Lamellar Neutrophil Myeloperoxydase Infiltration in Hyperinsulinemic-Induced Laminitis

peer reviewedIntroduction - Laminitis is a pathology of the equine digit resulting in failure of the dermo-epidermal interface. Inflammation is a central player in its pathophysiology. Neutrophil activation and the presence of myeloperoxidase have been observed in the black walnut heartwood extract model. However less is known about their role in the hyperinsulinemia model. Materials and methods - Five horses were included in the study and randomly assigned to a control group (n = 2) and a prolonged euglycemic hyperinsulinemic clamp (pEHC) group (n = 3). Histological sections of lamellar tissue from all horses were immunohistochemically stained for myeloperoxidase as well as counterstained with hematoxylin-eosin. The sections were examined for histopathological evidence of laminitis and myeloperoxidase. Results – Histopathological changes that characterize insulin-induced laminitis and increased presence of myeloperoxidase, especially in the dermal lamellae, were observed in histologic sections of pEHC-treated horses compared to control horses. Conclusion - Neutrophil activation with myeloperoxidase release may play a role in the pathophysiology of endocrinopathic laminitis. Their exact implications warrant further investigation