Abstract: Micro-CT Evaluation of Human Fat Grafts Enriched with Adipose-Derived Stromal Cells in Nude Mice (Plastic Surgery 2012)

Saturday, October 27, 2012: 1:55 PM

Michael Thomas Chung, BS , Plastic and Reconstructive Surgery, Stanford University, Stanford, CA

Jeong S. Hyun, MD , Plastic and Reconstructive Surgery, Stanford University, Stanford, CA

David D. Lo, MD , Plastic and Reconstructive Surgery, Stanford University, Stanford, CA

Daniel T. Montoro, BS , Hagey Laboratory for Regenerative Medicine/Plastic Surgery, Stanford Univeristy, Stanford, CA

Masakazu Hasegawa, MD , Hagey Laboratory for Regenerative Medicine/Plastic Surgery, Stanford Univeristy, Stanford, CA

Allison C. Nauta, MD , Plastic and Reconstructive Surgery, Stanford University, Stanford, CA

Michael T Longaker, MD, MBA , Hagey Laboratory for Regenerative Medicine/Plastic Surgery, Stanford Univeristy, Stanford, CA

Derrick C. Wan, MD , Hagey Laboratory for Regenerative Medicine/Plastic Surgery, Stanford Univeristy, Stanford, CA

Presentation PDF file

Background: Although autologous fat grafting has revolutionized the field of soft tissue reconstruction and augmentation, long-term maintenance of fat grafts is unpredictable. Recent studies have reported resorption rates of fat grafts to vary anywhere between 20-90% over time. The present study evaluated the long-term viability of human fat grafts in a murine model using a novel imaging technique allowing for in vivo volumetric analysis.

Methods: Human fat grafts were prepared from lipoaspirate samples using the Coleman technique. Fat was injected subcutaneously into the scalp of eight adult Crl:NU-Foxn1^nu CD-1 male mice. Micro-CT was performed immediately following injection and then weekly. Fat volume was rendered by reconstructing a 3D surface through cubic-spline interpolation. Specimens were also harvested at various time points and sections were prepared and stained with hematoxylin and eosin (H&E) and cannabinoid receptor 1 (CB1). Samples were also explanted at 8- and 12-week time points to validate calculated micro-CT volumes.

Results: Weekly CT scanning demonstrated progressive volume loss over the time course. However, volumetric analysis at the 8-and 12-week time points stabilized, showing an average of 62.2% and 62.7% persistence, respectively. Gross analysis showed the fat graft to be healthy and vascularized. H&E analysis showed minimal inflammatory reaction with viable adipocytes. Immunohistochemical staining with anti-human CB1 antibodies confirmed the human origin of the adipocytes.

Conclusions: Studies assessing the fate of autologous fat grafts in animals have focused on non-imaging modalities, including histological and biochemical analyses, which require euthanasia of the animals. In this study, we have demonstrated the ability to employ micro-CT for 3D reconstruction and volumetric analysis of human fat grafts in a mouse model. Importantly, this model provides a platform for subsequent study of fat manipulation and viability as well as soft tissue engineering with adipose-derived stromal cells.

20451 Micro-CT Evaluation of Human Fat Grafts Enriched with Adipose-Derived Stromal Cells in Nude Mice