Autologous fat grafting is the most popular item in plastic surgery in recent years, widely used for facial rejuvenation and soft tissue filling, in addition, autologous fat grafting for breast augmentation has been a popular item among candidates over the years, with the advantages of no scars, no complications related to allogeneic synthetic materials that may accompany, liposuction body sculpture and breast augmentation completed at the same time, killing two birds with one stone.
The current problems of autologous fat transplantation.
1, unpredictable effect
2. Absorption of transplanted fat
What are the reasons for the problems?
The lack of fat stem cells in the absorbed fat is one of the important reasons.
The left side is normal adipose tissue with 100% fat stem cells extracted; the right side is the aspirated fat with half the number of stem cells in normal fat.
Why are there fewer fat stem cells in the aspirated fat?
1.Fat stem cells are left around the large blood vessels in the liposuction area.
2.Some of the fat stem cells are released into the liposuction fluid.
Are fat stem cells important for the survival of transplanted fat?
Adipose stem cells can promote the survival of transplanted fat. Adipose stem cells can secrete some pro-angiogenic factors to promote the survival of fat, in addition, adipose stem cells can participate in the formation of new blood vessels and can differentiate to adipocytes. Therefore, the low number of adipose stem cells in the transplanted fat is not conducive to the survival of the transplanted fat.
The above picture suggests that ASC are adipose stem cells that can differentiate into adipocyte or participate in vessel formation.
What does CAL mean?
CAL stands for Cell-assistedlipotransfer. which means cell-assisted fat grafting. Studies have shown that the addition of fat stem cells can improve the survival rate of transplanted fat. Extracting fat stem cells from freshly aspirated fat, adding them to the transplanted fat, and then implanting them into the body is called cell-assisted fat grafting.
How are fat stem cells extracted from the aspirated fat?
The cells obtained from the aspirated fat after digestion with 0.075% collagenase, centrifugation, red blood cell lysis, washing, and filtration are called stromalvascularfraction (SVF), of which about 35% are adipose stem cells, 15% are endothelial cells, and 37% are leukocytes.
KotaroYoshimura and CAL
KotaroYoshimura, a Japanese, is a professor of plastic surgery at Kyorin University and the head of plastic surgery at Tokyo Medical University in Japan. He was the first to introduce the concept of CAL, which is safe because he added SVF cells that have not been expanded by in vitro culture. It is equivalent to autologous component transfusion, where one draws one’s own blood, extracts a certain component, and then transfuses it back into the body.
In vitro culture of stem cells for clinical use has high requirements
There is a set of national requirements that need to meet a set of technical access to biological drugs. The requirements include environment, instruments and equipment, personnel, reagents, process, quality control, etc. The safety testing after cell expansion is particularly important.
Tumorigenicity of amplified passaged adipose stem cells
Researchers have found that after successive generations of adipose stem cells (more than 10 generations), more than 30% of the cells showed chromosomal deformation and individual oncogenes were expressed, and some of them formed tumors when transplanted into nude mice.
Autologous fat breast augmentation
There are many factors affecting the effect of autologous fat transplantation breast augmentation: liposuction process, treatment of fat, fat injection, the whole process should be non-invasive to reduce the damage of fat cells during the whole process, adding fat stem cells can promote the survival of transplanted fat, but if no attention is paid to other aspects, the surgical effect will not be good. In the process of autologous fat injection breast augmentation, the injection link is the heaviest, if the injection becomes a mass, it will lead to complications such as nodules, lump formation and calcification in the breast. Autologous fat grafting may seem simple, but it is not easy to do well, so the American Society of Plastic Surgeons recommends that autologous fat grafting be used cautiously for breast augmentation because the results of the procedure depend mainly on the physician’s skill, experience surgeon-dependent).