The science of autologous fat grafting: views on current and future approaches to neoadipogenesis.

LEARNING
OBJECTIVES: The reader is presumed to have a broad understanding of plastic surgical procedures and concepts. After studying this article, the participant should be able to: 1. Describe the current clinical applications and limitations of autologous fat grafting. 2. Identify the important physiological steps and molecular pathways of neoadipogenesis. 3. Cite current in vitro and in vivo models for the analysis of fat grafting techniques. Physicians may earn 1 AMA PRA Category 1 credit by successfully completing the examination based on material covered in this article. The examination begins on page 322. ASAPS members can also complete this CME examination online by logging on to the ASAPS Members-Only website (http://www.surgery.org/members) and clicking on "Clinical Education" in the menu bar. Autologous fat transplantation has become a well established and frequently applied method of soft tissue augmentation for both cosmetic and reconstructive indications. There is no consensus, however, about the best fat grafting technique, nor is there reproducible data regarding its durability. The most significant drawback to autologous fat grafting remains its largely unpredictable rate of resorption. A thorough understanding of the developmental biology and molecular regulation of adipogenesis and adipocyte survival is critical to optimizing the fat grafting technique. Consequently, numerous in vitro and in vivo studies on fat graft viability have recently been undertaken. Here, we discuss the latest advances in the basic science of adipogenesis, adipocyte viability, and its clinical application to fat grafting, arguing that the data produced by in vitro and in vivo studies still fail to produce a clear picture of the required components for successful, consistent, and durable fat transplantation; however, it is undetermined if this lack of clarity may simply be a lack of systematic scientific data acquisition or if these findings truly reflect the biology of neoadipogenesis. As a first step in strengthening autologous fat grafting scientific data collection, we recommend that a collective, multidisciplinary, multicenter effort be undertaken to establish in vitro and in vivo models of neoadipogenesis that are clearly reproducible from one investigator to another. With the implementation of systematic scientific approaches to the study of neoadipogenesis, we anticipate the future of autologous fat transplantation for correction of soft tissue volume loss to be extremely promising.