OBJECTIVE: We have documented an impaired neutrophil migration toward the infectious focus in severe sepsis. This phenomenon appears to be mediated by nitric oxide, the release of which is stimulated by circulating inflammatory cytokines released by immune cells after stimulation by bacteria and/or their products. Toll-like receptor 4 (TLR4) is the major recognition receptor for lipopolysaccharide, a component of Gram-negative bacterial cell walls. In the present study, we investigated whether TLR4 is involved in the failure of neutrophil migration in mice subjected to polymicrobial or Gram-negative sepsis. DESIGN: Controlled animal study. SETTING: University research laboratory. SUBJECTS: Male C3H/HeJ (TLR4-deficient) and C3H/HePas (TLR4-normal) mice. INTERVENTIONS: Mice were subjected to sublethal or lethal polymicrobial sepsis, both induced by cecal ligation and puncture or intraperitoneal polymicrobial inoculation, and subjected to sublethal Gram-negative sepsis induced by intraperitoneal Salmonella typhimurium inoculation (GNI). Survival was monitored for 5 days. In separate experiments, mice were killed 6 hrs after sepsis induction, and intraperitoneal neutrophil migration, bacteremia, lung neutrophil sequestration, and levels of cytokines, chemokines, and nitrate were evaluated. MEASUREMENTS AND RESULTS: TLR4-deficient (C3H/HeJ) mice presented incapacity to promote neutrophil recruitment to the infectious site after sublethal GNI, resulting in high mortality. However, TLR4 signaling is not essential to display neutrophil migration in sublethal polymicrobial sepsis induced by both cecal ligation and puncture and polymicrobial inoculation models, but surprisingly, it is crucial to establish the impairment of neutrophil migration in lethal polymicrobial sepsis, since TLR4-deficient mice that underwent lethal cecal ligation and puncture or polymicrobial inoculation did not present failure of neutrophil migration to infectious focus. As a consequence, these animals presented low bacteremia and a high survival rate and did not display systemic inflammation, determined by high levels of circulating cytokines and lung neutrophil sequestration and chemokine production. CONCLUSION: These results highlight the harmful role of TLR4 signaling in polymicrobial severe sepsis.
OBJECTIVE: We have documented an impaired neutrophil migration toward the infectious focus in severe sepsis. This phenomenon appears to be mediated by nitric oxide, the release of which is stimulated by circulating inflammatory cytokines released by immune cells after stimulation by bacteria and/or their products. Toll-like receptor 4 (TLR4) is the major recognition receptor for lipopolysaccharide, a component of Gram-negative bacterial cell walls. In the present study, we investigated whether TLR4 is involved in the failure of neutrophil migration in mice subjected to polymicrobial or Gram-negative sepsis. DESIGN: Controlled animal study. SETTING: University research laboratory. SUBJECTS: Male C3H/HeJ (TLR4-deficient) and C3H/HePas (TLR4-normal) mice. INTERVENTIONS:Mice were subjected to sublethal or lethal polymicrobial sepsis, both induced by cecal ligation and puncture or intraperitoneal polymicrobial inoculation, and subjected to sublethal Gram-negative sepsis induced by intraperitoneal Salmonella typhimurium inoculation (GNI). Survival was monitored for 5 days. In separate experiments, mice were killed 6 hrs after sepsis induction, and intraperitoneal neutrophil migration, bacteremia, lung neutrophil sequestration, and levels of cytokines, chemokines, and nitrate were evaluated. MEASUREMENTS AND RESULTS:TLR4-deficient (C3H/HeJ) mice presented incapacity to promote neutrophil recruitment to the infectious site after sublethal GNI, resulting in high mortality. However, TLR4 signaling is not essential to display neutrophil migration in sublethal polymicrobial sepsis induced by both cecal ligation and puncture and polymicrobial inoculation models, but surprisingly, it is crucial to establish the impairment of neutrophil migration in lethal polymicrobial sepsis, since TLR4-deficientmice that underwent lethal cecal ligation and puncture or polymicrobial inoculation did not present failure of neutrophil migration to infectious focus. As a consequence, these animals presented low bacteremia and a high survival rate and did not display systemic inflammation, determined by high levels of circulating cytokines and lung neutrophil sequestration and chemokine production. CONCLUSION: These results highlight the harmful role of TLR4 signaling in polymicrobial severe sepsis.
Authors: Jose C Alves-Filho; Fabiane Sônego; Fabricio O Souto; Andressa Freitas; Waldiceu A Verri; Maria Auxiliadora-Martins; Anibal Basile-Filho; Andrew N McKenzie; Damo Xu; Fernando Q Cunha; Foo Y Liew Journal: Nat Med Date: 2010-05-16 Impact factor: 53.440
Authors: Jose C Alves-Filho; Andressa Freitas; Fabricio O Souto; Fernando Spiller; Heitor Paula-Neto; Joao S Silva; Ricardo T Gazzinelli; Mauro M Teixeira; Sergio H Ferreira; Fernando Q Cunha Journal: Proc Natl Acad Sci U S A Date: 2009-02-20 Impact factor: 11.205
Authors: Dae Won Park; Shaoning Jiang; Jean-Marc Tadie; William S Stigler; Yong Gao; Jessy Deshane; Edward Abraham; Jaroslaw W Zmijewski Journal: Mol Med Date: 2013-11-08 Impact factor: 6.354