Importance: Surgery remains the gold standard in cholesteatoma treatment. However, the rate of recurrence is significant and the development of new nonsurgical treatment alternatives is warranted. One of the possible molecular pathways to target is the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. Objective: To investigate the JAK/STAT pathway in the middle ear mucosa in patients with acquired cholesteatoma compared with middle ear mucosa from healthy controls. Design: Case-control study. Setting: Linköping University Hospital, Sweden, and Karolinska Institutet, Stockholm, Sweden. Sampling period: February 2011 to December 2016. Participants: Middle ear mucosa from 26 patients with acquired cholesteatoma undergoing tympanoplasty and mastoidectomy, and 27 healthy controls undergoing translabyrinthine surgery for vestibular schwannoma or cochlear implantation was investigated. Main Outcomes/Measures: The expression of Interleukin-7 receptor alpha, JAK1, JAK2, JAK3, STAT5A, STAT5B, and suppressor of cytokine signaling-1 (SOCS1) were quantified using quantitative polymerase chain reaction. In addition, expression level of cyclin D2, transforming growth factor beta 1, thymic stromal lymphopoietin, CD3, and CD19 was evaluated. Results: In cholesteatoma-adjacent mucosa, SOCS1 was significantly upregulated (p= 0.0003) compared with healthy controls, whereas STAT5B was significantly downregulated (p = 0.0006). The expression of JAK1, JAK2, JAK3, and STAT5A did not differ significantly between groups. Conclusions and Relevance: To the best of our knowledge, this is the first article reporting dysregulation of the JAK/STAT pathway in cholesteatoma-adjacent mucosa. The main finding is that important players of the aforementioned pathway are significantly altered, namely SOCS1 is upregulated and STAT5B is downregulated compared with healthy controls.

Objective:To find out if nitric oxide (NO) can be locally produced in the middle ear and if chronic otitis media (COM) and acquired cholesteatoma affect the production.Design:Case-control study.Setting:Two tertiary-referral hospitals.Patients:Gaseous NO from 11 patients with unilateral perforations or grommet openings was measured with chemiluminescence. Middle ear mucosa from 48 patients with COM and 26 patients with cholesteatoma was investigated.Main Outcome Measures:Detection of NO. Expression of nitric oxide synthase (NOS) mRNA, in mucosa from COM, cholesteatoma and healthy controls, quantified using polymerase chain reaction.Results:The gaseous NO from ears with a unilateral tympanic membrane perforation or a grommet was higher (9 ± 3 ppb, n = 11) than among the controls (4 ± 1 ppb, n = 11, p = 0.04). Lower levels of eNOS (2.64 ± 0.86 mol/100,000 mol ACTB) were detected in the pooled samples from the COM group (n = 48), compared with the control group (140.48 ± 92 mol/100,000 mol ACTB, n = 45, p = 0.010). In the cholesteatoma group (n = 26), a lower expression of nNOS (5.78 × 10−6 ± 1.13 × 10−6 ΔCt) was found in comparison with the controls (1.23 × 10−4 ± 3.18 × 10−5 ΔCt, n = 15, p = 0.011).Conclusions:NO is likely a natural and permanent part of the gas mixture in the human middle ear. The presence of NOS enzymes in the middle ear mucosa indicates an ongoing NO production and the reduction of NOS in ears with cholesteatoma, and pooled samples from ears with COM, suggest a role for locally produced NO in middle ear disease.