title: The influence of Lactobacillus brevis on ornithine decarboxylase activity and polyamine profiles in Helicobacter pylori-infected gastric mucosa.
abstract: BACKGROUND
  Functional probiotics may prevent Helicobacter pylori infection, and some evidence suggests that they also possess antitumor properties. Lactobacillus brevis (CD2) is a functional Lactobacillus strain with peculiar biochemical features, essentially related to the activity of arginine deiminase. This enzyme catalyzes the catabolism of arginine and affects the biosynthesis of polyamines (putrescine, spermidine, and spermine). Polyamines are polycations found in high concentrations in both normal and neoplastic cells. Our aims were: 1, to assess whether oral administration of L. brevis (CD2) affects H. pylori survival in the human gastric mucosa; 2, to evaluate the effects of L. brevis (CD2) on polyamine biosynthesis in gastric biopsies from H. pylori-positive patients.
  
  
  METHODS
  For 3 weeks before endoscopy, 22 H. pylori-positive dyspeptic patients randomly received (ratio 1 : 1) high oral doses of L. brevis (CD2) or placebo. Before and after treatment, H. pylori infection was determined by urea breath test (UBT). In gastric biopsies, ornithine decarboxylase activity and polyamine levels were, respectively, evaluated by a radiometric technique and high-pressure liquid chromatography (HPLC).
  
  
  RESULTS
  L. brevis (CD2) treatment did not eradicate H. pylori. However, a reduction in the UBT delta values occurred, suggesting a decrease in intragastric bacterial load. Significantly, L. brevis (CD2) induced a decrease in gastric ornithine decarboxylase activity and polyamine levels.
  
  
  CONCLUSIONS
  Our data support the hypothesis that L. brevis (CD2) treatment decreases H. pylori colonization, thus reducing polyamine biosynthesis. Alternatively, the arginine deiminase activity following L. brevis (CD2) administration might cause arginine deficiency, preventing polyamine generation from gastric cells.
authors.affiliation: Laboratory of Biochemistry, Scientific Institute for Digestive Diseases IRCCS 'Saverio de Bellis', Bari, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Linsalata
authors.forename: Francesco
authors.initials: F
authors.lastname: Russo
authors.forename: Pasquale
authors.initials: P
authors.lastname: Berloco
authors.forename: Maria Lucia
authors.initials: ML
authors.lastname: Caruso
authors.forename: Giovanni D I
authors.initials: GD
authors.lastname: Matteo
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Cifone
authors.forename: Claudio D E
authors.initials: CD
authors.lastname: Simone
authors.forename: Enzo
authors.initials: E
authors.lastname: Ierardi
authors.forename: Alfredo
authors.initials: A
authors.lastname: Di Leo
mesh_terms: D000328:Adult; D000368:Aged; D015317:Biogenic Polyamines / Q000378:metabolism*; D001706:Biopsy; D001944:Breath Tests; D004311:Double-Blind Method; D005260:Female; D005753:Gastric Mucosa / Q000201:enzymology / Q000378:metabolism / Q000382:microbiology*; D005773:Gastroscopy; D016481:Helicobacter Infections / Q000378:metabolism* / Q000382:microbiology; D016480:Helicobacter pylori / Q000502:physiology*; D006801:Humans; D007778:Lactobacillus / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D019936:Probiotics; D014508:Urea / Q000032:analysis
chemical_list: D015317:Biogenic Polyamines; D014508:Urea; D009955:Ornithine Decarboxylase