Adipose tissue (AT) has become a source of mesenchymal stromal/stem cells (MSC) for regenerative medicine applications, in particular skeletal disorders. Several enzymatic or mechanical procedures have been proposed to process AT with the aim to isolate cells that can be locally implanted. How AT is processed may impact its properties. Thus, we compared AT processed by centrifugation (C-AT) to microfragmentation (MF-AT). Focusing on MF-AT, we subsequently assessed the impact of synovial fluid (SF) alone on both MF-AT and isolated AT-MSC to better understand their cartilage repair mechanisms. MF-AT and C-AT from the same donors were compared by histology and qRT-PCR immediately after isolation or as ex vivo cultures using a micro-tissue pellet system. The in vitro impact of SF on MF-AT and AT-MSC was assessed by histological staining and molecular analysis. The main AT histological features (i.e., increased extracellular matrix and cellularity) of the freshly isolated or ex vivo-cultured MF-AT persisted compared to C-AT, which rapidly deteriorated during culture. Based on our previous studies of HOX genes in MSC, we investigated the involvement of Homeobox Protein HOX-B7 (HOXB7) and its target basic Fibroblast Growth Factor (bFGF) in the molecular mechanism underlying the improved performance of MF-AT. Indeed, both these biomarkers were more prominent in freshly isolated MF-AT compared to C-AT. SF alone preserved the AT histological features of MF-AT, together with HOXB7 and bFGF expression. Increased cell performance was also observed in isolated AT-MSC after SF treatment concomitant with enhanced HOXB7 expression, although there was no apparent association with bFGF. Our findings show that MF has a positive effect on the maintenance of AT histology and may trigger the expression of trophic factors that improve tissue repair by processed AT.

中文翻译：

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微碎片脂肪组织与 HOXB7 和 b-FGF 表达相关的体外性能改善有关

脂肪组织 (AT) 已成为再生医学应用，特别是骨骼疾病的间充质基质/干细胞 (MSC) 的来源。已经提出了几种酶促或机械程序来处理 AT，目的是分离可以局部植入的细胞。AT 的处理方式可能会影响其属性。因此，我们将离心 (C-AT) 处理的 AT 与微碎 (MF-AT) 进行了比较。专注于 MF-AT，我们随后评估了滑液 (SF) 单独对 MF-AT 和孤立的 AT-MSC 的影响，以更好地了解它们的软骨修复机制。来自同一供体的 MF-AT 和 C-AT 在分离后立即通过组织学和 qRT-PCR 进行比较，或使用微组织颗粒系统作为离体培养物进行比较。通过组织学染色和分子分析评估 SF 对 MF-AT 和 AT-MSC 的体外影响。与在培养过程中迅速恶化的 C-AT 相比，新分离或离体培养的 MF-AT 的主要 AT 组织学特征（即增加的细胞外基质和细胞结构）持续存在。基于我们之前对 MSC 中 HOX 基因的研究，我们研究了同源盒蛋白 HOX-B7 (HOXB7) 及其靶标碱性成纤维细胞生长因子 (bFGF) 在改善 MF-AT 性能的分子机制中的作用。事实上，与 C-AT 相比，这两种生物标志物在新鲜分离的 MF-AT 中更为突出。SF 单独保留了 MF-AT 的 AT 组织学特征，以及 HOXB7 和 bFGF 表达。在 SF 处理后，在分离的 AT-MSC 中也观察到细胞性能增加，同时 HOXB7 表达增强，尽管与 bFGF 没有明显的关联。我们的研究结果表明，MF 对 AT 组织学的维持具有积极作用，并可能触发营养因子的表达，从而通过加工的 AT 改善组织修复。