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The Study about Relief Effect of Essential Oil on Seborrheic Dermatitis with Co-culture System
Abstract
Seborrheic dermatitis (SD) is the skin disease occurred because of Malassezia yeast which grows on the skin and scalp, and this yeast lives on sebum lipid, and their metabolite, free lipid acids are thought to be the main irritant on skin. To find out effective cosmeceutical ingredients to treat SD symptoms, we established novel cell-based in vitro model mimicking SD symptoms. This in vitro model adopted the co-culture system with primary sebocyte & HaCaT keratinocyte. We used M. globosa yeast extract, arachidonic acid, linoleic acid and dihydrotestosterone as SD inducers. In the co-culture system with optimized concentrations for SD-inducing cocktail, the production of IL-8 and sebum lipids increased up to 2-fold, and then we screened with commercial essential oils by monitoring IL-8 as a key inflammatory biomarker. Then we found that Cinnamomum zeylanicum oil, Mentha arvensis oil effectively down-regulated IL-, IL-6, IL-8 cytokines which over-produced by SD-inducing cocktail. Additionally, two essential oils also showed inhibitory effect on sebum lipid synthesis from primary sebocyte and growth inhibitory effect to M. globosa yeast (MICs were lower than 0.0625 %). Our recent results suggest that Cinnamomum zeylanicum oil and Mentha arvensis oil could be effective natural herbal remedies to relieve or protect scalp seborrheic dermatitis.
... 58 Regardless of the causes, excessive sebum in the scalp produces the ideal environment for the development and proliferation of pathogenic microorganisms, such as Malassezia spp., whose action may result in itching, dandruff, visible inflammation, reduced peripheral blood circulation, and hair loss. 16,59 Currently, there are several types of treatments related to hair and scalp disorders, mainly with the use of synthetic products like minoxidil, as in the hair loss treatment. 59 According to Farboud et al., 58 no product applied locally can cure acute seborrhea, and only relatively toxic synthetic compounds with serious adverse effects can reduce the secretion of sebaceous glands, such as anti-inflammatory agents as zinc pyrithione, ketoconazole, and terbinafine. ...
... 16,59 Currently, there are several types of treatments related to hair and scalp disorders, mainly with the use of synthetic products like minoxidil, as in the hair loss treatment. 59 According to Farboud et al., 58 no product applied locally can cure acute seborrhea, and only relatively toxic synthetic compounds with serious adverse effects can reduce the secretion of sebaceous glands, such as anti-inflammatory agents as zinc pyrithione, ketoconazole, and terbinafine. However, it is reported that some disorders may be treated with the use of specific natural ingredients incorporated or not into cosmetic formulations, due to reduced adverse effects, fewer hypersensitivity reactions, and, in some cases, higher effects than the synthetic ones. ...
... However, it is reported that some disorders may be treated with the use of specific natural ingredients incorporated or not into cosmetic formulations, due to reduced adverse effects, fewer hypersensitivity reactions, and, in some cases, higher effects than the synthetic ones. 13,59 The field of cosmetic dermatology is growing with the associa- The EO active ingredients can penetrate in the scalp quickly, nourish the deep hair follicles, supplement the nutrition, stimulate the hair follicle growth, moisturize the hair roots, strengthen the hair, and even effectively remove unwanted metabolites that block the pores. 63 Seborrhea is a pathology that can cause oiliness on both scalp and hair. ...
Background
Essential oils have great interest among the increasing demand for herbal cosmetics in the market. They are natural sources of biologically active ingredients due to the wide application of such compounds as well as their particular chemical composition. Several researches have evaluated the effectiveness of these bioactive ingredients for use in cosmeceuticals, mainly in both hair scalp and shaft hair damage repair. Thus, the amounts and their associations define the properties of these compositions with interest for hair cosmetic use, such as antioxidant, inflammatory, and antimicrobial activities. Because they are complex compounds, their actions on the skin, hair scalp, and shaft are not yet fully understood.
Aims
The purpose of this review is to highlight the relevant researches and findings on essential oils in hair care.
Methods
In order to achieve this objective, the present work comprises an updated bibliographic review related to essential oils used in hair care.
Results
It was possible to observe that cosmeceuticals containing essential oils applied to the scalp are preferably for topical activity. Also, it was noticed that there are few reports regarding their use in hair shaft. However, it was found that some oils are used to intensify the brightness and fix the hair color.
Conclusions
This work demonstrated that the use of essential oils in both cosmetic products (industrial application) and those associated with oils carriers (as individual protocols) may lead to satisfactory results in the treatment of some scalp dysfunctions.
... Additionally, it also showed inhibitory effect on sebum lipid synthesis from primary sebocyte and growth inhibitory effect to Malassezia globosa yeast. As a result, Cinnamomum zeylanicum essential oil suggested as a natural herbal remedy to relieve or protect scalp SD (Kim, Kim, Lee, Jeon, & Park, 2012). ...
In this study, it was aimed to develop a topically applicable nanoemulsion (NE) that is expected to have an ameliorating effect in seborrheic dermatitis (SD). The main purpose of the formulation is to eliminate the disease factor, to repair the damage caused by the disease on the skin and to smooth the skin appearance by moisturization. For this reason, in vitro antimicrobial effect and in vivo effectiveness of the formulation were tested. For this aim; essential oils from tea tree, sage, cinnamon, oregano; extracts from Aloe vera, colloidal oatmeal, liquorice; vegetable oils from grape seed and sesame, and honey were used in a NE formulation. The NEs were prepared by ultrasonication method. Preliminary stability tests were applied to all formulations and then, pH, conductivity, viscosity, average droplet size, polydispersity index (PDI), and zeta potential measurements were taken on the selected NEs for 3 months. Finally, the antimicrobial effect and in vivo effectiveness of the optimum NE were tested. The average droplet size, PDI, and zeta potential value of the optimum formulation (F6P2) were 108.40 ± 0.90 nm, 0.195 ± 0.07, and-21.40 ± 1.45 mV, respectively. As a result, the moisture content of the skin increased significantly (p < 0.001), the sebum and redness values significantly decreased (p = 0.008 and 0.001, respectively) and there was no significant change in the pH of the volunteers' skin. Accordingly, it can be concluded that the optimum NE formulation developed in this study may be beneficial as a supplement for patients with SD. ÖZ Bu çalışmada seboreik dermatitte (SD) iyileştirici etkisi olması beklenen topikal olarak uygulanabilir bir nanoemülsiyon (NE) geliştirilmesi amaçlanmıştır. Formülasyonun temel amacı hastalık faktörünü ortadan kaldırmak, hastalığın ciltte verdiği hasarı onarmak ve nemlendirerek cilt görünümünü pürüzsüz hale getirmektir. Bu nedenle formülasyonun in vitro antimikrobiyal etkisi ve in vivo etkinliği test edilmiştir. Bu amaç için NE formülasyonunda; çay ağacı, adaçayı, tarçın, kekik esansiyel yağları; Aloe vera, kolloidal yulaf ezmesi, meyan kökü ekstreleri; üzüm çekirdeği ve susamdan elde edilen bitkisel yağlar ve bal kullanılmıştır. NE'ler ultrasonikasyon yöntemiyle hazırlanmıştır. Tüm formülasyonlara ön stabilite testleri uygulanmış ve ardından seçilen NE'ler üzerinde 3 ay boyunca pH, iletkenlik, viskozite, ortalama damlacık boyutu, polidispersite indeksi (PDI) ve zeta potansiyel ölçümleri alınmıştır. Son olarak, optimum NE'nin antimikrobiyal etkisi ve in vivo etkinliği test edilmiştir. Optimum formülasyonun (F6P2) ortalama damlacık boyutu, PDI ve zeta potansiyel değeri sırasıyla 108,40 ± 0,90 nm, 0,195 ± 0,07 ve-21,40 ± 1,45 mV olarak bulunmuştur. Sonuç olarak, cildin nem içeriği önemli ölçüde artmış (p < 0,001), sebum ve kızarıklık değerleri önemli ölçüde azalmış (sırasıyla p = 0,008 ve 0,001) ve gönüllülerin cildinin pH'ında önemli bir değişiklik meydana gelmemiştir. Buna göre, bu çalışmada geliştirilen optimum NE formülasyonunun SD'li hastalar için ek olarak faydalı olabileceği sonucuna varılabilir.
This study surveyed 150 men aged 30 to 50, a demographic which seborrheic dermatitis is common. The time of day one shampoos and recurrent fatigue were found to have a statistically significant impact on symptoms contributing to the main causes of seborrhea, including itchiness, excessive oil, acne, and redness on the scalp (p
The present study was conducted to isolate the most important bioactive compound from Cinnamomum zeylanicum L. (Lauraceae) bark oil. The plant essential oil was extracted via steam distillation. Cinnamaldehyde was separated using a separating funnel and identified according to Tollen’s test followed by detection on TLC plates in comparison with standard cinnamaldehyde that served as positive control. Moreover, FTIR spectrometry and HPLC analysis were used to confirm the purity and identity of cinnamaldehyde. The isolated material was investigated for its antibacterial activity against six selected pathogenic bacteria. The Gram-positive bacteria were Staphylococcus aureus and Bacillus cereus; Gram-negative bacteria included Escherichia coli, Proteus mirabilis, Klebsiella pneumonia, and Pseudomonas aeruginosa. Cinnamaldehyde at different concentrations (1:1, 1:5, 1:10 and 1:20) was active against all tested bacteria and the highest inhibitory effect was observed against B. cereus (zone of inhibition: 25.3 mm) using the disk diffusion method. The minimal inhibitory concentration (MIC) of cinnamaldehyde was determined using a broth microdilution method in 96-well microtiter plates. MIC values ranged from 31.2 to 125.0 μg/mL. The most promising result was observed against B. cereus, while S. aureus, E. coli, and K. pneumonia ranked next (MIC: 62.5 μg/mL) followed by P. mirabilis and P. aeruginosa with a MIC of 125.0 μg/mL.
p63 is a p53 family protein required for morphogenesis and postnatal regeneration of epithelial tissues. Here we demonstrate that ΔNp63α, a p63 isoform lacking the N-terminal transactivation domain, induces epithelial-mesenchymal transition (EMT) in primary human keratinocytes in a TGF-β-dependent manner. Rapidly proliferating normal human epidermal keratinocytes (NHEK) were infected with retroviral vector expressing ΔNp63α or empty vector and serially subcultured until replicative senescence. No phenotypic changes were observed until the culture reached senescence. Then the ΔNp63α-transduced cells underwent morphological changes resembling mesenchymal cells and acquired the EMT phenotype. Treatment with exogenous TGF-β accelerated EMT in presenescent ΔNp63α-transduced cells, whereas the inhibition of TGF-β signaling reversed the EMT phenotype. TGF-β treatment alone led to growth arrest in control NHEK with no evidence of EMT, indicating that ΔNp63α altered the cellular response to TGF-β treatment. ΔNp63α-transduced cells acquiring EMT gained the ability to be differentiated to osteo-/odontogenic and adipogenic pathways, resembling mesenchymal stem cells. Furthermore, these cells expressed enhanced levels of Nanog and Lin28, which are transcription factors associated with pluripotency. These data indicate that EMT required ΔNp63α transduction and intact TGF-β signaling in NHEK.
Seborrhoeic dermatitis affects at least 1-3% of the population. Malassezia (Pityrosporum) ovale is thought to be the causative organism, and causes inflammation involving T cells and complement. Seborrhoeic dermatitis tends to relapse after treatment. METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of topical treatments for seborrhoeic dermatitis of the scalp in adults? What are the effects of topical treatments for seborrhoeic dermatitis of the face and body in adults? We searched: Medline, Embase, The Cochrane Library and other important databases up to February 2006 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found nine systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: bifonazole, emollients, ketoconazole, lithium succinate, selenium sulphide, tar shampoo, terbinafine, and topical steroids (betamethasone valerate, clobetasol propionate, clobetasone butyrate, hydrocortisone, mometasone furate).
Malassezia spp. are commensal, cutaneous fungi that are implicated in seborrhoeic dermatitis. We hypothesize that the lipid-rich capsule of Malassezia spp. masks the organism from host detection, and depletion of this layer elicits an inflammatory response. To test this, preparations of capsulated or acapsular [10% (v/v) Triton X-100 treated], viable and nonviable, exponential or stationary phase Malassezia furfur, Malassezia globosa, Malassezia obtusa, Malassezia restricta, Malassezia slooffiae and Malassezia sympodialis, were incubated with normal human keratinocytes. Proinflammatory (IL-6, IL-8, IL-1alpha and tumour necrosis factor-alpha) and anti-inflammatory cytokine (IL-10) release and intracellular IL-10 concentrations were quantified using enzyme-linked immunosorbent assays. Capsulated Malassezia yeasts stimulated limited or no production of inflammatory cytokines, and increased intracellular IL-10 (P < 0.05). Removal of the capsule of many Malassezia preparations caused a significantly increased production of IL-6, IL-8 and IL-1alpha, and a decrease in intracellular IL-10. Notably, acapsular viable, stationary phase M. globosa caused a 66-fold increase in IL-8 production (P < 0.001) and acapsular nonviable, stationary phase M. furfur caused a 38-fold increase in IL-6 production (P < 0.001) and a 12-fold decrease in intracellular IL-10 (P < 0.001). These results support the hypothesis that the lipid layer of Malassezia spp. modulates cytokine production by keratinocytes. This has implications in the pathogenesis of seborrhoeic dermatitis.
Dandruff and seborrheic dermatitis (D/SD) are common hyperproliferative scalp disorders with a similar etiology. Both result, in part, from metabolic activity of Malassezia globosa and Malassezia restricta, commensal basidiomycete yeasts commonly found on human scalps. Current hypotheses about the mechanism of D/SD include Malassezia-induced fatty acid metabolism, particularly lipase-mediated breakdown of sebaceous lipids and release of irritating free fatty acids. We report that lipase activity was detected in four species of Malassezia, including M. globosa. We isolated lipase activity by washing M. globosa cells. The isolated lipase was active against diolein, but not triolein. In contrast, intact cells showed lipase activity against both substrates, suggesting the presence of at least another lipase. The diglyceride-hydrolyzing lipase was purified from the extract, and much of its sequence was determined by peptide sequencing. The corresponding lipase gene (LIP1) was cloned and sequenced. Confirmation that LIP1 encoded a functional lipase was obtained using a covalent lipase inhibitor. LIP1 was differentially expressed in vitro. Expression was detected on three out of five human scalps, as indicated by reverse transcription-PCR. This is the first step in a molecular description of lipid metabolism on the scalp, ultimately leading toward a test of its role in D/SD etiology.
Fungi in the genus Malassezia are ubiquitous skin residents of humans and other warm-blooded animals. Malassezia are involved in disorders including dandruff and seborrheic dermatitis, which together affect >50% of humans. Despite the importance of Malassezia in common skin diseases, remarkably little is known at the molecular level. We describe the genome, secretory proteome, and expression of selected genes of Malassezia globosa. Further, we report a comparative survey of the genome and secretory proteome of Malassezia restricta, a close relative implicated in similar skin disorders. Adaptation to the skin environment and associated pathogenicity may be due to unique metabolic limitations and capabilities. For example, the lipid dependence of M. globosa can be explained by the apparent absence of a fatty acid synthase gene. The inability to synthesize fatty acids may be complemented by the presence of multiple secreted lipases to aid in harvesting host lipids. In addition, an abundance of genes encoding secreted hydrolases (e.g., lipases, phospholipases, aspartyl proteases, and acid sphingomyelinases) was found in the M. globosa genome. In contrast, the phylogenetically closely related plant pathogen Ustilago maydis encodes a different arsenal of extracellular hydrolases with more copies of glycosyl hydrolase genes. M. globosa shares a similar arsenal of extracellular hydrolases with the phylogenetically distant human pathogen, Candida albicans, which occupies a similar niche, indicating the importance of host-specific adaptation. The M. globosa genome sequence also revealed the presence of mating-type genes, providing an indication that Malassezia may be capable of sex.
• fungal genomics
• fungal proteomics
• seborrheic dermatitis
• skin
• fungal mating
Dandruff and seborrheic dermatitis (D/SD) share an etiology dependent upon three factors: sebum, microbial metabolism (specifically, Malassezia yeasts), and individual susceptibility. Advances in microbiological and analytical techniques permit a more detailed understanding of these etiologic factors, especially the role of Malassezia. Malassezia are lipid-dependent and demonstrate adaptation allowing them to exploit a narrow niche on sebum-rich skin. Work in our and our collaborators' laboratories has focused on understanding these adaptations by detailed analysis of biochemistry and gene expression. We have shown that Malassezia globosa and M. restricta predominate on dandruff scalp, that oleic acid alone can initiate dandruff-like desquamation, that M. globosa is the most likely initiating organism by virtue of its high lipase activity, and that an M. globosa lipase is expressed on human scalp. Considering the importance of M. globosa in D/SD (and the overall importance of commensal fungi), we have sequenced the M. globosa and M. restricta genomes. Genomic analysis indicates key adaptations to the skin environment, several of which yield important clues to the role Malassezia play in human disease. This work offers the promise of defining new treatments to D/SD that are targeted at changing the level or activities of Malassezia genes.
Background: Acne vulgaris is a chronic inflammatory disease of the pilosebaceous unit. Keratinocytes and sebocytes are the two major cell types involved in the induction of acne within the pilosebaceous unit. Thus, keratinocytes or sebocytes cultured alone may not accurately reflect the physiology of the acne lesion. Objective: The aim of this study was to examine inflammatory cytokine production and neutral lipid content in keratinocyte and sebocyte co-cultures treated with acne etiologic stimulants. Methods: Spontaneously immortalized, non-tumorigenic human HaCaT keratinocytes and immortalized human facial SZ95 sebocytes were seeded in 24-well culture plates (Nunc, Wiesbaden, Germany). Secretion of inflammatory cytokines by each cell type was analyzed by enzyme-linked immunosorbent assay, and neutral lipid production in the cells was measured by Oil Red 0 staining. Cells were then simultaneously treated with multiple stimulants at various concentrations, and triglyceride and interleukin 8 (IL-8) levels were measured. Results: Arachidonic acid, linoleic acid, dihydrotestosterone and P. acnes extract all induced IL-8 production. De novo synthesis of sebaceous lipids was observed more frequently in the keratinocyte/sebocyte co-culture than that in the sebocyte monoculture. Higher levels of IL-8 were detected in the multi-stimulant system than those in the mono stimulant system. Conclusion: The results suggest that co-culture of keratinocytes and sebocytes is more representative of me clinical condition associated with the development of acne lesions than culture of either cell type alone. The co-culture system used in this study is applicable to research acne vulgaris pathogenesis and to screen active drugs for treating this condition.
Essential oil of Mentha arvensis L. was fractionated to obtain L-menthol, dementholated oil, mentha monoterpenes, menthone, isomenthone and liquid menthol. Seventeen menthol derivatives were synthesized semi-synthetically from menthol by reacting it with different acid chlorides. Eleven of these derivatives are new. Antimicrobial activity of mentha oil isolates, menthol and its derivatives were studied against twelve bacterial and nine fungal strains. Mentha oil isolates displayed significant inhibition of microbes.
Background. Seborrheic dernnatitis (SD) is a frequent complication of infection with the human immunodeficiency virus (HIV). Most studies examining the cause of SD have concentrated on the roles of Pityrosporum ovale and sebaceous lipids. Previous studies of skin surface lipid from patients with SD have produced conflicting results, with some authors reporting an abnormal lipid composition and others finding little or no abnormality.
Methods. The composition of skin surface lipid was studied in 15 HIV-positive and 10 HIV-negative men with SD, in 14 HIV-positive men without SD, and in 16 unaffected controls. Total lipids were extracted from unaffected forehead skin into petroleum ether and separated into lipid classes by thin layer chromatography. The lipid classes were quantitated by densitometry after charring with sulfuric acid.
Results. Patients, HIV-positive with SD, had significantly lower proportions of free fatty acid (FFA) and higher levels of triglyceride than normal controls. Patients, HIV-positive without SD, had a significantly increased proportion of FFA compared to HIV-positive patients with SD. Patients with SD, both HIV-positive and HIV-negative, had a similar pattern of skin surface lipid. Levels of FFA were lower and those of triglyceride higher than in the patients unaffected by SD, whether HIV-positive or not. There was no significant difference found between groups in free cholesterol, wax esters, and squalene.
Conclusions. Abnormalities of skin surface lipid composition may play a part in the development of SD in both HIV-positive and HIV-negative men.
From their original description, fungi of the genus Malassezia (previously Pityrosporum) have been associated with dandruff and seborrhoeic dermatitis. The principle evidence on which this connection was based was that the organisms were present, often in high numbers, on the skin in these conditions and that both responded to treatment that inhibited or destroyed Malassezia yeasts. The availability of new tools such as genomic and proteomic analyses has begun to provide a new insight into the pathogenetic mechanisms involved. New evidence shows the production of specific phospholipases on affected skin sites in dandruff and signalling molecules such as malassezin in seborrhoeic dermatitis. It is still not clear why those individuals and skin sites, prone to either disease, are particularly associated with the presence of these marker molecules but these studies are providing clues to the different ways in which organisms, which are normally commensals, interact with human skin.
The purpose of this study was to analyse the major compound in the leaf essential oil of Cinnamomum osmophloeum Kaneh. and to examine its in vivo toxicity and cytokine-modulatory effects. The HS-GC/MS and quantitative HPLC analyses showed the concentrations of the major compounds, cinnamaldehyde, benzaldehyde and 3-phenylpropionaldehyde, in the leaf essential oil of Cinnamomum osmophloeum to be 16.88, 1.28 and 1.70 mg/mL, respectively. Acute and sub-acute toxicity tests identified no significant changes in body weight, liver and kidney function indices, and pathology for the mice treated with up to 1 mL/kg body weight of Cinnamomum osmophloeum leaf essential oil or up to 4 mg/kg body weight of cinnamaldehyde. A murine model was established using ovalbumin (OVA)-primed Balb/C mice treated with various concentrations of Cinnamomum osmophloeum leaf essential oil or cinnamaldehyde daily for 4 weeks. The results of tests with commercial ELISA kits indicated no significant cytokine-modulatory effects in mice treated with Cinnamomum osmophloeum leaf essential oil; however, the serum concentrations of IL-2, IL-4 and IL-10, but not IFN-γ, significantly increased in animals treated with 1 mg/kg body weight of cinnamaldehyde during the 4-week period. The possibility that the other constituents act as antagonists of cinnamaldehyde cannot be excluded.
Interest in sebaceous gland physiology and its diseases is rapidly increasing. We provide a summarized update of the current knowledge of the pathobiology of acne vulgaris and new treatment concepts that have emerged in the last 3 years (2005-2008). We have tried to answer questions arising from the exploration of sebaceous gland biology, hormonal factors, hyperkeratinization, role of bacteria, sebum, nutrition, cytokines and toll-like receptors (TLRs). Sebaceous glands play an important role as active participants in the innate immunity of the skin. They produce neuropeptides, excrete antimicrobial peptides and exhibit characteristics of stem cells. Androgens affect sebocytes and infundibular keratinocytes in a complex manner influencing cellular differentiation, proliferation, lipogenesis and comedogenesis. Retention hyperkeratosis in closed comedones and inflammatory papules is attributable to a disorder of terminal keratinocyte differentiation. Propionibacterium acnes, by acting on TLR-2, may stimulate the secretion of cytokines, such as interleukin (IL)-6 and IL-8 by follicular keratinocytes and IL-8 and -12 in macrophages, giving rise to inflammation. Certain P. acnes species may induce an immunological reaction by stimulating the production of sebocyte and keratinocyte antimicrobial peptides, which play an important role in the innate immunity of the follicle. Qualitative changes of sebum lipids induce alteration of keratinocyte differentiation and induce IL-1 secretion, contributing to the development of follicular hyperkeratosis. High glycemic load food and milk may induce increased tissue levels of 5alpha-dihydrotestosterone. These new aspects of acne pathogenesis lead to the considerations of possible customized therapeutic regimens. Current research is expected to lead to innovative treatments in the near future.
The antibacterial activity of 14 essential oils and their major constituents in the gaseous state was evaluated against Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus. For most essential oils examined, H. influenzae was most susceptible, followed by S. pneumoniae and S. pyogenes, and then S. aureus. Penicillin-susceptible and -resistant S. pneumoniae were comparable in susceptibility. Escherichia coli, which was used as a control, showed least susceptibility. A minimal inhibitory dose (MID) was introduced as a measure of
the vapour activity. Among 14 essential oils, cinnamon bark, lemongrass and thyme oils showed the lowest MID, followed by
essential oils containing terpene alcohols as major constituents. The essential oils containing terpene ketone, ether and,
in particular, hydrocarbon had high MIDs. The vapour activity on short exposure was comparable to that following overnight
exposure, and rapid evaporation was more effective than slow evaporation of essential oils. The vapour concentration and absorption
into agar of essential oils reached a maximum 1 or 2 h after rapid evaporation. These results indicate that the antibacterial
action of essential oils was most effective when at high vapour concentration for a short time.
Yeasts of Malassezia, members of the microbiologic flora of the skin, cause pityriasis versicolor and have also been implicated in the pathogenesis of other superficial dermatoses; the most important ones are seborrheic dermatitis, folliculitis, and atopic dermatitis. The mechanisms by which the yeasts cause these dermatoseş however, are not yet clear, and there have been no studies on the interaction between fungi and keratinocytes, especially the effects of fungi on the production of cytokines by human keratinocytes. Recently, the genus Malassezia has been expanded to seven species based on molecular data. In this study, we estimated the effects of Malassezia yeasts on cytokine (interleukins 1beta, 6, and 8, monocyte chemotactic protein-1, and tumor necrosis factor-alpha) production by human keratinocytes in order to examine whether the pathogenicity of the respective Malassezia yeasts is different from each other and to elucidate the mechanism by which Malassezia yeasts cause the dermatoses with different clinical and pathologic manifestations. Variable levels of interleukin 6 and 8, and tumor necrosis factor-alpha in the supernatants in response to Malassezia yeasts (except M. furfur) increased from 1 to 24 h co-culture, but the monocyte chemotactic protein-1 was undetectable. Furthermore, cytokine levels in the supernatants were undetectable 1-24 h after the keratinocytes were harvested with only supernatants of Malassezia. These results indicate that Malassezia stimulates cytokine production by keratinocytes, the cytokine production needs the presence of Malassezia, and there are differences in ability to induce cytokine production by human keratinocytes among Malassezia yeasts. These differences may reflect the different inflammatory responses in Malassezia-associated dermatoses, resulting in different clinical and pathologic manifestations.
Seborrhoeic dermatitis is a disease of unknown etiopathogenesis that affects 5% of the population. In this study, we investigated expression of mRNA for IL-1 alpha, IL-6, IL-4, IFN-gamma, and the stress-inducible MICA molecule in skin biopsies from 12 patients with moderate to severe seborrhoeic dermatitis and 2 healthy volunteers by RT-PCR and hybridization with specific probes. Eight patients expressed INF-gamma, 2 expressed IL-6, 8 expressed IL-1 alpha, and 2 expressed IL-4 (1 with moderate disease). Eight patients expressed inflammatory cytokines (IL-1 alpha, IL-6, and/or IFN-gamma) in healthy skin. Higher cytokine mRNA in damaged vs healthy skin was also observed, suggesting the existence of an inflammation that predisposes healthy skin to develop overt disease. Up-regulated expression of MICA mRNA was observed in 8 patients. Although the pathogenesis of seborrhoeic dermatitis remains to be elucidated, expression of cytotoxicity-activating ligands (MICA), recruitment of NK cells, and a local pro-inflammatory microenvironment may facilitate the development of tissue injury.
Androgens have profound effects on the physiology of the sebaceous gland. Using the hamster ear sebaceous gland model, we performed a detailed kinetic study to clarify the mechanism of androgen action on sebaceous gland function. We demonstrated that the growth of sebaceous glands observed after androgen treatment was due to both an increase in sebocyte proliferation and a parallel induction of sebocyte terminal differentiation, as evidenced by the induction of the synthesis of specific sebaceous lipids such as cholesterol esters, triglycerides, and squalene. Accordingly, the effect of androgen treatment on the mRNA expression of several key enzymes involved in the synthesis of sebaceous lipids has been studied using semi-quantitative RT-PCR. Up-regulation by androgens of mRNA expression of HMG coenzyme A synthase and reductase, acetyl coenzyme A carboxylase (ACC), glycerol 3-phosphate acyl transferase (GPAT), and FAR-17c (stearoyl coenzyme A desaturase homologous), was demonstrated. Because sterol-response element(s) (SREs) are known to be present in the promoters of these genes, we analyzed the expression by RT-PCR and the activation of the transcription factor sterol regulatory element binding protein (SREBP) using immunoblotting experiments. Our results showed that SREBP-1 was up-regulated and rapidly activated after androgen treatment. Altogether, these results demonstrate for the first time that in sebaceous glands, in vivo, androgen regulates the synthesis of sebum lipids through the SREBP pathway.
TABLE OF CONTENTS Introduction 4 History and taxonomy of the genus Malassezia 5 Biological characteristics of Malassezia organisms 5 Structure 5Reproduction 6Biochemistry 6Distribution of Malassezia organisms on the host 6 Immunological and epidermal responses to Malassezia organisms 7 The immune response to Malassezia organisms 7 Antigen release, penetration and presentation 8Cell-mediated immune responses 8IgG, IgM and IgA responses to Malassezia organisms 9 IgE responses to Malassezia organisms 10 Mast cell responses 11Epidermal responses associated with Malassezia dermatitis 12 Malassezia organisms as pathogens in humans and animals 13 Diseases associated with Malassezia spp. in humans 13 Pityriasis versicolor 13Malassezia folliculitis 13 Seborrheic dermatitis and dandruff 14Atopic dermatitis 14Malassezia fungaemia 14 Diseases associated with Malassezia spp. in animals 15 Malassezia dermatitis in dogs 15 Predisposing factors for overgrowth of Malassezia pachydermatis 15 Pathogenesis 16Clinical features 16Diagnosis 17Treatment 18Conclusions 19 References 19
Hormones influence the development and function of human skin which also produces and releases hormones. Recently attention has been focused on identifying and understanding the complex endocrine properties of human skin, such as expression and function of specific hormone receptors, synthesis of hormones from major classes of compounds used by the body for general purposes, organized metabolism, activation, inactivation and elimination of the hormones in specialized cells of the tissue, exertion of biological activity and release of tissue hormones in the circulation. Specifically, hormones exert their biological effects on the skin through interaction with high-affinity receptors, such as several receptors for peptide hormones and neurotransmitters, steroid and thyroid hormones. Hormones exhibit a wide range of biological activities on the skin with distinct effects caused by growth hormone/insulin-like growth factor-I, neuropeptides, sex steroids, glucocorticoids, retinoids, vitamin D, peroxisome proliferator-activated receptor ligands, eicosanoids, melatonin and serotonin. Human skin produces, activates or inactivates metabolically numerous hormones which are probably important for skin functions but also for functions of the entire human organism, such as sex hormones, especially in aged individuals, insulin-like growth factor and -binding proteins, neuropeptides, prolactin, catecholamines, retinoids, steroids, vitamin D and eicosanoids. These functions are undertaken in most cases by different skin cell populations in a coordinated way, indicating the endocrine autonomy of the skin. Characteristic examples are the metabolic pathways of the corticotropin-releasing hormone/propiomelanocortin axis, steroidogenesis, vitamin D and retinoids. The human skin is, thus, the largest, peripheral endocrine organ.
Despite the clinical evidence that androgens stimulate sebaceous lipids, androgens in vitro have shown no similar effects. This contradiction led to the assumption that cofactors may be required for lipid regulation and peroxisome proliferator-activated receptor (PPAR) ligands were suggested to be adequate candidates.
The influence of testosterone and linoleic acid, a PPAR ligand, as single agents and in combination with of LY191704, a 5alpha-reductase type I inhibitor, was examined on 5alpha-dihydrotestosterone (5alpha-DHT) synthesis and lipid content in human SZ95 sebocytes.
Cell proliferation and viability were measured by the 4-methylumbelliferyl heptanoate fluorescence assay and by the Boehringer Lactate Dehydrogenase Assay kit, respectively. 5alpha-DHT enzyme-linked immunosorbent assay was used for the detection of 5alpha-DHT synthesis in cell supernatants after treatment, whereas lipid production was documented by means of the Nile red lipid microassay and fluorescence microscopy.
Testosterone promoted 5alpha-DHT synthesis (P < 0.001), whereas linoleic acid increased sebaceous lipids (P < 0.001). The combination of testosterone and linoleic acid exhibited a synergistic effect on the synthesis of 5alpha-DHT (P < 0.01 vs. testosterone) and sebaceous lipids (P < 0.01 vs. linoleic acid). Furthermore, LY191704 reduced 5alpha-DHT and sebaceous lipid levels (P < 0.01 and P < 0.001 in comparison with testosterone/linoleic acid, respectively). Cell proliferation and viability remained unchanged under treatment with all compounds tested.
These data suggest a catalytic effect of PPAR ligands on cellular testosterone activation by 5alpha-reduction and the importance of the latter for the regulation of sebaceous lipids.
In this study, chemical compositions of hydrodistilled essential oil and anti-inflammatory activities from the twigs of Cinnamomum osmophloeum Kaneh. were investigated for the first time. The chemical constituents of the twig essential oil were further analyzed by GC-MS and they were found to be L-bornyl acetate (15.89%), caryophyllene oxide (12.98%), gamma-eudesmol (8.03%), beta-caryophyllene (6.60%), T-cadinol (5.49%), delta-cadinene (4.79%), trans-beta-elemenone (4.25%), cadalene (4.19%), and trans-cinnamaldehyde (4.07%). The effects of essential oil on nitric oxide (NO) and prostaglandin E2 (PGE2) production in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages were also examined. Results of nitric oxide tests indicated that twig essential oil and its major constituents such as trans-cinnamaldehyde, caryophyllene oxide, L-borneol, L-bornyl acetate, eugenol, beta-caryophyllene, E-nerolidol, and cinnamyl acetate have excellent activities. These findings demonstrated that essential oil of C. osmophloeum twigs have excellent anti-inflammatory activities and thus have great potential to be used as a source for natural health products.
This was a preliminary investigation to define the conditions of colonization of a human skin equivalent (SE) model with cutaneous microorganisms. SEs of 24 mm diameter were constructed with a dermal matrix of fibrin containing fibroblasts and a stratified epidermis. Microbial colonization of the SEs was carried out in a dry environment, comparable to 'in vivo' skin, using a blotting technique to remove inoculation fluid. The microbial communities were sampled by scrub washing and viable cells enumerated on selective growth medium. Staphylococcus epidermidis, Propionibacterium acnes and Malassezia furfur (human skin commensals) and Staphylococcus aureus (transient pathogen) were colonized at inoculum densities of 10(2)-10(6) CFU SE(-1) on the surface of replicate SEs. Growth of all species was supported for upto 72-120 h, with recovery densities of between 10(4)-10(9) CFU SE(-1). A novel, real-time growth monitoring method was also developed, using S. aureus containing a lux cassette. Light output increased from 20 to 95 h, and colonization increased from 10(2) to 10(8) CFU SE(-1), as confirmed by conventional recovery. Thus, the SE model has potential to investigate interactions between resident and transient microbial communities with themselves and their habitat, and for testing treatments to control pathogen colonization of human skin.
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Testosterone and linoleic acid exhibited a synergistic effect on the synthesis of sebaceous lipids
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Dandruff-associated Malassezia genomes reveal convergent and divergent virulence traits shared with plant and human fungal pathogens
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New developments in our understanding of acne pathogenesis and treatment
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