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www.PRSJournal.com 687e D Feng Lu’s laboratory continues to lead the way in advancing our understanding of the regenerative potential of adipose tissue. In this most recent work, Zhang, Cai, and colleagues present a mouse study on graft volume retention and histology of stromal vascular fraction gel versus Coleman fat. They report that stromal vascular fraction gel grafts induce more rapid angiogenesis, host cell–mediated adipogenesis, and macrophage infiltration, thereby enhancing volume retention. By analyzing the tissue at multiple time points, the authors elucidate the “life cycle” of avascular fat grafts in greater detail. Their findings support and shed light on the “regenerative theory” from the Yoshimura laboratory.1 According to the regenerative theory, mature adipocytes play a minimal role, whereas adiposederived stem/progenitor cells induce tissue regeneration.2 In addition, maximizing the surface area–to-volume ratio optimizes oxygen diffusion relative to metabolism, allowing for greater survival of adipose-derived stem/progenitor cells during imbibition.3 Therefore, eliminating the adipocytes decreases the graft’s volume and oxygen demand without sacrificing its regenerative potential. Surgeons have hesitated to adopt this adipocyte-free grafting because of the regulatory and scaling burdens associated with enzymatically digesting adipose tissue and purifying adiposederived stem/progenitor cells. The simplicity of producing stromal vascular fraction gel may circumvent these limitations. Indeed, the authors report that they have already conducted a clinical trial of stromal vascular fraction gel versus Coleman fat for facial augmentation; I look forward to seeing the results. I encourage the authors and other scientists not to limit the role of adipose tissue to volume filling. Adipose-derived stem/progenitor cells have demonstrated tremendous regenerative capabilities in terms of inducing angiogenesis4 and peripheral nerve regeneration5 and reversing rheumatoid arthritis,6 osteoarthritis,7 dermal atrophy,8 fibrosis,9 Peyronie disease,10 urethral strictures,11 and stress urinary incontinence.12 The clinical translation of these findings has stalled, largely because of the burdens associated with purifying adipose-derived stem/progenitor cells. Stromal vascular fraction gel may serve as an alternative method for adipocyte-free grafting, but additional research is necessary.