BackgroundLaryngopharyngeal reflux (LPR), with its increasing morbidity, is attracting considerable attention. In recent years, the causal role between LPR and laryngeal carcinoma has been debated. The main harmful component of LPR is pepsin, which has been shown to induce mucosal inflammation by damaging the mucous membrane. Thus, pepsin is linked to an increased risk of laryngeal carcinoma, although the potential mechanism remains largely unknown.MethodsThe human laryngeal carcinoma cell lines Hep-2 and Tu212 were exposed to different pepsin concentrations and the morphology, proliferation, migration, secretion of inflammatory cytokines, and epithelial–mesenchymal transition (EMT) of the cells were assessed. To evaluate whether interleukin-8 (IL-8) had a causal relationship with pepsin and EMT, an IL-8 inhibitor was used to suppress IL-8 secretion during pepsin exposure and the expression of EMT markers, cell proliferation, and migration were analyzed.ResultsPepsin promoted proliferation, colony formation, migration, and IL-8 secretion of Hep-2 and Tu212 cells in vitro. Furthermore, increased pepsin concentrations changed the morphology of Hep-2 and Tu212 cells; levels of the epithelial marker E-cadherin were reduced and those of mesenchymal markers vimentin and β-catenin and the transcription factors snail and slug were elevated. A similar effect was observed in laryngeal carcinoma tissues using immunohistochemistry. IL-8 level was reduced and EMT was restored when pepsin was inhibited by pepstatin. EMT was weakened after exposure to the IL-8 inhibitor, with significant reduction in pepsin-induced cell proliferation and migration.ConclusionsPepsin may induce EMT in laryngeal carcinoma through the IL-8 signaling pathway, which indicates that it has potential role in enhancing cell proliferation and metastasis of laryngeal carcinoma.Electronic supplementary materialThe online version of this article (10.1186/s12935-019-0772-7) contains supplementary material, which is available to authorized users.

Laryngopharyngeal reflux (LPR) induces a differential damage effect on several anatomic sites within the larynx and hypopharynx; therefore, an in vitro model is needed for each anatomic site. This study aimed to establish a primary culture method for human laryngeal and hypopharyngeal epithelial cells derived from multiple anatomic sites. Surgical mucosa specimens were treated with a two-step enzymatic strategy to establish a primary culture. Of the 46 samples, primary cultivation was achieved successfully with 36 samples, and the positive ratio was 78.3%. In addition, flow cytometry revealed that these primary cells were epithelial cells with a purity of 94.9%. The proliferative ability was confirmed by positive staining for Ki-67. Laryngeal and hypopharyngeal epithelial cells from multiple sites exhibited similar epithelial morphology and positive cytokeratin expression. These cells can be cultured to passage 4. In summary, we successfully established the in vitro epithelial model of larynx and hypopharynx subsites, which may potentially be used as a platform for reflux research, especially for site-specific damage effect.

Objective The role of lifestyle habits in patients with laryngopharyngeal reflux disease (LPRD) is comparatively underexplored. We aim to examine the specific lifestyle habits in patients with LPRD. METHODS Systematic sampling was applied to select respondents aged 18 through 80 years in otorhinolaryngology-head and neck surgery (OHNS) clinics in Nan Fang Hospital during August 2017–July 2018, 1658 eligible participants were included by a systematic sampling method. Subjects with RSI score>13 were considered as LPRD patients. The risk of reflux symptoms was estimated and multivariate calculated as odds ratios in relation to exposure to tobacco smoking, alcohol, coffee, tea, carbonated drinks, chocolate, spicy food, night sleep time, dinner-to-bed time, subjective sleep quality, and physical exercise. Results There was a significant dose-response association between carbonated beverage and LPRD. Among people who had drinking carbonated drinks the odds ratio was 1.76 (OR 1.77, 95% CI 1.24–2.50, P = .002) compared with non-carbonated drinker. A similar positive association was found for poor subjective sleep quality and shorter night sleeping time, the odds ratio for reflux was 1.58 (95% CI 1.14 to 2.18) among those who always have poor subjective sleep quality compared with those whose have good subjective sleep quality. The odds ratio for reflux was 2.29 (95% CI 1.23–4.28, P = .015) among those who always sleep 3–5 hours every night compared with those who sleep more than 8 hours every night. Beyond that, we found high BMI may have a negative correlation with LPRD, the odds ratio for reflux was .61 (95% CI 0.39 to .95, P = .054) among those whose BMI >25 kg/m2 compared with those BMI ≤ 20 kg/m2. Conclusions Patients with LPRD may have certain lifestyle habits, avoid carbonated beverage, poor subjective sleep quality, and lack of sleep should be advised in treatment of LPRD.