Polyester Microfibers and Cardiomyopathy

Biology Capstone

So one of the primary things that we looked at to determine our expected results were figures from past studies similar to ours. In 2024, researchers in Naples, Italy conducted a study at the University of Campania weighing the effects of microplastics and nanoplastics on atheromas. Similarly, in 2022, a team of researchers observed the overall physiological health consequences of nano and microplastic exposure in rodent models. Essentially, we anticipate that exposure to polyester microfibers will impact cardiac health in ways similar to the effects observed from microplastics and nanoplastics in these studies.

So, what are some of the things that they found that we would also expect to observe? First off, we expect to greater levels of some of the previously mentioned biomarkers, IL-18, IL‑1β, IL‑6, and TNF‑α in subjects exposed to additional polyester microfibers than those in our control group. Figures A, B, C, and D are from the 2024 study, and you can see how concentrations of these biomarkers are generally much higher in patients with micro or nano plastic exposure.

A lack of collagen makes the plaque vulnerable to rupture, potentially causing restricted blood flow, inhibiting the heart from pumping blood effectively, or even contributing to something like a heart attack. We expect disruption in the cell signal transduction pathways that control collagen production in the rats treated with polyester microfibers because this was a notable trend in the similar studies we looked at that focused on microplastic and nanoplastic exposure.

Here, as you can see from the images and graphs in figures F and G, we expect increased levels of CD3 and CD68, which are molecules that can be used as markers of lymphocyte and macrophage infiltration, or in other words, the movement of those immune cells into tissues where they are not normally present in response to inflammation or disease.

Taking into consideration the findings from an alternative study on the consequences of microplastic exposure in rodent models, again, we predict similar results from exposure to the polyester microfibers. As you can see in this diagram, bioaccumulation of synthetic materials in the heart, increased oxidative stress, a rise in the rate of apoptosis and fibrosis of heart cells are all expected outcomes.

Firstly, microplastics can be difficult to identify.

Many scientists rely on electron microscopy to take images at tiny scales like the ones displayed above, but even then, differentiating microplastic, nanoplastic, and microfiber materials from other particles in the body can be a challenge. We have to rely on context clues like irregular shape or high-reflectivity of light to then be able to infer which particles are inorganic and potentially plastic materials. 

Panel A has black arrows pointing to particles with irregular shapes both inside a macrophage on the left and outside of a macrophage on the right.

Panel B also has black arrows to point out more irregularly shaped particles in the same specimen, as well as red boxes which mark small particles of high-reflecting material.

All 4 of these images indicate plastic materials in the arterial plaque of patients with atheromas.