Gothard David, Smith Emma L, Kanczler Janos M, Black Cameron R, Wells Julia A, Roberts Carol A, White Lisa J, Qutachi Omar, Peto Heather, Rashidi Hassan, Rojo Luis, Stevens Molly M, El Haj Alicia J, Rose Felicity R A J, Shakesheff Kevin M, Oreffo Richard O C
Bone and Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton, SO16 6YD, United Kingdom.
Wolfson Centre for Stem Cells, Tissue Engineering and Modelling, School of Pharmacy, University of Nottingham, Centre for Biomolecular Sciences, University Park, Nottingham, NG7 2RD, United Kingdom.
PLoS One. 2015 Dec 16;10(12):e0145080. doi: 10.1371/journal.pone.0145080. eCollection 2015.
The current study has investigated the use of decellularised, demineralised bone extracellular matrix (ECM) hydrogel constructs for in vivo tissue mineralisation and bone formation. Stro-1-enriched human bone marrow stromal cells were incorporated together with select growth factors including VEGF, TGF-β3, BMP-2, PTHrP and VitD3, to augment bone formation, and mixed with alginate for structural support. Growth factors were delivered through fast (non-osteogenic factors) and slow (osteogenic factors) release PLGA microparticles. Constructs of 5 mm length were implanted in vivo for 28 days within mice. Dense tissue assessed by micro-CT correlated with histologically assessed mineralised bone formation in all constructs. Exogenous growth factor addition did not enhance bone formation further compared to alginate/bone ECM (ALG/ECM) hydrogels alone. UV irradiation reduced bone formation through degradation of intrinsic growth factors within the bone ECM component and possibly also ECM cross-linking. BMP-2 and VitD3 rescued osteogenic induction. ALG/ECM hydrogels appeared highly osteoinductive and delivery of angiogenic or chondrogenic growth factors led to altered bone formation. All constructs demonstrated extensive host tissue invasion and vascularisation aiding integration and implant longevity. The proposed hydrogel system functioned without the need for growth factor incorporation or an exogenous inducible cell source. Optimal growth factor concentrations and spatiotemporal release profiles require further assessment, as the bone ECM component may suffer batch variability between donor materials. In summary, ALG/ECM hydrogels provide a versatile biomaterial scaffold for utilisation within regenerative medicine which may be tailored, ultimately, to form the tissue of choice through incorporation of select growth factors.
本研究调查了去细胞、脱矿化的骨细胞外基质（ECM）水凝胶构建体在体内组织矿化和骨形成中的应用。将富含Stro-1的人骨髓基质细胞与包括血管内皮生长因子（VEGF）、转化生长因子-β3（TGF-β3）、骨形态发生蛋白-2（BMP-2）、甲状旁腺激素相关蛋白（PTHrP）和维生素D3（VitD3）在内的特定生长因子结合，以促进骨形成，并与藻酸盐混合以提供结构支撑。生长因子通过快速（非成骨因子）和缓慢（成骨因子）释放的聚乳酸-羟基乙酸共聚物（PLGA）微粒进行递送。将长度为5毫米的构建体植入小鼠体内28天。通过微型计算机断层扫描（micro-CT）评估的致密组织与所有构建体中组织学评估的矿化骨形成相关。与单独的藻酸盐/骨ECM（ALG/ECM）水凝胶相比，添加外源性生长因子并未进一步增强骨形成。紫外线照射通过降解骨ECM成分中的内源性生长因子以及可能的ECM交联来减少骨形成。BMP-2和VitD3挽救了成骨诱导作用。ALG/ECM水凝胶表现出高度的骨诱导性，血管生成或软骨生成生长因子的递送导致骨形成改变。所有构建体均表现出广泛的宿主组织侵入和血管化，有助于整合和植入物的长期存活。所提出的水凝胶系统无需结合生长因子或外源性诱导细胞源即可发挥作用。由于骨ECM成分在供体材料之间可能存在批次差异，因此需要进一步评估最佳生长因子浓度和时空释放曲线。总之，ALG/ECM水凝胶为再生医学提供了一种通用的生物材料支架，最终可通过结合特定生长因子来定制，以形成所需的组织。
