Interleukin-7 expression in tears and orbital tissues of patients with Graves' ophthalmopathy

Predictive markers for anti-inflammatory treatment response in thyroid eye disease

Anti-inflammatory treatment is the primary and vital therapeutic approach for active, moderate-to-severe thyroid eye disease (TED). Accurate pretreatment prediction of treatment response is of paramount importance for the prognosis of patients. However, relying solely on the clinical activity score asa determinant of activity has led to unsatisfactory treatment outcomes. In recent years, significant advancements have been made in identifying predictive markers for anti-inflammatory treatment response in TED, clinical markers, body fluid biomarkers and imaging biomarkers. Several clinical studies have developed prediction models based on these markers. However, there is still a lack of comprehensive elucidation or comparison between the different markers. Therefore, this review aims to provide a detailed analysis of the definition, characteristics, and application of predictive markers for anti-inflammatory treatment response in TED. Through detailed literature search, 26 articles applying anti-inflammatory treatment effect prediction with a total of 1948 TED patients were used for analysis and discussion. By gaining a better understanding of the current research on predictive markers, we can accelerate and guide the exploration of treatment prediction strategies, leading us towards an era of precise therapy for TED.

Molecular Biomarkers in Thyroid Eye Disease: A Literature Review

PURPOSE

Thyroid eye disease (TED) is the most common extrathyroidal manifestation of Graves disease. Patients may be severely affected with eyelid retraction, exophthalmos, diplopia, pain, and threatened vision. Autoantibodies against thyroid-stimulating hormone receptor and insulin-like growth factor 1 receptor have shown associations with pathophysiological and clinical traits. Autoantibodies against thyroid-stimulating hormone receptor is in current clinical use as biomarker, but not with unambiguous diagnostic performance. A biomarker with high diagnostic accuracy and/or prognostic capability would be of immense value in diagnosing TED, especially in subclinical cases or when TED precedes the thyroid dysfunction. This article is a literature review on molecular biomarkers of TED.

METHODS

A literature search was performed using PubMed and Embase. Studies on molecular biomarkers in blood, tear fluid, and urine were included in the review.

RESULTS

Forty-six papers were included, of which 30, 14, and 2 studies on biomarkers in blood, tears, and urine, respectively. Fourteen of the papers evaluated the diagnostic performance of various biomarkers, 12 in blood and 2 in tears. Most studies evaluated single biomarkers, but 3 tested a panel of several markers. Except for autoantibodies against thyroid-stimulating hormone receptor, the reported diagnostic performances for the biomarkers were not confirmed in independent cohorts. In 32 studies, no or insufficient performance data were given, but the findings indicated involvement of various biologic mechanisms in TED including inflammation, oxidative stress, fibrosis, lipid metabolism, and ocular surface microflora.

CONCLUSIONS

Currently, serum autoantibodies against thyroid-stimulating hormone receptor is the only molecular biomarker with clinical utility in patients with TED. Several potential biomarkers have been investigated, and particularly panels of multiple biomarkers in tears are promising. To improve patient care, biomarkers in TED should be studied further.

Assessment of the levels of interleukin-17 and interleukin-38 in thyroid-associated ophthalmopathy patients

PURPOSE

The objective of the study was to analyse the levels of IL-17 and IL-38 in the samples of unstimulated tears, orbital adipose tissues, and sera of patients diagnosed with active forms of TAO. The correlation of the levels of IL-17 and IL-38 with clinical activity score (CAS) was scrutinized.

METHODS

A study was conducted at the Kazakhstan Scientific Research Institute of Eye Diseases (Almaty city, Kazakhstan). Study participants (n = 70) were sub-divided into 3 groups: (1) a group of patients diagnosed with active TAO (n = 25), (2) a group of patients with an inactive form of TAO (n = 28), and (3) a "control group" (patients diagnosed with orbital fat prolapse, n = 17). All patients underwent a clinical assessment and diagnostics. The activity of the disease and its severity were assessed using the CAS and NOSPECS scales. Thyroid function tests were performed, including the study of the levels of thyroid-stimulating hormone, triiodothyronine, free thyroxine, and antibodies to the thyroid-stimulating hormone receptor. IL-17 and IL-38 levels in non-stimulated tear samples, orbital tissue, and patients' sera were measured using commercial ELISA kits.

RESULTS

The results showed that the number of former smokers prevailed among patients with active TAO (48%) in comparison with patients with inactive TAO (15.4%), p = 0.001. The concentration of IL-17 significantly increased in the samples of non-stimulated tears, adipose tissues of the orbit and sera of patients with active forms of TAO. The level of IL-38 was reduced in all types of samples (p ≤ 0.05). The results of a histological study of orbital adipose tissues in the group of patients with an active form of TAO showed the presence of focal infiltration with lymphocytes, histiocytes, plasma cells, severe sclerosis and vascular plethora. We observed an association between the CAS of patients with active TAO and the level of IL-17 in sera (r = 0.885; p = 0.001). On the contrary, a negative correlation was detected for the level of IL-38 in sera.

CONCLUSIONS

The results highlighted the systemic effect of IL-17 and the local effect of IL-38 in TAO. We observed a significant increase in the production of IL-17, and a decrease in IL-38 in samples of sera and unstimulated tears (the active form of TAO). Our data indicate a correlation of IL-17 and IL-38 levels with the clinical activity of TAO.

Tears as a Source of Biomarkers in the Diagnosis of Graves' Orbitopathy

Thyroid eye disease (TED) is a poorly understood autoimmune manifestation of thyroid diseases most commonly associated with Graves' disease. Due to a lack of specific biomarkers and uncertain signs and symptoms, Graves' orbitopathy (GO) is challenging to diagnose early and treat effectively. Nowadays, there is great interest in searching for precise molecular biomarkers for early detection, disease monitoring, and clinical management. Researchers are keen to identify novel methods to predict and diagnose diseases and to monitor patient therapeutic response. Tears, due to their direct contact with the eye and the fact that lacrimal glands can also be affected by the disease, could give new insights into the mechanisms taking place in thyroid-associated orbitopathy (TAO) and reveal potential promising biomarkers. Tear fluid offers the possibility of the non-invasive acquisition of a sample with a high protein content, thereby attracting continuously growing interest in the discovery of novel biomarkers. This article provides an up-to-date overview of the various putative tear-fluid biomarkers that have been identified. In this review, we present the potential use of tears as a diagnostic fluid and tool to investigate the mechanism of ocular diseases and discuss the future research directions in this area.

A systematic review of multimodal clinical biomarkers in the management of thyroid eye disease

Thyroid Eye Disease (TED) is an autoimmune disease that affects the extraocular muscles and periorbital fat. It most commonly occurs with Graves' Disease (GD) as an extrathyroidal manifestation, hence, it is also sometimes used interchangeably with Graves' Ophthalmopathy (GO). Well-known autoimmune markers for GD include thyroid stimulating hormone (TSH) receptor antibodies (TSH-R-Ab) which contribute to hyperthyroidism and ocular signs. Currently, apart from radiological investigations, detection of TED is based on clinical signs and symptoms which is largely subjective, with no established biomarkers which could differentiate TED from merely GD. We evaluated a total of 28 studies on potential biomarkers for diagnosis of TED. Articles included were published in English, which investigated clinical markers in tear fluid, orbital adipose-connective tissues, orbital fibroblasts and extraocular muscles, serum, thyroid tissue, as well as imaging biomarkers. Results demonstrated that biomarkers with reported diagnostic power have high sensitivity and specificity for TED, including those using a combination of biomarkers to differentiate between TED and GD, as well as the use of magnetic resonance imaging (MRI). Other biomarkers which were upregulated include cytokines, proinflammatory markers, and acute phase reactants in subjects with TED, which are however, deemed less specific to TED. Further clinical investigations for these biomarkers, scrutinising their specificity and sensitivity on a larger sample of patients, may point towards selection of suitable biomarkers for aiding detection and prognosis of TED in the future.

Identification of tear-based protein and non-protein biomarkers: Its application in diagnosis of human diseases using biosensors

Discovery of robust, selective and specific biomarkers are important for early diagnosis and monitor progression of human diseases. Eye being a common target for several human diseases, vision impediment and complications are often associated with systemic and ocular diseases. Tears are bodily fluids that are closest to eye and are rich in protein content and other metabolites. As a biomarker repository, it advantages over other bodily fluids due to the ability to collect it non-invasively. In this review, we highlight some recent advancements in identification of tear-based protein biomarkers like lacryglobin and cystatin SA for cancer; interleukin-6 and immunoglobulin-A antibody for COVID-19; tau, amyloid-β-42 and lysozyme-C for Alzheimer's disease; peroxiredoxin-6 and α-synuclein for Parkinson's disease; kallikrein, angiotensin converting enzyme and lipocalin-1 for glaucoma; lactotransferrin and lipophilin-A for diabetic retinopathy and zinc-alpha-2 glycoprotein-1, prolactin and calcium binding protein-A4 for eye thyroid disease. We also discussed identification of tear based non-protein biomarkers like lysophospholipids and acetylcarnitine for glaucoma, 8-hydroxy-2'-deoxyquanosine and malondialdehyde for thyroid eye disease. We elucidate technological advancement in developing tear-based biosensors for diagnosis and monitoring diseases such as diabetes, diabetic retinopathy and Alzheimer's disease. Altogether, the study of tears as potential biomarkers for early diagnosis of human diseases is promising.

The potential of tear proteomics for diagnosis and management of orbital inflammatory disorders including Graves' ophthalmopathy

BACKGROUND

Orbital compartments harbor a variety of tissues that can be independently targeted in a plethora of disorders resulting in sight-threatening risks. Orbital inflammatory disorders (OID) including Graves' ophthalmopathy, sarcoidosis, IgG4 disease, granulomatosis with polyangiitis, and nonspecific orbital inflammation constitute an important cause of pain, diplopia and vision loss. Physical examination, laboratory tests, imaging, and even biopsy are not always adequate to classify orbital inflammation which is frequently deemed "nonspecific". Tear sampling and testing provide a potential "window" to the orbital disease process through a non-invasive technique that allows longitudinal sampling as the disease evolves. Using PubMed/Medline, we identified potentially relevant articles on tear proteomics published in the English language between 1988 and 2021. Of 303 citations obtained, 225 contained empirical data on tear proteins, including 33 publications on inflammatory conditions, 15 in glaucoma, 15 in thyroid eye disease, 1 in sarcoidosis (75) and 2 in uveitis (77,78). Review articles were used to identify an additional 56 relevant articles through citation search. In this review, we provide a short introduction to the potential use of tears as a diagnostic fluid and tool to investigate the mechanism of ocular diseases. A general review of previous tear proteomics studies is also provided, with a focus on Graves' ophthalmopathy (GO), and a discussion of unmet needs in the diagnosis and treatment of orbital inflammatory disease (OID). The review concludes by pointing out current limitations of mass spectrometric analysis of tear proteins and summarizes future needs in the field.

Bio-chemical markers of chronic, non-infectious disease in the human tear film

The tear film is a thin, moist layer covering the ocular surface and is laden with proteins, peptides, lipids, mucins, electrolytes and cellular debris which function to maintain the healthy status of the ocular surface. In many cases of ocular or systemic disease, the integrity of this layer is changed and/or the balance of its constituents is disturbed. Since tears are easy and quick to collect and can be stored for long periods, they have the potential to be a valuable source of information relevant to many disease states. The purpose of this review is to collate information on the known biomarkers of systemic disease that have been identified in tears. The range of conditions covered includes diabetes mellitus, diabetic retinopathy, diabetic peripheral neuropathy, multiple sclerosis, Parkinson's disease, Alzheimer's disease, migraine, systemic sclerosis, cystic fibrosis, thyroid disorders and cancer.

In vivo confocal microscopy assessment of meibomian glands microstructure in patients with Graves' orbitopathy

BACKGROUND

To evaluate microstructural changes in the meibomian glands (MGs) in patients with active and inactive Graves' orbitopathy (GO), using in vivo confocal microscopy (IVCM), and to investigate the correlations between clinical and confocal findings.

METHODS

Forty patients (80 eyes) with GO (34 eyes with active GO, 46 eyes with inactive GO), and 31 age- and sex-matched control participants (62 eyes) were enrolled consecutively. A researcher recorded the clinical activity score (CAS) for each patient. A complete ophthalmic examination was then performed, including external eye, ocular surface and MGs. IVCM of the MGs was performed to determine the MG acinar density (MAD), MG longest and shortest diameters (MALD and MASD), MG orifice area (MOA), MG acinar irregularity (MAI), meibum secretion reflectivity (MSR), acinar wall inhomogeneity (AWI), acinar periglandular interstices inhomogeneity (API), and severity of MG fibrosis (MF).

RESULTS

All confocal microscopy assessments of MGs significantly differed among groups (all P = 0.000). Compared to controls, GO groups showed lower MOA (1985.82 ± 1325.30 μm2 in active GO and 2021.59 ± 1367.45 μm2 in inactive GO vs. 3896.63 ± 891.90 μm2 in controls, all P = 0.000) and MAD (87.21 ± 32.69 /mm2 in active GO and 80.72 ± 35.54 /mm2 in inactive GO vs. 114.69 ± 34.90 /mm2 in controls, P = 0.001 and 0.000, respectively); greater MALD (118.11 ± 30.23 μm in active GO and 120.58 ± 27.64 μm in inactive GO vs. 58.68 ± 20.28 μm in controls, all P = 0.000) and MASD (44.77 ± 19.16 μm in active GO and 46.02 ± 20.70 μm in inactive GO vs. 27.80 ± 9.90 μm in controls, all P = 0.000); and higher degrees of MAI, MSR, and MF (all P<0.05). Eyes with active GO had higher degrees of MAI (P = 0.015), AWI (P = 0.000), and API (P = 0.000), while eyes with inactive GO had higher degrees of MSR (P = 0.000) and MF (P = 0.017). In GO groups, AWI and API were positively correlated with CAS (r = 0.640, P = 0.000; r = 0.683, P = 0.000, respectively), and MF was negatively correlated with CAS (r = - 0.228, P = 0.042).

CONCLUSIONS

IVCM effectively revealed microstructural changes of MGs in eyes with GO and provided strong in vivo evidence for the roles of obstruction and inflammation in the ocular surface disease process. Furthermore, it revealed discernible patterns of MG abnormalities in eyes with active GO and inactive GO, which are not easily distinguishable by typical clinical examinations.

Ocular surface changes in Graves' ophthalmopathy

Many patients with Graves' ophthalmopathy (GO) suffer from dry eye syndrome (DES), and this is one of the most common reasons of eye discomfort in patients with GO. The prevalence of DES in patients with GO is significantly higher than normal subjects. The ocular surface changes involving changes in tears, cornea, conjunctiva and glands occur in GO patients. However, the mechanism of how DES occurs in GO still remains unclear. In this review, the ocular surface changes were illustrated and analyzed the reasons for high prevalence of DES in GO patients.

CLEAR - Contact lens technologies of the future

Contact lenses in the future will likely have functions other than correction of refractive error. Lenses designed to control the development of myopia are already commercially available. Contact lenses as drug delivery devices and powered through advancements in nanotechnology will open up further opportunities for unique uses of contact lenses. This review examines the use, or potential use, of contact lenses aside from their role to correct refractive error. Contact lenses can be used to detect systemic and ocular surface diseases, treat and manage various ocular conditions and as devices that can correct presbyopia, control the development of myopia or be used for augmented vision. There is also discussion of new developments in contact lens packaging and storage cases. The use of contact lenses as devices to detect systemic disease has mostly focussed on detecting changes to glucose levels in tears for monitoring diabetic control. Glucose can be detected using changes in colour, fluorescence or generation of electric signals by embedded sensors such as boronic acid, concanavalin A or glucose oxidase. Contact lenses that have gained regulatory approval can measure changes in intraocular pressure to monitor glaucoma by measuring small changes in corneal shape. Challenges include integrating sensors into contact lenses and detecting the signals generated. Various techniques are used to optimise uptake and release of the drugs to the ocular surface to treat diseases such as dry eye, glaucoma, infection and allergy. Contact lenses that either mechanically or electronically change their shape are being investigated for the management of presbyopia. Contact lenses that slow the development of myopia are based upon incorporating concentric rings of plus power, peripheral optical zone(s) with add power or non-monotonic variations in power. Various forms of these lenses have shown a reduction in myopia in clinical trials and are available in various markets.

Tear-Derived Exosome Proteins Are Increased in Patients with Thyroid Eye Disease

Exosomes contain proteins, lipids, RNA, and DNA that mediate intercellular signaling. Exosomes can contribute to the pathological processes of various diseases, although their roles in ocular diseases are unclear. We aimed to isolate exosomes from tear fluids (TF) of patients with Thyroid eye disease (TED) and analyze the exosomal proteins. TFs were collected from eight patients with TED and eight control subjects. The number of TF exosomes were measured using nanoparticle-tracking analysis. The expression of specific proteins in the purified exosome pellets were analyzed using a Proteome Profiler Array Kit. Cultured normal orbital fibroblasts were incubated with TF exosomes from patients with TED and control subjects, and changes in inflammatory cytokine levels were compared. TF exosomes from TED patients showed more exosomes than the control subjects. The expression levels of exosomal proteins vitamin D-binding (VDB) protein, C-reactive protein (CRP), chitinase 3-like 1 (CHI3L1), matrix metalloproteinase-9 (MMP-9), and vascular adhesion molecule-1 (VCAM-1) were significantly increased in patients with TED, compared to those of controls. Orbital fibroblasts exposed to TF exosomes from patients with TED showed significantly higher levels of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1) production than those treated with control TF exosomes. Specific proteins showed higher expression in exosomes from TED patients, implying that they may play keys roles in TED pathogenesis.

Evaluation of IL-29 in Euthyroid Patients with Graves' Orbitopathy: A Preliminary Study

BACKGROUND

The most frequent cause of hyperthyroidism is Graves' disease (GD). Orbitopathy is the most prevalent and recognizable extrathyroidal manifestation of Graves' disease with unrevealed pathogenesis. Interleukin 29 (IL-29) is a relatively newly discovered inflammatory cytokine. Thus, the aim of this study was to evaluate the relationship between IL-29 and Graves' orbitopathy (GO) in euthyroid patients.

METHODS

Thirty-one euthyroid patients with Graves' disease and with active GO [clinical activity score (CAS) ≥ 3/7], seventeen euthyroid patients with GD but without GO, and seventy-two healthy control subjects (CS) matched for age and gender were enrolled in the study. The following parameters were evaluated in every participant: thyroid-related hormones and autoantibodies and inflammatory markers (white blood cells, hsCRP). ELISA assay was applied to measure the concentration of IL-29.

RESULTS

We found higher level of IL-29 in GO group in comparison with CS [165 (133-747) vs. 62 (62-217) pg/mL, p < 0.001]. Furthermore, participants in the subgroup with GD with GO as compared with GD without GO had higher concentration of IL-29 [165 (133-747) vs. 62 (62-558) pg/mL, p = 0.031]. The ROC analysis for IL-29 revealed IL-29 cut-off of 105 pg/mL (sensitivity 1.000 and specificity 0.597) as the best value significantly indicating the presence of GO in GD [area under the ROC curve (AUC): 0.739, 95% confidence interval (CI): 0.646-0.833, p < 0.001].

CONCLUSIONS

The present study revealed for the first time an elevated level of IL-29 in the serum of patients with GD and GO that might suggest its involvement in the pathogenesis of GD ocular complications.

Immunohistochemical analysis of human orbital tissue in Graves' orbitopathy

PURPOSE

Immunohistochemistry of orbital tissues offers a correlation between the microscopic changes and macroscopic clinical manifestation of Graves' orbitopathy (GO). Summarizing the participation of different molecules will help us to understand the pathogenesis of GO.

METHODS

The pertinent and current literature on immunohistochemistry of human orbital tissue in GO was reviewed using the NCBI PubMed database.

RESULTS

33 articles comprising over 700 orbital tissue samples were included in this review. The earliest findings included the demonstration of HLA-DR and T cell (to a lesser extent B cell) markers in GO orbital tissues. Subsequent investigators further contributed by characterizing cellular infiltration, confirming the presence of HLA-DR and TSHR, as well as revealing the participation of cytokines, growth factors, adhesion molecules and miscellaneous substances. HLA-DR and TSHR are over-expressed in orbital tissues of GO patients. The inflammatory infiltration mainly comprises CD4 + T cells and macrophages. Cytokine profile suggests the importance of Th1 (especially in early active phase) and Th17 immunity in the pathogenesis of GO. Upregulation of proinflammatory/profibrotic cytokines, adhesion molecules and growth factors finally culminate in activation of orbital fibroblasts and perpetuation of orbital inflammation. The molecular status of selected parameters correlates with the clinical presentation of GO.

CONCLUSION

Further investigation is warranted to define precisely the role of different molecules and ongoing search for new players yet to be discovered is also important. Unfolding the molecular mechanisms behind GO will hopefully provide insights into the development of novel therapeutic strategies and optimize our clinical management of the disease.

The expression of interleukin-15 and interleukin-17 in tears and orbital tissues of Graves ophthalmopathy patients

OBJECTIVE

The objective of this study was to study the levels of interleukin (IL)-15 and IL-17 in tears and orbital tissues of the patients with the Graves ophthalmopathy (GO) (active and inactive stages) and in controls.

METHODS

Twenty-four active GO patients (CAS ≥ 3/7) were collected in our research. All patients were treated with corticosteroids during the therapy process (4-15 months) and developed into the inactive phase (CAS ≤ 2/7). The tear samples were gathered from inactive and active stages of patients with GO and sex-matched and age-matched controls (volunteers, n = 24) for the enzyme-linked immunosorbent assay measurement of IL-15 and IL-17. The orbital tissues were collected from inactive stage of patients with GO and healthy volunteers for the analysis of IL-15 and IL-17 positive cells using the immunohistochemical analysis.

RESULTS

In comparison with the volunteers, significant upregulation of IL-15 and IL-17 were identified in tears of active (P < 0.05) and inactive patients with GO ( P < 0.01). Compared with inactive patients with GO, the levels of IL-15 and IL-17 in the tears were obviously higher than those in the active patients with GO. In addition, higher expression of IL-15 and IL-17 positive cells were found in the orbital organization of inactive patients with GO compared with volunteers.

CONCLUSION

The differences in IL-15 and IL-17 expression between GO patients (active and inactive stages) and controls suggested both IL-15 and IL-17 expression were significantly correlated with thyroid-associated ophthalmopathy pathogenesis and development.

Thyroid-Associated Orbitopathy and Biomarkers: Where We Are and What We Can Hope for the Future

Background

Thyroid-associated orbitopathy (TAO) is the most common autoimmune disease of the orbit. It occurs more often in patients presenting with hyperthyroidism, characteristic of Graves' disease, but may be associated with hypothyroidism or euthyroidism. The diagnosis of TAO is based on clinical orbital features, radiological criteria, and the potential association with thyroid disease. To date, there is no specific marker of the orbital disease, making the early diagnosis difficult, especially if the orbital involvement precedes the thyroid dysfunction.

Summary

The goal of this review is to present the disease and combine the available data in the literature concerning investigation of TAO biomarkers.

Conclusions

Despite the progress done in the understanding of TAO disease, some important pieces are still missing. Typically, for the future, major efforts have to be done in the discovery of new biomarkers, validation of the suspected candidates on multicenter cohorts with standardized methodologies, and establishment of their clinical performances on the specific clinical application fields in order to improve not only the management of the TAO patients but also the therapeutic options and follow-up.

The tear cytokine profile in patients with active Graves' orbitopathy

PURPOSE

The primary aim of this study is to isolate cytokines specific for active Graves' orbitopathy (GO) in the tears of affected patients. The secondary aim is to identify other cytokines of interest and to look at the profile of their levels over time.

METHODS

This is a prospective pilot study conducted at the Singapore National Eye Centre. A total of 10 patients with active GO and 10 patients from each of 3 control groups were recruited. The 3 control groups were the following: age-matched normal female patients, patients with GO who were clinically inactive and patients with bilateral viral conjunctivitis. Tears from patients from the control groups were collected on a single visit. For patients with active GO, tears were collected on presentation, at 6 months, 12 months and 18 months.

RESULTS

Of all the cytokines examined, only IL-7 yielded a difference when the concentration in patients with active GO was compared with concentrations in all the control groups. This difference was most significant at the 18-month follow-up visit.

CONCLUSIONS

Low concentrations of IL-7 in tears exhibit specificity for active GO in patients nearly 2 years from the clinical onset of activity. Although using IL-7 in tears as a biomarker for disease activity may be limited due to its late manifestation, targeting immune restitution using IL-7 may have disease modifying effects.

Tear fluid biomarkers in ocular and systemic disease: potential use for predictive, preventive and personalised medicine

In the field of predictive, preventive and personalised medicine, researchers are keen to identify novel and reliable ways to predict and diagnose disease, as well as to monitor patient response to therapeutic agents. In the last decade alone, the sensitivity of profiling technologies has undergone huge improvements in detection sensitivity, thus allowing quantification of minute samples, for example body fluids that were previously difficult to assay. As a consequence, there has been a huge increase in tear fluid investigation, predominantly in the field of ocular surface disease. As tears are a more accessible and less complex body fluid (than serum or plasma) and sampling is much less invasive, research is starting to focus on how disease processes affect the proteomic, lipidomic and metabolomic composition of the tear film. By determining compositional changes to tear profiles, crucial pathways in disease progression may be identified, allowing for more predictive and personalised therapy of the individual. This article will provide an overview of the various putative tear fluid biomarkers that have been identified to date, ranging from ocular surface disease and retinopathies to cancer and multiple sclerosis. Putative tear fluid biomarkers of ocular disorders, as well as the more recent field of systemic disease biomarkers, will be shown.

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.

Decreased serum level of IL-7 in patients with active Graves' disease

BACKGROUND

Graves' disease (GD) is a common autoimmune disease which is one of the major causes of hyperthyroidism. Interleukin 7 (IL-7) has been recently reported to play an important role in various autoimmune diseases, but its role in the pathogenesis of GD has not been assessed. The aim of this study was to evaluate the levels of IL-7 and the soluble form of its receptor (sIL-7R) in the serum of GD patients, and to identify their association with disease activity.

METHODS

A total of 37 GD patients were enrolled into the experimental group and 16 individuals into the control group. All patients were further classified into three subgroups: a GD-active group (hyperthyroidism and TRAb (thyroid stimulating hormone receptor antibody) >7.5 U/L) (N=15), a GD-inactive group (euthyreosis and TRAb<1 U/L) (N=8), and other GD patients (euthyreosis and TRAb>1 U/L) (N=14). Concentrations of IL-7 and sIL-7R were assayed with ELISA. Additionally, the relationship between IL-7 and sIL-7R serum concentrations with disease activity (free triiodothyronine [FT3], free thyroxine [FT4], thyroid stimulating hormone [TSH] and TRAb) was also analyzed.

RESULTS

The serum concentrations of IL-7 in GD-active patients were significantly lower than those of the control group as well as the GD-inactive and GD-other groups. The serum level of IL-7 in GD patients negatively correlated with FT4 and TRAb concentrations. Moreover, no significant difference was observed in the serum level of sIL-7R in GD patients compared to the control group.

CONCLUSIONS

These observations suggest that IL-7 may play a role in the pathogenesis of GD and may be associated with its clinical activity. To this end, the serum level of IL-7 could be an additional diagnostic biomarker predictive of the disease and could be particularly valuable for TRAb-negative GD patients.

Circulating microRNA predicts insensitivity to glucocorticoid therapy in Graves' ophthalmopathy

Glucocorticoid (GC) insensitivity occurs commonly in Graves' ophthalmopathy (GO), and GC therapy is associated with major adverse effects. A reliable and easily accessible biomarker is required to predict the outcome of GC therapy. This study aimed to evaluate the performance of circulating microRNA (miRNA) to predict GC insensitivity in GO patients. A total of 35 consecutive patients were included in this study. A cumulative dose of 4.5 g of methylprednisolone (MP) was administered intravenously for 12 weeks. Pretreatment serum miRNAs from the best- (N = 5) and worst- (N = 4) responding patients were profiled using miScript PCR arrays and validated by quantitative PCR in all patients. We calculated the predictive value of pretreatment assays of serum miRNAs with regard to GC insensitivity. We further investigated the roles of target miRNAs in modulating NF-κB activity and restoring transrepression of an NF-κB reporter by dexamethasone. Nine miRNAs displayed significant differences between responsive and resistant patients by miScript PCR arrays. Validation of the top two miRNAs in all 35 patients confirmed a significantly lower serum level of miR-224-5p (p = 0.0048) in resistant patients. A multivariate logistic regression model identified a composite biomarker combining baseline serum miR-224-5p and TRAb was independently associated with GC response (OR: 2.565, 95 % CI 1.011-6.505, p = 0.047). Receiver operating characteristic (ROC) curves analysis revealed the composite marker combining miR-224-5p and TRAb led to a 91.67 % positive prediction value (PPV) and a 69.56 % negative prediction value (NPV) with regard to GC resistance. Overexpression of miR-224-5p restored transrepression of the NF-κB reporter by dexamethasone under induced resistance, which may be via targeting GSK-3β to increase GR protein level. Our study demonstrated baseline serum miR-224-5p was associated with GC sensitivity in GO and in vitro overexpression of miR-224-5p restored GC sensitivity in a resistant cell model. A parameter combined serum miR-224-5p and TRAb could effectively predict GC sensitivity in GO patients.