Platelet activation in ponies with airway inflammation.

The research focuses on platelet activation in ponies with Recurrent Airway Obstruction (RAO), a disease that resembles human asthma. By measuring platelet adhesion ex vivo, the researchers provided evidence that platelets might play a role in the pathophysiology of RAO. They developed in vitro platelet adhesion assays and observed significant increases in platelet adhesion 24 hours after a natural antigen challenge in ponies with RAO.

Research Objectives and Methods

• The primary objective of this study was to understand whether the function of platelets is altered in ponies suffering from active RAO. This alteration was detected ex vivo by measuring platelet adhesion.
• The study involved an in vitro platelet adhesion assay that measures acid phosphatase (AcP) activity colorimetrically. This assay was specifically adapted for use with equine platelets to establish their responses to selected agonists.
• Platelet adhesion and aggregation were evaluated in vitro on platelets extracted from 6 ponies with RAO before, during, and after a 7-hour natural antigen challenge. Another group of three ponies with no history of airway disease was studied as a control group.

Key Findings

• The study found adhesion of equine platelets to serum-coated plastic at concentrations of 10-100 radicaló 10(9)/l.
• The adhesion increased in response to stimulation with platelet-activating factor and thrombin, but not equine interleukin 8.
• Before the antigen challenge, the adhesion of non-stimulated platelets was low. However, it significantly increased (P<0.05) 24 hours after the initiation of the challenge in ponies with RAO, while no significant changes were observed in the control group of ponies.
• No changes in platelet aggregation were observed in either group.

Conclusion

• The in vitro platelet adhesion assay offers an alternative method to evaluate platelet functionality in healthy and diseased horses and is capable of detecting changes not observed with the conventional aggregation assay.
• Circulating platelets were found to activate 24 hours after antigen exposure in ponies with RAO, indicating a potential role in pulmonary inflammation and the pathophysiology of RAO.
• This study suggests that investigating platelet function in RAO and airway inflammation can uncover new aspects of the pathogenesis of inflammatory lung disease in equines.