Obstructive sleep apnea syndrome may be a significant cause of gastroesophageal reflux disease in older people

Aerodigestive disorders in dogs evaluated for cough using respiratory fluoroscopy and videofluoroscopic swallow studies

Aerodigestive diseases, hybrid disorders representing a pathologic link between respiratory and alimentary tracts, may manifest with respiratory signs without gastrointestinal signs. These are underdiagnosed in dogs due to poor clinical recognition and diagnostic limitations. We hypothesize that a subset of dogs presenting for cough without gastrointestinal signs would have occult aerodigestive disorders identified using videofluoroscopic swallow study (VFSS). Data were retrospectively obtained from 31 client-owned dogs presenting for cough, with thoracic radiographs, and a VFSS between April 2015 and December 2017. Exclusion criteria were cough of cardiac origin or gastrointestinal signs within 6 months. Swallow study parameters included pharyngeal/esophageal motility, laryngeal obstruction/defects, penetration-aspiration, reflux, excessive aerophagia, megaesophagus (ME), lower-esophageal sphincter achalasia-like syndrome (LES-AS), and sliding hiatal hernia (HH). The median (interquartile range) duration of cough was 4 (2-8) months. Thoracic radiographs were unremarkable in 11 dogs, with aspiration pneumonia suspected in seven. In 25/31 dogs (81%), VFSS abnormalities were detected and some dogs had more than one defect: pharyngeal (n=10) or esophageal hypomotility (n=10), reflux (n=9), penetration-aspiration (n=8), excessive aerophagia (n=6), laryngeal obstruction (n=3), ME (n=3), HH (n=2), and LES-AS (n=1). A respiratory disorder causing cough was identified in 17 dogs with VFSS abnormalities (laryngeal obstruction/defect and airway disease including chronic or eosinophilic bronchitis, tracheal/mainstem bronchial collapse, bronchiectasis, and bronchomalacia). An alimentary disorder identified on VFSS in absence of a discrete respiratory disorder causing cough was diagnosed in eight dogs. In conclusion, canine aerodigestive disorders can manifest as cough without alimentary signs. VFSS is a useful diagnostic to determine the contribution of esophageal/gastrointestinal pathology in dogs with cough.

The Lung Microbiome and Its Role in Pneumonia

The use of next-generation sequencing and multiomic analysis reveals new insights on the identity of microbes in the lower airways blurring the lines between commensals and pathogens. Microbes are not found in isolation; rather they form complex metacommunities where microbe-host and microbe-microbe interactions play important roles on the host susceptibility to pathogens. In addition, the lower airway microbiota exert significant effects on host immune tone. Thus, this review highlights the roles that microbes in the respiratory tract play in the development of pneumonia.

Profiling of lung microbiota in the patients with obstructive sleep apnea

Lung microbiota may affect innate immunity and treatment consequence in the obstructive sleep apnea (OSA) patients. Bronchoalveolar lavage fluid (BALF) was obtained from 11 OSA patients and 8 patients with other lung diseases as control, and used for lung microbiota profiling by PCR amplification and sequencing of the microbial samples. It was demonstrated that phyla of Firmicutes, Fusobacteria, and Bacteriodetes were relatively abundant in the lung microbiota. Alpha-diversity comparison between OSA and control group revealed that Proteobacteria and Fusobacteria were significantly higher in OSA patients (0.3863 ± 0.0631 and 0.0682 ± 0.0159, respectively) than that in control group (0.119 ± 0.074 and 0.0006 ± 0.0187, respectively, P < .05 for both phyla). In contrast, Firmicutes was significantly less in OSA patients (0.1371 ± 0.0394) compared with that in the control group (0.384 ± 0.046, P < .05). Comparison within a group (ß-diversity) indicated that the top 5 phyla in the OSA lung were Proteobacteria, Bacteroidetes, Firmicutes, Fusobacteria, and Acidobacteria, while the top 5 phyla in the control group were Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, and Acidobacteria. These findings indicated that lung microbiota in OSA is distinct from that of non-OSA patients. Manipulation of the microbiota may be an alternative strategy to augment airway immunity and to reduce susceptibility to airway infection.

Lung Microbiota and Its Impact on the Mucosal Immune Phenotype

The use of culture-independent techniques has allowed us to appreciate that the upper and lower respiratory tract contain a diverse community of microbes in health and disease. Research has only recently explored the effects of the microbiome on the host immune response. The exposure of the human body to the bacterial environment is an important factor for immunological development; thus, the interaction between the microbiome and its host is critical to understanding the pathogenesis of disease. In this article, we discuss the mechanisms that determine the composition of the airway microbiome and its effects on the host immune response. With the use of ecological principles, we have learned how the lower airways constitute a unique niche subjected to frequent microbial migration (e.g., through aspiration) and constant immunological pressure. The discussion will focus on the possible inflammatory pathways that are up- and downregulated when the immune system is challenged by dysbiosis. Identification of potential markers and microbial targets to address the modulation of inflammation in early disease, when changes may have the most effect, will be critical for future therapies.

Mechanism of Gastroesophageal Reflux in Obstructive Sleep Apnea: Airway Obstruction or Obesity?

STUDY OBJECTIVES

This is the first study to compare reflux events during wake and sleep in obese and non-obese individuals with obstructive sleep apnea (OSA) and obese individuals without OSA. The primary aim of the study was to investigate any additive effect of OSA on gastroesophageal reflux (GER) above that of obesity.

METHODS

Twenty obese individuals (body mass index, BMI > 30 kg/m(2)), 9 non-obese individuals (BMI < 30 kg/m(2)) with moderate-to-severe OSA, and 17 obese control subjects (BMI > 30 kg/m(2)) underwent high-resolution esophageal manometry, 24-h esophageal pH-impedance monitoring, and in-laboratory polysomnography.

RESULTS

Mean body mass index was 40 ± 6 and 27 ± 4 kg/m(2) for the obese and non-obese OSA groups, respectively, and 34 ± 5 kg/m(2) for the obese control group. Apnea-hypopnea index (AHI) was 50 ± 30 and 30 ± 25 per hour for the obese and non-obese OSA groups (p > 0.05), significantly higher than that of the obese control group (3 ± 3 per hour, p < 0.05). The two obese groups did not show any significant differences in the total number of acidic reflux events (41 ± 20 vs 28 ± 16); however, the obese OSA group had a greater number of acidic reflux events compared to the non-obese OSA group (22 ± 12 events, p < 0.05). In multivariate analysis, BMI significantly predicted number of acidic reflux events (r(2) = 0.16, p = 0.01) during the 24-h period; however, AHI showed no significant association with any measure of GER severity.

CONCLUSIONS

This study confirms an important role for obesity, rather than OSA per se in the relationship between OSA and GER.

Enrichment of the lung microbiome with oral taxa is associated with lung inflammation of a Th17 phenotype

Microaspiration is a common phenomenon in healthy subjects, but its frequency is increased in chronic inflammatory airway diseases, and its role in inflammatory and immune phenotypes is unclear. We have previously demonstrated that acellular bronchoalveolar lavage samples from half of the healthy people examined are enriched with oral taxa (here called pneumotypeSPT) and this finding is associated with increased numbers of lymphocytes and neutrophils in bronchoalveolar lavage. Here, we have characterized the inflammatory phenotype using a multi-omic approach. By evaluating both upper airway and acellular bronchoalveolar lavage samples from 49 subjects from three cohorts without known pulmonary disease, we observed that pneumotypeSPT was associated with a distinct metabolic profile, enhanced expression of inflammatory cytokines, a pro-inflammatory phenotype characterized by elevated Th-17 lymphocytes and, conversely, a blunted alveolar macrophage TLR4 response. The cellular immune responses observed in the lower airways of humans with pneumotypeSPT indicate a role for the aspiration-derived microbiota in regulating the basal inflammatory status at the pulmonary mucosal surface.

Lung microbiome for clinicians. New discoveries about bugs in healthy and diseased lungs

Microbes are readily cultured from epithelial surfaces of the skin, mouth, and colon. In the last 10 years, culture-independent DNA-based techniques demonstrated that much more complex microbial communities reside on most epithelial surfaces; this includes the lower airways, where bacterial culture had failed to reliably demonstrate resident bacteria. Exposure to a diverse bacterial environment is important for adequate immunological development. The most common microbes found in the lower airways are also found in the upper airways. Increasing abundance of oral characteristic taxa is associated with increased inflammatory cells and exhaled nitric oxide, suggesting that the airway microbiome induces an immunological response in the lung. Furthermore, rhinovirus infection leads to outgrowth of Haemophilus in patients with chronic obstructive pulmonary disease, and human immunodeficiency virus-infected subjects have more Tropheryma whipplei in the lower airway, suggesting a bidirectional interaction in which the host immune defenses also influence the microbial niche. Quantitative and/or qualitative changes in the lung microbiome may be relevant for disease progression and exacerbations in a number of pulmonary diseases. Future investigations with longitudinal follow-up to understand the dynamics of the lung microbiome may lead to the development of new therapeutic targets.

[Association between sleep quality and life function among elderly community residents]

OBJECTIVE

To investigate the association between sleep quality and life function in an elderly Japanese population.

METHODS

A total of 563 residents of a village in Kumamoto Prefecture aged ≥65 years were asked to fill out a self-administered questionnaire survey from June to July 2010. Sleep quality and life function were respectively evaluated using the Pittsburgh Sleep Quality Index (PSQI) and Basics Check List, which is used to screen elderly individuals at high risk of needing long-term care in the future. As adjustment factors, age, sex, economic situation, residency status, medical history, depression status, and cognitive function were assessed. We examined the relationship between sleep quality and life function using multiple logistic regression analysis, with life function as a dependent variable. Subjects already receiving care or with psychiatric disorders or severe cognitive disturbance were excluded from analysis.

RESULTS

Among the subjects (n=395), a significant relationship was found between poor sleep quality and impaired life function in all models. The odds ratio was 1.82 (95% confidence interval: 1.03-3.23) in the final model controlling for all adjustment factors.

CONCLUSIONS

Our findings here suggest a significant relationship between poor sleep quality and impaired life function among elderly community residents. Given these findings, intervention to improve sleep may help delay or prevent the need for long-term care among elderly individuals.

Mechanism of gastroesophageal reflux in patients with obstructive sleep apnea syndrome

BACKGROUND

It has been reported that the prevalence of gastroesophageal reflux (GER) disease is high in patients with obstructive sleep apnea (OSA). End-inspiratory intra-esophageal pressure decreases progressively during OSA, which has been thought to facilitate GER in OSA patients. The aim of our study was to clarify the mechanisms of GER during sleep (sleep-GER) in OSA patients.

METHODS

Eight OSA patients with reflux esophagitis (RE), nine OSA patients without RE, and eight healthy controls were studied. Polysomnography with concurrent esophageal manometry and pH recording were performed.

KEY RESULTS

Significantly more sleep-GER occurred in OSA patients with RE than without RE or in controls (P < 0.05). The severity of OSA did not differ between OSA patients with RE and without RE. Sleep-GER was mainly caused by transient lower esophageal sphincter relaxation (TLESR), but not by negative intra-esophageal pressure during OSA. During OSA gastroesophageal junction pressure progressively increased synchronous to intra-esophageal pressure decrease. OSA patients had significantly more TLESR events during sleep related to preceding arousals and shallow sleep, but the number of TLESR events was not related to RE.

CONCLUSIONS & INFERENCES

In OSA patients, sleep-GER was mainly caused by TLESR, but not by negative intra-esophageal pressure due to OSA.

The Montreal definition and classification of gastroesophageal reflux disease: a global evidence-based consensus

OBJECTIVES

A globally acceptable definition and classification of gastroesophageal reflux disease (GERD) is desirable for research and clinical practice. The aim of this initiative was to develop a consensus definition and classification that would be useful for patients, physicians, and regulatory agencies.

METHODS

A modified Delphi process was employed to reach consensus using repeated iterative voting. A series of statements was developed by a working group of five experts after a systematic review of the literature in three databases (Embase, Cochrane trials register, Medline). Over a period of 2 yr, the statements were developed, modified, and approved through four rounds of voting. The voting group consisted of 44 experts from 18 countries. The final vote was conducted on a 6-point scale and consensus was defined a priori as agreement by two-thirds of the participants.

RESULTS

The level of agreement strengthened throughout the process with two-thirds of the participants agreeing with 86%, 88%, 94%, and 100% of statements at each vote, respectively. At the final vote, 94% of the final 51 statements were approved by 90% of the Consensus Group, and 90% of statements were accepted with strong agreement or minor reservation. GERD was defined as a condition that develops when the reflux of stomach contents causes troublesome symptoms and/or complications. The disease was subclassified into esophageal and extraesophageal syndromes. Novel aspects of the new definition include a patient-centered approach that is independent of endoscopic findings, subclassification of the disease into discrete syndromes, and the recognition of laryngitis, cough, asthma, and dental erosions as possible GERD syndromes. It also proposes a new definition for suspected and proven Barrett's esophagus.

CONCLUSIONS

Evidence-based global consensus definitions are possible despite differences in terminology and language, prevalence, and manifestations of the disease in different countries. A global consensus definition for GERD may simplify disease management, allow collaborative research, and make studies more generalizable, assisting patients, physicians, and regulatory agencies.

Physiological and pathophysiological down-regulation of cough

Recent clinical studies have emphasized the up-regulation (sensitization) of cough in pathological conditions of the airways. However there are also many situations where voluntary and reflex cough can be down-regulated. These include: (1) chemical stimulation of breathing by hypercapnia or hypoxia or both, establishing that cough sensitivity can be inversely related to drive to breathing; (2) voluntary inhibition of cough, probably similar in mechanism to the depression of cough that can be induced by hypnosis and other branches of alternative medicine; (3) the placebo effect of many antitussive treatments; (4) sleep; (5) general anaesthesia; (6) central nervous disorders such as coma, stroke, Parkinson's disease and several other conditions where the defect in the protective reflexes may lead to aspiration pneumonia; (7) increased activity in various afferent inputs from viscera in the thorax and abdomen; (8) a number of bronchopulmonary clinical disorders. The list is long, but regrettably the nervous mechanisms of these down-regulations have been little studied. In addition there are a number of situations, such as exercise, coitus, talking and singing which, while important to coughing humans, have been not investigated in relation to cough. Most of the studies have been with experimental animals, and their extension to human research is desirable. In view of the importance of cough and other defensive reflexes in maintaining human well-being, far more research is needed. The field is wide-open.

Symptoms of gastro-oesophageal reflux disease and the severity of obstructive sleep apnoea syndrome are not related in sleep disorders center patients

BACKGROUND

Studies suggest obstructive sleep apnea syndrome (OSAS) frequently manifests in patients with gastroesophageal reflux disease (GERD) and that there may be a causal relationship.

AIM

To determine the relationship between OSAS and symptoms of GERD.

METHODS

Consecutive patients referred to the Sleep Disorders Center (SDC) 18 years and older with polysomnographically defined OSAS were evaluated prospectively for GERD using a validated symptoms questionnaire. The GERD and OSAS relationship was assessed by 1) determining frequency of GERD in patients with and without OSAS; 2) ascertaining the relationship between OSAS severity categories and presence of GERD; 3) examining GERD score in relation to those factors that might affect both GERD and OSAS, e.g. obesity.

RESULTS

One thousand and twenty-three SDC patients met entry criteria. Amongst participants, GERD was common (29% of women and 17% of males) and OSAS extremely common (58% of women and 80% of males). GERD score did not correlate with OSAS variables. The severity of OSAS did not influence the prevalence of GERD.

CONCLUSION

In a large group of patients referred to a sleep disorders center, there was no relationship between OSAS and GERD symptoms. Also, there was no relationship between the severity of OSAS and the likelihood of GERD symptoms.

Correlation between severity of endoscopic findings and apnea-hypopnea index in patients with gastroesophageal reflux disease and obstructive sleep apnea

AIM: To assess the relationship between severity of gastroesophageal reflux disease and apnea-hypopnea index (AHI) as an indicator of the severity of obstructive sleep apnea.

METHODS: Data of 57 patients with proven obstructive sleep apnea and gastroesophageal reflux disease were analyzed. Patients were divided into two groups according to severity of the sleep apnea: “mild-moderate” (A)-AHI ≥5-30, n = 27, “severe”(B)-AHI >30, n = 30. All patients underwent apnea monitoring during the night, upper panendoscopy and were asked about typical reflux symptoms.

RESULTS: All examined patients in both groups showed a significant overweight and there was a positive correlation between body mass index and the degree of sleep apnea (P = 0.0002). The occurence of erosive reflux disease was significantly higher in “severe” group (P = 0.0001). Using a logistic regression analysis a positive correlation was found between the endoscopic severity of reflux disease and the AHI (P = 0.016). Forty-nine point five percent of the patients experienced the typical symptoms of reflux disease at least three times a week and there was no significant difference between the two groups.

CONCLUSION: A positive correlation can be found between the severity of gastroesophageal reflux disease and obstructive sleep apnea.

Pantoprazole for Sleepiness Associated with Acid Reflux and Obstructive Sleep Disordered Breathing

OBJECTIVE

To determine the effectiveness of Pantoprazole (Wyeth Pharmaceuticals Inc., Philadelphia, PA) therapy for daytime sleepiness in patients with symptoms of acid reflux and obstructive sleep-disordered breathing (OSDB).

STUDY DESIGN

Prospective interventional cohort study.

METHODS

Twenty-seven adult subjects (67% men) with symptoms of acid reflux disease and mild to moderate OSDB were included in a 3-month study of proton pump inhibitor therapy (Pantoprazole 40 mg once daily). Primary outcomes included changes in daytime sleepiness, reflux symptoms, and bed partner assessment of snoring. Secondary outcomes included changes in snoring quantification, apnea, and apnea-hypopnea indices (AHI) with SNAP Laboratories (Glenview, IL) home sleep study and self-reported global symptom improvement.

RESULTS

At baseline, patients were typically middle-aged, obese men with mild to moderate sleep apnea (mean AHI = 15) with excessive daytime somnolence (mean Epworth Sleepiness Score = 13). After 3-month treatment with Pantoprazole, a statistically significant improvement was noted for daytime sleepiness (P = .002) and total reflux symptoms (P = .0006). Subjects also reported a significant reduction in reflux awakening them from sleep (P < .0001). Bed-partner assessment of snoring significantly improved (P = .03); however, no significant improvements were noted in snoring quantification, apnea, or AHI. When compared with a disease-severity matched historic placebo-control group, this cohort demonstrated a significantly greater reduction in daytime sleepiness (P = .04).

CONCLUSIONS

This cohort of subjects had significant improvements in daytime sleepiness and reflux symptoms, including reflux awakening from sleep, with Pantoprazole therapy. Further controlled studies are indicated to confirm these results. Improvement in daytime somnolence likely resulted from a reduction in reflux-related arousals because no improvements occurred in OSDB.

Is there a relationship between obstructive sleep apnea and gastroesophageal reflux disease?

BACKGROUND AND AIMS

The causative relationship between obstructive sleep apnea (OSA) and gastroesophageal reflux disease (GERD) remains an area of controversy. The aim of the study is to further explore the relationship between OSA and GERD in a large group of patients with OSA.

METHODS

One hundred thirty-six patients referred for polysomnographic studies at the University of Arizona Sleep Center were included in this study. All patients were assessed by means of a demographic survey, the validated GERD Symptom Checklist, and the Sleep Heart Health Study Sleep Habits Questionnaire. Polysomnograms were scored for objective measures of sleep and breathing. OSA is defined as an apnea-hypopnea index > 5 with compatible symptoms.

RESULTS

Of the 136 subjects, 101 (74%) were found to have OSA. Self-report of heartburn or acid regurgitation symptoms was unrelated to severity of sleep apnea. Additionally, OSA was not influenced by the severity of GERD. Objective measures of disordered sleep had stronger associations with age, smoking, and alcohol use than GERD in men and stronger associations with age and body mass index than GERD in women. Subjectively reported sleep quality was affected more strongly by GERD severity than by age, smoking, alcohol use, or the presence of OSA. Only females administered antireflux medications were less likely to report poor sleep quality.

CONCLUSIONS

Subjective reports of sleep quality were affected by GERD severity, but an objective correlation between OSA and GERD was lacking. This may suggest that GERD and OSA are common entities that share similar risk factors, but appear not to be causally linked.

Acidification of Distal Esophagus and Sleep-Related Breathing Disturbances

STUDY OBJECTIVES

To investigate whether distal esophageal acidification occurs during sleep in patients suspected of sleep-disordered breathing, and whether such acidification is related to respiratory abnormalities.

DESIGN AND PATIENTS

Fourteen middle-aged, snoring men all complaining of daytime sleepiness and suspected of having obstructive sleep apnea.

SETTING

Sleep laboratory, Pulmonary Department, Landspitali University Hospital, Reykjavik, Iceland.

MEASUREMENTS AND RESULTS

Each patient underwent full nocturnal polysomnography testing, which included continuous monitoring of esophageal pressure (Pes) and pH. We identified all pH events, which were defined as a reduction in esophageal pH of >/= 1.0. During each pH event, the respiratory recordings where examined for the presence of apneas or hypopneas, and Pes was recorded. The data were analyzed to determine the possible relationships between pH events and respiratory events, and between changes in pH and changes in Pes. We found that there were more respiratory events than pH events. The mean (+/- SD) number of apneas and hypopneas per hour of sleep was 33 +/- 22, whereas the mean number of pH events per hour of sleep was 7 +/- 6. Overall, 81% of all pH events were associated with respiratory events. Correlation analysis did not reveal any significant relationship between pH events and the magnitude of Pes or apnea-hypopnea index.

CONCLUSIONS

Episodes of esophageal acidification are common in patients with sleep apnea, and are usually associated with respiratory and pressure events. However, changes in pH were independent of the magnitude of the Pes.

Variables affecting the occurrence of gastroesophageal reflux in obstructive sleep apnea patients

A number of recent studies have suggested that apnea and/or hypopnea episodes may be in a causal relationship with nocturnal gastroesophageal reflux (GER) episodes in obstructive sleep apnea (OSA) patients. In this study, we addressed the possible factors that may affect the occurrence of reflux events in OSA patients. For this reason, we investigated respiratory and sleep parameters in OSA patients with or without nocturnal GER episodes. Nineteen patients who were referred to the sleep laboratory for suspected sleep apnea were included in the study. All subjects underwent polysomnographic evaluation simultaneously with distal and proximal esophageal pH monitoring. During the recording period, a total of 134 reflux events, 134 from distal probes and none from proximal probes, were recorded. We divided patients into two groups: (1) nocturnal GER-positive patients ( n=8; age: 41.9+/-11.9) and (2) nocturnal GER-negative patients ( n=11; age: 45.4+/-3.3). We compared demographic, respiratory and sleep parameters between the two groups. Then we analysed the time relation between GER episodes and obstructive respiratory events. The two groups were matched by age and body mass index. Sleep and respiratory parameters were not different between the two groups. In conclusion, we suggested that age, body mass index and the severity of disease in obstructive sleep apnea patients are not effective determinants of gastroesophageal reflux. There is no sufficient evidence to accept arousals and obstructive apneas as primary causes of gastroesophageal reflux and vice versa. And finally, sleep macroorganisation has no impact on the occurrence of GER in OSAS.