评估人体脂肪注射生存能力的裸鼠与微型计算机断层扫描
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
脂肪移植是外科医生的医疗设备为整个身体的软组织缺损治疗的一个重要工具。脂是理想的软组织填充物，因为它是现成的，容易获得的，价格低廉，并且固有生物相容的。1然而，尽管其新兴普及，脂肪移植由不可预知的结果和可变移植物存活率的阻碍，与已发表 的保留率从10不等的任何地方-80％。1-3
为了便于对脂肪移植的调查，我们已经因此开发了一种动物模型，该模型允许注入脂肪量保留的实时分析。简要地说，一个小的切口由在CD-1裸鼠的头皮和200-400微升处理的吸脂物的被放置在头骨。头皮被选择，因为其缺少天然皮下脂肪作为受体部位，并且由于由颅骨提供的优良的背景的对比度，这有助于分析过程。微型计算机断层（微CT），用于扫描所述接枝在基线和此后每两个星期。在CT图像重建和成像软件用于量化接枝卷。
传统上，技术评估脂肪移植量有必要在实施安乐死的动物研究，通过物理测量体外提供移植的重量和体积只是一个单一的评估。生化和组织学的比较也同样需要研究的动物进行安乐死。这说明成像技术提供了可视化和客观初始嫁接后多个时间点量化量的优势，而无需牺牲动物的研究。该技术是由移植物能够被注入作为更大的移植物的风险的皮肤和脂肪坏死的尺寸的限制。这种方法具有实用性的所有研究评估脂肪移植的可行性和音量保留。它特别适合于providi纳克脂肪移植的可视化表示并按照随时间的变化量。
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
直到这一点上，大多数的研究人员一直依赖于非成像方式来量化脂肪移植的长期生存，但这些方法需要在研究动物的牺牲，并产生仅一个单次测量。3,10-12我们的研究表示一种改进的分析方法，其允许在小鼠模型中的目标，实时脂肪移植存活的定量。
关键在这个过程确保充分免疫受损的小鼠用于该研究，因为这可以防止如果小鼠用完整的免疫系统被用于将发生的移植?…
Divulgations
The authors have nothing to disclose.
Acknowledgements
由ACS富兰克林H.马丁教授研究奖学金，该Hagey支持这项研究是支持的橡树基金会，Hagey实验室小儿再生医学，卫生，教育资助NIHR21DE019274，NIHR01DE019434，NIHR01DE021683国家研究所和NIHU01HL099776到MTLDCW实验室小儿再生医学，以及斯坦福大学儿童健康研究所教授学者奖。显微CT在斯坦福中心创新体内成像进行。
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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