Fig. 1

Collagen deposition in the gastrocnemius of CTRL and PAD patients with claudication and tissue loss. a Representative greyscale images of gastrocnemius specimens stained with Masson Trichrome were captured by multi-spectral, bright-field microscopy (20× objective). Specimens were collected from control subjects (CTRL) and PAD patients at Fontaine Stage II (claudication, PAD-II) and Stage IV (tissue loss, PAD-IV) disease. Myofibers delineated by collagen staining, appear black. Collagen density and area are represented by the intensity and extent of the bright pixels, respectively. Arrows point to collagen deposition associated with microvessels. b Collagen density and c collagen area in specimens of CTRL (n = 20), PAD-II (n = 25), and PAD-IV (n = 20) gastrocnemius were analyzed by quantitative multi-spectral microscopy. Collagen density was calculated as area-weighted mean intensity of all collagen events per specimen. Data are presented as mean ± standard error of the mean. Significance denoted as *p < 0.05; **p < 0.01; ***p < 0.001