Related Experiment Videos
Pediatric cardiac surgery with cardiopulmonary bypass: pathways contributing to transient systemic immune suppression
1Pediatric Cardiology, Cardiac Center Leipzig, University of Leipzig, Germany.
Insights
Cardiopulmonary bypass (CPB) in pediatric cardiovascular surgery triggers an immune response, causing anti-inflammatory and pro-inflammatory shifts. Understanding these immune changes is key to managing complications like postpericardiotomy syndrome (PPS).
Area of Science:
- Immunology
- Pediatric Cardiovascular Surgery
- Critical Care Medicine
Background:
- Cardiopulmonary bypass (CPB) in pediatric cardiovascular surgery is associated with significant postoperative complications, including postpericardiotomy syndrome (PPS), capillary leak syndrome, and multiple organ failure.
- In children, PPS can lead to substantial morbidity (up to 30%) and mortality (up to 4%), with CPB implicated as a primary cause, though its immunologic etiology is not fully understood.
- Knowledge of the immune response to CPB is crucial for developing effective treatment strategies for these complications.
Purpose of the Study:
- To elucidate the complex immune response cascade following CPB in pediatric cardiovascular surgery.
- To investigate the interplay between pro-inflammatory and anti-inflammatory events during and after CPB.
- To establish a generalized model of immune sequelae to CPB in children to inform potential therapeutic interventions.
Main Methods:
- Analysis of immune mediators, including interleukin-6 (IL-6), IL-8, and IL-10, to assess inflammatory and anti-inflammatory responses.
- Evaluation of complement pathway activation, specifically the alternative pathway, as a CPB-specific marker.
- Assessment of leukocyte subset population shifts, activation states, and functional changes, including neutrophil inactivation and T-helper cell phenotype shifts (Th2 prevalence).
Main Results:
- CPB surgery induces a transient systemic anti-inflammatory response characterized by early IL-10 release, preceding pro-inflammatory cytokine release (IL-6, IL-8).
- CPB is associated with specific activation of the alternative complement pathway and significant alterations in leukocyte populations, including neutrophil inactivation and a shift towards a Th2 phenotype in T-helper cells.
- These immune alterations, including increased immunosuppression, begin immediately after CPB initiation and may contribute to PPS development, potentially linked to atopic predisposition.
Conclusions:
- CPB in pediatric cardiovascular surgery elicits a complex, biphasic immune response involving initial systemic anti-inflammatory effects followed by a pro-inflammatory reaction to surgical trauma.
- The observed immune suppression and Th2 shift may play a role in the pathogenesis of PPS and suggest a link to allergic predispositions.
- Modulating the anti-inflammatory response presents a potential therapeutic avenue for managing CPB-associated complications, warranting further investigation.
Abstract:
Cardiovascular surgery with cardiopulmonary bypass (CPB) can lead to postoperative complications like postpericardiotomy syndrome (PPS), capillary leak syndrome, or multiple organ failure. In children, PPS morbidity is up to 30%, and intra- and immediate postoperative mortality is up to 4%. For these complications, the CPB is made responsible. Its etiology is not yet clarified in detail, but is thought to be of immunologic origin. The exact knowledge of these reactions is crucial for the selection of treatment strategies. The immune response to CPB surgery in children comprises of a cascade of pro- and anti-inflammatory events. Proinflammatory responses are indicated by the release of interleukin (IL)-6 and IL-8, and the activation of alternative complement pathway. This reaction is mainly a response to surgical trauma and medication and only activation of the alternative complement pathway is CPB specific. Antiinflammatory response during CPB surgery is serologically indicated by the systemic release of the immunosuppressive cytokine IL-10 already before that of proinflammatory cytokines. CPB surgery induces population shifts of the leukocyte subsets, changes their degree of activation, and contributes to the phenotype of a peripheral immune suppression. Circulating neutrophils are selectively filtered and inactivated. T-helper (Th) cells shift transiently to the Th2 phenotype, indicating the prevalence for a humoral immune response. These alterations start immediately after the onset of the CPB. Increased immunosuppression may be involved in PPS development and may be linked to an allergic/atopic predisposition. A generalized model of the immune sequela to pediatric cardiovascular surgery with CPB is drawn. CPB induces a systemic transient anti-inflammatory response by elimination of activated cells, by compensatory reaction to local, systemically not observable, proinflammatory responses, by IL-10 release, by anesthetics and medication, and by leukocyte extravasation. The subsequent proinflammatory reaction is the reaction to surgical trauma modulating the anti-inflammatory reaction. Possible therapeutic consequences of these findings may include treatment strategies that modulate the anti-inflammatory response. More studies are needed to test this hypothesis.