Adipose Stem Cell and Its Clinical Application

Jeong, Jae Ho

Abstract

At the last decade of 20th century, the existence of Adipose- derived stem cells(ASCs) within fat tissue was discovered by a research team of Plastic Surgery in Pittsburgh University. With this historic event, the clinical application of adult stem cell became practical. Before the discovery of ASCs, many scientist have been working on bone marrow stem cells(BMSCs) with difficult problems of proliferating cells without compromising natural stemness in short period. The greatest advantage of ASCs over other types of adult stem cells is its large number when we harvest primarily. The number of stem cells within adipose tissue reaches more than hundreds of times compared with BMSCs contained in the same amount of bone marrow. The major role of 'regenerative medicine' in 21st century is based on cell therapy and ASC is going to take the core position. Clinical fat graft, as fat injection, have been performed for one-hundred years and the mechanism of fat graft survival is not clearly understood. With the accumulation of knowledges related with ASCs, it becomes obvious that ASCs have great implications on clinical fat injection and the role of stem cells on fat graft survival is now actively under investigation. Many clinicians have their own favored methods of increasing fat graft survival but many of them are not based on scientific evidences. In this paper, I'd like to emphasize several scientific facts and popular biases which many plastic surgeons believe them as scientific facts. Method of fat harvesting such as liposuction and surgical excision affects fat graft survival because of the predisposition of ASCs near vascular structure within fat tissue. Plastic surgeons believe fat graft donor site is important for graft survival but literature review shows no scientific evidences. Rather, fat graft survival is greatly different according to the recipient sites and it have been proven by many scientists. Detailed techniques of handling fat after harvesting, such as size of suction cannula, degree of negative pressure for liposuction, speed of centrifugation, washing as well as method of fat injection, may or may not influence the graft survival. We may greatly increase the fat graft survival by changing basic concepts of fat grafts as below; (1) cell-assisted lipotransfer, (2) grafting cultured preadipocytes, and (3) fat graft as fat cell suspension. It is important to know the characteristics of ASCs for successful clinical application. There are several unique features of ASCs as a kind of adult stem cells which I believe a common characteristic of mesenchymal stem cells(MSCs). Cellular plasticity is one of the most important feature of ASCs as in other adult stem cells and the cells also have a special function of immune modulation and immunosuppression. Strong angiogenic potential is another important nature of ASCs. In many reports, ASCs are known not only to be differentiated into osteoblast, chondrocytes, vascular endothelial cells, but also to be cardiomyocytes and neuronal cells. In conclusion, the new knowledge of ASCs is going to impact on the regenerative medicine. To take the advantage of this new type of cells and utilize the cells, we need to understand the function of ASCs and future possibilities of ASCs. We plastic surgeons continue to stimulate the our curiosity and creativity, as well as our clinical inspiration.