b2815 Tissue Engineering and Nanotheranostics “9.61x6.69”4 Tissue Engineering and Nanotheranosticswound.^15 The immune cells recruit resident satellite cells (SCs) to
begin forming new myoblasts. The ideal healing resolution of remod-
eling the scar tissue, fusion of new myocytes, and reinnervation are
prevented in VML injuries due to the large amount of scar tissue.^15 As
a result, the scar remains intact and any tissue distal of the wound is
denervated.^15 Primary concerns in the clinical treatment of VML inju-
ries are wound closure, pain reduction, and promotion of healing. A
common surgical method to achieve these goals utilizes muscle flaps.^11
If the injury is small enough, a muscle flap can be cut in the nearby
muscle and repositioned in numerous ways to cover the wound.^16
Larger defects may require harvesting thin muscle grafts from a differ-
ent donor site.^16 This treatment provides the wound site with a cover-
ing to help protect the injury, preformed vasculature to ensure
adequate blood supply, and an additional source of cells for regenerat-
ing the lost muscle tissue.^16 Although this method is well established
and often effective for closing wounds, lack of suitable donor sites and
the necessity of causing another injury make it less than ideal. Skin
grafting procedures may also be necessary once the underlying muscle
damage has been addressed. When the wound is closed and has devel-
oped mechanical integrity, bracing and physical therapy can be used to
mitigate any resulting disability.^17 Cellular engineering strategies could
be applied to many of these problems, but the strategies used will be
dependent on the type of disease or injury. For example, VML may
eventually be treated by off-the-shelf muscle grafts engineered in vitro.
However, this technique will require surgery, and will likely not be
effective in systemic disorders such as DMD. Instead, dystrophies may
be addressed through a cell injection approach, conditioning and
expanding cells in vitro and injecting them into circulation to home in
on their target sites throughout the body. Current tissue engineering
approaches from 3D constructs to cell injection are discussed later
in this chapter.
2. New Muscle: Myogenesis and Muscle Regeneration
The body has a remarkable ability to not only structure its connective
tissues during embryogenesis, but also maintain and repair them as an
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