Disruption of lipid metabolism under plastic siege: Unraveling the toxic mechanisms of microplastics and nanoplastics

Excessive production and discharge of plastics into the environment results in the production, accumulation, and toxicity of microplastics (MPs) and nanoplastics (NPs) in marine and terrestrial animals. This review aimed at evaluating the toxic effects of MPs and NPs on lipid metabolism and the mechanism behind disruptive potential. It is demonstrated that the exposure to these MPs and NPs affects the metabolic enzymes involved in absorption, metabolism and storage of lipids. These effects are demonstrated as dysregulation of lipogenesis, fasting-induced lipolysis, and glycolipids production. In the gastrointestinal milieu, exposure to MPs incites the inhibition of digestive enzymes and modulation of the composition of intestinal microflora. MPs and NPs exhibit oxidative stress-induced metabolomic toxicity in different animal species, in conjunction with lipotoxicity, hepatotoxicity, and disrupted steroidogenesis. Moreover, MPs instigate disruptions in glycolipid metabolism via the activation of the mitogen-activated protein kinase and nuclear factor kappa B signaling pathways in addition to suppression of nucleotide synthesis. Exposure to MPs and NPs results in the acute and chronic disturbances of lipid metabolism.