Diesel particles attack the liver function
Allowing the body to eliminate certain toxic elements, the liver plays a vital role in the human body. A study has shown that diesel particulate disrupt its detoxifying liver function by blocking certain carriers. The health implications are not yet well known. This could include enhancing the carcinogenic effects of diesel related to oxidative stress.
Diesel station! The fine particles are not only toxic to the lungs, but they are also able to cross the lung barrier and attack other organs. He had indeed been shown that these particles alter the function of certain liver enzymes. A new study shows this time they can also impair the liver's detoxification function, that is to say its ability to sort and eliminate toxic waste to the body.
The origin of this discovery researchers (Inserm Unit 1085, research institute Health, environment and labor, Rennes) worked in vitro on liver cells (hepatocytes) in culture. They have them exposed to extract particles from combustion of a diesel engine (DEP Diesel exhaust particles) at doses equivalent to those inhaled by an individual living in a polluted environment. The researchers then measured the level of expression and activity of several carriers at the cell surface. Their findings appear in the journal Plos One.
These hepatic transporters ensure the passage of molecules circulating in the blood to the inside of the liver. Bile then led to the elimination of these substances. The whole system allows the body to get rid of natural waste products from the cells, medicines or drugs. However, the authors found that DEP reduces the expression of genes encoding these transporters and block the activity of several of them. The phenomenon is observed when the cells are exposed to low levels of particles.
The MRP2 and OATP transporters inhibited
In particular, researchers found a strong inhibition of MRP2 and OATP transporters involved in the hepatic elimination of many toxic drugs, but also in that of sex steroid hormones and thyroid hormones. Blocking the activity of MRP type carriers could also disrupt control circuits of glutathione, an important endogenous antioxidant molecule.
At this point, even if it comes to work in vitro, the spectrum of clinical consequences envisaged by the authors is wide: endocrine disruption, disturbance elimination of drugs and endogenous metabolites or excessive oxidative stress to poor elimination of free radicals, which can contribute to the development of chronic diseases. "This would include the effect of strengthening the carcinogenic effects of diesel favored by oxidative stress," says Olivier Fardel, co-author of this work to the research institute on health, the environment and labor.
Assumptions that drive to continue this work: for example, the authors wish to look towards the carriers present in the pulmonary cells (some of which are similar to those found on hepatocytes), focusing in particular on carriers associated with carcinogenesis. They count as precisely identify chemical molecules involved in the inhibition of transporters in the cocktail particles used in the context of their work. Finally, they want to extend their studies to potential interactions of membrane transporters with other chemical pollutants.
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