Polystyrene-induced changes in adipose transcriptome

Microplastics (MP) derived from the weathering of polymers, or synthesized
in this size range, have become widespread environmental contaminants and
have found their way into water supplies and the food chain. Despite this
awareness, little is known about the health consequences of MP ingestion.
We have previously shown that the consumption of polystyrene (PS) beads
was associated with intestinal dysbiosis, diabetes, and obesity in mice.
To further evaluate the systemic metabolic effects of PS on the
gut-liver-adipose tissue axis, we supplied C57BL/6J mice with normal water
or that containing two sizes of PS beads (0.5mm and 5mm) at a
concentration of 1mg/ml. After 13wk, we evaluated several indices of
metabolism and liver function. As previously observed, mice drinking the
PS-containing water had a potentiated weight gain and adipose expansion.
Here we found that this was associated with an increased abundance of
adipose F4/80+ macrophages. These exposures did not cause non-alcoholic
fatty liver disease (NAFLD) but were associated with decreased liver:body
weight ratios and an enrichment in hepatic FXR and LXR signaling. PS also
increased hepatic cholesterol and altered both hepatic and cecal bile
acids. Mice consuming PS beads and treated with the berry anthrocyanin,
delphinidin, demonstrated an attenuated weight gain compared to those mice
receiving a control intervention and also exhibited a down-regulation of
cAMP and PPAR signaling pathways. This study highlights the obesogenic
role of PS in perturbing the gut-liver-adipose axis and altering nuclear
receptor signaling and intermediary metabolism. Dietary interventions may
limit the adverse metabolic effects of PS consumption.