OXIDATION AND DEFORMATION IN SICKLE RBC DEHYDRATION

镰状红细胞膜异常最明显地与 镰状病病理生理是赋予异常缺陷 阳离子体内平衡，并最终导致细胞脱水。 的 目前的研究将检查一种新的钾泄漏途径， 过氧化和细胞变形的协同不利影响。 的 所使用的模型是含氧法线的椭圆变形模型 和受过氧化干扰的红细胞 这种变形是通过 剪切应力在粘性悬浮介质中对红细胞的作用 同心圆筒粘度计 将实现五个目标。 一是 阐明过氧化损伤的哪些方面负责 协同泄漏途径，我们将解剖过氧化损伤到其 使用正常RBC的选择性操作的各种组成部分， 如果他们模拟协同泄漏。 第二，我们将研究 这种协同钾渗漏途径的生物物理特征 在过氧化加变形期间观察到。 一些研究将使用 微观力学方法来检测材料的粘结性和材料 从RBC膜脂质提取物重构的脂质体的性质。 其他研究将检查协同增效剂的离子选择性（如果有的话）。 泄漏途径，以及相关的活化能和孔径， 每一个细胞的数量。 直接比较将与 氧合和脱氧镰状红细胞。 第三，可能的相关性 将检查钙稳态的泄漏途径， 可能的阈值（过氧化），超过该阈值， 途径发展成钙依赖性。 第四，我们将确定 这种泄漏途径暴露在变形的镰状红细胞本身中。 这 将通过检查椭圆变形过程中的K+泄漏来解决 氧合镰状红细胞和在脱氧诱导的变形， 正常（或扰动）RBC膜可逆地负载HbS。 最后， 我们将确定相关数据是否支持 镰状红细胞中的自氧化损伤和协同， 过氧化-形变K+渗漏途径。 总的来说，这些 研究将充分确定这种协同泄漏途径，并确定 它是否在镰状红细胞中有效（因此是一种潜在的 镰状红细胞脱水的贡献者）。

The sickle RBC membrane abnormality that is most clearly implicated in sickle disease pathophysiology is that defect which confers abnormal cation homeostasis and, ultimately, leads to cellular dehydration. The present studies will examine a novel potassium leak pathway that reflects synergistic adverse effects of peroxidation and cellular deformation. The model to be used is that of elliptical deformation of oxygenated normal and peroxidatively-perturbed RBC. This deformation is achieved by application of shear stress to RBC in viscous suspending medium using a concentric cylinder viscometer. Five aims will be pursued. First, to clarify what aspects of peroxidative damage are responsible for the synergistic leak pathway, we will dissect peroxidative damage into its various component parts using selective manipulations of normal RBC to see if they simulate the synergistic leak. Second, we will examine the biophysical characteristics of this synergistic potassium leak pathway observed during peroxidation-plus-deformation. Some studies will use micromechanical methods to examine the cohesiveness and material properties of liposomes reconstituted from RBC membrane lipid extracts. Other studies will examine the ion selectivity (if any) of the synergistic leak pathway, as well as relevant activation energies and pore size and number per cell that develop. Direct comparison will be made with oxygenated and deoxygenated sickle RBC. Third, the possible relevance of this leak pathway to calcium homeostasis will be examined as will a possible threshold (of peroxidation) beyond which the synergistic leak pathway develops a calcium-dependence. Fourth, we will determine whether this leak pathway is exposed in deforming sickle RBC themselves. This will be addressed by examining K+ leak during elliptical deformation of oxygenated sickle RBC and during deoxygenation-induced deformation of normal (or perturbed) RBC membranes reversibly loaded with HbS. Finally, we will determine whether correlative data support a relationship between autoxidative damage in sickle RBC and development of the synergistic, peroxidation-plus-deformation K+ leak pathway. In aggregate, these studies will fully define this synergistic leak pathway and determine whether it is operative in sickle RBC (and is, therefore, a potential contributor to sickle RBC dehydration).