Relations between the Raman spectra and molecular structure of selected carotenoids: DFT study of α-carotene, ß-carotene, γ-carotene and lycopene.

Using the density functional theory (DFT), we calculated the structures and Raman spectra of trans-isomers of α-carotene, ß-carotene, γ-carotene and lycopene as well as trans-isomers of modified ß-carotene and lycopene molecules with substituted end or/and side groups. The DFT calculations showed that the position of the CC stretching band depends mainly on the number of conjugated CC bonds and decreases with an increase in the conjugation length. The weak dependence of the position of the CC stretching band on the structure of the carotenoid side and end groups suggests that this band can be used to evaluate the conjugation length for trans-isomers of various molecules containing polyene chains. The CC stretching band shifts towards lower wavenumbers with growth of the conjugation length or masses of the end groups and to higher wavenumbers in the presence of the side CH3 groups. The intensities of the CC and CC stretching bands are enhanced with growth of the conjugation length or masses of the end groups. The presence of the side CH3 groups results in bending of the carotenoid backbone, splitting and dumping of intensities of the CC and CC stretching bands.

Influence of nanocrystal size on the in vivo absorption kinetics of caffeine after topical application.

The absorption of topically applied substances is challenging due to the effective skin barrier. Encapsulation of substances into nanoparticles was expected to be promising to increase the bioavailability of topically applied products. Since nanoparticles cannot traverse the intact skin barrier, but penetrate into the hair follicles, they could be used to deliver substances via hair follicles, where the active is released and can translocate independently transfollicularly into the viable epidermis. In the present in vivo study, this effect was investigated for caffeine. Caffeine nanocrystals of two sizes, 206 nm and 694 nm, with equal amounts of caffeine were used to study caffeine serum concentration kinetics after topical application on 5 human volunteers. The study demonstrated that at early time points, the smaller nanocrystals were more effective in increasing the bioavailability of caffeine, whereas after 20 min, the serum concentration of caffeine was higher when caffeine was applied by larger nanocrystals. Caffeine was still detectable after 5 days. The area under the curve could be increased by 82% when the 694 nm nanocrystals were applied. Especially larger sized nanocrystals seem to be a promising type of nanoparticulate preparation to increase the bioavailability of topically applied drugs via the transfollicular penetration pathway.

Blind source separation of molecular components of the human skin in vivo: non-negative matrix factorization of Raman microspectroscopy data.

Determination of the molecular composition of the skin is crucial for numerous tasks in medicine, pharmacology, dermatology and cosmetology. Confocal Raman microspectroscopy is a sensitive method for the evaluation of molecular depth profiles in the skin in vivo. Since the Raman spectra of most of the skin constituents significantly superimpose, a spectral decomposition by a set of predefined library components is usually performed to disentangle their contributions. However, the incorrect choice of the number and type of components or differences between the spectra of the basic components measured in vitro and in vivo can lead to incorrect results of the decomposition procedure. Here, we investigate an alternative data-driven approach based on a non-negative matrix factorization (NNMF) algorithm of depth-resolved Raman spectra of skin that does not require a priori information of spectral data for the analysis. Using the model and experimentally measured depth-resolved Raman spectra of the upper epidermis in vivo, we show that NNMF provides depth profiles of endogenous molecular components and exogenous agents penetrating through the upper epidermis for the spectra and concentration. Moreover, we demonstrate that this approach is capable of providing new information on the molecular profiles of the skin.

DFT study of Raman spectra of polyenes and ß-carotene: Dependence on length of polyene chain and isomer type.

We carried out calculations of non-resonance Raman spectra of ß-carotene and polyenes CH2(CHCH)n-2CHCH2 using the density functional theory (DFT). We revealed that the peak positions and intensities of the CC and CC stretching bands depend on length of the polyene chain and type of the isomer. Our experimental non-resonance Raman spectra of ß-carotene powder match well the DFT-simulated Raman spectrum of ß-carotene in the all-trans form. The peak positions and relative intensities of the CC and CC stretching bands of ß-carotene turned out to be similar in the resonance and non-resonance Raman spectra. An increase in the number of conjugated double bonds (n = 3-30) in a polyene structure results in a monotonous shift of the positions of the most intense CC and CC bands towards lower wavenumbers with an increase in the band intensities. An increase in the isomer number results in the monotonous decrease of the CC stretching band intensity for polyenes with 9, 10, 11, 15 and 24 double bonds. An increase in the isomer number inhomogeneously influences the form, position and intensity of the CC stretching band.

Characterization of radical types, penetration profile and distribution pattern of the topically applied photosensitizer THPTS in porcine skin ex vivo.

The topical photodynamic therapy (PDT) is mainly used in the treatment of dermato-oncological diseases. The distribution and functionality of the photosensitizer Tetrahydroporphyrin-Tetratosylat (THPTS) was investigated using microscopic and spectroscopic methods after topical application to excised porcine skin followed by irradiation. The distribution of THPTS was determined by two-photon tomography combined with fluorescence lifetime imaging (TPT/FLIM) and confocal Raman microspectroscopy (CRM). The radicals were quantified and characterized by electron paramagnetic resonance (EPR) spectroscopy. Results show a penetration depth of THPTS into the skin down to around 12 ± 5 µm. A penetration of THPTS through the stratum corneum was not clearly observable after 1 h penetration time, but cannot be excluded. The irradiation within the phototherapeutic window (spectral range of visible and near infrared light in the range ≈ 650-850 nm) is needed to activate THPTS. An incubation time of 10 min showed the highest radical production. A longer incubation time affected the functionality of THPTS, whereby significant less radicals were detectable. During PDT mainly reactive oxygen species (ROS) and lipid oxygen species (LOS) are produced. Overall, the irradiation dose per se influences the radical types formed in skin. While ROS are always prominent at low doses, LOS increase at high doses, independent of previous skin treatment and the irradiation wavelength used.

Influence of physical-mechanical properties on SPF in sunscreen formulations on ex vivo and in vivo skin.

The sun protection factor (SPF) is related to the selected UV filters. The objective of this study was to evaluate and compare the rheological behavior and texture profile of two sunscreen formulations and to correlate these data with the obtained SPF values. Two formulations (F1 and F2) were developed with the same type and amount of UV filters - whereby one of them also contained ethoxylated lanolin as additional film former (F2). Their rheological behavior, texture profile and in vitro and in vivo SPF were analyzed. The film-forming properties were evaluated by skin profilometry and diffuse reflectance spectroscopy. The structures of the formulations were examined by two-photon tomography combined with fluorescence lifetime imaging, and the penetration profile into the stratum corneum was investigated by tape stripping. The formulation with lanolin presented lower and constant values for physical-mechanical parameters, with a higher and better reproducible SPF. Both formulations did not penetrate the viable epidermis. In conclusion, formulations with better surface deposition on the skin surface can influence the film formation and, consequently, improve the SPF. These findings are important to improve the efficacy of sunscreen formulations and reduce the addition of UV filters.

Switching from healthy to unhealthy oxidative stress - does the radical type can be used as an indicator?

Ultraviolet (UV) radiation leads to the formation of free radicals, which may cause immunological modulations, skin aging or skin cancer. Sunlight exposure in the UVA region according to CIE 85 promotes almost 46% of radical formation in skin. A critical radical concentration characterized by the inversion of the domination of primary ROS (reactive oxygen species) to an excess of secondary LOS (lipid oxygen species) is proven for the spectral regions UV and or VIS light and is intended to be a marker for an imbalance in the redox system, which can no longer compensate harmful effects. To investigate whether this transition point is also universally valid for one spectral region, the radical formation during and after targeted UVA in situ-irradiation at 365 ± 5 nm and three different irradiances (31, 94 and 244 mW/cm2) was investigated in ex vivo porcine skin using x-band electron paramagnetic resonance (EPR) spectroscopy. The quantification was performed with the spin probe 3-(carboxy)-2,2,5,5-tetramethylpyrrolidin-1-oxyl (PCA), the spin trap 5,5-Dimethyl-1-Pyrroline-N-Oxide (DMPO) was used to characterize the radical species. Furthermore, the viability of the skin cells after irradiation was controlled by an MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, skin integrity was examined by histological analysis. A significant dose dependence in the radical formation is given at higher irradiance. The transition point was detected in the range of 0.5 MED after irradiation with the highest irradiance. From this point on the proportion of LOS increases with increasing dose and the proportion of ROS decreases. After switching off the UVA irradiation no further quantitative changes were detected, but rapid changes in the radical pattern were observed demonstrating the importance of in situ irradiation during the use of spin traps. Heat-pre-stressed skin showed more LOS than ROS already at the beginning of the irradiation, leading to the assumption that the transition point to the distress-level has already been reached. In summary, a postulated transition point could be verified for the UVA spectral region using only one spin trap combined with in-situ irradiation. A certain degree of stress is necessary to detect an inversion of the ratio of ROS to LOS. This reversal indicates an imbalance in the redox status. However, at low intensities no changes at all in radical pattern appeared over time (dose), probably it can be compensated by adaptation processes of the skin.

Stratum corneum occlusion induces water transformation towards lower bonding state: a molecular level in vivo study by confocal Raman microspectroscopy.

OBJECTIVE: It is conventionally understood that occlusive effects are the retention of excessive water in the stratum corneum (SC), the increase of SC thickness (swelling) and a decrease of the transepidermal water loss. However, the influence of occlusion on water binding properties in the SC is unknown. METHODS: The action of plant-derived jojoba and almond oils, as well as mineral-derived paraffin oil and petrolatum topically applied on human skin, is investigated in vivo using confocal Raman microspectroscopy. To understand the oils' influence on the SC on the molecular level, the depth-dependent hydrogen bonding states of water in the SC and their relationship to the conformation of keratin, concentration of natural moisturizing factor (NMF) molecules and lipid organization were investigated. RESULTS: A significant SC swelling was observed only in petrolatum-treated skin. The water concentration was increased in oil-treated skin in the intermediate SC region (40-70% SC depth). Meanwhile, the amount of free, weakly and tightly bound water increased, and strongly bound water decreased in the uppermost SC region (0-30% SC depth). The NMF concentration of oil-treated skin was significantly lower at 50-70% SC depth. The lateral organization of lipids in oil-treated skin was lower at 0-30% SC depth. The secondary structure of keratin was changed towards an increase of ß-sheet content in mineral-derived oil-treated skin and changed towards an increase of α-helix content in plant-derived oil-treated skin. CONCLUSION: The occlusive properties can be summarized as the increase of free water and the transformation of water from a more strongly to a more weakly hydrogen bonding state in the uppermost SC, although some oils cause insignificant changes of the SC thickness. The accompanied changes in the keratin conformation at the intermediate swelling region of the SC also emphasize the role of keratin in the SC's water-transporting system, that is the water in the SC transports intercellularly and intracellularly in the intermediate swelling region and only intercellularly in the uppermost non-swelling region. Bearing this in mind, almond, jojoba and paraffin oils, which are not occlusive from the conventional viewpoint, have an occlusion effect similar to petrolatum on the SC.

OBJECTIF: Il est généralement entendu que les effets occlusifs consistent en la rétention d'un excès d'eau dans la couche cornée (stratum corneum, SC), l'augmentation d'épaisseur de la SC (gonflement) et une diminution de la perte d'eau trans-épidermique. Cependant, l'influence de l'occlusion sur les propriétés de fixation de l'eau dans le SC est inconnue. MÉTHODES: L'action des huiles de jojoba et d'amande d'origine végétale, ainsi que des huiles de paraffine et de pétrolatum d'origine minérale appliquées topiquement sur la peau humaine est étudiée in vivo à l'aide de la microspectroscopie Raman confocale. Pour comprendre l'influence des huiles sur le SC au niveau moléculaire, on a étudié les états de liaison hydrogène de l'eau dans le SC en fonction de la profondeur et leur relation avec la conformation de la kératine, la concentration des molécules du facteur naturel d'hydratation (NMF) et l'organisation des lipides. RÉSULTATS: Un gonflement significatif de le SC n'a été observé que dans la peau traitée au pétrolatum. La concentration en eau a été augmentée dans la peau traitée au pétrolatum dans la région SC intermédiaire (40-70% de profondeur du SC). En meme temps, la quantité d'eau libre, faiblement et fortement liée augmentait, tandis que l'eau fortement liée diminuait dans la région SC supérieure (0-30% de profondeur du SC). La concentration en NMF de la peau traitée à l'huile était plus basse d´une manière significative à 50-70% de profondeur du SC. L'organisation latérale des lipides dans la peau huilée était plus basse à une profondeur du SC de 0 à 30 %. La structure secondaire de la kératine a été modifiée pour augmenter la teneur en feuillet-ß dans les peaux huilées d'origine minérale et pour augmenter la teneur en hélice α dans les peaux huilées d'origine végétale. CONCLUSION: Les propriétés occlusives peuvent être résumées comme l'augmentation de l'eau libre et la transformation de l'eau d'un état de liaison hydrogène plus fort à un état de liaison hydrogène plus faible dans le SC supérieure, bien que certaines huiles provoquent des changements insignifiants de l'épaisseur de la SC. Les modifications de la conformation de la kératine dans la zone de gonflement intermédiaire du SC soulignent également le rôle de la kératine dans le système de transport de l'eau du SC, c'est-à-dire que l'eau est transportée du SC de manière intercellulaire et intracellulaire dans la zone de gonflement intermédiaire et seulement de manière intercellulaire dans la zone non gonflée la plus élevée. En considérant cela, les huiles d'amande, de jojoba et de paraffine, qui ne sont pas occlusives du point de vue conventionnel, ont un effet d'occlusion similaire à celui du pétrolatum sur le SC.

Label-Free Multiphoton Microscopy: The Origin of Fluorophores and Capabilities for Analyzing Biochemical Processes.

Multiphoton microscopy (MPM) is a method of molecular imaging and specifically of intravital imaging that is characterized by high spatial resolution in combination with a greater depth of penetration into the tissue. MPM is a multimodal method based on detection of nonlinear optical signals - multiphoton fluorescence and optical harmonics - and also allows imaging with the use of the parameters of fluorescence decay kinetics. This review describes and discusses photophysical processes within major reporter molecules used in MPM with endogenous contrasts and summarizes several modern experiments that illustrate the capabilities of label-free MPM for molecular imaging of biochemical processes in connective tissue and cells.

Methods for Optical Skin Clearing in Molecular Optical Imaging in Dermatology.

This short review describes recent progress in using optical clearing (OC) technique in skin studies. Optical clearing is an efficient tool for enhancing the probing depth and data quality in multiphoton microscopy and Raman spectroscopy. Here, we discuss the main mechanisms of OC, its safety, advantages, and limitations. The data on the OC effect on the skin water content are presented. It was demonstrated that 70% glycerol and 100% OmnipaqueTM 300 reduce the water content in the skin. Both OC agents (OCAs) significantly affect the strongly bound and weakly bound water. However, OmnipaqueTM 300 causes considerably less skin dehydration than glycerol. In addition, the results of examination of the OC effect on autofluorescence in two-photon excitation and background fluorescence in Raman scattering at different skin depths are presented. It is shown that OmnipaqueTM 300 is a promising OCA due to its ability to reduce background fluorescence in the upper skin layers. The possibility of multimodal imaging combining optical methods and OC technique is discussed.

[Follicular penetration of nanocarriers is an important penetration pathway for topically applied drugs]. / Bedeutung des follikulären Penetrationswegs für den Wirkstofftransport mittels Nanocarriern.

BACKGROUND: The hair follicle represents a significant penetration route for topically applied substances. ISSUE: The percutaneous absorption of substances can be significantly increased and accelerated by the involvement of hair follicles. In addition, nanoparticles have the characteristic to penetrate deeply and effectively into the hair follicles. MATERIALS AND METHODS: An optimization of drug delivery for topically applied substances is possible if the nanoparticles act solely as a carrier to transport active ingredients into the hair follicle. Once the nanocarrier has penetrated into the hair follicle, the active substance must be released there. This can be triggered by various mechanisms. RESULTS: The released drug can thus pass into the living tissue surrounding the hair follicle independently. With the help of this innovative strategy, the bioavailability of topically applied substances can be significantly improved. CONCLUSION: The transport of active ingredients into the hair follicles with the help of particles and the release of active substances there is a very effective new method for transporting active substances through the skin barrier.

Multiphotonic staging of chronic wounds and evaluation of sterile, optical transparent bacterial nanocellulose covering: A diagnostic window into human skin.

BACKGROUND: Diagnostics of healing, infection, and inflammation in chronic wounds in comparison with physiological wound healing in acute wounds may help for therapy decisions toward individualized therapy management. With emerging new optical techniques the coupling of optical diagnostic devices with tissue provides a great challenge. Traditional coupling with cover slips is used since the early days of microscopy. In modern health care, hygienic covering of surfaces is necessary to avoid infections and cross-contaminations. METHODS: Measurements in chronic wounds were performed at three different areas including the center of the wound, the border of the wound and healthy skin as comparison area. For each measurement area, three vertical stacks were taken by MPT. Additionally, three different optical measuring procedures (MPT, OCT, CLSM) were used for the examination of BNC foil. Examinations of BNC foil were carried out at two different areas of healthy skin compared to a standard setup as control. RESULTS: The MPT evaluation revealed a distinct difference in the second harmonic generation-to-autofluorescence aging index of dermis (SAAID) behavior between the vertical stacks taken at central wound areas and wound margins as well as unaffected skin. Through BNC foil covers, MPT CLSM and OCT images were captured with good quantitative and qualitative results. CONCLUSIONS: Phases in chronic wounds could be matched with physiologically healing in acute wounds according to SAAID and MPT imaging. BNC provided an alternative covering for MPT, OCT, and CLSM with clear morphological images.

Kinetics and tissue repair process following fractional bipolar radiofrequency treatment.

INTRODUCTION: Fractionated radiofrequency (RF) tissue tightening is an alternative method to fractionated laser treatment of skin wrinkling, laxity and acne scars, with reduced risk of scarring or persistent pigmentation. The aim of this study was to evaluate and quantify the wound healing process after RF treatment. MATERIALS AND METHODS: 12 patients were treated with a 64-pin fractional bipolar RF device with 60 mJ/pin applied energy. Confocal laser scanning microscopy (CLSM) examination was performed on day 1, day 2, day 7 and day 14 after treatment. Clinical wound healing process was measured and expressed as a percentage. RESULTS: All patients developed erythema, mild edema and crusts at the treated areas. Two weeks after treatment clinical symptoms resolved. During ablation patients reported moderate pain. Directly after ablation microscopic ablation zones could be detected in CLSM. Measurement of MAZ at epidermis, dermo-epidermal junction and papilary dermis showed a constant diameter until two weeks after treatment. Re-epithelization of the MAZ could be detected already 1 week after treatment. However, 2 weeks after ablation the honeycomb pattern of the epidermis was not yet completely restored. DISCUSSION: Bipolar fractionated RF treatment demonstrates clinically a rapid wound healing response. The subepidermal remodelling process still ongoing after 14 days, showing new granulation tissue. Therefore, treatment intervals of at least 14 days should be recommended to allow completion of the remodelling process.

Skin type differences in solar-simulated radiation-induced oxidative stress.

BACKGROUND: Human skin protects the body from external damage, pathogens and oxidative stress factors such as ultraviolet (UV) radiation. Excessive exposure to UV radiation can lead to increased production of free radicals and hence to skin damage such as inflammation, premature skin ageing and skin cancer. Besides UV, the visible and near infrared (NIR) regions are also a source of radical production. Half of all free radicals are induced by the visible + NIR region of the solar spectrum in people with skin types I-III, but data on the effects in people with skin types IV-VI are missing. OBJECTIVES: This in vivo pilot study addressed the distribution of radical production in skin types IV and V during irradiation in the UV, visible and NIR spectral regions, comparing the first results with those of skin type II. METHODS: The measurements were performed in vivo using L-band electron paramagnetic resonance spectroscopy and the spin probe PCA. RESULTS: In skin types IV-V most radicals were induced in the visible + NIR region, followed by the NIR and UV regions of the sun spectrum. Significantly (P ≤ 0·05) more radicals were induced in skin types IV-V than in type II during NIR irradiation, whereas skin types IV-V exhibited significantly less UV-induced radicals (P ≤ 0·01) than skin type II. CONCLUSIONS: All spectral regions (UV, visible and NIR) cause free radical formation in skin types II and IV-V. After 4 min of solar-simulated exposure (UV-NIR), the radical formation in skin types IV-V is 60% of that in skin type II. Therefore people with darker skin types also need solar protection.

Multicenter methodology comparison of the FDA and ISO standard for measurement of in vitro UVA protection of sunscreen products.

In vitro standard methods are available and accepted worldwide to assess UVA protection of sunscreen products. Though, harmonisation of methods has made progress in the last decade, still two differing methods - one by FDA the other by ISO - are in use. In a multicentre study including 9 centres in Germany, 4 different commercial sunscreen products were assessed using both methods to discover their similarities and differences. UVA protection factor and Critical Wavelength were detected at various substrate type (sandblasted versus moulded PMMA plates), at different surface roughness of the plates as well as at different product application dose using two different irradiation spectra. Results: The strongest influence on UVA protection factor results from the surface roughness of the plates. Depending on the roughness (accepted range of 2 to 7 µm in the FDA method) a variability in the UVA protection factor of up to 25% was observed, while the much narrower definition of plate roughness by ISO (4.5 to 5.2 µm) had no relevant influence on the test results. Sandblasted plates in our assessment led to higher UVA protection factors and produced less scattered results compared to moulded plates. These differences were not pronounced. Application dose and spectra of the irradiation source were of negligible influence on UVA protection factor results for the investigated UV-filter combinations. The UVA protection factor which is the endpoint of the ISO method was found to be a parameter with a high potential to differentiate among different test products. The endpoint of the FDA method - the Critical Wavelength - was found to be an unambitious endpoint. Insensitivity to all described modifications of the method was observed. All investigated products performed similar and passed the Critical Wavelength criteria independent of method and parameters.

Recent progress in tissue optical clearing for spectroscopic application.

This paper aims to review recent progress in optical clearing of the skin and over naturally turbid biological tissues and blood using this technique in vivo and in vitro with multiphoton microscopy, confocal Raman microscopy, confocal microscopy, NIR spectroscopy, optical coherence tomography, and laser speckle contrast imaging. Basic principles of the technique, its safety, advantages and limitations are discussed. The application of optical clearing agent on a tissue allows for controlling the optical properties of tissue. Optical clearing-induced reduction of tissue scattering significantly facilitates the observation of deep-located tissue regions, at the same time improving the resolution and image contrast for a variety of optical imaging methods suitable for clinical applications, such as diagnostics and laser treatment of skin diseases, mucosal tumor imaging, laser disruption of pathological abnormalities, etc.

Non-invasive evaluation of human mucosal structures by multiphoton laser scanning tomography in vitro.

BACKGROUND: Mucous membranes may be affected by various diseases and the diagnostic accessibility is limited. Multiphoton laser tomography (MPT) is a useful tool for in vivo evaluation of superficial skin structures and might also be useful for the imaging of mucosa. OBJECTIVES: In order to investigate the suitability of MPT for the evaluation of mucous membranes, tissue samples of different donors and anatomical localizations have been imaged. METHODS: Human mucosa samples from the urinary bladder, palatine tonsil and ocular conjunctiva were investigated by MPT and subsequently compared with conventional histology. RESULTS: Horizontal images of the epithelium and the underlying connective tissue were obtained using the autofluorescence and second harmonics generation signals by MPT. The stratification of multilayered epithelium was consistently reproduced. Also inflammatory changes like lymphocytic infiltrates and widened intercellular spaces were imaged in some cases. CONCLUSION: Mucous tissue samples were obtained and MPT imaging was successfully performed. In the direct comparison with histology of the same tissue samples, the characteristic morphology of the epithelia was found. Further studies are necessary in order to compare images of healthy and diseased mucosal epithelium and the use of MPT for its evaluation in vivo.

EPR Technology as Sensitive Method for Oxidative Stress Detection in Primary and Secondary Keratinocytes Induced by Two Selected Nanoparticles.

Exogenous factors can cause an imbalance in the redox state of biological systems, promoting the development of oxidative stress, especially reactive oxygen species (ROS). To monitor the intensity of ROS production in secondary keratinocytes (HaCaT) by diesel exhaust particles and thermoresponsive nanogels (tNG), electron paramagnetic resonance (EPR) spectroscopy after 1 and 24 h of incubation, respectively, was applied. Their cytotoxicity was analyzed by a cell viability assay (XTT). For tNG an increase in the cell viability and ROS production of 10% was visible after 24 h, whereas 1 h showed no effect. A ten times lower concentration of diesel exhaust particles exhibited no significant toxic effects on HaCaT cells for both incubation times, thus normal adult human keratinocytes (NHK) were additionally analyzed by XTT and EPR spectroscopy. Here, after 24 h a slight increase of 18% in metabolic activity was observed. However, this effect could not be explained by the ROS formation. A slight increase in the ROS production was only visible after 1 h of incubation time for HaCaT (9%) and NHK (14%).

Prevention of palmoplantar erythrodysesthesia in patients treated with pegylated liposomal doxorubicin (Caelyx®).

PURPOSE: Palmoplantar erythrodysesthesia (PPE) is one of the most frequent side effects during systemic treatment with pegylated liposomal doxorubicin (PLD, Caelyx®). PPE lesions show a range of symptoms, from numbness to painful erosions, and can have a major impact on the quality of life in affected patients. Previously, a possible pathomechanism of PPE was found in doxorubicin-treated patients based on radical formation in the skin. Here, a preventive strategy using a topically applied ointment with a high radical protection factor was investigated. METHODS: In this randomized placebo-controlled double-blind study the antioxidant-containing ointment was compared with a placebo ointment regarding PPE grade III occurrence, overall PPE grade I-III occurrence and PPE severity in PLD patients. The verum or placebo cream was topically applied for a period of 16 weeks, starting 3 days prior to the first cycle of chemotherapy. Clinical evaluations were carried out by a dermatologist prior to the first cycle of chemotherapy and every 4 weeks for the duration of 16 weeks. RESULTS: Thirty-two patients were enrolled in total, of which 17 (66%) completed the study. No PPE grade III was found in the verum group, while five out of seven patients (71%) had to be unblinded in the placebo arm due to PPE grade III (p = 0.003). General PPE occurrence of all grades was 60% under verum and 86% under placebo treatment. CONCLUSIONS: The preventive application of an antioxidant-containing ointment was shown to be significantly more effective in the prevention of PPE grade III compared to placebo treatment.