Impact of TPO Treatment on Bone Healing and Angiogenesis in Type 2 Diabetes

TPO 治疗对 2 型糖尿病骨愈合和血管生成的影响

• 批准号: 9492356
• 负责人: Melissa A Kacena
• 金额: --
• 依托单位: RLR VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9492356
• 关键词: Adjuvant; Adverse effects; Affect; American; Angiogenic Factor; Autologous Transplantation; Binding; Biological; Biomechanics; Blood Cells; Blood Circulation; Blood Platelets; Blood Vessels; Blood capillaries; Bone Morphogenetic Proteins; Bone Regeneration; Bone Resorption; Bone Transplantation; Bone callus; Caring; Cell physiology; Cells; Chronic; Comprehensive Health Care; Data; Day Care; Defect; Diabetes Mellitus; Diabetic mouse; Diet; Disease; Endothelial Cells; Equilibrium; FDA approved; Family suidae; Fat-Restricted Diet; Femur; Fracture; Fracture Healing; Frequencies; Functional disorder; Generations; Glucose Intolerance; Goals; Gold; Growth Factor; Harvest; Healthcare Systems; Hematological Disease; Hematopoietic; High Fat Diet; Hip region structure; Histologic; Hyperglycemia; Hyperinsulinism; Impairment; In Vitro; Individual; Intervention; Knock-out; Link; Literature; MPL gene; Malignant Neoplasms; Measures; Mediating; Megakaryocytes; Mesenchymal; Microcirculation; Minerals; Mus; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Operative Surgical Procedures; Orthopedics; Osteoblasts; Osteoclasts; Osteogenesis; Outcome; Overweight; Pain; Pathway interactions; Patients; Performance; Persons; Pharmacy facility; Physiological; Platelet Count measurement; Population; Property; Rattus; Regulatory Pathway; Research Personnel; Risk; Risk Factors; Role; Safety; Saline; Series; Site; Source; Surgeon; Techniques; Testing; Therapeutic Effect; Thrombopoietin; Time; Torque; Torsion; Treatment Efficacy; Veterans; Work; Wound Healing; angiogenesis; base; bone; bone healing; bone morphogenetic protein 2; cost; diabetes control; diabetic; diabetic patient; experimental group; healing; hospital bed; improved; microCT; mimetics; mouse model; non-diabetic; novel therapeutics; regenerative; scaffold; statistics; vasculogenesis

Currently, 1 in 4 veterans receiving VA care is diabetic, and over 70% are overweight or obese and at risk of developing diabetes. Diabetes is a risk factor for impaired fracture healing and numerous studies have demonstrated increased frequency of non-union, partial union, or delayed union in diabetic patients as compared to non-diabetic patients. Diabetic patients have impaired microcirculation which is partially responsible for these fracture complications. In the case of non-union, additional interventions are required such as bone grafting techniques. The gold standard for grafting to achieve bone union is the use of autograft from the patient's hip, which may not always achieve healing. Additionally, the harvest of bone often leaves patients with a painful donor site that may not resolve. Therefore, orthopaedic surgeons desire a biologic enhancement for bone healing that does not require the harvesting of iliac crest bone. Local placement of bone morphogenetic proteins (BMPs) is the only FDA approved biological option capable of healing non-unions. BMPs, although potent in promoting bone regeneration, have been associated with several side effects, including a link with cancer. Therefore, there is a great need for new therapies that heal bone with improved safety profiles. Recently, we found that thrombopoietin [TPO, a megakaryocyte (MK) growth factor] could heal critical-sized bone defects in mice, rats and pigs, as well as, if not better than, BMP-2. The long-term goal of this work is to determine whether thrombopoietic agents could serve as novel therapies for bone healing. Our studies as well as the literature show that TPO increases pathways associated with angiogenesis, increases hematopoietic cell populations, including osteoclasts (OCs) and MKs, and increases osteoblasts (OBs) and bone formation, the latter is indirectly through MK-mediated OB proliferation. Based on these ideas, we hypothesize that TPO accelerates bone healing in type 2 diabetes (T2D) by stimulating angiogenesis which has the direct benefit of delivering mesenchymal and hematopoietic cells that mediate wound healing. In Aim 1, we will assess the therapeutic effects of TPO on bone healing in diet-induced obesity with hyperglycemia, hyperinsulinemia, and glucose intolerance (T2D). Mice on a C57BL/6 background will be fed a low fat diet (LFD) or a high fat diet (HFD), will undergo a segmental bone defect surgery, will be treated with saline (negative control), BMP-2 (positive control), or TPO (experimental group), and bone healing assessed. In Aim 2, we will demonstrate the role of TPO in stimulating angiogenesis/vasculogenesis. This will be accomplished by characterizing angiogenesis/vasculogenesis in mice from Aim 1, as well as in mice in which the TPO receptor has been selectively knocked out of endothelial cells (ECs). We will also conduct a series of in vitro studies to assess the impact of TPO treatment as well as secreted factors from MKs on EC function to begin dissecting the mechanisms responsible. Successful accomplishment of these Aims will demonstrate the utility of using TPO for improving bone healing in diabetic patients. This project has high translational potential as thrombopoietic agents are currently FDA approved for treatment of low platelet numbers. Therefore, the regulatory pathway for obtaining FDA approval for a new indication, fracture healing, is easier than it would be for a compound or biologic which has never been used in patients. Finally, demonstrating the mechanism by which TPO stimulates angiogenesis will be important for determining whether other downstream targets should also be evaluated for therapeutic efficacy.

目前，接受退伍军人管理局护理的退伍军人中有四分之一患有糖尿病，超过 70% 的人超重或肥胖，并且患有糖尿病。 患糖尿病的风险。糖尿病是骨折愈合受损的危险因素，大量研究表明 表明糖尿病患者不愈合、部分愈合或延迟愈合的频率增加 与非糖尿病患者相比。糖尿病患者的微循环受损，部分 造成这些骨折并发症的原因。在不结合的情况下，需要额外的干预措施 比如骨移植技术。 实现骨愈合的移植的黄金标准是使用患者髋部的自体移植物，这 可能并不总是能达到治愈的目的。此外，骨头的采集常常会给患者带来痛苦的捐赠者 可能无法解决的网站。因此，骨科医生希望通过生物手段促进骨愈合 不需要采集髂嵴骨。骨形态发生蛋白的局部放置 (BMP) 是 FDA 批准的唯一能够治愈骨不连的生物选择。 BMP 虽然在以下方面很有效： 促进骨再生，与多种副作用有关，包括与癌症的联系。 因此，非常需要能够以更高的安全性来治愈骨骼的新疗法。最近，我们 发现血小板生成素 [TPO，一种巨核细胞 (MK) 生长因子] 可以治愈严重大小的骨缺损 小鼠、大鼠和猪，以及 BMP-2（如果不是更好的话）。这项工作的长期目标是确定 血小板生成剂是否可以作为骨愈合的新疗法。 我们的研究和文献表明 TPO 增加与血管生成相关的途径， 增加造血细胞群，包括破骨细胞 (OC) 和 MK，并增加成骨细胞 (OB) 和骨形成，后者是通过 MK 介导的 OB 增殖间接实现的。基于这些想法， 我们假设 TPO 通过刺激血管生成来加速 2 型糖尿病 (T2D) 的骨愈合 它的直接好处是输送介导伤口愈合的间充质和造血细胞。 在目标 1 中，我们将评估 TPO 对饮食引起的肥胖症骨愈合的治疗效果 高血糖、高胰岛素血症和葡萄糖不耐受（T2D）。 C57BL/6 背景上的小鼠将被喂食 低脂饮食（LFD）或高脂饮食（HFD），将接受节段性骨缺损手术，将接受以下治疗 生理盐水（阴性对照）、BMP-2（阳性对照）或 TPO（实验组），并评估骨愈合。 在目标 2 中，我们将展示 TPO 在刺激血管生成中的作用。这将是 通过表征来自目标 1 的小鼠以及其中的小鼠的血管生成/血管发生来完成 TPO 受体已被选择性地从内皮细胞 (EC) 中敲除。我们还将开展一系列 体外研究评估 TPO 治疗以及 MK 分泌因子对 EC 功能的影响 开始剖析负责的机制。 这些目标的成功实现将证明使用 TPO 改善骨骼的效用 糖尿病患者的康复。该项目具有很高的转化潜力，因为血小板生成剂目前正在 FDA 批准用于治疗低血小板数量。因此，获得FDA的监管途径 批准骨折愈合这一新适应症比批准一种化合物或生物制剂更容易。 从未用于患者。最后，证明 TPO 刺激血管生成的机制将 对于确定其他下游靶点是否也应该进行治疗评估很重要 功效。