Microplastics found to obstruct brain blood vessels in troubling neuroscience study

[Sly Saint]

A new study published in Science Advances has uncovered a previously unknown mechanism by which microplastics can disrupt brain function. Using high-resolution in vivo imaging, researchers observed that microplastics in the bloodstream are engulfed by immune cells, which then become trapped in the brain’s capillaries. These obstructions reduce blood flow in the brain and lead to neurological impairments in mice. The findings provide an important new perspective on how plastic pollution may threaten human health, particularly through impacts on the vascular system and brain.

Studies have already detected microplastic particles in human blood, lungs, placenta, and feces. More recently, scientists found nanoplastics, which are even smaller than microplastics, capable of crossing the blood-brain barrier. But how microplastics might impair brain function without passing into brain tissue has remained unclear.

To investigate this question, the research team—led by Haipeng Huang, Jiaqi Hou, and Beidou Xi of the Chinese Research Academy of Environmental Sciences—employed advanced two-photon imaging techniques to examine how microplastics behave inside the brains of living mice. Collaborators from Peking University, Duke University, and the National University of Singapore contributed to the study.

The researchers introduced fluorescently labeled polystyrene microplastic particles into mice by either oral administration or direct injection into the bloodstream. The particles were about 5 micrometers in diameter, which is similar in size to those found in real-world human exposure. The team then used in vivo imaging to track how the particles moved through cerebral blood vessels.

They discovered that after entering the bloodstream, the microplastic particles were engulfed by immune cells, particularly neutrophils and macrophages. These immune cells, now carrying the plastic particles, circulated through the blood and occasionally became lodged in tiny brain capillaries. The researchers referred to these plastic-bearing immune cells as MPL-cells. In many cases, MPL-cells became permanently stuck in the vessels, with some remaining for up to a week.

MSN