Characterisation of Cutibacterium acnes phylotypes in acne and in vivo exploratory evaluation of Myrtacine®

OBJECTIVE : Our main objective was to compare Cutibacterium acnes (C. acnes) skin colonisation in patients with mild to moderate acne versus healthy controls and secondly, to evaluate a Myrtacine® -based cream on C. acnes total population and antibioresistant Cutibacteria in patients with acne. METHODS:In 60 acne patients (Global Acne Severity Scale, GEA grades 2-3), of mean age 20 [15-30] years and in 24 age- and sex- matched healthy controls, forehead strips samplings were performed for microbiological analysis of comedones by colony forming unit (CFU) counts of global C. acnes and erythromycin (EryR) or clindamycin-resistant (ClnR) populations of Cutibacterium and determination of phylotypes by MALTI-TOF. Clinical evaluations of acne patients (GEA, lesion count, porphyrin fluorescence) were performed at baseline and after 56 days of twice-daily application of a Myrtacine® -based cream. RESULTS : We first showed (i) high and similar levels of C. acnes colonisation in superficial pilosebaceous follicles and detection of EryR and ClnR strains in both acne and control groups; (ii) different repartition of phylotypes in acne patients versus healthy control, with a predominance of phylotype IA in acne patients and a link between phylotype IA and erythromycin resistance. Besides, after treatment with the Myrtacine® -based cream in acne patients, there was no change in C. acnes total load, but a significant decrease of EryR Cutibacteria, reduced porphyrin production by C. acnes, a decrease in acne severity (GEA), associated with reduced retentional and inflammatory lesions. CONCLUSION : Cutibacterium acnes colonisation was not significantly different in acne versus control groups. Phylotype IA was predominant in acne patient and in EryR C. acnes. A Myrtacine® -based cream significantly reduced the level of EryR Cutibacteria in vivo and improved acne lesions

Dermatite atopique et évaluation d'un soin émollient

La dermatite atopique est l'affection dermatologique la plus fréquente chez le nourrisson. Elle touche 2 à 3 % de la population française. Les causes et les mécanismes de cette maladie sont encore très controversés. Après un rappel sur les différentes structures de la peau, les principes de la maladie et le disfonctionnement de la barrière cutanée ou stratum corneum seront envisagés. La prise en charge de cette maladie sera exposée, détaillant les rôles des émollients et des nouvelles thérapeutiques immunosuppressives. Enfin, les méthodes d'évaluation d'un soin émollient destiné à des peaux atopiques seront expliquées donnant une idée des nouveaux " design " d'étude d'efficacité en conditions réelles d'utilisation.TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE3-BU Santé-Allées (315552109) / SudocSudocFranceF

Vieillissement et hydratation de la peau (aspect clinique, moléculaire et méthodes d'évaluation)

TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE3-BU Santé-Allées (315552109) / SudocSudocFranceF

PUVA (5-Methoxypsoralen Plus UVA) Enhances Melanogenesis and Modulates Expression of Melanogenic Proteins in Cultured Melanocytes

PUVA (combination of psoralens and ultraviolet A radiation) is a potent inducer of melanogenesis in normal human skin. The molecular mechanisms underlying this effect are poorly characterized. This study was undertaken to investigate the action of PUVA on melanogenesis in S91 murine melanoma cells and in cultured normal human melanocytes. Tyrosinase and DOPAchrome tautomerase (DCT) activities as well as melanin neosynthesis were measured in PUVA-treated pigment cells. To determine whether a correlation exists between PUVA-induced melanogenesis and expression of melanogenic enzymes, we analyzed the levels of tyrosinase, DCT, and tyrosinase-related protein-1 (TRP-1 or gp75) by western blotting in PUVA-treated cells. We demonstrate that UVA upregulates tyrosinase activity and melanin content with 5-methoxypsoralen at 1 μM. This phenomenon depends on the energy delivered during phototreatment. In both human and mouse cells, stimulation of melanogenesis correlated with an increase of the amount of tyrosinase. In PUVA-treated S91 cells, tyrosinase mRNA was increased, but no stimulation of DCT activity occurred in these cells, in agreement with the unchanged amount of DCT protein in cell extracts. On the contrary, in melanocytes treated with PUVA, a decrease in DCT protein was observed. Finally, the amount of TRP-1 protein was not affected by PUVA in either S91 cells or melanocytes.These results show that melanogenesis induced by PUVA is related to an increase in expression of tyrosinase. In melanocytes, melanogenesis and DCT are negatively correlated, which suggests that PUVA favors the metabolic pathway of dark-eumelanins with high UV-protective properties. This study also suggests that PUVA regulates tyrosinase, DCT, and TRP-1 expression in a noncoordinate manner

Dermatology today and tomorrow: from symptom control to targeted therapy

For many decades and until recently, medical approach to dermatologic diseases has been based on the physician’s ability to recognize and treat symptoms. Nowadays, advances in the understanding of the biology of diseases and in technologies for intervening against them have allowed physicians to diagnose and treat underlying disease pro- cesses rather than simply addressing the symptoms. This means that rather than addressing ‘the disease in humans’, physicians can now address the particular pathologic (biologic, molecular) disturbance as it presents in the individual patient, i.e., physicians now can practice something much closer to ‘personalized medicine’, leading to greater benefits for the patients and the health of society in general. The deeper understanding of ultraviolet radiation, the importance of photo- protection and increased knowledge about signalling pathways of melanoma and carcinoma have led to more complete care for the dermatologic patient. The current popularity for excessive exposure to the sun, without adequate application of the appropriate photoprotection remedies, is the origin of melanoma, but also for the weakening of the structure and func- tions of the skin. Indeed, fragility of the skin can affect humans around the world. In the senior population, this skin fragility is accompanied by pruritus, whereas atopic dermatitis is an inflammatory disease with highest prevalence in children and adolescents. Acne, the number one reason for dermatologic consultations worldwide, increases its prevalence in adoles- cents and in females. Senescent alopecia affects humans after menopause and andropause. The articles in this publication present an overview of the current advanced understanding of the diagnosis and therapeutic approaches in 6 fields of der- matology – dermatopaediatry and gerontodermatology, oncodermatology, hair loss, atopic dermatitis, photoprotection and acne – and thereby serve as a useful compendium of updated information and references for all healthcare professionals who see patients with presentations of the symptoms of these diseases