Pathogenesis of Graves' orbitopathy: a 2010 update

The phenotype of Graves' orbitopathy is associated with thyrotropin receptor antibody levels

PURPOSE

Graves' orbitopathy (GO) is a specific inflammatory disorder of the orbit characterized by a highly heterogeneous clinical phenotype. The role of thyrotropin receptor antibodies (TSH-R-Ab) has been widely researched, however there is still no evidence that these antibodies have a direct pathogenic role in this pathology. The aim of this study was to examine their relation to the individual clinical features of GO.

METHODS

Ninety-one consecutive patients with GO were recruited. Total antibody concentration (TSH-R binding inhibitory immunoglobulins, TBII) and their functional activity (stimulating TSH-R-Ab, TSAb) were measured using binding immunoassay and cell-based bioassay, respectively.

RESULTS

Both TSAb and TBII levels were significantly associated to the clinical parameters of GO activity. TSAb was a more sensitive serological marker compared to TBII pertaining to eyelid retraction and edema, proptosis, extra-orbital muscle disorders, diplopia, irritable eye symptoms, and photophobia. TSAb, but not TBII, was a significant predictive marker of conjunctival redness, chemosis, caruncle/plica inflammation, eye irritation, and orbital pain, (odds ratio: 3.096, p = 0.016; 5.833, p = 0.009; 6.443, p = 0.020; 3.167, p = 0.045; 2.893, p = 0.032; versus 2.187, p = 0.093; 2.775, p = 0.081; 3.824, p = 0.055; 0.952, p = 0.930; 2.226, p = 0.099, respectively). Neither TSAb nor TBII correlated with the level of proptosis (ρ = 0.259, p = 0.090, and ρ = 0.254, p = 0.104, respectively), however rising TSAb levels were strongly associated to the level of proptosis.

CONCLUSIONS

TSH-R-Ab were significantly associated with GO's phenotype. Especially TSAb, as a sensitive and predictive serological biomarker, can improve diagnosis and management of GO.

The Role of Interleukin-17A and NLRP3 Inflammasome in the Pathogenesis of Graves' Ophthalmopathy

The development of Graves' ophthalmopathy (GO) is associated with autoimmune dysfunction. Recent studies have indicated that IL-17A, inflammasomes, and related cytokines may be involved in the etiology of GO. We sought to investigate the pathogenic role of IL-17A and NLRP3 inflammasomes in GO. Orbital fat specimens were collected from 30 patients with GO and 30 non-GO controls. Immunohistochemical staining and orbital fibroblast cultures were conducted for both groups. IL-17A was added to the cell cultures, and cytokine expression, signaling pathways, and inflammasome mechanisms were investigated using reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assay, Western blotting, and small interfering RNA (siRNA) methods. Immunohistochemical staining showed higher NLRP3 expression in GO orbital tissue than in non-GO controls. IL-17A upregulated pro-IL-1β mRNA levels and IL-1β protein levels in the GO group. Furthermore, IL-17A was confirmed to enhance caspase-1 and NLRP3 protein expression in orbital fibroblasts, suggesting NLRP3 inflammasome activation. Inhibiting caspase-1 activity could also decrease IL-1β secretion. In siRNA-transfected orbital fibroblasts, significantly decreased NLRP3 expression was observed, and IL-17A-mediated pro-IL-1β mRNA release was also downregulated. Our observations illustrate that IL-17A promotes IL-1β production from orbital fibroblasts via the NLRP3 inflammasome in GO, and cytokines subsequently released may induce more inflammation and autoimmunity.

Tea Polyphenols Reduce Inflammation of Orbital Fibroblasts in Graves' Ophthalmopathy via the NF-κB/NLRP3 Pathway

OBJECTIVE

This study aimed to explore the effects of tea polyphenols (TP) on inflammation of orbital fibroblasts in Graves' ophthalmopathy (GO) and to provide new ideas for GO treatment.

METHODS

Primary orbital fibroblasts were extracted from orbital adipose/connective tissues of patients with and without GO. Real-time quantitative PCR (RT-qPCR) was used to detect the expression of interleukin (IL)-6, IL-1β, and monocyte chemotactic protein (MCP)-1 in non-GO and GO orbital fibroblasts. The CCK-8 assay was used to determine the appropriate concentration of TP for subsequent experiments. RT-qPCR and enzyme-linked immunosorbent assay (ELISA) were performed to investigate the effects of TP on lipopolysaccharide (LPS)-induced production of inflammatory cytokines. Nuclear factor-κB (NF-κB) expression was measured using Western blotting analysis. NOD-like receptor 3 (NLRP3) expression was detected using both Western blotting analysis and immunofluorescence staining.

RESULTS

The mRNA levels of IL-6, IL-1β, and MCP-1 in GO orbital fibroblasts were significantly higher than those in non-GO cells. TP treatment significantly inhibited LPS-induced production of inflammatory factors, including IL-6, IL-1β, and MCP-1. TP also inhibited the expression levels of NF-κB and NLRP3. Inflammation in the GO orbital fibroblasts was higher than that in non-GO cells. TP inhibited the production of inflammatory cytokines in GO orbital fibroblasts in vitro through the NF-κB/NLRP3 pathway.

CONCLUSION

These findings suggest that TP may have a potential role in GO treatment.

The role of PET/CT in thyroid autoimmune diseases

Autoimmune thyroid diseases (AITD) are a heterogeneous group of disorders. They include, in particular, Graves' disease and Hashimoto's thyroiditis with a wide range of different functional status ranging from subclinical biochemical abnormalities to severe hyperthyroidism or severe hypothyroidism respectively. Furthermore, other conditions more frequently infectious or drug related can cause an immune reaction in the thyroid tissue. In AITDs, positron emission tomography/computed tomography (PET/CT) does not play a primary role for disease diagnosis or management, but accidental findings can occur in both symptomatic and asymptomatic patients, and they should be recognized and well interpreted. A comprehensive literature search of the PubMed databases was conducted to identify papers (systematic review, prospective and retrospective study, case report) evaluating the role of PET/CT in thyroid autoimmune diseases. Thyroid diffuse uptake of 18F-fluoro-2-deoxy-2-d-glucose ([18F]FDG) has been shown to be frequently associated with AITDs, but also with immune-induced thyroid disorders related to SARS-CoV-2 or immunotherapy, while malignant lesions more often have a focal aspect. Other radiopharmaceuticals as [68Ga]-DOTA-peptides, [68Ga]-fibroblast activation protein inhibitors (FAPIs) and [68Ga]-prostate specific membrane antigen ([68Ga]-PSMA) showed similar findings. In conclusion, PET/CT scan in AITDs does not play a primary role in the diagnosis, but the occasional finding of a thyroid uptake must always be described in the report and possibly investigated for a better patient's management.

Thicknesses of the retinal layers in patients with Graves' disease with or without orbitopathy

PURPOSE

Graves' orbitopathy (GO) is an inflammatory process that may involve the ocular surface, orbital fat, extraocular muscles, and optic nerves in patients with Graves' disease (GD). We aimed to compare thicknesses of retinal layers in patients with GD with and without GO.

METHODS

One hundred seven patients with GD [23 with GO (Group 1), 84 without GO (Group 2)] and eighteen volunteers (Group 3) were enrolled. The spectral-domain optical coherence tomography (SD-OCT) was used for ophthalmologic evaluation. Seven retinal layers including retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retinal pigment epithelium (RPE) were assessed. The thicknesses of layers were compared in groups.

RESULTS

The median GCL thickness values in groups 1, 2, and 3 were 14 µm, 15 µm, and 17.5 µm, respectively (p = 0.02). The median IPL thickness was 20 µm in group 1, 21 µm in group 2, and 22 µm in group 3 (p = 0.038). The median RPE thickness values in groups 1, 2, and 3 were 16 µm, 17 µm, and 18.5 µm, respectively (p = 0.001). GCL in group 1 was thinner than in group 3 (p = 0.02), while similar in groups 2 and 3 (p = 0.06). IPL in group 1 was thinner than in group 3 (p = 0.035), while similar in groups 2 and 3 (p = 0.13). RPE in groups 1 and 2 was thinner than in group 3 (p = 0.009, p = 0.001, respectively), while it was similar in groups 1 and 2 (p = 0.93). RNLF, INL, OPL, ONL were similar in all three (p > 0.05 for each).

CONCLUSION

Ganglion cell layer and IPL were thinner in patients with GO than in healthy controls, while both were similar in patients without GO and healthy controls. RPE was thinner in all Graves patients than in healthy controls. Early detection of changes in retinal layers of GD may guide the physician to prevent significant vision problems.

A randomized comparative study of inferomedial vs. balanced orbital decompression. Analysis of changes in orbital volume, eyelid parameters, and eyeball position

BACKGROUND/OBJECTIVES

The objective of this study is to investigate and compare changes in orbital volume, eyelid parameters, and eyeball position after inferomedial and balanced (medial + deep lateral walls) orbital decompression (OD) in patients with Graves' orbitopathy (GO).

SUBJECTS/METHODS

Prospective interventional trial. Forty-two patients with inactive GO and clinical indication for OD were randomly assigned to inferomedial or balanced OD. Preoperative and postoperative Hertel exophthalmometry, standardized photography, and computed tomography were used to evaluate upper and lower eyelid margin reflex distances (MRD₁ and MRD₂), orbital expansion, and changes in eyeball position.

RESULTS

Clinical and radiological exophthalmometry improved significantly after OD with both surgical techniques (p < 0.001), but more so with balanced OD (p = 0.02). Concurrent eyeball descent (p = 0.01) and orbital volume expansion (p < 0.001) were observed with both techniques. The mean decompression volume was similar for the medial wall and the lateral wall but significantly smaller for the inferior wall (p < 0.05). Significant correlation coefficients were found for Hertel reduction vs. total decompression volume (p < 0.05). In the multivariate linear analysis, lateral wall decompression volume (LWDV) was predictive of exophthalmos reduction (p < 0.05). The two techniques produced a similar reduction in MRD₁ and MRD₂. A significant correlation was also found between Hertel reduction and lower lid elevation (p < 0.05).

CONCLUSIONS

Both inferomedial and balanced OD successfully expanded orbit capacity, but the latter was more efficient at reducing exophthalmos probably due to the inclusion of the lateral wall. Upper and lower eyelid retraction improved after OD, but only lower eyelid elevation was correlated with exophthalmos reduction.

Efficacy and Safety of Different Intravenous Glucocorticoid Regimens in the Treatment of Graves' Ophthalmopathy: A Meta-Analysis

Purpose

The intravenous glucocorticoid (iv GC) represents the mainstay of therapy for Graves' ophthalmopathy (GO), but uncertainty remains concerning the optimal regimen. Although the European Group on Graves' Orbitopathy (EUGOGO) regimen has been commonly employed, evidence for its superiority to other regimens is still lacking. The aim of this meta-analysis was to compare the efficacy and safety of the EUGOGO regimen with higher-dose regimens in the management of GO.

Methods

A systematic review and meta-analysis of randomized controlled trials (RCTs) and cohort studies comparing the EUGOGO regimen with higher-dose regimens was conducted. PubMed, Embase, and Web of Science databases were searched for relevant studies. The efficacy outcomes were response rate, change in clinical activity score (CAS), rate of proptosis improvement, and retreatment rate. The safety outcome was the incidence of adverse events.

Results

In the five included eligible trials, 136 participants in the EUGOGO regimen and 177 participants in higher-dose regimens were evaluated. Compared with the EUGOGO regimen, higher-dose regimens had no beneficial effect on the response rate, change of CAS, rate of proptosis improvement, and retreatment rate (OR: 1.3; 95% CI: 0.36–4.65; SMD: –0.04; 95% CI: –0.54, 0.45; OR: 0.79; 95% CI: 0.44–1.44; OR: 0.87; 95% CI: 0.27–2.77). For the incidence of adverse events, the results also showed no significant difference between the 2 groups (OR: 1.14; 95% CI: 0.62–2.09).

Conclusion

The current evidence showed that the efficacy of the EUGOGO regimen was comparable with higher-dose regimens. Since there was no significant difference in the incidence of adverse events between the two regimens, appropriate selection of patients and careful monitoring were required in both regimens. More well-designed, large-scale, and longer follow-up period studies were needed to further verify the finding of this analysis.

Intravenous rituximab therapy for active Graves' ophthalmopathy: a meta-analysis

AIM

The successful treatment of Graves' ophthalmopathy (GO) remains a challenge, while the efficacy of rituximab (RTX) is at present controversial. The aim of this meta-analysis was to investigate the potential impact of intravenous RTX therapy in patients with GO.

METHODS

We performed a search in the PubMed, Embase, and Web of Science databases for relevant studies published before July 2020. The primary outcome was the change of clinical activity score (CAS), and secondary outcomes were the change of proptosis and TSH receptor antibodies (TRAb). A meta-analysis was conducted to calculate the standard mean difference (SMD) for these outcomes by using fixed- or random-effect models.

RESULTS

Analysis of outcomes in 152 patients collected from 12 published articles was conducted. Compared to baseline value, CAS was significantly decreased at 1, 6, 12, and >12 months after RTX treatment. For proptosis, the results revealed no significant decrease at 1-3, 6, and ≥12 months. Moreover, the pooled analysis employed in this meta-analysis showed no significant difference of TRAb at 1 month, but significant declines were observed at 6 and ≥12 months.

CONCLUSION

Our results strongly suggest that intravenous RTX treatment has an acute and long-lasting beneficial effect on decreasing both CAS and TRAb. The study also indicates that the effect of RTX on proptosis is limited. There is evidently a need to investigate the mechanism behind RTX ineffectiveness on proptosis and explore other therapeutic regimens for the reduction of proptosis.

Teprotumumab: The Dawn of Therapies in Moderate-to-Severe Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is a potentially sight-threatening ocular disease. About 3-5% of patients with TAO have severe disease with intense pain, inflammation, and sight-threatening corneal ulceration or compressive optic neuropathy. The current treatments of TAO are often suboptimal, mainly because the existing therapies do not target the pathogenesis of the disease. TAO mechanism is unclear. Ocular fibrocytes express relatively high levels of the functional TSH receptor (TSHR), and many indirect evidences support its participation. Over expression of insulin-like growth factor-1 receptor (IGF-IR) in fibroblasts, leading to inappropriate expression of inflammatory factors, production of hyaluronic acid and cell activation in orbital fibroblasts are also possible mechanisms. IGF-1R and TSHR form a physical and functional signaling complex. Inhibition of IGF-IR activity leads to the attenuation of signaling initiated at either receptor. Teprotumumab (TMB) is a human immunoglobulin G1 monoclonal antibody, binding to IGF-IR. Recently two TMB clinical trials had been implemented in TAO patients, indicating dramatic reductions in disease activity and severity, which approved its use for the treatment of TAO in the US. This review summarizes the treatments of TAO, focusing on the pathogenesis of IGF-1R in TAO and its application prospects.

Simvastatin Inhibits CYR61 Expression in Orbital Fibroblasts in Graves' Ophthalmopathy through the Regulation of FoxO3a Signaling

Graves' ophthalmopathy (GO), which is characterized by orbital tissue inflammation, expansion, and fibrosis, is the ocular manifestation in 25% to 50% of patients with Graves' disease. As the pathology of GO is driven by autoimmune inflammation, many proinflammatory cytokines/chemokines, including TNF-α, IL-1β, IL-6, and CCL20, are crucial in the pathogenesis of GO to activate the orbital fibroblasts. Cysteine-rich protein 61 (CYR61), which is known to regulate cell proliferation, adhesion, and migration, plays a proinflammatory role in the pathogenesis of many inflammatory diseases, such as rheumatoid arthritis. CYR61 was considered a potential biomarker of GO in recent studies. Statins, which are cholesterol-lowering drugs, were found to reduce the risk of GO, probably through their anti-inflammatory and immunomodulatory effects. In this study, we established a link between CYR61 and statins in the pathogenesis and potential treatment for GO. Firstly, our data showed the overexpression of CYR61 in the orbital tissue (n = 4) and serum specimens (n = 6) obtained from the patients with inactive GO. CYR61 could induce the production of IL-6 and CCL20 in cultured GO orbital fibroblasts. The expression of CYR61 in cultured GO orbital fibroblasts was upregulated via TNF-α stimulation. Secondly, we pretreated cultured GO orbital fibroblasts using simvastatin, a statin, followed by TNF-α stimulation. The data revealed that simvastatin could inhibit TNF-α-induced CYR61 expression by modulating the activity of transcription factor FoxO3a. Our results provided insights into some cellular mechanisms that may explain the possible protective effects of simvastatin against the development of GO.

Insulin-Like Growth Factor Pathway and the Thyroid

The insulin-like growth factor (IGF) pathway comprises two activating ligands (IGF-I and IGF-II), two cell-surface receptors (IGF-IR and IGF-IIR), six IGF binding proteins (IGFBP) and nine IGFBP related proteins. IGF-I and the IGF-IR share substantial structural and functional similarities to those of insulin and its receptor. IGF-I plays important regulatory roles in the development, growth, and function of many human tissues. Its pathway intersects with those mediating the actions of many cytokines, growth factors and hormones. Among these, IGFs impact the thyroid and the hormones that it generates. Further, thyroid hormones and thyrotropin (TSH) can influence the biological effects of growth hormone and IGF-I on target tissues. The consequences of this two-way interplay can be far-reaching on many metabolic and immunologic processes. Specifically, IGF-I supports normal function, volume and hormone synthesis of the thyroid gland. Some of these effects are mediated through enhancement of sensitivity to the actions of TSH while others may be independent of pituitary function. IGF-I also participates in pathological conditions of the thyroid, including benign enlargement and tumorigenesis, such as those occurring in acromegaly. With regard to Graves' disease (GD) and the periocular process frequently associated with it, namely thyroid-associated ophthalmopathy (TAO), IGF-IR has been found overexpressed in orbital connective tissues, T and B cells in GD and TAO. Autoantibodies of the IgG class are generated in patients with GD that bind to IGF-IR and initiate the signaling from the TSHR/IGF-IR physical and functional protein complex. Further, inhibition of IGF-IR with monoclonal antibody inhibitors can attenuate signaling from either TSHR or IGF-IR. Based on those findings, the development of teprotumumab, a β-arrestin biased agonist as a therapeutic has resulted in the first medication approved by the US FDA for the treatment of TAO. Teprotumumab is now in wide clinical use in North America.

[Influence of CYP3A4, CYP3A5, and NR3C1 genes polymorphism on the effectiveness of glucocorticoid therapy in patients with endocrine ophthalmopathy]

For more than 60 years, glucocorticoid therapy has been practically the only method for treating patients with endocrine ophthalmopathy - non-specific autoimmune inflammation of the soft tissues of the orbit. Steroid-resistant forms of this disease are known to exist. The reasons for the formation of glucocorticoid resistance are not fully understood yet.

PURPOSE

To study the possibilities of pharmacogenetic testing for the polymorphism of the glucocorticoid receptor gene NR3C1 and cytochrome P450 in predicting the effectiveness of glucocorticoid therapy in patients with edematous exophthalmos - one of the clinical forms of endocrine ophthalmopathy.

MATERIAL AND METHODS

The results of glucocorticoid therapy were analyzed in 75 patients with different clinical forms of endocrine ophthalmopathy aged 27 to 84 years. All patients underwent standard ophthalmological examination, external examination of the eye with assessment of the state of periorbital tissues, determination of the shape and size of the palpebral fissure (vertical size), position of the eye in orbit, Hertel exophthalmometry, ultrasound scanning and computed tomography of the orbits. Genetic analysis of the polymorphism of the studied genes was carried out using real-time polymerase chain reaction (real-time PCR).

RESULTS

The study did not find patterns in the distribution of homo- and heterozygous genotypes of A6986G polymorphic markers of the CYP3A5 gene, 6 C>T intron of the CYP3A4 gene and rs6190 of the NR3C1 gene in patients with endocrine ophthalmopathy and their effect on the glucocorticoid response (p>0.05).

CONCLUSION

Results of pharmacogenetic testing of the gene for the glucocorticoid receptor NR3C1 and cytochrome P450 do not provide a reliable confirmation of the influence of the polymorphism of the studied genes on the effectiveness of glucocorticoid therapy in patients with endocrine ophthalmopathy.

Non-EPI-DWI for Detection, Disease Monitoring, and Clinical Decision-Making in Thyroid Eye Disease

BACKGROUND AND PURPOSE

The Clinical Activity Score is widely used to grade activity of thyroid eye disease and guide treatment decisions, but as a subjective measurement and being confined to the anterior orbit, it has limitations. Non-EPI-DWI of the extraocular muscles may offer advantages as a functional imaging technique with reduced skull base artifacts, but the correlation with the Clinical Activity Score and patient outcome is unknown. Our aim was to establish the correlation between the Clinical Activity Score and non-EPI-DWI and to describe the additional value provided by adjunctive non-EPI-DWI in making clinical decisions.

MATERIALS AND METHODS

This was a retrospective longitudinal study of 31 patients seen in a multidisciplinary thyroid eye disease clinic during 5 years who had at least 1 ophthalmic and endocrine assessment including the Clinical Activity Score and a non-EPI-DWI ADC calculation. The Spearman rank correlation coefficient was used to determine the relationship between the Clinical Activity Score and non-EPI-DWI. A patient flow chart was constructed to evaluate clinical decision-making, and receiver operating characteristics were generated.

RESULTS

From 60 non-EPI-DWI scans, 368 extraocular muscles were selected for analysis. There was a significant positive correlation between the Clinical Activity Score and ADC (r _s = 0.403; 95% CI, 0.312-0.489; P < .001). ADC values were significantly higher in the Clinical Activity Score ≥ 3 group compared with the Clinical Activity Score < 3 group (P < .001). Our patient flow chart identified a third intermediate-severity cohort in which the non-EPI-DWI was particularly useful in guiding clinical decisions.

CONCLUSIONS

The non-EPI-DWI correlated well with the Clinical Activity Score in our patients and was a useful adjunct to the Clinical Activity Score in making clinical decisions, especially in patients with intermediate activity and severity of thyroid eye disease.

Histogram analysis of T2 mapping for detecting early involvement of extraocular muscles in patients with thyroid-associated ophthalmopathy

Using histogram analysis of T2 values to detect early involvement of extraocular muscles (EOMs) in patients with thyroid-associated ophthalmopathy (TAO). Five EOMs of each orbit were analyzed for 45 TAO patients and 22 healthy controls (HCs). Patients’ EOMs were grouped into involved or normal-appearing EOMs (NAEOMs). Histogram parameters and signal intensity ratios (SIRs) of EOMs were compared; receiver operating characteristic (ROC) curve analysis was performed to differentiate NAEOMs from EOMs of HCs. 24 patients were reassessed following immunosuppressive treatment. For SIRs, involved muscles showed higher values than those of NAEOMs and HCs (p < 0.05); there were no differences between NAEOMs and HCs (p = 0.26). Parameters of involved muscles showed no different from those of NAEOMs excluding 25th, 50th percentiles, and standard deviation (SD) (p < 0.05). NAEOMs displayed higher values of 90th, 95th percentiles, SD, skewness, inhomogeneity, and entropy than HCs (p < 0.05). ROC curve analysis of entropy yielded the best area under the ROC curve (AUC; 0.816) for differentiating NAEOMs and HCs. After treatment, histogram parameters including 5th, 75th, 90th, and 95th percentiles, SD, kurtosis, inhomogeneity, and entropy were reduced in NAEOMs (p < 0.05). T2 histogram analysis could detect early involvement of EOMs in TAO prior to detection on conventional orbital MRI.

Novel Roles of Chloroquine and Hydroxychloroquine in Graves' Orbitopathy Therapy by Targeting Orbital Fibroblasts

CONTEXT

Graves' orbitopathy (GO) causes infiltrative exophthalmos by inducing excessive proliferation, adipogenesis, and glycosaminoglycan production in orbital fibroblasts (OFs). Interference with OF autophagy is a potential therapy for proptosis.

OBJECTIVES

Here, we aimed to evaluate the effects of chloroquine (CQ) and hydroxychloroquine (HCQ), the autophagy inhibitors commonly used in clinical practice, on OFs.

DESIGN/SETTING/PARTICIPANTS

OFs isolated from patients with GO (GO-OFs) or control individuals (non-GO-OFs) were cultured in proliferation medium (PM) or subjected to differentiation medium. OFs were treated with CQ or HCQ (0, 0.5, 2, and 10 μM), and subsequently examined in vitro.

MAIN OUTCOME MEASURES

CCK-8, EdU incorporation, and flow cytometry assays were used to assess cellular viability. Adipogenesis was assessed with Western blot analysis, real-time polymerase chain reaction (PCR) , and Oil Red O staining. Hyaluronan production was determined by real-time PCR and enzyme-linked immunosorbent assay. Autophagy flux was detected through red fluorescent protein (RFP)-green fluorescent protein (GFP)-LC3 fluorescence staining and Western blot analyses.

RESULTS

CQ/HCQ halted proliferation and adipogenesis in GO-OFs in a concentration-dependent manner through blockage of autophagy, phenotypes that were not detected in non-GO-OFs. The inhibitory effect of CQ/HCQ on hyaluronan secretion of GO-OFs was also concentration dependent, mediated by downregulation of hyaluronan synthase 2 rather than hyaluronidases. Moreover, CQ (10 μM) induced GO-OF apoptosis without aggravating oxidative stress.

CONCLUSIONS

The antimalarials CQ/HCQ affect proliferation, adipogenesis, and hyaluronan generation in GO-OFs by inhibiting autophagy, providing evidence that they can be used to treat GO as autophagy inhibitors.

Thyroid eye disease: current and potential medical management

INTRODUCTION

Thyroid eye disease (TED) is the most frequent extra-thyroid manifestation of Graves' disease and it is more frequent in middle age and in female gender. Nowadays, the causal mechanisms of this disease are not completely understood, but the current available studies suggest that the main causative factor is the thyroid stimulating hormone receptor.

MATERIALS AND METHODS

To collect reports on TED medical management, a thorough literature search was performed in PubMed database. An additional search was made in Google Scholar to complete the collected items.

RESULTS

Among the indentified risk factors, tobacco habit is the most relevant. The main criteria to choose a suitable treatment are the activity and severity of the disease. Support measures can be used to improve the patient's symptoms in any phase of the disease. There is a large number of drugs proposed to manage TED, although with different reported rates of success.

CONCLUSIONS

Currently, the drugs of choice are corticosteroids in moderate-to-severe and in sight-threatening forms. The main problem of corticosteroids is their spectrum of side effects. Therefore, other alternatives are being suggested for medical management of this disease. The efficacy of these alternatives remains unclear.

Novel therapies for thyroid autoimmune diseases: An update

A Th1 immune-preponderance has been shown in the immunopathogenesis of autoimmune thyroiditis (AT), Graves' disease (GD) and Graves' Ophthalmopathy (GO), in which the Th1-chemokines (CXCL9, CXCL10, CXCL11), and their (C-X-C)R3 receptor, have a crucial role. Methimazole, and corticosteroids have been shown to modulate these chemokines; several efforts have been done to modulate the autoimmune reaction with other drugs, i.e. PPAR-γ, or -α ligands, or antibodies, or small molecules directed against CXCL10, or CXCR3. Antigen-specific therapy for GD, by inducing T cell tolerance through an immunization with TSH-R peptides, has been published. Drugs targeting cytokines [anti-TNFα (Etanercept), and anti-IL-6 (Tocilizumab)], and RTX (a chimeric monoclonal antibody vs. CD20) have been used in GO, with promising results. Teprotumumab (a human monoclonal anti-IGF-1R blocking antibody) has been investigated in a trial, showing it was very effective in GO patients. Still, more studies are needed for new therapies targeting autoimmune thyroid disorders.

Simvastatin and ROCK Inhibitor Y-27632 Inhibit Myofibroblast Differentiation of Graves' Ophthalmopathy-Derived Orbital Fibroblasts via RhoA-Mediated ERK and p38 Signaling Pathways

Transforming growth factor-β (TGF-β)-induced differentiation of orbital fibroblasts into myofibroblasts is an important pathogenesis of Graves' ophthalmopathy (GO) and leads to orbital tissue fibrosis. In the present study, we explored the antifibrotic effects of simvastatin and ROCK inhibitor Y-27632 in primary cultured GO orbital fibroblasts and tried to explain the molecular mechanisms behind these effects. Both simvastatin and Y-27632 inhibited TGF-β-induced α-smooth muscle actin (α-SMA) expression, which serves as a marker of fibrosis. The inhibitory effect of simvastatin on TGF-β-induced RhoA, ROCK1, and α-SMA expression could be reversed by geranylgeranyl pyrophosphate, an intermediate in the biosynthesis of cholesterol. This suggested that the mechanism of simvastatin-mediated antifibrotic effects may involve RhoA/ROCK signaling. Furthermore, simvastatin and Y-27632 suppressed TGF-β-induced phosphorylation of ERK and p38. The TGF-β-mediated α-SMA expression was suppressed by pharmacological inhibitors of p38 and ERK. These results suggested that simvastatin inhibits TGF-β-induced myofibroblast differentiation via suppression of the RhoA/ROCK/ERK and p38 MAPK signaling pathways. Thus, our study provides evidence that simvastatin and ROCK inhibitors may be potential therapeutic drugs for the prevention and treatment of orbital fibrosis in GO.

Insulin-like Growth Factor-I Receptor and Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is a complex disease process presumed to emerge from autoimmunity occurring in the thyroid gland, most frequently in Graves disease (GD). It is disfiguring and potentially blinding, culminating in orbital tissue remodeling and disruption of function of structures adjacent to the eye. There are currently no medical therapies proven capable of altering the clinical outcome of TAO in randomized, placebo-controlled multicenter trials. The orbital fibroblast represents the central target for immune reactivity. Recent identification of fibroblasts that putatively originate in the bone marrow as monocyte progenitors provides a plausible explanation for why antigens, the expressions of which were once considered restricted to the thyroid, are detected in the TAO orbit. These cells, known as fibrocytes, express relatively high levels of functional TSH receptor (TSHR) through which they can be activated by TSH and the GD-specific pathogenic antibodies that underpin thyroid overactivity. Fibrocytes also express insulin-like growth factor I receptor (IGF-IR) with which TSHR forms a physical and functional signaling complex. Notably, inhibition of IGF-IR activity results in the attenuation of signaling initiated at either receptor. Some studies suggest that IGF-IR-activating antibodies are generated in GD, whereas others refute this concept. These observations served as the rationale for implementing a recently completed therapeutic trial of teprotumumab, a monoclonal inhibitory antibody targeting IGF-IR in TAO. Results of that trial in active, moderate to severe disease revealed dramatic and rapid reductions in disease activity and severity. The targeting of IGF-IR with specific biologic agents may represent a paradigm shift in the therapy of TAO.

Management of Patients with Graves' Disease and Orbital Involvement: Role of Spectral Domain Optical Coherence Tomography

Purpose

To investigate the role of choroidal thickness evaluation with spectral domain optical coherence tomography (SDOCT) and enhanced depth imaging (EDI) technique in the management of patients with Graves' disease and orbitopathy (GO).

Methods

Thirty-six eyes of 18 patients with GO and 36 eyes of 18 age-matched control subjects were included in this retrospective observational study. All the subjects underwent a complete ophthalmological evaluation, including clinical activity score (CAS) and exophthalmometry. The SDOCT images of the choroid were obtained by EDI modality.

Results

Choroidal thickness was significantly increased in GO than in control eyes (p < 0.01). A significant correlation was found between choroidal thickness and CAS, proptosis, and the duration of disease (p < 0.05).

Conclusion

This study shows that choroidal thickness, evaluated with EDI-OCT, is significantly increased in patients with GO and correlates with the activity of the disease, proptosis, and duration of the disease. The choroidal thickening may reflect the ocular hemodynamic changes, and enhanced depth imaging optical coherence tomography may be a useful tool for the evaluation of orbital congestion and management of patients with Graves' disease and orbital involvement.

Does rituximab improve clinical outcomes of patients with thyroid-associated ophthalmopathy? A systematic review and meta-analysis

BACKGROUND

The current therapies of thyroid-associated ophthalmopathy (TAO) were still a challenging matter. In this study, we aimed to contrast the impact of before- after rituximab (RTX) therapy in the patients with TAO.

METHODS

We searched the PubMed, EMBASE, and SCOPUS databases for articles published up to July 3, 2017. Fixed- or random-effects meta-analysis was used to provide pooled estimates of standard mean difference (SMD) both the primary outcome from clinical activity score (CAS), and secondary outcomes from thyrotropin receptor antibody (TRAb), proptosis, thyroid stimulating hormone (TSH), and interleukin-6 (IL-6) levels. In addition, the quality and each study was assessed using either the Newcastle Ottawa Scale (NOS) or the Cochrane Risk of Bias tool, and reliability of the meta-analytic result using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Of the 839 articles initially searched, 11 studies were finally eligible for inclusion. Subgroup analysis results showed that comparing with initial value, there was a decline in CAS at 1,3,6,12 month after RTX treatment, decreased TRAbs level at 6,12 month, proptosis improvement at least 1 month, unchanged IL-6 level at 6 month, decreased TSH level at 3 month but unchanged at 12 month. All included studies were classified as good quality.

CONCLUSIONS

The pooled data suggested that the preliminary effects of RTX treatment on TAO might be promising. However, more large-sample and high-quality studies targeting RTX use during this disease and long-term surveillance of prognosis are urgently needed.

Astragaloside IV attenuates orbital inflammation in Graves' orbitopathy through suppression of autophagy

INTRODUCTION

Graves' orbitopathy (GO) is an autoimmune inflammatory disorder affecting the orbit around the eye. Astragaloside IV (AS-VI) is the main active ingredient of the Chinese herbal medicine Huangqi (Radix Astragali Mongolici). AS-IV exhibits antioxidant and anti-inflammatory properties, and shows therapeutic potential in a number of ischemic and inflammatory diseases; however, its pharmaceutical activities in GO remain undefined.

MATERIALS AND METHODS

In this study, we investigated the effects of AS-IV on interleukin (IL)-1β-induced orbital fibroblast inflammation in vitro and GO orbital inflammation and ocular histopathological changes in vivo, as well as the underlying mechanisms responsible for these effects.

RESULTS AND CONCLUSION

The results show that IL-1β increased mRNA expression of the inflammatory cytokines IL-6, IL-8, TNF-α, and MCP-1 in cultured orbital fibroblasts. This IL-1β-induced inflammation was accompanied by increased autophagic activity as reflected in increased Beclin-1 and Agt-5 expression, as well as LC3-I to LC3-II conversion. Pretreatment with the autophagy inhibitors 3-MA and bafilomycin A1, or silencing of autophagy-related proteins Beclin-1 and Atg-5, prevented IL-1β-induced orbital fibroblast inflammation, while pretreatment with the autophagy activator rapamycin had the opposite effects. These data suggested that autophagy was involved in GO orbital inflammation. AS-IV treatment significantly decreased IL-1β-induced inflammatory cytokine production in orbital fibroblasts in vitro and attenuated GO orbital inflammation, fat accumulation, collagen deposition, and macrophage infiltration in vivo. These in vitro and in vivo protective effects of AS-IV against GO were accompanied by decreased autophagic activities in orbital fibroblasts and GO orbital tissues, respectively. Collectively, our findings suggested that AS-IV protects against GO through suppression of autophagy. Thus, AS-IV may have preventive benefits for GO.

Non-surgical treatment for eyelid retraction in thyroid eye disease (TED)

Thyroid eye disease (TED) is an autoimmune condition with an unpredictable course that may lead to permanent facial disfigurement. Eyelid retraction is one of the most common findings, and frequently demands attention due to ocular exposure and impaired cosmesis. Surgical treatment remains the most effective option, but there is a role for temporary corrections during the active phase of the disease, as well as in patients who are poor surgical candidates. The aim of this review is to describe the non-surgical modalities currently available for treatment of eyelid malposition in TED. The authors have focused on the use of hyaluronic acid, triamcinolone injections and botulinum toxin type A as non-surgical treatment alternatives, paying special attention to dosing, technique, efficacy and duration of effect. Non-surgical treatment modalities may represent viable in cases where surgical correction is not an option. Although temporary, these modalities appear to be beneficial for ocular exposure remediation, improving quality of life and broadening our therapeutic arsenal.

Orbital fibroblasts of Graves' orbitopathy stimulated with proinflammatory cytokines promote B cell survival by secreting BAFF

The success of rituximab for the treatment of active Graves' orbitopathy (GO) suggests that B cells play a critical role in intraorbital inflammation. B cell activating factor (BAFF) and its homolog a proliferation-inducing ligand (APRIL) are critical for B cell survival. However, the contribution of BAFF/APRIL to GO remains unclear. We sought to determine the role of BAFF/APRIL in the orbits of GO, and found that BAFF was markedly upregulated, while APRIL was not. Additionally, cultured GO orbital fibroblasts (GO-OFs)² expressing BAFF were induced to produce a large amount of BAFF. In contrast, a weak APRIL expression was detected in the OFs, and they exhibited a slight response to stimulation. Notably, pretreated GO-OFs promoted B cell survival, and this effect was significantly inhibited by a BAFF-R neutralizing antibody. This study indicates that OFs from GO can express BAFF and mediate the intraorbital survival of B cells via BAFF mechanism.

Icariin Inhibits AMPK-Dependent Autophagy and Adipogenesis in Adipocytes In vitro and in a Model of Graves' Orbitopathy In vivo

Graves' orbitopathy (GO), an extrathyroidal manifestation of Graves' disease, is an inflammatory autoimmune disorder of the orbit that involves the differentiation of precursor cells into mature adipocytes and retro-orbital adipose tissue accumulation. Here, we examined the involvement of autophagy in adipogenesis and explored the effects of icariin, a flavonoid isolated from the genus Epimedium with a wide range of biological and pharmacological effects, on autophagy and adipogenesis in 3T3-L1 preadipocytes and in a mouse model of GO. Microscopic examination of autophagosome formation and lipid droplet accumulation by Oil Red O staining, and western blot assessment of autophagic markers in the presence of the autophagy inhibitors Asn and 3-MA showed that autophagy is essential for adipogenesis. Icariin inhibited the differentiation of preadipocytes into mature adipocytes by suppressing autophagy, and these effects were mediated by the inhibition of AMPK/mTOR pathway activation. In a mouse model of thyroid stimulating hormone receptor induced GO, icariin reduced orbital muscle adipose tissue expansion and lipid droplet accumulation by inhibiting AMPK/mTOR mediated autophagy. Collectively, these results reveal a potential mechanism underlying the protective effects of icariin against autophagy induced adipogenesis and suggest that icariin could be developed as a new therapeutic candidate for the prevention and treatment of GO.

Comparison of Early Total Thyroidectomy with Antithyroid Treatment in Patients with Moderate-Severe Graves' Orbitopathy: A Randomized Prospective Trial

BACKGROUND

The optimal therapeutic choice for Graves' hyperthyroidism in the presence of moderate-severe Graves' orbitopathy (GO) remains controversial.

OBJECTIVES

We aimed to compare GO course in patients with moderate-severe GO treated with early total thyroidectomy (TTx) versus antithyroid drug (ATD) regimens, in a prospective, randomized manner.

METHODS

Forty-two patients with moderate-severe GO were enrolled. A total of 4.5 g of pulse corticosteroids were given intravenously to all patients before randomization. Patients in the first group were given TTx, whereas patients in the second group were treated with ATDs. TSH was kept between 0.4 and 1 mIU/l. The clinical course of GO was evaluated with proptosis, lid aperture, clinical activity score (CAS), and diplopia.

RESULTS

Eighteen and 24 patients were randomized to the TTx and ATD groups, respectively. Thyroid autoantibodies decreased significantly, and there were significant improvements in proptosis, lid aperture, and CAS in the TTx group. While in the ATD group the decrement in thyroid autoantibodies was not significant, there were significant improvements in proptosis and CAS. When the TTx group was compared with the ATD group, anti-TPO, anti-Tg, and TSH-receptor antibodies were significantly decreased in the TTx group (p < 0.01), but there was no significant difference with respect to proptosis, lid aperture, CAS, and diplopia between the two groups during a median (min.-max.) follow-up period of 60 months (36-72).

CONCLUSION

Although no definitive conclusions could be drawn from the study, mainly due to limited power, early TTx and the ATD treatment regimens, followed by intravenous pulse corticosteroid therapy, seemed to be equally effective on the course of GO in this relatively small group of patients with moderate-severe GO during a median (min.-max.) follow-up period of 60 months (36-72).

Novel Therapies for Thyroid Autoimmune Diseases

C-X-C chemokine receptor (CXCR)3 and its interferon(IFN)γ-dependent chemokines (CXCL10, CXCL9, CXCL11) are implicated in the immune-pathogenesis of autoimmune thyroiditis (AT), Graves disease (GD) and Graves Ophthalmopathy (GO). In tissue, recruited Th1 lymphocytes produce IFNγ, enhancing the tissue secretion of IFNγ-inducible chemokines, initiating and perpetuating the autoimmune process. Patients with AT (with hypothyroidism), and with GO and GD, particularly in the active phase, have high IFNγ-inducible chemokines. Peroxisome proliferator-activated receptor (PPAR)γ or -α agonists and methimazole exert an immune-modulation on CXCR3 chemokines in AT, GD and GO. Other studies are ongoing to evaluate new molecules acting as antagonists of CXCR3, or blocking CXCL10, in Hashimoto thyroiditis (HT), GD and GO. Recently, novel molecules targeting the various agents involved in the pathogenesis of GO, such as rituximab, have been proposed as an alternative to corticosteroids. However, randomized and controlled studies are needed to generalize these interesting results.

Inhibitory Effects of α-Lipoic Acid on Oxidative Stress-Induced Adipogenesis in Orbital Fibroblasts From Patients With Graves Ophthalmopathy

A choice of the optimal treatment for Graves ophthalmopathy (GO) is a challenge due to the complexity of the pathogenesis. Alpha-lipoic acid (ALA) is well known as a multifunctional antioxidant, helping to protect cells against oxidative stress and inflammatory damage.The aim of this study was to investigate the effects of ALA on intracellular production of reactive oxygen species (ROS), inflammation, and adipogenesis using primary cultured orbital fibroblasts from patients with GO.Intracellular ROS levels and mRNA expressions of proinflammatory cytokines and chemokines including intercellular adhesion molecule-1 (ICAM-1), interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, and regulated upon activation normal T cell expressed and presumably secreted (RANTES) were measured. After adipogenesis, the expressions of peroxisome proliferator-activated receptor (PPAR)γ, CCAAT-enhancer-binding proteins (C/EBP)α and β, and heme oxygenase-1 (HO-1) were investigated.H2O2 dose-dependently stimulated ROS production and HO-1 expression. Addition of ALA strongly attenuated ROS production and further increased HO-1 expression. However, by pretreatment of zinc protoporphyrin (ZnPP), HO-1 inhibitor, ALA inhibition of ROS generation by H2O2 was abolished. Tumor necrosis factor (TNF)α-induced mRNA expressions of ICAM-1, IL-6, MCP-1, and RANTES were inhibited by ALA treatment. In this context, TNFα-induced phosphorylation of P65 was also inhibited. In addition, ALA dose-dependently inhibited H2O2-induced intracellular accumulation of lipid droplets. The expression of adipogenic transcription factors, including PPARγ, C/EBPα, and β, was also inhibited.ALA is a potential therapeutic agent for GO because of the inhibitory effects on ROS production and gene expression of proinflammatory cytokines and chemokines, resulting in prevention of adipose-tissue expansion.

Genetic Associations of Interleukin-related Genes with Graves' Ophthalmopathy: a Systematic Review and Meta-analysis

Graves’ ophthalmopathy (GO) is the commonest extra-thyroidal manifestation of Graves’ disease (GD). Associations between interleukin-related (IL) gene polymorphisms and GO have been reported in different populations. We aim to confirm such associations by conducting a meta-analysis. Totally 382 publications were retrieved in MEDLINE and EMBASE up to 25/2/2015. After removing the duplicates and assessing the studies, we retrieved 16 studies that met the selection criteria for meta-analysis, involving 12 polymorphisms in 8 IL-related genes, and 1650 GO cases and 2909 GD controls. The summary odds ratio (OR) and 95% confidence intervals (CI) were estimated. We found one polymorphism in IL1A (rs1800587, c.-889C>T) showing a suggestive association with GO in the meta-analysis (allelic model [T vs. C]: OR = 1.62, 95% CI: 1.00–2.62, P = 0.050, I² = 53.7%; recessive model [TT vs. TC + CC]: OR = 2.39, 95% CI: 1.07–5.37, P = 0.039, I² = 23.6%; heterozygous model [TC vs. CC]: OR = 1.52, 95% CI: 1.04–2.22, P = 0.034, I² = 37.0%). No association with GO was detected for the other 7 genes (IL1B, IL1RA, IL4, IL6, IL12B, IL13 and IL23R). Our results thus indicate that IL1A is likely to be a genetic biomarker for GO. Further studies with larger sample sizes are warranted to confirm the associations of IL1A and other IL-related genes with GO.

Total thyroid ablation in Graves' orbitopathy

Graves' orbitopathy (GO) is an autoimmune condition almost always associated with autoimmune thyroid disease, especially Graves' disease (GD). According to the most widely accepted model, the autoantigens responsible for GO would include molecules expressed by thyroid epithelial cells that are present also in orbital tissues. The high likelihood that the etiologies of GO and of the underlying autoimmune thyroid diseases are somehow linked is confirmed by the very close relationship between GO, the onset and the course of Graves' diseases, the size of the thyroid gland, and most importantly, thyroid function and thyroid treatment. Based on these considerations, it has been proposed that complete removal of thyroid antigens and of thyroid infiltrating lymphocytes, the so-called total thyroid ablation (TTA), may be followed by an attenuation of the immune reaction against orbital antigens, and ultimately by an amelioration of GO. The possibility that TTA, achieved by near total thyroidectomy followed by radioiodine, may be beneficial for GO was initially suggested by two retrospective studies and more recently by two prospective, randomized clinical trials conducted in patients with moderate GO treated with intravenous glucocorticoids. Although there seemed to be no difference in the long term, compared with near total thyroidectomy alone TTA was associated with a shorter time required for GO to improve, or anyway to reach its best possible outcome, and with a lesser requirement for additional treatments for GO to improve. Whether this is sufficient to offer ablation to patients remains a matter of discussion. At present, this procedure could be offered only to patients scheduled to thyroidectomy and glucocorticoid treatment.

Commentary: rituximab, adalimumab, etanercept, tocilizumab--are biologics the future for Graves' orbitopathy?

Graves' orbitopathy (GO) is the main extrathyroidal manifestation of Graves disease and a rare disease in its severe expressions. Moderate-to-severe GO represents a therapeutic challenge. Established nonsurgical treatments include glucocorticoids (most commonly given intravenously), cyclosporine, and orbital radiotherapy. However, results are not always satisfactory, and a relevant proportion of GO patients need some kind of rehabilitative surgery (orbital decompression, squint surgery, eyelid surgery) once GO is inactivated. Biological agents have been used in several autoimmune disorders, with contrasting results. Current better understanding of the pathogenesis of GO allows us to identify pathways that might be the target of biologics. T and B cells, cytokines, and peroxisome proliferator-activated receptor-γ might all be targeted by treatments. It is extremely difficult to design and perform sufficiently powered randomized controlled studies that may support the role of targeted therapies. For the time being, rituximab, a monoclonal antibody depleting CD20-positive B cells, appears the most promising agent, but so far its use relies on the results of small and uncontrolled studies.

Efficacy of B-cell targeted therapy with rituximab in patients with active moderate to severe Graves' orbitopathy: a randomized controlled study

BACKGROUND

Preliminary studies have shown that rituximab (RTX) is effective in the treatment of active Graves' orbitopathy (GO).

METHODS

We conducted a double-blind, randomized trial (European Clinical Trials Database [EudraCT] 2007-003910-33) to compare RTX with iv methylprednisolone (ivMP) in patients with active moderate to severe GO. Thirty-two patients were randomized to receive either ivMP (7.5 g) or RTX (2000 or 500 mg). The primary end point was the decrease of the clinical activity score of 2 points or to less than 3 at week 24. Changes of proptosis, lid fissure, diplopia and eye muscle motility, and quality of life score were secondary end points. The number of therapeutic responses, disease reactivation, and surgical procedures required during follow-up and the patients' quality of life were also assessed.

RESULTS

The clinical activity score decreased with both treatments but more after RTX at 16, 20, and 24 weeks (P < .04, P < .02, P < .006, respectively), whether 1000 mg RTX twice or 500 mg RTX once was used (P = NS). At 24 weeks 100% of RTX patients improved compared with 69% after ivMP (P < .001). Disease reactivation was never observed in RTX patients but was observed in five after ivMP. Patients treated with RTX scored better motility at 52 weeks in both the right (P = .014) and the left eye (P = .026). Overall rehabilitative surgical procedures carried out during follow-up (at 76 wk) were 12 in 16 ivMP patients and 5 in 15 RTX patients (P = .049).

CONCLUSIONS

The results of this trial confirm preliminary reports on a better therapeutic outcome of RTX in active moderate to severe GO, when compared with ivMP, even after a lower RTX dose. The better eye motility outcome, visual functioning of the quality of life assessment, and the reduced number of surgical procedures in patients after RTX seem to suggest a disease-modifying effect of the drug.

Efficacy of Subantimicrobial Dose Doxycycline for Moderate-to-Severe and Active Graves' Orbitopathy

Aim. To study the efficacy and safety of subantimicrobial dose (SD) doxycycline(50 mg/d) in patients with active and moderate-to-severe Graves' orbitopathy (GO). Methods. Thirteen patients with active and moderate-to-severe GO received once daily oral doxycycline (50 mg/d) for 12 wk. Treatment response at 24 wk was used as the primary outcome, measured by a composite of improvement in Clinical Activity Score (CAS), diplopia, motility, soft tissue swelling, proptosis, and eyelid aperture. Secondary outcome was the change of quality of life score (QoL, including visual functioning subscale and appearance subscale). Adverse events were also recorded. Results. Overall improvement was noted in eight out of 13 patients (61.5%, 95% CI 31.6%-86.1%). Both CAS and soft tissue swelling significantly ameliorated in eight patients at 24 wk. Five patients (38.5%) had improvement in ocular motility of ≥8 degrees. Eyelid aperture (46.2%) also decreased remarkably. For QoL, a significant improvement in appearance subscale (P = 0.008) was noted during the study, whereas no difference was observed in visual functioning subscale (P = 0.21). Two patients reported mild stomachache at 12 wk. Conclusions. SD doxycycline appears to be effective and safe for the treatment of active and moderate-to-severe GO. It might serve as a new promising therapeutic strategy for GO. This trial is registered with NCT01727973.

Immunotherapy for Graves' ophthalmopathy

PURPOSE OF REVIEW

In recent years, immunosuppressive therapy, as an alternative to corticosteroids, has been proposed as novel agents which target the various antigens involved in the pathogenesis of Graves' ophthalmopathy. Although the lack of randomized and controlled studies suggests caution in generalizing results, some data show interesting results.

RECENT FINDINGS

Potential targets for immune therapy in Graves' ophthalmopathy are the antigens expressed on the target organ of inflammation, namely the receptor and the insulin growth factor -1 receptor on fibroblasts, inflammatory cytokines, and B and T cells. The most promising results are observed with small thyroid stimulating hormone receptor molecules interacting with the receptor on thyrocytes and fibroblasts and with the anti-IGF-1 receptor antibody teprotumumab. A recent open study with tocilizumab, an anti-soluble interleukin-6 receptor, has shown inactivation of Graves' ophthalmopathy. Consistent reports on the efficacy of rituximab will have to be confirmed by randomized controlled trials, which are now in progress.

SUMMARY

Current clinical practice for Graves' ophthalmopathy will greatly benefit from the availability of immunosuppressors that act as disease-modifying drugs, as compared to steroids, the current standard treatment for Graves' ophthalmopathy. Rituximab seems to be a good candidate, as preliminary results from ongoing randomized trials suggest good efficacy with a relative well tolerated profile.

Extrathyroidal manifestations of Graves' disease: a 2014 update

INTRODUCTION

Graves' orbitopathy (GO), thyroid dermopathy (also called pretibial myxedema) and acropachy are the extrathyroidal manifestations of Graves' disease. They occur in 25, 1.5, and 0.3 % of Graves' patients, respectively. Thus, GO is the main and most common extrathyroidal manifestation. Dermopathy is usually present if the patient is also affected with GO. The very rare acropachy occurs only in patients who also have dermopathy. GO and dermopathy have an autoimmune origin and are probably triggered by autoimmunity to the TSH receptor and, likely, the IGF-1 receptor. Both GO and dermopathy may be mild to severe.

MANAGEMENT

Mild GO usually does not require any treatment except for local measures and preventive actions (especially refraining from smoking). Currently, moderate-to-severe and active GO is best treated by systemic glucocorticoids, but response to treatment is not optimal in many instances, and retreatments and use of other modalities (glucocorticoids, orbital radiotherapy, cyclosporine) and, in the end, rehabilitative surgery are often needed. Dermopathy is usually managed by local glucocorticoid treatment. No specific treatment is available for acropachy.

PERSPECTIVES

Novel treatments are presently being investigated for GO, and particular attention is paid to the use of rituximab. It is unknown whether novel treatments for GO might be useful for the other extrathyroidal manifestations. Future novel therapies shown to be beneficial for GO in randomized studies may be empirically used for dermopathy and acropachy.

Meta-analysis of methylprednisolone pulse therapy for Graves' ophthalmopathy

A meta-analysis was performed to evaluate the efficacy of methylprednisolone pulse therapy for Graves' ophthalmopathy. Eight studies involving 376 patients were included. A higher effective rate was found for patients treated with intravenous glucocorticoids (IVGC) over oral glucocorticoids (OGC) (risk ratio [RR] = 1.48; 95% confidence interval [CI] = 1.18-1.86). The combined IVGC and orbital radiotherapy (OR) was markedly more effective than OGC+OR (RR = 1.40; 95% CI = 1.11-1.77). IVGC resulted in an obvious reduction of clinical activity score (CAS) compared with OGC, with a weighted mean difference (WMD) of 0.86 (95% CI = 0.53-1.18). The WMD for the reduction of the CAS between IVGC+OR and OGC+OR was 0.66 (95% CI = 0.30-1.02). IVGC is an effective treatment and cause fewer adverse events. Limiting the total cumulative dose of methylprednisolone, careful patient selection and monitoring the condition of patients during treatment are necessary.

Regulation of IL-1 receptor antagonist by TSH in fibrocytes and orbital fibroblasts

CONTEXT

The IL-1 family plays important roles in normal physiology and mediates inflammation. The actions of IL-1 are modulated by multiple IL-1 receptor antagonists (IL-1RA), including intracellular and secreted forms. IL-1 has been implicated in autoimmunity, such as that occurring in Graves' disease (GD) and its inflammatory orbital manifestation, thyroid-associated ophthalmopathy (TAO). We have previously reported that CD34(+) fibrocytes, monocyte-lineage bone marrow-derived cells, express functional TSH receptor, the central antigen in GD. When activated by TSH, they produce IL-6, IL-8, and TNF-α. Moreover, they infiltrate the orbit in TAO in which they transition into CD34(+) fibroblasts and comprise a population of orbital fibroblasts (OFs). Little is known currently about any relationship between TSH, TSH receptor, and the IL-1 pathway.

OBJECTIVE

The objective of the study was to determine whether TSH regulates IL-1RA in fibrocytes and OFs.

DESIGN/SETTING/PARTICIPANTS

Fibrocytes and OFs were collected and analyzed from healthy individuals and those with GD in an academic clinical practice.

MAIN OUTCOME MEASURES

Real-time PCR, Western blot analysis, reporter gene assays, and cell transfections were performed.

RESULTS

TSH induces the expression of IL-1RA in fibrocytes and GD-OFs. The patterns of induction diverge quantitatively and qualitatively in the two cell types. This results from relatively small effects on gene transcription-related events but a greater influence on secreted IL-1RA and intracellular IL-1RA mRNA stabilities. These actions of TSH are dependent on the intermediate induction of IL-1α and IL-1β.

CONCLUSIONS

Our findings for the first time directly link activities of the TSH and IL-1 pathways. Furthermore, they identify novel molecular interactions that could be targeted as therapy for TAO.

Thyroid disease and the nervous system

Thyroid disorders are common in the general population and in hospitalized patients. Thyroid disease may present first with neurological complications or else may occur concurrently in patients suffering other neurological disorders, particularly those with an autoimmune etiology. For this reason neurologists will commonly encounter patients with thyroid disease. This chapter provides an overview of the neurological complications and associations of disorders of the thyroid gland. Particular emphasis is placed on conditions such as thyrotoxic periodic paralysis and myxedema coma in which the underlying thyroid disorder may be occult leading to a first, often emergency, presentation to a neurologist. Information about clinical features, diagnosis, pathogenesis, therapy, and prognosis is provided. Emphasis is placed on those aspects most likely to be relevant to the practicing neurologist and the interested reader is directed to references to good, recent review articles for further information.

Graves' orbitopathy: imperfect treatments for a rare disease

Graves' orbitopathy (GO) is the most frequent and invalidating extrathyroidal expression of Graves' disease. Its incidence and prevalence are, however, low. About three quarters of Graves' patients have no GO at diagnosis, and moderate-to-severe and severe forms represent no more that 5-6% of cases. Progression to severe forms occurs rarely, but it may be caused by risk factors, the most important being smoking and poor control of thyroid dysfunction. Lot of progress has been recently achieved in the understanding of GO pathogenesis, while the disease remains a therapeutic challenge and dilemma. Common treatments for moderate-to-severe and active forms of GO (glucocorticoids and orbital radiotherapy) frequently provide incomplete responses and may be followed by relapse or progression of GO. After the disease has been inactivated by medical treatment, many patients need rehabilitative surgery for residual manifestations (orbital decompression for exophthalmos, squint surgery for extraocular muscle dysfunction, eyelid surgery for eyelid malposition). Novel pharmacological treatments are on the horizon and might target pathogenetic mechanisms of the disease better than glucocorticoids. Clinical evidence concerning their efficacy and safety is presently lacking.

The effect of B cell depletion therapy on anti-TSH receptor antibodies and clinical outcome in glucocorticoid-refractory Graves' orbitopathy

OBJECTIVE

This case series documents the response of nine individuals with glucocorticoid-refractory Graves' orbitopathy (GO) to B cell depletion therapy with rituximab (RTX).

CONTEXT

Graves' disease (GD) is one of the commonest autoimmune conditions and is frequently associated with inflammatory changes around the eyes (GO). GO frequently results in significant functional visual impairment, and in the most severe cases, it can result in permanent loss of sight. RTX is a therapeutic monoclonal antibody, which targets cell-surface CD-20, resulting in depletion of circulating B lymphocytes. It has been found to be useful for the treatment of a number of autoimmune conditions including, in preliminary studies, GO.

DESIGN AND PATIENTS

We have treated nine individuals (1 male, 8 female, age range 37-87 years) with glucocorticoid-resistant GO with RTX since 2008. RTX was administered in divided doses at fortnightly intervals, following 500 mg IV methylprednisolone pretreatment.

MEASUREMENTS

Each patient underwent thorough assessment before and after RTX therapy, including thyroid function tests, B cell counts, thyroid autoantibody levels and detailed clinical assessment according to EUGOGO standard protocols. All patients have now been followed up for 16 months or more.

RESULTS

There was a significant reduction in thyrotropin receptor binding inhibitory immunoglobulin (TBII) levels in all patients following RTX treatment and a reduction in the clinical activity score (CAS) was seen in all cases. We also report striking improvement in pretibial thyroid dermopathy in one patient following RTX.

CONCLUSIONS

This case series adds to the growing literature demonstrating that RTX, administered in our patients with concomitant methylprednisolone, is safe and clinically effective in the treatment of active, moderate to severe and sight-threatening GO. Randomized controlled trials are now needed to confirm the efficacy of RTX for GO.

Divergent expression of IL-1 receptor antagonists in CD34⁺ fibrocytes and orbital fibroblasts in thyroid-associated ophthalmopathy: contribution of fibrocytes to orbital inflammation

CONTEXT

Thyroid-associated ophthalmopathy (TAO) manifests as inflammation of orbital connective tissue. Bone marrow-derived CD34⁺ fibrocytes infiltrate the orbit in TAO where they become CD34⁺ orbital fibroblasts. They express thyroid-specific antigens and thus may contribute to inflammation. Evidence suggests that orbital susceptibility to TAO may involve IL-1, which is modulated by IL-1 receptor antagonists, designated secreted (sIL-1RA) and intracellular (icIL-1RA).

OBJECTIVE

We sought to characterize the expression of sIL-1RA and icIL-1RA in TAO orbital fibroblasts compared to CD34⁺ fibrocytes.

DESIGN/SETTING/PARTICIPANTS

Patients with TAO and healthy donors were recruited from an academic medical center clinical practice.

MAIN OUTCOME MEASURES

Real-time PCR, cytokine-specific ELISA, gene promoter activities, transcriptional analysis, mRNA stability, and cytometric cell sorting were performed.

RESULTS

Orbital fibroblasts treated with IL-1β exhibit greater inductions of IL-1α, IL-1β, and prostaglandin endoperoxide H synthase-2 transcripts than do fibrocytes. Fibrocytes express dramatically higher basal levels of both icIL-1RA and sIL-1RA. When treated with IL-1β, icIL-1RA is induced in orbital fibroblasts but not sIL-1RA, whereas in fibrocytes, sIL-1RA is dominantly up-regulated. These inductions result from increased steady-state levels of respective mRNAs, enhanced transcript stabilities, and modestly increased gene transcription.

CONCLUSIONS

Robust responses of TAO orbital fibroblasts to IL-1β are a consequence of low-level sIL-1RA expression. This results in poorly opposed actions of IL-1β. In contrast, circulating fibrocytes express high levels of sIL-1RA, which are diminished as these cells transition to orbital fibroblasts. These findings identify an explanation for the inflammatory phenotype exhibited by TAO orbital fibroblasts and provide a potential target for altering disease susceptibility.

Prevalence and natural history of Graves' orbitopathy in the XXI century

Graves' orbitopathy (GO) is an autoimmune disorder and the main extrathyroidal expression of Graves' disease. There is a spectrum of ocular involvement in Graves' disease, from complete absence of symptoms and signs to sight-threatening conditions. The prevalence of GO varies in different published series of Graves' patients, due to confounding factors (new diagnosis vs long-lasting disease, way of defining and assessing ocular involvement, treatment of hyperthyroidism with potentially GO-modifying treatments, such as radioiodine). Recent studies, however, suggest that most Graves' patients have mild or no GO at presentation, while moderate-to-severe GO is rare, and sight-threatening GO (mostly due to dysthyroid optic neuropathy) is exceptional in non-tertiary referral centers. The natural course of GO is incompletely defined, particularly in patients with moderate- to-severe GO, because these patients require prompt and disease-modifying therapies for orbital disease. In patients with mild GO at presentation, progression to severe forms is rare, while partial or complete remission is frequent. Progression of pre-existing GO or de novo occurrence of GO is more likely in smokers. There seems to be a trend towards a decline in progression of GO, possibly due to a better control of risk factors (cigarette smoking, thyroid dysfunction, etc.) and a closer interaction between endocrinologists and ophthalmologists allowing an improved integrated management of thyroid and orbital disease.

A small molecule antagonist inhibits thyrotropin receptor antibody-induced orbital fibroblast functions involved in the pathogenesis of Graves ophthalmopathy

CONTEXT

Graves ophthalmopathy (GO) is an autoimmune disorder characterized by increased adipogenesis and hyaluronan (HA) production by orbital fibroblasts. Circulating autoantibodies (thyroid-stimulating antibodies [TSAbs]) directed at the thyrotropin receptor (TSHR) on these cells stimulate or augment these cellular processes. A recently developed drug-like small molecule inverse agonist of TSHR, NCGC00229600, termed 1, binds to TSHR and blocks basal and stimulated signal transduction.

OBJECTIVE

The purpose of this article was to determine whether 1 might inhibit HA production and relevant signaling pathways in orbital fibroblasts cultured in the presence of monoclonal TSAbs or bovine TSH (bTSH).

DESIGN

Primary cultures of undifferentiated GO orbital fibroblasts (n = 13) were untreated or treated with a TSAb (M22 or MS-1) or bTSH in serum-free medium, with or without 1 or a TSHR neutral antagonist, NCGC00242595, termed 2, which does not inhibit basal signaling but does inhibit stimulated signaling.

MAIN OUTCOME MEASURES

cAMP production, Akt phosphorylation (Ser473pAkt in media and immunoblotting for pAkt/total Akt), and HA production were analyzed.

RESULTS

Compound 1 inhibited basal cAMP, pAkt, and HA production and that stimulated by M22 in undifferentiated orbital fibroblasts. Inhibition of HA production was dose-dependent, with a half-maximal inhibitory dose of 830 nM. This compound also inhibited MS-1- and bTSH-stimulated cAMP, pAkt, and HA production. Compound 2 did not inhibit basal HA production but did inhibit M22-stimulated HA production.

CONCLUSIONS

Because cAMP, pAkt, and HA production are fibroblast functions that are activated via TSHR signaling and are important in the pathogenesis of GO, small molecule TSHR antagonists may prove to be effective in the treatment or prevention of the disease in the future.

Prevalence and natural history of Graves' orbitopathy in a large series of patients with newly diagnosed graves' hyperthyroidism seen at a single center

BACKGROUND

The prevalence and natural history of Graves' orbitopathy (GO) are poorly documented.

METHODS

A large series of 346 patients with newly diagnosed and recent onset Graves' hyperthyroidism seen at a single (nontertiary referral) center over an 8-year period were enrolled in an observational prospective study and evaluated for GO activity and severity according to the EUGOGO (European Group on Graves' Orbitopathy) criteria. After excluding patients immediately treated for moderate-to-severe GO, patients undergoing total thyroidectomy or radioactive iodine treatment, and patients lost to follow-up, 237 patients were submitted to antithyroid drug (ATD) treatment, with ocular evaluation at 6, 12, and 18 months.

RESULTS

Among the whole cohort, at presentation 255 (73.7%) had no ocular involvement, 70 (20.2%) had mild and inactive GO, 20 (5.8%) had moderate-to-severe and active GO, and 1 (0.3%) had sight-threatening GO with dysthyroid optic neuropathy. Of the 237 patients who completed the 18-month follow-up during or after ATD treatment, 194 (81.9%) had no GO at baseline. Progression to moderate-to-severe GO occurred in 5 (2.6%) of these patients. Of the 43 (18.1%) patients with mild and inactive GO at baseline, 1 (2.4%) progressed to moderate-to-severe GO, and 25 (58.1%) experienced complete remission.

CONCLUSIONS

Most patients with newly diagnosed Graves' disease have no ocular involvement. Moderate-to-severe and active GO or sight-threatening GO are rare at presentation and rarely develop during ATD treatment. Most patients (>80%) with no GO at baseline do not develop GO after an 18-month follow-up period. Remission of mild GO occurs in the majority of cases.

Efficacy and safety of three different cumulative doses of intravenous methylprednisolone for moderate to severe and active Graves' orbitopathy

BACKGROUND

Optimal doses of i.v. glucocorticoids for Graves' orbitopathy (GO) are undefined.

METHODS

We carried out a multicenter, randomized, double-blind trial to determine efficacy and safety of three doses of i.v. methylprednisolone in 159 patients with moderate to severe and active GO. Patients were randomized to receive a cumulative dose of 2.25, 4.98, or 7.47 g in 12 weekly infusions. Efficacy was evaluated objectively at 12 wk by blinded ophthalmologists and subjectively by blinded patients (using a GO specific quality of life questionnaire). Adverse events were recorded at each visit.

RESULTS

Overall ophthalmic improvement was more common using 7.47 g (52%) than 4.98 g (35%; P = 0.03) or 2.25 g (28%; P = 0.01). Compared with lower doses, the high-dose regimen led to the most improvement in objective measurement of ocular motility and in the Clinical Activity Score. The Clinical Activity Score decreased in all groups and to the least extent with 2.25 g. Quality of life improved most in the 7.47-g group, although not reaching statistical significance. No significant differences occurred in exophthalmos, palpebral aperture, soft tissue changes, and subjective diplopia score. Dysthyroid optic neuropathy developed in several patients in all groups. Because of this, differences among the three groups were no longer apparent at the exploratory 24-wk visit. Major adverse events were slightly more frequent using the highest dose but occurred also using the lowest dose. Among patients whose GO improved at 12 wk, 33% in the 7.47-group, 21% in the 4.98-group, and 40% in the 2.25-group had relapsing orbitopathy after glucocorticoid withdrawal at the exploratory 24-wk visit.

CONCLUSIONS

The 7.47-g dose provides short-term advantages over lower doses. However, this benefit is transient and associated with slightly greater toxicity. The use of a cumulative dose of 7.47 g of methylprednisolone provides short-term advantage over lower doses. This may suggest that an intermediate-dose regimen be used in most cases and the high-dose regimen be reserved to most severe cases of GO.

Association of IL12B polymorphisms with susceptibility to Graves ophthalmopathy in a Taiwan Chinese population

Background

Interleukin 12B (IL12B) gene polymorphisms have been linked to several inflammatory diseases, but their role in the development of Graves ophthalmopathy (GO) in Graves disease (GD) patients is unclear. The purpose of this study was to investigate the disease association of IL12B single nucleotide polymorphisms (SNPs).

Methods

A Taiwan Chinese population comprising 200 GD patients with GO and 271 GD patients without GO was genotyped using an allele-specific extension and ligation method. Hardy-Weinberg equilibrium was estimated using the chi-square test. Allele and genotype frequencies were compared between GD patients with and without GO using the chi-square test.

Results

The genotype and allele frequencies of examined SNPs did not differ between GD patients with and without GO. Although the genotype distribution remained nonsignificant in the sex-stratified analyses, the frequency of the T allele at SNP rs1003199 was significantly higher in patients with GO in the male cohort (P = 6.00 × 10^-3). In addition, haplotypes of IL12B may be used to predict the risk of GO (P = 1.70 × 10^-2); however, we could not prove the statistical significance of analysis after applying the Bonferroni correction.

Conclusions

Our results provide new information that the examined IL12B gene polymorphisms may be associated with susceptibility to GO in the Taiwan Chinese population in a sex-specific manner. This conclusion requires further investigation.

Imaging studies for diagnosing Graves' orbitopathy and dysthyroid optic neuropathy

Although the diagnosis of Graves' orbitopathy is primarily made clinically based on laboratory tests indicative of thyroid dysfunction and autoimmunity, imaging studies, such as computed tomography, magnetic resonance imaging, ultrasound and color Doppler imaging, play an important role both in the diagnosis and follow-up after clinical or surgical treatment of the disease. Imaging studies can be used to evaluate morphological abnormalities of the orbital structures during the diagnostic workup when a differential diagnosis versus other orbital diseases is needed. Imaging may also be useful to distinguish the inflammatory early stage from the inactive stage of the disease. Finally, imaging studies can be of great help in identifying patients prone to develop dysthyroid optic neuropathy and therefore enabling the timely diagnosis and treatment of the condition, avoiding permanent visual loss. In this paper, we review the imaging modalities that aid in the diagnosis and management of Graves' orbitopathy, with special emphasis on the diagnosis of optic nerve dysfunction in this condition.

Rehabilitative orbital decompression for Graves' orbitopathy: risk factors influencing the new onset of diplopia in primary gaze, outcome, and patients' satisfaction

BACKGROUND

Patients with moderate to severe Graves' orbitopathy (GO) rather frequently require rehabilitative surgery after medical therapy. Diplopia is the most common side effect of orbital decompression (OD). The aim of this study was to evaluate the occurrence of postoperative diplopia in primary gaze after OD, and the influence of the surgical approach on this outcome. Moreover, we investigated the results in terms of proptosis reduction, and the long-term subjective satisfaction of patients treated with OD with regard to their appearance and ocular function.

METHODS

A retrospective evaluation of 247 patients with GO treated with medial and lateral decompression (MLD) or lateral decompression (LD) OD between January 2002 and December 2009 was performed.

RESULTS

The overall prevalence of postoperative diplopia in primary gaze was 55/247 (22.3%), with a statistically significant difference (p<0.001) between patients with (36/113, 31.2%) and those without (19/134, 14.2%) preoperative diplopia in secondary gaze. The surgical procedure influenced the outcome in patients without preoperative diplopia (17.8% after MLD and 0% after LD, p=0.02), but not in patients with preoperative diplopia in secondary gaze (33.3% after MLD and 26.1% after LD, p=0.5). Overall, proptosis reduction was 5.7±2.2 mm (1-11 mm), after MLD and 4.0±1.6 mm (1-8 mm) after LD (p<0.001). Fifty-one out of 55 patients with constant, postoperative diplopia in primary gaze after OD underwent squint surgery, which was successful in all but two. Four patients refused squint surgery. Patients were also interviewed for satisfaction in terms of recovery of their appearance and ocular function after a mean of 6 years from surgery (range 2-9 years): more than 85% of patients reported a good to excellent postoperative satisfaction for both items.

CONCLUSIONS

Preoperative diplopia in secondary gaze is a risk factor for the development of diplopia in primary gaze after OD, independently of the surgical approach (MLD vs. LD). In absence of diplopia, MLD, but not LD, seems to be associated with its development in primary gaze. The reduction in proptosis after MLD is greater than that after LD. Most patients were satisfied with the results of both appearance and ocular function after OD.

A drug-like antagonist inhibits thyrotropin receptor-mediated stimulation of cAMP production in Graves' orbital fibroblasts

BACKGROUND

Fibroblasts (FIBs) within the retro-orbital space of patients with Graves' disease (GOFs) express thyrotropin receptors (TSHRs) and are thought to be an orbital target of TSHR-stimulating autoantibodies in Graves' ophthalmopathy (GO). Recently, we developed a low molecular weight, drug-like TSHR antagonist (NCGC00229600) that inhibited TSHR activation in a model cell system overexpressing TSHRs and in normal human thyrocytes expressing endogenous TSHRs. Herein, we test the hypothesis that NCGC00229600 will inhibit activation of TSHRs endogenously expressed in GOFs.

METHODS

Three strains of GOFs, previously obtained from patients with GO, were studied as undifferentiated FIBs and after differentiation into adipocytes (ADIPs), and another seven strains were studied only as FIBs. ADIP differentiation was monitored by morphology and measurement of adiponectin mRNA. FIBs and ADIPs were treated with the TSH- or TSHR-stimulating antibody M22 in the absence or presence of NCGC00229600 and TSHR activation was monitored by cAMP production.

RESULTS

FIBs contained few if any lipid vesicles and undetectable levels of adiponectin mRNA, whereas ADIPs exhibited abundant lipid vesicles and levels of adiponectin mRNA more than 250,000 times greater than FIBs; TSHR mRNA levels were 10-fold higher in ADIPs than FIBs. FIBs exhibited higher absolute levels of basal and forskolin-stimulated cAMP production than ADIPs. Consistent with previous findings, TSH stimulated cAMP production in the majority of ADIP strains and less consistently in FIBs. Most importantly, NCGC00229600 reduced both TSH- and M22-stimulated cAMP production in GOFs.

CONCLUSIONS

These data confirm previous findings that TSHR activation may cause increased cAMP production in GOFs and show that NCGC00229600 can inhibit TSHR activation in GOFs. These findings suggest that drug-like TSHR antagonists may have a role in treatment of GO.