Insulin dysregulation.

The research article explores the phenomenon of insulin dysregulation, its causes, and implications, primarily focusing on its role as a significant factor in equine metabolic syndrome which leads to laminitis in horses, ponies and donkeys. It touches upon diagnostic measures and discusses possible mitigation strategies for the condition.

Insulin Dysregulation: Definition and Implications

• Insulin dysregulation refers to metabolic irregularities typified by boosted insulin levels, medically termed hyperinsulinaemia, and insulin resistance. They contribute significantly towards equine metabolic syndrome, a cluster of endocrine and metabolic irregularities leading to laminitis in equine animals.
• Laminitis is a painful and potentially crippling disease affecting horses, ponies, and donkeys, causing the tissues connecting the hoof wall to the pedal bone to inflame.
• In addition, insulin dysregulation may also occur in foals due to prematurity or systemic illness.

Causes of Insulin Resistance

• The paper discusses various causes of insulin resistance, including obesity-related pathology, systemic inflammation, and pituitary pars intermedia dysfunction, effectively an endocrine disorder in horses resulting in the abnormal growth of pituitary gland tissue.
• It also outlines physiological responses causing insulin dysregulation, such as stress and pregnancy.

Diagnosis and Measurement of Insulin Dysregulation

• Though most research so far has focused on insulin resistance, growing interest is shown in hyperinsulinaemia itself and how insulin responds to feeding.
• To assess insulin responses to dietary carbohydrates, either an oral sugar test or in-feed oral glucose tolerance test can be administered. These tests are now recommended for use in routine clinical practice.
• Incretin hormones, which are released from the gut after meals and stimulate insulin secretion, are also identified as likely contributors to postprandial hyperinsulinaemia and are currently being researched.
• Insulin resistance can further increase hyperinsulinaemia. Insulin sensitivity, a measure of insulin resistance, can be gauged by a combined glucose-insulin test or intravenous insulin tolerance test, where insulin is externally administered and glucose uptake rate into tissues can be measured.

Management of Hyperinsulinaemia

• Hyperinsulinaemia’s diagnosis and management are advised to decrease laminitis risk.
• The term ‘insulin dysregulation’ is thus an umbrella term, denoting excessive insulin reactions to sugars, fasting hyperinsulinaemia and insulin resistance – all equine metabolic syndrome components.