Pepsin, a biomarker of gastric aspiration in lung allografts: a putative association with rejection

The foregut in cystic fibrosis

The aerodigestive organs share a kindred embryologic origin that allows for a more complete explanation as to how the foregut can remain a barrier to normalcy in people with cystic fibrosis (pwCF). The structures of the aerodigestive tract include the nasopharynx, the oropharynx, the hypopharynx, the esophagus, the stomach, as well as the supraglottic, glottic, and subglottic tubular airways (including the trachea). Additional gastrointestinal (GI) luminal/alimentary organs of the foregut include the duodenum. Extraluminal foregut structures include the liver, the gall bladder, the biliary tree, and the pancreas. There are a variety of neurologic controls within these complicated anatomic compartments to separate the transit of food and liquid from air. These structures share the same origin from the primitive foregut/mesenchyme. The vagus nerve is a critical structure that unites respiratory and digestive functions. This article comments on the interconnected nature of cystic fibrosis and the GI tract. As it relates to the foregut, this has been typically treated as simple "reflux" as the cause of worsened lung function in pwCF. That terms like gastroesophageal reflux (GER), gastroesophageal reflux disease (GERD), heartburn, and regurgitation are used interchangeably to reflect pathology further complicates matters; we offer a more physiologically accurate term called "GI-related aspiration" or "GRASP." Broadly, this term reflects that aspiration of foregut contents from the duodenum through the stomach to the esophagus, into the pharynx and the respiratory tree in pwCF. As a barrier to normalcy in pwCF, GRASP is fundamentally two disease processes-GERD and gastroparesis-that likely contribute most to the deterioration of lung disease in pwCF. In the modulator era, successful GRASP management will be critical, particularly in those post-lung transplantation (LTx), only through successful management of both GERD and gastroparesis. Standardization of clinical management algorithms for GRASP in CF-related GRASP is a key clinical and research gap preventing normalcy in pwCF; what exists nearly exclusively addresses surgical evaluations or offers guidance for the management of GI symptoms alone (with unclear parameters for respiratory disease considerations). We begin first by describing the result of GRASP damage to the lung in various stages of lung disease. This is followed by a discussion of the mechanisms by which the digestive tract can injure the lungs. We summarize what we anticipate future research directions will be to reduce the impact of GRASP as a barrier to normalcy in pwCF.

Concurrent abnormal non-acid reflux is associated with additional chronic rejection risk in lung transplant patients with increased acid exposure

Acid reflux has been associated with allograft injury and rejection in lung transplant patients; however, the pathogenic role of non-acid reflux remains debated. We aimed to evaluate the impact of concurrent abnormal non-acid reflux with acid reflux on chronic rejection in lung transplant patients with acid reflux. This was a retrospective cohort study of lung transplant recipients who underwent pre-transplant combined impedance-pH study off acid suppression. Only subjects with acid exposure >4% were included. Non-acid reflux (pH > 4) episodes >27 was considered abnormal per prior normative studies. Chronic rejection was defined as chronic lung allograft dysfunction (CLAD) per International Society for Heart and Lung Transplantation criteria. Time-to-event analyses were performed using Cox proportional hazards and Kaplan-Maier methods, with censoring at death, anti-reflux surgery, or last follow-up. In total, 68 subjects (28 abnormal/40 normal non-acid reflux) met inclusion criteria for the study. Baseline demographic/clinical characteristics were similar between groups. Among this cohort of patients with increased acid exposure, subjects with concurrent abnormal non-acid reflux had significantly higher risk of CLAD than those without on Kaplan-Meier analysis (log-ranked P = 0.0269). On Cox multivariable regression analysis controlling for body mass index, age at transplantation, and proton pump inhibitor use, concurrent abnormal non-acid reflux remained independently predictive of increased CLAD risk (hazard ratio 2.31, confidence interval: 1.03-5.19, P = 0.04). Presence of concurrent abnormal non-acid reflux in lung transplant subjects with increased acid exposure is associated with additional risk of chronic rejection. Non-acid reflux may also contribute to pathogenicity in lung allograft injury/rejection, supporting a potential role for impedance-based testing in this population.

Airway pepsinogen A4 identifies lung transplant recipients with microaspiration and predicts chronic lung allograft dysfunction

BACKGROUND

Aspiration is a known risk factor for adverse outcomes post-lung transplantation. Airway bile acids are the gold-standard biomarker of aspiration; however, they are released into the duodenum and likely reflect concurrent gastrointestinal dysmotility. Previous studies investigating total airway pepsin have found conflicting results on its relationship with adverse outcomes post-lung transplantation. These studies measured total pepsin and pepsinogen in the airways. Certain pepsinogens are constitutively expressed in the lungs, while others, such as pepsinogen A4 (PGA4), are not. We sought to evaluate the utility of measuring airway PGA4 as a biomarker of aspiration and predictor of adverse outcomes in lung transplant recipients (LTRs) early post-transplant.

METHODS

Expression of PGA4 was compared to other pepsinogens in lung tissue. Total pepsin and PGA4 were measured in large airway bronchial washings and compared to preexisting markers of aspiration. Two independent cohorts of LTRs were used to assess the relationship between airway PGA4 and chronic lung allograft dysfunction (CLAD). Changes to airway PGA4 after antireflux surgery were assessed in a third cohort of LTRs.

RESULTS

PGA4 was expressed in healthy human stomach but not lung. Airway PGA4, but not total pepsin, was associated with aspiration. Airway PGA4 was associated with an increased risk of CLAD in two independent cohorts of LTRs. Antireflux surgery was associated with reduced airway PGA4.

CONCLUSIONS

Airway PGA4 is a marker of aspiration that predicts CLAD in LTRs. Measuring PGA4 at surveillance bronchoscopies can help triage high-risk LTRs for anti-reflux surgery.

Impact of gastro-jejunostomy tube in lung transplant patients: a propensity-matched analysis

OBJECTIVES

During the postoperative phase of lung transplantation, the surgical creation of a gastro-jejunostomy (GJ) may be deemed necessary for patients with severe oesophageal dysmotility, prolonged oral intake difficulties stemming from use of a ventilator or marked malnutrition. We explored the effects of postoperative GJ tube on survival and bronchiolitis obliterans syndrome in lung transplant recipients.

METHODS

We retrospectively reviewed all lung transplants performed at our institution between 2011 and 2022. Propensity score matching was performed to match patients who required a GJ tube with control patients on a 1:1 ratio. The preoperative, operative and postoperative outcomes of the patients were evaluated.

RESULTS

After propensity score matching, 193 patients with GJ were compared to 193 patients without GJ. Patients with GJ had significantly higher rates of delayed chest closure (P = 0.007), and postoperative dialysis (P = 0.016), longer intensive care unit stays (P < 0.001), longer ventilator duration (P < 0.001), higher rates of pneumonia (P = 0.035) and higher rates of being treated for acute cellular rejection within 1 year of transplant (P = 0.008). Overall survival and freedom from bronchiolitis obliterans syndrome were not found to be significantly different between the matched groups (P = 0.09 and P = 0.3).

CONCLUSIONS

GJ tube placement during the postoperative phase of lung transplantation did not compromise patient survival or freedom from bronchiolitis obliterans syndrome although the results reflect more difficult and complicated cases. This study indicates that the GJ tube may be a useful option for enteral feeding.

Evaluation of Donor Lungs for Transplantation: The Efficacy of Screening Bronchoscopy for Detecting Donor Aspiration and Its Relationship to the Resulting Allograft Function in Corresponding Recipients

BACKGROUND

Potential organ donors often have suffered anoxic and/or traumatic brain injury during which they may have experienced aspiration of gastric material (AGM). Evaluation of such donors typically includes a screening bronchoscopic examination during which determinations of aspiration are made. The efficacy of this visual screening and its relationship to post-transplant allograft function are unknown.

METHODS

Before procurement, bronchoscopy was performed on donors in which both bronchoalveolar lavage fluid (BALF) was collected and a visual inspection made. As a marker of AGM, BALF specimens were analyzed for the presence of bile salts. Data collected on the corresponding recipients included primary graft dysfunction (PGD) score, post-transplant spirometry, acute rejection scores (ARS), and overall survival.

RESULTS

Of 31 donors evaluated, bronchoscopies revealed only 2 with visual evidence of AGM, whereas BALF analysis for bile salts indicated AGM in 14. As such, screening bronchoscopy had a sensitivity of only 7.1%. Visual detection of AGM via bronchoscopy was not associated with any resulting grade of PGD (χ2 = 2.96, P = .23); however, AGM defined by detection of bile salts was associated (χ2 = 7.56, P = .02). Over the first post-transplant year, the corresponding recipients experienced a similar improvement in allograft function (χ2 = 1.63, P = .69), ARS (P = .69), and survival (P = .24).

CONCLUSION

Visual inspection during a single bronchoscopic examination of lung donors underestimates the prevalence of AGM. The detection of bile salts in donor BALF is associated with early allograft dysfunction in the corresponding recipients but not with later allograft proficiency, acute rejection responses, or 1-year post-transplant survival.

Oesophageal stasis is a risk factor for chronic lung allograft dysfunction and allograft failure in lung transplant recipients

Background

Morbidity and mortality in lung transplant recipients are often triggered by recurrent aspiration events, potentiated by oesophageal and gastric disorders. Previous small studies have shown conflicting associations between oesophageal function and the development of chronic lung allograft dysfunction (CLAD). Herein, we sought to investigate the relationship between oesophageal motility disorders and long-term outcomes in a large retrospective cohort of lung transplant recipients.

Methods

All lung transplant recipients at the Toronto Lung Transplant Program from 2012 to 2018 with available oesophageal manometry testing within the first 7 months post-transplant were included in this study. Patients were categorised according to the Chicago Classification of oesophageal disorders (v3.0). Associations between oesophageal motility disorders with the development of CLAD and allograft failure (defined as death or re-transplantation) were assessed.

Results

Of 487 patients, 57 (12%) had oesophagogastric junction outflow obstruction (OGJOO) and 47 (10%) had a disorder of peristalsis (eight major, 39 minor). In a multivariable analysis, OGJOO was associated with an increased risk of CLAD (HR 1.71, 95% CI 1.15-2.55, p=0.008) and allograft failure (HR 1.69, 95% CI 1.13-2.53, p=0.01). Major disorders of peristalsis were associated with an increased risk of CLAD (HR 1.55, 95% CI 1.01-2.37, p=0.04) and allograft failure (HR 3.33, 95% CI 1.53-7.25, p=0.002). Minor disorders of peristalsis were not significantly associated with CLAD or allograft failure.

Conclusion

Lung transplant recipients with oesophageal stasis characterised by OGJOO or major disorders of peristalsis were at an increased risk of adverse long-term outcomes. These findings will help with risk stratification of lung transplant recipients and personalisation of treatment for aspiration prevention.

Tolerability and Feasibility of the Upper Esophageal Sphincter Assist Device in Preventing Acute and Chronic Allograft Rejection Among Lung Transplant Recipients

GOALS

We aimed to evaluate a novel upper esophageal sphincter (UES) assist device loaner program for the prevention of acute cellular rejection and chronic lung allograft dysfunction among lung transplant (LTx) recipients.

BACKGROUND

Laryngopharyngeal reflux can lead to chronic microaspiration and LTx rejection. The UES assist device applies external pressure at the level of UES to decrease reflux.

STUDY

We prospectively enrolled and issued UES assist devices to consecutive transplant patients referred for gastrointestinal motility testing from 2016 to 2020. Device tolerability was defined by successful utilization as a bridge to ambulatory pH monitoring and/or antireflux procedure, or as permanent therapy. Incidence of rejection was analyzed before, during, and after device implementation.

RESULTS

Twenty-six participants were issued devices (15 pathologic, 5 physiological, 6 unknown reflux status), none of whom developed acute rejection episodes or chronic lung allograft dysfunction while using the device. Thirteen adopted the device promptly after transplantation (mean 1.7 mo) and remained free of rejection episodes over a mean 24.7 months of follow-up. Among those with pathologic reflux, lag time to device adoption strongly correlated with the development of rejection ( r =0.8, P =0.0006). There was no such correlation among those with physiological reflux. Five developed acute rejection after device return.

CONCLUSIONS

The device was tolerated by a majority of LTx patients and appears feasible as a barrier measure in the prevention of rejection. Delayed treatment of laryngopharyngeal reflux may lead to early allograft failure; therefore, the UES assist device should be given important consideration in transplant protection.

Reflux Surgery in Lung Transplantation: A Multicenter Retrospective Study

BACKGROUND

Aspiration has been associated with graft dysfunction after lung transplantation, leading some to advocate for selective use of fundoplication despite minimal data supporting this practice.

METHODS

We performed a multicenter retrospective study at 4 academic lung transplant centers to determine the association of gastroesophageal reflux disease and fundoplication with bronchiolitis obliterans syndrome and survival using Cox multivariable regression.

RESULTS

Of 542 patients, 136 (25.1%) underwent fundoplication; 99 (18%) were found to have reflux disease without undergoing fundoplication. Blanking the first year after transplantation, fundoplication was not associated with a benefit regarding freedom from bronchiolitis obliterans syndrome (hazard ratio [HR], 0.93; 95% CI, 0.58-1.49) or death (HR, 0.97; 95% CI, 0.47-1.99) compared with reflux disease without fundoplication. However, a time-dependent adjusted analysis found a slight decrease in mortality (HR, 0.59; 95% CI, 0.28-1.23; P = .157), bronchiolitis obliterans syndrome (HR, 0.68; 95% CI, 0.42-1.11; P = .126), and combined bronchiolitis obliterans syndrome or death (HR, 0.66; 95% CI, 0.42-1.04; P = .073) in the fundoplication group compared with the gastroesophageal reflux disease group.

CONCLUSIONS

Although a statistically significant benefit from fundoplication was not determined because of limited sample size, follow-up, and potential for selection bias, a randomized, prospective study is still warranted.

Association Between Antibodies Against Lung Self-Antigens and Gastroesophageal Reflux in Lung Transplant Candidates

Gastroesophageal reflux (GER) and pretransplant antibodies against lung self-antigens (SAbs) collagen-V and/or k-alpha 1 tubulin are both independently associated with allograft dysfunction after lung transplantation (LTx). The role of GER in inducing lung injury and SAbs is unknown. We aimed to study the association between pre-LTx GER and SAbs. After IRB approval, we retrieved SAb assays conducted between 2015 and 2019 and collected 24 hour GER data for these patients. Patients were divided into 2 groups: no reflux (GER-) and pathologic reflux (GER+) to compare the prevalence of SAbs. Multivariate analysis was used to study the association between GER and SAbs in the whole cohort and in restrictive lung disease (RLD) and obstructive lung disease (OLD) subsets. Proximal esophageal reflux (PER) events ≥5 was considered abnormal. Patients (n = 134; 73 men) were divided into groups: GER- (54.5%, n = 73) and GER+ (45.5%, n = 61). The prevalence of GER was higher in the RLD than in the OLD subset (p < 0.001). The overall prevalence of SAbs was 53.7% (n = 72), higher in the GER+ than the GER- group (65.6% vs 43.8%, p = 0.012), but comparable between RLD and OLD subsets. Overall, SAbs were associated with GER (p = 0.012) and abnormal PER (p = 0.017). GER and abnormal PER increased the odds of SAbs in the RLD subset (OR [95% CI]: 2.825 [1.033-7.725], p = 0.040 and OR [95% CI]: 3.551 [1.271-9.925], p = 0.014, respectively) but not in the OLD subset. LTx candidates have a high prevalence of SAbs, which are significantly associated with GER and abnormal PER in patients with RLD.

Utility of bile acids in large airway bronchial wash versus bronchoalveolar lavage as biomarkers of microaspiration in lung transplant recipients: a retrospective cohort study

Background

Bronchoalveolar lavage (BAL) is a key tool in respiratory medicine for sampling the distal airways. BAL bile acids are putative biomarkers of pulmonary microaspiration, which is associated with poor outcomes after lung transplantation. Compared to BAL, large airway bronchial wash (LABW) samples the tracheobronchial space where bile acids may be measurable at more clinically relevant levels. We assessed whether LABW bile acids, compared to BAL bile acids, are more strongly associated with poor clinical outcomes in lung transplant recipients.

Methods

Concurrently obtained BAL and LABW at 3 months post-transplant from a retrospective cohort of 61 lung transplant recipients were analyzed for taurocholic acid (TCA), glycocholic acid (GCA), and cholic acid by mass spectrometry and 10 inflammatory proteins by multiplex immunoassay. Associations between bile acids with inflammatory proteins and acute lung allograft dysfunction were assessed using Spearman correlation and logistic regression, respectively. Time to chronic lung allograft dysfunction and death were evaluated using multivariable Cox proportional hazards and Kaplan–Meier methods.

Results

Most bile acids and inflammatory proteins were higher in LABW than in BAL. LABW bile acids correlated with inflammatory proteins within and between sample type. LABW TCA and GCA were associated with acute lung allograft dysfunction (OR = 1.368; 95%CI = 1.036–1.806; P = 0.027, OR = 1.064; 95%CI = 1.009–1.122; P = 0.022, respectively). No bile acids were associated with chronic lung allograft dysfunction. Adjusted for risk factors, LABW TCA and GCA predicted death (HR = 1.513; 95%CI = 1.014–2.256; P = 0.042, HR = 1.597; 95%CI = 1.078–2.366; P = 0.020, respectively). Patients with LABW TCA in the highest tertile had worse survival compared to all others.

Conclusions

LABW bile acids are more strongly associated than BAL bile acids with inflammation, acute lung allograft dysfunction, and death in lung transplant recipients. Collection of LABW may be useful in the evaluation of microaspiration in lung transplantation and other respiratory diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02131-5.

Impact of gastroesophageal reflux disease on idiopathic pulmonary fibrosis and lung transplant recipients

PURPOSE OF REVIEW

Idiopathic pulmonary fibrosis (IPF) is a prevalent subset of interstitial lung disease (ILD) that often progresses to require lung transplantation. Gastroesophageal reflux disease (GERD) is common in the IPF population, and GER-related micro-aspiration appears to be an important risk factor for IPF pathogenesis and for the deterioration of transplanted lung function.

RECENT FINDINGS

Many patients with IPF have elevated esophageal acid exposure on reflux testing despite having no or minimal symptoms. Studies on the effects of medical GERD therapy on IPF-related outcomes have had mixed results. Antireflux surgery is safe in appropriately selected IPF patients, and appears to have potential for slowing the decline of lung function. GERD can persist, improve or develop after lung transplantation, and the presence of GERD is associated with allograft injury and pulmonary function decline in lung transplant recipients.

SUMMARY

Clinicians should have a low threshold to assess for objective evidence of GERD in IPF patients. Antireflux surgery in IPF patients with GERD appears to improve lung function, but further studies are needed before surgical treatment can be recommended routinely in this setting. In lung transplant recipients, reflux testing after transplant is the most accurate way to guide GERD treatment decisions.

Prevalence of Micro-Aspiration of Bile Acids in Patients with Primary Lung Cancer: A Cross-Sectional Study

Background

Lung cancer remains a serious public health problem and is the first cause of cancer-related death worldwide. There is some evidence suggests that bile acid micro-aspiration may contribute to the development of lung diseases. This study aimed to assess the prevalence of micro-aspiration of bile acids in patients with primary lung cancer.

Methods

In a cross-sectional study, 52 patients with primary lung cancer referred to a teaching hospital affiliated with Kerman University of Medical Sciences, Kerman, Iran were enrolled. Patients with pathology-confirmed lung cancer who did not receive specific treatment were included in the present study. All patients underwent bronchoscopy and the levels of bile acid was assessed in their Broncho-Alveolar Lavage (BAL) samples.

Results

According to the results, 53.85% of patients were in the age group of 40 to 59 years. Of the participants, 88.46% were male, 82.69% were smokers, and 69.23% were opium addicted. The most common presenting clinical symptoms of patients were heartburn (61.55%), hoarseness (17.31%), and epigastric pain (9.61%), respectively. Ninety-two point thirty-two percent of patients had endobronchial lesions in bronchoscopy. Squamous cell carcinoma, small-cell lung carcinoma and adenocarcinoma accounts for 48.08%, 34.61% and 17.31% of all cases of lung cancer, respectively. Bile acids were found in the BAL sample of all patients with primary lung cancer. The mean Bile acids levels in patients were 63.42 (SD=7.03) µmol/Lit.

Conclusion

According to the results of present study, there was a micro-aspiration of bile acids in all patients with primary lung cancer that may participate in shaping early events in the etiology of primary lung cancer. It seems that developing clinical strategies preventing the micro-aspiration of bile acids into the lungs could remove a key potential trigger in this process.

Cough hypersensitivity and chronic cough

Chronic cough is globally prevalent across all age groups. This disorder is challenging to treat because many pulmonary and extrapulmonary conditions can present with chronic cough, and cough can also be present without any identifiable underlying cause or be refractory to therapies that improve associated conditions. Most patients with chronic cough have cough hypersensitivity, which is characterized by increased neural responsivity to a range of stimuli that affect the airways and lungs, and other tissues innervated by common nerve supplies. Cough hypersensitivity presents as excessive coughing often in response to relatively innocuous stimuli, causing significant psychophysical morbidity and affecting patients' quality of life. Understanding of the mechanisms that contribute to cough hypersensitivity and excessive coughing in different patient populations and across the lifespan is advancing and has contributed to the development of new therapies for chronic cough in adults. Owing to differences in the pathology, the organs involved and individual patient factors, treatment of chronic cough is progressing towards a personalized approach, and, in the future, novel ways to endotype patients with cough may prove valuable in management.

Delayed Gastric Emptying in Prelung Transplant Patients Is Associated With Posttransplant Acute Cellular Rejection Independent of Reflux

GOAL

The goal of this study was to evaluate the relationship between pretransplant delayed gastric emptying (DGE) and posttransplant acute cellular rejection (ACR) in lung transplant recipients.

BACKGROUND

DGE is very prevalent (23% to 91%) after lung transplantation but pretransplant prevalence has not been well studied. DGE may lead to poor posttransplant outcomes by predisposing to microaspiration. Pretransplant testing for DGE may help identify patients at risk for negative posttransplant outcomes including ACR.

MATERIALS AND METHODS

A retrospective review of a prospectively collected database of consecutive patients undergoing prelung transplant evaluation at a tertiary referral center from 2010 to 2015 was performed. Patients with pretransplant gastric emptying scintigraphy were included in the study. ACR diagnosis was made using International Society for Heart and Lung Transplantation (ISHLT) histologic criteria. Typical gastroparesis symptoms at the time of gastric emptying scintigraphy and pretransplant 24-hour pH impedance monitoring (MII-pH) data was collected. Logistic regression was used for multivariate analysis. Subgroup analyses were performed to account for gastroesophageal reflux (GER).

RESULTS

A total of 83 subjects (18 with DGE, 51.8% male, mean age: 53.6 y) met the criteria for inclusion. Patients with DGE were more likely to have typical symptoms of gastroparesis, though 61.1% of DGE patients were asymptomatic. ACR was more prevalent in patients with DGE (33.3% vs. 12.3%, P=0.04). This correlation was independent of GER as measured by MII-pH on subgroup analysis (75% vs. 14.3%, n=0.02).

DISCUSSION

Lung transplant recipients with pretransplant DGE have a higher incidence of ACR, independent of GER. Routine pretransplant testing for DGE may help identify patients at greater risk for adverse posttransplant outcomes as the majority of patients with DGE are asymptomatic.

Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Acute exacerbation is a major cause of morbidity and mortality in patients with idiopathic pulmonary fibrosis. Although the real nature of it is still not clear and there is no proven effective therapy, progress has been made since the consensus definition and diagnostic criteria were proposed. The trial results of several new innovative therapies in idiopathic pulmonary fibrosis have suggested a potential for benefit in acute exacerbation of idiopathic pulmonary fibrosis, leading to double blind randomized clinical trials in this area. This article reviews the present knowledge on acute exacerbation of idiopathic pulmonary fibrosis, focusing on the triggering factors and treatment.

Sorting out the Relationship Between Esophageal and Pulmonary Disease

The aim of this review is to explore the relationship between esophageal syndromes and pulmonary diseases considering the most recent data available. Prior studies have shown a close relationship between lung diseases such as asthma, chronic obstructive pulmonary disorders (COPD), Idiopathic pulmonary fibrosis (IPF), and lung transplant rejection and esophageal dysfunction. Although the association has long been demonstrated, the exact relationship remains unclear. Clinical experience has shown a bidirectional relationship where esophageal disease may influence the outcomes of pulmonary disease and vice versa. The impact of esophageal dysfunction on pulmonary disorders may also be related to 2 different mechanisms: the reflux pathway leading to microaspiration and the reflex pathway triggering vagally mediated airway reactions. The aim of this review is to further explore these relationships and pathophysiologic mechanisms. Specifically, we discuss the proposed hypotheses for the relationship between the 2 diseases, as well as the pathophysiology and new developments in clinical management.

Foregut Dysmotility in the Lung Transplant Patient

PURPOSE OF REVIEW

To explore the role of upper gastrointestinal disease in the clinical course of lung transplant patients - including its pathophysiology, diagnostic testing, and treatment options.

RECENT FINDINGS

Gastroesophageal reflux disease (GERD) and foregut motility disorders are more prevalent among end-stage lung disease patients and are associated with poorer outcomes in lung transplant recipients. A proposed mechanism is the exposure of the lung allograft to aspirated contents, resulting in inflammation and rejection. Diagnostic tools to assess for these disorders include multichannel intraluminal impedance and pH (MII-pH) testing, high resolution esophageal manometry (HREM), and gastric emptying scintigraphy. The main treatment options are medical management with acid suppressants and/or prokinetic agents and anti-reflux surgery. In particular, data support the use of early anti-reflux surgery to improve outcomes. Newer diagnostic tools such as MII-pH testing and HREM allow for the identification of both acid and non-acid reflux and esophageal motility disorders, respectively. Recent studies have demonstrated that early anti-reflux surgery within six months post-transplant better protects against allograft injury and pulmonary function decline when compared to late surgery. However, further prospective research is needed to evaluate the short and long-term outcomes of these diagnostic approaches and interventions.

[Treatment of GERD in asthma]

Gastro-oesophageal reflux disease (GORD) is one of the most frequent conditions associated with asthma. GORD has an impact on asthma control and quality of life of asthmatic patients. Its treatment relies on lifestyle modifications, anti-acidic treatment with proton pump inhibitors (PPI) and/or surgical management by fundoplication in some situations. The impact of lifestyle modifications has not been analysed on asthma outcomes alone. Several randomised controlled trials assessed the efficacy of PPI on asthma control, peak expiratory flow and/or quality of life. The impact of fundoplication in asthma has mainly been analysed in retrospective or prospective observational studies. This review highlights the limited impact of GORD treatment on asthma control. Current guidelines are to restrict GORD treatment in asthma to asthmatic patients with actual symptomatic GORD. Given the lack of controlled studies, the place of surgical management of GORD in asthma is currently not defined.

Gastroesophageal Reflux and Esophageal Motility Disorder After Lung Transplant: Influence on the Transplanted Graft

BACKGROUND

Esophageal pathology has been identified as a bad prognostic factor in lung transplantation (LTx). This study aims to assess the esophageal disorders present post-LTx, under treatment with proton pump inhibitors, and their putative impact on the graft.

METHODS

Prospective, observational study of LTx patients. Digestive factors were assessed by manometry and pH-metry at 6 months post-LTx and under proton pump inhibitor treatment. We assessed the association between esophageal disorders and graft function and acute rejection (AR) and chronic lung allograft dysfunction (CLAD).

RESULTS

Out of 76 post-LTx patients, 27% showed gastroesophageal reflux disease (GERD), 55% showed inadequate gastric inhibition, and 59% showed esophageal motility disorders (EMDs). We observed a greater incidence of AR from 3 months post-LTx in the presence of EMD (P ≤ .05). No significant differences were observed in GERD or EMD prevalence or in survival between patients with or without CLAD. The maximum forced expiratory volume in 1 second (FEV1) achieved after bilateral LTx was significantly (P = .022) lower in patients with EMD vs without EMD.

CONCLUSION

At 6 months post-LTx, there is a high percentage of esophageal disorders (GERD and EMDs). No esophageal disorder is associated with CLAD or with survival, although EMDs are associated with a greater incidence of AR and lower graft function.

[Reflux Symptoms - No Difference in Severity and Intensity in Patients with and without Functional Verified Gastroesophageal Reflux Disease]

BACKGROUND

Patients with gastroesophageal reflux disease (GERD) often suffer greatly from their symptoms. The aim of this study was to determine if there is a difference in quality of life and gastrointestinal symptom complexes between patients with purely functional complaints and patients with objective GERD.

MATERIAL AND METHODS

We included all patients with typical reflux symptoms, who had a GERD examination in 2017 at our department. All patients underwent high resolution manometry, 24-h-pH-metry impedance measurement and gastroscopy. Quality of life was assessed using the Gastrointestinal Quality of Life Index (GIQLI) and gastrointestinal symptoms were rated by a symptom checklist (SCL), assessing the severity and intensity of 14 different symptoms. Based on the results of the 24-h-pH-metry impedance measurement, patients were divided into 2 groups: patients with functional reflux symptoms and patients with true GERD. These two groups were compared.

RESULTS

Complete data were available in 162 patients, of whom 86 (52.2%) were objectively suffering from reflux (DeMeester score mean: 37.85; SD ± 29.11) and 76 (46.1%) had a normal DeMeester score (Mean: 7.01; SD ± 4.09). No significant difference in quality of life was found between the two groups (mean GIQLI of GERD patients: 94.81, SD ± 22.40, and mean GIQLI of patients with functional reflux symptoms: 95.26, SD ± 20.33, p = 0.988). Furthermore, no significant difference could be found in the evaluated symptoms (mean general SCL score of GERD patients: 46.97; SD ± 29.23; patients with functional reflux symptoms: 48.03; SD ± 29.17, p = 0.827).

CONCLUSION

Patients with functional complaints suffer just as much from their symptoms as patients with objectively diagnosed GERD. Differentiation between gastroesophageal reflux disease and functional reflux symptoms is only possible by means of functional diagnostic testing.

Female reproductive health in cystic fibrosis

Women with cystic fibrosis (CF) are living longer and healthier lives, and opportunities for childbearing are increasingly promising. However, this population can also face sexual and reproductive health concerns, including menstrual irregularities, unplanned pregnancies, infertility and pregnancy complications. Additionally, more women are entering menopause and are at risk for the consequences of estrogen deficiency. The exact mechanisms involved in female reproductive health conditions in CF are not clearly understood, but are thought to include cystic fibrosis transmembrane regulator (CFTR)-mediated abnormalities, changes in female sex hormones, and other CF health-related factors. In the era of CFTR modulator therapy, new data are necessary to understand the impact of CFTR modulation on contraceptive effectiveness, fertility, and pregnancy outcomes to help guide future clinical care. This article reviews the current scientific knowledge of major reproductive health issues for women with CF.

Current therapies for gastro-oesophageal reflux in the setting of chronic lung disease: state of the art review

The inter-relationship between chronic respiratory disease and reflux disease in the airway reflux paradigm is extremely complex and remains poorly characterised. Reflux disease is reported to cause or contribute to the severity of a number of respiratory tract diseases including laryngeal disorders, sinusitis, chronic cough, asthma, COPD, idiopathic pulmonary fibrosis, cystic fibrosis, bronchiectasis and bronchiolitis obliterans post lung transplant. It is now appreciated that reflux disease is not simply caused by liquid acid reflux but rather by a variety of chemical refluxates originating from the stomach and duodenum due to a number of different mechanisms. Reflux disease can be challenging to diagnose, particularly proving its role in the causation of direct respiratory epithelial damage. Significant advances in oesophageal assessment and gastric biomarkers have emerged in recent years as our understanding increases. There are a number of treatments available for reflux disease, both medical and surgical, but there is a paucity of large randomised trials to evaluate their efficacy in the setting of chronic respiratory disease. Everyday clinical practice, however, informs us that treatment failure in reflux disease is common. This clinical review summarises associations between reflux disease in the setting of chronic respiratory diseases and examines available evidence regarding potential therapeutic strategies.

Gastro-oesophageal reflux disease is prevalent among patients with chronic respiratory disease. A number of medical and surgical treatment options are available for GORD. This review examines available evidence in the setting of chronic lung disease.https://bit.ly/34TcMJS

Extraesophageal syndrome of gastroesophageal reflux: relationships with lung disease and transplantation outcome

Gastroesophageal reflux disease (GERD) is prevalent and may be associated with both esophageal and extraesophageal syndromes, which include various pulmonary conditions. GERD may lead to pulmonary complications through the "reflux" (aspiration) or "reflex" (refluxate-triggered, vagally mediated airway spasm) mechanisms. While GERD may cause or worsen pulmonary disorders, changes in respiratory mechanics due to lung disease may also increase reflux. Typical esophageal symptoms are frequently absent and objective assessment with reflux monitoring is often needed for diagnosis. Impedance monitoring should be considered in addition to traditional pH study due to the involvement of both acidic and weakly acidic/nonacidic reflux. Antireflux therapy may improve outcomes of some pulmonary complications of GERD, although careful selection of a candidate is paramount to successful outcomes. Further research is needed to identify the optimal testing strategy and patient phenotypes that would benefit from antireflux therapy to improve pulmonary outcomes.

International Society for Heart and Lung Transplantation consensus statement for the standardization of bronchoalveolar lavage in lung transplantation

Bronchoalveolar lavage (BAL) is a key clinical and research tool in lung transplantation (LTx). However, BAL collection and processing are not standardized across LTx centers. This International Society for Heart and Lung Transplantation-supported consensus document on BAL standardization aims to clarify definitions and propose common approaches to improve clinical and research practice standards. The following 9 areas are covered: (1) bronchoscopy procedure and BAL collection, (2) sample handling, (3) sample processing for microbiology, (4) cytology, (5) research, (6) microbiome, (7) sample inventory/tracking, (8) donor bronchoscopy, and (9) pediatric considerations. This consensus document aims to harmonize clinical and research practices for BAL collection and processing in LTx. The overarching goal is to enhance standardization and multicenter collaboration within the international LTx community and enable improvement and development of new BAL-based diagnostics.

Pepsin and oropharyngeal pH monitoring to diagnose patients with laryngopharyngeal reflux

Objectives

The aim of this study was to compare the diagnostic accuracy of salivary pepsin with oropharyngeal pH monitoring using the Restech measurement system (Dx‐pH) for the diagnosis of laryngopharyngeal reflux (LPR).

Study Design

Prospective cohort study.

Methods

Seventy patients with primary symptoms related to LPR underwent gastroscopy, high‐resolution manometry, pH throughout 24‐hour monitoring (MII‐pH), and barium esophagography between October 2015 and May 2018. In addition, an ear, nose, and throat examination was performed, including assessment of Belafsky Reflux Finding Score (RFS). Clinical symptoms were evaluated with the Belafsky Reflux Symptom Index (RSI) and the Gastrointestinal Quality of Life Index (GIQLI). Simultaneous to MII‐pH, pepsin determination and Dx‐pH were performed.

Results

Of 70 patients, 41 (58.6%) subjects with a pathological DeMeester score showed higher mean values of pepsin (mean value: 216 ng/mL, 95% confidence interval [CI]: 172 to 260), compared to patients with a normal DeMeester score (mean value: 161 ng/mL, 95% CI: 115 to 207). Salivary pepsin showed a specificity of 86.2% and sensitivity of 41.5% for diagnosing LPR using the optimal cutoff value of 216 ng/mL. Furthermore, a significant correlation between the values of salivary pepsin and the RSI score was seen in patients with pathological results in MII‐pH (r = 0.344; P = 0.046).

However, elevated Dx‐pH measurements showed no significant correlation with either MII‐pH, RSI score, RFS score, or GIQLI score, or with the results of pepsin measurement.

Conclusion

Pepsin measurement in saliva could be an alternative tool to assist office‐based diagnosis of LPR, whereas Dx‐pH does not seem to be an adequate test.

Level of Evidence

2B Laryngoscope, 130:1780–1786, 2020

Regeneration of severely damaged lungs using an interventional cross-circulation platform

The number of available donor organs limits lung transplantation, the only lifesaving therapy for the increasing population of patients with end-stage lung disease. A prevalent etiology of injury that renders lungs unacceptable for transplantation is gastric aspiration, a deleterious insult to the pulmonary epithelium. Currently, severely damaged donor lungs cannot be salvaged with existing devices or methods. Here we report the regeneration of severely damaged lungs repaired to meet transplantation criteria by utilizing an interventional cross-circulation platform in a clinically relevant swine model of gastric aspiration injury. Enabled by cross-circulation with a living swine, prolonged extracorporeal support of damaged lungs results in significant improvements in lung function, cellular regeneration, and the development of diagnostic tools for non-invasive organ evaluation and repair. We therefore propose that the use of an interventional cross-circulation platform could enable recovery of otherwise unsalvageable lungs and thus expand the donor organ pool.

Pepsin promotes IL-8 signaling-induced epithelial-mesenchymal transition in laryngeal carcinoma

Background

Laryngopharyngeal 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.

Methods

The 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.

Results

Pepsin 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.

Conclusions

Pepsin 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 material

The online version of this article (10.1186/s12935-019-0772-7) contains supplementary material, which is available to authorized users.

Association between Pepsin in Bronchoalveolar Lavage Fluid and Prognosis of Chronic Fibrosing Interstitial Lung Disease

Chronic fibrosing interstitial lung disease (ILD)s are characterized by chronic progressive fibrosis of lung which include idiopathic pulmonary fibrosis (IPF), nonspecific interstitial pneumonia (NSIP), and connective tissue disease-associated interstitial lung disease (CTD-ILD). IPF is an irreversible fibrotic lung disease which results in respiratory failure. Although NSIP and CTD-ILD can be improved or stable by treatment with corticosteroid or immunosuppressant, some of them progress to fibrotic lung diseases. Aspiration of gastric contents is suggested as an aggravating factor of ILDs. We measured pepsin, a marker of gastric aspiration, in bronchoalveolar lavage (BAL) fluid of chronic fibrosing ILD patients to evaluate the association between BAL fluid pepsin and prognosis of chronic fibrosing ILDs. Patients with chronic fibrosing ILDs, who underwent bronchoscopy between December 2010 and April 2015 were prospectively enrolled. Pepsin levels were measured using a commercial ELISA kit. Clinical characteristics, lung function data, and mortality were analyzed. Fifty-one patients with chronic fibrosing ILDs were enrolled (26 with IPF, 15 with NSIP, and 10 with CTD-ILD). Pepsin levels in BAL fluid were 69.87 ± 74.16 ng/mL in IPF, 110.68 ± 94.93 ng/mL in NSIP, and 101.87 ± 88.44 ng/mL in CTD-ILDs. There were no statistically significant differences in BAL fluid pepsin levels among patients with the different chronic fibrosing ILDs. In multivariate regression analysis, higher BAL pepsin levels were associated with higher mortality (adjusted odds ratio [aOR] = 1.021, p = 0.025). BAL fluid pepsin may be used as a prognostic marker for predicting mortality in chronic fibrosing ILD patients.

Reflux in idiopathic pulmonary fibrosis: treatment informed by an integrated approach

Despite recent therapeutic advances, the prognosis for patients with idiopathic pulmonary fibrosis (IPF) remains poor. The link with gastro-oesophageal reflux disease (GORD) has been identified as a research priority, as GORD appears to be common in IPF and may be associated with adverse outcomes [1]. GORD is often clinically silent in IPF, so detection is challenging [2].

After MDT work-up and review, gastro-oesophageal reflux and pulmonary aspiration were found to be common in IPF patients; surgery was recommended in only 10%http://ow.ly/rO3T30lU17o

Aspiration Pneumonia and Related Syndromes

Aspiration is a syndrome with variable respiratory manifestations that span acute, life-threatening illnesses, such as acute respiratory distress syndrome, to chronic, sometimes insidious, respiratory disorders such as aspiration bronchiolitis. Diagnostic testing is limited by the insensitivity of histologic testing, and although gastric biomarkers for aspiration are increasingly available, none have been clinically validated. The leading mechanism for microaspiration is thought to be gastroesophageal reflux disease, largely driven by the increased prevalence of gastroesophageal reflux across a variety of respiratory disorders, including chronic obstructive pulmonary disease, asthma, idiopathic pulmonary fibrosis, and chronic cough. Failure of therapies targeting gastric acidity in clinical trials, in addition to increasing concerns about both the overuse of and adverse events associated with proton pump inhibitors, raise questions about the precise mechanism and causal link between gastroesophageal reflux and respiratory disease. Our review summarizes key aspiration syndromes with a focus on reflux-mediated aspiration and highlights the need for additional mechanistic studies to find more effective therapies for aspiration syndromes.

Gastric Aspiration and Its Role in Airway Inflammation

Gastro-Oesophageal Reflux (GOR) has been associated with chronic airway diseases while the passage of foreign matter into airways and lungs through aspiration has the potential to initiate a wide spectrum of pulmonary disorders. The clinical syndrome resulting from such aspiration will depend both on the quantity and nature of the aspirate as well as the individual host response. Aspiration of gastric fluids may cause damage to airway epithelium, not only because acidity is toxic to bronchial epithelial cells but also due to the effect of digestive enzymes such as pepsin and bile salts. Experimental models have shown that direct instillation of these factors to airways epithelia cause damage with a consequential inflammatory response. The pathophysiology of these responses is gradually being dissected, with better understanding of acute gastric aspiration injury, a major cause of acute lung injury, providing opportunities for therapeutic intervention and potentially, ultimately, improved understanding of the chronic airway response to aspiration. Ultimately, clarification of the inflammatory pathways which are related to micro-aspiration via pepsin and bile acid salts may eventually progress to pharmacological intervention and surgical studies to assess the clinical benefits of such therapies in driving symptom improvement or reducing disease progression.

Lung Transplant in Patients with Scleroderma Compared with Pulmonary Fibrosis. Short- and Long-Term Outcomes

RATIONALE

Patients with advanced lung disease due to systemic sclerosis have long been considered suboptimal and often unacceptable candidates for lung transplant.

OBJECTIVES

To examine post-lung transplant survival of patients with systemic sclerosis compared with patients with pulmonary fibrosis and to identify risk factors for 1-year mortality.

METHODS

In a retrospective cohort study, we compared post-lung transplant outcomes of 72 patients with scleroderma with those of 311 patients with pulmonary fibrosis between June 2005 and September 2013 at our institution. Actuarial survival estimates were calculated using Kaplan-Meier curves. In Cox regression models, we determined risk factors for post-transplant mortality, controlling for whether patients had scleroderma or pulmonary fibrosis.

MEASUREMENTS AND MAIN RESULTS

Post-transplant survival did not differ significantly between scleroderma and pulmonary fibrosis at year 1 (81% scleroderma vs. 79% pulmonary fibrosis; P = 0.743), at year 5 conditional on 1-year survival (66% vs. 58%; P = 0.249), or overall (P = 0.385). In multivariate analysis, body mass index greater than or equal to 35 kg/m(2) predicted poor 1-year survival in pulmonary fibrosis (hazard ratio, 2.76; P = 0.003). Acute cellular rejection-free survival did not differ significantly between the scleroderma and pulmonary fibrosis cohorts. Patients with scleroderma had significantly better bronchiolitis obliterans syndrome stage 1 or higher-free survival than did patients with pulmonary fibrosis.

CONCLUSIONS

Our findings that 1- and 5-year survival rates of patients with scleroderma were similar to those of patients with pulmonary fibrosis indicate that lung transplant is a reasonable treatment option in selected patients with scleroderma.

Sep70/Pepsin expression in hypopharynx combined with hypopharyngeal multichannel intraluminal impedance increases diagnostic sensitivity of laryngopharyngeal reflux

BACKGROUND

Improved methods of diagnosis of laryngopharyngeal reflux (LPR) would enable surgeons to better identify patients who may benefit from antireflux surgery (ARS). The objective of the present study was to assess if hypopharyngeal Pepsin and Sep70 expression combined with hypopharyngeal multichannel intraluminal impedance (HMII) has the potential to increase diagnostic sensitivity of LPR.

METHODS

This study was performed on patients who underwent unsedated transnasal endoscopy with hypopharyngeal biopsy and 24-h HMII to determine abnormal proximal exposure (APE) and DeMeester score (DMS) from 2013 to 2016. Pepsin and Sep70 protein expression was assessed by Western blots of biopsy specimens. The outcomes of ARS were assessed using reflux symptom index (RSI). HMII APE classification, Sep 70, and Pepsin protein levels were compared in normative and symptomatic LPR patients and further analyzed alongside quality of life changes following ARS.

RESULTS

Of 30 subjects enrolled, 23 were excluded for abnormal HMII results or endoscopic evidence of esophagitis. Seven subjects and 105 patients were included in the normative and symptomatic groups, respectively. Compared to the normative group, only Pepsin expression was significantly higher in the symptomatic group [APE+/LPR+ (p = 0.000), APE+/LPR- (p = 0.001), and APE- (p = 0.047)]. Further, the ratio of Sep70/Pepsin was significantly lower in the symptomatic group [APE+/LPR+ (p = 0.008), APE+/LPR- (p = 0.000), and APE- (p = 0.050)], and a cutoff ratio for a diagnosis of LPR was established as < 158. Of 105 symptomatic patients, 48 patients underwent ARS. Of these, 17 patients had complete pre- and post-RSI questionnaires. LPR symptoms improved in 15 (88%), of whom 2 were APE- but met criteria for a diagnosis of LPR based on the Sep70/Pepsin cutoff.

CONCLUSIONS

The identified Sep70/Pepsin ratio may serve as a reliable biomarker for the diagnosis of LPR. As a result, this may help identify additional patients who have a false-negative HMII result due to the 24-h testing window.

The diagnostic value of pepsin detection in saliva for gastro-esophageal reflux disease: a preliminary study from China

Background

None of current diagnostic methods has been proven to be a reliable tool for gastro-esophageal reflux disease (GERD). Pepsin in saliva has been proposed as a promising diagnostic biomarker for gastro-esophageal reflux. We aimed to determine the diagnostic value of salivary pepsin detection for GERD.

Methods

Two hundred and fifty patients with symptoms suggestive of GERD and 35 asymptomatic healthy volunteers provided saliva on morning waking, after lunch and dinner for pepsin determination using the Peptest lateral flow device. All patients underwent 24-h multichannel intraluminal impedance pH (24-h MII-pH) monitoring and upper gastrointestinal endoscopy. Based on 24-h MII-pH and endoscopy study, patients were defined as GERD (abnormal MII-pH results and/or reflux esophagitis) and non-GERD otherwise.

Results

Patients with GERD had a higher prevalence of pepsin in saliva and higher pepsin concentration than patients with non-GERD and healthy controls (P < 0.001 for all). The pepsin test had a sensitivity of 73% and a specificity of 88.3% for diagnosing GERD using the optimal cut-off value of 76 ng/mL. Postprandial saliva samples collected when the symptoms occurred had a more powerful ability to identify GERD.

Conclusions

Salivary pepsin test had moderate diagnostic value for GERD. It may be a promising tool to replace the use of currently invasive tools with advantages of non-invasive, easy to perform and cost effective.

Trial registration

ChiCTR-DDD-16009506 (date of registration: October 20, 2016).

Update in Chronic Lung Allograft Dysfunction

Chronic lung allograft dysfunction (CLAD) is the major limitation to posttransplant survival. This review highlights the evolving definition of CLAD, risk factors, treatment, and expected outcomes after the development of CLAD.

Impaired Esophageal Motility and Clearance Post-Lung Transplant: Risk For Chronic Allograft Failure

OBJECTIVES

Gastroesophageal reflux is common in patients post-lung transplantation (LTx) and thus considered a risk factor for aspiration and consequently allograft rejection and the development of chronic allograft failure. However, evidence supporting this remains unclear and often contradictory. Our aim was to examine the role played by esophageal motility on gastroesophageal reflux exposure, along with its clearance and that of boluses swallowed, and the relationship to development of obstructive chronic lung allograft dysfunction (o-CLAD).

METHODS

Patients post-LTx (n=50, 26 female; mean age 55 years (range, 20-73 years)) completed high-resolution impedance manometry and 24-h pH/impedance. Esophageal motility abnormalities were classified based upon the Chicago Classification version 3.0.

RESULTS

Esophagogastric junction outflow obstruction alone (EGJOOa) (P=0.01), incomplete bolus transit (IBT) (P=0.006) and proximal reflux (P=0.042) increased the risk for o-CLAD. Patients with EGJOOa were most likely to present with o-CLAD (77%); despite being less likely to exhibit abnormal numbers of reflux events (10%) compared with those with normal motility (o-CLAD: 29%, P<0.05; abnormal reflux events: 64%, P<0.05). Patients with EGJOOa had lower total reflux bolus exposure time than those with normal motility (0.6 vs. 1.5%; P<0.05). In addition, poor esophageal clearance documented by abnormal post-reflux swallow-induced peristaltic wave index associated with o-CLAD; inversely correlating with the proportion of reflux events reaching the proximal esophagus (r=-0.251; P=0.052).

CONCLUSIONS

These observations support esophageal dysmotility, especially EGJOOa, and impaired clearance of swallowed bolus or refluxed contents, more so than just the presence of gastroesophageal reflux alone, as important risk factors in the development of o-CLAD.

Pepsin as a Marker of Extraesophageal Reflux

Diagnosis of extraesophageal reflux (EER) currently relies on tools designed for diagnosis of gastroesophageal reflux. Such tools lack the sensitivity and reproducibility to detect the less frequent and mildly acidic reflux associated with upper airway disease. Pepsin has been posited to be a reliable biological marker of EER. Our aim was to present a comprehensive literature review of the use of pepsin as a diagnostic marker of EER. Two methods are typically used for detection of pepsin in the airways: enzymatic and immunologic. The limitations, advantages, and examples of use of each are discussed. Pepsin assay has been used to identify refluxate in trachea, lung, sinus, middle ear, combined sputum and saliva, and breath condensate. An immunologic pepsin assay of combined sputum and saliva was determined to be 100% sensitive and 89% specific for detection of EER (based on pH-metry), and an enzymatic test of nasal lavage fluid (100% sensitivity and 92.5% specificity) demonstrated an increased incidence of EER in patients with chronic rhinosinusitis. Pepsin assay identified tracheal pepsin to be an indicator of bronchopulmonary dysplasia and related mortality risk in ventilated preterm infants. Pepsin assay is a useful tool for correlation of reflux with airway disease and is a reliable diagnostic marker of EER.

Role of gastroesophageal reflux disease in lung transplantation

Lung transplantation is one of the highest risk solid organ transplant modalities. Recent studies have demonstrated a relationship between gastroesophageal reflux disease (GERD) and lung transplant outcomes, including acute and chronic rejection. The aim of this review is to discuss the pathophysiology, evaluation, and management of GERD in lung transplantation, as informed by the most recent publications in the field. The pathophysiology of reflux-induced lung injury includes the effects of aspiration and local immunomodulation in the development of pulmonary decline and histologic rejection, as reflective of allograft injury. Modalities of reflux and esophageal assessment, including ambulatory pH testing, impedance, and esophageal manometry, are discussed, as well as timing of these evaluations relative to transplantation. Finally, antireflux treatments are reviewed, including medical acid suppression and surgical fundoplication, as well as the safety, efficacy, and timing of such treatments relative to transplantation. Our review of the data supports an association between GERD and allograft injury, encouraging a strategy of early diagnosis and aggressive reflux management in lung transplant recipients to improve transplant outcomes. Further studies are needed to explore additional objective measures of reflux and aspiration, better compare medical and surgical antireflux treatment options, extend follow-up times to capture longer-term clinical outcomes, and investigate newer interventions including minimally invasive surgery and advanced endoscopic techniques.

The Potential Role of Aspiration in the Asthmatic Airway

BACKGROUND

Many people with asthma remain suboptimally controlled despite current treatments. Reasons include comorbidities that could aggravate asthma, including gastroesophageal reflux. We aimed to investigate whether aspiration occurs in patients with asthma and, if so, does it correlate with asthma control?

METHODS

Patients had Asthma Control Questionnaire 7 (ACQ-7), fractional exhaled nitric oxide, and spirometry performed to characterize their level of asthma control. Barium swallow with provocation was performed to assess for predisposition to aspiration. Patients underwent bronchoscopic investigation, with BAL pepsin measured as a marker of aspiration.

RESULTS

Seventy-eight patients stratified by disease severity (Global Initiative for Asthma) into mild (35.8%), moderate (21.7%) and severe (42.3%) were studied. Pepsin was detectable in BAL in 46/78 (58.9%). There were no differences between pepsin levels in patients with different disease severity. Furthermore, no significant associations were seen between pepsin level and measures of asthma control, FEV₁, ACQ-7 or exacerbation frequency. Similarly no associations were found with adjustments for smoking history, BMI, proton pump inhibitor use, eosinophil count or IgE. When stratified into eosinophilic or neutrophilic asthmatic populations on the basis of BAL, there was no relationship to detected pepsin concentrations. A positive barium swallow (seen in 33/60 patients) did not correlate with BAL pepsin level and we found no significant association between barium swallow result and ACQ-7, Global Initiative for Asthma, exacerbation frequency or FEV₁ using either univariate or multivariate analyses.

CONCLUSIONS

This study suggests that the importance of aspiration on current asthma symptom control and exacerbation rate may be overstated. However, this study did not address the role of aspiration and future risk of exacerbation.

Pepsin as a biomarker for laryngopharyngeal reflux in children with laryngomalacia

OBJECTIVES/HYPOTHESIS

Laryngomalacia is a common cause of newborn stridor. Laryngopharyngeal reflux (LPR) has been associated with laryngomalacia. Although pepsin, a component of LPR, has been associated with inflammatory diseases of the aerodigestive tract, its presence in the airways of laryngomalacia patients is unknown.

STUDY DESIGN

Prospective case-control study comparing patients under age 3 years with laryngomalacia to children without laryngomalacia.

METHODS

Children less than 3 years old undergoing supraglottoplasty for laryngomalacia or surgery unrelated to the airway, without a history of laryngomalacia, reflux, or respiratory disease, were offered enrollment. Supraglottic lavage samples (3 mL) were obtained from all subjects. Two-millimeter arytenoid biopsies were collected from laryngomalacia patients. Pepsin Western blot and enzyme-linked immunosorbent assay were performed.

RESULTS

Ten laryngomalacia and five control subjects were enrolled. Pepsin was detected in lavages of laryngomalacia patients (8/10) but absent in controls (0/5; P = .007). Pepsin was observed more frequently in lavages (8/10) than biopsies (4/10; P = .046) of laryngomalacia subjects. Higher median pepsin concentration was observed in laryngomalacia than control lavages (P = .025).

CONCLUSIONS

Pepsin in supraglottic specimens demonstrated an association with laryngomalacia, supporting a role for refluxed pepsin in laryngomalacia. These data corroborate previous work implicating pepsin in inflammatory diseases of the upper airways. Further studies are warranted to investigate the contribution of pepsin to the pathophysiology of laryngomalacia.

LEVEL OF EVIDENCE

3b. Laryngoscope, 127:2413-2417, 2017.

The Role of Microaspiration in the Pathogenesis of Gastroesophageal Reflux-related Chronic Cough

Background/Aims

Gastroesophageal reflux disease (GERD) is one of the main causes of chronic cough. We evaluated the role of microaspiration in the pathogenesis of reflux-related cough by determining the amount of lipid-laden macrophages (LLMs) in bronchoalveolar lavage (BAL) specimens.

Methods

A total of 161 cases of chronic cough were evaluated, and 36 patients (average age 48.2 years) were recruited for this single center prospective study. Patients with a history of smoking, angiotensin converting enzyme inhibitor usage, any abnormality on pulmonary function tests, abnormal chest X-rays, occupational or environmental exposures, or upper airway cough syndrome were excluded. GERD was evaluated by 24-hour esophageal impedance-pH monitoring. BAL specimens for LLM determination were obtained from 34 patients by flexible bronchoscopy.

Results

Patients with pathological intra-esophageal reflux according to multichannel intraluminal impedance and pH monitoring had higher LLM positivity in BAL specimens than patients without pathological reflux (8/14 in reflux positive group vs 1/22 in reflux negative group; P = 0.004). The BAL cell distribution was not different between the 2 groups (P = 0.574 for macrophages, P = 0.348 for lymphocytes, P = 0.873 for neutrophils and P = 0.450 for eosinophils).

Conclusions

Our results confirm the role of the microaspiration of refluxate in the pathogenetic mechanism of chronic cough. While bronchoscopy is indicated in patients with chronic cough, in addition to the routine airway evaluation, BAL and LLM detection should be performed. LLM can be used to diagnose aspiration in reflux-related chronic cough. Future studies are needed to evaluate the response to anti-reflux medications or surgery in patients with LLM positivity.

Esophageal Dysmotility, Gastro-esophageal Reflux Disease, and Lung Transplantation: What Is the Evidence?

Lung transplantation is an effective and life-prolonging therapy for patients with advanced lung disease (ALD). However, long-term patient survival following lung transplantation is primarily limited by development of an inflammatory and fibrotic process involving the lung allograft known as bronchiolitis obliterans syndrome (BOS). Although the precise cause of BOS remains uncertain and is likely multifactorial, chronic aspiration of gastro-duodenal contents is one possible contributing factor. Multiple small, cross-sectional studies performed over the past two decades have reported a high prevalence of gastro-esophageal reflux disease (GERD) and esophageal dysmotility in the ALD population and several investigations suggest the prevalence may increase following lung transplantation. More recent studies evaluating the direct effect of gastro-duodenal contents on airways have demonstrated a possible biologic link between GERD and BOS. Despite the recent advances in our understanding of BOS, further investigations are needed to establish GERD as a causative factor in its development. This review will discuss the existing literature that has identified an association of GERD with ALD and post-transplant populations, with a focus on recent advances in the field.