Deeply in Plasticenta: Presence of Microplastics in the Intracellular Compartment of Human Placentas

HIGHLIGHTS: What are the main findings? For the first time, microplastics were detected and localized by electron microscopy in human placentas. The presence of microplastics was correlated with ultrastructural alterations of some cell organelles in placental tissue, mainly in the syncytiotrophoblast. What is the implication of the main finding? Microplastics in human placentas could contribute to the activation of pathological traits, such as oxidat ive stress, apoptosis, and inflammation. Microplastics in human placentas may cause long-term effects on human health. ABSTRACT: Microplastics (MPs) are defined as plastic particles smaller than 5 mm. They have been found almost everywhere they have been searched for and recent discoveries have also demonstrated their presence in human placenta, blood, meconium, and breastmilk, but their location and toxicity to humans have not been reported to date. The aim of this study was twofold: 1. To locate MPs within the intra/extracellular compartment in human placenta. 2. To understand whether their presence and location are associated with possible structural changes of cell organelles. Using variable pressure scanning electron microscopy and transmission electron microscopy, MPs have been localized in ten human placentas. In this study, we demonstrated for the first time the presence and localization in the cellular compartment of fragments compatible with MPs in the human placenta and we hypothesized a possible correlation between their presence and important ultrastructural alterations of some intracytoplasmic organelles (mitochondria and endoplasmic reticulum). These alterations have never been reported in normal healthy term pregnancies until today. They could be the result of a prolonged attempt to remove and destroy the plastic particles inside the placental tissue. The presence of virtually indestructible particles in term human placenta could contribute to the activation of pathological traits, such as oxidative stress, apoptosis, and inflammation, characteristic of metabolic disorders underlying obesity, diabetes, and metabolic syndrome and partially accounting for the recent epidemic of non-communicable diseases.