Joris van Dongen

151 The power of fat and ASCs for scar treatment: a review During development, adipose tissue is derived from the mesodermal germ layer. The mesenchymal stem cells (MSC) that reside in the mesoderm differentiate into adipocytes to formadipose tissue. However, after the embryogenic formation of adipose tissue, some of the mesenchymal stem or stromal cells remain. In the adult situation, these MSC are the previously mentioned ADSC. In the adipose tissue, ADSC reside around the vasculature 22-25 . Furthermore, ADSC retain the ability to differentiate into adipocytes, thus functioning as a source to regenerate adipose tissue 26 . LIPOFILLING AS A METHOD TO TREAT SCARS As stated above, lipofilling is beneficial for skin and scar treatment. In recent years, a limited number of retrospective and prospective supported previous anecdotal clinical observation (Table1). Clinical studies Clinical efficacy of lipofilling in scar areas is determined either by improvement of the appearance of a scar, such as size, thickness, stiffness, discoloration of the scar. In the case of painful scars, this effect can also be measured by a decrease in pain. In the first subsection of this summary of clinical studies, the focus lies on the ability of lipografts to improve several of the above mentioned appearance of scars, whereas in the second subsection focus lies on the ability to reduce pain. Scar appearance Macroscopically, scars are characterized by different appearance than the surrounding skin: discoloration, stiffness and roughness are features of scarring. In clinical studies, different outcome measures are used to quantify the degree of scarring on a macroscopic level. The first method often used to assess scar severity are patient or observer rated grading scales, in which several aspects of scarring (e.g. color, stiffness, thickness, irregularity) are rated. A second method is to use measuring devices for skin elasticity or dermal pigmentation. The efficacy of lipofilling to improve scar appearance has been investigated in sixteen case reports or clinical trials 6,8,27-38 (Table 1a).