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Author: Bekeschus, Sander × End date: 2023 × End date: 2021 × DDC: 540 × Has files: Yes ×

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Now showing 1 - 10 of 21
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    Singlet-Oxygen-Induced Phospholipase A2 Inhibition: A Major Role for Interfacial Tryptophan Dioxidation
    (Weinheim : Wiley-VCH, 2021) Nasri, Zahra; Memari, Seyedali; Wenske, Sebastian; Clemen, Ramona; Martens, Ulrike; Delcea, Mihaela; Bekeschus, Sander; Weltmann, Klaus-Dieter; von Woedtke, Thomas; Wende, Kristian
    Several studies have revealed that various diseases such as cancer have been associated with elevated phospholipase A2 (PLA2) activity. Therefore, the regulation of PLA2 catalytic activity is undoubtedly vital. In this study, effective inactivation of PLA2 due to reactive species produced from cold physical plasma as a source to model oxidative stress is reported. We found singlet oxygen to be the most relevant active agent in PLA2 inhibition. A more detailed analysis of the plasma-treated PLA2 identified tryptophan 128 as a hot spot, rich in double oxidation. The significant dioxidation of this interfacial tryptophan resulted in an N-formylkynurenine product via the oxidative opening of the tryptophan indole ring. Molecular dynamics simulation indicated that the efficient interactions between the tryptophan residue and phospholipids are eliminated following tryptophan dioxidation. As interfacial tryptophan residues are predominantly involved in the attaching of membrane enzymes to the bilayers, tryptophan dioxidation and indole ring opening leads to the loss of essential interactions for enzyme binding and, consequently, enzyme inactivation. © 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH
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    Gas Plasma-Augmented Wound Healing in Animal Models and Veterinary Medicine
    (Basel : MDPI, 2021) Bekeschus, Sander; Kramer, Axel; Schmidt, Anke
    The loss of skin integrity is inevitable in life. Wound healing is a necessary sequence of events to reconstitute the body’s integrity against potentially harmful environmental agents and restore homeostasis. Attempts to improve cutaneous wound healing are therefore as old as humanity itself. Furthermore, nowadays, targeting defective wound healing is of utmost importance in an aging society with underlying diseases such as diabetes and vascular insufficiencies being on the rise. Because chronic wounds’ etiology and specific traits differ, there is widespread polypragmasia in targeting non-healing conditions. Reactive oxygen and nitrogen species (ROS/RNS) are an overarching theme accompanying wound healing and its biological stages. ROS are signaling agents generated by phagocytes to inactivate pathogens. Although ROS/RNS’s central role in the biology of wound healing has long been appreciated, it was only until the recent decade that these agents were explicitly used to target defective wound healing using gas plasma technology. Gas plasma is a physical state of matter and is a partially ionized gas operated at body temperature which generates a plethora of ROS/RNS simultaneously in a spatiotemporally controlled manner. Animal models of wound healing have been vital in driving the development of these wound healing-promoting technologies, and this review summarizes the current knowledge and identifies open ends derived from in vivo wound models under gas plasma therapy. While gas plasma-assisted wound healing in humans has become well established in Europe, veterinary medicine is an emerging field with great potential to improve the lives of suffering animals.
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    Combined toxicity of gas plasma treatment and nanoparticles exposure in melanoma cells in vitro
    (Basel : MDPI, 2021) Bekeschus, Sander
    Despite continuous advances in therapy, cancer remains a deadly disease. Over the past years, gas plasma technology emerged as a novel tool to target tumors, especially skin. Another promising anticancer approach are nanoparticles. Since combination therapies are becoming increas-ingly relevant in oncology, both gas plasma treatment and nanoparticle exposure were combined. A series of nanoparticles were investigated in parallel, namely, silica, silver, iron oxide, cerium oxide, titanium oxide, and iron-doped titanium oxide. For gas plasma treatment, the atmospheric pressure argon plasma jet kINPen was utilized. Using three melanoma cell lines, the two murine non-metastatic B16F0 and metastatic B16F10 cells and the human metastatic B-Raf mutant cell line SK-MEL-28, the combined cytotoxicity of both approaches was identified. The combined cytotoxicity of gas plasma treatment and nanoparticle exposure was consistent across all three cell lines for silica, silver, iron oxide, and cerium oxide. In contrast, for titanium oxide and iron-doped titanium oxide, significantly combined cytotoxicity was only observed in B16F10 cells.
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    Combining Biocompatible and Biodegradable Scaffolds and Cold Atmospheric Plasma for Chronic Wound Regeneration
    (Basel : Molecular Diversity Preservation International (MDPI), 2021) Emmert, Steffen; Pantermehl, Sven; Foth, Aenne; Waletzko-Hellwig, Janine; Hellwig, Georg; Bader, Rainer; Illner, Sabine; Grabow, Niels; Bekeschus, Sander; Weltmann, Klaus-Dieter; Jung, Ole; Boeckmann, Lars
    Skin regeneration is a quite complex process. Epidermal differentiation alone takes about 30 days and is highly regulated. Wounds, especially chronic wounds, affect 2% to 3% of the elderly population and comprise a heterogeneous group of diseases. The prevailing reasons to develop skin wounds include venous and/or arterial circulatory disorders, diabetes, or constant pressure to the skin (decubitus). The hallmarks of modern wound treatment include debridement of dead tissue, disinfection, wound dressings that keep the wound moist but still allow air exchange, and compression bandages. Despite all these efforts there is still a huge treatment resistance and wounds will not heal. This calls for new and more efficient treatment options in combination with novel biocompatible skin scaffolds. Cold atmospheric pressure plasma (CAP) is such an innovative addition to the treatment armamentarium. In one CAP application, antimicrobial effects, wound acidification, enhanced microcirculations and cell stimulation can be achieved. It is evident that CAP treatment, in combination with novel bioengineered, biocompatible and biodegradable electrospun scaffolds, has the potential of fostering wound healing by promoting remodeling and epithelialization along such temporarily applied skin replacement scaffolds.
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    Patient-derived human basal and cutaneous squamous cell carcinoma tissues display apoptosis and immunomodulation following gas plasma exposure with a certified argon jet
    (Basel : Molecular Diversity Preservation International, 2021) Saadati, Fariba; Moritz, Juliane; Berner, Julia; Freund, Eric; Miebach, Lea; Helfrich, Iris; Stoffels, Ingo; Emmert, Steffen; Bekeschus, Sander
    Reactive oxygen species (ROS) have been subject of increasing interest in the pathophysiology and therapy of cancers in recent years. In skin cancer, ROS are involved in UV-induced tumorigenesis and its targeted treatment via, e.g., photodynamic therapy. Another recent technology for topical ROS generation is cold physical plasma, a partially ionized gas expelling dozens of reactive species onto its treatment target. Gas plasma technology is accredited for its wound-healing abilities in Europe, and current clinical evidence suggests that it may have beneficial effects against actinic keratosis. Since the concept of hormesis dictates that low ROS levels perform signaling functions, while high ROS levels cause damage, we investigated herein the antitumor activity of gas plasma in non-melanoma skin cancer. In vitro, gas plasma exposure diminished the metabolic activity, preferentially in squamous cell carcinoma cell (SCC) lines compared to non-malignant HaCaT cells. In patient-derived basal cell carcinoma (BCC) and SCC samples treated with gas plasma ex vivo, increased apoptosis was found in both cancer types. Moreover, the immunomodulatory actions of gas plasma treatment were found affecting, e.g., the expression of CD86 and the number of regulatory T-cells. The supernatants of these ex vivo cultured tumors were quantitatively screened for cytokines, chemokines, and growth factors, identifying CCL5 and GM-CSF, molecules associated with skin cancer metastasis, to be markedly decreased. These findings suggest gas plasma treatment to be an interesting future technology for non-melanoma skin cancer topical therapy.
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    Plasma medical oncology: Immunological interpretation of head and neck squamous cell carcinoma
    (Hoboken, NJ : Wiley Interscience, 2020) Witzke, Katharina; Seebauer, Christian; Jesse, Katja; Kwiatek, Elisa; Berner, Julia; Semmler, Marie‐Luise; Boeckmann, Lars; Emmert, Steffen; Weltmann, Klaus‐Dieter; Metelmann, Hans‐Robert; Bekeschus, Sander
    The prognosis of patients suffering from advanced-stage head and neck squamous cell carcinoma (HNSCC) remains poor. Medical gas plasma therapy receives growing attention as a novel anticancer modality. Our recent prospective observational study on HNSCC patients suffering from contaminated tumor ulcerations without lasting remission after first-line anticancer therapy showed remarkable efficacy of gas plasma treatment, with the ulcerated tumor surface decreasing by up to 80%. However, tumor growth relapsed, and this biphasic response may be a consequence of immunological and molecular changes in the tumor microenvironment that could be caused by (a) immunosuppression, (b) tumor cell adaption, (c) loss of microbe-induced immunostimulation, and/or (d) stromal cell adaption. These considerations may be vital for the design of clinical plasma trials in the future.
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    White paper on plasma for medicine and hygiene: Future in plasma health sciences
    (Hoboken, NJ : Wiley Interscience, 2019) Bekeschus, Sander; Favia, Pietro; Robert, Eric; von Woedtke, Thomas
    Plasma Science and Technology offer their valuable contribution to human health since more than 50 years, after decades of experiences in the field of biomaterials; and more than a decade in using plasmas for therapeutic uses in medicine. Current knowledge as well as key challenges and opportunities for the human health have been intensely discussed during the Future in Plasma Science II (FIPS II) workshop in February 2016 in Greifswald, Germany. This contribution summarizes the major outcomes of the meeting and the current literature and consensus with an emphasis on major challenges in the fields of Plasma Science and Technology for improving human health.
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    Zebrafish larvae as a toxicity model in plasma medicine
    (Hoboken, NJ : Wiley Interscience, 2021) Gandhirajan, Rajesh K.; Endlich, Nicole; Bekeschus, Sander
    Plasma technology has emerged as a promising tool in medicine that, however, requires not only efficacy but also toxicological assessments. Traditional cell culture systems are fast and economical, but they lack in vivo relevance; however, rodent models are highly complex and necessitate extended facilities. Zebrafish larvae bridge this gap, and many larvae can be analyzed in well plates in a single run, giving results in 1–2 days. Using the kINPen, we found plasma exposure to reduce hedging rates and viability in a dose-dependent manner, accompanied with an increase in reactive oxygen species and a decrease of glutathione in plasma-treated fish. Modest growth alterations were also observed. Altogether, zebrafish larvae constitute a fast, reliable, and relevant model for testing the toxicity of plasma sources.
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    A Comparison of Floating-Electrode DBD and kINPen Jet: Plasma Parameters to Achieve Similar Growth Reduction in Colon Cancer Cells Under Standardized Conditions
    (Dordrecht : Springer Science + Business Media B.V., 2017-9-6) Bekeschus, Sander; Lin, Abraham; Fridman, Alexander; Wende, Kristian; Weltmann, Klaus-Dieter; Miller, Vandana
    A comparative study of two plasma sources (floating-electrode dielectric barrier discharge, DBD, Drexel University; atmospheric pressure argon plasma jet, kINPen, INP Greifswald) on cancer cell toxicity was performed. Cell culture protocols, cytotoxicity assays, and procedures for assessment of hydrogen peroxide (H2O2) were standardized between both labs. The inhibitory concentration 50 (IC50) and its corresponding H2O2 deposition was determined for both devices. For the DBD, IC50 and H2O2 generation were largely dependent on the total energy input but not pulsing frequency, treatment time, or total number of cells. DBD cytotoxicity could not be replicated by addition of H2O2 alone and was inhibited by larger amounts of liquid present during the treatment. Jet plasma toxicity depended on peroxide generation as well as total cell number and amount of liquid. Thus, the amount of liquid present during plasma treatment in vitro is key in attenuating short-lived species or other physical effects from plasmas. These in vitro results suggest a role of liquids in or on tissues during plasma treatment in a clinical setting. Additionally, we provide a platform for correlation between different plasma sources for a predefined cellular response.
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    An Innovative Therapeutic Option for the Treatment of Skeletal Sarcomas: Elimination of Osteo- and Ewing’s Sarcoma Cells Using Physical Gas Plasma
    (Basel : Molecular Diversity Preservation International, 2020) Jacoby, Josephine M.; Strakeljahn, Silas; Nitsch, Andreas; Bekeschus, Sander; Hinz, Peter; Mustea, Alexander; Ekkernkamp, Axel; Tzvetkov, Mladen V.; Haralambiev, Lyubomir; Stope, Matthias B.
    Osteosarcoma and Ewing’s sarcoma are the most common malignant bone tumors. Conventional therapies such as polychemotherapy, local surgery, and radiotherapy improve the clinical outcome for patients. However, they are accompanied by acute and chronic side effects that affect the quality of life of patients, motivating novel research lines on therapeutic options for the treatment of sarcomas. Previous experimental work with physical plasma operated at body temperature (cold atmospheric plasma, CAP) demonstrated anti-oncogenic effects on different cancer cell types. This study investigated the anti-cancer effect of CAP on two bone sarcoma entities, osteosarcoma and Ewing’s sarcoma, which were represented by four cell lines (U2-OS, MNNG/HOS, A673, and RD-ES). A time-dependent anti-proliferative effect of CAP on all cell lines was observed. CAP-induced alterations in cell membrane functionality were detected by performing a fluorescein diacetate (FDA) release assay and an ATP release assay. Additionally, modifications of the cell membrane and modifications in the actin cytoskeleton composition were examined using fluorescence microscopy monitoring dextran-uptake assay and G-/F-actin distribution. Furthermore, the CAP-induced induction of apoptosis was determined by TUNEL and active caspases assays. The observations suggest that a single CAP treatment of bone sarcoma cells may have significant anti-oncogenic effects and thus may be a promising extension to existing applications. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.