Gut microbiota-mediated poly(ε-caprolactone) microplastic degradation exacerbates metabolic dysregulation

Area of Science:

• Environmental Science
• Toxicology
• Microbiology

Background:

• Biodegradable plastics (BPs) like poly(ε-caprolactone) (PCL) are widely used but degrade into microplastics (MPs).
• Human exposure and accumulation of PCL MPs are increasing, yet their health effects are poorly understood.

Purpose of the Study:

• To investigate the impact of PCL MPs on lipid metabolism, intestinal barrier function, and gut microbiota composition.
• To explore the role of gut microbiota in mediating the adverse effects of PCL MPs.

Main Methods:

• Exposure of mice to PCL MPs.
• Analysis of lipid metabolism markers, intestinal barrier integrity (tight junction proteins, mucin), and gut microbiota composition (16S rRNA sequencing).
• Isolation and characterization of PCL-degrading bacteria from gut microbiota.

Main Results:

• PCL MPs promoted lipid synthesis, inhibited lipid oxidation and secretion, and exacerbated high-fat diet-induced metabolic syndrome in mice.
• Intestinal barrier disruption was observed, indicated by an increased Firmicutes/Bacteroidetes ratio, altered microbial abundance, and reduced tight junction protein and mucin expression.
• The PCL-degrading bacterium Brevibacillus formosus P9 was identified and implicated in mediating PCL MP-induced metabolic disruption.

Conclusions:

• PCL MPs pose physiological risks by disrupting lipid metabolism and intestinal homeostasis.
• Gut microbiota, particularly PCL-degrading strains, can amplify the detrimental effects of PCL MPs.
• Urgent attention is needed regarding the widespread use of biodegradable plastics due to potential health concerns.