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

The role of IL-6 in thyroid eye disease: an update on emerging treatments

Elevated serum interleukin-6 (IL-6) levels have been shown to correlate with disease activity in patients with thyroid eye disease (TED), a complex, heterogeneous, autoimmune disease affecting thousands of people worldwide. IL-6 plays a pivotal role in the pathogenesis of TED through three key mechanisms that together may contribute to inflammation, tissue expansion, remodeling, and fibrosis within the orbit. First, IL-6 drives an autoimmune response targeting the thyroid-stimulating hormone receptor (TSHR) by promoting the production of autoantibodies (i.e. TSHR-Ab, TSI), thereby triggering TSHR-dependent immune pathways. Second, IL-6 stimulates the activation and differentiation of orbital fibroblasts, which contributes to the inflammatory process and increase adipogenesis. Finally, IL-6 stimulates T-cell-mediated inflammation, amplifying the immune response within orbital tissues. Although corticosteroids and surgery have served as mainstays of TED treatment, a multimodal approach is often required due to the disease's heterogeneous presentation and response to current treatment options. TED is a chronic, lifelong condition characterized by periods of exacerbation and remission, with inflammation playing a central role in disease progression and severity. Because inflammation can flare intermittently throughout a patient's life, there is growing interest in targeting specific components of the immune system to reduce disease activity and severity. This review focuses on the current evidence supporting IL-6 as a key mediator of TED pathogenesis and explores its potential as a diagnostic biomarker and therapeutic target of the disease.

Genetic association of MIR-449B, GCLC, eNOS, SORD, and ENPP1 with diabetic retinopathy

Identifying the genetic risk factors of diabetic retinopathy (DR) is essential for discovering the potential pathogenesis of DR. This study determined the association of DR with five single nucleotide polymorphisms (SNPs) specifically in type 2 diabetes mellitus (T2DM) patients, including rs10061133(MIR-449B), rs17883901(GCLC), rs2070744(eNOS), rs3759890 (SORD) and rs7754561 (ENPP1). A total of 1433 individuals were enrolled in this study, comprising healthy controls (ctrls = 480), individuals with diabetes mellitus without retinopathy (DNR = 480), non-proliferative DR(NPDR = 378), and proliferative DR(PDR = 95). The five SNPs were genotyped utilizing Mass ARRAY MALDI-TOF technology. Odds ratio (OR) and 95% confidence intervals (95% CI) were calculated for the risk of genotype and allele. We performed a literature search in PubMed published before July 16, 2023. The Newcastle Ottawa Scale was used to evaluate the overall quality of the case-control studies. Consequently, we found that there were statistically significant differences between PDR cases and healthy controls for rs10061133 (P = 0.007, OR = 1.59, 95% CI = 1.32-2.23) and rs17883901 (P = 0.020, OR = 1.67, 95% CI = 1.08-2.57), rs17883901 was significantly associated with NPDR (P = 0.023, OR = 1.39, 95% CI = 1.05-1.85), there was a significant association between DR cases and healthy controls (P = 0.048, OR = 1.22, 95% CI = 1.00-1.48) for rs3759890 in the allelic model. DR show no relationships with the other two SNPs compared to healthy controls. In multivariate analyses comparing the DR and DNR groups, rs7754561(A), rs10061133(G), and rs17883901(A) were identified as risk loci for DR in individuals with a duration of diabetes of ≥5 years (P = 0.0023, P = 0.0037, and P = 0.0376, respectively). Furthermore, individuals carrying rs10061133(G) exhibited a higher risk of DR in the hyperglycemic group (glucose ≥8 mmol/L). Secondly, we showed that one polymorphism in eNOS (rs2070744, T > C) showed a suggestive association with DR in the meta-analysis (allelic model:P < 0.05, OR = 1.18, 95% CI: 1.07-1.30, Z = 3.46, I2 = 34%). Subsequently, including studies that used either healthy subjects or diabetic subjects without DR as controls, the association of eNOS rs2070744 with DR was consistently significant (P = 0.002) and exhibited intermediate heterogeneity (I2 = 48%). Furthermore, polymorphisms in GCLC (rs17883901) and SORD (rs3759890) were also associated with DR, with P-values of 0.004 (I2 = 93%) and 0.03 (I2 = 3%), respectively, suggesting their potential involvement in the disease. In conclusion, this study documented that rs10061133(G), rs17883901(A), and rs3759890(G) could be the independent risk factors for retinopathy in Chinese patients with T2DM, offering a foundation for genetic risk assessment in clinical practice. Furthermore, our meta-analysis reveals a significant association between rs2070744 and DR, implying the potential involvement of the MIR-449B, GCLC, SORD, and eNOS variants in the development of DR, which could be a promising direction for developing new treatments aimed at mitigating the risk of DR in susceptible populations.

Stretched Vascular Endothelial Cells Polarized Neutrophils to N2 Type via TRPC1-IL13-STAT3 Axis

OBJECTIVE

VECs play a crucial role in regulating the function of neutrophils, which is essential for immune responses and inflammation. As stretch-sensitive cells, VECs sense mechanical stretch through surface mechanoreceptors, converting external mechanical stimuli into biochemical signals. This study aimed to explore the molecular mechanisms underlying the regulation of neutrophil behavior by stretched VECs.

MATERIALS AND METHODS

The key cytokine-inducing neutrophil N2 polarization in the conditioned medium from stretched vascular endothelial cells (CM-stretch) was validated through multifactorial matrix and flow cytometry. Additionally, the molecular mechanism underlying the response of vascular endothelial cells to stretch was systematically verified through layer-by-layer analysis using WB.

RESULTS

IL13, not IL4, was ultimately identified as a key cytokine-inducing neutrophil N2 polarization in CM-stretch. Inhibition of the transient receptor potential channel (TRPC1) and siRNA-mediated knockdown of TRPC1 both significantly decreased IL13 production. Furthermore, neutralizing IL13 in the CM-stretch or inhibiting STAT3 phosphorylation inhibited neutrophil N2 polarization, as evidenced by reduced CD206 and VEGFA expression.

CONCLUSIONS

These results demonstrate that stretched VECs initiate a signaling cascade that induces neutrophil N2 polarization through the TRPC1-IL13-STAT3 axis, suggesting that mechanical stretching of VECs could shift neutrophil function from a pro-inflammatory to a more regulatory and healing role.

IL-17 and IL-38 gene polymorphisms in thyroid-associated ophthalmopathy

BACKGROUND

Thyroid-associated ophthalmopathy (TAO) is an autoimmune condition commonly linked with Graves' disease (GD), characterized by orbital tissue inflammation and fibrosis. It is hypothesized that gene polymorphisms may influence production of the IL-17 and IL-38 cytokines, thereby impacting TAO development and progression. This study focused on investigating the gene polymorphisms of IL-17 (rs9463772 C/T in IL17F) and IL-38 (rs3811058 C/T, rs7570267 A/G in IL1F10) in patients with GD.

METHODS

A case-control study was conducted on 132 patients with TAO and 153 patients without TAO according to eligibility criteria. After clinical examination blood samples were collected for further investigations. Genotyping was performed with the TaqMan™ Master Mix kit. Allele and genotype frequencies were compared between studied groups and subgroups.

RESULTS

No significant differences were found in age, duration of GD, or thyroid hormone between patients with and without TAO. However, a higher predisposition to develop TAO was observed among smokers (OR = 1.682, p = 0.03). Overall, no significant associations between gene polymorphisms and TAO development were identified in GD patients. Further analysis revealed that the CC genotype in IL1F10 rs3811058 polymorphism among Caucasians was associated with an increased risk of TAO (OR = 2.7, p = 0.02), as well as allele differences were also significant (OR = 2.8, p = 0.001).

CONCLUSIONS

These findings shed light on TAO genetic predispositions in Kazakhstani GD patients, notably among Caucasians, underscoring the need for further research. These results may offer valuable targets for the development of novel treatments for TAO.

The Role of FOXP3 Polymorphisms in Graves' Disease with or without Ophthalmopathy in a Turkish Population

Objectives

Forkhead box P3 (FOXP3) gene polymorphisms have been evaluated in many autoimmune diseases, including Graves' disease (GD), in different populations. However, those polymorphisms have not been analyzed in GD or Graves' ophthalmopathy (GO) in the Turkish population. In this study, we aimed to evaluate the frequency of FOXP3 polymorphisms in GD with or without ophthalmopathy in a Turkish population.

Materials and Methods

The study included 100 patients with GO, 74 patients with GD without ophthalmopathy, and 100 age- and sex-matched healthy controls. In all study participants, rs3761547 (-3499 A/G), rs3761548 (-3279 C/A), and rs3761549 (-2383 C/T) single nucleotide polymorphisms (SNPs) were detected using the polymerase chain reaction-restriction fragment length polymorphism method. The chi-square test was used to evaluate genotype and allele frequencies. Odds ratios and 95% confidence intervals were calculated for genotype and allele risks.

Results

In the patient group (including GD with or without ophthalmopathy), the rs3761548 AC and AA genotype and rs3761549 CT genotype were significantly more frequent than in the control group (all p<0.05). No genotypic and allelic differences were observed for rs3761547 between the patient and control groups (all p>0.05). There was no statistically significant difference between the GO and GD without ophthalmopathy groups concerning the allele and genotype frequencies of all three FOXP3 SNPs (all p>0.05).

Conclusion

The AC and AA genotypes of rs3761548 (-3279) and CT genotype of rs3761549 (-2383 C/T) were shown to be possible risk factors for GD development in the Turkish population. However, none of the three SNPs was shown to be associated with the development of GO in patients with GD.

Lack of Association between LOXL1 Variants and Pigment Dispersion Syndrome/Pigmentary Glaucoma: A Meta-Analysis

The phenotypic similarities between exfoliation syndrome (XFS)/exfoliation glaucoma (XFG) and pigment dispersion syndrome (PDS)/pigmentary glaucoma (PG), particularly their association with material deposition in the eye's anterior segment, have prompted investigations into genetic commonalities. This study focuses on the LOXL1 gene, conducting a comprehensive meta-analysis of three candidate gene association studies. We analyzed three single nucleotide polymorphisms (SNPs) of LOXL1: rs1048661, rs3825942, and rs2165241. Our results reveal nominal significance for the exonic SNPs rs1048661 and rs3825942 (p ≤ 0.01), but show no significant association for the intronic SNP rs2165241 (p = 0.83) with PDS/PG. There was homogeneity across study cohorts (I2 = 0), and sensitivity analyses and funnel plots confirmed a lower likelihood of bias in our findings. The lack of a statistically significant association between LOXL1 variants and PDS/PG at p < 0.05 was attributable to the insufficient statistical power of the pooled data, which ranged from 5% to 37% for the three SNPs. This study suggests no association between LOXL1 variants and PDS/PG. Further validation and exploration of XFS/XFG-associated genes in larger and more diverse cohorts would be helpful to determine the genetic correlation or distinctiveness between these conditions.

Genome-Wide Associations and Confirmatory Meta-Analyses in Diabetic Retinopathy

The present study aimed to summarize and validate the genomic association signals for diabetic retinopathy (DR), proliferative DR, and diabetic macular edema/diabetic maculopathy. A systematic search of the genome-wide association study (GWAS) catalog and PubMed/MELINE databases was conducted to curate a comprehensive list of significant GWAS discoveries. The top signals were then subjected to meta-analysis using established protocols. The results indicate the need for improved consensus among DR GWASs, highlighting the importance of validation efforts. A subsequent meta-analysis confirmed the association of two SNPs, rs4462262 (ZWINT-MRPS35P3) (odds ratio = 1.38, p = 0.001) and rs7903146 (TCF7L2) (odd ratio = 1.30, p < 0.001), with DR in independent populations, strengthening the evidence of their true association. We also compiled a list of candidate SNPs for further validation. This study highlights the importance of consistent validation and replication efforts in the field of DR genetics. The two identified gene loci warrant further functional investigation to understand their role in DR pathogenesis.

Cytokines in Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO), also known as thyroid eye disease (TED) or Graves' orbitopathy (GO), is a complex autoimmune condition causing visual impairment, disfigurement, and harm to patients' physical and mental health. The pathogenesis of TAO has not been fully elucidated, and the mainstream view is that coantigens shared by the thyroid and orbit trigger remodeling of extraocular muscles and orbital connective tissues through an inflammatory response. In recent years, cytokines and the immune responses they mediate have been crucial in disease progression, and currently, common evidence has shown that drugs targeting cytokines, such as tocilizumab, infliximab, and adalimumab, may be novel targets for therapy. In this review, we summarize the research development of different cytokines in TAO pathogenesis in the hope of discovering new therapeutic targets.

Association of IL-1β, NLRP3, and COX-2 Gene Polymorphisms with Autoimmune Thyroid Disease Risk and Clinical Features in the Iranian Population

Background

Grave's disease (GD) and Hashimoto's thyroiditis (HT) are autoimmune diseases of the thyroid gland in which genetic predisposition plays a major role in their development. Currently, the role of NLRP3 inflammasome and COX-2 has been documented in many autoimmune diseases. The purpose of the study is to delineate the impact of IL-1β (rs1143634), NLRP3 (rs3806265), and COX-2 (rs2745557) gene polymorphisms in the development of GD and HT.

Methods

A total of 256 newly diagnosed patients with autoimmune thyroid disease (135 patients with HT and 121 GD patients) as case groups and 145 controls were included in the study.

Results

Recessive and overdominant models showed a significant association between IL-1β rs1143634 SNP and HT development risk. The frequency of TT genotype and T allele of IL-1β rs1143634 SNP in the control group was significantly higher than the GD group. There was no significant association between NLRP3 rs3806265 polymorphism and HT and GD development. The frequency of GA genotype of COX-2 (rs2745557) in the control group was significantly higher than that in the HT group. There was no significant association between COX-2 rs2745557 genotypic and allelic distribution and GD development risk. The results revealed a significant relationship between some clinical features of HT and GD groups and SNPs studied.

Conclusion

The results manifest the significant impact of IL-1β rs1143634 and COX-2 (rs2745557) SNPs and HT development and IL-1β rs1143634 SNP on GD occurrence risk. Furthermore, a significant relationship was observed between some clinical features of HT and GD groups and studied SNPs.

The risk factors for Graves' ophthalmopathy

PURPOSE

This review aimed to provide an overview of current research into the risk factors for Graves' ophthalmopathy (GO).

METHODS

To find information about the risk factors for GO, the research database PubMed was searched and relevant articles were obtained to extract information about risk factors.

RESULTS

Smoking has been widely accepted as an important risk factor and cigarette smoking cessation has been shown to improve the outcome and decrease the onset of GO. Radioactive iodine on the thyroid may induce hyperthyroidism and increase the occurrence of GO. Selenium deficiency is a risk factor for GO and the supplementation of selenium has been an adjuvant therapy. Decreasing stressful life events (SLE) may help improve GO. Imbalance in intestinal flora is essential to GO, with Yersinia enterocolitica and Escherichia coli both increased in the digestive tract of the individual with GO. In addition, controlling serum cholesterol may help improve GO since adipogenesis is an important pathological change in its pathogenesis. Considering the correlation between Graves' disease and GO, maintaining normal thyroid function hormone level is the first-line therapeutic strategy to prevent progression of GO. An increase in antibodies such as TSHR and IGF-1R is the main predictor of GO. Besides, gender and gene polymorphism are also risk factors towards GO.

CONCLUSIONS

Risk factors for GO arise from five sources: physical and chemical environment, social-psychological environment, biological environment, the human organism, and genetic codes. Risk factors within these categories may interact with each other and their mechanisms in promoting the development of GO are complex. Research into risk factors for GO may promote emerging fields related to GO such as control of autoantibodies and intestinal microbiota.

A data-driven approach for the discovery of biomarkers associated with thyroid eye disease

Background

Thyroid eye disease (TED) is the most common autoimmune disease and usually occurs in patients with hyperthyroidism. In this disease, eye-related tissue, such as eye muscles, eyelids, tear glands, etc., become inflated, which causes the eyes and eyelids to become red, swollen, and uncomfortable. The pathophysiology of this disease is still poorly known.

Aim

This study aims to discover potential biomarkers and regulatory pathways of TED which will not only help to diagnose the disease and understand orbital involvement in thyroid dysfunction but also provide an insight for better therapeutics.

Methods

We applied a data-driven approach by combining gene biomarkers both from published literature and computationally predicted from microarray gene expression data. Further, the DAVID tool is used for Gene Ontology-based enrichment analysis.

Results

We obtained a total of 22 gene biomarkers, including 18 semi-automatically curated from the literature and 4 predicted using data-driven approaches, involved in the pathogenesis of TED that can be used as potential information for therapeutic targets. Further, we constructed a regulatory pathway of TED biomarkers comprises of 310 connected components, and 1134 interactions using four prominent interaction databases.

Conclusion

This constructed pathway can be further utilized for disease dynamics and simulation studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01903-9.

Association of UCP1 and UCP2 variants with diabetic retinopathy susceptibility in type-2 diabetes mellitus patients: a meta-analysis

BACKGROUND

Genetic association of uncoupling proteins (UCPs) variants with the susceptibility of diabetic retinopathy (DR) in diabetes mellitus (DM) patients has been reported but with controversy. Here we aimed to conduct a meta-analysis to confirm the association of different UCPs variants with DR.

METHODS

Three databases (Medline Ovid, Embase Ovid and CENTRAL) were applied in the literature search. Five genetic models, including allelic, homozygous, heterozygous, dominant and recessive models, were evaluated. Odds ratios (OR) were estimated under the random or fixed-effects models. Subgroup analyses, publication bias and sensitivity analyses were also conducted.

RESULTS

Eleven studies on 2 UCPs variants (UCP1 rs1800592 and UCP2 rs659366) were included. Our meta-analysis showed that UCP1 rs1800592 was not associated with DR in type-2 DM patients, and UCP2 rs659366 also showed no association with DR. In the subgroup analyses on the stage of DR, allele G of UCP1 rs1800592 significantly increased the susceptibility of proliferative diabetic retinopathy (PDR) in type-2 DM patients in the allelic (OR = 1.26, P = 0.03) and homozygous models (OR = 1.60, P = 0.04). Subgroup analysis on ethnicity did not found any significant association of rs1800592 and rs659366 with DR.

CONCLUSION

Our meta-analysis confirmed the association of UCP1 rs1800592 variant with PDR in patients with type-2 DM, suggesting its potential as a genetic marker for PDR prediction in population screening.

Association of variant on the promoter of cluster of differentiation 74 in graves disease and graves ophthalmopathy

The macrophage migration inhibitory factor (MIF)/cluster of differentiation 74 (CD74) plays a role in immunological functions. The present study aims to investigate whether single-nucleotide polymorphisms (SNPs) in the MIF and CD74 are risk factors for developing Graves ophthalmopathy (GO) in patients with Graves disease (GD). A case–control study enrolled 484 patients with GD (203 with and 281 without GO) and 1000 healthy individuals. SNPs were discriminated using real-time polymerase chain reaction. Hardy–Weinberg equilibrium, as well as frequencies of allele and genotype between GD patients with and without GO, were estimated using the Chi-square test. The effects of CD74 on adipocyte proliferation and differentiation were evaluated using 3T3-L1 preadipocytes. Quantitative DNA-immunoprecipitation was used to detect the binding capacity of NR3C1 and FOXP3 to A/G oligonucleotides. The results showed that individuals carrying the GG genotype at rs2569103 in the CD74 had a decreased risk of developing GD (P=3.390 × 10⁻¹¹, odds ratio (OR) = 0.021, 95% confidence interval (CI) = 0.003–0.154); however, patients with GD carrying the AG genotype at rs2569103 in the CD74 had an increased risk of developing GO (P=0.009, OR = 1.707, 95% CI = 1.168–2.495). The knockdown of CD74 reduced adipocyte proliferation and differentiation. NR3C1 had a higher affinity for A, whereas FOXP3 had a higher affinity for G of rs2569103. The results suggested the existence of a link between the genetic variation of CD74 promoter and the risk for developing GD and GO, which should be considered in clinical practice.

Susceptible loci associated with autoimmune disease as potential biomarkers for checkpoint inhibitor-induced immune-related adverse events

Unprecedented successes regarding cancer immunotherapy have been achieved, in which therapeutic agents are used to target immune cells rather than cancer cells. The most effective immunotherapy to date is the group of immune checkpoint inhibitors (CPI), targeting, for example, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) or programmed cell death protein (PD-1). TThe combination of these therapies (anti-PD-1 with anti-CTLA-4) induces high response rates, and seem to be increased further when applied in early-stage disease. However, combined CTLA-4 plus PD-1 blockade causes frequent high-grade immune-related adverse events (irAE). To date, research on biological mechanism of irAEs is scarce and no widely accepted biomarkers predicting onset of severe irAEs have been identified. The similarity of irAEs to autoimmune disorders fuels the hypothesis that irAEs may be linked to susceptible genetic loci related to various autoimmune diseases. In this review, we extensively searched for susceptible loci associated with various autoimmune diseases, and pooled them in groups most likely to be associated with CPI-induced irAEs. These sets could be used in future research on predicting irAEs and guide physicians in a more refined and personal manner.

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

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

Poly (ADP-ribose) polymerase-1 (PARP-1) in Chinese patients with Graves’ disease and Graves’ ophthalmopathy

We aimed to evaluate the genetic variation of poly (ADP-ribose) polymerase-1 (PARP-1) as risk factor in development of Graves’ disease (GD) and Graves’ ophthalmopathy (GO) among Chinese individuals. Patients with confirmed diagnosis of GD or healthy individuals with no clinical symptoms of hyperthyroiditis were enrolled at the Department of Ophthalmology, Tianjin First Center Hospital, China. Genetic polymorphism was studied in plasma DNA samples of subjects by polymerase chain reaction of restriction fragment length polymorphism to confirm our hypothesis. Cytokine levels were measured routinely on serum samples of subjects by sandwich ELISA technique. Patients with GG genotype (odds ratio (OR) 95% CI = 2.25 (1.35–3.73), p = 0.002) and carriers of G allele (OR = 2.03 (1.23–3.36), p = 0.006) were at high risk of developing ophthalmopathy. Polymorphism of del/ins of nuclear factor-κB1 gene (NFkB1) gene (OR = 7.1 (2.88–17.52), p < 0.0001) and PARP-1 C410T polymorphism was found to be associated with GO (p < 0.05). Cytokine level was significantly higher in patients with GD (p < 0.05), but no significant change in cytokines level among GO patients from baseline (p > 0.05). Our study results recommended that polymorphism of PARP-1 gene is more likely responsible for development of GD in Chinese individuals. We also observed that the polymorphism of gene-related del/ins to NFkB1 in development of GO.

A meta-analysis of associations of LEPR Q223R and K109R polymorphisms with Type 2 diabetes risk

Background

Leptin receptor (LEPR) plays a pivotal role in the control of body weight, energy metabolism, and insulin sensitivity. Various genetic association studies were performed to evaluate associations of LEPR genetic variants with type 2 diabetes (T2D) susceptibility.

Methods

A comprehensive search was conducted to identify all eligible case-control studies for examining the associations of LEPR single nucleotide polymorphisms (SNPs) Q223R (rs1137101) and K109R (rs1137100) with T2D risk. Odds ratios (OR) and corresponding 95% confidence intervals (CIs) were used to measure the magnitudes of association.

Results

For Q223R, 13 studies (11 articles) consisting of a total of 4030 cases and 2844 controls, and for K109R 7 studies (7 articles) consisting of 3319 cases and 2465 controls were available. Under an allele model, Q223R was not significantly associated with T2D risk (OR = 1.09, 95% CI: 0.80–1.48, P-value = 0.5989), which was consistent with results obtained under four genotypic models (ranges: ORs 1.08–1.20, 95% CIs: 0.58–2.02 to 0.64–2.26; P-values, 0.3650–0.8177, which all exceeded multiplicity-adjusted α = 0.05/5 = 0.01). In addition, no significant association was found between K109R and T2D risk based on either an allele model (OR = 0.93, 95% CI: 0.85–1.03, P-value = 0.1868) or four genotypic models (ranges: ORs 0.81–0.99, 95% CIs: 0.67–0.86 to 0.97–1.26, P-values, 0.0207–0.8804 which all exceeded multiplicity-adjusted α of 0.01). The magnitudes of association for these two SNPs were not dramatically changed in subgroup analyses by ethnicity or sensitivity analyses. Funnel plot inspections as well as Begg and Mazumdar adjusted rank correlation test and Egger linear regression test did not reveal significant publication biases in main and subgroup analyses. Bioinformatics analysis predicted that both missense SNPs were functionally neutral and benign.

Conclusions

The present meta-analysis did not detect significant genetic associations between LEPR Q223R and K109R polymorphisms and T2D risk.

The Emerging Role of Epigenetics in Autoimmune Thyroid Diseases

Autoimmune thyroid diseases (AITD) are a group of both B cell- and T cell-mediated organ-specific autoimmune diseases. Graves’ disease and Hashimoto thyroiditis are the two main clinical presentations of AITD. Both genetic and environmental factors have important roles in the development of AITD. Epigenetics have been considered to exert key roles in integrating those genetic and environmental factors, and epigenetic modifications caused by environmental factors may drive genetically susceptibility individuals to develop AITD. Recent studies on the epigenetics of AITD have provided some novel insights into the pathogenesis of AITD. The aim of this review is to provide an overview of recent advances in the epigenetic mechanisms of AITD, such as DNA methylation, histone modifications, and non-coding RNAs. This review highlights the key roles of epigenetics in the pathogenesis of AITD and potential clinical utility. However, the epigenetic roles in AITD are still not fully elucidated, and more researches are needed to provide further deeper insights into the roles of epigenetics in AITD and to uncover new therapeutic targets. Although there are many studies assessing the epigenetic modifications in AITD patients, the clinical utility of epigenetics in AITD remains poorly defined. More studies are needed to identify the underlying epigenetic modifications that can contribute to accurate diagnosis of AITD, adequate choice of treatment approach, and precise prediction of treatment outcomes.

Genetic associations of the thyroid stimulating hormone receptor gene with Graves diseases and Graves ophthalmopathy: A meta-analysis

Graves' disease (GD) is a common thyroid disease, and Graves ophthalmopathy(GO) is the most common extra-thyroidal manifestation of GD. Genetic associations of the thyroid stimulating hormone receptor (TSHR) gene with GD and GO have been studied in different population groups for a long time. We aimed to obtain a more precise estimation of the effects of TSHR single nucleotide polymorphisms (SNPs) on GD/GO using a meta-analysis. Publications were searched on Pub Med and EMBASE up to December 30, 2015. Eight studies involving three SNPs (rs179247, rs12101255, and rs2268458), which included 4790 cases and 5350 controls, met the selection criteria. The pooled odds ratios (OR) and the 95% confidence intervals (CI) were estimated. SNPs rs179247 (dominant model [GG + GA vs. AA]: OR = 0.66, 95%CI: 0.61-0.73, P = 0.000, I(2) = 0%) and rs12101255 (dominant model [TT + TC vs. CC]: OR = 1.67, 95%CI: 1.53-1.83, P = 0.000, I(2) = 0%) were significantly associated with GD in all of the genetic models. TSHR rs12101255 and rs2268458 polymorphisms had no association between GO and GD (GD without GO). The results indicate that rs179247 and rs12101255 are likely to be genetic biomarkers for GD. Further studies with different population groups and larger sample sizes are needed to confirm the genetic associations of the TSHR gene with GD/GO.

Association of IL4 and IL4R polymorphisms with multiple sclerosis susceptibility in Caucasian population: A meta-analysis

BACKGROUND

Previous studies have suggested a role for interleukin-4 (IL4) and its receptor (IL4R) gene in susceptibility to multiple sclerosis (MS), but the results remain controversial and under-powered.

OBJECTIVES

To investigate the contradictory results, we performed a meta-analysis to assess the possible association between polymorphisms of the IL4 rs2243250 (C/T), variable number of tandem repeat (VNTR) polymorphism in intron-3 (I3(709)VNTR), IL4R rs1801275 (T/C) and MS in Caucasian populations.

METHODS

A comprehensive search was conducted to identify all case-control or cohort design studies. The fixed or random effect pooled measure was selected based on the homogeneity test among studies that was evaluated with I(2). Publication bias was estimated using the Begg's and Egger's test.

RESULTS

A total of ten studies were included in the meta-analysis. The crude odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated to evaluate the association. Overall, after excluding articles deviating from Hardy-Weinberg equilibrium in controls and sensitive analysis, the meta-analysis showed a significant association between polymorphism of IL4 rs2243250 and MS susceptibility in allele model (OR=1.209, 95% CI=1.022-1.429, P=0.026) and dominant model (OR =1.225, 95% CI=1.013-1.480, P=0.036). However, no significant association was found between polymorphisms of IL4 I3(709)*VNTR, IL4R rs1801275 and MS susceptibility, respectively.

CONCLUSIONS

The meta-analysis indicates that the T allele, CT and TT genotype of polymorphism of IL4 rs2243250 (C/T) may reduce the risk of MS in Caucasian populations, while polymorphisms of IL4 I3(709)*VNTR and IL4R rs1801275 may not associated with risk of MS in Caucasian populations.