Histological evaluation of human tendinopathy. Representative diseased tendons were stained with Alcian blue to visualize the proteoglycans in patient 12 (A), patient 10 (B), patient 15 (C), patient 24 (D), patient 25 (E), and patient 32 (F). Only a few bundles from patient 12 appear normal. The remaining sections show highly disorganized tissues with increased cell proliferation, increased vasculature, and/or increased GAG content. Scale bar is 200 μM.