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Keppler F, Boros M, Polag D. Radical-Driven Methane Formation in Humans Evidenced by Exogenous Isotope-Labeled DMSO and Methionine. Antioxidants (Basel) 2023; 12:1381. [PMID: 37507920 PMCID: PMC10376501 DOI: 10.3390/antiox12071381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/29/2023] [Accepted: 07/01/2023] [Indexed: 07/30/2023] Open
Abstract
Methane (CH4), which is produced endogenously in animals and plants, was recently suggested to play a role in cellular physiology, potentially influencing the signaling pathways and regulatory mechanisms involved in nitrosative and oxidative stress responses. In addition, it was proposed that the supplementation of CH4 to organisms may be beneficial for the treatment of several diseases, including ischemia, reperfusion injury, and inflammation. However, it is still unclear whether and how CH4 is produced in mammalian cells without the help of microorganisms, and how CH4 might be involved in physiological processes in humans. In this study, we produced the first evidence of the principle that CH4 is formed non-microbially in the human body by applying isotopically labeled methylated sulfur compounds, such as dimethyl sulfoxide (DMSO) and methionine, as carbon precursors to confirm cellular CH4 formation. A volunteer applied isotopically labeled (2H and 13C) DMSO on the skin, orally, and to blood samples. The monitoring of stable isotope values of CH4 convincingly showed the conversion of the methyl groups, as isotopically labeled CH4 was formed during all experiments. Based on these results, we considered several hypotheses about endogenously formed CH4 in humans, including physiological aspects and stress responses involving reactive oxygen species (ROS). While further and broader validation studies are needed, the results may unambiguously serve as a proof of concept for the endogenous formation of CH4 in humans via a radical-driven process. Furthermore, these results might encourage follow-up studies to decipher the potential physiological role of CH4 and its bioactivity in humans in more detail. Of particular importance is the potential to monitor CH4 as an oxidative stress biomarker if the observed large variability of CH4 in breath air is an indicator of physiological stress responses and immune reactions. Finally, the potential role of DMSO as a radical scavenger to counteract oxidative stress caused by ROS might be considered in the health sciences. DMSO has already been investigated for many years, but its potential positive role in medical use remains highly uncertain.
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Affiliation(s)
- Frank Keppler
- Institute of Earth Sciences, Heidelberg University, D-69120 Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg University, D-69120 Heidelberg, Germany
| | - Mihály Boros
- Institute of Surgical Research, University of Szeged, H-6724 Szeged, Hungary
| | - Daniela Polag
- Institute of Earth Sciences, Heidelberg University, D-69120 Heidelberg, Germany
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2
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Jávor P, Donka T, Horváth T, Sándor L, Török L, Szabó A, Hartmann P. Impairment of Mesenteric Perfusion as a Marker of Major Bleeding in Trauma Patients. J Clin Med 2023; 12:jcm12103571. [PMID: 37240677 DOI: 10.3390/jcm12103571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/17/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
The majority of potentially preventable mortality in trauma patients is related to bleeding; therefore, early recognition and effective treatment of hemorrhagic shock impose a cardinal challenge for trauma teams worldwide. The reduction in mesenteric perfusion (MP) is among the first compensatory responses to blood loss; however, there is no adequate tool for splanchnic hemodynamic monitoring in emergency patient care. In this narrative review, (i) methods based on flowmetry, CT imaging, video microscopy (VM), measurement of laboratory markers, spectroscopy, and tissue capnometry were critically analyzed with respect to their accessibility, and applicability, sensitivity, and specificity. (ii) Then, we demonstrated that derangement of MP is a promising diagnostic indicator of blood loss. (iii) Finally, we discussed a new diagnostic method for the evaluation of hemorrhage based on exhaled methane (CH4) measurement. Conclusions: Monitoring the MP is a feasible option for the evaluation of blood loss. There are a wide range of experimentally used methodologies; however, due to their practical limitations, only a fraction of them could be integrated into routine emergency trauma care. According to our comprehensive review, breath analysis, including exhaled CH4 measurement, would provide the possibility for continuous, non-invasive monitoring of blood loss.
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Affiliation(s)
- Péter Jávor
- Department of Traumatology, University of Szeged, H-6725 Szeged, Hungary
| | - Tibor Donka
- Department of Traumatology, University of Szeged, H-6725 Szeged, Hungary
| | - Tamara Horváth
- Institute of Surgical Research, University of Szeged, H-6724 Szeged, Hungary
| | - Lilla Sándor
- Department of Traumatology, University of Szeged, H-6725 Szeged, Hungary
| | - László Török
- Department of Traumatology, University of Szeged, H-6725 Szeged, Hungary
- Department of Sports Medicine, University of Szeged, H-6725 Szeged, Hungary
| | - Andrea Szabó
- Institute of Surgical Research, University of Szeged, H-6724 Szeged, Hungary
| | - Petra Hartmann
- Department of Traumatology, University of Szeged, H-6725 Szeged, Hungary
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Tomasova L, Grman M, Ondrias K, Ufnal M. The impact of gut microbiota metabolites on cellular bioenergetics and cardiometabolic health. Nutr Metab (Lond) 2021; 18:72. [PMID: 34266472 PMCID: PMC8281717 DOI: 10.1186/s12986-021-00598-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 07/02/2021] [Indexed: 12/20/2022] Open
Abstract
Recent research demonstrates a reciprocal relationship between gut microbiota-derived metabolites and the host in controlling the energy homeostasis in mammals. On the one hand, to thrive, gut bacteria exploit nutrients digested by the host. On the other hand, the host utilizes numerous products of gut bacteria metabolism as a substrate for ATP production in the colon. Finally, bacterial metabolites seep from the gut into the bloodstream and interfere with the host’s cellular bioenergetics machinery. Notably, there is an association between alterations in microbiota composition and the development of metabolic diseases and their cardiovascular complications. Some metabolites, like short-chain fatty acids and trimethylamine, are considered markers of cardiometabolic health. Others, like hydrogen sulfide and nitrite, demonstrate antihypertensive properties. Scientific databases were searched for pre-clinical and clinical studies to summarize current knowledge on the role of gut microbiota metabolites in the regulation of mammalian bioenergetics and discuss their potential involvement in the development of cardiometabolic disorders. Overall, the available data demonstrates that gut bacteria products affect physiological and pathological processes controlling energy and vascular homeostasis. Thus, the modulation of microbiota-derived metabolites may represent a new approach for treating obesity, hypertension and type 2 diabetes.
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Affiliation(s)
- Lenka Tomasova
- Institute of Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05, Bratislava, Slovak Republic.
| | - Marian Grman
- Institute of Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05, Bratislava, Slovak Republic
| | - Karol Ondrias
- Institute of Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05, Bratislava, Slovak Republic
| | - Marcin Ufnal
- Department of Experimental Physiology and Pathophysiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, 02-091, Warsaw, Poland.
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Varga P, Vida N, Hartmann P, Szabó A, Mohácsi Á, Szabó G, Boros M, Tuboly E. Alternative methanogenesis - Methanogenic potential of organosulfur administration. PLoS One 2020; 15:e0236578. [PMID: 32730295 PMCID: PMC7392280 DOI: 10.1371/journal.pone.0236578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 07/08/2020] [Indexed: 11/23/2022] Open
Affiliation(s)
- Petra Varga
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Noémi Vida
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Petra Hartmann
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Anna Szabó
- MTA-SZTE Research Group on Photoacoustic Spectroscopy, University of Szeged, Szeged, Hungary
| | - Árpád Mohácsi
- MTA-SZTE Research Group on Photoacoustic Spectroscopy, University of Szeged, Szeged, Hungary
| | - Gábor Szabó
- MTA-SZTE Research Group on Photoacoustic Spectroscopy, University of Szeged, Szeged, Hungary
| | - Mihály Boros
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Eszter Tuboly
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
- * E-mail:
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Poles MZ, Juhász L, Boros M. Methane and Inflammation - A Review (Fight Fire with Fire). Intensive Care Med Exp 2019; 7:68. [PMID: 31807906 PMCID: PMC6895343 DOI: 10.1186/s40635-019-0278-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/24/2019] [Indexed: 12/23/2022] Open
Abstract
Mammalian methanogenesis is regarded as an indicator of carbohydrate fermentation by anaerobic gastrointestinal flora. Once generated by microbes or released by a non-bacterial process, methane is generally considered to be biologically inactive. However, recent studies have provided evidence for methane bioactivity in various in vivo settings. The administration of methane either in gas form or solutions has been shown to have anti-inflammatory and neuroprotective effects in an array of experimental conditions, such as ischemia/reperfusion, endotoxemia and sepsis. It has also been demonstrated that exogenous methane influences the key regulatory mechanisms and cellular signalling pathways involved in oxidative and nitrosative stress responses. This review offers an insight into the latest findings on the multi-faceted organ protective activity of exogenous methane treatments with special emphasis on its versatile effects demonstrated in sepsis models.
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Affiliation(s)
- Marietta Zita Poles
- Institute of Surgical Research, University of Szeged, Pulz u. 1., Szeged, H-6724, Hungary
| | - László Juhász
- Institute of Surgical Research, University of Szeged, Pulz u. 1., Szeged, H-6724, Hungary
| | - Mihály Boros
- Institute of Surgical Research, University of Szeged, Pulz u. 1., Szeged, H-6724, Hungary.
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Boros M, Keppler F. Methane Production and Bioactivity-A Link to Oxido-Reductive Stress. Front Physiol 2019; 10:1244. [PMID: 31611816 PMCID: PMC6776796 DOI: 10.3389/fphys.2019.01244] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 09/10/2019] [Indexed: 12/15/2022] Open
Abstract
Biological methane formation is associated with anoxic environments and the activity of anaerobic prokaryotes (Archaea). However, recent studies have confirmed methane release from eukaryotes, including plants, fungi, and animals, even in the absence of microbes and in the presence of oxygen. Furthermore, it was found that aerobic methane emission in plants is stimulated by a variety of environmental stress factors, leading to reactive oxygen species (ROS) generation. Further research presented evidence that molecules with sulfur and nitrogen bonded methyl groups such as methionine or choline are carbon precursors of aerobic methane formation. Once generated, methane is widely considered to be physiologically inert in eukaryotes, but several studies have found association between mammalian methanogenesis and gastrointestinal (GI) motility changes. In addition, a number of recent reports demonstrated anti-inflammatory potential for exogenous methane-based approaches in model anoxia-reoxygenation experiments. It has also been convincingly demonstrated that methane can influence the downstream effectors of transiently increased ROS levels, including mitochondria-related pro-apoptotic pathways during ischemia-reperfusion (IR) conditions. Besides, exogenous methane can modify the outcome of gasotransmitter-mediated events in plants, and it appears that similar mechanism might be active in mammals as well. This review summarizes the relevant literature on methane-producing processes in eukaryotes, and the available results that underscore its bioactivity. The current evidences suggest that methane liberation and biological effectiveness are both linked to cellular redox regulation. The data collectively imply that exogenous methane influences the regulatory mechanisms and signaling pathways involved in oxidative and nitrosative stress responses, which suggests a modulator role for methane in hypoxia-linked pathologies.
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Affiliation(s)
- Mihály Boros
- Institute of Surgical Research, Interdisciplinary Centre of Excellence, University of Szeged, Szeged, Hungary
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
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He Z, Ding R, Wu F, Wu Z, Liang C. Excess Alcohol Consumption: A Potential Mechanism Behind the Association Between Small Intestinal Bacterial Overgrowth and Coronary Artery Disease. Dig Dis Sci 2018; 63:3516-3517. [PMID: 30367306 DOI: 10.1007/s10620-018-5279-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/06/2018] [Indexed: 02/08/2023]
Affiliation(s)
- Zhiqing He
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415, Fengyang Road, Huangpu District, Shanghai, People's Republic of China
| | - Ru Ding
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415, Fengyang Road, Huangpu District, Shanghai, People's Republic of China
| | - Feng Wu
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415, Fengyang Road, Huangpu District, Shanghai, People's Republic of China
| | - Zonggui Wu
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415, Fengyang Road, Huangpu District, Shanghai, People's Republic of China
| | - Chun Liang
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, No. 415, Fengyang Road, Huangpu District, Shanghai, People's Republic of China.
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Polag D, Keppler F. Long-term monitoring of breath methane. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 624:69-77. [PMID: 29247906 DOI: 10.1016/j.scitotenv.2017.12.097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/08/2017] [Accepted: 12/08/2017] [Indexed: 06/07/2023]
Abstract
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.
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Affiliation(s)
- Daniela Polag
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany.
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany
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Mészáros AT, Szilágyi ÁL, Juhász L, Tuboly E, Érces D, Varga G, Hartmann P. Mitochondria As Sources and Targets of Methane. Front Med (Lausanne) 2017; 4:195. [PMID: 29181377 PMCID: PMC5693848 DOI: 10.3389/fmed.2017.00195] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/25/2017] [Indexed: 12/14/2022] Open
Abstract
This review summarizes the current knowledge on the role of mitochondria in the context of hypoxic cell biology, while providing evidence of how these mechanisms are modulated by methane (CH4). Recent studies have unambiguously confirmed CH4 bioactivity in various in vitro and in vivo experimental models and established the possibility that CH4 can affect many aspects of mitochondrial physiology. To date, no specific binding of CH4 to any enzymes or receptors have been reported, and it is probable that many of its effects are related to physico-chemical properties of the non-polar molecule. (i) Mitochondria themselves can be sources of endogenous CH4 generation under oxido-reductive stress conditions; chemical inhibition of the mitochondrial electron transport chain with site-specific inhibitors leads to increased formation of CH4 in eukaryote cells, in plants, and in animals. (ii) Conventionally believed as physiologically inert, studies cited in this review demonstrate that exogenous CH4 modulates key events of inflammation. The anti-apoptotic effects of exogenously administered CH4 are also recognized, and these properties also suggest that CH4-mediated intracellular signaling is closely associated with mitochondria. (iii) Mitochondrial substrate oxidation is coupled with the reduction of molecular oxygen, thus providing energy for cellular metabolism. Interestingly, recent in vivo studies have shown improved basal respiration and modulated mitochondrial oxidative phosphorylation by exogenous CH4. Overall, these data suggest that CH4 liberation and effectiveness in eukaryotes are both linked to hypoxic events and redox regulation and support the notion that CH4 has therapeutic roles in mammalian pathophysiologies.
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Affiliation(s)
| | | | - László Juhász
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Eszter Tuboly
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Dániel Érces
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Gabriella Varga
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Petra Hartmann
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
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