Smearman Erica L, Yu Tianyi, Brody Gene H
Behavioral Sciences and Health Education Rollins School of Public Health Emory University 1518 Clifton Road Northeast Atlanta Georgia 30322; Center for Translational and Social Neuroscience Emory University Atlanta Georgia 30322.
Center for Family Research University of Georgia 1095 College Station Road Athens Georgia 30602-4527.
Brain Behav. 2016 Jan 17;6(2):e00423. doi: 10.1002/brb3.423. eCollection 2016 Feb.
Parent-child relationships with high conflict and low warmth and support are associated with later adverse behavioral and physiological child outcomes. These outcomes include shorter telomere lengths, the repetitive sequences at the ends of chromosomes that have been utilized as a biomarker for chronic stress. Our research group furthered this by exploring telomere length outcomes following a family-based prevention program and identified reduced telomere shortening 5 years post intervention among those originally exposed to nonsupportive parenting and randomized to the intervention condition. However, not all individuals respond equally, and a growing literature suggests genetic sensitivity to one's environment, with variations in the oxytocin receptor gene (OXTR) potentially influencing this sensitivity.
We utilized data from African American youths (mean age 17) randomized to intervention (n = 100) or control condition (n = 91) with baseline assessments of genetic status and nonsupportive parenting, and 5-year follow-up assessments of telomere length.
We found a significant three-way interaction between nonsupportive parenting, intervention condition, and OXTR rs53576 genotype. OXTR GG individuals, who are suggested to be more sensitive to their social environment, exhibited significantly more variability, evidencing the shortest telomeres when exposed to nonsupportive parenting and randomized to the control condition, and similar telomere lengths to non at-risk groups when randomized to the intervention. In contrast, those with the A allele showed no statistical difference in telomere lengths across parental and intervention conditions. Subsequent analyses suggest that these findings may be mediated through chronic anger, whereby GG individuals exposed to nonsupportive parenting and randomized to the control condition had a greater increase in chronic anger by study follow-up, compared to those in the intervention, and this change associated with greater telomere shortening.
These findings highlight the importance of individual differences and potential role of genetic status in moderating the relationship between environmental contexts and biological outcomes.
高冲突、低温情与支持的亲子关系与儿童后期不良行为及生理后果相关。这些后果包括端粒长度缩短，端粒是染色体末端的重复序列，已被用作慢性应激的生物标志物。我们的研究小组通过探索一项基于家庭的预防计划后的端粒长度结果进一步推进了这一研究，并发现最初暴露于非支持性养育方式且被随机分配到干预组的个体在干预后5年端粒缩短减少。然而，并非所有个体的反应都相同，越来越多的文献表明个体对环境具有遗传敏感性，催产素受体基因（OXTR）的变异可能会影响这种敏感性。
我们利用了非裔美国青少年（平均年龄17岁）的数据，这些青少年被随机分配到干预组（n = 100）或对照组（n = 91），并对其进行了基因状态和非支持性养育方式的基线评估，以及端粒长度的5年随访评估。
我们发现非支持性养育方式、干预组和OXTR rs53576基因型之间存在显著的三向交互作用。OXTR GG个体被认为对其社会环境更敏感，表现出更大的变异性，当暴露于非支持性养育方式并被随机分配到对照组时，端粒最短，而当被随机分配到干预组时，端粒长度与非风险组相似。相比之下，携带A等位基因的个体在不同的父母养育方式和干预条件下端粒长度没有统计学差异。后续分析表明，这些发现可能是通过慢性愤怒介导的，即与干预组相比，暴露于非支持性养育方式并被随机分配到对照组的GG个体在研究随访时慢性愤怒增加更多，而这种变化与更大程度的端粒缩短相关。
这些发现突出了个体差异的重要性以及基因状态在调节环境背景与生物学结果之间关系中的潜在作用。
