Assessment of a Chitosan/Hyaluronan Injectable Composite for Fat Reconstruction

The long-term success of autologous fat transplants is dependent on numerous factors including tissue quality, tissue survivability and the expansion of the implanted cells. The addition of a biomaterial filler to an injectable gel implant matrix provides an anchor and scaffold for proliferating cells as well as a carrier for syringe delivery. Building on the tissue reconstruction concept which we first disclosed, i.e., an injectable composite comprised of beads in a gel, the present study uses an injectable composite comprised of fatty-acid-loaded chitosan/gelatin (FA-CG) beads (i.e., a degradable filler material with tissue bulking potential) and hyaluronic acid (HA, a matrix). Human and bovine preadipocytes were considered independently; however, in both cases the cells proliferated and differentiated equally when grown with the FA-CG/HA composite, as demonstrated by the production of lipids and triglycerides, as well as expression of the human adipocyte marker aP2. The preadipocyte/FA-CG/HA injectables formed stable complexes that remained intact, with little degradation and no measurable immune response, for 4 months after implantation into mice. These results suggest that FA-CG/HA composite is a suitable injectable matrix for preadipocyte transplantation, providing the basis for further studies investigating the suitability of this technique for larger-scale tissue implantation and regeneration.