Stephanie Arndt

The occurrence of contact lens complications caused by inadequate cleaning of the lenses using “All-in-One” contact lens cleaning solutions (CLCSs) represents a medically relevant problem worldwide. This study explores the potential of cold atmospheric plasma (CAP) to enhance the efficacy of CLCSs and address complications from inadequate lens hygiene. It was examined whether exposure to CAP for 1–24 h could boost the antibacterial effects of CLCSs and other solutions, including Milli-Q water (M-QW), physiological saline (NaCl), and Dulbecco’s Phosphate Buffered Saline (DPBS). Additionally, the stability of reactive oxygen and nitrogen species (RONS) and their impact on pH immediately after treatment and over 1–4 weeks was assessed. Furthermore, the cleaning efficacy of plasma-activated solutions (PASs) was tested on lipid-coated silicone hydrogel lenses. Results showed that CAP increased RONS concentrations immediately, with elevated levels persisting over time. While no significant improved antibacterial effect was observed against Escherichia coli in CLCSs, CAP treatment generated disinfectant properties in M-QW and NaCl solutions. Importantly, CAP-treated CLCSs significantly improved the cleaning performance on lipid-coated lenses, though M-QW’s cleaning ability worsened post-treatment. pH measurements indicated notable decreases in M-QW and NaCl after CAP, whereas buffered solutions like CLCSs and DPBS remained stable. Overall, CAP demonstrates promise for contact lens disinfection and surface modification; however, further research and pre-clinical trials are necessary before clinical application in ophthalmology.

Cold atmospheric plasma (CAP) devices produce reactive oxygen and reactive nitrogen species, which have antimicrobial and antiviral effects, while also affecting the molecular and cellular processes in eukaryotic cells. This study investigates the effects of CAP treatment on immune responses and long-term organism health in the upper respiratory tract (URT). Using a surface-microdischarge-based plasma intensive care (PIC) device from terraplasma medical GmbH, 129Sv/Ev wildtype mice were exposed to short (single 10 min session), long (five 10 min sessions), and recovery-phase treatments (five 10 min sessions; 7 days of recovery). Bronchoalveolar lavage fluid was examined by cytospin, fluorescence-activated cell sorting, and mRNA expression analysis. Lung tissue was analyzed for morphological changes (H&E), DNA damage (γH2AX), apoptosis (TUNEL), immune cell marker alterations (CD45, Ly-6G, CD68, CD3, MCC), and fibrosis (NE). Results showed that PIC treatment increased the number of apoptotic cells and activated immune markers, such as IFN-γ, IL-6, and TNF-α, in the lungs, especially after multiple treatments. These effects largely reversed after a 7-day regeneration period. Importantly, no DNA damage or morphological lung alterations were observed across groups. The findings suggest that PIC treatment in the URT induces transient immune activation without causing tissue damage, but caution is advised for patients with cytokine release syndrome or macrophage activation syndrome due to potential cytokine surges.

Background/Objectives: Actinic keratosis (AK) occurs on sun-damaged skin and is considered a precursor to squamous cell carcinoma (SCC). Photodynamic therapy (PDT), using 5-aminolevulinic acid (ALA) and red light, is a common treatment for AK. However, its clinical efficacy for invasive tumors such as SCC is limited by the poor penetration and distribution of the photosensitizer. Cold atmospheric plasma (CAP), a partially ionized gas, increases skin permeability and exhibits anti-cancer properties through the generation of reactive oxygen species (ROS). In a previous study, CAP showed promising synergistic effects when combined with ALA-PDT for the treatment of SCC cells in vitro. The present study investigated the effects of combining CAP with ALA-PDT on cutaneous AK and SCC induced by ultraviolet B (UV-B) irradiation in SKH1 hairless mice. Methods: We compared various application sequences (CAP-ALA–red light, ALA–red light–CAP, and ALA-CAP–red light) against conventional ALA-PDT using visual, histological, and molecular assessments of the affected skin. Results: The results demonstrated that combined treatments strongly inhibited the growth of UV-B-induced skin lesions. TUNEL staining revealed increased apoptosis following both single and combined therapies, while Ki-67 staining indicated reduced keratinocyte proliferation and diminished DNA damage in treated areas. mRNA expression analysis showed the upregulation of apoptosis-related genes (p16^INK4a, p21^CIP1) alongside enhanced anti-tumor immune responses (IL-6, IL-8) in the affected tissue samples. Notably, the combined treatment enhances the therapeutic effect, whereas the sequence of application does not seem to be relevant for therapeutic efficacy in vivo. Conclusions: Overall, these results suggest that CAP may enhance the anti-tumor effect of conventional ALA-PDT, supporting previous findings on SCC cells.

Cold atmospheric plasma (CAP) has antimicrobial properties and is also known to stimulate the immune system. These properties could be useful for the development of a novel therapeutic or preventive strategy against respiratory infections in the upper respiratory tract (URT) such as ventilator-associated pneumonia (VAP) without inducing an immune overreaction. This study investigated the cellular responses of polymorphonuclear neutrophils (PMNs) after exposure to CAP in a three-dimensional (3D) model of the URT. In vitro experiments were conducted using PMNs isolated from human blood to assess cell migration, intracellular production of reactive oxygen species (ROS), NETosis, surface marker expression (CD11b, CD62L, and CD66b), and cell death with live cell imaging and flow cytometry. CAP was applied for 5 min using two distinct modalities: pressurized air plasma with a plasma intensive care (PIC) device and nebulized air plasma (NP) with a new humidity resistent surface microdischarge (SMD) plasma source, both developed by Terraplasma Medical GmbH. There were no significant signs of cell damage or overstimulation with either device under the conditions tested. However, the NP device caused milder effects on PMN functionality compared to the PIC device, but also demonstrated reduced antibacterial efficacy and reactive oxygen/nitrogen species (RONS) production, as analyzed with colorimetric/fluorimetric assay kits. These findings highlight a trade-off between the two CAP modalities, each with distinct advantages and limitations. Further studies are necessary to investigate these effects in the clinical setting and evaluate the long-term safety and efficacy of CAP treatment in the URT.

Actinic keratosis (AK) is characterized by a reddish or occasionally skin-toned rough patch on sun-damaged skin, and it is regarded as a precursor to squamous cell carcinoma (SCC). Photodynamic therapy (PDT), utilizing 5-aminolevulinic acid (ALA) along with red light, is a recognized treatment option for AK that is limited by the penetration depth of light and the distribution of the photosensitizer into the skin. Cold atmospheric plasma (CAP) is a partially ionized gas with permeability-enhancing and anti-cancer properties. This study analyzed, in vitro, whether a combined treatment of CAP and ALA-PDT may improve the efficacy of the treatment. In addition, the effect of the application sequence of ALA and CAP was investigated using in vitro assays and the molecular characterization of human oral SCC cell lines (SCC-9, SCC-15, SCC-111), human cutaneous SCC cell lines (SCL-1, SCL-2, A431), and normal human epidermal keratinocytes (HEKn). The anti-tumor effect was determined by migration, invasion, and apoptosis assays and supported the improved efficacy of ALA-PDT in combination with CAP. However, the application sequence ALA-CAP–red light seems to be more efficacious than CAP-ALA–red light, which is probably due to increased intracellular ROS levels when ALA is applied first, followed by CAP and red light treatment. Furthermore, the expression of apoptosis- and senescence-related molecules (caspase-3, -6, -9, p16^INK4a, p21^CIP1) was increased, and different genes of the junctional network (ZO-1, CX31, CLDN1, CTNNB1) were induced after the combined treatment of CAP plus ALA-PDT. HEKn, however, were much less affected than SCC cells. Overall, the results show that CAP may improve the anti-tumor effects of conventional ALA-PDT on SCC cells. Whether this combined application is successful in treating AK in vivo has to be carefully examined in follow-up studies.

Background: The application of normo- and hyperbaric O₂ is a common therapy option in various disease patterns. Thereby, the applied O₂ affects the whole body, including the blood and its components. This study investigates influences of pressure and oxygen fraction on human blood plasma, nutrient media, and the functions of neutrophil granulocytes (PMNs). Methods: Neutrophil migration, reactive oxygen species (ROS) production, and NETosis were examined by live cell imaging. The treatment of various matrices (Roswell Park Memorial Institute 1640 medium, Dulbecco’s Modified Eagle’s Medium, H₂O, human plasma, and isolated PMNs) with hyperbaric oxygen (HBO) was performed. In addition, the expression of different neutrophil surface epitopes (CD11b, CD62L, CD66b) and the oxidative burst were investigated by flow cytometry (FACS). The application of cold atmospheric plasma (CAP) to normoxic and normobaric culture media served as a positive control. Soluble reaction products such as H₂O₂, reactive nitrogen species (RNS: NO₂⁻ and NO₃⁻), and ROS-dependent dihydrorhodamine oxidation were quantified by fluoro- and colorimetric assay kits. Results: Under normobaric normoxia, PMNs migrate slower and shorter in comparison with normobaric hyper- or hypoxic conditions and hyperbaric hyperoxia. The pressure component has less effect on the migration behavior of PMNs than the O₂ concentration. Individual PMN cells produce prolonged ROS at normoxic conditions. PMNs showed increased expression of CD11b in normobaric normoxia, lower expression of CD62L in normobaric normoxia, and lower expression of CD66b after HBO and CAP treatment. Treatment with CAP increased the amount of ROS and RNS in common culture media. Conclusions: Hyperbaric and normobaric O₂ influences neutrophil functionality and surface epitopes in a measurable way, which may have an impact on disorders with neutrophil involvement. In the context of hyperbaric experiments, especially high amounts of H₂O₂ in RPMI after hyperbaric oxygen should be taken into account. Therefore, our data support a critical indication for the use of normobaric and hyperbaric oxygen and conscientious and careful handling of oxygen in everyday clinical practice.

Cold atmospheric plasma (CAP) devices generate reactive oxygen and nitrogen species, have antimicrobial and antiviral properties, but also affect the molecular and cellular mechanisms of eukaryotic cells. The aim of this study is to investigate CAP treatment in the upper respiratory tract (URT) to reduce the incidence of ventilator-associated bacterial pneumonia (especially superinfections with multi-resistant pathogens) or viral infections (e.g., COVID-19). For this purpose, the surface-microdischarge-based plasma intensive care (PIC) device was developed by terraplasma medical GmbH. This study analyzes the safety aspects using in vitro assays and molecular characterization of human oral keratinocytes (hOK), human bronchial–tracheal epithelial cells (hBTE), and human lung fibroblasts (hLF). A 5 min CAP treatment with the PIC device at the “throat” and “subglottis” positions in the URT model did not show any significant differences from the untreated control (ctrl.) and the corresponding pressurized air (PA) treatment in terms of cell morphology, viability, apoptosis, DNA damage, and migration. However, pro-inflammatory cytokines (MCP-1, IL-6, and TNFα) were induced in hBTE and hOK cells and profibrotic molecules (collagen-I, FKBP10, and αSMA) in hLF at the mRNA level. The use of CAP in the oropharynx may make an important contribution to the recovery of intensive care patients. The results indicate that a 5 min CAP treatment in the URT with the PIC device does not cause any cell damage. The extent to which immune cell activation is induced and whether it has long-term effects on the organism need to be carefully examined in follow-up studies in vivo.

Cold atmospheric plasma (CAP) describes a partially ionized gas carrying large amounts of reactive oxygen (ROS) and nitrogen species (RNS). Numerous studies reported strong antitumor activity of CAP, thus rendering it a promising approach for tumor therapy. Although several cellular mechanisms of its cytotoxicity were identified in recent years, the exact molecular effects and contributing signaling pathways are yet to be discovered. We discovered a strong activation of unfolded protein response (UPR) after CAP treatment with increased C/EBP homologous protein (CHOP) expression, which was mainly caused by protein misfolding and calcium loss in the endoplasmic reticulum. In addition, both ceramide level and ceramide metabolism were reduced after CAP treatment, which was then linked to the UPR activation. Pharmacological inhibition of ceramide metabolism resulted in sensitization of melanoma cells for CAP both in vitro and ex vivo. This study identified a novel mechanism of CAP-induced apoptosis in melanoma cells and thereby contributes to its potential application in tumor therapy.

Background: Polymorphous light eruption (PLE) is a common, immunologically mediated, photosensitive skin disease. After ultraviolet‐B (UV‐B) irradiation, patients with PLE show reduced Langerhans cell (LC) depletion in the epidermis, which results in a non‐suppressive microenvironment in the skin. Interestingly, severe acute graft‐versus‐host disease (aGvHD) occurred in stem cell transplanted patients that showed no or incomplete depletion of LCs after UVB irradiation. Genetic variation in nucleotide‐binding oligomerization domain 2 (NOD‐2) and toll‐like receptor 5 (TLR‐5) genes also confers susceptibility to aGvHD.Objectives: We hypothesized that PLE is associated with genetic variation in the NOD‐2 and TLR‐5 genes.Methods: We investigated single‐nucleotid polymorphisms (SNPs) of NOD‐2 (R702W, G908R, 3020Cins) and TLR‐5 (A592S, P616L, N392STOP) in skin biopsies of patients with PLE (n = 143) and in healthy controls (n = 104) using restriction fragment length polymorphism analysis.Results: The frequency of NOD‐2 alleles with the SNP R702W was significantly higher in PLE than in controls (31.8% vs. 6.3%; P < 0.0001), and homozygous carriers of this mutation were more common in PLE (27.9% vs. 0%; P < 0.0001). For SNP 3020Cins, the allele frequency (7.3% vs. 0.7%; P = 0.0025) and the number of heterozygotes (14.7% vs. 1.3%; P = 0.0019) were higher in PLE. The frequency of alleles with the N392STOP SNP of the TLR5 gene, which is associated with a truncated, non‐functional receptor, was significantly higher in PLE (21% vs. 5%; 7% vs. 1% homozygotes, 28% vs. 8% heterozygotes; P < 0.0001). The other SNPs did not differ significantly.Conclusions: This study yielded a high frequency of functional SNPs in the NOD‐2 and TLR‐5 genes in PLE. The same SNPs are associated with aGvHD and there are similarities in the reaction of LCs after UVB irradiation between aGvHD and PLE. This leads to the hypothesis that patients with PLE may be more susceptible to developing GvHD after stem cell transplantation, an assumption that needs to be investigated further.

Cold Atmospheric Plasma (CAP) has shown promising results in the treatment of various skin diseases. The therapeutic effect of CAP on localized scleroderma (LS), however, has not yet been evaluated. We investigated the effects of CAP on LS by comparing human normal fibroblasts (hNF), human TGF-β-activated fibroblasts (hAF), and human localized scleroderma-derived fibroblasts (hLSF) after direct CAP treatment, co-cultured with plasma-treated human epidermal keratinocytes (hEK) and with an experimental murine model of scleroderma. In hAF and hLSF, 2 min CAP treatment with the MicroPlaSterβ^® plasma torch did not affect pro-fibrotic gene expression of alpha smooth muscle actin, fibroblast activating protein, and collagen type I, however, it promoted re-expression of matrix metalloproteinase 1. Functionally, CAP treatment reduced cell migration and stress fiber formation in hAF and hLSF. The relevance of CAP treatment was confirmed in an in vivo model of bleomycin-induced dermal fibrosis. In this model, CAP-treated mice showed significantly reduced dermal thickness and collagen deposition as well as a decrease in both alpha smooth muscle actin-positive myofibroblasts and CD68-positive macrophages in the affected skin in comparison to untreated fibrotic tissue. In conclusion, this study provides the first evidence for the successful use of CAP for treating LS and may be the basis for clinical trials including patients with LS.