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，代谢和免疫系统的发育。 系统，导致整个生命周期的身心健康状况不佳。ELS的日益流行， 学龄前儿童是一个主要的公共卫生问题，在流行病学上与青年发病率较高有关。 自杀约会暴力酗酒和吸毒个体通过释放皮质醇对急性压力做出反应; 因此，头发皮质醇浓度（HCC）可以量化儿童反复或慢性压力的暴露。 我们关于HCC的试点数据揭示了与学龄前儿童慢性压力相关的各种因素。 我们建议头发催产素浓度（HOC）作为支持性和/或社会性的总结性措施， 亲和体验本研究的具体目的是：（1）验证新的测定方法， 1200名学龄前儿童及其父母的HCC和HOC，以量化他们的累积暴露， 压力与支持性早期经验;（2）测量头发成分（蛋白质，脂质，水含量） 解释和/或调整从学龄前儿童及其父母获得的HCC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、发展、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，并使用特定的酶联免疫吸附试验进行分析。 用于HCC和HOC的免疫吸附测定法（ELISA）;这些测定法使用超高效液相色谱法进行验证。 通过柱色谱法与串联质谱法（UPLC/MS-MS）偶联来分析。我们测量头发成分， 直接分光光度检测完成后，这些数据将建立HCC的参考标准， HOC在学龄前儿童和检查HCC，HOC的自然变化，头发成分与 年龄、性别、种族、民族、父母、社会经济或其他因素。HCC和HOC值从 同样的头发样本也将使我们能够检查催产素介导的皮质醇对ELS反应的调节。 由于与流行病相关的封锁和对学前班或儿童保育场所的限制， 自2020年3月以来。为了能够入组受试者，将研究方案修改为“无接触”方法 于2021年2月推出，这也将使我们能够研究COVID-19大流行对 学龄前儿童所经历的慢性压力和社会关系。 我们拥有一支多学科的团队、设备、经验和试点数据， 拟议的项目。这项研究的完成将为HCC和HOC提供年龄特异性参考标准 健康的学龄前儿童。该项目将解决我们目前知识的根本差距， 建立一个科学框架，调查早期吸毒对身心健康长期影响， 儿童时期的压力、身体或心理创伤后的压力、创伤/中毒压力、与暴力有关的伤害， 虐待儿童和急性或严重疾病-被国家排雷中心确定为高度优先研究领域。

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.