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Matsuyama M, Sawada H, Inoue S, Hishinuma A, Sekiya R, Sato Y, Moritake H. Goiter in a 6-year-old patient with novel thyroglobulin gene variant (Gly145Glu) causing intracellular thyroglobulin transport disorder: Correlation between goiter size and the free T3 to free T4 ratio. Clin Pediatr Endocrinol 2022; 31:185-191. [PMID: 35928386 PMCID: PMC9297170 DOI: 10.1297/cpe.2022-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 04/12/2022] [Indexed: 11/04/2022] Open
Affiliation(s)
- Misayo Matsuyama
- Division of Pediatrics, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Hirotake Sawada
- Department of Fundamental Nursing, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Shinobu Inoue
- Division of Pediatrics, National Hospital Organization Miyazaki Higashi Hospital, Miyazaki, Japan
| | - Akira Hishinuma
- Department of Infection Control and Clinical Laboratory Medicine, Dokkyo Medical University, Mibu, Japan
| | - Ryo Sekiya
- Division of Surgery, Miyazaki Zenjinkai Hospital, Miyazaki, Japan
| | - Yuichiro Sato
- Departoment of Diagnostic Pathology, University of Miyazaki Hospital, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Hiroshi Moritake
- Division of Pediatrics, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
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Salas-Lucia F, Bianco AC. T3 levels and thyroid hormone signaling. Front Endocrinol (Lausanne) 2022; 13:1044691. [PMID: 36387853 PMCID: PMC9646642 DOI: 10.3389/fendo.2022.1044691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 10/17/2022] [Indexed: 11/26/2022] Open
Abstract
The clinical availability of tissue-specific biomarkers of thyroid hormone (TH) action constitutes a "holy grail" for the field. Scientists have investigated several TH-dependent markers, including the tissue content of triiodothyronine (T3)-the active form of TH. The study of animal models and humans indicates that the T3 content varies among different tissues, mostly due to the presence of low-affinity, high-capacity cytoplasmic T3 binding proteins. Nonetheless, given that T3 levels in the plasma and tissues are in equilibrium, T3 signaling is defined by the intracellular free T3 levels. The available techniques to assess tissue T3 are invasive and not clinically applicable. However, the tracer kinetic studies revealed that serum T3 levels can accurately predict tissue T3 content and T3 signaling in most tissues, except for the brain and pituitary gland. This is true not only for normal individuals but also for patients with hypo or hyperthyroidism-but not for patients with non-thyroidal illness syndrome. Given this direct relationship between serum and tissue T3 contents and T3 signaling in most tissues, clinicians managing patients with hypothyroidism could refocus attention on monitoring serum T3 levels. Future clinical trials should aim at correlating clinical outcomes with serum T3 levels.
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Chiang B, Kon YC. Severe Hypothyroxinemia in a Young Adult with Carbimazole-Treated T3-Predominant Graves' Hyperthyroidism, Reversed with L-Thyroxine Loading Immediately Post-Total Thyroidectomy. J ASEAN Fed Endocr Soc 2021; 36:85-9. [PMID: 34177093 DOI: 10.15605/jafes.036.01.07] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/08/2021] [Indexed: 11/17/2022] Open
Abstract
Patients with triiodothyronine (T3)-predominant Graves’ hyperthyroidism with markedly elevated serum thyroid stimulating immunoglobulin (TSI) levels and massive goitre may display discordant hypothyroxinemia with eutriiodothyroninemia or hypertriiodothyroninemia while on anti-thyroid drug therapy. A 25-year-old female with the above was started on oral carbimazole therapy for 9 months before total thyroidectomy. Preoperatively, her serum free T4 was reduced to below detection limit, and total T4 reduced to 11% of lower limit of normal, while T3 levels remained normal, and TSH remained largely suppressed. Immediately after total-thyroidectomy, a loading dose of L-thyroxine (L-T4) was administered intravenously. She was extubated without any postoperative complications. Serum free and total T4, and TSH normalized within the next 24 hours. The peculiar thyroid axis dynamics and use of L-T4 postoperative loading in such a rare clinical scenario are discussed.
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Abstract
More than a billion people worldwide are at risk of iodine deficiency (ID), with well-known consequences for development of the central nervous system. Furthermore, ID has also been associated with dyslipidemia and obesity in humans. To further understand the metabolic consequences of ID, here we kept 8-week-old C57/Bl6 mice at thermoneutrality (~28°C) while feeding them on a low iodine diet (LID). When compared with mice kept on control diet (LID + 0.71 μg/g iodine), the LID mice exhibited marked reduction in T4 and elevated plasma TSH, without changes in plasma T3 levels. LID mice grew normally, and had normal oxygen consumption, ambulatory activity, and heart expression of T3-responsive gene, confirming systemic euthyroidism. However, LID mice exhibited ~5% lower respiratory quotient (RQ), which reflected a ~2.3-fold higher contribution of fat to energy expenditure. LID mice also presented increased circulating levels of nonesterified fatty acids, ~60% smaller fat depots, and increased hepatic glycogen content, all indicative of accelerated lipolysis. LID mice responded much less to forced mobilization of energy substrates (50% food restriction for 3 days or starvation during 36 hours) because of limited size of the adipose depots. A 4-day treatment with T4 restored plasma T4 and TSH levels in LID mice and normalized RQ. We conclude that ID accelerates lipolysis and fatty acid oxidation, without affecting systemic thyroid hormone signaling. It is conceivable that the elevated plasma TSH levels trigger these changes by directly activating lipolysis in the adipose tissues.
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Affiliation(s)
| | | | - Tatiana L Fonseca
- Section of Endocrinology and Metabolism, University of Chicago, Chicago IL
| | - Antonio C Bianco
- Section of Endocrinology and Metabolism, University of Chicago, Chicago IL
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Villanger GD, Drover SSM, Nethery RC, Thomsen C, Sakhi AK, Øvergaard KR, Zeiner P, Hoppin JA, Reichborn-Kjennerud T, Aase H, Engel SM. Associations between urine phthalate metabolites and thyroid function in pregnant women and the influence of iodine status. Environ Int 2020; 137:105509. [PMID: 32044443 DOI: 10.1016/j.envint.2020.105509] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 01/17/2020] [Accepted: 01/17/2020] [Indexed: 05/23/2023]
Abstract
BACKGROUND Human populations, including susceptible subpopulations such as pregnant women and their fetuses, are continuously exposed to phthalates. Phthalates may affect the thyroid hormone system, causing concern for pregnancy health, birth outcomes and child development. Few studies have investigated the joint effect of phthalates on thyroid function in pregnant women, although they are present as a mixture with highly inter-correlated compounds. Additionally, no studies have investigated if the key nutrient for thyroid health, iodine, modifies these relationships. METHODS In this study, we examined the cross-sectional relationships between concentrations of 12 urinary phthalate metabolites and 6 plasma thyroid function biomarkers measured mid-pregnancy (~17 week gestation) in pregnant women (N = 1072), that were selected from a population-based prospective birth cohort, The Norwegian Mother, Father and Child Cohort study (MoBa). We investigated if the phthalate metabolite-thyroid function biomarker associations differed by iodine status by using a validated estimate of habitual dietary iodine intake based on a food frequency questionnaire from the 22nd gestation week. We accounted for the phthalate metabolite mixture by factor analyses, ultimately reducing the exposure into two uncorrelated factors. These factors were used as predictors in multivariable adjusted linear regression models with thyroid function biomarkers as the outcomes. RESULTS Factor 1, which included high loadings for mono-iso-butyl phthalate (MiBP), mono-n-butyl phthalate (MnBP), and monobenzyl phthalate (MBzP), was associated with increased total triiodothyronine (TT3) and free T3 index (fT3i). These associations appeared to be driven primarily by women with low iodine intake (<150 µg/day, ~70% of our sample). Iodine intake significantly modified (p-interaction < 0.05) the association of factor 1 with thyroid stimulating hormone (TSH), total thyroxine (TT4) and free T4 index (fT4i), such that only among women in the high iodine intake category (≥150 µg/day, i.e. sufficient) was this factor associated with increased TSH and decreased TT4 and FT4i, respectively. In contrast, factor 2, which included high loadings for di-2-ethylhexyl phthalate metabolites (∑DEHP) and di-iso-nonyl phthalate metabolites (∑DiNP), was associated with a decrease in TT3 and fT3i, which appeared fairly uniform across iodine intake categories. CONCLUSION We find that phthalate exposure is associated with thyroid function in mid-pregnancy among Norwegian women, and that iodine intake, which is essential for thyroid health, could influence some of these relationships.
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Affiliation(s)
- Gro D Villanger
- Norwegian Institute of Public Health, PO Box 222 Skøyen, N-0213 Oslo, Norway.
| | - Samantha S M Drover
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina and Chapel Hill, Chapel Hill, NC, USA
| | | | - Cathrine Thomsen
- Norwegian Institute of Public Health, PO Box 222 Skøyen, N-0213 Oslo, Norway
| | - Amrit K Sakhi
- Norwegian Institute of Public Health, PO Box 222 Skøyen, N-0213 Oslo, Norway
| | - Kristin R Øvergaard
- Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Pal Zeiner
- Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Jane A Hoppin
- Department of Biological Sciences, NC State University, Raleigh, NC, USA
| | - Ted Reichborn-Kjennerud
- Norwegian Institute of Public Health, PO Box 222 Skøyen, N-0213 Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Heidi Aase
- Norwegian Institute of Public Health, PO Box 222 Skøyen, N-0213 Oslo, Norway
| | - Stephanie M Engel
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina and Chapel Hill, Chapel Hill, NC, USA
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Seara F, Araujo I, Império G, Marassi M, Silva A, Mecawi A, Reis L, Olivares E. Propranolol inhibits myocardial infarction-induced brown adipose tissue D2 activation and maintains a low thyroid hormone state in rats. Braz J Med Biol Res 2019; 52:e8491. [PMID: 31618368 PMCID: PMC6787959 DOI: 10.1590/1414-431x20198491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 08/21/2019] [Indexed: 11/23/2022] Open
Abstract
Considering the recognized role of thyroid hormones on the cardiovascular system during health and disease, we hypothesized that type 2 deiodinase (D2) activity, the main activation pathway of thyroxine (T4)-to-triiodothyronine (T3), could be an important site to modulate thyroid hormone status, which would then constitute a possible target for β-adrenergic blocking agents in a myocardial infarction (MI) model induced by left coronary occlusion in rats. Despite a sustained and dramatic fall in serum T4 concentrations (60-70%), the serum T3 concentration fell only transiently in the first week post-infarction (53%) and returned to control levels at 8 and 12 weeks after surgery compared to the Sham group (P<0.05). Brown adipose tissue (BAT) D2 activity (fmol T4·min-1·mg ptn-1) was significantly increased by approximately 77% in the 8th week and approximately 100% in the 12th week in the MI group compared to that of the Sham group (P<0.05). Beta-blocker treatment (0.5 g/L propranolol given in the drinking water) maintained a low T3 state in MI animals, dampening both BAT D2 activity (44% reduction) and serum T3 (66% reduction in serum T3) compared to that of the non-treated MI group 12 weeks after surgery (P<0.05). Propranolol improved cardiac function (assessed by echocardiogram) in the MI group compared to the non-treated MI group by 40 and 57%, 1 and 12 weeks after treatment, respectively (P<0.05). Our data suggested that the beta-adrenergic pathway may contribute to BAT D2 hyperactivity and T3 normalization after MI in rats. Propranolol treatment maintained low T3 state and improved cardiac function additionally.
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Affiliation(s)
- F.A.C. Seara
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brasil
- Laboratório de Eletrofisiologia Cardíaca, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - I.G. Araujo
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brasil
- Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas, Sociedade Brasileira de Fisiologia, Programa Multicêntrico de Pós-Graduação em Ciências FisiológicasSociedade Brasileira de Fisiologia, Brasil
| | - G.E. Império
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brasil
| | - M.P. Marassi
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brasil
| | - A.C.M. Silva
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brasil
| | - A.S. Mecawi
- Departmento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil
| | - L.C. Reis
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brasil
- Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas, Sociedade Brasileira de Fisiologia, Programa Multicêntrico de Pós-Graduação em Ciências FisiológicasSociedade Brasileira de Fisiologia, Brasil
| | - E.L. Olivares
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brasil
- Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas, Sociedade Brasileira de Fisiologia, Programa Multicêntrico de Pós-Graduação em Ciências FisiológicasSociedade Brasileira de Fisiologia, Brasil
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Abstract
BACKGROUND This study aimed to establish the changes in the incidence and characteristics of iodine-induced hyperthyroidism (II-Hyper) and iodine-induced hypothyroidism (II-Hypo) in the two-year period before and the 10-year period after the increase in mandatory salt iodization from the previous 10 mg/kg of potassium iodide to 25 mg/kg in 1999. Furthermore, the aim was to determine the duration of treatment in II-Hyper patients, since no data regarding severity and treatment of II-Hyper with respect to iodine supply are available. METHODS This retrospective study reviewed medical records of 885 Slovenian patients first diagnosed with II-Hyper or II-Hypo between 1998 and 2009 at the Thyroid Department of the University Medical Centre Ljubljana. II-Hyper and II-Hypo were diagnosed by one out of 10 senior internal medicine specialists. The diagnosis was based on an adequate patient history, and laboratory measurements of thyrotropin, thyroid hormones, and thyroid antibodies. In most cases, thyroid ultrasound and thyroid scintigraphy were performed. Demographic characteristics and the type and the duration of treatment were also reviewed. RESULTS The incidence of II-Hypo was significantly higher after the increase in iodine supply than it was before (p < 0.001). After the increase in iodine supply, the incidence of II-Hyper was significantly lower than before the increase (p < 0.001). Furthermore, the portion of patients with overt hyperthyroidism decreased, predominantly due to the increased proportion of patients with subclinical hyperthyroidism (p = 0.007 and p = 0.015, respectively). The duration of treatment with antithyroid drugs and perchlorate was significantly shorter after the increase in iodine supply than it was before (p = 0.001 and p = 0.002, respectively). A significantly positive correlation between the year of the occurrence of excessive iodine intake (EII)-induced thyroid disease and the duration of treatment with amiodarone was found (R = 0.132; p = 0.048), suggesting that the longer the patients had an adequate iodine supply, the longer they could take amiodarone before EII-induced thyroid disorder developed. CONCLUSIONS After the increase in iodine supply, a higher incidence of II-Hypo and a lower incidence of II-Hyper were observed than before the increase. Less severe II-Hyper, shorter duration of treatment of II-Hyper, as well as a longer thyroid disease-free period in patients on amiodarone are additional beneficial clinical consequences after the establishment of an adequate iodine supply.
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Affiliation(s)
- Vid Bajuk
- 1 Faculty of Medicine, University of Ljubljana , Ljubljana, Slovenia
| | - Katja Zaletel
- 2 Department of Nuclear Medicine, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Edvard Pirnat
- 2 Department of Nuclear Medicine, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Sergej Hojker
- 1 Faculty of Medicine, University of Ljubljana , Ljubljana, Slovenia
- 2 Department of Nuclear Medicine, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Simona Gaberšček
- 1 Faculty of Medicine, University of Ljubljana , Ljubljana, Slovenia
- 2 Department of Nuclear Medicine, University Medical Centre Ljubljana , Ljubljana, Slovenia
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Craps J, Joris V, De Jongh B, Sonveaux P, Horman S, Lengelé B, Bertrand L, Many MC, Colin IM, Gérard AC. Involvement of mTOR and Regulation by AMPK in Early Iodine Deficiency-Induced Thyroid Microvascular Activation. Endocrinology 2016; 157:2545-59. [PMID: 27035650 DOI: 10.1210/en.2015-1911] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Iodine deficiency (ID) induces TSH-independent microvascular activation in the thyroid via the reactive oxygen species/nitric oxide-hypoxia-inducible factor-1α/vascular endothelial growth factor (VEGF) pathway. We hypothesized the additional involvement of mammalian target of rapamycin (mTOR) as a positive regulator of this pathway and AMP-activated protein kinase (AMPK) as a negative feedback regulator to explain the transient nature of ID-induced microvascular changes under nonmalignant conditions. mTOR and AMPK involvement was investigated using an in vitro model (human thyrocytes in primary cultures) and 2 murine models of goitrogenesis (normal NMRI and RET-PTC mice [a papillary thyroid cancer model]). In NMRI mice, ID had no effect on the phosphorylation of ribosomal S6 kinase (p70S6K), a downstream target of mTOR. However, rapamycin inhibited ID-induced thyroid blood flow and VEGF protein expression. In the RET-PTC model, ID strongly increased the phosphorylation of p70S6K, whereas rapamycin completely inhibited the ID-induced increase in p70S6K phosphorylation, thyroid blood flow, and VEGF-A expression. In vitro, although ID increased p70S6K phosphorylation, the ID-stimulated hypoxia-inducible factor/VEGF pathway was inhibited by rapamycin. Activation of AMPK by metformin inhibited ID effects both in vivo and in vitro. In AMPK-α1 knockout mice, the ID-induced increase in thyroid blood flow and VEGF-A protein expression persisted throughout the treatment, whereas both parameters returned to control values in wild-type mice after 4 days of ID. In conclusion, mTOR is required for early ID-induced thyroid microvascular activation. AMPK negatively regulates this pathway, which may account for the transient nature of ID-induced TSH-independent vascular effects under benign conditions.
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Affiliation(s)
- J Craps
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
| | - V Joris
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
| | - B De Jongh
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
| | - P Sonveaux
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
| | - S Horman
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
| | - B Lengelé
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
| | - L Bertrand
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
| | - M-C Many
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
| | - I M Colin
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
| | - A-C Gérard
- Pôle de Morphologie (J.C., B.D.J., B.L., M.-C.M., I.M.C., A.-C.G.), de Pharmacologie et Thérapeutique (V.J., P.S.), de Recherche Cardiovasculaire (S.H., L.B.), Institut de Recherche Expérimentale et Clinique, Laboratoire de Biologie Cellulaire, and Institut des Sciences de la Vie (A.-C.G.), Université Catholique de Louvain, Louvain-La-Neuve, Brussels 1200, Belgium
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Donzelli R, Colligiani D, Kusmic C, Sabatini M, Lorenzini L, Accorroni A, Nannipieri M, Saba A, Iervasi G, Zucchi R. Effect of Hypothyroidism and Hyperthyroidism on Tissue Thyroid Hormone Concentrations in Rat. Eur Thyroid J 2016; 5:27-34. [PMID: 27099836 PMCID: PMC4836127 DOI: 10.1159/000443523] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/17/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND OBJECTIVE The present study was aimed at determining the effects of experimental hypothyroidism and hyperthyroidism on tissue thyroid hormones by a mass spectrometry-based technique. METHODS Rats were subjected to propylthiouracil treatment or administration of exogenous triiodothyronine (T3) or thyroxine (T4). Tissue T3 and T4 were measured by liquid chromatography tandem mass spectrometry in the heart, liver, kidney, visceral and subcutaneous adipose tissue, and brain. RESULTS Baseline tissue T3 and T4 concentrations ranged from 0.2 to 20 pmol ∙ g(-1) and from 3 to 125 pmol ∙ g(-1), respectively, with the highest values in the liver and kidney, and the lowest values in the adipose tissue. The T3/T4 ratio (expressed as a percentage) was in the 7-20% range in all tissues except the brain, where it averaged 75%. In hypothyroidism, tissue T3 was more severely reduced than serum free T3, averaging 1-6% of the baseline versus 30% of the baseline. The extent of tissue T3 reduction, expressed as percentage of the baseline, was not homogeneous (p < 0.001), with liver = kidney > brain > heart > adipose tissue. The tissue T3/T4 ratio significantly increased in all organs except the kidney, averaging 330% in the brain and 50-90% in the other tissues. By contrast, exogenous T3 and T4 administration produced similar increases in serum free T3 and in tissue T3, and the relative changes were not significantly different between different tissues. CONCLUSIONS While the response to increased thyroid hormones availability was similar in all tissues, decreased thyroid hormone availability induced compensatory responses, leading to a significant mismatch between changes in serum and in specific tissues.
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Affiliation(s)
| | - Daria Colligiani
- Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | | | | | | | - Alice Accorroni
- Departments of Pathology, University of Pisa, Pisa, Italy
- Scuola Superiore Sant'Anna, Pisa, Italy
| | | | | | | | - Riccardo Zucchi
- Departments of Pathology, University of Pisa, Pisa, Italy
- *Riccardo Zucchi, MD, PhD, Laboratory of Biochemistry, Department of Pathology, University of Pisa, via Roma 55, IT-56126 Pisa (Italy), E-Mail
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Wei W, Wang Y, Dong J, Wang Y, Min H, Song B, Shan Z, Teng W, Xi Q, Chen J. Hypothyroxinemia induced by maternal mild iodine deficiency impairs hippocampal myelinated growth in lactational rats. Environ Toxicol 2015; 30:1264-1274. [PMID: 24753110 DOI: 10.1002/tox.21997] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 04/01/2014] [Accepted: 04/04/2014] [Indexed: 06/03/2023]
Abstract
Hypothyroxinemia induced by maternal mild iodine deficiency causes neurological deficits and impairments of brain function in offspring. Hypothyroxinemia is prevalent in developing and developed countries alike. However, the mechanism underlying these deficits remains less well known. Given that the myelin plays an important role in learning and memory function, we hypothesize that hippocampal myelinated growth may be impaired in rat offspring exposed to hypothyroxinemia induced by maternal mild iodine deficiency. To test this hypothesis, the female Wistar rats were used and four experimental groups were prepared: (1) control; (2) maternal mild iodine deficiency diet inducing hypothyroxinemia; (3) hypothyroidism induced by maternal severe iodine deficiency diet; (4) hypothyroidism induced by maternal methimazole water. The rats were fed the diet from 3 months before pregnancy to the end of lactation. Our results showed that the physiological changes occuring in the hippocampal myelin were altered in the mild iodine deficiency group as indicated by the results of immunofluorescence of myelin basic proteins on postnatal day 14 and postnatal day 21. Moreover, hypothyroxinemia reduced the expressions of oligodendrocyte lineage transcription factor 2 and myelin-related proteins in the treatments on postnatal day 14 and postnatal day 21. Our data suggested that hypothyroxinemia induced by maternal mild iodine deficiency may impair myelinated growth of the offspring.
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Affiliation(s)
- Wei Wei
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Jing Dong
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Yuan Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Hui Min
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Binbin Song
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
| | - Zhongyan Shan
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Weiping Teng
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Qi Xi
- Department of Physiology, the University of Tennessee Health Science Center, Memphis, Tennessee, 38163, USA
| | - Jie Chen
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
- Department of Endocrinology and Metabolism and Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang, People's Republic of China
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11
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Min H, Dong J, Wang Y, Wang Y, Teng W, Xi Q, Chen J. Maternal Hypothyroxinemia-Induced Neurodevelopmental Impairments in the Progeny. Mol Neurobiol 2015; 53:1613-1624. [PMID: 25666160 DOI: 10.1007/s12035-015-9101-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/15/2015] [Indexed: 12/16/2022]
Abstract
Maternal hypothyroxinemia can induce neurodevelopmental impairments in the developing fetus. We here review recent studies on the epidemiology and molecular mechanisms associated with this important public health issue. In 2011, the American Thyroid Association defined maternal hypothyroxinemia as low serum free thyroxine (FT4) levels (<5th or <10th percentile) existing in conjunction with normal serum free triiodothyronine (FT3) or thyroid stimulating hormone (TSH) levels during pregnancy. Compared to clinical or subclinical hypothyroidism, hypothyroxinemia is more commonly found in pregnant women. Hypothyroxinemia usually ensues in response to several factors, such as mild iodine deficiency, environmental endocrine disrupters, or certain thyroid diseases. Unequivocal evidence demonstrates that maternal hypothyroxinemia leads to negative effects on fetal brain development, increasing the risks for cognitive deficits and poor psychomotor development in resulting progeny. In support of this, rodent models provide direct evidence of neurodevelopmental damage induced by maternal hypothyroxinemia, including dendritic and axonal growth limitation, neural abnormal location, and synaptic function alteration. The neurodevelopmental impairments induced by hypothyroxinemia suggest an independent role of T4. Increasing evidence indicates that adequate thyroxine is required for the mothers in order to protect against the abnormal brain development in their progeny.
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Affiliation(s)
- Hui Min
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110013, People's Republic of China
- Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Jing Dong
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110013, People's Republic of China
- Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110013, People's Republic of China
- Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Yuan Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110013, People's Republic of China
- Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Weiping Teng
- Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Qi Xi
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, TN, 38163, USA.
| | - Jie Chen
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110013, People's Republic of China.
- Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University, Shenyang, People's Republic of China.
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12
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Craps J, Wilvers C, Joris V, De Jongh B, Vanderstraeten J, Lobysheva I, Balligand JL, Sonveaux P, Gilon P, Many MC, Gérard AC, Colin IM. Involvement of nitric oxide in iodine deficiency-induced microvascular remodeling in the thyroid gland: role of nitric oxide synthase 3 and ryanodine receptors. Endocrinology 2015; 156:707-20. [PMID: 25406019 DOI: 10.1210/en.2014-1729] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Iodine deficiency (ID) induces microvascular changes in the thyroid gland via a TSH-independent reactive oxygen species-hypoxia inducible factor (HIF)-1α-vascular endothelial growth factor (VEGF) pathway. The involvement of nitric oxide (NO) in this pathway and the role of calcium (Ca(2+)) and of ryanodine receptors (RYRs) in NO synthase 3 (NOS3) activation were investigated in a murine model of goitrogenesis and in 3 in vitro models of ID, including primary cultures of human thyrocytes. ID activated NOS3 and the production of NO in thyrocytes in vitro and increased the thyroid blood flow in vivo. Using bevacizumab (a blocking antibody against VEGF-A) in mice, it appeared that NOS3 is activated upstream of VEGF-A. L-nitroarginine methyl ester (a NOS inhibitor) blocked the ID-induced increase in thyroid blood flow in vivo and NO production in vitro, as well as ID-induced VEGF-A mRNA and HIF-1α expression in vitro, whereas S-nitroso-acetyl-penicillamine (a NO donor) did the opposite. Ca(2+) is involved in this pathway as intracellular Ca(2+) flux increased after ID, and thapsigargin activated NOS3 and increased VEGF-A mRNA expression. Two of the 3 known mammalian RYR isoforms (RYR1 and RYR2) were shown to be expressed in thyrocytes. RYR inhibition using ryanodine at 10μM decreased ID-induced NOS3 activation, HIF-1α, and VEGF-A expression, whereas RYR activation with ryanodine at 1nM increased NOS3 activation and VEGF-A mRNA expression. In conclusion, during the early phase of TSH-independent ID-induced microvascular activation, ID sequentially activates RYRs and NOS3, thereby supporting ID-induced activation of the NO/HIF-1α/VEGF-A pathway in thyrocytes.
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Affiliation(s)
- J Craps
- Pôle de Morphologie (J.C., C.W., B.D.J., J.V., M.-C.M., I.M.C.), de Pharmacologie et Thérapeutique (V.J., I.L., J.-L.B., P.S.), et d'Endocrinologie, Diabète et Nutrition (P.G.), Institut de Recherche Expérimentale et Clinique, Secteur des Sciences de la Santé, Faculté de Médecine, Université catholique de Louvain, 1200, Brussels, Belgium; and Service d'Endocrino-Diabétologie (A.-C.G., I.M.C.), Centre Hospitalier Régional, 7000, Mons-Hainaut, Belgium
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Jonklaas J, Bianco AC, Bauer AJ, Burman KD, Cappola AR, Celi FS, Cooper DS, Kim BW, Peeters RP, Rosenthal MS, Sawka AM. Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement. Thyroid 2014; 24:1670-751. [PMID: 25266247 PMCID: PMC4267409 DOI: 10.1089/thy.2014.0028] [Citation(s) in RCA: 928] [Impact Index Per Article: 92.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND A number of recent advances in our understanding of thyroid physiology may shed light on why some patients feel unwell while taking levothyroxine monotherapy. The purpose of this task force was to review the goals of levothyroxine therapy, the optimal prescription of conventional levothyroxine therapy, the sources of dissatisfaction with levothyroxine therapy, the evidence on treatment alternatives, and the relevant knowledge gaps. We wished to determine whether there are sufficient new data generated by well-designed studies to provide reason to pursue such therapies and change the current standard of care. This document is intended to inform clinical decision-making on thyroid hormone replacement therapy; it is not a replacement for individualized clinical judgment. METHODS Task force members identified 24 questions relevant to the treatment of hypothyroidism. The clinical literature relating to each question was then reviewed. Clinical reviews were supplemented, when relevant, with related mechanistic and bench research literature reviews, performed by our team of translational scientists. Ethics reviews were provided, when relevant, by a bioethicist. The responses to questions were formatted, when possible, in the form of a formal clinical recommendation statement. When responses were not suitable for a formal clinical recommendation, a summary response statement without a formal clinical recommendation was developed. For clinical recommendations, the supporting evidence was appraised, and the strength of each clinical recommendation was assessed, using the American College of Physicians system. The final document was organized so that each topic is introduced with a question, followed by a formal clinical recommendation. Stakeholder input was received at a national meeting, with some subsequent refinement of the clinical questions addressed in the document. Consensus was achieved for all recommendations by the task force. RESULTS We reviewed the following therapeutic categories: (i) levothyroxine therapy, (ii) non-levothyroxine-based thyroid hormone therapies, and (iii) use of thyroid hormone analogs. The second category included thyroid extracts, synthetic combination therapy, triiodothyronine therapy, and compounded thyroid hormones. CONCLUSIONS We concluded that levothyroxine should remain the standard of care for treating hypothyroidism. We found no consistently strong evidence for the superiority of alternative preparations (e.g., levothyroxine-liothyronine combination therapy, or thyroid extract therapy, or others) over monotherapy with levothyroxine, in improving health outcomes. Some examples of future research needs include the development of superior biomarkers of euthyroidism to supplement thyrotropin measurements, mechanistic research on serum triiodothyronine levels (including effects of age and disease status, relationship with tissue concentrations, as well as potential therapeutic targeting), and long-term outcome clinical trials testing combination therapy or thyroid extracts (including subgroup effects). Additional research is also needed to develop thyroid hormone analogs with a favorable benefit to risk profile.
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Affiliation(s)
| | - Antonio C. Bianco
- Division of Endocrinology, Rush University Medical Center, Chicago, Illinois
| | - Andrew J. Bauer
- Division of Endocrinology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Kenneth D. Burman
- Endocrine Section, Medstar Washington Hospital Center, Washington, DC
| | - Anne R. Cappola
- Division of Endocrinology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Francesco S. Celi
- Division of Endocrinology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - David S. Cooper
- Division of Endocrinology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Brian W. Kim
- Division of Endocrinology, Rush University Medical Center, Chicago, Illinois
| | - Robin P. Peeters
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - M. Sara Rosenthal
- Program for Bioethics, Department of Internal Medicine, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Anna M. Sawka
- Division of Endocrinology, University Health Network and University of Toronto, Toronto, Ontario, Canada
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Hu X, Teng X, Zheng H, Shan Z, Li J, Jin T, Xiong C, Zhang H, Fan C, Teng W. Iron deficiency without anemia causes maternal hypothyroxinemia in pregnant rats. Nutr Res 2014; 34:604-12. [PMID: 25150119 DOI: 10.1016/j.nutres.2014.06.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 04/19/2014] [Accepted: 06/09/2014] [Indexed: 10/25/2022]
Abstract
Because of increased total red blood cell mass and the demands of the fetus, iron requirements are greater during pregnancy than at most other times. Previous experiments in nonpregnant women have shown that iron deficiency (ID) can reduce circulating thyroxine and triiodothyronine levels; therefore, we hypothesized that ID before pregnancy can reduce thyroid hormone levels in maternal circulation and in the thyroid gland during pregnancy. In the present study, 2 types of rat models with ID were established using diets with different iron concentrations. Levels of thyroid hormone, hemoglobin, serum iron, liver iron, serum ferritin, serum transferrin receptor, and serum thyroid-stimulating hormone as well as thyroid peroxidase activity were measured throughout pregnancy, and thyroid structure was analyzed. Both mild ID with anemia and ID without anemia resulted in maternal hypothyroxinemia from midgestation to the end of the pregnancy. Thyroid peroxidase activity significantly decreased, even before the reduction of liver iron concentrations in ID groups. Iron deficiency reduced the size of follicular cavities but did not destroy the follicular structure. Linear regressions were performed to compare total levels of maternal serum thyroxine to indices of iron status for individual dams. This is the first rat study to report our results stating that ID can cause maternal hypothyroxinemia during early pregnancy.
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Affiliation(s)
- Xiaona Hu
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Xiaochun Teng
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China.
| | - Hongzhi Zheng
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Zhongyan Shan
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Jing Li
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Ting Jin
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Chuhui Xiong
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Hongmei Zhang
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Chenling Fan
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Weiping Teng
- Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine Disease, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China.
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15
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Iglesias A, García-Nimo L, Cocho de Juan JA, Moreno JC. Towards the pre-clinical diagnosis of hypothyroidism caused by iodotyrosine deiodinase (DEHAL1) defects. Best Pract Res Clin Endocrinol Metab 2014; 28:151-9. [PMID: 24629858 DOI: 10.1016/j.beem.2013.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
DEHAL1 (also named IYD) is the thyroidal enzyme that deiodinates mono- and diiodotyrosines (MIT, DIT) and recycles iodine, a scarce element in the environment, for the efficient synthesis of thyroid hormone. Failure of this enzyme leads to the iodotyrosine deiodinase deficiency (ITDD), characterized by hypothyroidism, compressive goiter and variable mental retardation, whose diagnostic hallmark is the elevation of iodotyrosines in serum and urine. However, the specific diagnosis of this type of hypothyroidism is not routinely performed, due to technical and practical difficulties in iodotyrosine determinations. A handful of mutations in the DEHAL1 gene have been identified as the molecular basis for the ITDD. Patients harboring DEHAL1 defects so far described all belong to consanguineous families, and psychomotor deficits were present in some affected individuals. This is probably due to the lack of biochemical expression of the disease at the beginning of life, which causes ITDD being undetected in screening programs for congenital hypothyroidism, as currently performed. This worrying feature calls for efforts to improve pre-clinical detection of iodotyrosine deiodinase deficiency during the neonatal time. Such a challenge poses questions of patho-physiological (natural history of the disease, environmental factors influencing its expression) epidemiological (prevalence of ITDD) and technical nature (development of optimal methodology for safe detection of pre-clinical ITDD), which will be addressed in this review.
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Affiliation(s)
- Ainhoa Iglesias
- Molecular Thyroid Laboratory, Institute for Medical and Molecular Genetics (INGEMM), La Paz University Hospital, Madrid, Spain
| | - Laura García-Nimo
- Laboratory of Metabolic Disorders, Santiago de Compostela University Hospital, Santiago, Spain
| | - José A Cocho de Juan
- Laboratory of Metabolic Disorders, Santiago de Compostela University Hospital, Santiago, Spain
| | - José C Moreno
- Molecular Thyroid Laboratory, Institute for Medical and Molecular Genetics (INGEMM), La Paz University Hospital, Madrid, Spain.
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16
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Wang Y, Wei W, Song B, Wang Y, Dong J, Min H, Chen J. Developmental hypothyroxinemia caused by mild iodine deficiency leads to HFS-induced LTD in rat hippocampal CA1 region: involvement of AMPA receptor. Mol Neurobiol 2014; 50:348-57. [PMID: 24532248 DOI: 10.1007/s12035-014-8656-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 01/29/2014] [Indexed: 11/27/2022]
Abstract
Hypothyroidism induced by severe iodine deficiency (ID) during developmental period seriously damages the central nervous system function. In addition to developmental hypothyroidism induced by severe ID, developmental hypothyroxinemia induced by mild ID is potentially damaging for neurodevelopment and learning and memory in children. Wistar rats were treated with iodine-deficient diet or methimazole (MMZ) during pregnancy and lactation to induce developmental hypothyroxinemia or hypothyroidism in the present study. Pups were weaned on postnatal day (PN) 21 and used for electrophysiological recordings on PN80. It is generally accepted that long-term depression (LTD) is induced at low-frequency stimulation (LFS) in hippocampal CA1 region. Surprisingly, we observed developmental hypothyroxinemia as well as developmental hypothyroidism led to high-frequency stimulation (HFS)-induced LTD in hippocampal CA1 region. The abnormal HFS-induced LTD suggests not only developmental hypothyroidism but also developmental hypothyroxinemia impairs learning and memory. To explore the mechanisms responsible for the HFS-induced LTD, the phosphorylation status of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) was investigated. The results showed that developmental hypothyroxinemia as well as developmental hypothyroidism decreased the phosphorylation of AMPAR subunit glutamate receptor 1 (GluR1) at serine 831 and serine 845 in hippocampal CA1 region. Neither developmental hypothyroxinemia nor developmental hypothyroidism altered the phosphorylation of AMPAR subunit glutamate receptor 2 (GluR2) at serine 880. Increased levels of protein phosphatase-1 (PP1) were also observed in hippocampal CA1 regions of pups subjected to developmental hypothyroxinemia or hypothyroidism. Taken together, our results suggest that the increased levels of PP1 caused by developmental hypothyroxinemia or hypothyroidism may account for the dephosphorylation of GluR1 at serine 831 and serine 845, which may contribute to HFS-induced LTD in hippocampal CA1 region.
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Affiliation(s)
- Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang, 110001, People's Republic of China
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17
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Selmi-Ruby S, Bouazza L, Obregon MJ, Conscience A, Flamant F, Samarut J, Borson-Chazot F, Rousset B. The targeted inactivation of TRβ gene in thyroid follicular cells suggests a new mechanism of regulation of thyroid hormone production. Endocrinology 2014; 155:635-46. [PMID: 24265449 DOI: 10.1210/en.2013-1435] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Thyroid epithelial cells, or thyrocytes, express functional thyroid hormone receptors but no precise role has yet been assigned to either TRα or TRβ in the thyroid gland. In this study, we analyzed the impact of inactivating the TRβ gene in the thyroid of mice. First, we generated a mouse line named Thyr-Cre, expressing the Cre recombinase under the control of the thyroglobulin gene promoter, which led to a complete recombination of floxed genes in thyrocytes. Thyr-Cre mice were then crossed with TRβ floxed mice (TRβ(flox/flox)) to obtain a thyrocyte-selective deletion of TRβ. Thyr-TRβ(-/-) mice were characterized by a decrease in the size and functional activity of the thyroid gland. These alterations were associated with a decrease in plasma TSH concentration. Surprisingly, Thyr-TRβ(-/-) displayed elevated serum T(4) and rT(3) concentrations with no significant change in serum T(3) levels. Their intrathyroidal free T(4) and rT(3) contents were also elevated, whereas the ratio of serum T(4) to thyroid free T(4) was decreased by comparison with wild-type littermates. Also, within the thyroid, deiodinases D1 and D2 were reduced as well as the expression levels of genes encoding monocarboxylate transporters (Mct8 and Mct10). Such a decrease in intrathyroidal deiodination of T(4) and in the expression of genes encoding thyroid hormone transporters may contribute to the primary overproduction of T(4) observed in Thyr-TRβ(-/-) mice. In conclusion, these data show that the control of thyroid hormone production involves not only TRβ-dependent mechanisms acting at the level of hypothalamus and pituitary but also TRβ-dependent mechanisms acting at the thyroid level.
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Affiliation(s)
- Samia Selmi-Ruby
- Inserm Unité 1052 (S.S.-R., F.B.-C., B.R.), Lyon, France; Centre National de la Recherche Scientifique Unité Mixte de Recherche 5286 (S.S.-R., F.B.-C., B.R.), Lyon, France; Université Claude Bernard Lyon 1 (S.S.-R., L.B., F.B.-C., B.R.), Faculté de Médecine Lyon-Est-Site Laennec, Lyon Cedex 08, F-69372 France; Instituto de Investigaciones Biomedicas (Consejo Superior de Investigaciones Científicas-Universidad Autonoma Madrid) (M.-J.O.), Madrid, M-28029 Spain; and Institut de Génomique Fonctionnelle de Lyon (A.C., F.F., J.S.), Lyon, F-69007 France
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Abstract
The Na(+)/I(-) symporter (NIS) is the plasma membrane glycoprotein that mediates active I(-) transport in the thyroid and other tissues, such as salivary glands, stomach, lactating breast, and small intestine. In the thyroid, NIS-mediated I(-) uptake plays a key role as the first step in the biosynthesis of the thyroid hormones, of which iodine is an essential constituent. These hormones are crucial for the development of the central nervous system and the lungs in the fetus and the newborn and for intermediary metabolism at all ages. Since the cloning of NIS in 1996, NIS research has become a major field of inquiry, with considerable impact on many basic and translational areas. In this article, we review the most recent findings on NIS, I(-) homeostasis, and related topics and place them in historical context. Among many other issues, we discuss the current outlook on iodide deficiency disorders, the present stage of understanding of the structure/function properties of NIS, information gleaned from the characterization of I(-) transport deficiency-causing NIS mutations, insights derived from the newly reported crystal structures of prokaryotic transporters and 3-dimensional homology modeling, and the novel discovery that NIS transports different substrates with different stoichiometries. A review of NIS regulatory mechanisms is provided, including a newly discovered one involving a K(+) channel that is required for NIS function in the thyroid. We also cover current and potential clinical applications of NIS, such as its central role in the treatment of thyroid cancer, its promising use as a reporter gene in imaging and diagnostic procedures, and the latest studies on NIS gene transfer aimed at extending radioiodide treatment to extrathyroidal cancers, including those involving specially engineered NIS molecules.
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Affiliation(s)
- Carla Portulano
- Department of Molecular and Cellular Physiology (C.P., N.C.), Yale University School of Medicine, New Haven, Connecticut 06510; and Department of Molecular Pharmacology (M.P.-B.), Albert Einstein College of Medicine, Bronx, New York 10469
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19
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Bianco AC, Anderson G, Forrest D, Galton VA, Gereben B, Kim BW, Kopp PA, Liao XH, Obregon MJ, Peeters RP, Refetoff S, Sharlin DS, Simonides WS, Weiss RE, Williams GR. American Thyroid Association Guide to investigating thyroid hormone economy and action in rodent and cell models. Thyroid 2014; 24:88-168. [PMID: 24001133 PMCID: PMC3887458 DOI: 10.1089/thy.2013.0109] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND An in-depth understanding of the fundamental principles that regulate thyroid hormone homeostasis is critical for the development of new diagnostic and treatment approaches for patients with thyroid disease. SUMMARY Important clinical practices in use today for the treatment of patients with hypothyroidism, hyperthyroidism, or thyroid cancer are the result of laboratory discoveries made by scientists investigating the most basic aspects of thyroid structure and molecular biology. In this document, a panel of experts commissioned by the American Thyroid Association makes a series of recommendations related to the study of thyroid hormone economy and action. These recommendations are intended to promote standardization of study design, which should in turn increase the comparability and reproducibility of experimental findings. CONCLUSIONS It is expected that adherence to these recommendations by investigators in the field will facilitate progress towards a better understanding of the thyroid gland and thyroid hormone dependent processes.
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Affiliation(s)
- Antonio C. Bianco
- Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine, Miami, Florida
| | - Grant Anderson
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota Duluth, Duluth, Minnesota
| | - Douglas Forrest
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Valerie Anne Galton
- Department of Physiology and Neurobiology, Dartmouth Medical School, Lebanon, New Hampshire
| | - Balázs Gereben
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Brian W. Kim
- Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine, Miami, Florida
| | - Peter A. Kopp
- Division of Endocrinology, Metabolism, and Molecular Medicine, and Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Xiao Hui Liao
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, The University of Chicago, Chicago, Illinois
| | - Maria Jesus Obregon
- Institute of Biomedical Investigation (IIB), Spanish National Research Council (CSIC) and Autonomous University of Madrid, Madrid, Spain
| | - Robin P. Peeters
- Division of Endocrinology, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Samuel Refetoff
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, The University of Chicago, Chicago, Illinois
| | - David S. Sharlin
- Department of Biological Sciences, Minnesota State University, Mankato, Minnesota
| | - Warner S. Simonides
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Roy E. Weiss
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, The University of Chicago, Chicago, Illinois
| | - Graham R. Williams
- Department of Medicine, Imperial College London, Hammersmith Campus, London, United Kingdom
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Wang Y, Wang Y, Dong J, Wei W, Song B, Min H, Yu Y, Lei X, Zhao M, Teng W, Chen J. Developmental hypothyroxinemia and hypothyroidism reduce proliferation of cerebellar granule neuron precursors in rat offspring by downregulation of the sonic hedgehog signaling pathway. Mol Neurobiol 2013; 49:1143-52. [PMID: 24264724 DOI: 10.1007/s12035-013-8587-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/05/2013] [Indexed: 01/19/2023]
Abstract
Iodine deficiency (ID)-induced hypothyroxinemia and hypothyroidism during development result in dysfunction of the central nervous system, affecting psychomotor and motor function, although the underlying mechanisms causing these alterations are still unclear. Therefore, our aim is to study the effects of developmental hypothyroxinemia, caused by mild ID, and developmental hypothyroidism, caused by severe ID or methimazole (MMZ), on the proliferation of cerebellar granule neuron precursors (CGNPs), an excellent experimental model of cerebellar development and function. The sonic hedgehog (Shh) signaling pathway is essential for CGNP proliferation, and as such, its activation is also investigated here. A maternal hypothyroxinemia model was established in Wistar rats by administrating a mild ID diet, and two maternal hypothyroidism models were developed either by administrating a severe ID diet or MMZ water. Our results showed that hypothyroxinemia and hypothyroidism reduced proliferation of CGNPs on postnatal day (PN) 7, PN14, and PN21. Accordingly, the mean intensity of proliferating cell nuclear antigen and Ki67 nuclear antigen immunofluorescence was reduced in the mild ID, severe ID, and MMZ groups. Moreover, maternal hypothyroxinemia and hypothyroidism reduced expression of the Shh signaling pathway on PN7, PN14, and PN21. Our study supports the hypothesis that developmental hypothyroxinemia induced by mild ID, and hypothyroidism induced by severe ID or MMZ, reduce the proliferation of CGNPs, which may be ascribed to the downregulation of the Shh signaling pathway.
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Affiliation(s)
- Yuan Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang, 110001, People's Republic of China
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Wei W, Wang Y, Wang Y, Dong J, Min H, Song B, Teng W, Xi Q, Chen J. Developmental hypothyroxinaemia induced by maternal mild iodine deficiency delays hippocampal axonal growth in the rat offspring. J Neuroendocrinol 2013; 25:852-62. [PMID: 23763342 DOI: 10.1111/jne.12058] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 05/29/2013] [Accepted: 06/09/2013] [Indexed: 12/27/2022]
Abstract
Iodine is essential for the biosynthesis of thyroid hormones, including triiodothyronine and thyroxine. Thyroid hormones are important for central nervous system development. Mild maternal iodine deficiency (ID)-induced hypothyroxinaemia causes neurological deficits and mental retardation of the foetus. However, the detailed mechanism underlying these deficits is still largely unknown. Given that the growth-associated protein of 43 kDa (GAP-43), semaphorin 3A (Sema3A) and the glycogen synthase kinase 3β (GSK3β)/collapsin response mediator protein 2 (CRMP2) pathway are essential for axonal development, we hypothesise that hippocampal axonal growth-related proteins may be impaired, which may contribute to hippocampal axonal growth delay in rat offspring exposed to maternal hypothyroxinaemia. To test this hypothesis, maternal hypothyroxinaemia models were established in Wistar rats using a mild ID diet. Besides a negative control group, two maternal hypothyroidism models were created with either a severe ID diet or methimazole in the water. Our results showed that maternal hypothyroxinaemia exposure delayed offspring axonal growth on gestational day 19, postnatal day (PN) 7, PN14 and PN21. Consistent with this, the mean intensity of hippocampal CRMP2 and Tau1 immunofluorescence axonal protein was reduced in the mild ID group. Moreover, maternal hypothyroxinaemia disrupted expressions of GAP-43 and Sema3A. Furthermore, the phosphorylation of GSK3β and CRMP2 was also affected in the treated offspring, implying a potential mechanism by which hypothyroxinaemia-exposure affects neurodevelopment. Taken together, our data support the hypothesis that maternal hypothyroxinaemia may impair axonal growth of the offspring.
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Affiliation(s)
- W Wei
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
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22
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Wei W, Wang Y, Dong J, Wang Y, Min H, Song B, Shan Z, Teng W, Xi Q, Chen J. Hypothyroxinemia induced by mild iodine deficiency deregulats thyroid proteins during gestation and lactation in dams. Int J Environ Res Public Health 2013; 10:3233-45. [PMID: 23917811 PMCID: PMC3774435 DOI: 10.3390/ijerph10083233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 07/24/2013] [Accepted: 07/26/2013] [Indexed: 11/17/2022]
Abstract
The main object of the present study was to explore the effect on thyroidal proteins following mild iodine deficiency (ID)-induced maternal hypothyroxinemia during pregnancy and lactation. In the present study, we established a maternal hypothyroxinemia model in female Wistar rats by using a mild ID diet. Maternal thyroid iodine content and thyroid weight were measured. Expressions of thyroid-associated proteins were analyzed. The results showed that the mild ID diet increased thyroid weight, decreased thyroid iodine content and increased expressions of thyroid transcription factor 1, paired box gene 8 and Na+/I- symporter on gestational day (GD) 19 and postpartum days (PN) 21 in the maternal thyroid. Moreover, the up-regulated expressions of type 1 iodothyronine deiodinase (DIO1) and type 2 iodothyronine deiodinase (DIO2) were detected in the mild ID group on GD19 and PN21. Taken together, our data indicates that during pregnancy and lactation, a maternal mild ID could induce hypothyroxinemia and increase the thyroidal DIO1 and DIO2 levels.
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Affiliation(s)
- Wei Wei
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang 110001, China; E-Mails: (W.W.); (Y.W.); (J.D.); (Y.W.); (H.M.); (B.S.); (Q.X.)
- Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang 110001, China; E-Mails: (Z.S.); (W.T.)
| | - Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang 110001, China; E-Mails: (W.W.); (Y.W.); (J.D.); (Y.W.); (H.M.); (B.S.); (Q.X.)
- Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang 110001, China; E-Mails: (Z.S.); (W.T.)
| | - Jing Dong
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang 110001, China; E-Mails: (W.W.); (Y.W.); (J.D.); (Y.W.); (H.M.); (B.S.); (Q.X.)
- Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang 110001, China; E-Mails: (Z.S.); (W.T.)
| | - Yuan Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang 110001, China; E-Mails: (W.W.); (Y.W.); (J.D.); (Y.W.); (H.M.); (B.S.); (Q.X.)
| | - Hui Min
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang 110001, China; E-Mails: (W.W.); (Y.W.); (J.D.); (Y.W.); (H.M.); (B.S.); (Q.X.)
| | - Binbin Song
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang 110001, China; E-Mails: (W.W.); (Y.W.); (J.D.); (Y.W.); (H.M.); (B.S.); (Q.X.)
| | - Zhongyan Shan
- Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang 110001, China; E-Mails: (Z.S.); (W.T.)
| | - Weiping Teng
- Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang 110001, China; E-Mails: (Z.S.); (W.T.)
| | - Qi Xi
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang 110001, China; E-Mails: (W.W.); (Y.W.); (J.D.); (Y.W.); (H.M.); (B.S.); (Q.X.)
- Department of Physiology, the University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Jie Chen
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, 92 North 2nd Road, Shenyang 110001, China; E-Mails: (W.W.); (Y.W.); (J.D.); (Y.W.); (H.M.); (B.S.); (Q.X.)
- Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang 110001, China; E-Mails: (Z.S.); (W.T.)
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Wang Y, Wei W, Wang Y, Dong J, Song B, Min H, Teng W, Chen J. Neurotoxicity of developmental hypothyroxinemia and hypothyroidism in rats: Impairments of long-term potentiation are mediated by phosphatidylinositol 3-kinase signaling pathway. Toxicol Appl Pharmacol 2013; 271:257-65. [PMID: 23707767 DOI: 10.1016/j.taap.2013.04.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 04/24/2013] [Accepted: 04/29/2013] [Indexed: 12/15/2022]
Abstract
Neurotoxicity of iodine deficiency-induced hypothyroidism during developmental period results in serious impairments of brain function, such as learning and memory. These impairments are largely irreversible, and the underlying mechanisms remain unclear. In addition to hypothyroidism, iodine deficiency may cause hypothyroxinemia, a relatively subtle form of thyroid hormone deficiency. Neurotoxicity of developmental hypothyroxinemia also potentially impairs learning and memory. However, more direct evidence of the associations between developmental hypothyroxinemia and impairments of learning and memory should be provided, and the underlying mechanisms remain to be elucidated. Thus, in the present study, we investigated the effects of developmental hypothyroxinemia and hypothyroidism on long-term potentiation (LTP), a widely accepted cellular model of learning and memory, in the hippocampal CA1 region. The activation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway - a pathway closely associated with synaptic plasticity and learning and memory - was also investigated. Wistar rats were treated with iodine deficient diet or methimazole (MMZ) to induce developmental hypothyroxinemia or hypothyroidism. The results showed that developmental hypothyroxinemia caused by mild iodine deficiency and developmental hypothyroidism caused by severe iodine deficiency or MMZ significantly reduced the field-excitatory postsynaptic potential (f-EPSP) slope and the population spike (PS) amplitude. Decreased activation of the PI3K signaling pathway was also observed in rats subjected to developmental hypothyroxinemia or hypothyroidism. Our results may support the hypothesis that neurotoxicity of both developmental hypothyroxinemia and hypothyroidism causes damages to learning and memory. Our results also suggest that decreased activation of the PI3K signaling pathway may contribute to impairments of LTP caused by neurotoxicity of both developmental hypothyroxinemia and hypothyroidism.
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Affiliation(s)
- Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, PR China
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24
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Bougma K, Aboud FE, Harding KB, Marquis GS. Iodine and mental development of children 5 years old and under: a systematic review and meta-analysis. Nutrients 2013; 5:1384-416. [PMID: 23609774 DOI: 10.3390/nu5041384] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/14/2013] [Accepted: 03/22/2013] [Indexed: 11/17/2022] Open
Abstract
Several reviews and meta-analyses have examined the effects of iodine on mental development. None focused on young children, so they were incomplete in summarizing the effects on this important age group. The current systematic review therefore examined the relationship between iodine and mental development of children 5 years old and under. A systematic review of articles using Medline (1980-November 2011) was carried out. We organized studies according to four designs: (1) randomized controlled trial with iodine supplementation of mothers; (2) non-randomized trial with iodine supplementation of mothers and/or infants; (3) prospective cohort study stratified by pregnant women's iodine status; (4) prospective cohort study stratified by newborn iodine status. Average effect sizes for these four designs were 0.68 (2 RCT studies), 0.46 (8 non-RCT studies), 0.52 (9 cohort stratified by mothers' iodine status), and 0.54 (4 cohort stratified by infants' iodine status). This translates into 6.9 to 10.2 IQ points lower in iodine deficient children compared with iodine replete children. Thus, regardless of study design, iodine deficiency had a substantial impact on mental development. Methodological concerns included weak study designs, the omission of important confounders, small sample sizes, the lack of cluster analyses, and the lack of separate analyses of verbal and non-verbal subtests. Quantifying more precisely the contribution of iodine deficiency to delayed mental development in young children requires more well-designed randomized controlled trials, including ones on the role of iodized salt.
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Liu Y, Zhang L, Li J, Shan Z, Teng W. Maternal marginal iodine deficiency affects the expression of relative proteins during brain development in rat offspring. J Endocrinol 2013; 217:21-9. [PMID: 23328070 DOI: 10.1530/joe-12-0410] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Marginal iodine deficiency is a major health problem in pregnant women, but its impact on nerve and intelligence development in offspring has been rarely reported. Our study aimed to investigate the effects of maternal marginal iodine deficiency on nerve and cognitive development in offspring and the related mechanisms. Marginal iodine-deficient rats were given 3 μg iodine per day, while normal control rats were given 4 μg iodine daily. Western blot was used to detect the amounts of brain-derived neurotropic factor (BDNF) and early growth response protein 1 (EGR1) in the hippocampus of each group. Immunohistochemistry was used to measure c-jun and c-fos expression in the hippocampal CA1 region. Finally, the water maze method was used to measure spatial performance. Free thyroxine (FT₄) levels in marginal iodine-deficient rats decreased by about 30%. Seven days after birth, EGR1 and BDNF protein levels significantly decreased in the hippocampus of marginal iodine deficiency rats compared with the normal control group. In addition, c-jun and c-fos expression in the hippocampus of 40-day-old rats was decreased in marginal iodine-deficient rats, compared with control. The spatial learning and memory ability of 40-day-old marginal iodine-deficient rats had a downward trend compared with the normal control group. FT₄ significantly decreased after pregnancy in rats with marginal iodine deficiency, affecting the expression of related proteins in the brain of offspring.
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Affiliation(s)
- Yuhui Liu
- Department of Endocrinology and Metabolism, The Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University, No.155 Nanjing Bei Street, Hepig District, Shenyang 110001, People's Republic of China
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Colin IM, Denef JF, Lengelé B, Many MC, Gérard AC. Recent insights into the cell biology of thyroid angiofollicular units. Endocr Rev 2013; 34:209-38. [PMID: 23349248 PMCID: PMC3610675 DOI: 10.1210/er.2012-1015] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 11/07/2012] [Indexed: 01/06/2023]
Abstract
In thyrocytes, cell polarity is of crucial importance for proper thyroid function. Many intrinsic mechanisms of self-regulation control how the key players involved in thyroid hormone (TH) biosynthesis interact in apical microvilli, so that hazardous biochemical processes may occur without detriment to the cell. In some pathological conditions, this enzymatic complex is disrupted, with some components abnormally activated into the cytoplasm, which can lead to further morphological and functional breakdown. When iodine intake is altered, autoregulatory mechanisms outside the thyrocytes are activated. They involve adjacent capillaries that, together with thyrocytes, form the angiofollicular units (AFUs) that can be considered as the functional and morphological units of the thyroid. In response to iodine shortage, a rapid expansion of the microvasculature occurs, which, in addition to nutrients and oxygen, optimizes iodide supply. These changes are triggered by angiogenic signals released from thyrocytes via a reactive oxygen species/hypoxia-inducible factor/vascular endothelial growth factor pathway. When intra- and extrathyrocyte autoregulation fails, other forms of adaptation arise, such as euthyroid goiters. From onset, goiters are morphologically and functionally heterogeneous due to the polyclonal nature of the cells, with nodules distributed around areas of quiescent AFUs containing globules of compact thyroglobulin (Tg) and surrounded by a hypotrophic microvasculature. Upon TSH stimulation, quiescent AFUs are activated with Tg globules undergoing fragmentation into soluble Tg, proteins involved in TH biosynthesis being expressed and the local microvascular network extending. Over time and depending on physiological needs, AFUs may undergo repetitive phases of high, moderate, or low cell and tissue activity, which may ultimately culminate in multinodular goiters.
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Affiliation(s)
- Ides M Colin
- Pôle de Morphologie, Institut de Recherche Expérimentale et Clinique, Secteur des Sciences de la Santé, Université Catholique de Louvain (UCL), UCL-5251, 52 Avenue E. Mounier, B-1200, Bruxelles, Belgium.
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Gilbert ME, Hedge JM, Valentín-Blasini L, Blount BC, Kannan K, Tietge J, Zoeller RT, Crofton KM, Jarrett JM, Fisher JW. An Animal Model of Marginal Iodine Deficiency During Development: The Thyroid Axis and Neurodevelopmental Outcome*. Toxicol Sci 2013; 132:177-95. [DOI: 10.1093/toxsci/kfs335] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Fisher JW, Li S, Crofton K, Zoeller RT, McLanahan ED, Lumen A, Gilbert ME. Evaluation of Iodide Deficiency in the Lactating Rat and Pup Using a Biologically Based Dose-Response Model*. Toxicol Sci 2013; 132:75-86. [DOI: 10.1093/toxsci/kfs336] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
Severe iodine deficiency is characterized by goiter, preferential synthesis, and secretion of T(3) in thyroids, hypothyroxinemia in plasma and tissues, normal or low plasma T(3), and slightly increased plasma TSH. We studied changes in deiodinase activities and mRNA in several tissues of rats maintained on low-iodine diets (LIDs) or LIDs supplemented with iodine (LID+I). T(4) and T(3) concentrations decreased in plasma, tissues, and thyroids of LID rats, and T(4) decreased more than T(3) (50%). The highest type 1 iodothyronine deiodinase (D1) activities were found in the thyroid, kidney, and the liver; pituitary, lung, and ovary had lower D1 activities; but the lowest levels were found in the heart and skeletal muscle. D1 activity decreased in all tissues of LID rats (10-40% of LID+I rats), except for ovary and thyroids, which D1 activity increased 2.5-fold. Maximal type 2 iodothyronine deiodinase (D2) activities were found in thyroid, brown adipose tissue, and pituitary, increasing 6.5-fold in thyroids of LID rats and about 20-fold in the whole gland. D2 always increased in response to LID, and maximal increases were found in the cerebral cortex (19-fold), thyroid, brown adipose tissue, and pituitary (6-fold). Lower D2 activities were found in the ovary, heart, and adrenal gland, which increased in LID. Type 3 iodothyronine deiodinase activity was undetectable. Thyroidal Dio1 and Dio2 mRNA increased in the LID rats, and Dio1 decreased in the lung, with no changes in mRNA expression in other tissues. Our data indicate that LID induces changes in deiodinase activities, especially in the thyroid, to counteract the low T(4) synthesis and secretion, contributing to maintain the local T(3) concentrations in the tissues with D2 activity.
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Gérard AC, Humblet K, Wilvers C, Poncin S, Derradji H, de Ville de Goyet C, Abou-el-Ardat K, Baatout S, Sonveaux P, Denef JF, Colin IM. Iodine-deficiency-induced long lasting angiogenic reaction in thyroid cancers occurs via a vascular endothelial growth factor-hypoxia inducible factor-1-dependent, but not a reactive oxygen species-dependent, pathway. Thyroid 2012; 22:699-708. [PMID: 22663304 DOI: 10.1089/thy.2011.0387] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND In the thyroid, iodine deficiency (ID) induces angiogenesis via a tightly controlled reactive oxygen species (ROS)-hypoxia inducible factor-1 (HIF-1)-vascular endothelial growth factor (VEGF) dependent pathway (ROS-HIF-VEGF). Deficient iodine intake may be associated with increased thyroid cancer incidence. The hypothesis of this work is to test whether ID affects the angiogenic processes in thyroid malignant cells by altering the ROS-HIF-VEGF pathway. METHODS Goiters were obtained in RET/PTC3 transgenic and wild-type (wt) mice and ID was induced in three thyroid carcinoma cell lines (TPC-1, 8305c, and R082-w1). Thyroid blood flow, VEGF mRNA and protein, and HIF-1α protein expression were measured. The role of HIF-1 and of ROS was assessed using echinomycin and N-acetylcysteine (NAC), respectively. RESULTS The goitrogen treatment increased the thyroid blood flow in wt and RET/PTC3 mice. Compared with wt mice, basal VEGF expression was higher in RET/PTC3 mice and increased with goitrogen treatment. In the three cell lines, ID induced marked increases in VEGF mRNA, and moderate increases in HIF-1α protein expression that were not transient as in normal cells. ID-induced VEGF mRNA expression was fully (8305c), partially (TPC-1), or not (R082-w1) blocked by echinomycin. NAC had no effect on ID-induced VEGF mRNA and HIF-1α protein expression in the three cell lines. CONCLUSIONS ID induces a long lasting angiogenic phenotype in thyroid cancer cells that occurs through VEGF induction via a pathway partially mediated by HIF-1, but not by ROS. These results suggest that, in contrast with normal cells, ID-induced angiogenesis in cancer cells occurs via alternative and likely less controlled routes, thereby leading to uncontrolled growth.
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Affiliation(s)
- Anne-Catherine Gérard
- Department of Morphology, Institute of Experimental and Clinical Research, Catholic University of Louvain, Brussels, Belgium.
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Takeuchi T, Kamasaki H, Yoto Y, Honjo T, Tsugawa S, Hotsubo T, Tsutsumi H. Investigation of iodine deficient state and iodine supplementation in patients with severe motor and intellectual disabilities on long-term total enteral nutrition. Endocr J 2012; 59:697-703. [PMID: 22673532 DOI: 10.1507/endocrj.ej11-0361] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Iodine concentrations of enteral nutrition (EN) formulae available in Japan are very low and long-term total EN (TEN) might result in hypothyroidism due to iodine deficiency (HID). Our aim of this study was to determine the degree of iodine deficiency (ID) and need for iodine supplementation (IS) in patients with severe motor and intellectual disabilities (SMID) on long-term TEN. Thyroid function including urinary iodine concentration (UIC) was monitored, and powdered kelp was provided as a source of iodine supplement. Thirty-five SMID on TEN participated in our study. UIC less than 100 μg /L, representing ID, were detected in 97 % of them. Their TSH ranged from 0.5 to 90 μIU/mL. IS using powdered kelp raised their UIC to the normal range. Thyroid function also recovered in the five hypothyroidism cases, which were diagnosed as HID, was also detected. In Japan, there must be many cases with ID associated with long term TEN. We also discuss the regulation of thyroid function in the iodine deficient state.
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Affiliation(s)
- Takako Takeuchi
- Department of Pediatrics, Sapporo Medical University School of Medicine, Japan.
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Abstract
BACKGROUND Previous studies have shown that thyroxine (T4) is stored as T4 glucuronide (T4G) in the kidney, and that 24 hours after administration of [(125)I]T4 to mice, 17% of the radioactivity was present in the kidneys, whereas only 4% was found in the liver. The present study was carried out to determine the relative amounts of conjugated and unconjugated T4 and 3,5,3'-triiodothyronine (T3) in the kidney and liver, and whether the conjugated hormones are extracted from tissues using our established extraction protocols, and detected in our radioimmunoassays (RIAs) for T4 and T3. METHODS Mice were injected with 10 μCi [(125)I]T4 or [(125)I]T3 and 24 hours later, the labeled compounds present in serum, kidney, liver, and urine were extracted and analyzed by paper chromatography before and after treatment with β-glucuronidase. In addition, the amounts of endogenous T4 and T3 in extracts of mouse kidney and liver were measured by RIA before and after treatment with β-glucuronidase. RESULTS After [(125)I]T4, more than 95% of the total kidney and liver radioactivity was extracted, and in the kidney, almost all of it was present in a conjugated form, mostly as T4G. The liver also contained T4G, but none was present in serum or urine. T3 glucuronide (T3G) was also found in the kidney and liver after the administration of [(125)I]T3. Analysis by RIA of the endogenous T4 content in extracts of kidney before and after hydrolysis by β-glucuronidase revealed that a substantial fraction of the T4 in both tissues was present as T4G, and the T4G was not detected in the RIA. Furthermore, the combined T4+T4G content in the kidney expressed per gram of tissue was significantly higher than that in the liver or serum. In contrast, the kidney content of T3+T3G was very low compared with that of T4+T4G. CONCLUSIONS In summary, we have shown that the kidney stores a significant amount of T4 as T4G. Since T4G deconjugation can occur rapidly in the kidney, it is possible that this tissue participates in maintaining extrathyroidal serum T4 homeostasis.
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Affiliation(s)
- Maarten Buitendijk
- Department of Physiology and Neurobiology, Dartmouth Medical School, Lebanon, New Hampshire 03756, USA
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Barca-Mayo O, Liao XH, DiCosmo C, Dumitrescu A, Moreno-Vinasco L, Wade MS, Sammani S, Mirzapoiazova T, Garcia JGN, Refetoff S, Weiss RE. Role of type 2 deiodinase in response to acute lung injury (ALI) in mice. Proc Natl Acad Sci U S A 2011; 108:E1321-9. [PMID: 22065740 PMCID: PMC3241808 DOI: 10.1073/pnas.1109926108] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Thyroid hormone (TH) metabolism, mediated by deiodinase types 1, 2, and 3 (D1, D2, and D3) is profoundly affected by acute illness. We examined the role of TH metabolism during ventilator-induced lung injury (VILI) in mice. Mice exposed to VILI recapitulated the serum TH findings of acute illness, namely a decrease in 3,5,3'-triiodothyronine (T(3)) and thyroid-stimulating hormone and an increase in reverse T(3). Both D2 immunoreactivity and D2 enzymatic activity were increased significantly. D1 and D3 activity did not change. Using D2 knockout (D2KO) mice, we determined whether the increase in D2 was an adaptive response. Although similar changes in serum TH levels were observed in D2KO and WT mice, D2KO mice exhibited greater susceptibility to VILI than WT mice, as evidenced by poorer alveoli integrity and quantified by lung chemokine and cytokine mRNA induction. These data suggest that an increase in lung D2 is protective against VILI. Similar findings of increased inflammatory markers were found in hypothyroid WT mice exposed to VILI compared with euthyroid mice, indicating that the lungs were functionally hypothyroid. Treatment of D2KO mice with T(3) reversed many of the lung chemokine and cytokine profiles seen in response to VILI, demonstrating a role for T(3) in the treatment of lung injury. We conclude that TH metabolism in the lung is linked to the response to inflammatory injury and speculate that D2 exerts its protective effect by making more TH available to the injured lung tissue.
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Affiliation(s)
| | | | | | | | | | - Michael S. Wade
- Department of Medicine, University of Illinois, Chicago, IL 60612
| | - Saad Sammani
- Department of Medicine, University of Illinois, Chicago, IL 60612
| | | | - Joe G. N. Garcia
- Department of Medicine, University of Illinois, Chicago, IL 60612
| | - Samuel Refetoff
- Departments of Medicine and
- Pediatrics, University of Chicago, Chicago, IL 60637; and
| | - Roy E. Weiss
- Departments of Medicine and
- Pediatrics, University of Chicago, Chicago, IL 60637; and
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Calebiro D, Porazzi P, Bonomi M, Lisi S, Grindati A, De Nittis D, Fugazzola L, Marinò M, Bottà G, Persani L. Absence of primary hypothyroidism and goiter in Slc26a4 (-/-) mice fed on a low iodine diet. J Endocrinol Invest 2011; 34:593-8. [PMID: 20834201 DOI: 10.3275/7262] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Mutations in the SLC26A4 gene, coding for the anion transporter pendrin, are responsible for Pendred syndrome, characterized by congenital sensorineural deafness and dyshormonogenic goiter. The physiological role of pendrin in the thyroid is still unclear and the lack of a thyroid phenotype in some patients with SLC26A4 mutations and in Slc26a4 (-/-) mice indicate the existence of environmental or individual modifiers able to compensate for pendrin inactivation in the thyroid. Since pendrin can transport iodide in vitro, variations in iodide supply have been claimed to account for the thyroid phenotype associated with pendrin defects. AIM The Slc26a4 (-/-) mouse model was used to test the hypothesis that iodide supply may influence the penetrance and expressivity of SLC26A4 mutations. MATERIALS AND METHODS Slc26a4 (-/-) and (+/+) mice were fed up to 6 months on a standard or low iodine diet and were evaluated for thyroid structural abnormalities or biochemical hypothyroidism. RESULTS A 27-fold iodide restriction induced similar modifications in thyroid histology, but no differences in thyroid size, T4 or TSH levels were observed between between Slc26a4 (-/-) and (+/+) mice, either in standard conditions and during iodine restriction. CONCLUSIONS Iodide restriction is not able to induce a thyroid phenotype in Slc26a4 (-/-) mice. These experimental data, together with those coming from a review of familial Pendred cases leaving in regions either with low or sufficient iodide supply, support the idea that the expression of thyroid phenotype in Pendred syndrome is more powerfully influenced by individual factors than by dietary iodide.
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Affiliation(s)
- D Calebiro
- Department of Medical Sciences, University of Milan, Milan, Italy
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Iwata T, Yoshida T, Teranishi M, Murata Y, Hayashi Y, Kanou Y, Griffith AJ, Nakashima T. Influence of dietary iodine deficiency on the thyroid gland in Slc26a4-null mutant mice. Thyroid Res 2011; 4:10. [PMID: 21689387 PMCID: PMC3141755 DOI: 10.1186/1756-6614-4-10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 06/20/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pendred syndrome (PDS) is an autosomal recessive disorder characterized by sensorineural hearing impairment and variable degree of goitrous enlargement of the thyroid gland with a partial defect in iodine organification. The thyroid function phenotype can range from normal function to overt hypothyroidism. It is caused by loss-of-function mutations in the SLC26A4 (PDS) gene. The severity of the goiter has been postulated to depend on the amount of dietary iodine intake. However, direct evidence has not been shown to support this hypothesis. Because Slc26a4-null mice have deafness but do not develop goiter, we fed the mutant mice a control diet or an iodine-deficient diet to evaluate whether iodine deficiency is a causative environmental factor for goiter development in PDS. METHODS We evaluated the thyroid volume in histological sections with the use of three-dimensional reconstitution software, we measured serum levels of total tri-iodothyronine (TT3) and total thyroxine (TT4) levels, and we studied the thyroid gland morphology by transmission electron microscopy. RESULTS TT4 levels became low but TT3 levels did not change significantly after eight weeks of an iodine-deficient diet compared to levels in the control diet animals. Even in Slc26a4-null mice fed an iodine-deficient diet, the volume of the thyroid gland did not increase although the size of each epithelial cell increased with a concomitant decrease of thyroid colloidal area. CONCLUSIONS An iodine-deficient diet did not induce goiter in Slc26a4-null mice, suggesting that other environmental, epigenetic or genetic factors are involved in goiter development in PDS.
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Affiliation(s)
- Tomoyuki Iwata
- Department of Otorhinolaryngology Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan.
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Abstract
There is evidence that isolated maternal hypothyroxinemia may have detrimental effects on both mother and foetus. Nonetheless, this condition is still far from being universally accepted as a separate thyroid disease, and a standard definition of this state of mild thyroid underfunction is still lacking. We will review the biochemical criteria used to define isolated maternal hypothyroxinemia, together with current methodological issues related to FT4 assays. We will also discuss its epidemiological impact in both iodine-deficient and-sufficient areas, and the effectiveness of iodine prophylaxis on maternal thyroid function and neuropsychomotor development in offspring.
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Affiliation(s)
- Mariacarla Moleti
- Sezione di Endocrinologia, Dipartimento Clinico Sperimentale di Medicina e Farmacologia, Università de Messina, 98125 Messina, Italy
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Gilbert M, Mclanahan E, Hedge J, Crofton K, Fisher J, Valentín-blasini L, Blount B. Marginal iodide deficiency and thyroid function: Dose–response analysis for quantitative pharmacokinetic modeling. Toxicology 2011; 283:41-8. [DOI: 10.1016/j.tox.2011.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 02/01/2011] [Accepted: 02/03/2011] [Indexed: 11/19/2022]
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Babu S, Sinha RA, Mohan V, Rao G, Pal A, Pathak A, Singh M, Godbole MM. Effect of hypothyroxinemia on thyroid hormone responsiveness and action during rat postnatal neocortical development. Exp Neurol 2010; 228:91-8. [PMID: 21185833 DOI: 10.1016/j.expneurol.2010.12.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 12/11/2010] [Accepted: 12/14/2010] [Indexed: 11/15/2022]
Abstract
Neurological deficits due to maternal and neonatal hypothyroxinemia under mild-moderate iodine deficiency are a major preventable health problem worldwide. The present study assesses the impact of hypothyroxinemia on postnatal neocortical development and also compares it to the known effects of severe hypothyroidism. Our results strongly suggest that even within elevated circulating triiodothyronine (T3) levels, hypothyroxinemia significantly impairs thyroid hormone responsiveness in developing rat neocortex. The significant compensatory alteration in deiodinase levels with unaltered monocarboxylate transporter 8 (MCT8) and thyroid hormone receptors (TRs), although found to be similar in hypothyroxinemic and hypothyroid condition, is more pronounced under later condition. The resultant downregulation of nuclear myelin binding protein (MBP) and mitochondrial transcripts Cytochrome oxidase III (Cox III) as well as significantly enhanced mitochondrial localization of Bax and reduced Bcl-2 and Bcl-xL accompanied by enhanced release of Cytochrome c and Smac with activation of caspase-3 indicates pronounced apoptosis leading to compromised cellular survival. The similarities of this responsiveness albeit with difference in degree under hypothyroidism and hypothyroxinemic state with adequate availability of T3 are suggestive of an independent role of thyroxine in neocortex development. Taken together, this study brings forth the neurophysiological aspects of hypothyroxinemia and underscores the importance of adequate iodine nutrition along with mandatory thyroxin monitoring during pregnancy and after birth.
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Affiliation(s)
- Satish Babu
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, India
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Saba A, Chiellini G, Frascarelli S, Marchini M, Ghelardoni S, Raffaelli A, Tonacchera M, Vitti P, Scanlan TS, Zucchi R. Tissue distribution and cardiac metabolism of 3-iodothyronamine. Endocrinology 2010; 151:5063-73. [PMID: 20739399 DOI: 10.1210/en.2010-0491] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
3-iodothyronamine (T1AM) is a novel relative of thyroid hormone, able to interact with specific G protein-coupled receptors, known as trace amine-associated receptors. Significant functional effects are produced by exogenous T1AM, including a negative inotropic and chronotropic effect in cardiac preparations. This work was aimed at estimating endogenous T1AM concentration in different tissues and determining its cardiac metabolism. A novel HPLC tandem mass spectrometry assay was developed, allowing detection of T1AM, thyronamine, 3-iodothyroacetic acid, and thyroacetic acid. T1AM was detected in rat serum, at the concentration of 0.3±0.03 pmol/ml, and in all tested organs (heart, liver, kidney, skeletal muscle, stomach, lung, and brain), at concentrations significantly higher than the serum concentration, ranging from 5.6±1.5 pmol/g in lung to 92.9±28.5 pmol/g in liver. T1AM was also identified for the first time in human blood. In H9c2 cardiomyocytes and isolated perfused rat hearts, significant Na+-dependent uptake of exogenous T1AM was observed, and at the steady state total cellular or tissue T1AM concentration exceeded extracellular concentration by more than 20-fold. In both preparations T1AM underwent oxidative deamination to 3-iodothyroacetic acid. T1AM deamination was inhibited by iproniazid but not pargyline or semicarbazide, suggesting the involvement of both monoamine oxidase and semicarbazide-sensitive amine oxidase. Thyronamine and thyroacetic acid were not detected in heart. Finally, evidence of T1AM production was observed in cardiomyocytes exposed to exogenous thyroid hormone, although the activity of this pathway was very low.
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Affiliation(s)
- Alessandro Saba
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via Roma 55, 56126 Pisa, Italy
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Saba A, Chiellini G, Frascarelli S, Marchini M, Ghelardoni S, Raffaelli A, Tonacchera M, Vitti P, Scanlan TS, Zucchi R. Tissue Distribution and Cardiac Metabolism of 3-Iodothyronamine. Endocrinology 2010. [DOI: 10.1210/en.2010-0491 pmid: 20739399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
3-Iodothyronamine (T1AM) is a novel relative of thyroid hormone, able to interact with specific G protein-coupled receptors, known as trace amine-associated receptors. Significant functional effects are produced by exogenous T1AM, including a negative inotropic and chronotropic effect in cardiac preparations. This work was aimed at estimating endogenous T1AM concentration in different tissues and determining its cardiac metabolism. A novel HPLC tandem mass spectrometry assay was developed, allowing detection of T1AM, thyronamine, 3-iodothyroacetic acid, and thyroacetic acid. T1AM was detected in rat serum, at the concentration of 0.3 ± 0.03 pmol/ml, and in all tested organs (heart, liver, kidney, skeletal muscle, stomach, lung, and brain), at concentrations significantly higher than the serum concentration, ranging from 5.6 ± 1.5 pmol/g in lung to 92.9 ± 28.5 pmol/g in liver. T1AM was also identified for the first time in human blood. In H9c2 cardiomyocytes and isolated perfused rat hearts, significant Na+-dependent uptake of exogenous T1AM was observed, and at the steady state total cellular or tissue T1AM concentration exceeded extracellular concentration by more than 20-fold. In both preparations T1AM underwent oxidative deamination to 3-iodothyroacetic acid. T1AM deamination was inhibited by iproniazid but not pargyline or semicarbazide, suggesting the involvement of both monoamine oxidase and semicarbazide-sensitive amine oxidase. Thyronamine and thyroacetic acid were not detected in heart. Finally, evidence of T1AM production was observed in cardiomyocytes exposed to exogenous thyroid hormone, although the activity of this pathway was very low.
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Affiliation(s)
- Alessandro Saba
- Dipartimento di Chimica e Chimica Industriale (A.S.), University of Pisa, 56126 Pisa, Italy
| | - Grazia Chiellini
- Dipartimento di Scienze dell’Uomo e dell’Ambiente (G.C., S.F., M.M., S.G., R.Z.), University of Pisa, 56126 Pisa, Italy
| | - Sabina Frascarelli
- Dipartimento di Scienze dell’Uomo e dell’Ambiente (G.C., S.F., M.M., S.G., R.Z.), University of Pisa, 56126 Pisa, Italy
| | - Maja Marchini
- Dipartimento di Scienze dell’Uomo e dell’Ambiente (G.C., S.F., M.M., S.G., R.Z.), University of Pisa, 56126 Pisa, Italy
| | - Sandra Ghelardoni
- Dipartimento di Scienze dell’Uomo e dell’Ambiente (G.C., S.F., M.M., S.G., R.Z.), University of Pisa, 56126 Pisa, Italy
| | - Andrea Raffaelli
- Consiglio Nazionale delle Ricerche (A.R.), Istituto di Chimica dei Composti Organo Metallici, Pisa, Italy
| | - Massimo Tonacchera
- Dipartimento di Endocrinologia (M.T., P.V.), University of Pisa, 56126 Pisa, Italy
| | - Paolo Vitti
- Dipartimento di Endocrinologia (M.T., P.V.), University of Pisa, 56126 Pisa, Italy
| | - Thomas S. Scanlan
- Departments of Physiology and Pharmacology and Cell and Developmental Biology (T.S.S.), Oregon Health and Science University, Portland, Oregon 97239
| | - Riccardo Zucchi
- Dipartimento di Scienze dell’Uomo e dell’Ambiente (G.C., S.F., M.M., S.G., R.Z.), University of Pisa, 56126 Pisa, Italy
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Di Cosmo C, Liao XH, Dumitrescu AM, Philp NJ, Weiss RE, Refetoff S. Mice deficient in MCT8 reveal a mechanism regulating thyroid hormone secretion. J Clin Invest 2010; 120:3377-88. [PMID: 20679730 DOI: 10.1172/jci42113] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 06/16/2010] [Indexed: 11/17/2022] Open
Abstract
The mechanism of thyroid hormone (TH) secretion from the thyroid gland into blood is unknown. Humans and mice deficient in monocarboxylate transporter 8 (MCT8) have low serum thyroxine (T4) levels that cannot be fully explained by increased deiodination. Here, we have shown that Mct8 is localized at the basolateral membrane of thyrocytes and that the serum TH concentration is reduced in Mct8-KO mice early after being taken off a treatment that almost completely depleted the thyroid gland of TH. Thyroid glands in Mct8-KO mice contained more non-thyroglobulin-associated T4 and triiodothyronine than did those in wild-type mice, independent of deiodination. In addition, depletion of thyroidal TH content was slower during iodine deficiency. After administration of 125I, the rate of both its secretion from the thyroid gland and its appearance in the serum as trichloroacetic acid-precipitable radioactivity was greatly reduced in Mct8-KO mice. Similarly, the secretion of T4 induced by injection of thyrotropin was reduced in Mct8-KO in which endogenous TSH and T4 were suppressed by administration of triiodothyronine. To our knowledge, this study is the first to demonstrate that Mct8 is involved in the secretion of TH from the thyroid gland and contributes, in part, to the low serum T4 level observed in MCT8-deficient patients.
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Affiliation(s)
- Caterina Di Cosmo
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
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Pol CJ, Muller A, Simonides WS. Cardiomyocyte-specific inactivation of thyroid hormone in pathologic ventricular hypertrophy: an adaptative response or part of the problem? Heart Fail Rev 2010; 15:133-42. [PMID: 19107595 DOI: 10.1007/s10741-008-9133-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recent studies in various rodent models of pathologic ventricular hypertrophy report the re-expression of deiodinase type 3 (D3) in cardiomyocytes. D3 inactivates thyroid hormone (T3) and is mainly expressed in tissues during development. The stimulation of D3 activity in ventricular hypertrophy and subsequent heart failure is associated with severe impairment of cardiac T3 signaling. Hypoxia-induced signaling appears to drive D3 expression in the hypertrophic cardiomyocyte, but other signaling cascades implicated in hypertrophy are also capable of stimulating transcription of the DIO3 gene. Many cardiac genes are transcriptionally regulated by T3 and impairment of T3 signaling will not only reduce energy turnover, but also lead to changes in gene expression that contribute to contractile dysfunction in pathologic remodeling. Whether stimulation of D3 activity and the ensuing local T3-deficiency is an adaptive response of the stressed heart or part of the pathologic signaling network leading to heart failure, remains to be established.
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Zewdie T, Smith CM, Hutcheson M, West CR. Basis of the Massachusetts reference dose and drinking water standard for perchlorate. Environ Health Perspect 2010; 118:42-48. [PMID: 20056583 PMCID: PMC2831965 DOI: 10.1289/ehp.0900635] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 01/30/2009] [Accepted: 07/13/2009] [Indexed: 05/28/2023]
Abstract
OBJECTIVE Perchlorate inhibits the uptake of iodide in the thyroid. Iodide is required to synthesize hormones critical to fetal and neonatal development. Many water supplies and foods are contaminated with perchlorate. Exposure standards are needed but controversial. Here we summarize the basis of the Massachusetts (MA) perchlorate reference dose (RfD) and drinking water standard (DWS), which are considerably lower and more health protective than related values derived by several other agencies. We also review information regarding perchlorate risk assessment and policy. DATA SOURCES MA Department of Environmental Protection (DEP) scientists, with input from a science advisory committee, assessed a wide range of perchlorate risk and exposure information. Health outcomes associated with iodine insufficiency were considered, as were data on perchlorate in drinking water disinfectants. DATA SYNTHESIS We used a weight-of-the-evidence approach to evaluate perchlorate risks, paying particular attention to sensitive life stages. A health protective RfD (0.07 microg/kg/day) was derived using an uncertainty factor approach with perchlorate-induced iodide uptake inhibition as the point of departure. The MA DWS (2 microg/L) was based on risk management decisions weighing information on perchlorate health risks and its presence in certain disinfectant solutions used to treat drinking water for pathogens. CONCLUSIONS Current data indicate that perchlorate exposures attributable to drinking water in individuals at sensitive life stages should be minimized and support the MA DEP perchlorate RfD and DWS. Widespread exposure to perchlorate and other thyroid toxicants in drinking water and foods suggests that more comprehensive policies to reduce overall exposures and enhance iodine nutrition are needed.
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Affiliation(s)
| | - C. Mark Smith
- Address correspondence to C.M. Smith, Massachusetts Department of Environmental Protection, Office of Research and Standards, 1 Winter St., Boston, MA 02108 USA. Telephone: (617) 292-5509. Fax: (617) 556-1006. E-mail:
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Opitz R, Schmidt F, Braunbeck T, Wuertz S, Kloas W. Perchlorate and ethylenethiourea induce different histological and molecular alterations in a non-mammalian vertebrate model of thyroid goitrogenesis. Mol Cell Endocrinol 2009; 298:101-14. [PMID: 18801409 DOI: 10.1016/j.mce.2008.08.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Accepted: 08/19/2008] [Indexed: 11/20/2022]
Abstract
Despite evidence for a conserved role of thyroid-stimulating hormone (TSH) in regulating vertebrate thyroid function, molecular data on thyroid responses to TSH are mainly limited to mammalian species. In this study, we examined histological and molecular changes in the thyroid of Xenopus laevis tadpoles during a 12-day treatment with 20mg/l perchlorate (PER) and 50mg/l ethylenethiourea (ETU). Inhibition of thyroid hormone (TH) synthesis by PER and ETU was evident from developmental retardation, reduced expression of TH-regulated genes and up-regulation of tshb-A mRNA. Thyroid histopathology revealed goiters with strikingly different follicular morphologies following PER and ETU treatment. Using real-time PCR, we analyzed thyroids sampled on day 12 for differential expression of 60 candidate genes. Further temporal analyses were performed for a subset of 14 genes. Relative to the control, PER and ETU treatment modulated the expression of 51 and 49 transcripts, respectively. Particularly genes related to TH synthesis and protein metabolism were similarly affected by PER and ETU. However, several genes were differentially expressed in PER- and ETU-treated tadpoles. Specifically, goiter formation in the PER treatment was associated with low expression of genes related to DNA replication but high expression of negative growth regulators. Results from this work provide for the first time a characterization of gene expression profiles during goitrogenesis in a non-mammalian vertebrate model. Overall, our data suggest that, in addition to TSH over-stimulation, further mechanisms related to the mode of goitrogen action contribute to the regulation of thyroid gene expression.
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Affiliation(s)
- R Opitz
- Department of Inland Fisheries, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
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Moreno JC, Klootwijk W, van Toor H, Pinto G, D'Alessandro M, Lèger A, Goudie D, Polak M, Grüters A, Visser TJ. Mutations in the iodotyrosine deiodinase gene and hypothyroidism. N Engl J Med 2008; 358:1811-8. [PMID: 18434651 DOI: 10.1056/nejmoa0706819] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
DEHAL1 has been identified as the gene encoding iodotyrosine deiodinase in the thyroid, where it controls the reuse of iodide for thyroid hormone synthesis. We screened patients with hypothyroidism who had features suggestive of an iodotyrosine deiodinase defect for mutations in DEHAL1. Two missense mutations and a deletion of three base pairs were identified in four patients from three unrelated families; all the patients had a dramatic reduction of in vitro activity of iodotyrosine deiodinase. Patients had severe goitrous hypothyroidism, which was evident in infancy and childhood. Two patients had cognitive deficits due to late diagnosis and treatment. Thus, mutations in DEHAL1 led to a deficiency in iodotyrosine deiodinase in these patients. Because infants with DEHAL1 defects may have normal thyroid function at birth, they may be missed by neonatal screening programs for congenital hypothyroidism.
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Affiliation(s)
- José C Moreno
- Department of Internal Medicine, Erasmus Medical Center, Erasmus University, Rotterdam, The Netherlands.
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47
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McLanahan ED, Andersen ME, Fisher JW. A biologically based dose-response model for dietary iodide and the hypothalamic-pituitary-thyroid axis in the adult rat: evaluation of iodide deficiency. Toxicol Sci 2008; 102:241-53. [PMID: 18178547 DOI: 10.1093/toxsci/kfm312] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A biologically based dose-response (BBDR) model was developed for dietary iodide and the hypothalamic-pituitary-thyroid (HPT) axis in adult rats. This BBDR-HPT axis model includes submodels for dietary iodide, thyroid-stimulating hormone (TSH), and the thyroid hormones, T(4) and T(3). The submodels are linked together via key biological processes, including (1) the influence of T(4) on TSH production (the HPT axis negative feedback loop), (2) stimulation of thyroidal T(4) and T(3) production by TSH, (3) TSH upregulation of the thyroid sodium (Na(+))/iodide symporter, and (4) recycling of iodide from metabolism of thyroid hormones. The BBDR-HPT axis model was calibrated to predict steady-state concentrations of iodide, T(4), T(3), and TSH for the euthyroid rat whose dietary intake of iodide was 20 mug/day. Then the BBDR-HPT axis model was used to predict perturbations in the HPT axis caused by insufficient dietary iodide intake, and simulation results were compared to experimental findings. The BBDR-HPT axis model was successful in simulating perturbations in serum T(4), TSH, and thyroid iodide stores for low-iodide diets of 0.33-1.14 mug/day. Model predictions of serum T(3) concentrations were inconsistent with observations in some cases. BBDR-HPT axis model simulations show a steep dose-response relationship between dietary intake of iodide and serum T(4) and TSH when dietary iodide intake becomes insufficient (less than 2 mug/day) to sustain the HPT axis. This BBDR-HPT axis model can be linked with physiologically based pharmacokinetic models for thyroid-active chemicals to evaluate and predict dose-dependent HPT axis alterations based on hypothesized modes of action. To support continued development of this model, future studies should include time course data after perturbation of the HPT axis to capture changes in endogenous iodide, serum TSH, T(4), and T(3).
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Affiliation(s)
- Eva D McLanahan
- University of Georgia, Interdisciplinary Toxicology Program, Athens, Georgia 30602, USA
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Palos F, García-Rendueles MER, Araujo-Vilar D, Obregon MJ, Calvo RM, Cameselle-Teijeiro J, Bravo SB, Perez-Guerra O, Loidi L, Czarnocka B, Alvarez P, Refetoff S, Dominguez-Gerpe L, Alvarez CV, Lado-Abeal J. Pendred syndrome in two Galician families: insights into clinical phenotypes through cellular, genetic, and molecular studies. J Clin Endocrinol Metab 2008; 93:267-77. [PMID: 17940114 PMCID: PMC2190748 DOI: 10.1210/jc.2007-0539] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Accepted: 10/09/2007] [Indexed: 11/19/2022]
Abstract
CONTEXT We studied two families from Galicia (northwest Spain) with Pendred syndrome (PS) and unusual thyroid phenotypes. In family A, the proposita had a large goiter and hypothyroxinemia but normal TSH and free T3 (FT3). In family B, some affected members showed deafness but not goiter. OBJECTIVE Our objective was to identify the mutations causing PS and molecular mechanisms underlying the thyroid phenotypes. INTERVENTIONS Interventions included extraction of DNA and of thyroid tissue. PATIENTS Propositi and 10 members of the two families participated in the study. MAIN OUTCOME MEASURES Main outcome measures included SLC26A4 gene analysis, deiodinase activities in thyroid tissue, and c.416-1G-->A effects on SLC26A4 splicing. In addition, a primary PS thyrocyte culture, T-PS2, was obtained from propositus B and compared with another culture of normal human thyrocytes, NT, by Western blotting, confocal microscopy, and iodine uptake kinetics. RESULTS Proposita A was heterozygous for c.578C-->T and c.279delT, presented with goiter, and had normal TSH and FT3 but low FT4 attributable to high type 1 and type 2 iodothyronine deiodinase activities in the goiter. Propositus B bore c.279delT and a novel mutation c.416-1G-->A; some deaf relatives were homozygous for c.416-1G-->A but did not present goiter. The c.279delT mutation was associated with identical haplotype in the two families. T-PS2 showed truncated pendrin retained intracellularly and high iodine uptake with low efflux leading to iodine retention. CONCLUSIONS c.279delT is a founder mutation in Galicia. Proposita A adapted to poor organification by increasing deiodinase activities in the goiter, avoiding hypothyroidism. Lack of goiter in subjects homozygous for c.416-1G-->A was due to incomplete penetrance allowing synthesis of some wild-type pendrin. Intracellular iodine retention, as seen in T-PS2, could play a role in thyroid alterations in PS.
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Affiliation(s)
- Fernando Palos
- Unidade de Enfermedades Tiroideas e Metabólicas, Department of Medicine, University of Santiago de Compostela, C/ San Francisco sn, Santiago de Compostela 15705, Spain
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Morreale de Escobar G, Escobar del Rey F. Metabolismo de las hormonas tiroideas y el yodo en el embarazo. Razones experimentales para mantener una ingesta de yodo adecuada en la gestación. ACTA ACUST UNITED AC 2008; 55:7-17. [DOI: 10.1016/s1575-0922(08)76239-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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