| dc.description.abstract | An increasing number of plastics is produced each year, resulting into an increase of plastics ending up in our environment every year. The widespread use of plastics can be attributed to due to their easily accessible properties, such as durability, flexibility, lightweight nature, and more. These properties are often achieved through the incorporation of additives.
Most plastic additives are proven to have toxicities to biota and their addition can make the plastics more stable and so increase their persistence as pollutants. The exposure to plastics comes with risks for living organisms. Micro- and Nanoplastics (MNPs) are formed when larger pieces of plastics break down, this breakdown already occurs due to exposure of sunlight, the abrasion by waves and wind, and high temperatures, all processes occurring continuously. MNPs are present in even the most remote places on earth and have already been found within humans. MNPs can attach to red blood cells and so circulate within the body, potentially causing adverse health effects across multiple systems, such as the digestive, respiratory, endocrine, reproductive, and immune system. MNPs have already been found in human lungs, liver, intestines, blood, testis, and in the placenta. The placenta is a temporary organ with the main purpose to nourish and protect the fetus. Optimal working of the placenta is wanted to optimally provide the developing fetus with nutrients and oxygen. The exchange between mother and fetus is mostly done through chorionic villi. The outside of these villi are in direct contact with maternal blood and therefore important to facilitate the fetomaternal exchange. Plastics have been found to interfere with the functioning of the placenta, resulting in various pregnancy complications. Little research is present for the uptake or toxicity of MNPs in placental cells. The presence of MNPs in the placenta raises concerns for fetal development. This research is part of AURORA (Actionable eUropean ROadmap for early-life health Risk Assessment of micro- and nanoplastics). Their aim is to research early-life human health impacts from exposure to micro- and nanoplastics.
This thesis aims to localize the MNPs within the placenta and unravel their spatial distribution. This is done by examining pieces of placental cotyledon tissue perfused with 50-. 200-, and 1000 nm fluorescent polystyrene (FPS) particles. By achieving this localization, we can potentially get valuable insights about the behavior of MNPs within the placenta. A Hematoxylin & Eosin and fluorescence staining protocol have been developed to localize the FPS particles remaining in the tissue after perfusion. These particles have been found mainly around the outside of placental villi, where the exchange of nutrients and gases between mother and fetus takes place. No differences concerning locations have been observed among the 50-, and 200nm sizes of FPS. Some 1000nm particles have been found inside of the villi. Clustering of the 50- and 200nm particles has been observed. Indicating this may also happen in the body with naturally occurring nanoplastics of these sizes. Almost no transfer of particles from maternal to fetal circulation is found.
This research aims not only to contribute to the understanding of the impact of MNPs on early- life health, but also to provide some foundation for future research initiatives. Since MNPs continue to be in our environment, unraveling their dynamics within biological systems can result in knowledge necessary for the well-being of future generations. | |
