Sunday, October 3, 2010
18057

Progenitor Cell Mobilization Augments Fat Graft Survival

Parag Butala, MD1, Steven M. Sultan, BA1, Edward H. Davidson, MBBS1, James L. Crawford, BS1, Caroline Szpalski, MD1, Denis Knobel, MD1, Alexandre Marchac, MD1, Pierre B. Saadeh, MD2, Stephen M. Warren, MD2, Sydney R. Coleman, MD3, and Alexes Hazen, MD4. (1) Institute of Reconstructive Plastic Surgery, New York University Medical Center, 550 First Avenue, TCH-169, New York, NY 10016, (2) Institute of Reconstructive Plastic Surgery Laboratories, NYU, 560 First Avenue, TCH-169, New York, NY 10016, (3) Institute of Reconstructive Plastic Surgery, New York University Langone Medical Center, 44 Hudson Street, New York, NY 10013, (4) Institute of Reconstructive Plastic Surgery, NYU Langone Medical Center, Suite 8V, 530 First Avenue, New York, NY 10016

Introduction: Graft survival of the highest density (HD) and lowest density (LD) centrifuged lipoaspirate appears to be influenced by the quantity of functional adipocytes as well as adipose-derived stem cell concentration. We hypothesize, therefore, that mobilization of endothelial progenitor cells from the bone marrow of recipients leads to improved fat graft survival.

Methods: Male 8-week old FVB mice (n=24) underwent grafting of either 2cc of the highest density (n=12) or 2cc of the lowest density (n=12) human lipoaspirate after centrifugation using a previously established model. The mice received either AMD3100 (10mg/kg i.p. daily for 14 days) or saline. Animals were sacrificed either at 2 weeks or 10 weeks after grafting and fat was harvested for assessment of survival, and analysis by RT-PCR, ELISA, immunohistochemistry, and flow cytometry.

Results: HD grafts with saline demonstrated significantly improved 2- and 10-week graft survival compared to LD grafts (85% vs. 59%, 60% vs. 40%, p<0.05, respectively). LD grafts with AMD3100 treatment demonstrated 2- and 10-week survival comparable to HD grafts (82% vs. 75%, 52% vs. 50%, p>0.05, respectively). Quantitative RT-PCR at 2- and 10-weeks showed double the CD31 expression in low density grafts with AMD3100 (fold change 1.99 +/- 0.15). Protein quantification for VEGF at 2- and 10-weeks showed comparable amounts in treated LD compared to sham-treated HD grafts (0.42pg/ng +/- 0.04 vs. 0.38pg/ng +/- 0.09, p>0.05) while sham-treated LD grafts had significantly less VEGF compared to HD grafts (0.20pg/ng +/- 0.05 vs. 0.40pg/ng +/- 0.07, p<0.05). ELISA for stromal-derived factor-1 (SDF-1) showed similar expression patterns. These results were confirmed with immunohistochemistry for CD31; LD treated grafts demonstrated uptake comparable to HD sham-treated grafts. Isolation of lineage negative cells in harvested grafts additionally demonstrated increased concentration of progenitor cells in treated animals compared to sham-treated animals.

Conclusions: Endothelial progenitor cell supplementation of lipoaspirate improves graft survival and suggests a vasculogenic mechanism that underpins the success in microstructural fat grafting.

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