Purified viable fat suspended in matrigel improves volume longevity.

BACKGROUND: Autologous fat is an excellent soft tissue filler with cosmetic and reconstructive utility. However, graft longevity is unpredictable. OBJECTIVE: This study sought to evaluate the effect on in vivo fat graft performance of contemporary adipocyte tissue engineering techniques that have not previously been applied to mature fat cells due to the difficulty of their purification and their high metabolic demand. METHODS: Using a recently reported protocol, the adipocyte viability and purity of lipo-harvested fat were optimized. Before graft administration, these purified cells were suspended in GFR-Matrigel (BDBiosciences), a basement membrane protein matrix known to improve early angiogenesis. It was posited that by suspending the purified cells in this resorbable matrix, the high metabolic demand of these cells would be met and graft performance could be improved. The in vivo longevity of these tissue engineered fat grafts was tested in a murine model in which each subject received posterior subcutaneous injections of three types of fat graft: unpurified fat after lipo-harvest alone; fat harvested in identical fashion, but purified and suspended in GFR-Matrigel; and a control of GFR-Matrigel alone. Graft volumes and quantitative histologic characteristics were examined at 1 week, 1 month, and 3 months. RESULTS: At 3 months, purified fat/GFR Matrigel grafts showed superior fat volume maintenance (80.2% versus 29.7% for unpurified grafts [P < .05]) and adipocyte cellular longevity (70.1% versus 45.6% [P < .001). Unpurified grafts were largely replaced by fibrosis at 3 months (96.5% [95% CI 0.90-0.970]), despite starting with three times as many viable adipocytes as purified grafts. A correlation was noted between the poor performance of unpurified grafts and a disproportionate presence of early inflammation in fat grafts prepared without purification techniques. CONCLUSIONS: A preparatory regimen consisting of a preadministration purification followed by cellular suspension in a resorbable protein matrix may ultimately improve the predictability and longevity of autologous fat grafts.

Beyond the cells: scaffold matrix character affects the in vivo performance of purified adipocyte fat grafts.

BACKGROUND: Little attention has been focused on the effect of fat graft structure on in vivo performance. Having hypothesized that a stable initial graft structure was important to fat graft take-similar to the importance of shear minimization in the take of skin grafts-we have previously shown that purified adipocytes suspended in a resorbable protein matrix (GFR Matrigel; BD Biosciences, San Jose, CA) improved in vivo graft longevity. OBJECTIVE: In the present study, the importance of the matrix composition was assessed. METHODS: Age- and sex-matched genetically identical mice were implanted with fat grafts consisting of the same number of purified adult adipocytes mixed with either PuraMatrix (simple peptide hydrogel; 3DM, Cambridge, MA) or GFR Matrigel (basement membrane proteins). Control grafts composed of GFR Matrigel alone, PuraMatrix alone, or syringe-harvested (unpurified) fat alone were also injected. Volume measurements and histologic sections were taken at 1 week, 1 month, and 3 months. RESULTS: Purified fat/GFR Matrigel grafts showed statistically greater longevity and volume maintenance versus all other groups. CONCLUSIONS: Differences in matrix composition in this study were associated with profound changes in graft longevity and volume maintenance. These results suggest that cell-extracellular matrix interactions play an important role in graft survival. Future research into the nature of these interactions may provide an avenue for optimizing fat graft outcomes.

An experimental model for improving fat graft viability and purity.

BACKGROUND: Autologous fat is an excellent soft-tissue filler, given its abundance, ease of harvest, and natural appearance. However, graft longevity is unpredictable and is reported in the literature to be between 3 months and 8 years. METHODS: A genetically identical, age- and sex-matched mouse experiment was used to develop a model. Inguinal fat pads were subjected to different harvest and preparatory techniques. Primary endpoints-viability and purity-were assessed with the trypan blue viability assay and component counting with a hemocytometer. RESULTS: Viability and purity were highest after excisional harvest versus blunt or needle harvest, presumably secondary to differences in cellular trauma. Saline wash or centrifugation after harvest produced modest but statistically significant improvements in viability and purity. However, if grafts harvested in any fashion were treated with an initial collagenase digestion followed by an idealized centrifugation regimen and a single wash step, viability and purity were consistently 96 percent and 93 percent, respectively. CONCLUSIONS: Using an in vitro murine model, the authors have systematically developed a clinically practical model for creating a pure single-cell suspension of viable adipocytes that is reproducible, regardless of tissue harvest method.

Breast reconstruction.

With over 200,000 new cases of invasive breast cancer treated each year, various types of breast reconstruction have become popular and safe. Immediate breast reconstruction seems to confer both benefit and patient satisfaction. A variety of techniques including subcutaneous expanders/implants, flap transfers, and free tissue transfers are described.

Congenital melanocytic nevus and the Internet: an evaluation of available web-based resources.

The Internet has become an increasingly used tool for patient education and the coordination of support groups. For families with children diagnosed with congenital melanocytic nevus, this is also the case. To evaluate the quality of congenital melanocytic nevus-related information on the Internet, a standardized assessment of web sites was used. The overall Internet informational and support resources regarding congenital melanocytic nevus were found to be accurate and user friendly but limited. The authors recommend practitioners direct patient families to www.nevusnetwork.org as a starting point, and supplement an interest in pictures and information regarding support groups with visits to www.dermatlas.org and http://groups.MSN.com/AussieNevusSupportGroup.