Skin Barrier in Normal and Allergic Horses: What Do We Know?

Area of Science:

• Veterinary Dermatology
• Equine Skin Biology
• Immunodermatology

Background:

• Limited information exists on equine skin barrier function.
• Allergic horses exhibit disorganized intercellular lipids in the stratum corneum, akin to canine and human atopic skin.
• Previous studies suggest factors like location, gender, breed, and environment influence normal horse skin barrier parameters.

Purpose of the Study:

• To investigate and compare skin barrier function parameters between normal and allergic horses.
• To explore the functional implications of observed ultrastructural changes in equine allergic skin.
• To contribute to understanding equine skin health and disease.

Main Methods:

• Epidermal ultrastructural analysis of normal and allergic horse skin samples.
• Review of existing literature on equine skin barrier parameters, microbiome, and transcriptomics.
• Analysis of transcriptomic data comparing lesional allergic skin with healthy skin.

Main Results:

• Disorganized amorphous intercellular lipids were found in the stratum corneum of allergic horses.
• Transcriptomic analysis revealed significant differences, including downregulated tight junction and keratin genes, and upregulated serine proteases and IL-13 in lesional allergic skin.
• Upregulation of IL-31 gene expression was observed in keratinocytes from horses with insect bite hypersensitivity.

Conclusions:

• Preliminary findings suggest distinct skin barrier differences between normal and allergic horses.
• The observed ultrastructural and transcriptomic changes in allergic equine skin warrant further investigation.
• Understanding these differences is crucial for developing targeted therapies for equine allergic skin conditions.