The impact of skin massage frequency on the intrafollicular transport of silica nanoparticles: Validation of the ratchet effect on an ex vivo porcine skin model.

The human hair follicle (HF) represents a promising drug delivery target as an anatomical entity by itself, but also as a gateway enabling dermal or systemic bioavailability of active cosmetic and pharmaceutical ingredients. Due to its morphological characteristics, the HF provides a mechanically driven transport process of nanoparticles (NPs) when external forces are applied. This mechanism was presented as the so-called ratchet effect within the framework of an in silico study published recently. To investigate the influence of massage frequency on the penetration depth of NPs, and, by this, to validate the results obtained in silico, we implemented a corresponding application protocol on an ex vivo porcine skin model. In this connection, we compared three different skin massage frequencies (4.2 Hz, 50 Hz, 100 Hz) for the topical application of cyanine 5-labeled silica NPs (Cy5-SNPs). To elucidate the interplay of frequency and particle size, we furthermore applied Cy5-SNPs of three different diameters (300 nm, 676 nm, 1000 nm). Confocal laser scanning microscopy was utilized to investigate the follicular penetration depth of Cy5-SNPs on cryohistological slices. By this, we could demonstrate that the massage frequency and the follicular penetration depth exhibit an inverse relation pattern. Thus, the highest follicular penetration depth was observed within the 4.2 Hz group, while the lowest follicular penetration depth was found within the 100 Hz group for each Cy5-SNP size category. Additionally, we found that 676 nm Cy5-SNPs penetrated significantly deeper into HFs than 300 nm Cy5-SNPs and 1000 nm Cy5-SNPs, respectively. Summarizing, our results show that a low massage frequency including a dominant radial direction component leads to deeper follicular penetration depths of NPs than automated 3D-oscillation massage at 50 Hz or 100 Hz. Thus, our findings are in line with recent in silico results. Regarding translational purposes, our results are of high interest, since a massage executed at 250BPM (4.2 Hz) is within a realizable range for manual application, e.g. for the implementation into clinical routines or the domestic use of drugs or cosmetics. Furthermore, the application of different massage frequencies offers the opportunity of patho-specific targeting as different anatomical parts of the HF can be reached.

Laser Scanning Microscopic Investigations of the Decontamination of Soot Nanoparticles from the Skin.

BACKGROUND/AIMS: Airborne pollutants, such as nano-sized soot particles, are increasingly being released into the environment as a result of growing population densities and industrialization. They can absorb organic and metal compounds with potential biological activity, such as polycyclic aromatic hydrocarbons and airborne pollen allergens. Local and systemic toxicities may be induced in the skin if the particulates release their harmful components upon dermal contact. METHODS: In the present study, skin pretreatments with serum and/or shield as barrier formulations prior to exposure and washing with a cleanser subsequent to exposure were evaluated as a protection and decontamination strategy using laser scanning microscopy. RESULTS: The results indicate that while the application of serum and a cleanser was insufficient for decontamination, the pretreatment with shield prior to nanoparticle exposure followed by washing led to the removal of a considerable amount of the carbon black particles. The combined application of serum and shield before the administration of carbon black particles and subsequent washing led to their elimination from the skin samples. CONCLUSION: The application of barrier-enhancing formulations in combination with a cleanser may reduce the penetration of harmful airborne particulates by preventing their adhesion to the skin and facilitating their removal by subsequent washing with the cleanser.

Prevention of Cutaneous Penetration and CD1c+ Uptake of Pollen Allergens by a Barrier-Enhancing Formulation.

Recent studies have shown that pollen proteins can penetrate the impaired skin barrier of atopic patients and exacerbate their disease. In the presented study the effect of a topically applied barrier-enhancing formulation was investigated for its preventive effect on the uptake of pollen allergens into CD1c+ epidermal cells. The pollen proteins were fluorescence labelled and applied on barrier-disrupted excised human skin. CD1c+ cells were selected after magnetic cell sorting and analysed using laser scanning microscopy. In untreated disrupted skin, 81% of the CD1c+ cells contained the fluorescence-labelled pollen allergens. In formulation-pretreated skin only 12% of the CD1c+ cells showed an uptake of pollen allergens. These results encourage the treatment of atopic patients with barrier-enhancing formulations to reduce the impact of pollen on air-exposed skin areas and hence the exacerbation of cutaneous symptoms.

Relationship between Histological and Clinical Course of Psoriasis: A Pilot Investigation by Reflectance Confocal Microscopy during Goeckerman Treatment.

Alterations of the skin microvasculature are known to play an important role in the development and maintenance of psoriatic skin lesions. In this study, we investigated lesional skin in 11 psoriatic patients during a modified Goeckerman treatment using reflectance confocal microscopy (RCM) to study the relationship between clinical clearance and histological normalization of psoriatic skin and the significance of histological abnormalities on the course of disease. The treatment regimen resulted in a significant reduction of the Psoriasis Area and Severity Index (PASI) as well as capillary and papillary diameters (p < 0.0001). The capillary and papillary diameters were still enlarged when compared to those in normal skin (p < 0.001). Capillary and papillary diameters correlated with each other prior to and after treatment (correlation coefficient = 0.63 and 0.64, p = 0.01 and 0.002, respectively) but not with the PASI. Capillary and papillary diameters after treatment and percentage reduction of the PASI during treatment seemed to be better predictors for the clinical course of relapse than the PASI after treatment. These findings make the subclinical changes of psoriatic skin vessels and dermal papillae a legitimate target for treatment. Further investigations of a large group of patients are needed to evaluate the potential of RCM findings as successor of the PASI in the monitoring of psoriasis.

Palmoplantar erythrodysesthesia-like skin symptoms in patients under various chemotherapeutics: preventive and therapeutic options.

BACKGROUND/AIMS: The palmoplantar erythrodysaesthesia (PPE) is an inflammatory cutaneous side effect in patients under chemotherapy with pegylated liposomal doxorubicin (PLD), with indications that also other chemotherapeutics induce similar side effects. Recently, it has been demonstrated that PLD escapes with the sweat onto the skin inducing radical-forming processes that damage the skin. The topical application of antioxidants with a high radical protection factor has proven to be a very efficient prevention strategy for PLD-treated patients. METHODS: 68 patients, who had been treated with 12 different chemotherapeutics and experienced side effects similar to PPE, were treated with a meanwhile commercially available ointment. RESULTS: At the beginning of the therapy, 46 patients suffered from a PPE of severity grade III, while in 22 patients a PPE of severity grade II was diagnosed. The application of the ointment resulted in a significant improvement of the clinical symptoms and the skin status in all these patients; their chemotherapies could be continued. CONCLUSION: The obtained results suggest that radical-forming processes play an essential role in a great number of chemotherapeutics which induce dermal side effects. The topical application of the antioxidant-containing ointment proved to be a good therapeutic option which needs further evaluation.

Influence of massage and occlusion on the ex vivo skin penetration of rigid liposomes and invasomes.

Liposomes are frequently described as drug delivery systems for dermal and transdermal applications. Recently, it has been shown that particulate substances penetrate effectively into hair follicles and that the follicular penetration depth can be increased by massaging the skin, which simulates the in vivo movement of hairs in the hair follicles. In the present study, massage was applied to skin mounted to Franz diffusion cells. By means of confocal laser scanning microscopy, the influence of massage and occlusion on the follicular penetration depths of rigid and flexible liposomes loaded with a hydrophilic and lipophilic dye was investigated. The application of massage increased follicular penetration significantly. Occlusion resulted in an increased follicular penetration depth only for rigid liposomes, whereas invasomes did not penetrate more effectively if occlusion was applied. The results confirm that massage is an important tool for increasing follicular penetration in ex vivo studies using Franz diffusion cells. Occlusion may reduce the efficacy of follicular penetration depending on the specific liposomal preparation. Rigidity in particular appears to be a relevant parameter.

Efficient prevention strategy against the development of a palmar-plantar erythrodysesthesia during chemotherapy.

BACKGROUND: Pegylated liposomal doxorubicin (PLD) is a highly efficient chemotherapeutic; however, it induces dermal side effects such as palmar-plantar erythrodysesthesia (PPE) in up to 80% of cases, probably by being emitted with the sweat onto the skin surface. AIM: The aim of the present study was to examine whether a topically applied ointment containing antioxidants with a high radical protection factor is able to prevent the formation of PPE. METHODS: Twenty patients suffering from ovarian carcinoma and treated with PLD were observed. RESULTS: 60% of the patients tolerated the regular application of the cream and developed no PPE. The remaining 40% interrupted the application. Six of them developed PPE and resumed ointment application thereafter. In these cases the PPE disappeared or was strongly reduced. CONCLUSION: The results of the observation clearly demonstrate that topical application of the ointment is an efficient strategy against the development of PPE during chemotherapy with PLD.

Comparison of the skin penetration of Garcinia mangostana extract in particulate and non-particulate form.

The aim of the present study was to solve the water insolubility limitation of the medically and cosmetically interesting substance Garcinia mangostana Linn (GML) extract by encapsulation, and to evaluate and investigate the penetration efficacy of free and encapsulated GML in two different vehicles (water and cream) in porcine ear skin. The follicular penetration depth was determined in 50 hair follicles for each of the four formulations by means of fluorescence microscopy. Tape stripping was used to compare the distribution properties of GML with all formulations on the stratum corneum. The results showed that encapsulated and free GML in the cream base penetrated deeper into hair follicles than if applied in an aqueous base. In addition, encapsulated GML could be distributed more homogeneously on the stratum corneum than the free GML. In conclusion, it was found that encapsulated GML in a cream base had the most effective penetration level in porcine ear skin.

Drug delivery into the skin by degradable particles.

Recently, it was demonstrated that particles could be utilized as carrier systems for drugs into the hair follicles. In the present study, a two-component drug delivery system is presented consisting of degradable particles loaded with fluorescein isothiocyanate and a separate protease formulation for degradation. The particles were applied alone, 30 min previous to the protease application and simultaneously with the protease onto porcine skin. Subsequently, biopsies were removed, and the penetration depths of the particles were analyzed using laser scanning microscopy. The obtained results demonstrate that the particles alone achieved a penetration depth of around 900 µm. Similar results were obtained for the successive application of particles and protease, whereas a release of the fluorescent dye was only observed in the upper 250 µm corresponding to the penetration depth of the protease. In the case of the simultaneous application, the particles were partly dissolved before application, leading to a reduced particle size and diminished penetration depth. The results revealed that degradable particles are a promising tool for drug delivery into the skin.

One-year study on the variation of carotenoid antioxidant substances in living human skin: influence of dietary supplementation and stress factors.

Variation in the level of the carotenoid antioxidant substances beta-carotene and lycopene in the human skin of ten healthy volunteers was measured with resonance Raman spectroscopy in an in vivo experiment over the course of 12 months. Information on the lifestyle of the volunteers concerning dietary supplementation and stress factors was obtained daily by the completion of questionnaires. The results showed individual variations in the levels of carotenoid antioxidant substances in the skin of the volunteers, which strongly correlated to specific lifestyles, such as the intake of dietary supplementations rich in carotenoids, and the influence of stress factors. A carotenoid-rich nutrition, based on large amounts of fruit and vegetables, increased the measured carotenoid levels of skin, while stress factors such as fatigue, illness, smoking, and alcohol consumption gave rise to a decrease in carotenoid levels of the skin. These decreases occurred relatively quickly over the course of one day, while the subsequent increases lasted for up to 3 days. During the summer and autumn months, an increase in the level of carotenoids in the skin was measured for all volunteers. The average "seasonal increase" of the carotenoid content in the skin was determined to be 1.26-fold.

Differential stripping demonstrates a significant reduction of the hair follicle reservoir in vitro compared to in vivo.

Penetration studies are commonly performed on in vitro models, presumably due to a lack of non-invasive in vivo methods. To date, it is not clear whether in vitro models are suitable to reflect the in vivo conditions for percutaneous penetration. Apart from inter and intraspecies skin differences, the excision of a skin sample may influence the penetration rate inter alia as a result of the contraction of the elastic fibres in the skin during excision. Therefore, the aim of the present study was to investigate the follicular reservoir of the hair follicles of human skin in vivo and in vitro utilizing the method of differential stripping. The results obtained revealed a significantly reduced follicular reservoir in vitro, which was only 9.5+/-10.6% of the in vivo reservoir. These results are important for the interpretation of earlier and future penetration investigations. It can thus be assumed that excised skin models are suitable for penetration studies only to a limited extent, as follicular penetration is greatly diminished due to the contraction of the elastic fibres of the skin.