Coronary artery bypass graft surgery dampens neutrophil responsiveness
Yoke Lin Fung,1 Chris C Silliman,2 Peter Wood,3 Robyn M Minchinton,1 John F Fraser3
1 Australian Red Cross Blood Service, Brisbane, QLD
2 Bonfils Blood Centre and University of Colorado, Denver, USA
3 Prince Charles Hospital, Brisbane, QLD
Introduction
The scientific study of neutrophils (PMNs), which have a pivotal role in coronary artery bypass graft (CABG)-associated inflammation, has been relatively limited. Previous studies have focused on the perioperative and 24-h postsurgery period,and mainly on L -selectin (CD62L) and integrins CD11b and CD18. Our serial study of five functionally important surface molecules revealed that changes caused by CABG may endure for up to 5 days and have clinical implications.
Subjects and setting
Thirty patients scheduled for elective CABG surgery at Prince Charles Hospital were recruited to the study over a 1-year period beginning January 2006. The group comprised nine women (51–82 years) and 21 men (35–79 years).
Methods
Morning blood samples were collected from patients before surgery and on Days 1, 3 and 5 after surgery. PMNs were isolated within 4 hours of blood collection and analysed:
- to determine NADPH oxidase activity; and
- to quantify surface expression of CD16 (Fc ã RIII), CD43, CD62L, CD18 and CD11b (Mac-1 or CR3) on the PMN surface.
Results
CABG induced phenotypic and functional changes to circulating PMNs of variable duration. Short-term changes included a decrease in expression of CD16 (a receptor for IgG) and CD18.
Longer-term changes included:
- a significant rise in CD43, a long, negatively charged, innately anti-adhesive molecule;
- reduced NADPH oxidase activity that persisted past Day 5.
Conclusions
The raised CD43, down-regulated CD11b response and reduced NADPH oxidase activity suggest depressed PMN function. This is important in the critical care setting as it implies that the PMN response in inflammation and infection may be depressed after CABG for longer than previously thought.
