EVALUATION OF HOLO-TRANSCOBALAMIN AS AN INDICATOR OF VITAMIN B12 ABSORPTION

作为维生素 B12 吸收指标的全转钴胺素评估

• 批准号: 7374689
• 负责人: LYNN B BAILEY
• 金额: $ 10.63万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7374689
• 关键词: EVALUATION; HOLO; TRANSCOBALAMIN; INDICATOR; VITAMIN

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Vitamin B12 (B12) is an essential dietary nutrient required as a coenzyme for two major metabolic reactions. A deficiency of B12 may result from dietary inadequacies but more commonly results from B12 malabsorption, which may lead to anemia, irreversible neurological damage, and birth defect-affected pregnancies. Improved clinical diagnostic tests are needed to detect B12 malabsorption so that effective B12 therapy can be implemented. This study is designed to provide pilot data related to changes in a B12 transport protein, transcobalamin (TC) in response to oral B12 doses that may be used to design a new diagnostic test for B12 malabsorption. B12 binds to TC (holo-TC) rapidly after uptake by the mucosal epithelial cell, has a short half-life, and is more sensitive to changes in B12 intake and short-term status than serum B12 concentration. It is hypothesized that holo-TC concentration may be used as an indicator of B12 absorption. The primary objective of this study is to evaluate changes in holo-TC concentration in response to oral doses of B12. Healthy individuals with high-normal (serum B12 =444 pmol/L) vitamin B12 status will have blood drawn at timed intervals prior to and following three separate oral doses (9 ?g/dose) on Day 1 followed by one fasting blood sample drawn on Days 2 and 3. Holo-TC and other B12 response indices will be measured to evaluate changes in holo-TC in response to supplemental B12. The data from this pilot study will be useful in designing future studies with the long-term goal of developing new and improved diagnostic absorption tests for B12.

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。维生素B12 （B12）是一种必需的膳食营养素，作为两种主要代谢反应的辅酶。B12缺乏可能是由于饮食不足造成的，但更常见的是由于B12吸收不良，这可能导致贫血、不可逆转的神经损伤和出生缺陷影响怀孕。需要改进临床诊断测试来检测B12吸收不良，以便实施有效的B12治疗。本研究旨在提供有关B12转运蛋白，转钴胺素（TC）对口服B12剂量的反应的变化的试点数据，该数据可用于设计B12吸收不良的新诊断测试。B12被粘膜上皮细胞摄取后迅速与TC （holo-TC）结合，半衰期短，对B12摄入量和短期状态的变化比血清B12浓度更敏感。据推测，全息tc浓度可作为B12吸收的指标。本研究的主要目的是评估口服B12剂量对全息tc浓度的影响。高正常（血清B12 =444 pmol/L）维生素B12状态的健康个体将在三次单独口服剂量(9 ？g/剂量)，然后在第2天和第3天抽取空腹血样。将测量Holo-TC和其他B12反应指标，以评估补充B12后Holo-TC的变化。这项初步研究的数据将有助于设计未来的研究，长期目标是开发新的和改进的B12诊断吸收测试。