Background: Thyroid cancer is becoming increasingly common worldwide, but little is known about the epidemiology of medullary thyroid carcinoma (MTC). This study investigated the current status of the incidence and treatment of MTC using Korean National Health Insurance Service (NHIS) data for the entire Korean population from 2004 to 2016. Methods: This study included 1,790 MTC patients identified from the NHIS database. Results: The age-standardized incidence rate showed a slightly decreasing or stationary trend during the period, from 0.25 per 100,000 persons in 2004 to 0.19 in 2016. The average proportion of MTC among all thyroid cancers was 0.5%. For initial surgical treatment, 65.4% of patients underwent total thyroidectomy. After surgery, external-beam radiation therapy (EBRT) was performed in 10% of patients, a proportion that increased from 6.7% in 2004 to 11.0% in 2016. Reoperations were performed in 2.7% of patients (n=49) at a median of 1.9 years of follow-up (interquartile range, 1.2 to 3.4). Since November 2015, 25 (1.4%) patients with MTC were prescribed vandetanib by December 2016. Conclusion The incidence of MTC decreased slightly with time, and the proportion of patients who underwent total thyroidectomy was about 65%. EBRT, reoperation, and tyrosine kinase inhibitor therapy are additional treatments after initial surgery for advanced MTC in Korea.

BACKGROUND: Pheochromocytomas and paragangliomas (PPGLs) are rare endocrine tumors originating from chromaffin cells. PPGLs are associated with a high mortality rate and several complications. To date, no epidemiological studies have been conducted on PPGLs in Asia. This study aimed to investigate the epidemiology and prognosis of PPGLs in Korea using nationwide data. METHODS: Using the National Health Insurance Service Database, subjects with a principal diagnosis of PPGLs on two or more occasions between 2003 and 2014 who satisfied the operational definition of PPGLs were included. Incidence, prevalence, complications, metastasis, and mortality were investigated. RESULTS: In total, 1048 subjects with a mean age of 47.6±16.1 years were included. There was no sex preponderance. The overall prevalence of PPGLs was 2.13 per 100,000 persons, and the overall age-standardized incidence rate was 0.18 per 100,000 person-years. Malignant PPGLs accounted for 17.7% (185 of 1,048) of cases, and 94 subjects exhibited metastasis at the time of diagnosis. Among initially non-metastatic PPGLs, 9.5% (nine of 954) eventually metastasized after a mean duration of 78.1±41.4 months. The 5-year survival rates for non-metastatic and metastatic PPGLs at diagnosis were 97% and 84%, respectively. Multivariable Cox regression models adjusted for covariates showed that metastatic PPGLs were associated with a 2.40-fold higher risk of mortality than non-metastatic PPGLs (95% confidence interval, 1.38 to 4.17; P=0.002). CONCLUSION PPGLs are rare in Korea, and the prognosis of these endocrine tumors varies depending on whether they are benign or malignant. This epidemiological study paves the way for further research on PPGLs.

Anticancer effects of beta-lapachone (beta-lap) are due to generation of ROS and metabolic catastrophes as a result of NAD(P)H:quinone oxidoreductase (NQO1)-mediated futile cycling between the oxidized and reduced forms of beta-lap. It has been shown that NQO1 is also essential for the TNF-induced activation of NF-kappaB and that beta-lap suppresses the TNF-induced NF-kappaB activation. We investigated whether or not NQO1 is involved and beta-lap suppresses the radiation-induced NF-kappaB activation using A549 human lung cancer cells and NQO1-knock down A549 cells (shNQO1 A549 cells). Irradiation with 4 Gy markedly increased the DNA binding activity of NF-kappaB in A549 cells, but not in the shNQO1 A549 cells, thus demonstrating that NQO1 plays a pivotal role in irradiation-induced NF-kappaB activation. Treatment with 10 micrometer beta-lap for 4 h almost completely abrogated the radiation-induced increase in NF-kappaB activation and the transcription of NF-kappaB target genes such as bcl2, gadd45beta and cyclinD1. Moreover, beta-lap markedly suppressed the activation of IkappaB kinase gamma (IKKgamma) and the subsequent phosphorylation of IkappaBalpha, thereby inhibiting NF-kappaB activation. It is concluded that beta-lap suppresses the radiation-induced activation of NF-kappaB by interrupting the involvement of NQO1 in the activation of NF-kappaB, thereby inhibiting the transcription of survival signals. The radiosensitization caused by beta-lap may, in part, be attributed to beta-lap-induced suppression of NF-kappaB activation.

Background: Fibrosis is the most important prognostic factor for nonalcoholic fatty liver disease (NAFLD). Insulin resistance plays a key role of fibrosis progression. We evaluated the association between changes in homeostasis model assessment of insulin resistance (HOMA-IR) values and changes in fibrosis status in NAFLD. Methods: We analyzed the data of 15,728 participants with NAFLD (86% men, mean age 40.5 years) who had no diabetes at baseline and visited our centers for health check-ups both in 2012 and 2016. The participants were classified into four groups according to the degree of change in HOMA-IR values from baseline to the end of follow-up: G1 (<0), G2 (0–0.50), G3 (0.51–1.00), and G4 (>1.00). NAFLD was assessed by ultrasonography, and fibrosis status was evaluated by the NAFLD fibrosis score (NFS) and the aspartate aminotransferase to platelet ratio index (APRI). Results: After the 4-year follow-up, the multivariable-adjusted odds ratio (OR) for progression of fibrosis probability increased with increasing HOMA-IR values (OR, 2.25; 95% confidence interval [CI], 1.87 to 2.71 for NFS; and OR, 2.55; 95% CI, 2.05 to 3.18 for APRI, G4). This tendency remained consistent throughout the subgroup analyses, except in those for female sex and a body mass index <25 kg/m2. The OR for regression of fibrosis probability decreased with increasing HOMA-IR values (OR, 0.33; 95% CI, 0.25 to 0.43 for NFS, G4). Conclusion Changes in HOMA-IR values were associated with changes in fibrosis status in patients with NAFLD without diabetes, which underscores the role of insulin resistance in liver fibrosis.

Background: Weight loss through lifestyle modification is recommended for patients with nonalcoholic fatty liver disease (NAFLD). Recent studies have suggested that repeated loss and gain of weight is associated with worse health outcomes. This study aimed to examine the association between weight variability and the risk of NAFLD in patients without diabetes. Methods: We examined the health-checkup data of 30,708 participants who had undergone serial examinations between 2010 and 2014. Weight variability was assessed using coefficient of variation and the average successive variability of weight (ASVW), which was defined as the sum of absolute weight changes between successive years over the 5-year period divided by 4. The participants were classified according to the baseline body mass index and weight difference over 4 years. Results: On dividing the participants into four groups according to ASVW quartile groups, those in the highest quartile showed a significantly increased risk of NAFLD compared to those in the lowest quartile (odds ratio [OR], 1.89; 95% confidence interval [CI], 1.63 to 2.19). Among participants without obesity at baseline, individuals with high ASVW showed increased risk of NAFLD (OR, 1.80; 95% CI, 1.61 to 2.01). Participants with increased weight over 4 years and high ASVW demonstrated higher risk of NAFLD compared to those with stable weight and low ASVW (OR, 4.87; 95% CI, 4.29 to 5.53). Conclusion Regardless of participant baseline obesity status, high weight variability was associated with an increased risk of developing NAFLD. Our results suggest that further effort is required to minimize weight fluctuations after achieving a desirable body weight.

Background: Weight loss through lifestyle modification is recommended for patients with nonalcoholic fatty liver disease (NAFLD). Recent studies have suggested that repeated loss and gain of weight is associated with worse health outcomes. This study aimed to examine the association between weight variability and the risk of NAFLD in patients without diabetes. Methods: We examined the health-checkup data of 30,708 participants who had undergone serial examinations between 2010 and 2014. Weight variability was assessed using coefficient of variation and the average successive variability of weight (ASVW), which was defined as the sum of absolute weight changes between successive years over the 5-year period divided by 4. The participants were classified according to the baseline body mass index and weight difference over 4 years. Results: On dividing the participants into four groups according to ASVW quartile groups, those in the highest quartile showed a significantly increased risk of NAFLD compared to those in the lowest quartile (odds ratio [OR], 1.89; 95% confidence interval [CI], 1.63 to 2.19). Among participants without obesity at baseline, individuals with high ASVW showed increased risk of NAFLD (OR, 1.80; 95% CI, 1.61 to 2.01). Participants with increased weight over 4 years and high ASVW demonstrated higher risk of NAFLD compared to those with stable weight and low ASVW (OR, 4.87; 95% CI, 4.29 to 5.53). Conclusion Regardless of participant baseline obesity status, high weight variability was associated with an increased risk of developing NAFLD. Our results suggest that further effort is required to minimize weight fluctuations after achieving a desirable body weight.

Background: Dulaglutide, a long-acting glucagon-like peptide-1 receptor agonist (GLP-1RA), has been shown to reduce body weight and liver fat content in patients with type 2 diabetes. Family with sequence similarity 3 member A (FAM3A) plays a vital role in regulating glucose and lipid metabolism. The aim of this study was to determine the mechanisms by which dulaglutide protects against hepatic steatosis in HepG2 cells treated with palmitic acid (PA). Methods: HepG2 cells were pretreated with 400 μM PA for 24 hours, followed by treatment with or without 100 nM dulaglutide for 24 hours. Hepatic lipid accumulation was determined using Oil red O staining and triglyceride (TG) assay, and the expression of lipid metabolism-associated factor was analyzed using quantitative real time polymerase chain reaction and Western blotting. Results: Dulaglutide significantly decreased hepatic lipid accumulation and reduced the expression of genes associated with lipid droplet binding proteins, de novo lipogenesis, and TG synthesis in PA-treated HepG2 cells. Dulaglutide also increased the expression of proteins associated with lipolysis and fatty acid oxidation and FAM3A in PA-treated cells. However, exendin-(9-39), a GLP-1R antagonist, reversed the expression of FAM3A, and fatty acid oxidation-associated factors increased due to dulaglutide. In addition, inhibition of FAM3A by siRNA attenuated the reducing effect of dulaglutide on TG content and its increasing effect on regulation of fatty acid oxidation. Conclusion These results suggest that dulaglutide could be used therapeutically for improving nonalcoholic fatty liver disease, and its effect could be mediated in part via upregulation of FAM3A expression through a GLP-1R-dependent pathway.

Background: There is a great need to discover factors that could protect pancreatic β-cells from apoptosis and thus prevent diabetes mellitus. Clusterin (CLU), a chaperone protein, plays an important role in cell protection in numerous cells and is involved in various cellular mechanisms, including autophagy. In the present study, we investigated the protective role of CLU through autophagy regulation in pancreatic β-cells. Methods: To identify the protective role of CLU, mouse insulinoma 6 (MIN6) cells were incubated with CLU and/or free fatty acid (FFA) palmitate, and cellular apoptosis and autophagy were examined. Results: Treatment with CLU remarkably upregulated microtubule-associated protein 1-light chain 3 (LC3)-II conversion in a doseand time-dependent manner with a significant increase in the autophagy-related 3 (Atg3) gene expression level, which is a mediator of LC3-II conversion. Moreover, co-immunoprecipitation and fluorescence microscopy experiments showed that the molecular interaction of LC3 with Atg3 and p62 was markedly increased by CLU. Stimulation of LC3-II conversion by CLU persisted in lipotoxic conditions, and FFA-induced apoptosis and dysfunction were simultaneously improved by CLU treatment. Finally, inhibition of LC3-II conversion by Atg3 gene knockdown markedly attenuated the cytoprotective effect of CLU. Conclusion Taken together, these findings suggest that CLU protects pancreatic β-cells against lipotoxicity-induced apoptosis via autophagy stimulation mediated by facilitating LC3-II conversion. Thus, CLU has therapeutic effects on FFA-induced pancreatic β-cell dysfunction.

Background: Glucagon-like peptide-1 receptor agonist (GLP-1RA), which is a therapeutic agent for the treatment of type 2 diabetes mellitus, has a beneficial effect on the cardiovascular system. Methods: To examine the protective effects of GLP-1RAs on proliferation and migration of vascular smooth muscle cells (VSMCs), A-10 cells exposed to angiotensin II (Ang II) were treated with either exendin-4, liraglutide, or dulaglutide. To examine the effects of GLP-1RAs on vascular calcification, cells exposed to high concentration of inorganic phosphate (Pi) were treated with exendin-4, liraglutide, or dulaglutide. Results: Ang II increased proliferation and migration of VSMCs, gene expression levels of Ang II receptors AT1 and AT2, proliferation marker of proliferation Ki-67 (Mki-67), proliferating cell nuclear antigen (Pcna), and cyclin D1 (Ccnd1), and the protein expression levels of phospho-extracellular signal-regulated kinase (p-Erk), phospho-c-JUN N-terminal kinase (p-JNK), and phospho-phosphatidylinositol 3-kinase (p-Pi3k). Exendin-4, liraglutide, and dulaglutide significantly decreased the proliferation and migration of VSMCs, the gene expression levels of Pcna, and the protein expression levels of p-Erk and p-JNK in the Ang II-treated VSMCs. Erk inhibitor PD98059 and JNK inhibitor SP600125 decreased the protein expression levels of Pcna and Ccnd1 and proliferation of VSMCs. Inhibition of GLP-1R by siRNA reversed the reduction of the protein expression levels of p-Erk and p-JNK by exendin-4, liraglutide, and dulaglutide in the Ang II-treated VSMCs. Moreover, GLP-1 (9-36) amide also decreased the proliferation and migration of the Ang II-treated VSMCs. In addition, these GLP-1RAs decreased calcium deposition by inhibiting activating transcription factor 4 (Atf4) in Pi-treated VSMCs. Conclusion These data show that GLP-1RAs ameliorate aberrant proliferation and migration in VSMCs through both GLP-1Rdependent and independent pathways and inhibit Pi-induced vascular calcification.

Background: Glucagon-like peptide-1 receptor agonist (GLP-1RA), which is a therapeutic agent for the treatment of type 2 diabetes mellitus, has a beneficial effect on the cardiovascular system. Methods: To examine the protective effects of GLP-1RAs on proliferation and migration of vascular smooth muscle cells (VSMCs), A-10 cells exposed to angiotensin II (Ang II) were treated with either exendin-4, liraglutide, or dulaglutide. To examine the effects of GLP-1RAs on vascular calcification, cells exposed to high concentration of inorganic phosphate (Pi) were treated with exendin-4, liraglutide, or dulaglutide. Results: Ang II increased proliferation and migration of VSMCs, gene expression levels of Ang II receptors AT1 and AT2, proliferation marker of proliferation Ki-67 (Mki-67), proliferating cell nuclear antigen (Pcna), and cyclin D1 (Ccnd1), and the protein expression levels of phospho-extracellular signal-regulated kinase (p-Erk), phospho-c-JUN N-terminal kinase (p-JNK), and phospho-phosphatidylinositol 3-kinase (p-Pi3k). Exendin-4, liraglutide, and dulaglutide significantly decreased the proliferation and migration of VSMCs, the gene expression levels of Pcna, and the protein expression levels of p-Erk and p-JNK in the Ang II-treated VSMCs. Erk inhibitor PD98059 and JNK inhibitor SP600125 decreased the protein expression levels of Pcna and Ccnd1 and proliferation of VSMCs. Inhibition of GLP-1R by siRNA reversed the reduction of the protein expression levels of p-Erk and p-JNK by exendin-4, liraglutide, and dulaglutide in the Ang II-treated VSMCs. Moreover, GLP-1 (9-36) amide also decreased the proliferation and migration of the Ang II-treated VSMCs. In addition, these GLP-1RAs decreased calcium deposition by inhibiting activating transcription factor 4 (Atf4) in Pi-treated VSMCs. Conclusion These data show that GLP-1RAs ameliorate aberrant proliferation and migration in VSMCs through both GLP-1Rdependent and independent pathways and inhibit Pi-induced vascular calcification.