Joris van Dongen

104 Chapter 5 ABSTRACT Introduction Enzymatically isolated stromal vascular fraction as a treatment for osteoarthritis has already shown to be effective. Yet, the use of enzymes for clinical purpose is highly regulated in many countries. Mechanical preparation of SVF results in a tissue-like SVF (tSVF) containing intact cell-cell connections including extracellular matrix and is therefore less regulated. The purpose of this study was to investigate the immunomodulatory and pro-regenerative effect of tSVFon inflammatory chondrocytes in vitro . Materials and Methods tSVF was mechanically derived using the Fractionation of Adipose Tissue (FAT) procedure. Characterization of tSVF was performed e.g. cellular composition based on CDmarker expression, colony forming unit and differentiation capacity after enzymatic dissociation (from heron referred to as tSVF-derived cells). Different co-cultures of tSVF-derived cells and inflammatory chondrocytes were analysed based on production of sulphated glycoaminoglycans and anti-inflammatory response of chondrocytes. Results Characterization of tSVF-derived cells mainly contained ASCs, endothelial cells, leukocytes and supra-adventitial cells. tSVF-derived cellswere able to form colonies and differentiate into multiple cell lineages. Co-cultures with inflammatory chondrocytes resulted in a significant increase of the total number of chondrocytes as compared with cultures of chondrocytes alone (p<0.05). IL-1 β and COX2 gene expression was upregulated inTNF α -treated chondrocytes.After treatment with (conditioned medium of ) tSVF-derived cells, IL-1 β and COX2 gene expression was significantly reduced (p<0.01). Conclusion Mechanically derived tSVF stimulates chondrocyte proliferation while preserving the function of chondrocytes. Moreover, tSVF suppresses chondrocyte inflammation in vitro . This pro-regenerative and anti-inflammatory effect shows the potential of tSVF as a treatment for osteoarthritis.