Cationic membrane-active peptides - anticancer and antifungal activity as well as penetration into human skin.

Cationic antimicrobial peptides are ancient natural broad-spectrum antibiotics, and several compounds also exhibit anticancer activity. However, most applications pertain to bacterial infections, and treatment for skin cancer is less frequently considered. The cytotoxicity of melittin, cecropin A, protegrin-1 and histatin 5 against squamous skin cancer cell lines and normal human keratinocytes was evaluated and compared to established drugs. The results show that melittin clearly outperforms 5-fluorouracil regarding antitumor activity. Importantly, combined melittin and 5-fluorouracil enhanced cytotoxic effects on cancer cells and reduced toxicity on normal keratinocytes. Additionally, minimum inhibitory concentrations indicate that melittin also shows superior activity against clinical and laboratory strains of Candida albicans compared to amphotericin B. To evaluate its potential for topical applications, human skin penetration of melittin was investigated ex vivo and compared to two non-toxic cell-penetrating peptides (CPPs), low molecular weight protamine (LMWP) and penetratin. The stratum corneum prevents penetration into viable epidermis over 6 h; however, the peptides gain access to the viable skin after 24 h. Inhibition of digestive enzymes during skin penetration significantly enhances the availability of intact peptide. In conclusion, melittin may represent an innovative agent for non-melanoma skin cancer and infectious skin diseases. In order to develop a drug candidate, skin absorption and proteolytic digestion by skin enzymes need to be addressed.

Esterase activity in excised and reconstructed human skin--biotransformation of prednicarbate and the model dye fluorescein diacetate.

Reconstructed human epidermis (RHE) is used in non-animal testing for hazard analysis and reconstructed human skin (RHS) gains growing interest in preclinical drug development. RHE and RHS have been characterised regarding their barrier function, but knowledge about biotransformation capacity in these constructs and in human skin remains rather poor. However, metabolising enzymes can be highly relevant for the efficacy of topical dermatics as well as genotoxicity and sensitisation. We have compared the esteratic cleavage of the prednisolone diester prednicarbate and the enzyme kinetic parameters (Vmax and S0.5) of the model substrate fluorescein diacetate (FDA) in commercially available RHS and RHE with excised human skin and monolayer cultures of normal and immortalised human keratinocytes and of fibroblasts. Formation of the main metabolite prednisolone and of fluorescein ranked as: RHS~RHE>excised human skin and keratinocytes>fibroblasts, respectively. Because of the aromatic probe, however, Vmax of FDA cleavage did not show a linear relationship with prednicarbate metabolism. In conclusion, RHE and RHS may be useful to quantitatively address esterase activity of human skin in drug development and hazard analysis, although an increased activity compared to native human skin has to be taken into account.

A peptide derived from the highly conserved protein GAPDH is involved in tissue protection by different antifungal strategies and epithelial immunomodulation.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has an important role not only in glycolysis but also in nonmetabolic processes, including transcription activation and apoptosis. We report the isolation of a human GAPDH (hGAPDH) (2-32) fragment peptide from human placental tissue exhibiting antimicrobial activity. The peptide was internalized by cells of the pathogenic yeast Candida albicans and initiated a rapid apoptotic mechanism, leading to killing of the fungus. Killing was dose-dependent, with 10 µg ml (3.1 µM) and 100 µg ml hGAPDH (2-32) depolarizing 45% and 90% of the fungal cells in a population, respectively. Experimental C. albicans infection induced epithelial hGAPDH (2-32) expression. Addition of the peptide significantly reduced the tissue damage as compared with untreated experimental infection. Secreted aspartic proteinase (Sap) activity of C. albicans was inhibited by the fragment at higher concentrations, with a median effective dose of 160 mg l(-1) (50 µM) for Sap1p and 200 mg l(-1) (63 µM) for Sap2p, whereas Sap3 was not inhibited at all. Interestingly, hGAPDH (2-32) induced significant epithelial IL-8 and GM-CSF secretion and stimulated Toll-like receptor 4 expression at low concentrations independently of the presence of C. albicans, without any toxic mucosal effects. In the future, the combination of different antifungal strategies, e.g., a conventional fungicidal with immunomodulatory effects and the inhibition of fungal virulence factors, might be a promising treatment option.

Glycosylation of Candida albicans cell wall proteins is critical for induction of innate immune responses and apoptosis of epithelial cells.

C. albicans is one of the most common fungal pathogen of humans, causing local and superficial mucosal infections in immunocompromised individuals. Given that the key structure mediating host-C. albicans interactions is the fungal cell wall, we aimed to identify features of the cell wall inducing epithelial responses and be associated with fungal pathogenesis. We demonstrate here the importance of cell wall protein glycosylation in epithelial immune activation with a predominant role for the highly branched N-glycosylation residues. Moreover, these glycan moieties induce growth arrest and apoptosis of epithelial cells. Using an in vitro model of oral candidosis we demonstrate, that apoptosis induction by C. albicans wild-type occurs in early stage of infection and strongly depends on intact cell wall protein glycosylation. These novel findings demonstrate that glycosylation of the C. albicans cell wall proteins appears essential for modulation of epithelial immunity and apoptosis induction, both of which may promote fungal pathogenesis in vivo.

Impact of age and body site on adult female skin surface pH.

BACKGROUND: pH is known as an important parameter in epidermal barrier function and homeostasis. AIM: The impact of age and body site on skin surface pH (pH(SS)) of women was evaluated in vivo. METHODS: Time domain dual lifetime referencing with luminescent sensor foils was used for pH(SS) measurements. pH(SS) was measured on the forehead, the temple, and the volar forearm of adult females (n = 97, 52.87 ± 18.58 years, 20-97 years). Every single measurement contained 2,500 pH values due to the luminescence imaging technique used. RESULTS: pH(SS) slightly increases with age on all three investigated body sites. There are no significant differences in pH(SS) between the three investigated body sites. CONCLUSION: Adult pH(SS) on the forehead, the temple and the volar forearm increases slightly with age. This knowledge is crucial for adapting medical skin care products.

Medical devices in dermatology: topical semi-solid formulations for the treatment of skin diseases.

In recent years, topically applied semi-solid formulations certified as medicals devices and not as topical drugs are increasingly used for the treatment of skin diseases. Medical devices primarily unfold their therapeutic effect by physical means, not by pharmacological, immunological or metabolic means. Intensified placing of medical devices on the dermatological market may at least partly be explained by a less complex marketing authorization process compared to topical drugs. If the requirements are fulfilled to certify a product as a medical device the opportunity will be offered to quickly introduce innovations onto the market and propagate them. A variety of evidence-based medical devices for several dermatological indications are presented here.

The Munich outbreak of cutaneous cowpox infection: transmission by infected pet rats.

Cowpox virus infection of humans is an uncommon, potentially fatal, skin disease. It is largely confined to Europe, but is not found in Eire, or in the USA, Australasia, or the Middle or Far East. Patients having contact with infected cows, cats, or small rodents sporadically contract the disease from these animals. We report here clinical aspects of 8 patients from the Munich area who had purchased infected pet rats from a local supplier. Pet rats are a novel potential source of local outbreaks. The morphologically distinctive skin lesions are mostly restricted to the patients' necks, reflecting the infected animals' contact pattern. Individual lesions vaguely resemble orf or Milker's nodule, but show marked surrounding erythema, firm induration and local adenopathy. Older lesions develop eschar, leaving slow-healing, deep ulcerative defects after eschar separation. Severe flu-like illness may be present in the acute phase. Smallpox-vaccinated patients tend to develop less severe reactions and heal more quickly. The differential diagnosis may include other localized orthopoxvirus infections, herpes simplex, bacterial infection, anthrax, foreign body granuloma, and primary tuberculosis. Dermatologists should be aware of the diagnostic and therapeutic algorithms for handling this disease.

Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment.

BACKGROUND: Due to its strong water-binding potential, hyaluronic acid (HA) is a well-known active ingredient for cosmetic applications. Native HA is proposed to help the skin to retain and maintain elasticity, turgor and moisture. OBJECTIVE: To observe the efficacy of topical application of 0.1% hyaluronan formulations of different molecular weights (MW) (50, 130, 300, 800 and 2000 kDa, respectively) in the periocular area as anti-wrinkle treatment. MATERIAL AND METHODS: Seventy-six female subjects between 30 and 60 years of age with clinical signs of periocular wrinkles applied one of the formulations twice-daily to the area of interest in a randomized fashion for 60 days. Around the other eye, a vehicle control cream was applied. Measurements of skin hydration and skin elasticity were performed before treatment, 30 and 60 days thereafter. At similar time points negative replicas were taken and evaluated by semi-automated morphometry. RESULTS: All HA-based creams utilized in this study demonstrated a significant improvement in skin hydration and overall elasticity values (R2) when compared to placebo. Measurements of wrinkle depth using mean roughness (Ra) and maximum roughness (Rz) values revealed significant improvement in the 130 and the 50 kDa HA group after 60 days of treatment compared to placebo-treated area. CONCLUSION: Topical application of all 0.1% HA formulations used in this study led to significant improvement in skin hydration and elasticity. Application of low-molecular-weight (LMW) HA was associated with significant reduction of wrinkle depth, which may be due to better penetration abilities of LMW HA.

Hallmarks of atopic skin mimicked in vitro by means of a skin disease model based on FLG knock-down.

Loss-of-function mutations in the filaggrin gene (FLG) are a strong predisposing factor for atopic dermatitis, although their relevance to the disease pathomechanism needs further elucidation. The generation of an in vitro model of atopic skin would not only permit further evaluation of the underlying pathogenetic mechanisms and the testing of new treatment options, but would also allow toxicological studies to be performed in a simple, rapid and inexpensive manner. In this study, we have knocked down FLG expression in human keratinocytes and created three-dimensional skin models, which we used to investigate the impact of FLG on epidermal maturation and on skin absorption and its response to irritation. Histopathological evaluation of the skin models showed impaired epidermal differentiation in the FLG knock-down model. In addition, skin irritation induced by an application of sodium dodecyl sulphate resulted in significantly higher lactate dehydrogenase leakage, and interleukin (IL)-6 and IL-8 levels, than in the control model. To assess the effect of filaggrin deficiency on skin absorption of topically applied agents, we quantified the percutaneous absorption of lipophilic and hydrophilic model drugs, finding clinical relevance only for lipophilic drugs. This study clearly demonstrates that important clinical characteristics of atopic skin can be mimicked by using in vitro skin models. The FLG knock-down construct is the first step toward an in vitro model that allows clinical and toxicological studies of atopic-like skin.

Chitin modulates innate immune responses of keratinocytes.

BACKGROUND: Chitin, after cellulose the second most abundant polysaccharide in nature, is an essential component of exoskeletons of crabs, shrimps and insects and protects these organisms from harsh conditions in their environment. Unexpectedly, chitin has been found to activate innate immune cells and to elicit murine airway inflammation. The skin represents the outer barrier of the human host defense and is in frequent contact with chitin-bearing organisms, such as house-dust mites or flies. The effects of chitin on keratinocytes, however, are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: We hypothesized that chitin stimulates keratinocytes and thereby modulates the innate immune response of the skin. Here we show that chitin is bioactive on primary and immortalized keratinocytes by triggering production of pro-inflammatory cytokines and chemokines. Chitin stimulation further induced the expression of the Toll-like receptor (TLR) TLR4 on keratinocytes at mRNA and protein level. Chitin-induced effects were mainly abrogated when TLR2 was blocked, suggesting that TLR2 senses chitin on keratinocytes. CONCLUSIONS/SIGNIFICANCE: We speculate that chitin-bearing organisms modulate the innate immune response towards pathogens by upregulating secretion of cytokines and chemokines and expression of MyD88-associated TLRs, two major components of innate immunity. The clinical relevance of this mechanism remains to be defined.

Direct detection of five common dermatophyte species in clinical samples using a rapid and sensitive 24-h PCR-ELISA technique open to protocol transfer.

Identification of dermatophytes is usually based on morphological characteristics determined by time-consuming microscopic and cultural examinations. An effective PCR-ELISA method has been developed for rapid detection of dermatophyte species directly from clinical specimens within 24 h. Isolated genomic DNA of skin scrapings and nail samples from patients with suspected dermatophyte infections is amplified with species-specific digoxigenin-labelled primers targeting the topoisomerase II gene. The subsequent ELISA procedure with biotin-labelled probes allows a sensitive and specific identification of the five common dermatophytes -Trichophyton rubrum, T. interdigitale, T. violaceum, Microsporum canis and Epidermophyton floccosum. PCR-ELISA, based on the new polyphasic species concept, was assessed using 204 microscopy-positive samples in two university mycological laboratories in Munich and Tübingen, and 316 consecutive specimens - regardless of mycological findings - in a dermatological practice laboratory in Neu-Ulm. One of the five dermatophytes was confirmed by PCR-ELISA in 163 of 204 (79.9%) of the clinical samples from the university hospitals found positive using microscopy. Culture was positive for dermatophytes in 59.8% of the same cases. A significant difference between these two methods could be demonstrated using the McNemar test (P < 0.005). Analysis of specimens from Neu-Ulm confirmed the results in a dermatological practice laboratory as 25.0% of the specimens had positive PCR results, whereas only 7.3% were positive according to culture. Direct DNA isolation from clinical specimens and the PCR-ELISA method employed in this study provide a rapid, reproducible and sensitive tool for detection and discrimination of five major dermatophytes at species level, independent of morphological and biochemical characteristics.

Which plant for which skin disease? Part 2: Dermatophytes, chronic venous insufficiency, photoprotection, actinic keratoses, vitiligo, hair loss, cosmetic indications.

This paper continues our review of scientifically evaluated plant extracts in dermatology. After plants effective against dermatophytes, botanicals with anti-edema effects in chronic venous insufficiency are discussed. There is good evidence from randomized clinical studies that plant extracts from grape vine leaves (Vitis vinifera), horse chestnut (Aesculus hippocastanum), sea pine (Pinus maritima) and butcher's broom (Ruscus aculeatus) can reduce edema in chronic venous insufficiency. Plant extracts from witch hazel (Hamamelis virginiana), green tea (Camellia sinensis), the fern Polypodium leucotomos and others contain antioxidant polyphenolic compounds that may protect the skin from sunburn and photoaging when administered topically or systemically. Extracts from the garden spurge (Euphorbia peplus) and from birch bark (Betula alba) have been shown to be effective in the treatment of actinic keratoses in phase II studies. Some plant extracts have also been investigated in the treatment of vitiligo, various forms of hair loss and pigmentation disorders, and in aesthetic dermatology.

Monophasic, cohesive-polydensified-matrix crosslinking-technology-based hyaluronic acid filler for the treatment of facial lipoatrophy in HIV-infected patients.

Human immunodeficiency virus (HIV)-associated facial lipoatrophy (FLA) represents a common and highly stigmatizing side effect of retroviral therapy. By causing loss of subcutaneous adipose tissue mainly in the cheek, temple and periocular area, FLA can significantly affect the patient's quality of life, both physically and psychologically. A limited quantity of data has been published on various filling substances for the management of FLA. Here, the authors present two patients with HIV-associated FLA successfully treated with a novel HA filler over a period of 24 months.

Antitumor effects of guanosine-analog phosphonates identified by molecular modelling.

Aiming to address new drug targets, molecular modelling is gaining increasing importance although the prediction capability of the in silico method is still under debate. For an improved treatment of actinic keratosis and squamous cell carcinoma, inhibitors of human DNA polymerase alpha (pol alpha) are developed by docking nucleoside phosphonate diphosphates into the active site of pol alpha. The most promising prodrugs OxBu and OxHex were then prepared by total synthesis and tested in the squamous cancer cell line SCC25. OxBu and OxHex proved cytotoxic and antiproliferative in the nanomolar concentration range and thus exceeded activity of aphidicolin, the relevant model compound, and 5-fluorouracil, the current standard for the therapy of actinic keratosis. Interestingly, the cytotoxicity in normal human keratinocytes with OxHex was clearly less pronounced and even not detectable with OxBu. Moreover, cytotoxicity of OxBu in particular with the colorectal carcinoma cell line HT29 even surmounted cytotoxicity in SCC25, and other tumor cell lines were influenced, too, by both agents. Taken together, OxBu and OxHex may offer a new approach to cancer therapy, given the agents are sufficiently well tolerated in vivo which is to be suspected beside their chemical structure.

Human polymerase alpha inhibitors for skin tumors. Part 2. Modeling, synthesis and influence on normal and transformed keratinocytes of new thymidine and purine derivatives.

Recently, the three-dimensional structure of the active site of human DNA polymerase alpha (pol alpha) was proposed based on the application of molecular modeling methods and molecular dynamic simulations. The modeled structure of the enzyme was used for docking selective inhibitors (nucleotide analogs and the non-nucleoside inhibitor aphidicolin) in its active site in order to design new drugs for actinic keratosis and squamous cell carcinoma (SCC). The resulting complexes explained the geometrical and physicochemical interactions of the inhibitors with the amino acid residues involved in binding to the catalytic site, and offered insight into the experimentally derived binding data. The proposed structures were synthesized and tested in vitro for their influence on human keratinocytes and relevant tumor cell lines. Effects were compared to aphidicolin which inhibits pol alpha in a non-competitive manner, as well as to diclofenac and 5-fluorouracil, both approved for therapy of actinic keratosis. Here we describe three new nucleoside analogs inhibiting keratinocyte proliferation by inhibiting DNA synthesis and inducing apoptosis and necrosis. Thus, the combination of modeling studies and in vitro tests should allow the derivation of new drug candidates for the therapy of skin tumors, given that the agents are not relevant substrates of nucleotide transporters expressed by skin cancer cells. Kinases for nucleoside activation were detected, too, corresponding with the observed effects of nucleoside analogs.

Bilateral areolar and periareolar pityriasis versicolor.

An adolescent boy presented with isolated, symmetrical, bilateral areolar and periareolar pityriasis versicolor. This extremely rare condition should be considered in the differential diagnosis of light brown patches on the areolae.

Safety and efficacy of sertaconazole nitrate cream 2% in the treatment of tinea pedis interdigitalis: a subgroup analysis.

Sertaconazole nitrate is a broad-spectrum antifungal agent indicated in the United States for the treatment of tinea pedis interdigitalis. The objective of this subgroup analysis was to evaluate the safety and efficacy of sertaconazole nitrate cream 2%, specifically in participants with tinea pedis interdigitalis (ie, fungal skin disease of the toe web) of dermatophyte origin. A total of 92 participants were included in this analysis. The primary end points were eradication of the pathogen (confirmed by fungal culture results) and reduction in total clinical score (TCS) of at least 2 points. Secondary end points included reducing signs and symptoms and reporting adverse events (AEs). After 4 weeks of treatment, 88.8% (79/89) of evaluable participants achieved success on the primary end points. Most participants also demonstrated substantial improvement in signs and symptoms after 4 weeks of treatment: 63.7% (58/91) were free of erythema, 33.0% (30/91) were free of desquamation, and 91.2% (83/91) were free of itch. The rate of reported AEs was low (8.7% [8/92]), and none were considered serious. These findings indicate that sertaconazole nitrate cream 2% is highly safe and effective in the treatment of tinea pedis interdigitalis.

Carriers in the topical treatment of skin disease.

Topical drug application is less prone to severe systemic side-effects than systemic application. Starting with the liposomes, various types of nanosized and microsized drug carriers have been developed to increase the notoriously low penetration of active agents into the skin, which limits not only the topical therapy of skin disease but also transdermal therapy. Today, liposome- and microsponge-based preparations are approved for dermatomycosis, acne and actinic keratosis. Under investigation are drug carriers such as lipid nanoparticles, polymeric particles, dendrimers, and dendritic-core multi-shell nanotransporters. According to the rapidly increasing research in this field, both in academia and industry, a breakthrough appears likely, once stability problems (nanoparticles) and safety concerns (dendrimers) are overcome. Technical approaches and results of in vitro, ex vivo and in vivo testing are described, taking into account pharmacokinetic, efficacy and safety aspects.