The classical model of G protein-coupled receptor (GPCR) activation is the two-state model, in which the GPCR exists in equilibrium between an active and inactive state. Based on this model, GPCR ligands have been classified as agonists, inverse agonists, or antagonists depending on their actions in shifting this equilibrium. Recently, however, accumulating evidence has indicated that GPCRs may exist in multiple active and inactive conformational states. In this situation, each ligand recognizes and stabilizes a specific conformation of the GPCR, leading to a set of specific biological effects. Based on this new model, a unique agonist or a combination of the usual agonist and an allosteric modulator may enable activation of a specific signaling pathway via a GPCR that activates multiple signals (biased agonism, functional selectivity). The calcium-sensing receptor autoantibody that we have identified in the serum of a patient with acquired hypocalciuric hypercalcemia (AHH) is the first example of a biased allosteric modulator of a GPCR working in a pathophysiological context. Our findings may indicate the presence of physiological allosteric modulators and provide new directions for the future drug development.

View full abstract

Thyroid cancer cells were believed to be generated by multi-step carcinogenesis, in which cancer cells are derived from thyrocytes, via multiple incidences of damage to their genome, especially in oncogenes or anti-oncogenes that accelerate proliferation or foster malignant phenotypes, such as the ability to invade the surrounding tissue or metastasize to distant organs, until a new hypothesis, fetal cell carcinogenesis, was presented. In fetal cell carcinogenesis, thyroid tumor cells are assumed to be derived from three types of fetal thyroid cell which only exist in fetuses or young children, namely, thyroid stem cells (TSCs), thyroblasts and prothyrocytes, by proliferation without differentiation. Genomic alternations, such as RET/PTC and PAX8-PPARγ1 rearrangements and a mutation in the BRAF gene, play an oncogenic role by preventing thyroid fetal cells from differentiating. Fetal cell carcinogenesis effectively explains recent molecular and clinical evidence regarding thyroid cancer, including thyroid cancer initiating cells (TCICs), and it underscores the importance of identifying a stem cells and clarifying the molecular mechanism of organ development in cancer research. It introduces three important concepts, the reverse approach, stem cell crisis and mature and immature cancers. Further, it implies that analysis of a small population of cells in a cancer tissue will be a key technique in establishing future laboratory tests. In the contrary, mass analysis such as gene expression profiling, whole genomic scan, and proteomics analysis may have definite limitations since they can only provide information based on many cells.

View full abstract

A 48-year-old woman was diagnosed and treated for Graves’ disease (GD) in 1999 but she discontinued treatment at her own discretion. In 2011, she was admitted to a local hospital for management of thyrotoxic crisis. Treatment with propylthiouracil, iodide potassium (KI), and prednisolone (PSL) was started, which resulted in improvement of the general condition. PSL and KI were discontinued before she was transferred to our hospital. At the local hospital, fasting plasma glucose (FPG) was 212 mg/dL and hemoglobin A1c concentration was 11.2%; intensive insulin therapy had been instituted. Upon admission to our hospital, FPG level was 122 mg/dL, but insulin secretion was compromised, suggesting aggravation of thyroid function and deterioration of glycemic control. The FPG level increased to 173 mg/dL; continuous glucose monitoring (CGM) identified dawn phenomenon at approximately 0400 h. Resumption of KI resulted in improvement of FPG and disappearance of the dawn phenomenon, as assessed by CGM. These results indicate that in patients with compromised insulin secretion, hyperthyroidism can induce elevation of not only postprandial blood glucose, but also FPG level due to the dawn phenomenon and that the dawn phenomenon can be alleviated with improvement in thyroid function. To our knowledge, no studies have assessed glucose variability by CGM before and after treatment of Graves’ disease. The observations made in this case shed light on the understanding of abnormal glucose metabolism associated with Graves’ disease.

View full abstract

Postprandial hyperglycemia is considered as a risk factor of cardiovascular disease. We hypothesized that early post-load hyperglycemia might be more useful surrogate marker to assess atherosclerosis than plasma glucose (PG) level at 120 minutes because the peak of post-load glucose by 75gOGTT is usually shown at 60 minutes. 75gOGTT and carotid echography were investigated in 108 subjects who visited our hospital to examine impaired glucose tolerance. The association of post-load plasma glucose and insulin levels with intima-media thickness (IMT) was examined. Simple correlation analyses showed that fasting PG (FPG) (r=0.26, p=0.013), PG60 (r=0.40, p<0.001), PG90 (r=0.29, p=0.008), area under curve for PG (AUC-PG) (r=0.33, p=0.003), HbA1c (r=0.30, p=0.005), amount of PG increase at 60 minutes (PGΔ60) (r=0.39, p=0.002), and PGΔ90 (r=0.27, p=0.016), were significantly correlated with IMT. Multiple regression analysis using IMT as a dependent variable and PG60, FPG, HbA1c, and AUC-PG as independent variables showed that PG60 was only significantly and positively correlated with IMT (β=0.59, p=0.042). Moreover, PG60 and PGΔ60 were significantly and positively associated with IMT even after additional adjustment for classical atherosclerosis risk factors (β=0.30, p=0.005 and β=0.50, p=0.037, respectively). The cut-off values of PG60 and PGΔ60 to detect atherosclerosis (IMT > 1.1mm) were 188 and 101 mg/dL, respectively (p<0.01). These findings show that early post-load hyperglycemia, particularly PG60 is a novel risk factor of atherosclerosis and useful to assess it.

View full abstract

Trichostatin A (TSA) is a selective inhibitor of mammalian histone deacetylase. In the present study, TSA was found to selectively increase gene expression of the pituitary gonadotropin β-subunit of follicle-stimulating hormone (FSH). Stimulation of mouse pituitary gonadotroph cell lines, LβT2, with TSA for 24 h resulted in no change in mRNA expression of the α- and LHβ-subunit. On the other hand, FSHβ-subunit mRNA expression was significantly increased in a dose-dependent fashion. Similarly, specific induction of the FSHβ-subunit gene with TSA stimulation was observed in primary cultures of rat pituitary cells. Histone acetylation in whole cell lysates of LβT2 cells was significantly increased after TSA treatment, but not gonadotropin-releasing hormone (GnRH) treatment. The effect of TSA on FSHβ mRNA expression was prominent compared to that of GnRH; however, TSA-stimulated FSHβ mRNA expression was significantly reduced with combined TSA and GnRH treatment. TSA caused a slight increase in extracellular signal-regulated kinase (ERK) phosphorylation, while GnRH-increased ERK phosphorylation was potentiated in the presence of TSA. In addition, TSA, but not GnRH, significantly stimulated gene expression of retinaldehyde dehydrogenase 1 (RALDH1), a retinoic acid (RA) synthesizing enzyme involved in cell differentiation. These findings demonstrate that TSA specifically increases FSHβ subunit gene expression with a concomitant increase in whole cell histone acetylation. Moreover, although GnRH is a stimulator of FSHβ gene expression, it interfered with the stimulatory effect of TSA on FSHβ mRNA expression, without modification of TSA-increased whole cell histone acetylation. This suggests that the mechanisms of TSA and GnRH-induced gonadotropin subunit gene expression are entirely distinct.

View full abstract

Previous studies have shown that approximately 50% patients at risk of cardiovascular disease do not achieve lipid management goals. Thus, improvements dyslipidemia management are needed. We investigated the clinical choice and efficacy of second-line treatments for dyslipidemia in the Japanese clinical setting. Using a retrospective cohort design, we collected lipid profile data from patients who had been treated with hypolipidemic agents at a stable dosage for at least 12 weeks. These patients had then been administered a second-line treatment for dyslipidemia because they had not achieved the low-density lipoprotein cholesterol (LDL-C) management goals. We included data from 641 patients in our analysis. The top three choices for second-line treatment were adding ezetimibe, switching to strong statins (statin switching), and doubling the original statin dosage (statin doubling). Adding ezetimibe, statin switching, and statin doubling decreased LDL-C levels by 28.2 ± 14.5%, 23.2 ± 24.4%, and 23.5 ± 17.2%, respectively. Among these three strategies, adding ezetimibe decreased LDL-C levels to the maximum extent. In patients with dysglycemia, baseline-adjusted change in hemoglobin A1c (HbA1c) levels decreased slightly in the adding-ezetimibe, statin-switching, and statin-doubling groups, but the differences were not statistically significant among the groups (−0.10 ± 0.62%, −0.22 ± 0.54%, and −0.12 ± 0.52%, p = 0.19). In conclusion, the most common second-line treatment options for dyslipidemia were adding ezetimibe, statin switching, or statin doubling. Adding ezetimibe resulted in the highest reduction in LDL-C levels. These strategies did not increase HbA1c levels when administered with conventional diabetes treatment.

View full abstract

There is a paucity of information on perinatal data regarding gestational diabetes mellitus (GDM) by the new criteria from a real experience because the number of health care associations implementing the new criteria is still limited. The aim of this study is to investigate perinatal features of the new criteria-defined GDM. We reviewed a total of 995 women with singleton pregnancy that underwent GDM screening followed by a diagnostic oral glucose tolerance test (OGTT). All women found to have GDM underwent self-monitoring of blood glucose measurements as well as dietary management. Insulin treatment was initiated when dietary treatment did not achieve the glycemic goal. Of the 995 women, 141 had GDM (14.2%): 104 with one, 27 with two, and 10 with three abnormal OGTT values. Women with two or three abnormal OGTT values (2/3-AV) needed insulin treatment more frequently than those with one abnormal OGTT value (1-AV) (70.3% vs 23.1%, P < 0.0001). After adjustment for age, pregravid overweight, gestational weeks at diagnosis, a first-degree family history of diabetes was correlated with the implementation of insulin treatment in women with 1-AV (adjusted odds ratio 3.9; 95% Confidence Interval 1.7-9.2; P = 0.001). When compared perinatal outcomes between women with normal glucose tolerance and GDM, fetal growth and the occurrence of pregnancy-induced hypertension were comparable between the two groups. Our data suggest that the IADPSG-defined GDM with 1-AV show less severe glucose intolerance, but might be at risk of insulin requirement when a first-degree family history of diabetes exists.

View full abstract

Recent studies have demonstrated that T-helper 17 lymphocytes (Th17), which produce mostly IL-17, play a major role in several autoimmune diseases commonly thought to be Th1-related, including Hashimoto’s thyroiditis (HT). IL-23, a member of the IL-12 cytokine family, is known to guide T cells toward the Th17 phenotype and its serum levels are increased in several autoimmune disease. Few data are available in the literature on IL-23 in HT. Using IL-23 Quantikine ELISA Kit (lower limit of detection 2.7 pg/mL) we analyzed the serum levels of IL-23 in 81 HT patients (75 females and 6 males, aged 14-70; mean age 39±17 years), and an age- and sex-matched group of 80 healthy persons. Both patients and controls did not receive any treatment. The positive detection rates of serum IL-23 were significantly higher in patients with HT: 56% of HT patients had detectable IL-23 in serum compared to 36% of healthy subjects (Chi χ² test, p=0.014). Moreover, HT patients had significantly higher serum concentrations of IL-23 (157.38 ± 17.92 pg/mL) in comparison with healthy controls (21.46 ± 5.4 pg/mL; p <0.0001). No significant correlation was found between serum levels of IL-23 and Tg-Ab or TPO-Ab levels, as well as with TSH values, in HT patients. In conclusion, serum IL-23 is increased in euthyroid and untreated HT patients, as compared to healthy subjects. Our data suggest that IL-23 would play a role in the pathogenesis of HT.

View full abstract

The effects of exenatide on glycemic control, lipid metabolism, blood pressure, and gastrointestinal symptoms were investigated in obese Japanese patients with type 2 diabetes mellitus. Twenty-six outpatients were enrolled and administered 5 μg of exenatide twice daily. If there was insufficient weight loss and/or insufficient improvement in glycemic control, the dose was increased to 10 μg twice daily. Follow-up was continued until the 12^th week of administration. Hemoglobin A1c, glycoalbumin, fasting plasma glucose, body weight, fasting serum C-peptide, serum lipids, blood pressure, and pulse rate were measured before and after the observation period. In the initial phase of exenatide therapy, each patient received a diary to record gastrointestinal symptoms. During treatment with exenatide, hemoglobin A1c decreased significantly and serum C-peptide increased significantly. Body weight, low-density lipoprotein cholesterol, and systolic blood pressure decreased significantly. Nausea was the most frequent gastrointestinal symptom and occurred in 16 patients. Its onset was noted at a mean of 1.7 h after injection, the mean duration was 1.1 h, and it continued for a mean of 9.3 days after the initiation of administration. Patients with nausea showed a significant decrease in hemoglobin Alc, glycoalbumin, or body weight compared with those without nausea. These findings suggest that a more marked improvement in metabolic parameters by exenatide can be partly dependent on the manifestation of gastrointestinal symptoms.

View full abstract

The aim of this study was to determine the effects of pre-gestational body mass index on pregnancy outcomes of women with gestational diabetes in Japan. A multi-institutional retrospective study was performed. We examined pregnant women who met the former criteria for gestational diabetes in Japan, receiving dietary intervention with self-monitoring of blood glucose with or without insulin therapy. Women with gestational diabetes were divided into three groups according to pre-gestational body mass index: body mass index <25 (control group), 25 ≤ body mass index <30 (overweight group), body mass index ≥30 (obese group). Data from a total of 1,758 eligible women were collected from 40 institutions. Participants included 960 controls, 426 overweight women, and 372 obese women with gestational diabetes. Gestational weight gain was highest in the control and lowest in the obese group. The prevalences of chronic hypertension and pregnancy induced hypertension were higher in the overweight and obese groups than in the control group. Multiple logistic regression analysis revealed pre-gestational body mass index, gestational weight gain, chronic hypertension, and nulliparity to be associated with the onset of pregnancy induced hypertension, while the 75-g OGTT results were unrelated to pregnancy induced hypertension. The prevalence of large-for-gestational age was lower in infants born to obese women than in those born to overweight or control women. The present results suggest that medical interventions for obese women with gestational diabetes may contribute to reducing the prevalence of large-for-gestational age but would not achieve marked reductions in maternal complications.

View full abstract

The aim of this study was to evaluate the relative contribution of serum adipokines and adipokines from the patient’s omentum-derived adipocytes (PODAs) and visceral adipose tissue (VAT) of Japanese patients with severe obesity. Secondarily, we analyzed patients’ metabolic changes after laparoscopic sleeve gastrectomy (LSG). Twenty-three LSG patients and 23 non-obese patients undergoing elective abdominal surgery were enrolled. The levels of adipokines in the serum and the PODAs were measured. The clinical and metabolic data were evaluated at 6 months after LSG. The mean serum leptin levels and the mean serum plasminogen activator inhibitor type-1 (PAI-1) levels were significantly greater (p < 0.001) and the mean adiponectin levels were significantly lower in the LSG group (p = 0.006). In the measurements of the PODAs, the mean leptin levels (p < 0.001) were significantly greater and the mean adiponectin levels (p < 0.001) were significantly lower in the LSG group. The mean BMI (-12 kg/m², p < 0.001) and mean VAT (-135.5 cm², p = 0.001) were significantly decreased after LSG. In nine patients with type 2 diabetes mellitus, the reduction in VAT correlated with the change in high-sensitivity C-reactive protein (p = 0.006) and the homeostasis model of assessment of insulin resistance (p = 0.001). After 6 months, LSG markedly improved most obesity-related comorbidities. Our results suggest that LSG may contribute to VAT reduction, improved adipocyte hormone levels, and changes in gut physiology and endocrinology.

View full abstract

The majority of the cases diagnosed as primary aldosteronism (PA) are caused by aldosterone-producing adenoma (APA) or idiopathic hyperaldosteronism (IHA). Histopathologically, both IHA and adjacent adrenal glands of APA demonstrate remodeled subcapsular zone (RSZ) but these zones in two disorders are markedly different in terms of steroidogenesis. 3β-Hydroxysteroid dehydrogenase/Δ⁵-Δ⁴ isomerase (3β-HSD) expression has been known to be activated synergistically by GATA6 and SF1, and repressed by DAX1 through abolishing the activation. Nerve growth factor-induced clone B (NGFIB) is also known as one of the transcription factors to bind to and activate 3β-HSD promoter. The results of our immunohistochemical analysis demonstrated the expression levels of 3β-HSD in RSZ of IHA were higher than in RSZ of adjacent adrenals of APA, while those in the zona glomerulosa (ZG) of normal adrenal gland (NA) were in between these two RSZs. The expression levels of GATA6, SF1 and DAX1 did not prominently differ among these three types of adrenals, especially between in RSZs of IHA and APA cases, indicating the marked difference of 3β-HSD expression was unlikely to be explained by the levels of these three factors. However, the levels of NGFIB expression were significantly higher in RSZ of IHA than in RSZ of adjacent adrenals of APA and the ZG of NA (P<0.05), which may partly account for the expression levels of 3β-HSD among the three groups of adrenals. These results may imply NGFIB plays important roles in the marked differences in steroidogenic functions in the two distinct types of RSZ of PA cases.

View full abstract

A permanent hypoparathyroidism is a problematic complication of total thyroidectomy. In this study, we investigated its incidence and how to avoid it at the time of completion total thyroidectomy after hemithyroidectomy. Eight of the 154 patients who underwent completion total thyroidectomy as the second surgery (5%) after hemithyroidectomy (two-surgery group) showed a permanent hypothyroidism. Patients without parathyroid autotransplantation either at initial or second surgery were more likely to show a permanent hypoparathyroidism. In the subset of 74 patients in two-surgery group, who underwent bilateral central dissection, 6 (8%) had a permanent hypoparathyroidism. The incidence was higher than those in control group who underwent total thyroidectomy with bilateral central dissection at one time, which was 2%. However, all 6 patients showing a permanent hypoparathyroidsm underwent bilateral central dissection in initial surgery and none of the patients who underwent bilateral central dissection in twice had a permanent hypoparathyroidism. Taken together, we can conclude that 1) in initial surgery of hemithyroidectomy, we have to carefully search the parathyroid glands and if dissected, they should retrieved and autotransplanted to save the patients from a permanent hypoparathyroidism when they undergo second surgery in future, and 2) hemithyroidectomy with bilateral central dissection significantly increases the risk of permanent hypoparathyroidism and only ipsilateral dissection is better when we do not perform total thyroidectomy.

View full abstract