Systemic rejuvenating factors and human aging phenotypes.

最近的动物研究已经确定了几种可以逆转或加速衰老的多肽或蛋白质 表型这些候选“再生因子”包括生长/分化因子11（GDF 11）， 生长/分化因子8（GDF 8），以及GDF 11和GDF 8的抑制剂：GDF 11和GDF 8前肽， 卵泡抑素、卵泡抑素相关蛋白3、WFIKKN 1和WFIKKN 2。另外两个重要的候选者是催产素 和嗜酸性粒细胞趋化因子。尽管这些循环的返老还童因子与动物衰老表型有关， 模型，一个主要的未回答的问题是这些循环蛋白或多肽是否与 人类衰老表型这些多肽或蛋白质很难在血液中进行研究 由于一些肽或蛋白质以多种同种型存在，常规的免疫测定经历后- 翻译修饰，如切割或末端降解，或与每一个具有高序列同一性。 其他.此外，循环拮抗剂可以抑制GDF 8和GDF 11的生物活性。为了 为了克服这些障碍，我们开发了一种新的多重选择反应监测分析， 色谱-串联质谱法，其测量十三种血浆蛋白质或多肽 代表了复壮研究中的八种重要蛋白质。我们将检验血浆 这些候选再生因子的浓度独立地与特定的再生因子相关并预测特定的再生因子。 老年人的衰老表型。我们的目标是对循环进行全面评估 返老还童的因素及其与人类特定衰老表型的关系。为了实现这一目标，我们 将在巴尔的摩老龄化纵向研究（BLSA）的参与者中测量这些循环因子， 生活方式干预和老年人独立性研究（LIFE）老化表型将包括流行的 和偶发性肌肉减少症、下肢体能、移动性残疾、认知、记忆、心脏 肥大、骨质疏松、胰岛素抵抗和贫血。到项目结束时，我们应该能够 验证或反驳这些候选的返老还童因子与人类衰老表型的关联。 对人类衰老表型中返老还童因子作用的验证应该会推进危险分层， 针对特定途径预防或治疗不良老化结果。

Recent animal studies have identified several polypeptides or proteins that can reverse or accelerate aging phenotypes. These candidate “rejuvenating factors” include growth/differentiation factor 11 (GDF11), growth/differentiation factor 8 (GDF8), and inhibitors of GDF11 and GDF8: GDF11 and GDF8 propeptides, follistatin, follistatin-related protein 3, WFIKKN1, and WFIKKN2. Two other important candidates are oxytocin and eotaxin. Although these circulating rejuvenating factors are associated with aging phenotypes in animal models, a major unanswered question is whether these circulating proteins or polypeptides are relevant to human aging phenotypes. These polypeptides or proteins have been difficult to study in the blood using conventional immunoassays, since some of the peptides or proteins exist in multiple isoforms, undergo post- translational modifications such as cleavage or terminal degradation, or have high sequence identity with each other. In addition, circulating antagonists can inhibit the biological activity of GDF8 and GDF11. In order to overcome these obstacles, we developed a novel multiplexed selected reaction monitoring assay using liquid chromatography-tandem mass spectrometry that measures thirteen plasma proteins or polypeptides representing eight important proteins in rejuvenation research. We will test the hypothesis that plasma concentrations of these candidate rejuvenating factors are independently associated with and predict specific aging phenotypes in older adults. Our aim is to conduct a comprehensive assessment of circulating rejuvenating factors and their relationships to specific aging phenotypes in humans. To address this aim, we will measure these circulating factors in participants of the Baltimore Longitudinal Study of Aging (BLSA) and the Lifestyle Interventions and Independence for Elders (LIFE) Study. Aging phenotypes will include prevalent and incident sarcopenia, lower extremity physical performance, mobility disability, cognition, memory, cardiac hypertrophy, osteoporosis, insulin resistance, and anemia. By the end of the project, we should be able to verify or refute the association of these candidate rejuvenating factors with phenotypes of human aging. Verification of a role for rejuvenating factors in human aging phenotypes should advance risk stratification and targeting of specific pathways in the prevention or treatment of adverse aging outcomes.