Treatment of chronic rhinosinusitis with nasal polyp (CRSwNP) primarily aims to shrink or eliminate nasal polyps. We recently reported that excessive fibrin deposition plays pivotal role in forming nasal polyp. Nattokinase (NK), a serine protease produced by Bacillus subtilis, has been reported to be a strong fibrinolytic enzyme. Therefore, we investigate the effects of NK on nasal polyp tissues in patients with CRSwNP.
METHODS: To evaluate the direct effects of NK on nasal polyp tissues, pieces of nasal polyps were incubated either with saline or NK solution (10-1000FU/ml) at 37℃ for 24 h with gentle agitation, after which the weighs changes were observed. 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. NK capsules were also administered orally to patients with CRSwNP for 12 weeks, and observed clinical findings.
NK effectively reduce the weight of nasal polyp tissue in dose and time dependent manner. Viscosity of nasal discharge and sputum from patient with CRSwNP and asthma, respectively, was significantly reduced by incubation with NK solution. We also found that oral administration of NK improves the clinical findings of patients with CRSwNP.
NK may be an effective alternative therapeutic option in patients with CRSwNP and comorbid asthma by through fibrin degradation of nasal polyp tissue or mucus.