Acne: Inflammation
Section snippets
P. acnes and acne
acnes has been implicated in the pathogenesis of acne for more than 100 years. It was initially believed to be the direct cause of the disease when it was first isolated in 1896, and subsequent studies demonstrating an inflammatory response after injection of P. acnes into the skin reinforced this view.3, 4 However, these findings were cast into doubt when the organism was shown to reside on normal human skin 50 years later.5 The association between P. acnes and acne has been reaffirmed over
Development of inflammatory lesions: comedogenesis
Inflammatory lesions develop from comedones arising due to an abnormal pattern of keratinization in the sebaceous follicle.1 Comedogenesis was once thought to not be part of the inflammatory process, but detailed immunohistological studies that have followed the development of inflammatory acne lesions have shown this to be the first step toward formation of an inflammatory lesion. The microcomedone is now believed to be the earliest type of subclinical acne lesion.
Microcomedones develop into
Inflammation: Sequence of events
Debate over the initial cellular infiltrate in inflammatory acne lesions has continued since the first histological studies were carried out 30–40 years ago. Results of some of the first studies concluded that the lymphocyte was the initiating inflammatory cell type.20, 21, 22 However, Kligman's 1974 study10 concluded that there was an initial infiltrate of neutrophils followed by microscopic rupture of the sebaceous follicle wall and subsequent formation of a clinically visible inflamed
The role of p. acnes in inflammation
P. acnes has been shown to be associated with inflammatory acne through antibiotic resistance studies.6, 8 However, this bacterium has not been shown to be a direct cause of the disease or to be involved in the initiation of inflammation. Numbers of viable bacteria within follicles show no correlation with severity of inflammation, and some inflamed lesions do not contain viable P. acnes.29 However, nonviable P. acnes cells are immunostimulatory.30 P. acnes produces a number of enzymes and
Hypotheses and perspectives
The spontaneous resolution of acne is one of the most intriguing features of the disease, and any hypothesis concerning the pathogenesis of acne must attempt to provide an explanation for this event. There is now strong evidence that inflammation in acne is initiated by a specific CD4+ T-cell response. The lymphocytic infiltrate observed in early inflammatory lesions could be due to specific recruitment of T cells. Changes in the follicle microenvironment may lead to an increase in the
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Evaluation of in vitro anti-acne activities of Ocimum basilicum L. water extract
2022, Industrial Crops and ProductsAssociation of different cell types and inflammation in early acne vulgaris
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