Celastrol, which targets IL-2/CD25 binding inhibition, induces T cell-mediated antitumor activity in melanoma

Interleukin-2 (IL-2) induces contrasting immune responses depending on its binding receptor subunit; thus, selective receptor binding is considered a key challenge in cancer therapeutic strategies. In this study, we aimed to investigate the inhibition of IL-2 action and antitumor activity of celastrol (CEL), a compound identified in a screen for IL-2/CD25 binding inhibitors, and to elucidate the underlying role of CEL in immune cells. We found that CEL selectively impairs the binding of IL-2 and CD25 and directly binds to IL-2 but not to CD25. CEL significantly suppressed the proliferation and signaling of IL-2-dependent murine T cells and interfered with IL-2-responsive STAT5 phosphorylation in IL-2 reporter cells and human PBMCs. After confirming the impact of CEL on IL-2, we evaluated its antitumor activity in C57BL/6 mice bearing B16F10 tumors and found that CEL significantly inhibited tumor growth by increasing CD8+ T cells. We also found that CEL did not inhibit tumor growth in T cell-deficient BALB/c nude mice, suggesting that its activity was mediated by the T-cell response. Moreover, combination therapy with low-dose CEL and a TNFR2 antagonist synergistically improved the therapeutic efficacy of the individual monotherapies by increasing the ratio of intratumoral CD8/Treg cells and suppressing Foxp3 expression. These findings suggest that CEL, which inhibits CD25 binding by targeting IL-2, exerts antitumor activity by mediating the T-cell response and could be a promising candidate for combination therapy in cancer immunotherapy against melanoma.

LncRNA SNHG4 Modulates EMT Signal and Antitumor Effects in Endometrial Cancer through Transcription Factor SP-1

Long non-coding RNAs (lncRNAs) are implicated in the initiation and progression of a variety of tumors, including endometrial cancer. However, the mechanisms of lncRNA in endometrial cancer formation and progression remain largely unknown. In this study, we confirmed that the lncRNA SNHG4 is upregulated in endometrial cancer and correlates with lower survival rates in endometrial cancer patients. Knock-down of SNHG4 significantly reduced cell proliferation, colonization, migration, and invasion in vitro, as well as modulating the cell cycle and reduced tumor growth of endometrial cancer in vivo. In addition, the effect of SNHG4 by the transcription factor SP-1 was confirmed in vitro. We found in this study that SNHG4/SP-1 plays an important role in endometrial cancer progression and may be used as a potential therapeutic and prognostic biomarker for endometrial cancer.

Butein Inhibits Cell Growth by Blocking the IL-6/IL-6Rα Interaction in Human Ovarian Cancer and by Regulation of the IL-6/STAT3/FoxO3a Pathway

Butea monosperma (Fabaceae) has been used in traditional Indian medicine to treat a variety of ailments, including abdominal tumors. We aimed to investigate the anti-IL-6 activity of butein in ovarian cancer and elucidate the underlying molecular mechanisms. Butein was isolated and identified from B. monosperma flowers, and the inhibition of IL-6 signaling was investigated using the HEK-Blue™ IL-6 cell line. The surface plasmon resonance assay was used to estimate the binding of butein to IL-6, IL-6Rα, and gp130. After treatment with butein, ovarian cancer cell migration, apoptosis, and tumor growth inhibition were evaluated in vitro and in vivo. Furthermore, we used STAT3 siRNA to identify the mechanistic effects of butein on the IL-6/STAT3/FoxO3a pathway. Butein suppressed downstream signal transduction through higher binding affinity to IL-6. In ovarian cancer, butein inhibited cell proliferation, migration, and invasion, and induced cell cycle arrest and apoptosis. In addition, it decreased the growth of ovarian cancer cells in xenograft tumor models. Butein inhibited STAT3 phosphorylation and induced FoxO3a accumulation in the nucleus by inhibiting IL-6 signaling. The anticancer activity of butein was mediated by blocking the IL-6/IL-6Rα interaction and suppressing IL-6 bioactivity via interfering with the IL-6/STAT3/FoxO3a pathway.

Inhibition of GP130/STAT3 and EMT by combined bazedoxifene and paclitaxel treatment in ovarian cancer

The interleukin 6 (IL-6)/glycoprotein 130 (GP130)/signal transducer and activator of transcription 3 (STAT3) signalling pathway, with GP130 as an intermediate membrane receptor, is involved in the survival, metastasis, and resistance of ovarian cancer. Bazedoxifene, an FDA-approved drug, is an inhibitor of GP130 and a selective estrogen modulator (SERM). We studied the mechanism of the combination therapy of bazedoxifene and paclitaxel in inhibiting the IL-6-mediated GP130/STAT3 signaling pathway in ovarian cancer. Surface plasmon resonance (SPR) was used to assess the binding of bazedoxifene to GP130. Migration, invasion, and apoptosis of ovarian cancer cells were assessed using bazedoxifene and paclitaxel. In addition, we determined the effects of bazedoxifene and paclitaxel alone or in combination on the GP130/STAT3 pathway and epithelial-mesenchymal transition (EMT). The results revealed that the combination of bazedoxifene and paclitaxel suppressed cell viability, migration, and invasion in the ovarian cancer cells. In addition, the combination treatment increased apoptosis. Furthermore, bazedoxifene combined with paclitaxel inhibited the growth of ovarian cancer cells in a xenograft tumour model. This combination reduced STAT3 phosphorylation and suppressed gene expression and EMT. In conclusion, inhibition of GP130/STAT3 signalling and EMT via a combination of bazedoxifene and paclitaxel could be used as a therapeutic strategy by which to overcome ovarian cancer.

Long Noncoding RNA E2F4as Promotes Progression and Predicts Patient Prognosis in Human Ovarian Cancer

Simple Summary

LncRNA is a promising biomarker that predicts the prognosis of a variety of cancers, but the important role of E2F4antisense lncRNA in cancer remains unclear. Therefore, we decided to explore the role of E2F4as lncRNA in the blood of an ovarian cancer patient. We found that E2F4as was highly expressed in ovarian cancer patients, and that the higher the expression of E2F4as, the worse the patient’s prognosis. In addition, we observed that downregulation of E2F4as in ovarian cancer cells reduced cell proliferation, invasion and migration, decreased expression of EMT-related genes, and increased apoptosis. These findings suggest that E2F4as may be a predictive biomarker in the blood of ovarian cancer patients, and have shown the potential to promote tumor aggression through EMT-related mechanisms.

Abstract

(1) Background: LncRNAs could be a promising biomarker to predict the prognosis of various cancers. The significance of E2F4antisense lncRNA remains unclear in cancer. In this study, we examined the expression level of E2F4as in the serum of ovarian cancer patients and the functional role of E2F4as. (2) Methods: Serum samples were obtained from 108 OC patients and 32 normal patients to measure the expression of E2F4as in the serum. Ovarian cancer cells were used to investigate the role of E2F4as in cell proliferation, invasion, migration and apoptosis, and the expression of E2F4as was knocked down using RNA interference. In addition, E2F4as knockdown cell lines were used in in vivo experiments. (3) Results: The expression of E2F4as was significantly higher in the serum of OC patients than in that of control patients (p < 0.05). The knockdown of E2F4as in ovarian cancer cells led to a decrease in cell proliferation, invasion and migration and an increase in apoptosis. E2F4as knockdown also reduced the expression of epithelium–mesenchymal metastasis (EMT) genes. (4) Conclusion: These findings highlight the clinical significance of E2F4as in predicting the prognosis of OC patients and suggest its potential in promoting tumour aggressiveness by the regulation of EMT-related mechanisms.

Glucagon-Like Peptide-1 Receptor Agonist Differentially Affects Brain Activation in Response to Visual Food Cues in Lean and Obese Individuals with Type 2 Diabetes Mellitus

BACKGROUND

To investigate the effects of a glucagon-like peptide-1 receptor agonist on functional brain activation in lean and obese individuals with type 2 diabetes mellitus (T2DM) in response to visual food cues.

METHODS

In a randomized, single-blinded, crossover study, 15 lean and 14 obese individuals with T2DM were administered lixisenatide or normal saline subcutaneously with a 1-week washout period. We evaluated brain activation in response to pictures of high-calorie food, low-calorie food, and nonfood using functional magnetic resonance imaging and measured appetite and caloric intake in participants who were given access to an ad libitum buffet.

RESULTS

Obese individuals with T2DM showed significantly greater activation of the hypothalamus, pineal gland, parietal cortex (high-calorie food vs. low-calorie food, P<0.05), orbitofrontal cortex (high-calorie food vs. nonfood, P<0.05), and visual cortex (food vs. nonfood, P<0.05) than lean individuals with T2DM. Lixisenatide injection significantly reduced the functional activation of the fusiform gyrus and lateral ventricle in obese individuals with T2DM compared with that in lean individuals with T2DM (nonfood vs. high-calorie food, P<0.05). In addition, in individuals who decreased their caloric intake after lixisenatide injection, there were significant interaction effects between group and treatment in the posterior cingulate, medial frontal cortex (high-calorie food vs. low-calorie food, P<0.05), hypothalamus, orbitofrontal cortex, and temporal lobe (food vs. nonfood, P<0.05).

CONCLUSION

Brain responses to visual food cues were different in lean and obese individuals with T2DM. In addition, acute administration of lixisenatide differentially affected functional brain activation in these individuals, especially in those who decreased their caloric intake after lixisenatide injection.

E2F8 regulates the proliferation and invasion through epithelial-mesenchymal transition in cervical cancer

The transcription factor E2F is an important modulator of the cell cycle, and the unrestricted activation of E2F-dependent transcription is considered to be an important driver of tumor formation and progression. E2F8 is known to play an important role in embryonic development and cell cycle control by inhibiting E2F1. However, it is not yet known whether E2F8 is involved in the progression of cervical cancer. In this study, the functional consequences of E2F8 knockdown in vitro and in vivo were explored. To demonstrate the function of E2F8 in cell proliferation, migration and invasion, we knocked down E2F8 in cervical cancer cell lines; in vitro and in vivo experiments using this knockdown showed that E2F8 potently induced the expression of epithelial-mesenchymal transition (EMT) markers. Finally, clinical data confirmed that E2F8 was a significant predictive factor for progression-free survival, and that patients with cervical cancer who exhibited high expression of E2F8 showed high FIGO stages and frequent recurrence rates compared to patients with low E2F8 expression. In conclusion, our study suggests that E2F8 is highly correlated with the progression-free survival of cervical cancer patients.

Long non-coding RNA steroid receptor activator promotes the progression of endometrial cancer via Wnt/ β-catenin signaling pathway

Rationale: Steroid receptor activator (SRA), a long non-coding RNA, serves as a critical regulator of gynecologic cancer. The objective of this study was to determine biological function and clinical significance of SRA expression in endometrial cancer.

Method: We investigated whether SRA was involved in the development of endometrial cancer via binding to eukaryotic translation initiation factor 4E-binding protein 1 (EIF4E-BP1) as a transcription factor to enhance Wnt/ β-catenin signaling pathway.

Results: Expression levels of SRA were upregulated in endometrial cancer tissues compared to those in adjacent control tissues. We also found high expression of SRA in EC cells. The relationship between SRA and EIF4E-BP1 was corroborated by transfection of a luciferase reporter plasmid. In addition, SRA knockdown inhibited the expression of EIF4E-BP1 known to play a critical role in the control of protein synthesis, cell growth, and cell survival, thus promoting tumourigenesis and epithelial-mesenchymal transition (EMT) important for cell motility and metastasis. Consistently, immunostaining and western blotting analysis showed that expression levels of β-catenin and 4EBP1 in the nucleus were significantly decreased by SRA knockdown but increased by SRA over-expression.

Conclusions: These results suggest that SRA is involved in proliferation, migration, and invasion of endometrial cancer cells by increasing the expression of EIF4E-BP1 and activity of Wnt/ β-catenin signaling. These findings indicate that SRA might be a novel biomarker for predicting recurrence and prognosis. It might also serve as a promising therapeutic target in endometrial cancer.

Components of Metabolic Syndrome in Korean Adults: A Hospital-Based Cohort at Seoul National University Bundang Hospital

Background

The prevalence of metabolic syndrome is increasing in Korea, particularly among young adults. This trend will increase the incidence of cardiovascular and metabolic diseases in the future. Therefore, it is imperative to detect and prevent metabolic abnormalities early in life. Here, we established a hospital-based biobank cohort to identify the most prevalent dysmetabolic phenotype. The aim of this report was to inform other researchers of our protocol and to share our data for future collaboration.

Methods

The baseline examination comprised health-related questionnaires, anthropometric and handgrip strength measurements, bioelectrical impedance analysis of body composition, and nutritional assessment. Relevant biochemical parameters were measured, and oral glucose tolerance tests were performed. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria with Asian waist circumference criteria.

Results

From a total of about 3,000 employees aged 20 to 59 years working at Seoul National University Bundang Hospital, 1,017 were enrolled from 2015 to 2016. The mean age was 34.5±8.4 years for men (n=311, 30.6%) and 30.9±8.5 years for women (n=706, 69.4%). The overall prevalence of metabolic syndrome was 7.6% (17.7% in men and 3.1% in women). Among the five components of metabolic syndrome, high blood pressure was the most prevalent in both men (51.4%) and women (13.8%).

Conclusion

Although further follow-up data are needed, we expect that more adverse cardiovascular events may occur in men than in women. This hospital-based cohort will serve as the foundation for a comprehensive evaluation of metabolic syndrome and future cardiometabolic disease risk in middle-aged Koreans.

Genetic Profiles Associated with Chemoresistance in Patient-Derived Xenograft Models of Ovarian Cancer

PURPOSE

Recurrence and chemoresistance (CR) are the leading causes of death in patients with high-grade serous carcinoma (HGSC) of the ovary. The aim of this study was to identify genetic changes associated with CR mechanisms using a patient-derived xenograft (PDX) mouse model and genetic sequencing.

MATERIALS AND METHODS

To generate a CR HGSC PDX tumor, mice bearing subcutaneously implanted HGSC PDX tumors were treated with paclitaxel and carboplatin. We compared gene expression and mutations between chemosensitive (CS) and CR PDX tumors with whole exome and RNA sequencing and selected candidate genes. Correlations between candidate gene expression and clinicopathological variables were explored using the Cancer Genome Atlas (TCGA) database and the Human Protein Atlas (THPA).

RESULTS

Three CR and four CS HGSC PDX tumor models were successfully established. RNA sequencing analysis of the PDX tumors revealed that 146 genes were significantly up-regulated and 54 genes down-regulated in the CR group compared with the CS group. Whole exome sequencing analysis showed 39 mutation sites were identified which only occurred in CR group. Differential expression of SAP25, HLA-DPA1, AKT3, and PIK3R5 genes and mutation of TMEM205 and POLR2A may have important functions in the progression of ovarian cancer chemoresistance. According to TCGA data analysis, patients with high HLA-DPA1 expression were more resistant to initial chemotherapy (p=0.030; odds ratio, 1.845).

CONCLUSION

We successfully established CR ovarian cancer PDX mouse models. PDX-based genetic profiling study could be used to select some candidate genes that could be targeted to overcome chemoresistance of ovarian cancer.

Postprandial glucose-lowering effect of premeal consumption of protein-enriched, dietary fiber-fortified bar in individuals with type 2 diabetes mellitus or normal glucose tolerance

AIMS/INTRODUCTION

Protein preload improves postprandial glycemia by stimulating secretion of insulin and incretin hormones. However, it requires a large dose of protein to produce a significant effect. The present study was carried out to investigate the postprandial glucose-lowering effect of a premeal protein-enriched, dietary fiber-fortified bar (PFB), which contains moderate amounts of protein, in individuals with type 2 diabetes mellitus or normal glucose tolerance (NGT).

MATERIALS AND METHODS

The participants (15 type 2 diabetes mellitus and 15 NGT) were randomly assigned to either a premeal or postmeal PFB group and underwent two mixed meal tolerance tests, 1 week apart in reverse order. Plasma levels of glucose, insulin, glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide were measured.

RESULTS

During the mixed meal tolerance tests, the incremental area under the curve from 0 to 180 min of plasma glucose levels was lower with premeal PFB than with postmeal PFB in the type 2 diabetes mellitus (14,723 ± 1,310 mg min/dL vs 19,642 ± 1,367 mg min/dL; P = 0.0002) and NGT participants (3,943 ± 416 mg min/dL vs 4,827 ± 520 mg min/dL, P = 0.0296). In the type 2 diabetes mellitus participants, insulinogenic index and the incremental area under the curve from 0 to 180 min of plasma total glucagon-like peptide-1 levels were higher with premeal PFB than with postmeal PFB, but not in the NGT participants. There was no difference in postprandial glucose-dependent insulinotropic polypeptide levels between premeal and postmeal PFB in both groups.

CONCLUSIONS

Acute administration of premeal PFB decreased postprandial glucose excursion in both type 2 diabetes mellitus and NGT participants. In the type 2 diabetes mellitus participants, premeal PFB augmented the early-phase insulin secretion, possibly through enhancing glucagon-like peptide-1 secretion.

In-hospital infective endocarditis following transcatheter aortic valve replacement: a cross-sectional study of the National Inpatient Sample database in the USA

BACKGROUND

While the utilization of transcatheter aortic valve replacement (TAVR) for patients with severe aortic stenosis has been increasing, in-hospital infective endocarditis (IE) following TAVR has not been well described.

AIM

To identify in-hospital IE following TAVR.

METHODS

All patients who underwent TAVR between 2012 and 2014 were identified using the National Inpatient Sample database. Multi-variate logistic regression was performed to identify the predictors of in-hospital IE after TAVR.

FINDINGS

Of the 41,025 patients who received TAVR, 120 patients (0.3%) developed in-hospital IE. Viridans group streptococci (20.8%) was the most frequent causative organism for in-hospital IE, followed by Staphylococcus aureus (16.7%) and enterococci (8.3%). Patients who developed in-hospital IE after TAVR had significantly higher rates of death (20.8% vs 4.1%, P<0.001), septic shock (16.7% vs 0.8%, P<0.001), cardiogenic shock (12.5% vs 3.4%, P=0.02), acute kidney injury requiring haemodialysis (16.7% vs 1.6%, P<0.001), bleeding requiring transfusion (29.2% vs 11.3%, P=0.01), myocardial infarction (12.5% vs 2.1%, P<0.001) and permanent pacemaker removal (4.2% vs 0.05%, P<0.001) compared with patients without IE. Independent predictors of in-hospital IE after TAVR include younger age [odds ratio (OR) 0.92, 95% confidence interval (CI) 0.89-0.95], drug abuse (OR 48.9, 95% CI 6.9-347.3) and human immunodeficiency virus (HIV) infection (OR 7.8, 95% CI 1.4-44.4).

CONCLUSION

IE occurred in 0.3% of patients after TAVR during the same hospitalization, resulting in higher rates of adverse outcomes including mortality. Patients with younger age, a history of drug abuse or HIV infection are at greater risk of in-hospital IE following TAVR, and would benefit from vigilant preventive measures perioperatively.

The long noncoding RNA HOXA11 antisense induces tumor progression and stemness maintenance in cervical cancer

Recent research has focused on the impact of long noncoding RNA (lncRNA) in cervical carcinogenesis. However, whether HOXA11 antisense (HOXA11-AS) is involved in cervical cancer remains to be elucidated. In the present study, we examined HOXA11-AS expression levels in cervical cancer patients and determined the relationships between HOXA11-AS expression and clinicopathological factors. We also investigated the bio-functional consequences of HOXA11-AS overexpression both in vitro and in vivo. HOXA11-AS expression was significantly greater in tissues from patients with cervical cancer than in control patients (P<0.001). Multivariate analysis showed that high HOXA11-AS was an independent prognosticator of overall survival (Hazard ratio=2.450, P=0.032). HOXA11-AS overexpression enhanced cell proliferation, migration, and tumor invasion in vitro, whereas HOXA11-AS knockdown inhibited these biologic aggressive features. These adverse changes were accompanied by characteristics of epithelial-mesenchymal transition (EMT). In vivo xenograft experiments using the siHOXA11-AS-transfected HeLa cells revealed that HOXA11-AS strongly induced tumor growth. Furthermore, we found that HOXA11-AS knockdown decreased cancer stemness and triggered the EMT program. In conclusion, HOXA11-AS overexpression correlated with poor survival in patients with cervical cancer. Thus, HOXA11-AS may be a pivotal target for exploring novel cervical cancer therapeutics.

Erratum: Correction of Figure. Clinical Implications of Various Criteria for the Biochemical Diagnosis of Insulinoma

This corrects the article on p. 498 in vol. 29, PMID: 25325272.

Long Non-coding RNA HOXA11 Antisense Promotes Cell Proliferation and Invasion and Predicts Patient Prognosis in Serous Ovarian Cancer

PURPOSE

The biological function of long non-coding RNAs (lncRNAs) is only partially understood; therefore, in this study, we investigated the expression of the novel HOXA11 antisense (HOXA11as) lncRNA and its oncogenic role in serous ovarian cancer (SOC).

MATERIALS AND METHODS

HOXA11as expression was examined in 129 SOC tissue samples by real time reverse transcription polymerase chain reaction. Clinicopathological factors and patient survival were compared between the high (n=27) and low HOXA11as expression group (n=102). To investigate the role of HOXA11as in cell proliferation, invasion, and migration, HOXA11as expression in ovarian cancer cells was knocked down using RNA interference.

RESULTS

HOXA11as expression in cancer tissue was 77-fold higher than that of noncancerous tissue (p < 0.05). Higher HOXA11as expression was significantly correlated with histological grade (p=0.017) and preoperative cancer antigen 125 (p=0.048). HOXA11as overexpression in SOC cells led to increased cell proliferation, invasion, and migration. Moreover, HOXA11as was associated with the expression of genes involved in cell invasion, migration, and epithelial-mesenchymal transition (EMT), including vascular endothelial growth factor, matrix metalloproteinase 9 (MMP-9), B-catenin, E-cadherin, Snail, Twist, and vimentin. Multivariate analysis revealed that HOXA11as was a prognostic factor of progressive disease and mortality (hazard ratio [HR], 1.730; p=0.043 and HR, 2.170; p=0.033, respectively). Progression-free and overall survival were significantly shorter in patients with high HOXA11as expression.

CONCLUSION

These findings highlight the clinical significance of HOXA11as to predicting the prognosis of SOC patients and suggest its potential in promoting tumor aggressiveness via regulation of vascular endothelial growth factor (VEGF), MMP-9, and EMT-related mechanisms.

Impact of metabolic syndrome on the progression of coronary calcium and of coronary artery disease assessed by repeated cardiac computed tomography scans

BACKGROUND

It is not clear how severe metabolic syndrome (MS) affects the development of coronary atherosclerosis.

METHODS

This was an observational, retrospective cohort study with Koreans who received health check-ups voluntarily. A total of 2426 subjects had baseline and follow-up coronary artery calcium score (CACS) data. Among them, 1079 had coronary computed tomography angiography (CCTA) data. We compared baseline CACS and any progression in subjects with and without MS. A more detailed analysis was conducted for coronary artery disease (CAD), which was defined by coronary artery stenosis (≥50 %), multivessel involvement, and coronary plaques in those patients with CCTA data.

RESULTS

At baseline, subjects with MS (34.0 %, n = 825) had higher CACS and more significant coronary artery stenosis, multivessel involvement, and atheromatous plaques than those without MS (P < 0.05 for all). In the follow-up (median 1197 days), subjects with MS showed significant increases in CACS and progression of CAD compared with counterparts without MS, in parallel with the numbers of MS components. Finally, MS was a significant predictor for the progression of CACS (hazard ratio 1.32; 95 % confidence interval 1.06-1.64) and progression of coronary artery stenosis and/or development of vulnerable plaque (hazard ratio 1.47, 95 % confidence interval 1.01-2.15) after adjusting for other cardiovascular risk factors.

CONCLUSIONS

Subjects with MS showed progression of CAD as assessed by CACS and CCTA over ~3 years. Therefore, more vigilant screening for coronary vascular health is needed among those with MS.

Serum bilirubin levels are positively associated with glycemic variability in women with type 2 diabetes

Aims/Introduction

Glycemic variability is known to induce oxidative stress. We investigated the relationships between glycemic variability and serum bilirubin levels, an endogenous anti‐oxidant, in patients with diabetes.

Materials and Methods

A cross‐sectional study was carried out with 77 patients with type 2 diabetes who had been recruited to two clinical studies from 2008 to 2014. There were no participants with diseases of the pancreas, liver, biliary tract and chronic renal insufficiency. Glycemic variation was calculated by a continuous glucose monitoring system, and correlation analyses were carried out to evaluate their association with bilirubin levels. Multiple linear regression was carried out to identify independent factors influencing bilirubin levels and glycemic variation.

Results

Among the participants, 42.3% were men. The mean (standard deviation) age was 61.5 years (10.4 years), body mass index was 24.2 kg/m² (2.8 kg/m²), diabetes duration was 17.7 years (9.5 years), hemoglobin A_1c was 60.7 mmol/mol (7.1 mmol/mol; 7.7 [0.7]%) and bilirubin was 11.8 μmol/L (4.10 μmol/L). Serum bilirubin levels were not different according to age, body mass index and hemoglobin A_1c. However, the mean amplitude of glucose excursion was positively associated with bilirubin levels in women (r = 0.588, P < 0.001). After adjustment with duration of diabetes, serum albumin, liver enzymes, and mean glucose, the correlation between bilirubin and mean amplitude of glucose excursion remained significant (r = 0.566, P < 0.001). Multiple linear regression analyses showed that bilirubin was an independent determinant for the mean amplitude of glucose excursion in women. 1,5‐Anhydroglucitol was also associated with bilirubin levels in women.

Conclusions

Bilirubin level within the physiological range might be an independent predictor for glycemic variability in women with type 2 diabetes.

Clinical implications of various criteria for the biochemical diagnosis of insulinoma

BACKGROUND

Among the various diagnostic criteria for insulinoma, the ratio criteria have been controversial. However, the amended insulin-glucose ratio exhibited excellent diagnostic performance in a recent retrospective cohort study, although it has not yet been validated in other patient cohorts. We examined the diagnostic performance of the current criteria of the Endocrine Society, insulin-glucose ratio, C-peptide-glucose ratio, and amended ratios in terms of differentiating insulinomas.

METHODS

We reviewed the medical records of patients who underwent evaluation for hypoglycemia from 2000 to 2013. Fourteen patients with histopathologically confirmed insulinoma and 18 patients without clinical evidence of insulinoma were included. The results of a prolonged fast test were analyzed according to the abovementioned criteria.

RESULTS

Fulfilling all three Endocrine Society criteria-plasma levels of glucose (<3.0 mmol/L), insulin (≥8 pmol/L), and C-peptide (≥0.2 nmol/L)-exhibited 100% sensitivity and 89% specificity. Fulfilling the glucose and C-peptide criteria showed 100% sensitivity and 83% specificity, while fulfilling the glucose and insulin criteria showed 100% sensitivity and 72% specificity. Among the ratio criteria, the insulin-glucose ratio [>24.0 (pmol/L)/(mmol/L)] gave the highest area under the receiver operating characteristic curve, with 93% sensitivity and 94% specificity.

CONCLUSION

Fulfilling the glucose, insulin, and C-peptide criteria of the Endocrine Society guidelines exhibited the best diagnostic performance for insulinoma. Nonetheless, the insulin-glucose ratio may still have a role in the biochemical diagnosis of insulinoma.

Innovations in drug-eluting stents

Coronary artery disease affects patients worldwide and is a major cause of morbidity and mortality. Historically, the treatment approach for patients with coronary syndromes has been surgical. In the 1970s, percutaneous balloon angioplasty was introduced, leading to creation of a new field of interventional cardiology, which allowed a non-surgical minimally invasive approach to treat patients with coronary artery disease. However, the major limitations of balloon angioplasty were acute vessel closure and later restenosis. The introduction of bare metal stents and then drug-eluting stents (DES) revolutionized the practice of interventional cardiology and allowed for safe treatment of increasingly complex coronary artery lesions. Although drug-eluting coronary stents improve patient outcomes, they still have limitations. These limitations may arise from delayed endothelialization, local vessel hypersensitivity and endothelial dysfunction secondary to the drug elution, the durable polymer coating, or the stent scaffold. This comprehensive review will discuss the evolution of intracoronary stents from their introduction to current utilization of DES as well as future research on bioabsorbable stents and polymers.

Reperfusion therapy in ST-elevation myocardial infarction: guidelines, strategies, pharmacology, and stent selection

Treatment of acute ST-elevation myocardial infarction (STEMI) has rapidly evolved with many advances made in the past decade. Percutaneous coronary intervention is the preferred strategy when available, although there remains a role for thrombolytic therapy, with prompt reperfusion as the primary goal. With regards to antithrombotic therapy, bivalirudin now has a significant role in STEMI care with improved outcomes over unfractionated heparin plus GP IIb/IIIa inhibitors. Dual antiplatelet therapy has become a mainstay of treatment with combination of aspirin and clopidogrel, as well as an expanding role of more potent novel agents, prasugrel and ticagrelor. In primary PCI in STEMI, coronary stents are now being used routinely, although short-term and long-term outcomes of drug-eluting stents (DES) versus bare metal stents (BMS) continue to be studied. Recent meta-analyses have examined the trade-off of lower rates of in-stent restenosis and need for target vessel revascularization with DES versus the potential increase in the risk of stent thrombosis and need for longer course of dual antiplatelet therapy. This review will discuss the current STEMI guidelines and strategies, recent advances in pharmacotherapy, and data on stent selection.

Methylation of the ribosyl moiety at position 34 of selenocysteine tRNA[Ser]Sec is governed by both primary and tertiary structure

The selenocysteine (Sec) tRNA[Ser]Sec population in higher vertebrates consists of two major isoacceptors that differ from each other by a single nucleoside modification in the wobble position of the anticodon (position 34). One isoacceptor contains 5-methylcarboxymethyluridine (mcmU) in this position, whereas the other contains 5-methylcarboxymethyluridine-2'-O-methylribose (mcmUm). The other modifications in these tRNAs are N6-isopentenyladenosine (i6A), pseudouridine (psi), and 1-methyladenosine (m1A) at positions 37, 55, and 58, respectively. As methylation of the ribose at position 34 is influenced by the intracellular selenium status and the presence of this methyl group dramatically alters tertiary structure, we investigated the effect of the modifications at other positions as well as tertiary structure on its formation. Mutations were introduced within a synthetic gene encoded in an expression vector, transcripts generated and microinjected into Xenopus oocytes, and the resulting tRNA products analyzed for the presence of modified bases. The results suggest that efficient methylation of mcmU to yield mcmUm requires the prior formation of each modified base and an intact tertiary structure, whereas formation of modified bases at other positions, including mcmU, is not as stringently connected to precise primary and tertiary structure. These results, along with the observations that methylation of mcmU is enhanced in the presence of selenium and that this methyl group affects tertiary structure, further suggest that the mcmUm isoacceptor must have a role in selenoprotein synthesis different from that of the mcmU isoacceptor.

Analysis of selenocysteine (Sec) tRNA([Ser]Sec) genes in Chinese hamsters

Several recent observations have indicated that the primary structure of the Chinese hamster selenocysteine tRNA([Ser]sec) is different than those of other mammalian species. These reports prompted us to investigate the gene sequence for this tRNA in Chinese hamsters. Southern blotting of Chinese hamster ovary (CHO) genomic DNA derived from cultured cells with a tRNA([Ser]sec) probe indicated several hybridizing bands, and each of the corresponding genetic loci was isolated from a recombinant CHO library by molecular cloning. Sequence analysis of these regions indicated three likely pseudogenes and a single functional gene whose sequence differed from those of other mammals. Of these, only one pseudogene and the putative functional gene are actively transcribed following their microinjection into Xenopus oocytes. The possibility that the functional CHO tRNA([Ser]sec) evolved from an edited transcript is discussed.

The zebrafish genome contains two distinct selenocysteine tRNA[Ser]sec genes

The zebrafish is widely used as a model system for studying mammalian developmental genetics and more recently, as a model system for carcinogenesis. Since there is mounting evidence that selenium can prevent cancer in mammals, including humans, we characterized the selenocysteine tRNA[Ser]sec gene and its product in zebrafish. Two genes for this tRNA were isolated and sequenced and were found to map at different loci within the zebrafish genome. The encoding sequences of both are identical and their flanking sequences are highly homologous for several hundred bases in both directions. The two genes likely arose from gene duplication which is a common phenomenon among many genes in this species. In addition, zebrafish tRNA[Ser]sec was isolated from the total tRNA population and shown to decode UGA in a ribosomal binding assay.