Wednesday, April 23, 2008

Laminitis-the roll of Hyperinsulinemia

The AAEP journal Equine Veterinary Education frequently publishes highlights of clinically relevant papers and this months edition does just that. There are several very interesting abstracts presented including the following.
"Induction of Laminitis by prolonged hyperinsulinemia in clinically normal ponies" by K.E.Asplin et al.
The purpose of the study was to determine what are the effects of prolonged insulin administration
on hoof wall integrity. High serum insulin states exist in the horse such as in Metabolic Syndrome and the associated insulin resistance. In this study 9 clinically normal ponies were divided into 2 groups, 1. treated n=5 ,2. control n=4. The treated group was given insulin over a 72 hour period via a euglycemic-hyperinsulinemic clamp technique which keeps the blood glucose level normal in the face of increased insulin. there was no gastrointestinal disease and no systemic illness during the study, ruling out those causes of laminitis. In the treatment group all of the ponies developed clinical and histological laminitis (Obel grade 2) in all 4 feet.
This is significant because it indicates the role of insulin in laminitis, independent of hyperglycemia or colonic fermentation. Perhaps we should be looking at serum insulin during times of crisis or stress as our indicator of potential laminitis.

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