Joris van Dongen

128 Chapter 6 single cells tend to migrate out of the injection area within the first 24h after injection. 15 In tSVF, the ASCs are still attached around vessels and embedded in the extracellular matrix, which might result in higher retention rates. The fractionation of adipose tissue procedure (FAT) yields the tSVF in a non-enzymatic manner. 16 This tSVF is an enrichment of blood vessels, extracellular matrix as well as ASCs by the disruption of adipocytes. The ASCs isolated from the tSVF are not affected in their function, phenotype and colony formation capability. Moreover, the high amount of extracellular matrix present in the tSVF may serve as a natural scaffold to deliver and guide cells ( e.g. ASCs) in their proliferation as well as differentiation. The extracellular matrix in tSVF contains a large number of vessels as well, which can augment vascularization and perfusion. These latter two are important for appropriate wound healingwhich is frequently impaired in patients suffering fromsystemic diseases such as diabetes. Therefore, the isolated tSVF by the FAT procedure might be suitable for skin tissue engineering in vivo to augment (diabetic) wound or ulcer healing. Several clinical studies have already shown the beneficial influence of adipose tissue or the stromal vascular fraction on dermal wound healing. 8,17-19 By virtue of the FAT procedure, which is easily standardized, we previously showed that the tSVF composition is subject to interdonor variation. The clinical application of tSVF demands standardized characterization methods. The existing standardized endpoints and methods to validate the isolation procedures and their cellular product are difficult to perform because these methods are time-consuming, complex and expensive. Thus far, no quick intraoperative characterization methods are available. Therefore, we propose easier standardized methods to validate the isolation procedures and their cellular product. MATERIALS Liposuction of adipose tissue 1. Human subcutaneous liposuction derived adipose tissue. 2. Scalpel. 3. Modified Klein’s solution (per 500 ml of saline, 20 ml of lidocaine, 2% epinephrine 1: 200,000 and 2 ml of bicarbonate). 4. Sorenson type lipoharvesting cannula (Tulip, Medical Products, San Diego, California). 5. 50 ml Luer Lock syringe.