Gene expression in the lamellar dermis-epidermis during the developmental phase of carbohydrate overload-induced laminitis in the horse.

This research examines the gene expression in the skin layers, or lamellar dermis and epidermis, of horses during the early development phase of carbohydrate overload-induced laminitis. By comparing healthy horses to those in this phase, the study unraveled significant upregulation of 155 genes predominantly involved in pro-inflammatory biochemical or cellular processes.

Study Overview

• The study aimed to better understand the local biochemical and cellular events contributing to the onset of laminitis in horses.
• To do this, gene expression in the lamellar dermis and epidermis of horses was compared between healthy horses and horses in the developmental phase of carbohydrate overload-induced laminitis.

Methodology

• Six healthy adult horses, with no history of laminitis, were selected. These horses were randomly divided into two groups: control and laminitis.
• The control group (n=3) did not receive any treatment and were euthanized at the same time as the laminitis group.
• The laminitis group (n=3) were given oligofructose and euthanized 24-30 hours later, before any clinical signs of laminitis were apparent.
• Sections of lamellar dermis and epidermis were harvested from the dorsal hoof wall of each horse immediately after death for analysis using a bovine microarray chip, which comprises approximately 15,000 genes.

Results

• A significant up-regulation, no down-regulation, of 155 genes was observed in the laminitis group.
• Genes majorly coded for the production of pro-inflammatory biochemical or cellular processes and those involved in protein degradation/turnover.
• Several regulatory or anti-inflammatory genes were also observed to be up-regulated.

Conclusions

• The study observed that the generation of inflammatory mediators within the lamellar tissues occurred before the development of substantial dermal-epidermal separation, inflammatory infiltrate, or vascular changes, and prior to the manifestation of signs of foot pain in the horses.
• While further studies are needed, the research suggests that early and targeted anti-inflammatory therapy may be effective in halting or preventing the development of laminitis in at-risk individuals.