Accumulating evidence has shown that bone and glucose metabolism are closely associated with each other. Since the risk of osteoporotic fractures is increased in patients with diabetes mellitus (DM), osteoporosis is recently recognized as one of diabetic complications, called DM-induced bone fragility. Previous studies showed that collagen cross-links of advanced glycation end products (AGEs) and dysfunctions of osteoblast and osteocyte are involved in DM-induced bone fragility. Circulating levels of AGEs and homocysteine are increased in patients with DM, and they directly impair the functions of osteoblast and osteocyte, resulting in decreased bone formation and bone remodeling. On the other hand, bone is recently recognized as an endocrine organ. Previous studies based on in vitro and animal studies showed that osteocalcin, which is specifically expressed in osteoblasts and secreted into the circulation, may regulate glucose homeostasis. Although several clinical studies reported the relationship between osteocalcin and glucose metabolism, further large-scale and intervention studies are necessary to confirm the beneficial effects of osteocalcin on glucose metabolism in human. It has been shown that adenosine monophosphate-activated protein kinase (AMPK), an intracellular energy sensor, is involved in bone metabolism. Adiponectin and metformin stimulate osteocalcin expression and the differentiation of osteoblasts via AMPK activation. Also, AMPK activation protects against oxidative stress-induced apoptosis of osteocytes. These findings suggest that AMPK in osteoblasts and osteocytes may be a therapeutic target for DM-induced bone fragility.

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GPR120 is a G-protein-coupled receptor that is activated by long-chain fatty acids. In our previous study, GPR120 expression was detected in gonadotrophs of the mouse anterior pituitary gland. It is well known that the function of anterior pituitary cells is largely under the influence of circulating sex steroids. Thus, in the present study, we investigated the modulatory roles of the ovarian hormones, estrogen (E2) and progesterone (P), on the expression levels of GPR120 mRNA in mouse pituitary glands. GPR120 mRNA expression levels in the pituitary gland were increased after ovariectomy or P treatment, and were decreased after the administration of E2. Simultaneous injection of E2 and P interfered with the action of E2 on GPR120 mRNA expression. The GnRH antagonist, Cetrotide, did not inhibit the increase in GPR120 expression in ovariectomized (OVX) animals. In addition, immunohistochemistry revealed that more than 95.4% of GPR120 immunoreactive cells colocalized with the luteinizing hormone β (LHβ) in the anterior pituitary gland of intact, ovariectomized (OVX), estradiol-primed OVX (OVX+E2), or progesterone-primed OVX (OVX+P) animals. Furthermore, GPR120 mRNA expression levels were not significantly different in the pituitary gland of females throughout the ovarian cycle. It is suggested that low levels of P may mask the inhibitory effect of estradiol on the synthesis of GPR120 in the estrous stage in intact animals. These results demonstrate that ovarian hormones may directly regulate GPR120 expression in the reproductive cycle at the pituitary level.

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Dexamethasone-induced Ras-related protein 1 (Rasd1) is a member of the Ras superfamily of monomeric G proteins that have a regulatory function in signal transduction. Here we investigated the role of Rasd1 in regulating estrogen-induced gene expression in primary cultures of rat anterior pituitary cells. Rasd1 mRNA expression in anterior pituitary cells decreased after treatment with forskolin or serum and increased after treatment with 17β-estradiol (E2). Increases in Rasd1 mRNA expression occurred as early as 0.5 h after E2 treatment, peaked at 1 h and were sustained for as long as 96 h. This rapid and profound increase in Rasd1 mRNA expression induced by E2 was also seen in GH4C1 cells, an estrogen receptor-positive somatolactotroph cell line. Among pituitary estrogen-responsive late genes studied, basal mRNA expression of Pim3 and Igf1 genes was decreased by RNA interference-mediated knockdown of Rasd1 expression, whereas basal expression of the Giot1 gene was increased. Moreover, Rasd1 knockdown enhanced stimulation of Pim3 mRNA expression and attenuated inhibition of Fosl1 mRNA expression 24 h after E2 treatment. These changes in mRNA expression were accompanied by enhanced activity of promoters containing CRE, AP-1 and SRE binding sequences. These results suggest that Rasd1 is an estrogen-responsive immediate early gene and modulates E2 induction of at least several late genes in anterior pituitary cells.

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Although the current remission criteria for acromegaly are clear and concise, some pitfalls have been reported in early endocrinological evaluation after surgery. To evaluate the long-term (>4 year) outcome and to detect the pitfalls in early evaluation, we retrospectively reviewed 128 patients with acromegaly who underwent primary transsphenoidal surgery during 2011 and 2012. These included 66 men and 62 women, aged from 7 to 76 (mean 46) years old. 49 patients (38.3%) were preoperatively treated with somatostatin analog (SSA). Follow-up period ranged from 52 to 75 (63) months. Long-term remission using the current consensus criteria was achieved in 107 patients (83.6%), 105 of which patient had achieved remission in early evaluation. In 5 patients with preoperative SSA treatment, IGF-1 levels re-elevated more than one year after surgery. Five female patients without pretreatment with SSA showed delayed normalization of IGF-1 between 13 to 27 months postoperatively, two of which patients satisfied the remission criteria. In conclusion, the long-term results can be reliably predicted by the remission criteria early after surgery in most patients with acromegaly. For the accurate evaluation within a year after surgery, however, influence of preoperative treatment with SSA, delayed normalization of IGF-1, and poor GH suppression due to low insulin resistance must be considered, particularly in women.

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The aim of this study was to define the effectiveness and safety of ultrasound(US)-guided percutaneous microwave ablation(MWA) for benign thyroid nodules with one session treatment. A total 121 benign thyroid nodules in 100 euthyroid patients underwent MWA in one medical center between August 2014 and December 2015. MWA was performed with an internally cooled antenna under local anesthesia. The volume of the nodule, cosmetic score and symptom score were compared before and after the procedure. The volume reduction rate(VRR) was also evaluated. The side effects and complications were observed. As a result, microwave ablation was associated with a significant decrease in nodule volume{1.05±1.05mL (0.08~4.33mL)vs 8.56±4.21mL(4.05~22.66mL), p <0.001} at 12-month follow-up. The largest diameter was also decreased {1.36±0.53cm(0.60~3.73cm) vs 2.94±0.55cm(2.00~4.40cm) , p<0.001}. The symptom score and cosmetic score were decreased significantly after the procedure(1.71±0.68 vs 3.31±1.13, p<0.001; 1.16±0.37 vs 2.37±0.94, p<0.001). The VRR was 57.66±22.95%, .70.23±20.07%, 85.97±14.04% at 3-, 6- and 12-month follow-up after ablation , respectively. Two patients(2.0%) experienced hoarseness and recovered within 2 months. Two patients(2.0%) developed slight burn on cervical skin. One case(1%) developed Horner Syndrome, recovered within 2 months. Ultrasound-guided percutaneous microwave ablation developed significant volume reduction on benign thyroid nodules, with achieving improvement in symptom score and cosmetic grading. The treatment was well tolerated.

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Thyroid peroxidase (TPO) deficiency, caused by biallelic TPO mutations, is a well-established genetic form of congenital hypothyroidism (CH). More than 100 patients have been published, and the patients have been diagnosed mostly in the frame of newborn screening (NBS) programs. Correlation between clinical phenotypes and TPO activity remains unclear. Here, we report clinical and molecular findings of two unrelated TPO mutation-carrying mildly hypothyroid patients. The two patients were born at term after an uneventful pregnancy and delivery, and were NBS negative. They sought medical attention due to goiter at age 8 years. Evaluation of the thyroid showed mild elevation of serum TSH levels, normal or slightly low serum T₄ levels, high serum T₃ to T₄ molar ratio, high serum thyroglobulin levels, and high thyroidal ¹²³I uptake. We performed next-generation sequencing-based genetic screening, and found that one patient was compound heterozygous for two novel TPO mutations (p.Asp224del; c.820-2A>G), and the other was homozygous for a previously known mutation (p.Trp527Cys). In vitro functional analyses using HEK293 cells showed that the two amino acid-altering mutations (p.Asp224del and p.Trp527Cys) caused partial loss of the enzymatic activity. In conclusion, we report that TPO mutations with residual activity are associated with mild TPO deficiency, which is clinically characterized by marked goiter, mild TSH elevation, high serum T₃ to T₄ molar ratio, and high serum thyroglobulin levels. Our findings illuminate the hitherto under-recognized correlation between clinical phenotypes and residual enzymatic activity among patients with TPO deficiency.

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Many cytological studies on medullary thyroid carcinoma (MTC) have been reported; however, such studies in large series of patients with MTC have not been performed. We investigated MTC at a single institution in Japan using fine-needle aspiration cytology (FNAC), and aimed to establish a preoperative diagnostic algorithm for MTC. FNAC was performed in 119 of 149 patients with MTC (79.9%) who ultimately underwent surgical resection. Moreover, 22 of 56 hereditary MTC (39.3%) were diagnosed preoperatively without FNAC by their high serum calcitonin levels or increased response to calcium stimulation (11 cases each), as well as RET mutation analysis. On FNAC, 76.5% of nodules were categorized as ‘malignancy’ or ‘suspicious for malignancy’. The sensitivity and specificity of calcitonin measurement in aspiration needle wash-out fluid and in immunocytochemical staining for calcitonin were 96.3% and 92.3% respectively. We proposed an algorithm for preoperative diagnosis of MTC utilizing FNAC: When thyroid nodules are highly suspicious for MTC by their clinical and ultrasonographic features, serum calcitonin measurement with or without a calcium stimulation test is required. Furthermore, FNAC should be performed for patients who do not have those findings. When there is a possibility of MTC at the time of FNAC, calcitonin measurement using needle wash-out fluid is a reliable diagnostic tool. When MTC is suspected on cytological examination, immunocytochemical staining for calcitonin is useful for confirming MTC diagnosis.

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Fatty liver disease and metabolic syndrome (MetS) are both shown to increase the risk of type 2 diabetes. The aim of this study was to investigate the combined effect of fatty liver and MetS on incident diabetes. In this cohort study of 17,810 participants, fatty liver was diagnosed by abdominal ultrasonography and MetS was defined by a joint interim statement. We divided the participants into four groups according to the presence of fatty liver and/or MetS. Type 2 diabetes was defined as HbA1c ≥6.5%, fasting plasma glucose ≥7.0 mmol/L or treatment for diabetes. During the follow up examination (median 5.1 years), 804 participants developed diabetes. Compared with non-MetS without fatty liver, hazard ratios (HR) for incident diabetes after adjusting for age, body mass index, smoking status, exercise habit, alcohol consumption, family history of diabetes logarithm of alanine aminotransferase and fasting plasma glucose, were as follow: 2.35 (95 % CI 1.91-2.89, p<0.001) in non-MetS with fatty liver, 1.70 (95% CI 1.30-2.20, p<0.001) in MetS without fatty liver, and 2.33 (95% CI 1.85-2.94, p<0.001) in MetS with fatty liver. In addition, adjusted HRs for incident diabetes compared with MetS without fatty liver were 1.39 (95% CI 1.07-1.80, p=0.012) in non-MetS with fatty liver and 1.38 (95% CI 1.07-1.79, p=0.013) in MetS with fatty liver. Fatty liver affects more on the risk of incident diabetes than MetS. To prevent the further risk of diabetes, we should pay more attention to fatty liver.

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Well-differentiated thyroid carcinomas have driver mutations involving growth factor receptor-tyrosine kinases (RTKs) or their intracellular signaling pathway, that is, the mitogen-activated protein kinase (MAPK) pathway. Sorafenib is a multikinase inhibitor of RTKs and the MAPK pathway and has recently been used for the treatment of unresectable well-differentiated thyroid carcinoma. In normal thyroid follicular cells, stimulation of the thyroid-stimulating hormone (TSH) receptor activates the cyclic adenosine monophosphate (cAMP) pathway and promotes cell growth as well as hormonal secretion. However, an adenylyl cyclase (AC) activator, forskolin, has been reported to suppress the growth of thyroid carcinoma cells. To clarify the roles of the MAPK and cAMP pathways in proliferation of well-differentiated thyroid carcinoma cells, we compared the effects of sorafenib and forskolin in in vitro models. Sorafenib inhibited constitutive activation of the MAPK pathway, cyclin-dependent kinase 4 (CDK4), and phosphorylated retinoblastoma protein (RB) in 3 well-differentiated carcinoma cell lines, but it did not show sufficiently effective suppression of cell growth. Forskolin significantly suppressed the growth of all 3 cell lines and also activated the cAMP pathway and inhibited expression of cyclin D1. Our results suggest that activation of the cAMP pathway could be more potent than activation of the MAPK pathway in suppressing proliferation of well-differentiated thyroid cancer cells. We postulate that the AC activator suppresses growth of thyroid carcinoma cells through undetermined mechanisms.

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We investigated whether glucotoxicity of β-cell function could be eliminated after medical nutrition therapy (MNT) without forced correction of hyperglycemia by anti-diabetic medications including exogenous insulin administration. We analyzed newly diagnosed type 2 diabetic outpatients with hemoglobin A1c (HbA1c) of 10.1 ± 1.5%, who were treated by MNT at least for three months, without any aid of anti-diabetic medications. The β-cell function was calculated as the product of the ΔIns_0-120/ΔGlu_0-120 and the Matsuda index, where ΔIns_0-120/ΔGlu_0-120 represents the ratio of the incremental concentrations of insulin to those of glucose during the 0- to 120-min time periods under a 75-g oral glucose tolerance test. After MNT, HbA1c levels were reduced to 7.0 ± 1.0% (p < 0.001). The β-cell function was significantly improved (n = 13; p = 0.001; effect size d = 1.9). Fasting plasma glucose became below 7.0 mmol/l in 57% (8/13), and 120-minute plasma glucose became below 11.1 mmol/l in 43% (6/13). The β-cell function after MNT was significantly correlated with HbA1c levels achieved after MNT (Pearson’s correlation coefficient r = -0.62, p = 0.025). In conclusion, the β-cell dysfunction was ameliorated after MNT without glucose-lowering pharmacotherapy in newly diagnosed type 2 diabetic outpatients who presented extreme hyperglycemia.

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