Figure 7.

Large-scale organized structures of contractile myofibroblasts (MFB) are the cellular origins of wound contraction and scar formation in skin and peripheral nerves. A: In ungrafted skin wounds, large numbers of MFB form a thick cellular capsule. The long axes of MFB are oriented parallel to the plane of the epidermis. Elementary forces applied by each MFB sum up to a significant resulting force that contracts the injury site. Collagen fibers synthesized by MFB are also oriented along the same direction, leading to scar synthesis. B: In skin wounds grafted with DRT, MFB migrate inside the scaffold, bind on its surface and become randomly oriented. The resulting macroscopic contraction force is much smaller compared to the ungrafted wound. C: In ungrafted transected peripheral nerves, large numbers of MFB form a thick cellular capsule in the outer surface of the nerve regenerate. These MFB are oriented circumferentially around the nerve perimeter, generating a “pressure cuff” effect that compresses the neural tissue along the radial direction. D: In transected peripheral nerves grafted with porous collagen conduits based on DRT, the MFB capsule is much thinner and the resulting neural tissue synthesized is much larger in mass and axon content.