Laminitis in Horses: New Clinical Strategies Are Emerging

What if we needed to rethink our approach to laminitis in equines? That’s what the University of Liverpool is proposing. Laminitis remains one of the most debilitating and painful conditions in equines, often leading to euthanasia. Until recently, research focused on laminitis caused by inflammation. But it is now considered a clinical syndrome associated with a systemic disease. Studies on spontaneous endocrine laminitis and models of hyperinsulinemia have changed the understanding of this condition, warranting a reassessment of clinical management and a reorientation of research efforts. We now know that insulin is responsible for laminitis resulting from an endocrine disorder. It plays a role in regulating glucose derived from food. This discovery paves the way for new therapeutic approaches to laminitis. Research conducted notably by veterinarian Cathy McGowan has led to the development of three key areas for improving our understanding of this condition:

• laminitis is now considered a clinical sign of a systemic condition such as an endocrine disorder (particularly Cushing’s disease and equine metabolic syndrome), sepsis, systemic inflammatory response syndrome (SIRS), or obesity;
• laminitis associated with an endocrine disorder is recognized as the predominant form in horses and ponies that primarily exhibit lameness;
• in histology, endocrine-related laminitis is associated with stretching of the lamellar cells rather than damage to the basement membrane. A variable subclinical phase has been identified in some horses, as evidenced by the development of rings on the hoof wall, associated with other changes such as a widened white line and a convex sole. It remains to be determined how hyperinsulinemia leads to the stretching of lamellar epithelial cells, a key early lesion in the pathophysiology of the disease.

  Thus, the key to making progress in the clinical management of laminitis lies in an earlier and more accurate diagnosis of the associated systemic disease, which is crucial not only for managing the condition but also for the prognosis and prevention of recurrences. Furthermore, managing the endocrine disorder at the preclinical stage (circled foot) could help slow, prevent, or even reverse the process of lamellar stretching, which represents a promising therapeutic target in cases of hyperinsulinemia. At present, research efforts are primarily focused on the link between hyperinsulinemia and early histological changes, the involvement of basal membrane lesions, the actions of insulin, and the role of inflammatory mediators.