Joris van Dongen

346 Chapter 15 internal disk with three holes of 1.4 mm. The absence of a central hole frequently resulted in regular blocking due fibrotic tissue in lipoaspirate. Furthermore, the original fractionator was reusable which is, with respect to patient safety, less safe as a disposable device. In chapter 4 , a disposable one-hole fractionator was developed and compared to the original reusable three-hole fractionator regarding histological composition, composition based on CD marker expression, the ability of cells to form colony forming units and the number of cells isolated as well as their viability. No differences were observed in histological composition as well as composition based on CDmarker expression between tSVF isolated by both types of fractionators. Moreover, the number of cells enzymatically isolated from tSVF as well as their viability and ability to form colony form units was comparable between both types of fractionators. Additionally, the number of procedures that blocked during process was lower when the disposable one-hole fractionator was used. This study demonstrated the improved usability of the disposable one-hole fractionatorwithout losing its efficiency in isolating tSVF compared to the original reusable three-hole fractionator. One of the main advantages of tSVF isolated by means of the FAT procedure was the increased number of regenerative cells in one ml of tissue in comparison with unprocessed lipoaspirate. In this way, a higher number of regenerative cells can be injected in small volume areas such as small joints suffering fromosteoarthritis. Recently published studies show that SVF or ASCs can be effective in reducing inflammation of chondrocytes, one of the keyplayers in osteoarthritis. In chapter5 ,we have investigated if tSVF isolated by means of the FAT procedure is able to reduce the pro-inflammatory state of chondrocytes in vitro . In this study, the proliferation of chondrocytes and production of sulphated glycosaminoglycans (sGAG) by chondrocytes co-cultured with various ratios of enzymatically isolated tSVFcellswas studied.Moreover, the expression of interleukin-1 β (IL-1 β ) and cyclo-oxygenase 2 (COX2) during co-culture of tumor necrosis factor- α (TNF- α ) stimulated chondrocytes with enzymatically isolated tSVF cells was investigated. A significant increase in number of chondrocytes was noted after twenty-one days of culture when chondrocytes were co-cultured with tSVF in various ratios, especially in ratios 50/50 and 25/75. Chondrocytes co-cultured with tSVF in ratio 25/75 were functional because the amount of sGAS produced was comparable to single cultured chondrocytes. Moreover, expression of IL-1 β and COX2 by TNF- α stimulated chondrocytes was significantly reduced by tSVF. These in vitro results show the anti-inflammatory and proliferative effect of tSVF on chondrocytes. The main goal of this thesis was to study skin rejuvenation by tSVF on skin alterations caused by ageing and dermal scarring. Skin quality decreases over time due to ageing, fibroproliferative diseases of the skin or scarring. These causes can be divided