Sabine Schanzer

Cutaneous concentration of lycopene correlates significantly with the roughness of the skin

Antioxidant substances in the skin are expected to slow down photo ageing. We therefore developed the hypothesis that high levels of antioxidant substances may be correlated to lower levels of skin roughness. By utilizing modern optical non-invasive in vivo methods, the structures of the furrows and wrinkles as well as the concentration of lycopene were analyzed quantitatively on the forehead skin of 20 volunteers aged between 40 and 50 years. In a first step, the age of the volunteers was correlated to their skin roughness. Here, no significant correlation was found. In a second step, a significant correlation was obtained between the skin roughness and the lycopene concentration (R=0.843). These findings indicate that higher levels of antioxidants in the skin effectively lead to lower levels of skin roughness, and therefore support our hypothesis.

Penetration and storage of particles in human skin: Perspectives and safety aspects

The application of particles in dermatology and cosmetology represents an emerging field and is closely connected with the question of risk assessment as the potential for, and consequences of, penetration of such particles into the living tissue has not been determined conclusively. In the medical sector, extensive research activities are in progress to develop particles, which can be used as efficient carriers for drug delivery through the skin barrier. In contrast, in cosmetic products, particles are mostly required to remain on the skin surface to fulfill their beneficial effect. Whereas the intercellular penetration of particles seems to be unlikely, the hair follicle has been shown to be a relevant penetration pathway for particles as well as an important long-term reservoir. It has been demonstrated that the penetration depth of the particles can be influenced by their size resulting in the possibility of a differentiated targeting of specific follicular structures. In the present review, the follicular penetration mechanisms and storage properties of particles are discussed.

In vivo skin treatment with tissue-tolerable plasma influences skin physiology and antioxidant profile in human stratum corneum.

Abstract:  The antimicrobial treatment of wounds is still a major problem. Tissue‐tolerable electrical plasma (TTP) is a new approach for topical microbial disinfection of the skin surface. The aim of the present study was to investigate the influence of TTP on a carotenoid profile in relation to skin physiology parameters (epidermal barrier function, stratum corneum (SC) hydration, surface temperature and irritation parameters). We were interested in the interaction of TTP and the antioxidative network, as well as the consequences for skin physiology parameters. These parameters are also indicative of TTP safety in vivo. For plasma application, ‘Kinpen 09’ was used (surface exposure 30–43°C) for 3 s. Beta‐carotene and water profiles were assessed by in vivo Raman microspectroscopy (skin composition analyzer 3510). Skin physiology parameters were measured with Tewameter TM 300, Corneometer CM 825, skin thermometer and Chromameter CR 300. All parameters were assessed non‐invasively on seven healthy volunteers before and after plasma application in vivo. We could show that TTP application leads to a decrease in beta‐carotene especially in the superficial SC. Skin‐surface temperature increased by 1.74°C, while the transepidermal water loss (TEWL) increase indicated an impaired barrier function. SC hydration decreased as seen in water profile especially in the superficial layers and capacitance values. A slight increase in skin redness was measurable. The induction of reactive oxygen species is probably the major contributor of TTP efficacy in skin disinfection. Skin physiology parameters were influenced without damaging the skin or skin functions, indicating the safety of TTP under in vivo conditions.

Interaction between Carotenoids and Free Radicals in Human Skin

Environmental factors like air pollutants, radiation of the sun and stress factors such as illness, smoking, or alcohol abuse produce free radicals in the human tissue as well as in the skin. Free radicals serve as the main cause for premature skin aging. Additionally, they also contribute towards immunosuppression and the formation of skin diseases including cancer. The human organism has developed a protection system against the destructive action of free radicals by means of the antioxidant network. In the present study, the interaction of free radicals and carotenoid antioxidants in the human skin under in vivo conditions was investigated and summarized. The measurement of carotenoids in human skin was performed in vivo using resonance Raman spectroscopy.

In vivo investigations on the penetration of various oils and their influence on the skin barrier

The skin represents a potent barrier to the environment, which can be enhanced by the topical application of skin care products, such as oil and oil‐based formulations by moisturizing the skin.

Sunscreen application at the beach

Background  The sun protection factor (SPF) of sunscreens is determined after application of a standard amount. The European Cosmetic Toiletry and Perfumery Association (COLIPA) standard amount is 2 mg/cm2. Real‐life application of sunscreen is probably less than this.

In vivo photoprotective and anti-inflammatory effect of hyperforin is associated with high antioxidant activity in vitro and ex vivo.

Hyperforin, a major constituent of St. Johns Wort (Hypericum perforatum, HP), provides anti-inflammatory, anti-tumor, and anti-bacterial properties. Previous studies have shown anti-oxidative properties of St. Johns Wort extracts; however, its free radical scavenging activity in skin cells or skin has not been assessed in detail so far. Therefore, the free radical scavenging activity of hyperforin was tested in the H(2)DCFDA-assay in vitro in HaCaT keratinocytes irradiated with solar simulated radiation. Hyperforin (EC(50) 0.7 μM corresponding to 0.42 μg/ml) was much more effective compared to Trolox (EC(50) 12 μg/ml) and N-acetylcysteine (EC(50) 847 μg/ml) without showing phototoxicity. The radical protection factor of a cream containing 1.5%w/w of a hyperforin-rich HP extract was determined to be 200 × 10(14) radicals/mg, indicating a high radical scavenging activity. The cream was further applied ex vivo on porcine ear skin and significantly reduced radical formation after infrared irradiation. Finally, the UV-protective effect of the HP cream was tested on 20 volunteers in a randomized, double-blind, vehicle-controlled study. HP cream significantly reduced UVB-induced erythema as opposed to the vehicle. Occlusive application of HP cream on non-irradiated test sites did not cause any skin irritation. Taken together, these results demonstrate that hyperforin is a powerful free radical scavenger.

Optical investigations to avoid the disturbing influences of furrows and wrinkles quantifying penetration of drugs and cosmetics into the skin by tape stripping

Furrows and wrinkles, as typical structures of human skin, represent a reservoir for topically applied substances. This reservoir can influence penetration experiments of topically applied substances into the stratum corneum by tape stripping. Optical methods such as laser-scanning microscopy, optical coherent tomography, and the microscopical investigation of histological sections obtained by biopsies were used to check a special protocol, which avoids these potential disturbances. The use of a transparent adhesive film with high flexibility and the realization of an intense contact to the stretched skin by pressing the tape with a roll, moved laterally on the tape, are the prerequisites to obtain correct data. The application of this experimental technique and the performance of tape stripping allow the determination of the horny layer profile and the local distribution of topically applied substance, undisturbed by the characteristic structure of the natural skin. These results demonstrate that the presented tape stripping procedure is a valuable tool to determine, quantitatively, the penetration and the bioavailability of drugs and cosmetics inside the human stratum corneum, in relation to the horny layer profile.

Comparison of the Antiseptic Efficacy of Tissue-Tolerable Plasma and an Octenidine Hydrochloride-Based Wound Antiseptic on Human Skin

Colonization and infection of wounds represent a major reason for the impairment of tissue repair. Recently, it has been reported that tissue-tolerable plasma (TTP) is highly efficient in the reduction of the bacterial load of the skin. In the present study, the antiseptic efficacy of TTP was compared to that of octenidine hydrochloride with 2-phenoxyethanol. Both antiseptic methods proved to be highly efficient. Cutaneous treatment of the skin with octenidine hydrochloride and 2-phenoxyethanol leads to a 99% elimination of the bacteria, and 74% elimination is achieved by TTP treatment. Technical challenges with an early prototype TTP device could be held responsible for the slightly reduced antiseptic properties of TTP, compared to a standard antiseptic solution, since the manual treatment of the skin surface with a small beam of the TTP device might have led to an incomplete coverage of the treated area.

Comparison of Transepidermal Water Loss and Spectroscopic Absorbance to Quantify Changes of the Stratum corneum after Tape Stripping

The objective and quantitative application of tape stripping in pharmaceutics and dermatopharmacokinetics requires the determination of the exact position of each removed tape strip inside the stratum corneum (SC) and/or the determination of the relative SC thickness. In this study, transepidermal water loss (TEWL) and the optical spectroscopic data of the corneocytes were measured simultaneously during the complete removal of the SC by tape stripping. The spectroscopic data quantitatively reflect the amount of corneocytes removed by the individual tape strips, whereas TEWL and 1/TEWL are not sensitive enough to measure the relatively small changes in the SC thickness realized by the removal of the individual strips. The relative SC thickness can be determined directly by the spectroscopic data, while the 1/TEWL values require a second independent method. The results demonstrate the importance of tape stripping characterizing the behaviour of topically applied substances.