Insulin secretion by the pancreatic β-cells is elicited in response to elevated extracellular glucose concentration. In addition to triggering insulin secretion, glucose-induced signal regulates β-cell proliferation and survival. However, the molecular mechanism underlying the effects of glucose on the β-cell functionality still remains unclear. Glucokinase, a hexokinase isozyme that catalyzes the phosphorylation of glucose, acts as the glucose sensor in the β-cells. To investigate the mechanisms of glucose signaling in the regulation of β-cell functions, we analyzed the role of glucokinase in insulin secretion, β-cell proliferation and β-cell apoptosis, using β-cell-specific glucokinase-haploinsufficient (Gck+/–) mice and allosteric glucokinase activators (GKAs). Glucokinase-mediated glucose metabolism (1) suppresses endoplasmic reticulum (ER) stress-induced β-cell apoptosis via inducing insulin receptor substrate-2 (IRS-2) expression and expression of ER stress-related molecules, (2) promotes adaptive β-cell proliferation through activation of the Forkhead Box M1 (FoxM1)/polo-like kinase-1 (PLK1)/centromere protein-A (CENP-A) pathway, (3) induces islet inflammation by promoting interaction of islet-derived S100 calcium-binding protein A8 (S100A8) with macrophages, (4) induces the expression of Fibulin-5 (Fbln5), an extracellular matrix protein to regulate β-cell functions, and (5) activates other unknown pathways. Glucagon-like peptide-1 (GLP-1) receptor agonists and dipeptidyl peptidase 4 (DPP-4) inhibitors have been found to possibly compensate for dysregulation of glucose metabolism in the β-cells. This review provides an update and overview of the recent advances in the study of β-cell pathophysiology and some therapeutic possibilities focusing on glucose-/glucokinase-mediated signaling.
Visceral adipose tissue-derived serine protease inhibitor (vaspin), initially identified in the visceral adipose tissue, is an adipokine that improves endoplasmic reticulum stress in obesity or insulin sensitivity and glucose tolerance. However, the transcriptional regulation of the hepatic vaspin gene remains elusive. We have previously shown that CCAAT-enhancer-binding protein α, a transcription factor of the basic leucine zipper class, positively regulates the vaspin gene. The present study aimed to investigate the nutritional or hormonal regulators of vaspin expression in the liver. For the fasting and refeeding study, mice in the fasting group were subjected to fasting for 24 h and then sacrificed. Mice in the refeeding group were subjected to fasting for 24 h and then refed with a 50% (w/w) sucrose/MF diet for further 24 h and then sacrificed. For the streptozotocin (STZ) study, STZ (50 mg/kg) was intraperitoneally injected into C57BL/6JJc1 mice for 5 d. Hepatic vaspin was repressed due to fasting for 24 h and was induced upon refeeding with a high-sucrose diet. In studies on liver-specific C/EBPα-deficient mice, C/EBPα was not involved in the induction of hepatic vaspin upon refeeding. In addition, the depletion of insulin by streptozotocin treatment markedly decreased hepatic vaspin expression. Finally, fasting-repressed vaspin expression in the liver was significantly increased by direct injection of insulin into fasting mice. In conclusion, our results suggest that insulin is a positive regulator of hepatic vaspin expression.
To estimate pregnancy complications in women newly diagnosed with gestational diabetes mellitus (GDM) according to the new International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria and verify the validity of introducing the IADPSG criteria in Japan. This retrospective study included data from women with singleton delivery at 22 weeks or later at a tertiary hospital during 2000–2009. We compared pregnancy outcomes between women who would now be diagnosed with GDM according to the IADPSG criteria but not by the old JSOG criteria (IGT group, n = 503) and women with normal glucose tolerance according to both the criteria (NGT group, n = 2,789). Multivariate analysis was performed and adjusted for background factors. Maternal age at delivery and pre-pregnancy BMI were significantly higher in the IGT group than in the NGT group, while gestational weeks at delivery did not differ between the groups. No difference was observed in the rates of GDM-related composite complications (defined as cases with at least one of the following: macrosomia, shoulder dystocia, neonatal hypoglycemia, neonatal hyperbilirubinemia, or neonatal respiratory distress syndrome) at 11.9% and 8.8% (adjusted odds ratio (OR) 1.30, 95% confidence interval (CI) 0.90–1.87, p = 0.16). Pregnancy outcomes did not differ significantly between the IGT and NGT groups, except for frequencies of total neonatal admissions at 10.5% and 7.1%, respectively (adjusted OR 1.55, 95% CI 1.12–2.13, p < 0.01).
Glucocorticoids play a critical role in the regulation of homeostasis, including metabolism. In patients with Cushing’s syndrome, chronic glucocorticoid excess disrupts physiological internal milieu, resulting in central obesity, muscle atrophy, fatty liver, and insulin resistance. However, the relationship among various metabolic effects of glucocorticoids remains unknown. In the present study, we studied a male mouse model of Cushing’s syndrome and indicated that glucocorticoid excess alters metabolic phenotype and body composition involving possible communication among skeletal muscle, liver, and adipose tissue.
We report a case of a 47-year-old woman with hypercalcemia 6 months after discontinuation of denosumab. She underwent right mastectomy for breast cancer and had received aromatase inhibitor and denosumab therapy for 5 years. Thirst, appetite loss, and bilateral ankle pain began few months after cessation of denosumab. She was admitted to the hospital for hypercalcemia and hyperthyroidism 6 months after the last dose of denosumab. Laboratory investigations revealed hypercalcemia, normophosphatemia, normal renal function, and elevated levels of fibroblast growth factor 23 (FGF-23). Serum tartrate-resistant acid phosphatase 5b and urine N-terminal cross-linked telopeptide of type I collagen were both elevated, and bone scintigraphy revealed increase of whole bone uptake. Radiological examinations showed no recurrence of breast cancer or tumors that secrete intact PTH or FGF-23. Hypercalcemia, which lasted for 1 month, was refractory to discontinuation of the aromatase inhibitor, normalization of thyroid hormone levels, saline hydration, and calcitonin administration, but was effectively treated with zoledronic acid. Abnormal uptake on bone scintigraphy and ankle pain both resolved a few months after treatment, and hypercalcemia has not recurred in the ensuing 2 years. In conclusion, we found elevated levels of circulating FGF-23 with hypercalcemia following the discontinuation of denosumab. FGF-23 might be a surrogate marker for massive bone resorption triggered by discontinuation of long-term denosumab treatment.
The fat-specific protein 27 gene (Fsp27) belongs to the cell death-inducing DNA fragmentation factor 45-like effector family. Fsp27 is highly expressed in adipose tissue and fatty liver. In adipocytes, FSP27 localizes to the membrane of lipid droplets and promotes lipid droplet hypertrophy. Recently, FSP27 was shown to consist of two isoforms, FSP27α and FSP27β. Previously, we demonstrated that Fsp27a is directly regulated by peroxisome proliferator-activated receptor γ (PPARγ) in fatty livers of genetically obese leptin deficient ob/ob mice and that Fsp27b may potentially be regulated by different factors transcriptionally as they both have a different promoter region. Thus, the aim of the present study was to elucidate whether Fsp27b is regulated by PPARγ in fatty liver. Fsp27a and Fsp27b were markedly induced in fatty liver of ob/ob mice compared with those in the normal liver. However, both Fsp27a/b were expressed at markedly lower levels in liver-specific PPARγ knockout mice with an ob/ob background. Further, the PPAR response element (PPRE) for the PPARγ-dependent promotion of Fsp27b promotor activity was revealed at position –1,163/–1,151 from the transcriptional start site (+1). Interestingly, the cis-element responsible for the PPARγ-dependent induction of Fsp27b was the same as that responsible for PPARγ-dependent induction of Fsp27a. These results suggest that PPARγ regulates not only Fsp27a but also Fsp27b in fatty liver of ob/ob mice through a common PPRE.
Available data is insufficient to identify the influence of visceral adiposity assessed by visceral adiposity index (VAI) on incident MetS. This study was to evaluate the association of VAI with incident MetS. In a cohort of Korean genome epidemiology study, 5,807 free of MetS were followed-up for 10 years. They were subdivided into 3 tertile groups according to VAI score. Cox proportional hazard model was used to evaluate the hazard ratios (HRs) and 95% confidential interval (CI) [adjusted HRs (95% CI)] for MetS according to VAI tertiles. Subgroup analyses were conducted for VAI and waist circumference (WC). Receiver operating characteristic (ROC) and area under curve (AUC) analyses were conducted to compare the discriminative ability for Mets among indices. The risk for MetS increased proportionally to VAI tertiles in all participants, which was similarly observed in both men and women. Subgroup analysis indicated that group with high VAI and low WC had the increased risk for MetS (all participants: 2.76 [2.48–3.07], men: 2.77 [2.40–3.19] and women: 2.55 [2.16–3.00]), compared with groups with low VAI and low WC. Group with low VAI and high WC generally had the higher adjusted HRs for MetS than group with the high VAI and low WC. In AUC analyses, WC had the highest discriminative ability for Mets. In conclusion, elevated VAI was significantly associated with the increased long-term risk of MetS. VAI is a useful supplementary to classic anthropometric indices in screening high risk group of MetS.
Fatigue is a common symptom in patients visiting the clinic of psychosomatic medicine. A 250-μg synthetic ACTH (1–24) test (rapid ACTH test) and Beck depression inventory (BDI) were performed for 62 patients presenting with fatigue who visited the Department of Psychosomatic Medicine at Fukuoka Tokushukai Hospital. Patients were divided into 3 groups according to the serum cortisol response to the rapid ACTH test; those with a peak serum cortisol level of <15 μg/dL were defined as the adrenal insufficiency (AI) probable group, ≥15 μg/dL and <18 μg/dL as the AI suspected group, and ≥18 μg/dL as the non-AI group. Patients prescribed anti-depressants, had a BDI ≥16, and/or met the full criteria for major depression were diagnosed with depression. Five (8.0%) and 7 patients (11.3%) were assigned to the AI probable and AI suspected groups, respectively. All others were assigned to the non-AI group. Depression was observed in 37 patients (59.6%; 4 in the AI probable group [80.0%], 4 in the AI suspected group [57.1%], and 29 in the non-AI group [58.0%]). Users of exogenous steroids, such as inhaled steroids for bronchial asthma, were seen in the AI probable group (2; 40.0%), the AI suspected group (3; 42.8%), and the non-AI group (7; 14.0%) (χ2 = 4.761, p = 0.0925). In conclusion, probable or suspected AI was observed in about one-fifth of patients presenting with fatigue at the psychosomatic medical clinic. A CRH test and insulin tolerance test (ITT) may help the he mechanism underlying these possible AIs.
Little is known about type 1 diabetes mellitus (T1DM) impact on the male sexual and reproductive functions. We aim to evaluate the influence of T1DM on male sexual function, quality of sexual life, and sex hormone levels. A total of 57 male patients aged 18 to 50 years (mean = 33) with T1DM (duration mean = 15 years) had a medical examination and completed a set of questionnaires - International Index of Erectile Function-5 (IIEF-5), Beck Depression Inventory (BDI) and Sexual quality of life questionnaire male (SQoL-M). The prevalence of erectile dysfunction was 28.1% (IIEF-5 ≤21). Patients without diabetic nephropathy had better erectile function (p = 0.008). Subjects with better glycemic control (HbA1c <65 mmol/mol) had also better erectile function (p = 0.041). At least 8.8% patients had retrograde ejaculation. Blood serum levels of sex hormones were determined and compared to laboratory reference values of healthy men. Total testosterone level was not significantly changed, sex hormone binding globulin was higher (p < 0.001) and its level correlated with daily insulin dose adjusted to body weight (p = 0.008). Free androgen index and calculated free testosterone were lower (p = 0.013; p < 0.001), estradiol was not significantly changed, LH was higher (p < 0.001), FSH was unchanged, and prolactin was higher (p < 0.001). Prostate-specific antigen (PSA) negatively correlated with HbA1c (p < 0.001). To conclude, we found significant changes in sexual functions and sex hormone blood concentrations that indicate impairment of sexual and reproductive functions in T1DM males.
Those who smoke nicotine-based cigarettes have elevated plasma levels of ghrelin, a hormone secreted from the stomach. Ghrelin has various physiological functions and has recently been shown to be involved in regulating biological rhythms. Therefore, in this study, in order to clarify the significance of the plasma ghrelin increase in smokers, we sought to clarify how nicotine and ghrelin affect the expression dynamics of clock genes using a mouse model. A single dose of nicotine administered intraperitoneally increased plasma ghrelin concentrations transiently, whereas continuous administration of nicotine with an osmotic minipump did not induce any change in the plasma ghrelin concentration. Single administration of nicotine resulted in a transient increase in ghrelin gene expression in the pancreas but not in the stomach, which is the major producer of ghrelin. In addition, in the pancreas, the expression of clock genes was also increased temporarily. Therefore, in order to clarify the interaction between nicotine-induced ghrelin gene expression and clock gene expression in the pancreas, nicotine was administered to ghrelin gene-deficient mice. Administration of nicotine to ghrelin-gene deficient mice increased clock gene expression in the pancreas. However, upon nicotine administration to mice pretreated with octanoate to upregulate ghrelin activity, expression levels of nicotine-inducible clock genes in the pancreas were virtually the same as those in mice not administered nicotine. Thus, our findings indicate that pancreatic ghrelin may suppress nicotine-induced clock gene expression in the pancreas.
Although currently the primary strategy for the treatment of pheochromocytomas is surgery, it is associated with a high risk of intraoperative hemodynamic instability (IHD), even with adequate preoperative medical preparation, which may result in life-threatening situations. The aim of this study was to develop and validate a nomogram for preoperative prediction of IHD related to pheochromocytoma surgery. The development cohort consisted of 283 patients with pheochromocytoma who underwent unilateral laparoscopic or open adrenaletomy at our center between January 1, 2007 and December 31, 2016. The clinicopathological characteristics of each patient were recorded. The least absolute shrinkage and selection operator binary logistic regression model was used for data dimension reduction and feature selection, while multivariable logistic regression analysis was used to develop the prediction model. An independent cohort consisting of 119 consecutive patients from January 1, 2017 to December 31, 2018 was used for validation. The performance of the prediction model was assessed in regards to discrimination, calibration, and clinical usefulness. The predictors of this model included body mass index, coronary heart disease, tumor size, and preoperative use of crystal/colloid fluid. For the validation cohort, the model showed good discrimination with an area under the receiver operating characteristic of 0.767 (95% CI, 0.667–0.857) and good calibration (unreliability test, p = 0.852; Hosmer–Lemeshow test, p = 0.9309). Decision curve analysis demonstrated that the model was clinically useful. This nomogram to facilitate preoperative individualized prediction of IHD in patients with pheochromocytoma may help to improve the perioperative strategy and treatment outcome.
Uterine sarcomas are rare and aggressive gynecologic tumors with poor prognosis; therefore, early diagnosis is crucial for therapy. However, it is very difficult to distinguish uterine sarcomas from leiomyomas which are common benign uterine tumors. Therefore, the development of a diagnostic method that utilizes reliable biomarkers to distinguish uterine sarcomas from leiomyomas is important so as to identify the rare tumors. The candidate factors as novel biomarkers were searched for in public databases and a pilot study was performed for confirmation. Growth differentiation factor-15 (GDF15), progranulin, and osteopontin were identified as candidate biomarkers for diagnosing uterine sarcoma. Thus, developing a rapid and easy method to measure these factors could help establish a screening system for uterine sarcomas. In this study, we developed a novel measurement system for these factors using a compact chemical luminescence immunological automatic analyzer POCubeTM. This assay system, which is based on the flow-through membrane immunoassay, completes the whole process and generates results within 15 min. Serum concentrations of these factors measured via POCubeTM correlated well with those measured using enzyme-linked immunosorbent assay (r = 0.994 for GDF15, r = 0.992 for progranulin, and r = 0.976 for osteopontin). The POCubeTM system provides rapid and easy measurement of these factors, thereby facilitating uterine sarcoma diagnosis.
A 59-year-old woman unaware of having diabetes was transferred due to coma. Upon discovery at home, her consciousness on the Glasgow Coma Scale was E1V2M4, BP 95/84 mmHg, body temperature 34.7°C. On arrival at ER, height was 1.63 m, weight 97 kg, plasma glucose (PG) 1,897 mg/dL, HbA1c 13.6%, osmolality 421 mosm/kg, arterial pH 7.185, lactate 6.34 mmol/L, β-hydroxybutyrate 7.93 mmol/L. With saline and regular insulin infusion, PG was lowered to 1,440 mg/dL at 2 hours and then to 250 mg/dL by Day 3, and consciousness normalized by Day 5. On admission, serum immunoreactive insulin (IRI) was undetectable (<0.03 U/mL), C-peptide immunoreactivity (CPR) undetectable (<0.003 ng/mL), and anti-glutamic acid decarboxylase antibody negative. Following the above-described treatment, fasting PG was 186 mg/dL and CPR 1.94 ng/mL, respectively, on Day 14; 2-h post-breakfast PG 239 mg/dL and CPR 6.28 ng/mL, respectively, on Day 18. The patient discharged on Day 18 with 1,800 kcal diet, 32 U insulin glargine and 40 mg gliclazide. Fifteen months later at outpatient clinic, her HbA1c was 6.9% and 2-h post-breakfast PG 123 mg/dL and CPR 5.30 ng/dL with 750 mg metformin, 10 mg gliclazide and 18 U insulin glargine. Transient, but total cessation of insulin secretion was documented in a patient with type 2 diabetes under severe metabolic decompensation. Swift, sustained recovery of insulin release indicated that lack of insulin at the time of emergency was due to secretory failure, i.e., unresponsive exocytotic machinery or depletion of releasable insulin, rather than loss of beta cells.
Cancer is currently one of the major causes of death in patients with type 2 diabetes mellitus. We previously reported the beneficial effects of the glucagon-like peptide-1 receptor agonist exendin-4 against prostate and breast cancer. In the present study, we examined the anti-cancer effect of the sodium-glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin using a breast cancer model. In human breast cancer MCF-7 cells, SGLT2 expression was detected using both RT-PCR and immunohistochemistry. Ipragliflozin at 1–50 μM significantly and dose-dependently suppressed the growth of MCF-7 cells. BrdU assay also revealed that ipragliflozin attenuated the proliferation of MCF-7 cells in a dose-dependent manner. Because the effect of ipragliflozin against breast cancer cells was completely canceled by knocking down SGLT2, ipragliflozin could act via inhibiting SGLT2. We next measured membrane potential and whole-cell current using the patch clamp technique. When we treated MCF-7 cells with ipragliflozin or glucose-free medium, membrane hyperpolarization was observed. In addition, glucose-free medium and knockdown of SGLT2 by siRNA suppressed the glucose-induced whole-cell current of MCF-7 cells, suggesting that ipragliflozin inhibits sodium and glucose cotransport through SGLT2. Furthermore, JC-1 green fluorescence was significantly increased by ipragliflozin, suggesting the change of mitochondrial membrane potential. These findings suggest that the SGLT2 inhibitor ipragliflozin attenuates breast cancer cell proliferation via membrane hyperpolarization and mitochondrial membrane instability.