Condensation of tissue and stem cells for fat grafting.

Aspirated fat contains unnecessary components such as water, oil, and blood cells. For better outcomes, tissue purification and condensation are useful, especially when injection volume to the recipient site is limited. Because aspirated fat is relatively poor in adipose-derived stem/stromal cells (ASCs), ASC condensation seems important for obtaining better regeneration and retention. Reducing tissue volume by removing some adipocytes or supplementation of stromal vascular fraction or ASCs can increase the ASC/adipocyte ratio in the graft. Clinical results of ASC supplementation remain controversial, but ASC condensation seems to lead to expanding applications of fat grafting into revitalization of stem cell-depleted tissue.