Effect of dual glucose-dependent insulinotropic peptide/glucagon-like peptide-1 receptor agonist on weight loss in subjects with obesity.

The occurrence of obesity is an increasing issue worldwide, especially in industrialized countries. Weight loss is important both to treat obesity and to prevent the development of complications. Currently, several drugs are used to treat obesity, but their efficacy is modest. Thus, new anti-obesity treatments are needed. Recently, there has been increased interest in the development of incretins that combine body-weight-lowering and glucose-lowering effects. Therefore, a new drug that simultaneously coactivates both the glucose-dependent insulinotropic polypeptide (GIP) receptor (GIPR) and the glucagon-like peptide-1 receptor (GLP-1R) has been developed. Tirzepatide, the first in this class, improves glycemic control by increasing insulin sensitivity and lipid metabolism as well as by reducing body weight. Combining the activation of the two receptors, greater improvement of ß-cell function offers more effective treatment of diabetes and obesity with fewer adverse effects than selective GLP-1R agonists. In the present review, we discuss the progress in the use of GIPR and GLP-1R coagonists and review literature from in vitro studies, animal studies, and human trials, highlighting the synergistic mechanisms of tirzepatide.

Immuno-Mediated Inflammation in Hypertensive Patients with 1-h Post-Load Hyperglycemia.

Inflammation plays a key role in the pathogenesis/progression of atherosclerosis, and inflammatory molecules contribute to the progression of cardiovascular disease. Subjects with normal post-load glucose tolerance and 1-h post-load plasma glucose >155 mg/dL have an increased risk of subclinical target organ damage and incident diabetes. We aimed to test possible differences in immune-mediated inflammatory parameters in newly-diagnosed hypertensives with or without 1-h post-load hyperglycemia. We enrolled 25 normotensives (NGT) and 50 hypertensives normotolerant on oral glucose tolerance test, further divided into two groups based on 1-h post-load plasma glucose: NGT 1-h ≥ 155 (n = 25) and NGT 1-h < 155 (n = 25). We measured toll-like receptor (TLR) 2, TLR4, nuclear factor kß (NF-kß), interleukin (IL)-1ß, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-α. Hypertensives showed significantly worse metabolic and lipid profiles, and higher values of body mass ass index (BMI), creatinine, and inflammatory parameters, compared to controls. NGT 1-h ≥ 155 had a worse glycometabolic profile and higher values of TLR2 (9.4 ± 4.2 vs. 5.9 ± 2.6 MFI), TLR4 (13.1 ± 3.9 vs. 7.8 ± 2.3 MFI), NF-kß (0.21 ± 0.07 vs. 0.14 ± 0.04), IL-1ß (6.9 ± 3.4 vs. 3.2 ± 2.1 pg/mL), IL-6 (10.8 ± 2.6 vs. 4.1 ± 1.6 pg/mL), IL-8 (27.6 ± 9.3 vs. 13.3 ± 5.6 pg/mL), TNF-α (6.4 ± 2.9 vs. 3.3 ± 1.4 pg/mL), and high-sensitivity C-reactive protein (hs-CRP) (4.8 ± 1.5 vs. 2.7 ± 1.0 mg/dL) in comparison with NGT 1-h < 155. Matsuda-index and 1-h post-load glycemia were retained as major predictors of TLRs and NF-kß. These results contribute to better characterizing cardiovascular risk in hypertensives.

Effects of sacubitril/valsartan on both metabolic parameters and insulin resistance in prediabetic non-obese patients with heart failure and reduced ejection fraction.

Background: The effects of sacubitril/valsartan (sac/val) on metabolic parameters and insulin resistance (IR) in non-obese/prediabetic patients have not been previously described. Aim: To evaluate the effects of sac/val on glycemic and metabolic parameters, Homeostatic Model Assessment of IR (HOMA-IR), and echocardiographic parameters in prediabetic patients with heart failure with reduced ejection fraction (HFrEF). Methods: Fifty-nine patients with HFrEF (EF < 35%) but without obesity and/or type 2 diabetes mellitus have been enrolled. All the patients at baseline and week 24 underwent complete anthropometrical evaluation and were subjected to an echocardiogram test. IR has been assessed by HOMA-IR. Results: After 24-week of treatment with sac/val, a significant reduction in fasting plasma glucose (109 ± 9 vs 103 ± 8 mg/dl, p < 0.0001), fasting plasma insulin (16 ± 4 vs 10 ± 4 UI/L), and hemoglobin A1c (HbA1c) value (6% ± 0.5% vs 5.3% ± 0.3%, p < 0.0001) was observed. Similarly, we observed a significant improvement in IR (HOMA-IR, 4.4 ± 0.9 vs 2.5 ± 0.6, p < 0.0001). The echocardiogram evaluation showed a significant reduction of the left ventricular end-diastolic volume (168 ± 24 vs 158 ± 22 ml, p < 0.05), a significant reduction of the left ventricular end-systolic volume (111 ± 26 vs 98 ± 22 ml, p < 0.005), and a significant reduction of E/e' ratio. Sac/val use was also associated with an average 5.1% increase in ejection fraction. Conclusions: Our data seem to indicate that sal/val enhances metabolic control and improves insulin resistance also in prediabetic non-obese patients with HFrEF.

Long Term Metabolic Effects of Sacubitril/Valsartan in Non-Diabetic and Diabetic Patients With Heart Failure Reduced Ejection Fraction: A Real Life Study.

Sacubitril/Valsartan (sac/val) has improved clinical prognosis in patients affected by heart failure (HF) with reduced ejection fraction (HFrEF). HF and type 2 diabetes mellitus (T2DM) frequently coexist, with a prevalence of T2DM of 35%-40% in patients with HF. T2DM is the third co-morbidities in patients with HF and a strong independent risk factor for the progression of HF. In a post hoc analysis of PARADIGM-HF, improved glycemic control was shown in patients with T2DM and HFrEF receiving sac/val compared to enalapril at 12 months of follow-up. The aim of the present study was to evaluate, in a series of repeated observations in 90 HFrEF patients, the long term effect of sac/val treatment on renal function, glycometabolic state and insulin sensitivity parameters, according to diabetic status. We studied 90 patients (74 men and 16 women, mean age 68 ± 10 years, 60 diabetics and 30 non-diabetics) suffering from HFrEF and still symptomatic despite optimal pharmacological therapy. Patients with left ventricular ejection fraction (LVEF) <35% and II-III NYHA functional class were enrolled. All patients underwent clinical-instrumental and laboratory determinations and Minnesota Living with HF Questionnaire (MLHFQ) every 6 months until 30 months to evaluate benefits and adverse events. After 30 months follow-up, we observed a significant improvement in glycometabolic parameters including HbA1c, fasting glucose and insulin, insulin-like growth factor-1 (IGF-1), HOMA index, and LDL cholesterol. Moreover, renal function, NTpro-BNP levels and echocardiographic parameters significantly improved. In diabetic patients a significant reduction in use of oral antidiabetic drugs and insulin was observed after 30 months of sac/val treatment. In the whole population, multivariate analysis shows that the evolution of cardiac index (CI) was significantly associated to simultaneous changes in HOMA, IGF-1 and visit; per each visit and for 1 ng/ml increase in IGF-1 there was an increase in CI of 64.77 ml/min/m2 (p < 0.0001) and 0.98 ml/min/m2 (p = 0.003), respectively, whereas 1 point increase in HOMA was associated with a -7.33 ml/min/m2 (p = 0.003) reduction in CI. The present data confirm persistent metabolic improvement in patients with HFrEF after treatment with sac/val and highlights its potential therapeutical role in patients with metabolic comorbidities.

An open-label trial on the efficacy and tolerability of naltrexone/bupropion SR for treating altered eating behaviours and weight loss in binge eating disorder.

PURPOSE: Binge eating disorder (BED) has a considerable clinical relevance by virtue of its high numerous psychiatric and medical comorbidities; among the latter, the most frequent is obesity. Available treatments for BED have shown frequent relapse of binges or weight regain in the long term. The new combination of naltrexone and bupropion sustained release (NB) has proved to be effective for weight loss among obese patients. As NB acts on hypothalamic and reward circuits, that seem involved in the pathogenesis and maintenance of BED symptoms, this study aims to evaluate the efficacy of NB in improving pathological eating behavior and losing weight in BED patients. METHODS: In this preliminary study, 23 obese-BED patients and a control group of 20 obese non-BED patients (respectively, Groups 1 and 2) who had previously undergone at least 5 unsuccessful weight-loss programs were treated with NB in addition to modified life style. Evaluation at t0 and after 16 weeks of treatment (t1) included anthropometric measurement, eating behavior assessment and psychopathological questionnaires (EDE-Q, BES, YFAS, BDI and STAI). RESULTS: A significant and similar weight loss (ΔBMI% ≈ 8%) was evident for both groups. Pathological eating behavior (i.e., binge, grazing, emotional eating, craving for carbohydrates, and post-dinner eating), BES score and YFAS severity significantly improved, especially among BED. NB was well tolerated and drop-out rate was low. CONCLUSION: Treatment with NB, in addition to a reduced-calorie diet and increased physical activity, seems an effective and well-tolerated option for improving pathological eating behavior and losing weight in obese-BED patients. LEVEL OF EVIDENCE: Level III case-control study.

Role of a Dual Glucose-Dependent Insulinotropic Peptide (GIP)/Glucagon-like Peptide-1 Receptor Agonist (Twincretin) in Glycemic Control: From Pathophysiology to Treatment.

Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are two gut hormones, defined incretins, responsible for the amplification of insulin secretion after oral glucose intake. Unlike GLP-1, GIP has little acute effect on insulin secretion and no effect on food intake; instead it seems that the GIP may be an obesity-promoting hormone. In patients with type2 diabetes mellitus (T2DM) some studies found a downregulation of GIP receptors on pancreatic ß cells caused by hyperglycemic state, but the glucagonotropic effect persisted. Agonists of the receptor for the GLP-1 have proven successful for the treatment of diabetes, since they reduce the risk for cardiovascular and renal events, but the possible application of GIP as therapy for T2DM is discussed. Moreover, the latest evidence showed a synergetic effect when GIP was combined with GLP-1 in monomolecular co-agonists. In fact, compared with the separate infusion of each hormone, the combination increased both insulin response and glucagonostatic response. In accordance with theseconsiderations, a dual GIP/GLP-1receptor agonist, i.e., Tirzepatide, known as a "twincretin" had been developed. In the pre-clinical trials, as well as Phase 1-3 clinical trials, Tirzepatideshowedpotent glucose lowering and weight loss effects within an acceptable safety.

Serum IgG2 levels are specifically associated with whole-body insulin-mediated glucose disposal in non-diabetic offspring of type 2 diabetic individuals: a cross-sectional study.

Preclinical studies suggested that IgG2c isotype may specifically impair skeletal muscle insulin sensitivity in mice. In this study we investigated the association between serum levels of the four IgG subclasses and insulin sensitivity in non-diabetic individuals. Total IgG, IgG1, IgG2, IgG3 and IgG4 levels were measured in 262 subjects. Whole-body insulin sensitivity was assessed by euglycemic hyperinsulinemic clamp. IgG2 levels were positively correlated with BMI, waist circumference, 2-h post-load glucose levels and complement C3. Serum IgG2, but not IgG1, IgG3 and IgG4 levels were negatively correlated with whole-body insulin sensitivity (r = -0.17; P = 0.003) and muscle insulin sensitivity index (r = -0.16; P = 0.03) after adjustment for age and gender. No significant correlation was found between IgG2 levels and hepatic insulin resistance assessed by HOMA-IR and liver IR index. In a multivariable regression analysis including variables known to affect insulin sensitivity such as age, gender, BMI, smoking, lipids, inflammatory markers, fasting and 2-h post-load glucose levels, IgG2 levels were independently associated with insulin-stimulated glucose disposal (ß = -0.115, 95% CI: -0.541 to -0.024; P = 0.03). These data demonstrate the independent association between higher levels of IgG2 and decreased whole-body insulin sensitivity, thus confirming in humans the animal-based evidence indicating the pathogenic role of IgG2 in insulin resistance.

Insulin-Sensiting Effects of Tumor Necrosis Factor Alpha Inhibitors in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis.

BACKGROUND: Rheumatoid Arthritis (RA) has been associated with insulin resistance (IR), a well-established pathophysiological feature of Type 2 Diabetes (T2DM). Inconsistent literature evidence suggests that IR could be ameliorated by biological medications targeting TNFα. OBJECTIVE: The aim of this systematic review was to evaluate the effect of TNFα inhibitors (TNFi) on IR in RA patients. METHODS: We performed a systematic review in order to identify the available data on the effect of anti- TNFα medications on IR in RA patients. For this purpose, MedLine (via PubMed), Cochrane Central Register of Controlled Trials (CENTRAL) and SCOPUS were searched up to December 2016. RESULTS: The search strategy retrieved 209 individual records. Of these, only 12 articles were included in the systematic review. The pooled analysis under a random-effects model demonstrated a significant improvement of IR after treatment with TNFi quantified with the HOmeostasis Model Assessment of Insulin Resistance (HOMA-IR), with a standardized difference in means (SDM) of -0.847 (95%CI: -1.278 - 0.417, p < 0.0001). Heterogeneity across studies was high (Q = 65.00 with df = 9, p < 0.001, I2 = 89.15%). CONCLUSION: Our meta-analysis suggests that TNFα blockade might improve IR in RA patients.

Innate immunity in cardiac myxomas and its pathological and clinical correlations.

Cardiac myxomas are the most common benign cardiac tumor. We investigated the immunohistochemical properties of 11 surgically excised cardiac myxomas, in order to analyze the correlation between macrophages and mast cell populations and clinical parameters. CD68+/CD163-/iNOS- (M0) cells represent the most abundant macrophage phenotype; however, CD68+/CD163+ cells (M2) were also frequent. CD68+/iNOS+ (M1) elements were rare. Mast cells, defined as a population of c-kit (CD117)+ and/or tryptase+ cells were also detected. Statistical analysis showed significant correlations between c-kit (CD117)+ and tryptase, CD68 and erythrocyte sedimentation rate (ESR), ESR and red blood cell count (RBC), and prothrombin time and platelet count. The inverse correlation between RBCs in peripheral blood and ESR suggested that anemia associated with chronic inflammatory disease is a noncasual event in patients suffering from cardiac myxoma. Mechanical hemolysis may be only a minor component of anemia, according to the lack of correlation between echographic surface and RBCs. Moreover, tumor size did not correlate with ESR, showing that inflammatory state may depend from both tumor cells population and inflammatory infiltrate. In the future, modulation of macrophage polarization in cardiac myxomas might represent important therapeutic target.

Prevalence of Undiagnosed Diabetes in Rheumatoid Arthritis: an OGTT Study.

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by an excess of cardiovascular disease (CVD) risk, estimated to be at least 50% greater when compared to the general population. Although the widespread diffusion of type 2 diabetes mellitus (T2DM) awareness, there is still a significant proportion of patients with T2DM that remain undiagnosed. Aim of this cross-sectional study was to evaluate the prevalence of undiagnosed diabetes and prediabetes in RA patients. For the present study, 100 consecutive nondiabetic RA patients were recruited. Age- and sex-matched subjects with noninflammatory diseases (osteoarthritis or fibromyalgia) were used as controls. After overnight fasting, blood samples were obtained for laboratory evaluation including serum glucose, total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, uric acid, erythrocyte sedimentation rate (ESR), high sensitivity C-reactive protein (hs-CRP), rheumatoid factor (RF), and anti-Cyclic Citrullinated Peptide Antibodies (ACPA). A standard Oral Glucose Tolerance Test (OGTT) with 75 g of glucose was performed and blood samples were collected at time 0, 30, 60, 90, and 120 minutes, for measurement of plasma glucose concentrations. The prevalence of impaired fasting glucose (IFG) (9/100 vs 12/100, P = 0.49), impaired glucose tolerance (IGT) (19/100 vs 12/100, P = 0.17), and concomitant IFG/IGT (5/100 vs 9/100, P = 0.27) was similar between groups, whereas the prevalence of diabetes was significantly higher in RA patients (10/100 vs 2/100, P = 0.02). In a logistic regression analysis, increasing age (OR = 1.13, 95% CI 1.028-1.245, P = 0.01) and disease duration (OR = 1.90, 95% CI 1.210-2.995, P = 0.005) were both associated with an increased likelihood of being classified as prediabetes (i.e. IFG and/or IGT) or T2DM. A ROC curve was built to evaluate the predictivity of disease duration on the likelihood of being diagnosed with T2DM. The area under the ROC curve was 0.67 (95% CI: 0.56-0.78, P = 0.004). We identified the best cut-off of 33 months that yielded a sensitivity of 61% and a specificity of 70% for classification of T2DM patients. According to our data, RA seems to be characterized by an elevated prevalence of undiagnosed diabetes, especially in patients with longer disease duration.

Association between noninvasive fibrosis markers and chronic kidney disease among adults with nonalcoholic fatty liver disease.

Evidence suggests that nonalcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are associated with an increased risk of chronic kidney disease (CKD). In this study we aimed to evaluate whether the severity of liver fibrosis estimated by NAFLD fibrosis score is associated with higher prevalence of CKD in individuals with NAFLD. To this end NAFLD fibrosis score and estimated glomerular filtration rate (eGFR) were assessed in 570 White individuals with ultrasonography-diagnosed NAFLD. As compared with subjects at low probability of liver fibrosis, individuals at high and intermediate probability showed an unfavorable cardio-metabolic risk profile having significantly higher values of waist circumference, insulin resistance, high sensitivity C-reactive protein, fibrinogen, uric acid and lower insulin-like growth factor-1 levels. Individuals at high and intermediate probability of liver fibrosis have lower eGFR after adjustment for gender, smoking, glucose tolerance status, homeostasis model assessment index of insulin resistance (HOMA-IR index), diagnosis of metabolic syndrome, statin therapy, anti-diabetes and anti-hypertensive treatments (P = 0.001). Individuals at high probability of liver fibrosis had a 5.1-fold increased risk of having CKD (OR 5.13, 95%CI 1.13-23.28; P = 0.03) as compared with individuals at low probability after adjustment for age, gender, and BMI. After adjustment for glucose tolerance status, statin therapy, and anti-hypertensive treatment in addition to gender, individuals at high probability of liver fibrosis had a 3.9-fold increased risk of CKD (OR 3.94, 95%CI 1.11-14.05; P = 0.03) as compared with individuals at low probability. In conclusion, advanced liver fibrosis, determined by noninvasive fibrosis markers, is associated with CKD independently from other known factors.

Rosacea-like facial rash related to metformin administration in a young woman.

BACKGROUND: Since the skin represents a common site of adverse drug reactions, few data are reported at this time regarding the development of skin rash during the treatment with antidiabetic drugs. CASE PRESENTATION: We report a 29-year old woman that developed a facial skin rash during the treatment with metformin. Clinical and laboratory findings excluded the presence of systemic diseases, but several diagnosis and many drugs were administered without clinical improvement. The self-dismission of metformin induced an improvement of symptoms, while the re-challenge documented an impairments of skin rash. The Naranjo probability scale suggested a probable association between metformin and skin rash and metformin was definitively dismissed. CONCLUSION: We report for the first time a non vasculitis facial skin manifestation related to metformin in a young woman. However, this case may emphasizes the need to consider the ADRs as a differential diagnosis in order to reduce medical errors and the related medical costs.

Nonalpine thyroid angiosarcoma in a patient with hashimoto thyroiditis.

Thyroid angiosarcoma is an uncommon thyroid carcinoma and its incidence is the highest in the European Alpine regions. Thyroid angiosarcoma is also a very aggressive tumor that can rapidly spread to the cervical lymph nodes, lungs, and brain or can metastasize to the duodenum, small boewl, and large bowel. Although it is histologically well defined, clear-cut separation between the angiosarcoma and anaplastic thyroid carcinoma is difficult. A 49-year-old Caucasian female patient, born and resident in Southern Italy (Calabria), in an iodine-sufficient area, was admitted to the Surgery Department because she presented with a painless mass in the anterior region of neck enlarged rapidly in the last three months. After total thyroidectomy and right cervical lymphadenectomy, postoperative histological examination revealed the presence of a thyroid angiosarcoma with positive staining for CD31 and for both Factor VIII-related antigen and Vimentin and only partially positive for staining pancytokeratin and presence of metastasis in cervical, supraclavicular, mediastinal and paratracheal lymph nodes. The patient started adjuvant chemotherapy and she was treated for 6 cycles with Doxorubicin, Dacarbazine, Ifosfamide, and Mesna (MAID). After 22 months from surgery, the patient is still alive without both local and systemic recurrence of the disease.

Nonalcoholic fatty liver disease is associated with low circulating levels of insulin-like growth factor-I.

CONTEXT: Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and is associated with insulin resistance and cardiovascular disease. Among the potential factors that may account for the increased cardiometabolic risk, IGF-I is a plausible candidate because the liver is the main site of its production. OBJECTIVE: Our objective was to examine the relationship between NAFLD and IGF-I levels and to test the hypothesis that free fatty acids-induced insulin resistance might impair insulin-induced increase of GH receptor (GHR) expression in human hepatoma cells. SUBJECTS, DESIGN, AND SETTING: Five hundred three nondiabetic Caucasians participated in this ambulatory-care cross-sectional study. MAIN OUTCOME MEASURES: Cardiometabolic risk factors and liver ultrasound scanning were assessed. Insulin-induced expression of GHR in HuH7 human hepatoma cells exposed for 24 h to palmitate was determined by Western blotting and real-time PCR. RESULTS: After adjustment for age and gender, individuals with NAFLD had significantly higher body mass index, waist circumference, fasting insulin, triglycerides, homeostasis model assessment index, liver enzymes, and lower high-density lipoprotein cholesterol compared with control subjects. IGF-I levels were significantly lower in individuals with NAFLD (P = 0.001). Exposure of HuH7 hepatoma cells to palmitate caused a dose-dependent reduction in the insulin-induced increase of GHR expression. CONCLUSIONS: These data show that IGF-I levels are reduced in subjects with NAFLD and suggest that hepatic insulin resistance may affect IGF-I levels by modulating GH-stimulated synthesis of hepatic IGF-I.

Leptin-stimulated endothelial nitric-oxide synthase via an adenosine 5'-monophosphate-activated protein kinase/Akt signaling pathway is attenuated by interaction with C-reactive protein.

The AMP-activated protein kinase (AMPK) lies upstream of Akt in the pathway leading to endothelial NO synthase (eNOS) activation. Whether leptin promotes eNOS activation via AMPK-dependent activation of Akt, and which of the two AMPKalpha catalytic subunits is involved, remains unknown. Leptin resistance may be partly attributed to interaction between leptin and C-reactive protein (CRP). We hypothesized that leptin effect on eNOS activation in human aortic endothelial cells might be blunted by direct interaction with human recombinant CRP. Small interfering RNAs (siRNAs) were used to knock down expression of alpha1- or alpha2-AMPK in transient transfection assay to evaluate which is involved in this pathway and whether leptin effect on eNOS activation in human aortic endothelial cells might be blunted by direct interaction with human CRP. siRNA-mediated down-regulation of AMPKalpha1, but not AMPKalpha2, abolished leptin-induced Akt-Ser(473) phosphorylation, eNOS-Ser(1177) phosphorylation, eNOS activation, and cGMP accumulation. By contrast, siRNA-mediated knockdown of Akt1 did not affect AMPKalpha1 phosphorylation, but it abolished leptin-induced phosphorylation of Akt-Ser(473) and eNOS-Ser(1177), suggesting that Akt functions downstream of AMPKalpha1. Preincubation of leptin with human recombinant CRP impaired leptin-induced AMPK activation, eNOS-Ser(1177) phosphorylation, eNOS activity, and intracellular cGMP accumulation. The data are consistent with a model implicating an AMPKalpha1-->Akt-->eNOS pathway leading to NO production in response to leptin supporting the idea that interaction between leptin and CRP may have a role in impairing leptin effect on eNOS activation, suggesting a link between leptin resistance, low-grade inflammation, and endothelial dysfunction.

hNIS protein in thyroid: the iodine supply influences its expression and localization.

OBJECTIVE: Nonfunctioning thyroid nodules (NFTNs) display a diminished iodide-concentrating ability, owing to defective expression and cell membrane targeting of the sodium-iodide symporter (NIS). Since NIS expression is primarily modulated by thyroid iodine content in vitro and in animal models, we attempted to determine whether iodine supply influences the expression and localization of human NIS (hNIS) in NFTNs. DESIGN: Using immunohistochemistry, we analyzed cold hyperplastic nodules and nonnodular thyroid samples (controls) from patients living in iodine-sufficient (n = 19) or severely iodine-deficient (n = 15) areas. MAIN OUTCOME: Nodules from the iodine-sufficient area exhibited weak or absent hNIS immunostaining whereas almost all nodules from the iodine-deficient area were hNIS positive. Heterogeneous hNIS staining was common among the iodine-deficient samples (p = 0.028). hNIS was localized on membrane in all nodular samples from the iodine-deficient area and in less than 40% in the iodine-sufficient area. CONCLUSIONS: hNIS is adequately expressed and appropriately localized in NFTNs cell membrane from iodine-deficient areas and its expression in vivo is modulated by iodine supply.

HEX, PAX-8 and TTF-1 gene expression in human thyroid tissues: a comparative analysis with other genes involved in iodide metabolism.

OBJECTIVE: Benign and malignant thyroid tumours are characterized by alterations of the expression level of thyroid-specific genes involved in the iodide metabolism. Imbalance in the levels of transcription factors has been recognized as a critical molecular event in the development of neoplasm. The delineation of eventual correlations existing between the expression of transcription factors and of putative target genes in physiological and pathological conditions could be relevant to better understand tumorigenesis. PATIENTS AND METHODS: We examined the expression levels of transcription factors involved in thyroid development [thyroid transcription factor 1 (TTF-1), paired box gene 8 (PAX-8) and haematopoietically expressed homeobox (HEX)] in 101 thyroid tissues, including 14 normal thyroid tissues, 13 hyperfunctioning tissues, 27 benign adenomas and 47 follicular or papillary carcinomas. Then, we compared their expression levels with those of thyroid-specific genes involved in iodide metabolism. RESULTS: In benign tumours, PAX-8 and TTF-1 gene expression levels were not significantly different from the expression levels in normal tissues. However, a significant decrease was found in carcinomas. Interestingly, HEX gene expression was significantly decreased in both hyper- and hypofunctioning benign tissues and also in carcinomas. Expression levels of Pendred syndrome (PDS), natrium iodine symporter (NIS), thyroglobulin (Tg), thyroid peroxidase (TPO) and dual oxidase 1 or 2 (DUOX2) genes were significantly correlated with the expression of PAX-8 and with that of HEX. Expression level of TTF-1 was weakly correlated only with the expression levels of PDS and DUOX2. CONCLUSION: Our findings suggest that alterations in the transcription factors PAX-8, TTF-1 and HEX gene expression, by acting individually or together, have a role in both thyroidal tumorigenesis and in the dedifferentiation process.

Clinical case seminar: in vivo and in vitro characterization of a novel germline RET mutation associated with low-penetrant nonaggressive familial medullary thyroid carcinoma.

CONTEXT: RET mutation analysis provides useful information on the clinical outcome of medullary thyroid carcinomas (MTCs) and the risk of disease in the family members. OBJECTIVE: The objective of this study was to document genotype-phenotype relationships in an Italian family with a novel RET mutation. DESIGN/SETTING: RET gene alterations were investigated in a patient with unifocal MTC and her relatives. The identified mutation was subjected to in vitro functional testing. PATIENTS: Patients included a female proband who developed MTC at age 60, her five children, and three grandchildren. MAIN OUTCOME MEASURES: DNA extracted from the blood and the proband's tumor were analyzed for RET alterations. The transforming potential and mitogenic properties of the identified mutation were investigated. RESULTS: A novel heterozygous germline RET mutation at codon 777 (AAC-->AGC, N-->S) (RET/N777S) was identified in the proband and three of her relatives. Two of the latter presented thyroid nodules, but none had MTC or C cell hyperplasia. The proband's MTC was characterized by late onset and limited aggressiveness, with no evidence of regional lymph node or distant metastases 10 yr after total thyroidectomy. This phenotype is consistent with the RET/N777S mutant's low-grade transforming potential and limited activation of RET tyrosine kinase. CONCLUSION: Our findings indicate that the newly identified RET/N777S mutation is a low-penetrant cause of MTC disease. This phenotype might be less aggressive than that associated with MEN2A of familial MTC, although close clinical follow-up of carriers is essential.

Recovery of NIS expression in thyroid cancer cells by overexpression of Pax8 gene.

BACKGROUND: Recovery of iodide uptake in thyroid cancer cells by means of obtaining the functional expression of the sodium/iodide symporter (NIS) represents an innovative strategy for the treatment of poorly differentiated thyroid cancer. However, the NIS gene expression alone is not always sufficient to restore radioiodine concentration ability in these tumour cells. METHODS: In this study, the anaplastic thyroid carcinoma ARO cells were stably transfected with a Pax8 gene expression vector. A quantitative RT-PCR was performed to assess the thyroid specific gene expression in selected clones. The presence of NIS protein was detected by Western blot and localized by immunofluorescence. A iodide uptake assay was also performed to verify the functional effect of NIS induction and differentiation switch. RESULTS: The clones overexpressing Pax8 showed the re-activation of several thyroid specific genes including NIS, Pendrin, Thyroglobulin, TPO and TTF1. In ARO-Pax8 clones NIS protein was also localized both in cell cytoplasm and membrane. Thus, the ability to uptake the radioiodine was partially restored, associated to a high rate of efflux. In addition, ARO cells expressing Pax8 presented a lower rate of cell growth. CONCLUSION: These finding demonstrate that induction of Pax8 expression may determine a re-differentiation of thyroid cancer cells, including a partial recovery of iodide uptake, fundamental requisite for a radioiodine-based therapeutic approach for thyroid tumours.

Expression, regulation, and function of paired-box gene 8 in the human placenta and placental cancer cell lines.

Pax proteins are transcriptional regulators that control a variety of developmental decisions in vertebrates. During development, the paired-box gene 8 (PAX8) is expressed in the thyroid, kidney, and several areas of the central nervous system. It is also expressed in the adult thyroid gland, in which it mediates TSH-induced modulation of the expression of important genes, such as those encoding thyroglobulin, thyroperoxidase, and the sodium/iodide symporter (NIS). Thus far, placental expression of PAX8 has been described only in mice. In the present study, we show that PAX8 is also expressed in the human placenta at term. In an in vitro model of placental cancer, the JAR choriocarcinoma cell line, human chorionic gonadotropin (hCG) increased levels of PAX8 mRNA and protein, and gel retardation assays indicated that the up-regulation of PAX8 protein expression is associated with an increase in its DNA-binding activity. The effects of hCG were mimicked by forskolin, indicating that they are cAMP dependent. Levels of mRNA for the Wilms' tumor 1 (WT1) and NIS genes were increased in JAR cells by hCG treatment, whereas overexpression of PAX8 increased only levels of WT1 mRNA. In cells transfected with PAX8-specific small interfering RNA, the stimulatory effects of hCG on WT1 mRNA levels were abolished, but hormonal enhancement of NIS mRNA levels was unchanged. These findings indicate that, in JAR cells, hCG activates a cAMP-dependent pathway that can up-regulate WT1 expression through PAX8.