The ultrastructure of Strongylus vulgaris-mediated equine chronic mesenteric arteritis.

The research focuses on investigating the microscopic structural details of chronic mesenteric arteritis in horses, linked to the Strongylus vulgaris parasite. It identifies the role of smooth muscle cells in producing the extracellular matrix within the affected arteries. It also reveals the presence of abundant fibroblasts in the adventitia, thought to be the source of adventitial collagen.

Investigation of Equine Chronic Mesenteric Arteritis

• The research primarily involves a meticulous ultrastructural examination of arteritis, a condition characterized by inflammation of the artery walls, in horses. Chronic mesenteric arteritis, specifically, corresponds to enduring inflammation occurring in the primary arteries of the mesentery, which is a membrane attaching the intestine to the abdominal wall.
• The cause of arteritis in this context was linked to the Strongylus vulgaris, a common parasitic worm found in horses. The actions of these parasites lead to damage in the arterial walls, triggering the inflammation process and resultant arteritis.

Role of Smooth Muscle Cells and Fibroblasts

• Within the cranial mesenteric artery of a mature mare with chronic arteritis, researchers located cells in the intima (inner layer) and media (middle layer) identified as smooth muscle cells.
• These cells were found in combination with collagen and elastin fibres, forming the extracellular matrix. The extracellular matrix is a complex structural entity surrounding cells and plays a crucial role in tissue and organ functioning. In this case, the presence of collagen and elastin fibres contribute to the strength and elasticity of the arterial walls.
• No fibroblasts, which are a type of cell responsible for synthesising the extracellular matrix and collagen, were found in the intima and media. As a result, the smooth muscle cells were presumed to be the primary source for the extracellular matrix in these regions.
• However, in the adventitia (outer layer) of the same artery, a considerable number of fibroblasts was detected. These cells are likely to be the primary catalyst for the production of collagen in the adventitia, thereby playing a key role in maintaining the structural integrity and overall health of the affected artery.