Nanoplastics affect the composition and diversity of the human intestinal microbiome

We live in a world plagued by plastic. Its role as a stable, multifunctional and multifunctional chemical encouraged its widespread use, which has ultimately translated into our current state of planetary pollution.

In addition, as plastic decomposes it breaks down into micro and smaller nanoparticles, becoming present in the water we drink, the air we breathe, and almost everything we touch. This is how nanoplastics pass through the organism and produce side effects.

A revised study led by the Universitat Autónoma de Barcelona (UAB), the CREAF and the Center for Environmental and Marine Research (CESAM) at the University of Aviero, Portugal, and published in the journal Journal of Science, confirming that the nanoplastics affect the composition and diversity of our intestinal tract and that this can damage our health.

This effect is seen in both spinal and invertebrate bones and has been proven in situations where the exposure is widespread and prolonged.

In addition, changes in the gut microbiome lead to changes in the immune, endocrine, and nervous systems, and so, although not enough is known about the specific psychological mechanisms, the study warns that stress to the gut microbiome could alter human health.

The health effects of exposure to nanoplastics have traditionally been evaluated in aquatic animals such as molluscs, bark beetles and fish. Recently in vitro analyzes, using fish cell cultures and mammals, have allowed scientists to analyze the changes in gene expression associated with the presence of nanoplastics from a toxic perspective.

Most of the neurological, endocrine and immunological pathways in these spines are very similar to those of humans, so authors warn that some of the effects observed in the these models to be applied in humans.

It is fundamental to understand and study the process by which these plastic particles pass through the organism and damage it, and also to determine the size and composition of nanoplastics that are polluting the environment.

For this reason, researchers point out that not only do the specific mechanisms and effects on human cell models need to be further studied, but also integrate research methods to accurately measure the size of the cells. nanoplastics present in various ecosystems.

Mariana Teles, a researcher at the UAB, in collaboration with other researchers such as Josep Peñuelas, a CSIC lecturer at the CREAF, says “this article is not aimed at building the alarm, but it tries to warn that plastic can be found in almost everything around us, it does not separate and we are always open to it. At this time, we can only speculate on the long-term effects this may have on human health, although we already have evidence in several studies describing hormonal and immune changes in fish exposed to nanoplastics, and potentially applied to humans ”.

Aggressive and poisonous

The study covers the main environmental sources through which nanoplastics enter the human body and summarizes how they can enter the body: by taking them inhaling, inhaling them, and very rarely in contact with human skin.

Once ingested, up to 90% of the plastic particles that reach the intestine are excreted. However, one part is separated into nanoplastics which, due to their small size and molecular properties, are able to penetrate the cells and cause adverse effects.

The study establishes that changes in food intake were explained, as well as inflammatory reactions in the intestinal walls, changes in the production and activity of the gut midges, effects on metabolism and body capacity to, and finally, effect changes in immune responses. .

The article warns of the possibility of long-term exposure to plastic, accumulated through the generations, which may lead to incomprehensible changes even in the real genome, as has been seen in some animal models.

The team of which Mariana Teles (Evolutive Immunology Group, IBB-UAB) is a member also recently published an analysis of the effects of nanoplastics in fish.

The study, which is the result of a Ph.D. a dissertation led by Nerea Roher, was published in Environmental Science: Nano and studying the impact of exposure to nanoplastics to the zebrafish immune system (a small tropical fish widely used as an organism model for research).

The scientists conclude that the nanoplastics can accumulate both in the cells and in the embryos of the zebrafish, moreover causing changes in the levels of genes relevant to the proper functioning of the immune system the animal. Despite this, the knowledge of nanoplastics did not affect the ability of zebrafish embryos to survive bacterial infection.

The team of researchers nevertheless rejects the need to continue research in this area, as the presence of microplastics and nanoplastics in our ecosystems is a critical environmental issue. ‘answers are needed to understand how wide it can be.

Responsible practice

The review study acknowledges that various methods of removing nanoplastics from the water are being tested, such as filtration, centrifugation and flocculation of waste water, and water-water treatment.

Although the results are promising, they are limited to handling larger pieces of plastic, so to date no effective solution has been found for the removal of nanoplastics from the environment.

To solve this problem of plastic pollution, human practices need to change and policies should be based on informed decisions about the known hazards and available alternatives. Individual actions such as the use of more environmentally friendly materials and an increase in recycling records are important. “

Mariana Teles, Researcher, Universitat Autónoma de Barcelona

“Authorities can promote these pro-environmental activities through economic incentives, such as tax benefits for reusing plastics as industrial raw materials, as well as consumer bottle investment schemes,” researchers say. ‘praise.