Delayed graft function (DGF) results from ischemia-reperfusion injury (IRI) and the generation of reactive oxygen species. We hypothesized that NADPH oxidase 2 (Nox2) plays an important role in pathways leading to DGF. We tested this hypothesis in vitro, in an animal model of IRI using wild type and Nox2−/− mice, and in patients with DGF. Under hypoxic conditions, primary tubular epithelial cells from Nox2−/− mice had reduced expression of MMP2, vimentin and HSP27. BUN and creatinine levels were significantly increased in both Nox2−/− and WT mice at 4 weeks and 6 months after IRI, suggesting the development of acute and chronic kidney injury. At 4 weeks, kidney fibrosis (α-SMA, picrosirius) and oxidative stress (dihydroethidine, HNE) were significantly reduced in Nox2−/− mice, confirming the oxidative and pro-fibrotic effects of Nox2. The molecular signature of IRI using genomic analyses demonstrated a significant decline in hypoxia reponse, oxidative stress, fibrosis, and inflammation in Nox2−/− mice. Immunohistochemical analyses of pre-implanatation kidney allograft biopsies from patients with subsequent DGF showed significantly greater Nox2 levels and vascular injury compared with patients without DGF. These studies demonstrate that Nox2 is a modulator of IRI and its absence is associated with reduced inflammation, OS, and fibrosis.
This first report of the large combined experience with DCDD from the Improving DCDD Outcomes in Liver Transplant consortium demonstrates significant differences in IC among centers, the importance of biliary strictures as a risk factor for graft failure, and does not validate other risk factors for IC found in smaller studies.
Background
Electrostimulation (ES) therapy for wound healing is limited in clinical use due to barriers such as cumbersome equipment and intermittent delivery of therapy.
Methods
We adapted a human skin xenograft model that can be used to directly examine the nanogenerator-driven ES (NG-ES) effects on human skin in vivo—an essential translational step toward clinical application of the NG-ES technique for wound healing.
Results
We show that NG-ES leads to rapid wound closure with complete restoration of normal skin architecture within 7 days compared to more than 30 days in the literature. NG-ES accelerates the inflammatory phase of wound healing with more rapid resolution of neutrophils and macrophages and enhances wound bed perfusion with more robust neovascularization.
Conclusion
Our results support the translational evaluation and optimization of the NG-ES technology to deliver convenient, efficient wound healing therapy for use in human wounds.
Graphic abstract
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