BackgroundMicroneedle is a method that creates transdermal microchannels across the stratum corneum barrier layer of skin. No previous study showed a therapeutic effect of microneedle itself on hair growth by wounding.ObjectiveThe aim of this study is to investigate the effect of repeated microwound formed by microneedle on hair growth and hair growth-related genes in a murine model.MethodsA disk microneedle roller was applied to each group of mice five times a week for three weeks. First, to identify the optimal length and cycle, microneedles of lengths of 0.15 mm, 0.25 mm, 0.5 mm, and 1 mm and cycles of 3, 6, 10, and 13 cycles were applied. Second, the effect of hair growth and hair-growth-related genes such as Wnt3a, β-catenin, vascular endothelial growth factor (VEGF), and Wnt10b was observed using optimized microneedle. Outcomes were observed using visual inspection, real-time polymerase chain reaction, and immunohistochemistry.ResultsWe found that the optimal length and cycle of microneedle treatment on hair growth was 0.25 mm/10 cycles and 0.5 mm/10 cycles. Repeated microneedle stimulation promoted hair growth, and it also induced the enhanced expression of Wnt3a, β-catenin, VEGF, and Wnt10b.ConclusionOur study provides evidence that microneedle stimulation can induce hair growth via activation of the Wnt/β-catenin pathway and VEGF. Combined with the drug delivery effect, we believe that microneedle stimulation could lead to new approaches for alopecia.

There was no previous population-based study on the comparison of the risk of chronic spontaneous urticaria (CSU) between autoimmune thyroid diseases (AITD) and age- and gender-matched controls. The primary objective of this study was to evaluate the risk of CSU after diagnosis of AITD using national registry data from Korea. The secondary objective was to evaluate other risk factors of CSU. Based on the disease code diagnoses in 2003-2005, we composed an AITD group (n=3,659) and an age- and gender-matched control group (n=18,295). Each patient was tracked for whether CSU occurs or not until 2013. After adjusting for demographic differences and comorbidities, patients with AITD had a significantly higher rate of CSU compared to the control group (hazard ratio [HR], 1.46; 95% confidence interval [CI], 1.25-1.70; P<0.001). Among the AITD patients, the adjusted HR for CSU was higher in patients with Hashimoto's thyroiditis (HR, 1.50) than in those with Grave's disease (HR, 1.33), although the difference was not statistically significant (P=0.368). Analysis of CSU patients associated with AITD showed that female patients had a significantly higher risk of CSU compared to male ones (HR, 1.34; P=0.001) and that those with allergic rhinitis (HR, 1.51; P<0.001), atopic dermatitis (HR, 2.44; P<0.001), and asthma (HR, 1.50; P<0.001) had a significantly higher risk of CSU compared to patients without respective diseases. Our results demonstrated that AITD could be significantly associated with an increased risk of CSU.

Knowledge of the clinical course of chronic spontaneous urticaria (CSU) remains unclear. The purpose of our study was to investigate the clinical course of CSU in the Korean adult population. Each patient in the CSU group who was defined by disease codes between 2003 and 2007 was tracked whether he or she went into remission or not until 2013. Kaplan-Meier survival analysis was carried out to analyze remission, and log-rank tests were performed for between-group comparisons. Demographic differences between subjects who went into remission 1 year after the initial diagnosis and those who did not were analyzed using χ2 tests. A total of 13,969 subjects were included in the CSU group. The 1-, 2-, 3-, 4-, and 5-year remission rates of CSU were 21.5%, 33.0%, 38.9%, 42.6%, and 44.6%, respectively. The proportion of subjects in the 65+ age group (P=0.050) and with male gender (P=0.002) was significantly higher among subjects who did not go into remission 1 year after the initial diagnosis. Our study indicates that CSU could have a more persistent course than previously reported.

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