Research Gaps in Diet and Nutrition in Inflammatory Bowel Disease. A Topical Review by D-ECCO Working Group [Dietitians of ECCO]

Although the current doctrine of IBD pathogenesis proposes an interaction between environmental factors and gut microbiota in genetically susceptible individuals, dietary exposures have attracted recent interest and are, at least in part, likely to explain the rapid rise in disease incidence and prevalence. The D-ECCO working group along with other ECCO experts with expertise in nutrition, microbiology, physiology, and medicine reviewed the evidence investigating the role of diet and nutritional therapy in the onset, perpetuation, and management of IBD. A narrative topical review is presented where evidence pertinent to the topic is summarised collectively under three main thematic domains: i] the role of diet as an environmental factor in IBD aetiology; ii] the role of diet as induction and maintenance therapy in IBD; and iii] assessment of nutritional status and supportive nutritional therapy in IBD. A summary of research gaps for each of these thematic domains is proposed, which is anticipated to be agenda-setting for future research in the area of diet and nutrition in IBD.

European Crohn's and Colitis Organisation Topical Review on Environmental Factors in IBD

This ECCO Topical Review of the European Crohn's and Colitis Organisation [ECCO] focuses on the role of environmental factors with respect to the development of inflammatory bowel disease [IBD] as well as their influence on the course of established IBD. The objective was to reach expert consensus to provide evidence-based guidance for clinical practice.

Mucosal impedance discriminates GERD from non-GERD conditions

BACKGROUND & AIMS

Current diagnostic tests for gastroesophageal reflux disease (GERD) are suboptimal and do not accurately and reliably measure chronicity of reflux. A minimally invasive device has been developed to assess esophageal mucosal impedance (MI) as a marker of chronic reflux. We performed a prospective longitudinal study to investigate MI patterns in patients with GERD and common nonreflux conditions, to assess MI patterns before and after treatment with proton pump inhibitors and to compare the performance of MI and wireless pH tests.

METHODS

We evaluated MI in 61 patients with erosive esophagitis, 81 with nonerosive but pH-abnormal GERD, 93 without GERD, 18 with achalasia, and 15 with eosinophilic esophagitis. MI was measured at the site of esophagitis and at 2, 5, and 10 cm above the squamocolumnar junction in all participants. MI was measured before and after acid suppressive therapy, and findings were compared with those from wireless pH monitoring.

RESULTS

MI values were significantly lower in patients with GERD (erosive esophagitis or nonerosive but pH-abnormal GERD) or eosinophilic esophagitis than in patients without GERD or patients with achalasia (P < .001). The pattern of MI in patients with GERD differed from that in patients without GERD or patients with eosinophilic esophagitis; patients with GERD had low MI closer to the squamocolumnar junction, and values increased axially along the esophagus. These patterns normalized with acid suppressive therapy. MI patterns identified patients with esophagitis with higher levels of specificity (95%) and positive predictive values (96%) than wireless pH monitoring (64% and 40%, respectively).

CONCLUSIONS

Based on a prospective study using a prototype device, measurements of MI detect GERD with higher levels of specificity and positive predictive values than wireless pH monitoring. Clinical Trials.gov, Number: NCT01556919.

The role of impedance monitoring in patients with extraesophageal symptoms

OBJECTIVES/HYPOTHESIS

Ambulatory esophageal impedance monitoring is commonly employed to assess for nonacid reflux in patients with extraesophageal reflux. We aimed to determine if on therapy impedance data can be predicted from off therapy upper endoscopy, manometry, or pH parameters.

STUDY DESIGN

Prospective Cohort Study.

METHODS

Patients with extraesophageal reflux symptoms and either partial- or nonresponders to twice-daily PPI underwent impedance monitoring on twice-daily PPI, as well as manometry, upper endoscopy, and 48-hour wireless pH monitoring off acid-suppressive medications for 1 week. Percent time pH < 4 and number of reflux episodes were obtained. Multivariable linear regression was used to determine association between the impedance data on therapy and upper endoscopy, manometry, and pH parameters measured off therapy.

RESULTS

Seventy-five patients (77% female, median BMI 29, 38% with hiatal hernia, and 19% with esophagitis) were studied both on and off therapy. Thirty-five percent had abnormal impedance monitoring on therapy and 84% had abnormal pH testing off therapy. There was no significant (P = 0.184) overall correlation between total number of impedance events and the baseline physiologic parameters of hiatal hernia, degree of acid reflux, or manometric findings, with only weak correlation (r = 0.54, P = 0.045) with % time pH < 4 among patients with esophagitis.

CONCLUSIONS

In patients with suspected extraesophageal reflux refractory to PPI therapy, impedance measures on therapy cannot be predicted from traditional baseline esophageal physiologic parameters. We recommend caution regarding over-interpretation of impedance data.

LEVEL OF EVIDENCE

2b.

An oropharyngeal pH monitoring device to evaluate patients with chronic laryngitis

BACKGROUND

Diagnostics for gastro-esophageal reflux disease (GERD) are suboptimal because of limited sensitivity. We performed in vitro and in vivo studies to systematically assess the performance characteristics of an oropharyngeal pH probe.

METHODS

In vitro studies compared the oropharyngeal probe with a standard pH catheter in liquid and aerosolized solutions, pH 1-7. The accuracy of measurements, deviation from target pH, and time to equilibrium pH were determined. Simultaneous distal esophageal pH measurements were obtained in 11 patients with GERD. Oropharyngeal and distal esophageal reflux parameters were measured for controls (n = 20), patients with GERD (n = 17), and patients with chronic laryngitis (n = 10).

KEY RESULTS

In the liquid phase, at pH 4-5, the oropharyngeal probe had less deviation from the target value than the standard catheter; deviation in the vapor phase was similar (0.4 pH units). Median (interquartile) time to reach equilibrium pH was significantly (P < 0.001) faster with the oropharyngeal than the standard probe. In comparing simultaneous distal esophageal pH characteristics, 96% of recordings with the new and standard probes were in agreement to within ± 1.0 pH unit; 71% of recordings were in agreement within ± 0.5 pH units. Patients with chronic laryngitis had significantly higher levels of oropharyngeal acid exposure at pH <4, <5, and <6, in the upright position than patients with GERD or controls (P < .001).

CONCLUSIONS & INFERENCES

Oropharyngeal pH monitoring appears to be more sensitive than traditional pH monitoring in evaluation of patients with extraesophageal reflux. It is a promising tool in evaluation of this difficult group of patients.

Use of direct, endoscopic-guided measurements of mucosal impedance in diagnosis of gastroesophageal reflux disease

BACKGROUND & AIMS

Diagnostic tests for gastroesophageal reflux disease (GERD) are constrained because measurements are made at a single time point, so the long-term effects on the mucosa cannot be determined. We developed a minimally invasive system to assess changes in esophageal mucosal impedance (MI), a marker of reflux. We measured the extent of changes in MI along the esophagus and show that the device to assess MI can be used to diagnose patients with GERD.

METHODS

A single-channel MI catheter composed of a unique sensor array was designed to easily traverse the working channel of an upper endoscope. We performed a prospective longitudinal study of patients with erosive esophagitis (n = 19), nonerosive but pH-positive GERD (n = 23), and those without GERD (n = 27). MI was measured at the site of esophagitis as well as 2, 5, and 10 cm above the squamocolumnar junction. The MI values were compared among groups, at different levels along the esophageal axis.

RESULTS

Median MI values were significantly lower at the site of erosive mucosa (811 Ω; range, 621-1272 Ω) than other nonerosive regions (3723 Ω; range, 2421-4671 Ω; P = .001), and were significantly lower at 2 cm above the squamocolumnar junction in patients with GERD (2096 Ω; range, 1415-2808 Ω), compared with those without GERD (3607 Ω; range, 1973-4238 Ω; P = .008). There was a significant and graded increase in MI along the axis of the distal to proximal esophagus in patients with GERD that was not observed in individuals without reflux (P = .004).

CONCLUSIONS

Measurements of MI along the esophagus can be used to identify patients with GERD. ClinicalTrials.gov, number NCT01194323.

New developments in extraesophageal reflux disease

Gastroesophageal reflux disease (GERD) can present with a wide variety of extraesophageal symptoms that are usually difficult to diagnose because of the absence of typical GERD symptoms (ie, regurgitation or heartburn). The diagnostic process is further complicated by the lack of a definitive test for identifying GERD as the cause of extraesophageal reflux symptoms. Due to the low predictive value of upper endoscopy and pH testing-as well as the lack of reliability of the symptom index and symptom association probability-extraesophageal reflux disease is still an area of investigation. This paper discusses recent developments in this field, with special emphasis on new diagnostic modalities and treatment options.

Aurora kinase A (AURKA) and never in mitosis gene A-related kinase 6 (NEK6) genes are upregulated in erosive esophagitis and esophageal adenocarcinoma

Gastroesophageal reflux disease is a risk factor for esophageal adenocarcinoma yet studies that have investigated the relationship between erosive esophagitis and esophageal adenocarcinoma have usually focused on symptom-related evidence or polymorphisms. There are no epigenetic gene expression studies on this topic. In this study, we aimed to evaluate the relationship between erosive esophagitis and esophageal adenocarcinoma to identify whether there is a genetic predisposition for esophageal adenocarcinoma. The Human Epigenetic Chromatin Modification Enzyme RT(2) Profiler(™) PCR array (PAHS-085A) was used to detect the expression of 84 key genes encoding enzymes. This was carried out prospectively for samples from 60 patients (20 patients as a control group, 20 patients with erosive esophagitis and 20 patients with esophageal adenocarcinoma). AURKA, AURKB, NEK6 were expressed at significantly higher levels in esophageal adenocarcinoma compared to the control group. MBD2 was expressed at significantly lower levels in the esophageal adenocarcinoma group compared to the control group. AURKA, AURKC, HDAC9 and NEK6 were expressed at significantly higher levels in erosive esophagitis compared to the control group. There was no difference in upregulated gene expression between the erosive esophagitis and esophageal adenocarcinoma. MBD2 was significantly downregulated in esophageal adenocarcinoma compared to erosive esophagitis. NEK6 and AURKA were significantly upregulated in esophageal adenocarcinoma and erosive esophagitis compared to the control group. This is a novel study on the genetic predisposition for erosive esophagitis and esophageal adenocarcinoma. AURKA and NEK6 are two promising genetic markers for erosive esophagitis and esophageal adenocarcinoma.

Rapid salivary pepsin test: blinded assessment of test performance in gastroesophageal reflux disease

OBJECTIVE/HYPOTHESIS

Pepsin lateral flow device (LFD) is a rapid noninvasive test to detect salivary pepsin as a surrogate marker for gastroesophageal reflux disease (GERD). We aimed to establish the test sensitivity, specificity, positive and negative predictive values (PPV, NPV) in patients with symptomatic and objective evidence of GERD compared to healthy controls.

STUDY DESIGN

Prospective, blinded, controlled cohort study.

METHODS

A total of 230 samples were analyzed. In vitro bench testing was conducted on 52 gastric juice and 54 sterile water samples to assess test sensitivity and specificity. Saliva was collected from 58 patients with GERD and 51 controls. All patients with GERD underwent esophagogastroduodenoscopy (EGD) and wireless 48-hour pH monitoring off acid suppressive therapy. PPV and NPV were calculated based on disease definition of esophagitis and/or abnormal pH monitoring.

RESULTS

Receiver operating characteristics analysis of in vitro samples found assay sensitivity and a specificity of 87%. There were 6/51 (12%) control subjects and 13/58 (22%) patients with GERD who tested positive for salivary pepsin (P = .25). There was a step-wise increase in the prevalence of positive salivary pepsin: esophagitis (55%), abnormal pH monitoring (43%), GERD symptoms only (24%) (P < .001). Salivary pepsin test showed a PPV of 81% and NPV of 78% for those with objective evidence of GERD (abnormal pH and/or esophagitis).

CONCLUSIONS

Rapid LFD for salivary pepsin has acceptable test characteristics in patients with GERD. A positive salivary pepsin test in this group may obviate the need for more expensive diagnostic testing by EGD or pH monitoring.

Extraesophageal manifestations of gastroesophageal reflux disease: cough, asthma, laryngitis, chest pain

GER is a common condition affecting many patients in different parts of the world. It usually presents with the classic manifestations of heartburn and regurgitation; however, in some it can also present with extraesophageal manifestations such as chronic cough, laryngitis, asthma or chest pain. Commonly employed diagnostic tests such as EGD and ambulatory pH or impedance monitoring in GER, are less useful in extraesophageal syndromes due to their poor sensitivity and specificity. In contrast, empiric trials of PPI's are shown to be cost effective; however, patients may require long-term treatment to establish effectiveness. Diagnostic testing with pH and impedance monitoring are commonly reserved for patients with partial or poor response to the initial treatment with PPI's. Poor response to PPI therapy may be an important indicator for non-GER causes for patients' symptoms and should initiate a search for other potential causes.