Effect of pepsin on laryngeal stress protein (Sep70, Sep53, and Hsp70) response: role in laryngopharyngeal reflux disease

Reevaluation of gastroesophageal reflux disease as a risk factor for laryngeal cancer

OBJECTIVES/HYPOTHESIS

The relationship between gastroesophageal reflux disease (GERD) and laryngeal cancer has not been fully elucidated. This case-control study investigates whether GERD increases the odds of developing these malignancies.

STUDY DESIGN

Case-control study.

METHODS

Rates of GERD among cases of laryngeal cancer identified in the Veterans Health Administration outpatient care files (year 2000-2006) were compared with controls. Cases (N = 14,449) were frequency matched 1:1 with controls. Multivariate logistic regression was used to determine the association between GERD and cancer.

RESULTS

After adjusting for tobacco and/or alcohol use, there was no association between GERD and laryngeal cancer (adjusted odds ratio, 1.01; 95% confidence interval, 0.92-1.12, P =.780). Although an association was found when time from GERD diagnosis to malignancy was less than 3 months, it disappeared when this period was extended further.

CONCLUSIONS

In this population, there was no increased risk of laryngeal cancer among patients with GERD. However, in subsite analysis, a possible relationship between GERD and glottic cancer was observed. Reverse causality must be considered in future studies assessing the relationship between reflux and laryngeal cancer to limit misclassification bias.

Analysis of Pepsin in Tracheoesophageal Puncture Sites

Objectives:

Tracheoesophageal puncture (TEP) and prosthesis insertion is a well-established method of voice rehabilitation after laryngectomy. Maintenance of the prosthesis and tract can be challenging, and reflux to the TEP site has been proposed as a cause. The sites of TEP were evaluated for the presence of pepsin in tissue biopsy specimens and tract secretions to explore this association.

Methods:

Patients with TEP were interviewed for a history of symptoms related to reflux, medication use history, TEP voice quality, and incidence of TEP complications. Tissue biopsy specimens and tract secretions were obtained from TEP sites and analyzed for the presence of pepsin via sodium dodecyl sulfate–polyacrylamide gel electrophoresis Western blot analysis.

Results:

Twelve of 17 patients (47%) had some history of preoperative or postoperative symptoms of gastroesophageal reflux disease or laryngopharyngeal reflux. Pepsin was present within the TEP site in a total of 10 of 17 patients (58%; 7 of 17 tissue biopsy specimens and 6 of 7 secretion samples). There were no statistically significant associations between the presence of pepsin and sex, reflux history, use of acid suppressive medicine, or time since laryngectomy.

Conclusions:

Reflux with subsequent pepsin deposition into the TEP tract occurs in a majority of laryngectomy patients. Further studies on the effect of reflux on the health and function of the TEP tract are warranted.

Altered expression of HSP27 and HSP70 in distal oesophageal mucosa in patients with gastro-oesophageal reflux disease subjected to fundoplication

BACKGROUND

Gastro-oesophageal reflux disease (GERD) is a risk factor for oesophageal adenocarcinoma. Although fundoplication cures reflux symptoms and oesophagitis, it remains controversial whether it is capable of preventing the development of oesophageal adenocarcinoma. Hsp27 and Hsp70 are associated with the development of cancer, whereas the effect of fundoplication on them is not known.

METHODS

The expression of Hsp27 and Hsp70 was assessed semiquantitatively from biopsies of oesophageal mucosa for a prospective cohort of 19 patients with GERD treated with fundoplication and 7 controls without GERD. Upper gastrointestinal endoscopy with biopsies from the oesophagogastric junction (EGJ) and the distal and proximal oesophagus were performed preoperatively (19 patients) and after recovery from GERD at 6 (19 patients) and 48 months (16 patients) postoperatively.

RESULTS

The expressions of both Hsp27 (p = 0.001) and Hsp70 (p = 0.002) in the distal oesophagus were lower in patients preoperatively and at 48 months postoperatively (p < 0.001 for both) than in controls. The patients' Hsp27 and Hsp70 levels were lower preoperatively in the proximal oesophagus (p = 0.048 for both) than in controls. Both Hsp27 (p = 0.002) and Hsp70 (p = 0.003) were lower in the distal oesophagus preoperatively and at 48 months postoperatively (p = 0.003 for Hsp27, p = 0.004 for Hsp70) than in the proximal oesophagus.

CONCLUSIONS

Our results indicate that there may be some factor interfering with the mucosal defence system of the distal oesophagus in GERD that is uninfluenced by fundoplication and not associated with the acid-reflux-normalizing effect.

Simulated reflux decreases vocal fold epithelial barrier resistance

OBJECTIVES/HYPOTHESIS

The vocal fold epithelium provides a barrier to the entry of inhaled and systemic challenges. However, the location of the epithelium makes it vulnerable to damage. Past research suggests, but does not directly demonstrate, that exposure to gastric reflux adversely affects the function of the epithelial barrier. Understanding the nature of reflux-induced epithelial barrier dysfunction is necessary to better recognize the mechanisms for vocal fold susceptibility to this disease. Therefore, we examined the effects of physiologically relevant reflux challenges on vocal fold transepithelial resistance and gross epithelial and subepithelial appearance.

STUDY DESIGN

Ex vivo, mixed design with between-group and repeated-measures analyses.

METHODS

Healthy, native porcine vocal folds (N = 52) were exposed to physiologically relevant acidic pepsin, acid-only, or pepsin-only challenges and examined with electrophysiology and light microscopy. For all challenges, vocal folds exposed to a neutral pH served as control.

RESULTS

Acidic pepsin and acid-only challenges, but not pepsin-only or control challenges significantly reduced transepithelial resistance within 30 minutes. Reductions in transepithelial resistance were irreversible. Challenge exposure produced minimal gross changes in vocal fold epithelial or subepithelial appearance as evidenced by light microscopy.

CONCLUSIONS

These findings demonstrate that acidic environments characteristic of gastric reflux compromise epithelial barrier function without gross structural changes. In healthy, native vocal folds, reductions in transepithelial resistance could reflect reflux-related epithelial disruption. These results might guide the development of pharmacologic and therapeutic recommendations for patients with reflux, such as continued acid-suppression therapy and patient antireflux behavioral education.

Rationale for Targeting Pepsin in the Treatment of Reflux Disease

Objectives:

We undertook to 1) obtain unequivocal evidence to confirm or rebut our initial observations that pepsin is taken up by hypopharyngeal epithelial cells by receptor-mediated endocytosis, 2) investigate whether uptake of pepsin at pH 7, in nonacidic refluxate, is of pathological significance, and 3) test our hypothesis that inactive but stable pepsin (<pH 8) taken up by hypopharyngeal epithelial cells causes damage by becoming reactivated inside the cell.

Methods:

Human posterior cricoid biopsy specimens and cultured hypopharyngeal FaDu epithelial cells were used to perform competitive binding studies and to investigate colocalization of pepsin with clathrin, Rab-9, and TRG-46. FaDu cells were exposed to pepsin (both irreversibly and reversibly inactivated) in the presence and absence of wortmannin and dimethyl amiloride and analyzed by electron microscopy, MTT cytotoxicity assay, and Stress and Toxicity SuperArray.

Results:

Pepsin is unequivocally taken up by hypopharyngeal epithelial cells by receptor-mediated endocytosis. Uptake of pepsin at pH 7, in nonacidic refluxate, causes mitochondrial damage and changes the expression of several genes implicated in stress and toxicity. Irreversible, but not reversible, inhibition of peptic activity prevents these changes.

Conclusions:

Pepsin, at pH 7, in nonacidic refluxate, causes damage by becoming reactivated inside the cell. Irreversible inhibitors of peptic activity hold promise as a new therapy for reflux.

[Functional endoscopy : the physiological and pathophysiological basis of reflux disease, diagnosis and therapy]

ENT specialists and gastroenterologists are increasingly confronted with the question of how to recognize and evaluate extra-esophageal complications of reflux. Both specialities need to collaborate, since they are connected via the esophagus, and both need to know more about the speciality of their neighbor than was hitherto usual. This publication presents the observations and measurements of little-known physiological functions. This is followed by an attempt to define the border between healthy and diseased. Finally, the possible consequences of functional disorders are described. The leap from observation of function to the microcosm of biochemical links is discussed and supported using experimental work. This overview highlights the limitations of our current knowledge. The success of functional endoscopy in terms of therapeutic approaches is immense. The required therapy is finally based on a clear diagnostic concept; probatory therapy is a waste of money.

2D-DIGE proteomic characterization of head and neck squamous cell carcinoma

OBJECTIVE

Identify proteins that are differentially expressed between head and neck squamous cell cancer (HNSCC) and patient-matched normal adjacent tissue, and validate findings in a separate patient cohort.

STUDY DESIGN

Cross-sectional study of surgical specimens.

SETTING

Tertiary care academic medical center.

SUBJECTS AND METHODS

Laser capture microdissection and two-dimensional difference gel electrophoresis were used previously to establish proteomic profiles for tumor and normal adjacent tissue from 14 patients. Here, significance analysis of microarray was used to rank candidate biomarkers. Spots meeting statistical and biological criteria of significance were analyzed by liquid chromatography and tandem mass spectrometry to obtain protein identifications. The expression pattern of the highest-ranked candidate biomarker (cornulin) was validated in a larger, independent patient cohort (n = 68) by immunohistochemical staining of a tissue microarray.

RESULTS

Of 732 spots, 117 (15.9%) met criteria for significance. Identities were obtained for 39 spots, representing 17 different proteins. Four proteins were novel in the context of HNSCC: glutathione synthetase, which was upregulated; and cornulin (squamous epithelial heat shock protein 53), guanylate binding protein 6, and heat shock 70 kDa protein 5 (glucose-regulated protein, 78 kDa), which were downregulated. Cornulin functions in the stress response in normal squamous epithelium, and reduced expression has been proposed as a marker of susceptibility to laryngopharyngeal reflux and other stressors. Loss of cornulin expression was confirmed in an independent HNSCC patient cohort (P < 0.001).

CONCLUSIONS

Downregulation of cornulin is a prominent feature of the molecular signature of HNSCC identified by comparative proteomics. Cornulin may represent a link between HNSCC and other pathologies arising in stratified squamous epithelium.

Pepsin in nonacidic refluxate can damage hypopharyngeal epithelial cells

OBJECTIVES

Studies using combined multichannel intraluminal impedance with pH monitoring reveal a role for nonacidic reflux in laryngopharyngeal symptoms and injury. We have discovered that pepsin is taken up by laryngeal epithelial cells by receptor-mediated endocytosis. This finding reveals a novel mechanism by which pepsin could cause cell damage, potentially even in nonacidic refluxate. The objective of this study was to determine whether pepsin, at pH 7.4 and thus in nonacidic refluxate, causes cell damage.

METHODS

Cultured hypopharyngeal epithelial (FaDu) cells were exposed to human pepsin (0.1 mg/mL) at pH 7.4 for either 1 hour or 12 hours at 37 degrees C and analyzed by electron microscopy, cytotoxicity assay, and SuperArray.

RESULTS

We report mitochondrial and Golgi complex damage in cells exposed to pepsin at neutral pH, observed by electron microscopy. We also report cell toxicity of pepsin at pH 7.4, measured by a cytotoxicity assay. Furthermore, using SuperArray, we found that pepsin at pH 7.4 significantly alters the expression levels of multiple genes implicated in stress and toxicity.

CONCLUSIONS

These findings are perhaps the first to explain why many patients have symptoms and injury associated with nonacidic reflux, and could have important implications for the development of new therapies for reflux, such as pepsin receptor antagonists and/or irreversible inhibitors of peptic activity.

Laryngopharyngeal reflux: current concepts and questions

PURPOSE OF REVIEW

Laryngopharyngeal reflux is a widely recognized disorder. Yet, decades after its initial description, debate persists regarding pathophysiology, diagnosis, and treatment. This review addresses current literature on laryngopharyngeal reflux and identifies areas of controversy and future opportunities for research.

RECENT FINDINGS

Despite numerous research efforts, the diagnosis and treatment of laryngopharyngeal reflux remain elusive and unproven. Acid-induced changes in laryngopharyngeal mucosa have been confirmed by histologic evidence. However, the implications of this for laryngeal symptoms and signs are unclear. Diagnosis remains controversial, confounded by lack of standardization and accepted, evidence-based norms. Whereas treatment is generally believed by clinicians to be effective in alleviating symptoms and signs attributed to laryngopharyngeal reflux, incontrovertible data confirming efficacy are scarce. Confounding the issues further, there are numerous studies that purport to show that various widely used treatments are not effective, although the scientific merit of virtually all of these studies has been challenged.

SUMMARY

Laryngopharyngeal reflux remains a controversial diagnosis. Treatment with proton pump inhibitors persists despite weak evidence supporting or refuting their utility, and well designed studies are needed to understand diagnosis, treatment, pathyophysiology, and long-term health consequences of laryngopharyngeal reflux and its treatment.

The diagnosis and management of globus: a perspective from Japan

PURPOSE OF REVIEW

The etiology of globus is multifactorial and its management is controversial. Recent findings in the etiology and diagnosis of globus are discussed, and a subjective opinion on its management is presented.

RECENT FINDINGS

Although there is considerable debate concerning the role of gastroesophageal reflux disease (GERD) in patients with globus, the globus symptom score has been shown to be significantly higher in patients with GERD than in those without GERD. This definite association between GERD and globus leads to the practical division of patients with globus into two groups: the GERD/laryngopharyngeal reflux (LPR)-induced and non-GERD/LPR groups. When the presence of GERD or LPR or both is established in patients with globus, management of this condition should be considered. Owing to limitations in the technology for the detection of GERD/LPR, precise discrimination between the two groups is still difficult. For practical purposes, empirical approaches for targeting GERD in patients with globus appear to be justified. A 24 h pH-metry/multichannel intraluminal impedance test may increase the detection of reflux events in patients with globus.

SUMMARY

A practical approach for dividing patients with globus into GERD/LPR-induced and non-GERD/LPR groups is introduced.

Cornulin, a marker of late epidermal differentiation, is down-regulated in eczema

BACKGROUND

Eczema is a common chronic inflammatory skin disorder which shows strong genetic predisposition. To identify new potential molecular determinants of the disease pathogenesis, we performed a gene expression study in an eczema mouse model. This analysis identified a marked down regulation of the cornulin gene (CRNN), a member of the epidermal differentiation complex, in the eczema-like skin. We then investigated CRNN as an eczema candidate gene and studied its polymorphism and the expression in the skin of eczema patients.

METHODS

An eczema-like phenotype was induced in mice by allergen (Der p2) patching. Gene expression analysis was performed with the subtractive suppression hybridization method and validated by real time PCR and the transmission disequilibrium test was used to test for genetic associations in 406 multiplex eczema families.

RESULTS

Der p 2 patched mice developed a localized eczema and a Th 2 skewed systemic response. Real time PCR analysis confirmed a down regulation of CRNN mRNA in eczema-like skin in the mouse model and in human eczema. The CRNN polymorphism rs941934 was significantly associated with atopic eczema in the genetic analysis (P = 0.006), though only as part of an extended haplotype including a known associated variant (2282del4) in the filaggrin gene.

CONCLUSIONS

CRNN mRNA expression is decreased in eczematous skin. Further studies are needed to verify whether the associated cornulin polymorphism contribute to the genetic susceptibility in eczema.

Activity/Stability of Human Pepsin: Implications for Reflux Attributed Laryngeal Disease

OBJECTIVES/HYPOTHESIS

Exposure of laryngeal epithelia to pepsin during extra-esophageal reflux causes depletion of laryngeal protective proteins, carbonic anhydrase isoenzyme III (CAIII), and squamous epithelial stress protein Sep70. The first objective of this study was to determine whether pepsin has to be enzymatically active to deplete these proteins. The second objective was to investigate the effect of pH on the activity and stability of human pepsin 3b under conditions that might be found in the human esophagus and larynx.

STUDY DESIGN

Prospective translational research study.

METHODS

An established porcine in vitro model was used to examine the effect of active/inactive pepsin on laryngeal CAIII and Sep70 protein levels. The activity and stability of pepsin was determined by kinetic assay, measuring the rate of hydrolysis of a synthetic pepsin-specific substrate after incubation at various pH values for increasing duration.

RESULTS

Active pepsin is required to deplete laryngeal CAIII and Sep70. Pepsin has maximum activity at pH 2.0 and is inactive at pH 6.5 or higher. Although pepsin is inactive at pH 6.5 and above, it remains stable until pH 8.0 and can be reactivated when the pH is reduced. Pepsin is stable for at least 24 hours at pH 7.0, 37 degrees C and retains 79% +/- 11% of its original activity after re-acidification at pH 3.0.

CONCLUSIONS

Detectable levels of pepsin remain in laryngeal epithelia after a reflux event. Pepsin bound there would be enzymatically inactive because the mean pH of the laryngopharynx is pH 6.8. Significantly, pepsin could remain in a form that would be reactivated by a subsequent decrease in pH, such as would occur during an acidic reflux event or possibly after uptake into intracellular compartments of lower pH.

Gastric pepsin in middle ear fluid of children with otitis media: clinical implications

Gastroesophageal reflux and extraesophageal reflux have been postulated to be involved in the pathogenesis of otitis media. This is supported by recent studies revealing the presence of gastric pepsin in the middle ear space of children with otitis media but not in control patients without otitis media. Reflux's role in otitis media appears to be most pronounced in younger children and those with purulent effusions.

Immunologic Response of the Laryngeal Mucosa to Extraesophageal Reflux

Objectives:

Extraesophageal reflux is common. The treatment costs are high, and there are associations with other diseases, including laryngeal cancer. Our studies of the mucosal immune response to this common inflammatory disease suggest an important role for the nonclassic antigen-presenting molecule CD1d in the response to inflammation. This study was performed to further explore the relationship between the CD1d–NKT cell–iGb3 axis and reflux.

Methods:

We carried out a prospective study of laryngeal biopsies from 12 patients with laryngopharyngeal reflux and 11 controls. Quantitative multiple-color immunofluorescence using antibodies for lymphocytes (CD3, CD161) and classic and nonclassic major histocompatibility complex (I, II, β2m, CD1d) was performed, and univariate and multivariate analysis and co-localization measurements were applied.

Results:

Epithelial major histocompatibility complex class I and II expression was unchanged by reflux, but expression of CD1d increased (p < 0.05; luminal layers) and confidence intervals diminished in the reflux group. Co-localization of NKT cells with CD1d increased in patients (p < 0.01); iGb3 exhibited strong expression throughout all layers of the laryngeal epithelium.

Conclusions:

These data indicate a role for the CD1d–NKT cell–iGb3 axis in response to extraesophageal reflux in humans. This represents a useful target for novel diagnostics and treatments for this common condition.

Otolaryngological perspective on patients with throat symptoms and laryngeal irritation

The diagnosis of laryngopharyngeal reflux (LPR) is increasingly common in otolaryngology practice. Patients with nonspecific throat and voice symptoms, such as throat clearing, hoarseness, cough, sore throat, and globus, are frequently treated empirically with antireflux medication by otolaryngologists and primary care physicians. Physical findings such as laryngeal erythema, edema, and posterior laryngeal mucosal thickening are also frequently attributed to LPR. The literature has been inconsistent, with few prospective, randomized trials showing efficacy for this clinical practice. Because of the lack of specific signs and symptoms of LPR, clinicians should be aware of other potential causes for these clinical presentations. Recently published studies describe the association between allergy or asthma and many of the same symptoms attributed to reflux disease. Muscle tension dysphonia can also present with hoarseness and symptoms of throat irritation. Although LPR can cause the symptoms and signs described previously, it should not be the only diagnosis considered by the evaluating physician. Failure to consider other possible causes may result in unnecessary treatment and potential delay in diagnosis. This article discusses this topic, citing some of the pertinent literature published over the past 2 years.

Mucin Gene Expression in Human Laryngeal Epithelia: Effect of Laryngopharyngeal Reflux

Objectives:

We sought to document the mucin gene profile in normal human laryngeal epithelium and compare it with that in patients with reflux-attributed laryngeal injury or disease. We also investigated the effect of low pH with or without pepsin on mucin messenger RNA levels in vitro.

Methods:

Laryngeal biopsy specimens were obtained from 3 patients with clinically diagnosed laryngopharyngeal reflux and from 2 control subjects who had no signs or symptoms of reflux. Signs and symptoms were assessed by the Reflux Finding Score and the Reflux Symptom Index, respectively. Reverse transcription–polymerase chain reaction (RT-PCR) was performed to establish the mucin gene profile. Human hypopharyngeal epithelial cells were exposed to pH 7, 5, 4, and 2 with and without pepsin (0.1 mg/mL) for 20 minutes at 37°C, and expression of selected mucins was analyzed via real-time RT-PCR.

Results:

Mucin 1–5, 7, 9, 13, 15, 16, and 18–20 transcripts were detected in normal laryngeal epithelium, whereas mucin 6, 8, and 17 transcripts were not. Mucins 2, 3, and 5 were expressed at reduced levels in patients with reflux-attributed laryngeal injury or disease. These mucin genes were up-regulated after exposure to low pH in vitro (p < 0.005). Pepsin inhibited this up-regulation (p < 0.001).

Conclusions:

Reflux laryngitis is associated with down-regulation of mucin gene expression.

The role of extraesophageal reflux in otitis media in infants and children

OBJECTIVES/HYPOTHESIS

Gastroesophageal reflux disease (GERD) is common in children, and extraesophageal reflux disease (EORD) has been implicated in the pathophysiology of otitis media (OM). We sought to 1) determine the incidence of pepsin/pepsinogen presence in the middle ear cleft of a large sample of pediatric patients undergoing myringotomy with tube placement for OM; 2) compare this with a control population of pediatric patients undergoing middle ear surgery (cochlear implantation) with no documented history of OM; 3) analyze potential risk factors for OM in children with EORD demonstrated by the presence of pepsin in the middle ear cleft; and 4) determine if pepsin positivity at the time of myringotomy with tube placement predisposes to posttympanostomy tube otorrhea.

STUDY DESIGN AND METHODS

STUDY GROUP

prospective samples of 509 pediatric patients (n = 893 ear samples) undergoing myringotomy with tube placement for recurrent acute OM and/or otitis media with effusion in a tertiary care pediatric hospital with longitudinal follow-up of posttympanostomy tube otorrhea.

CONTROL GROUP

prospective samples of 64 pediatric patients (n = 74 ears) with negative history of OM undergoing cochlear implantation at one of the three tertiary care pediatric hospitals. A previously validated, highly sensitive and specific modified enzymatic assay was used to detect the presence of pepsin in the middle ear aspirates of study and control patients. Risk factors for OM and potentially associated conditions, including GERD, allergy, and asthma were analyzed for the study group through review of the electronic medical record and correlated topresence of pepsin in the middle ear space. Study patients were followed longitudinally postoperatively to determine the incidence of posttympanostomy tube otorrhea.

RESULTS

The incidence of pepsin in the middle ear cleft of the study group was 20% of patients and 14% of ears, which is significantly higher than 1.4% of control patients and 1.5% of control ears (P < .05). Study patients younger than 1 year had a higher rate of purulent effusions and pepsin in the middle ear cleft (P < .05). Patients with pepsin in the middle ear cleft were more likely to have an effusion at the time of surgery than patients without pepsin in the middle ear cleft (P < .05). There was no statistical association found between the presence of pepsin and clinical history of GERD, allergy, asthma, or posttympanostomy tube otorrhea.

CONCLUSIONS

Pepsin is detectable in the middle ear cleft of 20% of pediatric patients with OM undergoing tympanostomy tube placement, compared with 1.4% of controls; recovery of pepsin in the middle ear space of pediatric patients with OM is an independent risk factor for OM. Patients under 1 year of age have a higher incidence of purulent effusions and pepsin-positive effusions. Clinical history of GERD, allergy, and asthma do not seem to correlate with evidence of EORD reaching the middle ear cleft. The presence of pepsin in the middle ear space at the time of tube placement does not seem to predispose to posttympanostomy tube otorrhea.

The mucosal immune response to laryngopharyngeal reflux

RATIONALE

Laryngopharyngeal reflux (LPR) affects up to 20% of Western populations. Although individual morbidity is usually moderate, treatment costs are high and there are associations with other diseases, including laryngeal cancer. To date, there have been no studies of the mucosal immune response to this common inflammatory disease.

OBJECTIVES

To determine the mucosal immune response to LPR.

METHODS

We performed a prospective immunologic study of laryngeal biopsies from patients with LPR and control subjects (n = 12 and 11, respectively), and of primary laryngeal epithelial cells in vitro.

MEASUREMENTS AND MAIN RESULTS

Quantitative multiple-color immunofluorescence, using antibodies for lymphocytes (CD4, CD8, CD3, CD79, CD161), granulocytes (CD68, EMBP), monocytic cells (CD68, major histocompatibility complex [MHC] class II), and classical and nonclassical MHC (I, II, beta(2)-microglobulin, CD1d). Univariate and multivariate analysis and colocalization measurements were applied. There was an increase in percentage area of mucosal CD8(+) cells in the epithelium (P < 0.005), whereas other leukocyte and granulocyte antigens were unchanged. Although epithelial MHC class I and II expression was unchanged by reflux, expression of the nonclassical MHC molecule CD1d increased (P < 0.05, luminal layers). In vitro, laryngeal epithelial cells constitutively expressed CD1d. CD1d and MHC I expression were inversely related in all subjects, in a pattern which appears to be unique to the upper airway. Colocalization of natural killer T (NKT) cells with CD1d increased in patients (P < 0.01).

CONCLUSIONS

These data indicate a role for the CD1d-NKT cell axis in response to LPR in humans. This represents a useful target for novel diagnostics and treatments in this common condition.

Receptor-mediated uptake of pepsin by laryngeal epithelial cells

OBJECTIVES

Previous data suggest a mechanistic link between exposure to pepsin and cellular changes that lead to laryngopharyngeal disorders. Initial confocal microscopy analysis of pepsin uptake by cultured hypopharyngeal epithelial cells revealed that pepsin may be taken up by a specific process. The objective of this study was to use electron microscopy to confirm the initial confocal findings and to determine whether uptake of pepsin by laryngeal epithelial cells is receptor-mediated.

METHODS

Cultured human hypopharyngeal FaDu cells and human laryngeal biopsy specimens, taken from the posterior larynx of "control" patients without symptoms or findings of laryngopharyngeal reflux, were exposed to purified human pepsin 3b with or without transferrin (a marker for receptor-mediated endocytosis) in vitro. Uptake of pepsin was documented by electron microscopy.

RESULTS

Pepsin co-localized with transferrin in intracellular vesicles; this finding confirms that pepsin is taken up by laryngeal epithelial cells by receptor-mediated endocytosis.

CONCLUSIONS

This is a novel finding that further defines the role and mechanism of pepsin-mediated injury in laryngopharyngeal reflux. The objective of ongoing research is to identify the receptor and investigate potential antagonists as a new therapeutic option for patients with reflux-attributed disease--in particular, those patients who have persistent symptoms despite acid suppression therapy.

Review article: The laryngological manifestations of reflux disease; why the scepticism?

BACKGROUND

Despite increasing clinical and experimental evidence of its existence, otolaryngological manifestations of reflux disease remain controversial, concerning diagnosis as well as treatment.

AIM

Proper understanding of laryngopharyngeal reflux disease (LPRD).

METHOD

Review of literature.

RESULTS

Scepticism concerning LPRD is based upon differences between gastro-oesophageal reflux disease and LPRD; lack of specificity and sensitivity of diagnostic tests to confirm LPRD; non-specificity of laryngological symptoms, which are difficult to distinguish from other causes of upper respiratory tract inflammation; non-specificity of laryngological signs in laryngoscopy, with high intra- and inter-observer variability in evaluation; diagnosis of LPRD is essentially only based on a combination of diagnostic signs and symptoms, which cannot be attributed to other pathology; slow, or sometimes lack of, response of LPRD symptoms to proton pump inhibitor (PPI) medication and lack of evidence concerning efficacy of PPIs in placebo-controlled trials.

CONCLUSIONS

LPRD remains a diagnosis by exclusion and resolution of symptoms following 4-month trial of 40 mg PPI twice daily is, for all practical purposes, considered proof of the initial diagnosis. However, non-response does not exclude LPRD as PPIs have no influence on noxious non-acid components of the refluxate.

Prevalence of laryngopharyngeal reflux in a population with gastroesophageal reflux

OBJECTIVE

Laryngopharyngeal reflux (LPR) is a syndrome associated with a constellation of symptoms usually treated by ENT surgeons. It is believed to be caused by the retrograde flow of stomach contents into the laryngopharynx, this being a supra-esophageal manifestation of gastroesophageal reflux disease (GERD). It has been cited that LPR and GERD can be considered separate entities. Our hypothesis was that LPR is a supra-esophageal manifestation of GERD and therefore that patients with GERD should have a degree of symptoms suggestive of LPR because of the reflux of the gastric contents. We examined a population of patients with both upper gastrointestinal endoscopy and symptom-proven GERD and, using a questionnaire, looked at their existing symptoms to help assess the prevalence of LPR. We also looked at whether, with more severe GERD (suggestive of increased gastric content reflux), the degree of symptoms suggestive of LPR would be increased, as would be expected.

METHODS

A population of patients with endoscopically proven GERD were recruited and divided into groups depending on the severity of their reflux disease. A questionnaire was then administered that examined both LPR and GERD scoring criteria. The relationship between GERD and LPR was then analyzed.

RESULTS

We recruited 1,383 subjects with GERD; those with severe GERD had significantly higher LPR scores compared with those with mild (P < .01), moderate (P < .05), or inactive disease (P < .001).

CONCLUSIONS

The condition of LPR is likely to represent a supra-esophageal manifestation of GERD. This study examined a large number of patients with endoscopically proven GERD and has demonstrated a correlation between the severity of GERD and the prevalence of LPR. LPR and GERD are common and interlinked conditions. The subsequent prevalence of LPR in the population with GERD is therefore likely to be dramatically underestimated.

Impact of different pH thresholds for 24-hour dual probe pH monitoring in patients with suspected laryngopharyngeal reflux

OBJECTIVES

The gold standard test for laryngopharyngeal reflux is 24-hour pH monitoring, which determines the reflux area index with a pH threshold of less than four (i.e. the reflux area index four). However, refluxed pepsin is able to cause laryngeal injury at pH levels above five.

STUDY DESIGN

Prospective study.

MATERIALS AND METHODS

In order to establish normative values for a reflux area index with a pH threshold of less than five (i.e. the reflux area index five), 29 healthy volunteers underwent pH monitoring. In 45 patients with suspected laryngopharyngeal reflux, reflux area index four and reflux area index five were determined by pH study.

RESULTS

In healthy volunteers, the reflux area index five was 72.6 (95th percentile). In 29 of 44 patients, laryngopharyngeal reflux was diagnosed due to a reflux area index four of greater than 6.3. However, the reflux area index five revealed laryngopharyngeal reflux in six more patients.

CONCLUSIONS

For exact analysis of pH monitoring results, two pH thresholds (less than four and less than five) must be considered. Further studies with a larger number of healthy volunteers are necessary in order to reveal normative values for the reflux area index five parameter.

Extraesophageal reflux in children

PURPOSE OF REVIEW

To summarize and contextualize current concepts in the incidence, diagnosis, management and long-term sequelae of extraesophageal reflux disease in children.

RECENT FINDINGS

Extraesophageal reflux disease is a different disease entity from gastroesophageal reflux disease. The two diseases have a common etiology, refluxate causing mucosal damage, but the extent and location of the damage varies considerably depending on the underlying mucosal characteristics. Extraesophageal reflux disease in children is characterized by a broad set of symptoms and signs that vary according to age at presentation and severity of disease. Serious long-term effects begin in childhood. The role of pepsin, bile acids, pancreatic enzymes, motility disorders, and food allergies have only recently been recognized. Newer diagnostic modalities include multichannel intraluminal pH/impedance, the 48 h Bravo implantable probe, and hypopharyngeal pH monitoring. While proton pump inhibitors provide superior acid suppression compared with histamine-2 blockers, variability in response and lack of efficacy for alkaline refluxate often require other therapeutic interventions.

SUMMARY

Pediatric extraesophageal reflux disease has variable presentation and a gold standard test is still lacking. Primary treatment includes lifestyle and feeding changes and medical therapy. Ongoing monitoring for recurrence and agreement as to duration of therapy present significant challenges not yet standardized amongst practitioners.

Relationship between time of exposure of laryngopharyngeal reflux and gene expression in laryngeal fibroblasts

OBJECTIVES

Acid reflux is damaging to the laryngeal mucosa; however, the significance of the duration of reflux episodes has not been evaluated. The purpose of this study was to determine whether varying the exposure times at low pH with or without pepsin alters gene expression in laryngeal fibroblasts.

METHODS

Human false vocal fold and postcricoidal cultures were exposed to pH 4 or pH 5 media with and without pepsin for 10, 30, 60, and 240 seconds. Using a real-time polymerase chain reaction, we determined the messenger RNA expression of TGFbeta-1, VEGF, FGF-2, EGR-1, ATF-3, CTGF, MMP-1, MMP-2, and decorin.

RESULTS

Molecular responses were initiated at pH 5. Postcricoidal fibroblasts were more sensitive than false vocal fold fibroblasts to the presence of pepsin. Changes in transcript levels were dependent on acid exposure time, and the most significant changes were measured during the first 60 seconds after exposure.

CONCLUSIONS

Time of exposure to acid and pepsin needs to be taken into consideration when determining limit of pathology in pharyngeal reflux. Genes are identified that are induced by low pH and that may be of potential importance in the pathogenesis of reflux laryngitis.

Review article: human pepsins - their multiplicity, function and role in reflux disease

Human gastric juice contains a multiplicity of proteinases. These are classified as aspartic proteinases because of enzymic activity dependent on two oppositely placed aspartic acids in the active site region. At least seven zones of activity can be visualized by agar gel electrophoresis and a similar number of separate proteins resolved by high performance ion exchange chromatography. The major enzyme secreted (up to 70% of the total) pepsin 3b is sensitive to the selective inhibitor pepstatin whereas gastricsin or pepsin 5 (20% of the total) is not. Minor enzymes including pepsin 1, which has an associated proteincarbohydrate complex attached is variable and can be < 5% in normal and up to 20% of the total as in peptic ulcer patients. The activity of these enzymes depends on the substrate and pH with significant digestion occurring up to pH 4.5. It has also been shown that these enzymes can bind to substrates like collagen up to pH 5.5. In gastric secretion studies of patients with reflux oesophagitis the amount of pepsin and the profile of the enzymes in basal secretions, and that after pentagastrin stimulation, was found to be not different from healthy non-refluxers. Thus the problem with reflux is that gastric juice appears in the oesophagus, an area without any natural protection from proteolytic damage. The ability to reduce gastric secretion is therefore important in effective treatment. However, being able also to inhibit enzymic activity or protect substrates from damage using alginates offers considerable scope for future therapies.

Review article: the role of bile and pepsin in the pathophysiology and treatment of gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease is a multifaceted and multifactorial disorder which results from the reflux of gastric contents into the oesophagus. Animal studies suggest that synergism between acid and pepsin and conjugated bile acids have the greatest damaging potential for oesophageal mucosa, although unconjugated bile acids may be caustic at more neutral pH. Human studies are compatible with a synergistic action between acid and duodenogastric reflux in inducing lesions. During prolonged monitoring studies, typical gastro-oesophageal reflux symptoms are more related to acid reflux events than to non-acid reflux events. However, symptoms that persist during acid suppressive therapy are often related to non-acid reflux events. The therapeutic options for the non-acid component of the refluxate, including acid suppression, prokinetics, baclofen, surgery and mucosal protective agents like alginates, are discussed.