Toxicology study of emissions from a burn pit simulator

军事废物焚烧排放的含碳(即含碳)颗粒物 烧伤坑与部署后的突发疾病有关，如海湾战争疾病(GWI)。GWI是一家 一种综合征，本来身体健康的士兵回来时会出现从急性呼吸道到令人虚弱的症状 炎症导致慢性内分泌功能受损。它是如何发展起来的还不得而知。为了让人们明白 针对军用焚烧炉排放对GWI值的影响，我们建议对燃烧环境进行评价。 使用我们建造的模拟器，了解这些环境如何有助于有毒物质的形成。至 确定潜在的机制，我们的直接目标是修改和校准模拟器。然后，我们将同步- 代表烧伤坑排放物的碳质PM的大小，并将其暴露于哺乳动物细胞系。 该模拟器是在实验室规模上运行的，据我们所知，它是唯一一种此类模拟器 在VA系统内，能够可靠地再生军用焚烧炉排放的含碳PM(和气体)。 模拟器的设计允许调节各自入口气流中的进料(燃料、氧气和氮气)。 调节这三个独立变量的能力提供了对结构和温度的严格控制 在PM合成之前的火焰。结果，PM的物理和化学性质可以 预测到了。我们将为混合物生成一个统计设计的全析因实验。在这种方法中，我们 将对PM的大小、形状、电荷和表面积体积比以及多环芳烃进行表征 碳氢化合物(PAH)含量，并将这些响应绘制为自变量的函数。他们的回应 表面方法论(RSM)是一种统计工具，在工程中常用，它将允许我们探索 调节火焰结构和温度的三个独立因素与 用最少的实验次数来确定PM的性质。而几个多环芳烃分子存在于 气相是有毒的，已知的致癌物是吸附在或沉积在其中的较大的疏水分子 首相为了将PM的毒理作用与气态物质分离，我们将在过滤器上收集PM。 我们将PM样品消毒并分散在细胞培养基中。为了确保分散体的稳定性， 我们将使用动态光散射(DLS)测量来记录它们的大小和Zeta电位，以及沉积物- 周转率。细胞活力将通过电池-底物阻抗传感(ECIS)进行监测。ECIS措施 组织培养板底部的两个金电极的总电阻抗，因此细胞活力 是由细胞附着覆盖的金电极面积决定的。将监测生物兼容性 通过细胞凋亡(细胞死亡)和使用化学发光测量产生的活性氧(ROS)- 曼茨。ROS测量是细胞氧化应激的指示；对健康不利的环境 细胞功能。最后，为了在分子水平上确定PM启动的化学途径，我们将 进行RNA测序。在细胞出现死亡或脱离电极的迹象之前，我们将提取 总RNA。然后，RNA将在华盛顿的基因组技术访问中心(GTAC)进行分析 大学。通过GTAC，我们将确定哪些基因在每个细胞系COM中表达不足或过表达。 削减以控制细胞系。我们预计这些数据将说明碳质PM对细胞的影响。 通过最初排除军事人员遇到的其他类型的PM(例如，金属的，卤化的， 杂环，或矿物)我们将能够准确地定位多环芳烃启动的途径，我们认为这些途径是显著重新- 对于GWI来说是可接受的。这将作为指导研究(使用真实材料)的努力的基础 承担了。在确定了真正的碳质PM如何致病后，我们将探索治疗方案。

Carbonaceous (i.e., carbon-containing) particulate matter (PM) emitted by the combustion of waste in military burn pits is associated with post-deployment sudden illnesses, such as the Gulf War Illness (GWI). GWI is a syndrome where otherwise healthy soldiers return with debilitating conditions ranging from acute respiratory inflammations to chronic impaired endocrine function. The nature by which it develops is unknown. To shed light over the effect of military burn pit emissions contributing to GWI, we propose to evaluate the combustion envi- ronments within, using a simulator we built, and understand how these are conducive to toxicant formation. To identify underlying mechanisms, our immediate goal is to modify and calibrate the simulator. Then, we will syn- thesize carbonaceous PM representative of burn pit emissions and expose it to mammalian cell lines. The simulator operates on the bench scale and, to the best of our knowledge, is the only one of its kind within the VA system capable of reliably reproducing carbonaceous PM (and gases) emitted by military burn pits. The simulator’s design allows modulation of the feed (fuel, oxygen, and nitrogen) in the respective inlet streams. The ability to modulate these three independent variables offers tight control over the structure and temperature of the flame that precedes PM synthesis. As a result, the physical and chemical properties of the PM can be predicted. We will generate a statistically designed full-factorial experiments for mixtures. In this approach, we will characterize the PM for size, shape, charge, and surface area-to-volume ratio as well as polycyclic aromatic hydrocarbon (PAH) content, and plot these responses as a function of the independent variables. The response surface methodology (RSM) is a statistical tool, used commonly in engineering, which will allow us to explore the relationship between the three independent factors (that regulate the flame structure and temperature) and the properties of the PM using the least number of experiments. While several PAH molecules that exist in the gas-phase are toxic, the known carcinogens are larger hydrophobic molecules adsorbed on or deposited within the PM. To separate the toxicological effect of PM from the gaseous species, we will collect PM on filters. We will sterilize and disperse the PM samples in cell culture media. To ensure the dispersions are stable, we will record their sizes and zeta potentials using dynamic light scattering (DLS) measurements, and sedimen- tation rates. Cell viability will be monitored by electric cell-substrate impedance sensing (ECIS). ECIS measures the total electrical impedance across two gold electrodes at the bottom of the tissue culture plates, so cell viability is determined by the area of the gold electrodes covered by cell attachment. Biocompatibility will be monitored by apoptosis (cell death) and reactive oxygen species (ROS) generation using chemiluminescence measure- ments. ROS measurements are an indication of oxidative stress to the cells; an environment adverse for healthy cell function. Finally, to determine the chemical pathways initiated by the PM at the molecular level, we will perform RNA sequencing. Before the cells show signs of death or detachment from the electrode, we will extract the total RNA. The RNA will then be analyzed in the Genome Technology Access Center (GTAC) at Washington University. Through GTAC we will determine which genes are under- or over-expressed in each cell line com- pared to control cell lines. We anticipate this data will illustrate the effects of carbonaceous PM on the cells. By initially excluding other types of PM encountered by military personnel (e.g., metallic, halogenated, heterocyclic, or mineral) we will be able to pinpoint PAH-initiated pathways that we believe are significantly re- sponsible for GWI. This will serve as a foundation to direct efforts on how studies (using real material) are to be undertaken. After identifying how real carbonaceous PM causes disease, we will explore therapeutic options.