title: The expression of iron-repressible outer membrane proteins in Helicobacter pylori and its association with iron deficiency anemia.
abstract: BACKGROUND
  Helicobacter pylori infection is known to be a cause of iron deficiency anemia (IDA) that is unresponsive to iron supplements. H. pylori bind iron to a specific receptor by iron-repressible outer membrane proteins (IROMPs) under conditions of restricted iron.
  
  
  METHODS
  We compared the expression of IROMPs from strains of H. pylori under both iron-restricted and iron-supplemented conditions to determine the difference between strains with and without IDA. One standard strain, two clinical strains, and three IDA strains were cultured; and then the IROMPs were extracted under iron-restricted and iron-supplemented conditions. We used SDS-PAGE to compare the expression of the IROMPs from each strain.
  
  
  RESULTS
  IROMPs were found in IDA strains under iron-restricted conditions and their molecular sizes were estimated to be 56, 48, 41, and 37 kDa. In the iron-repleted media, the IROMPs were no longer present.
  
  
  CONCLUSIONS
  In the iron-depleted state, specific H. pylori strains associated with IDA demonstrated an advantage in iron acquisition due to a higher expression of IROMPs. Our results can explain in part why some patients with H. pylori infection are more prone to develop clinical IDA under restricted iron conditions in the host.
authors.affiliation: Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Jee Hyun
authors.initials: JH
authors.lastname: Lee
authors.forename: Yon Ho
authors.initials: YH
authors.lastname: Choe
authors.forename: Young Ok
authors.initials: YO
authors.lastname: Choi
mesh_terms: D018798:Anemia, Iron-Deficiency / Q000382:microbiology*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D016481:Helicobacter Infections / Q000150:complications* / Q000382:microbiology; D016480:Helicobacter pylori / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007501:Iron / Q000378:metabolism*; D033862:Iron-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight
chemical_list: D001425:Bacterial Outer Membrane Proteins; D033862:Iron-Binding Proteins; D007501:Iron