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Stancu AM, Pop O, Purice M, Badiu C. Lipid Profile Evolution in Graves' Disease Treated with Titration Regimen of Anti-Thyroid Drugs Versus Block and Replace Regimen. Horm Metab Res 2024. [PMID: 38565183 DOI: 10.1055/a-2281-0911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The aim was to compare the lipid profile of patients with GD treated with anti-thyroid drugs (ATDs) using a titration regimen versus a block and replace regimen. This is an 18-month prospective observational study. In this study were included 149 medically treated GD patients, aged+>+18 years. Pregnant women and patients treated with radioactive iodine therapy or partial/total thyroidectomy were excluded. Patients were divided into 2 subgroups: titration (A) and block and replace (B) therapy, according to the ATD regimen used. Thyroid and metabolic profile was measured at baseline and at least one visit during medical treatment. The whole group included 122 (81.87%) females (F) and 27 (18.12%) males (M), ratio F:M=4.5:1. As expected, at the time of diagnosis, thyrotoxic patients were with normal lipid profile. During medical treatment, in patients who achieved euthyroidism, the cholesterol levels increased as follows: in subgroup A: by 52.9 mg/dl (95% CI: 26.4-79.3), p<0.001 for total cholesterol (T-C), by 33.3 mg/dl (95% CI: 10.3-56.3), p=0.007 for low-density lipoprotein cholesterol (LDL-C) and by 11.44 mg/dl (95% CI: 3.08-19.79), p=0.009 for high-density lipoprotein cholesterol (HDL-C); in subgroup B T-C increased by 45.1 mg/dl (95% CI: 22.2-68), p<0.001 and for LDL-C by 33.57 mg/dl (95% CI: 12.72-54.42), p=0.003. No statistically significant increase in triglyceride levels was determined. Medical treatment of hyperthyroidism due to Graves' disease increased cholesterol levels regardless of the ATD regimen used.
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Affiliation(s)
- Ana-Maria Stancu
- Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Endocrinology IV, "C.I. Parhon" National Institute of Endocrinology, Bucharest, Romania
| | - Oana Pop
- Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
| | - Mariana Purice
- Research Department, "C.I. Parhon" National Institute of Endocrinology, Bucharest, Romania
| | - Corin Badiu
- Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
- Endocrinology IV, "C.I. Parhon" National Institute of Endocrinology, Bucharest, Romania
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Lee YW, Yang TT, Lin YY, Hsieh YS. Elevated Free Thyroxine Levels Might Alter the Effect of the Lipid Profile on Insulin Resistance in Type 2 Diabetes Mellitus. Diagnostics (Basel) 2023; 13:2656. [PMID: 37627914 PMCID: PMC10453194 DOI: 10.3390/diagnostics13162656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/09/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
Previous studies have shown that hyperthyroidism is associated with heightened insulin resistance and dyslipidemia. Therefore, in this study, we aim to explore the relationship between elevated thyroid hormone levels and the lipid profile in insulin resistance in patients with type 2 diabetes mellitus (T2DM) with hyperthyroidism. A total of 177 participants were included and grouped according to diagnosis. The serum test results demonstrated that free thyroxine (FT4) increased the insulin resistance index (HOMA-IR) by positively correlating with triglyceride (TG) levels (p = 0.005, r2 = 0.35). In patients with T2DM with hyperthyroidism, the decreasing high-density lipoprotein levels showed an association with HOMA-IR (p = 0.005). Among all the patients, with different levels of FT4, the areas under the ROC curve (AUCs) of the TG level, TG/high-density lipoprotein ratio, and HOMA-IR were 0.620 (95% CI: 0.536 to 0.698), 0.614 (95% CI: 0.530 to 0.692), and 0.722 (95% CI: 0.645 to 0.791), respectively. Our results suggest that elevated FT4 levels due to hyperthyroidism could alter the association with the lipid profile and insulin resistance in patients with T2DM. We also suggest that among all the included patients with T2DM, irrespective of the presence of hyperthyroidism, FT4 levels are positively correlated with insulin resistance.
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Affiliation(s)
- Yi-Wei Lee
- Department of Internal Medicine, Taipei Medical University Hospital, Taipei City 11030, Taiwan
| | - Ting-Teng Yang
- Department of Internal Medicine, Taipei Medical University Hospital, Taipei City 11030, Taiwan
| | - Yan-Yu Lin
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Taipei Medical University Hospital, Taipei City 11030, Taiwan
| | - Yu-Shan Hsieh
- School of Nursing, National Taipei University of Nursing and Health Sciences, Taipei City 11230, Taiwan
- Department of Research, Taipei Medical University Hospital, Taipei City 11030, Taiwan
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3
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Post A, Garcia E, Gruppen EG, Kremer D, Connelly MA, Bakker SJL, Dullaart RPF. Higher Free Triiodothyronine Is Associated With Higher HDL Particle Concentration and Smaller HDL Particle Size. J Clin Endocrinol Metab 2022; 107:e1807-e1815. [PMID: 35106588 PMCID: PMC9016450 DOI: 10.1210/clinem/dgac044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Indexed: 11/23/2022]
Abstract
CONTEXT Thyroid function status has effects on the development of atherosclerotic cardiovascular disease by affecting lipid metabolism, but associations of high-density lipoprotein (HDL) particle concentrations and subfractions with thyroid hormone levels within the reference range remain elusive. OBJECTIVE The aim of the present study was to determine the associations of free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) levels with HDL particle characteristics in euthyroid individuals. METHODS This cross-sectional study on the associations of thyroid hormones with HDL particle concentrations, HDL subfractions, and HDL particle size included 5844 euthyroid individuals (FT3, FT4, and TSH levels within the reference range and no medication use affecting thyroid function), participating in the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) study. HDL particles and subfractions were measured by nuclear magnetic resonance using an optimized version of the NMR LipoProfile Test (LP4). RESULTS In multivariable linear regression analyses, FT3 was positively associated with total HDL particle concentration (std.β = 0.14; P < 0.001) and with small (std.β = 0.13; P < 0.001) and medium-sized HDL particles (std.β = 0.05; P = 0.001). Conversely, FT3 was inversely associated with large HDL particles (std.β = -0.07; P < 0.001) and with HDL particle size (std.β = -0.08; P < 0.001). Such associations with FT4 or reciprocally with TSH were less pronounced or nonsignificant. CONCLUSION In euthyroid individuals, higher FT3 is cross-sectionally associated with higher total HDL particle concentration and with lower HDL particle size. These associations may be relevant to better understand the role of HDL in thyroid function-associated atherosclerotic cardiovascular disease.
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Affiliation(s)
- Adrian Post
- Department of Internal Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands
| | - Erwin Garcia
- Laboratory Corporation of America Holdings (Labcorp), Morrisville, NC 27560, USA
| | - Eke G Gruppen
- Department of Internal Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands
| | - Daan Kremer
- Department of Internal Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands
| | - Margery A Connelly
- Laboratory Corporation of America Holdings (Labcorp), Morrisville, NC 27560, USA
| | - Stephan J L Bakker
- Department of Internal Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands
| | - Robin P F Dullaart
- Department of Internal Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands
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Alteration of Serum Proteome in Levo-Thyroxine-Euthyroid Thyroidectomized Patients. J Clin Med 2022; 11:jcm11061676. [PMID: 35330001 PMCID: PMC8951767 DOI: 10.3390/jcm11061676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 11/16/2022] Open
Abstract
The monotherapy with levo-thyroxine (LT4) is the treatment of choice for patients with hypothyroidism after thyroidectomy. However, many athyreotic LT4-treated patients with thyroid hormones in the physiological range experience hypothyroid-like symptoms, showing post-operative, statistically significant lower FT3 levels with respect to that before total thyroidectomy. Since we hypothesized that the lower plasmatic FT3 levels observed in this subgroup could be associated with tissue hypothyroidism, here we compared, by a preliminary proteomic analysis, eight sera of patients with reduced post-surgical FT3 to eight sera from patients with FT3 levels similar to pre-surgery levels, and six healthy controls. Proteomic analysis highlights a different serum protein profile among the considered conditions. By enrichment analysis, differential proteins are involved in coagulation processes (PLMN-1.61, -1.98 in reduced vs. stable FT3, p < 0.02; A1AT fragmentation), complement system activation (CFAH + 1.83, CFAB + 1.5, C1Qb + 1.6, C1S + 7.79 in reduced vs. stable FT3, p < 0.01) and in lipoprotein particles remodeling (APOAI fragmentation; APOAIV + 2.13, p < 0.003), potentially leading to a pro-inflammatory response. This study suggests that LT4 replacement therapy might restore biochemical euthyroid conditions in thyroidectomized patients, but in some cases without re-establishing body tissue euthyroidism. Since our results, this condition is reflected by the serum protein profile.
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Kyriacou A, Kyriacou A, Makris KC, Syed AA, Perros P. Weight gain following treatment of hyperthyroidism-A forgotten tale. Clin Obes 2019; 9:e12328. [PMID: 31267667 DOI: 10.1111/cob.12328] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/12/2019] [Accepted: 05/28/2019] [Indexed: 12/14/2022]
Abstract
Hyperthyroidism causes weight loss in the majority, but its effect is variable and 10% of patients gain weight. Its treatment usually leads to weight gain and some studies have reported an excess weight regain. However, there is considerable inter-individual variability and a differential effect on body weight by different treatments, with some studies reporting more weight increase with radioiodine, and perhaps surgery, compared with anti-thyroid drugs. The excess weight regain may relate to treatment-induced hypothyroidism. Furthermore, the transition from hyperthyroidism to euthyroidism may unmask, or exacerbate, the predisposition that some patients have towards obesity. Other risk factors commonly implicated for such weight increase include the severity of thyrotoxicosis at presentation and underlying Graves' disease. Conflicting data exist whether lean body mass or fat mass or both are increased post-therapy and whether such increments occur concurrently or in a sequential manner; this merits clarification. In any case, clinicians need to counsel their patients regarding this issue at presentation. Limited data on the effect of dietary interventions on weight changes with treatment of hyperthyroidism are encouraging in that they cause significantly lesser weight gain compared to standard care. More research is indicated on the impact of the treatment of hyperthyroidism on various anthropometric indices and the predisposing factors for any excessive weight gain. Regarding the impact of dietary management or other weight loss interventions, there is a need for well-designed and, ideally, controlled intervention studies.
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Affiliation(s)
- Angelos Kyriacou
- Cyprus International Institute for Environmental and Public Health, Cyprus University of Technology, Limassol, Cyprus
- Department of Endocrinology & Dietetics, CEDM Centre of Endocrinology, Diabetes & Metabolism, Limassol, Cyprus
- Diabetes, Endocrinology & Obesity Medicine, Salford Royal NHS Foundation Trust, Salford, UK
| | - Alexis Kyriacou
- Department of Endocrinology & Dietetics, CEDM Centre of Endocrinology, Diabetes & Metabolism, Limassol, Cyprus
- School of Health Sciences, University of Stirling, Stirling, UK
| | - Konstantinos C Makris
- Cyprus International Institute for Environmental and Public Health, Cyprus University of Technology, Limassol, Cyprus
| | - Akheel A Syed
- Diabetes, Endocrinology & Obesity Medicine, Salford Royal NHS Foundation Trust, Salford, UK
- Division of Diabetes, Endocrinology & Gastroenterology, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester, UK
| | - Petros Perros
- Department of Endocrinology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Institute of Human Genetics, University of Newcastle, Newcastle upon Tyne, UK
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Hoshi RA, Andreão RV, Santos IS, Dantas EM, Mill JG, Lotufo PA, Bensenor IM. Linear and nonlinear analyses of heart rate variability following orthostatism in subclinical hypothyroidism. Medicine (Baltimore) 2019; 98:e14140. [PMID: 30681577 PMCID: PMC6358401 DOI: 10.1097/md.0000000000014140] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Subclinical hypothyroidism (SCHypo) is associated with autonomic disturbances that can interfere in physiological responses. This study was designed to evaluate linear and nonlinear variables of heart rate variability (HRV) following postural change, comparing subjects with SCHypo to euthyroid subjects.HRV analyses were performed in 5-minute time series collected in the supine and standing positions from a subsample of 855 participants of the ELSA-Brasil study. The cardiac autonomic nervous function was evaluated by linear time and frequency domain analyses (SDNN, RMSSD, LFms, HFms, and LF/HF ratio) as well as by nonlinear symbolic dynamics (0, 1, and 2 V).After exclusions, 509 (92.0%) euthyroid and 44 (8.0%) SCHypo participants were eligible for analyses. At the baseline supine rest measurement, the 0 V symbolic pattern was higher (27.7 vs 25.4, P = .02) and 2 V was lower (18.0 vs 22.9, P = .02) than in the euthyroid group. Comparing the variation between positions, the 0 V pattern showed a lower delta in SCHypo than in Euthyroid subjects (8.0 vs 10.8%, P = .04).SCHypo presented lower sympathetic and parasympathetic tonus at rest and a blunted sympathetic response to active postural change, marked by reduced variation in the 0 V of symbolic analysis (SA). Additionally, it is suggested that SA of HR dynamics is an alternative and, possibly, a more sensitive method for cardiac autonomic assessment following orthostatism in this population.
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Affiliation(s)
- Rosangela A. Hoshi
- Center for Clinical and Epidemiologic Study for Research, University Hospital, Sao Paulo, SP
| | - Rodrigo V. Andreão
- Department of Electrical Engineering, Federal Institute of Espirito Santo, Vitoria, ES
| | - Itamar S. Santos
- Center for Clinical and Epidemiologic Study for Research, University Hospital, Sao Paulo, SP
| | - Eduardo M. Dantas
- Collegiate of Biological Sciences, Federal University of Vale do Sao Francisco, Petrolina–PE, Brazil
| | - José Geraldo Mill
- Department of Physiological Sciences, Federal University of Espirito Santo, Center of Health Sciences, Vitoria, ES, Brazil
| | - Paulo A. Lotufo
- Center for Clinical and Epidemiologic Study for Research, University Hospital, Sao Paulo, SP
| | - Isabela M. Bensenor
- Center for Clinical and Epidemiologic Study for Research, University Hospital, Sao Paulo, SP
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Shahsavari D, Zoll B. De novo coronary artery disease in graves’ disease. coincidence? J Community Hosp Intern Med Perspect 2018; 8:292-295. [PMID: 30357055 PMCID: PMC6197004 DOI: 10.1080/20009666.2018.1514934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 08/17/2018] [Indexed: 11/02/2022] Open
Abstract
Hyperthyroidism is associated with increased risk of cardiovascular conditions. We report a case of a 50-year-old woman with no prior cardiac history who presented to the emergency department with shortness of breath, chest pain, lower extremity swelling, and generalized fatigue. She was found to have Graves’ Disease (GD) and extensive coronary artery disease (CAD), suggesting the possibility of increased risk of de novo CAD in patients with GD in the absence of other risk factors.
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Affiliation(s)
- Dariush Shahsavari
- Section of Hospital Medicine, Department of Medicine, Lewis Katz School of Medicineat Temple University, Philadelphia, PA, USA
| | - Bryan Zoll
- Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
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8
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Affiliation(s)
- Jane Freeston
- Department of Rheumatology, Harrogate District Hospital, Harrogate, North Yorks, UK.
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9
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Association between thyroid function and lipid profiles, apolipoproteins, and high-density lipoprotein function. J Clin Lipidol 2017; 11:1347-1353. [DOI: 10.1016/j.jacl.2017.08.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/17/2017] [Accepted: 08/24/2017] [Indexed: 01/25/2023]
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10
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Al-Majdoub M, Lantz M, Spégel P. Treatment of Swedish Patients with Graves' Hyperthyroidism Is Associated with Changes in Acylcarnitine Levels. Thyroid 2017; 27:1109-1117. [PMID: 28699427 DOI: 10.1089/thy.2017.0218] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Hyperthyroidism is associated with alterations in metabolism that are currently only partially understood. The objective of the study was to investigate changes in metabolism associated with reinstatement of euthyroidism in Swedish patients. METHODS Eighty metabolites in plasma were profiled from 10 subjects with Graves' disease (GD) at baseline and after 9 and 15 months of treatment to reinstate euthyroidism. Thyroid parameters, thyrotropin (TSH), TSH receptor antibodies, free triiodothyronine, and free thyroxine were followed. Main findings were validated in plasma from 20 subjects with GD at baseline and at three, six, and nine months. The study was conducted at the endocrinology clinic in Malmö, Sweden. RESULTS Euthyroidism was reinstated at three months, and thyroid status did not change further during the 15-month follow-up. This was paralleled by altered levels of 9/19 detected acylcarnitines (p < 0.05 after adjustment for multiple testing). Levels of short-chain acylcarnitines were decreased, intermediate-chain acylcarnitines elevated, and long-chain acylcarnitines unaltered. CONCLUSIONS GD and treatment of the disease is associated with pronounced acyl chain length-dependent alterations in acylcarnitine levels. These changes may be impacted by ethnicity and or dietary differences.
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Affiliation(s)
- Mahmoud Al-Majdoub
- 1 Unit of Molecular Metabolism, Department of Clinical Sciences in Malmö Lund University , Malmö, Sweden
| | - Mikael Lantz
- 1 Unit of Molecular Metabolism, Department of Clinical Sciences in Malmö Lund University , Malmö, Sweden
- 2 Department of Endocrinology, Skåne University Hospital , Malmö, Sweden
| | - Peter Spégel
- 1 Unit of Molecular Metabolism, Department of Clinical Sciences in Malmö Lund University , Malmö, Sweden
- 3 Centre for Analysis and Synthesis, Department of Chemistry, Lund University , Malmö, Sweden
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Pietzner M, Engelmann B, Kacprowski T, Golchert J, Dirk AL, Hammer E, Iwen KA, Nauck M, Wallaschofski H, Führer D, Münte TF, Friedrich N, Völker U, Homuth G, Brabant G. Plasma proteome and metabolome characterization of an experimental human thyrotoxicosis model. BMC Med 2017; 15:6. [PMID: 28065164 PMCID: PMC5220622 DOI: 10.1186/s12916-016-0770-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 12/15/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Determinations of thyrotropin (TSH) and free thyroxine (FT4) represent the gold standard in evaluation of thyroid function. To screen for novel peripheral biomarkers of thyroid function and to characterize FT4-associated physiological signatures in human plasma we used an untargeted OMICS approach in a thyrotoxicosis model. METHODS A sample of 16 healthy young men were treated with levothyroxine for 8 weeks and plasma was sampled before the intake was started as well as at two points during treatment and after its completion, respectively. Mass spectrometry-derived metabolite and protein levels were related to FT4 serum concentrations using mixed-effect linear regression models in a robust setting. To compile a molecular signature discriminating between thyrotoxicosis and euthyroidism, a random forest was trained and validated in a two-stage cross-validation procedure. RESULTS Despite the absence of obvious clinical symptoms, mass spectrometry analyses detected 65 metabolites and 63 proteins exhibiting significant associations with serum FT4. A subset of 15 molecules allowed a robust and good prediction of thyroid hormone function (AUC = 0.86) without prior information on TSH or FT4. Main FT4-associated signatures indicated increased resting energy expenditure, augmented defense against systemic oxidative stress, decreased lipoprotein particle levels, and increased levels of complement system proteins and coagulation factors. Further association findings question the reliability of kidney function assessment under hyperthyroid conditions and suggest a link between hyperthyroidism and cardiovascular diseases via increased dimethylarginine levels. CONCLUSION Our results emphasize the power of untargeted OMICs approaches to detect novel pathways of thyroid hormone action. Furthermore, beyond TSH and FT4, we demonstrated the potential of such analyses to identify new molecular signatures for diagnosis and treatment of thyroid disorders. This study was registered at the German Clinical Trials Register (DRKS) [DRKS00011275] on the 16th of November 2016.
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Affiliation(s)
- Maik Pietzner
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
| | - Beatrice Engelmann
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
| | - Tim Kacprowski
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
| | - Janine Golchert
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
| | - Anna-Luise Dirk
- Medical Clinic I, University of Lübeck, Experimental and Clinical Endocrinology, Ratzeburger Allee 160, Zentralklinikum (Haus 40), 23538 Lübeck, Germany
| | - Elke Hammer
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
| | - K. Alexander Iwen
- Medical Clinic I, University of Lübeck, Experimental and Clinical Endocrinology, Ratzeburger Allee 160, Zentralklinikum (Haus 40), 23538 Lübeck, Germany
| | - Matthias Nauck
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
| | - Henri Wallaschofski
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
- Private Practice Endocrinology, Krämpferstraße 6, 99094 Erfurt, Germany
| | - Dagmar Führer
- Department of Endocrinology and Metabolism, University Hospital Essen, University Duisburg-Essen, Hufelandstraße 55, 45122 Essen, Germany
| | - Thomas F. Münte
- Department of Neurology, University of Lübeck, Ratzeburger Allee 169, 23538 Lübeck, Germany
| | - Nele Friedrich
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Research Centre for Prevention and Health, Glostrup University Hospital, Nordre Ringvej 57, 2600 Glostrup, Denmark
| | - Uwe Völker
- DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
- ZIK-FunGene (Zentrum für Innovationskompetenz - Funktionelle Genomforschung), Greifswald, Germany
| | - Georg Homuth
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine and Ernst-Moritz-Arndt University Greifswald, Friedrich-Ludwig-Jahn-Straße 15a, D-17475 Greifswald, Germany
- ZIK-FunGene (Zentrum für Innovationskompetenz - Funktionelle Genomforschung), Greifswald, Germany
| | - Georg Brabant
- Medical Clinic I, University of Lübeck, Experimental and Clinical Endocrinology, Ratzeburger Allee 160, Zentralklinikum (Haus 40), 23538 Lübeck, Germany
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McGowan A, Widdowson WM, O'Regan A, Young IS, Boran G, McEneny J, Gibney J. Postprandial Studies Uncover Differing Effects on HDL Particles of Overt and Subclinical Hypothyroidism. Thyroid 2016; 26:356-64. [PMID: 26800752 DOI: 10.1089/thy.2015.0443] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Overt hypothyroidism (OH) is associated with abnormal lipid metabolism and endothelial dysfunction under fasting conditions. The balance of evidence suggests similar but less marked abnormalities in subclinical hypothyroidism (SCH). There are few data regarding the metabolic and vascular effects of OH or SCH under postprandial conditions. METHODS This was a cross-sectional study, carried out in a teaching hospital. Subjects with OH (n = 21), SCH (n = 28), and controls (n = 44) matched for age, sex, and body mass index (BMI) were studied under fasting and postprandial conditions. Postprandial lipid metabolism with particular emphasis on intestinally derived lipoproteins, HDL cholesterol (HDL), and endothelial function were compared in subjects with OH and SCH who were matched for age, sex, and BMI. Apolipoprotein B48 (Apo B48), a measure of intestinally derived lipoprotein, was measured by enzyme-linked immunosorbent assay. HDL was subfractionated into HDL2 and HDL3 by rapid ultracentrifugation. Functional aspects of HDL were determined by monitoring the activities of cholesteryl-ester-transfer-protein (CETP) and lecithin-cholesterol-acyl-transferase (LCAT). Systemic and HDL-associated inflammation was assessed by measuring serum-amyloid-A (SAA) levels. Endothelial function was assessed by flow-mediated dilatation (FMD) of the brachial artery in response to hyperemia of the forearm. RESULTS There were no significant between-group differences in LDL cholesterol or triglyceride concentration. Peak Apo B48 levels were greater in OH (p < 0.001) and SCH (p < 0.05) compared with control subjects. HDL area under the curve (AUC) was lower postprandially in SCH (p < 0.001) but not OH compared with control subjects. HDL2- and HDL3-associated CETP AUC was lower only in OH (p < 0.005) compared with controls. FMD was reduced in OH (p < 0.05) compared with SCH and controls postprandially. CONCLUSION Postprandial lipoprotein and vascular abnormalities differ between OH and SCH. Although both are characterized by increased intestinally derived lipoprotein particles, HDL is reduced only in SCH. Maintained HDL in OH probably reflects reduced CETP activity, which was not observed in SCH. Postprandial endothelial dysfunction is abnormal only in OH, and this effect does not appear to reflect increased inflammation.
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Affiliation(s)
- Anne McGowan
- 1 Department of Endocrinology, Tallaght Hospital , Dublin, Ireland
| | | | - Anna O'Regan
- 2 Centre for Public Health, Queen's University Belfast , Belfast, United Kingdom
| | - Ian S Young
- 2 Centre for Public Health, Queen's University Belfast , Belfast, United Kingdom
| | - Gerard Boran
- 3 Department of Chemical Pathology, Tallaght Hospital , Dublin, Ireland
| | - Jane McEneny
- 2 Centre for Public Health, Queen's University Belfast , Belfast, United Kingdom
| | - James Gibney
- 1 Department of Endocrinology, Tallaght Hospital , Dublin, Ireland
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13
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Abstract
BACKGROUND Hypothyroidism is associated with an increased risk of coronary artery disease, beyond that which can be explained by its association with conventional cardiovascular risk factors. Coronary endothelial dysfunction precedes atherosclerosis, has been linked to adverse cardiovascular events, and may account for some of the increased risk in patients with hypothyroidism. The aim of this study was to determine whether there is an association between epicardial and microvascular coronary endothelial dysfunction and hypothyroidism. METHODS AND RESULTS In 1388 patients (mean age 50.5 [12.3] years, 34% male) presenting with stable chest pain to Mayo Clinic, Rochester, MN for diagnostic coronary angiography, and who were found to have nonobstructive coronary artery disease (<40% stenosis), we invasively assessed coronary artery endothelial-dependent microvascular and epicardial function by evaluating changes in coronary blood flow (% Δ CBF Ach) and diameter (% Δ CAD Ach), respectively, in response to intracoronary infusions of acetylcholine. Patients were divided into 2 groups: hypothyroidism, defined as a documented history of hypothyroidism or a thyroid-stimulating hormone (TSH) >10.0 mU/mL, n=188, and euthyroidism, defined as an absence of a history of hypothyroidism in the clinical record and/or 0.3<TSH≤10.0 mU/mL, n=1200. Subjects with a history of hypothyroidism had a significantly lower % Δ CBF Ach (48.26 [80.66] versus 64.58 [128.30]) compared to patients with euthyroidism, while the % Δ CAD Ach did not vary significantly between groups. After adjusting for covariates, females with hypothyroidism still had a significantly lower % Δ CBF Ach (estimated difference in % Δ CBF Ach [SE]: -16.79 [8.18]). CONCLUSIONS Hypothyroidism in women is associated with microvascular endothelial dysfunction, even after adjusting for confounders, and may explain some of the increased risk of cardiovascular disease in these patients.
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Affiliation(s)
- Jaskanwal D Sara
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (J.D.S., M.Z., A.L.)
| | - Ming Zhang
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (J.D.S., M.Z., A.L.)
| | - Hossein Gharib
- Division of Endocrinology and Metabolic Disease, Mayo Clinic, Rochester, MN (H.G.)
| | - Lilach O Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN (L.O.L.)
| | - Amir Lerman
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (J.D.S., M.Z., A.L.)
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Erem C, Suleyman AK, Civan N, Mentese A, Nuhoglu İ, Uzun A, Ersoz HO, Deger O. Ischemia-modified albümin and malondialdehyde levels in patients with overt and subclinical hyperthyroidism: effects of treatment on oxidative stress. Endocr J 2015; 62:493-501. [PMID: 25843331 DOI: 10.1507/endocrj.ej14-0542] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The main purpose of this study was to evaluate the levels of ischemia-modified albumin (IMA) and malondialdehyde (MDA) in patients with OHyper and SHyper, to assess the effects of antithyroid drug (ATD) therapy on the oxidative stress (OS) parameters. Forty-five untreated patients with overt hyperthyroidism (OHyper), 20 untreated patients with subclinical hyperthyroidism (SHyper) and 30 age-and sex-matched healthy controls were prospectively included in the study. Biochemical and hormonal parameters were evaluated in all patients before and after treatment. Compared with the control subjects, the levels of MDA, glucose and TG were significantly increased in patients with SHyper (p<0.05), whereas LDL-C levels were significantly decreased (p<0.01). Patients with OHyper showed significantly elevated MDA and glucose levels (p<0.001) and significantly decreased LDL-C and HDL-C levels compared with the controls (p<0.01). In patients with Graves' disease, serum TSH levels were inversely correlated with plasma MDA levels (r: -0.42, p<0.05). Plasma MDA levels significantly decreased and levels of TC, LDL-C and HDL-C significantly increased in the groups of OHyper and SHyper after treatment. Serum IMA levels did not significantly change at baseline and with the therapy in all subjects. In conclusion, increased MDA levels in both patient groups represent increased lipid peroxidation which might play an important role in the pathogenesis of the atherosclerosis in these patients. Increased oxidative stress in patients with SHyper and OHyper could be improved by ATD therapy. Also, MDA can be used as a reliable marker of OS and oxidative damage, while IMA is considered to be inappropriate.
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Affiliation(s)
- Cihangir Erem
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Karadeniz Technical University Faculty of Medicine, 61080 Trabzon, Turkey
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15
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Hashimoto K, Ishida E, Miura A, Ozawa A, Shibusawa N, Satoh T, Okada S, Yamada M, Mori M. Human stearoyl-CoA desaturase 1 (SCD-1) gene expression is negatively regulated by thyroid hormone without direct binding of thyroid hormone receptor to the gene promoter. Endocrinology 2013; 154:537-49. [PMID: 23221600 DOI: 10.1210/en.2012-1559] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Stearoyl-CoA desaturase-1 (SCD-1) plays a pivotal role in an increase of triglyceride by an excess of dietary carbohydrate intake. Dietary carbohydrates increase SCD-1 gene expression in liver by sterol response element binding protein (SREBP)-1c-dependent and SREBP-1c -independent pathways. Previous report demonstrated that thyroid hormone (TH) negatively regulates mouse SCD-1 gene promoter before SREBP-1c was revealed. We reported that TH negatively regulates SREBP-1c recently. Therefore, in the current study, we examined whether and how TH regulates human SCD-1 gene expression and evaluated SREBP-1c effect on the negative regulation. Luciferase assays revealed that TH suppresses both mouse and human SCD-1 gene promoter activity. In SREBP-1 knockdown HepG2 cells, TH still suppresses SCD-1 gene promoter activity, and it also exerted the negative regulation under cotransfection of a small amount of SREBP-1c. These data indicated that SREBP-1c does not play the decisive role for the negative regulation by TH. The responsible region for the negative regulation in human SCD-1 gene promoter turned out to be between -124 and -92 bp, referred to as site A. Chromatin immunoprecipitation assays demonstrated that TH receptor-β is recruited to the region upon T(3) administration, although TR-β does not bind directly to site A. In conclusion, TH negatively regulates human SCD-1 gene expression in without direct binding of the TH receptor to the SCD-1 gene promoter.
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16
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Lipid abnormalities and cardiometabolic risk in patients with overt and subclinical thyroid disease. J Lipids 2011; 2011:575840. [PMID: 21789282 PMCID: PMC3140027 DOI: 10.1155/2011/575840] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 05/17/2011] [Accepted: 05/17/2011] [Indexed: 02/03/2023] Open
Abstract
Dyslipidemia is a common finding in patients with thyroid disease, explained by the adverse effects of thyroid hormones in almost all steps of lipid metabolism. Not only overt but also subclinical hypo- and hyperthyroidism, through different mechanisms, are associated with lipid alterations, mainly concerning total and LDL cholesterol and less often HDL cholesterol, triglycerides, lipoprotein (a), apolipoprotein A1, and apolipoprotein B. In addition to quantitative, qualitative alterations of lipids have been also reported, including atherogenic and oxidized LDL and HDL particles. In thyroid disease, dyslipidemia coexists with various metabolic abnormalities and induce insulin resistance and oxidative stress via a vice-vicious cycle. The above associations in combination with the thyroid hormone induced hemodynamic alterations, might explain the increased risk of coronary artery disease, cerebral ischemia risk, and angina pectoris in older, and possibly ischemic stroke in younger patients with overt or subclinical hyperthyroidism.
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17
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Hashimoto K, Mori M. Crosstalk of thyroid hormone receptor and liver X receptor in lipid metabolism and beyond [Review]. Endocr J 2011; 58:921-30. [PMID: 21908933 DOI: 10.1507/endocrj.ej11-0114] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Thyroid hormone receptors (TRs) and liver X receptors (LXRs) are members of the nuclear receptor superfamily. Although LXRs and TRs belong to two distinct receptor subgroups with respect to ligand-binding affinity, the two receptor systems show similarity with respect to molecular mechanism, target genes, and physiological roles. Since both TRs and LXRs play an important role in metabolic regulation, form heterodimers with retinoid X receptors (RXRs), and bind to direct repeat-4 (DR-4) with identical geometry and polarity, crosstalk between these two receptors has been reported, especially on lipid metabolism-related genes. Recently, several types of crosstalk between TRs and LXRs have been identified and crosstalk has also been observed in other physiological systems such as central nervous system rather than lipid metabolism. In this review, recent advances in elucidating the molecular mechanisms of the crosstalk between these two nuclear receptors are discussed, with the aim of finding a perspective on unknown roles of TRs and LXRs.
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Affiliation(s)
- Koshi Hashimoto
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Gunma 371-8511, Japan.
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18
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Haas MJ, Mooradian AD. Therapeutic Interventions to Enhance Apolipoprotein A-I-Mediated Cardioprotection. Drugs 2010; 70:805-21. [DOI: 10.2165/11535410-000000000-00000] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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19
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Hashimoto K, Ishida E, Matsumoto S, Okada S, Yamada M, Satoh T, Monden T, Mori M. Carbohydrate response element binding protein gene expression is positively regulated by thyroid hormone. Endocrinology 2009; 150:3417-24. [PMID: 19324998 PMCID: PMC2703542 DOI: 10.1210/en.2009-0059] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The molecular mechanism of thyroid hormone (TH) effects to fatty acid metabolism in liver is yet to be clear. The carbohydrate response element-binding protein (ChREBP) as well as sterol response element-binding protein (SREBP)-1c plays a pivotal role in hepatic lipogenesis. Both SREBP-1c and ChREBP are target genes of liver X receptors (LXRs). Because LXRs and TH receptors (TRs) cross talk mutually in many aspects of transcription, we examined whether TRs regulate the mouse ChREBP gene expression. In the current study, we demonstrated that TH up-regulated mouse ChREBP mRNA and protein expression in liver. Run-on and luciferase assays showed that TH and TR-beta1 positively regulated the ChREBP gene transcription. The mouse ChREBP gene promoter contains two direct repeat-4 sites (LXRE1 and LXRE2) and EMSAs demonstrated that LXR-alpha and TR-beta1 prefer to bind LXRE1 and LXRE2, respectively. The direct repeat-4 deletion and LXRE2 mutants of the promoter deteriorate the positive regulation by TR-beta1, indicating that LXRE2 is functionally important for the regulation. We also showed that human ChREBP gene expression and promoter activities were up-regulated by TH. These data suggest that ChREBP mRNA expression is positively regulated by TR-beta1 and TH at the transcriptional level in mammals. This novel observation indicates that TH fine-tunes hepatic lipogenesis via regulating SREBP-1c and ChREBP gene expression reciprocally.
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Affiliation(s)
- Koshi Hashimoto
- Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, 3-39-15 Showa-machi Maebashi, Gunma, Japan.
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20
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Kim CS, Kang JG, Lee SJ, Ihm SH, Yoo HJ, Nam JS, Ahn CW, Kim KR. Relationship of low-density lipoprotein (LDL) particle size to thyroid function status in Koreans. Clin Endocrinol (Oxf) 2009; 71:130-6. [PMID: 19178521 DOI: 10.1111/j.1365-2265.2008.03436.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Dyslipidaemia is a well-known manifestation of thyroid dysfunction. Recently, small low-density lipoprotein (LDL) particle size has been linked with development of cardiovascular disease. To better understand the effects of thyroid dysfunction on the development of cardiovascular disease, we examined LDL particle size and lipid profiles in subjects with different thyroid function. METHODS Included were 46 patients with overt hypothyroidism, 57 patients with subclinical hypothyroidism, 46 patients with overt hyperthyroidism, 51 patients with subclinical hyperthyroidism, and 110 age- and sex-matched healthy control subjects. We measured LDL particle size and lipid profiles in these subjects. RESULTS No significant differences were found in LDL particle size between the groups with different thyroid function. Serum total cholesterol and LDL-cholesterol levels were significantly higher in the cases of hypothyroidism than in the cases of hyperthyroidism and the healthy control subjects. Serum triglyceride levels were higher in subjects with overt hypothyroidism than in those with overt hyperthyroidism or healthy control subjects. CONCLUSIONS LDL particle size, the emerging risk factor for atherosclerosis, did not appear to be significantly affected by the degree of thyroid dysfunction. Increased risk of atherosclerosis in hypothyroidism does not appear to be associated with LDL particle size, the non-traditional cardiovascular risk factor.
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Affiliation(s)
- Chul Sik Kim
- Department of Internal Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea.
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21
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Porta M, Ferrer-Armengou O, Pumarega J, López T, Crous-Bou M, Alguacil J, Fitó M, Jariod M, Vicente Á, Morales E, Covas MI, Puigdomènech E, Gupta N. Exocrine pancreatic cancer clinical factors were related to timing of blood extraction and influenced serum concentrations of lipids. J Clin Epidemiol 2008; 61:695-704. [DOI: 10.1016/j.jclinepi.2007.08.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Revised: 08/02/2007] [Accepted: 08/09/2007] [Indexed: 12/22/2022]
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22
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Gursoy A, Ozduman Cin M, Kamel N, Gullu S. Which thyroid-stimulating hormone level should be sought in hypothyroid patients under L-thyroxine replacement therapy? Int J Clin Pract 2006; 60:655-9. [PMID: 16805747 DOI: 10.1111/j.1368-5031.2006.00822.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We sought to determine whether relationships exist between level of thyroid-stimulating hormone (TSH) suppression and cardiovascular risk parameters such as plasma homocysteine, C-reactive protein (CRP), fibrinogen, D-dimer and serum cholesterol in patients taking L-thyroxine-replacement therapy (LT4-RT). Four hundred and two hypothyroid patients under LT4-RT were cross-sectionally evaluated. Patients were grouped according to their achieved TSH (mIU/l) levels under LT4-RT on an arbitrary manner. Those patients having a TSH value 0.4-2 were defined as group 1 (n = 154), a TSH level of 2 to less than 5.5 were defined as group 2 (n = 176) and a TSH level of 5.5 to less than 20 with a normal free T3 and free T4 level were defined as group 3 (n = 72). The three groups of patients were also compared with overt hypothyroid patients (n = 71) and healthy controls (n = 97). Homocysteine levels (micromol/l) were significantly different between the three groups (10.4 +/- 4 for group 1, 11.3 +/- 3.7 for group 2 and 13.5 +/- 4.7 for group 3; p < 0.01 for all groups). Significant differences in CRP (mg /l) levels were present between the three groups (2.6 +/- 2.6 for group 1, 3.3 +/- 2.9 for group 2 and 4.8 +/- 4.1 for group 3; p < 0.01 for all groups). Univariate analysis showed that both homocysteine and CRP levels significantly correlated with free T4 and TSH level (p < 0.01 for both groups). No statistically significant differences were noticed in respect to fibrinogen and d-dimer levels between three groups. In examining the effect of LT4-RT on lipid parameters, a tendency towards beneficial effects without achieving statistical significance was observed. Practically speaking, a target TSH level of less than 2 might be advisable to lower CRP levels and homocysteine levels, and possibly lipid parameters.
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Affiliation(s)
- A Gursoy
- Department of Endocrinology and Metabolic Diseases, Ankara University, School of Medicine, Ankara, Turkey.
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23
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Johansson L, Rudling M, Scanlan TS, Lundåsen T, Webb P, Baxter J, Angelin B, Parini P. Selective thyroid receptor modulation by GC-1 reduces serum lipids and stimulates steps of reverse cholesterol transport in euthyroid mice. Proc Natl Acad Sci U S A 2005; 102:10297-302. [PMID: 16006512 PMCID: PMC1177400 DOI: 10.1073/pnas.0504379102] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Thyroid hormones [predominantly 3,5,3'-triiodo-L-thyronine (T3)] regulate cholesterol and lipoprotein metabolism, but cardiac effects restrict their use as hypolipidemic drugs. T3 binds to thyroid hormone receptors (TRs) alpha and beta. TRbeta is the predominant isoform in liver, whereas T3 effects on heart rate are mediated mostly by TRalpha. Drugs that target TRbeta or exhibit tissue-selective uptake may improve plasma lipid levels while sparing the heart. Here, we asked how the TRbeta- and liver uptake-selective agonist GC-1 influences cholesterol and triglyceride metabolism in euthyroid mice. GC-1 treatment reduced serum cholesterol levels by 25% and serum triglycerides by 75% in chow-fed mice and also attenuated diet-induced hypercholesterolemia. GC-1 reduced plasma high-density lipoprotein cholesterol levels; increased expression of the hepatic high-density lipoprotein receptor, SR-BI; stimulated activity of cholesterol 7alpha-hydroxylase; and increased fecal excretion of bile acids. Collectively, these results suggest that GC-1 stimulates important steps in reverse cholesterol transport. Use of TRbeta and uptake selective agonists such as GC-1 should be further explored as a strategy to improve lipid metabolism in dyslipoproteinemia.
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Affiliation(s)
- Lisen Johansson
- Metabolism Unit, Center for Metabolism and Endocrinology, Department of Medicine, and Molecular Nutrition Unit, Center for Nutrition and Toxicology, NOVUM, Karolinska Institute at Karolinska University Hospital-Huddinge, SE-141 86 Stockholm, Sweden
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24
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Abstract
Subclinical and overt hypothyroidism are relatively common disorders in the general population. Thyroid hormone is known to play a role in regulating the synthesis, metabolism, and mobilization of lipids. In patients with overt hypothyroidism there is an increase in serum total cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein B, lipoprotein(a) levels, and possibly triglyceride levels. The effects of subclinical hypothyroidism on serum lipid values are less clear. The preponderance of evidence suggests that total cholesterol, LDL cholesterol, and possibly triglycerides are increased in patients with subclinical hypothyroidism, whereas high-density lipoprotein (HDL) cholesterol and Lp(a) remain unchanged. Most lipid abnormalities in patients with overt hypothyroidism will resolve with thyroid hormone replacement therapy. However, clinical trials to date have not shown a beneficial effect of thyroid hormone treatment on serum lipid levels in patients with subclinical hypothyroidism. The lipid-altering effects of thyroid hormone make it an appealing target for drug development. The development of specifically targeted thyroid hormone analogues that could potentially treat hyperlipidemia without causing systemic thyrotoxicosis is currently ongoing.
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Affiliation(s)
- Elizabeth N Pearce
- Boston University Medical Center, 88 East Newton Street, Evans 201, Boston, MA 02118, USA.
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25
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Affiliation(s)
- Jane Freeston
- Department of Rheumatology, Harrogate District Hospital, Harrogate, North Yorks, UK.
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26
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Kim JM, LaBree L, Levin L, Feldon SE. The relation of Graves' ophthalmopathy to circulating thyroid hormone status. Br J Ophthalmol 2004; 88:72-4. [PMID: 14693778 PMCID: PMC1771965 DOI: 10.1136/bjo.88.1.72] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM The risk factors and epidemiological data for Graves' ophthalmopathy with and without abnormal circulating thyroid levels were examined to determine the relation of thyroid dysfunction to ophthalmopathy. METHODS The authors retrospectively evaluated 482 patients seen with Graves' ophthalmopathy. Of these, 413 were classified as having abnormal levels of circulating thyroid hormone (ALTH) and 69 as having normal levels of circulating thyroid hormone (NLTH). RESULTS Patients in the NLTH group, compared to the ALTH group, were older on average (56 (SD 13.5) v 52 (15.4)) and had a higher age adjusted body mass index (26.1 (0.8) v 23.4 (0.3)). In addition, a higher percentage of NLTH patients had hypercholesterolaemia. Those in the ALTH group were more likely to be female (76% v 51%), to have a family history of thyroid problems, and to have had eye surgery. CONCLUSION NLTH and ALTH appear to differ from each other in terms of risk factors and epidemiological characteristics. Additionally, thyroid dysfunction seems to be associated with a more severe ophthalmopathy compared to the euthyroid state.
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Affiliation(s)
- J M Kim
- Keck School of Medicine, University of Southern California, CA, USA
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Dedecjus M, Masson D, Gautier T, de Barros JPP, Gambert P, Lewinski A, Adamczewski Z, Moulin P, Lagrost L. Low cholesteryl ester transfer protein (CETP) concentration but normal CETP activity in serum from patients with short-term hypothyroidism Lack of relationship to lipoprotein abnormalities. Clin Endocrinol (Oxf) 2003; 58:581-8. [PMID: 12699439 DOI: 10.1046/j.1365-2265.2003.01755.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Hypothyroidism is associated with a number of abnormalities in lipoprotein metabolism. Although alterations in neutral lipid exchanges among plasma lipoproteins might be one characteristic feature of hypothyroidism, a few human studies of cholesteryl ester transfer protein (CETP) activity have led to heterogeneous and fragmentary observations. The aim of the present study was to analyse the influence of short-term hypothyroidism on CETP activity, as well as on the structure and composition of lipoproteins. PATIENTS, DESIGN AND MEASUREMENTS: Sixty-six thyroidectomized patients were withdrawn from L-thyroxine (L-T4) treatment for 5 weeks. Subsequently, L-T4 therapy was reinstated for 2 months and patients were compared to 61 matched normolipidaemic controls. Serum CETP activity and mass concentration, serum lipids, apolipoproteins and lipoprotein size distribution were determined in the three groups. RESULTS Serum CETP mass concentration was significantly decreased in short-term hypothyroid patients, as compared to control subjects (3.22 +/- 0.98 vs. 3.79 +/- 1.2 mg/l, respectively; P < 0.001), and the values were normalized during L-T4 therapy. The ability of endogenous serum lipoproteins to interact with CETP was normal in short-term hypothyroid patients. Concordant observations were made regardless of whether neutral lipid transfers were measured from high-density lipoproteins (HDL) toward apo B-containing lipoproteins or from liposomes toward HDL. The size distribution of HDL was significantly different in short-term hypothyroid patients, compared to either the control or treated subgroups, with significant higher proportions of large-sized HDL2b and HDL2a (HDL2b: 13.6 +/- 6.5% before vs. 8.5 +/- 4.2% during L-T4 therapy, P < 0.05; HDL2a, 33.0 +/- 7.0% before vs. 29.3 +/- 6.9% during L-T4 therapy, P < 0.05). Although serum CETP mass concentration correlated negatively with the HDL2 to HDL3 ratio in control subjects (r = -0.588; P < 0.0001), no significant correlations were observed in hypothyroid patients, regardless of whether they were treated or not. Similarly, whereas the previously recognized positive correlation of CETP mass concentration with serum LDL cholesterol levels was found in control subjects (r = 0.264; P < 0.05), no significant correlations appeared in treated and untreated patients. CONCLUSIONS Short-term hypothyroidism may constitute an unique situation in which concomitant alterations in serum cholesteryl ester transfer protein concentration and lipoprotein parameters are disconnected.
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Affiliation(s)
- Marek Dedecjus
- Department of Thyroidology, Institute of Endocrinology, Medical University of Lódz, Lódz, Poland
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Luboshitzky R, Aviv A, Herer P, Lavie L. Risk factors for cardiovascular disease in women with subclinical hypothyroidism. Thyroid 2002; 12:421-5. [PMID: 12097204 DOI: 10.1089/105072502760043512] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Overt hypothyroidism may result in accelerated atherosclerosis and coronary heart disease (CHD) presumably because of the associated hypertension, hypercholesterolemia, and hyperhomocysteinemia. As many as 10%-15% of older women have subclinical hypothyroidism (SH) and thyroid autoimmunity. Whether SH is associated with risk for CHD is controversial. We examined 57 women with SH and 34 healthy controls. SH was defined as an elevated thyrotropin (TSH) (>4.5 mU/L) and normal free thyroxine (FT(4)) level (8.7-22.6 nmol/L). None of the patients had been previously treated with thyroxine. In all participants we determined blood pressure, body mass index (BMI), and fasting TSH, FT(4), antibodies to thyroid peroxidase and thyroglobulin, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides, folic acid, vitamin B(12), creatinine, and total plasma homocysteine levels. The SH and control groups did not differ in their total homocysteine values. Mean diastolic blood pressure was increased in SH patients versus controls (82 vs. 75 mm Hg; p < 0.01). Mean values of TC, HDL-C, LDL-C, triglycerides, TC/HDL-C, and LDL-C/HDL-C were not different in patients with SH compared with controls. Individual analysis revealed that the percentage of patients with SH having hypertension (20%), hypertriglyceridemia (26.9%), elevated TC/HDL-C (11.5%), and LDL-C/HDL-C (4%) ratios were higher than the percentages in controls. Hyperhomocysteinemia (> or = 10.98 micromol/L) was observed in 29.4% of SH and was not significantly different from the percentage in controls (21.4%). No significant correlation between TSH and biochemical parameters was detected. We conclude that subclinical hypothyroidism in middle-aged women is associated with hypertension, hypertriglyceridemia, and elevated TC/HDL-C ratio. This may increase the risk of accelerated atherosclerosis and premature coronary artery disease in some patients.
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Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 34-2000. A 71-year-old woman with an enlarging pituitary mass. N Engl J Med 2000; 343:1399-406. [PMID: 11070106 DOI: 10.1056/nejm200011093431909] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Tzotzas T, Krassas GE, Konstantinidis T, Bougoulia M. Changes in lipoprotein(a) levels in overt and subclinical hypothyroidism before and during treatment. Thyroid 2000; 10:803-8. [PMID: 11041458 DOI: 10.1089/thy.2000.10.803] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aim of this prospective, follow-up study was to examine the influence of overt hypothyroidism (OHP) and subclinical (SHP), before and during thyroxine (T4) treatment, on lipoprotein(a) [Lp(a)], other lipoproteins, and apolipoproteins. Twenty-four patients (17 females, 7 males) with OHP, aged 54 +/- 11.1 years (group A) and 23 patients (females) with SHP aged 50.1 +/- 13.2 years (group B) were evaluated and compared to 34 and 38 controls, respectively. All patients received T4 therapy in a stepwise fashion until euthyroidism was reached. Thyrotropin (TSH), free thyroxine (FT4), and total triiodothyronine (TT3) levels were measured before T4 therapy and repeatedly every 4 weeks after the initiation of treatment until the euthyroid state was reached. Levels of Lp(a), total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc), apolipoprotein A1 (apoA1) and apolipoprotein B (apoB) were measured before and 4 months after the achievement of euthyroidism. Additionally, body mass index (BMI) was also evaluated. We found that in OHP patients, levels of TC, LDLc, and apoB were elevated before treatment and decreased significantly after the return to the euthyroid state. BMI and levels of triglycerides also decreased significantly; Lp(a) was higher in OHP patients in comparison with controls and decreased significantly by 14.56% (25.29% in men and 10.34% in women) during T4 treatment. In SHP patients, levels of all common lipoproteins, apolipoproteins, and Lp(a) did not differ significantly from controls before treatment and did not change after the euthyroid stage was reached. It is concluded that in overt hypothyroidism, Lp(a) levels and most of the lipoproteins were elevated before treatment and decreased significantly. In subclinical hypothyroidism, lipoproteins and Lp(a) levels were normal at baseline and did not change during treatment.
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Affiliation(s)
- T Tzotzas
- Department of Endocrinology and Metabolism, Panagia Hospital, Thessaloniki, Greece
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Abstract
Subclinical hypothyroidism (SH) is common, especially among elderly women. There is no clear evidence to date that SH causes clinical heart disease. However, mild thyroid gland failure, evidenced solely by elevation of the serum thyrotropin (TSH) concentration, may be associated with increased morbidity, particularly for cardiovascular disease, and subtly decreased myocardial contractility. In SH, both cardiac structures and function remain normal at rest, but impaired ventricular function as well as cardiovascular and respiratory adaptation to effort may become unmasked during exercise. These changes are reversible when euthyroidism is restored. Flow-mediated vasodilatation, a marker of endothelial function, is significantly impaired in SH, and decreased heart rate variability, a marker of autonomic activity, suggests hypofunctional abnormalities in the parasympathetic nervous system. SH does result in a small increase in low-density lipoprotein (LDL) cholesterol (C) and a decrease in high-density lipoprotein (HDL)-C, changes that enhance the risk for development of atherosclerosis and coronary artery disease (CAD). After coronary revascularization, a trend toward higher rates of chest pain, dissection, and reocclusion has been noted in SH subjects. Smoking may contribute to the high incidence of SH and may aggravate its metabolic effects. Subjects with SH with marked TSH elevation and high titers of thyroid autoantibodies are at higher risk of unnoticed progression to overt hypothyroidism. Especially women over 50 years with TSH levels greater than 10 mU/L and smoking habits have the highest risk for cardiovascular complications. The magnitude of the lipid changes and the subtle impairment of left ventricular function and cardiopulmonary exercise capacity in SH may justify use of hormone replacement. Early levothyroxine (LT4) treatment in SH may reduce the C level by an average of 8% and normalize all metabolic effects in smokers, nevertheless, in some patients, LT4 therapy may exacerbate angina pectoris or an underlying cardiac arrhythmia. Longitudinal follow-up to define the actual cardiovascular disease risk associated with SH is warranted.
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Affiliation(s)
- G J Kahaly
- Department of Medicine and Endocrinology/Metabolism, Gutenberg University Hospital, Mainz, Germany.
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Lien EA, Nedrebø BG, Varhaug JE, Nygård O, Aakvaag A, Ueland PM. Plasma total homocysteine levels during short-term iatrogenic hypothyroidism. J Clin Endocrinol Metab 2000; 85:1049-53. [PMID: 10720038 DOI: 10.1210/jcem.85.3.6439] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Hypothyroidism is associated with increased cardiovascular morbidity, which cannot be fully explained by the atherogenic lipid profile observed in these patients. We have previously found elevated levels of the cardiovascular risk factor, plasma total homocysteine (tHcy), in hypothyroidism. We conducted a longitudinal study on 17 patients who had undergone total thyroidectomy for thyroid cancer. During 6 weeks of discontinued T4 substitution before radioscintigraphy (phase I), they attained a hypothyroid state, which was reversed by resupplementation (phase II). Plasma tHcy, serum creatinine, serum and red blood cell folate, serum cobalamin, and serum cholesterol were determined at 2-week intervals throughout phases I and II. There was a progressive and parallel increase in tHcy (mean, 27%), serum creatinine (37%), and serum cholesterol (100%) during phase I, and these values returned to the original level within 4-6 weeks after reinitiating T4 therapy. Serum and red blood cell folate levels showed only minor, but statistically significant, changes. In a bivariate model, serum creatinine and serum cholesterol were strongly associated with the changes observed in tHcy during short term hypothyroidism. In conclusion, we found a transient increase in both plasma tHcy and serum cholesterol during short term iatrogenic hypothyroidism, and the tHcy response is probably mainly explained by concurrent changes in renal function. The increase in both plasma tHcy and serum cholesterol may confer increased cardiovascular risk in hypothyroid patients.
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Affiliation(s)
- E A Lien
- Division of Pharmacology, University Hospital of Bergen, Norway.
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Catargi B, Parrot-Roulaud F, Cochet C, Ducassou D, Roger P, Tabarin A. Homocysteine, hypothyroidism, and effect of thyroid hormone replacement. Thyroid 1999; 9:1163-6. [PMID: 10646653 DOI: 10.1089/thy.1999.9.1163] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Elevation of total plasma concentration of homocysteine (t-Hcy) is an important and independent risk factor for cardiovascular disease. Hypothyroidism is possibly also associated with an increased risk for coronary artery disease, which may be related to atherogenic changes in lipid profile. Because hypothyroidism decreases hepatic levels of enzymes involved in the remethylation pathway of homocysteine, we prospectively evaluated fasting and postload t-Hcy in patients before and after recovery of euthyroidism. Fasting and postload t-Hcy levels were higher in 40 patients with peripheral hypothyroidism (14 with autoimmune thyroiditis and 26 treated for thyroid cancer) in comparison with those of 26 controls (13.0 +/- 7.5 vs. 8.5 +/- 2.6 micromol/L, p < .01, respectively, and 49.9 +/- 37.3 vs. 29.6 +/- 8.4 micromol/L p < .001, respectively). On univariate analysis, fasting Hcy was positively related to thyrotropin (TSH) and inversely related to folates. Multivariate analysis confirmed TSH as the strongest predictor of t-Hcy independent of age, folate, vitamin B12, and creatinine. Thyroid hormone replacement significantly decreased fasting but not postload t-Hcy. We conclude that t-Hcy is elevated in hypothyroidism. The association of hyperhomocysteinemia and lipid abnormalities occurring in hypothyroidism may represent a dynamic atherogenic state. Thyroid hormone failed to completely normalize t-Hcy. Potential benefit of treatment with folic acid in combination with thyroid hormone replacement has to be tested given that hypothyroid patients were found to have lower levels of folate.
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Affiliation(s)
- B Catargi
- Department of Endocrinology, University Hospital of Bordeaux, France.
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Tsimihodimos V, Bairaktari E, Tzallas C, Miltiadus G, Liberopoulos E, Elisaf M. The incidence of thyroid function abnormalities in patients attending an outpatient lipid clinic. Thyroid 1999; 9:365-8. [PMID: 10319942 DOI: 10.1089/thy.1999.9.365] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Thyroid disorders are known to influence lipoprotein metabolism. In the current study we examined the incidence of thyroid function abnormalities in patients attending our outpatient lipid clinic. During the last 2 years, 248 patients were admitted to our lipid clinic for the diagnosis and management of dyslipidemia. In all cases, a detailed medical history was obtained and a thorough physical examination was performed with emphasis on the presence of symptoms/signs indicative of underlying thyroid diseases. In addition to lipid parameters, thyrotropin (TSH) and free thyroxine (FT4) levels were measured in a fasting blood sample. Seven female asymptomatic patients (2.8%) had frank biochemical hypothyroidism, and 11 patients (9 female, 2 male) (4.4%) had subclinical hypothyroidism with TSH levels between 5.8-19 mU/L. After restoration of a euthyroid state with levothyroxine therapy, no significant changes in serum lipid parameters were observed in the whole group of patients with subclinical hypothyroidism. However, in 4 patients with TSH levels >12 mU/L relatively small doses of levothyroxine (75 microg/day) were followed by a significant improvement of serum lipid profile. Interestingly, 3 patients exhibited clinical or subclinical hyperthyroidism that influenced serum lipid parameters as well as the effectiveness of hypolipidemic treatment. It is concluded that thyroid function abnormalities are relatively common in dyslipidemic patients attending a lipid clinic and could significantly affect the patients' lipid profile as well as the patients' management.
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Affiliation(s)
- V Tsimihodimos
- Department of Internal Medicine, Medical School, University of Ioannina, Greece
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Martínez-Triguero ML, Hernández-Mijares A, Nguyen TT, Muñoz ML, Peña H, Morillas C, Lorente D, Lluch I, Molina E. Effect of thyroid hormone replacement on lipoprotein(a), lipids, and apolipoproteins in subjects with hypothyroidism. Mayo Clin Proc 1998; 73:837-41. [PMID: 9737219 DOI: 10.4065/73.9.837] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE To study the effect of thyroid hormone replacement on total cholesterol, low-density lipoprotein cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I and B-100, and lipoprotein(a) [Lp(a)] in subjects with hypothyroidism. MATERIAL AND METHODS In 17 patients with clinical primary hypothyroidism, studies were done before and after thyroid hormone replacement therapy. Free thyroxine and thyrotropin were determined by chemiluminescent assay. Total cholesterol and triglycerides were measured by enzymatic methods, and HDL-C was measured after dextran sulfate-MgCl2 precipitation. Apolipoprotein A-I and B-100 were assayed by immunonephelometry. For measurement of Lp(a), we used a sequential sandwich enzyme-linked immunosorbent assay. RESULTS After levothyroxine treatment, the mean concentration of thyrotropin decreased from 91.4 to 3.7 microIU/mL, and free thyroxine increased from 0.5 to 1.2 ng/ dL. Total cholesterol, triglycerides, HDL-C, low-density lipoprotein cholesterol, and apolipoprotein A-I and B-100 decreased after thyroid hormone replacement therapy. Lp(a) levels also decreased significantly (P<0.05) after treatment, from a mean of 33.4 to 25.6 mg/dL. CONCLUSION Hypothyroidism is associated with an increase in total cholesterol, triglycerides, HDL-C, apolipoprotein A-I and B-100, and Lp(a). A reduction in lipid and lipoprotein levels after thyroid hormone replacement in our study cohort resulted in a less atherogenic profile.
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Affiliation(s)
- M L Martínez-Triguero
- Endocrinology and Analysis Department, Hospital Universitario Dr. Peset, Valencia, Spain
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Tan KC, Shiu SW, Kung AW. Effect of thyroid dysfunction on high-density lipoprotein subfraction metabolism: roles of hepatic lipase and cholesteryl ester transfer protein. J Clin Endocrinol Metab 1998; 83:2921-4. [PMID: 9709970 DOI: 10.1210/jcem.83.8.4938] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
To investigate the effect of thyroid dysfunction on high-density lipoprotein (HDL) metabolism, we measured HDL subfractions, apolipoprotein A-I containing particles (LpA-I and LpA-I:A-II), and the activities of enzymes involved in the remodeling and metabolism of HDL [namely hepatic lipase (HL), lipoprotein lipase, and cholesteryl ester transfer protein (CETP)] in 18 hyperthyroid and 17 hypothyroid patients before and after treatment. HDL was subfractionated by density gradient ultracentrifugation, and LpA-I was analyzed by electroimmunodiffusion. The major changes were found in the HDL2 subfraction and in LpA-I particles. HDL2-C and LpA-I were reduced in hyperthyroidism (P < 0.01, P < 0.05, respectively) and increased in hypothyroidism (both P < 0.05) compared with their respective euthyroid matched controls. Changes in HDL2-cholesterol were reversed after treatment in both hyper- and hypothyroid patients, and LpA-I also decreased in the hypothyroid patients after treatment. HL (P < 0.05) and CETP activities (P < 0.05) were elevated in hyperthyroidism and reduced in hypothyroidism (P < 0.05, P < 0.01 respectively) and both were related to free T4 levels. The changes in HDL2-C and LpA-I correlated significantly with changes in HL after treatment but not with CETP or lipoprotein lipase. In summary, HDL metabolism was altered in thyroid dysfunction, and the effect of thyroid hormone on HDL was mediated mainly via its effect on HL activity.
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Affiliation(s)
- K C Tan
- Department of Medicine, University of Hong Kong, Hong Kong
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