Fernandez-Moure Joseph S, Corradetti Bruna, Chan Paige, Van Eps Jeffrey L, Janecek Trevor, Rameshwar Pranela, Weiner Bradley K, Tasciotti Ennio
Houston Methodist Hospital Department of Surgery, Houston, USA.
Department of Nanomedicine, Houston Methodist Research Institute, 6670 Bertner Avenue, Houston, TX, 77030, USA.
Stem Cell Res Ther. 2015 Oct 26;6:203. doi: 10.1186/s13287-015-0193-z.
Mesenchymal stem cells (MSCs) hold great promise for regenerative therapies in the musculoskeletal system. Although MSCs from bone marrow (BM-MSCs) and adipose tissue (AD-MSCs) have been extensively characterized, there is still debate as to the ideal source of MSCs for tissue-engineering applications in bone repair.
MSCs were isolated from cortical bone fragments (CBF-MSCs) obtained from patients undergoing laminectomy, selected by fluorescence-activated cell sorting analysis, and tested for their potential to undergo mesodermic differentiation. CBF-MSCs were then compared with BM-MSCs and AD-MSCs for their colony-forming unit capability and osteogenic potential in both normoxia and hypoxia. After 2 and 4 weeks in inducing media, differentiation was assessed qualitatively and quantitatively by the evaluation of alkaline phosphatase (ALP) expression and mineral deposition (Von Kossa staining). Transcriptional activity of osteoblastogenesis-associated genes (Alp, RUNX2, Spp1, and Bglap) was also analyzed.
The cortical fraction of the bone contains a subset of cells positive for MSC-associated markers and capable of tri-lineage differentiation. The hypoxic conditions were generally more effective in inducing osteogenesis for the three cell lines. However, at 2 and 4 weeks, greater calcium deposition and ALP expression were observed in both hypoxic and normoxic conditions in CBF-MSCs compared with AD- and BM-MSCs. These functional observations were further corroborated by gene expression analysis, which showed a significant upregulation of Bglap, Alp, and Spp1, with a 22.50 (±4.55)-, 46.56 (±7.4)-, 71.46 (±4.16)-fold increase compared with their uninduced counterparts.
This novel population of MSCs retains a greater biosynthetic activity in vitro, which was found increased in hypoxic conditions. The present study demonstrates that quantitative differences between MSCs retrieved from bone marrow, adipose, and the cortical portion of the bone with respect to their osteogenic potential exist and suggests the cortical bone as suitable candidate to use for orthopedic tissue engineering and regenerative medicine.
间充质干细胞（MSC）在肌肉骨骼系统的再生治疗中具有巨大潜力。尽管来自骨髓（BM-MSC）和脂肪组织（AD-MSC）的MSC已得到广泛表征，但对于骨修复组织工程应用中理想的MSC来源仍存在争议。
从接受椎板切除术患者的皮质骨碎片中分离出MSC（CBF-MSC），通过荧光激活细胞分选分析进行筛选，并测试其向中胚层分化的潜力。然后将CBF-MSC与BM-MSC和AD-MSC在常氧和低氧条件下的集落形成单位能力和成骨潜力进行比较。在诱导培养基中培养2周和4周后，通过评估碱性磷酸酶（ALP）表达和矿物质沉积（冯科萨染色）对分化进行定性和定量评估。还分析了成骨相关基因（Alp、RUNX2、Spp1和Bglap）的转录活性。
骨的皮质部分含有一组对MSC相关标志物呈阳性且能够进行三系分化的细胞。低氧条件通常对这三种细胞系的成骨诱导更有效。然而，在2周和4周时，与AD-MSC和BM-MSC相比，CBF-MSC在低氧和常氧条件下均观察到更大的钙沉积和ALP表达。这些功能观察结果通过基因表达分析得到进一步证实，该分析显示Bglap、Alp和Spp1显著上调，与未诱导的对应物相比分别增加了22.50（±4.55）倍、46.56（±7.4）倍、71.46（±4.16）倍。
这种新型的MSC群体在体外保留了更大的生物合成活性，在低氧条件下其活性增加。本研究表明，从骨髓、脂肪和骨皮质部分获取的MSC在成骨潜力方面存在定量差异，并表明皮质骨是用于骨科组织工程和再生医学的合适候选者。
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