Joris van Dongen

186 Chapter 8 tissue-derived stromal cells (ASCs), fibroblasts, endothelial cells, smooth muscle cells and pericytes. 14 If prepared by mechanical fractionation, SVF also contains micronized adipose tissue devoid of adipocytes i.e. extracellular matrix maintains all relevant adhesions and is then referred as tissue-SVF (tSVF). 15 The extracellular matrix is an important and often underestimated therapeutic component in SVF and functions as a natural slow release scaffold of cytokines and growth factors. 12 Besides, extracellular matrix affects cell behavior via biochemical signaling as well as via mechanical signaling such as topography and stiffness. These latter instructive cues lack in enzymatically prepared SVF. 16 In this prospective clinical study, tSVF is evaluated for its potential to increase dermal wound healing of a post-surgical wound to subsequently suppress scar formation. 17-19 A bilateral reduction mammoplasty was used as a clinical model to test both the safety and efficacy of tSVF in wound healing in a healthy female population. MATERIAL & METHODS Study overview This study was conducted as a multi-center, double-blind, randomized, placebo- controlled clinical trial in the Netherlands. The study was carried out in compliance with theDeclaration of Helsinki and approved by the national medical ethics committee (CCMO) of the Netherlands (National legislator trial code: NL55651.000.16, Dutch trial register code: NTR5719). All subjects provided written informed consent prior to start of the study. Patient population and randomization A sample size calculation estimated the number of subjects required for this study at 34. Due to a higher number of drop-outs than expected, 6 subjects were additionally included with a total number of participating subjects of 40. In- and exclusion criteria are summarized in table 1. Subjects who underwent a bilateral wise pattern reduction mammoplasty were included and each breast was randomly divided in one of the following groups: tSVF injection or saline injection. Patients were followed for 1 year and blinded during the entire study. Patient enrollment started at June 2016 until the study ended at June 2020.