Endocrine (hormone) related cases of laminitis are now thought to be the most common form of laminitis and occur when certain types of horses and ponies graze lush pasture or consume a high starch and/ or sugar diet. Whilst it has been known for some time that a high level of insulin in the blood can cause acute (rapid onset) endocrine laminitis, exactly how this happens remains unclear. However new research conducted by the University of Melbourne’s Faculty of Veterinary Science in conjunction with SPILLERS, has uncovered part of the missing link…
Insulin
Insulin, a hormone produced by the pancreas, regulates blood glucose sugar. The release of insulin signals cells, mainly in muscle and the liver, to absorb glucose from the blood. However many horses and ponies prone to laminitis produce abnormally high levels of insulin in response to eating a high starch and/ or sugar meal, suggesting that it is this peak in blood insulin that may lead to endocrine laminitis.
The missing link
In order for insulin (or other hormones) to produce its effects, it must interact with specific receptors on the surface of cells. However there appears to be very few or no insulin receptors on lamellar cells which in the past, has left scientists confused about how large spikes in insulin might cause laminitis.
New findings
Although lamellar cells do not appear to have insulin receptors on them, they do have receptors for a hormone called insulin-like growth factor 1 (IGF-1). In a recently published study, researchers incubated lamellar cells with increasing concentrations of insulin. Not only did they find that that high concentrations of insulin caused a cross reaction with IGF-1 receptor cells, this effect could be prevented by using an antibody that specifically blocks only IGF-1 receptors.
What next?
This study provides part of the missing link between high levels of insulin in the blood and laminitis. Further research to understand exactly how cell changes in the hoof induced by high insulin may cause laminitis is already underway. However it seems that developing drugs which target IGF-1 receptors could help to prevent and treat laminitis in the future.
For more advice on feeding laminitic horses and ponies on contact the SPILLERS Care-Line
Reference
Baskerville C.L., Chockalingham, S., Harris, P.A., Bailey S.R. (2018). The effect of insulin on equine lamellar basal epithelial cells mediated by the insulin-like growth factor-1 receptor. PeerJ 6:e5945 (DOI 10.7717/peerj.5945).
Many thanks
Thanks a lot for this update on researches about laminitis.
I am very concerned about this issue as my TB mare suffers from grass intake every year at this season. None of the manifold vets exams has revealed any laminitis signs. But she obviously limps from the 4 feet, the left foreleg being the most aching as sometimes she hold it up.
What is surprising is that she shows signs of discomfort after just an hour of grazing even in winter.
Her diet : 3l your CM and 8kg hay. She has a muzzle when in her paddock (but she managed to catch grass at its evil root).
I've forwarded to her vet a topic on the impact of some digestive issues in the hindgut (fructans fermentation and bacteria production) on laminitis
My questions are there any supplement that could help to mitigate this issue.
Is a more workout could help or conversely is to be ovoid ?
Thank you very much for your help.
Souad
Please contact the Care Line on 01908 226626 for more specific advice for your horses
Very interesting.
I have managed this by restricted grazing, low sugar diet, metformin tablets and a helpful & realistic vet. All this works and luckily my horse is well and happy!