Joris van Dongen

345 English summary ENGLISH SUMMARY In chapter 2 , a systematic review of all commercially available intra-operative enzymatic and mechanical isolation procedures of stromal vascular fraction (SVF) was performed. Pubmed, EMBASE (OvidSP) and the Cochrane central register of controlled trials databases were searched until September 2016. Studies validating SVF isolation procedures based on cell yield, viability of nucleated cells, composition of SVF, duration, cost and characteristics of procedures were included. In total, thirteen studies evaluating eighteen procedures were included. None of the procedures in terms of cell yield, viability of nucleated cells or composition of SVF could be designated as preferred method due to a large heterogeneity in validation methods. However, major differences in duration and costs between enzymatic and mechanical procedures exist. In general, enzymatic isolation procedures are time-consuming and expensive due to the use of non-autologous material e.g. enzymes or animal derived products and disposable components. Mechanical isolation procedures are less time-consuming and less expensive because only shear stress is used as dissociation method. Moreover, mechanical isolationprocedures result ina tissue like SVF(tSVF)with intact intercellular communications including the extracellular matrix, while enzymatic isolation results in a single cell suspension of SVF (cellular, cSVF). Therefore, mechanically isolated tSVF has been used in our prospective randomized clinical trials. In chapter 3 a mechanical isolation procedure, the so-called Fractionation of Adipose Tissue (FAT) procedure was developed and validated to isolate tSVF from harvested lipoaspirate. The FAT procedure consists of three consecutive steps: centrifugation followed by fractionation and subsequently centrifugation. The obtained tSVF was validated based on viability, histological composition and presents of adipose derived stromal cells (ASCs). ASCs were characterized based on function, phenotype and ability to form colony forming units. All these aforementioned protocols to perform and validate the FAT procedure were presented in an overview in chapter 6 . The FAT procedure was able to concentrate tSVF tenfold containing mainly extracellular matrix and vasculature by destructing adipocytes. Viability of tSVF was up to 100%. ASCs isolated from tSVF were not affected by the FAT procedure and showed a comparable multilineage differentiation capacity, CD expression as well as ability to form colonies in comparison with non-processed ASCs. Hence, the FAT procedure was able to isolate tSVF preserving all regenerative components in a small volume within twenty minutes and is therefore suitable for intra-operative use. Although the FAT procedure was efficient in isolating tSVF, some improvements could be made to improve its usability. The original fractionator contained an off-centered