News 21 May 2024

Study finds microplastics in every human testicle sample

21 May 2024

Microplastics have been discovered in human testicles, a finding researchers believe may be linked to declining sperm counts in men.

In a recent study, scientists examined 23 human testes and 47 testes from pet dogs, uncovering microplastic contamination in every sample.

The preserved human testicles could not be used to measure sperm counts, but in the dogs, higher contamination with PVC corresponded with lower sperm counts. Although this study suggests a correlation, further research is necessary to confirm if microplastics are directly responsible for reduced sperm counts.

For decades, men’s sperm counts have been declining, with various studies pointing to chemical pollution, such as pesticides, as a potential cause. Microplastics, which have been found in human blood, placentas, and breast milk, are increasingly recognised as pervasive contaminants. While the exact health impacts remain unclear, laboratory tests show that microplastics can damage human cells.

Microplastics have infiltrated the environment extensively, from the peak of Mount Everest to the ocean depths. People ingest these particles through food, water and even air. Similar to air pollution particles, microplastics can lodge in tissues and cause inflammation or release harmful chemicals. In March, doctors highlighted severe health risks, including increased chances of stroke, heart attack and premature death, linked to microplastic contamination in blood vessels.

“I initially doubted that microplastics could penetrate the reproductive system,” said Prof. Xiaozhong Yu from the University of New Mexico. “I was surprised by the results in dogs and even more so by the findings in humans.”

The human testes, obtained from postmortems of men aged 16 to 88, had nearly three times the plastic concentration of the dog testes: 330 micrograms per gram of tissue compared to 123 micrograms. The most common microplastics found were polyethylene, used in plastic bags and bottles, and PVC.

“PVC releases chemicals that disrupt spermatogenesis and cause endocrine disruption,” Yu explained. The human testes were collected by the New Mexico Office of the Medical Investigator and analysed after their mandatory seven-year storage period.

This study, published in Toxicological Sciences, follows a smaller 2023 Chinese study that found microplastics in six human testes and 30 semen samples. Additionally, recent research in mice has shown that microplastics reduce sperm count and cause hormonal and reproductive abnormalities.

[Image created via MidJourney]