Asthma is a common lung condition that makes breathing difficult through the inflammation and constriction of the lung airways. Epidemiological evidence supports the presence of a positive association between prenatal maternal psychological stress (PMPS) and asthma in the offspring, suggesting the disease may have developmental origins. T‐helper 2 (Th2) cells are a major subtype of T‐helper cells, producing Th2 cytokines, which may be the main drivers of asthma symptoms. A Th2 dominant blood cytokine profile may therefore indicate an increased risk of asthma, as studies have shown a link between PMPS and a T‐helper 2 (Th2) cytokine profile in offspring. The mechanism by which PMPS may cause Th2 cytokine dominance in the offspring is unclear. Epigenetic modifications in utero can lead to long‐lasting effects that persist postnatally and have therefore been implicated in this relationship. Increased maternal blood cortisol levels due to PMPS may increase transfer of cortisol to the foetus, where the temporarily increased levels may induce changes in the epigenome. Evidence from animal studies suggests that genes controlling cytokine production in T cells can be epigenetically modified in a way that increases Th2 cytokine production. Other evidence suggests that methylation of the NR3C1 gene decreases hippocampal glucocorticoid receptor expression, leading to decreased negative regulation of the hypothalamus‐pituitary‐adrenal axis. This can increase cortisol production which has been shown to increase Th2 cytokine production. Therefore, the link between PMPS and a Th2 offspring cytokine profile, mediated through epigenetic changes, may explain the positive relationship between PMPS and asthma in the offspring.

中文翻译：

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孕期母亲心理压力对后代患哮喘风险的影响。

哮喘是一种常见的肺部疾病，会通过肺气道的炎症和收缩而使呼吸困难。流行病学证据支持在后代中产前产妇心理压力（PMPS）与哮喘之间存在正相关，这表明该疾病可能起源于发育。T辅助细胞2（Th2）细胞是T辅助细胞的主要亚型，产生Th2细胞因子，可能是哮喘症状的主要驱动因素。因此，Th2占优势的血液细胞因子谱可能表明患哮喘的风险增加，因为研究表明后代中PMPS与T-helper 2（Th2）细胞因子谱之间存在联系。PMPS可能在后代中引起Th2细胞因子优势的机制尚不清楚。子宫内的表观遗传修饰可导致长期影响，这种影响在出生后持续存在，因此与这种关系有关。由PMPS引起的孕妇血液皮质醇水平升高可能会增加皮质醇向胎儿的转移，而暂时升高的水平可能会导致表观基因组发生变化。来自动物研究的证据表明，可以以增加Th2细胞因子产生的方式在表观遗传学上修饰控制T细胞中细胞因子产生的基因。其他证据表明，NR3C1基因的甲基化可降低海马糖皮质激素受体的表达，从而降低下丘脑-垂体-肾上腺轴的负调控。这可以增加皮质醇的产生，已显示增加了Th2细胞因子的产生。因此，