Bedömning av livskraft Human Fat Injektion i nakna möss med Micro-datortomografi
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 är ett viktigt verktyg i kirurgens arsenalen för behandling av mjukdels underskott på hela kroppen. Fett är den idealiska vävnadsfiller som det är lätt tillgänglig, lätt erhållas, billigt, och i sig biokompatibla. 1 Men trots sin spirande popularitet, är fett ympning hämmas av oförutsägbara resultat och rörlig transplantatöverlevnad, med publicerade avdragsprocenten varierar allt från 10 -80%. 1-3
För att underlätta utredningar av fett ympning, har vi därför utvecklat en djurmodell som möjliggör realtidsanalys av injicerat fettvolym retention. I korthet är ett litet snitt gjordes i skalpen av en CD-1 nakna möss och 200-400 pl av bearbetad lipoaspirate placeras över skallen. Hårbotten väljs som mottagare platsen på grund av dess avsaknad av infödda subkutant fett, och på grund av den utmärkta bakgrunds kontrasten tillhandahålls av calvarium, vilket underlättarprocessanalys. Micro-datortomografi (mikro-CT) används för att skanna transplantatet vid baslinjen och varannan vecka därefter. De CT-bilder rekonstrueras, och en avbildning programvara används för att kvantifiera graft volymer.
Traditionellt, till tekniker bedöma fett transplantat volym har nödvändig euthanizing studie djuret att ge bara en enda bedömning av transplantat vikt och volym genom fysisk mätning ex vivo. Biokemiska och histologiska jämförelser har likaså skyldig studien djur som skall avlivas. Detta beskrivs avbildningsteknik erbjuder fördelen av att visualisera och objektivt kvantifiera volymen vid flera tidpunkter efter initial ympning utan att behöva offra studie djuret. Tekniken begränsas av storleken av transplantatet kunna injiceras som större transplantat risk hud och fettnekros. Denna metod är användbar för alla studier som utvärderar fett transplantat livskraft och volym retention. Det är särskilt väl lämpad för att providing en visuell representation av fett transplantat och efter volymförändringar över tid.
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
Fram till denna punkt har de flesta forskare förlitat sig på icke-avbildningsmetoder för att kvantifiera den långsiktiga överlevnaden av fett transplantat, men dessa metoder kräver offret av studie djuret och ger endast en enda mätning. 3,10-12 Vår studie representerar en förbättrad analysmetod som möjliggör objektiv, realtids kvantifiering av fett transplantatöverlevnad i en musmodell.
Kritiskt i denna process är att säkerställa att tillräckligt immunsupprimerade…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
Denna studie stöddes av Oak Foundation, Hagey Laboratoriet för Pediatric regenerativ medicin, och National Institute of Health, Grants NIHR21DE019274, NIHR01DE019434, NIHR01DE021683 och NIHU01HL099776 till MTLDCW stöddes av ACS Franklin H. Martin fakulteten Research Fellowship, den Hagey Laboratoriet för Pediatric regenerativ medicin, och Stanford University Child Health Research Institute fakulteten Scholar Award. Micro-CT utfördes vid Stanford Center for Innovation i in vivo Imaging.
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
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