Histopathology of insulin-induced laminitis in ponies

Asplin, K. E., Patterson-Kane, J. C., Sillence, M. N., Pollitt, C. C. and McGowan, C. M. (2010) Histopathology of insulin-induced laminitis in ponies. Equine Veterinary Journal, 42 8: 700-706. doi:10.1111/j.2042-3306.2010.00111.x

Author Asplin, K. E.
Patterson-Kane, J. C.
Sillence, M. N.
Pollitt, C. C.
McGowan, C. M.
Title Histopathology of insulin-induced laminitis in ponies
Journal name Equine Veterinary Journal   Check publisher's open access policy
ISSN 0425-1644
Publication date 2010-11
Sub-type Article (original research)
DOI 10.1111/j.2042-3306.2010.00111.x
Volume 42
Issue 8
Start page 700
End page 706
Total pages 7
Place of publication Hoboken, NJ, United States
Publisher John Wiley & Sons
Collection year 2011
Language eng
Formatted abstract
Reasons for performing study: Ponies with laminitis associated with insulin resistance and hyperinsulinaemia lack systemic and/or intestinal inflammatory signs, suggesting a different pathogenesis potentially reflected in differing histopathology.

Objectives: To describe the histological appearance and quantify morphological changes in primary and secondary epidermal lamellae (PEL and SEL) of laminitis lesions from ponies with insulin-induced laminitis.

Equine hoof lamellar tissue was obtained from 4 control ponies and 5 ponies with laminitis induced following infusion of insulin (1036 ± 55 µU/ml) while maintaining euglycaemia for 55.4 ± 5.5 h. Sections from all 4 hooves were stained and examined by a veterinary pathologist. Measurements of lamellar length (PEL and SEL) were made in mid-dorsal sections of the right forefeet by 2 blinded observers. Immunolabelling for calprotectin was performed using a monoclonal antibody.

Results: No lesions were detected in normal ponies. Lesions detected in ponies with laminitis were variable in severity between ponies. Within ponies, SEL lesions were more severe along the axial region of PEL. Lesions included swelling, disorganisation and abnormal keratinisation of epidermal cells, increased mitotic activity and apoptosis. Separation of basement membranes was minimal. Immunostaining revealed inflammatory cells within the lamellar dermis. SEL were significantly elongated in laminitic hooves relative to controls, with the greatest elongation in those attached to abaxial and middle regions of PEL.

Laminitis induced by prolonged infusion of insulin lacked widespread basement membrane disintegration, and increases in epidermal cellular proliferation at axial aspects were marked for this acute stage of disease.

Potential relevance: Defining equine laminitis entirely in terms of separation of the basement membrane may not be appropriate for laminitis associated with hyperinsulinaemia.
© 2010 EVJ Ltd
Keyword Horse
Endocrinopathic laminitis
Epidermal lamellae
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Veterinary Science Publications
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Citation counts: TR Web of Science Citation Count  Cited 17 times in Thomson Reuters Web of Science Article | Citations
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Created: Sun, 31 Oct 2010, 00:12:15 EST