Joris van Dongen

347 English summary into two types of processes: physiological process (ageing) or pathological process (fibroproliferative diseases or scarring). Many studies have described a potential effect of lipofilling on skin rejuvenation whether decrease in skin quality has a physiological or pathological cause. In chapter 7 , an extensive overview is given of the literature regarding the anti-scarring effect of lipofilling in both clinical and animal studies. This review underlines the lack of well-designed prospective randomized clinical trials in the field of regenerative plastic surgery, especially when lipofilling or any component of adipose tissue e.g. ASCs, SVF is used as anti-scarring treatment. However, many case reports and retrospective studies suggest a clinical effect of lipofilling on dermal scars in terms of softening of the skin, improvement in color and thinning of the skin. Although formal proof derived from randomized prospective trials is lacking, data from these case reports and clinical studies has led to the acceptance of lipofilling as a treatment of burn scars nowadays. The underlying mechanism can be ascribed to three main processes, which are involved in dermal wound healing as well: stimulation of angiogenesis, remodeling of extracellular matrix and immune modulation. These cellular processes are stimulated byASCs through secretion of growth factors, cytokines and proteins. Due to a lack of well-designed prospective randomized clinical trials, we designed a prospective randomized double-blinded placebo-controlled multi-center clinical trial investigated the effect of tSVF on early wound healing in order to prevent or reduce scar formation. In chapter 8 , tSVF was produced by means of the FAT procedure and injected after a breast reduction,while the contralateral breast served as placebo control. In total, 34 female subjects were treated (34 versus 34). The results of this study showed a significant improvement in scar appearance after six months. Many of the included patients noticed a faster healing of the wound in the first weeks postoperative. Twelve months postoperative scar appearance was comparable between the tSVF and control group. This indicates that tSVF probably plays only a significant role in early wound healing rather than have a role as an anti-scarring treatment. In chapter 9 , the effect of autologous lipofilling in combination with platelet-rich plasma (PRP) on ageing related skin changes was studied in a prospective randomized placebo-controlled clinical trial. In this study, PRP was added to stimulate ASCs present in lipofilling in order to enhance the regenerative effect by autologous lipofilling. Skin improvement was measured using the cutometer to measure elasticity and a questionnaire to evaluate the opinion of participating subjects as well as their return to work in days. In total, 32 female subjects were treated with either autologous lipofilling with platelet rich plasma or autologous lipofilling with placebo control. After twelve months of follow-up, no significant difference was noted in skin elasticity