Fundoplication for laryngopharyngeal reflux despite preoperative dysphagia

Inhaled fosamprenavir for laryngopharyngeal reflux: Toxicology and fluid dynamics modeling

Objectives

Approximately 25% of Americans suffer from laryngopharyngeal reflux (LPR), a disease for which no effective medical therapy exists. Pepsin is a predominant source of damage during LPR and a key therapeutic target. Fosamprenavir (FOS) inhibits pepsin and prevents damage in an LPR mouse model. Inhaled FOS protects at a lower dose than oral; however, the safety of inhaled FOS is unknown and there are no inhalers for laryngopharyngeal delivery. A pre-Good Lab Practice (GLP) study of inhaled FOS was performed to assess safety and computational fluid dynamics (CFD) modeling used to predict the optimal particle size for a laryngopharyngeal dry powder inhaler (DPI).

Methods

Aerosolized FOS, amprenavir (APR), or air (control) were provided 5 days/week for 4 weeks (n = 6) in an LPR mouse model. Organs (nasal cavity, larynx, esophagus, trachea, lung, liver, heart, and kidney) were assessed by a pathologist and bronchoalveolar lavage cytokines and plasma cardiotoxicity markers were assessed by Luminex assay. CFD simulations were conducted in a model of a healthy 49-year-old female.

Results

No significant increase was observed in histologic lesions, cytokines, or cardiotoxicity markers in FOS or APR groups relative to the control. CFD predicted that laryngopharyngeal deposition was maximized with aerodynamic diameters of 8.1-11.5 μm for inhalation rates of 30-60 L/min.

Conclusions

A 4-week pre-GLP study supports the safety of inhaled FOS. A formal GLP assessment is underway to support a phase I clinical trial of an FOS DPI for LPR.

Level of Evidence

NA.

Amprenavir inhibits pepsin-mediated laryngeal epithelial disruption and E-cadherin cleavage in vitro

Background

Laryngopharyngeal reflux (LPR) causes chronic cough, throat clearing, hoarseness, and dysphagia and can promote laryngeal carcinogenesis. More than 20% of the US population suffers from LPR and there is no effective medical therapy. Pepsin is a predominant source of damage during LPR which disrupts laryngeal barrier function potentially via E-cadherin cleavage proteolysis and downstream matrix metalloproteinase (MMP) dysregulation. Fosamprenavir (FDA-approved HIV therapeutic and prodrug of amprenavir) is a pepsin-inhibiting LPR therapeutic candidate shown to rescue damage in an LPR mouse model. This study aimed to examine amprenavir protection against laryngeal monolayer disruption and related E-cadherin proteolysis and MMP dysregulation in vitro.

Methods

Laryngeal (TVC HPV) cells were exposed to buffered saline, pH 7.4 or pH 4 ± 1 mg/mL pepsin ± amprenavir (10-60 min). Analysis was performed by microscopy, Western blot, and real time polymerase chain reaction (qPCR).

Results

Amprenavir (1 μM) rescued pepsin acid-mediated cell dissociation (p < .05). Pepsin acid caused E-cadherin cleavage indicative of regulated intramembrane proteolysis (RIP) and increased MMP-1,3,7,9,14 24-h postexposure (p < .05). Acid alone did not cause cell dissociation or E-cadherin cleavage. Amprenavir (10 μM) protected against E-cadherin cleavage and MMP-1,9,14 induction (p < .05).

Conclusions

Amprenavir, at serum concentrations achievable provided the manufacturer's recommended dose of fosamprenavir for HIV, protects against pepsin-mediated cell dissociation, E-cadherin cleavage, and MMP dysregulation thought to contribute to barrier dysfunction and related symptoms during LPR. Fosamprenavir to amprenavir conversion by laryngeal epithelia, serum and saliva, and relative drug efficacies in an LPR mouse model are under investigation to inform development of inhaled formulations for LPR.

Oral and Inhaled Fosamprenavir Reverses Pepsin-Induced Damage in a Laryngopharyngeal Reflux Mouse Model

OBJECTIVE

More than 20% of the US population suffers from laryngopharyngeal reflux. Although dietary/lifestyle modifications and alginates provide benefit to some, there is no gold standard medical therapy. Increasing evidence suggests that pepsin is partly, if not wholly, responsible for damage and inflammation caused by laryngopharyngeal reflux. A treatment specifically targeting pepsin would be amenable to local, inhaled delivery, and could prove effective for endoscopic signs and symptoms associated with nonacid reflux. The aim herein was to identify small molecule inhibitors of pepsin and test their efficacy to prevent pepsin-mediated laryngeal damage in vivo.

METHODS

Drug and pepsin binding and inhibition were screened by high-throughput assays and crystallography. A mouse model of laryngopharyngeal reflux (mechanical laryngeal injury once weekly for 2 weeks and pH 7 solvent/pepsin instillation 3 days/week for 4 weeks) was provided inhibitor by gavage or aerosol (fosamprenavir or darunavir; 5 days/week for 4 weeks; n = 3). Larynges were collected for histopathologic analysis.

RESULTS

HIV protease inhibitors amprenavir, ritonavir, saquinavir, and darunavir bound and inhibited pepsin with IC50 in the low micromolar range. Gavage and aerosol fosamprenavir prevented pepsin-mediated laryngeal damage (i.e., reactive epithelia, increased intraepithelial inflammatory cells, and cell apoptosis). Darunavir gavage elicited mild reactivity and no discernable protection; aerosol protected against apoptosis.

CONCLUSIONS

Fosamprenavir and darunavir, FDA-approved therapies for HIV/AIDS, bind and inhibit pepsin, abrogating pepsin-mediated laryngeal damage in a laryngopharyngeal reflux mouse model. These drugs target a foreign virus, making them ideal to repurpose. Reformulation for local inhaled delivery could further improve outcomes and limit side effects.

LEVEL OF EVIDENCE

NA. Laryngoscope, 133:S1-S11, 2023.

Surgical Treatment for Laryngopharyngeal Reflux Disease: A Systematic Review

Importance

Laryngopharyngeal reflux (LPR) is a prevalent disease that is usually treated with diet, lifestyle modifications, and proton pump inhibitor therapy. However, nearly 10% to 30% of patients do not achieve adequate acid suppression even with high doses of proton pump inhibitors. For these patients with resistant disease, fundoplication may be recommended but the success rate of fundoplication surgery on laryngopharyngeal symptoms and findings remains uncertain.

Objective

To determine whether fundoplication is associated with control of signs and symptoms in patients with LPR.

Evidence Review

A literature search was conducted on PubMed, Cochrane Library, and Scopus according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guideline to identify studies published between 1990 and 2018 about the efficacy of fundoplication on clinical outcomes of LPR. Three investigators screened publications for eligibility and exclusion based on predetermined criteria. Study design, patient characteristics, diagnostic method, exclusion criteria, treatment characteristics, follow-up, and quality of the outcome assessment were evaluated.

Findings

Of the 266 studies identified, 34 met the inclusion criteria, accounting for 2190 patients with LPR (1270 women and 920 men; mean [SD] age at the time of surgery, 49.3 [6.3] years). A weighted mean of 83.0% of patients (95% CI, 79.7%-86.3%) experienced improvement and a weighted mean of 67.0% of patients (95% CI, 64.1%-69.9%) experienced a disappearance of symptoms, but there is a high level of methodological heterogeneity among studies according to diagnostic method, exclusion criteria, and outcomes used to assess the efficacy of fundoplication. A pH study without impedance study was used in most studies but with various inclusion criteria. According to results of an a priori assessment, the clinical outcomes used were overall poor, excluding many symptoms and findings associated with LPR.

Conclusion and Relevance

The reported studies of fundoplication in LPR disease have important heterogeneity in method of diagnosis, exclusion criteria, symptoms, and signs assessed as therapeutic outcomes; therefore, this systematic review was nonconclusive regarding whether surgery for LPR disease is associated with effective control of sight and symptoms. Otolaryngologists, gastroenterologists, and surgeons must establish a diagnostic criterion standard, clear indications for surgery, and future clinical outcomes to precisely assess the effectiveness of treatment.

Proximal reflux: biochemical mediators, markers, therapeutic targets, and clinical correlations

Airway reflux is implicated in the pathophysiology of a wide range of adult and pediatric upper and lower airway diseases. However, the diagnosis of proximal reflux-associated disease remains challenging due to evolving clinical criteria and institutional and regional variances in diagnostic practices. Evidence suggests that nonacidic contents of reflux may serve as both pathologic mediators of and biomarkers for reflux in the upper airway. Furthermore, they offer potential pharmaceutical and surgical intervention targets and are the focus of novel clinical diagnostic tools currently under investigation.

Magnetic sphincter augmentation is an effective treatment for atypical symptoms caused by gastroesophageal reflux disease

BACKGROUND

The purpose of this study was to determine whether magnetic sphincter augmentation (MSA) could effectively treat patients with gastroesophageal reflux disease (GERD) who suffer primarily from atypical symptoms due to laryngopharyngeal reflux (LPR). MSA has been shown to treat typical symptoms of GERD with good success, but its effect on atypical symptoms is unknown.

METHODS

A retrospective review of a prospectively maintained institutional review board-approved database was conducted for all patients who underwent MSA between January 2015 and December 2018. All patients had objective confirmation of GERD from ambulatory pH monitoring off anti-reflux medications (DeMeester score > 14.7). Symptoms were assessed preoperatively and at 1 year postoperatively using GERD Health-Related Quality of Life (GERD-HRQL) and Reflux Symptom Index (RSI) questionnaires.

RESULTS

There were 86 patients (38 males; 48 females) with a median age of 51.5 years. Total GERD HRQL scores improved from a mean of 38.79 to 6.53 (p < 0.01) and RSI scores improved from a mean of 20.9 to 8.1 (p < 0.01). Atypical symptoms evaluated from the RSI questionnaire include hoarseness, throat clearing, postnasal drip, breathing difficulties, and cough. All atypical symptoms were significantly improved at 1 year following MSA (p < 0.01). All three typical symptoms of heartburn, dysphagia, and regurgitation were significantly improved based on pre and postoperative GERD HRQL questionnaires (p < 0.02). Ninety-one percent of patients were off their PPI and dissatisfaction with their current therapy decreased from 95% preoperatively to 13% postoperatively.

CONCLUSION

MSA is an effective treatment for typical and atypical GERD symptoms.