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    Medical gas plasma-stimulated wound healing: Evidence and mechanisms
    (Amsterdam [u.a.] : Elsevier, 2021) Bekeschus, Sander; von Woedtke, Thomas; Emmert, Steffen; Schmidt, Anke
    Defective wound healing poses a significant burden on patients and healthcare systems. In recent years, a novel reactive oxygen and nitrogen species (ROS/RNS) based therapy has received considerable attention among dermatologists for targeting chronic wounds. The multifaceted ROS/RNS are generated using gas plasma technology, a partially ionized gas operated at body temperature. This review integrates preclinical and clinical evidence into a set of working hypotheses mainly based on redox processes aiding in elucidating the mechanisms of action and optimizing gas plasmas for therapeutic purposes. These hypotheses include increased wound tissue oxygenation and vascularization, amplified apoptosis of senescent cells, redox signaling, and augmented microbial inactivation. Instead of a dominant role of a single effector, it is proposed that all mechanisms act in concert in gas plasma-stimulated healing, rationalizing the use of this technology in therapy-resistant wounds. Finally, addressable current challenges and future concepts are outlined, which may further promote the clinical utilization, efficacy, and safety of gas plasma technology in wound care in the future.
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    Medical gas plasma augments bladder cancer cell toxicity in preclinical models and patient-derived tumor tissues
    (Amsterdam [u.a.] : Elsevier, 2022) Gelbrich, Nadine; Miebach, Lea; Berner, Julia; Freund, Eric; Saadati, Fariba; Schmidt, Anke; Stope, Matthias; Zimmermann, Uwe; Burchardt, Martin; Bekeschus, Sander
    Introduction: Medical gas plasma therapy has been successfully applied to several types of cancer in preclinical models. First palliative tumor patients suffering from advanced head and neck cancer benefited from this novel therapeutic modality. The gas plasma-induced biological effects of reactive oxygen and nitrogen species (ROS/RNS) generated in the plasma gas phase result in oxidation-induced lethal damage to tumor cells. Objectives: This study aimed to verify these anti-tumor effects of gas plasma exposure on urinary bladder cancer. Methods: 2D cell culture models, 3D tumor spheroids, 3D vascularized tumors grown on the chicken chorion-allantois-membrane (CAM) in ovo, and patient-derived primary cancer tissue gas plasma-treated ex vivo were used. Results: Gas plasma treatment led to oxidation, growth retardation, motility inhibition, and cell death in 2D and 3D tumor models. A marked decline in tumor growth was also observed in the tumors grown in ovo. In addition, results of gas plasma treatment on primary urothelial carcinoma tissues ex vivo highlighted the selective tumor-toxic effects as non-malignant tissue exposed to gas plasma was less affected. Whole-transcriptome gene expression analysis revealed downregulation of tumor-promoting fibroblast growth factor receptor 3 (FGFR3) accompanied by upregulation of apoptosis-inducing factor 2 (AIFm2), which plays a central role in caspase-independent cell death signaling. Conclusion: Gas plasma treatment induced cytotoxicity in patient-derived cancer tissue and slowed tumor growth in an organoid model of urinary bladder carcinoma, along with less severe effects in non-malignant tissues. Studies on the potential clinical benefits of this local and safe ROS therapy are awaited.
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    Gas plasma-spurred wound healing is accompanied by regulation of focal adhesion, matrix remodeling, and tissue oxygenation
    (Amsterdam [u.a.] : Elsevier, 2021) Schmidt, Anke; Liebelt, Grit; Nießner, Felix; von Woedtke, Thomas; Bekeschus, Sander
    In response to injury, efficient migration of skin cells to rapidly close the wound and restore barrier function requires a range of coordinated processes in cell spreading and migration. Gas plasma technology produces therapeutic reactive species that promote skin regeneration by driving proliferation and angiogenesis. However, the underlying molecular mechanisms regulating gas plasma-aided cell adhesion and matrix remodeling essential for wound closure remain elusive. Here, we combined in vitro analyses in primary dermal fibroblasts isolated from murine skin with in vivo studies in a murine wound model to demonstrate that gas plasma treatment changed phosphorylation of signaling molecules such as focal adhesion kinase and paxillin α in adhesion-associated complexes. In addition to cell spreading and migration, gas plasma exposure affected cell surface adhesion receptors (e.g., integrinα5β1, syndecan 4), structural proteins (e.g., vinculin, talin, actin), and transcription of genes associated with differentiation markers of fibroblasts-to-myofibroblasts and epithelial-to-mesenchymal transition, cellular protrusions, fibronectin fibrillogenesis, matrix metabolism, and matrix metalloproteinase activity. Finally, we documented that gas plasma exposure increased tissue oxygenation and skin perfusion during ROS-driven wound healing. Altogether, these results provide critical insights into the molecular machinery of gas plasma-assisted wound healing mechanisms.