title: Capsaicin treatment reduces nasal hyperreactivity and transient receptor potential cation channel subfamily V, receptor 1 (TRPV1) overexpression in patients with idiopathic rhinitis.
abstract: BACKGROUND
  Idiopathic rhinitis (IR) is a prevalent condition for which capsaicin nasal spray is the most effective treatment. However, the mechanisms underlying IR and the therapeutic action of capsaicin remain unknown.
  
  
  OBJECTIVE
  We sought to investigate the molecular and cellular bases of IR and the therapeutic action of capsaicin.
  
  
  METHODS
  Fourteen patients with IR and 12 healthy control subjects (HCs) were treated with intranasal capsaicin. The therapeutic effect was assessed in patients with IR by using visual analog scale and therapeutic response evaluation scores, and nasal hyperreactivity was evaluated by means of cold dry air provocation. Nasal samples served to measure the levels of neuromediators and expression of chemosensory cation channels, protein gene product 9.5 (PGP 9.5), and the mast cell marker c-kit. The effects of capsaicin were also tested in vitro on human nasal epithelial cells and mast cells.
  
  
  RESULTS
  Patients with IR had higher baseline transient receptor potential cation channel subfamily V, receptor 1 (TRPV1) expression in the nasal mucosa and higher concentrations of substance P (SP) in nasal secretions than HCs. Symptomatic relief was observed in 11 of 14 patients with IR after capsaicin treatment. Expression of TRPV1; transient receptor potential cation channel subfamily M, receptor 8 (TRPM8); and PGP 9.5 was only reduced in patients with IR after capsaicin treatment. Capsaicin did not alter c-KIT expression or nasal epithelial morphology in patients with IR and HCs nor did it induce apoptosis or necrosis in cultured human nasal epithelial cells and mast cells.
  
  
  CONCLUSIONS
  IR features an overexpression of TRPV1 in the nasal mucosa and increased SP levels in nasal secretions. Capsaicin exerts its therapeutic action by ablating the TRPV1-SP nociceptive signaling pathway in the nasal mucosa.
authors.affiliation: Clinical Division of Otorhinolaryngology, Head & Neck Surgery, University Hospitals Leuven, Leuven, Belgium; Laboratory of Clinical Immunology, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
authors.forename: Laura
authors.initials: L
authors.lastname: Van Gerven
authors.affiliation: Laboratory for Ion Channel Research, Department of Molecular Cell Biology, KU Leuven, Leuven, Belgium.
authors.forename: Yeranddy A
authors.initials: YA
authors.lastname: Alpizar
authors.affiliation: Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Leuven, Belgium.
authors.forename: Mira M
authors.initials: MM
authors.lastname: Wouters
authors.affiliation: Clinical Division of Otorhinolaryngology, Head & Neck Surgery, University Hospitals Leuven, Leuven, Belgium; Laboratory of Clinical Immunology, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
authors.forename: Valérie
authors.initials: V
authors.lastname: Hox
authors.affiliation: Laboratory of Translational Cell and Tissue Research, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium; Clinical Division of Pathology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Esther
authors.initials: E
authors.lastname: Hauben
authors.affiliation: Clinical Division of Otorhinolaryngology, Head & Neck Surgery, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Mark
authors.initials: M
authors.lastname: Jorissen
authors.affiliation: Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Leuven, Belgium.
authors.forename: Guy
authors.initials: G
authors.lastname: Boeckxstaens
authors.affiliation: Laboratory for Ion Channel Research, Department of Molecular Cell Biology, KU Leuven, Leuven, Belgium.
authors.forename: Karel
authors.initials: K
authors.lastname: Talavera
authors.affiliation: Clinical Division of Otorhinolaryngology, Head & Neck Surgery, University Hospitals Leuven, Leuven, Belgium; Laboratory of Clinical Immunology, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium. Electronic address: peter.hellings@uzleuven.be.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Hellings
mesh_terms: D000328:Adult; D002211:Capsaicin / Q000008:administration & dosage* / Q000009:adverse effects; D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D008297:Male; D008407:Mast Cells / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D009297:Nasal Mucosa / Q000378:metabolism / Q000473:pathology; D059085:Nasal Sprays; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis; D012221:Rhinitis, Allergic, Perennial / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D018689:Sensory System Agents / Q000008:administration & dosage* / Q000009:adverse effects; D050916:TRPV Cation Channels / Q000096:biosynthesis*; D043222:Ubiquitin Thiolesterase / Q000096:biosynthesis
chemical_list: D059085:Nasal Sprays; D018689:Sensory System Agents; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; C482860:UCHL1 protein, human; D019009:Proto-Oncogene Proteins c-kit; D043222:Ubiquitin Thiolesterase; D002211:Capsaicin
keywords: Capsaicin treatment; TRPV1; TRPV1-SP signaling pathway; afferent nerves; idiopathic rhinitis; nasal hyperreactivity