Sensitive skin is a subjective cutaneous hyper-reactivity that occurs in response to various innocuous stimuli. Keratinocytes have recently been shown to participate in sensory transduction by releasing many neuroactive molecules that bind to intra-epidermal free nerve endings and modulate nociception. In the literature, the characterization of these interactions has been based on the co-culture of keratinocyte and mammalian-origin neuronal cell lines. In this study, we established an in vitro model based on a co-culture of primary human keratinocytes and differentiated SH-SY5Y cells, a human neuronal cell line.
Injectable poly-l-lactic acid (PLLA) carries the risk of nodule or microlump formation. Various methods including sonication have been tried to minimize these adverse effects of PLLA.This study investigated the change in size, distribution, and properties of PLLA particles after sonication, and the duration of sonication needed to reach the ideal particle size.Two indicators, the average size of PLLA particles and diameter at 90%, were measured at each timepoint: at 0, 10, 60, 120, and 240 minutes of sonication. The characteristics and particle shape were assessed at 0 and 240 minutes.The average particle size and the diameter at 90% decreased drastically until 10 minutes of sonication and then increased slightly at 60 minutes. After 60 minutes, the average size and the diameter at 90% gradually decreased over time and reached 42.2 μm and 75.7 μm, respectively, at 120 minutes. After 240 minutes of sonication, the average particle size was 35.9 μm, much smaller than the smallest proper size required (40 μm). Standard deviation decreased gradually over time, which means that a more even distribution was obtained. Crystalline remnants were significantly less left with 120 minutes sonication compared to those with 120 minutes hydration only. PLLA particles were more cracked at the center, and microcrystals were more loosely distributed at the periphery after 120 minutes sonication.Sonication help reduce the average size of PLLA particles and achieve more even distribution. Therefore, we believe sonication may attribute to the safer use of PLLA.
Background. Radiofrequency treatment improves skin aging-related concerns by promoting collagen production. However, studies of the efficacy of multifrequency radiofrequency (MFRF) are lacking. Objectives. This study aimed to analyze the efficacy of MFRF for patients with aging skin. Methods. Three MFRF treatment sessions were performed for patients with concerns about skin aging. During these sessions, MFRF was applied to the face (but not the forehead). Pores, wrinkles, subjective satisfaction, and side effects were evaluated at the first visit and 4 weeks after the last treatment. Additionally, histological and immunohistochemical evaluations of collagen, elastic fibers, and STRO-1 were performed. Results. Wrinkles and the subjective satisfaction of patients were significantly improved ( and , respectively). However, there was no significant effect on the number of pores ( ). All side effects that occurred after treatment were tolerable and transient. Histological findings revealed thickening of collagen bundles and elastic fibers. Additionally, increases in collagen I, collagen III, and STRO-1 levels were observed using immunohistochemistry. Conclusions. MFRF treatment uses less energy than the existing radiofrequency equipment and can be an effective clinicopathologic modality for facial rejuvenation.
Common hyperkeratotic palmar skin lesions include chronic hand eczema (CHE), hyperkeratotic hand eczema (HHE), palmar psoriasis (PP). However, clinically differentiating these disorders is often challenging.
Polydeoxyribonucleotide (PDRN) is a mixture of deoxyribonucleotides. It serves as an anti‑inflammatory and tissue‑regenerating agent. The mitogen‑activated protein kinase pathway modulates cell growth and collagen accumulation. It also regulates inflammation by suppressing the expression of proinflammatory cytokines. In the present study, it was attempted to elucidate the molecular mechanism of PDRN in skin healing by confirming the effects of PDRN treatment on skin keratinocytes and fibroblasts, and by assessing the levels of collagen and inflammatory cytokines regulated by the extracellular signal‑regulated kinase (ERK) pathway. The potential effects of PDRN on skin regeneration were investigated. Fibroblast and keratinocyte proliferation and migration were analyzed using the water‑soluble tetrazolium‑8 and wound healing assays. The upregulation of collagen synthesis by PDRN‑induced ERK activation was analyzed in fibroblasts with or without an ERK inhibitor. Inflammatory cytokine expression levels in keratinocytes were determined using reverse transcription‑quantitative polymerase chain reaction. PDRN promoted the proliferation and migration of keratinocytes and fibroblasts. However, PDRN‑induced ERK phosphorylation differed between keratinocytes and fibroblasts; PDRN increased ERK phosphorylation and collagen accumulation in fibroblasts, while it inhibited matrix metalloproteinase expression. By contrast, PDRN inhibited ERK phosphorylation in keratinocytes, and it decreased inflammatory cytokine expression levels. PDRN affects skin cell proliferation and migration, and collagen and inflammatory cytokine expression levels via ERK signaling. Overall, PDRN exerts a positive effect on skin regeneration, but the mechanism by which it promotes skin regeneration varies among different skin cell types.
Benign lichenoid keratosis is one of the most common skin lesions that develop on the faces of middle-aged women. This study aimed to find an effective treatment method for benign lichenoid keratosis. A total of 49 patients, who had a positive diagnosis during 2010-2018, were enrolled in the study. An Investigator's Global Assessment of the lesion was done using the 5-point visual analog scale to evaluate treatment efficacy. After excluding subjects who did not have a follow-up photograph, 38 subjects were given an Investigator's Global Assessment score. Combination therapy using laser and a topical agent was useful in the management of benign lichenoid keratosis on the face. Ablative laser was effective for immediate improvement of the lesion, whereas non-ablative laser was also useful and showed several benefits over ablative laser. Optimal treatment should be decided after considering the patient's preference, compliance with treatment regimen, and skin type.
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