The PAR2 Antagonist Larazotide Can Mitigate Acute Histamine-Stimulated Epithelial Barrier Disruption in Keratinocytes: A Potential Adjunct Treatment for Atopic Dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin condition with evidence of defects in the barrier properties of the epidermis. Changes in the permeability properties of the tight junction have been reported in AD, and reversing this leaky tight junction may be a potential treatment for AD. This study aimed to determine the effect of larazotide, an antagonist of the protease-activated receptor 2, on the permeability and barrier properties of the tight junctions in keratinocyte monolayers. Normal human epithelial keratinocytes were grown in culture on permeable supports. The effects of larazotide on transepithelial resistance and permeability properties of keratinocyte monolayers were studied before and after histamine challenge. Larazotide mitigated the disruptive effect of histamine on epithelial permeability by increasing the electrical resistance and decreasing epithelial permeability. Larazotide may be beneficial as a topical therapeutic for AD; however, the permeability properties of the short-peptide larazotide through the uppers layers of the epidermis is currently unknown. In conclusion, the protease-activated receptor 2 antagonist larazotide has a protective effect on keratinocyte monolayers and may be useful as an adjunct therapeutic agent to enhance barrier function and promote epidermal healing in AD.