In an article published on September 26, 2023, in the journal Chemosphere, Jan Halfar from the Technical University of Ostrava, Czechia, and co-authors detected microplastics and plastic additives in the placenta and amniotic fluid of nine out of ten women who gave birth prematurely.
All the women experienced physiological, singleton pregnancies complicated with preterm prelabour rupture of membranes (PPROM) between 24 and 36 + 6 weeks of gestation. The scientists analyzed samples of their placenta and their amniotic fluid not only for microplastics by Fourier transform infrared spectroscopy but also for microbial invasion and intra-amniotic inflammation (level of interleukin 6).
The authors detected microplastics or additives in nine of the ten patients. The average number of particles in the amniotic fluid was 1.5 while it was 2.8 for the placenta samples. Particle sizes ranged from 49.5 to 46,372 μm2. The paper is missing details on which additives were analyzed and by what methods, but the researchers stated that they identified a total of “11 particles of microplastics and 17 of polymer additives” in the placenta samples.
While previous studies have reported the presence of microplastics in the human placenta (FPF reported and here), Halfar and co-authors are the first to report on their presence in amniotic fluid. They clarified that their study does not allow making any association between microplastics’ presence and PPROM but noted that “the mechanisms through which microplastics traverse the placenta and their effects on the human body warrant further investigation.” Previously, scientists found microplastics affect offspring (FPF reported and here).
Besides in female reproductive organs, microplastics can also be present in male reproductive organs. The small plastic particles were detected in human semen as well as in testis (FPF reported) and in mice, it was demonstrated that they can affect male reproductive health (FPF reported and here).
In an article published on August 28, 2023, in the journal Particle and Fibre Toxicology, Deyi Wu from Jilin Agricultural University, Changchun, China, and co-authors evaluated the impact of polystyrene (PS) microplastics on premature testicular aging in vitro using testicular Sertoli cells (TM4 cells) and in vivo using 8-week-old C57 mice.
Exposing TM4 cells to three concentrations of spherical PS microplastics and assessing a set of cellular aging markers, Wu and co-authors found the particles resulted in the premature senescence of the cells. They further investigated the underlying molecular mechanism and identified NF-kB as a key molecule whose activation was triggered by reactive oxygen species (ROS). Ca2+ again was found to be the responsible factor for the accumulation of ROS in the mitochondria. Therefore, the authors concluded that polystyrene microplastics “caused testicular premature aging [which] is dependent on Ca2+/ROS/NF-κB signaling axis.”
The scientists also assessed aging markers in 8-week-old C57 mice upon exposure to 1 mg/kg or 5 mg/kg particles for four weeks. The results confirmed their in vitro findings that PS microplastics’ exposure “causes premature aging of testicular tissue” in addition to the particle-induced oxidative stress and inflammatory response in the tissue.
References
Halfar, J. et al. (2023). “Microplastics and additives in patients with preterm birth: The first evidence of their presence in both human amniotic fluid and placenta.” Chemosphere. DOI: 10.1016/j.chemosphere.2023.140301
Wu, D. et al. (2023). “Long-term exposure to polystyrene microplastics triggers premature testicular aging.” Particle and Fibre Toxicology. DOI: 10.1186/s12989-023-00546-6
