Suspensory ligament degeneration associated with pituitary pars intermedia dysfunction in horses.

This study investigates the relationship between pituitary pars intermedia dysfunction (PPID) and suspensory ligament (SL) degeneration in horses. The researchers found that older horses with PPID demonstrated signs of SL degeneration, similar to symptoms observed in Peruvian Paso horses and human conditions such as Cushing’s disease or long term corticosteroid therapy.

Objective of the Study

• This study sought to examine the histopathological changes in the suspensory ligament (SL) of horses with pituitary pars intermedia dysfunction (PPID), a common endocrine disorder in older horses.

Study Design and Participants

• The researchers compared the SLs of four older horses presenting clinical signs of PPID, four older control horses, and three young control horses.
• The age range for the horses with PPID was between 17 to 26 years, while the old control group was between 18 to 31 years and the young control group between 4 to 9 years.

Findings and Observations

• In the horses diagnosed with PPID, there were notable changes in the SL, including reduced longitudinal arrangement of collagen fibres, inclusions of cartilage, extracellular matrix and haemorrhage, as well as significant proteoglycan accumulations between SL fibres.
• These alterations align with the degeneration of connective tissues observed in Peruvian Paso horses with SL degeneration, and in humans with Cushing’s disease or after undergoing long-term high dose corticosteroid treatments.

Implications and Conclusion

• The findings from this study highlight a potential association between the degeneration of the suspendory ligament and pituitary pars intermedia dysfunction in horses.
• Further understanding of this relationship may pave the way for new approaches in managing these conditions in horses, potentially improving their wellbeing and lifespan.