A Novel Resolution Strategy for Chronic Inflammation and Impaired Healing of Wounds in Aging

摘要 创伤相关的慢性炎症是阻碍创伤愈合的关键因素，但目前尚无有效的治疗方法 用于治疗老年人的不愈合伤口。这一R21项目是根据“PA-16- 2000”提交的， 231不愈合的溃疡伤口在老化，”将探索一种新的翻译策略，解决慢性 炎症和老化中不愈合溃疡的恢复愈合。慢性炎症的消退至关重要 用于恢复愈合过程，并且似乎需要maresin样脂质介质（MarLs）的作用， 其由巨噬细胞（巨噬细胞）产生，解决炎症并促进伤口愈合。我们长久以来- 长期目标是克服衰老对伤口愈合的损害。为了实现这一目标，我们发现， 内源性创伤MarLs（MarL 1和MarL 3，来源于ω-3二十二碳六烯酸）逆转了这一点 损伤我们已发表的数据表明，MarL 3可促进糖尿病伤口愈合并促进 修复性VEGF、PDGF-BB和IL 10的表达，以及向修复性M β的转变， 通过PI 3 K信号传导。MarL 3还通过内皮细胞促进伤口血管生长和VEGF形成。 细胞相比之下，MarL 1促进再生生长因子HGF的产生，并减弱M. 促炎性TNFα的产生。MarL 1还增强了M β促进的上皮细胞迁移， 成纤维细胞和干细胞。将MarL 1应用于老年小鼠的伤口改善愈合。但 MarLs的治疗潜力是有限的，因为局部应用的MarLs在一定时间内从伤口中消除， 几个小时，而伤口愈合需要几天。伤口愈合还涉及多个过程， 这是一个长期的过程，其中许多步骤可以通过MarLs来促进。在初步研究中，我们 使用包埋在基于氨基酸（精氨酸）的 聚（酯酰胺）蛋白质模拟物（AA-PEA）微粒（μPs）。AA-PEAs是新一代的 生物相容性、生物可降解性和无毒的生物材料。包埋在AA-PEA-µPs中的MarL 1是 比单独的MarL 1更有效地促进衰老中的伤口闭合。我们的假设是， 将MarL释放到伤口将解决炎症并克服愈合的老化损伤。我们 目的是开发和评估我们创新的微P缓释MarLs的能力， 老年人的伤口愈合具体目标1。A）开发装载MarL的微处理器，以控制和维持MarL- 释放到老年小鼠的伤口，并确定伤口中MarL释放的动力学。B）确定最佳 从µ P中持续释放MarL以及用于缓解炎症和恢复愈合的给药方案 （再上皮化、血管再生、皮肤断裂强度）。本项目将使用µPs- 持续释放的MarLs，以确定一个创新的战略以及治疗线索，以克服 老年人不愈合伤口的愈合障碍。它还将提供有关 老化中炎症消退与伤口愈合之间的时间关系。

ABSTRACT Age-related chronic inflammation is a key factor that prevents wound healing, but no effective therapy currently exists to cure non-healing wounds in the aging population. This R21 project, submitted in response to “PA-16- 231 Non-healing Ulcerative Wounds in Aging,” will explore a novel translational strategy for resolving chronic inflammation and restoring healing of non-healing ulcers in aging. Resolution of chronic inflammation is critical for restoration of healing process and appears to require the action of maresin-like lipid mediators (MarLs), which are produced by macrophages (Ms), resolve inflammation, and promote wound healing. Our long- term goal is to overcome the impairment of wound healing in aging. Toward this goal, we discovered that two endogenous wound MarLs (MarL1 and MarL3, derived from ω-3 docosahexaenoic acid) reverse this impairment. Our published data showed that MarL3 enhances diabetic wound healing and promotes the expression of reparative VEGF, PDGF-BB, and IL10, and the switch to reparative Ms and that it is likely to act via PI3K signaling. MarL3 also promotes wound blood-vessel growth and VEGF formation by endothelial cells. By contrast, MarL1 promotes the production of regenerative growth factor HGF and attenuates M production of pro-inflammatory TNFα. MarL1 also enhances M promoted migration of epithelial cells, fibroblasts, and stem cells. Application of MarL1 to wounds of aged mice improves healing. However, the therapeutic potential of MarLs is limited, because topically applied MarLs are eliminated from wounds within a few hours, whereas wound healing takes many days. Wound healing also involves multiple processes across this long time course, and many of these steps could be promoted by MarLs. In preliminary studies, we obtained sustained release of MarL1 to wounds using MarL1 embedded in amino acid (arginine)-based poly(ester amide) protein-mimic (AA-PEA) microparticles (µPs). AA-PEAs are a new generation of biomaterials that are biocompatible, biodegradable, and non-toxic. The MarL1 embedded in AA-PEA-µPs was more effective than MarL1 alone in promoting wound closure in aging. Our hypothesis is that a sustained release of MarLs to wounds will resolve inflammation and overcome the aging-impairment of healing. Our objective is to develop and assess the ability of our innovative µP-sustained release of MarLs to restore wound healing in the aged. Specific Aim 1. A) Develop the MarL-loaded µPs to control and sustain MarL- release to wounds of aged mice and determine kinetics of MarL release in wounds. B) Determine the optimal sustained MarL release from µPs and administration regimens for resolving inflammation and restoring healing (re-epithelialization, blood vessel regeneration, skin breaking-strength) of aged mice. This project will use µPs- sustained-release MarLs to identify an innovative strategy as well as therapeutic leads to overcome the impairment of healing in non-healing wounds of the elderly. It will also provide a new knowledge about the temporal relationship between the resolution of inflammation and healing of wounds in aging.