Hoofcare and Lameness Magazine | Newsletter November, 1998

H & L Online News
November, 1998

Report from the Laminitis Summit Conference:

World’s Top Researchers Go Far Afield for Data

by Fran Jurga
STONELEIGH, ENGLAND-The lush green fields of rural Warwickshire, England must have looked tainted to attendees of the 1998 International Research Conference on Equine Laminitis, sponsored by Dodson and Horrell, Ltd. in September, 1998.For two days, experts from around the world shared their latest findings on the dreaded disease of laminitis. In retrospect, the conference could have been divided into two topics: grass chemistry and the process of developmental laminitis. In truth, both groups were talking more or less about the same thing, but the minute details of grass chemistry definitely presented new information, while the process information presented a dichotomy of ideas between two leading researchers.Hoof capsule qualitiesThe conference introduced a new group of researchers in the United Kingdom, lead by Major J.D. Reilly, who is conducting research at De Montfort University in England.One of Reilly’s observations included the transformation of the white line following laminitis. Reilly documented that in total collapse of the coffin bone (P3), a second white line may be formed. He writes, "It is also possible that changes occur to the stratum medium of the hoof wall that are yet to be discovered."Out to grassIf there is one word that will be remembered from the British conference, it is "fructans". Researchers from the Institute of Grassland and Environmental Research in Wales detailed how grass stores and releases energy in the form of sugars. An interesting fact is that most plants use starch as their storage carbohydrate, while the grasses of the world’s temperate climates (i.e., neither tropical nor polar) store carbohydrate as fructan. Temperate grasses are high in water soluble carbohydrate (WSC) which would be made up of varying levels of sucrose, fructose, glucose, and fructans. Fructans are chains of fructose molecules linked together.The Welsh researchers gave an example of a frosty morning. Bright sunlight would stimulate fructan production, but low temperatures would slow down growth, making the fructan accumulate.What happens when a horse eats grass that is high in fructan? Researchers are carefully studying this question. Fructans are considered beneficial to the digestive health of pigs and humans, but horses are different. Also, on a sunny day, a horse could be chomping down a diet that is extremely high in fructan. This might lead to changes in the hind gut, such as the proliferation of some species of bacteria and micro-flora, while others might find their populations decimated. Researchers speculate that this might be the cause of grass-induced laminitis.Speculation is that new research about fructan and its role in laminitis will result in new mixtures of grass seed for pastures, especially mixed with species that might be stress-resistent, or biologically-engineered to control fructanlevels. However, much research still needs to be done to find out how muchfructan it takes to trigger laminitis, and how much variation their may between horses of different breeds, sexes, or sizes.Mechanisms of laminar destructionTwo divergent points of view on how the damage to the foot occurs werepresented by Australian researcher Chris Pollitt and American researcher David Hood. Pollitt presented data that the damage is caused by a neuro-chemical laminitis triggering factor (LTF), not by either an increase or decrease in blood flow to the foot.Meanwhile, research from the Hoof Project at Texas A&M indicates that a decrease in blood flow to the foot deprives laminae of oxygen and other nutrients, causing them to separate. Both researchers agree that the question is still very open and that more work needs to be done.Prozac for laminitis?Simon Bailey of the Royal Veterinary College, London presented research on endotoxin’s role in laminitis. While endotoxin alone will not cause laminitis, other mediating factors may disturb the blood supply to the laminae. The RVC research group is studying serotonin, which is made in the cells lining the gut and is released into the blood. Bailey said that it is a potent blood constrictor, particularly in the presence of steroids, which often are involved in some of the worst cases of laminitis.Serotonin in humans is linked to neurotransmitters; supplementation of serotonin though the popular drug "Prozac" has been shown to be effective against depression in humans. Serotonin may have a completely different role in the horse.

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