Downregulation of Rod Metabolism in Retinopathy of Prematurity

早产儿视网膜病变中视杆细胞代谢的下调

• 批准号: 7829672
• 负责人: James Daniel Akula
• 金额: $ 40.24万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7829672
• 关键词: Acute; Address; Age; Anatomy; Animals; Area; Attention; Biological Preservation; Birth; Blindness; Blood; Blood Vessels; Cells; Child; Childhood; Computer software; Country; Data; Diagnosis; Disease; Dorzolamide; Down-Regulation; Effectiveness of Interventions; Electroretinography; Enzyme-Linked Immunosorbent Assay; Epidemic; Eye; Eye diseases; Functional disorder; Fundus; Growth Factor; Human; Image; Image Analysis; Incidence; Income; Infant; Intervention; Ions; Light; Measurement; Measures; Medical; Messenger RNA; Metabolic; Metabolism; Modeling; Molecular; Neonatology; Neural Retina; Newly Diagnosed; Oxidative Stress; Oxygen; Pathologic Neovascularization; Patients; Photoreceptors; Play; Prevention; Process; Psychophysiology; Rattus; Recording of previous events; Relative (related person); Research; Retinal; Retinopathy of Prematurity; Role; Semaphorins; Severities; Site; Staining method; Stains; Structure; Techniques; Tetanus Helper Peptide; Time; Tolonium chloride; United States; Vascular Diseases; Vascular Endothelial Growth Factors; Vision; Visual impairment; Western Blotting; Work; base; behavior test; blind; comparative effectiveness; digital; effectiveness research; high risk; improved; molecular marker; novel; pigment epithelium-derived factor; postnatal; preclinical study; public health relevance; pup; research study; retinal neuron; retinal rods; visual cycle

DESCRIPTION (provided by applicant): This proposal outlines a set of experiments under broad challenge area (05) Comparative Effectiveness Research which will address the highest-priority challenge 05-EY-102 Treatment of Pediatric Eye Diseases and Disorders. Specifically, it will compare results from two preclinical trials of novel interventions in retinopathy of prematurity (ROP). In one sense, the continuing ROP epidemic is a good problem to have: Advances in neonatology are permitting the most prematurely born infants to survive. Unfortunately, these are the very patients at highest risk for ROP. Thus, the incidence and severity of ROP in middle income countries is near all-time highs. Worldwide, at least 50,000 children are binocularly blind, many times that number monocularly blind, and many fold again suffering from lifelong visual impairment as a consequence of ROP. In the United States, approximately 15,000 cases are newly diagnosed each year and, despite the best available medical management, 400-600 progress to blindness. This ranks ROP as the leading ocular cause of childhood blindness and strongly motivates research into the effectiveness of interventions. Treatment of the vasculopathy has been the focus of much good work, but the insult to the neural retina has received less attention. Recent discoveries indicate that oxidative stress in the rod photoreceptors plays a causal role in ROP. This inspires an alternative way to treat ROP: modulating rod metabolism. We will conduct a preclinical trial in rat models of ROP by downregulating two energy-demanding processes in the rods: the dark current and the visual cycle. We anticipate that this approach will compare favorably with the best currently available medical management. To produce in rats vascular abnormalities similar to those that characterize human ROP, pups are exposed to high and low oxygen during the first days after birth; the induction ends at postnatal day 14. Rats are grouped two ways: by oxygen exposure history and by treatment. "ROP rats" and controls are assigned to either dark current modulation (DCM) treatment with dorzolamide, visual cycle modulation (VCM) treatment with retinylamine, or vehicle treatment. At around postnatal age 19, when the vascular abnormalities are near their peak (in untreated animals), function of the neural retina (both photoreceptor and postreceptor) is objectively assessed by electroretinography (ERG). Unbiased, numeric measures of abnormality of the superficial vessels are obtained by application of image analysis software (RISA) to digital photographs of the ocular fundus. Both the ERG and retinal imaging are noninvasive techniques that permit subsequent analyses to be conducted in the same eye. A small subset of rats, selected based on the results of their ERG analyses to be near the medians for their group, are assigned to rigorous psychophysical (behavioral) testing of their vision; five threshold measurements (absolute plus four increment) are made in each rat and a transposition of the data, diagonally or vertically relative to controls, will provide clues as to the site of any dysfunction. Detailed anatomic and molecular studies are undertaken in the remaining animals. Assessment of the retinal layers in light micrographs of toluidine blue-stained retinal cross-sections yields information about damage to retinal cells. Markers of oxidative stress are assessed by ELISA and western blotting. qPCR is used to supplement these measures and to evaluate the expression of neurogenic and angiogenic growth factors such as VEGF, PEDF and semaphorins. Improved retinal structure, function and vasculature, as well as reduction in molecular markers of oxidative stress and normalization of growth factor expression, are all hypothesized in both DCM and VCM treated ROP rats. PUBLIC HEALTH RELEVANCE: Retinopathy of prematurity (ROP) is clinically diagnosed by abnormal retinal vasculature, but damage to retinal neurons underpins functional sequelae and may also underpin the vasculopathy. At the same age as the onset of acute vasculopathy, an escalation in the metabolic demands of the rod photoreceptors occurs that simultaneously renders them vulnerable to blood oxygen swings and powerful provocateurs of pathological angiogenesis. Thus, suppression of metabolically demanding processes in the rods promises preservation of visual function and prevention of vascular disease.

描述（由申请人提供）：本提案概述了广泛挑战领域（05）比较有效性研究下的一组实验，这些实验将解决最高优先级挑战05-EY-102儿童眼部疾病和病症的治疗。具体来说，它将比较两项早产儿视网膜病变（ROP）新干预措施的临床前试验结果。从某种意义上说，ROP的持续流行是一个很好的问题：医学的进步使大多数早产儿得以存活。不幸的是，这些患者正是ROP风险最高的患者。因此，中等收入国家ROP的发病率和严重程度接近历史最高水平。在世界范围内，至少有50，000名儿童是双眼盲，是单眼盲的许多倍，并且由于ROP而再次遭受终身视力障碍的许多倍。在美国，每年大约有15，000例新诊断病例，尽管有最好的医疗管理，但仍有400-600例进展为失明。这将ROP列为儿童失明的主要眼部原因，并强烈推动了对干预措施有效性的研究。血管病变的治疗一直是许多好的工作的重点，但神经视网膜的损伤受到较少的关注。最近的发现表明，视杆细胞光感受器中的氧化应激在ROP中起着因果作用。这启发了治疗ROP的替代方法：调节杆代谢。我们将在ROP大鼠模型中进行临床前试验，通过下调视杆细胞中两个需要能量的过程：暗电流和视觉周期。我们预计，这种方法将与目前最好的医疗管理相媲美。为了在大鼠中产生类似于人类ROP特征的血管异常，在出生后的第一天期间将幼仔暴露于高氧和低氧;诱导在出生后第14天结束。大鼠按两种方式分组：按氧气暴露史和按治疗。将“ROP大鼠”和对照分配至用多佐胺进行的暗电流调制（DCM）处理、用视黄胺进行的视觉周期调制（VCM）处理或媒介物处理。在出生后19岁左右，当血管异常接近其峰值时（在未处理的动物中），通过视网膜电图（ERG）客观地评估神经视网膜（光感受器和后感受器两者）的功能。通过将图像分析软件（RISA）应用于眼底的数字照片，获得浅表血管异常的无偏数字测量。ERG和视网膜成像都是非侵入性技术，允许在同一只眼睛中进行后续分析。根据其ERG分析结果选择接近该组中位数的一小部分大鼠，对其视力进行严格的心理物理（行为）测试;在每只大鼠中进行五次阈值测量（绝对值加四次增量），相对于对照组对角或垂直地换位数据，将提供任何功能障碍部位的线索。在其余动物中进行详细的解剖学和分子研究。甲苯胺蓝染色的视网膜横截面的光学显微照片中的视网膜层的评估产生关于视网膜细胞损伤的信息。通过ELISA和蛋白质印迹法评估氧化应激的标志物。qPCR用于补充这些措施，并评估神经源性和血管生成生长因子（如VEGF、PEDF和脑信号蛋白）的表达。在DCM和VCM治疗的ROP大鼠中，都假设了视网膜结构、功能和血管系统的改善，以及氧化应激的分子标志物的减少和生长因子表达的正常化。 公共卫生关系：早产儿视网膜病变（ROP）的临床诊断是异常的视网膜血管，但视网膜神经元的损伤是功能后遗症的基础，也可能是血管病变的基础。在与急性血管病变发作相同的年龄，杆光感受器的代谢需求升级发生，同时使它们容易受到血氧波动和病理性血管生成的强大抑制。因此，抑制视杆细胞的代谢过程有望保护视功能和预防血管疾病。