The primary aim of this study was to elucidate the role of the estrogen receptor (ER), a transcription factor involved in the nicotine- and 17β-estradiol (E2)-mediated up-regulation of α9-nAChR gene expression. A real-time polymerase chain reaction (PCR) assay was used to quantify the α9-nAChR mRNA expression levels of surgically isolated (n=339) and laser-capture microdissected tissues (ER+ versus ER-, n= 6 per group). Chromatin immunoprecipitation (ChIP) and luciferase-promoter activity assays were used to investigate the ER-mediated transcriptional regulation of α9-nAChR gene expression. We observed that breast tumors with higher α9-nAChR mRNA expression levels (i.e., a mean fold ratio in the tumor/normal-paired samples of greater than tenfold) were associated with the lowest 5-year disease-specific survival rate (50%, dead/alive= 4/4, total = 8 patients, P= 0.006), in contrast to breast tumors with low levels (i.e., a mean fold ratio of less than onefold) of α9-nAChR expression (88%, dead/alive= 3/22, total= 25 patients). Furthermore, higher α9-nAChR mRNA expression levels were preferentially detected in ER+ tumor tissues in comparison to ER- tumor tissues (ER+ versus ER- patients: n=160 vs. 72; mean fold ratios of α9-nAChR expression = 11 ± 3 vs. 6.7 ± 2.3 fold, respectively). In vitro promoter-binding assays demonstrated that the ER is a major transcription factor that mediates nicotine- and E2-induced up-regulation of α9-nAChR gene expression in MCF-7 cells. In conclusion, our data indicate that the ER plays a central role in mediating α9-nAChR gene up-regulation in response to either nicotine or E2 stimulation.

Objectives Dental problems occur widely in patients with chronic kidney disease (CKD) and may increase comorbidities. Root canal therapy (RCT) is a common procedure for advanced decayed caries with pulp inflammation and root canals. However, end-stage renal disease (ESRD) patients are considered to have a higher risk of potentially life-threatening infections after treatment and might fail to receive satisfactory dental care such as RCT. We investigated whether appropriate intervention for dental problems had a potential impact among dialysis patients. Design Men and women who began maintenance dialysis (hemodialysis or peritoneal dialysis) between January 1, 2000, and December 31, 2015, in Taiwan (total 12,454 patients) were enrolled in this study. Participants were followed up from the first reported dialysis date to the date of death or end of dialysis by December 31, 2015. Setting Data collection was conducted in Taiwan. Results A total of 2633 and 9821 patients were classified into the RCT and non-RCT groups, respectively. From the data of Taiwan’s National Health Insurance, a total of 5,092,734 teeth received RCT from 2000 to 2015. Then, a total of 12,454 patients were followed within the 16 years, and 4030 patients passed away. The results showed that members of the non-RCT group (34.93%) had a higher mortality rate than those of the RCT group (22.79%; p = 0.001). The multivariate-adjusted hazard ratio for the risk of death was 0.69 (RCT vs. non-RCT; p = 0.001). Conclusions This study suggested that patients who had received RCT had a relatively lower risk of death among dialysis patients. Infectious diseases had a significant role in mortality among dialysis patients with non-RCT. Appropriate interventions for dental problems may increase survival among dialysis patients. Abbreviations: CKD = chronic kidney disease, ESRD = end-stage renal disease, RCT = root canal therapy.

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