Vurdering av Livskraftig of Human Fat Injeksjon i Nude Mus med Micro-Datatomografiscanning
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 er et viktig verktøy i kirurgens armamentarium for behandling av bløtvev underskudd på hele kroppen. Fett er den ideelle mykvevfyller som det er lett tilgjengelig, lett skaffes, billig, og iboende biokompatibelt. 1 Men til tross for sin voksende popularitet, er fett pode hemmet av uforutsigbare resultater og variable graft overlevelse, med publiserte oppbevaring priser som spenner alt fra 10 -80%. 1-3
For å lette undersøkelser på fett pode, har vi derfor utviklet en dyremodell som gjør det mulig for sanntids analyse av injisert fett volum oppbevaring. I korthet blir et lite kutt laget i hodebunnen til en CD-en naken mus, og 200 til 400 ul av bearbeidet lipoaspirate plasseres over skallen. Hodebunnen er valgt som mottaker området på grunn av sin manglende mors underhudsfett, og på grunn av den utmerkede bakgrunn kontrast levert av calvarium, som hjelpemidler ianalyseprosessen. Micro-computertomografi (micro-CT) brukes til å skanne pode ved baseline og deretter hver andre uke. CT-bilder er rekonstruert, og et bildebehandlingsprogrammer brukes til å kvantifisere pode volumer.
Tradisjonelt, teknikker vurdere fett pode volum har nødvendig euthanizing studien dyr å gi bare en enkelt vurdering av pode vekt og volum av fysisk måling ex vivo. Biokjemiske og histologiske sammenligninger har likeledes nødvendig studien dyr som skal avlives. Dette er beskrevet avbildningsteknikk tilbyr fordelen av å visualisere og objektivt kvantifisere volum ved flere tidspunkter etter første pode uten å måtte ofre studien dyr. Teknikken er begrenset av størrelsen av graftet i stand til å bli injisert som større grafts risiko hud og fett nekrose. Denne metoden har verktøyet for alle studier som evaluerte fett pode levedyktighet og volum oppbevaring. Den er spesielt godt egnet til providing en visuell representasjon av fett grafts og følgende endringer i volum over 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
Frem til dette punktet har de fleste forskere støttet seg på ikke-bildediagnostikk for å kvantifisere den langsiktige overlevelsen av fett grafts, men disse metodene krever offer av studien dyret og gi bare en enkelt måling. 3,10-12 Vår studie representerer en forbedret analysemetode som gjør det mulig mål, sanntids kvantifisering av fett transplantatoverlevelse i en musemodell.
Kritisk i denne prosess er å sikre at tilstrekkelig immunkompromitterte mus brukes for undersø…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Denne studien ble støttet av Oak Foundation, Hagey Laboratory for Pediatric Regenerative Medicine, og National Institute of Health, Grants NIHR21DE019274, NIHR01DE019434, NIHR01DE021683, og NIHU01HL099776 til MTLDCW ble støttet av ACS Franklin H. Martin Fakultet Stipendiat, den Hagey laboratorium for Pediatric Regenerative Medicine, og Stanford University Child Health Research Institute fakultetet Scholar Award. Mikro-CT ble utført ved 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 |
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