Fig. 8
Murine endothelialized engineered skeletal muscle supports the formation of organized vascular networks in traumatically injured muscle. a Representative confocal microscopy images of perfused vasculature from longitudinal tissue sections in the region of regeneration adjacent to the endothelialized randomly oriented or endothelialized aligned transplanted skeletal muscle constructs at 21 days after implantation. Endothelial cells are identified by CD31 (red) expression. Perfused vessels are indicated by co-expression of CD31 (red) and fluorescently labeled isolectin (turquois). Insets are higher magnification images of the center of the engineered tissues as depicted by white boxes. Arrow designates orientation of aligned nanofibrillar scaffold. Scale bar (inset) denotes 100 μm, Scale bar denotes 500 μm. b Anisotropy is used to quantify the directional dependence towards the formation of parallel-aligned vascular networks. A value approaching zero corresponds to unrestricted (non-patterned) paths, whereas a value approaching one denotes restriction to one axis to form a parallel-aligned spatial pattern (n = 4). Inset shows representative frequency plots generated by two-dimensional Fast Fourier Transform analysis, in which random orientation of vascular networks are depicted as pixels evenly distributed about the central origin, whereas parallel alignment of vascular networks is depicted as pixels preferentially organized along a single axes (vertical). Quantification of engineered muscle (Eng Muscle) and endothelialized engineered muscle (Endothelialized Eng Muscle) treatment groups is shown. c Global angle of alignment of vascular networks was quantified as the angle formed by the relative orientation of the vascular networks, relative to the axis of the aligned nanofibrils. A degree of alignment of 0 depicts parallel alignment of vascular networks to the aligned nanofibrils. For randomly oriented scaffolds, an arbitrary axis is used (n = 4). For indicated comparisons: p ≤ 0.05 (*), p ≤ 0.01 (**). Error bars represent standard deviation
