A new TUBE study shows that the impact of diesel emissions on brain cells depends on the engine technology

Air pollution, mainly in areas with heavy road traffic, is increasingly linked to the development of a range of neurological diseases, including dementia. Ultrafine particles produced by diesel engines are especially considered to be dangerous, as they can penetrate the brain and activate inflammatory reactions. A new study by the international TUBE research team (open in a new window), published in the Environment International journal (IF 10.3), focused on how these particles affect human microglia cells derived from induced pluripotent stem cells.

Microglia are specialised cells of the central nervous system that mainly perform immune and support functions. They are part of glial cells called neuroglia. Unlike other glial cells (such as astrocytes and oligodendrocytes), which originate from nervous tissue, microglia develop from immune system cells.

The researchers analysed the effects of three types of emissions: from an engine burning conventional diesel (A20), from the same engine using renewable fuel (A0) and from a modern passenger car (E6) equipped with a diesel particulate filter and also using renewable diesel.

The results of the study, which also involved scientists from the Department of Toxicology and Molecular Epidemiology of the IEM CAS, are clear: ultrafine particles from engines without modern filtration (A20 and A0) significantly influenced gene expression in microglia, activating inflammatory signalling pathways and suppressing cellular repair mechanisms, especially autophagy. At the same time, they also impaired the function of lysosomes, which are cellular structures responsible for eliminating harmful substances. In contrast, particles from the modern engine (E6) did not change these cells’ function or genetic set-up even after 24-hour exposure.

The study also shows that human microglia are more sensitive to these particles than microglia from laboratory animals (mice), which shows that results derived from animal models may not always be fully applicable to humans.

The full results of the study are available in open-access mode on the Pubmed website (open in a new window).