Mankani M H, Kuznetsov S A, Fowler B, Kingman A, Robey P G
Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA.
Biotechnol Bioeng. 2001 Jan 5;72(1):96-107. doi: 10.1002/1097-0290(20010105)72:1<96::aid-bit13>3.0.co;2-a.
Successful closure of bone defects in patients remains an active area of basic and clinical research. A novel and promising approach is the transplantation of human bone marrow stromal cells (BMSCs), which have been shown to possess a significant osteogenic potential. The extent and quality of bone formation by transplanted human BMSCs strongly depends on the carrier matrix with which cells are transplanted; to date, hydroxyapatite/tricalcium phosphate (HA/TCP) supports far more osteogenesis than any other matrix tested. In order to further improve the technique of BMSC transplantation, we studied whether commercially available HA/TCP particles, clinically approved as an osteoconductive material and commercially available as particles measuring 0.5-1.0 mm diameter, is an optimum matrix for promoting bone development by BMSCs. HA/TCP and HA particles of varying size were sieved into a variety of size ranges, from <0.044 mm to 1.0-2.0 mm. Transplants were formed by mixing 40 mg aliquots of particles with cultured passaged human BMSCs. They were placed in subcutaneous pockets in immunocompromised Bg-Nu-XID mice and harvested 4 or 10 weeks later. The transplants were examined histologically; the presence of bone within each transplant was evaluated using histomorphometry or blindly scored on a semiquantitative scale. Transplant morphology and the amount of new bone varied in a consistent fashion based on particle size and shape. Transplants incorporating HA/TCP particles of 0.1-0.25 mm size demonstrated the greatest bone formation at both 4 and 10 weeks; larger or smaller particles were associated with less extensive bone formation, while a size of 0.044 mm represented a threshold below which no bone formation could be observed. Flat-sided HA particles measuring 0.1-0.25 mm formed no bone. The differences in bone formation were not attributable to the differences in cell attachment among the groups. Instead, the size and spatial and structural organization of the particles within BMSC transplants appear to determine the extent of bone formation. These findings provide necessary information for the successful clinical application of BMSC transplantation techniques.
在患者中成功闭合骨缺损仍是基础研究和临床研究的一个活跃领域。一种新颖且有前景的方法是移植人骨髓基质细胞（BMSC），已证明其具有显著的成骨潜能。移植的人BMSC形成骨的程度和质量在很大程度上取决于细胞移植所使用的载体基质；迄今为止，羟基磷灰石/磷酸三钙（HA/TCP）支架比任何其他测试过的基质更能支持成骨。为了进一步改进BMSC移植技术，我们研究了临床上被批准作为骨传导材料且市售的直径为0.5 - 1.0毫米颗粒的HA/TCP颗粒，是否是促进BMSC骨发育的最佳基质。将不同大小的HA/TCP和HA颗粒筛分成各种大小范围，从<0.044毫米到1.0 - 2.0毫米。通过将40毫克等分的颗粒与培养传代的人BMSC混合形成移植物。将它们置于免疫缺陷的Bg - Nu - XID小鼠的皮下袋中，并在4周或10周后收获。对移植物进行组织学检查；使用组织形态计量学评估每个移植物内骨的存在情况，或在半定量尺度上进行盲法评分。移植物的形态和新骨量根据颗粒大小和形状以一致的方式变化。在4周和10周时，包含0.1 - 0.25毫米大小HA/TCP颗粒的移植物显示出最大的骨形成；更大或更小的颗粒与较少的广泛骨形成相关，而0.044毫米的大小代表一个阈值，低于该阈值则观察不到骨形成。扁平状的0.1 - 0.25毫米HA颗粒不形成骨。骨形成的差异并非归因于各组之间细胞附着的差异。相反，BMSC移植物内颗粒的大小、空间和结构组织似乎决定了骨形成的程度。这些发现为BMSC移植技术的成功临床应用提供了必要信息。
