Low degree of activation of circulating neutrophils determined by flow cytometry during cardiac surgery with cardiopulmonary bypass.
BACKGROUND
Enhanced expression of adhesion molecules LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) following cardiac surgery with cardiopulmonary bypass (CPB) is held responsible for postoperative complications. Surface expression of these molecules, intracellular pH (pH(i)), and oxidative burst capacity was analyzed to test for neutrophil activation during pediatric cardiac surgery.


METHODS
Blood samples were drawn from 36 patients (age: 3--16 years) 24 h preoperatively, after onset of anesthesia, after connection to CPB (CPB1, before and after passing CPB, n = 15), at reperfusion (CPB2), and up to 7 days postoperatively. Cells adhering to CPB filters were isolated (n = 11). Antigen expression, pH(i), and oxidative burst capacity on neutrophils was analyzed by flow cytometry.


RESULTS
During surgery, oxidative burst capacity was at low level with a mild increase only 1 day after surgery. pH(i) was decreased throughout the surgery. Surgery induced more than 36% decrease of LFA-1 and Mac-1 expression (P < 0.03). Up to postoperative day 7, no increase of antigen expression above baseline was found. Neutrophils isolated from filters of the CPB had increased LFA-1 and Mac-1 expression (all P < 0.05). Integrin expression on neutrophils passing the CPB at CPB1 was decreased (P < 0.05).


CONCLUSIONS
Reduced adhesion molecule expression on neutrophils may be due to selective filtration of highly adhesive cells. This, in combination with low-level oxidative burst capacity, induced by immunosuppressive cytokines (e.g., interleukin-10), reduced the neutrophil activity. Our data indicate that increased activity of circulating neutrophils cannot exclusively be held responsible for postoperative complications after surgery with CPB.
Pediatric Cardiology, Cardiac Center Leipzig, University of Leipzig, Germany. tarnok@medizin.uni-leipzig.de
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A
Tárnok
J
J
Bocsi
H
H
Rössler
V
V
Schlykow
P
P
Schneider
J
J
Hambsch
D000293:Adolescent; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D002648:Child; D002675:Child, Preschool; D005434:Flow Cytometry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016169:Lymphocyte Function-Associated Antigen-1 / Q000032:analysis; D016177:Macrophage-1 Antigen / Q000032:analysis; D018375:Neutrophil Activation; D009504:Neutrophils / Q000737:chemistry / Q000276:immunology*; D011183:Postoperative Complications / Q000276:immunology*; D016897:Respiratory Burst; D013997:Time Factors
D016169:Lymphocyte Function-Associated Antigen-1; D016177:Macrophage-1 Antigen