Calprotectin in myeloid and epithelial cells of laminae from horses with black walnut extract-induced laminitis.
BACKGROUND
Laminar inflammation is one of the earliest events in equine laminitis. Calprotectin (CP), a Damage-Associated Molecular Pattern protein, is overexpressed in inflammatory conditions of human skin.


OBJECTIVE
CP is overexpressed in the laminar epidermis of horses with black walnut extract (BWE)-induced laminitis.


METHODS
Twenty adult horses.


METHODS
Experimental study. Horses were allocated to one of 4 groups. BWE was administered to horses in 3 groups, which were sampled 1.5, 3, and 12 hours (LAM) later. CP was visualized by immunohistochemistry. Laminar leukocyte counts and intensity of laminar epithelial staining were scored for all animals and statistically analyzed.


RESULTS
Laminar epidermal CP signal was significantly increased (P= .02) at the LAM time point, compared with other groups. Rare leukocytes were detected in laminae with CP staining in CON group, but there were marked increases in number of leukocytes in BWE-treated groups (P= .003). Sequential hematoxylin and eosin staining demonstrated that the majority of CP-positive leukocytes were perivascular polymorphonuclear neutrophils (PMN) at each of the developmental time points. CP-positive PMN and mononuclear cells were detected in perivascular locations and close to the epidermal basement membrane in the LAM group.


CONCLUSIONS
CP expression in the laminar epidermis occurs after extravasation of leukocytes, indicating that leukocyte emigration might be an initiating factor in laminar epithelial stress and inflammation in BWE-induced laminitis. These results indicate a possible role of CP in laminitis pathophysiology and laminar failure.
Faleiros
R R
RR
Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, OH, USA.
Nuovo
G J
GJ
Belknap
J K
JK
D000818:Animals; D004847:Epithelial Cells / Q000378:metabolism*; D005534:Foot Diseases / Q000139:chemically induced / Q000662:veterinary*; D006734:Horse Diseases / Q000139:chemically induced* / Q000473:pathology; D006736:Horses; D031324:Juglans / Q000737:chemistry; D039841:Leukocyte L1 Antigen Complex / Q000378:metabolism*; D022423:Myeloid Cells / Q000378:metabolism*; D010936:Plant Extracts / Q000633:toxicity; D021381:Protein Transport
D039841:Leukocyte L1 Antigen Complex; D010936:Plant Extracts