title: Activation of the transforming growth factor beta pathway in bacterial otitis media.
abstract: OBJECTIVE
  Granulation tissue is common in otitis media (OM), yet little is known about the signaling pathways in the formation of granulation tissue in response to infections. In this study, we sought to investigate the activation of the transforming growth factor beta (TGF-beta) signaling pathway in the formation of granulation tissue in response to middle ear pathogens.
  
  
  METHODS
  Rat OM models were made by inoculating pneumococcus type 6A or nontypeable Haemophilus influenzae into the middle ear cavity or by obstructing the eustachian tube. Various pathway activities in the middle ear mucosa were analyzed with microarrays.
  
  
  RESULTS
  The TGF-beta signaling pathway was highly regulated in the middle ear cleft with bacterial OM, but not in the ears with eustachian tube obstruction. In ears with bacterial OM, the TGF-beta signaling pathway products were higher in Haemophilus-infected ears than in pneumococcus-infected ears.
  
  
  CONCLUSIONS
  Bacterial OM triggers granulation tissue to thrive in the middle ear cleft of rats. Nontypeable H influenzae is more potent than pneumococcus type 6A in the formation of granulation tissue. Eustachian tube obstruction alone did not contribute to granulation tissue formation in the middle ear.
authors.affiliation: Department of Otolaryngology, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Yun-Woo
authors.initials: YW
authors.lastname: Lee
authors.forename: Yunju
authors.initials: Y
authors.lastname: Chung
authors.forename: Steven K
authors.initials: SK
authors.lastname: Juhn
authors.forename: Youngki
authors.initials: Y
authors.lastname: Kim
authors.forename: Jizhen
authors.initials: J
authors.lastname: Lin
mesh_terms: D000818:Animals; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D004432:Ear, Middle / Q000166:cytology / Q000378:metabolism* / Q000382:microbiology; D004847:Epithelial Cells / Q000378:metabolism; D005064:Eustachian Tube / Q000473:pathology; D005347:Fibroblasts / Q000378:metabolism; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D006097:Granulation Tissue / Q000473:pathology; D006192:Haemophilus Infections; D046228:Microarray Analysis; D023421:Models, Animal; D010033:Otitis Media / Q000382:microbiology*; D011008:Pneumococcal Infections; D012313:RNA / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D051896:Smad Proteins, Receptor-Regulated / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D005353:Fibronectins; D018125:Receptors, Transforming Growth Factor beta; D051896:Smad Proteins, Receptor-Regulated; D016212:Transforming Growth Factor beta; D012313:RNA; D003094:Collagen