Refine
Document Type
- Article (46)
- Doctoral Thesis (1)
Language
- English (47)
Has Fulltext
- yes (47)
Is part of the Bibliography
- no (47)
Keywords
- - (37)
- plasma medicine (25)
- reactive oxygen species (16)
- ROS (14)
- cold physical plasma (11)
- kINPen (8)
- reactive oxygen and nitrogen species (7)
- cold atmospheric pressure plasma (5)
- oncology (5)
- CAP (4)
Institute
- Klinik und Poliklinik für Chirurgie Abt. für Viszeral-, Thorax- und Gefäßchirurgie (11)
- Klinik und Poliklinik für Mund-, Kiefer- und Gesichtschirurgie/Plastische Operationen (10)
- Klinik und Poliklinik für Chirurgie Abt. für Unfall- und Wiederherstellungschirurgie (7)
- Institut für Hygiene und Umweltmedizin (5)
- Klinik und Poliklinik für Orthopädie und Orthopädische Chirurgie (3)
- Klinik und Poliklinik für Urologie (3)
- Abteilung für Mikrobiologie und Molekularbiologie (2)
- Institut für Humangenetik (2)
- Institut für Immunologie u. Transfusionsmedizin - Abteilung Immunologie (1)
- Institut für Mikrobiologie - Abteilung für Genetik & Biochemie (1)
- Institut für Pharmakologie (1)
- Institut für Physik (1)
- Interfakultäres Institut für Genetik und Funktionelle Genomforschung (UMG) (1)
- Klinik für Herz-, Thorax- und Gefäßchirurgie - Klinikum Karlsburg (1)
- Klinik und Poliklinik für Neurochirurgie (1)
Publisher
Because of its antimicrobial properties, nonthermal plasma could serve as an alternative to chemical antisepsis in wound treatment. Therefore, this study investigated the inactivation of biofilm-embedded Pseudomonas aeruginosa SG81 by a surface barrier-discharged (SBD) plasma for 30, 60, 150 and 300 s. In order to optimize the efficacy of the plasma, different carrier gases (argon, argon admixed with 1% oxygen, and argon with increased humidity up to approx. 80%) were tested and compared against 0.1% chlorhexidine digluconate (CHG) exposure for 600 s. The antimicrobial efficacy was determined by calculating the difference between the numbers of colony-forming units (CFU) of treated and untreated biofilms. Living bacteria were distinguished from dead by fluorescent staining and confocal laser scanning microscopy. Both SBD plasmas and CHG showed significant antimicrobial effects compared to the untreated control. However, plasma treatment led to a higher antimicrobial reduction (argon plasma 4.9 log<sub>10</sub> CFU/cm<sup>2</sup>, argon with admixed oxygen 3 log<sub>10</sub> CFU/cm<sup>2</sup>, and with increased gas humidity 2.7 log<sub>10</sub> CFU/cm<sup>2</sup> after 300 s) compared to CHG. In conclusion, SBD plasma is suitable as an alternative to CHG for inactivation of Pseudomonas aeruginosa embedded in biofilm. Further development of SBD plasma sources and research on the role of carrier gases and humidity may allow their clinical application for wound management in the future.
Non-healing wounds pose a major burden to patients and health care systems alike. These wounds are chronically stuck in the inflammatory phase of the healing process without transitioning to the proliferative phase. They are also characterized by the excessive presence of leukocytes which are assumed to provoke the persistent inflammation observed in pathological wound healing. Recent studies suggested a beneficial role of cold physical plasma in the treatment of chronic wounds. Hence, it was the central question, whether exposure to cold physical plasma would affect the viability and/or function of human leukocytes. Cold plasma displays various properties of which the generation of reactive molecules, such as reactive oxygen and nitrogen species (ROS/RNS), where found to be central in mediating redox changes in leukocytes. Oxidative stress was present especially in lymphocytes that readily underwent apoptosis after exposure to plasma. This was largely a direct consequence of plasma-generated hydrogen peroxide but not superoxide or RNS. Amount of apoptosis was comparable among several lymphocyte subpopulations, with the wound healing-relevant γδ T cells being least affected. Lymphocyte apoptosis was accompanied by mitochondrial membrane depolarization, caspase 3 activation, DNA fragmentation, and phosphatidylserine exposure. These results are in line with previous characterizations of the intrinsic apoptotic pathway in redox biology, and suggest that plasma-induced apoptosis was not mediated by alternative molecular mechanisms. An important immune response mechanism, the proliferation of lymphocytes, was not interrupted in plasma-treated but non-apoptotic cells. In wounds, a central role of leukocytes is to orchestrate the healing response via the release of small communication molecules called cytokines. Non-healing wounds are associated with elevated amounts of pro-inflammatory IL-1β, IL-6, and TNFα, and plasma-treatment of leukocytes strongly decreased their concentrations. At the same time, the expression of anti inflammatory cytokines (IL-10, TGFβ) was markedly increased. The pro inflammatory chemokine IL-8 was the only molecule to be significantly increased in supernatants of plasma-treated cells. IL-8 is the major chemo-attractant for neutrophil granulocytes. Neutrophils are frequently associated with non-healing wounds. These professional phagocytes are the first to migrate to the site of injury where they inactivate invading pathogens by various mechanisms. Importantly, highly relevant effector functions remained mostly unaffected by plasma treatment: the phagocytosis of bacteria, the oxidative burst, and the intracellular killing of microbes. Of note, plasma induced a strong induction of neutrophil extracellular traps (NETs). Decorated with antimicrobial proteins, NETs are web-like chromatin extrusions that entrap pathogens. These results have several implications for wound healing. Plasma-treated neutrophils were still capable of eradicating bacteria, which are frequently associated with non-healing wounds. In addition, plasma-induced NETs could aid in wound healing by providing an antibacterial scaffold to safeguard against further dissemination of microorganisms. Chronic wounds display a state of sustained inflammation and plasma induced apoptosis but not necrosis in lymphocytes. This was an important finding as necrosis, the involuntary cell death, is associated with the release of intracellular content, enhancing inflammation. By contrast, apoptosis dampens it as dead cells are cleared by macrophages inducing anti inflammatory responses. Further, the cytokine signature of plasma-treated leukocytes was largely non inflammatory, which could further decrease inflammation in wounds. Altogether, this work provided first insight with regard to effects and mechanisms of cold physical plasma treatment of wound-relevant leukocytes. Generally, these cells were affected by a plasma mediated modulation of their redox state. Future studies should include the possibility of redox modulation into their experimental approach to further elucidate the role of ROS/RNS in inflammation and possibly to improve existing wound healing therapies.
Multiple evidence in animal models and in humans suggest a beneficial role of cold physical
plasma in wound treatment. Yet, risk assessment studies are important to further foster therapeutic
advancement and acceptance of cold plasma in clinics. Accordingly, we investigated the long-term
side effects of repetitive plasma treatment over 14 consecutive days in a rodent full-thickness ear
wound model. Subsequently, animals were housed for 350 days and sacrificed thereafter. In blood,
systemic changes of the pro-inflammatory cytokines interleukin 1β and tumor necrosis factor α
were absent. Similarly, tumor marker levels of α-fetoprotein and calcitonin remained unchanged.
Using quantitative PCR, the expression levels of several cytokines and tumor markers in liver,
lung, and skin were found to be similar in the control and treatment group as well. Likewise,
histological and immunohistochemical analysis failed to detect abnormal morphological changes
and the presence of tumor markers such as carcinoembryonic antigen, α-fetoprotein, or the neighbor
of Punc 11. Absence of neoplastic lesions was confirmed by non-invasive imaging methods such as
anatomical magnetic resonance imaging and positron emission tomography-computed tomography.
Our results suggest that the beneficial effects of cold plasma in wound healing come without apparent
side effects including tumor formation or chronic inflammation.
: Human osteosarcoma (OS) is the most common primary malignant bone tumor occurring
most commonly in adolescents and young adults. Major improvements in disease-free survival have
been achieved by implementing a combination therapy consisting of radical surgical resection of the
tumor and systemic multi-agent chemotherapy. However, long-term survival remains poor, so novel
targeted therapies to improve outcomes for patients with osteosarcoma remains an area of active
research. This includes immunotherapy, photodynamic therapy, or treatment with nanoparticles.
Cold atmospheric plasma (CAP), a highly reactive (partially) ionized physical state, has been shown
to inherit a significant anticancer capacity, leading to a new field in medicine called “plasma oncology.”
The current article summarizes the potential of CAP in the treatment of human OS and reviews the
underlying molecular mode of action.
on-healing wounds continue to be a clinical challenge for patients and medical staff.
These wounds have a heterogeneous etiology, including diabetes and surgical trauma wounds. It is
therefore important to decipher molecular signatures that reflect the macroscopic process of wound
healing. To this end, we collected wound sponge dressings routinely used in vacuum assisted therapy
after surgical trauma to generate wound-derived protein profiles via global mass spectrometry.
We confidently identified 311 proteins in exudates. Among them were expected targets belonging to
the immunoglobulin superfamily, complement, and skin-derived proteins, such as keratins. Next to
several S100 proteins, chaperones, heat shock proteins, and immune modulators, the exudates
presented a number of redox proteins as well as a discrete neutrophil proteomic signature, including
for example cathepsin G, elastase, myeloperoxidase, CD66c, and lipocalin 2. We mapped over 200
post-translational modifications (PTMs; cysteine/methionine oxidation, tyrosine nitration, cysteine
trioxidation) to the proteomic profile, for example, in peroxiredoxin 1. Investigating manually
collected exudates, we confirmed presence of neutrophils and their products, such as microparticles
and fragments containing myeloperoxidase and DNA. These data confirmed known and identified
less known wound proteins and their PTMs, which may serve as resource for future studies on
human wound healing
Summary
The susceptibility of Candida albicans biofilms to a non‐thermal plasma treatment has been investigated in terms of growth, survival and cell viability by a series of in vitro experiments. For different time periods, the C. albicans strain SC5314 was treated with a microwave‐induced plasma torch (MiniMIP). The MiniMIP treatment had a strong effect (reduction factor (RF) = 2.97 after 50 s treatment) at a distance of 3 cm between the nozzle and the superior regions of the biofilms. In addition, a viability reduction of 77% after a 20 s plasma treatment and a metabolism reduction of 90% after a 40 s plasma treatment time were observed for C. albicans. After such a treatment, the biofilms revealed an altered morphology of their cells by atomic force microscopy (AFM). Additionally, fluorescence microscopy and confocal laser scanning microscopy (CLSM) analyses of plasma‐treated biofilms showed that an inactivation of cells mainly appeared on the bottom side of the biofilms. Thus, the plasma inactivation of the overgrown surface reveals a new possibility to combat biofilms.
Background: Cold atmospheric plasma (CAP) is increasingly used in the field of oncology.
Many of the mechanisms of action of CAP, such as inhibiting proliferation, DNA breakage, or the
destruction of cell membrane integrity, have been investigated in many different types of tumors.
In this regard, data are available from both in vivo and in vitro studies. Not only the direct treatment
of a tumor but also the influence on its blood supply play a decisive role in the success of the therapy
and the patient’s further prognosis. Whether the CAP influences this process is unknown, and the
first indications in this regard are addressed in this study. Methods: Two different devices, kINPen
and MiniJet, were used as CAP sources. Human endothelial cell line HDMEC were treated directly
and indirectly with CAP, and growth kinetics were performed. To indicate apoptotic processes,
caspase-3/7 assay and TUNEL assay were used. The influence of CAP on cellular metabolism
was examined using the MTT and glucose assay. After CAP exposure, tube formation assay was
performed to examine the capillary tube formation abilities of HDMEC and their migration was
messured in separate assays. To investigate in a possible mutagenic effect of CAP treatment,
a hypoxanthine-guanine-phosphoribosyl-transferase assay with non malignant cell (CCL-93) line was
performed. Results: The direct CAP treatment of the HDMEC showed a robust growth-inhibiting
effect, but the indirect one did not. The MMT assay showed an apparent reduction in cell metabolism
in the first 24 h after CAP treatment, which appeared to normalize 48 h and 72 h after CAP application.
These results were also confirmed by the glucose assay. The caspase 3/7 assay and TUNEL assay
showed a significant increase in apoptotic processes in the HDMEC after CAP treatment. These results
were independent of the CAP device. Both the migration and tube formation of HDMEC were
significant inhibited after CAP-treatment. No malignant effects could be demonstrated by the CAP
treatment on a non-malignant cell line.
Chondrosarcoma is the second most common malign bone tumor in adults. Surgical
resection of the tumor is recommended because of its resistance to clinical treatment such as
chemotherapy and radiation therapy. Thus, the prognosis for patients mainly depends on sufficient
surgical resection. Due to this, research on alternative therapies is needed. Cold atmospheric plasma
(CAP) is an ionized gas that contains various reactive species. Previous studies have shown an
anti-oncogenic potential of CAP on different cancer cell types. The current study examined the effects
of treatment with CAP on two chondrosarcoma cell lines (CAL-78, SW1353). Through proliferation
assay, the cell growth after CAP-treatment was determined. A strong antiproliferative effect for
both cell lines was detected. By fluorescein diacetate (FDA) assay and ATP release assay, alterations
in the cell membrane and associated translocation of low molecular weight particles through the
cytoplasmic membrane were observed. In supernatant, the non-membrane-permeable FDA and
endogenously synthesized ATP detected suggest an increased membrane permeability after CAP
treatment. Similar results were shown by the dextran-uptake assay. Furthermore, fluorescence
microscopic G-/F-actin assay was performed. G- and F-actin were selectively dyed, and the ratio
was measured. The presented results indicate CAP-induced changes in cell membrane function and
possible alterations in actin-cytoskeleton, which may contribute to the antiproliferative effects of CAP.
Molecular Mechanisms of the Efficacy of Cold Atmospheric Pressure Plasma (CAP) in Cancer Treatment
(2020)
Despite continuous advances in therapy, malignant melanoma is still among the deadliest
types of cancer. At the same time, owing to its high plasticity and immunogenicity, melanoma is
regarded as a model tumor entity when testing new treatment approaches. Cold physical plasma is a
novel anticancer tool that utilizes a plethora of reactive oxygen species (ROS) being deposited on the
target cells and tissues. To test whether plasma treatment would enhance the toxicity of an established
antitumor therapy, ionizing radiation, we combined both physical treatment modalities targeting
B16F10 murine melanoma cell in vitro. Repeated rather than single radiotherapy, in combination
with gas plasma-introduced ROS, induced apoptosis and cell cycle arrest in an additive fashion. In
tendency, gas plasma treatment sensitized the cells to subsequent radiotherapy rather than the other
way around. This was concomitant with increased levels of TNFα, IL6, and GM-CSF in supernatants.
Murine JAWS dendritic cells cultured in these supernatants showed an increased expression of cell
surface activation markers, such as MHCII and CD83. For PD-L1 and PD-L2, increased expression
was observed. Our results are the first to suggest an additive therapeutic effect of gas plasma and
radiotherapy, and translational tumor models are needed to develop this concept further.