Naqvi Syeda M, Buckley Conor T
Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.
Department of Mechanical Engineering, School of Engineering, Trinity College Dublin, Dublin, Ireland.
J Anat. 2015 Dec;227(6):757-66. doi: 10.1111/joa.12305. Epub 2015 Apr 25.
Bone marrow (BM) stem cells may be an ideal source of cells for intervertebral disc (IVD) regeneration. However, the harsh biochemical microenvironment of the IVD may significantly influence the biological and metabolic vitality of injected stem cells and impair their repair potential. This study investigated the viability and production of key matrix proteins by nucleus pulposus (NP) and BM stem cells cultured in the typical biochemical microenvironment of the IVD consisting of altered oxygen and glucose concentrations. Culture-expanded NP cells and BM stem cells were encapsulated in 1.5% alginate and ionically crosslinked to form cylindrical hydrogel constructs. Hydrogel constructs were maintained under different glucose concentrations (1, 5 and 25 mM) and external oxygen concentrations (5 and 20%). Cell viability was measured using the Live/Dead® assay and the production of sulphated glycosaminoglycans (sGAG), and collagen was quantified biochemically and histologically. For BM stem cells, IVD-like micro-environmental conditions (5 mM glucose and 5% oxygen) increased the accumulation of sGAG and collagen. In contrast, low glucose conditions (1 mM glucose) combined with 5% external oxygen concentration promoted cell death, inhibiting proliferation and the accumulation of sGAG and collagen. NP-encapsulated alginate constructs were relatively insensitive to oxygen concentration or glucose condition in that they accumulated similar amounts of sGAG under all conditions. Under IVD-like microenvironmental conditions, NP cells were found to have a lower glucose consumption rate compared with BM cells and may in fact be more suitable to adapt and sustain the harsh microenvironmental conditions. Considering the highly specialised microenvironment of the central NP, these results indicate that IVD-like concentrations of low glucose and low oxygen are critical and influential for the survival and biological behaviour of stem cells. Such findings may promote and accelerate the translational research of stem cells for the treatment of IVD degeneration.
骨髓（BM）干细胞可能是用于椎间盘（IVD）再生的理想细胞来源。然而，IVD恶劣的生化微环境可能会显著影响注入干细胞的生物学和代谢活力，并损害其修复潜力。本研究调查了在由改变的氧气和葡萄糖浓度组成的IVD典型生化微环境中培养的髓核（NP）细胞和BM干细胞的活力以及关键基质蛋白的产生。将培养扩增的NP细胞和BM干细胞封装在1.5%的藻酸盐中并进行离子交联，以形成圆柱形水凝胶构建体。水凝胶构建体在不同的葡萄糖浓度（1、5和25 mM）和外部氧气浓度（5%和20%）下进行培养。使用活/死®检测法测量细胞活力，并对硫酸化糖胺聚糖（sGAG）的产生进行检测，同时通过生化和组织学方法对胶原蛋白进行定量分析。对于BM干细胞，类似IVD的微环境条件（5 mM葡萄糖和5%氧气）增加了sGAG和胶原蛋白的积累。相比之下，低葡萄糖条件（1 mM葡萄糖）与5%的外部氧气浓度相结合会促进细胞死亡，并抑制增殖以及sGAG和胶原蛋白的积累。封装NP的藻酸盐构建体对氧气浓度或葡萄糖条件相对不敏感，因为它们在所有条件下积累的sGAG量相似。在类似IVD的微环境条件下，发现NP细胞与BM细胞相比具有较低的葡萄糖消耗率，实际上可能更适合适应和维持恶劣的微环境条件。考虑到中央NP的高度特殊微环境，这些结果表明类似IVD的低葡萄糖和低氧气浓度对干细胞的存活和生物学行为至关重要且具有影响。这些发现可能会促进和加速干细胞治疗IVD退变的转化研究。
