Production of Superoxide Anions by Keratinocytes Initiates P. acnes-Induced Inflammation of the Skin

Acne vulgaris is a chronic inflammatory disorder of the sebaceous follicles. Propionibacterium acnes (P. acnes), a gram-positive anareobic bacterium, plays a critical role in the development of these inflammatory lesions. This study aimed at determining whether reactive oxygen species (ROS) are produced by keratinocytes upon P. acnes infection, dissecting the mechanism of this production, and investigating how this phenomenon integrates in the general inflammatory response induced by P. acnes. In our hands, ROS, and especially superoxide anions (O2•−), were rapidly produced by keratinocytes upon stimulation by P. acnes surface proteins. In P. acnes-stimulated keratinocytes, O2•− was produced by NAD(P)H oxidase through activation of the scavenger receptor CD36. O2•− was dismuted by superoxide dismutase to form hydrogen peroxide which was further detoxified into water by the GSH/GPx system. In addition, P. acnes-induced O2•− abrogated P. acnes growth and was involved in keratinocyte lysis through the combination of O2•− with nitric oxide to form peroxynitrites. Finally, retinoic acid derivates, the most efficient anti-acneic drugs, prevent O2•− production, IL-8 release and keratinocyte apoptosis, suggesting the relevance of this pathway in humans

EEMCO guidance for the assessment of hair shedding and alopecia.

Knowledge of the hair follicle anatomy and the dynamics of hair cycling is substantial. Recognizing the anagen, catagen and telogen phases as well as teloptosis and the hair eclipse phenomenon clearly characterizes the typical hair chronobiology. Physiological modulators include hormones, neuromediators, miscellaneous biomolecules, seasons, micro-inflammation and ageing. For individuals who present with the complaint of increased hair shedding or alopecia, a host of evaluation techniques are available in addition to history, physical examination and laboratory assessment. Various clinical hair techniques can help in assessing the efficacy of drugs and cosmetics on hair growth. The methods are quite similar to those used to establish a definite diagnosis in dermatological practice. Great strides have been made during the recent decades in the methodology of hair growth trials in dermatology and cosmetology. Clinical evaluations benefit from a few additional specific techniques that enhance the perception of hair (re-) growth, shedding and alopecia. These assessments include the determination of hair patterning and density that may be helped by the 'black-and-white felt' examination. Daily hair counts, the 'hair pull test' and the 'hair feathering test' are also available. Instrumental methods provide reliable quantitative information that is useful if there are adequate controls. Some photographic methods, the trichogram, hair weighing and variants of the hair growth window technique including the phototrichogram, videotrichogram and tractio-phototrichogram provide insight into the complexities of hair cycling and shedding. Skin biopsy is indicated for diagnostic purposes, especially when the hair loss is accompanied by scarring

Management of primary cicatricial alopecias: Options for treatment

Primary cicatricial alopecias (PCAs) are a poorly understood group of disorders that result in permanent hair loss. Clinically, they are characterized not only by permanent loss of hair shafts but also of visible follicular ostia along with other visible changes in skin surface morphology, while their histopathological hallmark usually (although not always) is the replacement of follicular structures with scar-like fibrous tissue. As hair follicle neogenesis in adult human scalp skin is not yet a readily available treatment option for patients with cicatricial alopecias, the aim of treatment, currently, remains to reduce symptoms and to slow or stop PCA progression, namely the scarring process. Early treatment is the key to minimizing the extent of permanent alopecia. However, inconsistent terminology, poorly defined clinical end-points and a lack of good quality clinical trials have long made management of these conditions very challenging. As one important step towards improving the management of this under-investigated and under-serviced group of dermatoses, the current review presents evidence-based guidance for treatment, with identification of the strength of evidence, and a brief overview of clinical features of each condition. Wherever only insufficient evidence-based advice on PCA management can be given at present, this is indicated so as to highlight important gaps in our clinical knowledge that call for concerted efforts to close these in the near future.</p