Study links increased levels of microplastics in urine to risk of endometriosis

A recent study published in the Ecotoxicology and Environmental Safety journal compares the presence of microplastics found in urine samples from healthy people and those with endometriosis.

Microplastics are synthetic polymer particles ranging in size from one micrometer (μm) to five millimeters (mm). They are widely distributed in the environment, including air, water, soil, and the food chain. Recently, microplastics have been detected in various human tissues and organs, such as the lungs, colon, liver, placenta, breast milk, testes, blood, urine, and stool.

Emerging evidence suggests that high levels of microplastic exposure may lead to inflammation and oxidative stress, which are core features of many chronic non-communicable diseases, including inflammatory bowel disease (IBD).

Endometriosis is a chronic inflammatory gynecologic disorder characterized by the presence of endometrial-like tissue outside the uterus. Although the exact etiology of endometriosis remains unclear, it is generally accepted that a complex interaction of genetic, environmental, hormonal, and immunological factors is associated with the development of this condition.

In the study, scientists assessed the presence of microplastics in urine samples collected from healthy individuals and patients with endometriosis. To do this, they used micro-Fourier transform infrared (μFTIR) spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX).

The analysis included 38 urine samples, of which 19 were from healthy donors and 19 from patients with endometriosis, as well as 15 pre-filtered water samples that served as procedural blank controls.

Analysis of urine samples from healthy donors revealed 23 microplastic particles consisting of 22 types of polymers in 17 samples. In urine samples from patients with endometriosis, 232 microplastic particles consisting of 16 types of polymers were detected in 12 samples.

The average level of microplastic particles in the urine of healthy donors was 2575 particles/liter, while in patients with endometriosis it was 4710 particles/liter. The most common polymer types in healthy donor samples were polyethylene (PE), polystyrene (PS), resin, and polypropylene (PP). In samples from patients with endometriosis, polytetrafluoroethylene (PTFE) and polyethylene (PE) were the most common.

The average length and width of microplastic particles in healthy donor samples were 61.92 and 34.85 μm, respectively. About 66% and 30% of the particles were fragments and films, respectively, and were clear or white in color.

The average length and width of microplastic particles in endometriosis patient samples were 119.01 and 79.09 μm, respectively. About 95% of the particles were fragments, 4% were films, and less than 1% were fibers. About 96% of the particles were clear or white.

Microplastic particles were found in urine samples from both healthy people and patients with endometriosis, and there were no significant differences in microplastic levels between the two groups.

High levels of PTFE fragments have been found in urine samples from patients with endometriosis. PTFE, also known as Teflon, is widely used as a non-stick coating and lubricant in cookware, car interiors and dental floss. In surgical applications, Teflon can cause Teflon granuloma, which is an inflammatory response of giant cells to exposure to PTFE fibers.

Further experiments are needed to determine the pathways of uptake and transport of microplastic particles throughout the human body and the health consequences of exposure to microplastics.