Szpalski Caroline, Nguyen Phuong D, Cretiu Vasiliu Cornelia E, Chesnoiu-Matei Ioana, Ricci John L, Clark Elizabeth, Smay James E, Warren Stephen M
Department of Plastic Surgery, New York University Langone Medical Center, New York, NY, USA.
J Craniofac Surg. 2012 May;23(3):638-44. doi: 10.1097/SCS.0b013e31824db8d4.
Microporous scaffolds designed to improve bony repair have had limited success; therefore, we sought to evaluate whether time-released porous scaffolds with or without recombinant bone morphogenetic protein 2 (rhBMP-2) could enhance stem cell osteoinduction. Custom-made 15/85 hydroxyapatite/β-tricalcium phosphate scaffolds were left empty (E) or filled with rhBMP-2 (E+), calcium sulfate (CS), or CS and rhBMP-2 (CS+). All scaffolds were placed in media and weighed daily. Conditioned supernatant was analyzed for rhBMP-2 and then used to feed human adipose-derived mesenchymal stem cells (ASCs). Adipose-derived mesenchymal stem cell ALP activity, OSTERIX expression, and bone nodule formation were determined. E scaffolds retained 97% (SD, 2%) of the initial weight, whereas CS scaffolds had a near-linear 30% (SD, 3%) decrease over 60 days. E+ scaffolds released 155 (SD, 5) ng of rhBMP-2 (77%) by day 2. In contrast, CS+ scaffolds released only 30 (SD, 2) ng (10%) by day 2, and the remaining rhBMP-2 was released over 20 days. Conditioned media from E+ scaffolds stimulated the highest ALP activity and OSTERIX expression in ACSs on day 2. However, after day 6, media from CS+ scaffolds stimulated the highest ALP activity and OSTERIX expression in ASCs. Adipose-derived mesenchymal stem cells exposed to day 8 CS+-conditioned media produced significantly more bone nodules (10.1 [SD, 1.7] nodules per high-power field) than all other scaffolds. Interestingly, day 8 conditioned media from CS scaffolds simulated significantly more bone nodules than either E or E+ scaffold (P < 0.05 for both). Time-released hydroxyapatite/β-tricalcium phosphate porosity provides sustained growth factor release, enhances ASC osteoinduction, and may result in better in vivo bone formation.
旨在改善骨修复的微孔支架效果有限；因此，我们试图评估含或不含重组骨形态发生蛋白2（rhBMP-2）的缓释多孔支架是否能增强干细胞的骨诱导作用。定制的15/85羟基磷灰石/β-磷酸三钙支架保持为空（E组），或填充rhBMP-2（E+组）、硫酸钙（CS组），或CS与rhBMP-2（CS+组）。所有支架均置于培养基中，每天称重。分析条件培养基中的rhBMP-2，然后用于培养人脂肪来源的间充质干细胞（ASC）。测定脂肪来源间充质干细胞的碱性磷酸酶（ALP）活性、osterix表达和骨结节形成情况。E组支架在60天内保持了初始重量的97%（标准差，2%），而CS组支架在60天内重量近乎呈线性下降了30%（标准差，3%）。E+组支架在第2天时释放了155（标准差，5）ng的rhBMP-2（77%）。相比之下，CS+组支架在第2天时仅释放了30（标准差，2）ng（10%），其余的rhBMP-2在20天内释放。E+组支架的条件培养基在第2天时刺激ASC产生了最高的ALP活性和osterix表达。然而，在第6天后，CS+组支架的培养基刺激ASC产生了最高的ALP活性和osterix表达。暴露于第8天CS+组条件培养基的脂肪来源间充质干细胞产生的骨结节明显多于所有其他支架（每高倍视野10.1[标准差，1.7]个结节）。有趣的是，CS组第8天的条件培养基模拟产生的骨结节明显多于E组或E+组支架（两者P<0.05）。缓释羟基磷灰石/β-磷酸三钙孔隙率能实现生长因子的持续释放，增强ASC的骨诱导作用，并可能在体内带来更好的骨形成效果。
