The genetic defect weakens the skin barrier and increases the absorption of common household chemicals.
The human body defends itself against harmful chemicals with complex biological shields, with the skin serving as the first line of external defense. However, many people may not know that its strength is a genetic trait, as indicated by a team from the Karolinska Institute and Lund University in Sweden. A new study found that individuals who inherit a specific genetic mutation absorb three common household chemicals more quickly through their skin compared to others. According to the Centers for Disease Control and Prevention (CDC), most people encounter dozens of chemicals daily from cleaning and personal care products at home. Scientists indicate that through skin exposure to these products, some of their chemical components can transfer from the outer surface of the skin to the inside through a process called dermal absorption. Once absorbed, these chemicals can enter the bloodstream and potentially lead to systemic toxicity if the dose and duration of exposure are high enough.
**The Skin as a Primary Defense**
- **The Importance of the Stratum Corneum:**
Chemical absorption largely depends on the properties of the outermost layer of skin, known as the stratum corneum. However, if the stratum corneum is damaged, dry, or compromised in any way, chemicals can enter the body more rapidly. The filaggrin gene, which contributes to the formation of the stratum corneum, is crucial for maintaining the integrity of its barrier and is key to preserving the body's shield. Previous studies have shown that individuals with variations in the filaggrin gene are more prone to certain skin diseases, indicating that they possess a different number of DNA bases than average. Additionally, individuals with filaggrin variation exhibit increased absorption of certain chemicals. The research team sought to clarify whether skin absorption of chemicals increases in people with mutations in the filaggrin gene.
During the study, the team focused on how filaggrin mutations affect skin absorption of three common chemicals: pyrimethanil (a pesticide), oxybenzone (a UV filter found in sunscreen), and pyrene (a hydrocarbon present in wood smoke). The researchers examined over 400 individuals in Sweden to gather genetic information, finding that about 6.5% of these individuals had the filaggrin mutation. The researchers noted that this sample represents the majority of the population in Northern Europe. Subsequently, the researchers brought individuals with filaggrin mutations into the lab for skin testing. For the test, the researchers applied a harmless dose of the three chemicals to their skin for four hours.
Afterward, the researchers analyzed each participant's urine to determine the amount of chemicals metabolized and excreted after passing through the skin. They discovered that pyrimethanil and pyrene moved through the skin more rapidly in individuals with filaggrin mutations; however, more pyrimethanil and oxybenzone were also absorbed, indicating that individuals with compromised skin barriers absorb pesticides faster than anything else. Dr. Karin Probergh, the study's lead author, stated, "For instance, we found that the dermally absorbed dose of the pesticide was doubled in individuals with the filaggrin mutation compared to others. In fact, the skin absorbs a larger amount of certain chemicals as a result of genetic variation."
