A collection of the latest research from around the world focusing on the complex equine disease laminitis has been made available for free to veterinarians and horse owners.
Laminitis is the second biggest killer of domestic horses. As knowledge of the pathophysiology, diagnosis and treatment of the deadly condition continues to grow, the Equine Veterinary Journal (EVJ) has published Understanding and managing equine endocrinopathic laminitis, a special online collection of 27 papers and three accompanying editorials compiled by EVJ Associate Editor Nicola Menzies-Gow and Dr Melody de Laat from the Queensland University of Technology in Australia.
Over the past 10 years researchers have made great strides in understanding the pathophysiology of endocrinopathic laminitis. De Laat summarised the collection’s papers on the links between insulin dysregulation, equine metabolic syndrome (EMS), pituitary pars intermedia dysfunction (PPID) and laminitis.
“We have defined insulin is the key player in endocrinopathic laminitis. We know horses and ponies with EMS and PPID are at an increased risk for developing endocrinopathic laminitis and we have come to understand that it’s insulin dysregulation in these animals which is helping to drive the laminitis,” De Laat said.
She added there was much discussion about the role of obesity in laminitis. A couple of pathophysiology articles in the collection look at the fact that generalised obesity isn’t necessarily a factor of endocrinopathic laminitis.
“What’s actually going on in the foot of an animal with laminitis is still little understood. Several papers focus on lamellar lesions. Others look at the role that growth factor receptors may play in the disease,” she said.
“I am really optimistic that within the next 10 years we are going to be able to understand the pathophysiology of this condition really well. And then we’ll be able to turn our attention to new treatment options for the disease, which will help horses to become pain-free.”
Dr Nicola Menzies-Gow’s editorial reviews the collection’s papers on the diagnosis of endocrinopathic laminitis. An accurate diagnosis of laminitis relies on owner recognition of the disease. One of the papers sought to validate this and identified 45% of cases diagnosed by the vet which were not recognised by owners, highlighting the need for better education of owners.
The insulin link
“Detection of insulin dysregulation is essential to identify animals at increased risk of endocrinopathic laminitis so that the preventative management strategies can be focused on these individual animals,” said Menzies-Gow, who works at the Royal Veterinary College, London.
Several papers focus on variables of oral sugar tests used to detect insulin dysregulation, such as dose of glucose or corn syrup, pre-test starvation and the effects of breed, diet and season. A further study concludes that the optimal test for tissue insulin resistance is the insulin tolerance test, while two other papers relate to assay validation and the most effective tests to use.
While insulin dysregulation is a central feature of endocrinopathic laminitis, another paper evaluates other risk factors before the disease occurs and concludes that high insulin concentrations and low adiponectin were associated with an increased risk of developing the disease in the next one, two and three years.
Nick Bamford, an equine vet with both clinical and research expertise in laminitis, summarises the articles relating to the treatment of endocrinopathic laminitis, either through the immediate applicability of their findings to daily veterinary practice or by highlighting novel approaches that hold promise for future therapeutics.
The importance of dietary modification and exercise in obese horses and ponies is discussed in one article while another looks at the role of farriers as a potential first point of contact for many owners of laminitic animals. “Optimal treatment of laminitis requires collaboration between vets, farriers and owners,” Bamford said.
Unmanageable pain is a common reason for euthanasia in horses with chronic laminitis. Two articles in the collection evaluate other potential analgesic options that may help improve pain control. Two further papers look at the best options for applying digital hypothermia, which is the only therapeutic intervention proven to dramatically reduce the severity of sepsis-related laminitis.
There is hope on the horizon for more sophisticated treatment options, as highlighted in a paper that describes a novel therapy approach to deliver therapeutic proteins deep within the equine foot.
“This special collection is important for every equine veterinary practitioner, whether an ambulatory vet or a clinician,” said Celia Marr, editor of the EVJ.
“It brings together the most current work not only on the pathophysiology of endocrinopathic laminitis but also the more practical elements of diagnosis and treatment. With fascinating work being conducted on novel treatment therapies there is every hope that we are now working towards overcoming the obstacles presented by this complex and persistent disease.”
• Reference collection: Understanding and managing equine endocrinopathic laminitis