Figure 4.

Abnormal desmin accumu-lation in the myofibers of Peripheral Artery Disease (PAD) gastrocnemius (A) and associated changes in myofiber morphology and extracellular matrix (B). Sections from the gastrocnemius of a PAD subject with moderate to severe myopathy were captured under fluorescence (A) and bright-field (B) conditions with a 10× objective. The specimen (A) was labeled with desmin antibody (green), wheat germ agglutinin (membranes and connective tissue; red) and DAPI nuclear stain (blue). The neighboring section (B) was stained with Masson’s Trichrome (sarcoplasm, red; connective tissue, blue; nuclei, black). The PAD myofibers display dense, irregular accumulations of desmin in the sarcoplasm (A). The myofibers are irregular in shape and size and include many large, rounded and swollen fibers and many small, irregularly shaped fibers (A and B). Several of the large myofibers show evidence of target lesions (filled arrows), vacuoles (arrow heads) and internal nuclei (line arrows) (B), findings consistent with myofiber degeneration. There is obvious expan-sion of the extracellular matrix. Scale, 100 µm.