Nanoparticle Drug Delivery in Post-Pneumonectomy Compensatory Lung Growth

描述(申请人提供)：成年犬的肺切除术(PNX)模拟限制性肺疾病的后果，是一种稳健的代偿性肺生长(CLG)模型，其特征是早期肺泡细胞增殖-肥大，渐进性间隔重塑，腺泡结构逐渐正常化，肺功能在数月内逐渐恢复。PNX后的机械信号几乎激活了所有主要的内稳态通路；下游反应对药物刺激非常敏感，但外源性促进的肺泡组织生长并未反映为功能增强。这种结构-功能差距是该领域翻译进展的关键障碍。造成这种差距的潜在原因包括：a)间隔成分不均匀和/或过度刺激，b)缺乏按比例增强的间隔重塑，以优化气体交换、屏障和最大限度地减少结构扭曲，以及c)需要肺特定滴定的生长促进剂。我们的目标是开发一种平衡促进肺泡生长/重塑的策略，旨在将扭曲降至最低，并增加功能受益的可能性。我们的假设是，持续低剂量吸入纳米颗粒(NP)，为平衡刺激肺泡生长/重塑而选择的补充性促生长剂，可以改善PNX术后的肺结构和功能。生物相容的可生物降解的聚(乳酸-乙醇酸)或PLGA包裹的纳米粒含有已知的生长促进剂：全反式维甲酸(RA)、角质细胞生长因子(KGF)及其受体(KGFR)的多肽或cDNA，或促红细胞生成素(EPO)及其受体(EPOR)，联合应用可按比例刺激肺泡上皮、间质和内皮，促进/保护有益的间隔重建，并保护/恢复正常结构。磁性标签和荧光标记最初可以作为示踪剂加入到纳米颗粒中，但在最终的治疗配方中被省略。目的1：研究含单独和复合促生长剂的纳米粒在人肺细胞中的体外剂量效应、作用时间和生物安全性。优化NP配方，以实现持续释放和适度的作用。目的2：测定复合促生长剂的纳米粒的体内生物学作用。将混悬液中的NPS雾化吸入成年大鼠和试验犬体内，以表征长期给药的生物分布和生物安全性。 目的3：确定NP鸡尾酒对成年犬PNX术后CLG和功能的长期影响。治疗反应将使用非侵入性成像(HRCT和UTE MRI)、生理测试(休息和运动)和详细的结构分析进行监测。这种用于肺再生的新的多途径范例与癌症化疗中使用的方法平行，结合了最先进的纳米技术、成像和生理技术，并建立了跨学科的合作。结果将影响肺再生-修复的基本概念，弥合操纵肺生长的关键知识缺口，并可立即翻译到床边。

DESCRIPTION (provided by applicant): Pneumonectomy (PNX) in adult canines mimics the consequences of restrictive lung disease and is a robust model of compensatory lung growth (CLG), characterized by early alveolar cellular proliferation-hypertrophy, progressive septal remodeling, gradual normalization of acinar architecture and incremental restoration of lung function over many months. Post-PNX mechanical signals activate nearly all the major homeostatic pathways; downstream responses are very sensitive to pharmacological stimulation but exogenously enhanced alveolar tissue growth has not been mirrored by functional enhancement. This structure-function gap represents a key obstacle to translational progress in the field. Potential reasons for the gap include: a) uneven and/or over- stimulation of septal components, b) lack of proportionally enhanced septal remodeling to optimize the gas exchange, barrier and minimize architecture distortion, and c) need for lung-specific titratable delivery of growth promoters. Our goal is to develop a strategy of balanced enhancement of alveolar growth/remodeling aimed at minimizing distortion and increasing the likelihood of functional benefit. Our hypothesis is that sustained low-dose inhalational nanoparticle (NP) delivery of complementary growth-promoting agents selected for balanced stimulation of alveolar growth/remodeling enhances post-PNX lung structure and function. Biocompatible biodegradable poly(lactic-co-glycolic acid) or PLGA-encapsulated NPs will be synthesized each containing a known growth promoter: all-trans retinoic acid (RA), peptide or cDNA of keratinocyte growth factor (KGF) and its receptor (KGFR), or erythropoietin (EPO) and its receptor (EPOR), to be administered in combination to proportionally stimulate the alveolar epithelium, interstitium and endothelium, promote/protect beneficial septal remodeling, and preserve/restore normal architecture. Magnetic tag and fluorescent labels may be incorporated into NPs as tracers initially, but omitted in final therapeutic formulations. Aim 1: Characterize i vitro dose-response, duration of action, and biosafety of NPs containing individual and combination growth promoting agent in human lung cells. Optimize NP formulations for sustained release and modest action. Aim 2: Determine in vivo biological action of NPs containing combinations of growth promoting agents. NPs in suspension will be nebulized into adult rats and pilot dogs to characterize bio-distribution and biosafety of chronic administration. Aim 3: Determine the long-term effects of NP cocktails on post-PNX CLG and function in adult canines. Therapeutic response will be monitored using non-invasive imaging (HRCT and UTE MRI), physiological testing (rest and exercise), and detailed structural analysis. This novel multi pathway paradigm for lung regeneration parallels the approach used in cancer chemotherapy, combines state-of-the-art nanotechnology, imaging and physiological techniques, and forges inter-disciplinary collaborations. Results will impact fundamental concepts of lung regeneration-repair, bridge a key knowledge gap in the manipulation of lung growth, and are immediately translatable to the bedside.