OXIDATIVE STRESS AND ANTIOXIDANTS IN IRON OVERLOAD

描述（改编自应用程序） 心脏功能障碍提供了铁的最直接的证据 毒性，心力衰竭一直是最常见的死亡原因， 血色素沉着症患者。我们已经证明，即使是轻微的铁超载， 促进缺血后心脏的损伤。我们还发现β受体阻滞剂 普萘洛尔可在内皮细胞溶酶体中蓄积， 和心脏保护免受氧化损伤。本申请基于 两种假设：1）内皮细胞中的溶酶体是主要的储存位点 并提供可释放的氧化还原活性低分子的主要来源 铁，它可以增强心血管损伤，以应对氧化应激 (e.g.缺血/再灌注和外源性氧化剂）。2)稳定 在氧化应激前通过选择的亲脂性β-受体阻滞剂对溶酶体铁的影响 会减轻细胞和心脏的损伤通过使用培养的 内皮细胞和大鼠心脏模型，我们建议研究以下内容 目的：1）确定溶酶体铁对内皮细胞的贡献， 由于铁超负荷和随后的氧化应激导致的心脏损伤。（二） 确定所选β受体阻滞剂和类似物是否导致溶酶体碱化 将伴随着铁负载的氧化应激降低 内皮细胞3)确定β受体阻滞剂类似物治疗是否 减轻铁负荷大鼠心脏的氧化应激。4)评估是否 长期的药物预处理会减少细胞和组织的铁 积累将采用各种复杂的技术来评估 自由基的产生和氧化损伤（ESR自旋捕获，脂质 过氧化产物和抗氧化剂定量），总和低分子量 铁定量（X射线微量分析，钙黄绿素荧光指示剂，NO-ESR 技术），以及组织和细胞毒性（心肌功能和细胞毒性 生存）。我们相信我们提出的研究可能会导致重新评估 β受体阻滞剂在铁超载治疗中的潜在用途。

DESCRIPTION (adapted from the application) Disorders of cardiac function have provided the most direct evidence of iron toxicity, and cardiac failure has been the most common cause of death in patients with hemochromatosis. We have shown that even mild iron-overload promotes injury to the postischemic heart. We also showed that the beta-blocker propranolol could accumulate in endothelial lysosomes and provide both cellular and cardiac protection against oxidative injury. This application is based upon two hypotheses: 1) Lysosomes in the endothelial cells are major storage sites of iron and provides a primary source of releasable redox active low molecular iron, which can enhance cardiovascular injury in response to oxidative stress (e.g. ischemia/reperfusion and exogenous oxidants). 2) Stabilization of lysosomal iron by selected lipophilic beta-blockers prior to oxidant stress will attenuate cellular and cardiac injury. By using both the cultured endothelial cell and rat heart models, we propose to investigate the following aims: 1) Determine the contribution of lysosomal iron to endothelial cell and cardiac injury due to iron-overload and subsequent oxidative stress. 2) Determine if alkalinization of lysosomes by selected beta-blockers and analogs will be accompanied by decreased oxidative stress in the iron-loaded endothelial cells. 3) Determine if treatment with beta-blocker analogs will attenuate oxidative stress in hearts from iron-loaded rats. 4) Assess if long-term pre-treatment with the drugs reduce cellular and tissue iron accumulation. A variety of sophisticated techniques will be employed to assess free radical production and oxidative injury (ESR spin trapping, lipid peroxidation products and antioxidant quantification), total and low molecular iron quantification (X-ray microanalysis, Calcein fluorescent-indicator, NO-ESR technique), and tissue and cellular toxicity (myocardial function and cell survival). We believe our proposed studies may lead to a reassessment of the potential use of beta-blockers for iron-overload therapy.