Cigarette smoking: number one enemy for Graves ophthalmopathy

A systematic review of euthyroid Graves' disease (Review)

Euthyroid Graves' Disease (EGD) is a challenging pathology, due to its atypical clinical manifestations and the absence of abnormal thyroid function. Typically, thyroid ophthalmopathy is associated with elevated thyroid hormone levels and with the presence of thyrotropin receptor antibodies (TRAb) but a low percentage of patients remain euthyroid without developing hyperthyroidism during long-term follow-up periods. Although it is considered a different pathology, it shares a lot of similarities with Graves' disease, rendering the diagnosis more difficult. It is also important to note that ophthalmopathy may be the first clinical manifestation of Graves' disease and that thyroid function examinations do not present abnormalities over a long period. Treatment choices for euthyroid disease do not differ from those described in Graves' ophthalmopathy. However, it is considered that since euthyroid patients develop milder ophthalmic symptoms and their clinical activity score is lower, they tend to have better responses to treatment. Moreover, atypical sight-threatening cases such as exposure keratopathy and dysthyroid optic neuropathy with variable responses to therapy also exist. Disease management consists of a favorable collaboration between ophthalmologists and endocrinologists because patients with EGD can develop thyroid abnormalities over time. In conclusion, the diagnosis of EGD is difficult, clinical manifestations and evolution are variables depending on several factors, including the heterogeneity of TRAb. This review aimed to identify the characteristics of this disease by reviewing the clinical studies and case reports published in previous years.

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.

Graves' Orbitopathy: Report of 82 cases

INTRODUCTION

Graves' disease (GD) is a common autoimmune disorder. Graves'orbitopathy (GO) is its most common extrathyroidal manifestation. It is rare but may reveal the disease.

AIM

To describe the demographic, clinical and therapeutic features of GO.

METHODS

We carried out a retrospective and descriptive analysis of 82 patients with GO. This study was conducted in Ophthalmology and Endocrinology departments of Taher Sfar University Hospital in Mahdia, between January 2010 and December 2017. GD patients diagnosed with GO were included.

RESULTS

The mean age was 36.17 years ± 12.81. Patients aged 19-40 years had the highest rate of GO. The male-to-female ratio was 0.49. Family history of autoimmune thyroid disease was present in 15% and associated autoimmune disease in 4% of cases. Smoking was seen in 71% of patients. The onset of GO was simultaneous with onset of GD in 45%, before in 21% and after the onset of GD in 34% of cases. GO was bilateral in 76% of patients. The most common ocular symptoms were prominent eyes (55% of patients), ocular pain (11%) and diplopia (41%). Proptosis and upper eyelid retraction were the most common clinical signs (93% and 90% respectively). Dysthyroid optic neuropathy was present in one eye, keratitis in one eye and glaucoma in five eyes. Severe disease was noted in 11% and active disease was present in 7% of patients. CT-scan and magnetic resonance imaging scan (MRI) were performed in 48% and 42% of cases respectively. Proptosis was the most common radiological sign. Thyroid dysfunction was managed with anti-thyroid medication only (59%), thyroxine replacement (37%), radioactive iodine (35%) and thyroidectomy (6%). 20% of patients received corticosteroids. One patient required immunosuppressive therapy.

CONCLUSION

GO is a complex disease, which is associated with impaired quality of life and can potentially result in sight-threatening complications. Appropriate diagnosis, convenient therapy and a regular follow-up are necessary to improve results and avoid the aesthetic and functional sequelae.

Immunomodulatory effect of vitamin D and its potential role in the prevention and treatment of thyroid autoimmunity: a narrative review

The main role of vitamin D is to control mineral homeostasis. However, recent studies suggested the existence of a number of extraskeletal effects. Among the latter, preclinical studies provided consistent data on the involvement of vitamin D in innate and adaptive immunity and autoimmunity. Molecular biology studies showed that both vitamin D receptor and vitamin D enzymatic complexes are expressed in a large number of cells and tissues unrelated to mineral homeostasis. In contrast, only a few randomized clinical trials in humans investigated the possible role of vitamin D in the prevention or treatment of immunological disorders. In this regard, low serum vitamin D levels have been reported in observational trials in human autoimmune disorders. The aim of the present paper was to review the potential implications of vitamin D in immune modulation, with special focus on thyroid autoimmune disorders.

Epidemiology, Natural History, Risk Factors, and Prevention of Graves' Orbitopathy

GO is the most frequent extrathyroidal manifestation of Graves' disease, although it may rarely occur in euthyroid/hypothyroid patients with chronic autoimmune thyroiditis. It is a relatively infrequent disorder, and men tend to have more severe ocular involvement at an older age. The prevalence of GO is lower than in the past among patients with recent onset Graves' hyperthyroidism, and moderate-to-severe forms requiring aggressive treatments are no more than 5-6% of all cases of GO. After an initial inflammatory (active) phase and a phase of stabilization (plateau phase), GO tends to improve and eventually inactivates (inactive or burnt-out phase). Minimal-to-mild GO often remits spontaneously, but complete restitutio ad integrum almost never occurs when GO is more than mild. Several risk factors contribute to its development on a yet undefined genetic background. Cigarette smoking is the most important of them. Early diagnosis, control and removal of modifiable risk factors, early treatment of mild forms of GO may effectively limit the risk of progression to more severe forms, which have a profound and dramatic impact on the quality of life of affected individuals, and remain a therapeutic challenge, often requiring long-lasting and multiple medical and surgical therapies.

The association between cigarette smoking and serum thyroid stimulating hormone, thyroid peroxidase antibodies and thyroglobulin antibodies levels in Chinese residents: A cross-sectional study in 10 cities

Objectives

Although several studies have shown that cigarette smoking is associated with thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb), the exact relationship between smoking and thyroid function is controversial. As little is known about the effects of smoking on TSH, TPOAb and TgAb in Chinese residents. This study aimed to evaluate the association between cigarette smoking and TSH, TPOAb and TgAb in ten-city residents of China.

Study design

This was a population-based cross-sectional study.

Methods

In this cross-sectional study, 15,181 subjects from ten major cities of China were investigated. Data regarding demographic characteristics, smoking status and consumption of iodine status were collected using in-person interviews based on a self-designed structured questionnaire. Serum concentrations of TSH, TPOAb and TgAb were measured using electrochemiluminescence immunoassays. Univariate analysis and multivariate linear stepwise regression analyses were used to analyze the data.

Results

The regular smokers had lower concentrations of TSH, TPOAb and TgAb than occasional smokers, former smokers and never smokers. Multivariate analysis demonstrated that regular smoking was associated with the decreased concentrations of TSH (β = -0.178), TPOAb (β = -0.287) and TGAb (β = -0.453) after adjusting other factors. Furthermore, daily smoking number was significantly associated with the decreased level of TSH (β = -0.045) and TPOAb(β = -0.080), and smoking duration was associated with the decreased TSH level (β = -0.030).

Conclusions

Our findings suggest that cigarette smoking is related to a significant decline in the concentrations of TSH, TPOAb and TgAb. In addition, daily smoking number and long-term smoking decrease serum TSH and TPOAb levels. Cigarette smoking plays a significant role in the development of thyroid dysfunction.

Teprotumumab, an insulin-like growth factor-1 receptor antagonist antibody, in the treatment of active thyroid eye disease: a focus on proptosis

Thyroid eye disease is a disabling autoimmune disease associated with orbital inflammation and tissue remodeling which can result in significant proptosis, leading to visual alterations and is potentially sight threatening. Current evidence indicates that autoantibodies to the insulin-like growth factor 1 receptor (IGF-1R), along with the thyroid-stimulating hormone receptor (TSHR), mediate the pathogenesis in susceptible individuals. Teprotumumab, a monoclonal IGF-1R antagonist, has demonstrated previously in a 24 week, randomized, controlled trial to produce significant changes in composite outcomes of proptosis and clinical activity score as compared with placebo. Further examination of the proptosis results reported here, indicate that the proptosis outcome (≥ 2 mm reduction) was met in 71.4% of the teprotumumab-treated patients as compared with 20% of the placebo-treated patients (p < 0.001). Additionally, the proptosis benefit was observed early in the trial (study week 6), and all individual patients demonstrated some benefit at week 24. Improvement was noted among smokers, non-smokers, men and women, and particularly those with higher levels of proptosis at baseline. The level of proptosis reduction with teprotumumab reported here is similar to that seen with decompression surgery. If these results are confirmed in the ongoing Phase 3 trial, teprotumumab will offer an alternative to surgery and its associated complications.

Challenges in Orphan Drug Development: Identification of Effective Therapy for Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO), the ocular manifestation of Graves' disease, is a process in which orbital connective tissues and extraocular muscles undergo inflammation and remodeling. The condition seems to result from autoimmune responses to antigens shared by the thyroid and orbit. The thyrotropin receptor (TSHR), expressed at low levels in orbital tissues, is a leading candidate antigen. Recent evidence suggests that another protein, the insulin-like growth factor-I receptor (IGF-IR), is overexpressed in TAO, and antibodies against IGF-IR have been detected in patients with the disease. Furthermore, TSHR and IGF-IR form a physical and functional complex, and signaling initiated at TSHR requires IGF-IR activity. Identification of therapy for this rare disease has proven challenging and currently relies on nonspecific and inadequate agents, thus representing an important unmet need. A recently completed therapeutic trial suggests that inhibiting IGF-IR activity with a monoclonal antibody may be an effective and safe treatment for active TAO.