Mechanism of intravitreal VEGF-A165a and topical calcitriol for the treatment of retinopathy of prematurity

项目总结 Olachi Mezu-Ndubuisi博士是一名新生儿专家，曾接受过验光师培训，现在是一名助理 儿科学教授，附属机构在加州大学眼科系任职 威斯康星州(UW)。她在研究早产儿视网膜病变(ROP)时结合了这些经验。 ROP是早产儿视网膜血管异常形成的一种双相疾病，其特征是 血管内皮生长因子(VEGF)调节失调。ROP没有治愈方法，现有的治疗方法有 不利的系统性影响和长期赤字。Mezu-Ndubuisi博士开发了一种非侵入性方法 用荧光素显示氧诱导视网膜病变(OIR)小鼠模型的视网膜血管 血管造影术。她将活体视网膜血管变化(动脉曲折、静脉扩张和毛细血管)联系起来 血管)的结构和功能，并进行组织学研究，以显示独特的长期特征 OIR小鼠表现为细胞凋亡延长、神经胶质细胞活化和突触异位形成。拥有 定义了体内和组织学的OIR表型，她寻求使用分子技术来增强 了解血管内皮生长因子在ROP中的调控，以开发安全有效的治疗方法。在她的预赛中 研究表明，在出生后第13天，即第二阶段的早期，小鼠体内的Vegfa164总水平增加了6倍 OIR小鼠的ROP，与RA小鼠相比，Vegfa164b显示出OIR趋势是RA小鼠的1.3倍 P10(高氧期视网膜血管闭塞高峰)。这表明，血管内皮生长因子亚型的不平衡 出现在ROP中。然后，她将促血管生成的亚型血管内皮生长因子-A165，血管内皮生长因子-A165a 释放微粒，导致更早的视网膜血管重建，改善动脉曲折和静脉 扩张。接下来，她将局部使用的骨化三醇(维生素D的活性形式)滴眼液与腹腔注射的骨化三醇(IP)进行了比较 在第二期ROP后期，两者都抑制视网膜血管生成，但局部应用骨化三醇不会导致生长受限 就像ip骨化三醇。Mezu-Ndubuisi博士假设，在第二阶段的早期和局部使用玻璃体内注射VEGF-A165a 骨化三醇在第二阶段后期，将挽救体内异常的OIR和组织学表型。在这本K08中，Dr。 Mezu-Ndubuisi将确定玻璃体内最有效和毒性最低的VEGF微粒剂量 玻璃体内注射VEGF蛋白和局部应用骨化三醇治疗2期ROP(AIM 1)，然后研究其分子机制 通过血管内皮生长因子-A165a和骨化三醇调节ROP的血管生成信号(目标2)。UW提供了出色的 致力于Mezu-Ndubuisi博士的学术环境、最先进的设施和学术资源 成功。她得到了来自NIH知名调查人员的强大的壁内和壁外指导 ROP、分子遗传学、血管生成和维生素D方面的专家Mezu-Ndubuisi博士的职业目标和 目标包括一项详细的培训计划，以增加她在生物统计学、生物化学、 组织病理学、分子信号、研究伦理和实验室技能。这将使她成功地 她的研究过渡到研究独立和临床翻译。

PROJECT SUMMARY Dr. Olachi Mezu-Ndubuisi is a neonatologist with a background training as an optometrist, now an Assistant Professor of Pediatrics with an affiliate appointment in the Department of Ophthalmology at University of Wisconsin (UW). She combines these experiences in her research studying Retinopathy of Prematurity (ROP). ROP is a bi-phasic disease of abnormal retinal vascularization in premature infants, characterized by dysregulation of vascular endothelial growth factor (VEGF). ROP has no cure, and existing therapies have adverse systemic effects and long-term deficits. Dr. Mezu-Ndubuisi developed a non-invasive method of visualizing retinal blood vessels in a mouse model of oxygen-induced retinopathy (OIR) using fluorescein angiography. She correlated in vivo retinal vascular changes (arterial tortuosity, venous dilation, and capillary vascularity) to structure and function, and performed histological studies to show unique long-term features of OIR mice, such as prolonged cellular apoptosis, glial activation, and ectopic formation of synapses. Having defined the in vivo and histologic OIR phenotypes, she seeks to use molecular techniques to enhance understanding of VEGF regulation in ROP in order to develop safe and effective therapies. In her preliminary studies, there was a 6-fold increase in total mouse Vegfa164 levels at post-natal day (P) 13, early in Phase 2 ROP, in OIR mice compared to RA mice, and Vegfa164b showed a 1.3-fold higher trend in OIR than RA mice at P10 (peak of retinal vaso-obliteration during hyperoxia). This suggests that an imbalance of VEGF isoforms occurs in ROP. She then administered the pro-angiogenic isoform of VEGF-A165, VEGF-A165a, in sustained release microparticles which resulted in earlier retinal revascularization with improved arterial tortuosity and vein dilation. She next compared topical calcitriol (active form of vitamin D) eyedrop to intraperitoneal (IP) calcitriol and both inhibited retinal angiogenesis later in Phase 2 ROP, but topical calcitriol did not cause growth restriction like IP calcitriol. Dr. Mezu-Ndubuisi hypothesizes that using intravitreal VEGF-A165a early in Phase 2 and topical calcitriol later in Phase 2, would rescue the abnormal OIR in vivo and histologic phenotypes. In this K08, Dr. Mezu-Ndubuisi will determine the most effective and least toxic dose of intravitreal VEGF microparticles or free intravitreal VEGF protein and topical calcitriol in Phase 2 ROP (Aim 1), and then study the molecular mechanisms by which VEGF-A165a and calcitriol regulate angiogenic signaling in ROP (Aim 2). UW provides an excellent academic environment, state-of-the-art facilities, and academic resources dedicated to Dr. Mezu-Ndubuisi’s success. She has strong intra-mural and extra-mural mentoring from well-established NIH investigators and experts in ROP, molecular genetics, angiogenesis, and Vitamin D. Dr. Mezu-Ndubuisi’s career goals and objectives include a detailed training plan to increase her knowledge in biostatistics, biochemistry, histopathology, molecular signaling, and research ethics and laboratory skills. This will enable her successful transition to research independence and clinical translation of her research.