The integrity and barrier function of porcine vocal fold epithelium: its susceptibility to damage by deoxycholic acid compared with pepsin

In vitro model to evaluate effect of acidic pepsin on vocal fold barrier function

The pathophysiology of laryngopharyngeal reflux (LPR) and its impact on the vocal fold is not well understood, but may involve acid damage to vocal fold barrier functions. Two different components encompass vocal fold barrier function: the mucus barrier and tight junctions. Mucus retained on epithelial microprojections protects the inside of the vocal fold by neutralizing acidic damage. Tight junctions control permeability between cells. Here we developed an in vitro experimental system to evaluate acidic injury and repair of vocal fold barrier functions. We first established an in vitro model of rat vocal fold epithelium that could survive at least one week after barrier function maturation. The model enabled repeated evaluation of the course of vocal fold repair processes. Then, an injury experiment was conducted in which vocal fold cells were exposed to a 5-min treatment with acidic pepsin that injured tight junctions and cell surface microprojections. Both of them healed within one day of injury. Comparing vocal fold cells treated with acid alone with cells treated with acidic pepsin showed that acidic pepsin had a stronger effect on intercellular permeability than acid alone, whereas pepsin had little effect on microprojections. This result suggests that the proteolytic action of pepsin has a larger effect on protein-based tight junctions than on phospholipids in microprojections. This experimental system could contribute to a better understanding of vocal fold repair processes after chemical or physical injuries, as well as voice problems due to LPR pathogenesis.

Airway Impedance: A Novel Diagnostic Tool to Predict Extraesophageal Airway Inflammation

OBJECTIVE

To validate a novel biomarker, airway impedance for extraesophageal disease.

STUDY DESIGN

We prospectively recruited patients with respiratory symptoms undergoing combined endoscopy and direct laryngoscopy for the evaluation of symptoms. The direct laryngoscopy was performed and videotaped for blinded scoring by 3 otolaryngologists and an impedance catheter was placed onto the posterior larynx to obtain measurements. Following this, an endoscopy was performed and impedance measurements and biopsies were taken at 3 esophageal heights. Impedance values were compared within and between patients.

RESULTS

Eighty-eight patients were recruited, of which 73 had complete airway and endoscopic exams. There was no significant correlation between airway impedance values and mean reflux finding scores (r² = 0.45, P = .07). There was no significant positive correlation between airway impedance and esophageal impedance values (r² = 0.097-0.138, P > .2). Patients taking proton pump inhibitors had significantly lower mean airway impedance values (706 ± 450 Ω) than patients not taking them (1069 ± 809 Ω, P = .06). Patients who had evidence of aspiration on video fluoroscopic swallow studies had lower airway impedance (871 ± 615 Ω) than patients without aspiration (1247 ± 360 Ω, P = .008). Inhaled steroids did not impact airway impedance levels (P = .7).

CONCLUSIONS

Airway impedance may be an important diagnostic tool to diagnose gastroesophageal reflux or aspiration, eliminating the subjectivity of airway appearance alone.

The effects of Helicobacter pylori eradication therapy on salivary pepsin concentration in patients with laryngopharyngeal reflux

OBJECTIVE

To investigate the effect of Helicobacter pylori (HP) eradication therapy on salivary pepsin concentration in laryngopharyngeal reflux (LPR) patients with HP infection.

MATERIALS AND METHODS

A total of 477 patients with suspected LPR were enrolled from June 2020 to September 2021. Reflux symptom index, reflux finding score, the positive rates and disintegrations per minute values of HP infection detected by ¹⁴C urea breath test and salivary pepsin concentrations analyzed using enzyme-linked immunosorbent assay were compared in LPR patients and non-LPR patients with or without HP infection. HP-positive patients were treated with HP eradication therapy while HP-negative patients with PPI therapy.

RESULTS

The scores of nagging cough (0.88 vs. 0.50, P = 0.035), erythema or hyperemia (1.93 vs. 1.78, P = 0.035) and vocal fold edema (1.04 vs. 0.85, P = 0.025) were higher in the LPR (+) Hp (+) subgroup than in LPR (+) Hp (-) subgroup. The concentrations of salivary pepsin in the Hp (+) subgroup were higher than in the Hp (-) subgroup either in LPR patients (75.24 ng/ml vs. 61.39 ng/ml, P = 0.005) or the non-LPR patients (78.42 ng/ml vs. 48.96 ng/ml, P = 0.024). Compared to baseline (before treatment), scores of nagging cough (0.35 vs. 0.84, P = 0.019) and erythema or hyperemia (1.50 vs. 1.83, P = 0.039) and the concentrations of salivary pepsin (44.35 ng/ml vs. 74.15 ng/ml, P = 0.017) in LPR patients with HP infection decreased after HP treatment; yet, this was not observed for the LPR patients without HP infection treated with PPI only (P > 0.05).

CONCLUSION

HP infection may aggravate the symptoms and signs of LPR patients, partly by increasing their salivary pepsin concentration.

[The effect of expression of pepsin in vocal polyps on postoperative curative effect]

Objective:To investigate the effect of tissue pepsin expression of vocal polyps on the postoperative curative effect. Methods:Retrospectively analyze the data of 112 patients diagnosed with vocal cord polyps and undergone surgery from June 2019 to March 2021. The cases were divided into positive group and negative group according to the immunohistochemical pepsin expression. The preoperative reflux symptom index （RSI） and the reflux finding score （RFS） were compared, and the recovery of the voice acoustic function and postoperative vocal cord morphology were analyzed. Results:Among the postoperative specimens of 112 patients,76 cases were positive for pepsin staining, accounting for 67.9%, and 36 cases were negative, accounting for 32.1%. In the pepsin-positive group, 48 cases of vocal cord morphology returned to normal, and 20 cases remained scar or edema in the operation area, 8 cases of polyps relapsed; in the pepsin-negative group, a total of 32 cases of vocal cord morphology returned to normal, 4 cases of remained scar or edema in the operation area, no relapsed cases, the difference in vocal cord morphology recovery was significant （χ²=8.689, P=0.013）. The symptoms of hoarseness improved after 12 weeks. The differences between pre and post operative of G grade, VHI, MPT, fundamental frequency perturbation and amplitude perturbation assessed by GRBAS were significant （P<0.05）; postoperative G grade, VHI, MPT, fundamental frequency perturbation and amplitude perturbation were compared between the pepsin-positive group and the pepsin-negative group, and the differences were significant （all P<0.05）. Conclusion:The expression of pepsin in vocal polyps is a significant clinical indicator that affects the acoustic effect and morphological recovery of vocal cords after surgery. For patients with positive expression, acid suppression treatment should be strengthened after surgery.