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Updated: Aug 17, 2026
Functional Assessment of Intestinal Permeability and Neutrophil Transepithelial Migration in Mice using a Standardized Intestinal Loop Model
Published on: February 11, 2021
Intestinal epithelial cells modulate PMN activation and apoptosis following bacterial and hypoxic challenges
Lawrence N Diebel1, David M Liberati, Jason S Taub
1Department of Surgery, Wayne State University Health Center, Detroit, MI 48201, USA. ldiebel@med.wayne.edu
Background:
The post-ischemic gut may serve to prime and activate neutrophils which may lead to the subsequent development of the systemic inflammatory response syndrome (SIRS) and multiple organ failure. However, the initiating event which may trigger this immunoinflammatory cascade from the gut is unknown. Recent studies have indicated that intestinal epithelial cells (IEC) play an integral role in generating and transmitting signals between luminal bacteria and the host cells in the underlying gut tissues. The purpose of this study was to investigate the ability of IEC to modulate PMN responses to bacteria and/or hypoxia/reoxygenation (H/R) challenges in vitro.
Methods:
Caco2 cell monolayers were established in a two-chamber cell culture system. Neutrophils from normal human volunteers were placed in the basal chamber and the cell co-culture exposed to either apical bacteria (E. coli) and/or H/R challenge. PMN apoptosis, and percentage of CD11b expression, superoxide anion production, and elastase release were subsequently quantitated.
Results:
Coculture of PMNs with Caco2 cells led to a significant reduction in neutrophil apoptosis in both normoxic and H/R conditions. CD11b expression was increased in PMNs exposed to bacteria but the greatest expression was noted with PMN cocultured with Caco2 cells and H/R. Superoxide anion production was increased in all groups following either H/R or bacterial challenge and H/R. Elastase release was highest in neutrophils following H/R and exposure to E. coli.
Conclusion:
IEC modulate PMN response to bacteria and H/R insults. This results in the production of activated neutrophils with an exaggerated lifespan which may promote remote organ failure. Attempts to modulate this response may be useful in preventing multiple organ failure following severe traumatic shock.
Insights
Intestinal epithelial cells (IECs) modulate neutrophil responses to bacterial and hypoxia/reoxygenation (H/R) challenges. This leads to activated neutrophils that may promote organ failure, suggesting therapeutic targets for shock.
Area of Science:
- Immunology
- Gastroenterology
- Critical Care Medicine
Background:
- The gut's role in post-ischemic systemic inflammatory response syndrome (SIRS) and organ failure is linked to neutrophil activation.
- The initiating trigger for this gut-derived inflammatory cascade remains unclear.
- Intestinal epithelial cells (IECs) are key in signaling between gut bacteria and host tissues.
Purpose of the Study:
- To investigate the capacity of IECs to modify polymorphonuclear leukocyte (PMN) responses.
- To assess PMN reactions to bacterial and/or hypoxia/reoxygenation (H/R) challenges in vitro.
Main Methods:
- Caco2 cell monolayers were cultured in a two-chamber system.
- Human neutrophils were placed in the basal chamber, co-cultured with Caco2 cells.
- Co-cultures were exposed to apical bacteria (E. coli) and/or H/R; PMN apoptosis, CD11b expression, superoxide anion production, and elastase release were measured.
Main Results:
- Co-culture significantly reduced neutrophil apoptosis under normoxic and H/R conditions.
- CD11b expression was highest in neutrophils co-cultured with Caco2 cells during H/R challenge with bacteria.
- Superoxide anion production and elastase release increased following H/R and/or bacterial exposure.
Conclusions:
- IECs modulate PMN responses to bacterial and H/R insults, enhancing neutrophil activation and lifespan.
- This IEC-mediated PMN activation may contribute to remote organ failure.
- Targeting this IEC-PMN interaction could help prevent multiple organ failure after severe traumatic shock.
