Related Experiment Videos
Changes in neutrophil CD11b/CD18 and L-selectin expression and release of interleukin 8 and elastase in paediatric
1University of Sheffield, Dept. of Paediatrics, Sheffield Children's Hospital, UK.
Insights
Children undergoing cardiopulmonary bypass (CPB) surgery experience capillary leak due to neutrophil (PMN) interactions. This study examined PMN adhesion molecule expression and inflammatory markers during CPB, revealing altered PMN-endothelial pathways.
Area of Science:
- Immunology
- Pediatric Cardiology
- Surgical Research
Background:
- Children with congenital heart defects often require cardiopulmonary bypass (CPB).
- CPB surgery can lead to post-operative capillary leak syndrome, potentially caused by neutrophil-endothelial interactions.
- Understanding these interactions is crucial for mitigating complications.
Purpose of the Study:
- To investigate changes in neutrophil (PMN) adhesion molecule expression (CD11a/CD18, CD11b/CD18, L-selectin) during CPB.
- To assess the correlation between PMN behavior, inflammatory markers (IL-8, elastase), and capillary leak in pediatric CPB patients.
- To elucidate the role of PMN-endothelial interactions in CPB-induced injury.
Main Methods:
- Direct immunofluorescence and flow cytometry were used to analyze PMN adhesion molecule expression.
- Circulating PMN counts and inflammatory markers (IL-8, elastase, IL-1, TNF) were measured in blood samples from CPB circuits and pediatric patients.
- In vitro and in vivo experiments were conducted to simulate and observe CPB conditions.
Main Results:
- In vitro, CD11b/CD18 expression increased while L-selectin expression decreased on PMN over time.
- In vivo, changes in CD11b/CD18 and L-selectin expression were inconsistent, with fluctuating PMN counts.
- Elevated circulating IL-8 and elastase levels correlated with increased PMN counts during rewarming and reperfusion.
Conclusions:
- CPB surgery induces significant alterations in PMN adhesion molecule expression and function.
- Neutrophil activation and interaction with the endothelium are implicated in CPB-associated capillary leak.
- Further research into PMN-endothelial pathways may lead to improved management of post-CPB complications.
Abstract:
Children undergoing cardiopulmonary bypass (CPB) surgery for congenital heart defects develop an acute post-operative capillary leak which may be due to endothelial injury inflicted by adherent neutrophils (PMN). Direct immunofluorescence and flow cytometry were used to measure CD11a/CD18, CD11b/CD18 and L-selectin (L-s) expression on circulating PMN in CPB circuits containing human blood and in children undergoing CPB. In vitro, a general rise in CD11b/CD18 expression over 2 h contrasted with complete loss of L-s in a small but progressively increasing proportion of PMN. Marked but inconsistent changes in CD11b/CD18 and L-s were observed in vivo, in conjunction with fluctuations in circulating PMN count. Circulating IL-8 was detected starting at rewarming from hypothermia and reperfusion of the heart and lungs with a simultaneous, closely correlated rise in both PMN count and circulating elastase. IL-1 and TNF were not detected. These studies demonstrate changes in the pathways of PMN-endothelial interaction during and after CPB.