Pietrzak William S, Ali Saba N
*Department of Bioengineering, University of Illinois at Chicago, Chicago, IL †Musculoskeletal Publication and Analysis, Inc, Warsaw, IN.
J Craniofac Surg. 2017 Nov;28(8):2183-2188. doi: 10.1097/SCS.0000000000004016.
Bone morphogenetic proteins (BMPs) are associated with bone extracellular matrix and impart osteoinductive properties to demineralized bone matrix (DBM) grafts. The first step of the osteoinductive process is BMP release from DBM in situ; however, this has not been characterized for human DBM. The authors investigated the release of BMPs 2, 4, and 7 from a clinical human DBM putty (Bonus II DBM, Biomet Inc, Warsaw, IN). The DBM was placed in Sorensen buffer and the BMP concentrations in the Sorensen buffer and guanidine extracts of the DBM were measured concurrently by enzymelinked immunosorbant assay for up to 7 days. The baseline DBM concentrations were BMP-2: 28.1 ± 1.3 ng/g DBM, BMP-4: 0.577 ± 0.056 ng/g DBM, and BMP-7: 92.9 ± 7.5 ng/g DBM. Relative to baseline, the proportions released by 7 days were 11.1%, 3.9%, and 29.3%, respectively. The early (0-8 hour) and late (8-168 hours) elution rates were BMP-2: 0.16 ± 0.24 and 0.0089 ± 0.012 ng/(g DBM hr), and BMP-7: 1.29 ± 2.1 and 0.086 ± 0.039 ng/(g DBM hr), respectively. Little BMP-4 elution occurred over the first 24 hours, with the rate for the remaining interval being 0.00014 ± 0.00021 ng/(g DBM hr). The apparent DBM BMP profiles were counterintuitive in that the concentrations increased from baseline for some, or all, of the 7 days instead of monotonically decreasing. Similar behavior has previously been reported in bovine studies. This provides further evidence that BMPs are associated with at least 2 compartments in DBM differing by their affinity for BMPs and that guanidine extraction of BMPs is not 100% efficient.
骨形态发生蛋白（BMPs）与骨细胞外基质相关，并赋予脱矿骨基质（DBM）移植物骨诱导特性。骨诱导过程的第一步是BMP从DBM原位释放；然而，对于人DBM的这一特性尚未进行过描述。作者研究了临床用人DBM油灰（Bonus II DBM，Biomet公司，印第安纳州华沙）中BMP-2、BMP-4和BMP-7的释放情况。将DBM置于索伦森缓冲液中，并通过酶联免疫吸附测定法同时测量索伦森缓冲液和DBM的胍提取物中BMP的浓度，持续7天。DBM的基线浓度为：BMP-2：28.1±1.3 ng/g DBM，BMP-4：0.577±0.056 ng/g DBM，BMP-7：92.9±7.5 ng/g DBM。相对于基线，7天时释放的比例分别为11.1%、3.9%和29.3%。早期（0 - 8小时）和晚期（8 - 168小时）洗脱率分别为：BMP-2：0.16±0.24和0.0089±0.012 ng/(g DBM·小时)，BMP-7：1.29±2.1和0.086±0.039 ng/(g DBM·小时)。在最初24小时内几乎没有BMP-4洗脱，其余时间段的洗脱率为0.00014±0.00021 ng/(g DBM·小时)。DBM的BMP表观曲线与直觉相反，因为在7天中的部分或全部时间里，浓度从基线开始升高，而不是单调下降。此前在牛的研究中也报道过类似行为。这进一步证明BMP与DBM中的至少两个区室相关，这两个区室对BMP的亲和力不同，并且胍对BMP的提取效率并非100%。
