Decreased expression of p63, a regulator of epidermal stem cells, in the chronic laminitic equine hoof.

The research explores how reduced activity in a regulatory gene of epidermal stem cells, p63, might contribute to the hoof disease known as equine chronic laminitis.

Objective & Methods

• The researchers set out to investigate the relationship between the regulator of epidermal stem cell proliferative potential, known as p63, and a hoof condition in horses called chronic laminitis.
• The team gathered and analyzed epidermal tissues from the skin, coronet, and lamellae of the dorsal foot of both healthy horses and horses suffering from chronic laminitis. The methods used included histopathology, immunofluorescence microscopy, and quantitative immunoblotting.

Results

• Laminitic horses showed a lower count of p63 positive cells in their hoof lamellae, especially in the distal region.
• This lowered expression of p63 in the laminitic distal lamellar region was verified through quantitative immunoblotting.
• The reduction in p63 expression was most pronounced in the abaxial region next to the hoof wall. This was significantly related to the formation of terminally differentiated, dysplastic, and hyperkeratotic epidermis in this area.
• In contrast to that, control horses displayed high p63 expression throughout the axial-abaxial axis.

Conclusions

• The p63 expression in horses was found to be similar to that in humans and rodents, hinting that it can serve as a marker for the proliferative potential of equine epidermal stem cells.
• The chronic laminitic hoof showed significantly lower p63 expression, implying that laminitic hoof epithelium has a lesser tendency to proliferate, with a shift towards differentiation. This could reflect a decrease in the activity of epidermal stem cells in laminitic hoof.
• It was suggested that p63 plays a role in maintaining hoof lamellae, and that its misregulation may lead to epidermal dysplasia during lamellar wedge formation.

Implications of the Study

• The study indicates that a loss of epidermal stem cells may contribute to the development of equine laminitis.
• The researchers propose that transplanting p63-positive epidermal stem cells from unaffected areas could potentially serve as a regenerative treatment for horses afflicted with laminitis.