Autologous Fat Graft Retention and Stem Cell Culture: A Pilot Study
Wilms, H.*, Symonds, E.^, Findlayson, C.^, Hally, K.^, Black, B.^, Sparks, S.#, Slocombe, A.#, Dennett, E.^, Danielson, K.^, Meredith, I.^,
*Capital and Coast DHB, Wellington, New Zealand
^University of Otago, Wellington, New Zealand
#Pacific Radiology, Wellington, New Zealand
Introduction: Autologous Fat Grafting (AFG) has become increasingly popular for breast reconstruction following mastectomy. The major drawback of AFG is wide variability in graft survival, with retention rates reported between 30-70% of the grafted volume. Adipose Derived Stem Cells (ADSCs), a form of mesenchymal stem cell located within the Stromal Vascular Fraction (SVF) of adipose tissue, may promote graft survival in a number of ways. ADSCs are subsequently a focus of research into enhancing survival.
Aims: The study aims are 1. To assess AFG retention via Magnetic Resonance Imaging (MRI) in a pilot cohort of women undergoing AFG. And 2. To develop methods for consistent isolation and culture of ADSCs from donor sites at the time of surgery.
Methods: 20 patients were prospectively enrolled. Of these, 5 consecutive patients (6 breasts) underwent MRI pre and post AFG. Volume change at three months was compared to the grafted volume. ADSCs were cultured from a lipoaspirate taken at surgery and characterised using Flow Cytometry. Pluripotency was confirmed by differentiating cultured ADSCs into adipocytes and osteoblasts.
Results: The mean graft retention was 73.7% at 3 months (range 30.0% to 104.7%). The abdomen was shown to have a higher yield of SVF/g of tissue than the hip, 12.4×106 versus 5.0×106 (p=0.0275). ADSC viability ranged from 29.3%-100%. Flow Cytometry confirmed successful ADSC culture. ADSCs were successfully differentiated into adipocytes and osteoblasts proving pluripotency. Patient BMI, disease state, adjuvant therapies, cell yield and viability were not found to be correlated with levels of graft retention.
Conclusions: This pilot study has demonstrated a wide range of graft retention and that it is possible to culture ADSCs in vitro which has clinical implications. Factors driving graft retention need further investigation in future research.