Telomere length analysis in the CALERIE trial

项目总结 长期卡路里限制(CR)是延长两者的最有效和最受研究的干预措施之一 从酵母到灵长类动物，各种物种的平均寿命和最长寿命。最近的证据来自 减少能量摄入长期影响的综合评估(CALERIE)建议CR 通过应用于血液化学数据的算法来衡量，延缓人类的生物衰老。这个 CR影响健康寿命的机制涉及一系列复杂的分子途径，从 减少炎症和氧化应激，改善线粒体功能，增强自噬和 增强了抗压性。值得注意的是，上述机制与端粒长度有关 监管。然而，CR是否如端粒长度所指示的那样延缓生物衰老，尚未得到解决。 以及炎症和氧化应激在假设机制中的作用。了解 CR增加健康寿命的分子途径可以为抗衰老治疗找到新的靶点。 在这里，我们将检测CALERIE患者的白细胞端粒长度(LTL)，以测试CR是否与 与随机对照相比，减少了LTL的侵蚀。低密度脂蛋白检测将使用T/S 比率和绝对qPCR检测，并根据由 端粒研究网络。此外，充分利用在整个 在试验中，我们将检查在两年的跨度中，LTL的差异何时出现(例如，更早或更晚)。 利用CALERIE生物资源库，我们将进一步测试假设的LTL是否减少了CR中的LTL侵蚀 ARM是通过降低炎症和氧化应激水平来调节的。在目标1a中，意向治疗分析将 与随机对照相比，测试CR是否与减少24个月的LTL侵蚀有关。 目标1b将进行剂量-反应分析，并调查干预效果是否由 体重减轻，并检查在24个月试验的早期或后期，对LTL变化的CR影响何时出现。 AIM 2将通过降低以下水平来测试CR是否与24个月内LTL的变化有关 12个月和24个月的炎症(因素分析包括C反应蛋白、细胞间黏附分子1、白介素1β、白介素6、白介素8、瘦素、单核细胞趋化蛋白1和肿瘤坏死因子α)， 以及12个月和24个月时氧化应激水平的降低(F2-异前列腺素-IPF(2α)-III的因子分析， 2，3-二甲基-IPF(2α)-III、IPF(2α)-VI和8，12-异IPF(2α)-VI)。这项创新的工作将从有史以来第一次 以端粒长度衡量人类热量限制是否延缓细胞衰老的随机试验设计。 这些发现将有助于在细胞水平上产生关于人类CR机制的新知识。数据 在完成检测后将与CALERIE生物库共享，供研究人员使用。

PROJECT SUMMARY Long-term caloric restriction (CR) is one of the most effective and well-studied intervention to extend both average and maximum life spans in a variety of species, from yeast to primates. Recent evidence from the Comprehensive Assessment of Long term Effects of Reducing Intake of Energy (CALERIE) suggests CR slows biological aging in humans, as measured by an algorithm applied to blood chemistry data. The mechanisms through which CR affects healthy lifespan involve a complex array of molecular pathways, from reduced inflammation and oxidative stress, improved mitochondrial function, enhanced autophagy and increased stress resistance. Notably, the aforementioned mechanisms are implicated in telomere length regulation. Yet, whether CR slows biological aging as indicated by telomere length, has not been addressed, as well as the role of inflammation and oxidative stress in the hypothesized mechanism. Understanding the molecular pathways by which CR increases healthspan could pinpoint new targets for anti-aging therapies. Here we will assay leukocyte telomere length (LTL) in CALERIE to test whether CR is associated with decreased LTL erosion as compared to the ad libitum control. LTL assays will be conducted using both the T/S ratio and the absolute qPCR assay, and communicated based on new qPCR reporting guidelines set by the Telomere Research Network. Further, making full use of the repeated measures of LTL obtained across the trial, we will examine when, during the two-year span, the differences in LTL emerge (e.g., earlier or later). Utilizing CALERIE biorepository, we will further test whether the hypothesized reduced LTL erosion in the CR arm is mediated by reduced level of inflammation and oxidative stress. In Aim 1a, intent-to-treat analysis will test whether CR is associated with reduced LTL erosion over 24 months, compared to the ad libitum control. Aim 1b will conduct dose-response analyses and investigate whether intervention effects are mediated by weight loss, and examine when, earlier or later in the 24-month trial, the CR effects on LTL change emerge. Aim 2 will test whether CR is associated with LTL changes over 24 months through reduced levels of inflammation at 12 and 24 months (factor analysis of CRP, ICAM1, IL1β, IL6, IL8, Leptin, MCP1, and TNF-α), and reduced levels of oxidative stress at 12 and 24 month (factor analysis of F2‐isoprostanes—iPF(2α)‐III, 2,3‐dinor‐iPF(2 α)‐III, iPF(2 α)‐VI, and 8,12‐iso‐iPF(2α)‐VI). This innovative work will determine from a first-ever randomized trial design if human caloric restriction slows cellular aging as measured by telomere length. Findings will help generate new knowledge about CR mechanisms in humans at the cellular level. The data generated will be shared with the CALERIE Biorepository upon completion of assays for investigators use.