title: Cheilitis glandularis: immunohistochemical expression of protein water channels (aquaporins) in minor labial salivary glands.
abstract: BACKGROUND
  Cheilitis glandularis (CG) is a rare condition in which thick saliva is secreted from dilated ostia of swollen minor salivary glands from the lips. Aquaporins (AQPs) are membrane proteins that exhibit channel activity specific for water and small solutes. AQPs are essential for corporal homeostasis, and are widely expressed through human tissues. Most AQPs studies are based on renal and nervous pathophysiology; few involve salivary glands. Some previous investigators hypothesized that minor salivary gland structure and function is normal on CG.
  
  
  OBJECTIVE
  To study possible salivary synthesis alterations in CG, we compared the expression of AQPs present in minor salivary glands in specimens with CG and controls by using immunohistochemistry.
  
  
  METHODS
  Seven cases of CG and three normal controls were studied.
  
  
  RESULTS
  Intensity and patterns of expression of AQP 1, 2 and 8 differed in CG compared with controls. AQP 4 and 5 (the most important AQP in salivary function) showed identical patterns in CG and controls.
  
  
  CONCLUSIONS
  Our findings suggest that the expression and arguably, function of some of the AQPs may be altered in CG; consequently, water flow mechanism abnormalities with possible alteration in salivary composition seem to occur. External factors (mainly UV rays) seem to play an important role in CG; nonetheless, our findings suggest that there might be some degree of alteration on water transportation.
authors.affiliation: Department of Dermatology, Medical School, University of São PauloDepartment of Pathology, Dental School- University of São Paulo, São Paulo, Brazil.
authors.forename: M M S
authors.initials: MM
authors.lastname: Nico
authors.forename: J N
authors.initials: JN
authors.lastname: Melo
authors.forename: S V
authors.initials: SV
authors.lastname: Lourenço
mesh_terms: D020346:Aquaporins / Q000378:metabolism*; D016022:Case-Control Studies; D002613:Cheilitis / Q000378:metabolism*; D006801:Humans; D008046:Lip / Q000378:metabolism*; D012469:Salivary Glands / Q000378:metabolism*; D012793:Sialadenitis / Q000378:metabolism*
chemical_list: D020346:Aquaporins