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Plasma-derived reactive species shape a differentiation profile in human monocytes
Background: Monocyte-derived macrophages are key regulators and producers of reactive oxygen and nitrogen species (ROS/RNS). Pre-clinical and clinical studies suggest that cold physical plasma may be beneficial in the treatment of inflammatory conditions via the release of ROS/RNS. However, it is unknown how plasma treatment affects monocytes and their differentiation profile. Methods: Naïve or phorbol-12-myristate-13-acetate (PMA)-pulsed THP-1 monocytes were exposed to cold physical plasma. The cells were analyzed regarding their metabolic activity as well as flow cytometry (analysis of viability, oxidation, surface marker expression and cytokine secretion) and high content imaging (quantitative analysis of morphology. Results: The plasma treatment affected THP-1 metabolisms, viability, and morphology. Furthermore, a significant modulation CD55, CD69, CD271 surface-expression and increase of inflammatory IL1β, IL6, IL8, and MCP1 secretion was observed upon plasma treatment. Distinct phenotypical changes in THP-1 cells arguing for a differentiation profile were validated in primary monocytes from donor blood. As a functional outcome, plasma-treated monocytes decreased the viability of co-cultured melanoma cells to a greater extent than their non-treated counterparts. Conclusions: Our results suggest plasma-derived ROS/RNS shaped a differentiation profile in human monocytes as evidenced by their increased inflammatory profile (surface marker and cytokines) as well as functional outcome (tumor toxicity). © 2019 by the authors.
Risk assessment of a cold argon plasma jet in respect to its mutagenicity
Cold atmospheric pressure plasmas represent a favorable option for the treatment of heat sensitive materials and human or animal tissue. Beneficial effects have been documented in a variety of medical conditions, e.g., in the treatment of chronic wounds. It is assumed that the main mechanism of the plasma’s efficacy is mediated by a stimulating dissipation of energy via radiation and/or chemical energy. Although no evidence on undesired side effects of a plasma treatment has yet been presented, skepticism toward the safety of the exposure to plasma is present. However, only little data regarding the mutagenic potential of this new treatment option is available. Accordingly, we investigated the mutagenic potential of an argon plasma jet (kinpen) using different testing systems in accordance with ISO norms and multiple cell lines: a HPRT1 mutation assay, a micronucleus formation assay, and a colony formation assay. Moderate plasma treatment up to 180 s did not increase genotoxicity in any assay or cell type investigated. We conclude that treatment with the argon plasma jet kinpen did not display a mutagenic potential under the test conditions applied and may from this perspective be regarded as safe for the use in biomedical applications.