Monocyte activation markers during cardiopulmonary bypass

Area of Science:

• Immunology
• Cardiovascular Surgery
• Inflammation Research

Background:

• Extracorporeal support during cardiac surgery causes Post Pump Syndrome (PPS), an inflammatory response damaging cardiac, pulmonary, and renal tissues.
• While neutrophil and lymphocyte changes are known, the role of monocytes and their activation markers during this process is less understood.

Purpose of the Study:

• To investigate monocyte activation markers, specifically HLA-DR and CD62L, in patients undergoing cardiac surgery.
• To assess changes in these markers in aortic root and coronary sinus blood samples at different time points relative to cardiopulmonary bypass.

Main Methods:

• Blood samples were collected from 19 patients undergoing cardiac surgery from the aortic root and coronary sinus.
• Samples were taken before cardiopulmonary bypass (CPB), 1 minute after aortic crossclamp release, and 10 minutes after weaning from CPB.
• Leukocyte count, monocyte count, and activation markers (HLA-DR, CD15, CD11b, CD62L) were measured.

Main Results:

• Coronary sinus HLA-DR percentage of monocyte count significantly decreased from baseline through post-CPB periods (78%, 66%, 43%).
• A similar decrease in HLA-DR was observed in aortic root samples.
• Coronary sinus CD62L showed a marked increase (55%, 68%, 73%), with a slightly lower increase in aortic root samples (51%, 68%, 63%).

Conclusions:

• The observed decrease in HLA-DR suggests reduced monocyte immunological competence following cardiac surgery.
• Increased CD62L may sensitize monocytes to endothelial interactions, potentially contributing to the atherosclerotic process.