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Incorporation of polylactic acid microplastics into the carbon cycle as a carbon source to remodel the endogenous metabolism of the gut
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Researchers discovered that gut bacteria can break down so-called biodegradable PLA microplastics and incorporate the carbon into their own metabolism, fundamentally altering the gut's energy balance. This process reduced beneficial short-chain fatty acids that fuel gut lining cells and caused decreased appetite and weight loss in mice, suggesting that biodegradable plastics may not be as harmless inside the body as assumed.
Biodegradable polylactic acid (PLA) plastics have been praised as an effective solution to the global pollution caused by petroleum-based plastics, and their widespread use in food packaging and disposable tableware has resulted in increased oral exposure to PLA microplastics (PLA-MPs). Despite their eco-friendly and biodegradable reputation, the in vivo behaviors of PLA-MPs concerning fermentation, carbon cycle, and adverse effects remain unknown. Here, we showed that gut microbiota from the colon can effectively degrade the PLA-MPs by secreting esterase FrsA, whereas esterase FrsA-producing bacteria were identified to dominate this behavior in male C57BL/6 mice. Using isotope tracing and multiomics techniques, we uncovered that 13C-labeled PLA-MPs were incorporated into the carbon cycle of gut microbiota as a carbon source. Meanwhile, these degraded PLA-MPs fragments entered the succinate pathway of the tricarboxylic acid cycle within gut epithelial cells. These processes altered the metabolic phenotype of the gut, resulting in the decreased linear short-chain fatty acids that are primary energy sources of the gut epithelium. Furthermore, we found that exposure of PLA-MPs significantly reduced the appetite and body weight of mice. Our findings present an overall process of biodegradable plastics within hosts, with the focus on the entire double carbon cycle of PLA-MPs in the gut, which offers indispensable insights into the potential impact of exposure to PLA-MPs.
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Polylactic acid microplastics as metabolic disruptors: Linking gut dysbiosis to systemic toxicity by disrupting microbiota-host co-metabolism.
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This review pulls together existing research on tiny plastic particles from polylactic acid (PLA)—a "biodegradable" plastic used in things like food packaging and disposable cutlery—showing they can build up in the gut, damage its protective lining, and throw off the balance of gut bacteria. Scientists think this gut disruption may trigger inflammation and even affect the liver and body-wide metabolism, though this specific chain of events hasn't been directly proven yet for PLA particles. The takeaway: even "eco-friendly" plastics may carry hidden health risks, and more research is needed to understand exactly how they affect our
Simulated gastrointestinal digestion of polylactic acid (PLA) biodegradable microplastics and their interaction with the gut microbiota
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Researchers simulated what happens when humans swallow polylactic acid (PLA) microplastics, a common bioplastic labeled as biodegradable, by running them through an artificial digestive system. While PLA did not dramatically alter the overall gut bacterial community, it did increase certain bacteria and change how the microbial community metabolized nutrients. The study also found that stomach acid caused physical changes to the PLA particles, suggesting that even supposedly safe bioplastics may interact with our gut in ways we do not yet fully understand.
Simulated gastrointestinal digestion of two different sources of biodegradable microplastics and the influence on gut microbiota
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Researchers used a simulated human digestive system to study what happens to biodegradable microplastics when we swallow them. They found that PLA (polylactic acid) microplastics started breaking down in stomach acid, while PCL (polycaprolactone) microplastics stayed intact until reaching the large intestine, where both types disrupted beneficial gut bacteria. This is concerning because biodegradable plastics, often marketed as safer alternatives, may still harm gut health when ingested.
Oligomer nanoparticle release from polylactic acid plastics catalysed by gut enzymes triggers acute inflammation
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Researchers found that polylactic acid (PLA), a popular 'eco-friendly' biodegradable plastic, releases nanoplastic particles when broken down by gut enzymes during digestion. In mice, these PLA fragments accumulated in the liver, intestine, and brain, causing intestinal damage and acute inflammation by interfering with a key immune enzyme, raising important questions about whether biodegradable plastics are truly safer for human health.
Hepatotoxicity induced by polylactic acid microplastics: The mediating role of gut microbiota and uric acid metabolism
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Researchers found that polylactic acid (PLA) microplastics, often marketed as biodegradable and eco-friendly, caused liver damage in a study by disrupting gut bacteria and raising uric acid levels. The gut microbiome changes triggered by PLA microplastics were the key driver of the liver injury, not direct contact with the liver. This challenges the assumption that biodegradable plastics are safe and highlights the gut-liver connection in microplastic toxicity.
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When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.