New understanding of the role of cytokines in the pathogenesis of Graves' ophthalmopathy

RNA aptamers with specific binding affinity to CD40 (CD40Apt) represents a promising antagonist of the CD40-CD40L signaling for thyroid-associated ophthalmopathy (TAO) treatment in mouse

Thyroid-associated ophthalmopathy (TAO) is the most common autoimmune inflammatory diseases of the orbit. The CD40-CD40L pathway has been regarded as a potential molecular mechanism contributing to the development and progression of TAO, and RNA aptamers with specific binding affinity to CD40 (CD40Apt) represents a promising inhibitor of the CD40-CD40L signaling in TAO treatment. In this study, CD40Apt was confirmed to specifically recognize mouse CD40-positive ortibtal fibroblast. Mouse orbital fibroblasts were isolated from TAO mice model orbital tissues and validated. In TGF-β-induced orbital fibroblast activation model in vitro, CD40Apt administration inhibited TGF-β-induced cell viability, decreased TGF-β-induced α-SMA, Collagen I, Timp-1, and vimentin levels, and suppressed TGF-β-induced phosphorylation of Erk, p38, JNK, and NF-κB. In TAO mice model in vivo, CD40Apt caused no significant differences to the body weight of mice; furthermore, CD40Apt improved the eyelid broadening, ameliorated inflammatory infiltration and the hyperplasia in orbital muscle and adipose tissues in model mice. Concerning orbital fibroblast activation, CD40Apt reduced the levels of CD40, collagen I, TGF-β, and α-SMA in orbital muscle and adipose tissues of model mice. Finally, CD40Apt administration significantly suppressed Erk, p38, JNK, and NF-κB phosphorylation. In conclusion, CD40Apt, specifically binds to CD40 proteins in their natural state on the cell surface with high affinity, could suppress mouse orbital fibroblast activation, therefore improving TAO in mice model through the CD40 and downstream signaling pathways. CD40Apt represents a promising antagonist of the CD40-CD40L signaling for TAO treatment.

Therapeutic Effect of α-MSH in Primary Cultured Orbital Fibroblasts Obtained from Patients with Thyroid Eye Disease

Inflammation, hyaluronan production, and adipogenesis are the main pathological events leading to thyroid eye disease (TED). α-Melanocytemelanocyte-stimulating hormone (α-MSH) is a well-known tridecapeptidetreatment for several inflammatory disorders including sepsis syndrome, acute respiratory distress syndrome, rheumatoid arthritis, and encephalitis. Here, we investigated the effect of α-MSH treatment on TED. The 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Lactate Dehydrogenase (LDH) assays were performed to analyze the effect of α-MSH on cell viability and it's toxicity. Using primary cultures of orbital fibroblasts from TED patients and non-TED as control, we examined the effects of α-MSH on proinflammatory cytokine production induced by interleukin (IL)-1β, further analyzed by real-time reverse transcription-polymerase chain reaction (qPCR) and western blotting. Immunofluorescence staining assay and qPCR were performed to examine proopiomelanocortin (POMC) expression, the upstream neuropeptide of α-MSH in TED patients and non-TED control. Treatment with non-cytotoxic concentrations of α-MSH resulted in the dose-dependent inhibition of mRNA and protein levels (p < 0.05) for IL-1β-induced inflammatory cytokines: IL-6, IL-8, MCP-1, ICAM-1, and COX-2. The expression of POMC mRNA and protein were significantly higher in TED patients compared to non-TED control (p < 0.05). Our data show significant inhibitory effects of α-MSH on inflammation, POMC production in orbital fibroblasts. At present, this is the first in vitro preclinical evidence of α-MSH therapeutic effect on TED. These findings indicate that POMC and α-MSH may play a role in the immune regulation of TED and can be a potential therapeutic target.

The thyroid, the eyes and the gut: a possible connection

INTRODUCTION

Graves' disease (GD) is an autoimmune disorder responsible for 60-90% of thyrotoxicosis, with an incidence of 1 to 2 cases per 1000 population per year in England. Graves' orbitopathy (GO) is the most frequent extrathyroidal manifestation, not provoked directly by abnormal thyroid hormone levels, but by the consequence of the underlying autoimmune process. The aetiology of autoimmune disorders is due to an interplay between susceptibility genes and environmental factors, such as infections and stress. What triggers the autoimmune reaction to a specific site of the body is not yet clearly understood. The lack of knowledge in GD and GO pathogenesis implicates therapies that only limit damage but do not prevent disease onset.

MATERIAL AND METHODS

We performed on PubMed and the Cochrane Library a literature search for the articles published until July 2016 by using the search terms 'graves disease' and 'microbiome', 'orbitopathy' and 'autoimmune pathogenesis'. Reference lists of relevant studies were hand-searched for additional studies.

CONCLUSION

In this scenario, a Marie Sklodowska-Curie funded project INDIGO ( http://www.indigo-iapp.eu/ ) is investigating the role of the gut bacteria in GD and GO pathogenesis. The gut is the first and the widest area of bacteria access, with the highest concentration of T cells in the human body and trained to react to microorganisms. Interestingly, all the environmental factors involved in GD and GO pathogenesis can alter the balance within the microorganisms located in the gut, and influence the immune system, in particular the proportions of regulatory Treg and inflammatory TH17 cells. It is hoped that investigating GD and GO pathogenesis from this novel aspect will identify new targets for prevention and treatment.

Celastrol inhibits IL-1β-induced inflammation in orbital fibroblasts through the suppression of NF-κB activity

Graves' disease is an autoimmune disease of the thyroid gland, which is characterized by hyperthyroidism, diffuse goiter and Graves' ophthalmopathy (GO). Although several therapeutic strategies for the treatment of GO have been developed, the effectiveness and the safety profile of these therapies remain to be fully elucidated. Therefore, examination of novel GO therapies remains an urgent requirement. Celastrol, a triterpenoid isolated from traditional Chinese medicine, is a promising drug for the treatment of various inflammatory and autoimmune diseases. CCK‑8 and apoptosis assays were performed to investigate cytotoxicity of celastrol and effect on apoptosis on orbital fibroblasts. Reverse transcription‑polymerase chain reaction, western blotting and ELISAs were performed to examine the effect of celastrol on interleukin (IL)‑1β‑induced inflammation in orbital fibroblasts from patients with GO. The results demonstrated that celastrol significantly attenuated the expression of IL‑6, IL‑8, cyclooxygenase (COX)‑2 and intercellular adhesion molecule‑1 (ICAM‑1), and inhibited IL‑1β‑induced increases in the expression of IL‑6, IL‑8, ICAM‑1 and COX‑2. The levels of prostaglandin E2 in orbital fibroblasts induced by IL‑1β were also suppressed by celastrol. Further investigation revealed that celastrol suppressed the IL‑1β‑induced inflammatory responses in orbital fibroblasts through inhibiting the activation of nuclear factor (NF)‑κB. Taken together, these results suggested that celastrol attenuated the IL‑1β‑induced pro‑inflammatory pathway in orbital fibroblasts from patients with GO, which was associated with the suppression of NF-κB activation.

The effects of vascular endothelial growth factor (VEGF) on human orbital preadipocyte

PURPOSE

To investigate the presence of the Vascular Endothelial Growth Factor (VEGF) and its receptor (VEGFR) in human orbital preadipocytes, and to evaluate the effect of VEGF on human orbital preadipocyte differentiation and adipogenesis in vitro.

RESULTS

Four isoforms of VEGF (VEGF121, 155, 189, and 206), VEGFR-1, VEGF-2, and neuropilin-1 were expressed in human orbital preadipocytes. Treatment with 100 ng/ml VEGF induced higher expressions of C/EBPα and LPL than the non-treated control (p = 0.03 and p = 0.01) or treatment with 50ng/ml (p = 0.04 for both). At both concentrations VEGF enhanced the accumulation of intra-cytoplasmic lipid versus the control, and treatment with 100 ng/ml VEGF induced more lipid accumulation than treatment with 50 ng/ml VEGF (p = 0.03).

CONCLUSIONS

VEGF and VEGFR were observed in human orbital preadipocytes, and exogenous VEGF enhanced adipogenesis in these cells. These results suggest that VEGF plays a role as an autocrine or paracrine growth factor during human orbital preadipocyte differentiation.

Safety Profile and Effects of Pulsed Methylprednisolone on Vital Signs in Thyroid Eye Disease

Objective. To analyze changes in vital signs (heart rate (HR), systolic (SBP), and diastolic blood pressure (DBP)) during and after intravenous methylprednisolone (IVMP) and any other adverse effects. Methods. Retrospective review of charts of patients who received IVMP as treatment regime for thyroid eye disease. All subjects had vital signs charted during and after infusions. Results. This study included 38 subjects and a total of 242 infusions administered. IVMP resulted in a small but significant percentage drop in mean SBP at 30 min (p < 0.001) and 60 min (p = 0.03) but no difference at 90 min. There was also small but significant percentage drop in mean DBP and HR (DBP: p < 0.001 for 30 min, p = 0.001 for 60 min, and p = 0.02 for 90 min and HR: p < 0.001 for 30 min, 60 min, and 90 min). There were no cumulative effects on change of blood pressure or HR. There were 6 episodes of bradycardia (2.5%) and 12 episodes of moderate to severe hypertension (5%). No significant cardiovascular or hepatic toxicity was found. Conclusion. IVMP is relatively safe and efficacious. IVMP demonstrated mild and noncumulative effects on vital signs. Severe hypertension may occur in susceptible individuals such as those with underlying hypertension and uncontrolled thyroid dysfunction, whereas bradycardia may be more likely in those on beta-blockers.

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.

Graves' ophthalmopathy: a review of immunogenetics

Graves’ disease (GD) is the most common cause of thyrotoxicosis and often involves the orbits. Graves’ ophthalmopathy (GO), also known as Thyroid Eye Disease (TED), can be clinically significant and advance to sight-threatening stages. Our knowledge of the immunogenetic pathophysiology of GO is rapidly expanding. The present review is an attempt to summarize the current state of knowledge on the immunogenetics of GO. First we briefly review the epidemiology and clinical importance of GO, and then we describe in detail the macromolecular pathogenesis and finally immunogenetics of GO. Discrepancies between the results from various reports and the limitations of the available data are discussed. In particular, there is a scarcity of data from non-Asian populations. While several studies have demonstrated significant associations between polymorphisms in certain genes (especially CTLA-4, HLA-DRB-1, and TNF-α), there is a need for studies that investigate the relationship between polymorphisms and both serum and local concentrations of the resulting proteins. A complete understanding of GO susceptibility and pathogenesis has not been yet possible due to a number of important knowledge gaps that need to be filled by future research.

CD40 C/T-1 polymorphism plays different roles in Graves' disease and Hashimoto's thyroiditis: a meta-analysis

CD40 plays a pathogenic role in various autoimmune diseases. However, studies investigating the association between CD40 C/T-1 polymorphism and autoimmune thyroid diseases risk have reported conflicting results and their relative population effect remains unclear; therefore, a meta-analysis was conducted. The data for this meta-analysis included 14 (4214 cases and 3851 controls) and 4 studies (623 cases and 774 controls) for the association of the CD40 C/T-1 polymorphism with Graves' disease (GD) and Hashimoto's thyroiditis (HT), respectively. Results suggested significant association for CD40 C/T-1 polymorphism (odds ratio 1.267 per C allele, p = 0.000) with GD but without HT. The individuals who carried the C/C or C/T genotype have significantly increased GD risk compared with those who carried T/T genotype (C/C vs. T/T: OR = 1.596, 95% CI, 1.256~2.028; C/T vs. T/T: OR = 1.210, 95% CI, 1.032~1.419; dominant model: OR = 1.366, 95% CI, 1.175~1.587; recessive model: OR = 1.322, 95% CI, 1.147~1.523), while no association was observed in HT. When stratified by ethnicity, the significant association between polymorphism and GD risk of Caucasians was found only in recessive models; but that of Asians was found in all models. In the subgroup analysis of study design, we found thyroid antibody status should be ascertained in controls and euthyroidism subjects with higher levels of thyroid antibody should be excluded from control and included into HT to avoid bias. Our meta-analysis showed that CD40 C/T-1 polymorphism plays different roles in GD and HT. Further studies will be needed to confirm our findings.

In vitro study of antiadipogenic profile of latanoprost, travoprost, bimatoprost, and tafluprost in human orbital preadiopocytes

PURPOSE

To investigate the effect of prostaglandin F2α (PGF2α), latanoprost, travoprost, bimatoprost, and tafluprost on human orbital preadipocyte differentiation and intracellular lipid storage, and to reveal the potential mechanisms by which topical prostaglandin analogs induce orbital fat volume reduction and cause deep superior sulcus syndrome.

METHODS

Human orbital adipose precursors were treated in vitro for 24 h (day 1) with PGF2α, latanoprost, travoprost, bimatoprost, and tafluprost in their commercial formulations (1:100 dilution). Expressions of adipogenic transcription factor, peroxisome proliferator-activated receptor-gamma (PPARγ), and CCAAT-enhancer-binding protein α (C/EBPα) were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR) at day 7. At 14 days, cells were stained with oil red O, intracellular lipid accumulation was evaluated by lipid absorbance, and adipocyte expression marker [Lipoprotein lipase (LPL)] was determined by real-time RT-PCR.

RESULTS

Our results showed that PGF2α and topical prostaglandin analogs down-regulated the expression of PPARγ and C/EBPα, and inhibited accumulation of intra-cytoplasmic lipid droplets and expression of LPL compared with the untreated control. Comparison between the 4 drugs showed that latanoprost had the weakest antiadipogenic effect, and bimatoprost induced the most significant reduction of adipogenesis.

CONCLUSION

Latanoprost, travoprost, bimatoprost, and tafluprost inhibited human preadipocyte differentiation and intracellular lipid accumulation. Morphologic and metabolic changes in orbital adipocytes caused by PGF2α analogs are a possible pathophysiologic explanation of superior eyelid deepening in patients with glaucoma.

Thyroid eye disease: honing your skills to improve outcomes

Thyroid eye disease affects the eyelids, orbital compartment, and extraocular muscles, resulting in a highly variable degree of chemosis and enlargement of the preorbital fat pads, eyelid retraction, proptosis, restrictive strabismus, torticollis, and, rarely, compressive or congestive optic neuropathy. Although most patients with thyroid eye disease are best treated conservatively, those more severely affected may benefit from orbital decompression, strabismus surgery, or eyelid retraction repair after stabilization has occurred. Botulinum A toxin, high-dose intravenous corticosteroids, and radiation treatment are therapeutic options in select cases. Compressive or congestive optic neuropathy and severe corneal exposure warrant consideration of surgical intervention on an urgent basis without waiting for stabilization. Epidemiology and risks and benefits of high-dose steroids and radiation therapy are reviewed along with recommendations to improve conservative as well as surgical management of this disease. Strategies to manage strabismus and optimize outcomes are provided.

Prevention of relapse of Graves' disease by treatment with an intrathyroid injection of dexamethasone

INTRODUCTION

Antithyroid drugs are widely used in the treatment of Graves' disease (GD), but the relapse rate is very high after therapy withdrawal. We evaluated the reduction effects of intrathyroid injection of dexamethasone (IID) on the relapse rate of hyperthyroidism in patients with newly diagnosed GD.

PATIENTS AND METHODS

A total of 191 patients with GD completed the study. After 6 months of treatment with methimazole (MMI), the patients were randomly assigned to receive either MMI (96 patients) alone or MMI combined with IID (MMI+IID; 95 patients) treatment for 3 months, followed by continuing a dose of MMI that would maintain euthyroidism for the next 9 months in all of the patients. After withdrawal of the medical therapy, patients were followed for 24 months, and the relapse rate of hyperthyroidism was evaluated.

RESULTS

No statistical difference was observed in the levels of serum FT(4), TSH, or TSH receptor antibodies (TR-Ab), the thyroid volume, or the TR-Ab positive rate between the two groups at month 6. After the next 3 months of treatment with MMI+IID or MMI alone, the levels of TSH increased significantly, and the levels of serum TR-Ab, the TR-Ab positive rate, and thyroid volume decreased significantly in the MMI+IID group compared with the MMI group. Seven patients (7.4%) experienced a relapse of overt hyperthyroidism in the MMI+IID group and 49 patients (51%) in MMI group during the 2-yr follow-up period (P < 0.001).

CONCLUSIONS

MMI+IID treatment is helpful to prevent relapse of hyperthyroidism in GD after medical therapy withdrawal.

Preliminary evidence for interaction of PTPN12 polymorphism with TSHR genotype and association with Graves' ophthalmopathy

OBJECTIVE

Protein tyrosine phosphatases (PTPs), such as PTPN22, are important regulators of signal transduction from the T cell receptor and have been associated with autoimmunity. PTPN12 interacts with the same T cell activation accessory molecules, Grb2 and Csk kinase, as the Graves' disease (GD) associated PTPN22 encoded lymphoid tyrosine phosphatase (LYP) molecule and also plays a key role in T cell receptor signalling, leading to the hypothesis that it too may be involved in GD susceptibility.

DESIGN

PTPN12 was tested for association in a large well-characterized UK Caucasian case control cohort using seven tagging single nucleotide polymorphisms (SNPs). Patients A total of 1058 GD patients and 864 controls. Measurements Tests for association with the disease.

RESULTS

Despite adequate statistical power to detect an effect if present, none of the seven tag SNPs were associated with GD (P = 0.925-0.089). Three SNPs (rs1468682, rs4729535 and rs17467232), however, demonstrated association with the presence of ophthalmopathy NOSPECS classes 2-4 (P = 0.039-0.004). Four SNPs (rs1468682, rs4729535, rs17155601 and rs17467232) revealed evidence of interaction with the previously associated thyrotropin hormone receptor (TSHR) rs2268458 SNP (P = 0.035-0.002).

CONCLUSIONS

No association was detected between individual PTPN12 tag SNPs and GD but preliminary evidence suggests PTPN12 confers an increased risk of mild/moderate ophthalmopathy (NOSPECS classes 2-4) and that PTPN12 interacts with the TSHR. Replication of these preliminary results is now required in larger independent datasets to validate these findings.

[What is the role of allergic sensitization in Graves' disease?]

INTRODUCTION

Recent data supported the presence of T helper 2 dominance in the immune processes of Graves' disease and allergic diseases. A common role of regulatory T cells in the antigen- (or allergen-) specific immune responses was also demonstrated.

AIMS

To study whether allergic events may play a role in the initiation or progression of autoimmune Graves' disease. The occurrence of seasonal allergy may explain the fluctuation in the onset of Graves' disease.

METHODS

The presence of specific IgE levels against inhalative allergens was investigated in 327 patients with thyroid disease (Graves' disease, Hashimoto's thyroiditis, euthyroid goitre). Western blot method was used for the measurement of allergen-specific IgE levels with densitometric evaluation.

RESULTS

Allergic sensitization was found in 88 cases (58%) for Graves' disease, 51 cases (46%) for Hashimoto's thyroiditis and 31 cases (55%) for euthyroid goitre. According to allergens, significant difference was demonstrated by Penicillium notatum, Dermatophagoides farinae, alder - rye (pollens) between Graves' disease (depending ophthalmopathy) and euthyroid goitre. In the four groups based on allergen seasonality, the month of the onset in Graves' disease was associated with the season of early tree and mugwort allergy (P < 0.019 between Graves' disease and Hashimoto's thyroiditis). The number of cases, in whom the onset of Graves' disease in a given month was similar to the month of allergic season, was 17 cases vs 7 cases with Hashimoto's thyroiditis (P < 0.028).

CONCLUSIONS

The allergic sensitization was more frequent in Graves' disease, and the allergic seasonality may explain the fluctuation in the onset of Graves' disease.

Association of NFKB1 -94ins/del ATTG promoter polymorphism with susceptibility to and phenotype of Graves' disease

Recently, a functional polymorphism in the NFKB1 gene promoter (-94ins/del ATTG) has been identified and associated with chronic inflammatory diseases. The aim of this study was to analyze the association of NFKB1 polymorphism with susceptibility to and phenotype of Graves' disease (GD). The initial case-control association study, performed in a Polish-Warsaw cohort (388 GD patients and 688 controls), was followed by the two replication studies performed in Polish-Gliwice and Japanese-Kurume cohorts (198 GD patients and 194 controls, and 424 GD patients and 222 controls, respectively). The frequency of the -94del ATTG (D) allele was increased in GD compared to controls in Warsaw cohort. This finding was replicated in Gliwice cohort. Combining both Polish-Caucasian cohorts showed that the NFKB1 polymorphism was significantly associated with susceptibility to GD with a codominant mode of inheritance (P=0.00005; OR=1.37 (1.18-1.60)). No association with GD was found in Japanese cohort. However, subgroup analysis in Japanese GD patients revealed a correlation between the NFKB1genotype and the development of ophthalmopathy (P=0.009; OR=1.49 (1.10-2.01)), and the age of disease onset (P=0.009; OR=1.45 (1.09-1.91)). Our results suggest that NFKB1 -94ins/del ATTG polymorphism may be associated with susceptibility to and/or phenotype of GD.

Effects of total thyroid ablation versus near-total thyroidectomy alone on mild to moderate Graves' orbitopathy treated with intravenous glucocorticoids

CONTEXT

Graves' orbitopathy (GO) is probably caused by autoimmune reactions against autoantigen(s) shared by thyroid and orbital tissues sustained by intrathyroidal autoreactive T-lymphocytes infiltrating the orbit. Total thyroid ablation (TTA) may be beneficial for GO through removal of shared antigen(s) and autoreactive T-lymphocytes, but randomized studies are lacking.

OBJECTIVE

Our objective was to evaluate the effects of TTA in patients with GO treated with iv glucocorticoids (GC).

DESIGN/SETTING

A prospective, single-blind, randomized study was conducted at a referral center.

PATIENTS/INTERVENTIONS

Sixty patients with mild to moderate GO were randomized into: 1) near-total thyroidectomy (TX); or 2) TX plus (131)I (TTA) groups, and then treated with iv GC. Patients were evaluated 3 and 9 months after iv GC.

MAIN OUTCOME MEASURE

Overall improvement of GO at 9 months was the main outcome measure.

RESULTS

The distribution of GO outcome at 9 months was significantly more favorable in TTA than in TX patients (P = 0.0014 by chi(2) test). A cumulative significant (P = 0.0054) difference between the two groups at 3 and 9 months was found using a generalized linear model. Radioiodine uptake test and thyroglobulin assay in a patient sample showed complete ablation in the majority of TTA, but not of TX patients.

CONCLUSIONS

Compared with thyroidectomy alone, TTA is followed by a better outcome of GO in patients given iv GC. Whether TTA maintains this advantage in the long-term remains to be established.

Characterisation of 11beta-hydroxysteroid dehydrogenase 1 in human orbital adipose tissue: a comparison with subcutaneous and omental fat

Glucocorticoids (GCs) have a profound effect on adipose biology increasing tissue mass causing central obesity. The pre-receptor regulation of GCs by 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) that activates cortisol from cortisone has been postulated as a fundamental mechanism underlying the metabolic syndrome mediating adipocyte hyperplasia and hypertrophy in the omental (OM) depot. Orbital adipose tissue (OF) is the site of intense inflammation and tissue remodelling in several orbital inflammatory disease states. In this study, we describe features of the GC metabolic pathways in normal human OF depot and compare it with subcutaneous (SC) and OM depots. Using an automated histological characterisation technique, OF adipocytes were found to be significantly smaller (parameters: area, maximum diameter and perimeter) than OM and SC adipocytes (P<0 x 001). Although immunohistochemical analyses demonstrated resident CD68+ cells in all three whole tissue adipose depots, OF CD68 mRNA and protein expression exceeded that of OM and SC (mRNA, P<0 x 05; protein, P<0 x 001). In addition, there was higher expression of glucocorticoid receptor (GR)alpha mRNA in the OF whole tissue depot (P<0 x 05). Conversely, 11beta-HSD1 mRNA together with the markers of late adipocyte differentiation (FABP4 and G3PDH) were significantly lower in OF. Primary cultures of OF preadipocytes demonstrated predominant 11beta-HSD1 oxo-reductase activity with minimal dehydrogenase activity. Orbital adipocytes are smaller, less differentiated, and express low levels of 11beta-HSD1 but abundant GRalpha compared with SC and OM. OF harbours a large CD68+ population. These characteristics define an orbital microenvironment that has the potential to respond to sight-threatening orbital inflammatory disease.

New insights into antibody-mediated hyperthyroidism

The most common cause of hyperthyroidism is Graves' disease, which represents a typical example of an organ-specific autoimmune condition. The exact triggers for the disease remain unknown, but are likely to involve a complex interaction between multiple environmental factors in a genetically predisposed individual. The main feature of the condition is the presence of thyroid-stimulating antibodies, which activate the thyroid- stimulating hormone receptor, resulting in hyperthyroidism. These antibodies may also be involved in the extrathyroidal complications of the disease. The recent generation of thyroid-stimulating antibodies in animal models and the isolation of monoclonal thyroid-stimulating antibodies from a patient with Graves' disease should allow the detailed study of thyroid-stimulating antibodies-thyroid-stimulating hormone receptor interactions. This will help to shed more light on disease pathogenesis and may offer new treatment strategies in difficult cases, particularly in patients with extrathyroidal complications.

Insights into the role of fibroblasts in human autoimmune diseases

Traditional wisdom has considered fibroblasts as contributing to the structural integrity of tissues rather than playing a dynamic role in physiological or pathological processes. It is only recently that they have been recognized as comprising diverse populations of cells exhibiting complex patterns of biosynthetic activity. They represent determinants that react to stimuli and help define tissue remodelling through the expression of molecules imposing constraints on their cellular neighbourhood. Moreover, fibroblasts can initiate the earliest molecular events leading to inflammatory responses. Thus they must now be viewed as active participants in tissue reactivity. In this short review, I will provide an overview of contemporary thought about the contribution of fibroblasts to the pathogenesis of autoimmune processes through their expression of, and responses to, mediators of inflammation and tissue remodelling.

Graves' ophthalmopathy: state of the art and perspectives

Graves' ophthalmopathy (GO) is an autoimmune orbital disorder most commonly associated with Graves' disease. Recent studies have underscored the role that orbital cells, particularly fibroblasts and adipocytes, play in causing the increase in orbital content responsible for clinical manifestations of the disease. GO seems to be related to autoimmune reactions triggered by autoreactive T lymphocytes of thyroid origin, which recognize antigen(s) shared by thyroid and orbit. The nature of the antigen (or antigens) involved is not fully understood, but TSH receptor is likely to be involved. Cytokines secreted by T lymphocytes, macrophages and fibroblasts play an essential role in perpetuating the disease. Animal models of GO have been developed, but results have not clarified GO pathogenesis yet. Progress in the management of the ophthalmopathy has been very limited, and glucocorticoids, orbital radiotherapy and orbital decompression remain the mainstays in GO treatment. Novel treatments, such as somatostatin analogues, antioxidants, cytokine antagonists are currently under investigation, as well as the effects of total thyroid ablation. Cessation of smoking currently represents the only form of GO (secondary and tertiary) prevention.