1
|
Yao B, Yang C, Pan C, Li Y. Thyroid hormone resistance: Mechanisms and therapeutic development. Mol Cell Endocrinol 2022; 553:111679. [PMID: 35738449 DOI: 10.1016/j.mce.2022.111679] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 05/03/2021] [Accepted: 05/09/2022] [Indexed: 10/18/2022]
Abstract
As an essential primary hormone, thyroid hormone (TH) is indispensable for human growth, development and metabolism. Impairment of TH function in several aspects, including TH synthesis, activation, transportation and receptor-dependent transactivation, can eventually lead to thyroid hormone resistance syndrome (RTH). RTH is a rare syndrome that manifests as a reduced target cell response to TH signaling. The majority of RTH cases are related to thyroid hormone receptor β (TRβ) mutations, and only a few RTH cases are associated with thyroid hormone receptor α (TRα) mutations or other causes. Patients with RTH suffer from goiter, mental retardation, short stature and bradycardia or tachycardia. To date, approximately 170 mutated TRβ variants and more than 20 mutated TRα variants at the amino acid level have been reported in RTH patients. In addition to these mutated proteins, some TR isoforms can also reduce TH function by competing with primary TRs for TRE and RXR binding. Fortunately, different treatments for RTH have been explored with structure-activity relationship (SAR) studies and drug design, and among these treatments. With thyromimetic potency but biochemical properties that differ from those of primary TH (T3 and T4), these TH analogs can bypass specific defective transporters or reactive mutant TRs. However, these compounds must be carefully applied to avoid over activating TRα, which is associated with more severe heart impairment. The structural mechanisms of mutation-induced RTH in the TR ligand-binding domain are summarized in this review. Furthermore, strategies to overcome this resistance for therapeutic development are also discussed.
Collapse
Affiliation(s)
- Benqiang Yao
- The State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Fujian, 361005, China
| | - Chunyan Yang
- The State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Fujian, 361005, China.
| | - Chengxi Pan
- The State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Fujian, 361005, China
| | - Yong Li
- The State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Fujian, 361005, China.
| |
Collapse
|
2
|
Groeneweg S, Peeters RP, Visser TJ, Visser WE. Therapeutic applications of thyroid hormone analogues in resistance to thyroid hormone (RTH) syndromes. Mol Cell Endocrinol 2017; 458:82-90. [PMID: 28235578 DOI: 10.1016/j.mce.2017.02.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/17/2017] [Accepted: 02/18/2017] [Indexed: 10/20/2022]
Abstract
Thyroid hormone (TH) is crucial for normal development and metabolism of virtually all tissues. TH signaling is predominantly mediated through binding of the bioactive hormone 3,3',5-triiodothyronine (T3) to the nuclear T3-receptors (TRs). The intracellular TH levels are importantly regulated by transporter proteins that facilitate the transport of TH across the cell membrane and by the three deiodinating enzymes. Defects at the level of the TRs, deiodinases and transporter proteins result in resistance to thyroid hormone (RTH) syndromes. Compounds with thyromimetic potency but with different (bio)chemical properties compared to T3 may hold therapeutic potential in these syndromes by bypassing defective transporters or binding to mutant TRs. Such TH analogues have the potential to rescue TH signaling. This review describes the role of TH analogues in the treatment of RTH syndromes. In particular, the application of 3,3',5-triiodothyroacetic acid (Triac) in RTH due to defective TRβ and the role of 3,5-diiodothyropropionic acid (DITPA), 3,3',5,5'-tetraiodothyroacetic acid (Tetrac) and Triac in MCT8 deficiency will be highlighted.
Collapse
Affiliation(s)
- Stefan Groeneweg
- Department of Internal Medicine, Academic Center for Thyroid Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Robin P Peeters
- Department of Internal Medicine, Academic Center for Thyroid Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Theo J Visser
- Department of Internal Medicine, Academic Center for Thyroid Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - W Edward Visser
- Department of Internal Medicine, Academic Center for Thyroid Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands.
| |
Collapse
|
3
|
Groeneweg S, Peeters RP, Visser TJ, Visser WE. Triiodothyroacetic acid in health and disease. J Endocrinol 2017; 234:R99-R121. [PMID: 28576869 DOI: 10.1530/joe-17-0113] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 05/30/2017] [Indexed: 12/16/2022]
Abstract
Thyroid hormone (TH) is crucial for development and metabolism of many tissues. The physiological relevance and therapeutic potential of TH analogs have gained attention in the field for many years. In particular, the relevance and use of 3,3',5-triiodothyroacetic acid (Triac, TA3) has been explored over the last decades. Although TA3 closely resembles the bioactive hormone T3, differences in transmembrane transport and receptor isoform-specific transcriptional activation potency exist. For these reasons, the application of TA3 as a treatment for resistance to TH (RTH) syndromes, especially MCT8 deficiency, is topic of ongoing research. This review is a summary of all currently available literature about the formation, metabolism, action and therapeutic applications of TA3.
Collapse
Affiliation(s)
- Stefan Groeneweg
- Department of Internal Medicine and Academic Center for Thyroid DiseasesErasmus University Medical Center, Rotterdam, The Netherlands
| | - Robin P Peeters
- Department of Internal Medicine and Academic Center for Thyroid DiseasesErasmus University Medical Center, Rotterdam, The Netherlands
| | - Theo J Visser
- Department of Internal Medicine and Academic Center for Thyroid DiseasesErasmus University Medical Center, Rotterdam, The Netherlands
| | - W Edward Visser
- Department of Internal Medicine and Academic Center for Thyroid DiseasesErasmus University Medical Center, Rotterdam, The Netherlands
| |
Collapse
|
4
|
De Luca F, Salzano G, Zirilli G, Calafiore M, Corica D, Sferlazzas C. Management of hyperthyroidism in children. Expert Rev Endocrinol Metab 2016; 11:301-309. [PMID: 30058924 DOI: 10.1080/17446651.2016.1199953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Treatment of hyperthyroidism in children differs according to its etiology; in particular, the optimal therapy of Graves' disease (GD) remains a matter of debate and there is currently no evidence-based therapeutic strategy that is universally adopted in all the countries. Areas covered: The most recent treatment strategies in the different pediatric conditions which may be associated with hyperthyroidism. We searched PubMed and Cochrane (1990 to 2016) in order to identify articles to include in this review using the following terms: Hyperthyroidism, Childhood, Antithyroid drug therapy, Thyroidectomy, Radioactive iodine. Expert commentary: Although pharmacological therapy represents the first-line approach for GD children, we recommend to individualize, as much as possible, the overall therapeutic approach, with no prejudices towards radical therapies, particularly in the cases with frequent relapses. Clinical and laboratory preferential criteria for an individualized therapeutic approach to GD children are given. Treatment procedures for hyperthyroid children without GD are also discussed.
Collapse
Affiliation(s)
- Filippo De Luca
- a Department of Human Pathology of Adulthood and Childhood , University of Messina , Messina , Italy
| | - Giuseppina Salzano
- a Department of Human Pathology of Adulthood and Childhood , University of Messina , Messina , Italy
| | - Giuseppina Zirilli
- a Department of Human Pathology of Adulthood and Childhood , University of Messina , Messina , Italy
| | - Mariarosa Calafiore
- a Department of Human Pathology of Adulthood and Childhood , University of Messina , Messina , Italy
| | - Domenico Corica
- a Department of Human Pathology of Adulthood and Childhood , University of Messina , Messina , Italy
| | - Concetta Sferlazzas
- a Department of Human Pathology of Adulthood and Childhood , University of Messina , Messina , Italy
| |
Collapse
|
5
|
Single-dose T3 administration: kinetics and effects on biochemical and physiological parameters. Ther Drug Monit 2015; 37:110-8. [PMID: 24977379 DOI: 10.1097/ftd.0000000000000113] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND As changes in thyroid stimulating hormone (TSH), thyroid hormones, and vital signs after administration of a single dose of liothyronine have typically only been documented for 24 hours, we documented these parameters more than 96 hours. METHODS Blood samples were obtained for 4 days after administration of 50-mcg liothyronine to 12 healthy euthyroid participants. Concentrations of total and free triiodothyronine, free and total thyroxine, and TSH were measured. Vital signs were documented. RESULTS Triiodothyronine concentrations peaked at 2.5 hours after liothyronine administration. Heart rate (HR) increased by 5 hours after liothyronine administration, subsequently reaching a value higher than baseline (P = 0.009). Suppression of TSH concentrations began at 2 hours. The nadir TSH value at 12 hours was significantly different from baseline (P < 0.001) and remained lower than the baseline value for 2-3 days. CONCLUSIONS A single dose of liothyronine has both short-term and long-term effects. There is clearly a different lag time between the serum concentrations of triiodothyronine and its effects on the heart and pituitary, respectively. The increase in serum triiodothyronine concentration occurred within hours and was then followed by an increase in HR. The increased HR was transient and was followed by a reduction in TSH concentration. The suppression of TSH was delayed but was more sustained. Thus, sustained TSH reduction beyond 24 hours was achieved by a single dose of liothyronine that produced only brief increases in serum triiodothyronine levels and transient increases in HR.
Collapse
|
6
|
Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, Mechanick JI, Pessah-Pollack R, Singer PA, Woeber KA. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Endocr Pract 2013; 18:988-1028. [PMID: 23246686 DOI: 10.4158/ep12280.gl] [Citation(s) in RCA: 611] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Hypothyroidism has multiple etiologies and manifestations. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions. This paper describes evidence-based clinical guidelines for the clinical management of hypothyroidism in ambulatory patients. METHODS The development of these guidelines was commissioned by the American Association of Clinical Endocrinologists (AACE) in association with American Thyroid Association (ATA). AACE and the ATA assembled a task force of expert clinicians who authored this article. The authors examined relevant literature and took an evidence-based medicine approach that incorporated their knowledge and experience to develop a series of specific recommendations and the rationale for these recommendations. The strength of the recommendations and the quality of evidence supporting each was rated according to the approach outlined in the American Association of Clinical Endocrinologists Protocol for Standardized Production of Clinical Guidelines-2010 update. RESULTS Topics addressed include the etiology, epidemiology, clinical and laboratory evaluation, management, and consequences of hypothyroidism. Screening, treatment of subclinical hypothyroidism, pregnancy, and areas for future research are also covered. CONCLUSIONS Fifty-two evidence-based recommendations and subrecommendations were developed to aid in the care of patients with hypothyroidism and to share what the authors believe is current, rational, and optimal medical practice for the diagnosis and care of hypothyroidism. A serum thyrotropin is the single best screening test for primary thyroid dysfunction for the vast majority of outpatient clinical situations. The standard treatment is replacement with L-thyroxine. The decision to treat subclinical hypothyroidism when the serum thyrotropin is less than 10 mIU/L should be tailored to the individual patient.
Collapse
Affiliation(s)
- Jeffrey R Garber
- Endocrine Division, Harvard Vanguard Medical Associates, Boston, Massachusetts 02215, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Horn S, Kersseboom S, Mayerl S, Müller J, Groba C, Trajkovic-Arsic M, Ackermann T, Visser TJ, Heuer H. Tetrac can replace thyroid hormone during brain development in mouse mutants deficient in the thyroid hormone transporter mct8. Endocrinology 2013; 154:968-79. [PMID: 23307789 DOI: 10.1210/en.2012-1628] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The monocarboxylate transporter 8 (MCT8) plays a critical role in mediating the uptake of thyroid hormones (THs) into the brain. In patients, inactivating mutations in the MCT8 gene are associated with a severe form of psychomotor retardation and abnormal serum TH levels. Here, we evaluate the therapeutic potential of the TH analog 3,5,3',5'-tetraiodothyroacetic acid (tetrac) as a replacement for T(4) in brain development. Using COS1 cells transfected with TH transporter and deiodinase constructs, we could show that tetrac, albeit not being transported by MCT8, can be metabolized to the TH receptor active compound 3,3',5-triiodothyroacetic acid (triac) by type 2 deiodinase and inactivated by type 3 deiodinase. Triac in turn is capable of replacing T(3) in primary murine cerebellar cultures where it potently stimulates Purkinje cell development. In vivo effects of tetrac were assessed in congenital hypothyroid Pax8-knockout (KO) and Mct8/Pax8 double-KO mice as well as in Mct8-KO and wild-type animals after daily injection of tetrac (400 ng/g body weight) during the first postnatal weeks. This treatment was sufficient to promote TH-dependent neuronal differentiation in the cerebellum, cerebral cortex, and striatum but was ineffective in suppressing hypothalamic TRH expression. In contrast, TSH transcript levels in the pituitary were strongly down-regulated in response to tetrac. Based on our findings we propose that tetrac administration offers the opportunity to provide neurons during the postnatal stage with a potent TH receptor agonist, thereby eventually reducing the neurological damage in patients with MCT8 mutations without deteriorating the thyrotoxic situation in peripheral tissues.
Collapse
Affiliation(s)
- Sigrun Horn
- Leibniz Institute for Age Research/Fritz Lipmann Institute, D-07745 Jena, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, Mechanick JI, Pessah-Pollack R, Singer PA, Woeber KA. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Thyroid 2012; 22:1200-35. [PMID: 22954017 DOI: 10.1089/thy.2012.0205] [Citation(s) in RCA: 536] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Hypothyroidism has multiple etiologies and manifestations. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions. This paper describes evidence-based clinical guidelines for the clinical management of hypothyroidism in ambulatory patients. METHODS The development of these guidelines was commissioned by the American Association of Clinical Endocrinologists (AACE) in association with American Thyroid Association (ATA). AACE and the ATA assembled a task force of expert clinicians who authored this article. The authors examined relevant literature and took an evidence-based medicine approach that incorporated their knowledge and experience to develop a series of specific recommendations and the rationale for these recommendations. The strength of the recommendations and the quality of evidence supporting each was rated according to the approach outlined in the American Association of Clinical Endocrinologists Protocol for Standardized Production of Clinical Guidelines-2010 update. RESULTS Topics addressed include the etiology, epidemiology, clinical and laboratory evaluation, management, and consequences of hypothyroidism. Screening, treatment of subclinical hypothyroidism, pregnancy, and areas for future research are also covered. CONCLUSIONS Fifty-two evidence-based recommendations and subrecommendations were developed to aid in the care of patients with hypothyroidism and to share what the authors believe is current, rational, and optimal medical practice for the diagnosis and care of hypothyroidism. A serum thyrotropin is the single best screening test for primary thyroid dysfunction for the vast majority of outpatient clinical situations. The standard treatment is replacement with L-thyroxine. The decision to treat subclinical hypothyroidism when the serum thyrotropin is less than 10 mIU/L should be tailored to the individual patient.
Collapse
Affiliation(s)
- Jeffrey R Garber
- Endocrine Division, Harvard Vanguard Medical Associates, Boston, Massachusetts 02215, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Anzai R, Adachi M, Sho N, Muroya K, Asakura Y, Onigata K. Long-term 3,5,3'-triiodothyroacetic acid therapy in a child with hyperthyroidism caused by thyroid hormone resistance: pharmacological study and therapeutic recommendations. Thyroid 2012; 22:1069-75. [PMID: 22947347 DOI: 10.1089/thy.2011.0450] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND The effectiveness of short-term 3,5,3'-triiodothyroacetic acid (TRIAC) therapy for the treatment of hyperthyroidism caused by thyroid hormone resistance (RTH) has been documented. Here, we report a 3-year course of TRIAC therapy in an RTH boy, with a quantitative evaluation of the therapeutic effects and pharmacological study of TRIAC. PATIENT FINDINGS The gene encoding the thyroid hormone receptor beta (THRB) of the patient carries a P453T mutation. During treatment with up to 3.0 mg TRIAC per day, reduction in the thyroid volume, resolution of supraventricular arrhythmia, and decrease in thyroid-stimulating hormone (TSH) and free-thyroxine (FT4) levels were achieved. In addition, attention-deficit hyperactivity disorder (ADHD) symptoms improved, with a concomitant decline in the ADHD Rating Scale score. SUMMARY A TRIAC pharmacokinetic study, conducted using triiodothyronine level as a surrogate for TRIAC level, demonstrated that TRIAC disappears from the circulation rapidly and has a shorter duration of TSH secretion inhibitory effect in the RTH patient compared to that in the control subject. Studies of TSH and FT4 levels over a period of 3 years indicated that the TRIAC effect is dose dependent. CONCLUSIONS TRIAC was effective and safe in ameliorating the effects of hyperthyroidism and ADHD symptoms in a child with known genetic RTH. Further, it was demonstrated that TRIAC has a short half-life and functions dose dependently.
Collapse
Affiliation(s)
- Rie Anzai
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, Yokohama, Japan
| | | | | | | | | | | |
Collapse
|
10
|
Eisenberg M, Samuels M, DiStefano JJ. Extensions, validation, and clinical applications of a feedback control system simulator of the hypothalamo-pituitary-thyroid axis. Thyroid 2008; 18:1071-85. [PMID: 18844475 PMCID: PMC2962855 DOI: 10.1089/thy.2007.0388] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND We upgraded our recent feedback control system (FBCS) simulation model of human thyroid hormone (TH) regulation to include explicit representation of hypothalamic and pituitary dynamics, and updated TH distribution and elimination (D&E) parameters. This new model greatly expands the range of clinical and basic science scenarios explorable by computer simulation. METHODS We quantified the model from pharmacokinetic (PK) and physiological human data and validated it comparatively against several independent clinical data sets. We then explored three contemporary clinical issues with the new model: combined triiodothyronine (T(3))/thyroxine (T(4)) versus T(4)-only treatment, parenteral levothyroxine (L-T(4)) administration, and central hypothyroidism. RESULTS Combined T(3)/T(4) therapy--In thyroidectomized patients, the L-T(4)-only replacement doses needed to normalize plasma T(3) or average tissue T(3) were 145 microg L-T(4)/day or 165 microg L-T(4)/day, respectively. The combined T(4) + T(3) dosing needed to normalize both plasma and tissue T(3) levels was 105 microg L-T(4) + 9 microg T(3) per day. For all three regimens, simulated mean steady-state plasma thyroid-stimulating hormone (TSH), T(3), and T(4) was within normal ranges (TSH: 0.5-5 mU/L; T(4): 5-12 microg/dL; T(3): 0.8-1.9 ng/mL). Parenteral T(4) administration--800 microg weekly or 400 microg twice weekly normalized average tissue T(3) levels both for subcutaneous (SC) and intramuscular (IM) routes of administration. TSH, T(3), and T(4) levels were maintained within normal ranges for all four of these dosing schemes (1x vs. 2x weekly, SC vs. IM). Central hypothyroidism--We simulated steady-state plasma T(3), T(4), and TSH concentrations in response to varying degrees of central hypothyroidism, reducing TSH secretion from 50% down to 0.1% of normal. Surprisingly, TSH, T(3), and T(4) plasma concentrations remained within normal ranges for TSH secretion as low as 25% of normal. CONCLUSIONS Combined T(3)/T(4) treatment--Simulated standard L-T(4)-only therapy was sufficient to renormalize average tissue T(3) levels and maintain normal TSH, T(3), and T(4) plasma levels, supporting adequacy of standard L-T(4)-only treatment. Parenteral T(4) administration-TSH, T(3), and T(4) levels were maintained within normal ranges for all four of these dosing schemes (1x vs. 2x weekly, SC vs. IM), supporting these therapeutic alternatives for patients with compromised L-T(4) gut absorption. Central hypothyroidism--These results highlight how highly nonlinear feedback in the hypothalamic-pituitary-thyroid axis acts to maintain normal hormone levels, even with severely reduced TSH secretion.
Collapse
Affiliation(s)
- Marisa Eisenberg
- Biocybernetics Laboratory, Departments of Computer Science, Medicine, and Biomedical Engineering, UCLA, Los Angeles, California 90095-1596, USA.
| | | | | |
Collapse
|
11
|
Iglesias P, Díez JJ. [Therapeutic possibilities in patients with selective pituitary resistance to thyroid hormones]. Med Clin (Barc) 2008; 130:345-50. [PMID: 18373914 DOI: 10.1157/13117351] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selective pituitary resistance to thyroid hormones (SPRTH) is a non-neoplastic form of inappropriate secretion of thyrotropin (TSH). The etiology of this hormonal resistance is linked to inactivating mutations in the thyroid hormone receptor beta (TR-beta) gene. These mutations affect critical portions of the receptor's triiodothyronine (T3)-binding domain. Clinically, SPRTH is characterized by hyperthyroidism with goiter and absence of pituitary mass in the morphologic study. Laboratory data show an elevation of free T3 and free thyroxine concentrations without suppression of TSH, with normal molar subunit alpha/TSH ratio. At this time, there is no specific therapy for SPRHT. Beta blockers, such as atenolol, and benzodiazepines have been used as a symptomatic therapy. Among the drugs with the capacity for reducing TSH secretion are TR agonists, such as triiodothyroacetic acid, D-thyroxine, triiodothyropropionic acid, and L-T3.
Collapse
Affiliation(s)
- Pedro Iglesias
- Servicio de Endocrinología, Hospital General, Segovia, España.
| | | |
Collapse
|
12
|
Messier N, Laflamme L, Hamann G, Langlois MF. In vitro effect of Triac on resistance to thyroid hormone receptor mutants: potential basis for therapy. Mol Cell Endocrinol 2001; 174:59-69. [PMID: 11306172 DOI: 10.1016/s0303-7207(00)00446-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Resistance to thyroid hormone (RTH) is a syndrome caused by a mutation in the carboxyl-terminal domain of the thyroid hormone receptor beta (TRbeta) gene. 3,5,3'-triiodothyroacetic acid (Triac) has been used on an empirical basis to treat RTH but its efficacy is still controversial. In previous studies, we demonstrated that Triac has TR isoform- and TRE-specific effects. In this report, we used five natural RTH mutations of the ligand-binding domain in both TRbeta1 and TRbeta2 isoforms for the evaluation of the effect of T3 and Triac on regulation of transcription and binding affinity. We show that Triac has superior activity on negatively and positively regulated promoters and higher binding affinity than T3 for a majority of TRbeta1 and TRbeta2 mutants. However, the difference of transcriptional activity and binding affinity between both ligands is less for RTH mutants than for wild type receptors. These results suggest that Triac could be a potential treatment for RTH patients.
Collapse
Affiliation(s)
- N Messier
- Department of Medicine, Division of Endocrinology, Faculty of Medicine, University of Sherbrooke, C.H.U.S., 12th Avenue North, Sherbrooke, Quebec, J1H 5N4, Canada
| | | | | | | |
Collapse
|
13
|
Safer JD, Colan SD, Fraser LM, Wondisford FE. A pituitary tumor in a patient with thyroid hormone resistance: a diagnostic dilemma. Thyroid 2001; 11:281-91. [PMID: 11327621 DOI: 10.1089/105072501750159750] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Resistance to thyroid hormone (RTH) is due to mutations in the beta-isoform of the thyroid hormone receptor (TR-beta). RTH patients display inappropriate secretion of thyrotropin-releasing hormone (TRH) from the hypothalamus and thyrotropin (TSH) from the anterior pituitary, despite elevated levels of thyroid hormone thyroxine (T4) and triiodothyronine (T3). Thyrotropin-secreting tumors are presumed to represent clonal expansion of abnormal cells. Because the diagnosis of TSH-secreting tumors tends to be delayed and curative surgical resection remains under 50%, early diagnosis is paramount. Current diagnostic strategies suggest that RTH patients are distinguishable from patients with TSH-secreting pituitary tumors by the use of standard laboratory tests and imaging. Here, we present a woman in whom the standard evaluation for inappropriate TSH secretion was insufficient to distinguish these entities. The patient had a low-normal TRH stimulation test and an unmeasurable alpha-glycoprotein subunit level; however, a pituitary magnetic resonance imaging (MRI) revealed an adenoma. More testing using a T3 suppression test supported a RTH diagnosis and a R438H mutation was found in the TR-beta gene. To our knowledge, this represents the first report of an apparently incidental pituitary adenoma in the setting of documented resistance to thyroid hormone. As such, it raises the question of whether RTH predisposes to pituitary hyperplasia and adenoma development.
Collapse
Affiliation(s)
- J D Safer
- Section of Endocrinology, Metabolism, and Diabetes, Boston University School of Medicine, Massachusetts 02118, USA.
| | | | | | | |
Collapse
|