As a filler, hyaluronic acid has multiple properties and can be injected into different parts of the body. However, being a foreign substance, there is always a chance of allergy or rejection, and the effects usually only last for a few months to a year. Is there a natural and long-lasting substance? The answer may be autologous fat! Autologous fat transplantation has natural and long-lasting effects, and does not cause rejection, making it a perfect filler.
The earliest literature on autologous fat transplantation dates back to 1893 when a doctor transplanted fat from the arm to a depression on the face caused by tuberculosis. Since then, there have been more and more cases of autologous fat transplantation, but at the same time, it was found that more than half of the transplanted fat was absorbed by the body and could not survive. As a result, the success rate and effect of fat transplantation were not ideal, and fewer and fewer people underwent this surgery.
Until the past decade, research found that if the stem cells in fat can be extracted and concentrated, then mixed with fat for injection, it can increase its survival rate. This discovery has brought a breakthrough in autologous fat transplantation!
Does fat have stem cells? In addition to bone marrow and placenta, stem cells in fat are called “adult stem cells.” Although adult stem cells cannot differentiate into different types of cells like pluripotent and multipotent stem cells, they can differentiate into designated cells, such as vascular cells, fat cells, and fibroblasts. Cells that were previously discarded when extracting fat are now being researched.
Today, most stem cell research is on adult stem cells because this is the only “differentiable cell” that adults can obtain, and bone marrow and fat tissue in adults are where most of the body’s stem cells are stored. After years of development, the application of autologous fat stem cells has expanded, from fat transplantation to injection into ischemic tissue of the heart, injection into patients with degenerative arthritis, or injection into degenerated intervertebral disc cartilage. The techniques of stem cell extraction, refinement, purification, preservation, and injection have all improved significantly. Now doctors are attempting to extract stem cells from fat tissue, mix them with fat as a filler for injection. This technique is called “cell-assisted lipotransfer.”
Although there has been some breakthrough in techniques, it will take a long time for widespread application. The most significant factor is the fat survival rate, which in a large study (compared to fat transplantation without stem cells) has increased from 45% to 60%. This number still has a way to go before reaching the “perfect filler.”