Fat for scars: How does adipose tissue reduce skin stiffness?

皮肤瘢痕形成可能是疾病、伤口愈合失调或放射治疗的结果。目前还没有有效的治疗疤痕（真皮纤维化），这会导致僵硬的组织，疼痛，功能丧失和毁容。最近的临床观察和经验表明，皮下注射脂肪组织能够逆转放射性诱导的真皮纤维化。为了优化这种疤痕治疗方法，需要对其如何工作的机械理解。该项目的总体目标是确定脂肪抽吸物及其组成部分能够减少和逆转真皮纤维化的病理特征的机制，以开发未来的治疗方法。将进行一系列体外实验以研究脂肪组织对肌成纤维细胞的影响，肌成纤维细胞是负责真皮中收缩和瘢痕形成的关键细胞类型。研究问题1）脂肪组织的旁分泌信号如何影响真皮肌成纤维细胞的基因表达和功能行为？从手术中收集的人脂肪组织将被加工成三种不同的脂肪组织（FAT）临床适用制剂：全脂肪抽吸物、机械破碎制剂和称为基质血管组分的酶促提取细胞群。每种脂肪都有不同的特点，虽然都被用于临床，但没有研究系统地比较它们。将在暴露于来自FAT的条件培养基后测量肌成纤维细胞存活、持久性、分化和纤维化基因表达，并将测量从每个FAT分泌的旁分泌因子。从这些数据中，我们的目标是确定脂肪组织的哪些成分是负责观察到的肌成纤维细胞的变化和负责的机制。研究问题2）脂肪如何影响细胞外基质（ECM）的产生，收缩和组织硬度？纤维化组织与过量的胶原蛋白和纤连蛋白沉积、ECM收缩和增加的组织硬度相关。我们将测量应用FAT后肌成纤维细胞的ECM组分的表达，并测量我们先前开发的三维体外真皮收缩模型中的收缩程度。我们的模型和临床瘢痕组织的组织硬度将通过动态剪切分析来测量，以收集关于FAT如何影响组织硬度的定量数据。来自这项研究的证据将允许基于证据的决定，即在给药前应如何改造脂肪组织，以及需要哪些脂肪组织成分才能获得临床益处。需要这些证据来为新的手术干预提供信息，在一个迫切未满足的临床需求的领域。许多人认为干细胞的潜力是一个高度优先的研究领域，但临床进展缓慢。该项目将临床观察带回实验室，对脂肪疗法进行逆向工程，以更好地了解脂肪组织如何改变皮肤中的疤痕组织。该项目旨在开发新的脂肪加工技术，该技术可以快速应用于临床，以工程脂肪的方式，它可以用于外科手术，以优化疤痕的治疗，并最终改善患者的预后。

Skin scarring can occur as a result of disease, dysregulated wound healing or radiotherapy. At present there is no effective treatment for scarring (dermal fibrosis), which results in stiff tissues, pain, loss of function and disfigurement. Recent clinical observations and experience demonstrated that subcutaneous injection of adipose tissue was able to reverse radio-induced dermal fibrosis. To optimise this approach for scar treatment a mechanistic understanding of how it works is required. The overall aim of this project is to determine the mechanism through which lipoaspirate, and its constituent parts, are able to reduce and reverse the pathological characteristics of dermal fibrosis, to develop future treatments. A series of in vitro experiments will be performed to investigate the effect of adipose tissue on myofibroblasts, the key cell type responsible for contraction and scar formation in the dermis. Research question 1) How do paracrine signals from adipose tissue affect the gene expression and functional behaviour of dermal myofibroblasts?Human adipose tissue collected from surgery will be processed into three different clinical applicable formulations of adipose tissue (FAT): whole lipoaspirate, a mechanically disrupted formulation and an enzymatically extracted cell population called the stromal vascular fraction. Each FAT has different characteristics and while all have been used clinically there are no studies which have systematically compared them. Myofibroblast survival, persistence, differentiation and fibrotic gene expression will be measured following exposure to conditioned media from FAT and the paracrine factors secreted from each FAT will be measured. From this data we aim to determine which components of adipose tissue are responsible for observed myofibroblast changes and the mechanisms responsible. Research question 2) How do FAT affect extracellular matrix (ECM) production, contraction and tissue stiffness?Fibrotic tissue is associated with excess collagen and fibronectin deposition, ECM contraction and increased tissue stiffness. We will measure the expression of ECM components by myofibroblasts following the application of FAT and measure the degree of contraction in our previously developed three dimensional in vitro models of dermal contraction. Tissue stiffness of our models and of clinical scar tissue will be measured through Dynamic Shear Analysis, to gather quantitative data on how FAT affects tissue stiffness.Evidence from this research will allow evidence based decisions to be made on how adipose tissue should be engineered prior to administration and which components of adipose tissue are required for clinical benefit. This evidence is needed to inform new surgical interventions, in an area where there is an urgent unmet clinical need.The potential of stem cells is recognised by many to be a high priority research area however progress to the clinic is slow. This project takes clinical observations back to the lab to reverse engineer fat therapies to better understand how adipose tissue alters scar tissues in skin. This project aims to develop novel fat processing techniques, which can be rapidly applied in the clinic to engineer fat in such a way that it can be used in surgical interventions to optimise the treatment of scars and to ultimately improve patient outcomes.