Valutazione della solidità del grasso umano iniezione in topi nudi con Micro-Tomografia Computerizzata
Summary
Fat grafting is an essential technique for reconstructing soft tissue deficits. However, it remains an unpredictable procedure characterized by variable graft survival. Our goal was to devise a mouse model that utilizes a novel imaging method to compare volume retention between differing techniques of fat graft preparation and delivery.
Abstract
Lipotransfer è uno strumento essenziale nella armamentarium del chirurgo per il trattamento di deficit dei tessuti molli in tutto il corpo. Il grasso è il filler dei tessuti molli ideale in quanto è facilmente disponibile, facilmente ottenuto, poco costoso, e intrinsecamente biocompatibile. 1 Tuttavia, nonostante la sua popolarità crescente, innesto di grasso è ostacolato da risultati imprevedibili e la sopravvivenza del trapianto variabili, con tassi di ritenzione pubblicati che vanno da 10 -80%. 1-3
Per facilitare le indagini sulle innesto di grasso, abbiamo quindi sviluppato un modello animale che consente l'analisi in tempo reale di ritenzione del volume iniettato grasso. Brevemente, un piccolo taglio nel cuoio capelluto di un CD-1 topo nudo e 200-400 ml di lipoaspirato trasformati è disposto sopra il cranio. Il cuoio capelluto viene scelta come sito ricevente causa della sua mancanza di grasso sottocutaneo nativa, e per l'eccellente contrasto sfondo fornito dal cranica, che aiuta nellail processo di analisi. Tomografia Micro-computerizzata (micro-CT) viene utilizzato per eseguire la scansione l'innesto al basale e successivamente ogni due settimane. Le immagini TC sono ricostruite, e un software di imaging è utilizzato per quantificare i volumi di innesto.
Tradizionalmente, le tecniche per valutare il volume del trapianto di grasso hanno reso necessaria l'eutanasia dell'animale studio per fornire una sola valutazione del peso del trapianto e volume misurazione fisica ex vivo. Confronti biochimici e istologici hanno altresì richiesto l'animale studio per essere eutanasia. Questa tecnica di imaging descritta offre il vantaggio di visualizzazione e la quantificazione oggettiva volume a più punti di tempo dopo l'innesto iniziale senza dover sacrificare l'animale studio. La tecnica è limitata dalla dimensione dell'innesto grado di essere iniettato come pelle grandi innesti rischio e necrosi grassi. Questo metodo ha utility per tutti gli studi che valutano fattibilità del trapianto di grasso e la ritenzione del volume. E 'particolarmente adatto per providing una rappresentazione visiva di innesti di grasso e dopo cambiamenti di volume nel tempo.
Introduction
Soft tissue defects arise from a variety of causes including trauma, tumor resection, aging, and congenital anomaly. They can be debilitating for patients, and represent one of the most common, yet challenging problems for reconstructive surgeons. Many methods exist for addressing soft tissue deficiencies, such as local and free flaps, collagen injections, and synthetic fillers.4-8 However, since its first documented use by Neuber in 18931, autologous fat transfer remains the gold standard for the repair of soft tissue deficits, as it is ready available, easy and safe to harvest, and naturally compatible.1,2
Despite these advantages, autologous fat grafts suffer from unpredictable and variable survival, with retention rates ranging anywhere from 10-80% over time.1-3,9 In order to account for this expected loss of volume and symmetry, surgeons must often overcorrect when filling soft tissue defects, or perform multiple follow-up procedures.
Poorly vascularized graft beds are partly to blame for this tissue resorption. Additionally, the lack of a benchmark analysis method to compare graft survival may also contribute to the inconsistency in reported results. A precise method for measuring graft volume would reduce measurement error when evaluating retention rates. This in turn would help researchers more accurately identify the causative factors that affect graft survival. Although many laboratory animal models have facilitated both quantitative and qualitative assessment of human fat graft survival, most are based on histological and biochemical means and require sacrificing the study animal to yield a single measurement.3,10-12 Little has been reported on the use of imaging techniques to enumerate fat graft volume retention in vivo.
A handful of clinical studies have shown more effective measurement techniques using imaging. Magnetic Resonance Imaging (MRI) was employed by Hörl et al. to measure fat graft survival13, and CT was utilized by Har-Shai et al. and Fontdevila et al. in their analyses of volume retention after grafting in patients who suffered from HIV.14,15 Employing three-dimensional (3D) imaging software, Meier et al. measured volume retention in humans after autologous fat grafting by comparing images from the preoperative and postoperative period.16
Yet, a standardized method employing imaging to measure fat graft survival is lacking in basic science research. A high resolution imaging approach for assessing the volumes of fat grafts would allow not only for accurate and reproducible volume measurements, but also for repeated measurements allowing visualization of the evolution of fat graft survival in a real time fashion.
Protocol
Representative Results
Discussion
Fino a questo punto, la maggior parte dei ricercatori si sono basati sulle modalità non-imaging per quantificare la sopravvivenza a lungo termine degli innesti di grasso, ma questi metodi richiedono il sacrificio dell'animale studio e produrre soltanto una singola misura. 3,10-12 Il nostro studio rappresenta un metodo di analisi che consente una migliore obiettivo, in tempo reale quantificazione della sopravvivenza del trapianto di grasso in un modello murino.
Critical in que…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
Questo studio è stato sostenuto dalla Fondazione Oak, il Laboratorio Hagey Pediatrica Medicina Rigenerativa, e il National Institute of Health, Grants NIHR21DE019274, NIHR01DE019434, NIHR01DE021683, e NIHU01HL099776 di MTLDCW è stato sostenuto dalla ACS Franklin H. Martin Faculty Research Fellowship, il Hagey Laboratorio per Pediatrica Medicina Rigenerativa, e la Stanford University Child Health Research Institute Faculty Scholar Award. Micro-CT è stato condotto presso il Centro di Stanford per l'Innovazione in imaging in vivo.
Materials
| Reagents and Materials | Manufacturer |
| SAL lipoaspirate | N/A |
| Centrifuge | Beckman Coulter, Inc., Pasadena, CA |
| 50 ml conical tubes | BD Biosciences, San Jose, CA |
| CD-1 nude mice (Crl:CD1-Foxn1nu) | Charles River Laboratories, Inc., Wilmington, MA |
| Isoflurane | Henry Schein, Dublin, OH |
| 2.5% Betadine | Purdue Pharma, L.P., Stamford, CT |
| 70% Ethanol solution | Gold Shield, Hayward, CA |
| 1cc luer-lock syringe | BD Biosciences, San Jose, CA |
| 14 gauge cannula | Shippert Medical, Centennial, CO |
| Forceps | Fine Science Tools, Heidelberg, Germany |
| Tenotomy scissors | Fine Science Tools, Heidelberg, Germany |
| 6-0 nylon suture | Ethicon, Blue Ash, OH |
| Phosphate buffered saline | Gibco, Carlsbad, CA |
| micro-CT scanner | Siemens Healthcare, Pleasanton, CA |
| Phantom | TriFoil Imaging, Northridge, CA |
| Imaging analysis software | IRW, Siemens Healthcare, Pleasanton, CA |
| Scale | Mettler-Toledo International, Inc., Columbus, OH |
Riferimenti
- Gir, P., et al. Fat grafting: evidence-based review on autologous fat harvesting, processing, reinjection, and storage. Plast Reconstr Surg. 130 (1), 249-258 (2012).
- Kaufman, M. R., et al. Autologous fat transfer national consensus survey: trends in techniques for harvest, preparation, and application, and perception of short- and long-term results. Plast Reconstr Surg. 119 (1), 323-331 (2007).
- Smith, P., et al. Autologous human fat grafting: effect of harvesting and preparation techniques on adipocyte graft survival. Plast Reconstr Surg. 117 (6), 1836-1844 (2006).
- Eppley, B. L., Dadvand, B. Injectable soft-tissue fillers: clinical overview. Plast Reconstr Surg. 118 (4), 98e-106e (2006).
- Yarborough, J. M. The treatment of soft tissue defects with injectable collagen. Am J Med Sci. 290 (1), 28-31 (1985).
- Baumann, D. P., Butler, C. E. Soft tissue coverage in abdominal wall reconstruction. Surg Clin North Am. 93 (5), 1199-1209 (2013).
- Tukiainen, E. Chest wall reconstruction after oncological resections. Scand J Surg. 102 (1), 9-13 (2013).
- Zan, T., et al. Surgical treatment of facial soft-tissue deformities in postburn patients: a proposed classification based on a retrospective study. Plast Reconstr Surg. 132 (6), 1001e-1014e (2013).
- Bucky, L. P., Percec, I. The science of autologous fat grafting: views on current and future approaches to neoadipogenesis. Aesthet Surg J. 28 (3), 313-321 (2008).
- Lee, J. H., et al. The effect of pressure and shear on autologous fat grafting. Plast Reconstr Surg. 131 (5), 1125-1136 (2013).
- Kirkham, J. C., et al. The impact of liposuction cannula size on adipocyte viability. Ann Plast Surg. 69 (4), 479-481 (2012).
- Medina, M. A., et al. 3rd et al. Polymer therapy: a novel treatment to improve fat graft viability. Plast Reconstr Surg. 127 (6), 2270-2282 (2011).
- Horl, H. W., Feller, A. M., Biemer, E. Technique for liposuction fat reimplantation and long-term volume evaluation by magnetic resonance imaging. Ann Plast Surg. 26 (3), 248-258 (1991).
- Har-Shai, Y., Lindenbaum, E. S., Gamliel-Lazarovich, A., Beach, D., Hirshowitz, B. An integrated approach for increasing the survival of autologous fat grafts in the treatment of contour defects. Plast Reconstr Surg. 104 (4), 945-954 (1999).
- Fontdevila, J., et al. Assessing the long-term viability of facial fat grafts: an objective measure using computed tomography. Aesthet Surg J. 28 (4), 380-386 (2008).
- Meier, J. D., Glasgold, R. A., Glasgold, M. J. Autologous fat grafting: long-term evidence of its efficacy in midfacial rejuvenation. Arch Facial Plast Surg. 11 (1), 24-28 (2009).
- Coleman, S. R. Structural fat grafts: the ideal filler. Clin Plast Surg. 28 (1), 111-119 (2001).
- Coleman, S. R. Structural fat grafting: more than a permanent filler. Plast Reconstr Surg. 118 (3 Suppl), 108S-120S (2006).
- Pu, L. L., Coleman, S. R., Cui, X., Ferguson, R. E., Vasconez, H. C. Autologous fat grafts harvested and refined by the Coleman technique: a comparative study. Plast Reconstr Surg. 122 (3), 932-937 (2008).
- Matsumoto, D., et al. Cell-assisted lipotransfer: supportive use of human adipose-derived cells for soft tissue augmentation with lipoinjection. Tissue Eng. 12 (12), 3375-3382 (2006).
- Yoshimura, K., Suga, H., Eto, H. Adipose-derived stem/progenitor cells: roles in adipose tissue remodeling and potential use for soft tissue augmentation. Regen Med. 4 (2), 265-273 (2009).
- Zuk, P. A., et al. Multilineage cells from human adipose tissue: implications for cell-based therapies. Tissue Eng. 7 (2), 211-228 (2001).
- Habte, F., et al. Impact of a multiple mice holder on quantitation of high-throughput MicroPET imaging with and without Ct attenuation correction. Mol Imaging Biol. 15 (5), 569-575 (2013).
- Chung, M. T., et al. Micro-computed tomography evaluation of human fat grafts in nude mice. Tissue Eng Part C Methods. 19 (3), 227-232 (2013).
- Thanik, V. D., et al. A murine model for studying diffusely injected human fat. Plast Reconstr Surg. 124 (1), 74-81 (2009).
