Cell-assisted lipotransfer

Autor: F. M. Lampert, G. B. Stark, Gerd Antes, Buroh S, Edith Motschall, S. Grabin
Rok vydání: 2014
Předmět:
Zdroj: Deutsches Arzteblatt international. 112(15)
ISSN: 1866-0452
Popis: For several decades now, the widespread introduction of clinical stem-cell therapies has been said to be just around the corner. Stem-cell research continues to be a highly dynamic field, yet there is still only one routine and widespread treatment employing stem cells, i.e., hematopoietic stem-cell transplantation (1). A number of therapeutic procedures that are claimed to exploit various properties of “;stem cells” are now being promoted, sometimes aggressively, in both the scientific literature and the lay press. Increasingly, direct advertising to potential patients is being broadcast over the Internet (2– 4). Stem cells from fatty tissue (adipose-derived stem cells, ADSC) are a relatively recent member of the stem-cell family. ADSC are an adult mesenchymal stem-cell population with many advantageous features for potential clinical use. They are plentiful in human fatty tissue, and they can easily be obtained by liposuction. Their phenotypes and functions closely resemble those of stem cells from bone marrow. They have been shown to be able to differentiate into many different types of cells, including chondro-, osteo-, adipo-, myo-, and neurogenic lines, as well as endothelial cells (5). Their accessibility and versatility make them appealing not only to researchers and clinicians designing new treatments, but also to physicians who see in them a lucrative opportunity in the growing market for cosmetic treatments. The basic elements of autologous lipotransfer were developed more than a century ago: fatty tissue is removed by excision or suction, purified, and immediately reimplanted into the same patient (6). Over the years, the technique has seen many improvements, mostly with the goal of lessening the invasiveness of cell harvesting and processing, or else simplifying and standardizing the process of reimplantation. Conventional autologous lipotransfer now consists of aspiration lipectomy with low suction, followed by purification steps and then by cell concentration by either flotation or centrifugation; finally, the purified fatty tissue is reimplanted for soft-tissue augmentation (Figure 1). Figure 1 Conventional compared to cell-assisted autologous lipotransfer: In the former, extracorporeal processing is limited to cleansing, concentrating, and apportioning steps that precede retransplantation of the lipograft into the target tissue by injection. ... Typical applications of autologous lipotransfer include the correction of contour deficits after cancer surgery or radiotherapy; purely esthetic procedures (mainly on the breasts); and the treatment of facial atrophy due to HIV and antiretroviral drugs, systemic lupus erythematosus, or scleroderma. The limitations of this technique arise from the need for revascularization of the transplanted cells, which restricts the tissue volume that can be transplanted at once. The transplantation of an excessive volume of tissue is likely to be followed by adipocyte necrosis, volume loss, and oil cyst formation (7). Loss of transplant volume over the long term has been reported to be between 30% and 70%, even with small transplants (7, 8). Both in vitro and in vivo experiments have yielded findings suggesting a supportive effect of ADSC on the surrounding cells in autologous lipotransfer. This has prompted the development of cell-assisted lipotransfer as a putative means of improving the outcome of transplantation. The aspirated fatty tissue is divided into two aliquots, and the ADSC-containing stromal vascular fraction is then isolated from one of the aliquots and added to the other one (Figure 1). The mixture of cells generated by this process is called the cell-enriched lipoaspirate (9). Commercial systems for processing lipografts have been developed to make cell-assisted lipotransfer possible in a single operative sitting. These systems enable the rapid, automated generation of a cell-enriched lipoaspirate. Part of the aspirated fatty tissue is broken up and freed from the surrounding tissue matrix by application of a mixture of proteolytic enzymes; this tissue is then washed, and “;regenerative cells” are removed from it by centrifugation and added to the rest of the aspirated fatty tissue to make the cell-enriched lipoaspirate (10, 11). The cell-enriched lipoaspirate can be reimplanted anywhere in the body, depending on the indication. The most common indications at present are esthetic breast augmentation and breast reconstruction after tumor surgery (12). The rationale behind cell-assisted lipotransfer lies in the hope that the higher concentration of ADSCs in the cell-enriched lipoaspirate, compared to the lipoaspirate of conventional autologous lipotransfer, will enable better vascularization of the graft, thereby lessening the likelihood of necrosis and adipocyte resorption, and in the hope that the transplanted ADSC will differentiate into mature adipocytes (13). If these things happen, one should be able to transplant much larger volumes of fatty tissue at one time; in the future, one might even be able to transplant autologous fatty tissue in cases where silicon breast implants are used now. This would be a veritable revolution in reconstructive and esthetic surgery, yielding major benefits of various kinds—not least financial. There have been some encouraging findings from basic research, but hardly any clinical data on cell-assisted lipotransfer are available to date. Nor is anything known about safety issues such as the risk of inappropriate tissue differentiation or of neoplasia, an inherent danger of any stem-cell-based treatment (14, 15). The practitioners of cell-assisted lipotransfer are becoming more numerous, the advertising promoting it more intense; nonetheless, there are still no reliable figures on the frequency with which this techniques is performed (Paul Ehrlich Institute, personal communications). This state of affairs prompted us to examine the available evidence for the promising, yet controversial technique of cell-assisted lipotransfer. In accordance with the PRISMA Statement (16), we asked the following question, to be answered by application of the PICO criteria (participants, intervention, comparison, outcome): “;What evidence can be found in the current scientific literature about the clinical use of fatty tissue enriched with ADSC for the purpose of regeneration and augmentation of the soft tissues?”
Databáze: OpenAIRE
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