Vurdering af virksomhedens rentabilitet for Human Fat Injektion i nøgne mus med Micro-Computed Tomography
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 afgørende redskab i kirurgens armamentarium til behandling af bløddele underskud på hele kroppen. Fedt er den ideelle blødt væv fyldstof, som det er let tilgængelige, let opnås, billig, og i sagens natur biokompatible. 1 Men på trods af sin spirende popularitet, er fedt podning hæmmet af uforudsigelige resultater og variable transplantatoverlevelse, med offentliggjorte frafald spænder overalt fra 10 -80%. 1-3
For at lette undersøgelser af fedt podning har vi derfor udviklet en dyremodel, der giver mulighed for real-time analyse af injiceret fedt volumen tilbageholdelse. Kort fortalt er et lille snit foretages i hovedbunden af en CD-1 nøgne mus og 200-400 pi af forarbejdet lipoaspirate placeres over kraniet. Hovedbunden er valgt som modtager stedet på grund af sin mangel på native subkutant fedt, og på grund af den fremragende baggrund kontrast billede af hovedskallen, som hjælper ianalyseprocessen. Micro-computertomografi (mikro-CT) anvendes til at scanne transplantatet ved baseline og hver anden uge derefter. De CT-billeder er rekonstrueret, og en billeddannende software bruges til at kvantificere graft mængder.
Traditionelt teknikker vurdere fedt graft volumen har nødvendiggjort euthanizing undersøgelsen dyr til at give bare en enkelt vurdering af graft vægt og volumen af fysisk måling ex vivo. Biokemiske og histologiske sammenligninger har ligeledes krævet undersøgelsen dyr, der skal aflives. Denne beskrevne imaging teknik har den fordel at visualisere og objektivt kvantificere volumen ved forskellige tidspunkter efter den første podning uden at ofre undersøgelsen dyr. Teknikken er begrænset af størrelsen af implantatet i stand til at blive injiceret som større transplantater risiko hud og fedt nekrose. Denne metode har nytte for alle studier, der evaluerer fedt graft levedygtighed og fastholdelse volumen. Det er især velegnet til providing en visuel repræsentation af fedt transplantater og efter ændringer i volumen 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
Indtil dette punkt har de fleste forskere påberåbt sig ikke-billeddannende modaliteter til at kvantificere den langsigtede overlevelse af fedt transplantater, men disse metoder kræver det offer af undersøgelsen af dyr og giver kun en enkelt måling. 3,10-12 Vores undersøgelse repræsenterer en forbedret analysemetode, der tillader objektiv, real-time kvantificering af fedt transplantatoverlevelse i en musemodel.
Kritisk i denne proces er at sikre, at tilstrækkeligt immunkomp…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Denne undersøgelse blev støttet af Oak Foundation, Hagey Laboratorium for Pediatric regenerativ medicin, og National Institute of Health, Grants NIHR21DE019274, NIHR01DE019434, NIHR01DE021683 og NIHU01HL099776 til MTLDCW blev støttet af ACS Franklin H. Martin Faculty Research Fellowship, den Hagey Laboratorium for Pediatric regenerativ medicin, og Stanford University Child Health Research Institute Fakultet Scholar Award. Micro-CT blev udført på 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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