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Zhang S, Li R, Ma Y, Yan Y, Ma M, Zhang K, Zhou Y, Li L, Pan L, Ying H, Xue Y. Thyroid-stimulating hormone regulates cardiac function through modulating HCN2 via targeting microRNA-1a. FASEB J 2022; 36:e22561. [PMID: 36125044 DOI: 10.1096/fj.202200574r] [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: 04/13/2022] [Revised: 08/11/2022] [Accepted: 09/09/2022] [Indexed: 11/11/2022]
Abstract
Previous studies have found microRNA-1 (miR-1) and hyperpolarization-activated cyclic nucleotide-gated channel 2 (HCN2) may be involved in the pathogenesis of thyroid hormone (TH) induced cardiac hypertrophy. However, little is known about the role of miR-1 and HCN2 in thyroid stimulation hormone (TSH)-induced cardiac dysfunction. In order to investigate the molecular mechanisms of TSH induced cardiac dysfunction and the role of miR-1/HCN2 in that process, we evaluated the expression of miR-1a/HCN2 in the ventricular myocardium of hypothyroid mice and in TSH-stimulated H9c2 cardiomyocytes. Our data revealed that hypothyroidism mice had smaller hearts, ventricular muscle atrophy, and cardiac contractile dysfunction compared with euthyroid controls. The upregulation of miR-1a and downregulation of HCN2 were found in ventricular myocardium of hypothyroid mice and TSH-stimulated H9c2 cardiomyocytes, indicating that miR-1a and HCN2 may be involved in TSH-induced cardiac dysfunction. We also found that the regulation of miR-1a and HCN2 expression and HCN2 channel activity by TSH requires TSHR, while the regulation of HCN2 expression and HCN2 channel function by TSH requires miR-1a. Thus, our data revealed the potential mechanism of TSH-induced cardiac dysfunction and might shed new light on the pathological role of miR-1a/HCN2 in hypothyroid heart disease.
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Affiliation(s)
- Shengjie Zhang
- Department of Endocrinology and Metabolism, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China.,CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ran Li
- Department of Endocrinology and Metabolism, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yiruo Ma
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ying Yan
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Mei Ma
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Keqin Zhang
- Department of Endocrinology and Metabolism, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yun Zhou
- Department of Endocrinology and Metabolism, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Ling Li
- Department of Endocrinology and Metabolism, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Lingling Pan
- Department of Endocrinology and Metabolism, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Hao Ying
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ying Xue
- Department of Endocrinology and Metabolism, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
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Grossman A, Feldhamer I, Meyerovitch J. Treatment with levothyroxin in subclinical hypothyroidism is associated with increased mortality in the elderly. Eur J Intern Med 2018; 50:65-68. [PMID: 29174213 DOI: 10.1016/j.ejim.2017.11.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/17/2017] [Accepted: 11/18/2017] [Indexed: 01/07/2023]
Abstract
INTRODUCTION It is uncertain whether subclinical hypothyroidism should be treated with levothyroxine, particularly in the elderly. This study evaluated the association between levothyroxine treatment and mortality in individuals 65years or older with subclinical hypothyroidism and TSH values <10mIU/L. METHODS A case-control study in which patients 65years or older with TSH levels of 4.2-10mIU/L who died in the years 2012-2016 ('cases') were compared with matched individuals who did not die during this period ('controls'). Matching was based on gender, age, Charlson comorbidity index, date of TSH testing, duration of follow-up and TSH quartile. All cases of known thyroid disease or cases in which anti-thyroid medications or glucocorticoids were dispensed in the year preceding the TSH evaluation were excluded. Use of levothyroxine was compared between groups. RESULTS During the follow-up period, 419 individuals died and these were matched with 1558 individuals who did not. Factors found to be associated with mortality were age, senile dementia, congestive heart failure, chronic renal failure and a history of cerebrovascular disease. On multivariate analysis, treatment with levothyroxine was associated with significantly increased mortality (HR=1.19 CI 1.03-1.38). Femoral fractures and atrial fibrillation following initiation of levothyroxine therapy were not more prevalent in individuals who died during the follow-up period. CONCLUSIONS Treatment with levothyroxine is associated with significantly increased mortality in individuals 65years or older with subclinical hypothyroidism and TSH<10.
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Affiliation(s)
- Alon Grossman
- Department of Internal Medicine E, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Israel
| | - Ilan Feldhamer
- Clalit Health Services Research and Information Department, Chief Physician Office, Israel.
| | - Joseph Meyerovitch
- Sackler Faculty of Medicine, Tel Aviv University, Israel; The Jesse Z and Sara Lea Shafer Institute for Endocrinology and Diabetes, National Center for Childhood Diabetes, Schneider Children's Medical Center of Israel and Medicine Wings, Community Division, Clalit Health Services, Tel Aviv, Israel.
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Le TN, Celi FS, Wickham EP. Thyrotropin Levels Are Associated with Cardiometabolic Risk Factors in Euthyroid Adolescents. Thyroid 2016; 26:1441-1449. [PMID: 27599541 PMCID: PMC5067795 DOI: 10.1089/thy.2016.0055] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Increased thyrotropin (TSH) levels and free triiodothyronine to free thyroxine (fT3:fT4) ratios, even within the euthyroid range, have been associated with cardiometabolic risk factors in adults but are less characterized in youth. This study sought to determine relations between TSH, thyroid hormones, and cardiometabolic risk factors in euthyroid adolescents. METHODS Data were extracted from the United States National Health and Nutrition Examination Survey, 2007-2010, for univariate and multivariate analyses of TSH, thyroid hormones, body mass index (BMI), blood pressure, lipids, and glucose metabolism. Subjects aged 12-18 years, with normal TSH and antithyroid peroxidase antibody levels, and without a history of thyroid disease, diabetes, or treatment of hypertension/dyslipidemia (n = 1167) were included. TSH and thyroid hormones were assessed for impact on BMI Z-score, systolic blood pressure (SBP) diastolic blood pressure, total cholesterol (TC), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, triglycerides, and glucose metabolism. RESULTS Univariate analyses revealed positive linear relations between TSH and SBP, TC, fasting and two-hour glucose, and homeostasis model assessment of insulin resistance (HOMA-IR). The fT3:fT4 ratio negatively correlated with high-density lipoprotein cholesterol but positively with BMI Z-score, SBP, triglycerides, fasting and two-hour glucose, fasting insulin, and HOMA-IR. In multivariate analyses controlling for age, sex, race/ethnicity, and BMI Z-score, relations between TSH and both TC and fasting glucose remained significant, and the fT3:fT4 ratio was positively associated with fasting glucose and HOMA-IR. CONCLUSIONS In an unselected population of euthyroid U.S. adolescents, TSH and thyroid hormones correlate with multiple cardiometabolic risk factors, with age- and sex-independent effects on cholesterol and glucose metabolism.
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Affiliation(s)
- Trang N. Le
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia
- Division of Pediatric Endocrinology and Metabolism, Children's Hospital of Richmond, Virginia Commonwealth University, Richmond, Virginia
| | - Francesco S. Celi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Edmond P. Wickham
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia
- Division of Pediatric Endocrinology and Metabolism, Children's Hospital of Richmond, Virginia Commonwealth University, Richmond, Virginia
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Grossman A, Weiss A, Koren-Morag N, Shimon I, Beloosesky Y, Meyerovitch J. Subclinical Thyroid Disease and Mortality in the Elderly: A Retrospective Cohort Study. Am J Med 2016; 129:423-30. [PMID: 26714213 DOI: 10.1016/j.amjmed.2015.11.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 10/31/2015] [Accepted: 11/29/2015] [Indexed: 01/07/2023]
Abstract
OBJECTIVE The association between subclinical hypothyroidism and hyperthyroidism and mortality in the elderly is poorly defined. This study was designed to evaluate the association between subclinical hypothyroidism and subclinical hyperthyroidism and mortality in the elderly and to define the thyroid-stimulating hormone values associated with excess mortality in the elderly. METHODS We performed a retrospective cohort study with a review of a computerized database of a large health care organization. Patients aged more than 65 years evaluated in the years 2002 to 2012 with documented normal free T4 values were included in the analysis. All cases of known thyroid disease or cases in which thyroid medications were dispensed were excluded. Analysis was performed only on individuals who were not treated for hyperthyroidism or hypothyroidism during the follow-up period. Subjects were divided into 3 groups based on thyroid-stimulating hormone values: normal (normal thyroid-stimulating hormone), subclinical hypothyroidism (thyroid-stimulating hormone >4.2 mIU/L), and subclinical hyperthyroidism (thyroid-stimulating hormone <0.35 mIU/L). All-cause mortality hazard ratio (HR) was compared among the 3 groups, and a subanalysis according to thyroid-stimulating hormone values was performed in those with subclinical hypothyroidism and subclinical hyperthyroidism. RESULTS A final analysis was performed on 17,440 individuals with subclinical thyroid disease (538 with subclinical hyperthyroidism [3.1%], 1956 with subclinical hypothyroidism [11.2%], 14,946 normal cases [85.7%], average age of 83 years, 10,289 were women) who were followed up for 10 years. Both subclinical hypothyroidism (HR, 1.75; confidence interval [CI], 1.63-1.88) and subclinical hyperthyroidism (HR, 2.33; CI, 2.08-2.63) were associated with significantly increased mortality, and this association persisted on multivariate analysis (subclinical hypothyroidism HR, 1.68; CI, 1.56-1.8, subclinical hyperthyroidism HR, 1.93; CI, 1.7-2.17). Crude mortality was elevated at 1, 2, and 5 years, but this association seemed to decrease as time from initial analysis increased (most significant association at 1 year). Thyroid-stimulating hormone values greater than 6.38 mIU/L were associated with the highest mortality in those with subclinical hypothyroidism after multivariate adjustment (HR, 1.708; CI, 1.38-2.12), whereas in subclinical hyperthyroidism, no threshold for increased mortality was identified. Mortality was higher. CONCLUSIONS Both subclinical hypothyroidism and subclinical hyperthyroidism are associated with increased mortality in the elderly. A threshold thyroid-stimulating hormone value (>6.35 mIU/L) exists for increased mortality in subclinical hypothyroidism, but not in subclinical hyperthyroidism.
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Affiliation(s)
- Alon Grossman
- Unit of Endocrinology and Metabolism, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Israel
| | - Avraham Weiss
- Sackler Faculty of Medicine, Tel Aviv University, Israel; Department of Geriatrics, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel
| | - Nira Koren-Morag
- Sackler Faculty of Medicine, Tel Aviv University, Israel; Department of Epidemiology and Preventive Medicine, Tel Aviv, Israel
| | - Ilan Shimon
- Unit of Endocrinology and Metabolism, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Israel
| | - Yichayaou Beloosesky
- Sackler Faculty of Medicine, Tel Aviv University, Israel; Department of Geriatrics, Rabin Medical Center, Beilinson Campus, Petah Tikva, Israel
| | - Joseph Meyerovitch
- Sackler Faculty of Medicine, Tel Aviv University, Israel; Community Division, Clalit Health Services, Tel Aviv, Israel; The Jesse Z and Sara Lea Shafer Institute for Endocrinology and Diabetes, National Center for Childhood Diabetes, Schneider Children's Medical Center of Israel, Peath Tikva, Israel.
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Vakilian F, Attaran D, Shegofte M, Lari S, Ghare S. Assessment of Thyroid Function in Idiopathic Pulmonary Hypertension. Res Cardiovasc Med 2016; 5:e29361. [PMID: 26949688 PMCID: PMC4755060 DOI: 10.5812/cardiovascmed.29361] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 08/18/2015] [Accepted: 09/04/2015] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Idiopathic pulmonary hypertension (IPAH) is a rare, debilitating, and fatal disease. Late-onset treatment can lead to right heart failure, multiple organ damage, and death. Since the thyroid plays a major role in the metabolism and hemodynamics in humans, the screening of thyroid function is crucial. Thyroid dysfunction has been reported to cause pulmonary hypertension, but the thyroid is also involved in IPAH. OBJECTIVES The aim of this study was to evaluate thyroid function in IPAH patients. PATIENTS AND METHODS Fifty-three IPAH patients aged 16 - 75 years-old were enrolled in this cross sectional study, and their right ventricular functions, hemodynamics, and six minute walk tests (SMWTs) were evaluated. Thyroid function tests were conducted, and their associations with the patients' pulmonary arterial pressures (PAPs) and functional capacities were assessed. The data were analyzed using the SPSS 15 statistical software. RESULTS In this research, 84.8% of the participants were women. The mean PAP was 51.6 mmHg (31-87) and mean thyroid stimulating hormone (TSH) level was 4.2 mIU/ml (0.7 - 10). Subclinical hypothyroidism was detected in 26 patients (49.1%). There were significant correlations of the TSH level with the right ventricular (RV) end diastolic dimension (P value = 0.05) and triiodothyronine (T3) with the tricuspid annular plane systolic excursion (TAPSE) (P value = 0.04), an inverse relationship between the SMWT and the TSH level (P value = 0.004), but no significant relationship between these parameters and the thyroxine (T4) level. CONCLUSIONS IPAH is associated with subclinical hypothyroidism and low patient functional capacity, and is more common in RV failure.
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Affiliation(s)
- Farveh Vakilian
- Preventive Atherosclerotic Research Center, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran
- Corresponding author: Farveh Vakilian, Preventive Atherosclerotic Research Center, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran. Tel: +98-9153162670, Fax: +98-5138544504, E-mail:
| | - Davod Attaran
- COPD Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran
| | - Maysam Shegofte
- Shahinfar Hospital, Mashhad Medical Branch, Islamic Azad University, Mashhad, IR Iran
| | - Shahrzad Lari
- COPD Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran
| | - Sahar Ghare
- Shahinfar Hospital, Mashhad Medical Branch, Islamic Azad University, Mashhad, IR Iran
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Tu Y, Wang Y, Ding L, Zhang J, Wu W. Development of a Novel Thyroid Function Fluctuated Animal Model for Thyroid-Associated Ophthalmopathy. PLoS One 2016; 11:e0148595. [PMID: 26872324 PMCID: PMC4752469 DOI: 10.1371/journal.pone.0148595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 01/21/2016] [Indexed: 11/18/2022] Open
Abstract
Background The establishment of a suitable and stable animal model is critical for research on thyroid-associated ophthalmopathy (TAO). In clinical practice, we found that patients treated with I-131 often exhibit TAO; therefore, we aimed to establish a novel thyroid function fluctuated animal model of TAO by simulating the clinical treatment process. Methods We treated SD rats with I-131 to damage the thyroid and then used sodium levothyroxine (L-T4) to supplement the thyroid hormone (TH) levels every seven days, leading to a fluctuating level of thyroid hormones that simulated the status of clinical TAO patients. Rats administered normal saline were considered as a control. The weight, intraocular pressure, and serum T3, T4, TSH and TRAb levels of the rats were measured, and the pathological changes were analyzed by H&E staining and transmission electron microscopy (TEM). Results The experimental rats (TAO group) exhibited significantly reduced weight and elevated intraocular pressure compared with the control rats. Meanwhile, the serum levels of T3 and T4 were up-regulated in the TAO group, but the TSH level decreased during the 10-week study. Moreover, increased numbers of blood vessels and inflammatory cell infiltrations were observed in the orbital tissues of the TAO rats, while no abnormal changes occurred in the control rats. The orbital myofibrils in the TAO rats appeared fractured and dissolved, with twisted structures. Mitochondrial swelling and vacuoles within the endoplasmic reticulum, swelling nerve fibers, shedding nerve myelin, and macrophages were found in the TAO group. Conclusion Rats treated with I-131 and sodium levothyroxine exhibited characteristics similar to those of TAO patients in the clinic, providing an effective and simple method for the establishment of a stable animal model for research on the pathogenesis and treatment of TAO.
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Affiliation(s)
- Yunhai Tu
- The Eye Hospital of Wenzhou Medical University, Wenzhou, 325000, PR China
| | - Yilong Wang
- Department of Laboratory Animal Center, Wenzhou Medical University, Wenzhou, 325000, PR China
| | - Luna Ding
- The Eye Hospital of Wenzhou Medical University, Wenzhou, 325000, PR China
| | - Jiao Zhang
- The Eye Hospital of Wenzhou Medical University, Wenzhou, 325000, PR China
| | - Wencan Wu
- The Eye Hospital of Wenzhou Medical University, Wenzhou, 325000, PR China
- * E-mail:
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Follow-up of congenital heart disease patients with subclinical hypothyroidism. Cardiol Young 2015; 25:1111-8. [PMID: 25247450 DOI: 10.1017/s1047951114001711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Subclinical hypothyroidism or mild thyroid failure is a common problem in patients without known thyroid disease. METHODS Demographic and analytical data were collected in 309, of which 181 were male and 128 were female, congenital heart disease (CHD) patients. CHD patients with thyroid-stimulating hormone above 5.5 mIU/L were also followed up from an analytical point of view to determine changes in serum glucose, cholesterol, N-terminal pro b-type natriuretic peptide, and C-reactive protein concentrations. RESULTS Of the CHD patients, 35 (11.3%) showed thyroid-stimulating hormone concentration above 5.5 mIU/L. Of them, 27 were followed up during 2.4±1.2 years - 10 were under thyroid hormone replacement treatment, and 17 were not. Of the 27 patients (25.9%), 7 with subclinical hypothyroidism had positive anti-thyroid peroxidase, and 3 of them (42.8%) with positive anti-thyroid peroxidase had Down syndrome. Down syndrome and hypoxaemic CHD patients showed higher thyroid-stimulating hormone concentrations than the rest of the congenital patients (p<0.001). No significant differences were observed in serum thyroxine, creatinine, uric acid, lipids, C-reactive protein, or N-terminal pro b-type natriuretic peptide concentrations before and after the follow-up in those CHD patients with thyroid-stimulating hormone above 5.5 mIU/L whether or not they received levothyroxine therapy. CONCLUSIONS CHD patients with subclinical hypothyroidism showed no significant changes in serum thyroxine, cholesterol, C-reactive protein, or N-terminal pro b-type natriuretic peptide concentrations whether or not they were treated with thyroid hormone replacement therapy.
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Presence of Dry Eye in Patients with Hashimoto's Thyroiditis. J Ophthalmol 2014; 2014:754923. [PMID: 25580281 PMCID: PMC4279782 DOI: 10.1155/2014/754923] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/25/2014] [Indexed: 11/17/2022] Open
Abstract
Purpose. To evaluate the tear function tests in patients with Hashimoto's thyroiditis and to compare the results with healthy subjects. Methods. A hundred and ten patients with Hashimoto's thyroiditis and 100 healthy subjects were included in this study. The presence of thyroid-associated ophthalmopathy and tear function tests were evaluated clinically. The results were first compared between the patients and the control groups and then compared between patients with NOSPECS and patients without NOSPECS. Logistic regression analyses of the risk factors for dry eye including sex, gender, free plasma thyroxine, proptosis, upper eyelid margin-reflex distance, and duration of the disease were also evaluated. Results. The mean ocular surface disease index score was significantly higher and mean Schirmer and mean tear break-up time scores were significantly lower in patients compared to control subjects. Mean Schirmer and tear break-up time scores were found to be significantly lower in patients with NOSPECS when compared to the patients without NOSPECS. Both proptosis and free plasma thyroxine levels were significantly associated with dry eye. Conclusions. Patients with Hashimoto's thyroiditis tend to develop dry eye more common than healthy subjects. Proptosis and lower free plasma thyroxine levels were found to be risk factors for the presence of dry eye.
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Brenta G, Vaisman M, Sgarbi JA, Bergoglio LM, Andrada NCD, Bravo PP, Orlandi AM, Graf H. Clinical practice guidelines for the management of hypothyroidism. ACTA ACUST UNITED AC 2014; 57:265-91. [PMID: 23828433 DOI: 10.1590/s0004-27302013000400003] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Hypothyroidism has long been known for its effects on different organ systems, leading to hypometabolism. However, subclinical hypothyroidism, its most prevalent form, has been recently related to cardiovascular risk and also to maternal-fetal complications in pregnant women. OBJECTIVES In these clinical practice guidelines, several aspects of this field have been discussed with the clear objectives of helping physicians treat patients with hypothyroidism, and of sharing some of our Latin American-based clinical experience. MATERIALS AND METHODS The Latin American Thyroid Society commissioned a Task Force on Hypothyroidism to develop evidence-based clinical guidelines on hypothyroidism. A systematic review of the available literature, focused on the primary databases of MedLine/PubMed and Lilacs/SciELO was performed. Filters to assess methodological quality were applied to select the best quality studies. The strength of recommendation on a scale from A-D was based on the Oxford Centre for Evidence--based Medicine, Levels of Evidence 2009, allowing an unbiased opinion devoid of subjective viewpoints. The areas of interest for the studies comprised diagnosis, screening, treatment and a special section for hypothyroidism in pregnancy. RESULTS Several questions based on diagnosis, screening, treatment of hypothyroidism in adult population and specifically in pregnant women were posed. Twenty six recommendations were created based on the answers to these questions. Despite the fact that evidence in some areas of hypothyroidism, such as therapy, is lacking, out of 279 references, 73% were Grade A and B, 8% Grade C and 19% Grade D. CONCLUSIONS These evidence-based clinical guidelines on hypothyroidism will provide unified criteria for management of hypothyroidism throughout Latin America. Although most of the studies referred to are from all over the world, the point of view of thyroidologists from Latin America is also given.
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Amouzegar A, Delshad H, Mehran L, Tohidi M, Khafaji F, Azizi F. Reference limit of thyrotropin (TSH) and free thyroxine (FT4) in thyroperoxidase positive and negative subjects: a population based study. J Endocrinol Invest 2013; 36:950-4. [PMID: 23873252 DOI: 10.3275/9033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Current reference values for thyroid function tests are based on data from different ethnicities and geographical areas. The aim of the present study was to determine reference intervals for thyrotropin (TSH) and free T4 (FT4), based on the criteria of the National Academy of Clinical Biochemistry (NACB) in an Iranian population. MATERIAL AND METHODS This study was conducted within the framework of Tehran Thyroid Study (TTS), an ongoing prospective cohort of 5704 randomly selected individuals, age ≥ 20 yr. A total of 2199 individuals (43.3% male, 56.7% female), based on NACB criteria were included in this study. Reference limit analysis was performed for the negative thyroid peroxidase antibody (TPOAb) group. RESULTS After applying all exclusion criteria except TPOAb positivity (10.5%), data of 2459 participants remained for analysis. Of these, 953 (43.3%) were males and 1246 (56.7%) were females; the mean ± SD age was 43.53 ± 14.16 yr. The mean ± SD and median+IQR for TSH were 1.77 mU/l ± 1.24 and 1.46 (0.93-2.23) mU/l, respectively. The 2.5th and 97.5th percentiles TSH were 0.32 mU/l and 5.06 mU/l respectively. The mean ± SD and median (IQR) for FT4 for all negative TPOAb subjects were 1.19 ± 0.16 and 1.18 (1.08-1.31) ng/dl respectively. CONCLUSION Reference ranges for thyroid function tests need to be derived from national databases. This study determined age and sex specific TSH and FT4 reference ranges in a Tehranian population, which could eventually enable clinicians to classify patients more appropriately.
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Affiliation(s)
- A Amouzegar
- Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, I.R. Iran
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Delemer B, Aubert JP, Nys P, Landron F, Bouée S. An observational study of the initial management of hypothyroidism in France: the ORCHIDÉE study. Eur J Endocrinol 2012; 167:817-23. [PMID: 23034782 PMCID: PMC3494865 DOI: 10.1530/eje-11-1041] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 10/03/2012] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To document the initial management of hypothyroidism in France with respect to diagnostic setting, investigations, and therapeutic approach. DESIGN Observational study of the management by primary care practitioners (PCPs) and endocrinologists of patients diagnosed with, and treated for, hypothyroidism during the enrollment period or the previous 6 months. METHODS A representative sample of PCPs and endocrinologists enrolled up to five consecutive patients and reported sociodemographic, clinical, therapeutic, and laboratory data. Data were submitted at baseline and at the first measurement of TSH after starting the treatment. RESULTS The analysis population comprised 1255 patients (mean (s.d.) age 52.8 (16.3) years; 84% female). Hypothyroidism was suspected on clinical grounds in 77% of patients, with goiter in 16%. Autoimmune thyroiditis, supported by positive anti-thyroid antibodies, was the most frequent diagnosis (59%), followed by iatrogenic causes (28%), of which thyroidectomy was the most common. The median baseline TSH was 8.6 mIU/l, suggesting a high incidence of subclinical hypothyroidism. Imaging studies were requested in over 75% of patients, with ultrasound performed in 98% and scintigraphy performed in 19% of these patients. Both groups of physicians treated their patients almost exclusively with levothyroxine. Endocrinologists were more likely than PCPs to provide counseling on how to take medication correctly. CONCLUSIONS This observational study of a large cohort of patients with newly diagnosed hypothyroidism in France illustrates current practice and indicates some areas where physician education may be required to optimize adherence to guidelines and cost-effectiveness.
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Affiliation(s)
- Brigitte Delemer
- Endocrinology, Hôpital Robert Debré, 45 Rue Cognacq Jay, 51100 Reims, France.
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Meyerovitch J, Antebi F, Greenberg-Dotan S, Bar-Tal O, Hochberg Z. Hyperthyrotropinaemia in untreated subjects with Down's syndrome aged 6 months to 64 years: a comparative analysis. Arch Dis Child 2012; 97:595-8. [PMID: 22535238 DOI: 10.1136/archdischild-2011-300806] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To determine whether an altered hypothalamic-pituitary-thyroid axis is inherent to Down's syndrome or if a high level of thyroid-stimulating hormone (TSH) is a feature in a subset of patients with Down's syndrome. DESIGN Comparative analysis. SETTING Major health maintenance organisation (3.8 million insured). PATIENTS A data warehouse search identified all subjects with Down's syndrome who attended Clalit Health Services in 2006 and were tested for TSH and free thyroxine (T4) level on the day of diagnosis (intention-to-treat population). The study group consisted of patients who were not diagnosed with thyroid disease or did not receive thyroid-modulating medication (n=428). Their findings were compared with a control group of healthy age- and sex-matched subjects who were randomly selected from the general population. MAIN OUTCOME MEASURES Distribution of free T4, TSH and total T3 levels. RESULTS The distribution plot for TSH showed a significant shift of the curve to higher values in the study group compared with the controls (p≤0.0001). This finding held true on further analysis of the whole intention-to-treat population (p<0.006). The free T4 distribution curve also shifted significantly to higher levels in patients with Down's syndrome (p≤0.0001). CONCLUSIONS Down's syndrome is associated with higher TSH levels. The results suggest that hyperthyrotropinaemia is an innate attribute of chromosome 21 trisomy. Therefore, T4 treatment should not be contemplated in Down's Syndrome unless the TSH is >95th centile in the presence of normal-range free T4 levels.
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Affiliation(s)
- Joseph Meyerovitch
- The Jesse Z and Sara Lea Shafer Institute for Endocrinology and Diabetes, Schneider Children's Medical Center of Israel, Petah Tikva 49202, Israel.
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13
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Abstract
Thyroid disorders are highly prevalent, occurring most frequently in aging women. Thyroid-associated symptoms are very similar to symptoms of the aging process; thus, improved methods for diagnosing overt and subclinical hypothyroidism in elderly people are crucial. Thyrotropin measurement is considered to be the main test for detecting hypothyroidism. Combined evaluations of thyroid stimulating hormone (TSH) and free-thyroxine can detect overt hypothyroidism (high TSH with low free-thyroxine levels) and subclinical hypothyroidism (high TSH with normal free-thyroxine levels). It is difficult to confirm the diagnosis of thyroid diseases based only on symptoms, but presence of symptoms could be an indicator of who should be evaluated for thyroid function. The most important reasons to treat overt hypothyroidism are to relieve symptoms and avoid progression to myxedema. Overt hypothyroidism is classically treated using L-thyroxine; elderly patients require a low initial dose that is increased every 4 to 6 weeks until normalization of TSH levels. After stabilization, TSH levels are monitored yearly. There is no doubt about the indication for treatment of overt hypothyroidism, but indications for treatment of subclinical disease are controversial. Although treatment of subclinical hypothyroidism may result in lipid profile improvement, there is no evidence that this improvement is associated with decreased cardiovascular or all-cause mortality in elderly patients. In patients with a high risk of progression from subclinical to overt disease, close monitoring of thyroid function could be the best option.
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Affiliation(s)
- Isabela M Bensenor
- Division of Internal Medicine, Hospital Universitário, University of São Paulo, São Paulo, Brazil.
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14
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Lee YK, Kim JE, Oh HJ, Park KS, Kim SK, Park SW, Kim MJ, Cho YW. Serum TSH level in healthy Koreans and the association of TSH with serum lipid concentration and metabolic syndrome. Korean J Intern Med 2011; 26:432-9. [PMID: 22205844 PMCID: PMC3245392 DOI: 10.3904/kjim.2011.26.4.432] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 06/02/2011] [Accepted: 07/01/2011] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND/AIMS The proper treatment of subclinical hypothyroidism and the normal range of serum thyroid stimulating hormone (TSH) concentration are intensely debated. However, few reports have investigated TSH concentrations in Asian ethnic groups. Therefore, the present study was designed to define the TSH reference range in a Korean population and to investigate the metabolic significance of TSH concentration. METHODS We enrolled patients who underwent medical examination at the CHA Bundang Medical Center. Anthropometric data were evaluated, and serum TSH, free T4, and lipid profiles were assayed. RESULTS A total of 7,270 subjects were included. Mean TSH concentration of the study population was 1.82 ± 0.95 mU/L, and we observed a sex-related difference in TSH concentration (male, 1.67 ± 0.87 mU/L; female, 2.02 ± 1.01 mU/L; p < 0.01). When the 2.5 and 97.5 percentiles were calculated, 95% TSH reference limits were 0.52-4.29 mU/L. TSH concentration was higher in elderly subjects, during winter, in postmenopausal women, and in obese males. Moreover, TSH showed significantly positive correlations with serum total cholesterol, triglyceride, and low density lipoprotein cholesterol regardless of sex, age, season, obesity, or menopausal status (all p < 0.01). Finally, TSH concentration was positively related to the prevalence of metabolic syndrome. CONCLUSIONS We demonstrated the association between TSH concentration within the normal reference range and serum lipid levels. TSH concentration varies according to sex, age, season, and body mass index (only in males). Moreover, high normal TSH levels were significantly associated with an increased prevalence of metabolic syndrome, which may be of importance when evaluating subjects with high normal TSH concentration.
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Affiliation(s)
- Yeo Kyung Lee
- Divison of Endocrinology and Metabolism, Department of Internal Medicine, CHA University College of Medicine, Seongnam, Korea
| | - Jo Eun Kim
- Divison of Endocrinology and Metabolism, Department of Internal Medicine, CHA University College of Medicine, Seongnam, Korea
| | - Hyun Ju Oh
- Divison of Endocrinology and Metabolism, Department of Internal Medicine, CHA University College of Medicine, Seongnam, Korea
| | - Kyung Sun Park
- Divison of Endocrinology and Metabolism, Department of Internal Medicine, CHA University College of Medicine, Seongnam, Korea
| | - Soo Kyung Kim
- Divison of Endocrinology and Metabolism, Department of Internal Medicine, CHA University College of Medicine, Seongnam, Korea
| | - Seok Won Park
- Divison of Endocrinology and Metabolism, Department of Internal Medicine, CHA University College of Medicine, Seongnam, Korea
| | - Moon Jong Kim
- Department of Family Medicine, CHA University College of Medicine, Seongnam, Korea
| | - Yong Wook Cho
- Divison of Endocrinology and Metabolism, Department of Internal Medicine, CHA University College of Medicine, Seongnam, Korea
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15
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Gupta S, Verma M, Gupta AK, Kaur A, Kaur V, Singh K. Are we using Thyroid Function Tests Appropriately? Indian J Clin Biochem 2011; 26:178-81. [PMID: 22468046 DOI: 10.1007/s12291-011-0128-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 02/14/2011] [Indexed: 11/28/2022]
Abstract
Thyroid function tests are very important for the diagnosis and monitoring of patients with thyroid dysfunction. The guidelines recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism and hyperthyroidism. The aim of this study was to analyze the ordering pattern for thyroid function tests by physicians and the analysis of results based on the clinical history. The mean age of the patients was 32.5 ± 6.5 years. Majority of samples (87.7% of total) were received from the departments of Medicine and Gynae. Thyroid profiles (47.5%) were ordered more frequently as compared to TSH only (46%). There was no significant difference in the percentage of normal reports for both types of tests. 77.8% of TFT and 76.6% of TSH samples had results within the reference range. The percentage of abnormal results was 13.7% in the patients who were screened for thyroid disorders. There is a need to redefine the case definition for thyroid dysfunction and order the appropriate test in a rational and cost effective manner.
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16
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Rotman-Pikielny P, Borodin O, Zissin R, Ness-Abramof R, Levy Y. Newly diagnosed thyrotoxicosis in hospitalized patients: clinical characteristics. QJM 2008; 101:871-4. [PMID: 18772151 DOI: 10.1093/qjmed/hcn107] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Thyrotoxicosis is often diagnosed in an outpatient setting. The most common symptoms include irritability, heat intolerance, palpitations and weakness. Sometimes, however, thyrotoxicosis is first diagnosed in the hospital setting. The prevalent symptoms in hospitalized patients with newly diagnosed thyrotoxicosis have not been fully characterized. AIM To determine the clinical characteristics of patients with thyrotoxicosis newly diagnosed during hospitalization. DESIGN A retrospective computer-based search was undertaken to detect patients that were hospitalized in our medical centre during 1999-2006, and discharged with thyrotoxicosis or thyroiditis as the primary diagnosis. RESULTS Fifty-eight patients (36F/22M; mean age 52.1 +/- 17.5 years) were identified. Weakness, weight loss and palpitations were the most common manifestations (50, 40 and 35%, respectively) and were predominantly present in patients with hyperthyroidism. Sore throat was present in 41% of patients with thyroiditis. Sinus tachycardia and atrial fibrillation occurred in 65.5 and 15.5% of the patients, more common in those with hyperthyroidism. The diagnoses on discharge were Graves' disease, subacute thyroiditis and multinodular goiter in 39.7, 34.5 and 8.9%, respectively. CONCLUSION Weakness, weight loss and palpitations were the main symptoms in patients diagnosed with thyrotoxicosis during hospitalization. Thyrotoxicosis should be included in the differential diagnosis when patients are admitted to the hospital with those symptoms.
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Affiliation(s)
- P Rotman-Pikielny
- Department of Medicine E, Meir Medical Center, Kfar-Saba Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
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17
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Fatourechi V. Upper limit of normal serum thyroid-stimulating hormone: a moving and now an aging target? J Clin Endocrinol Metab 2007; 92:4560-2. [PMID: 18056780 DOI: 10.1210/jc.2007-2285] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Papi G, Uberti ED, Betterle C, Carani C, Pearce EN, Braverman LE, Roti E. Subclinical hypothyroidism. Curr Opin Endocrinol Diabetes Obes 2007; 14:197-208. [PMID: 17940439 DOI: 10.1097/med.0b013e32803577e7] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Mild or subclinical hypothyroidism is characterized by normal serum free thyroxine concentrations with elevated serum thyroid-stimulating hormone concentrations. Subclinical hypothyroidism is relatively prevalent in the general population, especially among women and the elderly. The main cause of subclinical hypothyroidism is autoimmune chronic thyroiditis. The present report reviews the most important and recent studies on subclinical hypothyroidism, and discusses the most controversial aspects of this topic. RECENT FINDINGS Several studies have demonstrated that subclinical hypothyroidism may affect both diastolic and systolic cardiac function. It may also worsen many risk factors for cardiovascular disease, including hypertension, abnormal endothelial function, and elevated low-density lipoprotein cholesterol concentrations. Furthermore, a growing body of evidence suggests that subclinical hypothyroidism may cause symptoms or progress to symptomatic overt hypothyroidism. SUMMARY Prompt treatment of subclinical hypothyroidism in pregnant women is mandatory to decrease risks for pregnancy complications and impaired cognitive development in offspring. Children with subclinical hypothyroidism should be treated to prevent growth retardation. Whether nonpregnant adult patients with subclinical hypothyroidism should be treated, and at what thyroid-stimulating hormone values, is debatable.
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19
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Zaidi SSA, Kumar S, Gandhi SJ, Saiyed HN. Preliminary Studies on Thyroid Function in Welders. J Occup Health 2006. [DOI: 10.1539/joh.43.90] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
| | - Sunil Kumar
- Department of BiochemistryNational Institute of Occupational HealthAhmedabadIndia
| | - Sumitra J. Gandhi
- Department of BiochemistryNational Institute of Occupational HealthAhmedabadIndia
| | - Habibullah N. Saiyed
- Department of BiochemistryNational Institute of Occupational HealthAhmedabadIndia
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20
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Wu AHB. A selected history and future of immunoassay development and applications in clinical chemistry. Clin Chim Acta 2006; 369:119-24. [PMID: 16701599 DOI: 10.1016/j.cca.2006.02.045] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Accepted: 02/27/2006] [Indexed: 02/07/2023]
Abstract
BACKGROUND The first immunoassay was described by Berson and Yalow in 1959. Their work resulted in their receipt of the Nobel Prize in Medicine in 1977. Since this introduction, immunoassays have evolved considerably. METHODS There have been several milestones that have led to the proliferation of modern immunoassays. The development of monoclonal antibodies from mouse hydridoma cells by Millstein and Kohler (Nobel Prize in 1984) enabled the production of high quantities of antibodies with well characterized epitope specificity. The first homogenous immunoassay (no separation step required) was the Enzyme Multiplied Immunoassay Technique (EMIT), which enabled adaptation of this assay onto automated chemistry platforms. EMIT was also one of the first immunoassay that made use of non-isotopic labels. Other non-isotopic labels became available such as chemiluminescence to improve the analytical sensitivity of immunoassays. The advantages of high-sensitivity immunoassays have created expanded diagnostic roles for some existing assays such as thyroid stimulating hormone for hyperthyroidism, C-reactive protein for cardiovascular risk assessment, and other applications. The development of instrumentation capable of automated heterogeneous immunoassays (separation step to improve sensitivity) has enabled movement of this technology from the "special chemistry" sections of a clinical laboratory into the "core" laboratory with other high-volume testing. CONCLUSION Today, immunoassays play a prominent role in the analysis of many clinical laboratory analytes such as proteins, hormones, drugs, and nucleic acids. The future involves development of assays with higher sensitivities which will enable the discovery of new biomarkers for disease diagnosis, and technology that will enable simultaneous multimarker analysis of tests whose needs are naturally grouped together (e.g., cytokines and allergens).
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Affiliation(s)
- Alan H B Wu
- Department of Laboratory Medicine, University of California, San Francisco, Clinical Chemistry Laboratory, San Francisco General Hospital, San Francisco, CA 94110, USA.
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21
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Doux JD, Yun AJ. When normal is not: The dilemma of interpreting laboratory averages of bioactive molecules subject to heterogeneous regulatory feedback and epigenetic mosaicism. Med Hypotheses 2006; 66:1216-21. [PMID: 16406353 DOI: 10.1016/j.mehy.2005.11.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Accepted: 11/14/2005] [Indexed: 01/30/2023]
Abstract
Complex regulatory systems control the levels of many bioactive molecules in the serum. These systems involve the integration of feedback responses from numerous tissues. End-organs and tissues can manifest epigenetic mosaicism, particularly with aging or disease states. We propose that an isolated lab value may reflect a blended average of inhomogeneous feedback responses from target tissues in various states of dysfunction. Reliance on such data may underestimate the state of systemic dysfunction. Yet in clinical practice, normal serum levels of a given molecule and its associated regulatory machinery are often assumed to reflect normal body homeostasis and tissue function. Organism-wide integration of abnormally high and low levels of bioactivity of a molecule in different tissues may yield apparently normal serum values of the bioactive molecule and known components of its regulatory system. We specifically discuss thyroid hormone regulation and function as a case example. Epigenetic reprogramming of either regulatory loops or tissue responses represents another way in which normal serum levels of the molecule may obscure target-organ dysfunction. The proposed idea has broad implications for disease pathogenesis, diagnosis, and therapies. A model where individual tissues employ illegitimate signaling to subvert the concerns of the organism as a whole is also proposed.
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Affiliation(s)
- John D Doux
- Palo Alto Institute, Palo Alto, CA 94301, USA.
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22
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Abstract
The term 'subclinical hypothyroidism' applies to patients who have mildly increased levels of serum thyrotropin hormone (TSH) and normal levels of thyroxine and liothyronine (triiodiothyronine). This very common condition, also called 'mild thyroid failure', accounts for 75% of patients who have increased serum TSH. For patients with sustained increases above 10 mIU/L, there is uniform agreement that thyroxine therapy is indicated. Therapy for milder forms of hypothyroidism is controversial. Some randomized clinical trials favor therapy for mild thyroid failure, but they are inconclusive because they lack stratification for the subgroup of patients with TSH levels below 10 mIU/L. For this subgroup, we recommend individualized management. The presence of goiter, positive thyroperoxidase (TPO) antibodies, manic-depressive disorder, fertility problems, or pregnancy or the anticipation of pregnancy favors the initiation of therapy. Positive TPO antibodies are a strong indication for therapy because of the high likelihood in these patients of progression to overt hypothyroidism; patients who are already receiving thyroxine should have adjustments of their dosage. Children and adolescents with mild thyroid failure should also be treated because of possible adverse effects on growth and development. It has been suggested that subclinical hypothyroidism is a cardiovascular risk factor, however further investigation is needed. The controversy surrounding therapy will not be resolved until more randomized studies are available for the subgroup of patients with TSH <10 mIU/L, and until the question of cardiovascular risk factors is further clarified.
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Affiliation(s)
- Vahab Fatourechi
- Division of Endocrinology, Metabolism, Diabetes, Nutrition, and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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Mahjoubi-Samet A, Hamadi F, Soussia L, Fadhel G, Zeghal N. Dimethoate effects on thyroid function in suckling rats. ANNALES D'ENDOCRINOLOGIE 2005; 66:96-104. [PMID: 15959409 DOI: 10.1016/s0003-4266(05)81705-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aim of our work is to study dimethoate effects on thyroid function given in drinking water (40 mg/kg body weight, equivalent to 0.2 g/L) to mothers from day zero until the 10th day after delivery. Pups and their mothers were sacrificed on day ten after parturition. Compared to a control group, dimethoate-treated pups showed a 48% decrease in body weight which could be attributed to a defect in thyroid hormones. Indeed, after treatment by dimethoate, plasma rates of free T4 and T3 decreased by 56% and 40% in the young and by 27% and 15% in dams respectively. We can attribute the reduction in plasma thyroxine and triiodothyronine rates to a decrease in thyroid iodine levels (-75%) in the young and (-24%) in their mothers. The decrease in production of thyroid hormones after dimethoate treatment affect thyroid stimulating hormone (TSH) levels. In fact, plasma TSH levels were multiplied in dimethoate-treated group by factors of 2.31 in dams and 1.96 in their offspring. These biochemical modifications confirmed the histological thyroid aspects of pups and dams. In fact, in dimethoate-treated rats, some thyroid follicles of pups presented vesicular cavities without colloid; others contained colloid. However in dams, thyroid follicles presented cubical epithelial cells which surrounded empty vesicular cavities.
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Affiliation(s)
- A Mahjoubi-Samet
- Animal Physiology Laboratory, Life Sciences department, Sciences Faculty of Sfax, Route de la Soukra Km 3.5. BP 802. 3018 Sfax-Tunisie
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Andersen S, Bruun NH, Pedersen KM, Laurberg P. Biologic variation is important for interpretation of thyroid function tests. Thyroid 2003; 13:1069-78. [PMID: 14651790 DOI: 10.1089/105072503770867237] [Citation(s) in RCA: 148] [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
Large variations exist in thyrotropin (TSH) and thyroid hormones in serum. The components of variation include preanalytical, analytical, and biologic variation. This is divided into between- and within-individual variation. The latter consists of circadian and seasonal differences although there are indicators of a genetically determined starting point. The ratio of within- to between-individual variation describes the reliability of population-based reference ranges. This ratio is low for serum TSH, thyroxine (T(4)) and triiodothyronine (T(3)) indicating that laboratory reference ranges are relatively insensitive to aberrations from normality in the individual. Solutions are considered but reducing the analytical variation below the calculated analytical goals of 7%, 5% and 12% for serum T(3), T(4), and TSH does not improve diagnostic performance. Neither does determination of the individual set-point and reference range. In practice this means that population-based reference ranges are necessary but that it is important to recognize their limitations for use in individuals. Serum TSH responds with amplification to minor alterations in T(4) and T(3). A consistently abnormal TSH probably indicates that T(4) and T(3) are not normal for the individual even when inside the laboratory reference range. This underlines the importance of TSH in diagnosis and monitoring of thyroid dysfunctions. Also, it implies that subclinical thyroid disease may be defined in purely biochemical terms. Under critical circumstances such as pregnancy where normal thyroid function is of importance for fetal brain development, subclinical thyroid disease should be treated. Even TSH within the reference range may be associated with slightly abnormal thyroid function of the individual. The clinical importance of such small abnormalities in thyroid function in small children and pregnant women for brain development remains to be elucidated.
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Affiliation(s)
- Stig Andersen
- Department of Endocrinology and Medicine, University Hospital Aalborg, Aalborg, Denmark.
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Fatourechi V. Mild thyroid failure [subclinical hypothyroidism]: to treat or not to treat? COMPREHENSIVE THERAPY 2002; 28:134-9. [PMID: 12085461 DOI: 10.1007/s12019-002-0051-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Most endocrinologists agree that if the serum TSH level is above 10 mIU/L, thyroxine therapy is indicated. For lower values of serum TSH, thyroxine therapy depends on the presence or absence of antithyroid antibodies and the associated clinical condition.
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Affiliation(s)
- Vahab Fatourechi
- Division of Endocrinology, Metabolism Nutrition and Internal Medicine, Mayo Clinic, Rochester, Minn., USA
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26
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Abstract
Advances in thyroid disorder diagnosis have created new thyroid disorder categories such as subclinical hyperthyroidism and subclinical hypothyroidism. In the 1980s, immunometric assaying for thyroid stimulating hormone (TSH) emerged and became defined as the most cost-effective test in thyroid disorder screening. The second step in the screening of thyroid disorders is to determine free thyroxine (FT4), and cost-effective methods for its detection are now available. Using TSH and FT4, it is possible to determine four situations: clinical hyperthyroidism, clinical hypothyroidism, subclinical hyperthyroidism and subclinical hypothyroidism. Subclinical hypothyroidism can be a strong indicator of risk for atherosclerosis and myocardial infarction in elderly women. Cardiovascular mortality among Brazilian women is one of the highest in the Western world. The best-known risk factors for cardiovascular diseases are high blood pressure, smoking, diabetes, and hypercholesterolemia. Although these are recognized as primary risk factors, there are other risk factors that could be identified as primordial risk factors. This may be the case for subclinical hypothyroidism. Early detection of thyroid disorders in women over fifty could be a highly cost-effective option in the prevention of cardiovascular disorders among Brazilian women.
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Affiliation(s)
- Isabela Bensenor
- Departamento de Clínica Médica, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, Brazil.
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27
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Burke MD. Selected endocrine test strategies. Clin Lab Med 2002; 22:421-34. [PMID: 12134469 DOI: 10.1016/s0272-2712(01)00014-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The diagnosis of endocrine disorders lends itself to sequential test strategy. The strategies outlined in this article deal with problems that are either commonly encountered in clinical practice, reflect recently acquired knowledge, or both. Wherever possible a clearly defined algorithmic approach is used. The purpose is to emphasize the most appropriate general approach to test strategy.
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Affiliation(s)
- M Desmond Burke
- Department of Pathology, Division of Laboratory Medicine, Weill Medical College, Cornell University, 525 East 68th Street, New York, NY 10021, USA. dburke2mail.med.cornell.edu
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Abstract
The term subclinical thyroid disease is used to describe asymptomatic thyroid abnormalities found on imaging studies or laboratory tests. Thyroid nodules not palpable on physical examination but detected on imaging studies performed for other purposes are called incidentalomas. In the absence of risk factors for thyroid cancer, nodules that are less than 1 cm in diameter do not require biopsy. Subclinical hyperthyroidism is defined as suppressed serum sensitive thyrotropin (TSH) and normal serum thyroxine and triiodothyronine levels. This condition may adversely affect the heart and the bones and should be treated, especially in patients older than 60 years. Subclinical hypothyroidism, defined as mildly elevated serum TSH and normal serum thyroxine levels, is the most common thyroid dysfunction. In patients with subclinical hypothyroidism, thyroxine therapy should be given if the serum TSH level is higher than 10 mIU/L. For TSH values between 5 and 10 mIU/L, the decision for therapy should be individualized and depends on the level of TSH, presence of antithyroid antibodies, and clinical factors.
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Affiliation(s)
- V Fatourechi
- Division of Endocrinology, Metabolism, Nutrition and Internal Medicine, Mayo Clinic, Rochester, Minn 55905, USA
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Zaidi SS, Bhatnagar VK, Gandhi SJ, Shah MP, Kulkarni PK, Saiyed HN. Assessment of thyroid function in pesticide formulators. Hum Exp Toxicol 2000; 19:497-501. [PMID: 11204551 DOI: 10.1191/096032700677928536] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Thirty male pesticide formulators exposed to the dust and liquid formulation of endosulfan, quinalphos, chlorpyriphos, monocrotophos, lindane, parathion, phorate, and fenvalerate and 20 comparable control subjects from the same area of study were examined for the evaluation of thyroid function tests. The level of TSH was elevated (about 28%) in pesticide formulators as compared to a control group, but the increase was statistically insignificant. Based on the individual TSH measurement, 3 of 30 formulators had isolated elevated levels of TSH and seem to have acquired sub-clinical hypothyroidism; five had TSH values slightly elevated to the upper boarder line (4.03 muIU/ml); and the majority of formulators (N= 22) had TSH values in the normal range varying from 1.29 to 3.9 muIU/ml. Total T3 was suppressed significantly (P< 0.01) in formulators, while marginal decrease (about 7%) was noticed in T4 level. This study indicated thyroid function impairment in few pesticide formulators.
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Affiliation(s)
- S S Zaidi
- National Institute of Occupational Health (Indian Council of Medical Research), Meghani Nagar, Ahmedabad
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Larson J, Anderson EH, Koslawy M. Thyroid disease: a review for primary care. JOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS 2000; 12:226-32. [PMID: 11930445 DOI: 10.1111/j.1745-7599.2000.tb00186.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Manifestations of thyroid disease include hyperthyroidism and hypothyroidism. In the past, the diagnosis of thyroid disease has been perplexing due to the multisystemic effects of thyroid hormone and the lack of specificity in laboratory tests. New methods of measuring thyroid function have made screening and diagnosis of thyroid dysfunction both more accurate and cost-effective. Testing for thyroid stimulating hormone (TSH) is now a first-line diagnostic procedure and, in some cases, may be the only test indicated. The general pathophysiology of thyroid, the diagnosis and management of thyroid disease, and current screening recommendations are reviewed here.
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Affiliation(s)
- J Larson
- School of Nursing, University of Connecticut, 231 Glenbrook Rd. U2026, Storrs, CT 06269-2026, USA
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Klee GG. Maximizing Efficacy of Endocrine Tests: Importance of Decision-focused Testing Strategies and Appropriate Patient Preparation. Clin Chem 1999. [DOI: 10.1093/clinchem/45.8.1323] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
The efficacy of endocrine tests depends on the choice of tests, the preparation of the patients, the integrity of the specimens, the quality of the measurements, and the validity of the reference data. Close dialogue among the clinicians, the laboratory, and the patients is a key factor for optimal patient care. The characteristics of urine and plasma samples and the advantages and limitations of paired test measurements are presented. The importance of test sequence strategies, provocative or inhibitory procedures, and elimination of drug interferences is illustrated with four cases involving Cushing syndrome, pheochromocytoma, primary aldosteronism, and hypercalcemia. For each of these scenarios, key clinical issues are highlighted, along with discussions of the best test strategies, including which medications are likely to interfere. The importance of targeting laboratory tests to answer well-focused clinical decisions is emphasized. The roles of some time-honored provocative procedures are questioned in light of more sensitive and specific analytic methods. The importance of decision-focused analytical tolerance limits is emphasized by demonstrating the impact of analytic bias on downstream medical resource utilization. User-friendly support systems to facilitate the implementation of test strategies and postanalytic tracking of patient outcomes are presented as essential requirements for quality medical practice.
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Affiliation(s)
- George G Klee
- Department of Laboratory Medicine and Pathology, Mayo Clinic and Mayo Foundation, 200 First Street S.W., Rochester, MN 55905. Fax 507-284-4542; e-mail
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Beyer IW, Karmali R, Demeester-Mirkine N, Cogan E, Fuss MJ. Serum creatine kinase levels in overt and subclinical hypothyroidism. Thyroid 1998; 8:1029-31. [PMID: 9848718 DOI: 10.1089/thy.1998.8.1029] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Overt hypothyroidism is known to be associated with increased serum creatine kinase (CK) levels. However, there is little information on CK levels in subclinical hypothyroidism. The aim of the study was to assess the relationship between CK levels and thyroid function in overt and subclinical hypothyroidism. Thyroid function tests (thyrotropin [TSH], free thyroxine [FT4], free triiodothyronine [FT3]) and the serum levels of CK were obtained from 23 patients admitted to a general hospital for illnesses other than thyroid or muscular diseases, myocardial ischemia, or brain damage. Overt hypothyroidism, based on thyroid function tests, was present in 10 patients, whereas hypothyroidism could be classified as subclinical in the other 13. A positive correlation was observed between CK and thyrotropin, and to a lesser extent between CK and thyroid hormones. Moreover, the correlation between CK and TSH and between CK and FT4 was detectable in subclinical hypothyroidism. Our data suggest that even in subclinical hypothyroidism there is some degree of dysfunction in skeletal muscle metabolism.
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Affiliation(s)
- I W Beyer
- Université Libre de Bruxelles, Department of Internal Medicine, Hôpital Universitaire Brugmann, Brussels, Belgium
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