Showing papers in "Endocrine in 2015"

Selenium: an element for life

Abstract: This review aims to illustrate the importance of selenium (Se) for maintenance of overall health, especially for the thyroid, immunity, and homeostasis. Furthermore, it outlines the role of Se in reproduction and in virology and discusses the effects of Se supplementation in critical illness. The multifaceted aspects of this essential nutrient have attracted worldwide clinical and research interest in the last few decades. Se exerts its activity in the form of the aminoacid selenocysteine incorporated in selenoproteins. The impact of Se administration should be considered in relation to its apparent U shaped effects, i.e., exhibiting major advantages in Se-deficient individuals but specific health risks in those with Se excess. Addition of selenium to the administration of levothyroxine may be useful in patients with low Se intake and with mild-form or early-stage Hashimoto’s thyroiditis (HT). Serum Se concentration (possibly also at tissue level) decreases in inflammatory conditions and may vary with the severity and duration of the inflammatory process. In such cases, the effect of Se supplementation seems to be useful and rational. Meanwhile, Se’s ability to improve the activity of T cells and the cytotoxicity of natural killer cells could render it effective in viral disease. However, the evidence, and this should be stressed, is at present conflicting as to whether Se supplementation is of benefit in patients with HT, though there are indications that it is advantageous in cases of mild/moderate Graves’ Orbitopathy. The role of Se in type 2 diabetes mellitus (T2DM) is ambiguous, driven by both Se intake and serum levels. The evidence that insulin and glycaemia influence the transport and activity of Se, via regulatory activity on selenoproteins, and that high serum Se may have a diabetogenic effect suggests a ‘Janus-effect’ of Se in T2DM. Though the evidence is not as yet clear-cut, the organic form (selenomethionine), due to its pharmacokinetics, is likely to be more advantageous in long-term prevention, and supplementation efforts, while the inorganic form (sodium selenite) has proven effective in an acute, e.g., sepsis, clinical setting. Recent data indicate that functional selenoprotein single-nucleotide polymorphisms (SNPs) may interfere with Se utilization and effectiveness.

Risk of bone fractures associated with glucagon-like peptide-1 receptor agonists' treatment: a meta-analysis of randomized controlled trials.

Abstract: Traditional anti-diabetic drugs may have negative or positive effects on risk of bone fractures. Yet the relationship between the new class glucagon-like peptide-1 receptor agonists (GLP-1 RA) and risk of bone fractures has not been established. We performed a meta-analysis including randomized controlled trials (RCT) to study the risk of bone fractures associated with liraglutide or exenatide, compared to placebo or other active drugs. We searched MEDLINE, EMBASE, and clinical trial registration websites for published or unpublished RCTs comparing the effects of liraglutide or exenatide with comparators. Only studies with disclosed bone fracture data were included. Separate pooled analysis was performed for liraglutide or exenatide, respectively, by calculating Mantel–Haenszel odds ratio (MH-OR). 16 RCTs were identified including a total of 11,206 patients. Liraglutide treatment was associated with a significant reduced risk of incident bone fractures (MH-OR = 0.38, 95 % CI 0.17–0.87); however, exenatide treatment was associated with an elevated risk of incident bone fractures (MH-OR = 2.09, 95 % CI 1.03–4.21). Publication bias and heterogeneity between studies were not observed. Our study demonstrated a divergent risk of bone fractures associated with different GLP-1 RA treatments. The current findings need to be confirmed by future well-designed prospective or RCT studies.

Seasonal variations in serum 25-hydroxy vitamin D levels in a Swedish cohort

Abstract: To study seasonal inter-individual and intra-individual variations in serum 25-hydroxy vitamin D (25(OH)D) and to explore parameters associated with 25(OH)D in a healthy Swedish adult population. 540 blood donors (60 % men; mean age 41 ± 13 years) and 75 thrombocyte donors (92 % men, aged 46 ± 11 years) were included. Serum was collected during 12 months and analyzed for 25(OH)D and parathyroid hormone (S-iPTH). The blood donors answered questionnaires concerning vitamin D supplements, smoking, physical activity, sunbed use and sun holidays. Repeated serum samples were collected from the thrombocyte donors to study the intra-individual variations in S-25(OH)D. S-25(OH)D varied greatly over the year correlating with the intensity of the UV-B irradiation (rS = 0.326; p < 0.001). During January–March, a S-25(OH)D level below the thresholds of 50 and 75 nmol/L was observed in 58 and 88 %, respectively, and during July–September in 11 and 50 % (p < 0.001). S-25(OH)D was negatively correlated with body mass index and S-iPTH, but was significantly higher in holiday makers in sunny destinations, sunbed users, non-smokers, and in the physically active. The intra-individual analyses showed a mean increase in S-25(OH)D by 8 nmol/L/month between April and August. Approximately 75 % had serum 25(OH)D values <75 nmol/L during 75 % of the year and 50 % had serum 25(OH)D <50 nmol/L during 50 % of the year. Serum 25(OH)D was strongly associated with parameters related to sun exposure, but only weakly with intake of vitamin D supplements.

Hypothalamic-autonomic control of energy homeostasis

Abstract: Regulation of energy homeostasis is tightly controlled by the central nervous system (CNS). Several key areas such as the hypothalamus and brainstem receive and integrate signals conveying energy status from the periphery, such as leptin, thyroid hormones, and insulin, ultimately leading to modulation of food intake, energy expenditure (EE), and peripheral metabolism. The autonomic nervous system (ANS) plays a key role in the response to such signals, innervating peripheral metabolic tissues, including brown and white adipose tissue (BAT and WAT), liver, pancreas, and skeletal muscle. The ANS consists of two parts, the sympathetic and parasympathetic nervous systems (SNS and PSNS). The SNS regulates BAT thermogenesis and EE, controlled by central areas such as the preoptic area (POA) and the ventromedial, dorsomedial, and arcuate hypothalamic nuclei (VMH, DMH, and ARC). The SNS also regulates lipid metabolism in WAT, controlled by the lateral hypothalamic area (LHA), VMH, and ARC. Control of hepatic glucose production and pancreatic insulin secretion also involves the LHA, VMH, and ARC as well as the dorsal vagal complex (DVC), via splanchnic sympathetic and the vagal parasympathetic nerves. Muscle glucose uptake is also controlled by the SNS via hypothalamic nuclei such as the VMH. There is recent evidence of novel pathways connecting the CNS and ANS. These include the hypothalamic AMP-activated protein kinase–SNS–BAT axis which has been demonstrated to be a key modulator of thermogenesis. In this review, we summarize current knowledge of the role of the ANS in the modulation of energy balance.

Prediabetes and associated disorders.

Abstract: Prediabetes represents an elevation of plasma glucose above the normal range but below that of clinical diabetes. Prediabetes includes individuals with IFG, IGT, IFG with IGT and elevated HbA1c levels. Insulin resistance and β-cell dysfunction are characteristic of this disorder. The diagnosis of prediabetesis is vital as both IFG and IGT are indeed well-known risk factors for type 2 diabetes with a greater risk in the presence of combined IFG and IGT. Furthermore, as will be illustrated in this review, prediabetes is associated with associated disorders typically only considered in with established diabetes. These include cardiovascular disease, periodontal disease, cognitive dysfunction, microvascular disease, blood pressure abnormalities, obstructive sleep apnea, low testosterone, metabolic syndrome, various biomarkers, fatty liver disease, and cancer. As the vast majority of individuals with prediabetes are unaware of their diagnosis, it is therefore vital that the associated conditions are identified, particularly in the presence of mild hyperglycemia, so they may benefit from early intervention.

GH and the cardiovascular system: an update on a topic at heart.

Abstract: In this review, the importance of growth hormone (GH) for the maintenance of normal cardiac function in adult life is discussed. Physiological effects of GH and underlying mechanisms for interactions between GH and insulin-like growth factor I (IGF-I) and the cardiovascular system are covered as well as the cardiac dysfunction caused both by GH excess (acromegaly) and by GH deficiency in adult hypopituitary patients. In both acromegaly and adult GH deficiency, there is also increased cardiovascular morbidity and mortality possibly linked to aberrations in GH status. Finally, the status of the GH/IGF-I system in relation to heart failure and the potential of GH as a therapeutic tool in the treatment of heart failure are reviewed in this article.

Childhood obesity affects adult metabolic syndrome and diabetes

Abstract: We seek to observe the association between childhood obesity by different measures and adult obesity, metabolic syndrome (MetS), and diabetes. Thousand two hundred and nine subjects from “Beijing Blood Pressure Cohort Study” were followed 22.9 ± 0.5 years in average from childhood to adulthood. We defined childhood obesity using body mass index (BMI) or left subscapular skinfold (LSSF), and adult obesity as BMI ≥28 kg/m2. MetS was defined according to the joint statement of International Diabetes Federation and American Heart Association with modified waist circumference (≥90/85 cm for men/women). Diabetes was defined as fasting plasma glucose ≥7.0 mmol/L or blood glucose 2 h after oral glucose tolerance test ≥11.1 mmol/L or currently using blood glucose-lowering agents. Multiple linear and logistic regression models were used to assess the association. The incidence of adult obesity was 13.4, 60.0, 48.3, and 65.1 % for children without obesity, having obesity by BMI only, by LSSF only, and by both, respectively. Compared to children without obesity, children obese by LSSF only or by both had higher risk of diabetes. After controlling for adult obesity, childhood obesity predicted independently long-term risks of diabetes (odds ratio 2.8, 95 % confidence interval 1.2–6.3) or abdominal obesity (2.7, 1.6–4.7) other than MetS as a whole (1.2, 0.6–2.4). Childhood obesity predicts long-term risk of adult diabetes, and the effect is independent of adult obesity. LSSF is better than BMI in predicting adult diabetes.

Plasma levels of SIRT1 associate with non-alcoholic fatty liver disease in obese patients

Abstract: Sirtuins (SIRTs) are master metabolic regulators with protective roles against obesity and obesity-associated metabolic disorders, including non-alcoholic fatty liver disease (NAFLD) and type-2 diabetes We aimed to ascertain whether there is a relationship between serum SIRT1 and liver steatosis severity in obese patients Seventy-two obese patients (BMI ≥ 30 kg/m2), 18 males and 54 females, mean age 3966 ± 1234 years, with ultrasonographic evidence of NAFLD, were studied BMI, transaminases, insulin, HOMA-index, HbA1c, body composition (DXA), plasma SIRT1 levels (ELISA) and representative measures of metabolic syndrome (waist circumference, fasting plasma glucose, blood pressure, HDL-cholesterol, triglycerides) and inflammation (ESR, CRP, fibrinogen) were evaluated Thirty healthy lean patients were included as controls SIRT1 was significantly lower in severe liver steatosis obese group compared to the mild steatosis group, both had lower SIRT1 plasma values compared to control lean patients (P = 00001) SIRT1 showed an inverse correlation with liver steatosis and HbA1c in univariate analysis (ρ = −0386; P = 0001; ρ = −0300; P = 001, respectively) Multiple linear regression analysis showed that liver steatosis was the independent correlate of SIRT1 even after adjustment for potentially relevant variables (β = −0442; P = 0003) Serum SIRT1 might be a novel clinical/biochemical parameter associated with fat liver infiltration Further studies in larger cohorts are warranted

Inflammation in diabetic nephropathy: moving toward clinical biomarkers and targets for treatment

Abstract: Diabetic nephropathy (DN) is a leading cause of end stage renal failure and there is an urgent need to identify new clinical biomarkers and targets for treatment to effectively prevent and slow the progression of the complication. Many lines of evidence show that inflammation is a cardinal pathogenetic mechanism in DN. Studies in animal models of experimental diabetes have demonstrated that there is a low-grade inflammation in the diabetic kidney. Both pharmacological and genetic strategies targeting inflammatory molecules have been shown to be beneficial in experimental DN. In vitro studies have cast light on the cellular mechanisms whereby diabetes triggers inflammation and in turn inflammation magnifies the kidney injury. Translation of this basic science knowledge into potential practical clinical applications is matter of great interest for researchers today. This review focuses on key pro-inflammatory systems implicated in the development of DN: the tumor necrosis factor(TNF)-α/TNF-α receptor system, the monocyte chemoattractant protein-1/CC-chemokine receptor-2 system, and the Endocannabinoid system that have been selected as they appear particularly promising for future clinical applications.

PI3K/Akt/mTOR signaling in medullary thyroid cancer: a promising molecular target for cancer therapy

Abstract: The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is a central hub for the regulation of cell proliferation, apoptosis, cell cycle, metabolism, and angiogenesis. Several studies have recently suggested that the PI3K/Akt/mTOR signaling pathway is implicated in the pathogenesis and progression of neuroendocrine tumors. Medullary thyroid cancer (MTC) is a neuroendocrine tumor developing from the C cells of the thyroid. Mutations in the RET proto-oncogene are involved in the pathogenesis of several forms of MTC. The deregulation of the PI3K/Akt/mTOR pathway seems to contribute to the tumorigenic activity of RET proto-oncogene mutations. Targeting this pathway through specific inhibitors at simple or multiple sites may represent an attractive potential therapeutic approach for patients with advanced MTCs. The aim of this review is to examine the role of the PI3K/Akt/mTOR pathway in the development and progression of MTC and the new therapeutic options that target this signaling pathway.

Nonclassic congenital adrenal hyperplasia due to 21-hydroxylase deficiency: clinical presentation, diagnosis, treatment, and outcome

Abstract: Nonclassic congenital adrenal hyperplasia (NCAH) is one of the most frequent autosomal recessive disorders in man with a prevalence ranging from 0.1 % in Caucasians up to a few percent in certain ethnic groups. Most cases are never diagnosed due to very mild symptoms, misdiagnosing as polycystic ovary syndrome, or ignorance. In contrast to classic CAH, patients with NCAH present with mild partial cortisol insufficiency and hyperandrogenism and will survive without any treatment. Undiagnosed NCAH may result in infertility, miscarriages, oligomenorrhea, hirsutism, acne, premature pubarche, testicular adrenal rest tumors, adrenal tumors, and voice problems among other symptoms. A baseline measurement of 17-hydroxyprogesterone can be used for diagnosis, but the ACTH stimulation test with measurement of 17-hydroxyprogesterone is regarded as the golden standard. The diagnosis can be verified by CYP21A2 mutation analysis. Treatment is symptomatic and usually with glucocorticoids alone. The lowest possible glucocorticoid dose should be used. Long-term treatment with glucocorticoids will improve the symptoms but will also result in iatrogenic cortisol insufficiency and may also lead to long-term complications such as obesity, insulin resistance, hypertension, osteoporosis, and fractures. Although the complications seen in NCAH patients have been assumed to be related to the glucocorticoid treatment, some may, in fact, be associated with prolonged hyperandrogenism. Different risk factors and negative consequences should be monitored regularly in an attempt to improve the clinical outcome. More research is needed in this relatively common disorder.

Uric acid induces oxidative stress via an activation of the renin–angiotensin system in 3T3-L1 adipocytes

Abstract: Hyperuricemia is recently reported involving in various obesity-related cardiovascular disorders, especially hypertension. However, the underlying mechanisms are not completely understood. In the present study, we investigated whether uric acid upregulates renin–angiotensin system (RAS) expression in adipocytes. We also examined whether RAS activation plays a role in uric acid-induced oxidative stress in adipocytes. The adipocytes of different phenotypes were incubated with uric acid for 48 h, respectively. Losartan (10−4 M) or captopril (10−4 M) was used to block adipose tissue RAS activation. mRNA expressions of angiotensinogen (AGT), angiotensin-converting enzyme-1 (ACE-1), renin, angiotensin type 1 receptor (AT1R), and angiotensin type 2 receptor (AT2R) were evaluated with real-time PCR. Angiotensin II concentrations in supernatant were measured by ELISA. Intracellular reactive species (ROS) levels were measured by fluorescent probe DCFH-DA, DHR, or NBT assay. The uric acid upregulated both RAS (AGT, ACE1, renin, AT1R, and AT2R) mRNA expressions and angiotensin II protein secretion and caused a significant increase in ROS production in 3T3-L1 adipocytes. These effects could be prevented by RAS inhibitors, either losartan or captopril. RAS activation has been causally implicated in oxidative stress induced by uric acid in 3T3-L1 adipocytes, suggesting a plausible mechanism through which hyperuricemia contributes to the pathogenesis of obesity-related cardiovascular diseases.

A four-season molecule: osteocalcin. Updates in its physiological roles

Abstract: Osteocalcin (OC) is the main non-collagenous hydroxyapatite-binding protein synthesized by osteoblasts, odontoblasts, and hypertrophic chondrocytes. It has a regulatory role in mineralization and it is considered a marker of bone cell metabolism. Recent findings evidenced new extra-skeletal roles for OC, depicting it as a real hormone. OC shares many functional features with the common hormones, such as tissue-specific expression, circadian rhythm, and synthesis as a pre-pro-molecule. However, it has some peculiar features making it a unique molecule: OC exists in different forms based on the degree of carboxylation. Indeed, OC has three glutamic acid residues, in position 17, 21, and 24, which are subject to γ-carboxylation, through the action of a vitamin K-dependent γ-glutamyl carboxytransferase. The degree of carboxylation, and thus the negative charge density, determines the affinity for the calcium ions deposited in the extracellular matrix of the bone. The modulation of the carboxylation could, thus, represent the mechanism by which the body controls the circulating levels, and hence the hormonal function, of OC. There are evidences linking OC, and the bone metabolism, with a series of endocrine (glucose metabolism, energy metabolism, fertility) physiological (muscle activity) and pathological functions (ectopic calcification). Aim of this review is to give a full overview of the physiological roles of OC by collecting the newest experimental findings on this intriguing molecule.

Dihydromyricetin improves skeletal muscle insulin sensitivity by inducing autophagy via the AMPK-PGC-1α-Sirt3 signaling pathway

Abstract: Insulin resistance in skeletal muscle is a key feature in the pathogenesis of type 2 diabetes (T2D) that often manifests early in its development. Pharmaceutical and dietary strategies have targeted insulin resistance to control T2D, and many natural products with excellent pharmacological properties are good candidates for the control or prevention of T2D. Dihydromyricetin (DHM) is a natural flavonol which provides a wide range of health benefits including anti-inflammatory and anti-tumor effects. However, little information is available regarding the effects of DHM on skeletal muscle insulin sensitivity as well as the underlying mechanisms. In the present study, we found that DHM activated insulin signaling and increased glucose uptake in skeletal muscle in vitro and in vivo. The expression of light chain 3, the degradation of sequestosome 1, and the formation of autophagosomes were also upregulated by DHM. DHM-induced insulin sensitivity improvement was significantly abolished in the presence of 3-methyladenine, bafilomycin A1, or Atg5 siRNA in C2C12 myotubes. Furthermore, DHM increased the levels of phosphorylated AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor coactivator-1α (PGC-1α), and Sirt3 in skeletal muscle in vitro and in vivo. Autophagy was inhibited in the presence of Sirt3 siRNA in C2C12 myotubes and in skeletal muscles from Sirt3−/− mice. Additionally, PGC-1α or AMPK siRNA transfection attenuated DHM-induced Sirt3 expression, thereby abrogating DHM-induced autophagy in C2C12 myotubes. In conclusion, DHM improved skeletal muscle insulin sensitivity by partially inducing autophagy via activation of the AMPK-PGC-1α-Sirt3 signaling pathway.

Diabetes mellitus and oral health

Abstract: The oral health is influenced by systemic health, and one of the most common chronic diseases encountered in dental practice is diabetes mellitus. Diabetes can worsen oral infections and vice versa. In the literature, periodontitis and diabetes in the young to middle-aged adults have been the most widely researched area. Understanding the patho-physiology, clinical manifestations and management of different types of orofacial diseases in diabetic patients are important to the diabetologist and the dentist for the optimal care of patients with these diseases. This review explores the inter-link between diabetes and oral health.

Down-regulation of miR-144 promotes thyroid cancer cell invasion by targeting ZEB1 and ZEB2.

Abstract: Thyroid cancer is the most common endocrine malignancy, and its incidence has increased rapidly worldwide. The molecular mechanisms underlying thyroid cancer tumorigenesis still need to be further investigated. MicroRNAs (miRNAs), short RNA molecules of approximately 22 nucleotides in length, play crucial roles in tumorigenesis. In the present study, we found that the expression of miR-144 was significantly down-regulated in thyroid cancer as compared with that in normal thyroid tissues, suggesting that miR-144 may be involved in thyroid cancer tumorigenesis. Moreover, our results showed that restoration of miR-144 in K1 and WRO thyroid cancer cells could suppress the invasion and migration capability of these cells. We also demonstrated that miR-144 suppressed the expression of ZEB1 and ZEB2, two E-cadherin suppressors, by directly binding to their 3'-untranslated regions. Furthermore, restoration of ZEB1 or ZEB2 partially rescued the miR-144-induced inhibition of cell invasion. These data suggest miR-144 function as a tumor suppressor in thyroid cancer.

Growth hormone tumor histological subtypes predict response to surgical and medical therapy.

Abstract: Growth hormone (GH) pituitary tumors are associated with significant morbidity and mortality. Current treatments, including surgery and medical therapy with somatostatin analogs (SSA), dopamine agonists and/or a GH receptor antagonist, result in disease remission in approximately half of patients. Predictors of GH tumor response to different therapies have been incompletely defined based on histologic subtype, particularly densely (DG) versus sparsely (SG) granulated adenomas. The aim of this study was to examine our own institutional experience with GH adenomas and correlate how subtype related to clinical parameters as well as response to surgery and medical therapies. A retrospective chart review of 101 acromegalic patients operated by a single neurosurgeon was performed. Clinical data were correlated with histologic subtype and disease control, as defined by IGF-1 levels, and random growth hormone levels in response to surgery and/or medical therapies. SG tumors, compared to DG, occurred in younger patients (p = 0.0010), were 3-fold larger (p = 0.0030) but showed no differences in tumor-invasion characteristics (p = 0.12). DG tumors had a higher rate of remission in response to surgery compared to SG, 65.7 vs. 14.3 % (p < 0.0001), as well as to medical therapy with SSAs (68.8 % for DG vs. 28.6 % for SG tumors; p = 0.028). SG tumors not controlled with SSAs consistently responded to a switch to, or addition of, a GH receptor antagonist. Histological GH tumor subtyping implicates a different clinical phenotype and biologic behavior, and provides prognostic significance for surgical success and response to medical therapies.

Biochemical and genetic diagnosis of 21-hydroxylase deficiency

Abstract: Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is caused by mutations in the CYP21A2 gene and is often fatal in its classic forms if not treated with glucocorticoids In contrast, non-classic CAH (NCCAH), with a prevalence from 01 % up to a few percentages in certain ethnic groups, only results in mild partial cortisol insufficiency and patients survive without treatment Most NCCAH cases are never identified, but unnecessary suffering due to hyperandrogenism, especially in females, can be avoided by a correct diagnosis A 17-hydroprogesterone (17OHP) level above 300 nmol/L indicates classic CAH while 30–300 nmol/L in adult males or females (follicular phase or if anovulatoric) indicates NCCAH The gold standard for diagnosing NCCAH is the ACTH stimulation test Deletion, large gene conversions, and nine microconversion-derived mutations are the most common CYP21A2 mutations However, almost 200 rare mutations have been described Since there is a good genotype–phenotype relationship, genotyping provides valuable diagnostic, as well as prognostic information Neonatal screening for CAH is now performed in an increasing number of countries with the main goal of reducing mortality and morbidity due to salt-losing adrenal crises in the newborn period In addition, screening may shorten the time to diagnosis in virilized girls Neonatal screening misses some patients with milder classic CAH and most NCCAH cases In conclusion, diagnosing classic CAH is life-saving, but diagnosing NCCAH is also important to prevent unnecessary suffering

Does microbiota composition affect thyroid homeostasis

Abstract: The intestinal microbiota is essential for the host to ensure digestive and immunologic homeostasis. When microbiota homeostasis is impaired and dysbiosis occurs, the malfunction of epithelial barrier leads to intestinal and systemic disorders, chiefly immunologic and metabolic. The role of the intestinal tract is crucial in the metabolism of nutrients, drugs, and hormones, including exogenous and endogenous iodothyronines as well as micronutrients involved in thyroid homeostasis. However, the link between thyroid homeostasis and microbiota composition is not yet completely ascertained. A pathogenetic link with dysbiosis has been described in different autoimmune disorders but not yet fully elucidated in autoimmune thyroid disease which represents the most frequent of them. Anyway, it has been suggested that intestinal dysbiosis may trigger autoimmune thyroiditis. Furthermore, hypo- and hyper-thyroidism, often of autoimmune origin, were respectively associated to small intestinal bacterial overgrowth and to changes in microbiota composition. Whether some steps of this thyroid network may be affected by intestinal microbiota composition is briefly discussed below.

Adipogenic changes of hepatocytes in a high-fat diet-induced fatty liver mice model and non-alcoholic fatty liver disease patients.

Abstract: Non-alcoholic fatty liver disease (NAFLD) is characterized by steatosis associated with liver inflammation. As NAFLD progresses, triglycerides increase within hepatocytes, causing typical vacuoles that resemble adipocytes. However, whether these morphological changes in hepatocytes indicate potential functional changes is unclear. C57BL/6J mice were fed a high-fat diet (HFD) containing 42 % fat. Markers for adipocytes in the liver were measured using real-time PCR, Western blot, and double immunofluorescent labeling. Cytokines in cell culture supernatants were quantified with ELISA. To determine the macrophage phenotype, hepatic classical M1 markers and alternative M2 markers were analyzed. After a 24-week feeding period, adipocyte markers aP2 and PPARγ increased at both the mRNA and protein level in the liver of HFD-fed mice. FITC-labeled aP2 and rhodamine-labeled albumin were both stained in the cytoplasm of steatotic hepatocytes as observed under confocal laser scanning microscopy. Cell membrane-bound E-cadherin and albumin expression were reduced in steatotic hepatocytes compared to controls. However, hepatic adiponectin and adiponectin receptor-2 expression decreased with upregulation of hepatic CD36, suggesting impaired adiponectin activity in livers of HFD-fed mice. Moreover, steatotic primary hepatocytes not only released pro-inflammatory cytokines such as TNFα, MCP-1, IL-6, and IL-18, but also could activate macrophages when co-cultured in vitro. In vivo, hepatic expression of M1 genes such as iNOS and TNFα was markedly increased in HFD-fed mice. In contrast, hepatic expression of M2 genes such as Arg1 and CD206 was significantly reduced. Specifically, the ratio of TNFα to CD206 in HFD-fed mice was notably upregulated. Overexpression of adipocyte-specific genes in hepatocytes and their secretory function and epithelial phenotype impairment in NAFLD cause functional changes in steatotic hepatocytes aside from morphological changes. This suggests that adipogenic changes in hepatocytes are involved in pathogenesis of NAFLD.

Determinants of testosterone levels in human male obesity

Abstract: Testosterone (T) levels are decreased in obese men, but the underlying causes are incompletely understood. Our objective was to explore the relation between low (free) T levels and male obesity, by evaluating metabolic parameters, subcutaneous adipose tissue (SAT) aromatase expression, and parameters of the hypothalamic–pituitary–gonadal axis. We recruited 57 morbidly obese men [33 had type 2 diabetes (DM2)] and 25 normal-weight men undergoing abdominal surgery. Fourteen obese men also attended a follow-up, 2 years after gastric bypass surgery (GBS). Circulating T levels were quantified by LC–MS/MS, whereas free T levels were measured using serum equilibrium dialysis and sex hormone-binding globulin, luteinizing hormone, and follicle-stimulating hormone by immunoassay. SAT biopsies were used to determine adipocyte cell size and aromatase expression by real-time PCR. Total and free T levels were decreased in obese males versus controls, with a further decrease in obese men with DM2 versus obese men without DM2. There were no differences in aromatase expression among the study groups, and sex steroids did not correlate with aromatase expression. Pearson analysis revealed an inverse association between (free) T and SAT cell size, triglycerides, and HOMA-IR. Multivariate analysis confirmed the inverse association between (free) T and SAT cell size (β = −0.321, P = 0.037 and β = −0.441, P = 0.011, respectively), independent of age, triglycerides, HOMA-IR, obesity, or diabetes. T levels were normalized 2 years after GBS. These data suggest that SAT cell size rather than SAT aromatase expression or parameters of the hypothalamic–pituitary–gonadal axis is related to low T in male obesity, which points to adipose cell size-related metabolic changes as a major trigger in decreased T levels.

Elevated ratio of acylated to unacylated ghrelin in children and young adults with Prader–Willi syndrome

Abstract: Prader–Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. Hyperghrelinemia may be involved in the underlying mechanisms of the switch. The purpose of this study is to evaluate acylated ghrelin (AG) and unacylated ghrelin (UAG) levels in PWS and investigate their associations with hyperphagia. This is a cross-sectional clinical study conducted in three PWS expert centers in the Netherlands and France. Levels of AG and UAG and the AG/UAG ratio were determined in 138 patients with PWS (0.2–29.4 years) and compared with 50 age-matched obese subjects (4.3–16.9 years) and 39 healthy controls (0.8–28.6 years). AEBSF was used to inhibit deacylation of AG. As a group, PWS patients had higher AG but similar UAG levels as healthy controls (AG 129.1 vs 82.4 pg/ml, p = 0.016; UAG 135.3 vs 157.3 pg/ml, resp.), resulting in a significantly higher AG/UAG ratio (1.00 vs 0.61, p = 0.001, resp.). Obese subjects had significantly lower AG and UAG levels than PWS and controls (40.3 and 35.3 pg/ml, resp.), but also a high AG/UAG ratio (1.16). The reason for the higher AG/UAG ratio in PWS and obese was, however, completely different, as PWS had a high AG and obese a very low UAG. PWS patients without weight gain or hyperphagia had a similar AG/UAG ratio as age-matched controls, in contrast to those with weight gain and/or hyperphagia who had an elevated AG/UAG ratio. The switch to excessive weight gain in PWS seems to coincide with an increase in the AG/UAG ratio, even prior to the start of hyperphagia.

Identification of a novel germline FOXE1 variant in patients with familial non-medullary thyroid carcinoma (FNMTC)

Abstract: The familial forms of non-medullary thyroid carcinoma (FNMTC) represent approximately 5 % of thyroid neoplasms. Nine FNMTC susceptibility loci have been mapped; however, only the DICER1 and SRGAP1 susceptibility genes have been identified. The transcription factors NKX2-1, FOXE1, PAX8, and HHEX are involved in the morphogenesis and differentiation of the thyroid. Recent studies have identified NKX2-1 germline mutations in FNMTC families. However, the role of high-penetrant FOXE1 variants in FNMTC etiology remains unclear. The aim of this study was to investigate the role of FOXE1 germline mutations in the pathogenesis of FNMTC. We searched for molecular changes in the FOXE1 gene in the probands from 60 Portuguese families with FNMTC. In this series, we identified nine polymorphisms and one variant (c.743C>G, p.A248G) which was not previously described. This variant, which involved an amino acid residue conserved in evolution, segregated with disease in one family, and was also detected in an apparently unrelated case of sporadic NMTC. Functional studies were performed using rat normal thyroid cells (PCCL3) clones and human papillary thyroid carcinoma cell line (TPC-1) pools, expressing the wild type and mutant (p.A248G) forms of FOXE1. In these experiments, we observed that the p.A248G variant promoted cell proliferation and migration, suggesting that it may be involved in thyroid tumorigenesis. Additionally, somatic p.V600E BRAF mutations were also detected in the thyroid tumors of two members of the family carrying the p.A248G variant. This study represents the first evidence of involvement of a germline FOXE1 rare variant in FNMTC etiology and suggests that mutations in MAPK pathway-related genes may contribute to tumor development in these familial cases.

Incretin-based therapies and acute pancreatitis risk: a systematic review and meta-analysis of observational studies

Abstract: Concerns raised by several animal studies, case reports, and pharmacovigilance warnings over incretin-based therapy potentially exposing type two diabetes patients to an elevated risk of pancreatitis have cast a shadow on the overall safety of this class of drugs. This systematic review evaluates the data from observational studies that compared treatment with or without incretins and the risk of pancreatitis. We searched PubMed for publications with the key terms incretins or GLP-1 receptor agonists or DPP-4 inhibitors or sitagliptin or vildagliptin or saxagliptin or linagliptin or alogliptin or exenatide or liraglutide AND pancreatitis in the title or abstract. Studies were evaluated against the following criteria: design (either cohort or case–control); outcome definition (incidence of pancreatitis); exposure definition (new or current or past incretins users); and comparison between patients receiving incretins or not for type 2 diabetes. Two authors independently selected the studies and extracted the data. Six studies meeting the inclusion criteria were reviewed. No difference was found in the overall risk of pancreatitis between incretin users and non-users (odds ratio 1.08; 95 % CI [0.84–1.40]). A risk increase lower than 35 % cannot be excluded according to the power calculation. This systematic review and meta-analysis suggests that type 2 diabetes patients receiving incretin-based therapy are not exposed to an elevated risk of pancreatitis. Limitations of this analysis are the low prevalence of incretin users and the lack of a clear distinction by the studies between therapy with DPP-4 inhibitors or with GLP-1 receptor agonists.

One-year treatment with liraglutide improved renal function in patients with type 2 diabetes: a pilot prospective study

Abstract: Unlike GLP-1, liraglutide is not cleared by the glomerulus and its pharmacokinetic is not altered in patients with mild renal impairment. The aim of our study was to analyze the effects of liraglutide on renal function in patients with type 2 diabetes. A twelve-month longitudinal prospective post-marketing study was performed. According to eGFR (estimated glomerular filtration rate) calculated with CKD-EPI equation, 84 consecutive patients were divided in Group A (eGFR > 90 ml/min) and Group B (eGFR 90 ml/min). At baseline, five patients had pathological microalbuminuria, but at 12 months three of them returned to normal albuminuria (p < 0.006). Total microalbuminuria levels improved in both groups (p < 0.02). According to preliminary data in animals, our study shows that liraglutide is effective in preserving eGFR in diabetic patients, increasing it in those with reduced renal function. This was associated with a decrease of frequency of patients positive to microalbuminuria. Further studies are needed to confirm these data.

Prospective population-based study of the association between vitamin D status and incidence of autoimmune disease

Abstract: Beside its traditional role in skeletal health, vitamin D is believed to have multiple immunosuppressant properties, and low vitamin D status has been suggested to be a risk factor in the development of autoimmune disease. We investigated the association between vitamin D status and development of autoimmune disease. We included a total of 12,555 individuals from three population-based studies with measurements of vitamin D status (25-hydroxy vitamin D). We followed the participants by linkage to the Danish National Patient Register (median follow-up time 10.8 years). Relative risks of autoimmune disease were estimated by Cox regression and expressed as hazard ratios, HRs (95 % confidence intervals CIs). There were 525 cases of incident autoimmune disease. The risk for a 10 nmol/l higher vitamin D was: for any autoimmune disease (HR = 0.94 % CI 0.90, 0.98); thyrotoxicosis (HR = 0.83, 95 % CI 0.72, 0.96); type 1 diabetes (HR = 0.95, 95 % CI 0.88, 1.02), multiple sclerosis (HR = 0.89, 95 % CI 0.74, 1.07), iridocyclitis (HR = 1.00, 95 % CI 0.86, 1.17); Crohn’s disease (HR = 0.95, 95 % CI 0.80, 1.13), ulcerative colitis (HR = 0.88, 95 % CI 0.75, 1.04); psoriasis vulgaris (HR = 0.99, 95 % CI 0.86, 1.13); seropositive rheumatoid arthritis (HR = 0.97, 95 % CI 0.89, 1.07), and polymyalgia rheumatica (HR = 0.94, 95 % CI 0.83, 1.06). We found statistically significant inverse associations between vitamin D status and development of any autoimmune disease and thyrotoxicosis in particular. Our findings suggest a possible protective role of a higher vitamin D status on autoimmune disease but warrant further studies to clarify causality.

The association between diabetes and depression: a very disabling condition.

Abstract: Rates of depression are significantly increased in diabetic patients, and even more in the elderly. About 20-30% of patients with diabetes suffer from clinically relevant depressive disorders, 10% of which being affected by the major depression disorder. Moreover, people with depression seem to be more prone to develop an associated diabetes mellitus, and depression can worsen glycemic control in diabetes, with higher risk to develop complications and adverse outcomes, whereas improving depressive symptoms is generally associated with a better glycemic control. Thus, the coexistence of depression and diabetes has a negative impact on both lifestyle and quality of life, with a reduction of physical activity and an increase in the request for medical care and prescriptions, possibly increasing the healthcare costs and the susceptibility to further diseases. These negative aspects are particularly evident in the elderly, with further decrease in the mobility, worsening of disability, frailty, geriatric syndromes and increased mortality. Healthcare providers should be aware of the possible coexistence of depression and diabetes and of the related consequences, to better manage the patients affected by these two pathological conditions.

Insights into the molecular mechanisms of diabetes-induced endothelial dysfunction: focus on oxidative stress and endothelial progenitor cells

Abstract: Diabetes mellitus is a heterogeneous, multifactorial, chronic disease characterized by hyperglycemia owing to insulin insufficiency and insulin resistance (IR). Recent epidemiological studies showed that the diabetes epidemic affects 382 million people worldwide in 2013, and this figure is expected to be 600 million people by 2035. Diabetes is associated with microvascular and macrovascular complications resulting in accelerated endothelial dysfunction (ED), atherosclerosis, and cardiovascular disease (CVD). Unfortunately, the complex pathophysiology of diabetic cardiovascular damage is not fully understood. Therefore, there is a clear need to better understand the molecular pathophysiology of ED in diabetes, and consequently, better treatment options and novel efficacious therapies could be identified. In the light of recent extensive research, we re-investigate the association between diabetes-associated metabolic disturbances (IR, subclinical inflammation, dyslipidemia, hyperglycemia, dysregulated production of adipokines, defective incretin and gut hormones production/action, and oxidative stress) and ED, focusing on oxidative stress and endothelial progenitor cells (EPCs). In addition, we re-emphasize that oxidative stress is the final common pathway that transduces signals from other conditions-either directly or indirectly-leading to ED and CVD.

PDE5 expression in human thyroid tumors and effects of PDE5 inhibitors on growth and migration of cancer cells.

Abstract: Recent studies have revealed in normal thyroid tissue the presence of the transcript of several phosphodiesterases (PDEs), enzymes responsible for the hydrolysis of cyclic nucleotides. In this work, we analyzed the expression of PDE5 in a series of human papillary thyroid carcinomas (PTCs) presenting or not BRAF V600E mutation and classified according to ATA risk criteria. Furthermore, we tested the effects of two PDE5 inhibitors (sildenafil, tadalafil) against human thyroid cancer cells. PDE5 gene and protein expression were analyzed in two different cohorts of PTCs by real-time PCR using a TaqMan micro-fluid card system and Western blot. MTT and migration assay were used to evaluate the effects of PDE5 inhibitors on proliferation and migration of TPC-1, BCPAP, and 8505C cells. In a first series of 36 PTCs, we found higher expression levels of PDE5A in tumors versus non-tumor (normal) tissues. PTCs with BRAF mutation showed higher levels of mRNA compared with those without mutation. No significant differences were detected between subgroups with low and intermediate ATA risk. Upregulation of PDE5 was also detected in tumor tissue proteins. Similar results were obtained analyzing the second cohort of 50 PTCs. Moreover, all tumor tissues with high PDE5 levels showed reduction of Thyroglobulin, TSH receptor, Thyroperoxidase, and NIS transcripts. In thyroid cancer cells in vitro, sildenafil and tadalafil determined a reduction of proliferation and cellular migration. Our findings demonstrate for the first time an overexpression of PDE5 in PTCs, and the ability of PDE5 inhibitors to block the proliferation of thyroid cancer cells in culture, therefore, suggesting that specific inhibition of PDE5 may be proposed for the treatment of these tumors.

Thyroxine softgel capsule in patients with gastric-related T4 malabsorption.

Abstract: The key role of an intact gastric acid secretion for subsequent intestinal T4 absorption is supported by an increased requirement of thyroxine in patients with gastric disorders. A better pH-related dissolution profile has been described in vitro for softgel T4 preparation than for T4 tablets. Our study was aimed at comparing softgel and tablet T4 requirements in patients with gastric disorders. A total of 37 patients with gastric-related T4 malabsorption were enrolled, but only 31 (28F/3M; median age = 50 years; median T4 dose = 2.04 μg/kg/day) completed the study. All patients were in long-lasting treatment (>2 years) with the same dose of T4 tablets when treatment was switched to a lower dose of softgel T4 capsules (−17 %; p = 0.0002). Assessment of serum FT4 and TSH was carried out at baseline and after 3, 6, 12, and 18 months after the treatment switch. In more than 2/3 of patients (good-responders n = 21), despite the reduced dose of T4, median TSH values were similar at each time point (p = 0.3934) with no change in FT4 levels. In the remaining patients (poor-responders n = 10), TSH levels were significantly higher at each time point than at baseline (p < 0.0001). To note, in five of them intestinal comorbidity was subsequently detected. Comorbidity associated with poor-responders status was the only significant predictor in multivariate analysis (OR = 11.333). Doses of softgel T4 capsules lower than T4 tablet preparation are required to maintain the therapeutic goal in 2/3 of patients with impaired gastric acid secretion.