Kilpadi K L, Chang P L, Bellis S L
Department of Biomedical Engineering, University of Alabama at Birmingham, Room 904 MCLM, 1918 University Blvd., Birmingham, AL 35294, USA.
J Biomed Mater Res. 2001 Nov;57(2):258-67. doi: 10.1002/1097-4636(200111)57:2<258::aid-jbm1166>3.0.co;2-r.
The implant material hydroxylapatite (HA) has been shown in numerous studies to be highly biocompatible and to osseointegrate well with existing bone; however, the molecular mechanisms at work behind this osseointegration remain largely unexplored. One possibility is that the implant, exposed to the patient's blood during surgery, adsorbs known cell adhesive proteins such as fibronectin and vitronectin from the serum. Osteoblast precursors could then adhere to these proteins through integrin-mediated mechanisms. In the present study, we have used a quantitative ELISA assay to test the hypothesis that hydroxylapatite will adsorb more fibronectin and vitronectin from serum than two commonly used hard-tissue materials, commercially pure titanium, and 316L stainless steel. We further used the ELISA, as well as a standard cell adhesion assay, to test the hypothesis that increased protein adsorption will lead to better binding of purified integrins alpha5beta1 and alpha(v)beta3 and osteoblast precursor cells to the HA than to the metals. Our results show that fibronectin, vitronectin, alpha5beta1, alpha(v)beta3, and osteoblast precursor cells do indeed bind better to HA than to the metals, suggesting that improved integrin-mediated cell binding may be one of the mechanisms leading to better clinical bone integration with HA-coated implants.
植入材料羟基磷灰石（HA）在众多研究中已显示出具有高度生物相容性，并能与现有骨骼良好地骨结合；然而，这种骨结合背后起作用的分子机制在很大程度上仍未得到探索。一种可能性是，在手术过程中暴露于患者血液中的植入物会从血清中吸附已知的细胞粘附蛋白，如纤连蛋白和玻连蛋白。然后成骨细胞前体可以通过整合素介导的机制粘附于这些蛋白质。在本研究中，我们使用定量酶联免疫吸附测定（ELISA）来检验以下假设：与两种常用的硬组织材料，即商业纯钛和316L不锈钢相比，羟基磷灰石将从血清中吸附更多的纤连蛋白和玻连蛋白。我们还使用ELISA以及标准细胞粘附测定来检验以下假设：与金属相比，增加的蛋白质吸附将导致纯化的整合素α5β1和α(v)β3以及成骨细胞前体细胞与HA的结合更好。我们的结果表明，纤连蛋白、玻连蛋白、α5β1、α(v)β3和成骨细胞前体细胞与HA的结合确实比与金属的结合更好，这表明整合素介导的细胞结合改善可能是导致HA涂层植入物在临床上与骨结合更好的机制之一。
