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Improvement of cutaneous microcirculation by cold atmospheric plasma(CAP): Results of a controlled, prospective cohort study
Tobias Kisch a,⁎, Andreas Helmke b, Sophie Schleusser a, Jungin Song a, Eirini Liodaki a, Felix Hagen Stang a,Peter Mailaender a, Robert Kraemer a
a Department of Plastic Surgery, Hand Surgery, Burn Unit, University Hospital of Schleswig-Holstein, Campus Lübeck, University of Lübeck, Lübeck, Germanyb Application Center for Plasma and Photonic APP, Fraunhofer Institute for Surface Engineering and Thin Films IST, Göttingen, Germany
Abbreviations: O3, ozone; OH, hydroxyl; H2O2, hydronitrogen oxides of different oxidation states; CAP, coatmospheric cold plasma; APP, cold atmospheric pressurplasma; DBD, dielectric barrier discharge; IL, interleukin;Mtein; TGF, transforming growth factor; SMA, smoothmuscest; O2C, oxygen-to-see; BMI, body mass index; AU, arbsynthase; HaCaT, human adult low calciumhigh temperatutor receptor; FGF, fibroblast growth factor.⁎ Corresponding author at: Department of Plastic Surge
of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, GermanyE-mail address: [email protected] (T. Kisch).
Article history:Received 14 August 2015Revised 2 December 2015Accepted 3 December 2015Available online 3 December 2015
Background: Cold atmospheric plasma (CAP) has proven its benefits in the reduction of various bacteria and fungiin both in vitro and in vivo studies. Moreover, CAP generated by dielectric barrier discharge (DBD) promotedwound healing in vivo. Charged particles, chemically reactive species (such as O3, OH, H2O2, O, NxOy), ultravioletradiation (UV-A andUV-B), strong oscillating electricfields aswell asweak electric currents are produced byDBDoperated in air. However, wound healing is a complex process, depending on nutrient and oxygen supply viacutaneous blood circulation. Therefore, this study examined the effects of CAP on cutaneous microcirculationin a prospective cohort setting.Hypothesis: Cold atmospheric plasma application enhances cutaneous microcirculation.Methods:Microcirculatory data of 20 healthy subjects (11males, 9 females; mean age 35.2± 13.8 years; BMI24.3 ± 3.1 kg/m2) were recorded continuously at a defined skin area at the radial forearm. Under standard-ized conditions, microcirculatory measurements were performed using a combined laser Doppler andphotospectrometry system. After baseline measurement, CAP was applied by a DBD plasma device for90 s to the same defined skin area of 22.5 cm2. Immediately after the application cutaneousmicrocirculationwas assessed for 30 min at the same site.Results: After CAP application, tissue oxygen saturation immediately increased by 24% (63.8 ± 13.8% from51.4 ± 13.2% at baseline, p b 0.001) and stayed significantly elevated for 8 min. Cutaneous blood flow in-creased by 73% (41.0 ± 31.2 AU from 23.7 ± 20.8 AU at baseline, p b 0.001) and remained upregulatedfor 11 min. Furthermore, cutaneous blood flow showed two peaks at 14 (29.8 ± 25.0 AU, p = 0.049) and19 min (29.8 ± 22.6 AU, p = 0.048) after treatment. Postcapillary venous filling pressure continuouslyincreased, but showed no significant change vs. baseline in the non-specific BMI group. Subgroup analysisrevealed that tissue oxygen saturation, postcapillary venous filling pressure and blood flow increasedmore in case of a lower BMI.Conclusion: CAP increases cutaneous tissue oxygen saturation and capillary blood flow at the radial forearmof healthy volunteers. These results support recently published data on wound healing after CAP treatment.However, further studies are needed to determine if this treatment can improve the reduced microcircula-tion in diabetic foot ulcers. Moreover, repetitive application protocols have to be compared with a singlesession treatment approach.
gen peroxide; O, oxygen; NxOy,ld atmospheric plasma; ACP,e plasma; TTP, tissue-tolerableCP,monocyte chemotactic pro-le antibody; ROI, region of inter-itrary units; NOS, nitric oxidere; EGFR, epithelial growth fac-
ry and Hand Surgery, University.
Introduction
Plasma is a state of matter other than solids, liquids or gases; there-fore, it is referred to as the fourth state of matter. It can be technicallygenerated by applying high voltages to narrow gas-filled gaps which re-sults in strong electric fields. A prominent concept to produce plasmasat atmospheric pressure is the dielectric barrier discharge (DBD),where at least one of the electrodes is covered by an insulatingmaterialwhich significantly limits current flow and gas heating (Kogelschatz,2003). Within the electric fields, primarily electrons gain energywhich is then distributed by collisions with gas particles. This leads to
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excitation, dissociation and ionization of formerly neutral and inertgases like air, argon or helium. As a consequence, charged particles,chemically reactive species (O3, OH, H2O2, O, NxOy, etc.), ultraviolet radi-ation (UV-A and UV-B), strong oscillating electric fields as well as weakelectric currents are produced byDBD operated in air. Common plasmasused to sterilize medical devices or for tissue cauterization are eitherthermal plasmas (interaction dominated by heat transfer) or operateat reduced pressure in evacuated vessels. As a relatively new option,cold atmospheric plasma (CAP), also known as atmospheric cold plasma(ACP), cold atmospheric pressure plasma (APP) or tissue-tolerable plas-ma (TTP) is available. These plasmas are characterized by the negligibil-ity of heat induced effects on cells and tissue, thus facilitating moregentle and complex interactions induced by chemical species, radiationas well as electric fields and currents simultaneously. Two device con-cepts can be distinguished: i) indirect sources, where the plasma is gen-erated in a cavity between two electrodes and is blown out via a gasstream (jet) onto a surface; and ii) direct sources without a gas stream,where the plasma is generated directly on the surface of the treatedobject (Tiede et al., 2014).
CAP has shown its benefits in the reduction of various fungi andbacteria (Maisch et al., 2012; Shimizu et al., 2011; Isbary et al., 2012), in-cluding antibiotic-resistant biofilm-forming strains (Mai-Prochnowet al., 2014) in both in vitro and in vivo studies. Since multiple modesof action are involved in the treatment of surfaces using CAP, inductionof resistance in bacteria is very unlikely. Furthermore, other effects ofCAP have been described, such as a selective destruction of cancercells in vitro by modifying the molecular structure of proteins (Zhanget al., 2015). Moreover, wound healing was accelerated in an in vivomodel by an increase of IL-6, IL-8, MCP-1, TGF-b1/2, collagen type I,and alpha-SMA observed after a 2-min treatment (Arndt et al., 2013).Other animalmodels showed that CAP promotedwound healing in a re-petitive application setting (Nasruddin et al., 2014; Ermolaeva et al.,2011). In studies evaluating CAP in humans, accelerated wound healingwas observed with chronic wounds (Isbary et al., 2013; Brehmer et al.,2015) and at skin graft donor sites (Heinlin et al., 2013).
However, the effects of CAP on wound healing still remain unclear.Epithelialization depends on various factors. One of the most criticalfactors is vascularization which is vital for the supply of the cells withoxygen and nutrients. Furthermore, enhanced microcirculation can im-prove vascularization through shear stress. Therefore, the aim of thisstudy was to examine the effects of CAP on cutaneous microcirculationin a prospective cohort setting.
Methods
Ethical approval
This study was performed in accordance with the standards set bythe Declaration of Helsinki. It complies with the reporting standardsestablished by the Strengthening the Reporting of Observational Studiesin Epidemiology (STROBE) guidelines. The protocol was approvedby the Institutional Ethics Committee under authorization number14-266 and is registered at ClinicalTrials.gov (NCT02417818).
Study design and setting
The study was designed as a prospective, controlled cohort trial andperformed from March to July 2015 in a German University Hospital.Informed consent was obtained and inclusion criteria were checked
Fig. 1. a. Microcirculatory effects of cold atmospheric plasma (CAP) on cutaneous tissue oxygenoxygen saturation significantly increased vs. baseline by 24% and remained elevated for 8 min.terwards, it showed no significant differences vs. baseline. Data is given asmean± SEM. #=p b
participants with a BMI b 25 (n= 13) cutaneous tissue oxygen saturation effects after cold atmnon-specific BMI group. Here, one minute after the application of CAP tissue oxygen saturatioparticipants with a BMI≥ 25 (n= 7) cutaneous tissue oxygen saturation was significantly incrupregulation until 7 min.
before study subjects were included in the study. Participants had arefrain from taking caffeine-containing drinks and food for at leasttwo hours and strenuous exercise for 24 h before testing. The room inwhich tests were performed was temperature-controlled at about22 °C and 50% humidity.
Participants
Eligibility criteria were healthy male and female subjects aged≥18 years who were able to give their informed consent. Exclusioncriteria were soft tissue injuries or skin inflammation at the forearm,systemic skin diseases, peripheral arterial occlusive disease, vasculitis,diabetes mellitus, chronic kidney or liver disease, cardiac dysfunction,arterial hypo- or hypertension. Moreover, subjects taking vasoactivemedications or with a history of drug abuse were excluded. Subgroupanalysis was performed for a BMI b 25 and a BMI ≥ 25.
Treatment protocol
Participants had to rest for 15 min prior to testing on a long up-holstered seat. Baseline measurements were then carried out at theregion of interest (ROI) on the mid of the palmar forearm for 1 min.Subsequently, PlasmaDerm®FLEX9060 (CINOGY GmbH, Duderstadt,Germany) was used 90 s for the application of cold atmospheric plas-ma (CAP) to a defined skin area of 22.5 cm2 in size, centered at theROI. This direct plasma source is based on the concept of single-electrode dielectric barrier discharge (SE-DBD). It has a single high-voltage electrode and the tissue itself acts as the second electrode(counter electrode). The electrode was pressed gently onto thearea, whereby the skin surface structure ensures a constant gap filledwith ambient air of 2.00 mm. The electrode is operated at high-voltage pulses with some 10 μs duration at amplitudes of up to10 kV and a constant repetition rate of 300 Hz. Mean input powerduring the application amounts to 450 mW. Immediately after theapplication, cutaneous microcirculation was assessed at the samearea as the baseline measurement over a period of 30 min. Duringthe whole procedure, participants stayed isolated from sensory im-pressions positioned horizontally on the long upholstered seat.
Data assessment
To evaluate the cutaneous microcirculation, a non-invasive com-bined laser Doppler and photospectrometry system (Oxygen-to-see,Lea Medizintechnik, Giessen, Germany) was used. The Oxygen-to-seesystem assesses the microcirculation in a quantitative way based onthe transmission of continuous-wave laser light and white light. As de-scribed earlier (Kisch et al., 2015a, 2015b), it combines hemoglobinmeasurement and the principle of blood flowmeasurement by a singleoptical fiber probe to assess capillary blood flow, tissue oxygen satura-tion and postcapillary venous filling pressure at a depth of 1–2 mm.
Bias
To avoid structuralmeasurement bias, environmental factors duringcold atmospheric plasma (CAP) application andmicrocirculation assess-mentwere standardized. Moreover, artifacts resulting fromprobe dislo-cation were prevented by fixing the fiber probe at the same distinctlocation in each subject. The outcome variable selection bias was
saturation in the non-specific BMI group (n= 20). Oneminute after the application tissueThe initial CAP application boosted cutaneous tissue oxygenation to its highest extend. Af-0.001, §=p b 0.01 and *=p b 0.05 comparedwith baseline. b. In the subgroup includingospheric plasma (CAP) application were nearly similar to the effects shown in the wholen significantly increased and remained elevated until 10 min. c. The subgroup includingeased 1 min after cold atmospheric plasma (CAP) application and showed an insignificant
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avoided by presenting all assessed cutaneousmicrocirculatory variablesmeasured by the Oxygen-to-see system.
Statistical analysis
SigmaPlot™ for Windows Version 12.3 (Systat Software Inc., SanJosé, USA) was used for statistical analysis. Repeated measures ANOVAand a posthoc Holm–Sidak procedure were used due to its power. Ap-value of less than 0.05 was considered statistical significant. Datawas provided as mean ± SD.
Results
Participants' descriptive data
20 healthy subjects (11 males, 9 females) were enrolled in the eval-uation of cutaneousmicrocirculatory effects of cold atmospheric plasma(CAP). Mean age was 35.2 ± 13.8 years and mean BMI was 24.3 ±3.1 kg/m2 (n= 13 with a BMI b 25, n = 7 with a BMI ≥ 25). All partic-ipants were nonsmokers.
Adverse effects
The participants tolerated the treatment very well and did not showany pain during or after the application.While treatmentwas performed,a sizzle sound (300 Hz) indicated that the CAP was actually created.
creased the cutaneous tissue oxygen saturation by 24% (percentagechange) after one minute, 22% after two minutes and 15% after five mi-nutes (p b 0.001 vs. baseline). Tissue oxygen saturation was 51.4 ±13.2% at baseline, 63.8 ± 13.8% at one minute, 62.5 ± 14% at twominutes and 59 ± 13.1% at five minutes after treatment. Until eightminutes after treatment a significant increase was observed (56.0 ±14.1%, p = 0.043). After that no further statistically significant changesfrom baseline were detected. In the subgroup including participantswith a BMI b 25 tissue oxygen saturation effects were comparable tothe results in the non-specific BMI group. Here, baseline was 53.0 ±12.6% and an elevation one minute after CAP showed an increase to65.6 ± 14.1%. Significant increase was displayed for ten minutes. Thesubgroup including participants with a BMI ≥ 25 showed an increaseto 60.3 ± 13.6% from the baseline (48.5 ± 14.8%) one minute afterCAP application. Afterwards, no significant differences to baselinewere seen.
Cutaneous postcapillary venous filling pressure (Fig. 2a–c)Postcapillary venous filling pressure was 55.3 ± 9.6 arbitrary units
[AU] at baseline and showed a constant but non-significant increaseover the measuring period (p N 0.05) in the non-specific BMI group.One minute after treatment, postcapillary venous filling pressure was56.5 ± 12.1 AU. Then, it showed an upward trend with 58.2 ±10.1 AU at twenty minutes and 58.7 ± 11.2 AU at thirty minutes afterthe intervention. In the subgroup including participants with aBMI b 25 baseline was 54.2 ± 10.0 AU. A significant increase wasshown in this subgroup from one minute after application of CAP(57.4 ± 14.1 AU) until the end of the measuring period (59.2 ±
Fig. 2. a. Microcirculatory effects of cold atmospheric plasma (CAP) on cutaneous postcapillary vpostcapillary venous filling pressure showed a non-significant increase, tending back to baselinward trend. However, no significant changes vs. baseline were shown. b. The subgroup inclupostcapillary venousfilling pressure in comparison to the baseline. Itwas elevated 1min after CAincluding participantswith a BMI≥ 25 (n=7) showed an irregular postcapillary venous fillingwas not obvious.
12.4 AU) 30 min after the application. In the subgroup including partic-ipants with a BMI≥ 25 no significant changes from baseline were seen.
change) at one minute, 58% at two minutes and 42% at five minutesafter the application of cold atmospheric plasma (p b 0.001) in thenon-specific BMI group. Capillary blood flow was 23.7 ± 20.8 AU atbaseline, 41.0 ± 31.2 AU at one minute, 37.5 ± 28.9 AU at two minutesand 33.6 ± 25.5 AU at five minutes after treatment. It remained signif-icantly elevated until 11 min after treatment with 30.5 ± 26.2 AU(p = 0.018 vs. baseline). Moreover, a significant upregulation was ob-served at 14 min after treatment with 29.8 ± 25.0 AU (p = 0.049)and at 19 min with 29.8 ± 22.6 AU (p = 0.048). Afterwards, therewere no more significant changes compared with baseline. The sub-group including participants with a BMI b 25 showed very similar re-sults. Here, cutaneous blood flow was boosted to 37.8 ± 21.4 AU from19.7 ± 10.5 AU (baseline) one minute after the application of CAP. Itremained significantly elevated until minute ten (25.9 ± 13.6 AU, p =0.040) and stayed insignificantly increased. Atminute 28 another signif-icant increasewas seen (27.1±19.0 AU, p=0.043). On the other hand,the subgroup including participants with a BMI ≥ 25 revealed a signifi-cant increase one minute after CAP application from 31.0 ± 32.4 AU(baseline) to 46.9 ± 45.9 AU (p = 0.022) followed by an insignificantand unstable course with high standard deviations.
Discussion
In our study, we showed that a cold atmospheric plasma (CAP) de-vice influencedmicrocirculation parameters in the intact skin of healthyvolunteers. Firstly, it improved cutaneous tissue oxygen saturation.Secondly, cutaneous blood flow was significantly upregulated, whilepostcapillary venous filling pressure remained non-significantly elevat-ed over themeasuring period. CAP triggeredmicrocirculatory effects fora period of approximately ten minutes after a single session applicationin the non-specific BMI group.
Two horizontal vascular networks connected by arterioles and ve-nules are the anatomical structures underlying cutaneousmicrocircula-tion. The subdermal plexus is situated at the dermal-subcutaneousborder, the dermal plexus is located 1–1.5 mm below the skin surface,depending on skin thickness (Braverman, 1997). These vascular net-works supply the skin with oxygen and nutrients. Since the proportionsof skin and fat can differ in the population,we excluded obese probands.Overweight (BMI up to 29.9) were not excluded, since overweight isprevalent in more than 60% of the population (Flegal et al., 2010). How-ever, we could show that the BMI strongly influences the effects of CAPon cutaneous microcirculation. Cutaneous tissue oxygen saturation inthe subgroup including participants with a BMI ≥ 25 showed a signifi-cant increase one minute after CAP application. Afterwards, it showedan elevated but insignificant trend for eight minutes. Postcapillary ve-nous filling pressure was not increased and cutaneous capillary bloodflow was exclusively enhanced one minute after the application. Onthe other hand, the subgroup including participants with a BMI b 25showed a significant increase in tissue oxygen saturation for ten mi-nutes, a significant increase of postcapillary venous filling pressurefromminute one after application until the end of themeasuring periodand a significant enhancement of capillary blood flow in the skin for tenminutes after CAP application. These results indicate that changes of cu-taneous microcirculation depend on the BMI. The group size of the
enous filling pressure in the non-specific BMI group (n= 20). After the application of CAPe 10 min later. 6 min later, cutaneous postcapillary venous filling pressure showed an up-ding participants with a BMI b 25 (n = 13) showed significant differences in cutaneousP application and showed a strongupward trendover the time. c. In contrast, the subgrouppressurewith high standard deviations. No significant differenceswere shown and a trend
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subgroup including participants with a BMI≥ 25 was a bit low, but dueto the high standard deviations differences to the subgroup includingparticipants with a BMI b 25 are obvious. These findings should beheeded in future studies.
In case of skin wounds, defects or inflammation, the capillary net-work is the site of cell adhesion, rolling and transmigration (Kubesand Kerfoot, 2001). Inadequate blood flow leads to the developmentof chronic wounds and an impaired immune response in the skin.Cold atmospheric plasma (CAP) has been shown to reduce pathogenson the skin (Brehmer et al., 2015) and improve wound healing (Isbaryet al., 2013; Heinlin et al., 2013) due to a release of chemically reactivespecies. In this context, chemically reactive species, such as ozone andphysically active ultraviolet radiation have proven their benefits indisinfection and inactivation of microorganisms (von Gunten, 2003;Hijnen et al., 2006). However, our findings indicate that other factorsproduced by CAP, such as nitric oxide (NO) or electric fields and cur-rents, may also play a major role in the effect of CAP on superficial softtissue. NO is typically produced by the cell's nitric oxide synthase(NOS) as an endogenous gas with various physiological effects, butit is also created in the field of CAP (Kartaschew et al., 2015; García-Alcantara et al., 2013; Heuer et al., 2015). NO acts as a vasodilator. Vaso-dilatation induced in this way can influence blood flow. Enhanced bloodflow correlates with shear stress and could therefore induce vascularnetwork formation (Galie et al., 2014). It has been shown that in diabet-ic patients with peripheral neuropathy NO production is decreased(Pitei et al., 1997). In this situation, micro- and macroangiopathy canimpair wound healing, especially in the lower legs. Moreover, oxygensaturation is a critical marker for tissue healing. Reduced oxygen supplyat a wound site can result in infections and impaired wound healing.Tissue oxygen saturation is known to be associated with skin tempera-ture, body mass index (BMI), age and even with blood flow (Kuligaet al., 2014). CAP enhanced cutaneous tissue oxygen saturation in ourstudy. Since patients characteristics were constant during the shortstudy period, other factors like blood flowmight have increased oxygensaturation. Blood flow showed a significant increase for 11 min, whiletissue oxygen saturation was elevated until 8 min after the application.Blood flow, however, increased again 14 and 19min after the treatment(28 min in the subgroup including participants with a BMI b 25), indi-cating that other factors than the short-life-cycle NO might play an im-portant role. The exact mechanism still remains unclear, but the cellularreactions on CAP are under recent investigation.
Cell behavior changes in response to CAP treatment. Arndt et al.showed that after 2 min of CAP application the expression of IL-8,TGF-b1/2 and b-defensin in keratinocyteswas induced, but no enhance-ment of proliferation or migration was seen (Arndt et al., 2015). On theother side, Haertel et al. could demonstrate that the use of DBD in-creased integrins in HaCaT keratinocytes if treatment time was longenough (N60 s). Integrins are surface adhesion molecules that are asso-ciatedwithwoundhealing due to adhesion and cell-matrix interactions.However, they did not find changes in E-cadherin and epithelial growthfactor receptor (EGFR) (Haertel et al., 2013). Epithelial cells seem toreact very sensitive, when treated with CAP. In an in vitro setting, mu-rine epithelial cells (mHepR1) lost their ability to adhere. And whentreatment time was extended, cell viability decreased (Hoentsch et al.,2012). Porcine aortic endothelial cells showed twice as much prolifera-tion associatedwith an enhanced fibroblast growth factor-2 (FGF-2) re-lease compared with untreated cells when CAP was used for 30 s.However, longer treatment time led to cell death in endothelial cells(Kalghatgi et al., 2010). In in vitro wound healing assays, improved
Fig. 3. a. Microcirculatory effects of cold atmospheric plasma (CAP) on cutaneous capillary blooblood flow increased by 73% and remained significantly elevated until 11min. Furthermore, a siwere nomore significant changes frombaseline. b. In the subgroup including participantswith aspecific BMI group. It rises very high 1 min after CAP and stayed elevated until 10 min later. Aftsubgroup including participants with a BMI≥ 25 (n= 7) showed a significant enhancement inchanges or tendencies were seen.
fibroblast cell migration was found after CAP application, but prolifera-tion was not enhanced.
In our setting, endothelial cell reactions could be of special interest.However, immediate reactions of these cells after CAP have neverbeen examined and should be investigated in further studies. In addi-tion, studies have to be conducted to evaluate microcirculatory, antimi-crobial and antifungal effects in human wounds that would especiallybenefit from these factors, such as burn wounds, infected wounds andchronic wounds. Focus should also be laid on diabetic patients, since ithas recently been shown that blood flow and tissue oxygen saturationare reduced in non-healing diabetic foot ulcers, while in healing ulcersblood flow is significantly higher (Beckert et al., 2004).Moreover, appli-cation time should be another target of further studies, since longer ex-posure is known to reduce bacterial load more effectively (Shimizuet al., 2011; Ermolaeva et al., 2011). Furthermore, immediate bacteriareduction in leg ulcers has been shown after a single use of CAP, butlater an increase in bacteria density was observed (Ulrich et al., 2015).In mice repetitive treatments significantly increased the rate of woundclosure (Ermolaeva et al., 2011; Nasruddin et al., 2014). Therefore, re-peated applications have to be investigated in future studies to deter-mine the impact on antimicrobial effects and wound healing indifferent types of humanwounds, also regarding patients with a higherBMI.
Conclusion
Cold atmospheric plasma increases cutaneous microcirculation pa-rameters. Tissue oxygen saturation is enhanced for 8 min after 90 s ofCAP application to the skin. Moreover, blood flow increased for 11 minafter the treatment, indicating that especially diabetic non-healingwounds might benefit from this treatment. However, further studiesare needed to better understand and optimize these effects.
Authors' contribution
Tobias Kisch was responsible for the acquisition and interpretationof data and wrote the manuscript. Andreas Helmke was involved inthe interpretation of data and in proofreading. Sophie Schleusser andJungin Song were responsible for acquisition and analysis of data. FelixHagen Stang, Eirini Liodaki and Peter Mailaender were involved in thestudy design and in paper writing. Robert Kraemer was responsiblefor the study design, data analysis and supervised all phases of thestudy.
Conflict of interest
Andreas Helmke was involved in the development of thePlasmaDerm® technology. The authors declare that no conflict ofinterest exists. Moreover, none of the authors has a financial inter-est in any of the devices mentioned in this study.
Acknowledgments
This study was funded by the University of Lübeck. This work wasnot funded by National Institute of Health (NIH),Wellcome Trust, How-ard Hughes Medical Institute (HHMI) or other institutes. The devicePlasmaDerm® was provided by Cinogy GmbH, respectively. No finan-cial or other support was given by the above mentioned company.
d flow in the non-specific BMI group (n= 20). One minute after the application capillarygnificant upregulation 14min and 19min post treatment was observed. Afterwards, thereBMI b 25 (n=13) the effect on cutaneous capillary bloodflowwas comparable to thenon-erwards no significant differences were seen except at 28 min after the application. c. Thecutaneous capillary blood flow 1min after CAP application. Afterwards, the effect nomore
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