gov [9]). Current standard clinical strategies for soft tissue augmentation primarily include the use of synthetic implants and fillers. However, various complications derived from the foreign body, such as capsular contracture or displacement, lead to implant removal or replacement at a relatively high rate. Free fat transfer gives unpredictable results, where graft reabsorption can vary between patients,

although it seems to work well for small defects correction [4]. Mixing autologous ASCs with a portion of suctioned fat and injecting subcutaneously back into the GSK J4 datasheet target site is another strategy which is recently used to overcome these problems and to provide a “living scaffold” for stem cells [27]. It has become crucial to develop safe and reproducible protocols for the extraction and storage of ASCs that can adhere to the strict European regulation concerning the Advanced Therapy Medicinal Products (ATMPs). Storage of the SVF could be seen as an intermediary GMP product to be needed in the future for many differentiation protocols to be developed. One step in this direction

is the possibility to store frozen cells for long periods of time in liquid nitrogen and to be able to use them after thawing, i.e. for cell amplification and/or differentiation. We show here that SVF extracted cells can be frozen and thawed without Ku-0059436 supplier losing their ability to grow and differentiate in mesenchymal-specific lineages. Only a few studies examined the role of frozen storage of adipose tissue. One of them has recently described the storage of entire adipose tissue at various temperatures for periods longer than 1 year to see whether the tissue was still capable of adipogenic differentiation. Cells isolated from the tissue proved to be a reliable source of human ASCs and adipocytes [11]. Early research studies described a domestic −18 °C storage of adipose tissue for 2 weeks. Injection of fat tissue in nude mice demonstrated the

survival of this tissue as compared to a control group of non-frozen tissue [19]. A simple Dipeptidyl peptidase freezing technique was recently used by storing fat tissues at −196 °C in liquid nitrogen for up to 8 days demonstrating a good maintenance of mitochondrial metabolic activity in the frozen grafts [12]. Remarkably, in both experiments fat tissue samples were frozen without the addition of a cryoprotective agent. Another study reported the use of a cryoprotective agent to better save and keep viable tissues after thawing [26]. Nevertheless, we have to consider that adipose tissue is the source of ASCs responsible for the biological effect observed in regenerative medicine. Thus, for long conservation purposes we should only consider the stromal vascular fraction (SVF) by isolating it from the carrier tissue.