PM2.5 exposure associated with microbiota gut-brain axis: Multi-omics mechanistic implications from the BAPE study

Impact of Air Pollution on the Composition and Diversity of Human Gut Microbiota in General and Vulnerable Populations: A Systematic Review

“…Finally, 12 articles were considered eligible to be included in the systematic review, but 2 articles were excluded for missing data. A total of 10 articles were used for the data extraction [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. The PRISMA flow diagram in Figure 1 illustrates the search results.…”

“…The included studies (nine cross-sectional and one cohort study) were published from 2018 to 2022 [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ] ( Table 2 ). Among the ten studies, two of them were conducted in America [ 39 , 45 ], seven in China [ 36 , 37 , 38 , 40 , 41 , 42 , 43 ], and one in Europe (Finland) [ 44 ], and the sample size was very variable, ranging from 21 to 6627 subjects.…”

“…Regarding exposure time, short-term exposure (from 2 to 5 days) to air pollutants was considered in four studies [ 37 , 41 , 42 ], whereas long-term exposure (28 days to 2 years) was investigated in six studies [ 36 , 38 , 39 , 40 , 44 , 45 ]. Moreover, the methods of exposure assessments varied among studies: daily air quality index scores assigned using the monitoring data of China National Environmental Monitoring Centre [ 38 ], levels of urbanization [ 40 ], ambient monitoring station [ 41 ], real-time personal exposure [ 37 , 42 ], passive sampling devices [ 44 ], and other various modelled estimates ( n = 3) [ 36 , 43 , 45 ] were used ( Table 1 ).…”

“…The region of amplification of the 16S rDNA gene varied among studies, such as V4 ( n = 4), V3–V4 ( n = 2), and V5 ( n = 1) ( Table 2 ). Two studies mentioned that they used three different regions (V4, V3–4, and V4–5), but it was unclear how these analyses were integrated into bacteria characterization [ 37 , 42 ]. Moreover, the primers used for the amplification varied across studies: three studies used 515F/806R primers, and two used 341F/805R and 338F/806R, respectively ( Table 2 ).…”

Impact of Environmental Pollutants on Gut Microbiome and Mental Health via the Gut–Brain Axis

“…PM and ozone, two common contaminants with different characteristics and reactivity, have been shown in experiments to activate the HPA axis and release glucocorticoid stress hormones as part of a neuroendocrine stress response [ 186 , 187 ] that may modulate the composition of intestinal flora through receptors that are comparable to adrenergic receptors in their action [ 188 , 189 ]. According to an epidemiological study conducted using a combination of multi-omics and multi-indicator technology, PM 2.5 may activate GBA by altering the gut microbiota, tryptophan metabolism, inflammatory factors and key HPA axis hormones, resulting in neurological and psychological dysfunction [ 190 ].…”