The Laminitis Link

Exactly how insulin can lead to laminitis is still unknown, but the link between the two is certain. “Regarding how insulin and laminitis are linked, there are several different potential pathologies,” says Shannon Pratt-Phillips, DVM, of North Carolina State University. “Research has shown that if you infuse insulin into a horse at high levels, this can cause laminitis.”

She adds that glucose itself may also contribute to laminitis. “In other species, particularly humans and rodent models, when the glucose st upward, something called glucose toxicity occurs. Just having too much glucose in the bloodstream can damage membranes. This is when we see humans with type 2 diabetes who develop gangrene. It can be a result of glucose causing damage to the little blood vessels within the feet or within the eye—causing glaucoma.”

Obesity associated with EMS may also play a role. “In an obese horse, fat can actually produce hormones and inflammatory proteins that put the body into an inflammatory state. This may directly affect how that cascade happens within the cells after insulin is present. Then the obesity and inflammation can sensitize the vessels of the foot. If the horse is already in an inflammatory state and those blood vessels are already somewhat damaged by the inflammatory proteins, then when you get a whammy of glucose or insulin or something that is further damaging, this can push the situation over the edge.”