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Author: Bekeschus, Sander × Publisher: Amsterdam [u.a.] : Elsevier × Subject: Plasma medicine ×

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Now showing 1 - 5 of 5
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    xCT (SLC7A11) expression confers intrinsic resistance to physical plasma treatment in tumor cells
    (Amsterdam [u.a.] : Elsevier, 2020) Bekeschus, Sander; Eisenmann, Sebastian; Sagwal, Sanjeev Kumar; Bodnar, Yana; Moritz, Juliane; Poschkamp, Broder; Stoffels, Ingo; Emmert, Steffen; Madesh, Muniswamy; Weltmann, Klaus-Dieter; von Woedtke, Thomas; Gandhirajan, Rajesh Kumar
    Cold physical plasma is a partially ionized gas investigated as a new anticancer tool in selectively targeting cancer cells in monotherapy or in combination with therapeutic agents. Here, we investigated the intrinsic resistance mechanisms of tumor cells towards physical plasma treatment. When analyzing the dose-response relationship to cold plasma-derived oxidants in 11 human cancer cell lines, we identified four 'resistant' and seven 'sensitive' cell lines. We observed stable intracellular glutathione levels following plasma treatment only in the 'resistant' cell lines indicative of altered antioxidant mechanisms. Assessment of proteins involved in GSH metabolism revealed cystine-glutamate antiporter xCT (SLC7A11) to be significantly more abundant in the 'resistant' cell lines as compared to 'sensitive' cell lines. This decisive role of xCT was confirmed by pharmacological and genetic inhibition, followed by cold physical plasma treatment. Finally, microscopy analysis of ex vivo plasma-treated human melanoma punch biopsies suggested a correlation between apoptosis and basal xCT protein abundance. Taken together, our results demonstrate that xCT holds the potential as a biomarker predicting the sensitivity of tumor cells towards plasma treatment.
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    Can the effect of cold physical plasma-derived oxidants be transported via thiol group oxidation?
    (Amsterdam [u.a.] : Elsevier, 2019) Heusler, Thea; Bruno, Giuliana; Bekeschus, Sander; Lackmann, Jan-Wilm; Woedtke, Thomas von; Wende, Kristian
    Purpose: Intra- and intercellular redox-signaling processes where found responsible in various physiological and pathological processes with cellular thiol groups as important signal transducers. Using cold atmospheric plasma (CAP), a similar oxidation pattern of thiol groups can be achieved. Hence, it must be clarified which role extracellular thiol groups play in mediating CAP effects and whether or not the effects of short-lived reactive species can be preserved in a molecule like cysteine. Methods: Physiological buffer solutions containing the amino acid cysteine were treated by an MHz argon plasma jet with molecular gas admixtures (kINPen) and transferred to cultured human keratinocytes. Cell proliferation, migratory activity, and metabolism were investigated. High-resolution mass spectrometry was used to estimate the impact of plasma generated species on thiol groups. Results: While treated physiologic cysteine concentrations showed no impact on cell behavior, artificially high concentrations decreased proliferation, migration and lactate secretion. GSH levels inside cells were stabilized. Conclusion: Extracellular thiol groups scavenge plasma-generated species and form a multitude of covalent modifications. Unexpectedly, human keratinocytes show only small functional consequences for treated physiologic cysteine concentrations. Results for high concentrated cysteine solutions indicate an improved cytostatic/cytotoxic impact by plasma treatment suggesting a potential application as a “preserving agent” of the chemical energy of plasma-derived species. © 2019 The Authors
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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.
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    Platelets are key in cold physical plasma-facilitated blood coagulation in mice
    (Amsterdam [u.a.] : Elsevier, 2017) Bekeschus, Sander; Brüggemeier, Janik; Hackbarth, Christine; Woedtke, Thomas von; Partecke, Lars-Ivo; van der Linde, Julia
    Purpose: Surgical interventions inevitably lead to destruction of blood vessels. This is especially dangerous in anticoagulated patients. Electrocauterization is a frequently used technique to seal incised tissue. However, leading to a superficial layer of necrotic tissue, the treated area evolves a high vulnerability to contact, making it prone to detachment. As a result, dangerous postoperative bleeding may occur. Cold physical plasma was previously suggested as a pro-coagulant treatment method. It mainly acts by expelling a delicate mixture of oxidants. We therefore tested the suitability of an atmospheric pressure plasma jet (kINPen MED) as a new medical device for sufficient blood coagulation in a murine model of liver incision. Methods: Plasma treatment of murine blood ex vivo induced sufficient coagula. This effect did not affect any tested parameter of plasmatic coagulation cascade, suggesting the mechanism to be related to cellular coagulation. Indeed, isolated platelets were significantly activated following exposure to plasma, although this effect was less pronounced in whole blood. To analyze the biological effect of plasma-on blood coagulation in vivo, mice were anticoagulated (clopidogrel inhibiting cellular and rivaroxaban inhibiting plasmatic hemostasis) or received vehicle only. Afterwards, a partial resection of the left lateral liver lobe was performed. The quantification of the blood loss after liver incision followed by treatment with kINPen MED plasma or electrocauterization revealed a similar and significant hemostatic performance in native and rivaroxaban but not clopidogrel-treated animals compared to argon gas-treated controls. In contrast to electrocauterization, kINPen MED plasma treatment did not cause necrotic cell layers. Conclusion: Our results propose a prime importance of platelets in cold physical plasma-mediated hemostasis and suggest a clinical benefit of kINPen MED plasma treatment as coagulation device in liver surgery.
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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.