title: Nattokinase, profibrinolytic enzyme, effectively shrinks the nasal polyp tissue and decreases viscosity of mucus.
abstract: BACKGROUND
  Chronic rhinosinusitis with nasal polyps (CRSwNP) is often comorbid with asthma and resistant to therapeutic interventions. We recently reported that excessive fibrin deposition caused by impairment of fibrinolysis might play pivotal role in forming nasal polyp. Nattokinase (NK), a serine protease produced by Bacillus subtilis, has been reported to be a strong fibrinolytic enzyme. NK could be a promising drug candidate for use in the treatment of both CRSwNP and asthma. The objective of this study was to investigate the effects of NK on nasal polyp tissues from patients with CRSwNP. The nasal discharge from patients with CRSwNP and sputum from subjects with asthma were also used to investigate whether NK influences the viscosity of mucus.
  
  
  METHODS
  To examine the effects on NK on nasal polyp tissues, pieces of nasal polyps were incubated either with saline or NK (10-1000 FU/ml) at 37 °C for 24 h. We assessed the presence of fibrin in nasal polyp tissue incubated with NK by means of immunohistochemistry. To examine the effects of NK on nasal discharge and sputum from patients with CRSwNP and asthma, respectively, were incubated with NK solution at 37 °C for 1 h.
  
  
  RESULTS
  NK effectively shrinks the nasal polyp tissue through fibrin degradation. We also found that the viscosity of the nasal discharge and sputum from patients with CRSwNP and asthma, respectively, was significantly reduced by incubation with NK solution.
  
  
  CONCLUSIONS
  NK may be an effective alternative therapeutic option in patients with CRSwNP and comorbid asthma by causing fibrin degradation.
authors.affiliation: Division of Otorhinolaryngology Head and Neck Surgery, Department of Sensory and Locomotor Medicine, University of Fukui, Fukui, Japan. Electronic address: tetsuji@u-fukui.ac.jp.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Takabayashi
authors.affiliation: Division of Otorhinolaryngology Head and Neck Surgery, Department of Sensory and Locomotor Medicine, University of Fukui, Fukui, Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Imoto
authors.affiliation: Division of Otorhinolaryngology Head and Neck Surgery, Department of Sensory and Locomotor Medicine, University of Fukui, Fukui, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Sakashita
authors.affiliation: Division of Otorhinolaryngology Head and Neck Surgery, Department of Sensory and Locomotor Medicine, University of Fukui, Fukui, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Division of Otorhinolaryngology Head and Neck Surgery, Department of Sensory and Locomotor Medicine, University of Fukui, Fukui, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tokunaga
authors.affiliation: Division of Otorhinolaryngology Head and Neck Surgery, Department of Sensory and Locomotor Medicine, University of Fukui, Fukui, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Division of Otorhinolaryngology Head and Neck Surgery, Department of Sensory and Locomotor Medicine, University of Fukui, Fukui, Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Narita
authors.affiliation: Third Department of Internal Medicine, University of Fukui, Fukui, Japan.
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Ishizuka
authors.affiliation: Division of Otorhinolaryngology Head and Neck Surgery, Department of Sensory and Locomotor Medicine, University of Fukui, Fukui, Japan.
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Fujieda
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001249:Asthma / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D002908:Chronic Disease; D004195:Disease Models, Animal; D004804:Eosinophils / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D005260:Female; D005337:Fibrin / Q000378:metabolism; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007958:Leukocyte Count; D008297:Male; D051379:Mice; D008875:Middle Aged; D009093:Mucus / Q000378:metabolism*; D009297:Nasal Mucosa / Q000378:metabolism / Q000473:pathology; D009298:Nasal Polyps / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D059748:Proteolysis; D012220:Rhinitis / Q000378:metabolism / Q000473:pathology; D012852:Sinusitis / Q000378:metabolism / Q000473:pathology; D013381:Subtilisins / Q000378:metabolism*; D014783:Viscosity
chemical_list: D007073:Immunoglobulin E; D005337:Fibrin; D013381:Subtilisins; C053771:nattokinase
keywords: Asthma; Chronic rhinosinusitis; Fibrin; Nasal polyps; Nattokinase