51
|
Nassan FL, Korevaar TIM, Coull BA, Skakkebæk NE, Krawetz SA, Estill M, Hait EJ, Korzenik JR, Ford JB, De Poortere RA, Broeren MA, Moss AC, Zoeller TR, Hauser R. Dibutyl-phthalate exposure from mesalamine medications and serum thyroid hormones in men. Int J Hyg Environ Health 2018; 222:101-110. [PMID: 30170956 DOI: 10.1016/j.ijheh.2018.08.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/14/2018] [Accepted: 08/14/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Dibutyl phthalate (DBP) is an endocrine disruptor and used in some medication coatings, such as mesalamine for treatment inflammatory bowel disease (IBD). OBJECTIVES To determine whether high-DBP from some mesalamine medications alters thyroid function. METHODS Seventy men with IBD, without thyroid disease or any radiation history participated in a crossover-crossback prospective study and provided up to 6 serum samples (2:baseline, 2:crossover, 2:crossback). Men on non-DBP mesalamine (background exposure) at baseline crossed-over to DBP-mesalamine (high exposure) then crossed-back to non-DBP mesalamine (B1HB2-arm) and vice versa for men on DBP-mesalamine at baseline (H1BH2-arm). Serum concentrations of total triiodothyronine (T3), total thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb). RESULTS After crossover in B1HB2-arm (26 men, 134 samples), T3 decreased 10% (95% confidence interval (CI): 14%,-5%), T3/T4 ratio decreased 8% (CI: 12%,-3%), TPOAb, and TgAb concentrations decreased, 11% (-20%, -2%) and 15% (-23%, -5%), respectively; after crossback, they increased. When men in the H1BH2-arm (44 men, 193 samples) crossed-over, T3 decreased 7% (CI: -11%, -2%) and T3/T4 ratio decreased 6% (CI: -9%, -2%). After crossback, only TgAb increased and FT4 decreased. CONCLUSIONS High-DBP novel exposure or removal from chronic high-DBP exposure could alter elements of the thyroid system, and most probably alters the peripheral T4 conversion to T3 and thyroid autoimmunity, consistent with thyroid disruption. After exposure removal, these trends were mostly reversed.
Collapse
Affiliation(s)
- Feiby L Nassan
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, USA; Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
| | - Tim I M Korevaar
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Brent A Coull
- Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Niels E Skakkebæk
- Department of Growth and Reproduction, EDMaRC, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Stephen A Krawetz
- Department of Obstetrics & Gynecology, Center for Molecular Medicine & Genetics, Wayne State University, Detroit, MI, USA
| | - Molly Estill
- Department of Obstetrics & Gynecology, Center for Molecular Medicine & Genetics, Wayne State University, Detroit, MI, USA
| | - Elizabeth J Hait
- Division of Gastroenterology, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
| | - Joshua R Korzenik
- Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jennifer B Ford
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Ralph A De Poortere
- Laboratory of Clinical Chemistry and Haematology, Máxima Medical Centre, Veldhoven, De Run, 4600, the Netherlands
| | - Maarten A Broeren
- Laboratory of Clinical Chemistry and Haematology, Máxima Medical Centre, Veldhoven, De Run, 4600, the Netherlands
| | - Alan C Moss
- Center for Inflammatory Bowel Disease, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Thomas R Zoeller
- Department of Biology, University of Massachusetts, Amherst, MA, USA
| | - Russ Hauser
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, USA; Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, USA; Vincent Obstetrics and Gynecology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| |
Collapse
|
52
|
Berger K, Gunier RB, Chevrier J, Calafat AM, Ye X, Eskenazi B, Harley KG. Associations of maternal exposure to triclosan, parabens, and other phenols with prenatal maternal and neonatal thyroid hormone levels. ENVIRONMENTAL RESEARCH 2018; 165:379-386. [PMID: 29803919 PMCID: PMC6470297 DOI: 10.1016/j.envres.2018.05.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/24/2018] [Accepted: 05/07/2018] [Indexed: 05/05/2023]
Abstract
Environmental phenols and parabens are commonly used in personal care products and other consumer products and human exposure to these chemicals is widespread. Although human and animal studies suggest an association between exposure to phenols and parabens and thyroid hormone levels, few studies have investigated the association of in utero exposure to these chemicals and thyroid hormones in pregnant women and their neonates. We measured four environmental phenols (triclosan, benzophenone-3, and 2,4- and 2,5-dichlorophenol), and three parabens (methyl-, propyl-, and butyl paraben) in urine collected from mothers at two time points during pregnancy as part of the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study. We measured free thyroxine (T4), total T4, and thyroid-stimulating hormone (TSH) in serum of the pregnant women (N = 454) and TSH in their neonates (N = 365). We examined potential confounding by a large number of additional chemical exposures and used Bayesian Model Averaging (BMA) to select the most influential chemicals to include in regression models. We observed negative associations of prenatal urinary concentrations of propyl paraben and maternal TSH (β for two-fold increase = -3.26%, 95% CI: -5.55, -0.90) and negative associations of 2,4-dichlorophenol and maternal free T4 (β for two-fold increase = -0.05, 95% CI: -0.08, -0.02), after controlling for other chemical exposures. We observed negative associations of triclosan with maternal total T4 after controlling for demographic variables, but this association became non-significant after controlling for other chemicals (β for two-fold increase = -0.05, 95% CI: -0.11, 0.00). We found evidence that environmental phenols and parabens are associated with lower TSH and free T4 in pregnant women after controlling for related chemical exposures.
Collapse
Affiliation(s)
- Kimberly Berger
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, 1995 University Avenue, Berkeley, CA 94704, USA
| | - Robert B Gunier
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, 1995 University Avenue, Berkeley, CA 94704, USA
| | - Jonathan Chevrier
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, 1995 University Avenue, Berkeley, CA 94704, USA
| | - Antonia M Calafat
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy, Atlanta, GA 30341, USA
| | - Xiaoyun Ye
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy, Atlanta, GA 30341, USA
| | - Brenda Eskenazi
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, 1995 University Avenue, Berkeley, CA 94704, USA
| | - Kim G Harley
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, 1995 University Avenue, Berkeley, CA 94704, USA.
| |
Collapse
|
53
|
Calcification Patterns in Papillary Thyroid Carcinoma are Associated with Changes in Thyroid Hormones and Coronary Artery Calcification. J Clin Med 2018; 7:jcm7080183. [PMID: 30049993 PMCID: PMC6111282 DOI: 10.3390/jcm7080183] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 12/14/2022] Open
Abstract
Recent studies suggested that a lower serum thyroid hormone level is associated with more vascular calcification. However, it has been rarely evaluated whether lower thyroid hormone levels affect the calcification of thyroid cancer and there is a relationship between calcification patterns of papillary thyroid carcinoma (PTC) and coronary artery calcification (CAC). The study was divided into two groups: First, we retrospectively reviewed 182 PTC patients and examined the correlation between PTC calcification patterns and CAC by coronary computed tomography (CT). Second, the correlation between the calcification pattern of PTC and thyroid hormone concentration was investigated (n = 354). The calcification pattern of PTC was evaluated by thyroid ultrasonography and classified into four groups: no-calcification, microcalcification, macrocalcification, and mixed-calcification. In PTC patients with microcalcification and mixed calcification, more CAC was observed and coronary calcium score (CCS) was higher. Lower free T4 and higher thyroid-stimulating hormone (TSH) levels were associated with microcalcification and mixed calcification, not with macrocalcification and no calcification. PTC with microcalcification and mixed calcification showed more aggressive phenotypes like lymph node metastasis and more advanced TNM (tumor, node, and metastasis) stage than those with no calcification and macrocalcification. Calcification patterns of PTC showed close association with thyroid hormone levels and CAC. Further research is needed to determine how these findings are related to cardiovascular risk and disease-specific mortality.
Collapse
|
54
|
Berberich J, Dietrich JW, Hoermann R, Müller MA. Mathematical Modeling of the Pituitary-Thyroid Feedback Loop: Role of a TSH-T 3-Shunt and Sensitivity Analysis. Front Endocrinol (Lausanne) 2018; 9:91. [PMID: 29619006 PMCID: PMC5871688 DOI: 10.3389/fendo.2018.00091] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 02/26/2018] [Indexed: 01/08/2023] Open
Abstract
Despite significant progress in assay technology, diagnosis of functional thyroid disorders may still be a challenge, as illustrated by the vague upper limit of the reference range for serum thyrotropin (TSH). Diagnostical problems also apply to subjects affected by syndrome T, i.e., those 10% of hypothyroid patients who continue to suffer from poor quality of life despite normal TSH concentrations under substitution therapy with levothyroxine (L-T4). In this paper, we extend a mathematical model of the pituitary-thyroid feedback loop in order to improve the understanding of thyroid hormone homeostasis. In particular, we incorporate a TSH-T3-shunt inside the thyroid, whose existence has recently been demonstrated in several clinical studies. The resulting extended model shows good accordance with various clinical observations, such as a circadian rhythm in free peripheral triiodothyronine (FT3). Furthermore, we perform a sensitivity analysis of the derived model, revealing the dependence of TSH and hormone concentrations on different system parameters. The results have implications for clinical interpretation of thyroid tests, e.g., in the differential diagnosis of subclinical hypothyroidism.
Collapse
Affiliation(s)
- Julian Berberich
- Institute for Systems Theory and Automatic Control, University of Stuttgart, Stuttgart, Germany
| | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Bochum, Germany
| | - Rudolf Hoermann
- Private Consultancy Research & Development, Yandina, QLD, Australia
| | - Matthias A. Müller
- Institute for Systems Theory and Automatic Control, University of Stuttgart, Stuttgart, Germany
- *Correspondence: Matthias A. Müller,
| |
Collapse
|
55
|
Fitzgerald SP, Bean NG. Population correlations do not support the existence of set points for blood levels of calcium or glucose - a new model for homeostasis. Physiol Rep 2018; 6:e13551. [PMID: 29333728 PMCID: PMC5789653 DOI: 10.14814/phy2.13551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023] Open
Abstract
The prevailing teaching regarding homeostasis, and in particular endocrine homeostasis, includes the fundamental concept of a "set point," which represents a target or optimum level defended by physiological control mechanisms. Analogies for the description and teaching of this concept have included thermostats and cruise controls. We previously demonstrated that such a set-point model of regulation implies that in population data of parameter set point/controlling hormone levels, correlations between the parameter and its controlling hormone must be in the direction of the response of the parameter to its controlling hormone, and that in thyroid homeostasis this relationship is not observed. In this work we similarly examined population correlations, extracted from the literature, for the parameters glucose and calcium, and their controlling hormones. We found 10 correlations. Most were highly significant (P < 0.01). All were in the direction of the response of the controlling hormone to the parameter. Therefore, none were consistent with the pattern implied by a set-point model of regulation. Instead all were consistent with an "equilibrium point" model of regulation, whereby ambient levels have no particular connotation to the individual, and result passively from the interplay of physiological processes. We conclude that glucose and calcium regulation, like thyroid regulation, are not centered on set points. This may reflect a general property of homeostasis. We provide an alternative mechanistic analogy, without a set point, for the heuristic description and teaching, of homeostasis.
Collapse
Affiliation(s)
| | - Nigel G. Bean
- School of Mathematical Sciences and ARC Centre of Excellence for Mathematical and Statistical FrontiersUniversity of AdelaideAdelaideSouth AustraliaAustralia
| |
Collapse
|
56
|
Dietrich JW, Midgley JEM, Hoermann R. Editorial: "Homeostasis and Allostasis of Thyroid Function". Front Endocrinol (Lausanne) 2018; 9:287. [PMID: 29922229 PMCID: PMC5996081 DOI: 10.3389/fendo.2018.00287] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/15/2018] [Indexed: 12/14/2022] Open
Affiliation(s)
- Johannes W. Dietrich
- Medical Department 1, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, North Rhine-Westphalia, Germany
- Ruhr Centre of Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, North Rhine-Westphalia, Germany
- Ruhr Centre of Rare Diseases (CeSER), Witten/Herdecke University, Bochum, North Rhine-Westphalia, Germany
- *Correspondence: Johannes W. Dietrich,
| | | | - Rudolf Hoermann
- Private Consultancy, Research and Development, Yandina, QLD, Australia
| |
Collapse
|
57
|
Hoermann R, Midgley JEM, Larisch R, Dietrich JWC. Advances in applied homeostatic modelling of the relationship between thyrotropin and free thyroxine. PLoS One 2017; 12:e0187232. [PMID: 29155897 PMCID: PMC5695809 DOI: 10.1371/journal.pone.0187232] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/16/2017] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION The relationship between pituitary TSH and thyroid hormones is central to our understanding of thyroid physiology and thyroid function testing. Here, we generated distribution patterns by using validated tools of thyroid modelling. METHODS We simulated patterns of individual set points under various conditions, based on a homeostatic model of thyroid feedback control. These were compared with observed data points derived from clinical trials. RESULTS A random mix of individual set points was reconstructed by simulative modelling with defined structural parameters. The pattern displayed by the cluster of hypothetical points resembled that observed in a natural control group. Moderate variation of the TSH-FT4 gradient over the functional range introduced further flexibility, implementing a scenario of adaptive set points. Such a scenario may be a realistic possibility for instance in treatment where relationships and equilibria between thyroid parameters are altered by various influences such as LT4 dose and conversion efficiency. CONCLUSIONS We validated a physiologically based homeostatic model that permits simulative reconstruction of individual set points. This produced a pattern resembling the observed data under various conditions. Applied modelling, although still experimental at this stage, shows a potential to aid our physiological understanding of the interplay between TSH and thyroid hormones. It should eventually benefit personalised clinical decision making.
Collapse
Affiliation(s)
- Rudolf Hoermann
- Department for Nuclear Medicine, Klinikum Lüdenscheid, Paulmannshöherstr, Lüdenscheid, Germany
| | | | - Rolf Larisch
- Department for Nuclear Medicine, Klinikum Lüdenscheid, Paulmannshöherstr, Lüdenscheid, Germany
| | - Johannes Wolfgang Christian Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Alexandrinenstr. 5, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Alexandrinenstr. 5, Bochum, Germany
| |
Collapse
|
58
|
Kim HI, Kim TH, Kim H, Kim YN, Jang HW, Kim JH, Hur KY, Chung JH, Kim SW. Delayed TSH recovery after dose adjustment during TSH-suppressive levothyroxine therapy of thyroid cancer. Clin Endocrinol (Oxf) 2017; 87:286-291. [PMID: 28375573 DOI: 10.1111/cen.13344] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 03/09/2017] [Accepted: 03/30/2017] [Indexed: 01/10/2023]
Abstract
BACKGROUND Delayed thyroid-stimulating hormone (TSH) recovery during treatment of Graves' disease is caused by long-term excessive thyroid hormone, which results in downregulation of pituitary thyrotrophs. However, it is unknown whether delayed TSH recovery exists after levothyroxine (LT4) dose reduction in patients with differentiated thyroid cancer (DTC) after long-term TSH suppression. METHODS We retrospectively reviewed 97 DTC patients with LT4 dose reduction after long-term TSH suppression. TSH levels at baseline (point 1), 6 months (point 2) and 12-18 months (point 3) after LT4 dose reduction were compared. A delayed TSH recovery group whose TSH levels changed to upper target TSH category (2015 revised ATA guidelines) from point 2 to point 3 was identified, and risk factors were analysed. RESULTS The median TSH level at point 3 was significantly higher than that of point 2 (0.17 vs 0.09 mIU/L; P<.001). The delayed TSH recovery group (44.3%) showed increased body weight (60.84 vs 62.73 kg; P=.01), while normal response group did not. Greater reduction (%) in the LT4 dose per weight [HR 1.10, 95% CI (1.00-1.22), P=.04] and higher BMI before thyroid surgery [1.19, 1.03-1.38, P=.01] predicted the occurrence of delayed TSH recovery, while higher dose of LT4 per weight after reduction showed preventive effect [HR 0.01, 95% CI (0.00-0.54); P=.02]. CONCLUSIONS Delayed TSH recovery was common during LT4 dose reduction after long-term TSH suppression for DTC management. Six months may not be enough for TSH recovery and to evaluate thyroid hormone status by serum TSH.
Collapse
Affiliation(s)
- Hye In Kim
- Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Tae Hyuk Kim
- Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hosu Kim
- Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Young Nam Kim
- Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hye Won Jang
- Department of Medical Education, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jung-Han Kim
- Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Kyu Yeon Hur
- Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jae Hoon Chung
- Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sun Wook Kim
- Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| |
Collapse
|
59
|
Gienapp P, Laine VN, Mateman AC, van Oers K, Visser ME. Environment-Dependent Genotype-Phenotype Associations in Avian Breeding Time. Front Genet 2017; 8:102. [PMID: 28824697 PMCID: PMC5543038 DOI: 10.3389/fgene.2017.00102] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/24/2017] [Indexed: 01/16/2023] Open
Abstract
Understanding how genes shape phenotypes is essential to assess the evolutionary potential of a trait. Identifying the genes underlying quantitative behavioral or life-history traits has, however, proven to be a major challenge. The majority of these traits are phenotypically plastic and different parts of the genome can be involved in shaping the trait under different environmental conditions. These variable genotype-phenotype associations could be one explanation for the limited success of genome-wide association studies in such traits. We here use avian seasonal timing of breeding, a trait that is highly plastic in response to spring temperature, to explore effects of such genotype-by-environment interactions in genome-wide association studies. We genotyped 2045 great tit females for 384081 single nucleotide polymorphisms (SNPs) and recorded their egg-laying dates in the wild. When testing for associations between SNPs and egg-laying dates, no SNP reached genome-wide significance. We then explored whether SNP effects were modified by annual spring temperature by formally testing for an interaction between SNP effect and temperature. The models including the SNP∗temperature interaction performed consistently better although no SNP reached genome-wide significance. Our results suggest that the effects of genes shaping seasonal timing depended on annual spring temperature. Such environment-dependent effects are expected for any phenotypically plastic trait. Taking these effects into account will thus improve the success of detecting genes involved in phenotypically plastic traits, thereby leading to a better understanding of their evolutionary potential.
Collapse
Affiliation(s)
- Phillip Gienapp
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW)Wageningen, Netherlands
| | - Veronika N Laine
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW)Wageningen, Netherlands
| | - A C Mateman
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW)Wageningen, Netherlands
| | - Kees van Oers
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW)Wageningen, Netherlands
| | - Marcel E Visser
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW)Wageningen, Netherlands
| |
Collapse
|
60
|
Fitzgerald SP, Bean NG, Fitzgerald LN. Population data indicate that thyroid regulation is consistent with an equilibrium-point model, but not with a set-point model. Temperature (Austin) 2017; 4:114-116. [PMID: 28680925 PMCID: PMC5489013 DOI: 10.1080/23328940.2017.1281370] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Stephen Paul Fitzgerald
- Department of Internal Medicine, Department of Endocrinology, The Royal Adelaide Hospital, Adelaide 5000, South Australia.,School of Medicine, The University of Adelaide, SA 5005, Australia
| | - Nigel Geoffrey Bean
- School Of Mathematical Sciences, The University of Adelaide, SA 5005, Australia.,ARC Centre of Excellence for Mathematical and Statistical Frontiers, The University of Adelaide, SA 5005, Australia
| | | |
Collapse
|
61
|
García M, González de Buitrago J, Jiménez-Rosés M, Pardo L, Hinkle PM, Moreno JC. Central Hypothyroidism Due to a TRHR Mutation Causing Impaired Ligand Affinity and Transactivation of Gq. J Clin Endocrinol Metab 2017; 102:2433-2442. [PMID: 28419241 PMCID: PMC5505191 DOI: 10.1210/jc.2016-3977] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/12/2017] [Indexed: 11/19/2022]
Abstract
CONTEXT Central congenital hypothyroidism (CCH) is an underdiagnosed disorder characterized by deficient production and bioactivity of thyroid-stimulating hormone (TSH) leading to low thyroid hormone synthesis. Thyrotropin-releasing hormone (TRH) receptor (TRHR) defects are rare recessive disorders usually associated with incidentally identified CCH and short stature in childhood. OBJECTIVES Clinical and genetic characterization of a consanguineous family of Roma origin with central hypothyroidism and identification of underlying molecular mechanisms. DESIGN All family members were phenotyped with thyroid hormone profiles, pituitary magnetic resonance imaging, TRH tests, and dynamic tests for other pituitary hormones. Candidate TRH, TRHR, TSHB, and IGSF1 genes were screened for mutations. A mutant TRHR was characterized in vitro and by molecular modeling. RESULTS A homozygous missense mutation in TRHR (c.392T > C; p.I131T) was identified in an 8-year-old boy with moderate hypothyroidism (TSH: 2.61 mIU/L, Normal: 0.27 to 4.2; free thyroxine: 9.52 pmol/L, Normal: 10.9 to 25.7) who was overweight (body mass index: 20.4 kg/m2, p91) but had normal stature (122 cm; -0.58 standard deviation). His mother, two brothers, and grandmother were heterozygous for the mutation with isolated hyperthyrotropinemia (TSH: 4.3 to 8 mIU/L). The I131T mutation, in TRHR intracellular loop 2, decreases TRH affinity and increases the half-maximal effective concentration for signaling. Modeling of TRHR-Gq complexes predicts that the mutation disrupts the interaction between receptor and a hydrophobic pocket formed by Gq. CONCLUSIONS A unique missense TRHR defect identified in a consanguineous family is associated with central hypothyroidism in homozygotes and hyperthyrotropinemia in heterozygotes, suggesting compensatory elevation of TSH with reduced biopotency. The I131T mutation decreases TRH binding and TRHR-Gq coupling and signaling.
Collapse
Affiliation(s)
- Marta García
- Thyroid Molecular Laboratory, Institute for Medical and Molecular Genetics, La Paz University Hospital, Autonomous University of Madrid, 28046 Madrid, Spain
| | | | - Mireia Jiménez-Rosés
- Computational Medicine Laboratory, Biostatistics Unit, Autonomous University of Barcelona, 08193 Barcelona, Spain
| | - Leonardo Pardo
- Computational Medicine Laboratory, Biostatistics Unit, Autonomous University of Barcelona, 08193 Barcelona, Spain
| | - Patricia M. Hinkle
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York 14642
| | - José C. Moreno
- Thyroid Molecular Laboratory, Institute for Medical and Molecular Genetics, La Paz University Hospital, Autonomous University of Madrid, 28046 Madrid, Spain
| |
Collapse
|
62
|
Shi WJ, Ying GG, Huang GY, Liang YQ, Hu LX, Zhao JL, Zhang JN. Transcriptional and Biochemical Alterations in Zebrafish Eleuthero-Embryos (Danio rerio) After Exposure to Synthetic Progestogen Dydrogesterone. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2017; 99:39-45. [PMID: 28214940 DOI: 10.1007/s00128-017-2046-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/07/2017] [Indexed: 06/06/2023]
Abstract
Little information has so far been known on the effects of synthetic progestogen dydrogesterone (DDG) in organisms like fish. This study aimed to investigate the effects of DDG on the transcriptional and biochemical alterations in zebrafish eleuthero-embryos. Zebrafish eleuthero-embryos were analyzed for the transcriptional alterations by real-time quantitative PCR (RT-qPCR) and biochemical changes by attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FITR) after 144 h exposure to DDG. The results of qPCR analysis showed that DDG exposure significantly suppressed the transcriptions of target genes involved in hypothalamic-pituitary-thyroid (HPT) axis, while it induced the expression of target genes mRNA belonging to hypothalamic-pituitary-gonad (HPG) axis. In addition, ATR-FTIR spectroscopy analysis showed that the biochemical alterations of protein, nucleic acid and lipid were observed following DDG treatment. The finding from this study suggests that DDG exposure could have potential multiple effects in fish.
Collapse
Affiliation(s)
- Wen-Jun Shi
- State Key Laboratory of Organic Geochemistry, CAS Research Centre of PRD Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640, Guangzhou, China
| | - Guang-Guo Ying
- State Key Laboratory of Organic Geochemistry, CAS Research Centre of PRD Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640, Guangzhou, China.
| | - Guo-Yong Huang
- State Key Laboratory of Organic Geochemistry, CAS Research Centre of PRD Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640, Guangzhou, China
| | - Yan-Qiu Liang
- State Key Laboratory of Organic Geochemistry, CAS Research Centre of PRD Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640, Guangzhou, China
- School of Chemistry and Environment, Guangdong Ocean University, 524088, Zhanjiang, China
| | - Li-Xin Hu
- State Key Laboratory of Organic Geochemistry, CAS Research Centre of PRD Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640, Guangzhou, China
| | - Jian-Liang Zhao
- State Key Laboratory of Organic Geochemistry, CAS Research Centre of PRD Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640, Guangzhou, China
| | - Jin-Na Zhang
- State Key Laboratory of Organic Geochemistry, CAS Research Centre of PRD Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640, Guangzhou, China
| |
Collapse
|
63
|
Hoermann R, Midgley JEM, Dietrich JW, Larisch R. Dual control of pituitary thyroid stimulating hormone secretion by thyroxine and triiodothyronine in athyreotic patients. Ther Adv Endocrinol Metab 2017; 8:83-95. [PMID: 28794850 PMCID: PMC5524252 DOI: 10.1177/2042018817716401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/29/2017] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Patient responses to levothyroxine (LT4) monotherapy vary considerably. We sought to differentiate contributions of FT4 and FT3 in controlling pituitary thyroid stimulating hormone (TSH) secretion. METHODS We retrospectively assessed the relationships between TSH and thyroid hormones in 319 patients with thyroid carcinoma through 2914 visits on various LT4 doses during follow-up for 5.5 years (median, IQR 4.2, 6.9). We also associated patient complaints with the relationships. RESULTS Under varying dose requirements (median 1.84 µg/kg, IQR 1.62, 2.11), patients reached TSH targets below 0.4, 0.1 or 0.01 mIU/l at 73%, 54% and 27% of visits. While intercept, slope and fit of linearity of the relationships between lnTSH and FT4/FT3 varied between individuals, gender, age, LT4 dose and deiodinase activity influenced the relationships in the cohort (all p < 0.001). Deiodinase activity impaired by LT4 dose significantly affected the lnTSH-FT4 relationship. Dose increase and reduced conversion efficiency displaced FT3-TSH equilibria. In LT4-treated patients, FT4 and FT3 contributed on average 52% versus 38%, and by interaction 10% towards TSH suppression. Symptomatic presentations (11%) accompanied reduced FT3 concentrations (-0.23 pmol/l, p = 0.001) adjusted for gender, age and BMI, their relationships being shifted towards higher TSH values at comparable FT3/FT4 levels. CONCLUSIONS Variation in deiodinase activity and resulting FT3 levels shape the TSH-FT4 relationship in LT4-treated athyreotic patients, suggesting cascade control of pituitary TSH production by the two hormones. Consequently, measurement of FT3 and calculation of conversion efficiency may identify patients with impaired biochemistry and a resulting lack of symptomatic control.
Collapse
Affiliation(s)
- Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Lüdenscheid, Paulmannshoeher Str 14, D-58515 Luedenscheid, Germany
| | | | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
| | - Rolf Larisch
- Department of Nuclear Medicine, Klinikum Lüdenscheid, Lüdenscheid, Germany
| |
Collapse
|
64
|
Ballesteros V, Costa O, Iñiguez C, Fletcher T, Ballester F, Lopez-Espinosa MJ. Exposure to perfluoroalkyl substances and thyroid function in pregnant women and children: A systematic review of epidemiologic studies. ENVIRONMENT INTERNATIONAL 2017; 99:15-28. [PMID: 27884404 DOI: 10.1016/j.envint.2016.10.015] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 10/14/2016] [Accepted: 10/17/2016] [Indexed: 05/18/2023]
Abstract
INTRODUCTION Thyroid hormones (THs) are especially important for brain maturation and development during the fetal period and childhood. Several epidemiological studies have assessed the possible association between exposure to perfluoroalkyl substances (PFAS) and thyroid outcomes during the early stages of life. We aimed to review this evidence. METHODS We conducted a systematic review in compliance with the PRISMA Statement (search conducted in PubMed and Embase, as well as in the citations of the selected articles). We chose studies if they dealt with thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxin (T4), or thyroid dysfunctions, and perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS) or perfluorononanoic acid (PFNA) measured in the blood of pregnant women and/or children up to 19years old. RESULTS We included in this review three cross-sectional, one case-control, and six cohort studies (publication: 2011-2015), focusing on prenatal life (n=7), childhood (n=2) or both periods (n=1). We observed a high degree of heterogeneity across studies in terms of sampling time (different gestational weeks, at birth, or childhood), outcomes, adjustment for potential confounders, and statistical approach. We found some evidence of a positive association between PFHxS and PFOS exposure and TSH levels measured in maternal blood, and PFNA and TSH levels measured in the blood of boys aged ≥11years. CONCLUSION Although there is a small number of studies with comparable data, we found some consistency of a positive association between maternal or teenage male exposure to some PFAS and TSH levels based on the current literature. However, further studies are required to confirm these possible relationships.
Collapse
Affiliation(s)
- Virginia Ballesteros
- Andalusian Health and Environment Observatory (OSMAN), Andalusian School of Public Health, Campus Universitario de Cartuja, Cuesta del Observatorio, 4, 18011 Granada, Spain; Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, Avenida de Catalunya 21, 46020 Valencia, Spain
| | - Olga Costa
- Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, Avenida de Catalunya 21, 46020 Valencia, Spain
| | - Carmen Iñiguez
- Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, Avenida de Catalunya 21, 46020 Valencia, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Calle Monforte de Lemos 3-5, Madrid 28029, Spain
| | - Tony Fletcher
- London School of Hygiene & Tropical Medicine, 15-17 Tavistock Place, London WC1H 9SH, United Kingdom
| | - Ferran Ballester
- Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, Avenida de Catalunya 21, 46020 Valencia, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Calle Monforte de Lemos 3-5, Madrid 28029, Spain
| | - Maria-Jose Lopez-Espinosa
- Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, Avenida de Catalunya 21, 46020 Valencia, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Calle Monforte de Lemos 3-5, Madrid 28029, Spain.
| |
Collapse
|
65
|
Chatzitomaris A, Hoermann R, Midgley JE, Hering S, Urban A, Dietrich B, Abood A, Klein HH, Dietrich JW. Thyroid Allostasis-Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming. Front Endocrinol (Lausanne) 2017; 8:163. [PMID: 28775711 PMCID: PMC5517413 DOI: 10.3389/fendo.2017.00163] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/27/2017] [Indexed: 12/21/2022] Open
Abstract
The hypothalamus-pituitary-thyroid feedback control is a dynamic, adaptive system. In situations of illness and deprivation of energy representing type 1 allostasis, the stress response operates to alter both its set point and peripheral transfer parameters. In contrast, type 2 allostatic load, typically effective in psychosocial stress, pregnancy, metabolic syndrome, and adaptation to cold, produces a nearly opposite phenotype of predictive plasticity. The non-thyroidal illness syndrome (NTIS) or thyroid allostasis in critical illness, tumors, uremia, and starvation (TACITUS), commonly observed in hospitalized patients, displays a historically well-studied pattern of allostatic thyroid response. This is characterized by decreased total and free thyroid hormone concentrations and varying levels of thyroid-stimulating hormone (TSH) ranging from decreased (in severe cases) to normal or even elevated (mainly in the recovery phase) TSH concentrations. An acute versus chronic stage (wasting syndrome) of TACITUS can be discerned. The two types differ in molecular mechanisms and prognosis. The acute adaptation of thyroid hormone metabolism to critical illness may prove beneficial to the organism, whereas the far more complex molecular alterations associated with chronic illness frequently lead to allostatic overload. The latter is associated with poor outcome, independently of the underlying disease. Adaptive responses of thyroid homeostasis extend to alterations in thyroid hormone concentrations during fetal life, periods of weight gain or loss, thermoregulation, physical exercise, and psychiatric diseases. The various forms of thyroid allostasis pose serious problems in differential diagnosis of thyroid disease. This review article provides an overview of physiological mechanisms as well as major diagnostic and therapeutic implications of thyroid allostasis under a variety of developmental and straining conditions.
Collapse
Affiliation(s)
- Apostolos Chatzitomaris
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- *Correspondence: Apostolos Chatzitomaris,
| | - Rudolf Hoermann
- Private Consultancy, Research and Development, Yandina, QLD, Australia
| | | | - Steffen Hering
- Department for Internal Medicine, Cardiology, Endocrinology, Diabetes and Medical Intensive Care Medicine, Krankenhaus Bietigheim-Vaihingen, Bietigheim-Bissingen, Germany
| | - Aline Urban
- Department for Anesthesiology, Intensive Care and Palliative Medicine, Eastern Allgäu-Kaufbeuren Hospitals, Kaufbeuren, Germany
| | | | - Assjana Abood
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
| | - Harald H. Klein
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
| | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
| |
Collapse
|
66
|
Hoermann R, Midgley JEM, Larisch R, Dietrich JW. Relational Stability in the Expression of Normality, Variation, and Control of Thyroid Function. Front Endocrinol (Lausanne) 2016; 7:142. [PMID: 27872610 PMCID: PMC5098235 DOI: 10.3389/fendo.2016.00142] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 10/21/2016] [Indexed: 12/31/2022] Open
Abstract
Thyroid hormone concentrations only become sufficient to maintain a euthyroid state through appropriate stimulation by pituitary thyroid-stimulating hormone (TSH). In such a dynamic system under constant high pressure, guarding against overstimulation becomes vital. Therefore, several defensive mechanisms protect against accidental overstimulation, such as plasma protein binding, conversion of T4 into the more active T3, active transmembrane transport, counter-regulatory activities of reverse T3 and thyronamines, and negative hypothalamic-pituitary-thyroid feedback control of TSH. TSH has gained a dominant but misguided role in interpreting thyroid function testing in assuming that its exceptional sensitivity thereby translates into superior diagnostic performance. However, TSH-dependent thyroid disease classification is heavily influenced by statistical analytic techniques such as uni- or multivariate-defined normality. This demands a separation of its conjoint roles as a sensitive screening test and accurate diagnostic tool. Homeostatic equilibria (set points) in healthy subjects are less variable and do not follow a pattern of random variation, rather indicating signs of early and progressive homeostatic control across the euthyroid range. In the event of imminent thyroid failure with a reduced FT4 output per unit TSH, conversion efficiency increases in order to maintain FT3 stability. In such situations, T3 stability takes priority over set point maintenance. This suggests a concept of relational stability. These findings have important implications for both TSH reference limits and treatment targets for patients on levothyroxine. The use of archival markers is proposed to facilitate the homeostatic interpretation of all parameters.
Collapse
Affiliation(s)
- Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| | | | - Rolf Larisch
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Bochum, Germany
| |
Collapse
|
67
|
Johns LE, Ferguson KK, McElrath TF, Mukherjee B, Meeker JD. Associations between Repeated Measures of Maternal Urinary Phthalate Metabolites and Thyroid Hormone Parameters during Pregnancy. ENVIRONMENTAL HEALTH PERSPECTIVES 2016; 124:1808-1815. [PMID: 27152641 PMCID: PMC5089879 DOI: 10.1289/ehp170] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 01/13/2016] [Accepted: 04/27/2016] [Indexed: 05/18/2023]
Abstract
BACKGROUND Maintaining thyroid homeostasis during pregnancy is essential for normal fetal growth and development. Growing evidence suggests that phthalates interfere with normal thyroid function. Few human studies have investigated the degree to which phthalates may affect thyroid hormone levels in particularly susceptible populations such as pregnant women. OBJECTIVES We examined the associations between repeated measures of urinary phthalate metabolites and plasma thyroid hormone levels in samples collected at up to four time points per subject in pregnancy. Additionally, we investigated the potential windows of susceptibility to thyroid hormone disturbances related to study visit of sample collection. METHODS Data were obtained from pregnant women (n = 439) participating in a nested case-control study of preterm birth with 116 cases and 323 controls. We measured 9 phthalate metabolite concentrations in urine samples collected at up to four study visits per subject during pregnancy (median = 10, 18, 26, and 35 weeks of gestation, respectively). We also measured a panel of thyroid function markers in plasma collected at the same four time points per subject during pregnancy. RESULTS Although our results were generally null, in repeated measures analyses we observed that phthalate metabolites were largely inversely associated with thyrotropin and positively associated with free and total thyroid hormones. Cross-sectional analyses by study visit revealed that the magnitude and/or direction of these relationships varied by timing of exposure during gestation. CONCLUSIONS These results support previous reports showing the potential for environmental phthalate exposure to alter circulating levels of thyroid hormones in pregnant women. Citation: Johns LE, Ferguson KK, McElrath TF, Mukherjee B, Meeker JD. 2016. Associations between repeated measures of maternal urinary phthalate metabolites and thyroid hormone parameters during pregnancy. Environ Health Perspect 124:1808-1815; http://dx.doi.org/10.1289/EHP170.
Collapse
Affiliation(s)
- Lauren E. Johns
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Kelly K. Ferguson
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Thomas F. McElrath
- Division of Maternal and Fetal Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Bhramar Mukherjee
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - John D. Meeker
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
- Address correspondence to J.D. Meeker, University of Michigan School of Public Health, Department of Environmental Health Sciences, 1835 SPH I, 1415 Washington Heights, Ann Arbor, MI 48109-2029 USA. Telephone: (734) 764-7184. E-mail:
| |
Collapse
|
68
|
Hoermann R, Midgley JE, Larisch R, Dietrich JW. Relational Stability of Thyroid Hormones in Euthyroid Subjects and Patients with Autoimmune Thyroid Disease. Eur Thyroid J 2016; 5:171-179. [PMID: 27843807 PMCID: PMC5091265 DOI: 10.1159/000447967] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 06/21/2016] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND/AIM Operating far from its equilibrium resting point, the thyroid gland requires stimulation via feedback-controlled pituitary thyrotropin (TSH) secretion to maintain adequate hormone supply. We explored and defined variations in the expression of control mechanisms and physiological responses across the euthyroid reference range. METHODS We analyzed the relational equilibria between thyroid parameters defining thyroid production and thyroid conversion in a group of 271 thyroid-healthy subjects and 86 untreated patients with thyroid autoimmune disease. RESULTS In the euthyroid controls, the FT3-FT4 (free triiodothyronine-free thyroxine) ratio was strongly associated with the FT4-TSH ratio (tau = -0.22, p < 0.001, even after correcting for spurious correlation), linking T4 to T3 conversion with TSH-standardized T4 production. Using a homeostatic model, we estimated both global deiodinase activity and maximum thyroid capacity. Both parameters were nonlinearly and inversely associated, trending in opposite directions across the euthyroid reference range. Within the panel of controls, the subgroup with a relatively lower thyroid capacity (<2.5 pmol/s) displayed lower FT4 levels, but maintained FT3 at the same concentrations as patients with higher functional and anatomical capacity. The relationships were preserved when extended to the subclinical range in the diseased sample. CONCLUSION The euthyroid panel does not follow a homogeneous pattern to produce random variation among thyroid hormones and TSH, but forms a heterogeneous group that progressively displays distinctly different levels of homeostatic control across the euthyroid range. This suggests a concept of relational stability with implications for definition of euthyroidism and disease classification.
Collapse
Affiliation(s)
- Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
- *Prof. Dr. Rudolf Hoermann, Department of Nuclear Medicine, Klinikum Luedenscheid, Paulmannshoeher Strasse 14, DE-58515 Luedenscheid (Germany), E-Mail
| | | | - Rolf Larisch
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
| |
Collapse
|
69
|
Hoermann R, Larisch R, Dietrich JW, Midgley JEM. Derivation of a multivariate reference range for pituitary thyrotropin and thyroid hormones: diagnostic efficiency compared with conventional single-reference method. Eur J Endocrinol 2016; 174:735-43. [PMID: 26951601 DOI: 10.1530/eje-16-0031] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/07/2016] [Indexed: 12/16/2022]
Abstract
UNLABELLED : Although pituitary thyrotropin (TSH) and thyroid hormones are physiologically interrelated, interpretation of measurements is conventionally done separately. Classification of subclinical thyroid dysfunction depends by definition solely on an abnormal TSH. This study examines a composite multivariate approach to disease classification. METHODS Bivariate and trivariate reference limits were derived from a thyroid-healthy control group (n=271) and applied to a clinically diverse sample (n=820) from a prospective study, comparing their diagnostic efficiency with the conventional method. RESULTS The following 95% reference limits were derived from the control group: (i) separate reference intervals for TSH, free thyroxine (FT4) and free triiodothyronine (FT3); (ii) bivariate composite reference limits for the logarithmically transformed TSH and FT4, and (iii) trivariate composite reference limits including all three parameters. A multivariate approach converts the "rectangular" or "cuboid" graphical representations of the independent parameters into an ellipse or ellipsoid. When applying these reference limits to the clinical sample, thyroid dysfunctions were classified differently, compared with the separate method, in 6.3 or 12% of all cases by the bivariate or trivariate method respectively. Of the established dysfunctions according to the separate intervals, 26% were reclassified to "euthyroid" by using the bivariate limit. Discrepancies from the laboratory-evaluated reference range were less pronounced. CONCLUSIONS Frequent divergencies between composite multivariate reference limits and a combination of separate univariate reference intervals suggest that statistical analytic techniques may heavily influence thyroid disease classification. This challenges the validity of the conjoined roles of TSH currently employed as both a sensitive screening test and a reliable classification tool for thyroid disease.
Collapse
Affiliation(s)
- Rudolf Hoermann
- Department for Nuclear MedicineKlinikum Lüdenscheid, Lüdenscheid, Germany
| | - Rolf Larisch
- Department for Nuclear MedicineKlinikum Lüdenscheid, Lüdenscheid, Germany
| | - Johannes W Dietrich
- Medical Department IEndocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany Ruhr Center for Rare Diseases (CeSER)Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
| | | |
Collapse
|
70
|
Alayoubi A, Sullivan RD, Lou H, Patel H, Mandrell T, Helms R, Almoazen H. In Vivo Evaluation of Transdermal Iodide Microemulsion for Treating Iodine Deficiency Using Sprague Dawley Rats. AAPS PharmSciTech 2016; 17:618-30. [PMID: 26288943 DOI: 10.1208/s12249-015-0392-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/09/2015] [Indexed: 11/30/2022] Open
Abstract
The objective of this study was to evaluate the transdermal efficiency of iodide microemulsion in treating iodine deficiency using rats as an animal model. Animals were fed either iodine-deficient diet (20 μg/kg iodide) or control diet (200 μg/kg iodide) over a 17-month period. At month 14, iodide microemulsion was applied topically in iodine-deficient group and physiological evaluations of thyroid gland functions were characterized by monitoring the thyroid hormones (T3, T4), thyroid-stimulating hormone (TSH), iodide ion excretion in urine, and the overall rat body weights in both groups. Moreover, morphological evaluations of thyroid gland before and after treatment were performed by ultrasound imaging and through histological assessment. Prior to microemulsion treatment, the levels of T3, T4, and TSH in iodine-deficient group were statistically significant as compared to that in the control group. The levels of T3 and T4 increased while TSH level decreased significantly in iodine-deficient group within the first 4 weeks of treatment. After treatment, iodide concentration in urine increased significantly. There was no statistical difference in weight between the two groups. Ultrasound imaging and histological evaluations showed evidence of hyperplasia in iodine-deficient group. Topical iodide microemulsion has shown a promising potential as a novel delivery system to treat iodine deficiency.
Collapse
|
71
|
The Relationship between Population T4/TSH Set Point Data and T4/TSH Physiology. J Thyroid Res 2016; 2016:6351473. [PMID: 27123359 PMCID: PMC4830732 DOI: 10.1155/2016/6351473] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 02/29/2016] [Indexed: 12/21/2022] Open
Abstract
Context. Population studies of the distribution of T4/TSH set points suggest a more complex inverse relationship between T4 and TSH than that suggested by physiological studies. The reasons for the similarities and differences between the curves describing these relationships are unresolved. Methods. We subjected the curve, derived from empiric data, describing the TSH suppression response to T4, and the more mathematically derived curve describing the T4 response to TSH, to the different possible models of population variation. The implied consequences of these in terms of generating a population distribution of T4/TSH equilibrium points (a “population curve”) were generated and compared to the empiric population curve. The physiological responses to primary hypothyroidism and hyperthyroidism were incorporated into the analysis. Conclusions. Though the population curve shows a similarly inverse relationship, it is describing a different relationship than the curve describing the suppression of TSH by T4. The population curve is consistent with the physiological studies of the TSH response to T4 and implies a greater interindividual variation in the positive thyroid T4 response to TSH than in the central inhibitory TSH response to T4. The population curve in the dysthyroid states is consistent with known physiological responses to these states.
Collapse
|
72
|
Dietrich JW, Landgrafe-Mende G, Wiora E, Chatzitomaris A, Klein HH, Midgley JEM, Hoermann R. Calculated Parameters of Thyroid Homeostasis: Emerging Tools for Differential Diagnosis and Clinical Research. Front Endocrinol (Lausanne) 2016; 7:57. [PMID: 27375554 PMCID: PMC4899439 DOI: 10.3389/fendo.2016.00057] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/23/2016] [Indexed: 11/30/2022] Open
Abstract
Although technical problems of thyroid testing have largely been resolved by modern assay technology, biological variation remains a challenge. This applies to subclinical thyroid disease, non-thyroidal illness syndrome, and those 10% of hypothyroid patients, who report impaired quality of life, despite normal thyrotropin (TSH) concentrations under levothyroxine (L-T4) replacement. Among multiple explanations for this condition, inadequate treatment dosage and monotherapy with L-T4 in subjects with impaired deiodination have received major attention. Translation to clinical practice is difficult, however, since univariate reference ranges for TSH and thyroid hormones fail to deliver robust decision algorithms for therapeutic interventions in patients with more subtle thyroid dysfunctions. Advances in mathematical and simulative modeling of pituitary-thyroid feedback control have improved our understanding of physiological mechanisms governing the homeostatic behavior. From multiple cybernetic models developed since 1956, four examples have also been translated to applications in medical decision-making and clinical trials. Structure parameters representing fundamental properties of the processing structure include the calculated secretory capacity of the thyroid gland (SPINA-GT), sum activity of peripheral deiodinases (SPINA-GD) and Jostel's TSH index for assessment of thyrotropic pituitary function, supplemented by a recently published algorithm for reconstructing the personal set point of thyroid homeostasis. In addition, a family of integrated models (University of California-Los Angeles platform) provides advanced methods for bioequivalence studies. This perspective article delivers an overview of current clinical research on the basis of mathematical thyroid models. In addition to a summary of large clinical trials, it provides previously unpublished results of validation studies based on simulation and clinical samples.
Collapse
Affiliation(s)
- Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Bochum, Germany
- *Correspondence: Johannes W. Dietrich,
| | - Gabi Landgrafe-Mende
- Zentrum für Unfallchirurgie, Orthopädie und Wirbelsäulenchirurgie, HELIOS Klinikum Schwelm, Schwelm, Germany
| | - Evelin Wiora
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
| | - Apostolos Chatzitomaris
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
| | - Harald H. Klein
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Witten/Herdecke University, Bochum, Germany
| | | | - Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| |
Collapse
|
73
|
Midgley JEM, Larisch R, Dietrich JW, Hoermann R. Variation in the biochemical response to l-thyroxine therapy and relationship with peripheral thyroid hormone conversion efficiency. Endocr Connect 2015; 4:196-205. [PMID: 26335522 PMCID: PMC4557078 DOI: 10.1530/ec-150056] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Several influences modulate biochemical responses to a weight-adjusted levothyroxine (l-T4) replacement dose. We conducted a secondary analysis of the relationship of l-T4 dose to TSH and free T3 (FT3), using a prospective observational study examining the interacting equilibria between thyroid parameters. We studied 353 patients on steady-state l-T4 replacement for autoimmune thyroiditis or after surgery for malignant or benign thyroid disease. Peripheral deiodinase activity was calculated as a measure of T4-T3 conversion efficiency. In euthyroid subjects, the median l-T4 dose was 1.3 μg/kg per day (interquartile range (IQR) 0.94,1.60). The dose was independently associated with gender, age, aetiology and deiodinase activity (all P<0.001). Comparable FT3 levels required higher l-T4 doses in the carcinoma group (n=143), even after adjusting for different TSH levels. Euthyroid athyreotic thyroid carcinoma patients (n=50) received 1.57 μg/kg per day l-T4 (IQR 1.40, 1.69), compared to 1.19 μg/kg per day (0.85,1.47) in autoimmune thyroiditis (P<0.01, n=76) and 1.08 μg/kg per day (0.82, 1.44) in patients operated on for benign disease (P< 0.01, n=80). Stratifying patients by deiodinase activity categories of <23, 23-29 and >29 nmol/s revealed an increasing FT3-FT4 dissociation; the poorest converters showed the lowest FT3 levels in spite of the highest dose and circulating FT4 (P<0.001). An l-T4-related FT3-TSH disjoint was also apparent; some patients with fully suppressed TSH failed to raise FT3 above the median level. These findings imply that thyroid hormone conversion efficiency is an important modulator of the biochemical response to l-T4; FT3 measurement may be an additional treatment target; and l-T4 dose escalation may have limited success to raise FT3 appropriately in some cases.
Collapse
Affiliation(s)
- John E M Midgley
- North Lakes Clinical20 Wheatley Avenue, Ilkley LS29 8PT, UKDepartment of Nuclear MedicineKlinikum Luedenscheid, Paulmannshoeher Strasse 14, D-58515 Luedenscheid, GermanyMedical Department IEndocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Buerkle-de-la-Camp-Platz 1, D-44789 Bochum, GermanyRuhr Center for Rare Diseases (CeSER)Ruhr University of Bochum and Witten/Herdecke University, Alexandrinenstraße 5, D-44791 Bochum, Germany
| | - Rolf Larisch
- North Lakes Clinical20 Wheatley Avenue, Ilkley LS29 8PT, UKDepartment of Nuclear MedicineKlinikum Luedenscheid, Paulmannshoeher Strasse 14, D-58515 Luedenscheid, GermanyMedical Department IEndocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Buerkle-de-la-Camp-Platz 1, D-44789 Bochum, GermanyRuhr Center for Rare Diseases (CeSER)Ruhr University of Bochum and Witten/Herdecke University, Alexandrinenstraße 5, D-44791 Bochum, Germany
| | - Johannes W Dietrich
- North Lakes Clinical20 Wheatley Avenue, Ilkley LS29 8PT, UKDepartment of Nuclear MedicineKlinikum Luedenscheid, Paulmannshoeher Strasse 14, D-58515 Luedenscheid, GermanyMedical Department IEndocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Buerkle-de-la-Camp-Platz 1, D-44789 Bochum, GermanyRuhr Center for Rare Diseases (CeSER)Ruhr University of Bochum and Witten/Herdecke University, Alexandrinenstraße 5, D-44791 Bochum, Germany North Lakes Clinical20 Wheatley Avenue, Ilkley LS29 8PT, UKDepartment of Nuclear MedicineKlinikum Luedenscheid, Paulmannshoeher Strasse 14, D-58515 Luedenscheid, GermanyMedical Department IEndocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Buerkle-de-la-Camp-Platz 1, D-44789 Bochum, GermanyRuhr Center for Rare Diseases (CeSER)Ruhr University of Bochum and Witten/Herdecke University, Alexandrinenstraße 5, D-44791 Bochum, Germany
| | - Rudolf Hoermann
- North Lakes Clinical20 Wheatley Avenue, Ilkley LS29 8PT, UKDepartment of Nuclear MedicineKlinikum Luedenscheid, Paulmannshoeher Strasse 14, D-58515 Luedenscheid, GermanyMedical Department IEndocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Buerkle-de-la-Camp-Platz 1, D-44789 Bochum, GermanyRuhr Center for Rare Diseases (CeSER)Ruhr University of Bochum and Witten/Herdecke University, Alexandrinenstraße 5, D-44791 Bochum, Germany
| |
Collapse
|
74
|
Abstract
BACKGROUND AND AIMS Accurate diagnosis and treatment of subclinical hypothyroidism (SCH) is challenging in clinical practice because of differing upper limits of normal (ULN) for thyroid-stimulating hormone (TSH). This review summarises the various definitions of SCH and their impact on reported SCH prevalence. METHODOLOGY Articles reporting the prevalence of SCH in relation to the ULN of TSH in human studies were identified through an English-language PubMed search for 'subclinical hypothyroidism,' 'prevalence,' and 'TSH' within the title and/or abstract. Relevant articles and related literature were selected for inclusion. RESULTS Estimates for the prevalence of SCH varied by sex, age, race/ethnicity, and geographic location (range, 0.4-16.9%). Higher rates of SCH were consistently reported in women (0.9-16.9%) and older individuals (2.7-16.9%). However, the ULN of TSH in those considered free of thyroid disease and not at risk increased progressively with age, suggesting that reports of SCH prevalence in elderly people may be overestimated. Multiple studies reported an increased risk of progression to overt hypothyroidism among individuals with elevated TSH and antithyroid antibodies. CONCLUSIONS Given the variable definition of SCH based on an inconsistent ULN for TSH, it is currently difficult to ascertain the true prevalence of SCH and to correctly label and treat patients with SCH; use of age-adjusted definitions may be considered when assessing prevalence. A diagnosis of SCH does not necessarily merit treatment, especially if TSH elevations are transient (i.e. not persistent for > 3-6 months) and the patient lacks other risk factors for developing overt hypothyroidism.
Collapse
Affiliation(s)
- J V Hennessey
- Division of Endocrinology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - R Espaillat
- Global Medical Affairs, AbbVie Inc., North Chicago, IL, USA
| |
Collapse
|
75
|
Dietrich JW, Müller P, Schiedat F, Schlömicher M, Strauch J, Chatzitomaris A, Klein HH, Mügge A, Köhrle J, Rijntjes E, Lehmphul I. Nonthyroidal Illness Syndrome in Cardiac Illness Involves Elevated Concentrations of 3,5-Diiodothyronine and Correlates with Atrial Remodeling. Eur Thyroid J 2015; 4:129-37. [PMID: 26279999 PMCID: PMC4521060 DOI: 10.1159/000381543] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/10/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Although hyperthyroidism predisposes to atrial fibrillation, previous trials have suggested decreased triiodothyronine (T3) concentrations to be associated with postoperative atrial fibrillation (POAF). Therapy with thyroid hormones (TH), however, did not reduce the risk of POAF. This study reevaluates the relation between thyroid hormone status, atrial electromechanical function and POAF. METHODS Thirty-nine patients with sinus rhythm and no history of atrial fibrillation or thyroid disease undergoing cardiac surgery were prospectively enrolled. Serum concentrations of thyrotropin, free (F) and total (T) thyroxine (T4) and T3, reverse (r)T3, 3-iodothyronamine (3-T1AM) and 3,5-diiodothyronine (3,5-T2) were measured preoperatively, complemented by evaluation of echocardiographic and electrophysiological parameters of cardiac function. Holter-ECG and telemetry were used to screen for POAF for 10 days following cardiac surgery. RESULTS Seven of 17 patients who developed POAF demonstrated nonthyroidal illness syndrome (NTIS; defined as low T3 and/or low T4 syndrome), compared to 2 of 22 (p < 0.05) patients who maintained sinus rhythm. In patients with POAF, serum FT3 concentrations were significantly decreased, but still within their reference ranges. 3,5-T2 concentrations directly correlated with rT3 concentrations and inversely correlated with FT3 concentrations. Furthermore, 3,5-T2 concentrations were significantly elevated in patients with NTIS and in subjects who eventually developed POAF. In multivariable logistic regression FT3, 3,5-T2, total atrial conduction time, left atrial volume index and Fas ligand were independent predictors of POAF. CONCLUSION This study confirms reduced FT3 concentrations in patients with POAF and is the first to report on elevated 3,5-T2 concentrations in cardiac NTIS. The pathogenesis of NTIS therefore seems to involve more differentiated allostatic mechanisms.
Collapse
Affiliation(s)
- Johannes W. Dietrich
- Department of Endocrinology and Diabetes, Medical Hospital I, Berlin, Germany
- *Dr. Johannes W. Dietrich, Department of Endocrinology and Diabetes, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bürkle-de-la-Camp-Platz 1, DE-44789 Bochum (Germany), E-Mail
| | - Patrick Müller
- Department of Cardiology and Angiology, Medical Hospital II, Berlin, Germany
- Heart Center Bad Neustadt, Clinic for Interventional Electrophysiology, Bad Neustadt an der Saale, Berlin, Germany
| | - Fabian Schiedat
- Department of Cardiology and Angiology, Medical Hospital II, Berlin, Germany
| | - Markus Schlömicher
- Department of Cardiac Surgery, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Berlin, Germany
| | - Justus Strauch
- Department of Cardiac Surgery, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Berlin, Germany
| | | | - Harald H. Klein
- Department of Endocrinology and Diabetes, Medical Hospital I, Berlin, Germany
| | - Andreas Mügge
- Department of Cardiology and Angiology, Medical Hospital II, Berlin, Germany
| | - Josef Köhrle
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Eddy Rijntjes
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ina Lehmphul
- Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
76
|
Chatzitomaris A, Scheeler M, Gotzmann M, Köditz R, Schildroth J, Knyhala KM, Nicolas V, Heyer C, Mügge A, Klein HH, Dietrich JW. Second degree AV block and severely impaired contractility in cardiac myxedema: a case report. Thyroid Res 2015; 8:6. [PMID: 26000037 PMCID: PMC4440534 DOI: 10.1186/s13044-015-0018-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 05/12/2015] [Indexed: 11/24/2022] Open
Abstract
The heart is a major target organ for thyroid hormone action. Severe overt hypothyroidism can result in diastolic hypertension, lowered cardiac output, impaired left ventricular contractility and diastolic relaxation, pericardial effusion and bradycardia. However, the function of the atrial pacemaker is usually normal and the degree by which the heart rate slows down is often modest. Here we report the case of a 20 year old male Caucasian with severe overt hypothyroidism. He presented with syncopation due to second degree atrioventricular block type Mobitz 2 and heart failure with reduced ejection fraction (38 %). Laboratory testing revealed a severe overt hypothyroidism with markedly elevated TSH (>100 mIU/L) and reduced fT3 and fT4 levels. The condition was caused by hypothyroid Graves’ disease (Graves’ disease with Hashimoto component). Although magnetic resonance imaging of the heart demonstrated decreased cardiac contractility and pericardial effusion, suggesting peri-myocarditis, plasma levels for BNP and troponin I were low. A possible infectious cause was unlikely, since testing for cardiotropic viruses was negative. The patient was treated with intravenous levothyroxine and after peripheral euthyroidism had been achieved, left ventricular ejection fraction returned to normal and pericardial effusion dissolved. Additionally, bradycardiac episodes abated, although intermittent second degree AV block was still occasionally present during the night. In conclusion, overt hypothyroidism may be associated by cardiac myxedema affecting both electrophysiology and contractility, observations that underscore the necessity of thyroid testing in different phenotypes of heart failure.
Collapse
Affiliation(s)
- Apostolos Chatzitomaris
- Department of Endocrinology and Diabetes, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, NRW Germany
| | - Michael Scheeler
- Department of Cardiology and Nephrology, Helios Klinikum Berlin-Buch, Berlin, Germany
| | - Michael Gotzmann
- Department of Cardiology and Angiology, Medical Hospital II, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, NRW Germany
| | - Roland Köditz
- Department of Endocrinology and Diabetes, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, NRW Germany
| | - Janice Schildroth
- Department of Endocrinology and Diabetes, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, NRW Germany
| | - Kathy Miriam Knyhala
- Department of Endocrinology and Diabetes, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, NRW Germany
| | - Volkmar Nicolas
- Institute of Diagnostic Radiology, Interventional Radiology and Nuclear Medicine, Bergmannsheil University Hospitals, Ruhr Univeristy of Bochum, Bochum, NRW Germany
| | - Christoph Heyer
- MVZ Radiologie - Institut für Kinderradiologie, Bochum, NRW Germany
| | - Andreas Mügge
- Department of Cardiology and Angiology, Medical Hospital II, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, NRW Germany
| | - Harald H Klein
- Department of Endocrinology and Diabetes, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, NRW Germany
| | - Johannes W Dietrich
- Department of Endocrinology and Diabetes, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, NRW Germany
| |
Collapse
|
77
|
Hoermann R, Midgley JEM, Larisch R, Dietrich JW. Homeostatic Control of the Thyroid-Pituitary Axis: Perspectives for Diagnosis and Treatment. Front Endocrinol (Lausanne) 2015; 6:177. [PMID: 26635726 PMCID: PMC4653296 DOI: 10.3389/fendo.2015.00177] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/04/2015] [Indexed: 12/20/2022] Open
Abstract
The long-held concept of a proportional negative feedback control between the thyroid and pituitary glands requires reconsideration in the light of more recent studies. Homeostatic equilibria depend on dynamic inter-relationships between thyroid hormones and pituitary thyrotropin (TSH). They display a high degree of individuality, thyroid-state-related hierarchy, and adaptive conditionality. Molecular mechanisms involve multiple feedback loops on several levels of organization, different time scales, and varying conditions of their optimum operation, including a proposed feedforward motif. This supports the concept of a dampened response and multistep regulation, making the interactions between TSH, FT4, and FT3 situational and mathematically more complex. As a homeostatically integrated parameter, TSH becomes neither normatively fixed nor a precise marker of euthyroidism. This is exemplified by the therapeutic situation with l-thyroxine (l-T4) where TSH levels defined for optimum health may not apply equivalently during treatment. In particular, an FT3-FT4 dissociation, discernible FT3-TSH disjoint, and conversion inefficiency have been recognized in l-T4-treated athyreotic patients. In addition to regulating T4 production, TSH appears to play an essential role in maintaining T3 homeostasis by directly controlling deiodinase activity. While still allowing for tissue-specific variation, this questions the currently assumed independence of the local T3 supply. Rather it integrates peripheral and central elements into an overarching control system. On l-T4 treatment, altered equilibria have been shown to give rise to lower circulating FT3 concentrations in the presence of normal serum TSH. While data on T3 in tissues are largely lacking in humans, rodent models suggest that the disequilibria may reflect widespread T3 deficiencies at the tissue level in various organs. As a consequence, the use of TSH, valuable though it is in many situations, should be scaled back to a supporting role that is more representative of its conditional interplay with peripheral thyroid hormones. This reopens the debate on the measurement of free thyroid hormones and encourages the identification of suitable biomarkers. Homeostatic principles conjoin all thyroid parameters into an adaptive context, demanding a more flexible interpretation in the accurate diagnosis and treatment of thyroid dysfunction.
Collapse
Affiliation(s)
- Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| | | | - Rolf Larisch
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| | - Johannes W. Dietrich
- Medical Department I, Endocrinology and Diabetology, Bergmannsheil University Hospitals, Ruhr University of Bochum, Bochum, Germany
- Ruhr Center for Rare Diseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
- *Correspondence: Johannes W. Dietrich,
| |
Collapse
|
78
|
Hoermann R, Midgley JEM, Giacobino A, Eckl WA, Wahl HG, Dietrich JW, Larisch R. Homeostatic equilibria between free thyroid hormones and pituitary thyrotropin are modulated by various influences including age, body mass index and treatment. Clin Endocrinol (Oxf) 2014; 81:907-15. [PMID: 24953754 DOI: 10.1111/cen.12527] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 06/06/2014] [Accepted: 06/16/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVE We examined the interrelationships of pituitary thyrotropin (TSH) with circulating thyroid hormones to determine whether they were expressed either invariably or conditionally and distinctively related to influences such as levothyroxine (L-T4) treatment. DESIGN AND METHODS This prospective study employing 1912 consecutive patients analyses the interacting equilibria of TSH and free triiodothyronine (FT3) and free thyroxine (FT4) in the circulation. RESULTS The complex interrelations between FT3, FT4 and TSH were modulated by age, body mass, thyroid volume, antibody status and L-T4 treatment. By group comparison and confirmation by more individual TSH-related regression, FT3 levels were significantly lower in L-T4-treated vs untreated nonhypothyroid autoimmune thyroiditis (median 4·6 vs 4·9 pm, P < 0·001), despite lower TSH (1·49 vs 2·93 mU/l, P < 0·001) and higher FT4 levels (16·8 vs 13·8 pm, P < 0·001) in the treated group. Compared with disease-free controls, the FT3-TSH relationship was significantly displaced in treated patients with carcinoma, with median TSH of 0·21 vs 1·63 (P < 0·001) at a comparable FT3 of 5·0 pm in the groups. Disparities were reflected by calculated deiodinase activity and remained significant even after accounting for confounding influences in a multivariable model. CONCLUSIONS TSH, FT4 and FT3 each have their individual, but also interlocking roles to play in defining the overall patterns of thyroidal expression, regulation and metabolic activity. Equilibria typical of the healthy state are not invariant, but profoundly altered, for example, by L-T4 treatment. Consequently, this suggests the revisitation of strategies for treatment optimization.
Collapse
Affiliation(s)
- Rudolf Hoermann
- Department of Nuclear Medicine, Klinikum Luedenscheid, Luedenscheid, Germany
| | | | | | | | | | | | | |
Collapse
|
79
|
Philippe J, Dibner C. Thyroid circadian timing: roles in physiology and thyroid malignancies. J Biol Rhythms 2014; 30:76-83. [PMID: 25411240 DOI: 10.1177/0748730414557634] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The circadian clock represents an anticipatory mechanism, well preserved in evolution. It has a critical impact on most aspects of the physiology of light-sensitive organisms. These rhythmic processes are governed by environmental cues (fluctuations in light intensity and temperature), an internal circadian timing system, and interactions between this timekeeping system and environmental signals. Endocrine body rhythms, including hypothalamic-pituitary-thyroid (HPT) axis rhythms, are tightly regulated by the circadian system. Although the circadian profiles of thyroid-releasing hormone (TRH), thyroid-stimulating hormone (TSH), thyroxine (T4), and triiodothyronine (T3) in blood have been well described, relatively few studies have analyzed molecular mechanisms governing the circadian regulation of HPT axis function. In this review, we will discuss the latest findings in the area of complex regulation of thyroid gland function by the circadian oscillator. We will also highlight the molecular makeup of the human thyroid oscillator as well as the potential link between thyroid malignant transformation and alterations in the clockwork.
Collapse
Affiliation(s)
- Jacques Philippe
- Department of Medical Specialties, Faculty of Medicine, University of Geneva, Geneva, Switzerland Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital of Geneva, Geneva, Switzerland
| | - Charna Dibner
- Department of Medical Specialties, Faculty of Medicine, University of Geneva, Geneva, Switzerland Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital of Geneva, Geneva, Switzerland
| |
Collapse
|
80
|
Dönitz J, Wingender E. EndoNet: an information resource about the intercellular signaling network. BMC SYSTEMS BIOLOGY 2014; 8:49. [PMID: 24758335 PMCID: PMC4017807 DOI: 10.1186/1752-0509-8-49] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 04/17/2014] [Indexed: 12/02/2022]
Abstract
BACKGROUND In multicellular organisms, an intercellular signaling network communicates information from the environment or distant tissues to defined target cells. Intercellular signaling (mostly mediated by hormones) can affect the metabolic state and the gene expression program of target cells, thereby coordinating development, homeostasis of the organism and its reactions to external stimuli. Knowledge of the components of the intercellular signaling (specifically: the endocrine) network and their relations is an important, though so far a largely neglected part of systems biology. DESCRIPTION EndoNet is an information resource about the endocrine system in human. The content of this database comprises information about the biological components of the endocrine system, like hormones, receptors and cells, as well as their relations like the secretion or the binding of a hormone to its receptor. All data within EndoNet have been manually annotated from the scientific literature. The web interface of EndoNet provides the content by a detailed page for each component. These pages list information about the component, links to external resources including literature as well as to related entities of EndoNet. The anatomical ontology Cytomer is used, in conjunction with the Ontology Based Answers service (OBA), to query and list related anatomical structures ranging from the level of individual cells to complete organs. While querying the web interface the user can add components to an individual network. This network, or the complete network stored in the database, can be further analyzed in a configurable pipeline or can be exported in various formats. CONCLUSION EndoNet is an important and unique information resource about the intercellular signaling network. Since the intercellular network is an integral part of systems biology, EndoNet provides essential information for analyzing interaction between different cellular networks.
Collapse
Affiliation(s)
- Jürgen Dönitz
- Institute of Bioinformatics, University Medical Center Göttingen, Goldschmidtstr. 1, 37077 Göttingen, Germany
| | - Edgar Wingender
- Institute of Bioinformatics, University Medical Center Göttingen, Goldschmidtstr. 1, 37077 Göttingen, Germany
| |
Collapse
|
81
|
Goede SL, Leow MKS, Smit JWA, Dietrich JW. A novel minimal mathematical model of the hypothalamus-pituitary-thyroid axis validated for individualized clinical applications. Math Biosci 2014; 249:1-7. [PMID: 24480737 DOI: 10.1016/j.mbs.2014.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 01/07/2014] [Accepted: 01/09/2014] [Indexed: 11/19/2022]
Abstract
The hypothalamus-pituitary-thyroid (HPT) axis represents a complex, non-linear thyroid hormone system in vertebrates governed by numerous variables. The common modeling approach until now aims at a comprehensive inclusion of all known physiological influences. In contrast, we develop a parsimonious mathematical model that integrates the hypothalamus-pituitary (HP) complex as an endocrinologic unit based on a parameterized negative exponential function between free thyroxine (FT4) as stimulus and thyrotropin (thyroid stimulating hormone, TSH) as response. Model validation with clinical data obtained from geographically different hospitals revealed a goodness-of-fit largely ranging between 90% < R² < 99%, each HP characteristic curve being uniquely defined for each individual akin to a fingerprint. Specifically, the HP model represents the afferent feedback limb of the HPT axis while the efferent limb is mathematically depicted by TSH input to the thyroid gland which responds by secreting T4 as its chief output. The complete HPT axis thus forms a closed loop system with negative feedback resulting in an equilibrium state or homeostasis under defined conditions illustrated by the intersection of the HP and thyroid response characteristics. In this treatise, we demonstrate how this mathematical approach facilitates homeostatic set points computation for personalized dosing of thyroid medications of patients to individualized euthyroid states.
Collapse
Affiliation(s)
- Simon L Goede
- Systems Research, Oterlekerweg 4, 1841 GP Stompetoren, The Netherlands.
| | - Melvin Khee-Shing Leow
- Singapore Institute for Clinical Sciences, Brenner Centre for Molecular Medicine, A∗STAR, Singapore; Tan Tock Seng Hospital, Singapore; National University of Singapore, Singapore; Duke-NUS Graduate Medical School Singapore, Singapore.
| | - Jan W A Smit
- Department of General Internal Medicine of Radboud University Nijmegen Medical Centre, Postbus 9101, 6500 HB Nijmegen, The Netherlands.
| | - Johannes W Dietrich
- Laboratory XU44, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum, D-44789 Bochum, NRW, Germany.
| |
Collapse
|
82
|
Do Thyroid-Stimulating Hormone, Body Weight, or Body Mass Index Serve as Adequate Markers to Guide Levothyroxine Dose Titration? J Am Coll Surg 2013; 217:752-3. [DOI: 10.1016/j.jamcollsurg.2013.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 06/17/2013] [Indexed: 11/19/2022]
|
83
|
Rochester JR. Bisphenol A and human health: a review of the literature. Reprod Toxicol 2013; 42:132-55. [PMID: 23994667 DOI: 10.1016/j.reprotox.2013.08.008] [Citation(s) in RCA: 1166] [Impact Index Per Article: 106.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 06/13/2013] [Accepted: 08/21/2013] [Indexed: 01/16/2023]
Abstract
There is growing evidence that bisphenol A (BPA) may adversely affect humans. BPA is an endocrine disruptor that has been shown to be harmful in laboratory animal studies. Until recently, there were relatively few epidemiological studies examining the relationship between BPA and health effects in humans. However, in the last year, the number of these studies has more than doubled. A comprehensive literature search found 91 studies linking BPA to human health; 53 published within the last year. This review outlines this body of literature, showing associations between BPA exposure and adverse perinatal, childhood, and adult health outcomes, including reproductive and developmental effects, metabolic disease, and other health effects. These studies encompass both prenatal and postnatal exposures, and include several study designs and population types. While it is difficult to make causal links with epidemiological studies, the growing human literature correlating environmental BPA exposure to adverse effects in humans, along with laboratory studies in many species including primates, provides increasing support that environmental BPA exposure can be harmful to humans, especially in regards to behavioral and other effects in children.
Collapse
Key Words
- 17-beta estradiol
- 8-OHdG
- 8-hydoxydeoxyguanosine
- A European population representative sample (Chianti, Italy)
- AGD
- ANA
- BADGE
- BASC-2
- BMI
- BPA
- BRIEF-P
- Behavior Rating Inventory of Executive Function-Preschool
- Behavioral Assessment System for Children
- Bisphenol A
- C-reactive protein
- CAD
- CBCL
- CHAMACOS
- CHD
- CMV
- CRP
- CVD
- Child Behavior Checklist
- DBP
- DHEAS
- Development
- E2
- ECN
- EFS
- EH
- EPIC-Norfolk Study
- ER
- Endocrine-disrupting chemicals
- Epidemiology
- FAI
- FDA
- FSH
- FT
- Food and Drug Administration
- HDL
- HOMES
- HRV
- HbA1c
- Human
- IL-6
- ISCI
- IVF
- InCHIANTI
- LDL
- LH
- MDA
- MGH
- MaGiCAD
- Massachusetts General Hospital (United States)
- Metabolic disease
- NECAT
- NHANES
- NICU Network Neurobehavioral Scale
- NNNS
- National Health and Nutrition Examination Survey (United States)
- OHAT
- Office of Health Assessment and Translation
- PCOS
- PFOA
- PFOS
- PIVUS
- Reproduction
- SBP
- SCE
- SFF
- SHBG
- SRS
- Social Responsiveness Scale
- T
- T3
- T4
- TDI
- TSH
- The Center for the Health Assessment of Mothers and Children of Salinas, Salina, CA
- The European Prospective Investigation into Cancer and Nutrition Cohort Study, consisting of over 500,000 people (Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Spain, Sweden and the United Kingdom)
- The Health Outcomes and Measures of the Environment Study (United States)
- The Metabolomics and Genomics in Coronary Artery Disease Study (Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Spain, Sweden and the United Kingdom)
- The New England Children's Amalgam Trial (United States)
- The Study for Future Families, USA
- The Vasculature in Uppsala Seniors Study (Uppsala, Sweden)
- Thyroid
- UCSF
- USEPA
- United Sates Environmental Protection Agency
- University of California, San Francisco
- VCL
- anogenital distance
- antinuclear antibodies
- bisGMA
- bisphenol A
- bisphenol A diglycidyl ether
- bisphenol A-glycidyl methacrylate
- body mass index
- cardiovascular disease
- coronary artery disease
- coronary heart disease
- curvilinear velocity (μm/s)
- cytomegalovirus
- dehydroepiandrosterone sulfate
- diastolic blood pressure
- embryo cell number
- embryo fragmentation score
- endometrial hyperplasia
- estrogen receptor
- follicle-stimulating hormone
- free androgen index (total T divided by SHBG)
- free testosterone
- hCG
- heart rate variability
- hemoglobin A1c
- high-density lipoprotein
- human chorionic gonadotropin
- in vitro fertilization
- interleukin-6
- intracytoplasmic sperm injection
- low-density lipoprotein
- luteinizing hormone
- malondialdehyde
- perfluorooctane sulfonate
- perfluorooctanoic acid
- polycystic ovary syndrome
- reverse transcription polymerase chain reaction
- rtPCR
- sex hormone binding globulin
- sister chromatid exchange
- systolic blood pressure
- thyroid stimulating hormone
- thyroxine
- tolerable daily intake
- total testosterone
- triidothyronine
Collapse
Affiliation(s)
- Johanna R Rochester
- The Endocrine Disruption Exchange (TEDX), P.O. Box 1407, Paonia, CO 81428, United States.
| |
Collapse
|
84
|
The role of thyroid hormone signaling in the prevention of digestive system cancers. Int J Mol Sci 2013; 14:16240-57. [PMID: 23924944 PMCID: PMC3759909 DOI: 10.3390/ijms140816240] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 07/25/2013] [Accepted: 07/30/2013] [Indexed: 11/17/2022] Open
Abstract
Thyroid hormones play a critical role in the growth and development of the alimentary tract in vertebrates. Their effects are mediated by nuclear receptors as well as the cell surface receptor integrin αVβ3. Systemic thyroid hormone levels are controlled via activation and deactivation by iodothyronine deiodinases in the liver and other tissues. Given that thyroid hormone signaling has been characterized as a major effector of digestive system growth and homeostasis, numerous investigations have examined its role in the occurrence and progression of cancers in various tissues of this organ system. The present review summarizes current findings regarding the effects of thyroid hormone signaling on cancers of the esophagus, stomach, liver, pancreas, and colon. Particular attention is given to the roles of different thyroid hormone receptor isoforms, the novel integrin αVβ3 receptor, and thyroid hormone-related nutrients as possible protective agents and therapeutic targets. Future investigations geared towards a better understanding of thyroid hormone signaling in digestive system cancers may provide preventive or therapeutic strategies to diminish risk, improve outcome and avert recurrence in afflicted individuals.
Collapse
|