Brain Tissue Accumulation

A study conducted by researchers at the University of New Mexico, published in Environmental Science & Technology, examined brain samples from human autopsies performed in 2016 and 2024. The results paint a worrying picture of microplastic accumulation in the human brain over time:

2024 Brain Samples:

• Average concentration: 4,806 μg of microplastics per gram of tissue (0.48% by weight)
• Highest recorded concentration: 8,861 μg/g
• Range: Approximately 1,000 to 8,861 μg/g

2016 Brain Samples:

• Average concentration: 3,057 μg/g
• This represents a 57% increase in just 8 years

Overview of total MNP concentrations from all decedent samples from liver, kidney, and brain

Comparison to Other Organs (2024 data):

• Liver: 465 μg/g
• Kidney: 666 μg/g
• Brain concentrations were 7.2 to 10.3 times higher than liver or kidney

Polymer Composition:

• Polyethylene was the predominant plastic type:
  • 74% of microplastics in brain samples
  • 44-57% in liver and kidney samples
• Other polymers detected included polyvinyl chloride, nylon, styrene-butadiene, and polystyrene.

Nanoscale Particles: A New Concern

Transmission electron microscopy (TEM) revealed the nature of these particles:

• Many particles were shard-like in appearance.
• Sizes ranged from micrometer to nanometer scale.
• A significant portion were less than 200 nm in length.

This nanoscale size is particularly concerning as it may explain how these particles can cross the blood-brain barrier, a notoriously selective membrane that protects the brain from many harmful substances.

Microplastics in Other Human Tissues

The study adds to a growing body of research detecting microplastics in various human tissues:

Placenta:

• Average concentration: 126.8 ± 147.5 μg/g
• Range: 6.5 to 685 μg/g
• Polyethylene was most prevalent, accounting for 54% of total microplastics.
• Mean polyethylene concentration: 68.8 ± 93.2 μg/g

Bone Marrow:

• Average concentration: 51.29 μg/g
• Range: 15.37 to 92.05 μg/g
• Five polymer types identified: polyethylene, polystyrene, polyvinyl chloride, polyadiohexylenediamine 66, and polypropylene.
• Polyethylene was most frequent, with an average concentration of 30.02 μg/g (range: 14.77 to 52.57 μg/g).
• 89.82% of particles were smaller than 100 μm.

Seminal Fluid:

• Average: 2 particles per sample
• Size range: 0.72 to 7.02 μm
• Eight distinct polymers identified, with polystyrene being most prevalent (31%).

Potential Health Risks: A Deeper Dive

While the full health implications of microplastic accumulation in human tissues are not yet fully understood, research is uncovering several areas of concern:

Oxidative Stress:

• Microplastics increase production of reactive oxygen species (ROS) in cells.
• This can lead to lipid peroxidation, DNA damage, and altered enzyme activity.
• In a study on mice, polystyrene microplastics (0.5 and 5 μm, 10 mg/L) decreased activity of antioxidant enzymes like superoxide dismutase, glutathione peroxidase, and catalase in liver tissue.

Inflammation:

• Animal studies show microplastic exposure can trigger inflammatory responses.
• In mice intestinal tract, polypropylene particles (8 and 10 μm, 0.1-10 mg/mL) increased levels of malondialdehyde and activated the TLR4/NFκB inflammatory signaling pathway.

Cellular Disruption:

• Nanoplastics may interfere with normal cellular functions, particularly in the brain.
• In vitro studies on human cells showed polystyrene particles (0.1-5 μm, 20-200 μg/mL) can induce mitochondrial dysfunction and alter gene expression related to oxidative stress.

Reproductive Health:

• In mice, polystyrene microplastics (0.5, 4, and 10 μm, 1 mg/day) led to:
  • Decreased testosterone levels.
  • Abnormal sperm morphology.
  • Inflammatory reactions in testicular tissue (increased TNF-α and IL-6).
• Human studies found microplastics in all semen samples tested, with potential impacts on sperm motility.

Neurodegenerative Concerns:

The study authors noted parallels between increasing brain microplastic concentrations and rising global rates of age-corrected Alzheimer's disease and related dementias. While causation is not established, the potential link warrants urgent investigation.

Methodological Advancements

The study employed pyrolysis gas chromatography-mass spectrometry (Py-GC/MS), a novel analytical chemistry method that allows for more comprehensive detection of micro- and nanoplastics:

• Can detect particles as small as 1 nm.
• Analyzed 12 specific polymers in this study.
• Within-sample coefficient of variation of approximately 25%.

This method represents a significant advancement over previous visualization and spectroscopic methods, which were often limited to larger (>1–5μm) particulates.

Conclusion and Call to Action

These findings underscore the urgent need for further research into the long-term health impacts of microplastic accumulation in human tissues. The study reveals not only the presence of microplastics in the brain but also a disturbing upward trend in concentrations over time.

As Dr. Matthew Campen, lead author of the study, stated, "The parallels between the present data showing an increasing trend in microplastic concentrations in the brain with exponentially rising environmental presence of microplastics and increasing global rates of age-corrected Alzheimer's disease and related dementia add urgency to understanding the impacts of microplastics on human health."

This research serves as a stark reminder of the far-reaching consequences of our reliance on plastic materials. It calls for immediate action on multiple fronts:

Steps you can take

Avoid consuming products wrapped in plastic as much as possible which includes fast food, snacks and leftovers.

Also stay away from plastic water bottled and get a filter that removes microplastics which you can search on Oasis.

As we continue to uncover the extent of microplastic pollution in our bodies and our environment, it becomes increasingly clear that this is not just an environmental issue, but a potential public health crisis of global proportions.