Glucocorticoid receptor-NECAB1 axis can negatively regulate insulin secretion in pancreatic β-cells

The mechanisms of impaired glucose-induced insulin secretion from the pancreatic β-cells in obesity have not yet been completely elucidated. Here, we aimed to assess the effects of adipocyte-derived factors on the functioning of pancreatic β-cells. We prepared a conditioned medium using 3T3-L1 cell culture supernatant collected at day eight (D8CM) and then exposed the rat pancreatic β-cell line, INS-1D. We found that D8CM suppressed insulin secretion in INS-1D cells due to reduced intracellular calcium levels. This was mediated by the induction of a negative regulator of insulin secretion-NECAB1. LC-MS/MS analysis results revealed that D8CM possessed steroid hormones (cortisol, corticosterone, and cortisone). INS-1D cell exposure to cortisol or corticosterone increased Necab1 mRNA expression and significantly reduced insulin secretion. The increased expression of Necab1 and reduced insulin secretion effects from exposure to these hormones were completely abolished by inhibition of the glucocorticoid receptor (GR). NECAB1 expression was also increased in the pancreatic islets of db/db mice. We demonstrated that the upregulation of NECAB1 was dependent on GR activation, and that binding of the GR to the upstream regions of Necab1 was essential for this effect. NECAB1 may play a novel role in the adipoinsular axis and could be potentially involved in the pathophysiology of obesity-related diabetes mellitus.

A new beta cell-specific mitophagy reporter mouse shows that metabolic stress leads to accumulation of dysfunctional mitochondria despite increased mitophagy

AIMS/HYPOTHESIS

Mitophagy, the selective autophagy of mitochondria, is essential for maintenance of mitochondrial function. Recent studies suggested that defective mitophagy in beta cells caused diabetes. However, because of technical difficulties, the development of a convenient and reliable method to evaluate mitophagy in beta cells in vivo is needed. The aim of this study was to establish beta cell-specific mitophagy reporter mice and elucidate the role of mitophagy in beta cell function under metabolically stressed conditions induced by a high-fat diet (HFD).

METHODS

Mitophagy was assessed using newly generated conditional mitochondrial matrix targeting mitophagy reporter (CMMR) mice, in which mitophagy can be visualised specifically in beta cells in vivo using a fluorescent probe sensitive to lysosomal pH and degradation. Metabolic stress was induced in mice by exposure to the HFD for 20 weeks. The accumulation of dysfunctional mitochondria was examined by staining for functional/total mitochondria and reactive oxygen species (ROS) using specific fluorescent dyes and antibodies. To investigate the molecular mechanism underlying mitophagy in beta cells, overexpression and knockdown experiments were performed. HFD-fed mice were examined to determine whether chronic insulin treatment for 6 weeks could ameliorate mitophagy, mitochondrial function and impaired insulin secretion.

RESULTS

Exposure to the HFD increased the number of enlarged (HFD-G) islets with markedly elevated mitophagy. Mechanistically, HFD feeding induced severe hypoxia in HFD-G islets, which upregulated mitophagy through the hypoxia-inducible factor 1-ɑ (Hif-1ɑ)/BCL2 interacting protein 3 (BNIP3) axis in beta cells. However, HFD-G islets unexpectedly showed the accumulation of dysfunctional mitochondria due to excessive ROS production, suggesting an insufficient capacity of mitophagy for the degradation of dysfunctional mitochondria. Chronic administration of insulin ameliorated hypoxia and reduced ROS production and dysfunctional mitochondria, leading to decreased mitophagy and restored insulin secretion.

CONCLUSIONS/INTERPRETATION

We demonstrated that CMMR mice enabled the evaluation of mitophagy in beta cells. Our results suggested that metabolic stress induced by the HFD caused the aberrant accumulation of dysfunctional mitochondria, which overwhelmed the mitophagic capacity and was associated with defective maintenance of mitochondrial function and impaired insulin secretion.

Quantification of DNA methylation for carcinogenic risk estimation in patients with non-alcoholic steatohepatitis

BACKGROUND

In recent years, non-alcoholic steatohepatitis (NASH) has become the main cause of hepatocellular carcinoma (HCC). As a means of improving the treatment of NASH-related HCCs based on early detection, this study investigated the feasibility of carcinogenic risk estimation in patients with NASH.

RESULTS

Normal liver tissue (NLT), non-cancerous liver tissue showing histological findings compatible with non-alcoholic fatty liver from patients without HCC (NAFL-O), non-cancerous liver tissue showing NASH from patients without HCC (NASH-O), non-cancerous liver tissue showing non-alcoholic fatty liver from patients with HCC (NAFL-W), non-cancerous liver tissue showing NASH from patients with HCC (NASH-W) and NASH-related HCC were analyzed. An initial cohort of 171 tissue samples and a validation cohort of 55 tissue samples were used. Genome-wide DNA methylation screening using the Infinium HumanMethylation450 BeadChip and DNA methylation quantification using high-performance liquid chromatography (HPLC) with a newly developed anion-exchange column were performed. Based on the Infinium assay, 4050 CpG sites showed alterations of DNA methylation in NASH-W samples relative to NLT samples. Such alterations at the precancerous NASH stage were inherited by or strengthened in HCC samples. Receiver operating characteristic curve analysis identified 415 CpG sites discriminating NASH-W from NLT samples with area under the curve values of more than 0.95. Among them, we focused on 21 CpG sites showing more than 85% specificity, even for discrimination of NASH-W from NASH-O samples. The DNA methylation status of these 21 CpG sites was able to predict the coincidence of HCC independently from histopathological findings such as ballooning and fibrosis stage. The methylation status of 5 candidate marker CpG sites was assessed using a HPLC-based system, and for 3 of them sufficient sensitivity and specificity were successfully validated in the validation cohort. By combining these 3 CpG sites including the ZC3H3 gene, NAFL-W and NASH-W samples from which HCCs had already arisen were confirmed to show carcinogenic risk with 95% sensitivity in the validation cohort.

CONCLUSIONS

After a further prospective validation study using a larger cohort, carcinogenic risk estimation in liver biopsy specimens of patients with NASH may become clinically applicable using this HPLC-based system for quantification of DNA methylation.

Abstract 5703: Quantification of DNA methylation for carcinogenic risk estimation in patients with non-alcoholic steatohepatitis

Background: In recent years, non-alcoholic steatohepatitis (NASH) has become the main cause of hepatocellular carcinoma (HCC). As a means of improving the treatment of NASH-related HCCs based on early detection, this study investigated the feasibility of carcinogenic risk estimation in patients with NASH.

Results: Normal liver tissue (NLT), non-cancerous liver tissue (N) showing histological findings compatible with non-alcoholic fatty liver (NAFL) from patients without HCC (NAFL-O), N showing NASH from patients without HCC (NASH-O), N showing NAFL from patients with HCC (NAFL-W), N showing NASH from patients with HCC (NASH-W) and NASH-related HCC (T) were analyzed. An initial cohort of 171 tissue samples and a validation cohort of 55 tissue samples (226 samples in total) were used. Genome-wide DNA methylation screening using the Infinium HumanMethylation450 BeadChip and DNA methylation quantification using high-performance liquid chromatography (HPLC) with a newly developed anion-exchange column were performed. Based on the Infinium assay, 4,050 CpG sites showed significant alterations of DNA methylation in 22 NASH-W samples relative to 36 NLT samples in the initial cohort, indicating that DNA methylation alterations had occurred in the NASH-W samples. On 3,234 of the 4,050 CpG sites, DNA methylation alterations in NASH-W samples relative to NLT samples were inherited by or strengthened in 22 T samples (Jonckheere-Terpstra trend test). Among the 3,234 CpG sites, receiver operating characteristic curve analysis identified 415 CpG sites discriminating NASH-W from NLT samples with area under the curve values of more than 0.95. Among the 415 CpG sites, we focused on 21 CpG sites showing more than 85% specificity, even for discrimination of NASH-W from 91 NASH-O samples. The DNA methylation status of these 21 CpG sites was able to predict the coincidence of HCC independently from histopathological findings such as ballooning and fibrosis stage (Brunt classification). The methylation status of 5 candidate marker CpG sites was assessed using a HPLC-based system, which will be easily introduced into clinical laboratories, and for 3 of them sufficient sensitivity and specificity was successfully validated in the validation cohort. By combining these 3 CpG sites including the ZC3H3 gene, of which expression alternation may affect the post-transcriptional regulation of various tumor-related genes, 10 NAFL-W and 11 NASH-W samples from which HCCs had already arisen were confirmed to show carcinogenic risk with 95% sensitivity in the validation cohort.

Conclusions: After a further prospective validation study using a larger cohort, carcinogenic risk estimation in liver biopsy specimens of patients with NASH may become clinically applicable using this HPLC-based system for quantification of DNA methylation.

Citation Format: Junko Kuramoto, Eri Arai, Mao Fujimoto, Ying Tian, Yuriko Yamada, Takuya Yotani, Satomi Makiuchi, Noboru Tsuda, Hidenori Ojima, Moto Fukai, Yosuke Seki, Kazunori Kasama, Nobuaki Funahashi, Haruhide Udagawa, Takao Nammo, Kazuki Yasuda, Akinobu Taketomi, Tatsuya Kanto, Yae Kanai. Quantification of DNA methylation for carcinogenic risk estimation in patients with non-alcoholic steatohepatitis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5703.

Characterization of the taste receptor-related G-protein, α-gustducin, in pancreatic β-cells

AIMS/INTRODUCTION

Taste receptors, T1rs and T2rs, and the taste-selective G-protein, α-gustducin, are expressed outside the taste-sensing system, such as enteroendocrine L cells. Here, we examined whether α-gustducin also affects nutrition sensing and insulin secretion by pancreatic β-cells.

MATERIALS AND METHODS

The expression of α-gustducin and taste receptors was evaluated in β-cell lines, and in rat and mouse islets either by quantitative polymerase chain reaction or fluorescence immunostaining. The effects of α-gustducin knockdown on insulin secretion and on cyclic adenosine monophosphate and intracellular Ca2+ levels in rat INS-1 cells were estimated. Sucralose (taste receptor agonist)-induced insulin secretion was investigated in INS-1 cells with α-gustducin suppression and in islets from mouse disease models.

RESULTS

The expression of Tas1r3 and α-gustducin was confirmed in β-cell lines and pancreatic islets. Basal levels of cyclic adenosine monophosphate, intracellular calcium and insulin secretion were significantly enhanced with α-gustducin knockdown in INS-1 cells. The expression of α-gustducin was decreased in high-fat diet-fed mice and in diabetic db/db mice. Sucralose-induced insulin secretion was not attenuated in INS-1 cells with α-gustducin knockdown or in mouse islets with decreased expression of α-gustducin.

CONCLUSIONS

α-Gustducin is involved in the regulation of cyclic adenosine monophosphate, intracellular calcium levels and insulin secretion in pancreatic β-cells in a manner independent of taste receptor signaling. α-Gustducin might play a novel role in β-cell physiology and the development of type 2 diabetes.

Randomized controlled trial on efficacy of oligomeric formula (HINE E-GEL®) versus polymeric formula (MEIN®) enteral nutrition after esophagectomy for esophageal cancer with gastric tube reconstruction

The efficacy of early enteral nutrition after esophageal cancer surgery has been reported. However, the choice of formula and management of diarrhea are important to achieve the goal of enhanced recovery after surgery. The aim of this study is to assess the frequency of diarrhea/completion rate of enteral nutrition regimen as primary endpoints and the postoperative nutritional status/body composition analysis/operative morbidity as secondary endpoints was compared between the two nutrition groups. Among the 122 patients who underwent esophagectomy for esophageal cancer between December 2015 and September 2017, 67 patients who met the eligibility criteria were randomly assigned to receive enteral nutrition with either HINE E-GEL® (HINE group; n = 33) or MEIN® (MEIN group; n = 34). The incidence of diarrhea was significantly lower in the HINE group (18.2 % vs. 64.7 %, P < 0.001). The score of Bristol scale of POD 6/7 was significantly lower in the HINE group (P = 0.019/P = 0.006, respectively). The completion rate of enteral nutrition regimen was significantly higher in the HINE group (97.4 % vs. 86.6 %, P = 0.002). The Controlling Nutritional Status scores and total protein levels at 6 months after surgery were significantly better in the HINE group (P = 0.030 and P = 0.023, respectively), indicating improved tendency in nutritional status in the HINE group. However, there were no significant differences in Prognostic Nutritional Index values, blood test results, rapid turnover proteins, body mass index, or body composition between the two groups. HINE E-GEL compared with MEIN may reduce the frequency of diarrhea, enabling patients to adhere to the scheduled enteral nutrition plan. Also, maintenance of nutritional status with HINE E-GEL was comparable or potentially better in some nutrition components to that with MEIN, indicating that HINE E-GEL can be an option for enteral nutrition following esophageal surgery to achieve the goal of successful completion of scheduled enteral nutrition and smooth transition to the normal diet.

Genome-wide profiling of histone H3K27 acetylation featured fatty acid signalling in pancreatic beta cells in diet-induced obesity in mice

AIMS/HYPOTHESIS

Epigenetic regulation of gene expression has been implicated in the pathogenesis of obesity and type 2 diabetes. However, detailed information, such as key transcription factors in pancreatic beta cells that mediate environmental effects, is not yet available.

METHODS

To analyse genome-wide cis-regulatory profiles and transcriptome of pancreatic islets derived from a diet-induced obesity (DIO) mouse model, we conducted chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) of histone H3 lysine 27 acetylation (histone H3K27ac) and high-throughput RNA sequencing. Transcription factor-binding motifs enriched in differential H3K27ac regions were examined by de novo motif analysis. For the predicted transcription factors, loss of function experiments were performed by transfecting specific siRNA in INS-1, a rat beta cell line, with and without palmitate treatment. Epigenomic and transcriptional changes of possible target genes were evaluated by ChIP and quantitative RT-PCR.

RESULTS

After long-term feeding with a high-fat diet, C57BL/6J mice were obese and mildly glucose intolerant. Among 39,350 islet cis-regulatory regions, 13,369 and 4610 elements showed increase and decrease in ChIP-Seq signals, respectively, significantly associated with global change in gene expression. Remarkably, increased H3K27ac showed a distinctive genomic localisation, mainly in the proximal-promoter regions, revealing enriched elements for nuclear respiratory factor 1 (NRF1), GA repeat binding protein α (GABPA) and myocyte enhancer factor 2A (MEF2A) by de novo motif analysis, whereas decreased H3K27ac was enriched for v-maf musculoaponeurotic fibrosarcoma oncogene family protein K (MAFK), a known negative regulator of beta cells. By siRNA-mediated knockdown of NRF1, GABPA or MEF2A we found that INS-1 cells exhibited downregulation of fatty acid β-oxidation genes in parallel with decrease in the associated H3K27ac. Furthermore, in line with the epigenome in DIO mice, palmitate treatment caused increase in H3K27ac and induction of β-oxidation genes; these responses were blunted when NRF1, GABPA or MEF2A were suppressed.

CONCLUSIONS/INTERPRETATION

These results suggest novel roles for DNA-binding proteins and fatty acid signalling in obesity-induced epigenomic regulation of beta cell function.

DATA AVAILABILITY

The next-generation sequencing data in the present study were deposited at ArrayExpress. RNA-Seq: Dataset name: ERR2538129 (Control), ERR2538130 (Diet-induced obesity) Repository name and number: E-MTAB-6718 - RNA-Seq of pancreatic islets derived from mice fed a long-term high-fat diet against chow-fed controls. ChIP-Seq: Dataset name: ERR2538131 (Control), ERR2538132 (Diet-induced obesity) Repository name and number: E-MTAB-6719 - H3K27ac ChIP-Seq of pancreatic islets derived from mice fed a long-term high-fat diet (HFD) against chow-fed controls.

A type 2 diabetes-associated SNP in KCNQ1 (rs163184) modulates the binding activity of the locus for Sp3 and Lsd1/Kdm1a, potentially affecting CDKN1C expression

Although genome-wide association studies have shown that potassium voltage-gated channel subfamily Q member 1 (KCNQ1) is one of the genes that is most significantly associated with type 2 diabetes mellitus (T2DM), functionally annotating disease-associated single nucleotide polymorphisms (SNPs) remains a challenge. Recently, our group described a novel strategy to identify proteins that bind to SNP-containing loci in an allele-specific manner. The present study successfully applied this strategy to investigate rs163184, a T2DM susceptibility SNP located in the intronic region of KCNQ1. Comparative analysis of DNA-binding proteins revealed that the binding activities for the genomic region containing SNP rs163184 differed between alleles for several proteins, including Sp3 and Lsd1/Kdm1a. Sp3 preferentially bound to the non-risk rs163184 allele and stimulated transcriptional activity in an artificial promoter containing this region. Lsd1/Kdm1a was identified to be preferentially recruited to the non-risk allele of the rs163184 region and reduced Sp3-dependent transcriptional activity in the artificial promoter. In addition, expression of the nearby cyclin‑dependent kinase inhibitor 1C (CDKN1C) gene was revealed to be upregulated after SP3 knockdown in cells that possessed non-risk alleles. This suggests that CDKN1C is potentially one of the functional targets of SNP rs163184, which modulates the binding activity of the locus for Sp3 and Lsd1/Kdm1a.

Characterization of hepatic lipid profiles in a mouse model with nonalcoholic steatohepatitis and subsequent fibrosis

Nonalcoholic steatohepatitis (NASH) is a major health problem since it often leads to hepatocellular carcinoma. However, the underlying mechanisms of NASH development and subsequent fibrosis have yet to be clarified. We compared comprehensive lipidomic profiles between mice with high fat diet (HFD)-induced steatosis and STAM mice with NASH and subsequent fibrosis. The STAM mouse is a model that demonstrates NASH progression resembling the disease in humans: STAM mice manifest NASH at 8 weeks, which progresses to fibrosis at 12 weeks, and finally develop hepatocellular carcinoma. Overall, 250 lipid molecules were detected in the liver using liquid chromatography-mass spectrometry. We found that STAM mice with NASH presented a significantly higher abundance of sphingolipids and lower levels of triacylglycerols than the HFD-fed control mice. The abundance of certain fatty acids in phospholipid side chains was also significantly different between STAM and control mice, although global levels of phosphatidylcholines and phosphatidylethanolamines were comparable. Finally, increase in levels of acylcarnitines and some diacylglycerols was observed in STAM mice toward the fibrosis stage, but not in age-matched control mice. Our study provides insights into the lipid status of the steatotic, NASH, and fibrotic liver that would help elucidate the molecular pathophysiology of NASH progression.

Demethylation of the MafB promoter in a compromised β-cell model

Recent studies suggest that dedifferentiation of pancreatic β-cells is involved in compromised β-cell function in diabetes mellitus. We have previously shown that the promoter activity of MafB, which is expressed in α-cells of adult islets and immature β-cells in embryonic pancreas but not in mature β-cells in mice, is increased in compromised β-cells of diabetic model mice. Here, we investigated a rat β-cell line of INS1 cells with late-passage numbers, which showed extremely low expression of MafA and insulin, as an in vitro model of compromised β-cells. In these INS1 cells, the mRNA expression and the promoter activity of MafB were upregulated compared with the early-passage ('conventional') INS1 cells. Analysis of the MafB promoter in these late-passage INS1 cells revealed that specific CpG sites in the MafB promoter were partially demethylated. The reporter assay revealed that the unmethylated promoter activity of the 373 bp region containing these CpG sites was higher than the in vitro methylated promoter activity. These results suggest that the chronic culture of the rat β-cell line resulted in partial DNA demethylation of the MafB promoter, which may have a role in MafB promoter activation and possible dedifferentiation in our compromised β-cell model.

Comparative analysis of type 2 diabetes-associated SNP alleles identifies allele-specific DNA-binding proteins for the KCNQ1 locus

Although recent genome-wide association studies (GWAS) have been extremely successful, it remains a big challenge to functionally annotate disease‑associated single nucleotide polymorphisms (SNPs), as the majority of these SNPs are located in non‑coding regions of the genome. In this study, we described a novel strategy for identifying the proteins that bind to the SNP‑containing locus in an allele‑specific manner and successfully applied this method to SNPs in the type 2 diabetes mellitus susceptibility gene, potassium voltage‑gated channel, KQT‑like subfamily Q, member 1 (KCNQ1). DNA fragments encompassing SNPs, and risk or non‑risk alleles were immobilized onto the novel nanobeads and DNA‑binding proteins were purified from the nuclear extracts of pancreatic β cells using these DNA‑immobilized nanobeads. Comparative analysis of the allele-specific DNA-binding proteins indicated that the affinities of several proteins for the examined SNPs differed between the alleles. Nuclear transcription factor Y (NF‑Y) specifically bound the non‑risk allele of the SNP rs2074196 region and stimulated the transcriptional activity of an artificial promoter containing SNP rs2074196 in an allele‑specific manner. These results suggest that SNP rs2074196 modulates the affinity of the locus for NF‑Y and possibly induces subsequent changes in gene expression. The findings of this study indicate that our comparative method using novel nanobeads is effective for the identification of allele‑specific DNA‑binding proteins, which may provide important clues for the functional impact of disease‑associated non‑coding SNPs.

Inhibition of Increases in Blood Glucose and Serum Neutral Fat byMomordica charantiaSaponin Fraction

Focusing on a functional component of Momordica charantia, saponin, we investigated its effects on serum glucose and neutral fat levels. Saponin was extracted as a butanol-soluble fraction (saponin fraction) from hot blast-dried Momordica charantia powder. The disaccharidase-inhibitory activity and the pancreatic lipase-inhibitory activity of the saponin fraction were measured, and in vivo sugar- and lipid-loading tests were performed. The saponin fraction inhibited disaccharidase activity and elevation of the blood glucose level after sucrose loading. The fraction also markedly inhibited pancreatic lipase activity and elevation of the serum neutral fat level after corn oil loading. Based on these findings, the main active component related to the anti-diabetic effect of Momordica charantia is present in the butanol fraction, and it may be saponin. The blood glucose and serum neutral fat-lowering effects of Momordica charantia were closely associated with its inhibitory activity against disaccharidase and pancreatic lipase.

Labor induction using modified metreurynters plus oxytocin at an institution in Japan: a retrospective study

OBJECTIVE

The authors evaluated the effectiveness and safety of "neo-metoro" or 'mini-metoro" metreurynters plus oxytocin for labor induction and assessed differences in parturition outcomes, according to the metreurynter used at induction initiation.

MATERIALS AND METHODS

The authors retrospectively reviewed 146 consecutive women with live singleton pregnancies, and who underwent induction. Parturition outcomes were vaginal delivery achieved within the planned schedule (VDPS), vaginal delivery finally achieved (VDF), and induction-to-delivery interval (IDI). Women were divided into neo-metoro, mini-metoro, and without metreurynter groups based on metreurynter use at induction initiation. The authors examined the relationships of metreurynter groups with factors, parturition outcomes, and adverse events. In 113 women who underwent two-day induction, the authors calculated IDI and adjusted odds ratio (AOR) for achieving delivery per unit time.

RESULTS

VDPS rates were 65% in nulliparous and 81% in multiparous women. VDF rates were 78% in nulliparous and 96% in multiparous women. AORs for VDPS were 0.30 in nulliparous women and 0.18 in Bishop score (BS) 1-3 class. AORs for VDF were 0.04 in BS1-3 class and 0.14 in BS4-5 class. In 113 women undergoing two-day induction, AORs for achieving delivery per unit time were 0.45 in nulliparous women, 0.46 in obese women, and 0.48 in BS1-3 class. Neo-metoro use at induction initiation tended to reduce IDI.

CONCLUSIONS

Labor induction using these metreurynters plus oxytocin is safe and effective. The advantages of neo-metoro over mini-metoro use at induction initiation remain unclear; neo-metoro use at induction initiation may reduce IDI.

Quantitative assessment of Pdx1 promoter activity in vivo using a secreted luciferase reporter system

The luciferase reporter system is useful for the assessment of various biological processes in vivo. The transcription factor pancreatic and duodenal homeobox 1 (Pdx1) is critical for the formation and the function of pancreatic β-cells. A novel reporter system using secreted Gaussia princeps luciferase (GLuc) under the control of a Pdx1 promoter was generated and activated in rat and mouse β-cell lines. This Pdx1-GLuc construct was used as a transgene for the generation of reporter mice to monitor Pdx1 promoter activity in vivo via the measurement of secreted GLuc activity in a small aliquot of blood. Significantly increased plasma GLuc activity was observed in Pdx1-GLuc mice. Analysis of Pdx1-GLuc mice by bioluminescence imaging, GLuc reporter assays using homogenates of various organs, and immunohistochemistry revealed that GLuc expression and activity were exponentially higher in pancreatic β-cells than in pancreatic non-β-cells, the duodenum, and other organs. In addition, GLuc activity secreted into the culture medium from islets isolated from Pdx1-GLuc mice correlated with the number of islets. The transplantation of Pdx1-GLuc islets into severe combined immunodeficiency mice elevated their plasma GLuc activity. Conversely, a partial pancreatectomy in Pdx1-GLuc mice reduced plasma GLuc activity. These results suggest that a secreted luciferase reporter system in vivo enables not only the monitoring of promoter activity but also a quantitative and minimally invasive assessment of physiological and pathological changes in small cell masses, such as pancreatic β-cells.

Development of double density whole brain fNIRS with EEG system for brain machine interface

Brain-machine interfaces (BMI) are expected as new man-machine interfaces. Non-invasive BMI have the potential to improve the quality of life of many disabled individuals with safer operation. The non-invasive BMI using the functional functional near-infrared spectroscopy (fNIRS) with the electroencephalogram (EEG) has potential applicability beyond the restoration of lost movement and rehabilitation in paraplegics and would enable normal individuals to have direct brain control of external devices in their daily lives. To shift stage of the non-invasive BMI from laboratory to clinical, the key factor is to develop high-accuracy signal decoding technology and highly restrictive of the measurement area. In this article, we present the development of a high-accuracy brain activity measurement system by combining fNIRS and EEG. The new fNIRS had high performances with high spatial resolution using double density technique and a large number of measurement channels to cover a whole human brain.

[Surgery for esophageal cancer complicate with cardiovascular disease]

A risk of cardiac complications is one of the most significant risks to patient undergoing major surgery. Especially, for the patients with cancer, the preoperative management can be complex. The direct effect of cancer and side effect of prior chemotherapy or radiation therapy should be considered. The 2007 American College of Cardiology/American Heart Association( ACC/AHA) guidelines on perioperative cardiovascular evaluation for noncardiac surgery concluded that 3 elements must be assessed to determine the risk of cardiac event. The preoperative risk in a patient is initially assessed by the presence or absence of clinical predictors of increased perioperative cardiovascular risk, the patient's level of cardiac function, and the underlying risk of the surgical procedure. Here we will provide an overview of issue that are relevant to patients with esophageal cancer.

Influence of preoperative chemotherapy for advanced thoracic oesophageal squamous cell carcinoma on perioperative complications

BACKGROUND

The Japan Clinical Oncology Group (JCOG) 9907 trial has changed the standard of care for advanced thoracic oesophageal cancer in Japan from postoperative chemotherapy to preoperative chemotherapy. The impact of preoperative chemotherapy on the risk of developing postoperative complications remains controversial. This article reports the safety analysis of JCOG9907, focusing on risk factors for postoperative complications.

METHODS

Patients with potentially resectable advanced thoracic oesophageal squamous cell carcinoma were randomized to either postoperative or preoperative chemotherapy followed by transthoracic oesophagectomy with D2-3 lymphadenectomy. Chemotherapy consisted of two cycles of cisplatin and 5-fluorouracil. Clinical baseline data, intraoperative complications, postoperative complications and in-hospital mortality, collected on the case report forms in a predetermined format, were analysed. Univariable and multivariable analyses were used to explore the risk of postoperative complications in relation to treatment group, age, sex, tumour depth, nodal metastasis, stage and location.

RESULTS

Of 330 patients randomized, 166 were assigned to receive postoperative chemotherapy and 164 preoperative chemotherapy; 162 and 154 patients respectively underwent surgery. The incidence of intraoperative complications, postoperative complications and in-hospital mortality was similarly low in both groups. Multivariable analysis showed that age, sex and tumour location were independently associated with an increase in postoperative complications, but preoperative chemotherapy was not.

CONCLUSION

Preoperative chemotherapy does not increase the risk of complications or hospital mortality after surgery for advanced thoracic oesophageal cancer.

Synthesis of a new [6]-gingerol analogue and its protective effect with respect to the development of metabolic syndrome in mice fed a high-fat diet

To determine the effects of a [6]-gingerol analogue (6G), a major chemical component of the ginger rhizome, and its stable analogue after digestion in simulated gastric fluid, aza-[6]-gingerol (A6G), on diet-induced body fat accumulation, we synthesized 6G and A6G. Mice were fed either a control regular rodent chow, a high-fat diet (HFD), or a HFD supplemented with 6G and A6G. Magnetic resonance imaging adiposity parameters of the 6G- and A6G-treated mice were compared with those of control mice. Supplementation with 6G and A6G significantly reduced body weight gain, fat accumulation, and circulating levels of insulin and leptin. The mRNA levels of sterol regulatory element-binding protein 1c (SREBP-1c) and acetyl-CoA carboxylase 1 in the liver were significantly lower in mice fed A6G than in HFD control mice. Our findings indicate that A6G, rather than 6G, enhances energy metabolism and reduces the extent of lipogenesis by downregulating SREBP-1c and its related molecules, which leads to the suppression of body fat accumulation.

Needle-free jet injection of small doses of Japanese encephalitis DNA and inactivated vaccine mixture induces neutralizing antibodies in miniature pigs and protects against fetal death and mummification in pregnant sows

Japanese encephalitis (JE) virus causes abortion and stillbirth in swine, and encephalitis in humans and horses. We have previously reported that immunogenicity of a DNA vaccine against JE was synergistically enhanced in mice by co-immunization with a commercial inactivated JE vaccine (JEVAX) under a needle-free injection system. Here, we found that this immunization strategy was also effective in miniature pigs. Because of the synergism, miniature pigs immunized twice with a mixture of 10 μg of DNA and a 1/100 dose of JEVAX developed a high neutralizing antibody titer (1:190 at 90% plaque reduction assay). Even using 1 μg of DNA, 3 of 4 pigs developed neutralizing antibodies. Following challenge, all miniature pigs with detectable neutralizing antibodies were protected against viremia. Pregnant sows inoculated with 10 or 1 μg of DNA mixed with JEVAX (1/100 dose) developed antibody titers of 1:40-1:320. Following challenge, fetal death and mummification were protected against in DNA/JEVAX-immunized sows.

Genetic analysis of interspecific incompatibility in Brassica rapa

In interspecific pollination of Brassica rapa stigmas with Brassica oleracea pollen grains, pollen tubes cannot penetrate stigma tissues. This trait, called interspecific incompatibility, is similar to self-incompatibility in pollen tube behaviors of rejected pollen grains. Since some B. rapa lines have no interspecific incompatibility, genetic analysis of interspecific incompatibility was performed using two F(2) populations. Analysis with an F(2) population between an interspecific-incompatible line and a self-compatible cultivar 'Yellow sarson' having non-functional alleles of S-locus genes and MLPK, the stigmas of which are compatible with B. oleracea pollen grains, revealed no involvement of the S locus and MLPK in the difference of their interspecific incompatibility phenotypes. In QTL analysis of the strength of interspecific incompatibility, three peaks of LOD scores were found, but their LOD scores were as high as the threshold value, and the variance explained by each QTL was small. QTL analysis using another F(2) population derived from selected parents having the highest and lowest levels of interspecific incompatibility revealed five QTLs with high LOD scores, which did not correspond to those found in the former population. The QTL having the highest LOD score was found in linkage group A02. The effect of this QTL on interspecific incompatibility was confirmed by analyzing backcrossed progeny. Based on synteny of this QTL region with Arabidopsis thaliana chromosome 5, a possible candidate gene, which might be involved in interspecific incompatibility, is discussed.

[Basic technique for reconstruction after esophagectomy]

The stomach as a conduit after esophagectomy is preferred to the colon because it is much simpler to prepare and involves only 1 anastomosis. The following principles should be followed in preparing the stomach as an esophageal substitute: the complete removal of lymphatics within the left gastric area, and careful preservation of the gastric intramural vascular network. The line of resection, where the vessels of the left gastric area enter the gastric wall, should be cautiously decided. Border between the left and right gastric area of the lesser curvature is identified by the courses of these arteries. The 1st GIA should be inserted slightly toward the caudal side, and the 2nd GIA should be fired along the resection-line. The final GIA should be advanced to the highest point. The space beneath the sternum in the anterior mediastinum is easily created with minimal blood loss. The space is initially created by blunt finger dissection through the abdominal and cervical incisions, and further developed by insertion of a flat malleable intestinal retractor with a hole on 1 side, which is useful for elevating the esophageal substitute without a twist.

[Which tube is better for esophagectomy?]

We performed differential lung ventilation for thoracoscopic esophagectomy. There are 2 tools available for differential lung ventilation: double lumen tube (DLT) and endbronchial blocker tube (blocker). We reviewed the best tube by studying esophageal cancer perioperative findings in thoracoscopic esophagectomy. We examined 85 esophagectomy cases from 2007, in which we used a blocker combined with a spiral tracheal tube or DLT. An average of 1.5 times displacement of the blocker occurred in blocker cases and resulted in ventilation inability requiring a surgical interruption. Because bronchial displacement was present, 2 cases had to block it in an intermediate bronchial trunk. In DLT cases, tube movement was not seen and we could maintain good ventilation. However, lymph node dissection (LND) was difficult in DLT cases and DLT required exchange via a spiral tube for cervical LND. Next, we compared 4 DLTs, and found that the phi con DLT tube was the best because of its pliability. We concluded that the best tube for esophagectomy is a phi con DLT because it allows easy control of the differential lung ventilation and this tube does not interfere with surgery.

Severity of residual stenosis of infarct-related lesion and left ventricular function after single-vessel anterior wall myocardial infarction: implication of ST-segment elevation in lead aVL of the admission electrocardiograms

BACKGROUND

The relationship between the severity of chronic-phase stenosis of infarct-related lesions (IRLs) and chronic left ventricular function in anterior acute myocardial infarctions (AMI) has not been adequately investigated.

HYPOTHESIS

This study investigated whether ST elevation in lead aVL of admission electrocardiogram (ECG) would be a determinant factor of the relationship between the severity of stenosis of the IRL and chronic left ventricular function after anterior wall AMI.

METHODS

One month after AMI, the IRL was evaluated by coronary angiography in 98 patients with anterior AMI, and left ventricular ejection fraction (LVEF) was determined using multigated radionuclide angiocardiography. Patients were classified according to the severity of the IRL: patients with 100% occlusion (Group O), patients with 90 to 99% stenosis (Group H), and patients with < or =75% stenosis (Group L). Patients with ST elevation > or =0.1 mV in the aVL lead on their admission ECG were included in the ST-elevation group, and those with ST elevation <0.1 mV were included in the non-ST-elevation group.

RESULTS

The LVEF was greater in the non-ST-elevation group than in the ST-elevation group (p<0.0001), and the LVEF in a whole group as follows: Group L LVEF>Group H LVEF>Group O LVEF (p = 0.0160). In the ST-elevation group, LVEF was higher in Group L than in the other groups (p = 0.0251). There were three independent predictors of a reduced LVEF: ST-elevation in aVL [odds ratio (OR): 3.38, p = 0.0044], IRL stenosis > or =90% (OR: 2.90, p = 0.0044), and the IRL occurring in the left anterior descending artery proximal to the first diagonal branch (OR: 6.31, p = 0.0024).

CONCLUSION

Left ventricular function was preserved, regardless of the severity of residual stenosis, in patients without ST elevation in aVL if the IRL was not totally occluded. In patients with ST elevation in aVL, LVEF was lower in patients with more severe stenosis, even if the IRL was patent.

Surgical repair of refractory strictures of esophagogastric anastomoses caused by leakage following esophagectomy

Refractory strictures of esophagogastric anastomosis caused by leakage following an esophagectomy are a severe complication, for which either repeated balloon dilations or bougies are not necessarily effective. In such a case, surgical repair is quite difficult because the esophageal substitute such as the stomach or colon is usually located in the mediastinum and severely adhesive to the neighboring organs. Furthermore, in case the resected stricture is too long for direct re-anastomosis to be performed, a free jejunal graft or a new esophageal substitute should be prepared. This paper proposes a procedure for the re-reconstruction of refractory stricture in the case of a retrosternal reconstruction with a gastric conduit, which frequently employs pull-up route. The anterior plate of the manubrium was divided medially from the notch to the symphysis with the sternal saw. The manubrium is then removed, bite by bite, like breaking up rocks, with a bone rongeur forceps, starting with the anterior plate, then the posterior plate, from upper median part to the lower and lateral part of the sternum until it reaches the symphysis and the sternoclavicular and the sternocostal joints. It is safer to destroy the manubrium little by little from the anterior side so that the posterior periosteum, which is likely to adhere tightly to the gastric conduit, can be preserved. After the manubrium is almost completely resected and the posterior periosteum of the manubrium is preserved, a median longitudinal incision is carefully made on the periosteum so as not to damage the gastric conduit that may be adhesive to the periosteum. The periosteum was gradually opened bilaterally separating the periostium and the gastric conduit. Although gastroenterological surgeons may hesitate to remove the manubrium, removing the manubrium and preserving the posterior periosteum make it possible to avoid injuring the gastric conduit and to provide a wide view around the stenosis for safely resecting the anastomotic stricture. Furthermore, this procedure allows direct re-anastomosis between the cervical esophagus and the gastric conduit without a complicated reconstruction such as a free jejunal graft. This procedure is strongly recommended as an alternative option so that a second reconstruction can be performed both safely and steadily.

Increase of serum cholesterol levels by heat-moisture-treated high-amylose cornstarch in rats fed a high-cholesterol diet

The effects of four cornstarches containing various contents of resistant starch on serum and liver cholesterol levels in rats fed a high-cholesterol diet were investigated. Male Sprague Dawley rats (aged 4 weeks) were divided into four groups (n = 7) and fed high-cholesterol diets containing 15% of cornstarch (CS), heat-moisture-treated CS (HCS), high-amylose CS (HA), or heat-moisture-treated HA (HHA) for 21 days. The results showed that the serum and hepatic level of total cholesterol, LDL-cholesterol, and triglyceride in rats of the HHA group and their arteriosclerosis index were significantly higher, suggesting that HHA increases the risk of arteriosclerosis under a high-cholesterol dietary condition. No significant between-group differences were noted in the levels of plasma mevalonic acid and hepatic HMG-CoA reductase mRNA, whereas fecal cholesterol excretion was significantly higher in the HHA group, indicating that the elevation of the serum and liver cholesterol levels was not due to the promotion of liver cholesterol synthesis and cholesterol absorption in the intestine.