Chronic equine laminitis is characterised by loss of GLUT1, GLUT4 and ENaC positive laminar keratinocytes.

The research identifies the loss of specific proteins in horse foot cells as a key characteristic in a debilitating connective tissue disorder called chronic equine laminitis. It also suggests potential markers for the disease which could facilitate future research and treatment.

Research Objective

• The team aimed to establish whether the epithelial sodium channel (ENaC), along with the glucose transporters GLUT1 and GLUT4, could serve as markers for identifying equine laminar keratinocytes, the main type of cells in the horse’s foot. They also sought to observe any changes within these cell populations in cases of laminitis, a painful and potentially crippling disease affecting horses’ feet.

Methods

• The researchers used immunohistochemistry, a lab technique that uses antibodies to identify proteins in their natural context within a tissue, coupled with histology, the study of microscopic tissues. They compared the distribution of these proteins in healthy and laminitic equine laminates, parts of the foot, using antibodies specifically engineered to identify ENaC, GLUT1, and GLUT4.

Results

• From their investigation, all three proteins were found in healthy laminar keratinocytes. However, laminitis samples showed chaotic laminar arrays replaced by fibrous scar tissue, indicating tissue damage. Moreover, it confirmed the loss of ENaC, GLUT1, and GLUT4 positive keratinocytes in these samples. The disease did not affect the expression of these proteins in other connective tissue cells.

Conclusion

• This is the first time the expressions of ENaC and GLUT1/GLUT4 proteins have been identified in equine laminar keratinocytes. Not only does this finding further our understanding of the condition, but it also suggests that these proteins can serve as markers for identifying the disease. This finding has wide-ranging implications on developing treatments for the condition.
• However, the authors note that further studies under different conditions, such as bacterial endotoxins, vasoactive amines, lactic acid, and prostaglandins, would be necessary to determine the effects of these conditions on expression and activity of these plasma membrane keratinocyte markers.