Assessment of tissue-specific cortisol activity with regard to degeneration of the suspensory ligaments in horses with pituitary pars intermedia dysfunction.
Abstract: OBJECTIVE To identify signs of tissue-specific cortisol activity in samples of suspensory ligament (SL) and neck skin tissue from horses with and without pituitary pars intermedia dysfunction (PPID). SAMPLE Suspensory ligament and neck skin tissue samples obtained from 26 euthanized horses with and without PPID. PROCEDURES Tissue samples were collected from 12 horses with and 14 horses without PPID (controls). Two control horses had received treatment with dexamethasone; data from those horses were not used in statistical analyses. The other 12 control horses were classified as old horses (≥ 14 years old) and young horses (≤ 9 years old). Standard histologic staining, staining for proteoglycan accumulation, and immunostaining of SL and neck skin tissue sections for glucocorticoid receptors, insulin, 11β hydroxysteroid dehydrogenase type 1, and 11β hydroxysteroid dehydrogenase type 2 were performed. Findings for horses with PPID were compared with findings for young and old horses without PPID. RESULTS Compared with findings for old and young control horses, there were significantly more cells stained for glucocorticoid receptors in SL samples and for 11 β hydroxysteroid dehydrogenase type 1 in SL and skin tissue samples from horses with PPID. Insulin could not be detected in any of the SL or skin tissue samples. Horses with PPID had evidence of SL degeneration with significantly increased proteoglycan accumulation. Neck skin tissue was found to be significantly thinner in PPID-affected horses than in young control horses. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that tissue-specific dysregulation of cortisol metabolism may contribute to the SL degeneration associated with PPID in horses.
Publication Date: 2018-01-24 PubMed ID: 29359976DOI: 10.2460/ajvr.79.2.199Google Scholar: Lookup
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- Journal Article
Summary
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The research aims to determine the role of tissue-specific cortisol activity in suspensory ligament degradation in horses with pituitary pars intermedia dysfunction (PPID). It highlights differences in cortisol activity, proteoglycan accumulation, and tissue thickness between horses with and without PPID.
Sampling and Procedure
- Tissue samples were taken from suspensory ligament (SL) and neck skin of 26 horses both with and without PPID, post-euthanasia. Twelve of the horses had PPID, while 14, divided into older (14 years and older) and younger (9 years and younger) groups, did not.
- Two of these control group horses had been treated with dexamethasone and were not included in the statistical analyses.
- The standard staining procedure, along with staining for proteoglycan accumulation, was implemented. Immunostaining of SL and neck skin tissue sections was performed for glucocorticoid receptors, insulin, and the enzymes 11β hydroxysteroid dehydrogenase type 1 and 2.
- Findings in PPID-affected horses were compared with younger and older horses in the control group.
Results
- Compared to the control groups, horses with PPID had significantly more cells stained for glucocorticoid receptors in the SL samples. The enzyme 11β hydroxysteroid dehydrogenase type 1 had more of its presence in both SL and skin tissue samples.
- Insulin presence could not be detected in any of the tissue samples from both groups.
- There was a significant increase in proteoglycan accumulation in the SL of horses with PPID, indicating degeneration. Similarly, the neck skin tissue in PPID-affected horses was significantly thinner than that of the younger control group.
Conclusion and Clinical Relevance
- The study results suggest that tissue-targeted dysregulation of cortisol metabolism may be a pivotal factor contributing to the degeneration of the suspensory ligament associated with PPID in horses.
Cite This Article
APA
Hofberger SC, Gauff F, Thaller D, Morgan R, Keen JA, Licka TF.
(2018).
Assessment of tissue-specific cortisol activity with regard to degeneration of the suspensory ligaments in horses with pituitary pars intermedia dysfunction.
Am J Vet Res, 79(2), 199-210.
https://doi.org/10.2460/ajvr.79.2.199 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Dexamethasone
- Female
- Horse Diseases / metabolism
- Horse Diseases / pathology
- Horses
- Hydrocortisone / metabolism
- Ligaments / metabolism
- Ligaments / pathology
- Male
- Pituitary Diseases / metabolism
- Pituitary Diseases / pathology
- Pituitary Diseases / veterinary
- Pituitary Gland, Intermediate / metabolism
- Pituitary Gland, Intermediate / physiopathology
Citations
This article has been cited 4 times.- Kirkwood NC, Hughes KJ, Stewart AJ. Pituitary Pars Intermedia Dysfunction (PPID) in Horses. Vet Sci 2022 Oct 10;9(10).
- Shimada M, Wada K, Tanaka S, Murakami S, Kanno N, Hayashi K, Hara Y. Effects of long-term and high-dose administration of glucocorticoids on the cranial cruciate ligament in healthy beagle dogs. PLoS One 2022;17(1):e0262206.
- Haythorn A, Young M, Stanton J, Zhang J, Mueller POE, Halper J. Differential gene expression in skin RNA of horses affected with degenerative suspensory ligament desmitis. J Orthop Surg Res 2020 Oct 7;15(1):460.
- Guest DJ, Birch HL, Thorpe CT. A review of the equine suspensory ligament: Injury prone yet understudied. Equine Vet J 2025 Sep;57(5):1167-1182.
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