Changes in epidermal morphology associated with dandruff.

OBJECTIVE: Dandruff is a very common scalp condition characterized by flaking and pruritus usually with no visible signs of inflammation, such as redness and erythema. Dandruff is considered a multifactorial condition with both microbial colonization and host factors such as sebum production thought to play a role. There is evidence of changes in epidermal morphology in the scalp skin of dandruff sufferers, with reports of an increase in mean thickness and more nucleated cell layers. The underlying mechanisms driving these morphological changes are currently unclear. The objective of this study was to fully characterize epidermal morphology in dandruff compared to healthy scalp skin and to evaluate potential mechanisms underlying any changes observed. METHODS: Scalp skin biopsies were taken from 22 healthy female subjects and 21 dandruff sufferers, from both lesional and non-lesional sites. Samples were processed, sectioned and stained using haematoxylin and eosin (H&E). To fully characterize epidermal morphology, measurements were taken of epidermal thickness, the convolution of the dermal-epidermal junction and the depth of epidermal rete ridges. To analyse changes in epidermal proliferation immunohistochemical staining was performed using Ki67, a well-established marker of cell proliferation, and quantified using image analysis. RESULTS: Histochemical analysis of skin sections revealed that in dandruff lesional samples, the epidermis was thicker, had a more convoluted dermal epidermal junction and the rete ridges were elongated, compared to healthy scalp skin. Similar directional changes in epidermal morphology, were observed in non-lesional dandruff samples, albeit to a lesser extent. Image analysis of Ki67 expression in the epidermis revealed dandruff lesional skin contained significantly more Ki67-positive proliferating keratinocytes than healthy controls samples. This suggests dandruff scalp skin epidermal keratinocytes are in a hyper-proliferative state. CONCLUSION: There were significant changes in epidermal morphology in dandruff lesional skin compared to healthy scalp skin including increased epidermal thickness, a more convoluted dermal-epidermal junction and elongation of rete ridges. Interestingly, we found there was evidence of an increase in the percentage of epidermal Ki67-positive cells, which has not been reported previously, and demonstrates dandruff is a condition displaying epidermal hyper-proliferation.

OBJECTIF: Les pellicules constituent une affection du cuir chevelu très fréquente caractérisée par une desquamation et un prurit ne présentant pas, en général, des signes visibles d'inflammation, comme une rougeur et un érythème. Les pellicules sont considérées être une affection multifactorielle présentant une colonisation microbienne ainsi que des facteurs-hôtes, tels que la production de sébum, qui pourraient avoir un rôle à jouer. Il existe des preuves qu'il se produit des changements dans la morphologie épidermique de la peau du cuir chevelu des personnes qui ont des pellicules, et des rapports font cas d'une augmentation de l'épaisseur moyenne et d'un plus grand nombre de couches de cellules nucléées. Les mécanismes sous-jacents à ces changements morphologiques sont jusqu'ici peu élucidés. L'objectif de cette étude était de caractériser pleinement la morphologie épidermique en la présence de pellicules par comparaison à la peau du cuir chevelu sain, et d'évaluer les mécanismes potentiels sous-jacents à tout changement observé. MÉTHODES: Des biopsies de la peau du cuir chevelu ont été pratiquées chez 22 femmes en bonne santé et 21 femmes présentant des pellicules, dans des sites lésionnés et non lésionnés. Les échantillons ont été traités, coupés en lamelles et colorés en utilisant de l'hématoxyline et de l'éosine (H&E). Pour caractériser pleinement la morphologie épidermique, des mesures de l'épaisseur épidermique, de la convolution de la jonction dermo-épidermique et de la profondeur des crêtes du réseau épidermique ont été effectuées. Pour analyser les changements dans la prolifération épidermique, une coloration immunohistochimique a été réalisée en utilisant du Ki67, un marqueur bien établi de la prolifération cellulaire, et quantifiée à l'aide de l'analyse d'images. RÉSULTATS: L'analyse histochimique des sections de peau a révélé que, dans les échantillons de lésions avec pellicules, l'épiderme était plus épais, présentait une jonction dermo-épidermique plus compliquée et des crêtes du réseau plus allongées, par comparaison à la peau du cuir chevelu en bonne santé. Des changements directionnels analogues de la morphologie épidermique ont été observés dans les échantillons sans lésions et avec pellicules, toutefois en une moindre mesure. L'analyse des images de l'expression de Ki67 dans l'épiderme a révélé que la peau avec lésions et pellicules contenait des kératinocytes prolifératifs bien plus Ki67-positifs que les échantillons de témoins en bonne santé. Cela suggère que les kératinocytes épidermiques de la peau du cuir chevelu présentant des pellicules sont dans un état hyper-prolifératif. CONCLUSION: Il s'est produit des changements significatifs dans la morphologie épidermique de la peau avec lésions et pellicules, par comparaison à la peau du cuir chevelu en bonne santé, y compris un épaississement de l'épiderme, une jonction dermo-épidermique plus compliquée et un allongement des crêtes du réseau. Fait intéressant, nous avons découvert des signes d'augmentation du pourcentage de cellules épidermiques Ki67-positives, ce qui n'avait encore jamais été rapporté, et qui démontre que la présence de pellicules est une affection affichant une hyper-prolifération épidermique.

Climbazole increases expression of cornified envelope proteins in primary keratinocytes.

OBJECTIVE: Dandruff is a troubling consumer problem characterized by flaking and pruritus of the scalp and is considered a multifactorial condition with sebum, individual susceptibility and the fungus Malassezia all thought to play a part. The condition is commonly treated with shampoo products containing antifungal ingredients such as zinc pyrithione and climbazole. It is hypothesized that these ingredients may be delivering additional scalp skin benefits besides their antifungal activity helping to relieve dandruff effectively. The objective of this study was to evaluate the anti-dandruff ingredient climbazole for potential skin benefits using genomics and in vitro assays. METHODS: Microarray analysis was performed to profile gene expression changes in climbazole-treated primary human keratinocyte cells. Results were independently validated using qPCR and analysis of protein expression using ELISA and immunocytochemistry. RESULTS: Microarray analysis of climbazole-treated keratinocytes showed statistically significant expression changes in genes associated with the gene ontology groups encompassing epidermal differentiation, keratinization, cholesterol biosynthesis and immune response. Upregulated genes included a number encoding cornified envelope proteins such as group 3 late-cornified envelope proteins, LCE3 and group 2 small-proline-rich proteins, SPRR2. Protein analysis studies of climbazole-treated primary keratinocytes using ELISA and immunocytochemistry were able to demonstrate that the increase in gene transcripts translated into increased protein expression of these cornified envelope markers. CONCLUSION: Climbazole treatment of primary keratinocytes results in an upregulation in expression of a number of genes including those encoding proteins involved in cornified envelope formation with further studies demonstrating this did translate into increased protein expression. A climbazole-driven increase in cornified envelope proteins may improve the scalp skin barrier, which is known to be weaker in dandruff. These studies suggest climbazole, besides its antifungal activity, is delivering positive skin benefits helping to relive dandruff symptoms effectively.

Histological evaluation of hyperpigmentation on female Filipino axillary skin.

Females in South East Asia (Thailand, Indonesia and the Philippines) show concern about dark areas of skin which develop in their underarms, but little is known about the features differentiating pale and hyperpigmented axillary skin in the general population. To investigate this, a histology study was undertaken in the Philippines to define the aetiology of underarm darkening, which is postulated to be a mild form of postinflammatory hyperpigmentation (PIHP). Punch biopsies were taken from dark and light axillary skin sites of 20 female subjects, of whom seven had hyperpigmented underarms, based on an instrumental (Mexameter MX-18, Courage and Khazaka Electronic GmbH, Cologne, Germany) measure, and 13 had not. Histological and immunohistochemical analyses were undertaken using a range of stains and antibodies, including haematoxylin-eosin for general histopathology, Masson-Fontana for melanin, anti-CD68 for monocytes and macrophages, Van Gieson's technique for fibrosis, anti-proliferating cell nuclear antigen for cell mitosis, and the melanocyte-specific immunostains, anti-tyrosinase and anti-tyrosinase-related protein 1. In most cases, dark skin sites from hyperpigmented panelists had increased intensity of Masson-Fontana, anti-tyrosinase and/or anti-TRP1 staining, indicative of melanocyte stimulation and increased melanin production. Furthermore, hair plucking emerged as a key stimulus to increased pigmentation. The trauma of hair plucking slightly increased the number of infiltrating mononuclear cells and macrophages that ingested melanosomes leaking from the damaged epidermis, more so in the skin of hyperpigmented panelists; this, in turn, potentially increases pigmentation. However, cell infiltration was focal, mainly near the plucked follicles, and not indicative of diffuse inflammation. The results from this study support the hypothesis that axillary darkening is mild PIHP, characterized by increased epidermal melanin, following stimulation or mild irritation of skin, with hair plucking as a key factor in this process.

Construction of a database of benzene biological monitoring.

Biological monitoring of occupational exposure to benzene has been conducted in the petroleum, steel and chemical industries. The urinary benzene-specific biomarker, S-phenylmercapturic acid (PMA), was quantified in post-shift samples using a sensitive enzyme-linked immunosorbent assay (ELISA) and expressed as a function of urinary creatinine concentration. The assay, based on a PMA-specific antiserum, is sufficiently sensitive to measure PMA levels in non-occupationally exposed control subjects. The assay delivers batch results in a timely manner which may be as short as 3 h. Samples were analysed from groups of workers engaged in coke oven combustion processes, petroleum refining and decontamination of a benzene land spill. The construction of a database of results provides an index of benzene uptake as a consequence of the respective work processes and tasks and readily enables benchmarking exercises aimed at comparing degrees of exposure across segments of industry.

Development and validation of a competitive immunoassay for urinary S-phenylmercapturic acid and its application in benzene biological monitoring.

An immunoassay that quantifies urinary S-phenylmercapturic acid (PMA), a benzenespecific biomarker, has been developed and its potential usefulness as a screening tool for monitoring occupational exposure to benzene has been demonstrated. Analytical reliability has been confirmed by correlation of results with gas chromatography-mass spectrometry (GC/MS) data (R = 0.92). The assay has been configured as a competitive enzyme-linked immunosorbent assay (ELISA) to facilitate rapid throughput of samples. The ELISA has a working range of 40-1200 nmoll-1 urinary PMA and appears to be unaffected by the presence of structurally related urinary metabolites. Background levels of 0-1.9 mumol PMA/mol creatinine (mean 0.9 mumol mol-1, n = 32) were measured in nonsmoking control subjects. Recent exposures to benzene (8 h time-weighted averages-TWA), during diverse industrial processes, over the range 0-4.8 ppm were identified by application of the assay in biological monitoring programmes.