The world is littered with plastic. Microplastics (MPs) are found in almost everything, including our blood. According to scientists in a new study, that is particularly concerning given that the study found that though these pieces are small enough to flow easily through capillaries, their presence can clog blood vessels in the brain.
MPs are plastic particles with a diameter of less than 5 mm, originating from small plastic pellets produced for specific purposes, as well as from degradation, weathering and fragmentation of larger plastic products in the environment MP’s are ubiquitous worldwide, present in various environments; ranging from oceans and air to land and from Antarctic ice to human settlements Pollution from MPs is particularly notable in the oceans, where marine organisms such as fish, shellfish and plankton ingest them, thereby introducing them into the human food chain. Substantial amounts have also been found in freshwater systems, including rivers, lakes and reservoirs, allowing for contamination of human water sources.
The Research
To figure out what microplastics might do to brain tissue, researchers gave mice water laced with fluorescent plastic pieces and then watched through surgically implanted transparent windows for the glowing bits to show up in their brains. Not too long after the animals ingested the plastic, immune cells packed with the glowing particles showed up. These cells sometimes got stuck in tight curves of small blood vessels, which often caused more plastic-laden cells to get caught “like a car crash,” lead author Haipeng Huang told Nature. And although many of these pileups broke apart, some stayed put for the full four weeks of the experiment. Huang and his colleagues have spotted similar plastic-filled cell accumulations in other organs. The findings may help explain previous connections between microplastics, strokes and heart attacks. Nanoscale plastics can breach the blood-brain barrier, leading to neurotoxic effects. How MP’s cause brain functional irregularities remains unclear.
This study used high-depth imaging techniques to investigate MPs within the brain in vivo and showed that circulating MPs are phagocytosed, leading these cells to obstruction in the capillaries of the brain cortex. These blockages, as thrombus formation, caused reduced blood flow and neurological abnormalities in mice. The data revealed a mechanism by which MPs disrupt tissue function indirectly through regulation of cell obstruction and interference with local blood circulation, rather than direct tissue penetration. This revelation offers a lens through which to comprehend the toxicological implications of MPs that invade the bloodstream.
In this study, miniature two-photon microscopy (mTPM) was applied and imaged MPs in the mouse brain in vivo while the animal was awake. With the high-depth imaging capability, it observed MPs in the blood vessels of the mouse cerebral cortex. These scientists also tracked the high-speed movement of MP particles in the blood vessels, revealing a mechanism by which MPs can induce brain dysfunction and neurological impairment.
Effects on Human Health
In addition, MP particles can be transported through the atmosphere and disseminated into the air, eventually entering the human respiratory system. Other recent studies have indicated that MPs can directly enter the human bloodstream through the use of plastic medical supplies. It has also been found
in human faeces and various tissues, including the liver, kidney, placenta and blood. Accumulation of MPs in organisms can further result in tissue dysfunctions and chronic diseases such as respiratory diseases, immune system disorders, chronic inflammation, endocrine gland effects leading to hormone imbalance and metabolic dysfunctions In particular, the presence of MPs in the bloodstream poses a substantial health challenge. As the blood circulates, these MPs may be carried to any organ, especially the distal branch vessels. Studies have shown that blood MPs can lead to acute cardiovascular diseases
Furthermore, patients with carotid artery plaque in which MPs and nanoplastics (NPs) were detected, had a higher risk of a composite of myocardial infarction, stroke, or death from any cause in 34 months. These potential threats can be life-threatening compared to the chronic diseases caused by MPs. MPs can also cause brain dysfunction. Nano sized plastic particles can penetrate the blood-brain barrier (BBB) and enter brain tissue. The interaction between NPs and a-synuclein fibrils can exacerbate the spread of a-synuclein pathology in vulnerable brain regions, potentially triggering or worsening conditions such as Parkinson’s disease and other neurologically related dementia diseases.
However, how micron-sized plastics affect brain function remains unclear. Several studies have proved that treatment with MPs affects behaviour and induces phenotypes such as anxiety in mice. It is supposed that micron-sized plastics break down into nanosized plastic particles in the body and then enter the brain to exert their effects. It has also been suggested that the impact of MPs on the brain may be mediated through their effects on peripheral tissues, including the modulation of immune inflammation and glycolipid metabolism. What the manner by which MPs affect the brain and the mechanisms that they exert their effects remain uncertain.
The development and innovative application of previously unknown research techniques often open new avenues, providing researchers with fresh perspectives and facilitating a deeper understanding of scientific principles.
