Subcutaneous fat tissue engineering using autologous adipose-derived stem cells seeded onto a collagen scaffold

Background: This pilot study examined the efficacy of 5-bromo-2- deoxyuridine-labeled autologous adipose-derived stem cells seeded onto collagen scaffolds to augment and/or regenerate the fat-enriched hypodermal tissue in an acute porcine wound model. Methods: Porcine autologous adipose-derived stem cells were isolated and cultured. At passage 2, the cells were labeled with 5-bromo-2-deoxyuridine, seeded onto a three-dimensional collagen scaffold, and cultured for 10 days. Scaffolds were implanted subcutaneously in adult pigs with two adipose-derived stem cell scaffolds and two control scaffolds. Animals were euthanized at 2, 4, 8, and 12 weeks; all scaffold conditions were explanted for histology and immunohistochemistry analyses. Results: For all time points, adipose-derived stem cell scaffolds had increased connective tissue matrix within the subcutaneous tissue compared with scaffold alone and untreated porcine skin (p < 0.01). The neosynthesized connective tissue was vascularized and composed of small cells within an abundant extracellular matrix organized in layers. 5-Bromo-2-deoxyuridine cells were detectable only up to 4 weeks and mature adipocytes were absent. Levels of collagen types I, III, and VI differed among the experimental groups, with increased extracellular matrix associated with the presence of adipose-derived stem cells. Conclusions: The authors data clearly show the efficacy of adipose-derived stem cells for soft-tissue repair and skin aging because it induces a significant increase of the dermis thickness. Moreover, the authors results demonstrate the interest of their acute wound model and allowed them to show the skin thickness variation over time of the experiment, which is one of the challenges with which clinicians struggle in fat grafting.