Effect of Aging & Vitamin D Status on Osteoblastogenesis

老化的影响

• 批准号: 6951426
• 负责人: JULIANNE GLOWACKI
• 金额: $ 38.25万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-30 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6951426
• 关键词: 1,25 dihydroxycholecalciferol; aging; apoptosis; blood chemistry; bone density; bone marrow; cell differentiation; cell growth regulation; cell proliferation; clinical research; flow cytometry; high throughput technology; human old age (65+); human subject; microarray technology; northern blottings; osteoblasts; osteogenesis; osteopenia; osteoporosis; photon absorptiometry; polymerase chain reaction; single cell analysis; tissue /cell culture; vitamin D; vitamin D deficiency

DESCRIPTION (provided by applicant): This application addresses two of the goals of the RFA: Use "of in vitro methods to assay stem cell function that reflect individual differences among cell or tissue donors" and "Potential systemic effects of age-related alterations in stem and precursor cell properties in specific lineages." Skeletal aging is characterized as a gradual loss of bone mass due to an excess of bone resorption that is not balanced by new bone formation. Thus, with age, there is a gradual loss of bone measured by declining bone mineral density (BMD), to the point of osteopenia or osteoporosis, and bone fracture. Bone marrow becomes fatty and ultimately "gelatinized" with extreme age and osteoporosis. In addition, elderly people commonly have lower circulating levels of 25-dihydroxyvitamin D (25-D). Marrow stromal cells (MSCs) give rise to osteoblasts, but there is some discrepancy in the literature about the effect of age on osteoblast differentiation. We, and others, reported that there is an age-related decline in osteoblastogenesis from human bone marrow. Some others, using colony assays, report no detectable change. We have been applying an innovative automated cell tracking system developed by Dr. Greenberger for hematopoietic cells for research in skeletal aging. We have extensive experience with human marrow obtained from subjects undergoing total hip replacement for non-inflammatory joint disease. We have developed a research plan with 3 specific aims to test the hypotheses 1) that with aging there is a loss of osteoblast potential in human marrow stromal cells from men and women; 2) that vitamin D-deficiency reduces osteoblast potential, and 3) that cells from elders and vitamin D-deficient subjects can be rejuvenated in vitro by vitamin D metabolites or analogs. We will use biochemical and molecular methods to enumerate and characterize MSCs with osteoblast potential. We propose to use an innovative quantitative cell tracking system to measure differentiation as a function of age of human marrow. We will also use monolayer culture methods to assess the effects of age on progress in osteoblast differentiation. We will determine whether vitamin D metabolites or analogs promote osteoblast differentiation of marrow cells and whether the mechanisms involve increasing numbers of progenitors, changes in proliferation and apoptosis, and/or stimulation of osteoblast differentiation.

描述（由申请人提供）：本申请解决了RFA的两个目标：使用“体外方法来测定反映细胞或组织供体之间个体差异的干细胞功能”和“特定谱系中茎和前体细胞特性中与年龄相关的变化的潜在系统效应”。骨骼老化的特征是由于过量的骨吸收而导致骨骼质量的逐渐损失，而新的骨骼形成并不能平衡。因此，随着年龄的增长，通过骨矿物质密度下降（BMD），到骨质疏松症或骨质疏松症以及骨折的点，骨骼逐渐丧失。骨髓变成脂肪，最终随着极端年龄和骨质疏松症而“胶质化”。此外，老年人通常具有较低的25-二羟基维生素D（25-D）的循环水平较低。骨髓基质细胞（MSC）产生成骨细胞，但文献中有关年龄对成骨细胞分化的影响的文献差异。我们和其他人报告说，人类骨髓的成骨细胞生成与年龄有关。其他一些则使用殖民测定方法报告没有可检测的更改。我们一直在应用Greenberger博士开发的创新自动细胞跟踪系统，用于造血细胞进行骨骼老化研究。我们拥有从接受非炎症性关节疾病的总髋关节置换受试者获得的人类骨髓的丰富经验。我们制定了一个研究计划，具有3个特定旨在检验假设的特定目的1）衰老的人类骨髓基质细胞中的成骨细胞可能损失，男性和女性； 2）维生素D缺乏症可降低成骨细胞的潜力，3）可以通过维生素D代谢物或类似物在体外使来自长老和维生素D缺陷受试者的细胞在体外恢复活力。我们将使用生化和分子方法来枚举和表征具有成骨细胞潜力的MSC。我们建议使用创新的定量细胞跟踪系统来测量分化与人骨髓年龄的函数。我们还将使用单层培养方法来评估年龄对成骨细胞分化进度的影响。我们将确定维生素D代谢物或类似物是否促进了骨髓细胞的成骨细胞分化，以及该机制是否涉及增加祖细胞数量，增殖和凋亡的变化以及/或刺激骨细胞分化。