Impacts of microplastics on immunity

Abstract

Most disposable plastic products are degraded slowly in the natural environment and continually turned to microplastics (MPs) and nanoplastics (NPs), posing additional environmental hazards. The toxicological assessment of MPs for marine organisms and mammals has been reported. Thus, there is an urgent need to be aware of the harm of MPs to the human immune system and more studies about immunological assessments. This review focuses on how MPs are produced and how they may interact with the environment and our body, particularly their immune responses and immunotoxicity. MPs can be taken up by cells, thus disrupting the intracellular signaling pathways, altering the immune homeostasis and finally causing damage to tissues and organs. The generation of reactive oxygen species is the mainly toxicological mechanisms after MP exposure, which may further induce the production of danger-associated molecular patterns (DAMPs) and associate with the processes of toll-like receptors (TLRs) disruption, cytokine production, and inflammatory responses in immune cells. MPs effectively interact with cell membranes or intracellular proteins to form a protein-corona, and combine with external pollutants, chemicals, and pathogens to induce greater toxicity and strong adverse effects. A comprehensive research on the immunotoxicity effects and mechanisms of MPs, including various chemical compositions, shapes, sizes, combined exposure and concentrations, is worth to be studied. Therefore, it is urgently needed to further elucidate the immunological hazards and risks of humans that exposed to MPs.

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“…Perhaps sterile inflammation from microplastics is our closest analogy to sterile inflammation from a mutually mystified alien biology (Yang et al, 2022). It's broadly similar to other forms of sterile inflammation.…”

“…The reactive oxygen species, DAMP, inflammation and cell death are all detected but the other details need to be clarified. (Yang et al, 2022) First, coated microplastics (MP) shown in blue get taken up by the white blood cells (macrophages). The microplastics interfere with the mitochondria, the energy powerhouses of the cell that turn oxygen into energy.…”

“…The microplastics interfere with the mitochondria, the energy powerhouses of the cell that turn oxygen into energy. This leads to a build up of very reactive highly oxygenated chemicals like peroxides, perchlorates etc which leads to oxidative stress (Yang et al, 2022).…”

“…Next in response to the oxidative stress, the white blood cell may self destruct (apoptosis or programmed cell death) (Yang et al, 2022).…”

“…The DAMPs then may be activated by the damage to the white blood cell, which triggers an inflammation response. When the white blood cell breaks open, it may release the microplastics to start the process again (Yang et al, 2022).…”