Relationship Between Pepsin Expression and Dysplasia Grade in Patients With Vocal Cord Leukoplakia

Tracheobronchial mucosal keratosis: A literature review of this rare disorder

Background

Tracheobronchial mucosal keratosis (TBMK) is a rare airway disease that may cause refractory cough and airway stenosis. The characteristics of this disease remain unknown. In the present study, we describe this disorder based on a review of the current literature, emphasizing its diagnostic and therapeutic aspects.

Methods

A comprehensive search of TBMK was performed in Medline, Google Scholar, Web of Science, Cochrane Library (UK), Embase, China National Knowledge Infrastructure (CNKI) (China), and Wan Fang Med Online (China). The following data were collected: patient characteristics, chest imaging findings, bronchoscopy, histopathologic findings, pathogen testing, treatment, and prognosis.

Results

As of 2023, eighteen cases of TBMK have been reported. The main clinical manifestations were cough and expectoration. Chest imaging findings were non-specific. The main bronchoscopy findings were nodular protrusion of airway lumen and yellow-white purulent moss above the nodular lesion. The lesions were mainly located in the trachea and mainstem bronchus. The main pathological manifestations include keratinocytes or keratinocyte beads, squamous metaplasia, and mucosal inflammatory changes. The treatments that were administered include antibiotics, symptomatic treatment, and glucocorticoids. All methods were ineffective except for bronchoscopy-guided high-frequency electric knife and recombinant human epidermal growth factor treatment.

Conclusions

TBMK is a rare respiratory disease with atypical clinical manifestations and chest computed tomography findings. Bronchoscopy revealed that nodular hyperplasia of the airway and purulent fur-covered lesions are typical manifestations. The final diagnosis needs to be confirmed by histopathological examination. There is a lack of effective treatment for this disease, and bronchoscopy-guided intervention therapy may be a candidate treatment.

Pepsin Increases the Proliferation of Vocal Cord Leukoplakia Epithelial Cells by Inducing Autophagy

OBJECTIVE

To investigate the role of H+ /K+ ATPase in the proliferation of pepsin-induced vocal cord leukoplakia (VCL) cells.

STUDY DESIGN

Translation research.

SETTING

Affiliated Hospital of University.

METHODS

Immunohistochemistry was used to detect pepsin, H+ /K+ ATPase (ATP4A and ATP4B subunits) in VCL cells with varying degrees of dysplasia. After primary cultures of VCL cells had been established, the effects of acidified pepsin on the proliferation, autophagy, and H+ /K+ -ATPase distribution of VCL cells were investigated.

RESULTS

The levels of pepsin, ATP4A, and ATP4B were significantly higher in VCL tissue with moderate-to-severe dysplasia than in normal tissue (p < .05); these levels gradually increased according to dysplasia severity. The expression levels of ATP4A and ATP4B were significantly correlated with the amount of pepsin in VCL cells (p < .01). Acidified pepsin enhanced the levels of proliferation and autophagy in human VCL epithelial cells. The cloning- and autophagy-promoting effects of acidified pepsin on VCL cells were partially reversed by pantoprazole; these effects were completely blocked by the autophagy inhibitor chloroquine. Finally, acidified pepsin promoted the colocalization of H+ /K+ -ATPase and lysosomes in VCL cells; it also mediated lysosome acidification.

CONCLUSION

Pepsin and H+ /K+ -ATPase may contribute to the progression of VCL. Specifically, acidified pepsin may regulate lysosome acidification by promoting lysosomal localization of H+ /K+ -ATPase.

Pepsin enhances glycolysis to promote malignant transformation of vocal fold leukoplakia epithelial cells with dysplasia

PURPOSE

The mechanism underlying malignant transformation of vocal fold leukoplakia (VFL) and the precise role of the expression of pepsin in VFL remain unclear. This study aimed to investigate the effects of acidified pepsin on VFL epithelial cell growth and migration, and also identify pertinent molecular mechanisms.

METHODS

Immunochemistry and Western blotting were performed to measure glucose transporter type 1 (GLUT1), monocarboxylate transporters 4 (MCT4), and Hexokinase-II (HK-II) expressions. Cell viability, cell cycle, apoptosis, and migration were investigated by CCK-8 assay, flow cytometry and Transwell chamber assay, respectively. Glycolysis-related contents were determined using the corresponding kits. Mitochondrial HK-II was photographed under a confocal microscope using Mito-Tracker Red.

RESULTS

It was found: the expression of pepsin and proportion of pepsin+ cells in VFL increased with the increased dysplasia grade; acidified pepsin enhanced cell growth and migration capabilities of VFL epithelial cells, reduced mitochondrial respiratory chain complex I activity and oxidative phosphorylation, and enhanced aerobic glycolysis and GLUT1 expression in VFL epithelial cells; along with the transfection of GLUT1 overexpression plasmid, 18FFDG uptake, lactate secretion and growth and migration capabilities of VFL epithelial cell were increased; this effect was partially blocked by the glycolysis inhibitor 2-deoxy-glucose; acidified pepsin increased the expression of HK-II and enhanced its distribution in mitochondria of VFL epithelial cells.

CONCLUSION

It was concluded that acidified pepsin enhances VFL epithelial cell growth and migration abilities by reducing mitochondrial respiratory complex I activity and promoting metabolic reprogramming from oxidative phosphorylation to aerobic glycolysis.

Dysplastic Lesions of the Larynx

There have been many advancements in the clinical and histologic diagnosis of laryngeal dysplasia (LD), but diagnosis still necessitates invasive histologic evaluation. Furthermore, despite improved histologic identification of dysplastic lesions, the exact details of pathophysiologic progression and the risk of malignant transformation is still uncertain. These unknowns create a barrier to establishing an ideal grading and classification system, which prevents the establishment of a precise and consistent treatment paradigm. Identifying these gaps in knowledge serves to highlight where further studies are warranted, ideally focusing on a better understanding of the biological behavior of LD. This would ultimately allow for the creation of a reliable grading and classification system and for the formalization of management and treatment guidelines for LD.

Accuracy of narrow‐band imaging for diagnosing malignant transformation of vocal cord leukoplakia: A systematic review and meta‐analysis

Objective

To explore whether narrow-band imaging (NBI) endoscopy is accurate in the diagnosis of malignant transformation of vocal cord leukoplakia.

Methods

The PubMed, Embase, Cochrane Library and Web of Science databases were searched to collect data on studies reporting the use of NBI endoscopy as a diagnostic test for diagnosing vocal cord leukoplakia from January 2015 to December 2021. Study design, analysis method, and extraction results were performed according to the PRISMA guidelines. The sensitivity, specificity, pooled positive likelihood ratio (PLR), negative likelihood ratio (NLR) and area under the curve (AUC) were used to summarize the performance metrics of the meta-analysis. Risk of bias data and the quality of the included studies was evaluated according to the Quality Assessment of Diagnostic Accuracy Studies-2 tool (QUADAS-2).

Results

Nine studies were finally included in the analysis. The results of the meta-analysis showed that the pooled sensitivity and specificity of NBI endoscopy for diagnosing leukoplakia lesions were 0.76 (95% CI: 0.72-0.8) and 0.93 (95% CI: 0.91-0.95), respectively. The PLR and NLR were 10.09 (95% CI: 6.53-15.59) and 0.22 (95% CI: 0.13-0.38), respectively. The comprehensive diagnostic odds ratio (DOR) was 54.96 (95% CI: 24.32-124.17), and the area under the curve was 0.9584. The eight articles had a low risk of bias risk and one article was unclear.

Conclusion

NBI likely has good accuracy for diagnosing malignant transformation of vocal cord leukoplakia. However, multicenter studies and large samples are still needed.

Videolaryngoendoscopic and Stroboscopic Evaluation in Predicting the Malignancy Risk of Vocal Fold Leukoplakia

Background: Vocal fold leukoplakia (VFL), despite our knowledge of its etiopathogenetic factors, and the development of laryngeal visualization, remains a diagnostic and therapeutic challenge. Objective: This research aimed to explore the efficacy of clinical and morphological feature identification in videolaryngoendoscopy (VLE) using a three-tier classification, and videolaryngostroboscopy (VLS) in predicting the risk of VFL malignant transformation. Material and Methods: We examined 98 patients with VFL by flexible endoscopy under VLE and VLS. Morphological characteristics of 123 lesions including the surface, margin, and texture were assessed; then, VFL was subdivided into three types: I—flat and smooth, II—elevated and smooth, and III—rough. Based on the histopathological findings, 76 (61.79%) lesions were classified as low- and 47 (38.21%) lesions as high-grade dysplasia. Results: The inter-rater agreement between two raters evaluating the VFL in VLE was almost perfect (Cohen’s kappa = 0.826; p < 0.00; 95%CI 0.748−0.904). In ROC curve analysis, the AUC difference between Rater I and Rater II was 0.024 (0.726 vs. 0.702). In multivariate analysis, high-risk VFL was positively related to unilateral plaque localization (p = 0.003), the type III VLE classification (p = 0.013), absence of a mucosal wave (p = 0.034), and a positive history of alcohol consumption (p = 0.047). In ROC analysis, VLE had an AUC of 0.726, with a high sensitivity of 95.7% and low specificity of 40.8%. The NPV was high, at 93.9%; however, the PPV was low, at 50%. The proposed logistic regression model including features significant in multivariate analysis showed lower sensitivity (80.9% vs. 95.7%) and lower NPV (86.2% vs. 93.9%); however, the specificity and PPV were improved (73.7% vs. 40.8% and 65.5% vs. 50.0%, respectively). Conclusions: The combination of clinical history with endoscopic (plaque morphology) and stroboscopic examination (mucosal wave assessment) can fairly estimate the degree of dysplasia in VFL and thus is recommended for use in clinical settings. The findings of this study can be used to guide the decision regarding immediate biopsy or watchful waiting.

Does hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring for the diagnosis of laryngopharyngeal reflux have to be 24 h?

PURPOSE

To investigate the diagnostic value of combined multi-timepoint salivary pepsin testing (MTPSPT) and hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring (HEMII-pH) for laryngopharyngeal reflux (LPR) and whether an appropriate reduction in the duration of HEMII-pH would affect the accuracy of diagnosis of LPR.

METHODS

Recruited patients were studied with both MTPSPT and HEMII-pH. The diagnosis of LPR was based on the occurrence of > 1 reflux event and/or positive results on any of the MTPSPT. The diagnostic value of combined diagnosis was studied through combining a breakdown of the 24-h HEMII-pH finding and the results of the MTPSPT. The diagnostic value was expressed in terms of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

RESULTS

Based on 24-h HEMII-pH and MTPSPT, the positive rate of LPR was 83.33% and 74.69%, respectively. According to the combined diagnosis, the positive rate of LPR was 90.74%. The sensitivity and specificity of the combined diagnosis both were 89.51% and 100%, when the HEMII-pH intervals were 7 a.m.-6 p.m. and 7 a.m.-7 p.m., respectively. However, when the monitoring time was extended to 8 p.m. and bedtime, the sensitivity, specificity, PPV and NPV of the combined diagnosis both were 100%.

CONCLUSIONS

The combination of MTPSPT and HEMII-pH increased the sensitivity and accuracy of diagnosis of LPR. For patients with positive MTPSPT results, the duration of HEMII-pH can be appropriately shortened to reduce patient sufferings.

Clinical Update Findings about pH-Impedance Monitoring Features in Laryngopharyngeal Reflux Patients

Purpose: The diagnosis of laryngopharyngeal reflux (LPR) is commonly based on non-specific symptoms and findings and a positive response to an empirical therapeutic trial. The therapeutic response is, however, unpredictable, and many patients need pH-impedance monitoring to confirm the diagnosis. Methods: A review of the recent literature was conducted in PubMED, Scopus, and Embase about the pH-study features of LPR patients. A summary of last evidence was proposed. Results: The awareness of otolaryngologists about indications and interpretation of pH-impedance monitoring is low. The hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring (HEMII-pH) is the most reliable examination determining the type and composition of hypopharyngeal reflux events (HRE) and the LPR features. The use of HEMII-pH is important to confirm the diagnosis in selected patients because non-specificity of symptoms and findings. There are no international consensus guidelines for the LPR diagnosis at the HEMII-pH. However, most studies supported the occurrence of >1 acid/weakly acid/nonacid HRE as diagnostic threshold. HREs are more frequently gaseous, weakly/nonacid compared with reflux events of gastroesophageal reflux. HREs occurred as daytime and upright, which does not support the value of double proton pump inhibitors or bedtime alginate. Oropharyngeal pH-monitoring is another approach reporting different sensitivity and specificity outcomes from HEMII-pH. The use of Ryan score for the LPR diagnosis at the oropharyngeal pH monitoring may be controversial regarding the low consideration of alkaline HREs. Conclusions: The awareness of otolaryngologists about HEMII-pH indication, features, and interpretation is an important issue regarding the high prevalence of LPR in outpatients consulting in otolaryngology. The HEMII-pH findings may indicate a more personalized treatment considering type and occurrence time of HREs.

The role of Glut-1 and H+/K+-ATPase expression in hyperplasia of mice laryngeal epithelium induced by pepsin

Purpose

To explore the role played by Glut-1 and H⁺/K⁺-ATPase in pepsin-induced, mouse laryngeal epithelial proliferation, growth, and development.

Methods

We established a mouse model of laryngopharyngeal reflux and measured Glut-1 and H⁺/K⁺-ATPase expression levels in mouse laryngeal epithelium treated with artificial gastric juice containing pepsin.

Results

Artificial pepsin-containing gastric juice induced significant hyperplastic changes in mouse laryngeal epithelium compared to control mice at 15, 30, and 45 days. Inhibition of Glut-1 expression by 2-DG significantly suppressed such hyperplasia compared to mice exposed to artificial gastric juice containing pepsin at 15, 30, and 45 days. After treatment with pepsin-containing artificial gastric juice, RT-PCR and Western blotting showed that the levels of Glut-1 and H⁺/K⁺-ATPase α, β increased significantly.

Conclusions

Pepsin-containing artificial gastric juice promoted mouse laryngeal epithelial hyperplasia associated with abnormal expression of Glut-1 and H⁺/K⁺-ATPase α, β.

Role and mechanism of Glut-1 and H+/K+-ATPase expression in pepsin-induced development of vocal cord leukoplakia

PURPOSE

We investigated the role of Glut-1 and H⁺/K⁺-ATPase expression in pepsin-induced development of human vocal cord leukoplakia cells (HVCLCs). Next, we analyzed the relationship between Glut-1 and H⁺/K⁺-ATPase expression with the clinicopathological features of laryngeal carcinoma.

METHODS

Glut-1 and H⁺/K⁺-ATPase expression levels in HVCLCs were determined after treatment with artificial gastric juice containing pepsin and laryngeal carcinoma tissues.

RESULTS

Exposure to pepsin-containing artificial gastric juice significantly enhanced the migration and proliferation of VSCLCs in a time-dependent manner. The apoptotic rate of VSCLCs decreased over time after exposure to pepsin and reached a nadir on day 7 (p < 0.01). With increasing duration of exposure to pepsin, the proportion of VSCLCs in G0/G1 phase decreased and the proportions in the S and G2/M phases significantly increased (p < 0.05). After treatment with pepsin-containing artificial gastric juice, RT-PCR and Western blotting showed that the expression of Glut-1 and H⁺/K⁺-ATPase α, β significantly increased in HVCLCs compared to in the absence of pepsin (p < 0.05). The expression of Glut-1 and H⁺/K⁺-ATPase α, β gradually increased from vocal cord leukoplakia (VLC) to laryngeal carcinoma (p < 0.05). Lentivirus-mediated inhibition of Glut-1 expression in VCL significantly inhibited the cells' migration and proliferation (p < 0.05) but enhanced their apoptosis (p < 0.05). Also, inhibition of Glut-1 expression resulted in an increased proportion of cells in G0/G1 phase and a significantly decreased proportion in G2/M phase (p < 0.05).

CONCLUSIONS

Elevated Glut-1 expression may promote the development of VCL by upregulating laryngeal H⁺/K⁺-ATPase expression to reactivate absorbed pepsin, thus damaging the laryngeal mucosa.

Association of Pepsin With Inflammatory Signaling and Effusion Viscosity in Pediatric Otitis Media

OBJECTIVE

Otitis media (OM) is a common inflammatory disease spectrum. Cytokine signaling, neutrophil activity, and mucin hypersecretion during recurrent and chronic OM contribute to persistent, viscous middle ear (ME) effusions, hearing loss, and potential for developmental delay. Extraesophageal reflux (EER), specifically pepsin, triggers inflammatory signaling in respiratory mucosa and is associated with OM. The objective of this study was to investigate the association of pepsin with ME inflammatory signaling and the outcomes and examine causality in vitro.

STUDY DESIGN

Cross-sectional study.

METHODS

ME fluid (MEF) and preoperative audiometric data were collected from 30 pediatric subjects undergoing tympanostomy tube placement for recurrent OM or OM with effusion. MEF viscosity was characterized by the surgeon. Pepsin, inflammatory molecules, and mucin were assayed by enzyme-linked immunosorbent assay (ELISA). ME epithelial primary culture was exposed to 0.1 to 1 mg/ml pepsin at pH 5, 6, and 7 for 30 minutes, and cytokine expression was assayed via qPCR.

RESULTS

Pepsin was observed in the MEF of 77% of patients (range 71-2,734 ng/ml). Pepsin correlated with effusion viscosity, interleukins -6 and -8, neutrophil elastase, and mucin 5B (P < .05). Pepsin-negative MEF was more frequently absent of interleukin 8 or mucin 5B (P < .05). Weak acid was generally insufficient to elicit cytokine expression in ME cells in vitro, however, pepsin induced IL6, IL8, and TNF at pH 7 (P < .05) and weak acid (pH 6) facilitated a response at lower pepsin concentration.

CONCLUSIONS

Pepsin may contribute to inflammatory signaling, persistent viscous effusion, and poorer OM outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.