Comparison of survival and effectivity of cryopreserved adiposed derived stem cell, stromal vascular fraction, fat graft and tissue cocktail in rats

Fat grafts are a safe, natural filler material, which can be taken from the person himself. However, partial necrosis of the transplanted fat is inevitable due to the sensitivity of fat cells to hypoxia. With magnetic resonance, it has been shown that the graft maintains, preserving only 55-70% of the transplanted volume. Thus, multiple procedures are often required to achieve treatment goals, resulting in both extra cost and increased morbidity for the patient. In order to reduce these undesirable effects of fat grafting, at the first session of liposuction, a portion of lipoaspirate can be taken and stored at low temperatures so that it can be reused when the patient needs additional treatment, that is, so called cryopreservation. However, in the literature there is no single opinion about the cryopreservation protocol, survival of the preserved tissue and the effect of thawed tissue in the transplanted area. In our study, 48 Wistar rats (male, 200-500 grams) were divided into 6 groups with 8 subjects in each group. Inguinal adipose tissue on one side of each rat was excised first, and after, from that tissue we got fat graft, adipose tissue derived stem cell (ADSC), stromal vascular fraction (SVF) and tissue cocktail. As a cryopreservation protocol, materials were first applied to 43°C with 5% CO2 for 1 hour as a heat shock, then stayed in 37°C cell culture incubators for 3 hours. After 3 hours, materials stayed at 4°C for a 10 minutes with 10% DMSO+FBS solution, then cooled and stored -80°C (-1°C/min) as the final temperature for 3 months. At the end, each material was rapidly thawed in a 37°C hot water bath and transferred autologously to the contralateral inguinal adipose tissue of the rats. Morphological examination with H&E and immunohistochemical evaluation with VEGF and Ki67 showed significant differences between the control group and the other groups (p>0.0001). VEGF and Ki67 staining of the fat graft and tissue cocktail was observed to be significantly higher than in the ADSC, SVF, ADSC and SVF groups (p>0.0001). In addition, necrosis and giant cells were observed in the fat graft and tissue cocktail groups. Fat graft and tissue cocktail groups may have shown higher results as a staining, but we found the ideal morphology for cell survival, angiogenesis and adipogenesis in the ADSC, SVF, ADSC and SVF groups. As a result, the survival of cells decrease after cryopreservation in relatively larger tissues such as fat graft and tissue cocktail. It is thought that freezing the cells in the adipose tissue that regulate, form and support angiogenesis and adipogenesis gives better results than freezing the whole tissue. Resistance of the stem cells to cryodamage ensure that more cells maintain their viability, so that the graft volume will be preserved, as well as with the formation of new vessels and adipocytes. In clinical practice, the use of these advantages will both increase the effectiveness of the treatment and be effective in the comfort of the patient during the treatment.