Exposures to Semivolatile Organic Compounds in Indoor Environments and Associations with the Gut Microbiomes of Children

Abstract

Semivolatile organic compounds (SVOCs) are widely detected in many indoor environments due to their frequent use in building materials, textiles, furniture, electronics, and other consumer products. Biomarkers of SVOC exposures have been consistently measured in biological samples across the globe, presenting uncertainty about their potential impacts on sensitive populations. To begin unravelling the dynamics between gut microbiome maturation and chronic exposure to complex chemical mixtures, this study characterized the prokaryotic and fungal gut microbiomes of children (ages 3− 6) in a North Carolina cohort and examined their relationships with SVOC exposures. SVOC biomarkers were detected ubiquitously in pooled urine samples, with 29 compounds detected in >95% of samples. In total, 61 bacterial taxon−biomarker and 24 fungal taxon−biomarker pairs displayed statistically significant relationships (i.e., minimum positive r s ≥ 0.2 or minimum negative r s ≤ −0.2; p < 0.05), with disparate trends noted for bacteria and fungi. Sm-PFOS was associated with declines in several bacterial taxa (r s ≤ −0.21; p ≤ 0.05), while phthalate metabolites like MHiBP were negatively associated with fungi (r s ≤ −0.45). Finally, 10 genera historically capable of reductive dehalogenation displayed significant positive associations with halogenated SVOCs (e.g., biomarkes of chlorobenzenes such as 2,4-DCP), suggesting these compounds may act as a selective pressure within developing gut microbiomes.

Effects of Lifetime Exposures to Environmental Contaminants on the Adult Gut Microbiome

“…For instance, elevated PFAS exposures were associated with decreases in several distinct bacterial clades. 68 Higher PFAS concentrations in breastmilk were also associated with a 5% decline in infant alpha diversity and increases in Enterococcus in a cross-sectional Norwegian study. 69 However, none of these previous studies on the impact of PFAS investigated toxicant exposure at multiple time points, with a prospective life trajectory design, and none utilized a comprehensive set of statistical approaches to investigate multiple components of the microbiome.…”

“…Few recent epidemiological studies investigated the potential effects of exposure to environmental pollutants on the gut microbiome. For instance, elevated PFAS exposures were associated with decreases in several distinct bacterial clades . Higher PFAS concentrations in breastmilk were also associated with a 5% decline in infant alpha diversity and increases in Enterococcus in a cross-sectional Norwegian study .…”

Chronic Systemic Low-Grade Inflammation and Modern Lifestyle: The Dark Role of Gut Microbiota on Related Diseases with a Focus on COVID-19 Pandemic

“…Notably, blood, urine, and fecal samples were tested for 44 SVOCs, and 29 substances were present in >95% of the analysis. In addition, the PFOS presence was associated with a decline in several bacterial and fungi taxa, and halogenated SVOCs increased the abundance of dehalogenating bacteria, demonstrating a pressure of SVOCs on the microbiome [196].…”

Evaluation of developing maize microbiomes and associations among nitrogen cyclers and key fungal taxa

“…Similar bioinformatics pipelines were applied to both 16S rRNA gene reads and fungal ITS region reads [52]. Reads were trimmed, filtered for quality and analysed using the DADA2 package in R according to the standard package protocol for the 16S rRNA gene and fungal ITS gene [54,55].…”

“…bacteria and archaea) and fungal communities (n=3 per sampling location), respectively. Prokaryotic communities were targeted using 16S rRNA primer sequences 314F and 805R (5′-CCTACGGGNBGCASCAG-3′ and 5′-GACTACNVGGGTATCTAACC-3′, respectively) [51,52]. These primers span the V3-V4 16S rRNA regions and have increased degeneracy to target both bacteria and archaea.…”