Do Hair Cortisol and Hair Oxytocin represent the Stressful and Supportive Experiences of Preschool Children?

早期生活压力(ELS)可以破坏神经、心血管、新陈代谢和免疫的发育。 导致一生中身心健康状况不佳。ELS在中国的患病率不断上升 学龄前儿童是一个主要的公共卫生问题，从流行病学上讲，学龄前儿童与较高的青少年比例有关 自杀、约会暴力、酗酒和吸毒。个体对急性压力的反应是释放皮质醇； 因此，头发皮质醇浓度(HCC)可以量化儿童在反复或慢性压力下的暴露情况。 我们关于肝癌的初步数据揭示了与学龄前儿童慢性应激相关的各种因素。 我们建议将头发催产素浓度(HOC)作为支持性和/或社会性的终结性指标 从属体验。拟议研究的具体目标是：(1)验证用于测量的新的分析方法 对1200名学龄前儿童及其父母进行了肝癌和HOC的调查，以量化他们的累积暴露于 (2)测量头发成分(蛋白质、脂肪、水分) 解释和/或调整从学龄前儿童及其家长那里获得的HC和HOC值。 我们正在收集1-5岁儿童(n=1200)和至少一名陪同父母的头发样本 (n=1200)。从父母那里，我们获得他们孩子的人口统计、发育、健康和环境数据。 头发样本使用我们的新提取方法进行处理，并使用特定的酶连接进行分析 肝细胞癌和肝细胞癌的免疫吸附试验(ELISA)；这些试验使用超高性能液体进行验证 色谱联用串联质谱仪(UPLC/MS-MS)。我们用来测量头发成分的 直接分光光度检测。完成后，这些数据将建立肝细胞癌和 HOC在学龄前儿童中的表现，并研究与以下因素有关的肝癌、HOC和头发成分的自然变化 年龄、性别、种族、民族、父母、社会经济或其他因素。HOC和HOC的值从 同样的头发样本也将允许我们检查催产素介导的皮质醇对ELS反应的调节。 由于疫情相关的封锁和对学前班或托儿所的限制，招生工作被叫停 自2020年3月以来。为了使受试者能够登记，研究方案被修改为“无接触”的方法 于2021年2月启动，这也将使我们能够检查新冠肺炎大流行对 学龄前儿童所经历的长期压力和社会联系。 我们有一支多学科的团队、设备、经验和试验数据来成功完成 提议的项目。这项研究的完成将为肝癌和HOC提供特定年龄的参考标准 在健康的学龄前儿童中。该项目将解决我们当前知识中的根本差距 建立一个科学的框架来调查早期健康对身心健康的长期影响 童年压力，在身体或心理创伤之后，创伤/中毒压力，与暴力有关的伤害， 虐待儿童以及急性或危重疾病--被NICHD确定为高度优先的研究领域。

Early life stress (ELS) can disrupt the development of nervous, cardiovascular, metabolic, and immune systems, leading to poor physical and mental health throughout the lifespan. The rising prevalence of ELS in preschool children is a major public health concern, epidemiologically linked with higher rates of youth suicides, dating violence, drinking, and drug abuse. Individuals respond to acute stress by releasing cortisol; thus, hair cortisol concentrations (HCC) can quantify the exposures to recurrent or chronic stress in children. Our pilot data on HCC revealed various factors that are associated with chronic stress in preschool children. We propose hair oxytocin concentrations (HOC) as a summative measure of supportive and/or socially affiliative experiences. Specific aims of the proposed study are: (1) to validate novel assays for measuring HCC and HOC in 1200 preschool children and their parents, in order to quantify their cumulative exposures to stressful vs. supportive early experiences; and (2) to measure hair composition (protein, lipid, water content) to interpret and/or adjust the HCC and HOC values obtained from the preschool children and their parents. We are collecting hair samples from children ages 1-5 years (n=1200) and at least one accompanying parent (n=1200). From parents, we obtain their child’s demographic, developmental, health and environmental data. Hair samples are processed using our novel extraction methods and analyzed using specific enzyme-linked immunosorbent assays (ELISA) for HCC and HOC; these assays are validated using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC/MS-MS). We measure hair composition using direct spectrophotometric detection. On completion, these data will establish the reference norms for HCC and HOC in preschool children and examine the natural variations in HCC, HOC, and hair composition in relation to age, sex, race, ethnicity, parental, socioeconomic, or other factors. HCC and HOC values obtained from the same hair sample will also allow us to examine oxytocin-mediated regulation of the cortisol responses to ELS. Enrollment was halted due to pandemic-associated lockdowns and restrictions on preschool or childcare sites since March 2020. To enable subject enrollment, the study protocol was modified to a “contact-free” approach launched in February 2021, which will also allow us to examine effects of the COVID-19 pandemic on the chronic stress and social affiliation being experienced by preschool children. We have a multidisciplinary team, the equipment, the experience, and the pilot data to successfully complete the proposed project. Completion of this research will provide age-specific reference norms for HCC and HOC in healthy preschool children. This project will address fundamental gaps in our current knowledge and establish a scientific framework to investigate long-term physical and mental health consequences of early childhood stress, following physical or psychological trauma, traumatic/toxic stress, violence-related injury, child maltreatment, and acute or critical illnesses – identified as a high-priority research area by NICHD.