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Evidence for thyrotropin receptor immunoreactivity in pretibial connective tissue from patients with thyroid-associated dermopathy
Abstract
Pretibial myxedema (PTM), mainly characterized by the accumulation of glycosaminoglycans in the dermis and subcutaneous tissue, is an extrathyroidal manifestation of autoimmune Graves' disease (GD), almost always associated with Graves' ophthalmopathy (GO). The thyrotropin receptor (TSH-R) has been proposed as the common target antigen in GD, GO and PTM, with evidence for receptor transcripts and/or protein in these locations. The aim of this study has been to investigate whether receptor protein is present in the pretibial tissues. Skin biopsies were obtained from two patients with PTM and two normal subjects without thyroid disease. A portion of each sample was fixed to produce semi-thin sections for Toluidine Blue or Periodic Acid Schiff (PAS) staining. The remainder was snap frozen to generate cryostat sections for immunohistochemical analysis using three monoclonal antibodies against TSH-R. In the skin from the two patients suffering from PTM, the dermis was infiltrated by inflammatory cells (lymphocytes, B cells, macrophages, mast cells) and adipocytes. The collagen fibers were dissociated by edema and by the accumulation of a PAS-positive material. Immunodetection of TSH-R produced positive staining on cells localized in the dermis, beneath the epidermis or close to the hypodermis. These cells were elongated and resembled fibroblasts. No immunoreactivity was observed in the dermis from control patients without thyroid disease. In conclusion, we have evidence for TSH-R immunoreactivity in the pretibium of patients with GD, GO and PTM. Further studies are needed to unambiguously identify the positive cells and determine whether the reactivity is due to the receptor itself or to a cross-reacting protein.
... The thyrotropin receptor (TSH-R) has been nominated as a common target antigen in Graves' ophthalmopathy (GO) and pretibial myxedema (PTM) (10)(11)(12). In previous studies, the presence of TSH-R immunoreactivity has been also reported to be involved in the muscles and adipose tissues of patients with GO and in the dermis of patients with PTM (6,10). ...
... In previous studies, the presence of TSH-R immunoreactivity has been also reported to be involved in the muscles and adipose tissues of patients with GO and in the dermis of patients with PTM (6,10). Therefore, the antigen-antibody reaction is hypothesized to result in the stimulation of fibroblasts, with a secondary release of cytokines leading to lymphocyte attraction and production of glycosaminoglycans, eventually causing tissue swelling (2,10,11). ...
... The mechanism of myxedema is not completely clear, and it is assumed that the presence of the TSHR-Ab stimulates fibroblasts, leading to glycosaminoglycans production and resulting in the engorgement of the involved tissues (10,11). Mild cases of myxedema or cases without cosmetic or local functional limitation do not require topical treatment and are usually followed up by endocrinologists. ...
Exophthalmos, myxedema and osteoarthropathy (EMO) comprise the triad known as EMO syndrome, which is rarely observed in patients with autoimmune thyroid disease. The present study reports the case of a patient with EMO, including the response of this rare combination to radiotherapy. A 48‑year‑old patient with EMO syndrome presented to the Department of Radiation Oncology, University Hospital of Muenster, eight years prior to writing with therapy‑resistant pretibial myxedema and hypertrophic osteoarthropathy of the metacarpal bones. The patient had been diagnosed with Graves' disease (GD) 26 years prior to presentation, which was treated by thyroidectomy and radioiodine therapy. Four years subsequent to the diagnosis of GD, the patient developed exophthalmos, which was treated using radiotherapy. An evident pretibial, foot and hand myxedema developed within the 10 years following the onset of orbitopathy. The skin lesions were treated using radiation therapy subsequent to the failure of multiple surgical procedures and medical treatments. Almost eight years subsequent to the administration of irradiation, no recurrence was observed on the lower right leg, nor was any recurrence on the lower left leg observed approximately four years subsequent to the completion of radiotherapy. However, an additional lesion on the left hand demonstrated slow progression following treatment with radiation therapy. The present study indicates that radiation therapy can be considered as adjuvant therapy for patients with refractory myxedema, to prevent or delay the recurrence of myxedema subsequent to surgical excision.
... About the effect of thyroid hormones on dermis, the studies have shown that hypothyroidism can cause water and mucopolysacharides deposition in dermis that causes light reflection change and so makes a yellowish skin (21). Also in Graves syndrome a common type of thyroid autoimmune diseases, hyaluronic acid aggregation increases in dermis and hypodermis that starts from papillary dermis and expends to deep areas of tissue (21,24). Also the scientists have shown that many thyroid hormone receptors are present in dermis, subepidermis or near to hypodermis showing wide effect of thyroid hormones on this area (24). ...
... Also in Graves syndrome a common type of thyroid autoimmune diseases, hyaluronic acid aggregation increases in dermis and hypodermis that starts from papillary dermis and expends to deep areas of tissue (21,24). Also the scientists have shown that many thyroid hormone receptors are present in dermis, subepidermis or near to hypodermis showing wide effect of thyroid hormones on this area (24). ...
... About hair follicle number, the previous studies showed hypothyroidism leads to decrease hair growth and hair follicle survival. In fact hypothyroidism causes hair fall and hair number decrease (24,27). This study showed hyperthyroidism accompany with hair growth and hair survival increase. ...
Objective(s): Previous studies have shown that thyroid hormones are necessary for normal development of many organs and because of the importance of skin as the largest and the most important organ in human body protection in spite of external environment, the study of thyroid hormones effects on skin development is considerable. In this survey we have tried to study the effects of maternal hypothyroidism on skin development in fetus during pregnancy and lactation by immunohistochemistry technique.
Materials and Methods: Rats were divided into 4 groups, hypothyroids, hyperthyroids, hypothyroids are treated with levothyroxin and a control group. The rat mothers were exposed to PTU with 50 mg/lit dosage and levothyroxin with 1 mg/lit dosage and PTU and levothyroxin simultaneously and with the same dosage respectively in hypothyroid, hyperthyroid and treated hypothyroids with levothyroxin groups. After 14 days, blood sample was taken from mothers, and if thyroid hormones level had change well, mating was allowed. After pregnancy and delivery, 1th day dorsal skin (as the sample for pregnancy assay) and 10th day skin (as for lactation assay) was used for immunohystochemical and morphometric studies.
Results: In this study it was observed that maternal hypothyroidism during pregnancy and lactation causes significant increase in laminin expression, in most areas of skin, and maternal hyperthyroidism during pregnancy and lactation causes significant decrease in laminin expression. Also significant decrease was observed in hair follicles number and epidermis thickness in hypothyroidism groups.
Conclusion: This study showed maternal hypothyroidism causes significant decrease in epidermis thickness and hair follicles number and it causes less hair in fetus. Also maternal hypothyroidism causes large changes in laminin expression in different parts of skin. At the same time,maternal hyperthyroidism causes opposite results. In fact, thyroid hormones regulate laminin expression negatively which means increase in thyroid hormone level, decreases laminin expression. So changes in thyroid hormones level can influence skin development significantly.
... To assess the safety of anti-TSHR CAR-T therapy, we next explored the TSHR expression level in extrathyroidal tissues. Because the presence of TSHR-specific immunoreactivity in the retro-orbital and pretibial tissues of some patients with Graves' disease has been previously reported (33,34), we first determined whether its expression was restricted to the individual's Graves' hyperthyroidism-related complications but not the healthy donors. Indeed, we did not detect the TSHR expression in all 15 retro-orbital adipose/connective tissues and 3 pretibial subcutaneous tissues from individuals without hyperthyroidism; however, we found faintly positive (1+) IHC staining of TSHR in 4/6 specimens of gastric mucosa and 2/3 cases of bladder epithelium ( Fig. 2A, Table 2, and supplemental Table 1 (28)). ...
... Moreover, as the main self-antigen, TSHR was reported to be highly expressed in the orbital and pretibial adipose/connective tissues of Graves' ophthalmopathy. However, its expression is confined to only these patients but not to normal counterparts, as confirmed by IHC, and these findings were consistent with previous reports (33,34). We tested the TSHR CAR-T safety in a xenograft mouse model of DTC and did not find any apparent toxicity in the majority of organs. ...
Background
Chimeric antigen receptor T cells （CAR-T） have been demonstrated remarkable efficacy in hematological cancers but have not yet translated in treating solid tumors. The significant hurdles limiting CAR-T therapy were due to a paucity of differentially expressed cell surface molecules on solid tumors that can be safely targeted. Here, we present thyroid-stimulating hormone receptor (TSHR) as a putative target for CAR-T therapy of differentiated thyroid cancer (DTC).
Methods
We undertook a large-scale screen on thyroid cancer tissues and multiple internal organs through bioinformatical analysis and immunohistochemistry to date TSHR expression. Using three previously described mAb, we generate three third-generation CAR-Ts. We tested anti-TSHR CAR-T in vitro activity by T-cell function and killing assay. Then we tested pre-clinical therapeutical efficacy in a xenograft mouse model of DTC and analyzed mice's physical conditions and histological abnormalities to evaluate anti-TSHR CAR-T's safety.
Results
TSHR is highly and homogeneously expressed on 90.8% (138/152) of papillary thyroid cancer, 89.2% (33/37) of follicular thyroid cancer, 78.2% (18/23) of the cervical lymph node metastases, and 86.7% of RAI-R diseases. We developed three novel anti-TSHR CAR-T from mAb M22, K1-18, and K1-70; all three CAR-Ts mediate significant anti-tumor activity in vitro. Among these, we demonstrate that K1-70 CAR-T can have therapeutical efficacy in vivo, and no apparent toxicity has been observed.
Conclusion
TSHR is a latent target antigen of CAR-T therapy for DTC. Anti-TSHR CAR-T could represent a therapeutic option for patients with local-regional relapsed or distant metastases of thyroid cancer and should be tested in carefully designed clinical trials.
... It can also involve the knees, elbows, neck, and other areas exposed to repeated pressure or trauma (3,(8)(9)(10)(11). Orbital and pretibial fibroblasts express the thyrotropin (TSH) receptor (TSH-R) and insulin-line growth factor 1 receptor, and become targeted by TSH-R sensitized T cells and/or TSH-R antibodies (TRAb), leading to the inflam-matory and infiltrative cascade of GO and PTM (12,13). The pathogenesis of PTM is characterized by fibroblast proliferation and glycosaminoglycan accumulation causing non-pitting edema, which leads to compression of dermal lymphatics and can progress to significant lymphedema (1). ...
... In the present patients, it was not possible to demonstrate a clear relationship between the duration of PTM before initiation of IVIg or RTX and response to therapy. PTM is an autoimmune disorder mediated by the interaction between TRAb and/or TSH-R sensitized T-cells and the TSH-R on dermal fibroblasts (12,13). There is clear evidence of antibody values influencing the prognosis of GO (24), but the evidence is not that convincing for PTM. ...
Background:
Severe pretibial myxedema (PTM) can be difficult to manage, highlighting the need to investigate newer therapies. Rituximab (RTX) and intravenous immunoglobulin (IVIg) have been tried in Graves' orbitopathy. Since PTM and orbitopathy share a similar underlying pathophysiology, this study aimed to explore these therapies for progressive PTM.
Methods:
The electronic database was screened for PTM patients evaluated at the Mayo Clinic, Rochester, from 2002 to 2016, and three patients who received IVIg and five who received RTX are reported. PTM pattern was classified as non-pitting edema, plaque and induration, nodular/nummular, and elephantiasis. PTM was confirmed by biopsy in six patients.
Results:
The patients' median age was 53.8 years, 75% were female, and all but one patient were either active or former smokers. All patients were euthyroid and had progressed despite various therapies prior to starting these agents. Six patients had a plaque and induration pattern, and two had a nodular pattern with elephantiasis. After therapy, six (75%) patients had PTM stability or improvement both subjectively and objectively (80% with RTX and 66% with IVIg). The three patients (one in the IVIg group and two in the RTX group) who had subjective improvement had a plaque pattern. One patient with elephantiasis had a transient response to IVIg and another had stability after RTX. Thyrotropin receptor antibody values and orbitopathy also improved in patients who demonstrated PTM improvement. No serious adverse events were reported, but one patient each had transient hypertension and injection-site thrombophlebitis after IVIg.
Conclusions:
Immunomodulation therapy was followed by PTM improvement or stability in most patients, with a slightly better response after RTX compared to IVIg. A validated response assessment instrument and larger series of patients are required to determine if the underlying disease process could be curtailed with these agents.
... Moreover, THs can stimulate the expression of laminin in various areas of skin that is an extracellular protein matrix ( Burrow, 1994;Kung, 1997;Farwell and Dubord-Tomasetti, 1999;Ahmed et al., 2008;Amerion et al., 2013). On the other hand, the maternal hypothyroidism causes several defects in the developing skin ( Holt et al., 1976;Holt and Marks, 1977;Engfeldt et al., 1982;Robert and Herrera, 1988;Peltonen et al., 2000;Daumerie et al., 2002;Safer et al., 2003;Heymann, 2008;Amerion et al., 2013): the anabolic activities in developing skin.On the other hand, the maternal hyperthyroidism can cause the opposite behavior where hyperthyroidism decreases the levels of laminin in several parts of the skin ( Billoni et al., 2000;Li et al., 2003;Amerion et al., 2013).Thus, the maternal THs cause a negative effect on the levels of fetal/neonatal laminin expression.In addition, the elevation in the aggregation of hyaluronic acid was observed in dermis and hypodermis of Graves's syndrome a common type of thyroid autoimmune diseases ( Gong et al., 1997;Daumerie et al., 2002;Heymann, 2008). On the other hand, the anabolic activities were increased in epidermis during the thyrotoxicosis ( Amerion et al., 2013). ...
... Moreover, THs can stimulate the expression of laminin in various areas of skin that is an extracellular protein matrix ( Burrow, 1994;Kung, 1997;Farwell and Dubord-Tomasetti, 1999;Ahmed et al., 2008;Amerion et al., 2013). On the other hand, the maternal hypothyroidism causes several defects in the developing skin ( Holt et al., 1976;Holt and Marks, 1977;Engfeldt et al., 1982;Robert and Herrera, 1988;Peltonen et al., 2000;Daumerie et al., 2002;Safer et al., 2003;Heymann, 2008;Amerion et al., 2013): the anabolic activities in developing skin.On the other hand, the maternal hyperthyroidism can cause the opposite behavior where hyperthyroidism decreases the levels of laminin in several parts of the skin ( Billoni et al., 2000;Li et al., 2003;Amerion et al., 2013).Thus, the maternal THs cause a negative effect on the levels of fetal/neonatal laminin expression.In addition, the elevation in the aggregation of hyaluronic acid was observed in dermis and hypodermis of Graves's syndrome a common type of thyroid autoimmune diseases ( Gong et al., 1997;Daumerie et al., 2002;Heymann, 2008). On the other hand, the anabolic activities were increased in epidermis during the thyrotoxicosis ( Amerion et al., 2013). ...
Thyroid hormones (THs) have important roles on the most developing system, particularly the developing skin and differentiation the epithelial cells like keratinocytes. In addition, thyroid receptors isoforms (TRs; α, β) can regulate the growth and differentiation of the skin and the survival of hair follicles. Also, THs can induce the epidermal growth and the keratin gene expression by increasing the epidermal growth factor receptor number (EGF). Moreover, THs can stimulate the expression of laminin in various areas of skin that is an extracellular protein matrix. On the other hand, the maternal hypothyroidism causes several defects in the developing skin: (1) decrease the thickness of epidermis; (2) diminish the number of fetal hair follicles; (3) increase the levels of laminin expression in developing skin; (4) elevate the deposition of water and mucopolysacharides in dermis (yellowish skin); (5) decrease the epidermal proliferation rate; and (6) reduce the anabolic activities in developing skin. The maternal hyperthyroidism can cause the opposite behavior where hyperthyroidism decreases the levels of laminin in several parts of the skin. Thus, the maternal THs cause a negative effect on the levels of fetal/neonatal laminin expression. Also, the anabolic activities were increased in epidermis during the thyrotoxicosis. Thus, the disorders in the thyroid functions (hypothyroidism or hyperthyroidism) during the pregnancy and lactation may disrupt the growth and differentiation of the developing skin. Additional thoughts are required to explore the effect of maternal thyroid disorders on the fetal/neonatal physiological processes.
... Indeed, TSH receptor (TSHR) detection in dermis fibroblasts and melanocytes indicates that the skin is a target of thyroid axis. [18][19][20][21] Thus, both thyroid autoimmunity and hormonal action on the TSHR could be involved in the pathogenesis of CSU. However, currently, the mechanisms involved in the relationship between CSU and thyroid disease, particularly HT, are unknown, which raises the question of whether both conditions have a cause-effect relationship or are two simultaneous autoimmune diseases. ...
... In addition, the TSHR represents one of the HT autoantigens, 13 and it is present in skin cells, suggesting that the epidermis is a TSH signaling target. [18][19][20][21] Indeed, thyroid hormones alter skin architecture and homeostasis. 9,21,34 Therefore, the purpose of this study was to evaluate ASST positivity and TSHR gene expression in ASST wheals and healthy skin of women with CSU, with and without HT. ...
Background:
Chronic spontaneous urticaria (CSU) may be associated with autoimmune thyroid diseases, and the Autologous Serum Skin Test (ASST) is an autoreactivity marker. The thyrotropin (TSH) and TSH receptor (TSHR) could play a role in the pathogenesis of CSU. The aim of this study was to evaluate ASST positivity and TSHR gene expression in healthy skin and ASST wheals in euthyroid women with CSU, with (14 patients) and without (15 patients) Hashimoto's thyroiditis (HT).
Methods:
ASST was performed and TSHR gene expression studied in wheals induced by ASST and in healthy skin.
Results:
ASST presented greater positivity (86% × 40%) and larger diameter (10.8 × 9.6 mm) in the HT group (P < 0.05). TSHR gene expression was higher in the ASST area and healthy skin of HT group (P < 0.01). Positive correlation of antibodies levels with ASST wheal measurements and TSHR gene expression was seen.
Conclusions:
Women with CSU and HT presented greater positivity and larger measurements for ASST and higher TSHR expression in the skin, suggesting association between CSU, thyroid autoimmunity, and TSHR.
... The hyperplasia of PTM manifested as hyperkeratosis and acanthosis of epidermis, dermal thickening, and hypertrichosis [18]. The phenomena were initiated by autoimmune reactions (humoral and cell-mediated immunity) to autoantigens (mainly TSHR) on the fibroblasts [32,33], fibrocytes [34], and mast cells [33]. ...
... The hyperplasia of PTM manifested as hyperkeratosis and acanthosis of epidermis, dermal thickening, and hypertrichosis [18]. The phenomena were initiated by autoimmune reactions (humoral and cell-mediated immunity) to autoantigens (mainly TSHR) on the fibroblasts [32,33], fibrocytes [34], and mast cells [33]. ...
Background . Pretibial myxedema (PTM) is a rare dermopathy. The morphologic features and mechanism of its evolving process are not reported in large case series. Methods . 216 cases with PTM were retrospectively reviewed to analyze demographics, history, lesional morphology and its evolving process, histopathology and immunohistochemistry, serum TRAb levels, treatment, and outcome. Results . First appearing lesions evolved into 6 variants that were correlated with serum TRAb levels. Subvariants were caused by different kinds and frequencies of local trauma. The evolving process could be classified into 4 stages that were correlated with serum TRAb levels and perivascular infiltration of CD8+ and CD4+ lymphocytes. Serum TRAb levels at remission and in nonrecurred cases became lower than those before therapy and in recurred cases, respectively, but increased when PTM relapsed. TRAb level in nodule variant went down invariably with the extension of course and its autoimmune activity had a trend to stop but in other 5 variants TRAb levels fluctuated. Their autoimmune activities had no trends to stop and clinically worsen through intermittent repeats of active and stable stages. Conclusions . In the chronic course of PTM, nodule variant is self-limited and other 5 variants are not self-limited. PTM needed early treatment to avoid severe variants.
... The histological study with alcian blue and Periodic Acid Schiff (PAS) staining presented mucin deposits mostly in the upper and middle dermis layers, causing the separation of the collagen fibers [1]. The biochemical study shows that the main component of mucin is hyaluronic acid [2][3][4][5]. Recent introducing of biological agents into dermatological therapy might be associated with different side effects including skin disorders. ...
... The presented case describes extremely rare coexistence of generalized psoriasis, hy- pothyroidism, and focal skin mucinosis. It should be emphasized that a biological therapy could have an impact on the formation of mucin deposits [5]. Skin mucinoses not associated with thyroid diseases are categorized into a separate group. ...
Skin mucinosis is a rare skin disease which clinically manifests as firm papules and waxy nodules. We report a case of a 66-year-old female psoriatic patient who developed skin mucinosis during biological therapy. Because of a previous lack of response to the local and conventional systemic treatment of psoriasis, the patient received biological therapy (infliximab from June 2008 to May 2009 - initial clinical improvement and loss of treatment effectiveness in the 36(th) week of the therapy; adalimumab from June 2009 to January 2010 - lack effectiveness; ustekinumab from March 2012 to the present). Throughout 2 months we observed a manifestation of the skin mucinosis as well-demarcated, yellow and brown, papulo-nodular lesions of 5-10 mm in diameter, localized on the back. Histopathological examination with alcian blue staining demonstrated mucin deposits in the dermis. On the basis of clinical and histopathological findings, the diagnosis of cutaneous focal mucinosis was established. We present the case because of the extremely rare occurrence of the disease. Scarce literature and data suggest that there is an association between focal mucinosis and thyroid dysfunction, as well as possible adverse effects of biological therapy with TNF-α antagonists.
... Similarly to what occurs with GO, this rare manifestation is associated with high titers of TSHRAbs, and characterized by a large amount of glycosaminoglycans dispersed in the reticular portion of the dermis. TSH-R immunoreactivity has been documented in the pretibium of patients with Graves' dermatopathy (91). ...
The thyroid-stimulating hormone receptor (TSH-R) is predominantly expressed in the basolateral membrane of thyrocytes, where it stimulates almost every aspect of their metabolism. Several extrathyroidal locations of the receptor have been found including: the pituitary, the hypothalamus, and other areas of the central nervous system; the periorbital tissue; the skin; the kidney; the adrenal; the liver; the immune system cells; blood cells and vascular tissues; the adipose tissue; the cardiac and skeletal muscles, and the bone. Although the functionality of the receptor has been demonstrated in most of these tissues, its physiological importance is still a matter of debate. A contribution to several pathological processes is evident in some cases, as is the case of Grave’s disease in its multiple presentations. Conversely, in the context of other thyroid abnormalities, the contribution of the TSH-R and its ligand is still a matter of debate. This article reviews the several different sites of expression of the TSH-R and its potential role in both physiological and pathological processes.
... [12] All patients with active thyroid dermopathy have positive levels of thyroid-stimulating immunoglobulin and laboratory evidence of thyroid autoimmunity, including antibodies against the TSHR (TRAb). [13,14] TRAb has been measured by different assay methods with various names. TBII and TSAb have been measured as TRAb to diagnose Graves' disease. ...
Pretibial myxedema (PTM) is an infiltrative dermopathy seen in Graves' disease. It is also infrequently associated with hypothyroidism. Here, we describe a rare case of PTM with hypothyroidism in which thyroid-stimulating hormone receptor antibodies were found. An 82-year-old female presented with a 1-year history of a large pruritic plaque which was present over both her legs and feet. Histopathology of a skin biopsy showed markedly increased dermal mucin. These changes were suggestive of PTM. This case provides evidence that an autoimmune mechanism could play a central pathogenetic role in such cutaneous manifestations.
... Orbital adipose tissue of patients with GO (including euthyroid patients) is characterized by greater expression of TSHR than control tissues from people without GD [65,66]. An elevated level of TSHR has been also noticed in pretibial connective tissue from patients with thyroid-associated dermopathy [67]. Some studies have shown that the level of antibodies against TSHR (TRAb) correlates with the clinical activity and severity of GO [68,69]. ...
The body’s autoimmune process is involved in the development of Graves’ disease (GD), which is manifested by an overactive thyroid gland. In some patients, autoreactive inflammatory reactions contribute to the development of symptoms such as thyroid ophthalmopathy, and the subsequent signs and symptoms are derived from the expansion of orbital adipose tissue and edema of extraocular muscles within the orbit. The autoimmune process, production of antibodies against self-antigens such as TSH receptor (TSHR) and IGF-1 receptor (IGF-1R), inflammatory infiltration, and accumulation of glycosaminoglycans (GAG) lead to edematous-infiltrative changes in periocular tissues. As a consequence, edema exophthalmos develops. Orbital fibroblasts seem to play a crucial role in orbital inflammation, tissue expansion, remodeling, and fibrosis because of their proliferative activity as well as their capacity to differentiate into adipocytes and myofibroblasts and production of GAG. In this paper, based on the available medical literature, the immunological mechanism of GO pathogenesis has been summarized. Particular attention was paid to the role of orbital fibroblasts and putative autoantigens. A deeper understanding of the pathomechanism of the disease and the involvement of immunological processes may give rise to the introduction of new, effective, and safe methods of treatment or monitoring of the disease activity.
... Pretibial fibroblasts, like the orbital ones, have been shown to express the TSHR, and the interaction of these fibroblasts with TSHR-sensitized T cells and/or TRAb leads to the inflammatory and infiltrative cascade of both GO and PTM. 55,56 The pathogenesis of PTM is characterized by fibroblast proliferation and glycosaminoglycan accumulation causing nonpitting edema, which leads to compression of dermal lymphatics and can progress to significant lymphedema. 57 This underlying autoimmune response in addition to the dependent nature of legs usually causes dermopathy to affect the pretibial areas. ...
Purpose:
Thyroid autoimmunity affects approximately 5% of the population, and its investigation relies heavily on the use of autoantibodies. Thyroid stimulating hormone receptor (TSHR) autoantibodies (TRAb) play a central role in the evaluation of Graves disease (GD), Graves ophthalmopathy (GO) and pretibial myxedema (PTM). However, there is still controversy regarding overall TRAb assay diagnostic accuracy and their prognostic utility.
Methods:
We reviewed and analyzed the literature reporting TRAb assays and their clinical utility.
Results:
Current assays measure the overall TRAb titer in a competitive manner (TSH binding inhibiting immunoglobulin assay) or biologic activity of the stimulating TSHR autoantibodies (thyroid stimulating immunoglobulin assay). Both types of assays have improved over time with advances in sensitivity and specificity. TRAb are particularly relevant in hyperthyroidism cases where use of iodinated contrast is not an option (e.g., pregnancy or recent use of iodinated contrast) or in cases of euthyroid eye disease, suspicious for GO. Third generation TRAb assays are useful for therapy selection in GD, prognostic predictions in GO and risk prediction for fetal and neonatal thyrotoxicosis.
Discussion:
Given the pathogenic role of TRAb, we expect that the future will bring useful evidence regarding their predictive role with respect to efficacy of therapeutic modalities for GO and PTM. We also hope to better understand the role of blocking and neutral antibodies against TSHR, and harness that ability for modulation of thyroid function or therapy of differentiated thyroid carcinoma managed with TSH suppression.
Conclusions:
Thyroid autoimmune diseases have seen tremendous gains in understanding their pathophysiology, largely antibody mediated. Better TRAb testing is becoming a springboard for providing individualized patient care.
... This points at a direct link between TSHR expression levels in orbital fibroblasts and the pathogenicity of the TSHR stimulatory autoantibodies in GO. TSHR expression has also been found in pretibial fibroblasts from GD patients where it may thus contribute to pretibial myxedema, another (less frequent) extra-thyroidal complication of GD that is also characterized by increased hyaluronan deposition (Smith et al., 1989a;Wu et al., 1996;Stadlmayr et al., 1997;Daumerie et al., 2002;Bahn, 2010). ...
Graves' ophthalmopathy (GO) is an extra-thyroidal complication of Graves' disease (GD; Graves' hyperthyroidism) characterized by orbital tissue inflammation, expansion, remodeling and fibrosis. Although the initiating trigger of GO is still indistinct, excessive orbital fibroblast activity is at the heart of its pathogenesis. Orbital fibroblasts are activated by cellular interactions with immune cells and the soluble factors they secrete. Orbital fibroblasts, especially from GO patients, express the thyrotropin receptor (TSH-receptor; TSHR), and activation of the orbital fibroblast population by stimulatory autoantibodies directed against the TSHR may provide an important link between GD and GO. Furthermore, stimulatory autoantibodies directed against the insulin-like growth factor-1 receptor have been proposed to contribute to orbital fibroblast activation in GO. Activated orbital fibroblasts produce inflammatory mediators thereby contributing to the orbital inflammatory process in GO. Moreover, orbital fibroblasts exhibit robust proliferative activity and extracellular matrix (especially hyaluronan) synthesizing capacity and can differentiate into adipocytes and myofibroblasts with disease progression, thereby contributing to tissue expansion/remodeling and fibrosis in GO. Orbital fibroblasts, especially those from GO patients, exhibit a hyper-responsive phenotype when compared to fibroblasts from other anatomical regions, which may further contribute to GO pathogenesis. Fibrocytes have been identified as additional source of orbital fibroblasts in GO, where they may contribute to orbital tissue inflammation, adipogenesis and remodeling/fibrosis. This review addresses our current view on the role that orbital fibroblasts fulfill in GO pathogenesis and both established as well as less established not fully crystallized concepts that need future studies will be discussed.
... More and more evidences keep accumulating in the autoimmune pathogenesis of PTM. Antigen-specific T lymphocytes infiltrating the pretibial lesions are of primary immune response [17], high serum levels of TRAbs are found in all PTM patients [18], TSH receptors exist on the dermal fibroblasts of pretibial skin [19], and IgG, IgA and C3 deposit in the pretibial lesions of PTM [20]. Therefore, PTM is considered to be a local autoimmune entity associated with autoimmune thyroid diseases [21,22], in which cell-mediated and humoral immunity (TRAb) plays a role in the pathogenesis [23]. ...
... Apart from thyrocytes, the expression and the possible role of the TSHR had been extensively studied in several different cellular subsets in the last years. A number of tissues [22], notably skin [23] and aorta [24], exhibit TSH receptors. Thus, TSH could have direct receptor-mediated effects activating fibroblasts in the dermis and other tissues. ...
Systemic sclerosis (SSc) is a connective tissue disease, characterized by cutaneous and multi-organ fibrosis, and vascular abnormalities. Skin thickening is a characteristic feature of SSc and resembles myxedematous skin. Our aim was to correlate the degree of skin involvement in SSc patients with serum TSH levels, since TSH receptors are widely expressed in human tissues, including the skin. In this cross-sectional study, we enrolled 70 SSc patients, all females with a mean age of 47 ± 11 year. Thirty-five age- and sex-matched HT patients were recruited, as controls. Subjects under L-thyroxine therapy and/or with positive anti-TSH receptor antibodies were excluded. In all subjects, we measured serum TSH, FT4, and free tri-iodothyronine (FT3) levels. Skin thickness was evaluated using the modified Rodnan total skin score (mRSS). mRSS averaged 14 ± 9 for SSc and 4 ± 6 for HT patients. TSH levels positively correlated with skin scores in both SSc and HT patients groups. In SSc patients, FT3 and FT4 showed an inverse correlation with mRSS, while in HT only FT4 levels showed this inverse significance. When divided by cutaneous extent, SSc patients with diffuse disease form had higher TSH serum levels compared to those with the limited form; additionally, the correlations between TSH, FT4, and mRSS reached statistical significance. Our preliminary data clearly indicate that serum TSH is higher in SSc patients with more severe skin disease, and significantly correlate with the mRSS. Therefore, TSH could play a role in the development of cutaneous changes in SSc patients.
... There is evidence from another extra-thyroidal manifestation, pretibial myxoedema (PM) to support both points of view. Immunoglobulins from GD patients stimulate the production of intercellular adhesion molecule-1 from GD but not normal fibroblasts, highlighting a difference in these two populations of cells (Heufelder & Bahn 1992) and TSHR immunoreactivity has been demonstrated in PM and normal skin biopsies (Rapoport et al. 2000, Daumerie et al. 2002. ...
The thyrotrophin receptor (TSHR) provides an autoantigenic link between the thyroid and orbit in Graves’ (GD) and thyroid eye diseases (TED). We measured TSHR transcripts in different fat depots to determine whether TSHR expression levels are influenced by the autoimmune/inflammatory process and/or thyroid hormone status, using quantitative real-time PCR. Nine intact or fractionated adipose samples, from patients with GD and/or TED, were analysed ex vivo. Eight expressed the TSHR, at levels approaching the thyroid, and one was at the limit of detection. Thirteen/fifteen orbital and abdominal fat samples from patients free of GD and TED, measured ex vivo, were negative for TSHR transcripts and two were at the limit of detection. All preadipocyte samples induced to differentiate in vitro expressed the TSHR. To investigate the influence of thyroid hormone status on adipose TSHR expression, we induced hyper- and hypothyroidism in BALBc mice by administering tri-iodothyronine and propylthiouracil respectively. In euthyroid animals, whole fat samples were at the limit of detection and were not altered by thyroid hormone status. The results show that adipose TSHR expression ex vivo indicates adipogenesis in progress in vivo and is associated with the autoimmune/inflammatory process in GD and TED but is not restricted to the orbit or influenced by thyroid hormone status.
... Experimental outcomes prove that the TSH receptor transcript is present in the human heart (Koshiyama et al., 1996). TSH receptor transcripts and receptor immunoreactivity were found in fibroblasts of different origins (Daumiere et al., 2002;Feliciello et al., 1993). Collagen accumulation in the heart is responsible for the increased stiffness of the heart wall and may contribute to diastolic heart failure development. ...
... These activated pretibial fibroblasts react with T lymphocytes on thyrotropin receptors and release excess glycosaminoglycans. [4] A subgroup of orbital fibroblasts can differentiate into mature adipocytes with increased expression ...
Graves' disease (GD) is one of the urgent problems of modern endocrinology, characterized by a high frequency, polysystemic damage to the body, a steadily progressive course, diagnostic difficulties, a high degree of disability and often resistance to therapy. The manifestations of the disease include: thyrotoxicosis syndrome with impaired lipid and carbohydrate metabolism, and activation of multiple organ pathology in the form of thyroid eye disease (TED), pretibial myxedema, cardiovascular insufficiency, acropathy, lesions of the nervous, osteoarticular system, and other lesions. The development of multiple organ pathology can have a different sequence, different time intervals and different degrees of severity. Any developments in the direction of clarifying the etiopathogenetic, clinical diagnostic and treatment-rehabilitation measures are of undoubted significance. We present a clinical case of GD, TED and pretibial myxedema, in which an integrated approach was tested in the tactics of treating pretibial myxedema (a combination of pulse therapy with prednisolone and FREMS-therapy), as a result of which positive results were obtained within a short time.
Thyroid eye disease (TED) is the most common extra-thyroidal manifestation of Graves’ disease. TED manifests as photophobia, proptosis, erythema, or conjunctival injection. Other signs suggestive of TED include lid lag, globe lag, lid retraction, and even, in some cases, evidence of optic neuropathy. TED up until recently had very few effective medical therapies. Teprotumumab, a monoclonal antibody that targets the IGF-1 receptor, was recently approved for the treatment of TED.
This work was aimed to study levels of thyroid hormone receptors in human dermal fibroblasts from the development to deep aging. Skin specimens from human fetuses died antenatally from 20 to 40 weeks of pregnancy, humans died from different causes from birth to 85 years of life were used for the study. Total number of fibroblasts, percent of proliferating cells nuclear antigen (PCNA) positive dermal fibroblasts, expression of thyroid hormone receptors-α and -β in dermal fibroblasts were examined. PCNA and thyroid hormone receptors were viewed immunohistochemically. A total number of fibroblasts in dermis were counting in sections stained with haematoxylin and eosin. Results showed that maximal levels of thyroid hormone receptors-α and -β were observed from 20 to 40 weeks of pregnancy. The levels of thyroid hormone receptors-α and -β were decreased from birth to 40 years of life. From 41 to 85 years, the levels of thyroid hormone receptors were approximately the same. A total number and percent of PCNA positive fibroblasts in dermis decreased with progression of age. Most sufficient age-dependent reduction in a total and PCNA positive number of dermal fibroblast was observed from antenatal until 40 years of life. Correlation analysis and one-way ANOVA showed that age-dependent decrease in the number of fibroblasts and retardation of their proliferation in human dermis is significantly associated with age-related decrease in the level of thyroid hormone receptors-α and -β in dermal fibroblasts. Results allow to suggest that thyroid hormone receptors are involved in age-dependent decrease in the number and proliferation of fibroblasts in human dermis.
Pretibial myxedema is an infrequent dermatopathy, that occurs in some patients with Graves' disease. It rarely coexist with thyroid ophtalmopathy or acropachy, the other manifestations of this autoimmunological disease. We present a case of a 76-year-old woman with Graves' disease who was first treated with thyreostatics and then, because of the recurrent thyreotoxicosis she was given a radical therapy with radioactive iodine. Two years later a nonpitting edema accompanied by typical skin color changes and hipertrichosis localized on her feet and in the pretibial area appeared. Our patient didn't realize that it could be a new manifestation of Graves' disease. Many dermatological diseases were considered in the differential diagnosis. Because of the dermatological and ophtalmological complaints both local and systemic steroids were given by the endocrinologist and a complete remission was achieved. The dose of steroids was gradually reduced. About three weeks after the therapy was finished, the symptoms' recurrence was observed. The therapy with steroids was repeated and the second remission was achieved. The patient stays under the clinical control. We present this case because of the rare incidence of the pretibial myxedema, the diagnostic problems and treatment difficulties that it caused to many specialists.
Cloning of the TSH receptor has led to marked progress in the understanding of the pathogenesis of hyperthyroidism. Genetic studies in familial cases of Graves disease have allowed to dismiss the TSH receptor as a candidate gene. Loci harbouring genes probably involved in the occurrence of Graves' disease have been described. Purification of native TSH receptor has allowed to study directly and to characterize the autoantibodies directed against this antigen. In cases of non immune hyperthyroidism the implication of activating mutations of the TSH receptor and of the a subunit of Gs has been described.
The symptoms of hiper- and hipothyroidism are nonspecific and affect several internal organs as well as the skin. The aim of this study was to present all skin manifestations in thyroid dysfunction and thyroid autoimmune diseases, as well as symptoms which coexist with thyroid diseases. Skin, hair and nail changes in thyroid disease may be the first, or the main, reason for a patient to consult the physician. Understanding these symptoms is important in order to diagnose and treat the thyroid disease. The problem is essential because of the high incidence of thyroid diseases and correlated with them skin, hair and nail changes.
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.
Analysis of the morphological status, oxidative stress (OS) and antioxidant defenses in the orbital muscular cells and adipocytes in GO patients as compared to controls.
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 (peroxiredoxins 5 and catalase) against the OS, which are also upregulated in thyrocytes in GD. The expression of adiponectin (ApN) and PPARγ is also increased in GO muscular cells and adipocytes. OS and antioxidant proteins expression are correlated to the level of blood anti-TSH receptor antibodies (TSHR-Ab).
Even when TSHR-Ab level is normalized, OS and antioxidant protein expression is high in EOM muscular cells and adipocytes in GO, as compared to 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.
As the largest organ in the body, the skin may reveal the first manifestations of internal disease. The astute clinician can often use dermatologic findings to diagnose an underlying systemic disease. This chapter outlines some of the most important skin manifestations of internal disease. Common yet clinically important systemic diseases will be reviewed, and their most notable skin findings will be delineated.
Ocena stężenia glikozoaminoglikanów (GAG) siarczanowanych oraz kwasu hialuronowego (HA) w surowicy krwi osób z chorobą Gravesa i Basedowa, zarówno przed leczeniem, jak i po jego zakończeniu i uzyskaniu eutyreozy, stanowiła cel niniejszej pracy. Materiałem do badań była surowica krwi pozyskana od 17 pacjentów ze świeżo rozpoznaną chorobą Gravesa i Basedowa oraz tych samych osób po przywróceniu u nich stanu eutyreozy. U pacjentów z chorobą Gravesa i Basedowa, których surowicę krwi wykorzystano do badań stanowiących cel niniej-szej pracy, nie wykazano powikłań o charakterze oftalmopatii lub/i obrzęku przedgoleniowego. Z surowicy krwi wyizolowano glikozoami-noglikany stosując wieloetapową ekstrakcję i oczyszczenie tych związków, obejmujących hydrolizę papainą, β-eliminację oraz sprzęganie z chlorkiem cetylpirydyniowym. Miarą wyizolowanych GAG było stężenie kwasów heksuronowych. Zawartość HA w próbkach wyizolowanych GAG oznaczono metodą ELISA. Stwierdzono, że w surowicy krwi osób z nieleczoną chorobą Gravesa i Basedowa dochodzi do znacznego wzrostu stężenia zarówno GAG siarczanowanych, jak i stężenia HA. Uzyskanie stanu eutyreozy prowadziło do obniżenia stężenia GAG siarczanowanych, choć nie do normalizacji omawianych wartości. Natomiast stężenie HA osiągnęło wartość zbliżoną do stwierdzanej u osób zdrowych. Niewykluczone, że zmiany metabolizmu GAG siarczanowanych i HA w przebiegu choroby Gravesa i Basedowa mogą prowadzić do ogólnoustrojowych zmian właściwości macierzy pozakomórkowej. [Wiad Lek 2006; 59(1–2): 66–71] Słowa kluczowe: glikozoaminoglikany, kwas hialuronowy, choroba Gravesa i Basedowa. Glikozoaminoglikany (GAG) to liniowe, nierozgałę-zione heteropolisacharydy, zbudowane z powtarzających się reszt N-acetylowanej lub N-siarczanowanej heksozo-aminy oraz reszt kwasu heksuronowego albo galaktozy [1,2]. Wymienione reszty węglowodanowe w większo-ści GAG są siarczanowane [3,4]. Kwas hialuronowy (HA) – jako jedyny GAG – nie ulega siarczanowaniu oraz nie tworzy kowalencyjnych połączeń z białkami, co w przypadku innych GAG prowadzi do utworzenia proteoglikanów (PG) [3,4,5,6,7]. Wszystkie glikozoami-noglikany występują powszechnie w przestrzeni pozako-mórkowej, spełniając wiele funkcji [1,3,7]. Uczestniczą w procesach różnicowania, adhezji i migracji komórek, czy też mineralizacji kości [1,7]. Wpływają ponadto na spoistość, elastyczność i stopień uwodnienia macierzy pozakomórkowej oraz regulują jej przepuszczalność dla obdarzonych ładunkiem cząsteczek [3,5,8]. Zaburzenia przemian glikozoaminoglikanów, prze-jawiające się gromadzeniem tych związków w ma-cierzy pozakomórkowej tkanek przyocznych i tkanek okolic przedgoleniowych, stanowią jedno z ogniw łańcucha zmian patogenetycznych, prowadzących do wystąpienia pozatarczycowych objawów choroby Gravesa i Basedowa, tj. oftalmopatii i obrzęku przed-goleniowego [9]. Nie wiadomo jednak, czy nadmiar hormonów tarczycy w ustroju osób z nieleczoną cho-robą Gravesa i Basedowa, niepowikłaną wystąpieniem zmian ocznych i/lub skórnych, wpływa na metabolizm GAG. Przemiany GAG siarczanowanych podlegają odmiennej regulacji niż w przypadku nieulegającego procesom siarczanowania HA [10]. Zróżnicowana podatność obu rodzajów GAG na działanie czynników regulacyjnych sugeruje możliwość ich odmiennej roli w patogenezie choroby Gravesa i Basedowa. Z uwagi na fakt, że stężenie GAG we krwi jest odzwierciedleniem ich metabolizmu w tkankach, za cel pracy przyjęto ocenę ich stężenia w surowicy krwi chorych ze świeżo rozpoznaną, dotychczas nieleczoną chorobą Gravesa i Basedowa, niepowikłaną oftalmopatią i/lub obrzękiem przedgoleniowym, oraz ocenę stężenia wymienionych związków w surowicy krwi tych samych osób po zakoń-czeniu leczenia i uzyskaniu stanu eutyreozy.
About 5% of patients with Graves' disease (GD) develop Graves' orbitopathy (GO) of sufficient severity to require treatment. GD is an autoimmune condition caused by thyroid stimulating antibodies (TSAB) mimicking the action of TSH, although the mechanisms leading to loss of tolerance to the TSHR remain unknown. In GO, tissue remodeling increases the volume of the orbital contents by several mechanisms including adipogenesis and overproduction of glycosaminoglycans (GAGs). The increased volume produces proptosis, chemosis and increased intraocular pressure. GO is also an autoimmune disease and the timing of its onset (relative to GD) suggests a thyroid/orbit shared antigen. Data in favour of the antigen being the TSHR include demonstration of its increased expression during adipogenesis and the fact that the most severe GO occurs in GD patients having the highest TSAB titres. Evidence against its role are patients with euthyroid GO (devoid of TSAB) and its widespread expression. However, recent reports demonstrate a direct role for TSHR autoantibodies in GAG production, but it is likely that other antigens, such as IGF-1R, may also contribute to pathogenesis. In vitro models have demonstrated the heterogeneity of orbital fibroblasts, some destined for adipogenesis and/or secretion of GAGs in response to stimulation by inflammatory cytokines or patient immunoglobulins. GO may be exacerbated by e.g. PPARγ agonists, but PPARγ antagonists (inhibit adipogenesis) may provide novel treatment options. Of interest, B cell depletion, which does not consistently reduce TSAB levels, also shows some promise but further adds to the puzzle of the relevance of the TSHR.
Background
Localized myxoedema is a rare dermopathy in patients with Graves’ disease. The pretibial area is the most commonly affected region but herein we present a case of myxoedema of the big toe.
Patients and methods
A 44-year-old male with Graves’ disease ongoing for seven years presented bilateral ophthalmopathy and myxoedema of the big toes. The myxoedema was treated successfully with intralesional steroids.
Discussion
The physiopathology of myxoedema involves fibroblast activation and glycosaminoglycan production. This activation could result from stimulation of TSH receptors at their surface by TSH receptor antibodies (TRAK) or from an inflammatory process. The pretibial topography may be related to the high frequency in this area of microtrauma, with modulation of the cytokine microenvironment.
Conclusion
The atypical localization seems to correlate with a Koebner phenomenon. Treatment of Graves’ disease is generally insufficient to resolve the cutaneous problems. Topical corticosteroid therapy generally results in rapid improvement of recent lesions.
Graves’ ophthalmopathy [thyroid-associated ophthalmopathy (TAO)] and dermopathy [thyroid-associated dermopathy (TAD)] are
extrathyroidal manifestations of Graves’ disease, which should be viewed as a multisystem autoimmune disease involving thyrocytes
but also orbital and pretibial fibroblasts. Smoking is a risk factor for TAO, and cessation of smoking is useful in the primary,
secondary and tertiary prevention of TAO. The immunopathogenesis of TAO and TAD looks very similar. Fibroblasts expressing
functional thyroid-stimulating hormone (TSH) receptors have been identified as the target cells of the autoimmune attack.
T cells sensitized to thyroid antigens (or TSH receptor stimulating antibodies, TSAb, in later stages) may recognize shared
antigens on fibroblasts, inducing release of cytokines. This results in the production of hydrophylic glycosaminoglycans,
causing tissue swelling. Recent findings point to the insulin-like growth factor (IGF)-1 receptor on fibroblasts as another
likely autoantigen. TAO appears to be primarily a Th1-cell-mediated disease. Intravenous methylprednisolone pulses are now
recommended as the treatment of choice in severe active TAO and topical corticosteroids under occlusive dressings for TAD.
Rehabilitative surgery for TAO should wait until the disease has become inactive. Promising new but still experimental treatment
modalities involve monoclonal antibodies against particular cytokines or T-cell surface molecules.
Introduction:
Dermal mucinosis can be associated with numerous pathologies, in particular involving the thyroid, but has never been described in the case of a medullar cancer of the thyroid (MCT).
Case-report:
A 69-year-old man consulted for a facial erythrosis, which had been developing for a few weeks without any identified triggering factor. The skin biopsy showed dermal mucinosis and tests revealed a sporadic medullar cancer of the thyroid with secondary bone, ganglion and medullar localizations.
Discussion:
The association between medullar cancer of the thyroid and dermal mucinosis has never been described. Several hypotheses may explain this: the thyroid pathology itself, whatever its nature, the capacity of the MCT to synthesize mucin and the medullar metastatic overgrowth.
Localized myxoedema is a rare dermopathy in patients with Graves' disease. The pretibial area is the most commonly affected region but herein we present a case of myxoedema of the big toe.
A 44-year-old male with Graves' disease ongoing for seven years presented bilateral ophthalmopathy and myxoedema of the big toes. The myxoedema was treated successfully with intralesional steroids.
The physiopathology of myxoedema involves fibroblast activation and glycosaminoglycan production. This activation could result from stimulation of TSH receptors at their surface by TSH receptor antibodies (TRAK) or from an inflammatory process. The pretibial topography may be related to the high frequency in this area of microtrauma, with modulation of the cytokine microenvironment.
The atypical localization seems to correlate with a Koebner phenomenon. Treatment of Graves' disease is generally insufficient to resolve the cutaneous problems. Topical corticosteroid therapy generally results in rapid improvement of recent lesions.
Purpose of review: The thyroid-stimulating hormone, or thyrotropin, receptor (TSHr) is the autoantigen against which the autoimmune response is directed in Graves hyperthyroidism. The close clinical associations between hyperthyroidism, Graves ophthalmopathy (GO), and pretibial dermopathy (PTD) led to the hypothesis that these conditions represent different manifestations of the same autoimmune disease. This paper reviews recent literature concerning the potential role of TSHr as an autoantigen in the pathogenesis of the extrathyroidal manifestations of Graves disease.
Recent findings: Recent studies from several laboratories suggested that low-abundance TSHr messenger RNA and protein are present in normal connective and adipose tissues from many anatomic sites. In addition, increased expression of this receptor has been demonstrated in orbital and dermal tissues from patients with GO and PTD.
Summary: In normal individuals, low-abundance TSHr expression in connective tissues throughout the body may have little physiologic relevance. However, in the setting of Graves disease with circulating antibodies and T cells directed against this antigen, a generalized, subclinical, connective tissue inflammation may develop. On this background, local environmental factors affecting the orbit and pretibial skin may contribute to the development of clinical disease at these sites. Alternately, locally enhanced expression of TSHr at the sites of clinical disease may not be directly involved in pathogenesis but could be secondary to the ongoing disease process and important in disease progression.
Thyroid dermopathy that occurs in 4–13 % of patients with Graves’ ophthalmopathy is an extrathyroidal manifestation of Graves’ disease. Thyroid acropachy commonly presents with clubbing of digits and occurs in 20 % of patients with dermopathy. Basic pathogenesis of dermopathy is similar to ophthalmopathy. Presence of TSH receptor in the fibroblasts and its interaction with TSH receptor antibodies and stimulation of fibroblasts resulting in production of glycosaminoglycans is the most likely immune process. Localization of thyroid dermopathy to lower extremity is explained by mechanical factors such as dependency of the lower extremity.
Measures for prevention and treatment of dermopathy include optimal and rapid normalization of thyroid function and early local corticosteroid therapy for existing pretibial myxedema. Systemic therapies used in ophthalmopathy can be tried in refractory cases not responding to local corticosteroid therapy. In future any systemic therapy proven to be beneficial for ophthalmopathy can be used empirically for refractory cases of dermopathy.
For thyroid acropachy no specific therapy has been reported and management should be preventive and local therapy for associated dermopathy of hands and feet. In severe cases of acropachy with painful periosteal reaction, pain management will be needed.
Introduction. All symptoms and most objectively verified abnormalities of fibromyalgia are common among patients with hypothyroidism or partial peripheral thyroid hormone resistance. In treatment trials, thyroid hormone therapy has reduced or eliminated fibromyalgia symptoms, and a long-term follow-up study showed that improvement with thyroid hormone therapy lasted 1-to-5 years. In a previous study by the authors, solicited female fibromyalgia patients had significantly lower resting metabolic rates and basal body temperatures than matched healthy controls. In this study, the resting metabolic rates and body temperatures of fibromyalgia patients previously evaluated at a specialty metabolic clinic were compared with healthy controls to whom they were matched. Methods. Fifteen female fibromyalgia patients and 15 healthy females served as study subjects. Patients were clinical cases selected to match controls by sex, age, weight, and activity level. Resting metabolic rate (RMR) was measured by indirect calorimetry (MedGem), basal body temperature with digital thermometers, and body composition by bioelec-® trical impedance. The mean measured resting metabolic rate (mRMR) was compared to percentages of the mean predicted RMR (pRMR) by two methods: fat-free weight (Sterling-Passmore equation: SP) and sex, age, height, and weight (Harris-Benedict and Mifflin-St. Joer equations: HB and MSt.J). Measurements were taken during the follicular phase of subjects' menstrual cycles. Results. Patients had a lower mean mRMR (939.70 ± 216.04 kcal/d vs 1293.40 ± 166.34 kcal/d, p = 0.00001) and lower mRMRs as percentages of pRMRs (SP: -26.91 ± 13.36% vs -6.826 ± 12.55%, p < 0.0001. HB: -32.45 ± 13.48% vs -9.13 ± 9.51%, p = 0.0001; MSt.J: -27.96 ± 14.53% vs -5.089 ± 11.30%, p = 0.0002). Age and fat-free weight accounted for 62% of variability in controls'mRMRs. Fat-free weight, water as a percentage of body weight, and fibro-myalgia symptom intensity accounted for 83% of the variability of patients' mRMRs. Patients' mean basal body tem-perature was significantly lower than that of controls (96.38 ± 0.98° F vs 97.54 ± 0.59° F, p = 0.001). Patients' serum free 3 T level was significantly lower than that of controls (3.18 ± 0.559 vs 3.75 ± 0.717 pg/mL, p = 0.023). Conclusions. The patient group had a lower mean mRMR and lower mRMR as percentages of pRMRs. Patients also had a significantly lower mean basal body temperature. Neither calorie restriction nor low fat-free weight accounted for patients' lower RMRs. As in the previous study, fibromyalgia patients' normal fat-free weight argues against low physical 43 activity with poor physical fitness as the mechanism of their low RMRs. Free T , free T , and TSH levels did not correlate with fibromyalgia measures or RMRs in either patient or control group. The lack of correlation does not rule out in-adequate thyroid hormone regulation as the mechanism of the low RMRs because studies have not shown that these laboratory values reliably predict RMR values. 43 KEY WORDS. Resting metabolic rate, fibromyalgia, basal body temperature, body composition, TSH, free T , free T .
Pretibial myxedema (thyroid dermopathy) is the sine qua non of the dermatologic manifestations of thyroid disease. Although
any medical student can reflexively state that pretibial myxedema is a hallmark of Graves disease, how many clinicians realize
that the term is a misnomer? That thyroid dermopathy is not necessarily limited to the pretibial region and is not exclusively
seen in patients with Graves disease are just two facts frequently misconceived about this condition. The reality is that
much has been learned about the immunologic pathogenesis of thyroid der- mopathy, a condition that results from the accumulation
of the glycosaminoglycans, hyaluronic acid, and chondroitin sulfate in the dermis. A precise understanding of its pathogenesis,
however, remains to be determined. This chapter surveys the clinical, biological, and therapeutic landscape of thyroid dermopathy.
By understanding its natural history, eliminating or reducing predisposing factors such as smoking and obesity, appreciating
the complexities of the immunologic aberrations leading to mucin deposition, and having a logical approach to therapy, clinicians
should be able to at least ameliorate this chronic, occasionally severe, recalcitrant disorder.
The immunopathogenesis of Graves' ophthalmopathy (GO) is still incompletely understood. Attention has shifted from the TSH receptor (TSHR) to the IGF-I receptor (IGF-1R) as a major autoantigen. This review on the pathophysiology of GO focused on orbital fibroblasts and the question whether autoimmunity against TSHR or IGF-1R is primarily involved.
Relevant papers on GO were identified by a search on PubMed and scrutiny of their reference lists. In addition, abstracts presented on GO at the 14th International Thyroid Congress in 2010 in Paris, France, were read.
Orbital fibroblasts (OF) are recognized as the prime target cells of the autoimmune attack in GO. In early stages OF are undifferentiated with low TSHR expression and are stimulated to produce hyaluronan by cytokines (released by activated infiltrating T cells) and not by Graves' IgG. OF lacking the surface glycoprotein Thy-1 (not present in the muscle compartment) may differentiate into adipocytes, associated with increased TSHR expression. Graves IgG stimulate hyaluronan in differentiated OF mostly via non-cAMP signaling pathways for growth, which can also be activated via TSHR. The existence of IGF-1R stimulating antibodies in serum remains dubious. Autoimmunity against IGF-1R is also observed in rheumatoid arthritis and is not specific for Graves' disease. Expression of IGF-1R on T and B lymphocytes may contribute to autoimmunity against fibroblasts. Conclusion: Autoimmunity against TSHR is most likely initiating the immune response in GO. Autoimmunity against IGF-1R is not specific for Graves' DISEASE but may contribute to ongoing immune reactions.
Pretibial myxedema (PM) is an uncommon and characteristic manifestation of Graves' disease (GD), with local autoimmune reaction in cutaneous tissue. The treatment of PM is a clinical challenge. We herein report a patient with PM who achieved complete remission by multipoint subcutaneous injection of long-acting glucocorticid.
A 38-year-old man presented with an 18-month history of GD and a 1-year history of PM. Physical examination revealed mildly prominent eyes, diffuse enlargement of the thyroid gland, and PM of both lower extremities. The patient was treated with triamcinolone acetonide by multipoint subcutaneous injections in a combined dose of 20 mg in each lower extremity administered every 25-28 days. The injection was started from the borderline of the lesions and normal skin by selecting 4 to 5 points per leg for each course and then moving to other parts in subsequent courses of treatment. The depth of needle insertion was 0.5-1.0 cm. The patient's PM achieved complete remission in both lower extremities after an approximately 6-month period that included seven courses of treatment with a total dosage of 280 mg triamcinolone acetonide.
Our experience with this patient suggests that multipoint subcutaneous injection of long-acting glucocorticid is a safe, effective, and convenient treatment of PM in patients with GD.
Localized pretibial myxedema (PTM) is a sign of Graves' disease. A 53-year-old man with Graves' disease was admitted with the development of PTM following radioisotope (131)I treatment for Graves' hyperthyroidism. TSH receptor antibody (TRAb) titer was also increased after (131)I treatment. TRAb was measured as thyroid stimulating antibody (TSAb) or TSH-binding inhibitory immunoglobulin (TBII). PTM was noted several months after (131)I treatment. The PTM-development seems to be associated with the increased TRAb-activities. The localized pretibial myxedema was effectively treated with topical steroid (triamcinolone acetonide) ointment application with sealing cover (steroid occlusive dressing technique: steroid ODT). We also report our experience of PTM-treatment with steroid ODT in 5 other PTM patients with positive TRAb. PTM was successfully treated with steroid ODT in two patients. In these two patients, the treatment was started within several months of the appearance of PTM. In the other 4 patients, the treatment was started 5-10 years after the appearance of PTM without any beneficial effects. Early detection and early treatment are necessary for the remission of PTM.
Thyroid associated ophthalmopathy (TAO) is generally considered to have an autoimmune pathogenesis but the target antigen has yet to be identified. It is most frequently associated with Graves' disease and there is some logic in assuming that the same antigen, the thyrotropin receptor (TSHR), is the common link. Previous studies, mostly PCR based, aimed at investigating TSHR transcripts in the orbit, have yielded conflicting results, although there is circumstantial evidence for their presence in orbital fat. In this study, we have examined adult human adipose and muscle tissues from various locations, initially by PCR and subsequently by northern blot. We obtained the expected 610bp product in normal intestinal and orbital fat but not skeletal muscle, following two rounds of PCR amplification but only when reverse transcription used a TSHR specific primer. In northern blots, despite loading all of the RNA obtained from total normal orbital fat contents, TSHR transcripts were at the limit of detection and similarly for large samples of intestinal fat. The exception was RNA obtained from TAO orbital fat, in which TSHR transcripts of 4.6 and 1.7kb were clearly visible, as in the thyroid. We conclude that normal adult adipose tissues contain low levels of TSHR transcripts. In TAO, TSHR transcripts are elevated probably due to an increased number of cells, in particular of preadipocytes in orbital adipose tissue.
The generation of Abs recognizing the native structure of the human thyrotropin receptor (hTSHR) has been difficult because there is currently no method allowing the purification of correctly folded Ag in the amounts required by classical immunization protocols. The majority of Abs made against the hTSHR react preferentially with denatured molecules. We report that a humoral response against the native hTSHR, compatible with mAb production, is elicited in mice by immunization with a DNA construct encoding the receptor. BALB/c mice were inoculated in the anterior tibialis muscle with 100 microg of plasmid DNA harboring the hTSHR cDNA. Eleven weeks after the first injection, 10 mice of 14 showed by FACS analysis a strong IgG response against the hTSHR expressed at the surface of Chinese hamster ovary cells. A clear TSH-binding inhibiting Ig and thyrotropin-blocking Ab activity (competition with TSH binding and TSH activity, respectively) was demonstrated in the majority of sera tested. One serum exhibited a clear stimulating activity. Despite the maintenance of normal circulating free T4 levels in all mice, these bioactivities persisted until 18 wk, in which mice were sacrificed, their thyroids were examined histologically, and spleens from two animals were used for mAb production. All mice displayed a severe lymphocytic infiltration of their thyroids, composed mostly of activated B cells. Three mAbs were produced against conformational epitopes of the hTSHR. We conclude that genetic immunization is an efficient method of generating Abs recognizing the native structure of the hTSHR and a new way of inducing thyroiditis in mice murine.
It is acknowledged that the TSH receptor (TSHr) on thyroid follicular cells is the autoantigen involved in the hyperthyroidism of Graves' disease. However, whether this receptor is expressed in extrathyroidal tissues, and whether it participates directly in the pathogenesis of Graves' ophthalmopathy (GO) are unclear. We sought to detect the expression of TSHr messenger ribonucleic acid (mRNA) and protein in orbital adipose/connective tissue specimens and in human orbital preadipocyte fibroblast cultures using liquid hybridization analysis and immunohistochemical methods. We demonstrated intact and variant TSHr mRNA transcripts and TSHr-like immunoreactivity in orbital adipose/connective tissue specimens from patients with GO. In addition, TSHr-like immunoreactivity was detected in early passage GO preadipocyte fibroblast cultures that were shown to include some adipose cells. In contrast, neither TSHr mRNA nor protein was detected in normal orbital adipose/connective tissue specimens or in late passage GO orbital fibroblast cultures containing no lipid-laden adipose cells. In conclusion, we showed that TSHr is expressed in the adipose/connective tissue of the diseased orbit in GO. In addition, TSHr is demonstrable in early passage GO preadipocyte orbital fibroblast cultures that contain a subpopulation of adipocytes. Subsequent passaging of these cells results in the loss of both TSHr expression and adipocyte-specific staining. These results suggest that both the expression of this receptor and the accumulation of adipose tissue in the orbit in GO may be induced in vivo by a humoral factor(s) not present in the cell culture environment.
An increased accumulation of glycosaminoglycans (GAG) in retrobulbar tissues has been reported in patients with thyroid eye disease. We examined the quantitative urinary GAG excretion in 101 patients with Graves' ophthalmopathy of different classes, 36 patients with Graves' hyperthyroidism without ophthalmopathy, 14 patients with toxic nodular goitre and 103 control subjects. Glycosaminoglycans were isolated from 24-h urine collections by precipitation with cetylpyridinium chloride and ethanol followed by photometrical quantification of hexuronic acids after reaction with carbazole. In comparison with the control group (15.8, 10.4, 21.6 mg/24 h; median, 25th, 75th percentile) a significant (P less than 0.005) elevation of urinary GAG excretion was found in patients with ophthalmopathy (19.2, 12.2, 28.7 mg/24 h), whereas patients with Graves' hyperthyroidism and no ophthalmopathy (16.2, 11.9, 21.7 mg/24 h) and patients with toxic nodular goitre (15.8, 11.5, 21.2 mg/24 h) exhibited no markedly increased values. Especially, patients with active, untreated ophthalmopathy showed on average a twofold increase (36.7, 28.1, 48.4 mg/24 h) in urinary GAG excretion. In contrast, high values were not found in patients with inactive ophthalmopathy and elevated values decreased under treatment, which correlated with clinical findings. Further, relapses were also accompanied by high GAG excretion. Thus, using a simple laboratory method, quantitative determination of urinary GAG excretion appears to present an effective parameter for the activity of Graves' ophthalmopathy.
CONNECTIVE tissue imparts cohesion, strength, and form to the organs that it invests. It is comprised of several discrete cellular and noncellular components. The fibroblast and its more specialized derivatives (such as chondrocytes and osteocytes) elaborate and release several important molecules such as fibrous proteins (collagen), attachment proteins (fibronectin), glycoproteins, and ground substance. In this article we review the now abundant evidence that fibroblasts and their products are important mediators of some peripheral expressions of thyroid disease, including myxedema, pretibial dermopathy, thyroid acropachy, and ophthalmopathy of Graves' disease. Our review concentrates predominantly on the glycosaminoglycans that comprise ground substance. The fibrous proteins are given less attention.
The early prejudice that the ground substance and connective tissue in general were rather unimportant becomes apparent in a quote attributed to Von Haller (1), who in 1757 wrote that “it is evident that a considerable part of the human body consists of matter which for so many centuries has been regarded as rubbish.” Yet it is widely appreciated in contemporary biology that ground substance and the connective tissues play a crucial role in defining the microenvironment for specialized cells to function. They are important in cell attachment and cell-to-cell communication, and they influence the manner in which cells negotiate the extracellular milieu. A brief review of the physicochemical properties of the glycosaminoglycans that compose ground substance precedes the more detailed analysis of the impact that thyroid dysfunction can have on its synthesis and disposal.
The administration of a high iodide dose (HID; 10 μg/day) to goitrous mice is known to induce thyroid cell necrosis and inflammation, which, in most strains, is transient. In this study, we analyzed the effects of iodide in autoimmune prone non-obese diabetic (NOD) mice.
Control NOD mice fed a standard diet (MID; 1 μg I/day) or HID did not spontaneously develop thyroiditis. In NOD mice previously made goitrous, HID provoked thyroid cell necrosis and diffuse inflammation within 4 days. Inflammatory cells consisted of MHC-class II+ antigen-presenting cells, CD4+ T helper cells and CD8+ T suppressor/cytotoxic cells. After 96 days of treatment with HID, thyroiditis similar to Hashimoto's disease was obtained in 100% of the animals, with destruction of thyroid follicles, large clusters of T and B cells, and antithyroid antibodies in the plasma. When treating goitrous mice with MID, no cell necrosis was observed and no autoimmune thyroiditis was obtained. The early iodide-induced cell necrosis and inflammation may thus be considered as an important factor in the induction and persistence of autoimmune thyroiditis in individuals carrying a genetic susceptibility to autoimmune disease.
Journal of Endocrinology (1995) 147, 311–320
RNA was isolated from fibroblasts from the retroocular area, from endomysial fibroblasts obtained from orbital lateral rectus muscle, and from abdominal skin fibroblasts. The RNA was reverse transcribed into cDNA which was then used as a template for PCR with primers encompassing a portion (nucleotides 989-1235) of the extra-cellular domain of the human TSH receptor (hTSH-R). A definite 247 BP product was detected from fibroblast RNA by ethidium bromide staining, and was confirmed by hybridization with labelled hTSH-R cDNA. The product had homology with the known TSH-R cDNA. These studies indicate that human fibroblasts can express hTSH-R, and they suggest that a cross reactive immunologic response between anti-hTSH-R and these fibroblast TSH receptors may play a role in the genesis of Graves' ophthalmopathy.
The TSH receptor (TSHR) has been proposed as an antigenic link between the thyroid and the orbit; TSHR transcripts have been demonstrated by other groups, one in orbital tissue and the other in orbital and dermal fibroblasts. In a previous study we were unable to demonstrate transcripts for the complete TSHR in retroocular muscle containing also fibroblasts. We now confirm this finding. A 1.3-kilobase variant of the TSHR messenger ribonucleic acid (mRNA) has been described in normal and Graves' thyroids; it contains exons 1-8 of the major mRNA species and a unique 3'-sequence predicted to encode further amino acids and a polyadenylated tail. Lacking the membrane-spanning region, the corresponding variant protein, if expressed, is not expected to couple to G-proteins. Using primers specific for this variant in reverse polymerase chain reaction experiments, Southern blotting and frequencies, we demonstrate the presence of this transcript in normal and Graves' thyroid, extraocular muscle, peripheral blood mononuclear cells, and, to a lesser extent, in fat and fibroblasts. TSH-mediated protein synthesis, cAMP, and glycosaminoglycan production have been measured in cultured fibroblasts. At 5 mU/mL, bovine TSH stimulated glycosaminoglycan production, but recombinant TSH did not, even at higher concentrations, suggesting that contaminating factors are responsible. Together the data do not support the presence of a functional complete TSHR in orbital tissue. However, they are compatible with a role for the extracellular portion of the receptor as a nonfunctional autoantigen and provide some explanation for the conflicting results with regard to the relevance of the TSHR in the pathophysiology of thyroid-associated ophthalmopathy.
It is not clear whether the ophthalmopathy present in Graves' disease is related to autoimmune reactions to common thyroid/orbit components or is due to specific ocular antigens unrelated to the thyroid. In Graves' disease, serum antibodies to the thyrotropin receptor (TSH-R) can stimulate thyroid function, but no link between the TSH-R and ocular tissues has been found. We have shown, by polymerase chain reaction amplification of specific cDNA, that mature TSH-R mRNA is expressed in the retro-orbital tissue of both healthy subjects and patients with Graves' disease. Of other tissues and cells tested (fibroblasts, lymphocytes, muscle, and thyroid), only thyroid tissue expressed the TSH-R mRNA.
Pretibial myxedema is an uncommon manifestation of Graves disease, and little information is available regarding its natural course and its relation to other manifestations of Graves disease. We reviewed 150 consecutive cases with the diagnosis of pretibial myxedema over a 20-year period in a referral center. Only 1 patient in this group did not have ophthalmopathy, whereas 88% had significant proptosis and 30% required orbital decompression surgery. Dermopathy was a late manifestation of Graves disease, and its onset usually followed the diagnosis of hyperthyroidism and ophthalmopathy. In a few patients, dermopathy preceded diagnosis of hyperthyroidism or onset of ophthalmopathy. Fourteen patients were never clinically hyperthyroid; spontaneous hypothyroidism had developed in 11 in this group. All cases involved the lower extremities, with only 1 patient having combined upper and lower extremity involvement. The most common form of thyroid dermopathy was nonpitting edema, followed by nodular and plaque forms, which occurred with equal frequency. The polypoid form occurred in 1 patient and the elephantiasic form in another; 7.3% had thyroid acropachy. Follow-up was available for 120 patients (range, 3 mo to 19 yr; mean, 3.2 yr), and complete remission was observed in only 12 patients. Topically applied corticosteroid therapy was used in 76 patients, and in this group 38% had sustained long-term partial remission, as opposed to 18% in the group receiving no corticosteroid therapy.
The involvement of autoantibodies in the extrathyroidal manifestations of Graves' disease has been the subject of extensive investigation, with fairly inconclusive results to date. We investigated the presence of immunoglobulin A (IgA) and IgG antibodies in patients with Graves' disease and pretibial myxedema (PTM; n = 21) as well as those with Graves' disease with thyroid-associated ophthalmopathy (TAO; n = 10), Graves' disease with no clinical evidence of extrathyroidal manifestations (n = 11), Hashimoto's thyroiditis (n = 9), type 1 diabetes mellitus (n = 10), systemic lupus erythematosus (n = 9) and normal individuals (n = 17). We looked for antibodies to both retroocular muscle and dermal fibroblasts as well as to thyroid peroxidase, thyroid microsomal antigen, thyroglobulin, and human eye muscle membranes. IgA class antibodies to microsomal antigen (30-50% of patients), thyroid peroxidase (5-20%), and human eye muscle membrane (0-26%) antigens were found in the various groups of patients with Graves' disease. With each of these antigens, serum from patients with PTM showed the greatest binding. Highly significant IgA binding was shown by PTM serum to both dermal (P < 0.001) and retroocular muscle (P < 0.001) fibroblasts from 12 different donors. Serum from Graves' patients with and without TAO and that from Hashimoto's thyroiditis patients reacted significantly with 4 of the 12 fibroblasts lines. In contrast, IgG binding was only found for 3 of the 12 fibroblast lines using patient serum. The IgA binding to fibroblasts shown by PTM patients was predominantly of the IgA2 subclass. The activity was absorbed out by both fibroblasts and thyroid cells. In immunoblotting studies, PTM patient serum reacted with a 54-kilodalton dermal fibroblast antigen and a 66-kilodalton retroocular fibroblast antigen. No binding to these antigens was seen with serum from normal controls or patients without PTM. Further elucidation of the nature of this fibroblast antigen will help to determine the role of IgA autoantibodies in the extrathyroidal manifestations of Graves' disease.
The pathogenesis of the extrathyroidal manifestations of Graves' disease-ophthalmopathy and pretibial myxedema (Graves' dermopathy)-involves fibroblast activation and increased mucin (glycosaminoglycan) production. It is nuclear why fibroblasts are activated at these sites and evidence for site-specific and generalized fibroblast activation is conflicting. One previous report has demonstrated an increase in glycosaminoglycan deposition in the forearm skin of patients with Graves' disease but without pretibial myxedema. We have sought to confirm the existence of subclinical dermopathy in the forearm tissue from patients with untreated (UG) and treated (TG) Graves' disease and compared the histological changes with normal controls (C), treated toxic nodular goiter (MNG) and Graves' dermopathy specimens (PTM), using stains for mucin, elastin, glycosaminoglycans (GAGs), and HLA-DR molecules. Four of 4 PTM specimens stained positive for mucin, with varying sparse, fragmented, or dense elastin fibers. Four of 5 PTM specimens stained heavily for GAGs using colloidal iron and 2 of 5 stained heavily using colloidal gold. None of the patients in groups UG, TG, MNG, or the controls, showed mucin deposition or elastin changes. Mild staining with colloidal gold for GAGs was seen in 1 each of the UG, the TG, and MNG groups, and 4 of 8 controls. Heavy staining with colloidal iron for GAGs was seen in 1 TG patient and 1 control, while moderate staining was found in several TG, UG, and controls. In 2 of 4 PTM specimens the monoclonal antibody CR3/43 (against HLA-DR) stained frequent dermal fibroblast-like cells and in 2 a lymphocytic infiltrate was seen. Only 1 of 8 UG patients had multiple CR3/43 staining cells present in the dermis: 3 of 8 TG and 1 of 8 controls had a few CR3/43 stained cells. Overall we found no evidence of dermal mucin deposition in the forearms of 16 patients with Graves' disease and a similar GAG distribution to normal controls. HLA-DR expression by fibroblast-like cells in the dermis suggests activation of these cells in the dermis of the PTM specimens, but no evidence of widespread fibroblast activation was found in the forearms of patients with Graves' disease.
We have studied the cellular localization of thyrotropin receptor (TSH-R) mRNA in orbital fat and extraocular muscle tissues from patients with thyroid-associated ophthalmopathy (TAO) using Northern blot, reverse transcriptase polymerase chain reaction (RT-PCR), and in situ hybridization, and we correlated the findings with clinical estimates of ophthalmopathy. Although we failed to detect TSH-R mRNA in orbital tissues by Northern blot, TSH-R cDNA was amplified in orbital fat tissue from 13 of 25 patients with TAO and from 2 of 4 control subjects, in eye muscle tissue from 2 out of 7 patients with TAO, and in cultured orbital fibroblasts and subcutaneous fibroblasts from TAO patients. In situ hybridization showed that TSH-R mRNA was detected in cultured orbital fibroblasts as well as skin fibroblasts obtained from the patient. Furthermore, the expression of TSH-R mRNA in orbital fat tissue from patients with TAO significantly correlated with the orbital fat volume and the severity of ophthalmopathy, especially the extent of eye muscle dysfunction. These results suggest that the expression of TSH-R in the orbit, especially fibroblasts, may play a role in the pathogenesis and clinical manifestations of the ophthalmopathy in patients with TAO, although a secondary effect, involving fibroblasts in TAO is also possible.
Several lines of experimental and clinical evidence favor a close etiologic link between Graves' disease and its associated extrathyroidal manifestations, ophthalmopathy and pretibial dermopathy. The human TSHR represents a candidate antigen shared between the thyroid gland and the involved extrathyroidal sites in Graves' disease. Here, we demonstrate that ribonucleic acid encoding exons 1-10 of human TSHR can be detected in fibroblasts derived from the affected orbital and pretibial space in patients with Graves' ophthalmopathy and pretibial dermopathy. RNA prepared from cultured fibroblasts was reverse transcribed and the resulting cDNA amplified by the polymerase chain reaction using primers spanning exons 1 through 10 of TSHR. The predicted transcripts (1890 and 2092 bp, respectively) were obtained with cDNA derived from orbital and pretibial fibroblasts of all patients with GO and PTM, and orbital fibroblasts of one healthy individual, and confirmed by southern hybridization. Sequencing of TSHR transcripts confirmed their identity with the reported nucleotide sequence of the human TSHR. Immunostaining using both monoclonal and polyclonal antibodies directed against the recombinant human TSHR revealed specific TSHR-like immunoreactivity in fibroblasts and adipose/connective tissue derived from the orbital and pretibial space of patients with GO and PTD, but not in normal individuals or control tissues. Detection, within the orbital and pretibial tissues, of RNA encoding nonvariant hTSHR and of immunoreactivity for this important autoantigen in Graves' disease suggests that the pathogenic role of the TSHR may extend beyond the thyroid gland, and may include the associated extrathyroidal manifestations.
Thyroid eye disease (TED) has an autoimmune etiology, but the nature of the autoantigen that is the target of the initiating event remains unknown. A number of candidates have been proposed based on Western blotting, library screening, and deduction from sequence similarity. A strong favorite is the thyrotropin receptor (TSHR), which is the target of the thyroid stimulating antibodies (TSAB) of Graves' disease (GD). We have recently demonstrated TSHR transcripts in orbital adipose tissue from a patient with TED by Northern blot, transcripts in normal adipose tissue being at the limit of detection. We have shown that the transcripts are translated into protein by immunohistochemical analysis using two monoclonal antibodies to the TSHR generated by genetic immunization. TSHR immunoreactivity is associated with elongated cells with the appearance of a fibroblast, often adjacent to clusters of adipocytes, in orbital biopsies from patients with TED but not in strabismus or pseudotumor biopsies. In animal studies, we have transferred thyroiditis to naive BALBc and NOD mice, using T cells primed to the human TSHR, either using the receptor expressed as a bacterial fusion protein or by genetic immunization. The BALBc develop a Th2-type response to the receptor, but the NOD a Th1-type with thyrocyte destruction. Orbital pathology, edema, infiltration by mast cells and lymphocytes, and adipose accumulation was also induced in 68% of the BALBc but none of the NOD mice. Together these data indicate that the preadipocyte expresses the TSHR and that a Th2 autoimmune response to the receptor may be an initiating event in TED.
The basis for the extrathyroidal manifestations of Graves' ophthalmopathy (GO) and dermopathy are not well understood. We describe immunohistochemical studies on the skin of a patient with an extreme, elephantiasic form of Graves' dermopathy that developed after periods of prolonged standing with dependent edema. Excision of part of the lesion with subsequent skin grafting from a normal donor site resulted in recurrence of the disease at the original site as well as in development of disease at the donor site. A murine monoclonal antibody reacted with the thyrotropin receptor (TSHR) or a cross-reacting protein in fibroblast-like cells in the patient's upper dermis and, surprisingly, with dermal cells from unaffected individuals. The patient's dermis containing lymphoid follicles comprising B cells and CD3+, CD4+ T cells, with few CD8+ T cells. CD21+ cells (most likely follicular dendritic cells) were also present in the dermis. Based on past and present observations, we raise an unifying hypothesis to explain the diverse extrathyroidal manifestations of Graves' disease and their apparent lack of association with TSHR autoantibodies. As opposed to the present concept that these phenomena relate to site-specific properties on preadipocytes or fibroblasts, we suggest that clinically evidence GO and dermopathy are primarily caused by local factors (particularly in the orbit) superimposed on a systemic, low-grade connective tissue inflammation.