Biomarkers for gastroesophageal reflux in respiratory diseases

Pulmonary and esophageal function in lung transplantation: Fundamental principles and clinical application

The lungs and esophagus have a close anatomical and physiological relationship. Over the years, reflux-induced pulmonary injury has gained wider recognition, but the full effects of pulmonary disease on esophageal function are still unknown. Intrathoracic pressure dynamics potentially affect esophageal function, especially in patients with end-stage lung disease, both obstructive and restrictive. Lung transplantation is the only viable option for patients with end-stage pulmonary disease and has provided us with a unique opportunity to study these effects as transplantation restores the intrathoracic environment. Esophageal and foregut functional testing before and after transplantation provide insights into the pathophysiology of the foregut-pulmonary axis, such as how underlying pulmonary disease and intrathoracic pressure changes affect esophageal physiology. This review summarizes the available literature and shares the research experience of a lung transplant center, covering topics such as pre- and posttransplant foregut function, esophageal motility in lung transplant recipients, immune-mediated mechanisms of graft rejection associated with gastroesophageal reflux, and the role of antireflux surgery in this population.

Gastroesophageal reflux and asthma: when, how, and why

PURPOSE OF REVIEW

Gastro-esophageal reflux is a possible cause of uncontrolled symptoms of asthma and should be actively investigated and treated before severe asthma is diagnosed and biological therapy started.

RECENT FINDINGS

Recent investigations on esophageal function and tissue biomarkers in patients with asthma and associated GERD have established a relevant role for esophageal motility and neuronal sensory abnormalities in linking the two diseases. Characterization of the underpinning inflammatory substrate has showed mixed results as both neutrophilic and eosinophilic type 2 inflammatory changes have been described.

SUMMARY

New findings regarding inflammatory mechanisms in GERD-associated asthma as well as new diagnostic tools to investigate functional esophageal abnormalities and characterize asthma endotype have identified potential treatable traits that may improve the clinical management and outcome of asthmatic patients with GERD.

Association of Bile Acid and Pepsin Micro-aspiration with Chronic Obstructive Pulmonary Disease Exacerbation

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is one of the most common chronic diseases all around the world. One of suggested risk factors for COPD is Gastroesophageal Reflux Disease (GERD). The aim of this study was investigation of the association between micro-aspiration of bile acid and pepsin with exacerbation attacks in COPD patients.

MATERIALS AND METHODS

The present study was a descriptive cross-sectional study. Fifty-two COPD patients were selected by simple sampling from patients referring to the Bessat Lung Clinic. Participants were divided into two groups of with and without COPD exacerbation history in the past year. The severity of the disease was determined based on the GOLD criteria (mild, moderate, severe and very severe). Then, all patients underwent bronchoscopy and the concentrations of bile acid and pepsin were compared in Broncho-Alveolar Lavage Fluid (BALF) of two groups.

RESULTS

The mean of bile acids in the group without COPD exacerbations was lower (27.38±3.26 μmol/Lit) than the group with COPD exacerbations (32.31±5.35 μmol/Lit) and this difference was not significant (P=0.436). The mean of pepsin in the first group was higher (118.46 ±15.44 ng/ml) than the second group (107.88±10.7 ng/ml) and this difference was also not significant (P=0.577).

CONCLUSION

According to the results of this study, there is no association between disease severity and number of exacerbations with micro-aspiration of bile acid and pepsin in COPD patients.

Scintigraphic Evaluation of Gastroesophageal Reflux and Pulmonary Aspiration in Children

Gastroesophageal reflux (GER) and pulmonary aspiration are encountered in children of all ages. Signs, symptoms, and complications vary from mild and transient to severe life-threatening conditions. This review will present relevant clinical information on these conditions as well as common diagnostic procedures. The role of scintigraphic techniques used in the evaluation of these conditions will be discussed in detail including protocols and performance in comparison to other diagnostic methods.

Respiratory symptoms, sleep-disordered breathing and biomarkers in nocturnal gastroesophageal reflux

BACKGROUND

Nocturnal gastroesophageal reflux (nGER) is associated with respiratory symptoms and sleep-disordered breathing (SDB), but the pathogenesis is unclear. We aimed to investigate the association between nGER and respiratory symptoms, exacerbations of respiratory symptoms, SDB and airway inflammation.

METHODS

Participants in the European Community Respiratory Health Survey III in Iceland with nGER symptoms (n = 48) and age and gender matched controls (n = 42) were studied by questionnaires, exhaled breath condensate (EBC), particles in exhaled air (PEx) measurements, and a home polygraphic study. An exacerbation of respiratory symptoms was defined as an episode of markedly worse respiratory symptoms in the previous 12 months.

RESULTS

Asthma and bronchitis symptoms were more common among nGER subjects than controls (54 % vs 29 %, p = 0.01; and 60 % vs 26 %, p < 0.01, respectively), as were exacerbations of respiratory symptoms (19 % vs 5 %, p = 0.04). Objectively measured snoring was more common among subjects with nGER than controls (snores per hour of sleep, median (IQR): 177 (79-281) vs 67 (32-182), p = 0.004). Pepsin (2.5 ng/ml (0.8-5.8) vs 0.8 ng/ml (0.8-3.6), p = 0.03), substance P (741 pg/ml (626-821) vs 623 pg/ml (562-676), p < 0.001) and 8-isoprostane (3.0 pg/ml (2.7-3.9) vs 2.6 pg/ml (2.2-2.9), p = 0.002) in EBC were higher among nGER subjects than controls. Albumin and surfactant protein A in PEx were lower among nGER subjects. These findings were independent of BMI.

CONCLUSION

In a general population sample, nGER is associated with symptoms of asthma and bronchitis, as well as exacerbations of respiratory symptoms. Also, nGER is associated with increased respiratory effort during sleep. Biomarker measurements in EBC, PEx and serum indicate that micro-aspiration and neurogenic inflammation are plausible mechanisms.

Gastroesophageal reflux disease related asthma: From preliminary studies to clinical practice

The diagnosis of asthma requires the presence of episodic respiratory difficulties characterized by variable and reversible airway obstruction. It has a high prevalence worldwide and is traditionally considered to be an allergic disease. Most cases are responsive to treatment with bronchodilators and anti-inflammatories, as recommended by national and international guidelines; however, approximately 10% of asthmatic patients are refractory even to optimal therapy. Gastroesophageal reflux disease (GERD) is a common disorder in asthmatic patients and the two disorders may be linked pathophysiologically. Here we review data from preliminary studies that suggest asthma could be induced or exacerbated by gastroesophageal reflux. The optimal strategies for the diagnosis of GERD-related asthma and its therapy are still debated. However, there is evidence to suggest that antireflux treatment is effective and practical for asthmatic patients with well-defined reflux disease.