Decreased glucose metabolism causes separation of hoof lamellae in vitro: a trigger for laminitis?

The research suggests that a decrease in glucose consumption may be a contributing factor in the development of laminitis in horses, a condition in which the hoof separates from the leg, by separating hoof lamellae in a laboratory setting.

Research Methodology and Findings

• The researchers conducted the study using explants (tissue samples) from horses’ hooves, investigating how the hoof explants responded in environments with differing glucose levels.
• The exploratory process involved incubating the hoof explants in two main mediums: Dulbecco’s modified Eagle medium (D-MEM) with 25 mmol/l glucose and saline. The researchers recorded that the explants separated within 36 hours in saline, while they remained intact for up to 8 days in the glucose-rich D-MEM.
• The study showed the hoof explants separation occurred between the basal epidermal cells and basement membrane, mirroring the separation experienced in actual cases of laminitis.
• Upon the addition of glucose to the saline, the hoof explants’ separation was prevented, further highlighting the role of glucose in maintaining the hoof structure integrity.
• However, adding 2-deoxyglucose (a glucose analog inhibiting glycolysis) or aminophenylmercuric acetate to D-MEM induced separation. Furthermore, the addition of these substances resulted in an inhibition of glucose consumption by the hoof explants.
• The researchers noticed high levels of glucose consumption during the first 2 days of incubation, which significantly decreased over the next 6 days. Remarkably, the decrease in glucose consumption did not result in hoof explant separation up to the 8 day end-point of the trial.

Implications of the Findings

• The results from this in-vitro experiment suggest that initial hoof explant integrity is dependent on glucose consumption. These results provide a theoretical explanation for the onset of laminitis under certain conditions that may cause significant metabolic shifts away from glucose consumption in peripheral tissues.
• Such situations could include excessive carbohydrate intake, acute inflammation, corticosteroid therapy, or hyperlipidemia.
• The study proposes that if a rapid metabolic shift occurs, faster than the hoof tissue can adjust to an alternative energy substrate, hoof separation and consequently laminitis may occur.
• This hypothesis potentially provides a novel approach in understanding the pathophysiology of laminitis and could lead to improved therapeutic strategies.