Gastrointestinal tissue as a “new” target of pollution exposure

Abstract

Airborne pollution has become a leading cause of global death in industrialized cities and the exposure to environmental pollutants has been demonstrated to have adverse effects on human health. Among the pollutants, particulate matter (PM) is one of the most toxic and although its exposure has been more commonly correlated with respiratory diseases, gastrointestinal (GI) complications have also been reported as a consequence to PM exposure. Due to its composition, PM is able to exert on intestinal mucosa both direct damaging effects, (by reaching it either via direct ingestion of contaminated food and water or indirect inhalation and consequent macrophagic mucociliary clearance) and indirect ones via generation of systemic inflammation. The relationship between respiratory and GI conditions is well described by the lung‐gut axis and more recently, has become even clearer during coronavirus disease 2019 (COVID‐19) pandemic, when respiratory symptoms were associated with gastrointestinal conditions. This review aims at pointing out the mechanisms and the models used to evaluate PM induced GI tract damage.

Vitamin C compounds mixture prevents skin barrier alterations and inflammatory responses upon real life multi pollutant exposure

“…17 It is likely that PM and pollution in general are able to disrupt the skin barrier function, by modulating or even degrading the TJs, such as Desmocolin-1 and Claudin-1, as shown in our experiments. Similar mechanism has been suggested for other organs directly exposed to the outdoor stressors such as lung 25 and intestine, 51,52 confirming the detrimental effect of pollution on human health.…”

Particulate matter exposure may increase the risk of irritable bowel syndrome: a large-scale prospective study based on the UK Biobank

“…It is reported that the gastrointestinal tract could be a target organ of PM exposure and the daily intake of PM (10 12 –10 14 particles per day) by food and water should not be ignored. 13 Besides, the PM deposited in the nose or respiratory tract could be removed by the gastrointestinal tract via mucociliary clearance by deglutition behavior. 8 Additionally, PM in the respiratory tract may also cross the lung epithelial barrier and consequently reach the gastrointestinal tract by blood circulation.…”

“…Moreover, it could also get into the digestive tract through contaminated food and water, mucociliary clearance of the respiratory tract, and blood circulation. [13][14][15] Based on the Integrated Science Assessment (ISA) of PM, nearly 71% of the PM deposited in the nose will consequently enter the gastrointestinal tract. 8 This indicates that, for PM, the gastrointestinal exposure pathway is important and should not be ignored.…”

The Physiological Effects of Air Pollution: Particulate Matter, Physiology and Disease

“…Mucociliary clearance of PM from the lungs followed by its ingestion within saliva leads to gastrointestinal PM exposure. A growing body of preclinical data has revealed PM-induced gastrointestinal inflammation and gut microbiome changes (123)(124)(125). In mice, PM exposure altered the relative proportions of microbiota component species, impaired gut permeability through oxidative stress and increased proinflammatory cytokine expression in an interleukin-10 knock out model of inflammatory bowel disease (123)(124)(125).…”

“…A growing body of preclinical data has revealed PM-induced gastrointestinal inflammation and gut microbiome changes (123)(124)(125). In mice, PM exposure altered the relative proportions of microbiota component species, impaired gut permeability through oxidative stress and increased proinflammatory cytokine expression in an interleukin-10 knock out model of inflammatory bowel disease (123)(124)(125). However, epidemiological studies have not yet identified a clear link between PM exposure and inflammatory bowel disease (126).…”