Microplastics Detected in Human Penis for the First Time

Tiny fragments of plastic waste have been detected in human penile tissue for the first time, raising new questions about how environmental pollutants may affect sexual and reproductive health.

The study, published in the International Journal of Impotence Research, was led by scientists at the University of Miami, Florida.

Growing concerns surrounding microplastic contamination

Microplastics (MPs) are incredibly small fragments of plastic waste that measure up to 5 mm in size. Over recent years, these emerging contaminants have garnered significant attention due to their potential impact on the environment and our health. Though this research field remains in its infancy, the detection of MPs in remote corners of the world, and in human tissues, has sparked concern.

Ranjith Ramasamy, MD, director of Reproductive Urology and associate professor at the University of Miami in Florida, led the new study that aimed to assess the aggregation of MPs in penile tissue.

“MPs, owing to their small size yet large surface area, can engage in chemical interactions with physiological fluids and tissues, raising concerns about their persistence, bioaccumulation and potential toxicity,” the study authors described. “Their ability to carry pathogens and pollutants further amplifies these concerns.”

The research team analyzed tissue samples from six individuals who underwent inflatable penile prosthesis, or IPP, for the treatment of erectile dysfunction (ED) between August–September 2023. One of the six samples was handled with standard sample collection methods, whereas the remaining five were collected using a specific protocol to prevent cross-contamination with MPs.

“Investigations into the role of MPs within the male reproductive system represent a recent area of inquiry, with limited existing literature,” Ramasamy and colleagues said. “Much of the existing research has been predominantly focused on the impact of MPs on male infertility.”

Microplastics detected in all penile tissue samples

Two key techniques were used to assess MP presence: laser direct infrared imaging (LDIR), which enables scientists to rapidly analyze up to 1,000 particles or fibers that are less than 300 μm in size, and scanning electron microscopy (SEM).

“One of the notable strengths of this study lies in its comprehensive methodology, incorporating both quantitative and qualitative approaches,” the researchers said. “By utilizing both LDIR for qualitative data in conjunction with SEM for quantitative information, a greater understanding of the various permutations and characteristics of MPs in the penile tissue samples was achieved.”

MPs were detected in 80% (4 out of 5) samples. Polyethylene terephthalate (PET) and polypropylene (PP) – two common MPs that are found in many household products and packaging – were the most prevalent MPs, making up 82% of the total MPs detected across the samples. “MPs were found in the one control sample, with poly methyl methacrylate being the sole MP specific to this sample,” Ramasamy and colleagues said.

The study sample is small – a limitation that must be considered. It also establishes a correlation, not causation, which means the research team cannot conclude that ED is associated with the presence of MPs. However, the study results “offer valuable insights that enrich the ongoing discussions on the intricate interactions between MP and human tissues,” the authors said.

Additional studies, exploring how MPs might affect human reproductive tissues in vivo, are warranted.

Reference: Codrington J, Varnum AA, Hildebrandt L, et al. Detection of microplastics in the human penis. IJIR. 2024. doi:10.1038/s41443-024-00930-6