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3ВОДНЫЕ РАСТВОРЫ В БИОЛОГИЧЕСКИХ СИСТЕМАХ
HYDROGEN AND METHANE-RICH WATER AS DIAGNOSTIC TOOL FOR NON-INVASIVE ANALYSIS OF ITS KINETICS IN THE HUMANS AND LABORATORY ANIMALS
Medvedev O.S.1, Shirokov I.V.1, Ponurovskii Ya.Ya. 2, Stavrovskii D.B. 2, Karabinenko A.A. 3
1LomonosovMoscow State University, Russia, 119192, Moscow, 27-1 Lomonosovsky Prospekt 2Prokhorov General Physics Institute of the Russian Academy of Sciences, Russia, 119991, Moscow, 38 Vavilov street 3Pirogov Russian National Research Medical University, Russia, 117997, Moscow, 1 Ostrovitianov street
oleg.omedvedev@gmail.com
Introduction. During several decades hydrogen/methane (H2/CH4)-breath tests were used in gastroenterology for analysis of fermentative activity of the gut microbiome. To perform such test non-digestible carbohydrate, usually water solution of lactulose (di-saccharide, containing fructose+galactose) is taken by the human as carbohydrate load. Lactulose in not absorbed in the small intestine and is metabolized by the mixture of microorganisms (microbiome) in the large intestine. Among several products of fermentation H2 and CH4 are produced and can serve as biomarkers of the intensity of fermentation [1]. General assumption is that H2 and CH4 biologically inert molecules and could be produced only by the bacteria, but not by the somatic cells of the mammal's organisms. So, the breath test is based on the periodic measurements of the H2 and CH4 concentrations (range 1-150 ppm) in exhaled air during 2-3 hours. In most labs gas chromatography (GC) is used for such measurements. The assumption is that concentrations of H2 and CH4 in the exhaled air reflect the levels of these gases in the place of its origin - the large intestine. Such assumption is not very precise as well as we do not know the amount of H2 and CH4 produced, effects of the intestinal wall, solubility in the blood of portal vein, possible saturation of liver tissue and parameters of respiration.
The turning point in the evaluation of breath test took place after the article of a group of Japanese scientists was published in Nature and showed that H2 could be an active antioxidant and be helpful in fighting the oxidative stress [2].
The aim of our study was to develop method to investigate the relationship between amount of H2 and CH4 consumed and dynamic of their appearance in exhaled air.
Methods. Water, saturated with H2 and CH4 was used to administer known amount of gases to be studied. Concentrations of O2, CO2, CH4, NH3, H2S were measured in exhaled air by the Tunable Diode Laser Spectrometer, (TDLS) developed in the GPI. Concentrations of H2 were measured by the GC (TriLyzer M3000, Japan). 2
Results. The baseline levels of H2 and CH4 was different in exhaled air of volunteers. The total amount of H2 and CH4 exhaled was 30-60% less, then the amount consumed that reflects the amount of -OH, neutralized by the H2.
Discussion. The main advantage of using TDLS system is opportunity to measure levels of many gases in real time, which allow the analysis of the gases kinetics. The results of our study show the differences in levels of exhaled air that depends on the bacterial contents of every individual and allow developing the personalized recommendations on the maintenance of health and treatment of the different diseases.
[1] О.С.Медведев, Роль водорода и метана микробиома человека и животных в обеспечении антиоксидантной защиты организма, Успехи современной биологии, 142 (4), 349-364 (2022).
[2] I.Ohsawa, M.Ishikawa, K.Takahashi et al., Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen
radicals, Nature Medicine, 13, 688-694 (2007).
