Regulation of equine fibrinolysis in blood and peritoneal fluid based on a study of colic cases and induced endotoxaemia.

The research on equine gastrointestinal diseases highlights that much of the illness is due to the impact of endotoxin on haemostasis. In this study, the main fibrinogen activator and inhibitor, t-PA and PAI-1 respectively, were identified in horse blood. Through experiments, it was noted that the equine fibrinolytic system reacts to endotoxin similarly to humans, with an early rise in t-PA followed by a larger and longer increase in PAI-1 activity. Comparing healthy and diseased horses, the study found that plasma PAI-1 and peritoneal t-PA levels were higher in the diseased horses and correlated with the presence of endotoxin. The study suggests that fibrinolysis regulation is the same in horses and humans and that it is altered in sick horses with gastrointestinal diseases.

Research Objective and Methodology

• Scientists aimed to comprehend how the equine fibrinolytic system responds to endotoxin, as this was previously less understood. They sought to explore this by identifying and studying the key elements, t-PA and PAI-1, present in equine blood.
• Researchers designed experiments that exposed the equine fibrinolytic system to endotoxin. The response of the fibrinolytic system was then observed and compared with the reported response in humans.
• This research also featured an analysis of plasma and peritoneal fluid of healthy horses (n=38) and horses suffering from gastrointestinal diseases (n=150) to study the response ofthis system in clinical endotoxaemia (when there are endotoxins present in the blood).

Findings and Conclusion

• Researchers observed that plasma PAI-1 and peritoneal t-PA were increased simultaneously in horses with gastrointestinal diseases; these increases were associated with endotoxin presence.
• The study established that fibrinolysis in horses operates similarly to that in humans — characterized by an initial t-PA activity rise followed by a sustained PAI-1 activity increase when exposed to endotoxins.
• The research also identified that the regulation of fibrinolysis changes in horses afflicted with gastrointestinal diseases, implying a specific response to endotoxaemia, suggesting a link between endotoxaemia and the progression of gastrointestinal diseases in horses.
• The study concluded that events in the vascular system may not always reflect the events in the peritoneal cavity (part of the abdomen), indicating the complexity of the equine fibrinolytic response and underscoring the significance of localized analyses in understanding the full impact of endotoxins.