Mesenteric arterionecrosis in natural and experimental equine endotoxaemia.

The study tests whether mesenteric arterionecrosis (a condition characterized by the death of tissues in mesenteric arteries) occurs naturally, as well as when artificially induced, in horses experiencing endotoxaemia, primarily by observing the digestive organs in thoroughbred racehorses suffering from colic or artificially induced endotoxaemia. The presence of similar morphological characteristics of mesenteric arterionecrosis in both groups suggests that the condition may be a specific symptom of equine endotoxaemia.

Methodology and sample selection

• The article explains that the tissues of the mesentery and gastrointestinal tract of 21 Thoroughbred racehorses were examined for the research.
• These included 15 horses that had spontaneous colic, suspecting it as a symptom of endotoxaemia, and 6 horses that were experimentally induced with endotoxaemia. Comparing these two groups aided in the evaluation of mesenteric arterionecrosis under both naturally occurring and artificially introduced endotoxic conditions.

Findings

• The researchers found that mesenteric arterionecrosis was present in 13 out of the 15 horses experiencing spontaneous colic, and in all of the horses with experimentally induced endotoxaemia.
• The common morphological characteristics of mesenteric arterionecrosis in both groups suggested that the development of the condition follows a similar process, whether endotoxaemia occurs naturally or is experimentally induced.

Pathological characteristics observed

• The study found several types of cell changes and damage, including histolysis of the arterial walls, infiltration of blood components into the arterial walls, and changes to the medial smooth muscle cells.
• These muscle cell changes included the formation of many intracellular vacuoles, cytoplasmolysis (the dissolution of the cytoplasm), necrosis (cell death) with the presence of granules and vacuoles, and coagulation necrosis (a form of cell death where the affected tissue solidifies).
• Notably, these changes were similar to those observed in prolonged angiospasm or vasoconstriction conditions, suggesting a link between sustained arterial contraction and the occurrence of mesenteric arterionecrosis.

Conclusion

• Overall, the study posits that sustained arterial contraction, causing damage to the intimal and medial layers of the artery, likely plays a significant role in the development of mesenteric arterionecrosis in cases of equine endotoxaemia.
• The researchers concluded that this condition could be a definitive feature of equine endotoxaemia, given its presence in both naturally occurring and experimentally induced cases.