Targeted delivery of osteoinductive molecules to biologic HA in bone grafts

将骨诱导分子靶向递送至骨移植物中的生物HA

• 批准号: 8776203
• 负责人: Jennifer L Bain
• 金额: $ 2.18万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8776203
• 关键词: Alkaline Phosphatase; Allografting; Alveolar Bone Loss; Amino Acids; BMP2 gene; Back; Binding; Biocompatible Materials; Blood Transfusion; Bone Matrix; Bone Regeneration; Bone Transplantation; Cattle; Cell Adhesion; Cell Surface Receptors; Clinical; Collagen; Congenital Disorders; Coupling; Defect; Dental; Dental Implants; Disease; Environment; Goals; Gold; Harvest; Human; Hydroxyapatites; Implant; In Vitro; Injury; Integrins; Lesion; Measures; Mesenchymal Stem Cells; Methods; Minerals; Modeling; Morbidity - disease rate; Operative Surgical Procedures; Oral cavity; Orthopedics; Osteocalcin; Osteogenesis; Outcome; Patients; Peptides; Performance; Periodontal Diseases; Phase I Clinical Trials; Procedures; Process; Proteins; Rattus; Recombinant Proteins; Recombinants; Regenerative Medicine; Relative (related person); Reporting; Research; Role; Site; Staging; Sterilization; Surface; Technology; Tooth Loss; Tooth structure; Transplanted tissue; Trauma; United States; Wit; Work; Xenograft procedure; allogenic bone transplantation; alveolar bone; aspartyl-glycyl-glutamyl-alanine; bone; bone healing; bone morphogenic protein; bone xenograft; cost; craniofacial; in vivo; mimetics; novel; osteoblast differentiation; osteoinductive factor; osteoprogenitor cell; polycaprolactone; polyglutamate; public health relevance; recombinant peptide; regenerative; response; scaffold; subcutaneous; synthetic peptide; targeted delivery; time interval

DESCRIPTION (provided by applicant): Every year in the United States, over 600,000 surgeries are performed involving bone grafts, making bone the second most common transplanted tissue, after blood transfusions (1, 2). Many of these grafts are used in dental regenerative procedures to restore alveolar bone that was lost from periodontal disease, trauma, or long-term tooth loss. Autogenous bone is widely used as the gold standard in craniofacial regenerative medicine, but comes with increased morbidity to the patient (3). Therefore clinicians often turn to allograft and xenograft materials, but these may lose osteoinductivity due to processing (4). Re-establishing the osteoinductive potential in these grafts would be a major step forward in enhancing clinical outcomes. The incorporation of osteoinductive molecules represents a promising strategy for creating a substrate that matches the performance of autografted bone. Preliminary studies from our group utilized a hydroxyapatitie (HA) binding domain that comprised of a highly negative heptaglutamate sequence (E7) that can be added to synthetic peptides and recombinant proteins to achieve an increased concentration, as well as greater retention, of these agents on HA surfaces, thus enabling sustained delivery of osteoinductive factors within sites of bone regeneration (5-7). The goal of this proposal is to utilize a specific HA binding domain to achieve targeted coupling of osteoinductive factors to biologic HA within three different commercially available dental bone graft materials: 1) acellular allograft 2) acelluar anorganic bovine xenograft and 3) allograft wit endogenous MSCs and osteoprogenitor cells. Specific Aim 1: E7-directed anchoring of osteoinductive peptides/proteins to bone grafts to increase loading and retention of osteoinductive molecules: collagen mimetic peptide (DGEA), BMP2 peptide, and rBMP2 protein will be synthesized with E7 domains and evaluated for loading and retention on three commercially available bone grafts. Specific Aim 2: Determination of osteoinductive potential of the grafts anchored with osteoinductive peptides/protein (in vitro and in vivo): In vitro: Peptides or proteins with and without E domains will be anchored to grafts. The cellular bone matrix allograft will be cultured and MSCs will be seeded onto the acellular bone grafts and also cultured. Bone formation markers such as alkaline phosphatase and osteocalcin will be measured. In vivo we will evaluate the anchored grafts ability to form bone in a subcutaneous rat model. If bone can form in this environment we speculate that in bony lesions and/or deficiencies in the oral cavity the bone forming potential should be even greater. This will set th stage for utilizing this technology in Phase I clinical trials. PUBLIC HEALTH RELEVANCE: Alveolar bone loss occurs due to a number of conditions and there is a need to regain this lost bone either for tooth retention or tooth replacement by dental implants. Autogenous bone, often considered the gold standard for regenerative procedures, requires harvesting from the patient and increased morbidity; therefore allograft bone can be used as a substitute but due to processing and sterilization procedures it may have lost important proteins that help in bone formation. By developing a method of anchoring these important proteins back to this commercially available bone we hope to increase the regenerative capacity of allograft bone comparable to the level of autogenous bone.

描述（由申请人提供）：在美国，每年进行超过 600,000 例涉及骨移植的手术，使骨成为仅次于输血的第二常见移植组织 (1, 2)。其中许多移植物用于牙齿再生手术，以恢复因牙周病、外伤或长期牙齿缺失而丢失的牙槽骨。自体骨被广泛用作颅面再生医学的金标准，但会增加患者的发病率 (3)。因此，临床医生经常转向同种异体移植和异种移植材料，但这些材料可能会因加工而失去骨诱导性 (4)。重新建立这些移植物的骨诱导潜力将是提高临床结果的重要一步。骨诱导分子的掺入代表了一种有前途的策略，用于创建与自体移植骨性能相匹配的基材。我们小组的初步研究利用了羟基磷灰石 (HA) 结合结构域，该结构域由高度负的七谷氨酸序列 (E7) 组成，可以将其添加到合成肽和重组蛋白中，以实现这些药物的浓度增加以及更大的保留。 HA 表面，从而能够在骨再生部位持续输送骨诱导因子 (5-7)。该提案的目标是利用特定的 HA 结合结构域，在三种不同的市售牙科骨移植材料中实现骨诱导因子与生物 HA 的靶向偶联：1) 无细胞同种异体移植物 2) 无细胞无机牛异种移植物和 3) 内源性 MSC 的同种异体移植物和骨祖细胞。具体目标 1：E7 定向将骨诱导肽/蛋白锚定到骨移植物上，以增加骨诱导分子的负载和保留：将使用 E7 结构域合成胶原模拟肽 (DGEA)、BMP2 肽和 rBMP2 蛋白，并评估负载和保留三种市售骨移植物。具体目标 2：确定骨诱导肽/蛋白锚定的移植物的骨诱导潜力（体外和体内）： 体外：肽 或具有和不具有E结构域的蛋白质将被锚定到移植物上。将培养细胞骨基质同种异体移植物，并将间充质干细胞接种到无细胞骨移植物上并进行培养。将测量碱性磷酸酶和骨钙素等骨形成标志物。在体内，我们将评估锚定移植物在皮下大鼠模型中形成骨的能力。如果骨可以在这种环境中形成，我们推测在口腔中的骨病变和/或缺陷中，骨形成潜力应该更大。这将为在第一阶段临床试验中利用该技术奠定基础。 公共卫生相关性：牙槽骨流失是由多种原因引起的，需要重新获得流失的骨质，以保留牙齿或通过种植牙替换牙齿。自体骨通常被认为是再生手术的黄金标准，但需要从患者身上采集骨，因此会增加发病率；因此，同种异体移植骨可以用作替代品，但由于加工和灭菌程序，它可能会失去有助于骨形成的重要蛋白质。通过开发一种将这些重要蛋白质锚定回这种市售骨骼的方法，我们希望能够提高同种异体移植骨的再生能力，使其达到与自体骨水平相当的水平。