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Keren et al. NMR for human fat graft assessment

accuracy as possible, yet be readily available and graft was previously injected as a bolus, which was
provide reproducible results. A number of such not clinically applicable. Another advantage of the
models have been developed primarily with immune NMR device is its ability to measures grafted fat
deficient rodents. without the need to sacrifice the animal, allowing the
researcher to measure the fat at different time points
During the last twenty years our lab has used the during the study.
nude mouse model for human fat transplantation. [14-18]
The athymic nude mouse model was selected The advantages of this new model are the ability
because of its limited ability to reject xenografts. This to analyze small fat droplets in vivo without the
model, which has been previously used for studying necessity for manual excision of the fat. This enables
fat injection, enables the observation of the take of use of the more clinically relevant small fat droplet
human fat in an animal model without a confounding transplantation technique. This newly improved
immune response leading to graft rejection. mouse model will allow researchers and clinicians to
test new compounds for minimizing fat resorption.
In our prior work human fat was injected as a
bolus with a volume of 1 mL and a diameter of Authors’ contributions
approximately 1 cm × 1 cm. The disadvantage Data analysis and interpretation: A. Keren
of this relatively large fat bolus is necrosis of the Manuscript preparation: S. Filson
adipocytes in the center of the bolus as a result of Technical assistance: N. Smirnov-Shalom
poor revascularization. Clinicians now inject human Manuscript’s review: A. Gilhar
fat as small droplets < 0.1 mL, to maximize surface Concept design, manuscript preparation and data
area and thus vascularization. interpretation: Y. Ullmann

Indeed, many studies using the Coleman technique Financial support and sponsorship
have confirmed that small droplets of fat provide None.
better “take” than larger ones, secondary to improved
vascularization, nutrient diffusion and less ultimate Conflicts of interest
resorption. [35-37]
There are no conflicts of interest.
The main disadvantage of our previous model was the
inability to injected small droplets of human fat due Patient consent
to the difficulty of assessing the fat graft “take” using The participant gave her written informed consent.
traditional methods.
Ethics approval
Use of the NMR device demonstrated a 53% fat The study was reviewed and approved by the
resorption following the seventh week experimental Helsinki committee of the Rambam Health Care
period. This data is in accordance with the clinical Campus and the institutional review board of the
and pre-clinical data demonstrating a rate of 20-70% Technion Animal Care and Use Committee.
of fat resorption following transplantation.
REFERENCES
The accuracy of the NMR device and its suitability
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102 Plastic and Aesthetic Research ¦ Volume 4 ¦ June 27, 2017