Reactive nitrogen species and cardiovascular aging

这项试点拨款申请是为了探索自由基和氧化剂介导的血管功能改变与衰老相关的某些方面。与衰老相关的内皮损伤和血管功能障碍与局部自由基相关的过程有关，并在衰老相关的各种血管并发症（包括动脉粥样硬化）的发病机制中发挥作用。这种内皮细胞死亡和损伤的药理调节可能为与衰老相关的血管功能障碍的实验治疗提供新的途径。我们在培养的内皮细胞中获得了初步的数据，氧化剂在内皮细胞附近进行，引发细胞内级联反应，最终由核酶聚核糖合成酶（PARS）控制。这导致PARS激活，启动能量消耗周期，导致细胞功能障碍和内皮细胞一氧化氮生成受损。我们的初步数据还表明，PARS的药理抑制或基因失活可减少氧化介导的内皮损伤的发生。在目前的试点研究项目中，我们冒险进入衰老领域，探索过氧亚硝酸盐/PARS通路在衰老血管中的重要性。我们的工作假设是，在老化的脉管系统中，由于抗氧化能力的降低和氧化剂生成的增加，发生了活性氮的形成和PARS的激活。在本研究的第一个目的中，我们将通过比较成年大鼠和老年大鼠血管中活性氮的生成、血管反应性和PARS的激活，来探索上述途径激活的时间过程。在第二个具体目标中，使用PARS药物抑制剂进行慢性治疗将解决PARS是否导致与衰老相关的内皮功能丧失的问题。我们的研究将提供1。与衰老相关的内皮功能障碍的新机制信息。为后续研究血管老化过程中过氧硝酸盐/PARS通路的全额资助申请提供初步数据。

This pilot grant application is submitted to explore certain aspects of free radical and oxidant mediated alterations of vascular function associated with aging. Endothelial injury and vascular dysfunction associated with aging is related to local, free radical-related processes, and plays a role in the pathogenesis of various vascular complications associated with aging (including atherosclerosis). Pharmacological modulation of this endothelial cell death and injury may provide novel avenues for the experimental therapy for the vascular dysfunction associated with aging. We have obtained preliminary data in cultered endothelial cells that oxidants proceeded in the vicinity of endothelial cells trigger an intracellular cascade culminating governed by the nuclear enzyme poly (ADP-ribose) synthetase (PARS). This results in activation of PARS which initiates an energy consuming cycle, with resultant cell dysfunction and impaired endothelial nitric oxide generation. Our preliminary data also demonstrated that pharmacological inhibition or genetic inactivation of PARS reduces the development of oxidant- mediated endothelial injury. In the current pilot research project we venture into the area of aging to explore the importance of the peroxynitrite/PARS pathway in aging blood vessels. Our working hypothesis is that in the aging vasculature, due to the reduced anti- oxidant capacity, and the increased oxidant generation, reactive nitrogen species formation and PARS activation occurs. In the first aim of the study, by comparing reactive nitrogen species generation, vascular reactivity and PARS activation in the blood vessels from adult and aged rats, we will explore the time course of the activation of the above described pathway. In the second specific aim, chronic treatment with pharmacological inhibitors of PARS will address the question whether PARS contributes to the loss of endothelial function associated with aging. Our studies will provide 1. novel mechanistic information on aging-related endothelial dysfunction and 2. preliminary data for a subsequent full grant application to study the peroxynitrate/PARS pathway in the process of vascular aging.