markers (e.g., CD11b, HLA-DR, CD62L) and complement activation (C3a desArg).
- Comparison of 31 patients undergoing coronary bypass surgery utilizing either heparin-coated or noncoated CPB systems.
- Monitoring of leukocyte counts and monocyte phenotype in peripheral blood samples during and after CPB.
Main Results:
- Noncoated CPB systems showed significantly higher complement activation (C3a desArg) and granulocyte beta2 integrin (CD11b) upregulation.
- A loss of circulating monocytes was observed with noncoated systems during bypass.
- Post-operatively, both groups exhibited leukocytosis with reduced CD11b and HLA-DR expression on monocytes, suggesting altered cell phenotypes.
Conclusions:
- Heparin-coated CPB systems mitigate leukocyte and complement system activation compared to noncoated systems.
- The observed alterations in monocyte phenotype post-surgery may contribute to impaired immune function.
- Minimizing CPB-induced inflammation through material surface modification is crucial for improving patient outcomes after cardiac surgery.
Abstract:
In this study of 31 patients with coronary bypass surgery, we used flow cytometry to compare heparin-coated and noncoated cardiopulmonary bypass systems on leukocyte activation. We found significant differences between the groups during bypass, with activation of the complement system, measured as elevated levels of C3a desArg, upregulation of granulocyte beta2 integrin (CD11b), and a loss of circulating monocytes when noncoated systems were used. In both groups an early increase in the monocyte cell surface CD62L expression was obvious while the percentage of human leukocyte antigen (HLA)-DR positive monocytes did not alter. The morning after the operation, leukocytosis was present, together with a highly significant reduction in the monocyte expression of CD11b and HLA-DR, indicating the recruitment to the peripheral blood of cells with altered phenotypes. This alteration in phenotype on potent inflammatory cells may be one part of the impaired function of the immunological system reported after major surgery.