A common fatty acid found in the Western diet breaks down into compounds that raise temperature and pain—but not itch—sensitivity in psoriatic lesions, according to a study published in JID innovations.
Researchers at North Carolina State University, collaborating with researchers at the National Institutes of Health, Baltimore, MD, carried out the study.
The research team used mass spectrometry to look at lipids in skin samples from people with psoriasis. They were interested in two fats from a specific kind of fatty acid called linoleic acid. The former can change into the latter after interaction with certain enzymes.
“We noticed high levels of two types of lipids derived from linoleic acid in psoriatic lesions,” says Santosh Mishra, associate professor of neuroscience at North Carolina State University and corresponding research author. “That led us to wonder whether the lipids might affect how sensory neurons in these lesions communicate. We decided to investigate whether their presence could be related to the temperature or pain hypersensitivity that many psoriasis patients report.”
Furthermore, the researchers found that both types of fats bind to receptors on nerve cells in the skin, but the more stable type, 9,10,13-THL, had a longer-lasting effect than 9,13-EHL. According to the researchers, when these fats bind to the nerve cells, they activate specific receptors, called The transient receptor potential vanilloid 1 and ankyrin 1 (TRPV1 and TRPA1, respectively), which are involved in temperature and pain sensitivity, and this sends signals to the brain.
Surprisingly, the researchers discovered that these fats did not affect itch.
“It was surprising that these lipids could create hypersensitivity but not impact itch sensation, which is usually the most troublesome symptom associated with psoriasis,” Mishra says. “This most likely has to do with how the neuron is activated — a mechanism we still haven’t uncovered.”
The researchers believe their discovery may enhance the comprehension of the interaction between lipids and sensory neurons and potentially lead to more effective pain and sensitivity treatments for individuals with psoriasis.
“We know that this lipid moves from one form to another, but don’t yet know what causes that,” Mishra says. “We also know what protein the lipids are binding to, but not where the bond occurs. Answering these questions may hopefully lead to new therapies—or dietary solutions—for some psoriasis sufferers.”
