Piérard Ge

Influence of the Test Area on the Mechanical Properties of Skin

BACKGROUND New advances in bioengineering have provided commercially available devices for measuring the mechanical properties of skin in vivo. Reproducibility of data and methodological approaches have not yet been thoroughly studied. OBJECTIVE To study the reproducibility and the influence of the area of the test site on the values of biomechanical variables yielded in a normal population. METHOD A 500-mbar suction was transmitted to the skin through Cutometer probes equipped with a 2- or 8-mm opening. RESULTS The best reproducibility was obtained for the maximum distension of skin and for the biological elasticity. The values of the standard biomechanical ratios were almost the same for both probes. Linear correlations were found between parameters of elasticity. CONCLUSION The Cutometer is a reliable device. A high degree of correlation exists between biomechanical variables related to elasticity. Under a suction of 500 mbar, both the 2- and 8-mm probes give results which correlate statistically in a large population. However, the two probes do not measure precisely the same aspect of skin mechanics. The 2-mm probe measures the capacity of superficial skin folding, and the 8-mm probe explores the biomechanical properties of the dermis itself and of its slipping mobility on the hypodermis. The biomechanical parameters which appear the most clinically relevant for a normal-looking skin are the maximum distension and the biological elasticity.

Unraveling the Patterns of Subclinical Pheomelanin-Enriched Facial Hyperpigmentation: Effect of Depigmenting Agents

Background: During photoaging, the density of melanin chromatophores is heterogeneous in the epidermis. Aims: To define the patterns of pheomelanin-enriched melanotic hypermelanosis of the face in phototype II subjects and to assess the effect of depigmenting agents. Azelaic acid and glycolic acid were tested as well as a soy extract, reported to reduce pigmentation through interaction with the protease-activated receptor 2 (PAR-2) of keratinocytes. Method: Evaluations were made by image analysis of high magnification pictures obtained by a video camera equipped with an internal ultraviolet-emitting unit (Visioscan®). Results: Three patterns of subclinical facial hypermelanosis were recognized including the spotty perifollicular type, the accretive globular type and the elongated type of the sunny side of wrinkles. Azelaic acid and the soy extract led to significant skin lightening after a 3-week treatment. By contrast, glycolic acid showed an inconsistent effect. Conclusion: Sensitive fluorescence video recording combined with image analysis represents an advance in the noninvasive assessment of the mottled subclinical skin pigmentation. The depigmenting effect observed with the soy extract indicates that the inhibition of PAR-2 may be a novel way to approach certain pigmentary disorders of the skin.

The Beneficial Toxicity Paradox of Antimicrobials in Leg Ulcer Healing Impaired by a Polymicrobial Flora: A Proof-of-Concept Study

Background: Some of the views contrasting the beneficial and toxic effects of antimicrobials upon wound healing remain controversial. Objective: To assess the clinical relevance of histological findings following antimicrobial applications on chronic leg ulcers. Method: The present study was performed in three parallel groups of 17 patients suffering from at least 2 similar chronic leg ulcers. Clinical planimetric assessments were performed before and after 3 and 6 weeks of treatment using hydrocolloid dressings. In addition, 1 ulcer in each patient received applications of povidone-iodine (PVP-I), silver sulfadiazine or chlorhexidine digluconate. Histological examinations were made at inclusion and after the 6-week therapy. Time to healing was also recorded. Results: At entry in the study, fibroblasts, macrophages, neutrophils and vessels were abundant in the ulcers. In addition, focal necrotizing vasculitis was related to the microbiological load. Compared to the control lesions, both the healing rate and time to healing of the leg ulcers showed a modest improvement at the sites receiving silver sulfadiazine (2–7%) or chlorhexidine digluconate (–1 to 5%). By contrast, PVP-I increased significantly the healing rate (4–18%, p < 0.01), and time to healing was reduced by 2–9 weeks (p < 0.01). The 3 antimicrobials decreased the bacterial density, and the vascular margination and migration of inflammatory cells, thus abating the vasculitic changes. PVP-I applications did not alter the microvessels and did not significantly reduce the density in dendrocytes and fibroblasts. By contrast, both silver sulfadiazine and chorhexidine digluconate appeared to alter the superficial microsvasculature including the dendrocyte population. Conclusion: Although topical antimicrobials may apparently achieve almost similar activity on the bacterial load inside chronic leg ulcers, the toxicity upon host cells was different among these agents. PVP-I appeared to be an efficient compound in these respects exhibiting a positive and relevant clinical effect.

From axioms to new insights into dandruff.

This review addresses the current concepts about dandruff. The nature, origin and treatments of such skin conditions are scrutinized. The role of Malassezia spp. and other triggering factors is highlighted.

Ketoconazole Shampoo: Effect of Long-Term Use in Androgenic Alopecia

Background: The pathogenesis of androgenic alopecia is not fully understood. A microbial-driven inflammatory reaction abutting on the hair follicles might participate in the hair status anomaly. Objective: The aim of our study was to determine if ketoconazole (KCZ) which is active against the scalp microflora and shows some intrinsic anti-inflammatory activity might improve alopecia. Method: The effect of 2% KCZ shampoo was compared to that of an unmedicated shampoo used in combination with or without 2% minoxidil therapy. Results: Hair density and size and proportion of anagen follicles were improved almost similarly by both KCZ and minoxidil regimens. The sebum casual level appeared to be decreased by KCZ. Conclusion: Comparative data suggest that there may be a significant action of KCZ upon the course of androgenic alopecia and that Malassezia spp. may play a role in the inflammatory reaction. The clinical significance of the results awaits further controlled study in a larger group of subjects.

Collision of primary malignant neoplasms on the skin: the connection between malignant melanoma and basal cell carcinoma.

Several studies have reported the association of cutaneous malignant melanomas (MM) with carcinomas. Collision malignancies cases from our files were retrieved. Among a series of 78,000 primary cutaneous cancers, 11 were collision tumors of MM with basal cell carcinoma and 106 were basosquamous carcinomas while no association was found between MM and squamous cell carcinomas. It is concluded that coexisting and confluent malignancies of the skin might not always be a random event.

Cellulite histopathology and related mechanobiology

Cellulite, sometimes called gynoid lipodystrophy, is much more prevalent in women than in men. There are glaring discrepancies regarding the microanatomical descriptions of this condition in the literature. A lumpy aspect of the dermo‐hypodermal interface is often cited, but it appears to represent a gender‐linked characteristic of the thighs and buttocks without being a specific sign of cellulite. Incipient cellulite recognized by a discrete padded look or ‘orange peel’ aspect appears correlated with the presence of a network of focally enlarged fibrosclerotic strands partitioning the hypodermis and serving as a physiological buttress limiting the outpouching of fat lobules on pinching the skin. These connective tissue structures might represent a hormonal‐dependent reactive process to sustained mechanical tensions caused by the adipocyte lobules. Full blown cellulite is recognized by a lumpy‐bumpy and dimpled skin surface. It likely represents subjugation of the hypertrophic response of the hypodermal connective tissue strands when their resistance is overcome by progressive fat accumulation. In these cases, histological aspects reminiscent of striae distensae are identified within the hypodermal connective tissue strands. The mechanical properties of skin involved by cellulite process are altered, but may tend to resume to normal under treatment. These functional changes influence the mechanobiology of connective tissue cells, in particular the Factor XIIIa‐positive dermal dendrocytes.

Assessment of Topical Hypopigmenting Agents on Solar Lentigines of Asian Women

Background: So-called darkened age spots encompass distinct pathological processes. The efficacy of topical depigmenting agents is difficult to objectivate. Objective: To assess the hypopigmenting effect of three cosmetic formulations using objective biometrological methods. Methods: 50 women of South-East Asian ancestry were enrolled in this pilot study. They had solar lentigines according to dermoscopic criteria. The lesions were treated by topical hypopigmenting formulations. Products were applied twice daily for 2 or 3 months. Assessments at 1-month intervals were made using narrow-band reflectance spectrophotometry, image analysis of video-recorded ultraviolet light reflection and photodensitometry- and image-analysis-assisted corneomelametry. Results: A 20% azelaic acid formulation and another one containing 5% ascorbyl glucosamine, 1% kojic acid and α-hydroxyacid esters appeared inefficacious on solar lentigines. A stabilized soy extract showed a better although modest lightening effect when assessed by corneomelametry. The subclinical or faint mottled skin revealed by ultraviolet light examination better responded (p < 0.05) to treatments. Conclusion: Focal epidermal hyperpigmentation is better controlled by topical whitening agents when the increase in melanin content reflects a modest functional hyperactivity of melanocytes.

Treatment and Prophylaxis of Tinea Infections

SummarySuperficial fungal infections affect millions of people throughout the world. Among them, tinea represents cutaneous infections by dermatophytes. Therapeutic strategies depend upon the affected body site. Hence, clinicians distinguish several types of tinea including the corporis, faciei, cruris, pedis, manuum, capitis, barbae and unguium variants. There are several ways of tackling the tinea problem. Numerous topical and oral antifungals are available today. Topical antifungals remain the most commonly recommended treatment for many superficial dermatophytoses. Active compounds include imidazoles, morpholines and allylamines, with a few other miscellaneous drugs. The recent development of new generation oral agents (fluconazole, itraconazole, terbinafine) has enhanced the armamentarium against difficult-to-treat tineas. The antifungal efficacy and pharmacokinetic profiles of these drugs allow shorter durations of treatment and the innovative use of intermittent pulse regimens. The modern formulations fully meet the requirements of being well tolerated, involving little risk and acting specifically against relevant pathogens. However, the response rates to date do not always come up to the high expectations offered by in vitro studies.

Antifungal activity of itraconazole and terbinafine in human stratum corneum: A comparative study

BACKGROUND The evaluation of antifungal agents by in vitro and animal experiments cannot predict clinical efficacy with certainty. New models are needed to assess and compare antifungal activity. OBJECTIVE We compared on human stratum corneum ex vivo the antifungal activity and lingering effect of 200 mg itraconazole daily and twice daily, and 250 mg/day terbinafine. METHODS Three groups of 10 healthy volunteers entered the open comparative trial. Results were evaluated in a blinded manner. Cyanoacrylate skin surface strippings (CSSS) were taken from the back and superficial dermatome skin samples (SDSS) were taken from plantar skin at days 0, 1, 3, 7, 8, 10, 14, 21, 28, and 35. Spores or yeasts of selected fungi (Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, and Candida albicans) were deposited and cultured on the CSSS and SDSS. The 1-week fungal growth on CSSS and SDSS was assessed over time by computerized image analysis to derive the inhibitory effect of the oral antifungal agents administered. Fungitoxic activity was also assessed by the use of 2-day cultures on CSSS followed by a transfer to Sabouraud medium. RESULTS Comparable antifungal activity against dermatophytes was found for all three regimens. Itraconazole at both dosages was always significantly more active than terbinafine against C. albicans on CSSS and SDSS. Overall, 200 mg itraconazole twice daily appeared to be more fungitoxic than 250 mg/day terbinafine and 200 mg/day itraconazole. CONCLUSION The ex vivo culture of fungi on human stratum corneum is very similar to the in vivo situation. Both itraconazole and terbinafine display high antidermatophyte activity. Faster onset and longer posttherapy activity were demonstrated in the itraconazole treatment groups. Terbinafine had marginal activity against C. albicans in this model.