Dipartimento di Scienze Biomediche, Chirurgiche e Odontoiatriche, Università degli Studi di Milano, via Pascal 36, 20133, Milano, Italy.
Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135, Torino, Italy.
Eur J Pharmacol. 2022 Sep 15;931:175161. doi: 10.1016/j.ejphar.2022.175161. Epub 2022 Aug 11.
Chronic wounds are associated with inflammation, infections, and hypoxic environment. Macrophages play a crucial role in wound healing removing bacteria and secreting signal molecules to coordinate tissue repair. Recently, dextran-shelled Oxygen-Loaded NanoDroplets (OLNDs) have been proposed as new tools to counteract hypoxia in chronic wounds. Here we investigated the effects of OLNDs on Enterococcus faecalis (E. faecalis) killing and the secretion of inflammatory and angiogenic factors by murine (BMDM) and human (dTHP-1, differentiated THP-1) macrophages, in normoxia and hypoxia. Both OLNDs and Oxygen-Free NanoDroplets (OFNDs) significantly increased reactive oxygen species production by BMDM in normoxia (4.1 and 4 fold increase by 10% OLNDs and OFNDs, respectively, after 120 min) and hypoxia (3.8 and 4 fold increase by 10% OLNDs and OFNDs respectively) but not by dTHP-1. Moreover, only OLNDs induced nitric oxide secretion by BMDM in normoxia. Consequently, both nanodroplets improved E. faecalis killing by BMDM in normoxia (% of killing OLNDs = 44.2%; p < 0.01; OFNDs = 41.4%; p < 0.05) and hypoxia (% of killing OLNDs = 43.1%; p < 0.01; OFNDs = 37.7%; p < 0.05), while dTHP-1-mediated killing was not affected. The secretion of the inflammatory cytokines (TNFα, IL-6, IL-1β) induced by E. faecalis infection in dTHP-1 was reduced by both types of nanodroplets, suggesting a novel anti-inflammatory activity of the dextran shell. Instead, the increase of VEGF induced by hypoxia was reduced only by OLNDs. These data provide new knowledge on the effects of OLNDs as innovative adjuvant in chronic wounds healing promoting bacterial killing and reducing inflammation.
慢性伤口与炎症、感染和缺氧环境有关。巨噬细胞在伤口愈合中起着至关重要的作用，它们可以清除细菌并分泌信号分子来协调组织修复。最近，葡聚糖壳载氧纳米液滴（OLNDs）被提议作为对抗慢性伤口缺氧的新工具。在这里，我们研究了 OLNDs 在正常氧和缺氧条件下对粪肠球菌（E. faecalis）杀伤作用和炎症及血管生成因子分泌的影响，使用了小鼠（BMDM）和人（dTHP-1，分化的 THP-1）巨噬细胞。OLNDs 和无氧气纳米液滴（OFNDs）在正常氧条件下（120 分钟后，10% OLNDs 和 OFNDs 分别使 BMDM 中活性氧的产生增加了 4.1 和 4 倍）和缺氧条件下（10% OLNDs 和 OFNDs 分别使 BMDM 中活性氧的产生增加了 3.8 和 4 倍）均显著增加了 BMDM 中活性氧的产生，但在 dTHP-1 中则没有。此外，只有 OLNDs 在正常氧条件下诱导了 BMDM 一氧化氮的分泌。因此，两种纳米液滴均提高了 BMDM 在正常氧（OLNDs%杀伤率=44.2%；p<0.01；OFNDs%杀伤率=41.4%；p<0.05）和缺氧（OLNDs%杀伤率=43.1%；p<0.01；OFNDs%杀伤率=37.7%；p<0.05）条件下对粪肠球菌的杀伤作用，而 dTHP-1 介导的杀伤作用则不受影响。OLNDs 和 OFNDs 均降低了粪肠球菌感染诱导的人源 dTHP-1 中促炎细胞因子（TNFα、IL-6、IL-1β）的分泌，提示葡聚糖壳具有新的抗炎活性。相反，仅 OLNDs 降低了缺氧诱导的 VEGF 增加。这些数据为 OLNDs 作为慢性伤口愈合的新型佐剂提供了新的知识，促进了细菌杀伤和减少炎症。
