Over the past three decades, the number of Parkinson’s cases has nearly tripled worldwide. If this trend does not change, in less than 20 years it will double again. However, little is known about the risk factors for this neurological disease. A team of specialists pointed to a chemical product that was very common until recently, trichlorethylene, used as an industrial degreaser but also present in stain removers or liquid typographic correctors – known as ‘typex’ by the most famous of them, as the possible culprit. Tipp-Ex–, and asks to completely eliminate its use.

This product has been used for over a century, but only recently has its presence begun to be limited: the European Union classified it as a potential carcinogen in the last decade and restricted its use in 2016. Today, production on the continent is around 300 tons per year, far from the 50,000 in 2010, but worldwide its volume is growing at a rate of 3% per year.

Therefore, experts from the departments of Neurology at the universities of Rochester, Alabama (United States) and Radboud (Holland) published an article in the medical journal Parkinson’s Disease Journal in which they review the evidence linking trichlorethylene to neurological disease and threatening its demise.

[Los síntomas tempranos del párkinson: así comienza a manifestarse la enfermedad]

“He [producto] chemist has a century of life. We don’t fly planes or drive cars like the Wright brothers or Henry Ford did, engineers developed safer models. Chemists can do the same with solvents.”

Trichlorethylene is a colorless, non-flammable, sweet-smelling liquid that evaporates quickly into the air. Today it is mainly used to clean industrial machines, although it also finds its place in the production of soft drinks, paints and even dry cleaning.

On a commercial level, it is present in stickers, cleaning products, stain removers, varnishes and typographic correction fluids. However, in the past its use has come to be associated with pesticides, glues, paints, disinfectants, anesthesia and even the production of decaffeinated coffeealthough it ceased to be used for these last two functions in the 1970s, when it was “ubiquitous” in the US, explain the authors of the article.

[Estos son los dos nuevos síntomas tempranos que se relacionan con el párkinson]

At that time, the first suspicion of its relationship with Parkinson’s arose, when the case of a 59-year-old man exposed to trichlorethylene in his work environment for more than 30 years was published in the scientific literature.

In the 21st century, new cases linking the substance with the same pathology are described in a 37-year-old woman who worked cleaning houses and in three workers who used trichlorethylene to clean metals in a factory.

A study of 99 pairs of World War II veteran twins observed a 500% higher risk of Parkinson’s in those people who, due to work or use in certain hobbies, have been exposed to trichlorethylene.

trichlorethylene and cancer

The authors of the new paper, led by neurologist E. Ray Dorsey of the University of Rochester, also note that mice exposed to the substance developed features of the disease. It was found that trichlorethylene (and a derivative, perchlorethylene) has an affinity for lipids, facilitating their distribution in the brain and tissues, causing mitochondrial dysfunction.

These dysfunctions would affect the dopaminergic neurons, the destruction of which causes Parkinson’s, as they are unable to send adequate nerve signals to the muscles and cause the characteristic tremors of this disease. In fact, exposure to the chemical caused selective loss of these neurons in mice, and mitochondrial function deteriorated in specific areas of the brain.

[Descubren qué grupo de neuronas se ve más afectado en los pacientes con párkinson]

Despite this, the European Chemicals Agency (ECHA) and the North American Agency for Toxic Substances and Disease Registry (ATSDR) have not included Parkinson’s among the many risks of trichlorethylene.

If this substance is restricted in Europe and the United States, it is because of its relationship with cancer (mainly kidney, but also liver and lymphomas), in addition to the risk to the fetus from exposure to pregnant women.

The problem is that the characteristics of the product and its ubiquity over several decades make the product more present in our lives than it seems. A 1994 Italian study found relatively high concentrations of trichlorethylene in the blood and urine of three-quarters of the country’s population.. Its presence in groundwater has been recorded in about twenty countries on several continents and its evaporation at room temperature contaminates the outside and inside air, penetrating into schools, homes and workplaces, warn the authors.