No one wants to find out there’s plastic in their reproductive organs. Unfortunately, that may be a real possibility, according to Chelin Jamie Hu and a team of toxicology researchers from the University of New Mexico. Prior research has suggested connections between declining sperm counts and environmental factors, including industrial pollutants, pesticides, and endocrine disruptors. New findings from Hu and her team provide evidence for an additional factor: the microplastics that contaminate the world’s food, water, and air. Microplastics are small plastic particles that result from the breakdown of larger plastic pieces. These particles pose risks to human health, as research has linked microplastic exposure to a variety of issues such as respiratory and cardiovascular conditions, inflammatory responses, and hormone disruption. In a recent study, Hu and her team published preliminary findings showing microplastics in dog and human testes with potential associations with lower sperm counts.
Hu is a toxicologist at the University of New Mexico with nearly twenty years of experience studying reproductive development and endocrine-related disorders including breast cancer. Three years ago, she joined the lab of Xiaozhong Yu, an accomplished environmental reproductive toxicologist who focuses mainly on the chemical toxicity in the male reproductive system. Hu currently works as the lab manager. When she joined, the lab was already studying a specific compound of interest: BPA and its analogs. BPA is a component involved in plastic production that researchers have been concerned about for years because of its similarity to estrogen. As preliminary investigations of these toxic alternatives came out, Hu found the seed for her new work on plastics. All she needed was a specific physiological target.
Matthew Campen had been studying microplastics for years. His lab showed evidence of microplastics in human placenta and brain tissue, which suggested a greater exposure risk in these highly complex organs. Collaborating with Yu, he proposed that their work should focus on the male reproductive system. Male fertility has been well-recorded by researchers over many years, and a decline in fertility has been noted across the world. Their initial hypothesis was that the accumulation of microplastics could impact male fertility and reproduction.
The process for finding microplastics in human samples was relatively straightforward. Hu collected tissue from cadaver testicles and analyzed the tissue to see whether specific polymers were present using a method developed by the Campen Lab. She had already worked with dog tissue samples, comparing groups of dogs with higher or lower amounts of polymer accumulation in their testicles along with their sperm samples. Many other scientists had previously conducted research on microplastic accumulation, finding that people with more microplastic deposits in their artery plaque are at higher risk for cardiovascular events than those with fewer deposits. Additionally, people with chronic sinus infections have more microplastics in their noses, likely accumulated from breathing them in from the air.
Hu’s colleagues were united by a desire to share with others how environmental changes can impact human health in unexpected ways, hopefully encouraging action to limit the production of these harmful pollutants. “Our reproductive organs are what carry into the next generation,” Hu said. Given the mounting evidence demonstrating the harm that microplastics cause, Hu’s team wanted to make sure their results reached the public. “We just wanted to get that data out there because we think it’s quite a significant finding,” Hu said.
Hu’s sobering results exhibit the ongoing consequences of human-driven environmental pollution. “I’m a big culprit myself, obviously, but we need to be aware of the plastic waste we generate,” Hu said. In the United States, each person produces 1,800 pounds of waste per year. One million tons of plastic are deposited into the ocean yearly. Given that microplastics, along with their harmful side effects, are already being observed in major organs, we no longer have time to wait and hope for change. Hu is ready to do her part. Hopefully, her research can inspire people to action—or at least to fear for their testicles.