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Arturo Tozzi, Minella R. Dynamics and metabolic effects of intestinal gases in healthy humans. Biochimie 2024; 221:81-90. [PMID: 38325747 DOI: 10.1016/j.biochi.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/06/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
Many living beings use exogenous and/or endogenous gases to attain evolutionary benefits. We make a comprehensive assessment of one of the major gaseous reservoirs in the human body, i.e., the bowel, providing extensive data that may serve as reference for future studies. We assess the intestinal gases in healthy humans, including their volume, composition, source and local distribution in proximal as well as distal gut. We analyse each one of the most abundant intestinal gases including nitrogen, oxygen, nitric oxide, carbon dioxide, methane, hydrogen, hydrogen sulfide, sulfur dioxide and cyanide. For every gas, we describe diffusive patterns, active trans-barrier transport dynamics, chemical properties, intra-/extra-intestinal metabolic effects mediated by intracellular, extracellular, paracrine and distant actions. Further, we highlight the local and systemic roles of gasotransmitters, i.e., signalling gaseous molecules that can freely diffuse through the intestinal cellular membranes. Yet, we provide testable hypotheses concerning the still unknown effects of some intestinal gases on the myenteric and submucosal neurons.
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Affiliation(s)
- Arturo Tozzi
- Center for Nonlinear Science, Department of Physics, University of North Texas, 1155 Union Circle, #311427, Denton, TX, 76203-5017, USA.
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Pi XE, Fu H, Yang XX, Yu ZC, Teng WL, Zhang Y, Ye XW, Quan HH, Lu LZ, Liu W. Bacterial, short-chain fatty acid and gas profiles of partially hydrolyzed guar gum in vitro fermentation by human fecal microbiota. Food Chem 2024; 430:137006. [PMID: 37541036 DOI: 10.1016/j.foodchem.2023.137006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 07/17/2023] [Accepted: 07/24/2023] [Indexed: 08/06/2023]
Abstract
Carbohydrates with different structures have metabolic differences in the human body, as well as individual differences. The present study aimed to investigate the effects of bacterial, short-chain fatty acids (SCFAs) and gas profiles of partially hydrolyzed guar gum (PHGG) on the fecal microbiota of 41 Chinese individuals by simulated fermentation in vitro. Results showed that PHGG stimulated the growth of Bifidobacterium and Faecalibacterium, inhibited the growth of Escherichia-Shigella, Klebsiella, and Dorea, and induced the production of fermentation gases (CO2, and H2) and SCFAs (acetic acid, butyric acid). Furthermore, Bifidobacterium was significantly increased in the young female and the old male-originated samples, while Klebsiella was significantly decreased in the old female ones after PHGG intervention, and there were also certain differences in gases and SCFAs among different population samples. These findings indicate that PHGG can modulate gut microbiota and metabolism well, whereas its use varies in different populations.
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Affiliation(s)
- Xiong-E Pi
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310022, China.
| | - Hao Fu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310022, China
| | - Xiao-Xia Yang
- College of Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Zai-Chun Yu
- College of Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Wei-Lin Teng
- Department of Infectious Disease Control and Prevention, HangZhou Center for Disease Control and Prevention, Hangzhou 310006, China
| | - Yinjun Zhang
- College of Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Xue-Wei Ye
- Shulan International Medical College, Department of Basic Medical Sciences, Zhejiang Shuren University, Hangzhou 310015, China.
| | - Hui Hui Quan
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310022, China.
| | - Li-Zhi Lu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310022, China.
| | - Wei Liu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310022, China.
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Zhang X, Ma Q, Jia L, He H, Zhang T, Jia W, Zhu L, Qi W, Wang N. Effects of in vitro fermentation of Atractylodes chinensis (DC.) Koidz. polysaccharide on fecal microbiota and metabolites in patients with type 2 diabetes mellitus. Int J Biol Macromol 2023; 253:126860. [PMID: 37716665 DOI: 10.1016/j.ijbiomac.2023.126860] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/01/2023] [Accepted: 09/09/2023] [Indexed: 09/18/2023]
Abstract
Atractylodes chinensis (DC.) Koidz. polysaccharide (AKP) has been shown to have hypoglycemic activity. In this study, the effects of AKP on fecal microbiota and metabolites in healthy subjects and patients with type 2 diabetes mellitus (T2DM) were investigated using an in vitro simulated digestive fermentation model. AKP were isolated and purified from Atractylodes chinensis (DC.) Koidz. Its main component AKP1 (AKP-0 M, about 78 % of AKP) has an average molecular weight of 3.25 kDa with monosaccharide composition of rhamnose, arabinose, and galactosamine in a molar ratio of 1: 1.25: 2.88. Notably, AKP fermentation might improve the intestinal microbiota of T2DM patients by the enrichment of some specific bacteria rather than the increase of microbial diversity. The addition of AKP specifically enriched Bifidobacteriaceae and weakened the proportion of Escherichia-Shigella. Moreover, AKP also increased the levels of short-chain fatty acids without affecting total gut gas production, suggesting that AKP could have beneficial effects while avoiding flatulence. Metabolomic analysis revealed that ARP fermentation caused changes in some metabolites, which were mainly related to energy metabolism and amino acid metabolism. Importantly, ARP fermentation significantly increased the level of myo-inositol, an insulin sensitizer. In addition, a significant correlation was observed between specific microbiota and differential metabolites. This study has laid a theoretical foundation for AKP application in functional foods.
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Affiliation(s)
- Xin Zhang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, Tianjin 300457, China
| | - Qian Ma
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, Tianjin 300457, China
| | - Lina Jia
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, Tianjin 300457, China
| | - Hongpeng He
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, Tianjin 300457, China
| | - Tongcun Zhang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, Tianjin 300457, China
| | - Weiguo Jia
- The Center of Gerontology and Geriatrics, National Clinical Research Center of Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Liying Zhu
- Institute of Food Science Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Wei Qi
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, Tianjin 300457, China.
| | - Nan Wang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, Tianjin 300457, China.
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Taylor S, Lim P, Cantwell J, D’Souza D, Moinuddin S, Chang YC, Gaze MN, Gains J, Veiga C. Image guidance and interfractional anatomical variation in paediatric abdominal radiotherapy. Br J Radiol 2023; 96:20230058. [PMID: 37102707 PMCID: PMC10230397 DOI: 10.1259/bjr.20230058] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 04/28/2023] Open
Abstract
OBJECTIVES To identify variables predicting interfractional anatomical variations measured with cone-beam CT (CBCT) throughout abdominal paediatric radiotherapy, and to assess the potential of surface-guided radiotherapy (SGRT) to monitor these changes. METHODS Metrics of variation in gastrointestinal (GI) gas volume and separation of the body contour and abdominal wall were calculated from 21 planning CTs and 77 weekly CBCTs for 21 abdominal neuroblastoma patients (median 4 years, range: 2 - 19 years). Age, sex, feeding tubes, and general anaesthesia (GA) were explored as predictive variables for anatomical variation. Furthermore, GI gas variation was correlated with changes in body and abdominal wall separation, as well as simulated SGRT metrics of translational and rotational corrections between CT/CBCT. RESULTS GI gas volumes varied 74 ± 54 ml across all scans, while body and abdominal wall separation varied 2.0 ± 0.7 mm and 4.1 ± 1.5 mm from planning, respectively. Patients < 3.5 years (p = 0.04) and treated under GA (p < 0.01) experienced greater GI gas variation; GA was the strongest predictor in multivariate analysis (p < 0.01). Absence of feeding tubes was linked to greater body contour variation (p = 0.03). GI gas variation correlated with body (R = 0.53) and abdominal wall (R = 0.63) changes. The strongest correlations with SGRT metrics were found for anterior-posterior translation (R = 0.65) and rotation of the left-right axis (R = -0.36). CONCLUSIONS Young age, GA, and absence of feeding tubes were linked to stronger interfractional anatomical variation and are likely indicative of patients benefiting from adaptive/robust planning pathways. Our data suggest a role for SGRT to inform the need for CBCT at each treatment fraction in this patient group. ADVANCES IN KNOWLEDGE This is the first study to suggest the potential role of SGRT for the management of internal interfractional anatomical variation in paediatric abdominal radiotherapy.
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Affiliation(s)
- Sabrina Taylor
- University College London, Centre for Medical Image Computing, London, United Kingdom
| | - Pei Lim
- Department of Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Jessica Cantwell
- Radiotherapy, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Derek D’Souza
- Radiotherapy, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Syed Moinuddin
- Radiotherapy, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Yen-Ching Chang
- Department of Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Mark N Gaze
- Department of Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Jennifer Gains
- Department of Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Catarina Veiga
- University College London, Centre for Medical Image Computing, London, United Kingdom
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Flatus Incontinence and Fecal Incontinence: A Case-Control Study. Dis Colon Rectum 2023; 66:591-597. [PMID: 35333800 DOI: 10.1097/dcr.0000000000002422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Incontinence to gas can be a troublesome symptom impacting quality of life for patients even in the absence of fecal incontinence. Whether isolated flatus incontinence represents part of the spectrum of true fecal incontinence or a separate condition with a different pathophysiology remains unclear. OBJECTIVE This study aimed to evaluate the clinical features and anorectal physiology in women presenting with severe isolated flatus incontinence compared to women with fecal incontinence and healthy asymptomatic women. DESIGN This was a retrospective case-control study of prospectively collected data. SETTINGS Data from participants were obtained from a single tertiary Neurogastroenterology Unit in Sydney, Australia. PATIENTS Data from 34 patients with severe isolated flatus incontinence, 127 women with fecal incontinence' and 44 healthy women were analyzed. MAIN OUTCOME MEASURES The primary outcomes were clinical (including demographic, obstetric, and symptom variables) and physiological differences across the 3 groups. RESULTS Patients with flatus incontinence were significantly younger (mean 39 versus 63 years; p = 0.0001), had a shorter history of experiencing their symptoms ( p = 0.0001), and had harder stool form than patients with fecal incontinence ( p = 0.02). Those with flatus incontinence had an adverse obstetric history and impaired anorectal physiology (motor and sensory, specifically rectal hypersensitivity) but to a lesser extent than patients with fecal incontinence. LIMITATIONS This study was limited by its retrospective design and modest sample size. CONCLUSIONS Anorectal physiology was impaired in patients with flatus incontinence compared to healthy controls, but to a lesser extent than in those with fecal incontinence, raising the possibility that flatus incontinence could be a precursor to fecal incontinence. As clinical and physiological findings are different from healthy controls (including the presence of visceral hypersensitivity), isolated flatus incontinence should be considered a distinct clinical entity (like other functional GI disorders), or possibly part of an incontinence spectrum rather than purely a normal phenomenon. See Video Abstract at http://links.lww.com/DCR/B946 . INCONTINENCIA DE FLATOS E INCONTINENCIA FECAL UN ESTUDIO DE CASOS Y CONTROLES ANTECEDENTES:La incontinencia de gases puede ser un síntoma molesto que afecta la calidad de vida de los pacientes incluso en ausencia de incontinencia fecal. Aún no está claro si la incontinencia de flatos aislada representa parte del espectro de la incontinencia fecal verdadera o una condición separada con una fisiopatología poco clara.OBJETIVO:Evaluar las características clínicas y la fisiología anorrectal en mujeres que presentan incontinencia grave aislada de flatos, en comparación con la incontinencia fecal y mujeres sanas asintomáticas.DISEÑO:Este fue un estudio retrospectivo de casos y controles de datos recolectados prospectivamente.AJUSTE:Los datos de los participantes se obtuvieron de una sola Unidad de Neurogastroenterología terciaria en Sydney, Australia.PACIENTES:Se analizaron los datos de 34 pacientes con incontinencia grave aislada de flatos, junto con 127 mujeres con incontinencia fecal y 44 mujeres sanas.PRINCIPALES MEDIDAS DE RESULTADO:Los resultados primarios fueron clínicos (incluidas las variables demográficas, obstétricas y de síntomas), así como las diferencias fisiológicas entre los tres grupos.RESULTADOS:Los pacientes con incontinencia de flatos eran significativamente más jóvenes (media de 39 años frente a 63 años, p = 0,0001), tenían un historial más corto de experimentar sus síntomas (p = 0,0001) y tenían heces más duras que los pacientes con incontinencia fecal (p = 0,02). Aquellos con incontinencia de flatos tenían antecedentes obstétricos adversos y fisiología anorrectal alterada (motora y sensorial, específicamente hipersensibilidad rectal); aunque en menor medida que las pacientes con incontinencia fecal.LIMITACIONES:Este estudio estuvo limitado por su diseño retrospectivo y tamaño de muestra modesto.CONCLUSIONES:La fisiología anorrectal se vio afectada en las pacientes con incontinencia de flatos en comparación con las controles sanos, pero en menor medida que en aquellas con incontinencia fecal, lo que plantea la posibilidad de que la incontinencia de flatos pueda ser un precursor de la incontinencia fecal. Dado que los hallazgos clínicos y fisiológicos son diferentes a los de los controles sanos (incluida la presencia de hipersensibilidad visceral), la incontinencia de flatos aislada debe considerarse como una entidad clínica distinta (al igual que otros trastornos gastrointestinales funcionales), o posiblemente como parte de un espectro de incontinencia en lugar de un trastorno puramente a un fenómeno normal. Consulte Video Resumen en http://links.lww.com/DCR/B946 . (Traducción-Dr Yolanda Colorado ).
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Oyarzun I, Le Nevé B, Yañez F, Xie Z, Pichaud M, Serrano-Gómez G, Roca J, Veiga P, Azpiroz F, Tap J, Manichanh C. Human gut metatranscriptome changes induced by a fermented milk product are associated with improved tolerance to a flatulogenic diet. Comput Struct Biotechnol J 2022; 20:1632-1641. [PMID: 35465165 PMCID: PMC9014321 DOI: 10.1016/j.csbj.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/02/2022] [Accepted: 04/02/2022] [Indexed: 11/29/2022] Open
Abstract
Healthy plant-based diets rich in fermentable residues may induce gas-related symptoms, possibly mediated by the gut microbiota. We previously showed that consumption of a fermented milk product (FMP) containing Bifidobacterium animalis subsp. lactis CNCM I-2494 and lactic acid bacteria improved gastrointestinal (GI) comfort in response to a flatulogenic dietary challenge in healthy individuals. To study the effects of the FMP on gut microbiota activity from those participants, we conducted a metatranscriptomic analysis of fecal samples (n = 262), which were collected during the ingestion of a habitual diet and two series of a 3-day high-residue challenge diet, before and following 28-days of FMP consumption. Most of the FMP species were detected or found enriched upon consumption of the product. FMP mitigated the effect of a flatulogenic diet on gas-related symptoms in several ways. First, FMP consumption was associated with the depletion of gas-producing bacteria and increased hydrogen to methane conversion. It also led to the upregulation of activities such as replication and downregulation of functions related to motility and chemotaxis. Furthermore, upon FMP intake, metabolic activities such as carbohydrate metabolism, attributed to B. animalis and S. thermophilus, were enriched; these activities were coincidentally found to be negatively associated with several GI symptoms. Finally, a more connected microbial ecosystem or mutualistic relationship among microbes was found in responders to the FMP intervention. Taken together, these findings suggest that consumption of the FMP improved the tolerance of a flatulogenic diet through active interactions with the resident gut microbiota.
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Affiliation(s)
- Iñigo Oyarzun
- Microbiome Lab, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | | | - Francisca Yañez
- Microbiome Lab, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - Zixuan Xie
- Microbiome Lab, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | | | | | - Joaquim Roca
- Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Spain
| | | | - Fernando Azpiroz
- Microbiome Lab, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
| | - Julien Tap
- Danone Nutricia Research, Palaiseau, France
| | - Chaysavanh Manichanh
- Microbiome Lab, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
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Balmus IM, Copolovici D, Copolovici L, Ciobica A, Gorgan DL. Biomolecules from Plant Wastes Potentially Relevant in the Management of Irritable Bowel Syndrome and Co-Occurring Symptomatology. Molecules 2022; 27:molecules27082403. [PMID: 35458601 PMCID: PMC9024464 DOI: 10.3390/molecules27082403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 12/10/2022] Open
Abstract
During and following the processing of a plant’s raw material, considerable amounts are wasted, composted, or redistributed in non-alimentary sectors for further use (for example, some forms of plant waste contribute to biofuel, bioethanol, or biomass production). However, many of these forms of waste still consist of critical bioactive compounds used in the food industry or medicine. Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders. The primary treatment is based on symptomatology alleviation and controlled dietary management. Thus, this review aimed to describe the possible relevance of molecules residing in plant waste that can be used to manage IBS and co-occurring symptoms. Significant evidence was found that many forms of fruit, vegetable, and medicinal plant waste could be the source of some molecules that could be used to treat or prevent stool consistency and frequency impairments and abdominal pain, these being the main IBS symptoms. While many of these molecules could be recovered from plant waste during or following primary processing, the studies suggested that enriched food could offer efficient valorization and prevent further changes in properties or stability. In this way, root, stem, straw, leaf, fruit, and vegetable pomaces were found to consist of biomolecules that could modulate intestinal permeability, pain perception, and overall gastrointestinal digestive processes.
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Affiliation(s)
- Ioana-Miruna Balmus
- Department of Exact Sciences and Natural Sciences, Institute of Interdisciplinary Research, Alexandru Ioan Cuza University of Iasi, Carol I Avenue, no. 11, 700506 Iasi, Romania;
| | - Dana Copolovici
- Faculty of Food Engineering, Tourism and Environmental Protection, Institute for Research, Development and Innovation in Technical and Natural Sciences, “Aurel Vlaicu” University of Arad, Elena Dragoi St., no. 2, 310330 Arad, Romania;
- Correspondence: (D.C.); (A.C.)
| | - Lucian Copolovici
- Faculty of Food Engineering, Tourism and Environmental Protection, Institute for Research, Development and Innovation in Technical and Natural Sciences, “Aurel Vlaicu” University of Arad, Elena Dragoi St., no. 2, 310330 Arad, Romania;
| | - Alin Ciobica
- Department of Biology, Faculty of Biology, Alexandru Ioan Cuza University of Iasi, Carol I Avenue, no. 22a, 700506 Iasi, Romania;
- Correspondence: (D.C.); (A.C.)
| | - Dragos Lucian Gorgan
- Department of Biology, Faculty of Biology, Alexandru Ioan Cuza University of Iasi, Carol I Avenue, no. 22a, 700506 Iasi, Romania;
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Tolonen AC, Beauchemin N, Bayne C, Li L, Tan J, Lee J, Meehan BM, Meisner J, Millet Y, LeBlanc G, Kottler R, Rapp E, Murphy C, Turnbaugh PJ, von Maltzahn G, Liu CM, van Hylckama Vlieg JET. Synthetic glycans control gut microbiome structure and mitigate colitis in mice. Nat Commun 2022; 13:1244. [PMID: 35273143 PMCID: PMC8913648 DOI: 10.1038/s41467-022-28856-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 02/08/2022] [Indexed: 12/14/2022] Open
Abstract
Relative abundances of bacterial species in the gut microbiome have been linked to many diseases. Species of gut bacteria are ecologically differentiated by their abilities to metabolize different glycans, making glycan delivery a powerful way to alter the microbiome to promote health. Here, we study the properties and therapeutic potential of chemically diverse synthetic glycans (SGs). Fermentation of SGs by gut microbiome cultures results in compound-specific shifts in taxonomic and metabolite profiles not observed with reference glycans, including prebiotics. Model enteric pathogens grow poorly on most SGs, potentially increasing their safety for at-risk populations. SGs increase survival, reduce weight loss, and improve clinical scores in mouse models of colitis. Synthetic glycans are thus a promising modality to improve health through selective changes to the gut microbiome.
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Affiliation(s)
| | - Nicholas Beauchemin
- Kaleido Biosciences, Lexington, MA, 02421, USA.,Seres Therapeutics, Cambridge, MA, 02139, USA
| | | | - Lingyao Li
- Kaleido Biosciences, Lexington, MA, 02421, USA
| | - Jie Tan
- Kaleido Biosciences, Lexington, MA, 02421, USA
| | - Jackson Lee
- Kaleido Biosciences, Lexington, MA, 02421, USA
| | - Brian M Meehan
- Kaleido Biosciences, Lexington, MA, 02421, USA.,Pareto Bio, Cambridge, MA, 02140, USA
| | | | - Yves Millet
- Kaleido Biosciences, Lexington, MA, 02421, USA
| | | | | | - Erdmann Rapp
- glyXera GmbH, 39120, Magdeburg, Germany.,Max Planck Institute for Dynamics of Complex Technical Systems, 39106, Magdeburg, Germany
| | - Chris Murphy
- Kaleido Biosciences, Lexington, MA, 02421, USA.,Bacainn Therapeutics, Inc and Morningside BioPharma Advisory, Concord, MA, 01742, USA
| | - Peter J Turnbaugh
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Geoffrey von Maltzahn
- Kaleido Biosciences, Lexington, MA, 02421, USA.,Flagship Pioneering, Cambridge, MA, 02142, USA
| | - Christopher M Liu
- Kaleido Biosciences, Lexington, MA, 02421, USA.,Exo Therapeutics, Watertown, MA, 02472, USA
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9
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Yu X, Gurry T, Nguyen LTT, Richardson HS, Alm EJ. Prebiotics and Community Composition Influence Gas Production of the Human Gut Microbiota. mBio 2020; 11:e00217-20. [PMID: 32900799 PMCID: PMC7482059 DOI: 10.1128/mbio.00217-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/31/2020] [Indexed: 01/01/2023] Open
Abstract
Prebiotics confer benefits to human health, often by promoting the growth of gut bacteria that produce metabolites valuable to the human body, such as short-chain fatty acids (SCFAs). While prebiotic selection has strongly focused on maximizing the production of SCFAs, less attention has been paid to gases, a by-product of SCFA production that also has physiological effects on the human body. Here, we investigate how the content and volume of gas production by human gut microbiota are affected by the chemical composition of the prebiotic and the community composition of the microbiota. We first constructed a linear system model based on mass and electron balance and compared the theoretical product ranges of two prebiotics, inulin and pectin. Modeling shows that pectin is more restricted in product space, with less potential for H2 but more potential for CO2 production. An ex vivo experimental system showed pectin degradation produced significantly less H2 than inulin, but CO2 production fell outside the theoretical product range, suggesting fermentation of fecal debris. Microbial community composition also impacted results: methane production was dependent on the presence of Methanobacteria, while interindividual differences in H2 production during inulin degradation were driven by a Lachnospiraceae taxon. Overall, these results suggest that both the chemistry of the prebiotic and the composition of the microbiota are relevant to gas production. Metabolic processes that are relatively prevalent in the microbiome, such as H2 production, will depend more on substrate, while rare metabolisms such as methanogenesis depend more strongly on microbiome composition.IMPORTANCE Prebiotic fermentation in the gut often leads to the coproduction of short-chain fatty acids (SCFAs) and gases. While excess gas production can be a potential problem for those with functional gut disorders, gas production is rarely considered during prebiotic design. In this study, we combined the use of theoretical models and an ex vivo experimental platform to illustrate that both the chemical composition of the prebiotic and the community composition of the human gut microbiota can affect the volume and content of gas production during prebiotic fermentation. Specifically, more prevalent metabolic processes such as hydrogen production were strongly affected by the oxidation state of the probiotic, while rare metabolisms such as methane production were less affected by the chemical nature of the substrate and entirely dependent on the presence of Methanobacteria in the microbiota.
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Affiliation(s)
- Xiaoqian Yu
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Center for Microbiome Informatics and Therapeutics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Thomas Gurry
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Center for Microbiome Informatics and Therapeutics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Pharmaceutical Biochemistry Group, School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Le Thanh Tu Nguyen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Center for Microbiome Informatics and Therapeutics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Hunter S Richardson
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Eric J Alm
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Center for Microbiome Informatics and Therapeutics, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
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Le Nevé B, Derrien M, Tap J, Brazeilles R, Cools Portier S, Guyonnet D, Ohman L, Störsrud S, Törnblom H, Simrén M. Fasting breath H2 and gut microbiota metabolic potential are associated with the response to a fermented milk product in irritable bowel syndrome. PLoS One 2019; 14:e0214273. [PMID: 30946757 PMCID: PMC6448848 DOI: 10.1371/journal.pone.0214273] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 02/25/2019] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVES Aim of this study was to assess the effect of a fermented milk product containing Bifidobacterium lactis CNCM I-2494 (FMP) on gastrointestinal (GI) symptoms and exhaled H2 and CH4 during a nutrient and lactulose challenge in patients with irritable bowel syndrome (IBS). METHODS We included 125 patients with IBS (Rome III). Fasted subjects were served a 400ml liquid test meal containing 25g lactulose. The intensity of eight GI symptoms and the amount of exhaled H2 and CH4 were assessed before and during 4h after meal intake. The challenge was repeated after 14 days consumption of FMP or a control product in a double-blind, randomized, parallel design. The metabolic potential of fecal microbiota was profiled using 16S MiSeq analysis of samples obtained before and after the intervention. RESULTS 106 patients with IBS were randomized. No difference between FMP or control groups was found on GI symptoms or breath H2 and CH4 in the whole cohort. A post-hoc analysis in patients stratified according to their fasting H2 levels showed that in high H2 producers (fasting H2 level≥10ppm, n = 35), FMP consumption reduced fasting H2 levels (p = 0.003) and H2 production during the challenge (p = 0.002) and tended to decrease GI discomfort (p = 0.05) vs. control product. The Prevotella/Bacteroides metabolic potential at baseline was higher in high H2 producers (p<0.05) vs. low H2 producers and FMP consumption reduced this ratio (p<0.05) vs. control product. CONCLUSIONS The response to a fermented milk product containing Bifidobacterium lactis CNCM I-2494 (FMP) in patients with IBS seems to be associated with the metabolic potential of the gut microbiota. TRIAL REGISTRATION ClinicalTrial.gov NCT01252550. These results were presented as congress posters at Digestive Disease Week 2016 in San Diego, USA and United European Gastroenterology Week 2016 in Vienna, Austria.
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Affiliation(s)
| | | | - Julien Tap
- Danone Nutricia Research, Palaiseau, France
| | | | | | | | - Lena Ohman
- Department of Immunology and Microbiology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Stine Störsrud
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Hans Törnblom
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Magnus Simrén
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Center for Functional Gastrointestinal and Motility Disorders, University of North Carolina, Chapel Hill, North Carolina, United States of America
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Chaudhury A. Raised Cecal Veillonella (Firmicutes)/S 24-7 (Bacteriodetes) May Not Cause Salt-Sensitive Hypertension. Front Physiol 2016; 7:118. [PMID: 27065886 PMCID: PMC4814461 DOI: 10.3389/fphys.2016.00118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 03/15/2016] [Indexed: 11/24/2022] Open
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Proudman CJ, Hunter JO, Darby AC, Escalona EE, Batty C, Turner C. Characterisation of the faecal metabolome and microbiome of Thoroughbred racehorses. Equine Vet J 2014; 47:580-6. [PMID: 25041526 DOI: 10.1111/evj.12324] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 06/20/2014] [Indexed: 01/01/2023]
Abstract
REASONS FOR PERFORMING STUDY The intestinal bacterial community of the horse is a key determinant of intestinal and whole body health. Understanding the bacterial community structure and function is an important foundation for studies of intestinal health and disease. OBJECTIVES To describe the faecal bacterial community and volatile organic compounds (VOCs) of the faecal metabolome of healthy Thoroughbred racehorses and to characterise responses to dietary supplementation with amylase-rich malt extract. STUDY DESIGN Intervention study. METHODS Faecal samples were collected noninvasively before and 6 weeks after supplementation in 8 privately owned Thoroughbred racehorses in active race training. Faecal metabolome was characterised using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS), with spectral analysis performed using AMDIS and compared against the NIST database. Taxonomic description of the faecal microbiota was achieved using error-corrected 454 pyrosequencing data from 16S rRNA gene amplicons. RESULTS The faecal metabolome of our study population was dominated by organic acids, alcohols and ketones. We identified 81 different VOCs only 28 of which were present in >50% of samples indicating functional diversity. Faecal VOC profiles differed between first and second sampling point, some VOCs being significantly reduced post supplementation, consistent with a marked response to dietary amylase-rich malt extract. Faecal microbiota was characterised as highly diverse; samples demonstrated verifiable diversity in the range 1200-3000 operational taxonomic units (OTUs) per individual. The methods used also describe high levels of infrequent, low abundance OTUs. Faecal microbial community structure was found to be different following dietary supplementation. Differences in several low abundance bacterial taxa were detected and also some evidence of interhorse variation in response. CONCLUSIONS The volatile faecal metabolome of Thoroughbred racehorses is dominated by organic acids, alcohols and ketones; this study demonstrates that dietary supplementation with amylase-rich malt extract may significantly alter the profile of VOCs. The faecal microbiome is highly diverse, dominated by Firmicutes and Bacteroidetes. Small but significant changes in microbial community structure were detected following dietary supplementation. This study describes the faecal metabolome and microbiome of healthy Thoroughbred racehorses against which future studies of disease and dietary intervention can be benchmarked.
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Affiliation(s)
- C J Proudman
- School of Veterinary Medicine, University of Surrey, Guildford, UK
| | - J O Hunter
- Gastroenterology Research Unit, Addenbrooke's Hospital, Cambridge, UK
| | - A C Darby
- Institute of Integrative Biology, University of Liverpool, UK
| | - E E Escalona
- Department of Gastroenterology/School of Veterinary Science, University of Liverpool, Neston, UK
| | - C Batty
- Department of Life, Health and Chemical Sciences, Open University, Milton Keynes, UK
| | - C Turner
- Department of Life, Health and Chemical Sciences, Open University, Milton Keynes, UK
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13
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Polag D, Leiß O, Keppler F. Age dependent breath methane in the German population. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 481:582-587. [PMID: 24631621 DOI: 10.1016/j.scitotenv.2014.02.086] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/17/2014] [Accepted: 02/17/2014] [Indexed: 06/03/2023]
Abstract
Methane which can sometimes be found in exhaled breath of humans is known to reflect in situ intestinal methanogenic activity. In recent years, several factors have been studied in order to understand their relevance to methane production in the intestinal tract. However, the relationship between age and methane producing status has hitherto not been sufficiently investigated. In the present study we evaluated the relationship between age and percentage of breath methane producers in the German population in 428 subjects with ages ranging from 4 to 95 years. When subjects were divided into age groups of 15 years, an increase in the percentage of breath methane producers with age was observed. The near linear increase (R(2)=0.977) from 5% for children (1-15 years) to 57% for the elderly (>75 years) may indicate a continuous development in the human gut methanogenic flora throughout lifetime. However, when subjects were compared on 5 year age intervals, an interruption in the percentage of methane producers in the sixth and seventh decade was noted. We further revealed an age dependence on the ratio of female to male producers. This is shown by a dominance in female breath methane producers during the first half of life which afterwards is replaced by a dominance in male breath methane producers with an approximately linear decrease in the ratio between 20 and 65 years (R(2)=0.926). These observations might suggest a relationship between methanogenic activity and hormonal factors. Using our data, we predict that the percentage of breath CH4 producers within the German population will increase from its current value of 30% (2013) to 35% by 2050.
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Affiliation(s)
- Daniela Polag
- Max-Planck-Institut für Chemie, Hahn-Meitner-Weg 1, D-55128 Mainz, Germany
| | - Ottmar Leiß
- Clinic of Gastroenterology, Wallstrasse 1-5, D-55128 Mainz, Germany
| | - Frank Keppler
- Max-Planck-Institut für Chemie, Hahn-Meitner-Weg 1, D-55128 Mainz, Germany
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14
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Oates RW, Schneider ME, Lim Joon M, McPhee NJ, Jones DK, Foroudi F, Collins M, Kron T. A randomised study of a diet intervention to maintain consistent rectal volume for patients receiving radical radiotherapy to the prostate. Acta Oncol 2014; 53:569-71. [PMID: 24237391 DOI: 10.3109/0284186x.2013.854927] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Richard W. Oates
- Radiation Therapy Services, Peter MacCallum Cancer Centre,
Bendigo, Australia
| | - Michal E. Schneider
- Medical Imaging & Radiation Sciences, Monash University, Melbourne, Australia
| | - Michael Lim Joon
- Radiation Oncology, Peter MacCallum Cancer Centre,
Melbourne, Australia
| | | | - Daryl K. Jones
- Radiation Therapy Services, Peter MacCallum Cancer Centre,
Bendigo, Australia
| | - Farshad Foroudi
- Radiation Oncology, Peter MacCallum Cancer Centre,
Melbourne, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne,
Parkville, Australia
| | - Marnie Collins
- Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre,
Melbourne, Australia
| | - Tomas Kron
- Physical Sciences, Peter MacCallum Cancer Centre,
Melbourne, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne,
Parkville, Australia
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Abstract
INTRODUCTION Awareness of the seriousness of irritable bowel disorder (IBS) remains low among clinicians. In this review, we summarize the current knowledge of IBS and highlight the major personal, economic, and social burden of the disease, and the importance of adequate treatment of what is still often viewed as a trivial disorder. In fact, IBS is a major reason for referral. PATHOPHYSIOLOGY It is crucial that the varied pathophysiologies of this complex heterogeneous disease are understood in order to be able to treat both the presenting symptoms (pain, bloating, flatulence, abnormal defecation, diarrhea, constipation) and the underlying disorder effectively. Low-grade inflammatory and immune activation has been observed, but the precise triggers and mechanisms, and the relevance to symptom generation, remain to be established. TREATMENT IBS patients require different treatment strategies according to the pattern, severity, frequency, and symptoms. While initial therapy traditionally targets the most bothersome symptom, long-term therapy aims at maintaining symptom control and preventing recurrence. In addition to dietary/lifestyle interventions and psychosocial strategies, a wide range of pharmacologic therapies are approved for use in IBS depending on the symptoms reported. Musculotropic spasmolytics, which act directly on intestinal smooth muscle contractility, such as otilonium bromide, are effective, particularly in the relief of abdominal pain and bloating, and are well tolerated in IBS. THE OBIS TRIAL: The recent large placebo-controlled Otilonium Bromide in Irritable Bowel Syndrome study demonstrated the superiority of otilonium bromide versus placebo not only in the reduction of pain and bloating, but also in protection from relapse due to the long-lasting effect.
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Affiliation(s)
- Guy Boeckxstaens
- Department of Gastroenterology, Translational Research Center for Gastrointestinal Disorders, University Hospital Leuven, Catholic University of Leuven, Herestraat 49, 3000 Leuven, Belgium
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Whorwell PJ. Unraveling functional abdominal bloating and distension: the role of thoraco-abdominal accommodation and a physical sign to aid its detection. Neurogastroenterol Motil 2012; 24:301-4. [PMID: 22414185 DOI: 10.1111/j.1365-2982.2012.01896.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Bloating and distension are common complaints in patients with irritable bowel syndrome of which the cause has remained elusive, although it has been shown that the obvious explanation of excessive gas is unlikely. The recent application of technologies such as the gas challenge technique, abdominal inductance plethysmography, CT scanning, as well as electromyography of the diaphragm and anterior abdominal wall, have allowed the situation to be slowly unraveled. It is now seems probable that the pathophysiology of bloating and distension are subtly different with the former having a sensory component whereas mechanical factors, such as disordered abdominal accommodation, contribute more to the latter.
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Affiliation(s)
- P J Whorwell
- Department of Translational Medicine, University of Manchester, UK.
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18
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Pregun I, Tulassay Z. [Bowel gases]. Orv Hetil 2008; 149:819-23. [PMID: 18436509 DOI: 10.1556/oh.2008.28352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abdominal bloating is one of the most common symptoms in patients with different gastrointestinal disorders. The majority of patients usually attribute this complaint to increased intestinal gas volume. Recent experimental studies using the gas challenge test help us to better understand the gas dynamics and tolerance in humans. Although there are some clinical conditions that are clearly related to impaired gas dynamics, the role of gases in functional gastrointestinal disorders especially in irritable bowel syndrome is much more complicated. Impaired gas handling, abnormal reflexes and visceral hypersensitivity seem to be the main factors resulting in abdominal bloating in this group of patients. Further clinical studies are needed to clarify the pathophysiologic mechanisms of intestinal gas and this may contribute to the evaluation of optimal therapy.
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Affiliation(s)
- István Pregun
- Semmelweis Egyetem, Altalános Orvostudományi Kar, II. Belgyógyászati Klinika, Budapest.
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Simrén M, Abrahamsson H, Björnsson ES. Lipid-induced colonic hypersensitivity in the irritable bowel syndrome: the role of bowel habit, sex, and psychologic factors. Clin Gastroenterol Hepatol 2007; 5:201-8. [PMID: 17174611 DOI: 10.1016/j.cgh.2006.09.032] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Duodenal lipid infusion increases colonic hypersensitivity in irritable bowel syndrome (IBS). Whether this is affected by bowel habit, psychologic factors, or sex is unknown. METHODS We included 61 patients with IBS (50 women, 11 men), 25 with diarrhea-predominant IBS, 17 with constipation-predominant IBS, 19 with alternating-type IBS, and 20 healthy controls (15 women, 5 men). A colonic distension trial was performed with a barostat before and after a 1-hour duodenal lipid infusion (3 kcal/min). Colonic thresholds, colonic tone, and the viscerosomatic referral pattern were assessed and compared between groups. Patients also completed the Hospital Anxiety and Depression scale. RESULTS The reduction in colonic pressure thresholds after vs before duodenal lipids was greater in patients than in controls for discomfort (P = .006) and pain (P < .0001). An increased viscerosomatic referral area for pain and discomfort during colonic distensions after vs before duodenal lipids was observed in patients but not in controls. The response was similar in IBS subgroups based on the predominant bowel habit, in patients with vs without anxiety and/or depression, and in women and men with IBS. The colonic tone response during lipid infusion was similar in IBS patients and controls, and in the different IBS subgroups. CONCLUSIONS IBS patients show increased colonic sensitivity and altered viscerosomatic referral pattern after duodenal lipids. This response is largely unaffected by the predominant bowel habit, psychologic factors, or sex, but seems to be related to IBS per se.
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Affiliation(s)
- Magnus Simrén
- Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg, Sweden.
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Simrén M, Agerforz P, Björnsson ES, Abrahamsson H. Nutrient-dependent enhancement of rectal sensitivity in irritable bowel syndrome (IBS). Neurogastroenterol Motil 2007; 19:20-9. [PMID: 17187585 DOI: 10.1111/j.1365-2982.2006.00849.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Food-related gastrointestinal symptoms are common in irritable bowel syndrome (IBS), but the mechanisms behind this are unclear. Enhanced colorectal sensitivity after duodenal lipid administration in IBS patients has been demonstrated. However, the effects of a regular meal on colorectal sensitivity in these patients and the importance of the composition of the meal are not known. On two separate days, 10 IBS patients and 11 controls randomly received a liquid meal (800 kcal), containing 60% calories from fat (fatty meal) or carbohydrate (carbohydrate meal). Using a barostat rectal sensitivity was assessed during four separate distension sequences before, immediately after and 30 and 60 min after the meal. In the patients, the discomfort (P = 0.04) and the pain thresholds (P = 0.007) were gradually reduced after the fatty meal, whereas only a tendency in the same direction was seen after the carbohydrate meal. In patients VAS ratings for pain increased after the fatty meal (P = 0.03), but not after carbohydrates. In the controls, sensory thresholds were not affected by the meals. In IBS, a liquid meal enhances rectal sensitivity, and this seems to be partly nutrient dependent as a fatty meal has more pronounced effects than a carbohydrate meal. This might be of relevance for their postprandial symptoms.
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Affiliation(s)
- M Simrén
- Department of Internal Medicine, Section of Gastroenterology and Hepatology, Sahlgrenska University Hospital, Göteborg, Sweden.
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Abstract
PURPOSE OF REVIEW To review recently published studies investigating any association between gut flora and symptoms of irritable bowel syndrome. RECENT FINDINGS Experimental studies demonstrate associations between gut flora, gut motility, mucosal inflammation and visceral hypersensitivity. Scientific bases for possible benefits of selected probiotics on irritable bowel symptoms have been identified. Disturbances in viable counts of fecal flora have been demonstrated in patients with irritable bowel syndrome. Results of studies based on breath tests are conflicting as to whether the prevalence of small intestinal bacterial overgrowth is increased in this group. Nonetheless, a longitudinal analysis based on bacteriological assessments of serial small intestinal aspirates suggests that this entity should be considered in patients with irritable bowel symptoms, especially in the setting of predisposition to bacterial overgrowth. Clinical trials of probiotic treatment for irritable bowel syndrome have yielded conflicting results. SUMMARY Recent studies provide increasing support for the concept that disturbances in gut flora occur in patients with irritable bowel syndrome and that such abnormalities may contribute to irritable bowel syndrome-type symptoms. The relative importance of disturbed gut flora to symptom pathogenesis, along with the therapeutic potential of modulation of the gut flora for amelioration of irritable bowel syndrome symptoms, however, remains to be fully defined.
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Affiliation(s)
- Stephen M Riordan
- Gastrointestinal and Liver Unit and University of New South Wales, Sydney, NSW, Australia.
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