COX-2 and SCD, markers of inflammation and adipogenesis, are related to disease activity in Graves' ophthalmopathy

New Therapeutic Horizon of Graves' Hyperthyroidism: Treatment Regimens Based on Immunology and Ingredients From Traditional Chinese Medicine

Graves’ disease is an autoimmune disease characterized by goiter and hyperthyroidism, and 25% patients develop GO. Traditional treatment options, such as antithyroid drugs, radioiodine or thyroidectomy, have remained largely unchanged over the past 70 years. For many patients, there is a high rate of recurrence after antithyroid drugs and lifelong hypothyroidism after ablation and thyroidectomy. The symptoms and quality of life of some patients have not been effectively improved. The clinical demand for new therapeutic regimens, coupled with a deeper understanding of the pathophysiology and immunobiology of Graves’ disease, has led to the emergence of several new therapeutic ideas, including biologics, small molecule peptides, immunomodulators and teprotumumab, a specific antibody targeting IGF-1R. Besides, the elements of TCM have attracted more and more interests in modern medicine, because some effective components have been successfully used in the treatment of autoimmune diseases. Based on the pathophysiology and efficacy of clinical management and treatment in Graves’ hyperthyroidism, here we review the new strategies under investigation and summarize the effective components of traditional Chinese medicine used for Graves’ hyperthyroidism, and explore their mechanisms. These therapies have opened a new window for the treatment of Graves’ disease, but the exact mechanism and the research direction still need to be further explored.

Serum CYR61 Levels are Associated with Graves' Ophthalmopathy and Smoking in Patients with Graves' Disease

Smoking is a well-known risk factor for Graves' ophthalmopathy (GO) in patients suffering from Graves' disease (GD). Cysteine-rich angiogenic inducer 61 (CYR61), which has multiple physiological functions, has been shown to be associated with GD and GO. In this study, we aimed to investigate the association between smoking and CYR61 concentrations in GD patients with and without GO. Serum CYR61 was measured by ELISA. The association between CYR61 concentration and GO was assessed with binary logistic regression in all patients and in subgroups of smokers and nonsmokers. The Spearman correlation coefficient was used to determine the correlations between CYR61 concentration and clinical parameters. CYR61 levels were significantly higher in GD patients with GO than in patients without GO, in smokers than in nonsmokers and in individuals older than 50 years than in those younger than 50 years. The subgroup of "GO smokers" had the highest CYR61 levels [median (IQR), 119 pg/ml (129.8)], compared with "GO nonsmokers" [84.2 pg/ml (90.8), p=0.04], "no GO smokers" [88.9 pg/ml (109.8), p=0.01] and "no GO nonsmokers" [79.4 pg/ml (129.89), p=0.003]. For each unit increase in CYR61 concentration, the odds of having GO in smokers significantly and independently increased by 1% (OR=1.010; 95% CI: 1.002-1.018, p=0.012). In conclusion, our results indicate that smoking and age increase serum CYR61 levels in patients with GD and GO. The role of CYR61 as a predictor of GO in patients with GD should be evaluated in prospective studies.

Adipocytes are larger in lymphedematous extremities than in controls

Lymphedema is caused by dysfunctional lymph vessels or as a complication of cancer treatment leading to edema and adipose tissue deposition. One hypothesis is that adipocyte hypertrophy contributes to the volume increase in lymphedema. The aim of the study was to compare adipocyte size in arm and leg lymphedema and controls. The adipocyte size difference was also compared between the arms and legs. Furthermore, any link between adipocyte size difference and gender, lymphedema onset, duration, previous radio- and chemotherapy was studied, as well as any relationship to total excess volume increase in the extremities, body mass index (BMI) and body weight. Adipose tissue biopsies from the lymphedematous and non-affected extremities were taken from 47 patients. The adipocytes sizes were measured using an Olympus PROVIS microscope, Olympus DP50 camera (Olympus, Tokyo, Japan) and ImageJ program (NIH, Bethesda, MD). Additional information was obtained from the Lymphedema Center database. The data were assembled in Excel and statistics was calculated in SPSS^® Statistics 23 (IBM^®, Armonk, NY). The adipocyte size (mean ± SEM) in the lymphedematous extremities was significantly larger, 8880 ± 291 μm², compared to the adipocyte size in the non-affected extremities, where it was 7143 ± 280 μm², i.e. 24% larger (p < .001). The adipocyte size increase was larger in arm than in leg lymphedema. No correlation was found between adipocyte size and gender or onset. However, a negative correlation was found between adipocyte size difference and duration. No correlation was found between adipocyte size and previous chemo- or radiotherapy. There was a positive correlation between adipocyte size and BMI. Hypertrophy of adipocytes was seen in the lymphedematous extremities versus control and contributes to the excess volume.

Mechanisms of Spica Prunellae against thyroid-associated Ophthalmopathy based on network pharmacology and molecular docking

BACKGROUND

Thyroid-associated ophthalmopathy (TAO) is an autoimmune inflammatory disorder, which lacks effective treatment currently. Spica Prunellae (SP) is popularly used for its anti-inflammatory and immune-regulating properties, indicating SP may have potential therapeutic value in TAO. Therefore, the purpose of this study is to identify the efficiency and potential mechanism of SP in treating TAO.

METHODS

A network pharmacology integrated molecular docking strategy was used to predict the underlying molecular mechanism of treating TAO. Firstly, the active compounds of SP were obtained from TCMSP database and literature research. Then we collected the putative targets of SP and TAO based on multi-sources databases to generate networks. Network topology analysis, GO and KEGG pathway enrichment analysis were performed to screen the key targets and mechanism. Furthermore, molecular docking simulation provided an assessment tool for verifying drug and target binding.

RESULTS

Our results showed that 8 targets (PTGS2, MAPK3, AKT1, TNF, MAPK1, CASP3, IL6, MMP9) were recognized as key therapeutic targets with excellent binding affinity after network analysis and molecular docking-based virtual screening. The results of enrichment analysis suggested that the underlying mechanism was mainly focused on the biological processes and pathways associated with immune inflammation, proliferation, and apoptosis. Notably, the key pathway was considered as the PI3K-AKT signaling pathway.

CONCLUSION

In summary, the present study elucidates that SP may suppress inflammation and proliferation and promote apoptosis through the PI3K-AKT pathway, which makes SP a potential treatment against TAO. And this study offers new reference points for future experimental research and provides a scientific basis for more widespread clinical application.

Therapeutic Effect of Guggulsterone in Primary Cultured Orbital Fibroblasts Obtained From Patients with Graves' Orbitopathy

Purpose

Inflammation, hyaluronan production, and adipogenesis are the main pathological events leading to Graves' orbitopathy (GO). Guggulsterone (GS), a phytosterol found in the resin of the guggul plant, is a well-known treatment for several inflammatory disorders, such as arthritis, obesity, and hyperlipidemia. Here we investigated the effects of GS treatment on GO pathology.

Methods

Using primary cultures of orbital fibroblasts from GO patients and non-GO controls, we examined the effects of GS on hyaluronan production and the production of proinflammatory cytokines induced by interleukin (IL)-1β, using real-time reverse transcription-polymerase chain reaction analysis, western blots, and enzyme-linked immunosorbent assays. Further, adipogenic differentiation was evaluated by quantification of Oil Red O staining and assessment of protein levels of peroxisome proliferator activator gamma (PPARγ), CCAAT-enhancer-binding proteins (C/EBP) α and β, and sterol regulatory element-binding protein-1 (SREBP-1).

Results

Treatment with noncytotoxic concentrations of GS resulted in the dose-dependent inhibition of IL-1β-induced inflammatory cytokines, including IL-6, IL-8, MCP-1, and COX-2, at both mRNA and protein levels. The hyaluronan level was also significantly suppressed by GS. Moreover, GS significantly decreased the formation of lipid droplets and expression of PPARγ, C/EBP α/β, and SREBP-1 in a dose-dependent manner. GS pretreatment attenuated the phosphorylation of nuclear factor-kappa B induced by IL-1β.

Conclusions

Our data show significant inhibitory effects of GS on inflammation, production of hyaluronan, and adipogenesis in orbital fibroblasts. To our knowledge, this is the first in vitro preclinical evidence of the therapeutic effect of GS in GO.

Simvastatin downregulates adipogenesis in 3T3-L1 preadipocytes and orbital fibroblasts from Graves' ophthalmopathy patients

BACKGROUND

Smoking is a strong risk factor for the development of Graves' ophthalmopathy (GO). Immediate early genes (IEGs) are overexpressed in patients with active GO compared to healthy controls. The aim of this study was to study the effects of tobacco smoking and simvastatin on preadipocytes and orbital fibroblasts (OFs) in the adipogenic process.

METHODS

Cigarette smoke extract (CSE) was generated by a validated pump system. Mouse 3T3-L1 preadipocytes or OFs were exposed to 10% CSE with or without simvastatin. Gene expression was studied in preadipocytes and OFs exposed to CSE with or without simvastatin and compared to unexposed cells or cells treated with a differentiation cocktail.

RESULTS

In 3T3-L1 preadipocytes, Cyr61, Ptgs2, Egr1 and Zfp36 expression levels were two-fold higher in cells exposed to CSE than in unexposed cells. Simvastatin downregulated the expression of these genes (1.6-fold, 5.5-fold, 3.3-fold, 1.4-fold, respectively). CSE alone could not stimulate preadipocytes to differentiate. Scd1, Ppar-γ and adipogenesis were downregulated in simvastatin-treated preadipocytes compared to nontreated preadipocytes 18-, 35- and 1.7-fold, respectively. In OFs, similar effects of CSE were seen on the expression of CYR61 (1.4-fold) and PTGS2 (3-fold). Simvastatin downregulated adipogenesis, PPAR-γ (2-fold) and SCD (27-fold) expression in OFs.

CONCLUSION

CSE upregulated early adipogenic genes in both mouse 3T3-L1 preadipocytes and human OFs but did not by itself induce adipogenesis. Simvastatin inhibited the expression of both early and late adipogenic genes and adipogenesis in preadipocytes and human OFs. The effect of simvastatin should be investigated in a clinical trial of patients with GO.

Elevated Serum Tetrac in Graves Disease: Potential Pathogenic Role in Thyroid-Associated Ophthalmopathy

CONTEXT

The sources and biological impact of 3,3',5,5' tetraiodothyroacetic acid (TA4) are uncertain. CD34+ fibrocytes express several proteins involved in the production of thyroid hormones. They infiltrate the orbit in Graves disease (GD), an autoimmune process known as thyroid-associated ophthalmopathy. It appears that the thyrotropin receptor plays an important role in the pathogenesis of thyroid-associated ophthalmopathy.

OBJECTIVE

To quantify levels of TA4 in healthy participants and those with GD, determine whether fibrocytes generate this thyroid hormone analogue, and determine whether TA4 influences the actions of thyroid-stimulating hormone and thyroid-stimulating immunoglobulins in orbital fibroblasts.

DESIGN/SETTING/PARTICIPANTS

Patients with GD and healthy donors in an academic medical center clinical practice were recruited.

MAIN OUTCOME MEASURES

Liquid chromatography-tandem mass spectrometry, autoradiography, real-time polymerase chain reaction, hyaluronan immunoassay.

RESULTS

Serum levels of TA4 are elevated in GD. TA4 levels are positively correlated with those of thyroxine and negatively correlated with serum levels of triiodothyronine. Several cell types in culture generate TA4 from ambient thyroxine, including fibrocytes, HELA cells, human Müller stem cells, and retinal pigmented epithelial cells. Propylthiouracil inhibits TA4 generation. TA4 enhances the induction by thyrotropin and thyroid-stimulating immunoglobulins of several participants in the pathogenesis of thyroid-associated ophthalmopathy, including interleukin 6, hyaluronan synthase 1, prostaglandin endoperoxide H synthase 2, and haluronan production.

CONCLUSION

TA4 may be ubiquitously generated in many tissues and enhances the biological impact of thyrotropin and thyroid-stimulating immunoglobulins in orbital connective tissue. These findings may identify a physiologically important determinant of extrathyroidal thyroid-stimulating hormone action.

Adjuvant Treatment of Graves' Disease with Diclofenac: Safety, Effects on Ophthalmopathy and Antibody Concentrations

BACKGROUND

Orbital morphological changes are often present in patients with Graves' disease (GD) already at diagnosis, and cyclooxygenase type 2 (COX-2) is overexpressed in active Graves' ophthalmopathy (GO).

OBJECTIVE

To investigate if adjuvant treatment of GD with the COX inhibitor and peroxisome proliferator-activated receptor-γ (PPAR-γ) antagonist diclofenac decreases the development of ophthalmopathy and if laboratory parameters are affected.

METHODS

This is a multicenter trial where 61 subjects were randomized to methimazole (block and replace with l-thyroxine) either with or without diclofenac 50 mg 1 × 2 for 12 months. The primary end point development of GO after 24 months was evaluated. Smoking habits were registered and the thyroid parameters TSH, free T4, free T3, TSH receptor antibodies (TRAb) and anti-TPO were followed. Safety parameters (kidney, liver and blood) and adverse events were regularly registered.

RESULTS

GO developed in 11% (n = 3) of the patients treated with diclofenac and in 21% (n = 6) of the controls (p = 0.273). The adverse event profile was acceptable without any severe events related to diclofenac. Both TRAb and anti-TPO concentrations decreased during treatment with methimazole, but the anti-TPO concentrations were lower in patients treated with diclofenac after 15 months (p = 0.031). The TRAb concentrations were not significantly changed between groups. Smokers had higher concentrations of TRAb than nonsmokers both at diagnosis of GD (p = 0.048) and after 15 months (p = 0.042).

CONCLUSIONS

Treatment with diclofenac had no significant influence on development of GO. Diclofenac reduces anti-TPO concentrations and seems to be safe to use in GD patients.

Development of a Novel Thyroid Function Fluctuated Animal Model for Thyroid-Associated Ophthalmopathy

Background

The establishment of a suitable and stable animal model is critical for research on thyroid-associated ophthalmopathy (TAO). In clinical practice, we found that patients treated with I-131 often exhibit TAO; therefore, we aimed to establish a novel thyroid function fluctuated animal model of TAO by simulating the clinical treatment process.

Methods

We treated SD rats with I-131 to damage the thyroid and then used sodium levothyroxine (L-T4) to supplement the thyroid hormone (TH) levels every seven days, leading to a fluctuating level of thyroid hormones that simulated the status of clinical TAO patients. Rats administered normal saline were considered as a control. The weight, intraocular pressure, and serum T3, T4, TSH and TRAb levels of the rats were measured, and the pathological changes were analyzed by H&E staining and transmission electron microscopy (TEM).

Results

The experimental rats (TAO group) exhibited significantly reduced weight and elevated intraocular pressure compared with the control rats. Meanwhile, the serum levels of T3 and T4 were up-regulated in the TAO group, but the TSH level decreased during the 10-week study. Moreover, increased numbers of blood vessels and inflammatory cell infiltrations were observed in the orbital tissues of the TAO rats, while no abnormal changes occurred in the control rats. The orbital myofibrils in the TAO rats appeared fractured and dissolved, with twisted structures. Mitochondrial swelling and vacuoles within the endoplasmic reticulum, swelling nerve fibers, shedding nerve myelin, and macrophages were found in the TAO group.

Conclusion

Rats treated with I-131 and sodium levothyroxine exhibited characteristics similar to those of TAO patients in the clinic, providing an effective and simple method for the establishment of a stable animal model for research on the pathogenesis and treatment of TAO.

Proteomics of Orbital Tissue in Thyroid-Associated Orbitopathy

CONTEXT

A potentially altered protein expression profile in orbital tissue from patients with thyroid-associated orbitopathy (TAO) is suspected.

OBJECTIVE

To detect for the first time changes in proteomic patterns of orbital connective tissue in TAO and compare these with control tissue using mass spectrometry.

DESIGN

Proteomics cross-sectional, comparative study.

SETTING

Two academic endocrine institutions.

SAMPLES

A total of 64 orbital and peripheral adipose tissue samples were collected from 39 patients with TAO and 25 control subjects.

METHODS

Samples were analyzed and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technology.

MAIN OUTCOME MEASURES

Mean intensity values of all identified peptides per protein.

RESULTS

Thirty-one proteins were identified, of which 16 differentiated between controls and patients with TAO. Different protein patterns between orbital and peripheral adipose tissue were observed. Compared to controls, 10 proteins were markedly up-regulated (≥ 2-fold) in the orbital tissue of untreated patients: beta IV spectrin (6.2-fold), GTP binding G protein 2 (5.6-fold), POTE ankyrin domain family member F (5.4-fold), xylulokinase (4.1-fold), kinesin family member 1A and lipocalin 1 (both 3.6-fold), semicarbazide-sensitive metalloproteinase amine oxidase 3 and polymerase I transcript release factor (both 3.4-fold), cell-cycle protein elongin A binding protein 1 (3.3-fold), annexin A2 and cavin (both 3-fold), protein pointing to cell proliferation histone H4 (2.8-fold), and ADAM metallopeptidase with thrombospondin type 1 motif 14 (2.7-fold). The highest protein up-regulations were noted in the orbital tissue of medically untreated patients. Steroid therapy markedly reduced up-regulation of these proteins, foremost in nonsmokers.

CONCLUSIONS

Proteins involved in tissue inflammation, adipose tissue differentiation, lipid metabolism, and tissue remodeling were up-regulated in orbital tissue of untreated patients with TAO. Steroids decreased the expression of these proteins, whereas smoking attenuated such effect.

TSH-receptor-expressing fibrocytes and thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is a vexing and undertreated ocular component of Graves disease in which orbital tissues undergo extensive remodelling. My colleagues and I have introduced the concept that fibrocytes expressing the haematopoietic cell antigen CD34 (CD34(+) fibrocytes), which are precursor cells of bone-marrow-derived monocyte lineage, express the TSH receptor (TSHR). These cells also produce several other proteins whose expression was traditionally thought to be restricted to the thyroid gland. TSHR-expressing fibrocytes in which the receptor is activated by its ligand generate extremely high levels of several inflammatory cytokines. Acting in concert with TSHR, the insulin-like growth factor 1 receptor (IGF-1R) expressed by orbital fibroblasts and fibrocytes seems to be necessary for TSHR-dependent cytokine production, as anti-IGF-1R blocking antibodies attenuate these proinflammatory actions of TSH. Furthermore, circulating fibrocytes are highly abundant in patients with TAO and seem to infiltrate orbital connective tissues, where they might transition to CD34(+) fibroblasts. My research group has postulated that the infiltration of fibrocytes into the orbit, their unique biosynthetic repertoire and their proinflammatory and profibrotic phenotype account for the characteristic properties exhibited by orbital connective tissues that underlie susceptibility to TAO. These insights, which have emerged in the past few years, might be of use in therapeutically targeting pathogenic orbit-infiltrating fibrocytes selectively by utilizing novel biologic agents that interfere with TSHR and IGF-1R signalling.

Smoking induces overexpression of immediate early genes in active Graves' ophthalmopathy

BACKGROUND

Cigarette smoking is a risk factor for the development of Graves' ophthalmopathy (GO). In a previous study of gene expression in intraorbital fat, adipocyte-related immediate early genes (IEGs) were overexpressed in patients with GO compared to controls. We investigated whether IEGs are upregulated by smoking, and examined other pathways that may be affected by smoking.

METHODS

Gene expression in intraorbital fat was studied in smokers (n=8) and nonsmokers (n=8) with severe active GO, as well as in subcutaneous fat in thyroid-healthy smokers (n=5) and nonsmokers (n=5) using microarray and real-time polymerase chain reaction (PCR).

RESULTS

With microarray, eight IEGs were upregulated more than 1.5-fold in smokers compared to nonsmokers with GO. Five were chosen for confirmation and were also overexpressed with real-time PCR. Interleukin-1 beta/IL-1B/(2.3-fold) and interleukin-6/IL-6/(2.4-fold) were upregulated both with microarray and with real-time PCR in smokers with GO compared to nonsmokers. Major histocompatibility complex, class II, DR beta 1/HLA-DRB1/was upregulated with microarray (2.1-fold) and with borderline significance with real-time PCR. None of these genes were upregulated in smokers compared to nonsmokers in subcutaneous fat.

CONCLUSIONS

IEGs, IL-1B, and IL-6 were overexpressed in smokers with severe active GO compared to nonsmokers, suggesting that smoking activates pathways associated with adipogenesis and inflammation. This study underlines the importance of IEGs in the pathogenesis of GO, and provides evidence for possible novel therapeutic interventions in GO. The mechanisms activated by smoking may be shared with other conditions such as rheumatoid arthritis.

Markers of inflammation and fibrosis in the orbital fat/connective tissue of patients with Graves' orbitopathy: clinical implications

Purpose. To assess FGF-β, TGF-β, and COX2 expression and immunocompetent cells in the orbital tissue of patients with severe and mild Graves' orbitopathy. Patients and Methods. Orbital tissue was taken from 27 patients with GO: (1) severe GO (n = 18), the mean clinical activity score (CAS) being 8.5 (SD 2.5); and (2) mild GO (n = 9), the mean CAS being 2.2 (SD 0.8), and from 10 individuals undergoing blepharoplasty. The expression of CD4+, CD8+, CD20+, and CD68 and FGF-β, TGF-β, and COX2 in the orbital tissue was evaluated by immunohistochemical methods. Results. We demonstrated predominant CD4+ T cells in severe GO. CD68 expression was observed in the fibrous connective area of mild GO and was robust in severe GO, while the prominent TGF-β expression was seen in all GO. Increased FGF-β expression was observed in the fibroblasts and adipocytes of severe GO. No expression of COX2 was found in patients with GO. Conclusions. Macrophages and CD4 T lymphocytes are both engaged in the active/severe and long stage of inflammation in the orbital tissue. FGF-β and TGF-β expression may contribute to tissue remodeling, fibrosis, and perpetuation of inflammation in the orbital tissue of GO especially in severe GO.

Treatment of mild to moderate Graves' ophthalmopathy with sodium diclofenac: a pilot study

OBJECTIVE

To report the use of sodium diclofenac, an antagonist of PPAR-gamma and cyclooxigenase-2 (COX-2) inhibitor in the treatment of mild to moderate Graves' ophthalmopathy.

SUBJECTS AND METHODS

Thirteen patients with clinical activity score (CAS) 2 to 7 were treated during a period ranging from 3 to 12 months (mean 7.8 ± 3.4) with oral sodium diclofenac, 50 mg every 12 hours.

RESULTS

Extra-ocular muscle restriction and CAS improved significantly, p = 0.003 and = 0.004, respectively. Ocular pain and diplopia disappeared, except for one patient who reported improvement of these symptoms. No recurrence was found after interruption of treatment.

CONCLUSIONS

Treatment of moderate Graves' ophthalmopathy with oral sodium diclofenac is a good, safe and less expensive therapeutic option. Like others new treatment trials, findings must be confirmed in a greater number of patients in a controlled study.

Intrinsic gene expression subsets of diffuse cutaneous systemic sclerosis are stable in serial skin biopsies

Skin biopsy gene expression was analyzed by DNA microarray from 13 diffuse cutaneous systemic sclerosis (dSSc) patients enrolled in an open-label study of rituximab, 9 dSSc patients not treated with rituximab, and 9 healthy controls. These data recapitulate the patient "intrinsic" gene expression subsets described previously, including fibroproliferative, inflammatory, and normal-like groups. Serial skin biopsies showed consistent and non-progressing gene expression over time, and importantly, the patients in the inflammatory subset do not move to the fibroproliferative subset, and vice versa. We were unable to detect significant differences in gene expression before and after rituximab treatment, consistent with an apparent lack of clinical response. Serial biopsies from each patient stayed within the same gene expression subset, regardless of treatment regimen or the time point at which they were taken. Collectively, these data emphasize the heterogeneous nature of SSc and demonstrate that the intrinsic subsets are an inherent, reproducible, and stable feature of the disease that is independent of disease duration. Moreover, these data have fundamental importance for the future development of personalized therapy for SSc; drugs targeting inflammation are likely to benefit those patients with an inflammatory signature, whereas drugs targeting fibrosis are likely to benefit those with a fibroproliferative signature.

Gene expression in Graves' ophthalmopathy and arm lymphedema: similarities and differences

BACKGROUND

Graves' ophthalmopathy (GO) and lymphedema share some pathogenetic mechanisms, such as edema, inflammation, and adipogenesis. The aim of this study was to examine similarities and differences between chronic GO and chronic lymphedema.

METHODS

Intraorbital adipose tissue was collected from patients with active (n = 10) or chronic GO (n = 10) and thyroid-healthy controls (n = 10). Arm subcutaneous adipose tissue was obtained from patients with chronic arm lymphedema (n = 10), where the unaffected arm served as a control. Gene expression was studied using microarray and real-time polymerase chain reaction.

RESULTS

The following genes were significantly upregulated (p < 0.05) in lymphedema but not in GO and have functions in wound healing, fibrosis, fat metabolism, inflammation, differentiation, development, adhesion, and the cytoskeleton: ATP-binding cassette, sub-family G (WHITE), member 1 (ABCG1), actin, alpha 2, smooth muscle, aorta (ACTA2), secreted frizzled-related protein 2 (SFRP2), tenascin C (TNC), pentraxin-related gene, rapidly induced by IL-1 beta (PTX3), and carboxypeptidase X (M14 family), member 1 (CPMX1). In chronic GO, but not in lymphedema, adipocyte-related immediate early genes known to be overexpressed in patients with active GO were upregulated but at a lower level than previously shown for the active phase. Genes of the Wnt pathway, such as secreted frizzled-related protein 1, 2, and 3, were up- and downregulated in both chronic GO and lymphedema. Parathyroid hormone-like hormone (PTHLH) was downregulated (p = 0.01) and apolipoprotein L domain containing 1 (APOLD1) was upregulated (p = 0.05) in both active and chronic GO.

CONCLUSIONS

There are more differences than similarities between chronic ophthalmopathy and chronic lymphedema, but both conditions exhibit less inflammation and adipogenesis compared to the active phases. In lymphedema, fibrosis dominates. PTHLH, which can inhibit adipogenesis, is downregulated both in active and chronic ophthalmopathy, indicating the possibility of an increased risk of adipogenesis.

PGE2 induces IL-6 in orbital fibroblasts through EP2 receptors and increased gene promoter activity: implications to thyroid-associated ophthalmopathy

Background

IL-6 plays an important role in the pathogenesis of Graves' disease and its orbital component, thyroid-associated ophthalmopathy (TAO). Orbital tissues become inflamed in TAO, a process in which prostanoids have been implicated. Orbital fibroblasts both generate and respond to PGE₂, underlying the inflammatory phenotype of these cells.

Methodology/Principal Findings

Using cultured orbital and dermal fibroblasts, we characterized the effects of PGE₂ on IL-6 expression. We found that the prostanoid provokes substantially greater cytokine synthesis in orbital fibroblasts, effects that are mediated through cell-surface EP₂ receptors and increased steady-state IL-6 mRNA levels. The pre-translational up-regulation of IL-6 results from increased gene promoter activity and can be reproduced with the PKA agonist, Sp-cAMP and blocked by interrupting the PKA pathway. PGE₂-induced production of cAMP in orbital fibroblasts was far greater than that in dermal fibroblasts, resulting from higher levels of adenylate cyclase. PGE₂ provokes CREB phosphorylation, increases the pCREB/CREB ratio, and initiates nuclear localization of the pCREB/CREB binding protein/p300 complex (CBP) preferentially in orbital fibroblasts. Transfection with siRNAs targeting either CREB or CBP blunts the induction of IL-6 gene expression. PGE₂ promotes the binding of pCREB to its target DNA sequence which is substantially greater in orbital fibroblasts.

Conclusion/Significance

These results identify the mechanism underlying the exaggerated induction of IL-6 in orbital fibroblasts and tie together two proinflammatory pathways involved in the pathogenesis of TAO. Moreover, they might therefore define an attractive therapeutic target for the treatment of TAO.

The Pro 12 Ala PPAR gamma gene polymorphism: possible modifier of the activity and severity of thyroid-associated orbitopathy (TAO)

OBJECTIVE

The PPAR gamma transcription factor, is involved in both adipogenesis and inflammation, which have been implicated in the pathogenesis of thyroid-associated orbitopathy (TAO). The aim of this study was to explore the possibility that the Pro(12)Ala polymorphism of the PPAR gamma gene, associated with a modified transcriptional activity, might be affecting the severity of TAO.

SUBJECTS AND DESIGN

We studied two cohorts of patients with Graves' disease (GD): Group 1 comprised 172 patients of Dutch ethnic origin with TAO, who attended the outpatients' clinic, Department of Endocrinology and Orbital Centre of the Academic Medical Centre, Amsterdam. Group 2 comprised 93 consecutive patients with GD of Greek ethnic origin, who did not have TAO. In group 1, exophthalmometry measurements, lid oedema, diplopia (n = 172) and clinical activity score (CAS) (n = 110), always assessed by the same group of three investigators, were recorded. Autoantibody levels were measured.

RESULTS

Allele frequency was 11.5%. There was no difference in the distribution of the polymorphism between GD patients with and without TAO. Among group 1 patients proptosis was significantly lower in Pro(12)Ala carriers (20.1 +/- 3.3 vs. 22.1 +/- 3.1, P = 0.003, t-test). PPAR gamma polymorphism carriers had lower TSH-Rab levels (mean rank 61.8 vs. 83.2, P = 0.015) and lower CAS (available in 110 patients) (mean rank 38.9 vs. 55.4, P = 0.022, M-W-test). The frequency of the polymorphism decreased with increasing CAS (P = 0.023 linear by linear association). Multivariate analysis (step) showed that the association of either proptosis or CAS with the PPAR gamma gene variant remained significant when age, smoking and TSH-Rab levels were taken into account (P < 0.01).

CONCLUSIONS

The distribution of the Pro(12)Ala PPAR gamma gene polymorphism is equally present in patients with GD with or without TAO. Among patients with TAO this polymorphism is associated with less-severe and less-active disease.

The eye and thyroid disease

PURPOSE OF REVIEW

The pathophysiology and optimal management of thyroid eye disease (TED) have not yet been elucidated. Recent studies have increased our knowledge of the disease process and different diagnostic and therapeutic options. This review highlights the recent progress in TED research and identifies areas requiring further advancements.

RECENT FINDINGS

The pathophysiology of TED likely involves genetic and environmental factors, which may potentiate cellular and humoral-mediated inflammation within the orbit. Despite progress in TED research, a target antigen has not been established with certainty. New diagnostic methods and questionnaires are being developed that potentially provide information regarding inflammatory activity of TED. Corticosteroids alone or in combination with orbital radiation may be effective in improving TED symptoms. New immunomodulating therapies may also have a role TED management. Surgery is highly effective for treatment of TED-induced optic nerve compression and for managing the chronic soft tissue changes of TED.

SUMMARY

A unifying hypothesis of TED pathophysiology is elusive. Further bench research into the autoimmune process is needed. In addition, large, prospective, randomized clinical trials based on the inflammatory activity of disease, while difficult to design, are essential to develop a consensus regarding the proper timing and use of anti-inflammatory medications.