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.

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."骨骼老化的特征是由于骨吸收过多而与新骨形成不平衡而导致骨量逐渐丧失。因此，随着年龄的增长，骨矿物质密度（BMD）下降，骨质逐渐流失，直至骨质减少或骨质疏松以及骨折。随着年龄的增长和骨质疏松症，骨髓会变得脂肪并最终“糊化”。此外，老年人的 25-二羟基维生素 D (25-D) 循环水平通常较低。骨髓基质细胞（MSC）产生成骨细胞，但文献中关于年龄对成骨细胞分化的影响存在一些差异。我们和其他人报告说，人类骨髓中的成骨细胞生成随年龄的增长而下降。其他一些使用菌落分析的报告没有检测到任何变化。我们一直在应用格林伯格博士开发的创新型造血细胞自动细胞追踪系统来研究骨骼衰老。我们对从因非炎症性关节疾病接受全髋关节置换术的受试者中获得的人类骨髓拥有丰富的经验。我们制定了一项研究计划，有 3 个具体目标来检验以下假设：1）随着年龄的增长，男性和女性的人类骨髓基质细胞中的成骨细胞潜力会丧失； 2) 维生素 D 缺乏会降低成骨细胞的潜力，3) 维生素 D 代谢物或类似物可以在体外使老年人和维生素 D 缺乏受试者的细胞恢复活力。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追踪系统来测量分化作为人类骨髓年龄的函数。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、增殖和细胞凋亡的变化和/或刺激成骨细胞分化。