Increased oxidative DNA damage, lipid peroxidation, and reactive oxygen species in cultured orbital fibroblasts from patients with Graves’ ophthalmopathy: evidence that oxidative stress has a role in this disorder

The efficacy and safety of selenium supplementation versus placebo in the treatment of Graves' orbitopathy: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Selenium is a trace element crucial for thyroid function, and has potential therapeutic benefits in Graves' orbitopathy (GO). Therefore, we aim to evaluate its efficacy and safety in GO patients to provide valuable insights into its role as a therapeutic option for this condition.

DESIGN

Systematic review and meta-analysis.

PATIENTS

GO Patients treated with selenium compared to placebo.

MEASUREMENTS

Clinical activity score (CAS), Graves' orbitopathy quality of life (GO-QOL), eye symptoms and signs, and adverse events.

RESULTS

Out of 1684 records screened, four randomised controlled trials were included. Selenium was superior at 6 months in lowering the CAS (MD = -1.27, 95% confidence interval [CI] [-1.68, -0.85], p < .0001]), improving total GO-QOL (RR = 2.54, 95% CI [1.69-3.81], p < .00001), and improving the visual and the psychological functioning scores (MD = 10.84, 95% CI [4.94-16.73], p = .003), (MD = 12.76, 95% CI [8.51-17.00], p < .00001) respectively. Similarly, it significantly improved these outcomes at 12 months. It also showed a significant decrease in the palpebral aperture at 6 months (MD = -1.49, 95% CI [-2.90, -0.08], p = .04). However, no significant differences were observed in proptosis, soft tissue involvement, ocular motility, and adverse effects.

CONCLUSIONS

Selenium is effective in reducing CAS and improving the palpebral aperture and GO-QOL in patients with GO. Additionally, it is safe and has promising therapeutic implications. However, further research is needed to validate its long-term efficacy and safety.

A Review of Pathophysiology and Therapeutic Strategies Targeting TGF-β in Graves' Ophthalmopathy

TGF-β plays a pivotal role in the pathogenesis of GO by promoting orbital tissue remodeling and fibrosis. This process involves the stimulation of orbital fibroblasts, leading to myofibroblast differentiation, increased production of inflammatory mediators, and hyaluronan accumulation. Studies have elucidated TGF-β's role in driving fibrosis and scarring processes through both canonical and non-canonical pathways, particularly resulting in the activation of orbital myofibroblasts and the excessive accumulation of extracellular matrix. Additionally, recent in vitro and in vivo studies have been summarized, highlighting the therapeutic potential of targeting TGF-β signaling pathways, which may offer promising treatment interventions for GO. This review aims to consolidate the current understanding of the multifaceted role of TGF-β in the molecular and cellular pathophysiology in Graves' ophthalmopathy (GO) by exploring its contributions to fibrosis, inflammation, and immune dysregulation. Additionally, the review investigates the therapeutic potential of inhibiting TGF-β signaling pathways as a strategy for treating GO.

Thyroid-associated ophthalmopathy: the role of oxidative stress

Thyroid-associated ophthalmopathy (TAO) is an autoimmune condition affecting the eyes, characterized by proptosis, extraocular muscle involvement, and in severe cases, vision impairment including diplopia, optic neuropathy, and potential blindness. The exact etiology of TAO remains elusive; however, increased oxidative stress and decreased antioxidant capacity are pivotal in its pathogenesis. Elevated oxidative stress not only directly damages orbital tissues but also influences thyroid function and autoimmune responses, exacerbating tissue destruction. This review explores the role of oxidative stress in TAO, elucidates its mechanisms, and evaluates the efficacy and limitations of antioxidant therapies in managing TAO. The findings aim to enhance understanding of oxidative stress mechanisms in TAO and propose potential antioxidant strategies for future therapeutic development.

Redox mechanisms in autoimmune thyroid eye disease

Thyroid eye disease (TED) is an autoimmune condition affecting the orbit and the eye with its adnexa, often occurring as an extrathyroidal complication of Graves' disease (GD). Orbital inflammatory infiltration and the stimulation of orbital fibroblasts, triggering de novo adipogenesis, an overproduction of hyaluronan, myofibroblast differentiation, and eventual tissue fibrosis are hallmarks of the disease. Notably, several redox signaling pathways have been shown to intensify inflammation and to promote adipogenesis, myofibroblast differentiation, and fibrogenesis by upregulating potent cytokines, such as interleukin (IL)-1β, IL-6, and transforming growth factor (TGF)-β. While existing treatment options can manage symptoms and potentially halt disease progression, they come with drawbacks such as relapses, side effects, and chronic adverse effects on the optic nerve. Currently, several studies shed light on the pathogenetic contributions of emerging factors within immunological cascades and chronic oxidative stress. This review article provides an overview on the latest advancements in understanding the pathophysiology of TED, with a special focus of the interplay between oxidative stress, immunological mechanisms and environmental factors. Furthermore, cutting-edge therapeutic approaches targeting redox mechanisms will be presented and discussed.

Causality of blood metabolites and metabolic pathways on Graves' disease and Graves' ophthalmopathy: a two-sample Mendelian randomization study

OBJECTIVES

There is ample that metabolic dysregulation is involved in Graves' disease (GD) and Graves' ophthalmopathy (GO). Recent studies have identified numerous metabolites associated with GD and GO. However, the causal impact of metabolites on GD and GO remains to be investigated.

METHODS

This two-sample Mendelian randomization (MR) analysis investigated the causal relationships between 486 blood metabolites and GD and GO. Sensitivity analysis was also performed to examine heterogeneity and pleiotropy.

RESULTS

MR analysis showed that 9 and 13 metabolites were associated with GD and GO, respectively, each meeting the nominal significance criteria (inverse variance weighted, p < 0.05). Additionally, four metabolic pathways were identified for each condition using network-based MetaboAnalyst 5.0.

CONCLUSIONS

The metabolites and pathways discovered in this study could serve as circulating metabolic biomarkers for clinical screening and prevention of GD and GO. They can be also used for further studies on the mechanisms and drug targets in GD and GO.

Lipids and the hallmarks of ageing: From pathology to interventions

Lipids are critical structural and functional architects of cellular homeostasis. Change in systemic lipid profile is a clinical indicator of underlying metabolic pathologies, and emerging evidence is now defining novel roles of lipids in modulating organismal ageing. Characteristic alterations in lipid metabolism correlate with age, and impaired systemic lipid profile can also accelerate the development of ageing phenotype. The present work provides a comprehensive review of the extent of lipids as regulators of the modern hallmarks of ageing viz., cellular senescence, chronic inflammation, gut dysbiosis, telomere attrition, genome instability, proteostasis and autophagy, epigenetic alterations, and stem cells dysfunctions. Current evidence on the modulation of each of these hallmarks has been discussed with emphasis on inherent age-dependent deficiencies in lipid metabolism as well as exogenous lipid changes. There appears to be sufficient evidence to consider impaired lipid metabolism as key driver of the ageing process although much of knowledge is yet fragmented. Considering dietary lipids, the type and quantity of lipids in the diet is a significant, but often overlooked determinant that governs the effects of lipids on ageing. Further research using integrative approaches amidst the known aging hallmarks is highly desirable for understanding the therapeutics of lipids associated with ageing.

Oxidative Stress: A Suitable Therapeutic Target for Optic Nerve Diseases?

Optic nerve disorders encompass a wide spectrum of conditions characterized by the loss of retinal ganglion cells (RGCs) and subsequent degeneration of the optic nerve. The etiology of these disorders can vary significantly, but emerging research highlights the crucial role of oxidative stress, an imbalance in the redox status characterized by an excess of reactive oxygen species (ROS), in driving cell death through apoptosis, autophagy, and inflammation. This review provides an overview of ROS-related processes underlying four extensively studied optic nerve diseases: glaucoma, Leber's hereditary optic neuropathy (LHON), anterior ischemic optic neuropathy (AION), and optic neuritis (ON). Furthermore, we present preclinical findings on antioxidants, with the objective of evaluating the potential therapeutic benefits of targeting oxidative stress in the treatment of optic neuropathies.

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

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

Inhibition of Xanthine Oxidase Protects against Diabetic Kidney Disease through the Amelioration of Oxidative Stress via VEGF/VEGFR Axis and NOX-FoxO3a-eNOS Signaling Pathway

Xanthine oxidase (XO) is an important source of reactive oxygen species. This study investigated whether XO inhibition exerts renoprotective effects by inhibiting vascular endothelial growth factor (VEGF) and NADPH oxidase (NOX) in diabetic kidney disease (DKD). Febuxostat (5 mg/kg) was administered to streptozotocin (STZ)-treated 8-week-old male C57BL/6 mice via intraperitoneal injection for 8 weeks. The cytoprotective effects, its mechanism of XO inhibition, and usage of high-glucose (HG)-treated cultured human glomerular endothelial cells (GECs) were also investigated. Serum cystatin C, urine albumin/creatinine ratio, and mesangial area expansion were significantly improved in febuxostat-treated DKD mice. Febuxostat reduced serum uric acid, kidney XO levels, and xanthine dehydrogenase levels. Febuxostat suppressed the expression of VEGF mRNA, VEGF receptor (VEGFR)1 and VEGFR3, NOX1, NOX2, and NOX4, and mRNA levels of their catalytic subunits. Febuxostat caused downregulation of Akt phosphorylation, followed by the enhancement of dephosphorylation of transcription factor forkhead box O3a (FoxO3a) and the activation of endothelial nitric oxide synthase (eNOS). In an in vitro study, the antioxidant effects of febuxostat were abolished by a blockade of VEGFR1 or VEGFR3 via NOX-FoxO3a-eNOS signaling in HG-treated cultured human GECs. XO inhibition attenuated DKD by ameliorating oxidative stress through the inhibition of the VEGF/VEGFR axis. This was associated with NOX-FoxO3a-eNOS signaling.

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.

Optic nerve head optical coherence tomography angiography findings in patients with thyroid eye disease: a case-control study

Background

To evaluate changes in the vessel density (VD) of the optic nerve head (ONH) microvasculature in thyroid eye disease (TED) using optical coherence tomography angiography (OCTA). This study aimed to applicate the OCTA as a noninvasive modality in screening TED patients to assess sub-clinical changes.

Methods

In a cross-sectional study, the control group patients were healthy individuals with no ocular abnormalities and were euthyroid. All patients with TED had clinical features of the disease. We divided them into two groups using the clinical activity score (CAS). Patients with CAS scores 0–2 were categorized as group A, and scores three or more as group B. All vessels (AV) and small vessels (SV) VD inside disc and radial peripapillary capillary network were measured using the ONH-OCTA.

Results

We evaluated 29 patients with TED and 28 healthy controls. The mean whole image AV VD (mean ± SD: 56.33 ± 2.56, p-value = 0.17) and the mean whole image SV VD (mean ± SD: 49.94 ± 2.56, p-value = 0.16) in the TED group had no statically significant difference compared with the control group (AV mean ± SD: 57.20 ± 20.22, SV mean ± SD: 50.84 ± 2.23). We found a non-significant decrease in AV and SV radial peripapillary capillary VD in the TED group. There was a significant decrease in the mean whole image AV VD (mean ± SD: 54.83 ± 3.07, p-value = 0.005) and the mean whole image SV VD (mean ± SD: 48.60 ± 3.18, p-value = 0.013) in CAS group B compared to group A (AV mean ± SD: 57.45 ± 1.33, SV mean ± SD: 50.95 ± 1.37).

Conclusion

Our study showed non-significant ONH vascular alterations in patients with TED, including reduced VD of ONH in the radial peripapillary capillary. Patients with higher CAS scores had a more noticeable decrease in ONH microvasculature.

A Systematic Review on the Role of Antioxidants in Thyroid Eye Disease

Purpose

To systematically review the role of antioxidants in management of patients with thyroid eye disease (TED).

Methods

A literature search of the electronic databases was performed without restrictions on the date of publication till the end of March 2021, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Clinical trials, case-control studies, cohorts, case series, case reports, and experimental (including in vitro) studies in the English language were included. The primary outcome in human studies was improvement in severity, activity scores, and/or quality of life scores. There was a decrease in the level of H2O2-dependent oxidative stress, Hyaluronic acid release, reactive oxygen species, cell proliferation, or antifibrotic/antiproliferative actions in the in vitro studies.

Results

Out of 374 initially screened articles, 157 studies were selected, the full texts of 82 were reviewed, and 14 papers were finally included. There were 4 clinical and 10 in vitro studies from 1993 to 2018. While β-carotene, retinol, Vitamin E, Vitamin C, melatonin, resveratrol, N-acetyl-l-cysteine, and quercetin showed some efficacy in in vitro studies; allopurinol, nicotinamide, pentoxifylline, and selenium (Se) were effective in both clinical and experimental reports. Se was the only recommended antioxidant based on one high-level randomized controlled trial.

Conclusion

While different antioxidants could potentially be effective in the management of TED, no strong recommendation for any or combination of antioxidants could be made to be implemented in the daily practice.

The Role of Oxidative Stress and Therapeutic Potential of Antioxidants in Graves' Ophthalmopathy

Graves’ ophthalmopathy (GO) is the most common extrathyroidal manifestation of Graves’ disease. It is characterized initially by an inflammatory process, followed by tissue remodeling and fibrosis, leading to proptosis, exposure keratopathy, ocular motility limitation, and compressive optic neuropathy. The pathogenic mechanism is complex and multifactorial. Accumulating evidence suggests the involvement of oxidative stress in the pathogenesis of GO. Cigarette smoking, a major risk factor for GO, has been shown to induce reactive oxygen species (ROS) generation and oxidative damage in GO orbital fibroblasts. In addition, an elevation in ROS and antioxidant enzymes is observed in tears, blood, and urine, as well as orbital fibroadipose tissues and fibroblasts from GO patients. In vitro and in vivo studies have examined the efficacy of various antioxidant supplements for GO. These findings suggest a therapeutic role of antioxidants in GO patients. This review summarizes the current understanding of oxidative stress in the pathogenesis and potential antioxidants for the treatment of GO.

The role of oxidative stress in the pathogenesis of Graves’ orbitopathy

Graves’ disease (GD) is a chronic autoimmune condition in which the anti-thyroid stimulating hormone receptor antibodies (TRAb) activate the thyrotropin receptor (TSHR) located on thyrocytes, leading to excessive thyroid hormone production. TSHR is also expressed in extrathyroidal tissues, in particular, within the orbit. The serum levels of TRAb correlate with the severity and activity of thyroid orbitopathy (TO). TO is the most common extrathyroidal manifestation of GD. It is an autoimmune inflammation of orbital tissues, that is, extraocular muscles, orbital adipose tissue or a lacrimal gland. Increased orbital fibroblast and adipocyte proliferation, overproduction of glycosaminoglycans, as well as extraocular muscle oedema, result in increased orbital tissue volume and trigger the onset of TO symptoms. The pathophysiology of TO is complex and has not been fully unexplained to date. Orbital fibroblasts show expression of the TSHR, which is the main target of autoimmunity. It has been hypothesised that T-cell activation induced by orbital receptor stimulation by the target antibody results in orbital tissue infiltration, triggering a cascade of events which leads to the production of cytokines, growth factors and reactive oxygen species (ROS). ROS cause damage to many components of the cell: the cell membrane through the peroxidation of lipids and proteins leading to a loss of their function and enzymatic activity. Oxidative stress leads to the activation of the antioxidant system, which operates through two mechanisms: enzymatic and non-enzymatic. Assessment of the concentration of oxidative stress markers and the concentration or activity of anti-oxidative system parameters enables the evaluation of oxidative stress severity, which in the future may be utilized to assess treatment efficacy and prognosis in patients with active OT.

The Effect of Smoking on Mitochondrial Biogenesis in Patients With Graves Ophthalmopathy

PURPOSE

To evaluate the effects of cigarette smoking on oxidative stress (OS) and mitochondrial biogenesis related parameters in patients Graves Ophthalmopathy (GO).

METHODS

Patients with moderate-to-severe GO according to the European Group on Graves Orbitopathy (EUGOGO) criteria were prospectively enrolled in this study. Age- and sex-matched healthy volunteers who applied to outpatient clinic due to refractive problems consisted the control group. Participants were divided into 4 groups based on their diagnosis and smoking status: group 1 (n = 30) smoker GO patients, group 2 (n = 30) nonsmoker GO patients, group 3 (n = 30) smoker healthy controls, and group 4 (n = 30) nonsmoker healthy controls. In the sera, total antioxidant status, total oxidant status and OS index values, peroxisome proliferator-activated receptor-γ coactivator 1-α, mitochondrial transcriptional factor A levels, and paraoxonase-1 enzyme activity were evaluated.

RESULTS

Total oxidant status and OS index values were the highest in group 1 compared to other groups (p = 0.031, p = 0.042; respectively). There was no statistically significant difference in total antioxidant status and peroxisome proliferator-activated receptor-γ coactivator 1α levels among the groups (p = 0.521, p = 0.388; respectively). Paraoxonase-1 enzyme activity was the lowest in group 1 and highest in group 4 (p = 0.024). The levels of mitochondrial transcriptional factor A was the lowest in group 1 compared to other groups (p = 0.012).

CONCLUSIONS

Cigarette smoking in GO patients seems to be a risk factor that increases OS, and therefore, it may have an unfavorable impact on the mitochondrial biogenesis.

Selenium in the Treatment of Graves' Hyperthyroidism and Eye Disease

Based on the role of oxidative stress in the pathogenesis of Graves' hyperthyroidism (GH) and Graves' Orbitopathy (GO), a therapy with the antioxidant agent selenium has been proposed and a number of studies have been performed, both in vitro and in vivo. In GH, reactive oxygen species (ROS) contribute to the thyroid and peripheral tissues damage. In GO, tissue hypoxia, as well as ROS, are involved in the typical changes that occur in fibroadipose orbital tissue and the perimysium of extraocular muscles. Antioxidants have been proposed to improve the effects of antithyroid drugs in GH patients, as well as the remodeling of orbital tissues in patients with GO. Here, we reviewed the literature on the possible beneficial effects and clinical use of selenium in the management of patients with GH and GO. A randomized clinical trial on the use of selenium in patients with mild GO provided evidence for a beneficial effect; no data are available on more severe forms of GO. Although the real effectiveness of selenium in patients with GH remains questionable, its use in the management of mild GO is generally believed to be beneficial, and selenium administration has been included in the clinical practice for the patients with mild eye disease.

Oxidative Stress in Graves Disease and Graves Orbitopathy

Oxidative stress is involved in the pathogenesis of Graves hyperthyroidism (GH) and Graves orbitopathy (GO) and an antioxidant approach has been proposed for both. In GH, a disbalance of the cell redox state is associated with thyroid hyperfunction and antithyroid medications may reduce oxidative stress. Tissue hypoxia participates in the pathogenesis of GO, and oxygen free radicals are involved in the typical changes of orbital tissues as reported by in vitro and clinical studies. Antioxidant agents, especially selenium, have been proposed as a therapeutic option for GH and GO. A clinical study regarding the use of selenium in mild GO has provided evidence for a beneficial effect in the short term, even though its beneficial effects in the long term are still to be investigated. In addition to selenium, a protective role of other antioxidant agents, i.e., quercetin, enalapril, vitamin C, N-acetyl-L-cysteine and melatonin has been suggested by in vitro studies, although clinical studies are lacking. Here, we review the role of oxidative stress and antioxidant agents in GH and GO.

The Effect of Immunosuppression on Selected Antioxidant Parameters in Patients with Graves' Disease with Active Thyroid-Associated Orbitopathy

BACKGROUND AND STUDY AIMS

Thyroid-associated orbitopathy, the most common extrathyroidal manifestation of Graves' disease, is an autoimmune inflammation of orbital soft tissue. We report the study assessing the effect of immunosuppressive treatment with methylprednisolone on selected antioxidant parameters in patients with Graves' disease with active thyroid-associated orbitopathy.

PATIENTS AND METHODS

Activity and serum levels of selected antioxidant parameters as well as lipid peroxidation products were determined in a group of 56 patients with active thyroid-associated orbitopathy at three time-points: at baseline, after the discontinuation of intravenous methylprednisolone treatment and at 3 months after the discontinuation of additional oral methylprednisolone treatment. A control group consisted of 20 healthy age- and sex-matched volunteers.

RESULTS

We found an increased activity of superoxide dismutase and glutathione peroxidase and increased serum levels of uric acid, malondialdehyde and conjugated dienes, as well as a reduced activity of paraoxonase-1 and reduced serum vitamin C level in the study group at baseline. Systemic intravenous and oral methylprednisolone therapy led to normalization of activity and concentration of the most studied parameters.

CONCLUSION

Results of our study confirmed that oxidative stress is one of the factors involved in the pathogenesis of thyroid-associated orbitopathy and the methyloprednisolone treatment is effective in reducing both clinical symptoms and oxidative stress in patients with this disease.

Resveratrol ameliorates renal damage by inhibiting oxidative stress-mediated apoptosis of podocytes in diabetic nephropathy

Diabetic nephropathy (DN) is the major cause of end-stage renal disease. Resveratrol (RSV) has been shown to exert a renoprotective effect against DN, but despite research progress, the protective mechanisms of RSV have not been fully elucidated. Here, we demonstrated that RSV relieved a series of pathological characteristics of DN and attenuated oxidative stress and apoptosis in the renal tissues of diabetic (db/db) mice. In addition, RSV inhibited oxidative stress production and apoptosis in human podocytes exposed to high glucose. Furthermore, inhibition of reactive oxygen species generation by reactive oxygen species scavengers N-acetylcysteine and 2,2,6,6-tetramethyl-1-piperidinyloxy had the same anti-apoptosis effects on podocytes as did RSV. Finally, we found that 5' adenosine monophosphate-activated protein kinase (AMPK) was activated by RSV in db/db mice and podocytes exposed to high glucose. The protective effects of RSV on podocytes were suppressed by Compound C, a pharmacological inhibitor of AMPK. Together, our results indicate that RSV effectively attenuated renal damage by suppressing oxidative stress-mediated apoptosis of podocytes, which was dependent on AMPK activation. This study revealed a possible mechanism to protect podocytes against apoptosis in DN.

The potential health benefits of dietary natural plant products in age related eye diseases

In the past decade, there has been a tremendous increase in the number of cases of age-related eye diseases such as age-related macular degeneration (AMD), cataract, diabetic retinopathy and glaucoma. These diseases are the leading causes of visual impairment and blindness all over the world and are associated with many pathological risk factors such as aging, pollution, high levels of glucose (hyperglycaemia), high metabolic rates, and light exposure. These risk factors lead to the generation of uncontrollable reactive oxygen species (ROS), which causes oxidative stress. Oxidative stress plays a crucial role in the pathogenesis of age-related eye diseases through the activation of nuclear factor kappa B (NF-κB), vascular endothelial growth factor (VEGF), and lipid peroxidation, which leads to the production of inflammatory cytokines, angiogenesis, protein and DNA damages, apoptosis that causes macular degeneration (AMD), cataract, diabetic retinopathy and glaucoma. This review provides updated information on the beneficial effects of dietary natural plant products (DPNPs) against age-related eye diseases. In this review, supplementation of DPNPs demonstrated preventive and therapeutic effects on people at risk of or with age-related eye diseases due to their capacity to scavenge free radicals, ameliorate inflammatory molecules, neutralize the oxidation reaction that occurs in photoreceptor cells, decrease vascular endothelial growth factor and the blood-retinal barrier and increase the antioxidant defence system. However, further experiments and clinical trials are required to establish the daily doses of DPNPs that will safely and effectively prevent age-related eye diseases.

Platycarya strobilacea leaf extract protects mice brain with focal cerebral ischemia by antioxidative property

The leaf extract of Platycarya strobilacea (PSL) has long been recognized as possessing various health-promoting activities. However, information on its possible protective effects against ischemic stroke is currently lacking. Here, using a mouse model of focal cerebral ischemia (fCI), we studied the protective potential of an oral supplement of PSL. Mice were randomly divided into four groups: SO, a group subjected to a sham-operation; VEH, pretreated with distilled water and subjected to middle cerebral artery occlusion and reperfusion (MCAO/R); PSL-L and PSL-H, pretreated with low (20 mg/kg) and high (100 mg/kg) doses of PSL, respectively, and subjected to the MCAO/R procedure. PSL was administered via an oral route daily for 8 days prior to surgery. We then measured the infarct volumes and sensorimotor deficits and studied the underlying antioxidant mechanisms by quantifying apoptosis, reactive oxygen species (ROS) generation, oxidative damages, and antioxidant enzymes in the ischemic cortex. The results showed a marked attenuation in infarct volume and sensorimotor deficits in both the PSL-L and PSL-H groups when compared with VEH. The terminal deoxynucleotidyl transferase dUTP nick end labeling and the immunohistochemical detection of the cleaved caspase-3 revealed that PSL could reduce cellular apoptosis in the ischemic lesion in a dose-dependent manner. The dihydroethidium-fluorescence, 4-hydroxynonenal, and 8-hydroxyl-2'-deoxyguanosine immunoreactivities in the ischemic lesion were markedly attenuated in the PSL-L group compared with the VEH group, indicating that PSL could attenuate ROS generation and the associated oxidative damage in the ischemic cortex. Finally, western blot results indicated that PSL can upregulate levels of heme oxygenase-1 (HO-1), an antioxidant enzyme, in the lesion area. Together, these results suggest that PSL can exert protective effects against fCI, and the mechanism may involve HO-1 upregulation.

Antioxidant Therapy in Graves' Orbitopathy

The balance of the cell redox state is a key point for the maintenance of cellular homeostasis. Increased reactive oxygen species (ROS) generation leads to oxidative damage of tissues, which is involved in the development of several diseases, including autoimmune diseases. Graves' Orbitopathy (GO) is a disfiguring autoimmune-related condition associated with Graves' Disease (GD). Patients with active, moderate-to-severe GO, are generally treated with high doses intravenous glucocorticoids (ivGCs) and/or orbital radiotherapy. On the contrary, up to recently, local ointments were the treatment most frequently offered to patients with mild GO, because the risks related to ivGCs does not justify the relatively poor benefits expected in mild GO. However, a medical treatment for these patients is heavily wanted, considering that GO can progress into more severe forms and also patients with mild GO complain with an impairment in their quality of life. Thus, based on the role of oxidative stress in the pathogenesis of GO, a therapy with antioxidant agents has been proposed and a number of studies have been performed, both in vitro and in vivo, which is reviewed here.

Thiol-disulfide homeostasis as an oxidative stress marker in patients with Graves' ophthalmopathy

Purpose: To evaluate thiol-disulfide homeostasis (TDH) and its relationship with clinical findings in patients with Graves' ophthalmopathy (GO). Methods: This study included 52 patients with GO and 34 healthy controls. Tests of TDH were conducted using the novel automated spectrophotometric method. Clinical activity score (CAS) and ophthalmopathy index were evaluated and relationships with native thiol, disulfide levels and disulfide/native thiol % ratios were analyzed. Results: The mean plasma native thiol levels in GO patients were significantly lower than that of normal controls (p = 0.013) . The mean plasma disulfide levels and disulfide/native thiol % ratio were found to be significantly higher in GO patients than in controls (p = 0.041, p = 0.022; respectively). The mean native thiol levels of active GO patients (n = 24) were significantly lower than that of patients with inactive GO (n = 28) (p = 0.044). The mean disulfide levels and disulfide/native thiol % ratios of active GO patients were significantly higher than that of patients with inactive GO (p = 0.034, p = 0.001; respectively). There was a negative correlation between native thiol and CAS (r = -0.532, p = 0.001) and a positive correlation between disulfide/native thiol % ratio and CAS (r = 0.601, p < 0.001). Conclusions: The impairment of TDH indicates the presence of oxidative stress in moderate-to-severe GO, particularly in active GO and smokers.

Oxidative stress markers in tears of patients with Graves' orbitopathy and their correlation with clinical activity score

Background

To investigate the concentrations of oxidative stress markers, 8-hydroxy-2′-deoxyquanosine (8-OHdG) and malondialdehyde (MDA), in tears and their correlation with the clinical activity score (CAS) in patients with Graves’ orbitopathy (GO) according to disease activity.

Methods

We recruited 27 participants with inactive stage GO, 35 participants with active stage GO, and 25 healthy controls without GO. The tear concentrations of 8-OHdG and MDA were determined by enzyme-linked immunosorbent assay. The correlation between CAS and the concentrations of tear 8-OHdG and MDA were analyzed according to the disease activity in the GO patients.

Results

The levels of 8-OHdG and MDA were 56.30 ± 16.81 ng/mL and 5.39 ± 1.31 pmol/mg, respectively, in the control subjects, and 123.46 ± 22.67 ng/mL and 13.59 ± 3.93 pmol/mg, respectively, in patients with inactive stage GO, and 215.14 ± 35.61 ng/mL and 22.52 ± 4.63 pmol/mg, in patients with active stage GO. The mean concentrations of 8-OHdG and MDA were higher in patients with inactive and active stage GO compared with the control group (all P < 0.001). Furthermore, in the active stage group, tear concentrations of 8-OHdG and MDA were higher than those in the inactive stage group (all P < 0.001). The level of 8-OHdG (r = 0.676, P < 0.001) and MDA (r = 0.506, P = 0.002) correlated with CAS in the active stage GO group.

Conclusions

The concentrations of 8-OHdG and MDA in tears increased in patients with GO, especially in those in the active stage. In patients with active stage GO, CAS correlated significantly with the tear 8-OHdG and MDA levels.

Selenium in Graves Hyperthyroidism and Orbitopathy

PURPOSE

To review the in vitro and in vivo studies supporting a role of selenium for the treatment of mild Graves orbitopathy.

METHODS

Review of the current literature on the role of selenium in the management of Graves orbitopathy.

RESULTS

Graves orbitopathy (GO) is a disfiguring and disabling disorder usually observed in patients with Graves hyperthyroidism, and more rarely in patients with hypothyroid autoimmune thyroiditis or in the absence of overt thyroid dysfunction. Noninvasive treatments include intravenous glucocorticoids and orbital radiotherapy and are generally offered to patients with moderately severe GO. In contrast, patients with mild GO are generally treated only with local measures. Thus, the benefits of intravenous glucocorticoids in mild GO are limited and do not justify the risks that the treatment carries. However, a medical treatment for mild GO is heavily wanted, as a relevant proportion of patients have a significant decrease in their quality of life, and GO can progress into more severe forms. Because of the role of oxidative stress in the pathogenesis of GO, an antioxidant approach has been proposed and the antioxidant agent selenium has been shown to be effective for GO.

CONCLUSION

Studies have shown that a 6-month course of sodium selenite can improve the course of mild GO and prevent deterioration when compared with placebo.

Relative telomere length and oxidative DNA damage in hypertrophic ligamentum flavum of lumbar spinal stenosis

Background

Lumbar spinal stenosis (LSS) is a common cause of low back pain with degenerative spinal change in older adults. Telomeres are repetitive nucleoprotein DNA sequences of TTAGGG at the ends of chromosomes. Oxidative stress originates from an imbalance in pro-oxidant and antioxidant homeostasis that results in the production of reactive oxygen species (ROS). The purpose of this study was to investigate relative telomere length (RTL) and oxidative DNA damage in ligamentum flavum (LF) tissue from LSS patients.

Methods

Forty-eight patients with LSS participated in this study. Genomic DNA from non-hypertrophic and hypertrophic LF tissue were analyzed by real-time polymerase chain reaction for relative telomere length (RTL). 8-hydroxy 2'-deoxygaunosine (8-OHdG) levels were determined by using enzyme-linked immunosorbent assay. We cultivated LF fibroblast cells from patients in different ages (61, 66, and 77 years). After each cultivation cycle, we examined RTL and senescence-associated β-galactosidase (SA-β-gal) expression.

Results

The hypertrophic LF had significantly lower RTL than non-hypertrophic LF (P = 0.04). The levels of 8-OHdG were significantly higher in hypertrophic LF compared to non-hypertrophic LF (P = 0.02). With advancing cell culture passage, the number of cells in each passage was significantly lower in hypertrophic LF fibroblast cells than non-hypertrophic LF fibroblast cells. When evaluated with SA-β-gal staining, all senescent LF fibroblast cells were observed at earlier passages in hypertrophic LF compared with non-hypertrophic LF fibroblast cells.

Discussion

Our results showed that patients with LSS displayed an accelerated RTL shortening and high oxidative stress in hypertrophic LF. These findings implied that telomere shortening and oxidative stress may play roles in the pathogenesis of hypertrophic LF in lumbar spinal stenosis.

Update on Graves disease: advances in treatment of mild, moderate and severe thyroid eye disease

PURPOSE OF REVIEW

To report the most recent therapeutic advances of thyroid eye disease (TED) and offer general recommendations for management of TED.

RECENT FINDINGS

Treatment of Graves ophthalmopathy is traditionally based on the use of high doses of corticosteroids and/or radiotherapy (RT) to decrease the activity of the disease, with the subsequent proptosis, strabismus and eyelid deformites treated with different surgical procedures. In recent years, the evidence that oxidative stress plays a relevant role in exacerbating TED severity has encouraged the use of antioxydative agents such as selenium, which has shown a capacity in limiting the disease progression. In addition, reports have shown the effectiveness of biological immunosuppressive agents in the management of TED. The main advantage of these medications seems to be the long lasting effects, which may reduce recurrence, and effectiveness in steroid-resistant cases. The reported increased accuracy of imaging techniques in evaluating fat and muscle volumes may provide useful information for surgical management.

SUMMARY

The use of selenium, in mild TED, seems to limit disease progression without carrying the risk of relevant side-effects. Biological agents may provide an effective and long lasting block of the inflammatory activity of TED, with a possible lower risk of recurrence and reduction in the need for surgical intervention in moderate-to-severe disease. The accurate evaluation of fat and muscle volume, using a recently published algorithm for imaging, gives relevant information for preoperative assessment, allowing the customization of orbital decompression.

An update on thyroid-associated ophthalmopathy in children and adolescents

BACKGROUND

Risk of developing thyroid-associated ophthalmopathy (TAO) in children and adolescents is similar or may be even slightly higher than in adults. The aim of this article is to review and summarize current knowledge regarding diagnostic and therapeutic measures in pediatric TAO.

CONTENT

MEDLINE and EMBASE papers were searched using the terms 'pediatric Graves' ophthalmopathy' 'pediatric Graves' orbitopathy', 'thyroid-associated ophthalmopathy in childhood and adolescence' from the year 1970 to December 2015.

SUMMARY

TAO usually accompanies hyperthyreosis in Graves' disease, but may also occur in patients with hypothyreosis due to chronic lymphocytic thyroiditis (Hashimoto's disease) or in euthyroid patients. Current information regarding epidemiology, pathogenesis, symptoms and treatment of TAO in children and adolescents is presented. The course of the disease is usually mild, eye disturbances often regress after restoring euthyroidism and a 'wait and see' policy is appropriate in the majority of patients. In rare cases, sight-threatening complications [dysthyroid optic neuropathy (DON) or corneal breakdown] may develop and immediate surgical intervention might become necessary.

OUTLOOK

Close cooperation between pediatric endocrinologists and opthalmologists is extremely important to ensure best care and quality of life in patients with thyroid gland dysfunction. Further investigations on pathogenesis and course of TAO in children and adolescents should be performed for better management of this disease in this group of patients.

Cigarette Smoke Extract-Induced Oxidative Stress and Fibrosis-Related Genes Expression in Orbital Fibroblasts from Patients with Graves' Ophthalmopathy

Cigarette smoking is the most important risk factor for the development or deterioration of Graves' ophthalmopathy. Smoke-induced increased generation of reactive oxygen species may be involved. However, it remains to be clarified how orbital fibroblasts are affected by cigarette smoking. Our study demonstrated that Graves' orbital fibroblasts have exaggerated response to cigarette smoke extract challenge along with increased oxidative stress, fibrosis-related genes expression, especially connective tissue growth factor, and intracellular levels of transforming growth factor-β1 and interleukin-1β. The findings obtained in this study provide some clues for the impact of cigarette smoking on Graves' ophthalmopathy and offer a theoretical basis for the potential and rational use of antioxidants in treating Graves' ophthalmopathy.

Alteration of Connective Tissue Growth Factor (CTGF) Expression in Orbital Fibroblasts from Patients with Graves' Ophthalmopathy

Graves’ ophthalmopathy (GO) is a disfiguring and sometimes blinding disease, which is characterized by inflammation and swelling of orbital tissues, with fibrosis and adipogenesis being predominant features. The aim of this study is to investigate whether the expression levels of fibrosis-related genes, especially that of connective tissue growth factor (CTGF), are altered in orbital fibroblasts of patients with GO. The role of oxidative stress in the regulation of CTGF expression in GO orbital fibroblasts is also examined. By a SYBR Green-based real time quantitative PCR (RT-QPCR), we demonstrated that the mRNA expression levels of fibronectin, apolipoprotein J, and CTGF in cultured orbital fibroblasts from patients with GO were significantly higher than those of age-matched normal controls (p = 0.007, 0.037, and 0.002, respectively). In addition, the protein expression levels of fibronectin, apolipoprotein J, and CTGF analyzed by Western blot were also significantly higher in GO orbital fibroblasts (p = 0.046, 0.032, and 0.008, respectively) as compared with the control. Furthermore, after treatment of orbital fibroblasts with a sub-lethal dose of hydrogen peroxide (200 μM H₂O₂), we found that the H₂O₂-induced increase of CTGF expression was more pronounced in the GO orbital fibroblasts as compared with those in normal controls (20% vs. 7%, p = 0.007). Importantly, pre-incubation with antioxidants including N-acetylcysteine (NAC) and vitamin C, respectively, resulted in significant attenuation of the induction of CTGF in GO orbital fibroblasts in response to H₂O₂ (p = 0.004 and 0.015, respectively). Taken together, we suggest that oxidative stress plays a role in the alteration of the expression of CTGF in GO orbital fibroblasts that may contribute to the pathogenesis and progression of GO. Antioxidants may be used in combination with the therapeutic agents for effective treatment of GO.

Pathogenesis of thyroid eye disease: review and update on molecular mechanisms

Orbital changes in thyroid orbitopathy (TO) result from de novo adipogenesis, hyaluronan synthesis, interstitial oedema and enlargement of extraocular muscles. Cellular immunity, with predominantly CD4+ T cells expressing Th1 cytokines, and overexpression of macrophage-derived cytokines, perpetuate orbital inflammation. Orbital fibroblasts appear to be the major effector cells. Orbital fibroblasts express both thyrotropin receptor (TSHR) and insulin-like growth factor-1 receptor (IGF-1R) at higher levels than normal fibroblasts. TSHR expression increases in adipogenesis; TSHR agonism enhances hyaluronan production. IGF-1R stimulation leads to adipogenesis, hyaluronan synthesis and production of the chemokines, interleukin (IL)-16 and Regulated on Activation, Normal T Cell Expression and Secreted, which facilitate lymphocyte trafficking into the orbit. Immune activation uses a specific CD40:CD154 molecular bridge to activate orbital fibroblasts, which secrete pro-inflammatory cytokines including IL-1β, IL-1α, IL-6, IL-8, macrophage chemoattractant protein-1 and transforming growth factor-β, to perpetuate orbital inflammation. Molecular pathways including adenylyl cyclase/cyclic adenosine monophosphate, phophoinositide 3 kinase/AKT/mammalian target of rapamycin, mitogen-activated protein kinase are involved in TO. The emergence of a TO animal model and a new generation of TSHR antibody assays increasingly point towards TSHR as the primary autoantigen for extrathyroidal orbital involvement. Oxidative stress in TO resulting from imbalances of the oxidation-reduction state provides a framework of understanding for smoking prevention, achieving euthyroidism and the use of antioxidants such as selenium. Progress has been made in the understanding of the pathogenesis of TO, which should advance development of novel therapies targeting cellular immunity, specifically the CD40:CD40 ligand interaction, antibody-producing B cells, cytokines, TSHR and IGF-1R and its signalling pathways. Further studies in signalling networks and molecular triggers leading to burnout of TO will further our understanding of TO.

Oxidative Stress and Upregulation of Antioxidant Proteins, Including Adiponectin, in Extraocular Muscular Cells, Orbital Adipocytes, and Thyrocytes in Graves' Disease Associated with Orbitopathy

BACKGROUND

Graves' orbitopathy (GO) is the main extrathyroidal manifestation associated with Graves' disease (GD). It is characterized by reduced eye motility due to an increased volume of orbital fat and/or of extraocular muscles (EOMs) infiltrated by fibrosis and adipose tissue. The pathogenetic mechanisms leading to fibrosis and adipogenesis are mainly based on the interaction between orbital fibroblasts and immune cells (lymphocytes and mast cells) infiltrating the GO EOMs.

METHODS

Analysis of the morphological status, oxidative stress (OS), and antioxidant defenses in the orbital muscular cells and adipocytes in GO patients compared with controls was conducted.

RESULTS

Both cell types are affected by OS, as shown by the increased expression of 4-hydroxynonenal, which leads to apoptosis in muscular cells. However, the EOMs and the adipocytes possess antioxidant defenses (peroxiredoxin 5 and catalase) against the OS, which are also upregulated in thyrocytes in GD. The expression of adiponectin (ApN) and proliferator-activated receptor gamma (PPARγ) is also increased in GO muscular cells and adipocytes. OS and antioxidant proteins expression are correlated to the level of blood antithyrotropin receptor antibodies (TSHR-Ab).

CONCLUSION

Even when TSHR-Ab level is normalized, OS and antioxidant protein expression is high in EOM muscular cells and adipocytes in GO compared with controls. This justifies a supplementation with antioxidants in active as well as chronic GO patients. Orbital muscular cells are also the sources of PPARγ and ApN, which have direct or indirect local protective effects against OS. Modulation of these proteins could be considered as a future therapeutic approach for GO.

Hypoxia increases adipogenesis and affects adipocytokine production in orbital fibroblasts-a possible explanation of the link between smoking and Graves' ophthalmopathy

AIM

To assess the effects of hypoxia on human orbital fibroblasts (OF) on adipogenesis and adipocytokine production.

METHODS

Human OF were derived from tissues obtained from patients with Graves' ophthalmopathy (GO) and from patients without known thyroid diseases undergoing blepharoplasty. The OF were cultured separately under normoxic and hypoxic conditions. Comparisons of adipocytokine concentrations using multiplex ELISA and lipid accumulation in the cells using Oil Red O staining were subsequently performed.

RESULTS

There was increased adipogenesis in OF from GO subject when exposed to hypoxic culture conditions. This was not observed in OF from normal controls. Hypoxia led to an increase in leptin and a decrease in MCP-1 secretion in OF cultures.

CONCLUSION

Hypoxia induces adipogenesis in OF and may represent a mechanism by which smoking contributes to deterioration of GO. We also found novel changes to leptin and MCP-1 production in OF cultures exposed to hypoxia suggesting important roles of these cytokines in the disease process.

Cigarette smoke extract-induced adipogenesis in Graves' orbital fibroblasts is inhibited by quercetin via reduction in oxidative stress

Cigarette smoking is known to aggravate Graves' orbitopathy (GO) severity by enhancing adipogenesis. We investigated the effect of quercetin, an antioxidant, on adipocyte differentiation induced by cigarette smoke extract (CSE) in primary cultured orbital fibroblasts (OFs) from GO patients. Freshly prepared CSE was added to the cells and H(2)O(2) was used as a positive control. Intracellular reactive oxygen species (ROS) generation and adipogenesis were measured. The expressions of proteins peroxisome proliferator-activated receptor (PPAR) γ, CCAAT-enhancer-binding proteins (C/EBP) α and β, and heme oxygenase-1 (HO-1), an antioxidant enzyme, were examined during adipogenic differentiation. In result, CSE and H(2)O(2) dose-dependently stimulated intracellular ROS production in normal and Graves' OFs. The effect of 2% CSE was similar to that of 10 μM H(2)O(2); both concentrations were noncytotoxic and were used throughout the experiment. Quercetin pretreatment reduced the ROS generation stimulated by either CSE or H(2)O(2) in preadipocyte OFs. CSE and H(2)O(2) stimulated adipocyte differentiation in cultured OFs. The addition of quercetin (50 or 100 μM) suppressed adipogenesis. Quercetin also suppressed ROS generation in differentiating OFs during adipogenesis stimulated by CSE and H(2)O(2). Additionally, the expressions of PPARγ, C/EBPα, and C/EBPβ proteins were reduced in the quercetin-treated OFs. Quercetin also reduced the CSE- and H(2)O(2)-induced upregulation of ROS and HO-1 protein in differentiated OFs and preadipocyte OFs. As shown in this study, quercetin inhibited adipogenesis by reducing ROS in vitro, supporting the use of quercetin in the treatment of GO.

Ischemia-modified albumin in patients with hyperthyroidism and hypothyroidism

BACKGROUND

The relationship between ischemia-modified albumin (IMA) and thyroid dysfunction remains uncertain. This study aimed to investigate the influence of overt hypothyroidism (Oho), overt hyperthyroidism (Ohe), and their treatments on serum IMA levels.

METHODS

A total of 35 untreated patients with Ohe, 35 untreated patients with Oho, and 35 control subjects were enrolled in the study. C-reactive protein (CRP), homocysteine (Hcy), IMA, and lipid profiles were measured and evaluated before and after treatment.

RESULTS

CRP, Hcy, and IMA levels and lipid profiles were higher in patients with Oho than in euthyroid or Ohe subjects (p<0.05). Basal IMA levels were reduced after treatments in all patients (p<0.05). In Ohe patients, serum IMA levels were positively correlated with free triiodothyronine (r=0.424, p=0.011) and free thyroxine (r=0.567, p<0.001) levels. In Oho patients, serum IMA levels were inversely correlated with free triiodothyronine (r=-0.555, p=0.001) and free thyroxine (r=-0.457, p=0.006) but positively correlated with anti-thyroid peroxidase antibody, C-reactive protein, and homocysteine levels (p<0.05). Linear regression analyses showed that free triiodothyronine was the most important factor affecting serum IMA levels in Ohe (β=0.694, p=0.019) and in Oho (β=-0.512, p=0.025).

CONCLUSIONS

IMA levels are increased in patients with thyroid dysfunction, particularly in overt hypothyroidism. Thyroid dysfunction has a significant impact on the oxidative stress status.

Oxidative stress in graves' disease

Increased reactive oxygen species (ROS) generation and the consequent oxidative damage are involved in the development of several diseases, including autoimmune diseases. Graves' disease is an autoimmune disorder characterized by hyperthyroidism and, less frequently, orbitopathy. Hyperthyroidism is characterized by increased oxidative stress. Untreated hyperthyroidism is associated with an increase of several parameters of oxidative stress and in most studies (but not all) by an increase of antioxidant defense enzymes. Restoration of euthyroidism with antithyroid drug is associated with a reversal of the biochemical abnormalities associated with oxidative stress. Animal and human studies suggest that increased ROS may directly contribute to some clinical manifestation of the disease, including orbitopathy. Antioxidants administered alone improve some clinical signs and symptoms of hyperthyroidism and, when associated with antithyroid drugs, induce a more rapid control of clinical manifestations and a faster achievement of euthyroidism. A large randomized clinical trial has shown that antioxidant supplementation (selenium) may also be beneficial for mild Graves' orbitopathy.

Reversing bladder outlet obstruction attenuates systemic and tissue oxidative stress

What's known on the subject? and What does the study add? Oxidative damage in bladder tissue and systemic oxidative biomarkers were both found to be increased in rabbits with partial bladder outlet obstruction. It is shown that the reversal of partial bladder outlet obstruction will attenuate the systemic oxidative stress.

OBJECTIVE

To investigate whether partial bladder outlet obstruction (PBOO) increases systemic oxidative stress and whether relief of PBOO could attenuate this stress.

MATERIALS AND METHODS

Surgically created PBOO in male New Zealand white rabbits was assessed after 4 weeks in one group of rabbits (n = 4), and was relieved in two additional groups of rabbits (n = 4 each) that were assessed at 4 and 8 weeks after relief of PBOO. Four sham-operated rabbits served as controls. The assessed oxidative stress biomarkers included urinary and plasma 8-hydroxy-2'-deoxyguanosine (8-OHdG) and plasma malondialdehyde (MDA), total anti-oxidant capacity (TAC) and glutathione (GSH). In addition, the copy number of mitochondrial DNA and the 8-OHdG content in bladder tissues from these rabbits were also determined at the beginning and at indicated time points in the experiments.

RESULTS

There were significant increases in both the 8-OHdG levels of urine, plasma and bladder tissue and the plasma MDA after induction of PBOO. There were also significant decreases in the TAC, in GSH levels and in mitochondrial DNA copy number in bladder tissues after PBOO. Most importantly, all of the values returned toward the control levels after the PBOO was reversed at 8 weeks.

CONCLUSION

PBOO increases systemic and oxidative stress and its reversal results in a progressive reduction of both systemic and tissue oxidative stress.

The evolving role of selenium in the treatment of graves' disease and ophthalmopathy

Graves' disease (GD) and ophthalmopathy (GO) are organ-specific autoimmune-inflammatory disorders characterized by a complex pathogenesis. The inflammatory process is dominated by an imbalance of the antioxidant-oxidant mechanism, increased production of radical oxygen species (ROS), and cytokines which sustain the autoimmune process and perpetuate the disease. Recently, selenium, which is a powerful antioxidant, has been successfully applied in patients with mild GO, slowing the progression of disease, decreasing the clinical activity score, and appreciably improving the quality of life. The mechanisms of selenium action are variable. The aim of this review is to summarize the actions of selenium in GD and GO. Selenium as selenocysteine is incorporated in selenoproteins, such as glutathione peroxidase which catalyzes the degradation of hydrogen peroxide and lipid hydroperoxide that are increasingly produced in hyperthyroidism. Moreover, selenium decreases the formation of proinflammatory cytokines, while it contributes, in synergy with antithyroid drugs, to stabilization of the autoimmune process in GD and alleviation of GO. It is now to be clarified whether enforced nutritional supplementation has the same results and whether prolonging selenium administration may have an impact on the prevention of disease.

The role of oxidative stress on the pathogenesis of graves' disease

Graves' disease is a most common cause of hyperthyroidism. It is an autoimmune disease, and autoimmune process induces an inflammatory reaction, and reactive oxygen species (ROSs) are among its products. When balance between oxidants and antioxidants is disturbed, in favour of the oxidants it is termed "oxidative stress" (OS). Increased OS characterizes Graves' disease. It seems that the level of OS is increased in subjects with Graves' ophthalmopathy compared to the other subjects with Graves' disease. Among the other factors, OS is involved in proliferation of orbital fibroblasts. Polymorphism of the 8-oxoG DNA N-glycosylase 1 (hOGG1) involved in repair of the oxidative damaged DNA increases in the risk for developing Grave's disease. Treatment with glucocorticoids reduces levels of OS markers. A recent large clinical trial evaluated effect of selenium on mild Graves' ophthalmopathy. Selenium treatment was associated with an improved quality of life and less eye involvement and slowed the progression of Graves' orbitopathy, compared to placebo.

A novel mechanism involved in the pathogenesis of Graves ophthalmopathy (GO): clathrin is a possible targeting molecule for inhibiting local immune response in the orbit

INTRODUCTION

Excessive orbital fibroblast (OF) proliferation and extracellular matrix production, as well as inflammation resulting in the expansion and remodeling of orbital tissue, are characteristic of Graves ophthalmopathy (GO). Our aim was to analyze and inhibit signaling pathways in resident OF that are involved in GO. METHODS/MAIN OUTCOME MEASURES: Primary human OF were obtained from 12 patients with active, severe GO and from 12 healthy control subjects. The cells were characterized by immunofluorescence assay and flow cytometry. Tyrosine phosphorylation of cellular proteins was determined by Western blot techniques, immunoprecipitation, and protein identity with mass spectrometry. Cell proliferation was determined by 5-bromo-2-deoxyuridine incorporation, hyaluronan (HA) production was assessed by a HA-binding protein based assay, and intracellular reactive oxygen species (ROS) were determined by the dichlorofluorescein assay. Clathrin heavy-chain (CHC) expression was inhibited with small interfering RNA technology.

RESULTS

Tyrosine phosphorylation of CHC is constitutively increased in vitro in GO-derived OF, independent of serum or other stimulating factors. The proliferative and biosynthetic capabilities (production of HA, ROS) of GO-derived OF are significantly higher than those of OF from healthy control subjects. Down-regulation of CHC expression leads to a normalization of pathologically increased proliferation and production of HA and ROS in GO-derived OFs in vitro.

CONCLUSIONS

Our findings strongly suggest that clathrin and clathrin-mediated signaling pathways are involved in the inflammatory signal transduction of OF in GO. With the identification of clathrin, we report a new potential targeting molecule for specific pharmacological inhibition of the local inflammatory response characteristic of GO.