The purpose of this study is to observe whether the transplantation of autologous stromal vascular fraction (SVF) in adipose tissue is safe and its effect on improving the texture and contracture of skin grafting.

Reconstruction of large scale skin defect is still a challenge for clinical surgeons. The application of skin grafting works as an important choice, however, the strong contracture and poor appearance limit its wide application in scar repair. The stromal vascular fraction (SVF) of adipose tissue is a group of heterogeneous cells including multipotential mesenchymal cells, preadipocytes, endothelial cells, fibroblasts, macrophages and smooth muscle cells. Previous researches have reported that SVF could secrete various angiogenic growth factors in vitro and enhance neovascularisation of ischaemic tissue in vivo. The Adipose-derived Stem cells in the SVF are multipotential stem cells which have the ability to regenerate, while differentiating to become adipose tissue and help to improve the texture of the grafted skin. Besides, SVF is easy to be harvested in large numbers with less donor injury and can be used directly after isolation without in vitro culture, which makes it a good alternative for regenerative medicine.This study is to observe the effect of autologous SVF on improving the texture and contracture of skin grafting.

Patients requiring skin graft of 2 symmetry parts of the body between the age of 3 and 70 years will be enrolled and randomized into two groups, named as the experimental group with SVF transplantation and the control group with no cell transplantation. Patients from the experimental group will have a fat aspiration on the surgery day. The adipose tissue in abdomen or thigh will be digested at 37 °C for 60 min with 0.2% collagenase IV. After filtration and centrifugation, mature adipocytes are separated from the cell pellet. The pellet then is treated with erythrocyte lysis buffer twice to remove red cell fragment. The harvested pellet is SVF. The SVF will be resuspended in saline and transplanted between the grafted skin and the wound with 1 million cells for 1 cm2 area. Skin thickness, texture, contracture and colour will be observed to measure the effect of SVF on skin grafting post treatment.

Inclusion Criteria:

• With symmetrical scar or soft tissue deficiencies requiring skin graft therapy.
• Age of 3 to 70.
• Have no underlying disease except skin scar deformity.
• Have enough healthy donor site skin for both sides of receiving area.

Exclusion Criteria:

• Not fit for skin graft treatment;
• Evidence of infection, ischemia, ulcer or other pathological changes within the targeting area which defined as not suitable for skin grafting; or history of delayed healing, radiational therapy;
• Significant renal, cardiovascular, hepatic and psychiatric diseases;
• Significant medical diseases or infection (including but not limited to the carrier of hepatitis B virus or HIV);
• BMI >30;
• Alcohol abuse
• History of any hematological disease, including leukopenia , thrombocytopenia, or thrombocytosis;
• Evidence of malignant diseases or unwillingness to participate.