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Updated: May 15, 2025
An In Vitro Batch-culture Model to Estimate the Effects of Interventional Regimens on Human Fecal Microbiota
Published on: July 31, 2019
Host-microbiota interactions in the infant gut revealed by daily faecal sample time series
Nienke van Beek1, Iiris Katavisto1, Markku Lehto2,3,4
1Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsink 00014, Finland.
Insights
Host immune factors and gut microbes interact differently in infants as they age. Biomarker analysis of daily stool samples reveals changing host regulation of the gut microbiota over time.
Area of Science:
- Microbiome research
- Immunology
- Pediatric health
Background:
- The infant gut microbiome and immune system undergo rapid development.
- Understanding host-microbe interactions is crucial for infant health.
- Biomarkers can provide insights into these dynamic processes.
Purpose of the Study:
- To investigate the interplay between host immune factors and gut microbiota in infants.
- To identify biomarkers reflecting host-microbe interactions in infant stool.
- To analyze age-associated changes in these interactions.
Main Methods:
- Analysis of 216 daily stool samples from infants aged 5-6 and 11-12 months.
- Assessment of gut microbiota composition and total bacterial load.
- Measurement of immune biomarkers including ECP, IgA, calprotectin, IAP, BPI, LCN2, LTF, and alpha-defensin-5.
Main Results:
- Microbial stimulation of several immune biomarkers (ECP, IgA, Cal, IAP, BPI) observed at 6 and 12 months.
- LCN2, LTF, and alpha-defensin-5 were stimulated only at 6 months.
- Positive associations between biomarkers and bacteria at 6 months shifted to negative at 12 months, indicating increased host regulation with age.
Conclusions:
- Host-microbe interactions and immune responses evolve with age in infants.
- Albumin and LCN2 may serve as markers for gut permeability and transit time, respectively.
- Mucin2 and IAP are potentially key regulators of the infant gut bacterial populations.
Abstract:
Aim: This study aims to explore the interplay between host immune factors and gut microbiota in human infants in vivo using time-series daily stool samples and identify biomarkers of host-microbe interactions. Methods: 216 faecal samples collected from infants aged 5-6 or 11-12 months were analysed for gut microbiota composition, total bacterial load, and biomarkers of immune function. Results: We identified indications of microbial stimulation of eosinophil cationic protein (ECP), IgA, calprotectin (Cal), intestinal alkaline phosphatase (IAP), and Bactericidal/permeability-increasing protein (BPI) at 6 and 12 months, as well as stimulation of lipocalin 2 (LCN2), lactoferrin (LTF), and alpha-defensin-5 only at 6 months. The associations between biomarker concentrations and bacterial population growth were primarily positive at 6 months and mostly negative at 12 months, suggesting increasing host regulation of the microbiota with age. The exceptions were IAP, which was predictive of declining bacterial populations at both time points, and Cal, whose associations changed from negative at 6 months to positive at 12 months. Conclusion: There is an age-associated development in the correlation pattern between bacterial population growth and the biomarker concentrations, suggesting that host-microbe interactions change during early development. Albumin appeared as a potential marker of gut permeability, while LCN2 seemed to correlate with gut transit time. Mucin degradation appeared to decrease with age. Mucin2 and IAP emerged as potentially important regulators of the bacterial populations in the infant gut. The study demonstrates the utility of biomarker and bacteria profiling from daily stool samples for analysing in vivo associations between the immune system and the gut microbiota and provides evidence of host regulation of the microbiota in infants.
