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Changes in leucocyte counts and soluble intercellular adhesion molecule-1 and E-selectin during cardiopulmonary
H J Williams1, N Rebuck, M J Elliott
1University of Sheffield Medical School, UK.
Insights
Cardiopulmonary bypass (CPB) in children causes capillary leak and lung issues. Study shows altered soluble adhesion molecules and neutrophil counts during CPB may indicate increased leukocyte sequestration and endothelial damage.
Area of Science:
- Pediatric surgery
- Cardiovascular surgery
- Immunology
Background:
- Cardiopulmonary bypass (CPB) in children can lead to postoperative capillary leak and pulmonary dysfunction.
- Neutrophil sequestration in the lungs may contribute to endothelial damage during CPB.
- Endothelial adhesion molecules (e.g., E-selectin, ICAM-1) and their soluble forms play a role in leukocyte adhesion.
Purpose of the Study:
- To investigate changes in plasma concentrations of soluble E-selectin and soluble ICAM-1 during CPB in pediatric patients.
- To correlate these changes with leukocyte counts and assess their potential role in CPB-associated complications.
Main Methods:
- Plasma concentrations of soluble E-selectin and soluble ICAM-1 were measured using fixed-phase immunoassays.
- Leukocyte counts (total, lymphocyte, neutrophil) were monitored in 10 pediatric patients undergoing CPB.
- Measurements were taken preoperatively, during maximum hypothermia, and at 24 hours postoperatively.
Main Results:
- Soluble L-selectin and ICAM-1 levels decreased during CPB, largely due to hemodilution.
- White blood cell counts significantly decreased during CPB, suggesting leukocyte sequestration.
- Neutrophil counts increased significantly in the postoperative period, while lymphocyte counts returned to baseline.
Conclusions:
- Changes in circulating leukocyte numbers during CPB may reflect altered endothelial adhesion and sequestration.
- Soluble adhesion molecule levels and leukocyte count dynamics provide insights into CPB-induced inflammatory responses.
- Further research is needed to fully elucidate the role of soluble adhesion proteins in CPB-related complications.
Abstract:
A consequence of cardiopulmonary bypass (CPB) in young children is postoperative capillary leak and associated pulmonary dysfunction. Neutrophils sequester in the lungs and may contribute to functional endothelial damage. The endothelial adhesion molecules, E-selectin and intercellular adhesion molecule-1 (ICAM-1), mediate sequential steps in adhesion by binding to leucocyte ligands. Circulating forms of these proteins have been identified. We studied changes in the plasma concentrations of soluble E-selectin and soluble ICAM-1 using fixed phase immunoassays, and associated leucocyte counts in 10 paediatric patients undergoing CPB. Concentrations of soluble L-selectin and soluble ICAM-1 consistently fell during CPB from preoperative levels of 89 +/- 17 ng/ml (mean +/- 2SEM) and 218 + 61 ng/ml, respectively, to 39 +/- 7 ng/ml and 84 +/- 24 ng/ml, respectively at the beginning of maximum hypothermia. The haemodilution that occurred during CPB largely explained this fall, but not the more marked decrease in white cell counts that also occurred over this period (6.7 +/- 1.1 to 1.7 +/- 0.5 x 10(9)/l) which may reflect increased leucocyte sequestration. By 24 h postoperatively, levels of both soluble adhesion molecules approached preoperative concentrations, as did lymphocyte counts. In marked contrast, neutrophil counts rose appreciably towards the end of CPB, and continued to rise to a maximum of 10.9 +/- 3.1 x 10(9)/l during the immediate postoperative period and remained at these elevated levels 24 h later. Major consistent changes in circulating leucocyte numbers which occur early in cardiopulmonary bypass may reflect changes in adhesion to the endothelium and consequent sequestration. Alterations in the levels of soluble adhesion proteins may influence these processes.