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This article is an excellent literature review and offers a summary of the two leading theories on the biology of acute laminitis caused by systemic illness. Vascular theory suggests a relationship to altered blood flow. Metabolic theory proposes toxins and enzymes acting at the cellular level are responsible.
Bounding digital pulses and changes in hoof wall temperature suggest periods of both increased and decreased circulation occur during laminitis. There are clear alterations in capillary bed circulation that provide the flow of oxygen, nutrients and waste materials in and out of the laminae. How these occur and the role played by vessels that bypass the capillary beds (arteriovenous shunts) is uncertain. Tissue necrosis, edema, and platelet activity are all thought to be involved.
The work of Dr. Christopher Pollitt and others suggests that certain enzymes and toxins act directly as “laminitis trigger factors” in the developmental phase. This theory suggests toxins released from bacterial flora in the gastrointestinal tract over stimulate or disrupt normal enzymatic processes that are responsible for hoof growth, causing laminitis.
The authors conclude both theories, along with other inflammatory processes, may simultaneously be responsible for acute laminitis and the mechanical failure of the attachment of bone to hoof walls. But they point out that medical treatments directed at each process have failed to prevent the disease.
— Moore RM et al. Equine Vet J. 2004;36:204-209.
This experimental study evaluated the effectiveness of cooling the distal…