Pest Control

Fire ants could offer a new treatment for psoriasis

By Quinn Eastman

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Compounds derived from fire ant venom can reduce skin thickening and inflammation in a mouse model of psoriasis, Emory and Case Western Reserve scientists have shown. The results were published in Scientific Reports.

The findings could lead to new treatments for psoriasis, a common autoimmune skin disease. Topical steroids are now most frequently used for mild to moderate psoriasis, but they have side eff ects such as skin thinning and easy bruising.

Solenopsins are the main toxic components of fire ant venom. They chemically resemble ceramides, which are lipid-like molecules essential for maintaining the barrier function of the skin. Ceramides can be found in many skin care products.

Ceramides can act as a double-edged sword, says lead author Jack Arbiser, professor of dermatology at the School of Medicine. Under certain conditions they can be converted by cells into S1P (sphingosine-1-phos-phate), an inflammatory molecule.

Arbiser and his colleagues devised two solenopsin analogs that look like ceramides, but can’t be degraded into S1P. They then tested them in a mouse model of psoriasis, applying the compounds in a 1 percent skin cream for twenty-eight days. The mice treated with solenopsin analogs displayed decreases in skin thickness compared with controls (about 30 percent). The treated mice also had fewer (around 50 percent less) immune cells infiltrating the skin.

When applied to immune cells in culture, the compounds decreased the cells’ production of the inflammatory signal IL-22 and increased production of anti-inflammatory IL-12.

“We believe that solenopsin analogs are contributing to full restoration of the barrier function in the skin,” Arbiser says. “Emollients can soothe the skin in psoriasis, but they are not sufficient for restoration of the barrier.”—Quinn Eastman

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