Impact of Non-Invasive Physical Plasma on Heat Shock Protein Functionality in Eukaryotic Cells

Recently, biomedical research has increasingly investigated physical plasma as an innovative therapeutic approach with a number of therapeutic biomedical effects. It is known from radiation and chemotherapy that these applications can lead to the induction and activation of primarily cytoprotective heat shock proteins (HSP). HSP protect cells and tissues from physical, (bio)chemical, and physiological stress and, ultimately, along with other mechanisms, govern resistance and treatment failure. These mechanisms are well known and comparatively well studied in drug therapy. For therapies in the field of physical plasma medicine, however, extremely little data are available to date. In this review article, we provide an overview of the current studies on the interaction of physical plasma with the cellular HSP system.

Concise review of non-invasive physical plasma as a promising treatment option for radiation injuries of the skin

Radiation injury has a complex pathophysiology and can result in long-term impediment of the dermal barrier function. Historically, its treatment has been no different to that of thermal burns and it is not always possible to prevent an unpredictable and uncontrolled extension of the radiation-induced reactions. Non-invasive physical plasma (NIPP), a highly energised gas encompassing a combination of various reactive species, positively affects the key players involved in wound healing and proves to be a promising treatment option for chronic wounds and inflammatory skin disorders. Recent clinical evidence also suggests preliminary efficacy in radiation injury following therapeutic irradiation as a part of cancer therapy. Further research is warranted to also investigate the clinical value of NIPP in the context of unplanned or accidental radiation exposure, either as a topical treatment or possibly as an intraoperative procedure, to potentially improve the dermatological outcome and reduce symptoms in radiation victims.

Devitalization of Glioblastoma Cancer Cells by Non-invasive Physical Plasma: Modulation of Proliferative Signalling Cascades

BACKGROUND/AIM

Glioblastoma (GBM) is the most common and most lethal type of cancer of the central nervous system in adults. Despite aggressive treatment, which is based on surgical resection, if possible, followed by radiation and chemotherapy, a high recurrence rate and therapy resistance is observed. Thus, additional innovative therapies are urgently needed to improve the poor median survival of only 15 months. Treatment of solid tumours with non-invasive physical plasma (NIPP) represents such a novel and innovative anticancer procedure.

MATERIALS AND METHODS

In this study, we investigated the effect of NIPP, an ionized argon gas, on the in vitro growth of human GBM cell lines, LN-18 and U-87 MG. Proliferation was measured by live cell count. Subsequently, proliferative factors were analysed at the level of nucleic acids (polymerase chain reaction) and proteins (western blotting).

RESULTS

For both GBM lines, a treatment time-dependent decrease in growth was observed compared to controls. Additionally, NIPP treatment resulted in reduced rates of AKT serine/threonine kinase 1 (AKT1) and extracellular-regulated kinase 1/2 ERK1/2 expression, whereas expression of p21, proliferating cell nuclear antigen, and heat-shock proteins 90α and 90β was not affected. In both cell lines, a strong increase in expression of tumour-suppressive microRNA-1 (miR-1) was detected after exposure to NIPP.

CONCLUSION

Our results demonstrated that NIPP is able to efficiently attenuate growth of GBM cells and suggest AKT1, ERK1/2 and miR-1 to be pivotal factors of NIPP-modulated cellular signalling. Translated into the clinical setting, NIPP may represent a promising option for the treatment of GBM.

Impact of cold atmospheric pressure argon plasma on antibiotic sensitivity of methicillin-resistant Staphylococcus aureus strains in vitro

AIM

The antimicrobial activity of cold atmospheric pressure plasma (CAP), also called tissue tolerable plasma (TTP), could be a promising option to eradicate methicillin-sensitive as well as methicillin-resistant Staphylococcus aureus strains, which often colonize chronic wounds. Currently, the influence of CAP on the susceptibility of S. aureus to antibiotics is scarcely known, but could be important for treatment of wounds. Therefore, the aim of this study was to investigate whether CAP has an impact on the susceptibility of different S. aureus strains to different antibiotics.

METHOD

For assessment, the agar diffusion test with different antibiotic test disks (cefuroxime, gentamicin, oxacillin, vancomycin, ciprofloxacin, co-trimoxazole, clindamycin, erythromycin) was used. Test strains were spread on agar plates and CAP treated before the antibiotic disks were placed. After 24 hours cultivation, the inhibited growth zones were measured and differences statistically evaluated.

RESULTS

In most cases, CAP had a negligible influence on the susceptibility to antibiotics. For two strains, the susceptibility significantly decreased to β-lactam antibiotics.

CONCLUSION

Because CAP can influence the antibiotic susceptibility of S. aureus, before conducting combined treatment with local plasma application on wounds and systemic antibiotics, their interaction must be analysed in vitro to exclude unwanted combination effects.

Bactericidal efficacy of tissue tolerable plasma on microrough titanium dental implants: An in-vitro-study

Surface decontamination remains challenging in peri-implant infection therapy. To investigate the bactericidal efficacy of tissue tolerable plasma, S. mitis biofilms were created in vitro on 32 microrough titanium dental implants. Biofilm imaging was performed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The implants were either rinsed with 1% NaCl as negative control (C) or irradiated with a diode laser (DL) for 60 sec as positive control or plasma (TTP60, TTP120) for 60 or 120 sec. Subsequently, colony forming units (CFU) were counted. Post-treatment, implants were further examined using fluorescence microscopy (FM). Median CFU counts differed significantly between TTP60, TTP120 and C (2.19 and 2.2 vs. 3.29 log CFU/ml; p = 0.012 and 0.024). No significant difference was found between TTP60 and TTP120 (p = 0.958). Logarithmic reduction factors were (TTP60) 2.21, (TTP120) 1.93 and (DL) 0.59. Prior to treatment, CLSM and SEM detected adhering bacteria. Post-treatment FM recorded that the number of dead cells was higher using TTP compared to DL and C. In view of TTP's effectiveness, regardless of resistance patterns and absence of surface alteration, its use in peri-implant infection therapy is promising. The results encourage conducting clinical studies to investigate its impact on relevant parameters.

Cold atmospheric plasma for local infection control and subsequent pain reduction in a patient with chronic post-operative ear infection

Following surgery of cholesteatoma, a patient developed a chronic infection of the external auditory canal, including extended-spectrum β-lactamase producing Escherichia coli, which caused severe pain. The application of cold atmospheric plasma resulted in a significant reduction in pain and clearance of bacterial carriage, allowing antibiotics and analgesics to be ceased.