Nanoplastics have been found to disrupt growth

25 nm PS-NPs induce cardiac malformations by disrupting cardiac neural crest development. ap, CT scans of hearts and great vessels at 8 dpe. ah, control embryo, stage 35. n = 2. a and e, segmentation and volume rendering of heart and vessels. (b, d, g), virtual cross-sections. (c, h) two-dimensional (2-D) view of virtual cross-sections. (f), three-dimensional (3-D) model of large vessels produced by manual tracing. (ip), PS-NP treatment, stage 35. n = 2. (i, m), PS-NP-treated heart volume yield. (n), 3D model of large vessels produced by manual tracing. (j, n, o), 3D view of virtual cross sections. (k, p), 2-D view of virtual cross sections. (q, r), whole-mount in situ hybridization of TFAP2A. (q), control embryo, stage 19. n = 2. (r), PS-NPs-treated embryo, stage 18. n = 3. sv, immunohistochemistry showing transverse sections stained with TFAP2A and DAPI. n = 2 for control and n = 5 for PS-NPs-treated group. (s, t), control chick embryo, stage 19. (u, v), PS-NPs-treated chick embryo, stage 17. Note, the heart treated in (ip) has a ventricular septal defect ( arrowhead) and supernumerary pharyngeal arch arteries (seven instead of the normal five). The two supernumerary pharyngeal arteries (green and blue) are anomalous subclavian arteries. In this fetus, the brachiocephalic artery is abnormally short. The arteries of the sixth pharyngeal arch are normal in all our specimens from the control group. Complete in situ hybridization for the cardiac neural crest marker TFAP2A shows that PS-NP treatment causes failure of the cardiac neural crest to fully fill the pharyngeal arches. It also disrupts cardiac neural crest migration so that some crest cells never leave the neural tube (arrows). Key: purple, right aorta. red, right brachiocephalic artery; yellow, left pulmonary artery. pink; left brachiocephalic artery. blue, right pulmonary artery; green right subclavian artery. light blue, left subclavian artery. PS-NP, embryos treated with polystyrene nanoparticles (25 nm, 5 mg/mL). dpe, days post-exposure. Scale bars, 500 μm in (ap), 300 μm in (q, r), 200 μm in (s, v). (For interpretation of color references in this figure legend, the reader is referred to the web version of this article.). Credit: Environment International (2023). DOI: 10.1016/j.envint.2023.107865

Nanoplastics cause malformations. This is the conclusion of Meiru Wang, a researcher at the Leiden Institute of Biology, who examined the extreme effects that polystyrene nanoparticles could have, using chicken embryos as a model.

“We see malformations in the nervous system, heart, eyes and other parts of the face,” says Wang. “We used a high concentration of polystyrene particles, which would not normally be present in an organism. But it shows what nanoplastics can do in extreme cases to very young embryos. And it also gives us clues as to what can happen less severely in the developing stage,” says Wang.

The results are now published on Environment International.

Nanoplastics target stem cells

The nanoplastics target embryonic neural crest cells, Wang found. These stem cells form very early in all vertebrates at the beginning of their existence. Neural crest cells start in what will be the spinal cord and migrate to form part of the nervous system. They are also parts of many important organs, such as the arteries, the heart, and the face.

However, when the nanoparticles surround neural crest cells, the migration of these cells is disrupted. This results in growth disorders.

Michael Richardson, Wang’s supervisor, says: “Once you know the mechanism, everything else falls into place. We think they stick to neural crest cells, which causes the cells to die. Neural crest cells are sticky, so the nanoparticles can attach to them and thus disrupt the organs that depend on these cells for their growth. I like the transfer of dough. When you make bread, for example, you add flour so that it doesn’t stick anymore. However, in this case , destroys the migration of the neural crest cells’.

Finding mechanisms with 3D reconstructions, x-rays and expertise

The research project involved several research centers in Leiden and abroad, including the CML, whose new director, Martina Vijver, is Wang’s supervisor. “Because nanoplastics are so small, they’re impossible to see using conventional microscopes. That’s what makes research difficult. We can only see them when they’re fluorescently labeled,” Richardson explained. “Collaboration was the way to go, as this kind of research cannot be done as a one-man band.”

The researcher continues, “At the Naturalis Biodiversity Center in Leiden, Martin Rücklin and Bertie Joan van Heuven were able to make three-dimensional reconstructions of the embryos so that we could clearly see the malformations. And with the high-resolution synchrotron Switzerland, we could see what happens in the heart. Experienced researchers from LUMC helped define what we saw.”

Wang is very happy with her research, even with its troubling results. “Everything is a question mark in research and you have the opportunity to fill in the blanks. I have many great supervisors and colleagues, who encourage me and make me braver. This research is only one step to see what the final results are nanoplastics in our environment. And especially as people are now looking at their use in human medicine, we think we need to be careful before these drastic effects are seen in humans.”

More information:
Meiru Wang et al, Nanoplastics cause extensive congenital malformations during embryonic development by passively targeting neural crest cells, Environment International (2023). DOI: 10.1016/j.envint.2023.107865

Provided by Leiden University

Reference: Malformations in the heart, eyes and nervous system: Nanoplastics found to disrupt development (2023, March 13) Retrieved March 13, 2023, from heart-eyes-nervous-nanoplastics. html

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