[New therapeutic options in obesity]. / Kampf den Pfunden! Unsere wirksamsten Waffen gegen die Volkskrankheit Adipositas.

The basis for a therapeutic concept for obesity comprises specific measures aimed at changing inappropriate lifestyle habits (overeating, unsuitable diet, sedentary lifestyle) and psychological counseling (identification of bad eating habits, motivation, intensive coaching). Education by a physician on an individual or small-group basis, with emphasis on the practical implementation of fitness training (endurance and muscle building!), together with modification of the diet, has proved successful. In parallel with this, supportive anti-obesity medication makes a useful contribution to weight reduction and the control of risk factors. Evidence-based anti-obesity drugs such as sibutramine and orlistat facilitate the start of weight reduction, thus providing additional motivation of success, and support the long-term effect by stabilizing the weight loss. Health insurance carriers should, in future, selectively support evaluated and approved medication-based and non-medication-based weight-reduction programs, and reimburse the patient who has successfully participated in one.

[Interactions of fibroblasts, adipocytes and immunocompeent cells in the pathogenesis of endocrine ophthalmopathy]. / Interaktionen von Fibroblasten, Adipozyten und immunkompetenten Zellen in der Pathogenese der endokrinen Orbitopathie.

Graves' ophthalmopathy is thought to result from a complex interplay of genetic and environmental factors. Various genes including those coding for HLA may determine a patient's susceptibility to the disease and its severity, but in addition numerous and often unknown environmental factors may determine its course. The orbital immune process is thought to be initiated, on the background of a permissive immunogenetic milieu, by circulating T cells directed against certain antigens on thyroid follicular cells that also recognize antigenic epitopes which are shared by tissues contained in the orbital space. Analysis of variable region genes of T cell antigen receptors in orbital T cells of patients with active Graves' ophthalmopathy has revealed limited variability of TcR V gene usage, suggesting that antigen-driven selection and/or expansion of specific T cells may occur during the early stages of Graves' ophthalmopathy. T cell recruitment into the orbital tissues is facilitated by certain chemokines and cytokines, which attract T cells by stimulating the expression of several adhesion molecules (e.g. ICAM-1, VCAM-1, CD44) in vascular endothelium and connective tissue cells. Adhesion molecules are known to be important for a variety of interactions between immunocompetent cells, preadipocyte fibroblasts and adipocytes. In addition, these molecules play a central role in lymphocyte activation and localization, facilitating antigen recognition, T cell costimulation, and various effector-target cell functions at the inflammatory sites, which result in amplification of the cellular immune process in active Graves' ophthalmopathy. T cells and macrophages populate the orbital space and release a number of cytokines (most likely a Th-1-type spectrum) into the surrounding tissues. Cytokines, oxygen free radicals and fibrogenic growth factors, released both from infiltrating inflammatory and residential cells, act upon orbital preadipocytes in a paracrine and autocrine manner to stimulate adipogenesis, fibroblast proliferation, glycosaminoglycan synthesis, and the expression of immunomodulatory molecules. Smoking, a well-known aggravating factor in Graves' ophthalmopathy, may aggravate tissue hypoxia and exert important immunomodulatory and pro-oxidant effects. Differentiation of orbital preadipocyte fibroblasts into mature adipocytes expressing increased levels of TSHR may also be driven by stimulation with circulating or locally produced cytokines or effectors. TSHR-directed autoantibodies or T cells may thus play a direct role promoting adipogenesis, glycosaminoglycan synthesis and expression of immunomodulatory proteins within the orbits. Once the net effect of these changes has come to increase the volume of the fatty connective tissues within the orbit, then proptosis, extraocular muscle dysfunction, and periorbital congestion will ensue.

Autoimmunity involving the human sodium/iodide symporter: fact or fiction?

Presence, functional activity and clinical relevance of autoantibodies directed against the human sodium iodide symporter (NIS) in thyroid autoimmune diseases have become the subject of much controversy in recent years. Earlier reports have claimed that NIS may represent a major thyroid autoantigen that elicits formation of functionally relevant autoantibodies in a significant proportion of patients with Graves' disease (GD) and Hashimoto's thyroiditis (HT). Moreover, a recent study has extended this notion by reporting detection of NIS-autoantibodies in 22% and 24% of a small number of patients with GD and HT, respectively, but not in patients with other autoimmune diseases. However, in striking contrast to these reports, two independent groups of investigators have now presented convincing evidence that NIS-directed autoantibodies occur with low frequency among a large sample of patients with autoimmune thyroid diseases. Moreover, no evidence of specific iodide uptake inhibiting activity was obtained once sera had been subjected to dialysis and/or IgG extraction. Thus, although the controversy has not been definitively resolved, hNIS does not appear to be a major functionally relevant antigen in autoimmune thyroid diseases. Moreover, when detected in addition to TPO and TSH receptor autoantibodies, NIS-directed autoantibodies do not appear to contribute any diagnostic power for GD and HT.

Sodium iodide symporter-based strategies for diagnosis and treatment of thyroidal and nonthyroidal malignancies.

The recent cloning and molecular characterization of the sodium iodide-symporter (NIS) has inspired novel approaches to the diagnosis and treatment of thyroidal and nonthyroidal malignancies. This article briefly reviews the physiologic regulation of NIS expression by cytokines, the expression in benign and malignant thyroidal diseases, and the expression in extrathyroidal tissues. Current concepts for NIS-based cancer therapy in thyroidal and extrathyroidal tumors are presented. The recent discovery of NIS expression in a majority of breast cancers as well as its promising application for prostate cancer imply potential applications in diagnostic imaging and radioiodine anticancer therapy for these highly common and lethal malignancies.

Receptor activator of nuclear factor-kappaB ligand and osteoprotegerin: potential implications for the pathogenesis and treatment of malignant bone diseases.

BACKGROUND: The current review summarizes the roles of the ligand, receptor activator of nuclear factor-kappaB ligand (RANKL), its receptor, receptor activator of nuclear factor-kappaB (RANK), and its decoy receptor, osteoprotegerin (OPG), on osteoclast biology and bone resorption. Furthermore, it highlights the impact of these compounds on the pathogenesis of malignant bone diseases, including tumor metastasis, humoral hypercalcemia of malignancy, and multiple myeloma. Finally, the authors discuss the therapeutic potential of OPG in the management of malignancies involving the skeleton. METHODS: After its discovery and cloning, the biologic effects of RANKL, RANK, and OPG have been characterized by in vitro experiments and in vivo studies. The generation of knock-out mice and transgenic mice has produced animal models with absent or excessive production of these cytokine components that display opposite abnormal skeletal phenotypes (osteoporosis or osteopetrosis). The potential effect of RANKL and OPG has been assessed by evaluating these compounds in various animal models of metabolic and malignant bone disease and by administering OPG to humans. RESULTS: Abnormal bone resorption due to local or systemic stimulation of osteoclast differentiation and activation is a hallmark of various benign and malignant bone diseases. RANKL, RANK, and OPG form an essential cytokine system that is capable of regulating all aspects of osteoclast functions, including proliferation, differentiation, fusion, activation, and apoptosis. The balance of bone resorption depends on the local RANKL-to-OPG ratio, which is enhanced in bone metastases and humoral hypercalcemia of malignancy. The exogenous administration of OPG to tumor-bearing animals corrects the increased RANKL-to-OPG ratio, and reverses the skeletal complications of malignancies. CONCLUSIONS: Abnormalities of the RANKL/OPG system have been implicated in the pathogenesis of various primary and secondary bone malignancies. The systemic administration of OPG appears to be a potent novel therapeutic agent for treatment of these disorders.

Role of receptor activator of nuclear factor-kappaB ligand and osteoprotegerin in bone cell biology.

Receptor activator of nuclear factor (NF-kappaB) ligand (RANKL), its cellular receptor, receptor activator of NF-kappaB (RANK), and the decoy receptor osteoprotegerin (OPG) constitute a novel cytokine system. RANKL produced by osteoblastic lineage cells and activated T lymphocytes is the essential factor for osteoclast formation, fusion, activation, and survival, thus resulting in bone resorption and bone loss. RANKL activates its specific receptor, RANK located on osteoclasts and dendritic cells, and its signaling cascade involves stimulation of the c-jun, NF-kappaB, and serine/threonine kinase PKB/Akt pathways. The effects of RANKL are counteracted by OPG which acts as a soluble neutralizing receptor. RANKL and OPG are regulated by various hormones (glucocorticoids, vitamin D, estrogen), cytokines (tumor necrosis factor alpha, interleukins 1, 4, 6, 11, and 17), and various mesenchymal transcription factors (such as cbfa-1, peroxisome proliferator-activated receptor gamma, and Indian hedgehog). Transgenic and knock-out mice with excessive or defective production of RANKL, RANK, and OPG display the extremes of skeletal phenotypes, osteoporosis and osteopetrosis. Abnormalities of the RANKL/OPG system have been implicated in the pathogenesis of postmenopausal osteoporosis, rheumatoid arthritis, Paget's disease, periodontal disease, benign and malignant bone tumors, bone metastases, and hypercalcemia of malignancy, while administration of OPG has been demonstrated to prevent or mitigate these disorders in animal models. RANKL and OPG are also important regulators of vascular biology and calcification and of the development of a lactating mammary gland during pregnancy, indicating a crucial role for this system in extraskeletal calcium handling. The discovery and characterization of RANKL, RANK, and OPG and subsequent studies have changed the concepts of bone and calcium metabolism, have led to a detailed understanding of the pathogenesis of metabolic bone diseases, and may form the basis of innovative therapeutic strategies.

Osteoprotegerin serum levels in men: correlation with age, estrogen, and testosterone status.

Previous studies have suggested an important role for androgens and estrogens in bone metabolism in men. However, their local mode of action has not been clearly established. Osteoprotegerin (OPG) is a secreted decoy receptor that inhibits osteoclast formation and activity by neutralizing its cognate ligand. To assess the role of OPG on bone metabolism in men, we conducted a study aimed at evaluating OPG serum levels and their correlation with age, bone mineral density, biochemical markers of bone turnover, and testosterone and estradiol levels in 252 men, aged 19-85 yr. Serum concentrations of OPG increased significantly with age (r = 0.41; P = 0.0001), and were positively correlated with free testosterone index and free estradiol index (r = 0.20; P < 0.002 and r = 0.15; P < 0.03, respectively) after adjustment for age and body weight. Beyond the age of 40 yr, OPG serum concentrations were negatively correlated with urinary excretion of total deoxypyridinoline (r = -0.20; P < 0.01) and PTH serum levels (r = -0.23; P < 0.01). In contrast, there was no correlation with biochemical markers of bone formation, 25-hydroxyvitamin D(3) levels, or bone mineral density at any site. Our data reveal that age as well as androgen and estrogen status are significant positive determinants, whereas PTH is a negative determinant, of OPG serum levels in men. These data suggest that OPG may be an important paracrine mediator of bone metabolism in elderly men and highlight the role of estrogens in the homeostasis of the male skeleton.

Expression of the sodium iodide symporter in human kidney.

BACKGROUND: The human sodium iodide symporter (hNIS) is a transmembrane protein that mediates the active transport of iodide in the thyroid gland. Following cloning of NIS, NIS expression has been detected in a broad range of nonthyroidal tissues, suggesting that iodide transport in these tissues is conferred by the expression of functional NIS protein. METHODS: The aim of this study was to examine functional hNIS expression in kidney by reverse transcription-polymerase chain reaction (RT-PCR), ribonuclease protection assay (RPA), immunohistochemistry, and Western blot analysis accompanied by iodide accumulation studies in kidney cells. RESULTS: Using a pair of full-length hNIS-specific oligonucleotide primers, RT-PCR followed by Southern hybridization revealed hNIS mRNA expression in normal human kidney tissue. The PCR products were subjected to automated sequencing and revealed full identity with the published human thyroid-derived NIS cDNA sequence. Furthermore, positive protected bands indicating the presence of hNIS mRNA were apparent in RPA gel lanes corresponding to human kidney cells as well as Chinese hamster ovary (CHO) cells stably transfected with hNIS cDNA and Graves' thyroid tissue. Immunohistochemical analysis of normal human kidney tissue using a mouse monoclonal hNIS-specific antibody showed marked hNIS-specific immunoreactivity confined to tubular cells, while no hNIS-specific immunoreactivity was detected in the glomeruli. NIS protein expression in human kidney cells was further confirmed by Western blot analysis. In addition, accumulation of (125)I was detected in human kidney cells in vitro and was shown to be sodium dependent and sensitive to perchlorate. CONCLUSIONS: Functional hNIS expression was demonstrated in the renal tubular system, suggesting that renal iodide transport may be, at least in part, an active process driven by NIS.

Immunosuppressive therapy in patients with thyroid eye disease: an overview of current concepts.

Thyroid eye disease (TED) is a debilitating disease impairing the quality of life of affected patients. Treatment is often not satisfactory. This review summarizes the existing literature and discusses the most widely used forms of treatment for TED such as glucocorticoids (GCs), and other immunosuppressive agents. GCs are the most commonly used treatment in patients with TED. Other immunosuppressive agents such as cyclosporin A, azathioprin, cyclophosphamide and ciamexone have been used, but the results are modest at best and indicate an unfavorable benefit-risk relationship. Limited experience indicates that methotrexate may be effective even in patients with refractory TED. Somatostatin analogs, octreotide and lanreotide, may provide a valuable, although costly, therapeutic alternative to GCs. Orbital radiotherapy has been used in the management of TED for almost 60 years. However, its beneficial effects have been questioned recently by several studies, the details of which have not yet been published. Other studies have argued in favor of orbital radiotherapy; however, the benefits appear to be limited to improvement of extraocular muscle dysfunction.

Serum levels of tumor necrosis factor-alpha, soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, and soluble interleukin-1 receptor antagonist in patients with thyroid eye disease undergoing treatment with somatostatin analogues.

The aim of this prospective, randomized study was to investigate the serum levels of tumor necrosis factor-alpha (TNF-alpha), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble interleukin-1 receptor antagonist (sIL-1RA) in patients with thyroid eye disease (TED) before and 1 and 3 months after treatment with somatostatin analogues (SM-a). Thirty patients, all with signs and symptoms of TED, were studied. Twenty-two patients (13 females) had active eye disease with a clinical activity score (CAS) > or = 4 (patients with active disease [PA]) and 8 patients (5 females) had inactive TED with CAS < or = 3 (patients with inactive disease [PI]). All PA patients had a positive orbital octreoscan, whereas PI patients had a negative one. Fifteen patients from the PA group were selected randomly and received SM-a (PA-S subgroup), while the remaining 7 patients were used as control subgroup (PA-C), received neither therapy, nor placebo. From the 15 patients who received SM-a (PA-S), 6 received octreotide (OCT) and 9 lanreotide (LRT). TED was reevaluated using the CAS 1 and 3 months after the initiation of SM-a treatment. Ten healthy individuals (6 females) were used as controls (group C). We found an increase in the basal levels of TNF-alpha (14.2 +/- 7.1 pg/mL), sICAM-1 (809.1 +/- 167.0 ng/mL), and sIL-1RA (542.1 +/- 259.0 pg/mL) in PA patients as a total group compared with the PI (1.6 +/- 1.9, 676.8 +/- 73.4, 267.6 +/- 152.8, respectively) group and C (1.9 +/- 1.4, 598.0 +/- 126.2, 258.6 +/- 155.1, respectively). The basal levels of TNF-alpha (13.3 +/- 8.3 pg/mL) and sIL-1RA (533.7 +/- 308.9 pg/mL) in PA-S as well as in PA-C (16.0 +/- 2.9, 560.2 +/- 107.3, respectively) subgroups were also increased compared with PI patients and C (1.9 +/- 1.4 and 258.6 +/- 155.1, respectively). The same was true for sICAM-1 when baseline levels compared with C (817.1 +/- 187.3 and 791.9 +/- 123.5, respectively vs. 598.0 +/- 126.2 ng/mL). After SM-a, serum levels of sICAM-1 and sVCAM-1 were decreased significantly 1 (781.2 +/- 205.9, 1,193.5 +/- 511.8 ng/mL) and 3 months (786.8 +/- 199.6, 1,122.1 +/- 225.3 ng/mL) after the initiation of treatment. In conclusion, serum levels of TNF-a, sICAM-1, and sIL-1RA were elevated in patients with active TED compared to controls. Furthermore, sICAM-1 and sVICAM-1 levels declined during the treatment with SM-a in patients with active TED.

Thyrotrophin receptor protein expression in normal and adenomatous human pituitary.

Thyrotrophin (TSH) synthesis and secretion is under the positive control of thyrotrophin releasing hormone and under the negative control of the thyroid hormones. However, it is hypothesised that TSH has a direct effect on the regulation of its own synthesis through an intrapituitary loop mediated by pituitary TSH receptors (TSH-R). The aim of this investigation was to study the expression of TSH-R in normal human pituitary at mRNA and protein levels, and to compare the pattern of protein expression between different pituitary adenomas. Using RT-PCR we were able to detect TSH-R mRNA in the normal pituitary, and immunohistochemical studies showed TSH-R protein expression in distinct areas of the anterior pituitary. Double immunostaining with antibodies against each of the intrapituitary hormones and S100 revealed that TSH-R protein is present in thyrotrophs and folliculostellate cells. Examination of 58 pituitary adenomas, including two clinically active and two clinically inactive thyrotroph adenomas, revealed TSH-R immunopositivity in only the two clinically inactive thyrotroph adenomas. This study shows, for the first time, the presence of TSH-R protein in the normal anterior pituitary and in a subset of thyrotroph adenomas. The expression of TSH-R in the thyrotroph and folliculostellate cell subpopulations provides preliminary evidence of a role for TSH in autocrine and paracrine regulatory pathways within the anterior pituitary gland.

Thyroid-associated eye disease.

Graves' ophthalmopathy (GO) is thought to result from a complex interplay of genetic and environmental factors. Various genes, including those coding for HLA, may determine a patient's susceptibility to the disease and its severity, but in addition, numerous and often unknown environmental factors may determine its course. Once established, the chronic inflammatory process within the orbital tissues appears to take on a momentum of its own. Based upon our current state of knowledge, we propose the working scheme shown in Fig. 1 for the pathogenesis of GO: Against the background of a permissive immunogenetic milieu, circulating T cells in patients with Graves' Disease (GD), directed against certain antigens on thyroid follicular cells, recognize antigenic epitopes that are shared by tissues contained in the orbital space. Here, preadipocytes and fibroblasts most likely act as target and effector cells of the orbital immune process. This includes preadipocyte fibroblasts present in the perimysium of extraocular muscles, which do not appear to be immunologically or metabolically different from those located in the orbital connective tissue. Differentiation of orbital preadipocyte fibroblasts into mature adipocytes expressing increased levels of TSHR may be driven by stimulation with circulating or locally produced cytokines or effectors. To date, it is still unknown how autoreactive T cells escape deletion by the immune system and become directed against a self-antigen that is presented by cells residing in the thyroid gland and in certain extrathyroidal locations. Mimicry of a host antigen by a microorganism or presentation of an altered self-antigen may promote proliferation and expansion of autoreactive T cell clones. T cell recruitment into the orbital tissues is facilitated by certain chemokines and cytokines, which help to attract T cells by stimulating the expression of several adhesion molecules (e.g. ICAM-1, VCAM-1, CD44) in vascular endothelium and connective tissue cells. Adhesion molecules are known to be important for a variety of interactions between immunocompetent cells, connective tissue cells and extracellular matrix components. In addition, these molecules play a central role in lymphocyte activation and localization, facilitating antigen recognition, T cell costimulation, and various effector-target cell functions at the inflammatory sites, many of which result in amplification of the cellular immune process in active GO. Analysis of variable region genes of T cell antigen receptors in orbital T cells of patients with active GO has revealed limited variability of TcR V gene usage, suggesting that antigen-driven selection and/or expansion of specific T cells may occur during the early stages of GO. T cells and macrophages populate the orbital space and release a number of cytokines (most likely a Th-1-type spectrum) into the surrounding tissues. Cytokines, oxygen free radicals and fibrogenic growth factors, released both from infiltrating inflammatory and residential cells, act upon orbital preadipocytes in a paracrine and autocrine manner to stimulate adipogenesis, fibroblast proliferation, glycosaminoglycan synthesis, and the expression of immunomodulatory molecules. Smoking, a well-known aggravating factor in GO with an uncertain mode of action, may aggravate tissue hypoxia and exert important immunomodulatory effects. Finally, the long-held hypothesis of a thyroid cross-reactive antigen within the orbital tissues has recently gained significant support from an animal model of ophthalmopathy, and from in vitro and ex vivo studies. If confirmed by immunological studies, these data may well explain the localized infiltration of the orbital tissues by autoreactive lymphocytes that share intriguing molecular features with intrathyroidal lymphocytes. Local release of certain cytokines, TSHR-directed autoantibodies, or other factors might further enhance adipogenesis, glycosaminoglycan synthesis and expression of

Lack of association of nonautoimmune hyperfunctioning thyroid disorders and a germline polymorphism of codon 727 of the human thyrotropin receptor in a European Caucasian population.

Constitutively activating mutations of the human TSH receptor (hTSHR) gene have been implicated as a major cause of hyperfunctioning nonautoimmune thyroid disease. However, significant geographic differences in the prevalence of these mutations have been observed. Recently, a high frequency of a germline polymorphism at codon 727 of the cytoplasmic tail of the hTSHR has been demonstrated in patients with toxic multinodular goiter. In the present study we assessed whether the codon 727 polymorphism is associated with hyperfunctioning thyroid adenomas. PCR followed by restriction enzyme digestion were used to genotype a total of 128 European Caucasian patients with toxic nonautoimmune thyroid disease (83 with toxic adenoma, 31 with toxic multinodular goiter, and 14 with disseminated autonomy) and to compare their codon 727 polymorphism frequencies with those of 99 healthy controls and 108 patients with Graves' disease. All individuals were drawn from an identical ethnic background. Sequencing of PCR products was used to confirm the mutation analysis. We found no significant differences in codon 727 polymorphism frequencies between patients with autonomously functioning thyroid disorders (13.3%) and the healthy control group (16.2%; P = 0.57). Moreover, the subtypes of toxic nonautoimmune thyroid disease (toxic adenoma, 13.2%; multinodular goiter, 9.6%; disseminated autonomy, 21.4%) were not related to significant differences in codon 727 polymorphism frequencies compared with the healthy control group (P = 0.67, P = 0.40, and P = 0.70, respectively). Additionally, there were no significant differences between patients with Graves' disease (21.3%) and healthy controls (P = 0.38). In conclusion, our data do not support an association between the codon 727 polymorphism of the hTSHR and toxic thyroid adenomas or toxic multinodular goiter in our study population. Thus, the codon 727 polymorphism of the hTSHR does not appear to be involved in the evolution of autoimmune or nonautoimmune hyperthyroidism in the European Caucasian population.

Clinical significance of saccade analysis in early active Graves' ophthalmopathy.

PURPOSE: To assess whether saccadic eye movements show distinct changes in patients with early active Graves' ophthalmopathy (GO), which could serve as a diagnostic tool for early detection and treatment. METHODS: Each of two prospective studies included 10 patients with early acute GO and 10 age- and sex-matched control subjects. In the explorative study (ES) 15 dynamic parameters of saccades were analyzed. In the comparative study (CS) only those parameters were evaluated, which in ES had shown significant differences between patients and controls. Horizontal and vertical saccades of 10 degrees, 20 degrees, and 40 degrees including a fatigue test were recorded binocularly using the induction scleral search coil. RESULTS: The differences of saccadic dynamics between patients and controls were small, whereas intra- and interindividual standard deviations were large. In ES, 7.1% of the parameters showed significant differences at a level of P < or = 0.05. In CS, 2.1% of all parameters revealed repetitive significant differences. Despite statistical significance, individual data did not allow differentiation between patients and healthy individuals due to high standard deviations. CONCLUSIONS: In early active GO no clinically relevant saccadic changes were detected. These findings may be based on adaptation of the central saccadic generator. Inclusion of patients with fibrotic muscle changes due to long-standing disease could explain the contrasting results of previous studies. Consequently, analysis of saccades does not serve as a diagnostic tool during early active GO.