Stress adaptation and the resilience of youth: fact or fiction?
Stress adaptation and the resilience of youth: fact or fiction?
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青少年的压力适应和恢复能力：事实还是虚构？
DOI：
10.1152/physiol.00017.2014
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Lucchesi,PamelaA
中科院分区：
文献类型：
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作者：
Rogers,LynetteK;Lucchesi,PamelaA
年轻人很有韧性！这句古老的格言指的是年轻人适应环境变化压力的能力。这些压力源的来源可以是物理（污染，营养状况，感染）或心理（创伤，养育，家庭环境）。弹性是适应不断变化的环境的能力，这种适应性压力反应（也称为变稳态）对生存至关重要。每一个有机体植物、动物、人类都发展了许多机制来适应这些压力，以确保生长、生存和繁殖。我们的适应能力是由自然（遗传倾向，表观遗传学）和养育（产前/早期生活和/或以后的生活经验）控制的。其中，遗传变异或突变是“硬连线”到我们的DNA，并不影响我们的年龄。相反，环境压力源对我们的适应能力有长期的影响，这取决于压力源的强度和他们所经历的生活阶段。这些压力被大脑感知并转化为多个组织的一系列表观遗传变化，下丘脑-垂体-肾上腺（HPA）轴的激活，以及特定脑区的结构变化。那么衰老是如何影响压力反应的呢？存在两个平行的假设。压力适应的一个常见理论是，随着年龄的增长，在年轻时起保护作用的激素和表观遗传变化（变稳态）在以后的生活中变得适应不良，因为身体和大脑的变化会随着时间的推移而积累。这种累积的非稳态负荷，无论是氧化应激，皮质类固醇还是感染因子，都会使个体无法产生额外的适应性应激反应，导致脆弱性而不是弹性（4）。这一过程的一个例子是与年龄相关的免疫功能下降，这使得老年人更容易通过适应性和先天免疫力下降而患上慢性疾病（3）。在这一理论中，青年人是有弹性的，因为他们还没有达到适应性超负荷，适应压力是有益的。
The young are resilient! This age-old adage refers to the ability of the young to adapt to changing stress in the environment. The origin of these stressors can be physical (pollution, nutrient status, infections) or psychological (trauma, parenting, home environment). Resilience is the ability to adapt to a changing environment, and this adaptive stress response (also known as allostasis) is crucial for survival. Every organism–plants, animals, humans–have developed a number of mechanisms to adapt to these stressors to ensure growth, survival, and reproduction. Our ability to adapt is controlled by both nature (genetic predisposition, epigenetics) and nurture (prenatal/early life and/or later life experiences). Of these, genetic variations or mutations are “hard-wired” into our DNA and are not affected as we age. Conversely, environmental stressors have a long-lasting effect on our ability to adapt, depending on the intensity of the stressor and the stage of life at which they are experienced. These stressors are sensed by the brain and are translated into a series of epigenetic changes in multiple tissues, activation of hypothalamic-pituitary-adrenal (HPA) axis, and structural changes in specific brain regions.How then does aging affect the stress response? Two parallel hypotheses exist. One common theory of stress adaptation is that, as we age, the hormonal and epigenetic changes that are protective in youth (allostasis) become maladaptive later in life due to alterations in the body and the brain that accumulate over time. This cumulative allostatic load, whether it is oxidative stress, corticosteroids, or infectious agents, renders the individual less able to mount an additional adaptive stress response, leading to vulnerability instead of resilience (4). An example of this process is the age-associated decrease in immune function that renders an older individual more susceptible to chronic disease through decreases in adaptive and innate immunity (3). In this theory, youth are resilient since they have not yet reached allostatic overload and the adaptation to stress is beneficial.