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Dihydrotestosterone (DHT) is the most potent androgen that regulates hair cycling. Hair cycling involves cross-talk between the androgen and Wnt/b-catenin pathways. However, how DHT regulates hair follicle (HF) growth through the Wnt/b-catenin pathway has not been well investigated. This study aimed to investigate the roles of DHT in hair growth in vivo and in vitro. Human scalp HFs were treated with different concentrations of DHT (10-5 , 10-6 , 10-7 , 10-8 , and 10-9 mol/L) for 10 days. The effects of DHT on hair shaft elongation, the proliferation of hair matrix cells, and the levels of b-catenin, GSK-3b, and phosphorylated GSK-3b (ser9) were evaluated in the cultured HFs. The effects of DHT were further investigated in C57BL/6 mice. Moreover, the growth of cultured human HFs was observed after interfering with the bcatenin pathway through inhibitors or activators in the presence or absence of DHT. We found that different concentrations of DHT had different effects on human HFs in vitro and C57BL/6 mice. At 10-6 mol/L, DHT inhibited HF growth and b-catenin/p-GSK-3b expression, whereas 10-7 mol/L DHT induced HF growth and b-catenin/p-GSK-3b expression. In addition, a bcatenin inhibitor (21H7) inhibited HF growth in vitro, while a b-catenin activator (IM12) promoted HF growth in vitro and antagonized the inhibition of HFs by high levels of DHT. These results suggest that DHT plays a pivotal role in region-specific hair growth, which may be related to the Wnt/b-catenin pathway.

Growth differentiation factor 11 (GDF11) is member of the transforming growth factor β (TGF-β) superfamily of proteins. Circulating GDF11 concentrations appear to decline with age, and its depletion is associated with cardiac hypertrophy and other morbidities. Knowledge of GDF11 regulation is limited, and the effects of natural genetic variation on GDF11 levels are currently undefined. We tested whether genetic background determines serum GDF11 concentrations using two classical inbred mouse strains: C57BL/6J (B6) and BALB/cByJ (BALB). B6 mice exhibited significantly higher GDF11 levels than BALB mice, and these strain differences were consistent throughout the life span. Overall, interactions between age and genetic background determined GDF11 concentrations, which were unaffected by sex. We then surveyed a panel of 22 genetically diverse inbred mouse strains and discovered a sixfold range in GDF11 levels at middle age. We estimated that 74.52% of phenotypic variation in GDF11 levels was attributable to genetic background. We used the Mouse Phenome Database to screen for phenotypes that correlate with GDF11. Interestingly, GDF11 levels predicted median strain life spans. This study revealed high heritability of GDF11 levels. Furthermore, our correlative data suggest that GDF11 may serve as a novel predictor of mammalian life span.

ObjectiveThis study aims to explore the necessity and safety of digestive endoscopy during the epidemic of coronavirus disease 2019.MethodsA retrospective cohort study method was used to collect patients’ data from the endoscopy center of the Civil Aviation General Hospital of China from February 1 to May 31, 2020, as the observation group. The patients’ data of endoscopic diagnosis and treatment during the same period in 2019 were used as a control group, to compare the differences in the number of diagnosis and treatment and the detection rate of gastrointestinal diseases in the two groups. At the same time, patients and related staff were followed up for the situation of new infection.ResultsDuring the epidemic, our endoscopy center conducted a total of 1,808 cases of endoscopic operations and 5,903 cases in the control group. The amount of endoscopic work during the epidemic period was 30.63% in the same period last year. During the epidemic, 26 patients underwent endoscopic mucosal resection (EMR)/endoscopic submucosal dissection (ESD) treatment, 26 patients underwent ERCP, and 18 patients underwent gastrointestinal stent implantation. In the control group, 273 patients underwent EMR/ESD, 17 underwent ERCP, and 16 underwent gastrointestinal stenting. During COVID-19, compared with the same period last year, the detection rates of peptic ulcer, esophageal cancer, gastric cancer, colon cancer, and rectal cancer were significantly higher (χ2 = 4.482, P = 0.034; χ2 = 5.223, P = 0.006; χ2 = 2.329, P = 0.041; χ2 = 8.755, P = 0.003; and χ2 = 5.136, P = 0.023). Through telephone follow-up, novel coronavirus nucleic acid detection and blood antibody detection, no patients or medical staff were infected with the novel coronavirus.ConclusionDuring COVID-19, the number of digestive endoscopic operations decreased significantly compared with the same period last year, but the detection rate of various diseases of the digestive tract increased significantly. On the basis of strict prevention and control, orderly recovery of endoscopic work is essential.