Researchers from the University of Birmingham (UoB) and the University of Naples Federico II have found that a sequence of three amino acids could significantly reduce the severity of psoriasis with fewer side effects than conventional treatments.
The study published in Pharmacological Research focused on the naturally occurring PEPITEM molecule, which regulates inflammation and consists of a chain of 14 amino acids.
Approximately 125 million people worldwide are affected by some form of psoriasis, a chronic inflammatory condition that typically affects the skin, nails and joints.
Up to 90% of patients have plaque psoriasis, characterised by distinct round or oval plaques covered by silvery-white scales that can be itchy, painful and interfere with sleep.
The condition is typically treated with emollients or creams containing vitamin D analogues, vitamin A or corticosteroids, which can only be used for short periods due to the side effects that occur with continuous use.
Ed Rainger, professor of chronic inflammation in the department of cardiovascular sciences, UoB, said: “While there are a number of therapies for psoriasis, there is a clear need for new therapeutic agents that can be used continuously, and without the risk of excessive side effects, to prevent psoriasis flares.”
The UoB team identified the smallest parts of the PEPITEM molecule that influence immune cells and inflammation in psoriasis.
After finding and optimising two sequences of three amino acids that showed biological activity comparable to the full-length PEPITEM molecule, they chose the most promising sequence. This was then evaluated by researchers from the University of Naples Federico II using an animal model of disease.
When applied topically in an emollient cream every day for seven days, the sequence resulted in a clear reduction in psoriasis severity compared to untreated animals, confirmed using the Psoriasis Area and Severity Index (PASI).
The study also showed that both PEPITEM and the tripeptide sequence reduced the PASI score by 50%, making it comparable to the steroid cream clobetasol propionate 0.05%.
“This study also raises the interesting possibility that PEPITEM derived peptides could be used in combination with other psoriasis therapies, allowing lower dosing for longer durations, for example, a ‘steroid sparing’ approach, to reduce the side effects associated with prolonged use of such agents,” Rainger said.