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Yersin S, Vonaesch P. Small intestinal microbiota: from taxonomic composition to metabolism. Trends Microbiol 2024:S0966-842X(24)00056-8. [PMID: 38503579 DOI: 10.1016/j.tim.2024.02.013] [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: 11/30/2023] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/21/2024]
Abstract
The small intestinal microbiota (SIM) is essential for gastrointestinal health, influencing digestion, immune modulation, and nutrient metabolism. Unlike the colonic microbiota, the SIM has been poorly characterized due to sampling challenges and ethical considerations. Current evidence suggests that the SIM consists of five core genera and additional segment-specific taxa. These bacteria closely interact with the human host, regulating nutrient absorption and metabolism. Recent work suggests the presence of two forms of small intestinal bacterial overgrowth, one dominated by oral bacteria (SIOBO) and a second dominated by coliform bacteria. Less invasive sampling techniques, omics approaches, and mechanistic studies will allow a more comprehensive understanding of the SIM, paving the way for interventions engineering the SIM towards better health.
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Affiliation(s)
- Simon Yersin
- Department of Fundamental Microbiology, Université de Lausanne, Lausanne, Switzerland
| | - Pascale Vonaesch
- Department of Fundamental Microbiology, Université de Lausanne, Lausanne, Switzerland.
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Pesu H, Mbabazi J, Mutumba R, Savolainen O, Olsen MF, Mølgaard C, Michaelsen KF, Ritz C, Filteau S, Briend A, Mupere E, Friis H, Grenov B. Correlates of Plasma Citrulline, a Potential Marker of Enterocyte Mass, among Children with Stunting: A Cross-Sectional Study in Uganda. J Nutr 2024; 154:765-776. [PMID: 38135004 DOI: 10.1016/j.tjnut.2023.12.027] [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: 10/03/2023] [Revised: 12/11/2023] [Accepted: 12/18/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND Environmental enteric dysfunction (EED) is associated with stunting. Citrulline, produced in mature enterocytes, may be a valuable biomarker of small intestinal enterocyte mass in the context of EED. OBJECTIVES We aimed to explore the correlates of plasma citrulline (p-cit) in children with stunting. METHODS In a cross-sectional study using baseline data from the community-based MAGNUS (milk affecting growth, cognition and the gut in child stunting) trial (ISRCTN13093195), we explored potential correlates of p-cit in Ugandan children with stunting aged 12-59 mo. Using linear regression in univariate and multivariate models, we explored associations with socioeconomics, diet, micronutrient status, and water, sanitation, and hygiene characteristics. The influence of covariates age, fasting, and systemic inflammation were also explored. RESULTS In 750 children, the mean ± standard deviation age was 32.0 ± 11.7 mo, and height-for-age z-score was -3.02 ± 0.74. P-cit, available for 730 children, differed according to time fasted and was 20.7 ± 8.9, 22.3 ± 10.6 and 24.2 ± 13.1 μmol/L if fasted <2, 2-5 and >5 h, respectively. Positive correlates of p-cit were age [0.07; 95% confidence interval (CI): 0.001, 0.15 μmol/L] and log10 serum insulin-like growth factor-1 (8.88; 95% CI: 5.09, 12.67 μmol/L). With adjustment for systemic inflammation, the association with serum insulin-like growth factor-1 reduced (4.98; 95% CI: 0.94, 9.03 μmol/L). Negative correlates of p-cit included food insecurity, wet season (-3.12; 95% CI: -4.97, -1.26 μmol/L), serum C-reactive protein (-0.15; 95% CI: -0.20, -0.10 μmol/L), serum α1-acid glycoprotein (-5.34; 95% CI: -6.98, -3.70 μmol/L) and anemia (-1.95; 95% CI: -3.72, -0.18 μmol/L). Among the negatively correlated water, sanitation, and hygiene characteristics was lack of soap for handwashing (-2.53; 95% CI: -4.82, -0.25 μmol/L). Many associations attenuated with adjustment for inflammation. CONCLUSIONS Many of the correlates of p-cit are characteristic of populations with a high EED prevalence. Systemic inflammation is strongly associated with p-cit and is implicated in EED and stunting. Adjustment for systemic inflammation attenuates many associations, reflecting either confounding, mediation, or both. This study highlights the complex interplay between p-cit and systemic inflammation.
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Affiliation(s)
- Hannah Pesu
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Joseph Mbabazi
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark; Department of Paediatrics and Child Health, School of Medicine College of Health Sciences, Makerere University, Kampala, Uganda
| | - Rolland Mutumba
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark; Department of Paediatrics and Child Health, School of Medicine College of Health Sciences, Makerere University, Kampala, Uganda
| | - Otto Savolainen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; Faculty of Health Sciences, Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland
| | - Mette F Olsen
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Christian Mølgaard
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Kim F Michaelsen
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Christian Ritz
- National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark
| | - Suzanne Filteau
- Department of Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - André Briend
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark; Tampere Centre for Child Health Research, Tampere University, Tampere, Finland
| | - Ezekiel Mupere
- Department of Paediatrics and Child Health, School of Medicine College of Health Sciences, Makerere University, Kampala, Uganda
| | - Henrik Friis
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Benedikte Grenov
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark.
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