Role of hydrogen and methane breath testing in gastrointestinal diseases

[Methanobrevibacter smithii in irritable bowel syndrome: a clinical and molecular study]

AIM

To assess the role of Methanobrevibacter smithii in patients with irritable bowel syndrome associated with small intestinal bowel overgrowth.

MATERIALS AND METHODS

Sixty - seven patients with IBS according to Rome IV were enrolled into the study in whom hydrogen breath test was performed. Thirty - two healthy subjects with negative breath test was used as a control. All IBS symptoms assessed daily with 5 grade Lykert scale for 7 days, stool was assessed by Brystol stool scale. M. smithii was confirmed in stool samples by PCR.

RESULTS AND DISCUSSION

In 67 IBS patients CH4 overproduction was found in 32 (47.7%), H2 overproduction in 31 (46.2%) and normal values in 4 (5.9%) by hydrogen breath test. M. smithii was confirmed by stool PCR in all patients with CH4 overproduction. Severity and prevalence of main clinical features of IBS were similar in both SIBO groups but were significantly higher than in control (p.

Long-term monitoring of breath methane

In recent years, methane as a component of exhaled human breath has been considered as a potential bioindicator providing information on microbial activity in the intestinal tract. Several studies indicated a relationship between breath methane status and specific gastrointestinal disease. So far, almost no attention has been given to the temporal variability of breath methane production by individual persons. Thus here, for the first time, long-term monitoring was carried out measuring breath methane of three volunteers over periods between 196 and 1002days. Results were evaluated taking into consideration the health status and specific medical intervention events for each individual during the monitoring period, and included a gastroscopy procedure, a vaccination, a dietary change, and chelate therapy. As a major outcome, breath methane mixing ratios show considerable variability within a person-specific range of values. Interestingly, decreased breath methane production often coincided with gastrointestinal complaints whereas influenza infections were mostly accompanied by increased breath methane production. A gastroscopic examination as well as a change to a low-fructose diet led to a dramatic shift of methane mixing ratios from high to low methane production. In contrast, a typhus vaccination as well as single chelate injections resulted in significant short-term methane peaks. Thus, this study clearly shows that humans can change from high to low methane emitters and vice versa within relatively short time periods. In the case of low to medium methane emitters the increase observed in methane mixing ratios, likely resulting from immune reactions and inflammatory processes, might indicate non-microbial methane formation under aerobic conditions. Although detailed reaction pathways are not yet known, aerobic methane formation might be related to cellular oxidative-reductive stress reactions. However, a detailed understanding of the pathways involved in human methane formation is necessary to enable comprehensive interpretation of methane breath levels.

Medical applications of breath hydrogen measurements

In this article, technical developments in breath analysis and its applications in the field of clinical diagnosis and the monitoring of various symptoms, particularly molecular hydrogen in breath, are introduced. First, a brief overview of the current uses of the hydrogen breath test is provided. The principles of the test and how hydrogen can be used as a biomarker for various symptoms, and monitoring microbial metabolism, are introduced. Ten case-study applications of breath hydrogen measurements for which hydrogen exhibits beneficial effects for diagnosis, including the contexts of oxidative stress, gastrointestinal disease, and metabolic disorders, are discussed. The technologies and problems involved in breath hydrogen testing, sampling, pretreatment, and detection in exhaled breath are discussed, and research including current analytical systems and new sensors is focused on in the context of hydrogen detection.