title: Probiotic administration reduces mortality and improves intestinal epithelial homeostasis in experimental sepsis.
abstract: BACKGROUND
  Recent clinical trials indicate that probiotic administration in critical illness has potential to reduce nosocomial infections and improve clinical outcome. However, the mechanism(s) of probiotic-mediated protection against infection and sepsis remain elusive. The authors evaluated the effects of Lactobacillus rhamnosus GG (LGG) and Bifidobacterium longum (BL) on mortality, bacterial translocation, intestinal epithelial homeostasis, and inflammatory response in experimental model of septic peritonitis.
  
  
  METHODS
  Cecal ligation and puncture (n=14 per group) or sham laparotomy (n=8 per group) were performed on 3-week-old FVB/N weanling mice treated concomitantly with LGG, BL, or vehicle (orally gavaged). At 24 h, blood and colonic tissue were collected. In survival studies, mice were given probiotics every 24 h for 7 days (LGG, n=14; BL, n=10; or vehicle, n=13; shams, n=3 per group).
  
  
  RESULTS
  Probiotics significantly improved mortality after sepsis (92 vs. 57% mortality for LGG and 92 vs. 50% mortality for BL; P=0.003). Bacteremia was markedly reduced in septic mice treated with either probiotic compared with vehicle treatment (4.39±0.56 vs. 1.07±1.54; P=0.0001 for LGG; vs. 2.70±1.89; P=0.016 for BL; data are expressed as mean±SD). Sepsis in untreated mice increased colonic apoptosis and reduced colonic proliferation. Probiotics significantly reduced markers of colonic apoptosis and returned colonic proliferation to sham levels. Probiotics led to significant reductions in systemic and colonic inflammatory cytokine expression versus septic animals. Our data suggest that involvement of the protein kinase B pathway (via AKT) and down-regulation of Toll-like receptor 2/Toll-like receptor 4 via MyD88 in the colon may play mechanistic roles in the observed probiotic benefits.
  
  
  CONCLUSIONS
  Our data demonstrate that probiotic administration at initiation of sepsis can improve survival in pediatric experimental sepsis. The mechanism of this protection involves prevention of systemic bacteremia, perhaps via improved intestinal epithelial homeostasis, and attenuation of the local and systemic inflammatory responses.
authors.affiliation: Department of Anesthesiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Khailova
authors.forename: Daniel N
authors.initials: DN
authors.lastname: Frank
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Dominguez
authors.forename: Paul E
authors.initials: PE
authors.lastname: Wischmeyer
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D016470:Bacteremia; D001644:Bifidobacterium; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects; D003106:Colon / Q000382:microbiology; D006706:Homeostasis / Q000187:drug effects*; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000097:blood; D007413:Intestinal Mucosa / Q000382:microbiology / Q000502:physiology* / Q000503:physiopathology; D052201:Lacticaseibacillus rhamnosus; D051379:Mice; D051058:Oncogene Protein v-akt / Q000378:metabolism; D010538:Peritonitis / Q000188:drug therapy / Q000382:microbiology / Q000503:physiopathology; D019936:Probiotics / Q000627:therapeutic use*; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D018805:Sepsis / Q000382:microbiology / Q000401:mortality* / Q000503:physiopathology*; D051193:Toll-Like Receptors / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D015850:Interleukin-6; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; D012313:RNA; D051058:Oncogene Protein v-akt; D051057:Proto-Oncogene Proteins c-akt