Figure 5. Immunohistochemical analysis of markers of smooth muscle cell differentiation and de-differentiation.

(A) α-actin expressing smooth muscle cells localize to the side of the abdominal aorta involved in aneurysmal remodeling (100× magnification). (B) As compared to the non-involved aorta, α-actin expression is more diffuse (arrow) in the SMCs involved in aneurysmal remodeling (200× magnification). (C) α-actin expression is localized to SMCs within the medial layer and to SMCs outside of the external elastic lamina (400× magnification). (D) Hyaluronic acid expression is localized throughout the AAA and in cells within the medial side of the external elastic lamina. The boxed area is shown within the insert at 400× magnification. Brown staining from DAB indicates α-actin or hyaluronic acid detection and sections are counterstained with hematoxylin (blue).