Skin aging is induced and sustained by chronological aging and photoaging. Aging skin pigmentation such as mottled pigmentation (senile lentigo) and melasma are typical signs of photoaging. The skin, like other human organs, undergoes cellular senescence, and senescent cells in the skin increase with age. The crosstalk between melanocytes as pigmentary cells and other adjacent types of aged skin cells such as senescent fibroblasts play a role in skin-aging pigmentation. In this review, we provide an overview of cellular senescence during the skin-aging process. The discussion also includes cellular senescence related to skin-aging pigmentation and the therapeutic potential of regulating the senescence process.

The human microbiome plays an important role in various diseases, including Behçet’s disease (BD). However, the effects of disease activity and covariates influencing the microbial composition have not yet been investigated. Therefore, we investigated the fecal and salivary microbiomes of BD patients compared to those of recurrent aphthous ulcer (RAU) patients, as well as dietary habit-matched healthy controls (HCs) selected from immediate family members using 16S rRNA gene sequencing. The fecal microbiome alpha diversity of BD patients was not different from that of their matched HCs, although it was higher than that of unrelated HCs and decreased in BD patients with disease activity. A tendency toward clustering in the beta diversity of the fecal microbiome was observed between the active BD patients and their matched HCs. Active BD patients had a significantly higher abundance of fecal Bacteroides uniformis than their matched HCs and patients with the disease in an inactive state (p = 0.038). The abundance of salivary Rothia mucilaginosa group was higher in BD patients than in RAUs patients. BD patients with uveitis had different abundances of various taxa, compared to those without uveitis. Our results showed an association of fecal microbiome composition with BD disease activity and symptoms, suggesting the possible role of the gut microbiome in BD pathogenesis.

Acral lentiginous melanoma (ALM) is a relatively rare clinicopathologic subtype of cutaneous malignant melanoma, but it is the most common type of melanoma among Asians. Although the research to identify immunohistochemical (IHC) markers to differentiate nevi from melanoma is being conducted, specific markers for ALM are not well-known. Therefore, we aimed to analyze and compare the differences in the expression of melanocyte-associated IHC markers between ALM and acral benign nevi (ABN). Two independent groups of 53 and 19 paraffin-embedded specimens (from patients with pathologically confirmed ALM and ABN, respectively) were subjected to IHC staining for MART-1, preferentially expressed antigen in melanoma (PRAME), SOX10, HMB-45, Ki-67, and p16. We performed a quantitative analysis of PRAME, SOX10, KI-67, and p16 expression and gradient pattern analysis of HMB-45 expression for each specimen. The PRAME (60.1% and 28.5%, P < 0.05) and Ki-67 (7.8% and 3.5%, P < 0.05) expression levels were significantly higher in the ALM group than in the ABN group. The p16 expression was significantly lower (14.2% and 19.4%, P < 0.05), and the absence of HMB-45 gradient was more frequent in the ALM group than in the ABN group. However, no statistical significance was noted in SOX10 (54.8% and 44.7%). Receiver operating characteristic curves showed that PRAME had the highest area under the curve value. In summary, among various IHC markers, PRAME was the most valuable marker for the diagnosis of ALM; however, further large-scale studies are needed to validate these findings.