N. J. Klingensmith1, Z. Liang1, J. D. Lyons1, C. M. Coopersmith1 1Emory University,Surgery/Critical Care,Atlanta, GA, USA
Introduction:
Sepsis has been shown to increase intestinal permeability and increase mortality. Intestinal epithelial cells and their associated tight junction proteins are crucial for regulating intestinal permeability. Junctional Adhesion Molecule A (JAM-A) is a protein found in the intercellular tight junction that has been implicated in regulating gut barrier function. Previous studies have shown that JAM-A-/- mice have increased gut mucosal permeability at baseline. However, how intestinal permeability and overall survival are altered in JAM-A deficient mice during sepsis has yet to be determined.
Methods:
6-8 week old male and female C57Bl/6 (WT) or JAM-A-/- mice underwent cecal ligation and puncture (CLP) to induce sepsis. Following sepsis, mice were followed for seven days for survival or sacrificed at 24 hours for functional studies. Intestinal permeability was assessed by quantifying serum fluorescent dextran (FD-4, 4.4kDa) following oral gavage 5 hours prior to sacrifice. Blood and peritoneal cultures were taken via sterile cardiac puncture and peritoneal lavage, respectively, and incubated on sheep blood agar plates for 48 hours before quantification. A Log-Rank test was performed for survival studies. For two-way comparisons, a Student’s t-test or Mann-Whitney test was performed depending on Gaussian distribution and a p-value of <0.05 was considered significant.
Results:
Intestinal permeability was increased in JAM-A-/- mice compared to WT mice (mean, 1031±516.3 ng/ml vs. 699±295.1 ng/ml, p=0.04, n=13-15). However, JAM-A-/- mice displayed a decrease in systemic bacterial burden compared to controls (log transform mean, 0.9731±1.819 CFU/ml vs. 2.751±2.013 CFU/ml, p=0.007, n=18-20) suggesting sepsis induced intestinal hyperpermeability does not correlate with greater bacteremia in JAM-A deficient mice. There were no statistical differences in peritoneal cultures in JAM-A-/- mice compared to controls (log transform mean, 3.495±2.069 CFU/ml vs. 4.646±2.305 CFU/ml, p=0.11, n=18-20). Importantly, JAM-A-/- mice had improved survival compared to WT mice (95% vs. 55%, p=0.003, n=20/group).
Conclusion:
Though JAM-A-/- mice have an increase in intestinal permeability during sepsis, they display less bacteremia and overall improvement in survival compared to WT mice. These opposing findings suggest that deleting JAM-A, while increasing intestinal permeability, alters other physiologic parameters which appear to predominate allowing for the improved survival.
