Advances on mechanisms of abnormal glucose metabolism induced by ambient fine particulate matters

Recently, the adverse health effects of air pollution have become increasingly concerned. Ambient fine particulate matters (with aerodynamic diameter ≤ 2.5 μm, PM_2.5) can deposit in the lower airway, and even enter the pulmonary alveoli, causing multiple adverse health effects. A large number of epidemiological studies have indicated that ambient PM_2.5 exposure is a crucial risk factor for diabetes. Diabetes is a chronic metabolic disease characterized by insulin resistance and/or insufficient insulin secretion under genetic and environmental interactions. The morbidity of diabetes in China has increased dramatically from 3.3% in 1990 to 6.6% in 2016, and the situation is serious with diabetes patients ranking the first place in the world. Since the underlying biological mechanisms are not fully elucidated, this review summarized recent research on the potential mechanisms of ambient PM_2.5-induced abnormal glucose metabolism. In addition to inflammation reaction, oxidative stress, endoplasmic reticulum stress, and activation of nuclear factor κB (NF-κB) signaling pathway, gut microbiota-related pathways, especially the mediation roles of microbial metabolic products such as short chain fatty acids, bile acid metabolism, endotoxin metabolism, and change of intestinal permeability were also discussed in detail, aiming to provide scientific evidence for the propose and establishment of novel intervention methods and measures against abnormal glucose metabolism induced by PM_2.5.