Human tissue-resident stem cells combined with hyaluronic acid gel provide fibrovascular-integrated soft-tissue augmentation in a murine photoaged skin model

Background: Transplantation of adipose tissue-resident mesenchymal stem cells has been found to contribute to the establishment of a supportive fibrovascular network. The authors sought to evaluate the potential of human adipose tissue-derived stem cells to integrate with nonanimal stabilized hyaluronic acid as a novel injectable soft-tissue filler. Methods: Cell proliferation was measured by bromodeoxyuridine incorporation. Interactions of adipose tissue-derived stem cells with hyaluronic acid were documented by scanning electron microscopy. The effect of this combination on procollagen mRNA was assessed by real-time polymerase chain reaction. The potential therapeutic effects were evaluated in an athymic murine photoaged skin model by histology and by high-resolution magnetic resonance imaging. Angiogenesis was assessed by microvessel density analysis. Results: Under in vitro culture conditions, the authors found an equal proliferation capacity of adipose tissue-derived stem cells grown on hyaluronic acid versus controls. Scanning electron microscopy showed enhanced establishment of complex microvillous networks in adipose tissue-derived stem cells adherent to hyaluronic acid compared with controls. Adipose tissue-derived stem cells and hyaluronic acid induced a significant increase in procollagen 1-α-2 mRNA expression compared with controls. In an athymic murine photoaged skin model, injection of this combination ablated photoinduced skin wrinkles. Magnetic resonance imaging revealed a consistent and stable volume fill by adipose tissue-derived stem cells and nonanimal stabilized hyaluronic acid at 3 weeks. Adipose tissue-derived stem cells actively incorporated into the hyaluronic acid fill and showed an organized fibrovascular network at 3 weeks. Conclusion: The combination of adipose tissue-derived stem cells and nonanimal stabilized hyaluronic acid holds promise as a tool with which to achieve lasting volume fill in reconstructive surgical soft-tissue augmentation.