Testing tobacco smoke toxicity at the blood-brain barrier

描述(申请人提供)：吸烟被认为是一项重大的公共卫生挑战，仅在美国每年就导致40多万人死亡。为了降低烟草烟雾(TS)对健康造成的损害风险，烟草行业正在营销和广告一系列“减少暴露”的烟草产品(如Brown&Williamson烟草公司制造的“Advance”、矢量集团有限公司制造的“Omni”和Quest 3)，这些产品声称比领先的“轻”卷烟品牌危害小。然而，提供的科学证据不足以评估这些产品是否确实降低了吸烟者患烟草相关疾病的风险，包括与血管损伤有关的疾病。尽管有强有力的证据表明烟草烟雾与血管损伤之间存在关联，但TS暴露对血脑屏障(BBB)的影响仅被略微提及，研究仅限于TS中数千种选择性物质中的少数几种，因此使BBB研究成为一个研究较少的领域。为了解决这些公众对健康的担忧，我们提出了一种多模式方法，涉及并行使用1)新型人源化体外动态BBB模型；2)新鲜分离的吸烟者和非吸烟者志愿者的外周血免疫细胞(PBMC)和血小板；3)3)大鼠局灶性脑缺血模型，将用于补充体外研究结果，并评估TS暴露(常规暴露和“减少暴露”)与暂时性血流丧失协同作用引起继发性脑损伤(脑水肿)的可能性和严重程度。基于这些前提，我们建议：1.评估来自减少接触和常规烟草产品的烟草烟雾对血脑屏障完整性和功能的影响，并评估每种烟草产品的免疫活性。2.观察TS暴露对大鼠血脑屏障功能和生存能力的影响，探讨TS暴露对继发性脑损伤发病机制的影响。 公共卫生相关性：主动和被动吸烟与血管内皮生理功能障碍之间存在因果关系和剂量依赖关系。尽管有强有力的证据表明烟草烟雾与血管损伤之间存在关联，但TS暴露对血脑屏障(BBB)的影响仅被略微提及，研究仅限于TS中数千种选择性物质中的少数几种，因此使BBB研究成为一个研究较少的领域。为了解决这些关键问题，我们建议评估来自减少暴露的烟草产品和常规烟草产品的烟草烟雾对血脑屏障完整性和功能的影响。我们还建议研究TS暴露对血脑屏障功能和生存能力的影响，并与流变学变化协同作用，以及这可能如何影响继发性脑损伤的发病机制。本提案是对PA-09-046的响应。这份计划公告特别要求探索各种烟草和尼古丁产品的不同毒性。在这方面，我们相信，我们的研究将在一个未被考虑的健康领域对烟草烟雾毒性的认识产生显著影响，并将为进一步的研究提供基础。

DESCRIPTION (provided by applicant): Tobacco smoking is considered a major public health challenge, responsible for more than 400,000 deaths each year in the United States alone. To reduce the risk of health damage caused by tobacco smoke (TS) the tobacco industry is marketing and advertising a line of "reduced-exposure" tobacco products (such as "Advance" manufactured by Brown & Williamson Tobacco Corporation, "Omni" and Quest 3 manufactured by Vector Group Ltd), which claim to be less harmful than the leading "light" cigarette brands. However, the scientific evidence provided is insufficient to evaluate whether these products actually reduce the users' risk for tobacco-related diseases including those associated to vascular impairments. Despite the strong evidence for an association between tobacco smoke and vascular impairment, the impact of TS exposure on the blood-brain barrier (BBB) has been only marginally addressed and studies were limited to only few selective substances among the thousands contained in TS thus, leaving BBB research a substantial understudied area. To address these relevant health public concerns we propose a multimodal approach that involve the parallel use of 1) a novel humanized dynamic in vitro BBB model; 2) freshly isolated peripheral blood immune cells (PBMC) and platelets from smoker and non-smoker volunteers; 3) 3 vessel occlusion rat models of focal ischemia that will be used to complement the results in vitro and assess the likelihood and magnitude of secondary brain injury (brain edema) caused by TS exposure (from regular and "reduced-exposure") in synergism with temporary loss of blood flow. Based on these premises we propose to: 1. Evaluate the effect of tobacco smoke from reduced-exposure and regular tobacco products on BBB integrity and function and assess the immunoactivity of each tobacco product. 2. Investigate the effect of TS exposure on BBB function and viability in synergism with rheological changes and how this may impact the pathogenesis of secondary brain injury. PUBLIC HEALTH RELEVANCE: Active and passive tobacco smoking are associated with dysfunction of vascular endothelial physiology in a causative and dose dependent way. Despite the strong evidence for an association between tobacco smoke and vascular impairment, the impact of TS exposure on the blood-brain barrier (BBB) has been only marginally addressed and studies were limited to only few selective substances among the thousands contained in TS thus, leaving BBB research a substantial understudied area. To address these critical issues, we propose to evaluate the effect of tobacco smoke from reduced-exposure and regular tobacco products on BBB integrity and function. We also propose to investigate the effect of TS exposure on BBB function and viability in synergism with rheological changes and how this may impact the pathogenesis of secondary brain injury. This proposal is in response to the PA-09-046. This program announcement specifically asks to explore the differential toxicity of various tobacco and nicotine products. In this respect, we believe that our study will produce a remarkable impact on the awareness of tobacco smoke toxicity in an under considered health area and will provide the foundations for additional studies.