Changes with Aging
Changes with Aging
复制标题
随年龄增长而发生的变化
DOI：
10.1007/978-3-540-33426-2_4
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
C. Ratnatunga
中科院分区：
文献类型：
--
作者：
K. Anastasiadis;C. Ratnatunga
图2.1随年龄变化的胸腺[25]（经许可使用）在生命的第一年产生，在宿主的整个生命中存活，即使在没有胸腺的情况下，也可以维持体内的T细胞群[14]。T细胞再生通过相对低效的胸腺非依赖性途径[18]进一步复杂化了这个T细胞库的构成。这种衰老过程是性别依赖的。年龄较大的女性比年龄较大的男性更易发生胸腺迁移。然而，最近的数据显示，腺体功能充分，在优化免疫系统中发挥其作用，甚至到了60岁的时候，也有报道称，在老年人胸腺手术样本中没有完全的胸腺退化。骨髓移植后，衰老的胸腺保留了刺激naïve T细胞恢复的能力[20]。成人胸腺增生也是接受高活性抗逆转录病毒化疗[21]的hiv感染成人患者naïve T细胞恢复的原因，也是高强度化疗[14]后T细胞恢复的必要条件。然而，老年患者中T细胞存量的补充比例增加也是由于外周T细胞扩增[12,22]。如前一章所述，胸腺受整个身体神经内分泌系统的影响，包括垂体-胸腺轴。垂体与胸腺的关系随着年龄的增长而变化。胸腺发育和衰老可能受垂体生长激素的影响，而垂体受下丘脑控制。出生后下丘脑发出的最初的积极信号随着年龄的增长而减少，在青春期左右被逆转，导致胸腺萎缩[23]的发作。随着年龄的增长，胸腺功能受损可能导致老年人感染性疾病的发病率和死亡率增加，也可能是自身免疫和肿瘤所致。
Fig. 2.1 The thymus changing with age [25](Used with permission) produced in the first year of life, survives throughout the life of the host and can, even in the absence of the thymus, maintain the body’s T cell population [14]. T cell regeneration via relatively inefficient thymic-independent pathways [18] further complicate the constitution of this T cell pool. This aging process is gender-dependent. More recent thymic emigrants are found in older females than in older males [2].Recent data, however, shows that the gland functions adequately, playing its role in optimising the immune system even into the sixth decade of life [19] and there are reports of the absence of complete thymic involution in thymic surgical samples of the elderly. The aging thymus retains the ability to stimulate naïve T cell recovery after bone marrow transplantation [20]. Adult thymopoiesis is also responsible for naïve T cell recovery in HIV-infected adult patients receiving highly active antiretroviral chemotherapy [21], and is essential for recovery of T cells after intense chemotherapy [14]. An increasing proportion of repletion of the T cell stock in aged patients, however, is also due to peripheral T cell expansion [12, 22]. The thymus, as described in the previous chapter, is influenced by the whole neuroendocrine system of the body, including the pituitary-thymic axis. The relationship between the pituitary and the thymus changes with age. Thymic development and aging is probably influenced by growth hormone from the pituitary gland, which is controlled by the hypothalamus. The initially positive signals from the hypothalamus just after birth decrease with age and are reversed around puberty, leading to the onset of thymic atrophy [23]. This impaired thymic function with advancing age may contribute to the increased morbidity and mortality in the elderly from infectious diseases, and possibly from autoimmunity and neoplasia [24].
影响因子：
15.9
作者：
Flores, KG;Li, J;Hale, LP
通讯作者：
Hale, LP