Effect of Aging & Vitamin D Status on Osteoblastogenesis

老化的影响

• 批准号: 6848136
• 负责人: JULIANNE GLOWACKI
• 金额: $ 36.78万
• 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/6848136
• 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）：本申请涉及RFA的两个目标：使用“体外方法测定反映细胞或组织供体个体差异的干细胞功能”和“特定谱系中干细胞和前体细胞特性年龄相关改变的潜在全身效应”。“骨老化的特征是由于过量的骨吸收而导致的骨量逐渐丢失，而新骨的形成并不平衡。因此，随着年龄的增长，通过降低骨矿物质密度（BMD）来测量骨的逐渐损失，达到骨质减少或骨质疏松症和骨折的程度。随着年龄的增长和骨质疏松症，骨髓变得脂肪化并最终“凝胶化”。此外，老年人通常具有较低的25-二羟维生素D（25-D）循环水平。骨髓基质细胞（MSCs）可以分化为成骨细胞，但关于年龄对成骨细胞分化的影响，文献中存在一些分歧。我们和其他人报道了人骨髓中成骨细胞的生成与年龄有关。其他一些人，使用菌落测定，报告没有检测到变化。我们一直在应用由Greenberger博士开发的用于造血细胞的创新自动细胞跟踪系统，用于骨骼衰老的研究。我们对从因非炎性关节疾病接受全髋关节置换术的受试者中获得的人骨髓有丰富的经验。我们已经制定了一项研究计划，有3个具体目标，以测试假设1）随着年龄的增长，男性和女性的人骨髓基质细胞中的成骨细胞潜能丧失; 2）维生素D缺乏降低成骨细胞潜能，3）老年人和维生素D缺乏受试者的细胞可以通过维生素D代谢物或类似物在体外恢复活力。我们将使用生物化学和分子生物学方法来计数和表征具有成骨细胞潜能的MSC。我们建议使用一种创新的定量细胞跟踪系统来测量分化作为年龄的函数的人骨髓。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展的影响。我们将确定维生素D代谢物或类似物是否促进骨髓细胞的成骨细胞分化，以及其机制是否涉及祖细胞数量的增加、增殖和凋亡的变化和/或成骨细胞分化的刺激。