BackgroundThere is no appropriate in vivo animal model that reflects the inflammatory response of human acne.ObjectiveThis study investigated the effect of Propionibacterium acnes on the development of inflammatory acne-like lesions in four mouse strains with different degrees of immune response for the development of an optimal mouse model of inflammatory acne.MethodsHuman P. acnes suspensions (108 and 109 colony forming unit [CFU]/µl) were injected into the backs of HR-1, BALB/c, vitamin D receptor-knockout (VDR k/o), and severe combined immunodeficiency disease mice. Inflammation levels were evaluated two weeks after injection of P. acnes suspensions. In addition, histopathological examination and immunohistochemical staining of the expressions of inflammatory biomarkers (i.e., CD4+/CD8+ T lymphocytes, neutrophils, myeloperoxidase, interleukin-1β, matrix metalloprotease (MMP)-2, MMP-3, MMP-9, toll-like receptor (TLR)-2, LL-37, and integrin α6) were performed on tissue specimens.ResultsThe HR-1 mouse strain exhibited the most remarkable inflammatory reaction with epithelial proliferation and microcomedone-like cyst formation. HR-1 mice also demonstrated aberrant integrin expression in the epidermis around both inflamed lesions and newly formed microcomedones. These findings were more prominent in the group receiving 109 CFU/µl P. acnes than 108 CFU/µl. MMP-9 expression in HR-1 mice was also upregulated around the microcomedone-like cysts. Finally, expression levels of TLR-2 and LL-37 were higher in HR-1 and BALB/c mice than the VDR k/o and SCID mice strains.ConclusionP. acnes induces acneiform inflammation with small microcomedones in HR-1 mice. Therefore, the HR-1 mouse strain represents a good candidate for the development of a new inflammatory acne mouse model.

Dear Editor: Dermatophytosis is common worldwide and is believed to affect more than 20%∼25% of the world's population 1 .The epidemiology of dermatophyte infection is influenced by the changing patterns of migration, growth in tourism, immunocompetence of the host, pathogenicity of the infectious agents, availability of medical treatment, and changes in socioeconomic conditions 2,3 . We investigated the epidemiology of fungal skin infections through a retrospective analysis of patient's medical records between 1979 and 2013. Of total 4,275,715 patients, 415,526 patients with clinically suspicious fungal infection were collected at Catholic Skin Clinic in Daegu. Most of the patients were enrolled from Daegu and Gyeongsangbuk-do province. Microscopic examination with 15% KOH preparation and culture using potato dextrose agar corn meal Tween 80 media were performed for fungal examination. Culture media maintained at 24 o C∼26 o C were examined after 2 to 4 weeks. Of 415,526 patients, 131,440 KOHand culture-proven patients were included in this study.

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BackgroundLaser/light-based devices may provide an alternative to conventional acne therapeutics in some patients with nonresponsive acne.ObjectiveWe investigated the efficacy of red or infrared light-emitting diode (LED) devices in a mouse model of Propionibacterium acnes-induced inflammation through clinical examination and histopathological and immunohistochemical studies.MethodsA human-derived Propionibacterium acnes suspension (109 colony-forming units /µl) was injected into the back of an HR-1 mouse. Then, a 28.9 J/cm2 650-nm red LED or 9.3 J/cm2 830-nm infrared LED was applied to the mouse with P. acnes-induced inflammation once daily for 2 weeks. Two weeks after treatment, histological findings with hematoxylin and eosin staining and expression levels of inflammatory biomarkers (integrin α6, neutrophils, interleukin [IL]-1β, and matrix metalloproteinase [MMP]-2/9) were evaluated in tissue specimens using immunohistochemical staining.ResultsMice treated with red and infrared LED showed clinical improvement in inflammatory nodules compared to mice in the control group. Red LED was much more effective than infrared LED. Epidermal hyperplasia, comedone-like cysts, and integrin α6 expression improved to a similar extent in the red and infrared LED treatment groups and control group. Neutrophil, IL-1β, MMP-2, and MMP-9 expression after treatment with red and infrared LED decreased considerably compared to expression in the control group.ConclusionIn a mouse model of P. acnes-induced inflammatory nodules, red and infrared LED devices may be an alternative to conventional acne therapies. In addition, a mouse model of P. acnes-induced inflammatory nodules is helpful for laboratory research of acne.

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