Putative protective role of autoantibodies against the insulin-like growth factor-1 receptor in Graves' Disease: results of a pilot study.

BACKGROUND: The insulin-like growth factor-1 receptor (IGF-1R) is a key element in the pathogenesis of Graves' Orbitopathy (GO), but the role of IGF-1R autoantibodies (IGF-1RAbs) has not been established. METHODS: We designed a cross-sectional investigation to measure IGF-1RAbs in patients with Graves' disease (GD), with or without GO, who underwent radioiodine therapy followed by glucocorticoids (GC). Twenty-nine patients were included, 15 of which with GO. Patients were evaluated at baseline and three and 6 months after radioiodine. The primary objective was the prevalence of positive tests for IGF-1RAbs. The secondary objectives were: (1) IGF-1RAbs concentrations and their variations; (2) relationship between IGF-1RAbs and the features of GO; (3) relationship between IGF-1RAbs and anti-thyroid autoantibodies. RESULTS: IGF-1RAbs above the cut-off value were found only in one patient with GD without GO. IGF-1RAb levels were greater in patients with GD without GO, at baseline (P < 0.0001), and after three (P < 0.0001) and six (P = 0.0001) months. No correlations were observed between IGF-1RAbs and the features of GO, nor between IGF-1RAbs and anti-thyroglobulin or anti-thyroperoxidase autoantibodies. There was an inverse correlation between anti-TSH receptor autoantibodies (TRAbs) and IGF-1RAb levels in GD patients with GO at 6 months (P = 0.03). CONCLUSIONS: IGF-1RAbs appear to be greater in patients with GD without GO compared with those with GO, suggesting a putative protective role of IGF-1RAbs on the development of GO, in line with the beneficial effects of Teprotumumab on GO. The inverse correlation between IGF-1RAbs and TRAbs 6 months after radioiodine may reflect antigen spreading and/or GC treatment.

Lifestyle and high density lipoprotein cholesterol in postmenopause.

OBJECTIVES: Menopause is characterized by hormonal and metabolic changes. These are linked to increased risk of cardiovascular disease, for which low blood plasma levels of high density lipoprotein (HDL) cholesterol are an independent risk factor. The present study investigated variables linked with basal plasma HDL cholesterol levels and the effects of aerobic training, on their variations, in 40 postmenopausal women. METHODS: We assessed body composition, dietary habits and maximal aerobic capacity of participants. Characteristics of daily physical activity and plasma lipoproteins were measured. The women walked on 4 days/week, for 14 weeks, at moderate intensity, and they were grouped according to the resulting tertiles of basal plasma HDL cholesterol levels. RESULTS: Logistic regression analysis showed that waist-to-hip ratio and number of daily bouts of moderate-intensity physical activity, held for at least 10 consecutive minutes (B10m/day), are predictive variables of basal plasma HDL cholesterol levels. After the training period, the first and second tertiles increased plasma HDL cholesterol levels, while the third tertile decreased plasma HDL cholesterol levels. The tertiles showed different remodelling of spontaneous physical activity: the third tertile reduced B10m/day, while the others did not. CONCLUSIONS: This study provides knowledge about the relationships of plasma HDL cholesterol levels with characteristics of physical activity. Furthermore, it shows that physical exercise engagement can result in negative compensation of spontaneous physical activity that could counteract or reduce the positive effects of the aerobic training on plasma HDL cholesterol levels.

Characteristics of spontaneous physical activity and executive functions in postmenopause.

AIM: Executive functions are susceptible to age-related changes, and menopause has also been shown to be linked with their decline. The aim of the present study was to investigate the variables related to executive functions in postmenopausal women not involved in controlled dietary and physical exercise programs and without hormone-replacement therapy. METHODS: Fifty-seven women (58.39 ±4.16 yr) were investigated for their medical history, blood lipids, insulin resistance (HOMA-IR), body composition, blood pressure, executive functions (Digit Span and Trail Making tests), maximal aerobic capacity, dietary habits, and spontaneous physical activity. RESULTS: Cluster analysis performed on the basal data of the Digit Span scores and Trail Making tests identified two subgroups: Group A (N.=24) that showed better executive functions than Group B (N.=33). Although these subgroups differed across several variables of body composition, plasma lipids, dietary habits, spontaneous physical activity, aerobic fitness, and insulin resistance, logistic regression models showed B10m/die as the only predictive variable for subgroup membership. CONCLUSION: In the absence of a physical exercise program, the knowledge of how spontaneous physical activity is organized (B10m/die) is important for executive functions of post-menopausal women. It is the specific moderate to intense physical activity characteristic of B10m/die, rather than generic physical activity, that seems to determine the maintenance or attainment of cognitive health through body movement.

Bone maturity and thyroidal status at birth: role of the ultrasonographic evaluation of the distal femoral epiphysis.

PURPOSE: Thyroidal hormones are important for bone development, and ultrasonographic (US) evaluation of the distal femoral epiphysis (DFE) has recently been suggested as a new method for the assessment of skeletal maturity in infants. A delayed bone maturation, expressed by a smaller or absent DFE nucleus (in terms of DFE surface area, sum of the epiphyseal diameters, or DFE height and acetabular size), has been largely demonstrated in diagnosed hypothyroid infants, while no data analyze the role and meaning of the DFE dimensions (in terms of volume) in newborn before knowledge of the congenital neonatal screening results. The aims of the present study were to ultrasonographically evaluate the volume of DFE in newborns, and to determine whether it has any predictive role for the thyroidal status at birth. MATERIALS AND METHODS: 238 newborns (M/F: 121 /117) were evaluated. The gestational age, body weight and length at birth were registered. Neonatal screening for congenital hypothyroidism (CH), based on TSH levels on blood spot, was performed in all on the 3 rd day of life. The DFE volume was ultrasonographically evaluated, taking into account the three diameters of the DFE nucleus, within 48 hours of birth. RESULTS: No newborn was found to have CH on neonatal screening. The DFE volume ranged between 0.00 cm and 0.61 cm (mean 0.14 ± 0.10 cm, median 0.13 cm). The DFE volume did not differ between males and females, while it was significantly greater in at term babies than in preterm babies. No differences in TSH values at screening were noted among the groups. The DFE volume was significantly related to gestational age, birth weight and length. A significant relationship was found between the DFE volume and TSH concentrations at screening. CONCLUSION: US evaluation of DFE volume provides a simple method for assessing bone maturity at birth, which is related to gestational age, body weight and length at birth. Nonetheless, it has any predictive role for thyroidal status at birth, being not related to TSH levels on neonatal screening for CH.

Transcriptional regulation of major histocompatibility complex class I gene by insulin and IGF-I in FRTL-5 thyroid cells.

Increased major histocompatibility complex (MHC) class I gene expression in nonimmune cell 'target tissues' involved in organ-specific diseases may be important in the pathogenesis of autoimmune diseases. This possibility in part evolves from studies of cultured thyrocytes where properties appear relevant to the development of thyroid autoimmune disease. In FRTL-5 rat thyroid cells in continuous culture, hormones and growth factors that regulate cell growth and function specifically decrease MHC class I gene expression. We hypothesized that this could reflect a mechanism to preserve self-tolerance and prevent autoimmune disease. The mechanisms of action of some of these hormones, namely TSH and hydrocortisone, have been already characterized. In this report, we show that IGF-I transcriptionally downregulates MHC class I gene expression and that its action is similar to that of insulin. The two hormones have a complex effect on the promoter of the MHC class I gene, PD1. In fact, they decrease the full promoter activity, but upregulate the activity of deleted mutants that have lost an upstream, tissue-specific regulatory region but still retain the enhancer A region. We show that insulin/IGF-I promotes the interactions of the p50/p65 subunits of NF-kappaB and AP-1 family members with these two regions, and that the tissue-specific region acts as a dominant silencer element on insulin/IGF-I regulation of promoter activity. These observations may be important to understand how MHC class I gene transcription is regulated in the cells.

[Nf-kB transcription factor: role in the pathogenesis of inflammatory, autoimmune, and neoplastic diseases and therapy implications]. / Il fattore di trascrizione NF-kB: ruolo nella patogenesi delle malattie infiammatorie, autoimmuni, neoplastiche e implicazioni terapeutiche.

PURPOSE: Description of the involvement of the transcription factor NF-kB in inflammatory, autoimmune and neoplastic processes. Clinical implications from basic research. DESIGN: Review of the most significant data reported in the literature and personal publications. RESULTS: NF-kB is an ubiquitous transcription factor member of the proto-oncogene family rel. NF-kB regulates the expression of several genes involved in inflammatory and immune responses. The classical activated form of NF-kB consists of the p50/p65 heterodimer, different dimers may be formed with members of rel, AP1, steroid hormones receptors family. Many studies suggest that NF-kB should be considered as an important mechanisms of inflammatory processes and autoimmune diseases. Many important anti-inflammatory drugs and immunosuppressants inhibit NF-kB. Several observations have suggested a role of the inappropriate activation of NF-kB in cell proliferation, transformation, and tumor development, mainly lymphomas. Conversely, it has been proposed that the activation of NF-kB in immune cells may contribute to anti-tumor immunity. CONCLUSIONS: NF-kB is an optimal target of anti-inflammatory and immunosuppresant therapies. Molecular studies on NF-kB are very important to understand the pathogenesis of inflammatory, autoimmune and neoplastic diseases, and to identify new drugs that inhibit NF-kB activation.

Transforming growth factor-beta1 down-regulation of major histocompatibility complex class I in thyrocytes: coordinate regulation of two separate elements by thyroid-specific as well as ubiquitous transcription factors.

Transforming growth factor (TGF)-beta1-decreased major histocompatibility complex (MHC) class I gene expression in thyrocytes is transcriptional; it involves trans factors and cis elements important for hormone- as well as iodide-regulated thyroid growth and function. Thus, in rat FRTL-5 thyrocytes, TGF-beta1 regulates two elements within -203 bp of the transcription start site of the MHC class I 5'-flanking region: Enhancer A, -180 to -170 bp, and a downstream regulatory element (DRE), -127 to -90 bp, that contains a cAMP response element (CRE)-like sequence. TGF-beta1 reduces the interaction of a NF-kappaB p50/fra-2 heterodimer (MOD-1) with Enhancer A while increasing its interaction with a NF-kappaB p50/p65 heterodimer. Both reduced MOD-1 and increased p50/p65 suppresses class I expression. Decreased MOD-1 and increased p50/p65 have been separately associated with the ability of autoregulatory (high) concentrations of iodide to suppress thyrocyte growth and function, as well as MHC class I expression. TGF-beta1 has two effects on the downstream regulatory element (DRE). It increases DRE binding of a ubiquitously expressed Y-box protein, termed TSEP-1 (TSHR suppressor element binding protein-1) in rat thyroid cells; TSEP-1 has been shown separately to be an important suppressor of the TSH receptor (TSHR) in addition to MHC class I and class II expression. It also decreases the binding of a thyroid-specific trans factor, thyroid transcription factor-1 (TTF-1), to the DRE, reflecting the ability of TGF-beta1 to decrease TTF-1 RNA levels. TGF-beta1-decreased TTF-1 expression accounts in part for TGF-beta1-decreased thyroid growth and function, since decreased TTF-1 has been shown to decrease thyroglobulin, thyroperoxidase, sodium iodide symporter, and TSHR gene expression, coincident with decreased MHC class I. Finally, we show that TGF-beta1 increases c-jun RNA levels and induces the formation of new complexes involving c-jun, fra-2, ATF-1, and c-fos, which react with Enhancer A and the DRE. TGF-beta1 effects on c-jun may be a pivotal fulcrum in the hitherto unrecognized coordinate regulation of Enhancer A and the DRE.

Thymosin-alpha1 regulates MHC class I expression in FRTL-5 cells at transcriptional level.

In this study we examined the effect of the synthetic peptide thymosin-alpha1 (T(alpha)1) on MHC class I expression in FRTL-5 cells. Treatment with T(alpha)1 increased expression of MHC class I surface molecules and mRNA, which reached its peak (153 +/- 8 % of the control value) after 12 h. Chloramphenicol acetyltransferase (CAT) analysis, following transfection with a plasmid containing the regulatory sequence of MHC class I (or its deletion derivatives) with the CAT reporter gene, and electrophoretic mobility shift assay experiments demonstrated that the action of T(alpha)1 was at the transcriptional level, and its mechanism of action is likely due to increased binding between the complex p50/fra-2 and the enhancer A sequence of the 5' flanking region of a swine class I gene (PD1). An increase in the expression of MHC class I surface molecules was also observed by flow cytometry in murine and human tumor cell lines and in primary cultures of human macrophages. This study shows for the first time an effect of Talpha1 on the regulation of gene expression at the molecular level, and may further contribute to explaining the results obtained using Talpha1 in the control of infectious diseases and tumor growth.

Zinc sulfate supplementation improves thyroid function in hypozincemic Down children.

In subjects affected by trisomy 21 (Down syndrome), hypothyroidism is the most common endocrinological deficit. Plasma zinc levels, which are commonly detected below the normal range in Down patients, are related to some endocrinological and immunological functions; in fact, zinc deficiency has been shown to impair immune response and growth rate. Aims of this study were to evaluate (1) the role of zinc deficiency in subclinical hypothyroidism and (2) thyroid function changes in Down children cyclically supplemented with zinc sulfate. Inverse correlations have been observed between age and triiodotironine (T3) and between zinc and thyroid-stimulating hormone (TSH); higher TSH levels have been found in hypozincemic patients at the beginning of the study. After 6 mo of supplementation, an improvement of thyroid function (TSH levels: 3.96 +/- 1.84 vs 2.64 +/- 1.33 mUI/mL basally and after 6 mo, respectively) was observed in hypozincemic patients. In the second cycle of supplementation, a similar trend of TSH was observed. At the end of the study, TSH significantly decreased in treated hypozincemic subjects (4.48 +/- 1.93 vs 2.96 +/- 1.20 mUI/mL) and it was no longer different in comparison to normozincemic patients. We suggest zinc supplementation to the diet in hypozincemic Down children as a simple and useful therapeutic tool.

[The clinical use of human recombinant TSH]. / Impiego clinico del TSH umano ricombinante.

The recent cloning of human TSH-beta gene has allowed the production of recombinant human TSH (rhTSH) by recombinant DNA technology in mammalian cells (Chinese hamster ovary cells). Studies aimed at biochemical and biological characterization have shown that rhTSH, unlike pituitary TSH, is highly sialylated and is biological active in stimulating c-AMP accumulation in FRTL-5 cells. Phase I/II and phase III clinical studies have been performed to evaluate the safety and efficacy of rhTSH in stimulating radioactive iodine uptake in patients after total thyroidectomy for differentiated thyroid cancer. In these patients therapy with thyroid hormones is performed to replace hormone production and to suppress TSH-stimulated tumor growth. To detect residual or recurrent cancer, the therapy has to be withdrawn in order to obtain rise in endogenous TSH to perform a total body scan. rhTSH, as a source of exogenous human TSH, has been shown as an additional diagnostic tool in the follow-up of patients with thyroid cancer. Used in patients maintained on thyroid hormone suppressive therapy, rhTSH enhances the sensitivity of serum Tg testing. Although the sensitivity of scans obtained after rhTSH administration is slightly lower than that after thyroid hormone withdrawal, the use of rhTSH avoids the clinical signs and symptom of hypothyroidism and can be used in selected patients.

Thyroid function and plasma selenium in chronic uremic patients on hemodialysis treatment.

It has been shown recently that Selenium (Se), an essential trace element for humans, is involved in the regulation of thyroid function, since the enzyme that catalyzes the liver conversion of the thyroid hormone T4 to the more active form T3 is a selenoenzyme. In chronic uremic patients, low blood Se levels as well as thyroid function abnormalities are often found. The present study was carried out to verify whether any correlation exists between Se levels and thyroid function, and to evaluate possible changes in hormonal pattern during Se supplementation in 10 chronic uremic patients on hemodialysis (HD) treatment. Se was supplemented orally as sodium selenite over six consecutive months. Basic plasma Se levels were significantly lower in patients than in normal controls. Right from the start of Se supplementation, plasma Se concentration promptly normalized and leveled off in the normal range throughout the study. Significant increase of FT3 and reduction of TSH levels were detected during Se supplementation. In Se-supplemented patients, a significant direct correlation was also found between reverse T3 (rT3) and TSH, and a significant inverse correlation was found between Se and TSH. Our results suggest that Se deficiency in chronic uremic patients represents a factor influencing the thyroid function and that the Se status should be determined in the evaluation of thyroid metabolism in these patients.

Purification and characterization of recombinant human thyrotropin (TSH) isoforms produced by Chinese hamster ovary cells: the role of sialylation and sulfation in TSH bioactivity.

The biological significance of glycosylation variants of pituitary glycoprotein hormones remains controversial because of the indirect methods usually employed to determine carbohydrate composition or structure as well as the use of unreliable biological/immunological ratio to determine bioactivity. We have previously characterized recombinant human TSH (rhTSH) secreted by Chinese hamster ovary cells attached to microcarrier beads in a large scale bioreactor after stable transfection of hCG alpha and hTSH beta minigenes. In the present study rhTSH has been used as a model to determine structure-function relationships of different isoforms of glycoprotein hormones. We have now produced greater than 200 mg rhTSH using a hollow fiber bioreactor. The highly purified rhTSH produced in the hollow fiber bioreactor (rhTSH-N) as well as rhTSH commercially produced in a large scale bioreactor (rhTSH-G) were quantitated by immunoassays, receptor binding assay, and amino acid analysis and further characterized by a variety of physico-biochemical methods, including chromatofocusing and carbohydrate analysis. rhTSH-G, rhTSH-N, as well as pituitary human TSH (phTSH) have been separated by chromatofocusing on a Mono P column into several isoforms with different pI values. Compositional analysis of the fractions showed higher sialic acid content in the more acidic rhTSH-G fractions. phTSH acidic isoforms showed higher total sulfate and sialic acid contents than the more basic fractions. The bioactivities of various TSH isoforms based on rigorous quantitation of mass by amino acid analysis determined in three different FRTL-5 cell bioassays showed that the more basic and less sialylated fractions of rhTSH-G were more active than the more acidic fractions. In contrast to the in vitro data, highly sialylated and acidic rhTSH-G isoforms showed longer plasma half-lives and higher in vivo bioactivity than the basic forms. These results indicate that secreted rhTSH, similar to intrapituitary phTSH, exists as a mixture of charge isoforms that are related at least in part to the degree of sialylation. The degree of sialylation, highly dependent on the bioreactor production conditions, appears to be the major factor affecting the charge heterogeneity, MCR, and bioactivity of rhTSH.

Purification and characterization of a 90 kDa protein released from human tumors and tumor cell lines.

A novel tumor-associated protein, termed 90K, and recognized by mAb SP-2 was purified from serum of breast cancer patients, ovarian cancer ascitic fluid and conditioned medium of human breast cancer cells. In these three sources, native 90K is present as a high molecular weight complex that was dissociated by SDS-PAGE into a major band of approximately 90,000 Da. On the basis of electrophoretic mobility, buoyant density value, amino acid composition, and immunoreactivity, the 90K from the different sources appeared to be identical. NH2-terminal amino acid sequence revealed no homology to known protein.

[Autonomous thyroid nodule: relations between clinical symptomatology and goiter endemia]. / Il nodulo autonomo tiroideo: correlazione fra sintomatologia clinica ed endemia gozzigena.

Sixty-three patients with autonomous thyroid nodule were studied, thirty-five from an endemic goiter area (EA) and twenty-eight from a non-endemic goiter area (NEA). Clinical history, physical examination, ultrasonography, thyroid hormone levels, and fine needle aspiration (FNA), were utilized to investigate whether or not iodine deficiency determined differences in the latency of progression to toxicity, the seriousness of illness and thyroid hormone levels. No significant difference was observed in the age of onset of nodularity, while the latency of progression to toxicity was significantly decreased in the EA (p less than 0.001). The ultrasonographic pattern did not show significant volume variations between the EA and NEA, but there was a slight prevalence of multinodular lesions in EA. No significant difference in serum thyroid hormone levels was found between the two areas in non toxic patients, while at the onset of hyperthyroidism higher levels of FT were observed in the EA than in the NEA. FNA showed a prevalence of colloid lesions in EA, while hyperplastic lesions prevail in the NEA. Forty-two patients underwent surgery: the extent of surgery was greater in patients from the EA. In conclusion, in iodine deficient areas earlier clinical thyrotoxicosis and a higher prevalence of hypoactive thyroid nodules were observed. Furthermore, in EA, the autonomous nodule in non toxic phase is more frequently associated with colloid lesions than hyperplastic lesions.