Many researchers pay attention to novel secretory factors, such as adipokines or osteokines, secreted by the tissues that were not formerly recognized as classical endocrine organs. The liver also contributes to the onset of various kinds of pathologies of type 2 diabetes and obesity by producing and releasing secretory proteins “hepatokines.” By using the information of gene expression in human livers, we rediscovered selenoprotein P (SeP) and leukocyte cell-derived chemotaxin 2 (LECT2) as hepatokines involved in the onset of glucose intolerance. SeP was previously recognized as a selenium transport protein, but we revealed that SeP causes insulin resistance in the muscle and liver. SeP also reduces VEGF signal transduction in vascular endothelial cells, contributing the impaired angiogenesis in diabetes. Importantly, SeP impairs health-promoting effects of exercise training by suppressing reactive oxygen species (ROS)/adenosine monophosphate-dependent protein kinase (AMPK) pathway in the skeletal muscle through its receptor low-density lipoprotein receptor-related protein 1 (LRP1). LECT2, previously-reported as a neutrophil chemotactic protein, promotes skeletal muscle insulin resistance in obesity. Further studies are necessary to develop new diagnostic or therapeutic procedures targeting hepatokines to combat type 2 diabetes or obesity.

Dysregulation of glucagon secretion plays an important role in the pathogenesis of type 2 diabetes (T2DM). However it hasn’t been elucidated involvement of glucagon dysregulation in pathophysiology of T2DM. Recently a new glucagon sandwich enzyme-linked immunosorbent assay (ELISA) became available that can measure plasma glucagon level with higher accuracy and simpler procedure than the conventional RIA method. We performed OGTT for adult subjects aged 20–69 years to define normal glucose tolerance (NGT, n = 25), borderline glucose intolerance (defined as pre-diabetes mellitus: preDM, n = 15), or diabetes mellitus (DM, n = 13), and we measured glucagon levels with this new ELISA method at fasting and during OGTT. Plasma glucose, insulin, glucagon and active GLP-1 were also measured. This study took place in diabetes outpatient clinic in Kitasato University Hospital and an affiliated outpatient clinic. PreDM and DM exhibited higher fasting plasma glucagon levels than NGT (34.4 ± 4.6 and 44.1 ± 5.0 vs. 20.6 ± 3.6 pg/mL), and statistical significance was observed between NGT and DM (p < 0.05). There was significant correlation between fasting glucagon level and indexes of insulin sensitivity. During OGTT, glucagon levels were less suppressed in DM and preDM than in NGT, whereas no apparent relationship was observed between glucagon and GLP-1 secretion. Significant positive correlation was observed between glucagon levels during OGTT and fasting TG. In conclusion, subjects with mild T2DM exhibited fasting hyperglucagonemia and insufficient suppression to oral glucose load compared to NGT subjects.

The objective of this study was to investigate whether sodium-glucose cotransporter 2 inhibitors (SGLT2i) treatment in patients with type 2 diabetes induced compensatory hyperphagia by reducing fibroblast growth factor 21 (FGF21) secretion. This prospective study was performed in 26 type 2 diabetes patients treated with dapagliflozin (5 mg/day). Hormonal factors associated with glucose metabolism, dietary intakes estimated by brief self-administered diet-history questionnaire (BDHQ), body weight (BW), and body composition were measured at baseline, and 4 and 12 weeks after dapagliflozin. At 12 weeks, HbA1c levels and BW decreased significantly (both p < 0.0001). BMI at baseline was predictive to baseline log₁₀ (FGF21) (p = 0.037). This study showed no change in FGF21, but insulin and glucagon levels decreased significantly (both p < 0.05). Although hyperphagia was found in 10 patients (38.5%), defining hyperphagia as >20% increase in carbohydrate intake, dapagliflozin treatment induced no hyperphagia, when analyzed by all subjects, and there was no significant association between changes in FGF21 levels and carbohydrate intake. On the other hand, a positive correlation between changes in FGF21 levels or carbohydrate intake and BW was observed (both p < 0.005). Taken together, this study demonstrates that the intervention to maintain the reduced levels in FGF21 is beneficial for BW reduction in type 2 diabetes patients treated with SGLT2i.

Primary hyperparathyroidism (PHPT) is a common endocrine disease. Although surgical treatment is curative in most cases, there are few alternative therapies for the hypercalcemia caused by PHPT. Cinacalcet is a positive allosteric modulator of the calcium sensing receptor and was conditionally approved in Japan in 2014 to treat PHPT cases. However, there have been few reports on the outcomes. In our present study, we investigated the efficacy and safety of cinacalcet in 61 PHPT patients who were treated with this agent at our hospital between January 2014 and March 2017. The corrected serum Ca and intact PTH levels were significantly reduced by this treatment, whereas the serum phosphorus levels significantly increased. There were no significant differences in the eGFR or urinary Ca to urinary creatinine ratio between baseline and the maintenance phase. In terms of bone mineral density, there were significant increases observed in the 16 cases for whom a baseline value was available, 11 of whom had been treated for osteoporosis. The most common adverse events from cinacalcet treatment were gastrointestinal symptom, such as nausea and appetite loss. Other adverse events included severe dehydration due to hypercalcemia, myalgia, hypocalcemia, and increased urinary calcium excretion. Seven patients were switched to surgical treatment, and the drug was discontinued in 9 other patients, due to adverse effects. Our present study findings demonstrate that cinacalcet is an effective therapeutic option for PHPT from the perspective of hypercalcemia improvement but that adverse gastrointestinal effects of this drug occur at a frequency of about 10%.

The cyclooxygenase2 (COX-2) enzyme catalyzes the first step of prostanoid biosynthesis, and is known for its crucial role in the pathogenesis of several inflammatory diseases including type 2 diabetes mellitus (T2DM). Although a variety of studies revealed that COX-2 played a role in the IL-1β induced β cell dysfunction, the molecular mechanism remains unclear. Here, using a cDNA microarray and in silico analysis, we demonstrated that inflammatory responses were upregulated in human T2DM islets compared with non-diabetic (ND) islets. COX-2 expression was significantly enhanced in human T2DM islets, correlated with the high inflammation level. PGE2, the catalytic product of COX-2, downregulated the functional gene expression of PDX1, NKX6.1, and MAFA and blunted the glucose induced insulin secretion of human islets. Conversely, inhibition of COX-2 activity by a pharmaceutical inhibitor prevented the β-cell dysfunction induced by IL-1β. COX-2 inhibitor also abrogated the IL-1β autostimulation in β cells, which further resulted in reduced COX-2 expression in β cells. Together, our results revealed that COX-2/PGE2 signaling was involved in the regulation of IL-1β autostimulation, thus forming an IL-1β/COX-2/PGE2 pathway loop, which may result in the high inflammation level in human T2DM islets and the inflammatory impairment of β cells. Breaking this IL-1β/COX-2/PGE2 pathway loop provides a potential therapeutic strategy to improve β cell function in the treatment of T2DM patients.

Crooke’s cell adenoma (CCA) is an aggressive subtype of corticotroph adenoma; however, CCA is associated with a high incidence of low expression of methyl guanine methyl transferase (MGMT), suggesting that temozolomide (TMZ) treatment might be effective for this tumor type. The case of a 56-year-old woman with Cushing’s disease caused by a pituitary CCA is presented. At the age of 38 years, the patient presented to our hospital with polyuria and a visual field defect. MRI and laboratory studies showed a 4.5-cm-diameter pituitary tumor with plasma adrenocorticotropic hormone (ACTH) and serum cortisol levels of more than 500 pg/mL and 40 μg/dL, respectively. At 39 years of age, the patient underwent a craniotomy, and her plasma ACTH and cortisol levels decreased to less than 200 pg/mL and 10 μg/dL, respectively; however, these hormone levels increased gradually to 3,940 pg/mL and 70 μg/dL, respectively, by the time the patient was 56 years old. Histopathological re-examination of the previously resected specimen showed that the pituitary tumor was MGMT-negative CCA. TMZ treatment after the second operation decreased the plasma ACTH levels from 600–800 pg/mL to 70–300 pg/mL. No signs of recurrence were observed in the seven years following these treatments with added prophylactic radiation therapy. These clinical findings suggest that TMZ treatment to patients with CCA accompanied with elevated ACTH may be good indication to induce lowering ACTH levels and tumor shrinkage.

Pituitary adenomas (PAs) are considered the most common intracranial tumor to cause serious morbidity because of dysregulated pituitary hormone secretions. Aberrant expression of microRNAs (miRNAs) is correlated with the development and function of the pituitary gland as well as the tumorigenesis of hypothalamic-pituitary axis-related pituitary tumors. In this study, we showed the differential expression patterns of miRNAs in NFPAs (nonfunctioning pituitary adenomas), GHPAs (growth hormone-secreting pituitary adenomas) and PRLPAs (prolactin-secreting pituitary adenomas) compared to those in three normal pituitary glands using the HiSeq 2000 sequencing system (Illumina). We validated miRNA expression using real-time quantitative polymerase chain reaction (RT-qPCR) analyses of samples from 73 patients (13 GHPAs, 42 NFPAs, and 18 PRLPAs) and 6 normal pituitary gland. We observed that miR-34c-3p was significantly downregulated in our PRLPA samples (p < 0.01), along with miR-34b-5p, miR-378 and miR-338-5p (all p < 0.05). In NFPAs, miR-493-5p was downregulated, and miR-181b-5p was significantly upregulated (p < 0.01). In GHPAs, miR-184 was significantly upregulated (p < 0.05). We observed that the tumor suppressive miR-124-3p was downregulated in both NFPAs and GHPAs. Taken together, we showed distinctive miRNA expression patterns in these three PAs, and these miRNA signatures in PA may have therapeutic potential as novel biomarkers for each type of PA.

Various indicators have been suggested as replacements of body mass index (BMI) for estimating body fat percentage, including the recently introduced relative fat mass (RFM). However, RFM has not been assessed in different ethnicities; therefore, we evaluated whether RFM can be used to estimate body fat percentage in Korean adults and whether RFM is a useful indicator of obesity. Based on the Korea National Health and Nutrition Examination Survey (KNHANES) 2008–2011, we analyzed a total of 18,706 individuals (7,970 men, 10,643 women) aged ≥20 years who underwent dual-energy X-ray absorptiometry. We compared obesity (body fat ≥25% for men, 35% for women) misclassification rate of RFM (≥25 for men, 35 for women) and BMI (≥25 kg/m²). Diagnostic accuracy and optimal cut-offs of BMI and RFM were verified by comparing area under the receiver operating characteristic curve (AUC). RFM and BMI misclassification rates were similar obesity diagnosis based on body fat percentage (27.9% vs. 27.8%) among men. RFM misclassification rate was lower than that of BMI (22% vs. 45%) in women. AUC of RFM was higher in men (AUC: 0.79 vs. 0.78; p = 0.004) and lower in women (AUC: 0.80 vs. 0.83) than those of BMI (p < 0.001). In this study, RFM showed diagnostic accuracy for detecting excess body fat percentage, comparable to that of BMI. Using RFM with BMI could be beneficial in improving the diagnostic accuracy of obesity assessment in women.

This study aimed to investigate if hyperinsulinemia and/or insulin resistance was correlated with the occurrence of papillary thyroid cancer (PTC) in a group of Chinese patients. 258 inpatients were included in the study. According to the postoperative pathology results, all subjects were divided into PTC (n = 153) and control groups (with benign thyroid nodules, n = 105). Body mass index (BMI), fasting glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), thyroid-stimulating hormone (TSH), FT4, FT3, thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TGAb), serum uric acid (UA), and lipid levels. Fasting insulin levels, HOMA-IR values, TPOAb levels, serum TSH levels, and serum uric acid levels in the PTC group were higher than those in the control group (p < 0.05). However, no significant differences in age, gender, BMI, history of hypertension, and the levels of fasting plasma glucose, FT3, FT4, TGAb, total cholesterol, triglyceride, low-density lipoprotein, and high-density lipoprotein were observed between the two groups (p > 0.05). After the multiple logistic regression analysis, the occurrence of PTC was positively associated with fasting insulin (odds ratio [OR] = 1.048, 95% confidence interval [CI]: 1.003–1.096, p = 0.037) and TPOAb levels (OR = 1.001, 95% CI: 1.000–1.002, p = 0.032). Moreover, TPOAb level was positively correlated with vague margin (r = 0.126, p = 0.045) and negatively correlated with homogeneous echo (r = –0.179, p = 0.004). However, fasting insulin levels were not correlated with pathological characteristics of PTC. Hyperinsulinemia and higher TPOAb levels might be the risk factors of PTC, but not disease severity in Chinese patients.

Adrenocortical carcinoma (ACC) is a rare malignancy arising from adrenocortical parenchymal cells. Myxoid ACC is one of the newly identified, rare, but important histological variants of ACC, characterized by the presence of abundant extracellular Alcian Blue-positive myxoid material. Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant cancer predisposition syndrome, and the incidence of ACC in MEN1 patients has been reported to be between 1.4% and 6%. Here, we report the case of a 68-year-old Japanese woman harboring the past history of MEN1 associated with insulinoma, pituitary tumor, and hyperparathyroidism. She presented to our hospital with hypertension and hypokalemia. Imaging studies revealed a right adrenal tumor, and histological examination revealed myxoid ACC. Despite surgical resection of the tumor and mitotane therapy, the patient died 6 months after the surgery. To the best of our knowledge, this is the first reported case of the myxoid variant of ACC in a patient with MEN1. The patient’s clinical course was characterized by the development of both multiple endocrine and non-endocrine neoplasm, hyperaldosteronism, and aggressive biological behavior. This case confirmed that myxoid morphology was also associated with aggressive behavior in ACC, but further studies are required to clarify the association between MEN1 and myxoid ACC.

To examine the efficacy and safety of once-daily insulin degludec/insulin aspart (IDegAsp) or once-daily second-generation basal insulin analogs (insulin degludec and insulin glargine 300 units/mL) in insulin-naïve Japanese adults with type 2 diabetes in routine clinical practice. A 12-week multicenter, open-label, randomized, pilot study was performed in 52 subjects with type 2 diabetes treated with oral antidiabetic drugs (OADs). Subjects were randomized to once-daily IDegAsp (n = 26) or basal insulin (n = 26). The primary endpoint was percent change in HbA1c from baseline to week 12. Furthermore, it was analyzed post hoc in subgroups stratified by baseline HbA1c. During a follow-up period, percent change in HbA1c was not significantly different between the two groups (p = 0.161). Daily insulin doses and frequency of overall hypoglycemia were also similar in the two groups. In post hoc analyses, once-daily basal insulin was more effective than IDegAsp in subjects with HbA1c more than or equal to 8.5% (p < 0.05); however, in subjects with HbA1c less than 8.5%, once-daily IDegAsp showed a significant improvement in percent change in HbA1c at week 12, compared with basal insulin (p < 0.01). Although there was no apparent difference in the HbA1c-lowering effects between two groups, when compared in subjects with HbA1c less than 8.5%, once-daily IDegAsp showed a significant effect in comparison with once-daily basal insulin. These findings suggest that the baseline HbA1c level might provide the important information for choosing IDegAsp or basal insulin in patients insufficiently controlled with OADs. This trial was registered with UMIN (no. UMIN000035431).