Electron spectroscopic analysis of the human lipid skin barrier: cold atmospheric plasma-induced changes in lipid composition

Non-invasive physical plasma for preventing radiation dermatitis in breast cancer: study protocol for a phase 3 randomised double-blind placebo-controlled trial (NIPP-RD III)

BACKGROUND

Radiation dermatitis (RD) is the most common side effect of breast irradiation, yet only few potent preventative and therapeutic options are available. Following encouraging results from a phase 1 and 2 trial on the topical use of non-invasive physical plasma (NIPP), a very well-tolerated physical treatment option to promote tissue regeneration generated from ambient air, we now present the study protocol for a planned phase 3 trial.

METHODS

In this randomised double-blind placebo-controlled trial, patients with breast cancer will be randomised (1:1) to receive either 120 s of NIPP or sham treatment with an identical device daily during hypofractionated breast irradiation following breast-conserving surgery. Standard skin care with urea lotion will be applied twice daily to the whole breast by all patients. Acute skin toxicity will be assessed weekly and includes clinician- (CTCAE v5.0) and patient-reported (modified RISRAS), and objective (spectrophotometry) assessments. The trial has started enrolment in the first quarter of 2024 and is projected to recruit 140 patients over 36 months.

DISCUSSION

This randomised controlled trial will recruit a homogeneous patient collective in terms of RD risk and aims to unequivocally establish the impact of NIPP on RD by employing a robust trial design, incorporating both the patient's perspective and validated objective outcome measures. If the addition of NIPP proves useful, it might reduce both physical and psychological distress caused by RD in numerous breast cancer patients and beyond.

TRIAL REGISTRATION

German Clinical Trial Registry DRKS00032560 (January 9th 2024).

Subcytotoxic transepidermal delivery using low intensity cold atmospheric plasma

Cold atmospheric plasma (CAP) has been utilized in various medical devices using its oxidative nature. Recent studies have provided evidence that CAP can facilitate the delivery of large, hydrophilic molecules through the epidermis to the dermis. On the other hand, a new approach called low-intensity CAP (LICAP) has been developed, allowing the plasma level to be controlled within a subtoxic range, thereby demonstrating various biological benefits without tissue damage. However, the ability of LICAP to enhance transepidermal delivery in sub-cytotoxic conditions has not been fully investigated. This study aims to determine the sub-cytotoxic range of exposure time for LICAP and, within the range, to investigate the effects of LICAP treatment on transepidermal drug delivery (TED) and mechanisms using human keratinocytes and a mouse model. For the in vitro studies, LICAP treatment was evaluated in human keratinocyte (HaCaT) cells by assessing reactive species production, DNA damage, and cytotoxicity profiles. Within the determined safety range, mechanistic analyses were conducted to examine LICAP-enhanced delivery pathways. mRNA expression and protein levels of tight and adherens junction genes were quantified, and changes in ultramicroscopic morphology of HaCaT monolayers were investigated. Intracellular delivery of fluorescein isothiocyanate (FITC)-dextran was also assessed. For the in vivo studies, E-cadherin expression and the transepidermal delivery (TED) of human epidermal growth factor (hEGF) were analyzed in LICAP-treated mouse dorsal skin. The upper safety range of LICAP exposure time, reducing cell viability by 70% (IC70 or LD30), was estimated at 34.3 s. Within the safety range, LICAP treatment downregulated multiple tight and adherens junction genes in HaCaT cells. Consistent with the in vitro results, the epidermal E-cadherin expression was reduced, and human epidermal growth factor (hEGF) was infiltrated in the dermis of the LICAP-treated mouse skin. Intercellular clefts were detected in the HaCaT cell monolayer immediately following LICAP treatment and intracellular delivery of FITC-dextran was confirmed after LICAP exposure. This study demonstrated that LICAP treatment enhances transepidermal permeation of hEGF, apparently via both paracellular and transcellular routes. Under our study conditions, LICAP treatment seems to be a novel approach to facilitate TED with low safety concerns in vitro. Further translational studies are needed for clinical evaluation.

Non-invasive physical plasma for preventing radiation dermatitis in breast cancer: Results from an intrapatient-randomised double-blind placebo-controlled trial

Background and Purpose

To investigate the effect of topical non-invasive physical plasma (NIPP), a volatile mix generated out of ambient air, on prevention of acute radiation dermatitis (RD) during and after whole-breast irradiation (WBI).

Materials and Methods

Lateral and medial breast halves were randomised within each patient to receive either 120 s of NIPP or sham treatment daily during WBI. Standard skin care with urea lotion was applied to the whole breast. Blinded acute skin toxicity was assessed weekly for each breast half separately and included clinician- (CTCAE) and patient-reported (modified RISRAS), and objective (spectrophotometry) assessments. As an additional external control, a comparable standard of care (SoC) patient collective from a previous prospective trial was used.

Results

Sixty-four patients were included. There were no significant differences between breast halves. Post-hoc comparison with a similar SoC control collective revealed OR = 0.28 (95% CI 0.11-0.76; p = 0.014) for grade ≥ 2 RD upon WBI completion, along with less hyperpigmentation (p < 0.001), oedema (p = 0.020), dry (p < 0.001) and moist desquamation (p = 0.017), pain, itching, and burning (p < 0.001 for each). Tolerability of NIPP was excellent and side effects were not observed.

Conclusion

Even though there were no differences between intrapatient-randomised breast halves, the overall incidence and severity of acute radiation-induced skin toxicity were considerably lower when compared to a prospectively collected SoC cohort. Our data suggest the potential benefit of NIPP in RD prevention. A randomised trial with a physical control group is warranted to confirm these promising results (DRKS00026225).

Enhanced Antimicrobial Activity through Synergistic Effects of Cold Atmospheric Plasma and Plant Secondary Metabolites: Opportunities and Challenges

The emergence of antibiotic resistant microorganisms possesses a great threat to human health and the environment. Considering the exponential increase in the spread of antibiotic resistant microorganisms, it would be prudent to consider the use of alternative antimicrobial agents or therapies. Only a sustainable, sustained, determined, and coordinated international effort will provide the solutions needed for the future. Plant secondary metabolites show bactericidal and bacteriostatic activity similar to that of conventional antibiotics. However, to effectively eliminate infection, secondary metabolites may need to be activated by heat treatment or combined with other therapies. Cold atmospheric plasma therapy is yet another novel approach that has proven antimicrobial effects. In this review, we explore the physiochemical mechanisms that may give rise to the improved antimicrobial activity of secondary metabolites when combined with cold atmospheric plasma therapy.

Applications and recent advances in transdermal drug delivery systems for the treatment of rheumatoid arthritis

Rheumatoid arthritis is a chronic, systemic autoimmune disease predominantly based on joint lesions with an extremely high disability and deformity rate. Several drugs have been used for the treatment of rheumatoid arthritis, but their use is limited by suboptimal bioavailability, serious adverse effects, and nonnegligible first-pass effects. In contrast, transdermal drug delivery systems (TDDSs) can avoid these drawbacks and improve patient compliance, making them a promising option for the treatment of rheumatoid arthritis (RA). Of course, TDDSs also face unique challenges, as the physiological barrier of the skin makes drug delivery somewhat limited. To overcome this barrier and maximize drug delivery efficiency, TDDSs have evolved in terms of the principle of transdermal facilitation and transdermal facilitation technology, and different generations of TDDSs have been derived, which have significantly improved transdermal efficiency and even achieved individualized controlled drug delivery. In this review, we summarize the different generations of transdermal drug delivery systems, the corresponding transdermal strategies, and their applications in the treatment of RA.

Cold Atmospheric Plasma: A Promising and Safe Therapeutic Strategy for Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Microbial infection, immune system dysfunction, and skin barrier defunctionalization have been regarded as the central events in AD pathogenesis. Cold atmospheric plasma (CAP) is an unbound system composed of many free electrons, ions, and neutral particles, with macroscopic time and spatial scales. Based on dielectric barrier discharge, glow discharge, corona discharge, or arch discharge, CAP is generated at normal atmospheric pressure. Its special physical properties maintain its temperature at 20°C-40°C, combining the advantages of high safety and strong ionic activity. CAP has been tentatively used in inflammatory or pruritic skin disorders such as psoriasis, pruritus, and ichthyosis. Increasing data suggest that CAP can attack the microbial structure due to its unique effects, such as heat, ultraviolet radiation, and free radicals, resulting in its inactivation. Meanwhile, CAP regulates reactive oxygen species and reactive nitrogen species in and out of the cells, thereby improving cell immunocompetence. In addition, CAP has a beneficial effect on the skin barrier function via changing the skin lipid contents and increasing the skin permeability to drugs. This review summarizes the potential effects of CAP on the major pathogenic causes of AD and discusses the safety of CAP application in dermatology in order to expand the clinical application value of CAP to AD.

Non-Invasive Physical Plasma for Preventing Radiation Dermatitis in Breast Cancer: A First-In-Human Feasibility Study

Radiation dermatitis (RD) is the most common acute side effect of breast irradiation. More than a century following the therapeutic utilisation of X-rays, potent preventative and therapeutic options are still lacking. Non-invasive physical plasma (NIPP) is an emerging approach towards treatment of various dermatological disorders. In this study, we sought to determine the safety and feasibility of a NIPP device on RD. Thirty patients undergoing hypofractionated whole-breast irradiation were included. Parallel to radiation treatment, the irradiated breast was treated with NIPP with different application regimens. RD was assessed during and after NIPP/radiation, using clinician- and patient-reported outcomes. Additionally, safety and feasibility features were recorded. None of the patients was prescribed topical corticosteroids and none considered the treatment to be unpleasant. RD was less frequent and milder in comparison with standard skin care. Neither NIPP-related adverse events nor side effects were reported. This proven safety and feasibility profile of a topical NIPP device in the prevention and treatment of RD will be used as the framework for a larger intrapatient-randomised double-blind placebo-controlled trial, using objective and patient-reported outcome measures as an endpoint.

Plasma Dermatology: Skin Therapy Using Cold Atmospheric Plasma

Cold atmospheric plasma-based plasma medicine has been expanding the diversity of its specialties. As an emerging branch, plasma dermatology takes advantage of the beneficial complexity of plasma constituents (e.g., reactive oxygen and nitrogen species, UV photons, and electromagnetic emission), technical versatility (e.g., direct irradiation and indirect aqueous treatment), and practical feasibility (e.g., hand-held compact device and clinician-friendly operation). The objective of this comprehensive review is to summarize recent advances in the CAP-dominated skin therapy by broadly covering three aspects. We start with plasma optimisation of intact skin, detailing the effect of CAP on skin lipids, cells, histology, and blood circulation. We then conduct a clinically oriented and thorough dissection of CAP treatment of various skin diseases, focusing on the wound healing, inflammatory disorders, infectious conditions, parasitic infestations, cutaneous malignancies, and alopecia. Finally, we conclude with a brief analysis on the safety aspect of CAP treatment and a proposal on how to mitigate the potential risks. This comprehensive review endeavors to serve as a mini textbook for clinical dermatologists and a practical manual for plasma biotechnologists. Our collective goal is to consolidate plasma dermatology’s lead in modern personalized medicine.

Atmospheric Pressure Plasma Irradiation Facilitates Transdermal Permeability of Aniline Blue on Porcine Skin and the Cellular Permeability of Keratinocytes with the Production of Nitric Oxide

The transdermal delivery system of nutrients, cosmetics, and drugs is particularly attractive for painless, noninvasive delivery and sustainable release. Recently, atmospheric pressure plasma techniques have been of great interest to improve the drug absorption rate in transdermal delivery. Currently, plasma-mediated changes in the lipid composition of the stratum corneum are considered a possible mechanism to increase transdermal permeability. Nevertheless, its molecular and cellular mechanisms in transdermal delivery have been largely confined and still veiled. Herein, we present the effects of cold plasma on transdermal transmission on porcine skin and the cellular permeability of keratinocytes and further demonstrate the production of nitric oxide from keratinocytes. Consequently, argon plasma irradiation for 60 s resulted in 2.5-fold higher transdermal absorption of aniline blue dye on porcine skin compared to the nontreated control. In addition, the plasma-treated keratinocytes showed an increased transmission of high-molecular-weight molecules (70 and 150 kDa) with the production of nitric oxide. Therefore, these findings suggest a promoting effect of low-temperature plasma on transdermal absorption, even for high-molecular-weight molecules. Moreover, plasma-induced nitric oxide from keratinocytes is likely to regulate transdermal permeability in the epidermal layer.

Analgesic effect of topical lidocaine is enhanced by cold atmospheric plasma pretreatment in facial CO2 laser treatments

BACKGROUND

Topical anesthesia is widely used in many dermatological and cosmetic procedures. Nevertheless, the stratum corneum serves as the skin barrier, impedes the transdermal drug delivery greatly, and results in insufficient analgesia. Cold atmospheric plasma (CAP) has been researched as a transdermal drug delivery promoter with ex vivo experiments for a few years, while clinical trials are scarce.

AIMS

To assess the efficacy and safety of CAP as a pretreatment to improve the transdermal absorption of topical anesthetic cream before the CO₂ laser treatment for postacne scars in the human body.

PATIENTS/METHODS

Twenty patients, seeking full facial laser treatment for atrophic acne scars, underwent a randomized split-face study. One side of the face was pretreated by CAP before topical anesthetic cream was applied, and the other side was applied with topical anesthetic cream only as control. After that, the subjects went through full-face fractional CO₂ laser treatment of postacne scars. They were asked to score the pain on a visual analogue scale (VAS) after the laser treatment to measure the anesthesia effects which indicates the transdermal absorption of the cream. Possible adverse effects of the plasma were recorded during the pretreatment including associated pain, heat, erythema, and edema.

RESULTS

The VAS score of the treated side was statistically lower (5.1 ± 2.1) compared with the nontreated side (6.3 ± 1.9), with a mean difference of 1.3 (95% confidence interval [CI], 0.6-1.9; P < .0001). No severe adverse event was reported, and all the disturbing sensations and symptoms (pain, heat, and edema) were evaluated as mild with no mean score surpassing 4.0.

CONCLUSION

Plasma pretreatment of 5 minutes before topical anesthetic cream application gives significant pain reduction during the laser procedures, showing the potential effects of CAP on promoting transdermal drug delivery, with no obvious adverse effects reported.

Transdermal delivery of topical lidocaine in a mouse model is enhanced by treatment with cold atmospheric plasma

BACKGROUND

Topical anesthetics are widely used in dermatology and cosmetology to alleviate the pain from nonsurgical cosmetic procedures, while the transdermal drug delivery is limited by the skin barrier. Cold atmospheric plasma (CAP) is a potential approach used for skin pretreatment to enhance transdermal delivery of topical medications.

AIMS

To assess the efficacy of CAP as a pretreatment to improve the transdermal delivery of topical anesthetic.

METHODS

First, we conducted ex vivo permeation studies on 30 mice with a Franz cell diffusion experiment. CAP irradiations of different intensity and duration were pretreated on the epidermal layer of mice before topical lidocaine applied, with the control group received no pretreatment. The amount of drug penetrated through the skin and drug flux were determined by high-performance liquid chromatography. Then, we treated 3 living mice with CAP followed by application of methylene blue cream (MB) and used skin biopsies to measure penetration depth by microscope. Last, we measured the transepidermal water loss (TEWL) of mouse skin in vivo before and after CAP treatment to observe its effect on the skin barrier function.

RESULTS

In the permeation study, the transdermal flux of lidocaine was enhanced to 1.97 times of the control samples by CAP pretreatment. We also observed that the accumulative amount of lidocaine varied with the duration of the CAP treatment in a biphasic manner. In the MB penetration study, significant amount of MB deposition was observed under the epidermis and deeper parts of the skin after CAP pretreatment compared with the control sample. A sharp increase in TEWL value was observed directly after the CAP treatment, but 30 minutes later, it began to decrease and recovered to baseline in the next 3 hours, indicating that the skin barrier property had been changed reversibly.

CONCLUSIONS

Our studies suggested that the transdermal absorption of topical lidocaine can be efficiently and safely enhanced by pretreatment of the skin with CAP. We believe that CAP could be used as an assistance to improve analgesia in dermatology.

An Innovative Therapeutic Option for the Treatment of Skeletal Sarcomas: Elimination of Osteo- and Ewing's Sarcoma Cells Using Physical Gas Plasma

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.

Applications of cold atmospheric plasma for transdermal drug delivery: a review

Although transdermal drug delivery would be very useful for the treatment of many diseases, in practice it is difficult to accomplish for the obstruction of the stratum corneum. The application of cold atmospheric plasma (CAP) as a pretreatment to the skin surface helps to enhance the delivery of topically applied drugs into the skin and the systemic circulation. CAP can change the skin properties to improve drug penetration by various different effects based on its multiple components. This review first introduces the skin barrier properties and some traditional transdermal drug delivery strategies. Next what is known about the application of CAP in transdermal drug delivery has been summarized, including the mechanisms and possible side effects. We believe that CAP could be developed as a non-invasive and efficient pretreatment to improve the transdermal permeation of drugs in clinical practice, although more research needs to be done to overcome the challenges. Graphical Abstract.

ROS from Physical Plasmas: Redox Chemistry for Biomedical Therapy

Physical plasmas generate unique mixes of reactive oxygen and nitrogen species (RONS or ROS). Only a bit more than a decade ago, these plasmas, operating at body temperature, started to be considered for medical therapy with considerably little mechanistic redox chemistry or biomedical research existing on that topic at that time. Today, a vast body of evidence is available on physical plasma-derived ROS, from their spatiotemporal resolution in the plasma gas phase to sophisticated chemical and biochemical analysis of these species once dissolved in liquids. Data from in silico analysis dissected potential reaction pathways of plasma-derived reactive species with biological membranes, and in vitro and in vivo experiments in cell and animal disease models identified molecular mechanisms and potential therapeutic benefits of physical plasmas. In 2013, the first medical plasma systems entered the European market as class IIa devices and have proven to be a valuable resource in dermatology, especially for supporting the healing of chronic wounds. The first results in cancer patients treated with plasma are promising, too. Due to the many potentials of this blooming new field ahead, there is a need to highlight the main concepts distilled from plasma research in chemistry and biology that serve as a mechanistic link between plasma physics (how and which plasma-derived ROS are produced) and therapy (what is the medical benefit). This inevitably puts cellular membranes in focus, as these are the natural interphase between ROS produced by plasmas and translation of their chemical reactivity into distinct biological responses.

Chemistry and biochemistry of cold physical plasma derived reactive species in liquids

Reactive oxygen and nitrogen species deposited by cold physical plasma are proposed as predominant effectors in the interaction between discharge and biomedical application. Most reactive species found in plasma sources are known in biology for inter- and intracellular communication (redox signaling) and mammalian cells are equipped to interpret the plasma derived redox signal. As such, considerable effort has been put into the investigation of potential clinical applications and the underlying mechanism, with a special emphasis on conditions orchestrated significantly via redox signaling. Among these, immune system control in wound healing and cancer control stands out with promising in vitro and in vivo effects. From the fundamental point of view, further insight in the interaction of the plasma-derived species with biological systems is desired to (a) optimize treatment conditions, (b) identify new fields of application, (c) to improve plasma source design, and (d) to identify the trajectories of reactive species. Knowledge on the biochemical reactivity of non-thermal plasmas is compiled and discussed. While there is considerable knowledge on proteins, lipids and carbohydrates have not received the attention deserved. Nucleic acids have been profoundly investigated yet focusing on molecule functionality rather than chemistry. The data collected underline the efforts taken to understand the fundamentals of plasma medicine but also indicate 'no man's lands' waiting to be discovered.

[Plasma medicine in dermatology: Mechanisms of action and clinical applications]

Plasma medicine has developed into an innovative field of research showing high potential. Since the establishment of cold atmospheric plasma, new, multifaceted medical treatment opportunities have become available. Within a short time a multidisciplinary special interest group of medical scientists, physicists, and biologists was created, aiming to understand plasma medicine and answer clinical as well as scientific questions. In dermatology, new horizons are being opened for wound healing, tissue regeneration, treatment of skin infections, and tumor therapy. A major task will be the introduction of plasma into clinical medicine and, simultaneously, the further investigation of the mechanisms of action of plasma at the cellular level. Only then can the safety of plasma treatment in patients be assured.

Molecular interactions of plant oil components with stratum corneum lipids correlate with clinical measures of skin barrier function

Plant-derived oils consisting of triglycerides and small amounts of free fatty acids (FFAs) are commonly used in skincare regimens. FFAs are known to disrupt skin barrier function. The objective of this study was to mechanistically study the effects of FFAs, triglycerides and their mixtures on skin barrier function. The effects of oleic acid (OA), glyceryl trioleate (GT) and OA/GT mixtures on skin barrier were assessed in vivo through measurement of transepidermal water loss (TEWL) and fluorescein dye penetration before and after a single application. OA's effects on stratum corneum (SC) lipid order in vivo were measured with infrared spectroscopy through application of perdeuterated OA (OA-d34 ). Studies of the interaction of OA and GT with skin lipids included imaging the distribution of OA-d34 and GT ex vivo with IR microspectroscopy and thermodynamic analysis of mixtures in aqueous monolayers. The oil mixtures increased both TEWL and fluorescein penetration 24 h after a single application in an OA dose-dependent manner, with the highest increase from treatment with pure OA. OA-d34 penetrated into skin and disordered SC lipids. Furthermore, the ex vivo IR imaging studies showed that OA-d34 permeated to the dermal/epidermal junction while GT remained in the SC. The monolayer experiments showed preferential interspecies interactions between OA and SC lipids, while the mixing between GT and SC lipids was not thermodynamically preferred. The FFA component of plant oils may disrupt skin barrier function. The affinity between plant oil components and SC lipids likely determines the extent of their penetration and clinically measurable effects on skin barrier functions.

Inactivation of microbes and macromolecules by atmospheric-pressure plasma jets

Plasma is ionized gas, which is found in various forms in nature and can also be generated artificially. A variety of cold atmospheric-pressure plasmas are currently being investigated for their clinical utility, and first studies reporting on the treatment of patients showed that plasma treatment may support the wound healing process. One of the benefits of plasma treatment is the effective inactivation of bacteria including tenacious pathogens such as Pseudomonas aeruginosa or multiresistant Staphylococcus aureus (MRSA). Neither the molecular mechanisms promoting wound healing nor those underlying bacterial inactivation are fully understood yet. The review has a focus on plasma jets, a particular type of cold atmospheric-pressure plasma sources featuring an indirect treatment whereby the treated substrates do not come into contact with the plasma directly but are exposed to the plasma-emitted reactive species and photons. Such plasma jets are being employed as tools in basic research regarding the effects of plasmas on biological samples. This review provides a brief overview on the recent clinical investigations into the benefits of cold atmospheric-pressure plasmas. It then describes our current understanding of the mechanisms leading to bacterial inactivation and inactivation of biomacromolecules gained by employing plasma jets.

Alleviation of chronic venous leg ulcers with a hand-held dielectric barrier discharge plasma generator (PlasmaDerm(®) VU-2010): results of a monocentric, two-armed, open, prospective, randomized and controlled trial (NCT01415622)

BACKGROUND

Cold atmospheric plasma (CAP, i.e. ionized air) is an innovating promising tool in reducing bacteria.

OBJECTIVE

We conducted the first clinical trial with the novel PlasmaDerm® VU-2010 device to assess safety and, as secondary endpoints, efficacy and applicability of 45 s/cm(2) cold atmospheric plasma as add-on therapy against chronic venous leg ulcers.

METHODS

From April 2011 to April 2012, 14 patients were randomized to receive standardized modern wound care (n = 7) or plasma in addition to standard care (n = 7) 3× per week for 8 weeks. The ulcer size was determined weekly (Visitrak® , photodocumentation). Bacterial load (bacterial swabs, contact agar plates) and pain during and between treatments (visual analogue scales) were assessed. Patients and doctors rated the applicability of plasma (questionnaires).

RESULTS

The plasma treatment was safe with 2 SAEs and 77 AEs approximately equally distributed among both groups (P = 0.77 and P = 1.0, Fisher's exact test). Two AEs probably related to plasma. Plasma treatment resulted in a significant reduction in lesional bacterial load (P = 0.04, Wilcoxon signed-rank test). A more than 50% ulcer size reduction was noted in 5/7 and 4/7 patients in the standard and plasma groups, respectively, and a greater size reduction occurred in the plasma group (plasma -5.3 cm(2) , standard: -3.4 cm(2) ) (non-significant, P = 0.42, log-rank test). The only ulcer that closed after 7 weeks received plasma. Patients in the plasma group quoted less pain compared to the control group. The plasma applicability was not rated inferior to standard wound care (P = 0.94, Wilcoxon-Mann-Whitney test). Physicians would recommend (P = 0.06, Wilcoxon-Mann-Whitney test) or repeat (P = 0.08, Wilcoxon-Mann-Whitney test) plasma treatment by trend.

CONCLUSION

Cold atmospheric plasma displays favourable antibacterial effects. We demonstrated that plasma treatment with the PlasmaDerm® VU-2010 device is safe and effective in patients with chronic venous leg ulcers. Thus, larger controlled trials and the development of devices with larger application surfaces are warranted.