Metallomics Reviews
Prenatal Metals, Gut Microbiome and Child Inflammation
Clinical Overview
This birth-cohort study from Mexico City links prenatal exposure to multiple metals, childhood gut microbiome composition, and late-childhood intestinal inflammation, measured by fecal calprotectin (FC) at 9–11 years. Low third-trimester whole-blood copper and cesium, combined with specific microbial profiles (notably low Eubacterium ventriosum or high Roseburia inulinivorans and Ruminococcus torques), defined “metal–microbial clique signatures” associated with markedly elevated odds of FC ≥100 μg/g (OR 7.21–10.27). These data suggest that specific prenatal metal milieus may program microbiome–host interactions that manifest as subclinical intestinal inflammation in otherwise healthy children.
What was reviewed and who was studied
The paper evaluates 108 children (57% male) from the PROGRESS longitudinal birth cohort in Mexico City, whose mothers had whole-blood levels of 11 metals measured by ICP-QQQ during the second and third trimesters. Children provided stool at 8–11 years for shotgun metagenomic profiling and FC measurement. Elevated FC was defined as ≥100 μg/g stool. Using interpretable machine-learning (repeated hold-out signed-iterated Random Forest, rh-SiRF) plus regression, the authors identified multi-metal, multi-microbe “clique signatures” associated with high FC in late childhood.
Major findings
| Finding | Detail |
|---|---|
| Cohort characteristics and FC burden | Median FC was 43.9 μg/g (IQR 91.8), with children sampled at mean age 9.67 years; α and β diversity metrics were not associated with elevated FC. |
| Individual metals vs FC | In covariate-adjusted logistic models with trimester-specific quartiles of maternal whole-blood metals (As, Cu, Cr, Cd, Se, Sb, Pb, Cs, Zn, Mn, Co), no single metal showed a statistically significant association with FC ≥100 μg/g. Forest plots on page 4 support largely null effect estimates. |
| Individual taxa vs FC | Higher Eubacterium ventriosum and Faecalibacterium prausnitzii relative abundances were associated with lower odds of elevated FC (E. ventriosum OR 0.33, 95% CI 0.18–0.63; F. prausnitzii OR 0.56, 95% CI 0.32–0.99), while Ruminococcus torques was positively associated with elevated FC (volcano plot, Figure 1B, page 4). Only E. ventriosum remained significant after FDR correction. |
| Metal–microbial clique 1: Cs–Cu–E. ventriosum | A clique defined by low third-trimester cesium and copper (below the 70th–80th percentiles) plus low E. ventriosum (below the sample median) identified 29.6% of children and was strongly associated with FC ≥100 μg/g (OR 10.27, 95% CI 3.57–29.52; FDR <0.001). Density and bar plots on page 5 show a shift to higher FC in this subgroup. |
| Metal–microbial clique 2: Cu–R. inulinivorans–R. torques | A second clique with low third-trimester copper (below median) plus high R. inulinivorans and R. torques (above 60th percentiles) encompassed 11.1% of children and was associated with elevated FC (OR 7.21, 95% CI 1.81–28.77; FDR <0.05). |
| Robustness checks | Associations for metal–microbial cliques persisted with adjustment for Shannon diversity, altered thresholds (±10 percentiles), permutation-derived p-values, continuous FC, and log-binomial models. Analysis in the 30% test subset preserved directionality, despite wide CIs. |
Implications for Microbial Metallomics
The study links the prenatal metallome—especially third-trimester copper and cesium status—to later microbiome configurations that stratify risk of subclinical gut inflammation in children.
| Concept | Implication |
|---|---|
| Low prenatal copper and cesium with low E. ventriosum | A specific low-Cu/low-Cs milieu may program offspring toward a microbial pattern characterized by reduced E. ventriosum, jointly conferring a >10-fold higher odds of elevated FC, suggesting a metallomics–microbiome axis that predisposes to intestinal inflammation. |
| Low prenatal copper with high R. inulinivorans and R. torques | Copper deficiency-range exposure may favor microbial assemblages enriched in R. inulinivorans and R. torques that associate with elevated FC, pointing to taxon-specific copper sensitivity or copper-mediated niche competition. |
| Null single-metal effects but strong clique effects | The absence of robust single-metal associations yet strong metal–microbial clique signals underscores that prenatal metal effects on intestinal inflammation are highly interaction-dependent, advocating for metallomic analyses that explicitly model synergistic structures. |
| Taxa associated with lower FC (E. ventriosum, F. prausnitzii) | These taxa may represent inflammation-protective components whose depletion, especially within particular prenatal metal contexts, is a candidate intermediate for metal-driven intestinal inflammation pathways. |
| Subclinical FC as a microbiome–metallome readout | FC ≥100 μg/g, chosen for clinical relevance, functions here as a biomarker that integrates prior metal exposure and current microbial structure, making it a practical endpoint for future metallomic–microbiome screening in pediatrics. |
| Interpretable machine learning for metallomic cliques | The rh-SiRF–based clique discovery strategy provides a scalable, replicable template for identifying high-order metal–microbe interactions in other cohorts and disease contexts, moving microbial metallomics toward precision risk stratification. |
Limitations
The sample is modest (n=108), which constrains power and inflates uncertainty for higher-order interactions, as reflected in wide confidence intervals. Gut microbiome and FC were measured at a single time point, limiting temporal inference. Maternal and child diet, maternal IBD status, and maternal FC were unavailable, and clinical IBD outcomes were not captured, so links to overt disease remain speculative within this dataset.
Future perspectives
Next steps include replicating these copper/cesium–microbiome cliques in larger, ethnically diverse cohorts with serial stool sampling across childhood, integrating dietary data and maternal IBD status. Mechanistic work should interrogate how low-range prenatal copper and cesium exposures alter microbial colonization trajectories and inflammatory tone, for example by longitudinally pairing metallomic profiles with metagenomic and FC trajectories. Ultimately, embedding these clique-based metallomic signatures into exposome-informed prediction tools could support early identification of children at high risk of persistent intestinal inflammation and, in future, personalized preventive strategies.
Key takeaways for Researchers and Clinicians
In Mexican children aged 9–11 years, prenatal maternal whole-blood metals (11-element panel) and child stool metagenomes were jointly analyzed against FC-defined intestinal inflammation. Copper and cesium in late pregnancy, not as isolated predictors but as components of metal–microbial clique signatures, were central: low third-trimester copper (with or without low cesium) combined with specific taxa—low E. ventriosum or high R. inulinivorans and R. torques—identified subgroups with 7–10-fold higher odds of FC ≥100 μg/g.
Methodologically, the study showcases shotgun metagenomics paired with rh-SiRF clique discovery and covariate-adjusted regression as a practical pipeline for uncovering high-order metal–microbe interactions from standard whole-blood and stool matrices. Clinically, while no immediate therapeutic decisions follow, FC and microbial taxa such as E. ventriosum, F. prausnitzii, and R. torques emerge as candidate biomarkers for latent, exposure-linked intestinal inflammation. The translational hook is clear: prenatal metallomic fingerprints, interpreted through microbiome structure, may help define high-risk pediatric subgroups long before overt IBD manifests.
Citation
Midya V, Agrawal M, Lane JM, et al. Association between Exposure to Metals during Pregnancy, Childhood Gut Microbiome, and Risk of Intestinal Inflammation in Late Childhood. Environ Health. 2024;2:739–749