Mecanismos fisiopatológicos del hipotiroidismo en la infertilidad femenina / Physiopathological mechanisms of hypothyroidism on feminine infertility

INTRODUCCIÓN Y OBJETIVO: El hipotiroidismo es una condición frecuente en mujeres en Chile. Existe evidencia contundente de una fuerte asociación entre esta patología e infertilidad femenina. El objetivo de esta revisión es resumir los principales mecanismos fisiopatológicos descritos en la literatura que explicarían la infertilidad femenina en mujeres hipotiroideas. MÉTODOS: Se llevó a cabo una búsqueda bibliográfica por medio PubMed con los términos: hipotiroidismo, infertilidad y fisiopatología. De todos los artículos se seleccionaron únicamente los correspondientes a población femenina. Incluimos tanto hipotiroidismo clínico como subclínico, y mujeres eutiroideas con anti-TPO (+). RESULTADOS: Clasificamos la literatura disponible en tres grupos de mecanismo fisiopatológicos. En primer lugar, la deficiencia de hormonas tiroideas T3 y T4 producirían alteraciones en la foliculogénesis, ovulación, implantación y placentación. En segundo lugar, la hiperprolactinemia secundaria al hipotiroidismo llevaría a un hipogonadismo hipogonadotrópico e insuficiencia en la fase lútea. En tercer lugar, los anticuerpos anti-TPO, independientemente de los niveles de hormonas tiroideas, podrían tener una reacción cruzada con proteínas presentes en el útero, afectando el proceso de implantación. CONCLUSIONES: El hipotiroidismo produce infertilidad femenina por variados mecanismos fisiopatológicos. Dada la variabilidad de estos, existe un mayor espectro de aproximaciones terapéuticas para tratar mujeres hipotiroideas con problemas de fertilidad.

INTRODUCTION AND OBJECTIVE: Hypothyroidism is a frequent condition in Chile in women in Chile. There is strong evidence of an association between this pathology and feminine infertility. The objective of this review is to summarize the main physiopathological mechanisms described in the literature that explain infertility in women with hypothyroidism. METHODS: We performed a bibliographic search on PubMed with the terms: hypothyroidism, infertility, physiopathology. Among all the articles we selected only the ones regarding to feminine population. We included both clinical and subclinical hypothyroidism, and euthyroid women with Anti-TPO (+). RESULTS: We classified the available literature into three groups of physiological mechanisms. In the first place, decreased thyroid hormones T3 and T4 may lead to alterations on folliculogenesis, ovulation, implantation and placentation. Secondly, hyperprolactinemia secondary to hypothyroidism would produce hypogonadotropic hypogonadism and luteal phase insufficiency. Thirdly, anti-TPO antibodies, independently on thyroid hormones levels, may have a cross reactivity towards proteins in the womb, negatively affecting the process of implantation. CONCLUSIONS: Hypothyroidism produces infertility through varied physiopathological mechanisms. Due to their variability, there is a wider scope for therapeutical approaches to treat women with hypothyroidism and fertility problems.

Relación entre hipotiroidismo y síndrome de ovario poliquístico / The relationship between hypothyroidism and polycystic ovary syndrome

INTRODUCCIÓN: Se ha documentado la asociación del síndrome de ovario poliquístico con alteraciones metabólicas y enfermedades cardiovasculares. Su relación con trastornos autoinmunitarios no está claramente establecida, pero se ha encontrado una importante prevalencia de desórdenes tiroideos en pacientes con síndrome de ovario poliquístico. OBJETIVO: Describir las diferentes teorías existentes que puedan explicar la relación entre hipotiroidismo y síndrome de ovario poliquístico, junto con su posible impacto en la morbilidad asociada. Método: Se realizó una búsqueda en PubMed y LILACS con las palabras clave "Polycystic ovary síndrome", "Hypotyroidism", "thyroid disease" y sus respectivos términos en español, durante julio de 2020. Resultados: Se seleccionaron 51 artículos relacionados con el tema, publicados en los últimos 10 años. La fisiopatogenia entre ambos trastornos no está claramente establecida. Se ha encontrado un importante impacto metabólico en este grupo de pacientes y se considera que su riesgo cardiovascular podría estar aumentado. CONCLUSIONES: Al considerarse la prevalencia significativa y las complicaciones que tanto a corto como a largo plazo podrían tener las mujeres con ambas alteraciones, se hace necesario discutir la necesidad de la exclusión del hipotiroidismo de los criterios diagnósticos aplicados para el síndrome, la tamización temprana y el estudio de las implicaciones terapéuticas que trae su abordaje.

INTRODUCTION: The association of polycystic ovary syndrome with other metabolic disorders and cardiovascular diseases has been documented; nevertheless, its relationship with autoimmune disorders is not clearly established, however, an important prevalence of thyroid disorders has been found in this group of patients. OBJECTIVE: To describe the different existing theories that can explain the relationship between hypothyroidism and polycystic ovary syndrome along with its possible impact on associated morbidities. Method: A search was conducted in PubMed and LILACS with the keywords of "Polycystic ovary syndrome", "Hypothyroidism", "Thyroid disease" and with its respective Spanish terms, in July 2020. Results: 51 articles related to the subject were selected, published in the last 10 years. The pathogenesis between both disorders is not clearly established. An important impact has been found at the metabolic level in this group of patients and it is considered that their cardiovascular risk could be increased. CONCLUSIONS: Considering the significant prevalence and complications that both short and long term, women with both alterations could have, it is necessary to discuss the need for the exclusion of hypothyroidism from the diagnostic criteria applied for the syndrome, early screening of the syndrome, and the study of the therapeutic implications that its approach brings.

Thyroid gland changes in patients with acromegaly

ABSTRACT Objective Acromegaly is characterized by high neoplastic morbidity as a side effect of growth hormone (GH) hypersecretion. Increased incidence of goiter, thyroid carcinoma, and thyroid dysfunction is also reported. The aim of the present study was to find the prevalence of thyroid dysfunction and goiter in patients with acromegaly and determine its relationship to disease activity, disease duration, and the presence of secondary hypothyroidism. Subjects and methods In a cross-sectional study of the period 2008-2012 were included 146 patients with acromegaly (56 men, 90 women) of mean age 50.3 ± 12.4 years. Acromegaly disease activity and thyroid function were evaluated in all patients. Thyroid ultrasonography was performed to calculate thyroid volume and detect the presence of nodular goiter. Results Ninety-one patients were determined to have an active disease, and 55, a controlled disease. The mean thyroid volume in patients without previous thyroid surgery was 37.6 ± 38.8 mL. According to disease activity, thyroid volume was significantly higher in patients with active disease (38.5 ± 45.4 mL vs. 27.2 ± 18.4 mL, p = 0.036). A weak positive correlation was found between thyroid volume and insulin-like growth factor 1 (IGF-1) in the whole group and in females (R = 0.218; p = 0.013, and R = 0.238; p = 0.037, respectively). There was no significant correlation of thyroid volume with disease duration and GH level in the whole group and in both sexes. The patients with secondary hypothyroidism had twofold smaller thyroid volume, relative to the rest of the group. The prevalence of thyroid dysfunction was 39%, with a female to male percentage ratio of 1.73. Goiter was diagnosed in 87% of patients, including diffuse goiter (17.1%) and nodular (69.9%), with no significant difference between patients with active and controlled disease or the presence of secondary hypothyroidism. Conclusions Thyroid volume in patients with acromegaly depends on disease activity and the presence of secondary hypothyroidism as a complication. The increased prevalence of nodular goiter determines the need of regular ultrasound thyroid evaluation in the follow-up of patients with acromegaly. Arch Endocrinol Metab. 2020;64(3):269-75

Efectos del entrenamiento físico en pacientes con hipotiroidismo subclínico: una revisión sistemática / Effects of physical training in patients with subclinical hypothyroidism: a systematic review

OBJETIVO: revisar la bibliografía disponible sobre los efectos del entrenamiento en pacientes con hipotiroidismo subclínico. MATERIAL Y MÉTODOS: se realizó una revisión de las bases de datos PubMed, Scopus y Springer incluyendo artículos originales publicados desde el 01 enero del 2009 hasta 11 de junio de 2019 en los que se intervino de forma aguda o prolongada con entrenamiento en pacientes con hipotiroidismo subclínico. Los conectores utilizados fueron AND y OR junto con las palabras claves hypothyroidism, exercise, effect, thyroid hormone, training, subclinical hypothyroidism, underactive thyroid, aerobic training, anaerobic training, resistance training, strength training. Las palabras claves debían encontrarse en los títulos y resumen. Se evaluó en dos fases la elegibilidad de los artículos según: título, idioma, año de publicación y el análisis de texto completo. RESULTADOS: 8 de las 17 publicaciones encontradas en la búsqueda cumplieron con los criterios de inclusión. En estos se reportó una mejora en la calidad de vida y capacidad física posterior a la aplicación de un programa de entrenamiento mientras que ante un ejercicio físico agudo se observó una cinética cardiorrespiratoria más lenta en pacientes con HSC. CONCLUSIONES: el entrenamiento físico produce mejoras en la calidad de vida y capacidad aeróbica. Se requiere de más investigación en el área.

OBJECTIVE: the aim of this article was to perform a systematic review investigating the effects of training in patients with subclinical hypothyroidism (HSC). MATERIAL AND METHODS: PubMed, Scopus and Springer databases were searched. Original articles published between January 01, 2009 -June 11, 2019 in which acute exercise or prolonged training programs applied to patients with HSC were included. The search was made using AND & OR boolean operators and the following key words: hypothyroidism, exercise, effect, thyroid hormone, training, subclinical hypothyroidism, underactive thyroid, aerobic training, anaerobic training, resistance training, strength training, were required to be found in titles or abstract for the first eligibility phase, while the second phase consisted in article analysis. RESULTS: eight studies met the inclusion criteria. Improves in quality of life, and physical fitness were found as effect of a training program while kinematic cardiorespiratory acute response to exercise was found to be slower in patients with HSC. CONCLUSIONS: physical training improves quality of life and aerobic capacity in patients with subclinical hypothyroidism. More investigation in this area is needed.

Subclinical Thyroid Dysfunction was not Associated with Cardiac Arrhythmias in a Cross-Sectional Analysis of the ELSA-Brasil Study / Disfunção Tireoidiana Subclínica não foi Associada com Arritmias Cardíacas em Análise Transversal do Estudo ELSA-Brasil

Abstract Background: The association of subclinical thyroid dysfunction (STD) with cardiac arrhythmias remains controversial, particularly in the non-elderly population. Objective: To investigate whether STD was associated with cardiac arrhythmias in a cohort of middle-aged and older adults. Methods: Baseline data of the Longitudinal Study of Adult Health, ELSA-Brasil (35-74 years) were collected from 2008 to 2010. After exclusion of clinical hypothyroidism and hyperthyroidism, participants were categorized as euthyroidism (TSH = 0.4-4.0 µU/mL), subclinical hypothyroidism (TSH > 4.0 µU/mL; FT4 = 0.8-1.9 ng/dL), and subclinical hyperthyroidism (TSH < 0.4 µU/mL; FT4 = 0.8-1.9 ng/dL). The prevalence rates of tachycardia (HR > 100) and bradycardia (HR < 60), atrial fibrillation/flutter, conduction disorders, extrasystoles, low QRS voltage, prolonged QT intervals, and persistent supraventricular rhythms were compared between groups after adjusting for age, sex, comorbidities, lifestyle, body mass index and medications. Results: The HR data of 13,341 participants (52% female; median age, 51 years) and the electrocardiogram readings of 11,795 were analyzed; 698 participants (5.23%) were classified as subclinical hypothyroidism, 193 (1.45%) as subclinical hyperthyroidism, and 12,450 (93.32%) as euthyroidism. The prevalence of rhythm and conduction disorders was similar, as were HR medians, even in the subgroups with TSH < 0.01 UI/mL or > 10.0 UI/mL or in older adults. Conduction disorders were less prevalent in older adults with subclinical hypothyroidism (adjusted OR = 0.44; 95% CI 0.24 to 0.80). Conclusion: In this large, multicenter and cross-sectional study, STD was not associated with cardiac arrhythmias, but a longitudinal assessment is necessary.

Resumo Fundamento: A associação de disfunção tireoidiana subclínica (DST) com arritmias cardíacas permanece controversa, particularmente na população não idosa. Objetivo: Investigar se a DST está associada a arritmias cardíacas em uma coorte de adultos de meia-idade e idosos. Métodos: Dados da linha de base do Estudo Longitudinal de Saúde do Adulto, ELSA-Brasil (35-74 anos) foram coletados de 2008 a 2010. Após exclusão de hipo e hipertireoidismo clínicos, os participantes foram categorizados como eutireoidismo (TSH = 0,4 a 4,0 µU/mL), hipotireoidismo subclínico (TSH > 4,0 µU/mL; T4L = 0,8-1,9 ng/dL) e hipertireoidismo subclínico (TSH <0,4 µU/mL; T4L = 0,8 a 1,9 ng/dL). As prevalências de taquicardia (Frequência cardíaca [FC] > 100) e bradicardia (FC < 60), fibrilação atrial/flutter, distúrbios de condução, extrassístoles, baixa voltagem do QRS, intervalos QT prolongados e ritmo supraventricular persistente foram comparadas entre os grupos após ajuste por idade, sexo, comorbidades, estilo de vida, índice de massa corporal e uso de medicamentos. Resultados: Foram analisados os dados da FC de 13.341 participantes (52% do sexo feminino; idade média de 51 anos) e das leituras de 11.795 ECG; 698 participantes (5,23%) foram classificados como hipotireoidismo subclínico, 193 (1,45%) como hipertireoidismo subclínico e 12.450 (93,32%) como eutireoidismo. A prevalência de distúrbios de ritmo e condução foi semelhante, assim como as médias de FC, mesmo nos subgrupos com TSH < 0,01 UI/mL ou > 10,0 UI/mL ou em idosos. Distúrbios de condução foram menos prevalentes em idosos com hipotireoidismo subclínico (OR ajustado = 0,44; IC95% 0,24-0,80). Conclusão: Neste grande estudo multicêntrico e transversal, a DST não foi associada a arritmias cardíacas, mas uma avaliação longitudinal é necessária.

Exercise training improves quality of life in women with subclinical hypothyroidism: a randomized clinical trial

ABSTRACT Objective: The aim was to evaluate the quality of life (HRQoL) in women with subclinical hypothyroidism (sHT) after 16 weeks of endurance training. Subjects and methods: In the first phase, a cross-sectional study was conducted in which 22 women with sHT (median age: 41.5 (interquartile range: 175) years, body mass index: 26.2 (8.7) kg/m2, thyroid stimulating hormone > 4.94 mIU/L and free thyroxine between 0.8 and 1.3 ng/dL were compared to a group of 33 euthyroid women concerned to HRQoL. In the second phase, a randomized clinical trial was conducted where only women with sHT were randomly divided into two groups: sHT-Tr (n = 10) - participants that performed an exercise program - and sHT-Sed (n = 10) - controls. Exercise training consisted of 60 minutes of aerobic activities (bike and treadmill), three times a week, for 16 weeks. The HRQoL was assessed by the SF-36 questionnaire in the early and at the end of four months. Results: Women with sHT had lower scores on functional capacity domain in relation to the euthyroid ones (770 ± 23.0 vs. 88.8 ± 14.6; p = 0.020). The sHT-Tr group improved functional capacity, general health, emotional aspects, mental and physical component of HRQoL after training period, while the sHT-Sed group showed no significant changes. Conclusion: After 16 weeks of aerobic exercise training, there were remarkable improvements in HRQoL in women with sHT.

Autopercepção da deglutição em pacientes com doença tireoidiana benigna não cirúrgica / Self-perception of swallowing by patients with benign nonsurgical thyroid disease

RESUMO Objetivo verificar a frequência de queixa para deglutir em pacientes com doença tireoidiana benigna não cirúrgica e comparar a autopercepção de intensidade da alteração de deglutição em diferentes tipos de doença tireoidiana. Método a amostra do estudo foi composta por 39 mulheres com idades entre 19 e 58 anos (38,54 ± 10,74 anos) e diagnóstico de hipotireoidismo (n=22; 56,4%) ou nódulos tireoidianos (n=17; 43,6%). Investigou-se a presença de queixa, tipo de queixa e autopercepção da intensidade da alteração de deglutição por meio da escala analógico-visual de 100 milímetros. Os dados foram analisados de forma descritiva e para comparar a autopercepção entre os diferentes diagnósticos clínicos utilizamos o teste não paramétrico de Mann-Whitney. O nível de significância foi de 5%. Resultados vinte e seis (66,7%) participantes relataram queixa para deglutir. As queixas referidas foram sensação de estase em região laringofaríngea (37,15%), engasgo (34,29%) e odinofagia (28,57%). O valor médio da autopercepção de intensidade da alteração de deglutição por meio da escala analógico-visual foi 59,35 (± 27,38) milímetros. A autopercepção não foi diferente entre os diagnósticos clínicos de doença tireoidiana. Conclusão nessa amostra, queixas para deglutir foram frequentes em mulheres com doenças tireoidianas benignas não cirúrgicas. Essas pacientes percebem a alteração de forma moderada, independentemente do diagnóstico clínico da patologia tireoidiana.

ABSTRACT Purpose To verify the frequency of swallowing complaints in patients with benign nonsurgical thyroid disease and compare the self-perception of swallowing disorder intensity between different types of thyroid disease. Methods The study sample comprised 39 women aged 19-58 years (38.54 ± 10.74) with hypothyroidism (n=22; 56.4%) or thyroid nodules (n=17; 43.6%). Presence and type of swallowing complaint and self-perception of swallowing disorder intensity were investigated by means of self-ratings recorded on a 100-millimeter visual analog scale. The data were analyzed by descriptive measures and the Mann-Whitney nonparametric test was used to compare the self-perception of swallowing disorder intensity between both clinical diagnoses of thyroid disease. The level of 5% was adopted for statistical significance. Results Twenty-six (66.7%) individuals reported the following swallowing complaints: pharyngolaryngeal stasis sensation (37.15%), chocking (34.29%), and odynophagia (28.57%). The mean value of self-perception of swallowing disorder intensity by the visual analog scale was 59.35 (± 27.38) millimeters. No difference in self-perception was reported between the clinical diagnoses of thyroid disease. Conclusion In this sample, swallowing complaint was frequently observed in patients with benign nonsurgical thyroid disease. Moderate self-perception of swallowing disorder intensity was reported regardless of the clinical diagnosis of thyroid disease.

Rastreo de hipotiroidismo en pacientes embarazadas / Hypothyroidism screening in pregnancy

El embarazo es una situación clínica donde se produce un aumento fisiológico de la síntesis de hormona tiroidea y en la cual su carencia puede acarrear morbilidad perinatal. A partir de una viñeta clínica en la cual una médica solicita determinaciones de TSH y hormonas tiroideas a una mujer embarazada asintomática, la autora se plantea la utilidad del rastreo de hipotiroidismo en el embarazo. Luego de realizar una búsqueda bibliográfica y seleccionar la evidencia más reciente y de mejor calidad, se concluye que actualmente no existe sustento para rastrear hipotiroidismo en esta población. Por su parte, diferentes organizaciones recomiendan, a través de sus guías de práctica clínica, la búsqueda de casos teniendo en cuenta factores de riesgo específicos. (AU)

Pregnancy is a clinical condition where there is a physiological increase of thyroid hormone synthesis and in which its deficiency can lead to perinatal morbidity. From a clinical vignette in which a physician requests both TSH and thyroid hormone determinations to an asymptomatic pregnant woman, the author explores the usefulness hypothyroidism scree-ning in pregnancy. After carrying out a bibliographic search and selecting the most recent and best quality evidence, it is concluded that there is currently no firm evidence for sustaining hypothyroidism screening in this population. Although, different organizations recommend through its clinical practice guidelines hypothyroidism case finding in pregnancy taking into account specific risk factors. (AU)

Prevalencia de disfunción tiroidea en pacientes con diabetes mellitus tipo 2 / Prevalence of thyroid dysfunction in patients with type 2 diabetes mellitus

La diabetes mellitus (DM) y la disfunción tiroidea (DT) son dos frecuentes desórdenes endocrinos. La DT subclínica no reconocida puede afectar adversamente el control metabólico y aumentar el riesgo cardiovascular. Nuestro objetivo fue determinar la prevalencia de DT en pacientes con diabetes mellitus tipo 2, en un estudio observacional de corte transversal con evaluación clínica y de laboratorio a 205 pacientes consecutivos atendidos en consulta externa del Centro de Endocrinología, Diabetes y Nutrición de la ciudad de Concepción, Tucumán, Argentina. La disfunción tiroidea se clasificó como hipotiroidismo clínico con TSH > 4.20 μUI/ml y T4L < 0.93 ng/dl; hipotiroidismo subclínico con TSH > 4.20 μUI/ml y T4 libre 0.93 a 1.70 ng/dl. hipertiroidismo subclínico con TSH < 0.27 μUI/ml y T4 libre en rango normal (0.93-1.70 ng/dl). Se consideró hipertiroidismo clínico con TSH < 0.27 μUI/ml y T4 libre > 1.70 μUI/ml. Se diagnosticó autoinmunidad con anti-TPO > 34 UI/ml. La prevalencia de DT en los diabéticos tipo 2 fue 48% (n = 92). En aquellos que negaron DT previa, la prevalencia fue 40% (n = 37), 15 presentaron hipotiroidismo subclínico (45%). En el total de la población estudiada la prevalencia de hipotiroidismo subclínico fue 8%. En forma global la prevalencia de DT subclínica fue 9% (n = 17) y la de anticuerpos anti-TPO 13% (n = 25). La detección temprana de disfunción tiroidea en diabetes mellitus tipo 2 debería realizarse rutinariamente, dada la elevada tasa de nuevos casos diagnosticados y el aumento del riesgo cardiovascular asociado a la disfunción tiroidea no diagnosticada oportunamente.

Diabetes mellitus (DM) and thyroid dysfunction (TD) are two common endocrine disorders. The unrecognized subclinical TD may adversely affect metabolic control and increase cardiovascular risk. Our aim was to investigate the prevalence of TD in patients with type 2 diabetes mellitus in an observational cross-sectional study. Clinical and laboratory evaluation was performed to 205 consecutive outpatients at Endocrinology Diabetes and Nutrition Center in Concepcion City, Tucuman, Argentina. Thyroid dysfunction was classified as clinical hypothyroidism with TSH > 4.20 mUI / ml and FT4 < 0.93 ng / dl, subclinical hypothyroidism with TSH > 4.20 mUI / ml and free T4 0.93 to 1.70 ng / dl. Subclinical hyperthyroidism was considered with TSH < 0.27 mUI / ml and free T4 was in normal range (0.93 to 1.70 ng / dl); and clinical hyperthyroidism with TSH < 0.27 mUI / ml and free T4 >1.70 mUI / ml. Autoimmunity was diagnosed with anti-TPO > 34 IU / ml. TD prevalence in type 2 diabetic patients was 48% (n = 92). In subjects who denied prior TD, the prevalence was 40% (n = 37), 15 with subclinical hypothyroidism (45%). In the whole study population prevalence of subclinical hypothyroidism was 8%. Globally, subclinical DT prevalence was 9% (n = 17) and anti-TPO 13% (n = 25). Early detection of thyroid dysfunction in patients with type 2 diabetes mellitus should be performed routinely, given the high rate of newly diagnosed cases, and increased cardiovascular risk associated with undiagnosed thyroid dysfunction.

Cerebellar ataxia as presenting feature of hypothyroidism

SUMMARY Symptoms and signs of the hypothyroidism vary in relation to the magnitude and acuteness of the thyroid hormone deficiency. The usual clinical features are constipation, fatigue, cold intolerance and weight gain. Rarely it can present with neurologic problems like reversible cerebellar ataxia, dementia, peripheral neuropathy, psychosis and coma. Hypothyroidism should be suspected in all cases of ataxia, as it is easily treatable. A 40 year-old male presented with the history facial puffiness, hoarseness of voice and gait-ataxia. Investigations revealed frank primary hypothyroidism. Anti-TPO antibody was positive. Thyroxine was started and patient improved completely within eight weeks. Hypothyroidism can present with ataxia as presenting feature. Hypothyroidism should be considered in all cases of cerebellar ataxia as it is a reversible cause of ataxia.

Circulating levels of irisin is elevated in hypothyroidism, a case-control study

Objective Our objective in this study was to determine the relationship between irisin hormone, which has a similar effect with thyroid hormones on adipose tissue and the metabolism, and the thyroid functions and the obesity secondary to thyroid disease. Subjects and methods Seventy-four patients were included in the study, of the patients, 37 were newly diagnosed with Hashimoto’s thyroiditis related hypothyroidism but not started on a treatment yet, and the remaining 37 were healthy volunteers without a known disease. Serum thyroid stimulating hormone (TSH), free thyroxin (fT4), anti-thyroglobulin and anti-thyroid peroxidase were measured and thyroid ultrasonography was performed in both groups. Serum irisin levels were measured using the commercially available ELISA kit. The hypothyroidism group had higher levels of irisin compared to the control group (2.77 ng/mL vs. 2.15 ng/mL respectively; p = 0.017). Results The hypothyroidism group had higher median levels of irisin in the obese patients than those in the control group (3.10 ng/mL vs. 2.10 ng/mL respectively; p = 0.013). Irisin level was negatively correlated with age in the whole population and patients with hypothyroidism (r = -0.255, p = 0.028; r = -0.346, p = 0.036 respectively). Irisin level was positively correlated with TSH (r = 0.247, p = 0.034) but negatively correlated with the fT4 (r = -0.316, p = 0.006) in the whole population. Obesity, fT4 and irisin levels were identified to be independent predictors in the diagnosis of hypothyroidism in the multivariable logistic regression analysis. Conclusion To the best of our knowledge, this study is the first in literature to identify that obesity, irisin level and fT4 level are independent risk factors for hypothyroidism.

Co-administration of Apelin and T4 Protects Inotropic and Chronotropic Changes Occurring in Hypothyroid Rats / Coadministração de Apelina e T4 tem Efeito Protetor nas Alterações Inotrópicas e Cronotrópicas que Ocorrem em Ratos Hipotireoideos

AbstractBackground:One of the most important thyroid hormone targets is the cardiovascular system. Hemodynamic changes, such as decreased resting heart rate (HR), myocardial contractility, and cardiac output, and increased diastolic pressure and systemic vascular resistance, have been observed in hypothyroid patients. Moreover, in these patients, ECG changes include sinus bradycardia and low voltage complexes (P waves or QRS complexes).Objective:This study aimed at evaluating the prophylactic effect of apelin on HR changes and QRS voltage that occur in propylthiouracil (PTU)-induced hypothyroid rats.Method:In this study, 48 adult male Wistar rats weighing 170-235g were randomly divided into 6 groups: Control group (normal saline ip injection + tap water gavage); P group (PTU 0.05%, in drinking water); A group (apelin 200 µg.kg-1.day-1, ip); PA group [co-administration of PTU and apelin]; PT group [co-administration of PTU + T4 (0.2 mg/g per day, gavage)]; and PAT group (co-administration of PTU, apelin and T4). All experiments were performed for 28 consecutive days, and then the animals were anesthetized with an ip injection of ketamine (80 mg/kg) and xylazine (12 mg/kg). Lead II electrocardiogram was recorded to calculate HR and QRS voltage.Results:Heart rate and QRS voltage increased more significantly in the hypothyroid group that consumed both apelin and T4 (201 ± 4 beat/min, 0.71 ± 0.02 mv vs. hypothyroid 145 ± 9 beat/min, 0.563 ± 0.015 mv; respectively).Conclusion:The co-administration of apelin and T4 showed a protective effect on QRS voltage and HR in PTU‑induced hypothyroid rats.

ResumoFundamento:O sistema cardiovascular é um dos alvos mais importantes dos hormônios tireoidianos. As seguintes alterações hemodinâmicas foram observadas em pacientes com hipotireoidismo: redução da frequência cardíaca (FC) de repouso, da contratilidade miocárdica e do débito cardíaco; e aumento da pressão diastólica e da resistência vascular sistêmica. Além disso, tais pacientes apresentam alterações eletrocardiográficas, como bradicardia sinusal e baixa voltagem dos complexos (ondas P e complexos QRS).Objetivo:Avaliar o efeito profilático da apelina nas alterações de FC e voltagem de QRS que ocorrem em ratos com hipotireoidismo induzido por propiltiouracil (PTU).Método:Este estudo dividiu de maneira aleatória 48 ratos Wistar machos adultos, pesando 170-235g, em seis grupos: grupo controle (CO), injeção intraperitoneal (ip) de solução salina + água potável gavagem; grupo hipotireoideo (P), PTU 0,05% em água potável; grupo A, apelina ip (200 µg.kg-1.dia-1); grupo PA, coadministração de PTU e apelina; grupo PT, coadministração de PTU e T4, 0.2 mg/g por dia por gavagem; e grupo PAT, coadministração de PTU, apelina e T4. Todos os experimentos foram realizados durante 28 dias consecutivos, sendo então os animais anestesiados com injeção ip de cetamina (80 mg/kg) e xilazina (12 mg/kg). Utilizou-se o registro do ECG na derivação DII para calcular a FC e a voltagem do QRS.Resultados:Houve aumento mais significativo da FC e da voltagem do QRS no grupo hipotireoideo que recebeu apelina e T4 (201±4 bpm, 0,71±0,02mV) do que no hipotireoideo (145±9 bpm, 0,563±0,015 mV), respectivamente.Conclusão:A coadministração de apelina e T4 mostrou efeito protetor na voltagem do QRS e FC em ratos com hipotireoidismo induzido por PTU.

The thyroid hormone receptor β-selective agonist GC-1 does not affect tolerance to exercise in hypothyroid rats

Objective Investigate the effect of GC-1 on tolerance to exercise in rats with experimental hypothyroidism. Materials and methods Hypothyroidism was induced with methimazole sodium and perchlorate treatment. Six groups with eight animals were studied: control group (C), hypothyroid group without treatment (HYPO); hypothyroidism treated with physiological doses of tetraiodothyronine (T4) or 10 times higher (10×T4); hypothyroidism treated with equal molar doses of GC-1 (GC-1) or 10 times higher (10×GC-1). After eight weeks, each animal underwent an exercise tolerance test by measuring the time (seconds), in which the rats were swimming with a load attached to their tails without being submerging for more than 10 sec. After the test, the animals were killed, and blood samples were collected for biochemical analysis, and the heart and soleus muscle were removed for weighing and morphometric analysis of the cardiomyocyte. Results Hypothyroidism significantly reduced tolerance to exercise and, treatment with GC-1 1× or T4 in physiological doses recover tolerance test to normal parameters. However, high doses of T4 also decreased tolerance to physical exercise. Conversely, ten times higher doses of GC-1 did not impair tolerance to exercise. Interestingly, hypothyroidism, treated or not with T4 in a physiological range, GC-1 or even high doses of GC-1 (10X) did not change cardiomyocyte diameters and relative weight of the soleus muscle. In contrast, higher doses of T4 significantly increased cardiomyocyte diameter and induced atrophy of the soleus muscle. Conclusion Unlike T4, GC-1 in high doses did not modify tolerance to physical exercise in the rats with hypothyroidism. .

Association between increased serum thyrotropin concentration and the oldest old: what do we know? / Associação entre aumento da concentração de tirotropina e longevos: o que sabemos?

To assess studies that evaluate the relation between serum thyrotropin concentration, very old subjects, and their events. We searched the PubMed, SciELO, and LILACS databases for articles published between 2004 and 2012. Our search was restricted to studies involving humans aged 65 years or older, and written in English, Spanish, or Portuguese. Studies that evaluated the association between elevated serum thyrotropin concentration among elderly subjects with subclinical hypothyroidism were chosen since at least in part they included a subpopulation of individuals aged 80 years and above. Thirteen studies were selected. No significant increase in risk of cardiovascular events, coronary heart disease, or total mortality was observed. Elevated thyrotropin concentration was associated with longevity. More randomized controlled trials are required to better define the potential benefits of elevated thyrotropin concentration in this oldest old population, hormone replacement, and longevity.

Avaliar os artigos que consideram a relação entre a concentração da tirotropina sérica, indivíduos muito idosos e seus eventos. Foram selecionados artigos do PubMed, SciELO e LILACS publicados entre 2004 e 2012, que consideraram uma população ≥65 anos, escritos em inglês, espanhol ou português. Os estudos que avaliaram a associação entre níveis séricos elevados de tirotropina sérica e idosos com hipotireoidismo subclínico foram escolhidos, desde que incluíssem uma subpopulação com 80 anos ou mais. Treze estudos foram selecionados. Não houve associação significante entre maior risco de eventos cardiovasculares, doença coronariana ou mortalidade. A concentração elevada de tirotropina sérica foi associada à longevidade. Mais estudos randomizados controlados são necessários para o melhor entendimento do potencial benefício da elevação de concentração da tirotropina sérica nos longevos, reposição hormonal e longevidade.

Disfunción tiroidea y corazón / Thyroid dysfunction and heart

Los trastornos de la función tiroidea afectan profundamente al sistema cardiovascular. En esta revisión se presentan algunos aspectos fisiológicos de la interrelación entre tiroides y corazón, como también las consecuencias de la tirotoxicosis e hipotiroidismo sobre el aparato cardiovascular. Se analiza la influencia del hipertiroidismo en la gèc)nesis de la fibrilación auricular y del hipotiroidismo en el metabolismo de las lipoproteínas. Adicionalmente, el artículo se referirá a los potenciales efectos adversos del antiarrítmico amiodarona sobre la función tiroidea y cómo se investigan y tratan. Finalmente, se expone un caso clínico real para ilustrar con mayor claridad la enorme importancia que pueden alcanzar las relaciones fisiopatológicas entre el corazón y las afecciones de esta glándula endocrina.

Disorders of thyroid function profoundly affect the cardiovascular system. Inthisreviewsomephysiologicalaspectsoftherelationship between thyroid and the heart as well as the consequences of thyrotoxicosis and hypothyroidism on the cardiovascular system are presented. The influence of hyperthyroidism is analyzed in the genesis of atrial fibrillation and of hypothyroidism on lipoprotein metabolism. Furthermore, we refer to the potential adverse effects of the antiarrhythmic amiodarone on thyroid function and how they are investigated and treated. Finally, a real clinical case is exposed to more clearly illustrate the enormous importance that can reach the pathophysiological relationships between the heart and the diseases of the thyroid gland.

Prejuízo da vasodilatação muscular durante estresse mental em mulheres com hipotireoidismo subclínico / Impairment of muscle vasodilation during mental stress in women with subclinical hypothyroidism

Objetivo Testar a hipótese de que mulheres com hipotireoidismo subclínico (HSC) possuem condutância vascular do antebraço (CVA) prejudicados durante estresse mental. Sujeitos e métodos Foram avaliadas 20 mulheres com HSC e 21 eutireoidianas (Grupo Controle), pareadas por idade (p = 0,699) e índice de massa corporal (p = 0,462). O fluxo sanguíneo muscular (FSM), avaliado pela pletismografia de oclusão venosa, e a pressão arterial, medida pelo Dixtal2023, foram registrados simultaneamente durante 3 minutos de basal, seguidos de 3 minutos de estresse mental. A CVA foi calculada pela divisão do FSM pela pressão arterial média. Foi adotada significância de p < 0,05. Resultados O grupo HSC apresentou maior concentração do hormônio tireoestimulante (7,57 ± 3,17 vs. 2,10 ± 0,88 mU/L, p < 0,001). No basal, os grupos HSC e Controle foram semelhantes respectivamente para FSM (2,50 ± 0,79 vs. 2,55 ± 0,71 mL/min/100 mL, p = 0,905) e CVA (2,80 ± 0,90 vs. 2,92 ± 0,88 unidades, p = 0,952). Durante todo o estresse mental, os grupos HSC e Controle aumentaram significativamente o FSM (efeito tempo, p < 0,001) e CVA (efeito tempo, p < 0,001) em relação ao basal. Porém, essas variáveis foram significativamente menores no grupo HSC durante o primeiro (FSM: 3,66 ± 0,96 vs. 4,66 ± 1,61 mL/ min/100 mL, p = 0,018; CVA: 3,95 ± 1,08 vs. 5,19 ± 1,96 unidades, p = 0,010) e segundo (FSM: 3,55 ± 1,01 vs. 4,62 ± 2,27 mL/min/100 mL, p = 0,018; CVA: 3,75 ± 1,07 vs. 4,92 ± 2,37 unidades, p = 0,020) minutos do teste de estresse mental. Conclusão Mulheres com HSC possuem comportamento vasodilatador prejudicado durante o estresse mental. .

Objective To test the hypothesis that women with subclinical hypothyroidism (SH) have forearm vascular conductance (FVC) impaired during mental stress. Subjects and methods We evaluated 20 women with SH and 21 euthyroid (Control group), matched for age (p = 0.699) and body mass index (p = 0.462). Muscle blood flow (MBF) was assessed by venous occlusion plethysmography and blood pressure by Dixtal2023. Both variables were recorded simultaneously for 3 minutes of baseline followed by 3 minutes of mental stress. The FVC was calculated by dividing MBF by mean arterial pressure. Significant differences were assumed at p < 0.05. Results The SH group had higher concentrations of thyroid stimulating hormone (7.57 ± 3.17 vs. 2.10 ± 0,88 mU/L, p < 0.001). At baseline, the SH and control groups were similar for MBF (2.50 ± 0.79 vs. 2.55 ± 0,71 mL/ min/100 mL, p = 0.905, respectively) and FVC (2.80 ± 0.90 vs. 2.92 ± 0.88 units, p = 0.952, respectively). Throughout the mental stress test the SH and Control groups increased the MBF (time effect, p < 0.001) and FVC (time effect, p < 0.001) compared to baseline protocol. However, these variables were lower in SH group during the first (MBF: 3.66 ± 0.96 vs. 4.66 ± 1,61 mL/min/100 mL, p = 0.018, FVC: 3.95 ± 1.08 vs. 5.19 ± 1,96 units, p = 0.010) and second (MBF: 3.55 ± 1.01 vs. 4.62 ± 2,27 mL/min/100 ml, p = 0.018; FVC: 3.75 ± 1.07 vs. 4.92 ± 2,37 units, p = 0.020) minutes of mental stress test. Conclusion Women with SH have reduced muscle vasodilatatory response during mental stress. .

Hypothalamic-pituitary-ovarian axis in thyroid dysfunction / El eje hipotalámico-pituitario-ovárico en la disfunción tiroidea

BACKGROUND: It has been established that thyroid dysfunction causes impairment of reproductive function. However, laboratory and human studies that associated this with female reproductive hormones are conflicting and data reporting the effects of thyroid dysfunction on reproductive organs are insufficient. AIM: This study investigated the effect of experimental hypothyroidism and hyperthyroidism on hypothalamic-pituitary-ovarian axis and reproductive organs morphometry and histology in female rats. METHODS: Laboratory animals were randomized into one of the three groups: control, carbimazole-induced hypothyroidism and levothyroxine-induced hyperthyroidism. RESULTS: Organ morphometry and serum follicle stimulating hormone (FSH) were statistically comparable across all groups. Serum progesterone increased in hypothyroid rats but was reduced in hyperthyroid rats when compared with the control (p < 0.05). Body weight gain, serum luteinizing hormone and oestradiol were significantly reduced in both hypothyroid and hyperthyroid states when compared to the control. Hypothyroidism and hyperthyroidism also led to alterations in organ cytoarchitecture. CONCLUSION: Findings from this study suggest that impairment ofreproductive function associated with thyroid dysfunction is attendant with derangement of hormonal milieu and alteration in reproductive organs cytoarchitecture. Luteinizing hormone and oestradiol are implicated.

ANTECEDENTES: Se ha establecido que la disfunción de la tiroides causa deterioro de la función reproductiva. Sin embargo, los estudios humanos y de laboratorio que asociaban tal disfunción a las hormonas reproductoras femeninas son contradictorios, y los datos que reportan los efectos de la disfunción tiroidea sobre los órganos reproductores son insuficientes. OBJETIVO: Este estudio investigó el efecto del hipotiroidismo y el hipertiroidismo experimentales sobre el eje hipotalámico-pituitario-ovárico, y la morfometría e histología de los órganos reproductores en ratas hembras. MÉTODOS: Los animales de laboratorio fueron asignados al azar a uno de estos tres grupos: control, hipotiroidismo inducido por carbimazol, e hipertiroidismo inducido por levotiroxina. RESULTADOS: La morfometría de los órganos y hormona folículo-estimulante (FSH) en suero, fueron estadísticamente comparables en todos los grupos. La progesterona sérica aumentó en las ratas hipotiroideas, pero se redujo en las ratas hipertiroideas en comparación con el grupo de control (p < 0.05). El aumento de peso corporal, la hormona luteinizante en suero, y el estradiol se redujeron significativamente tanto en condiciones de hipotiroidismo como en estado de hipertiroidismo, en comparación con el grupo control. El hipotiroidismo y el hipertiroidismo condujeron también a alteraciones en la citoarquitectura de los órganos. CONCLUSIÓN: Resultados de este estudio sugieren que la debilitación de la función reproductora asociada con la disfunción de la tiroides, va acompañada de trastornos del medio hormonal, e implica alteraciones de la citoarquitectura de los órganos reproductores, la hormona luteinizante, y el estradiol.

Evaluation of thyroid function and autoimmunity in HIV-infected women / Avaliação da função tiroidiana e autoimunidade em mulheres infectadas pelo HIV

Autoimmune thyroid diseases (AITD) are the main causes of thyroid dysfunction and the most common autoimmune diseases in the world. An association between AITD and infections with the human immunodeficiency virus (HIV), in combination with the effects of highly active anti-retroviral therapy (HAART), has been suggested by several research groups. The aim of the present study was to evaluate the frequency of thyroid dysfunction and AITD in women > 35 years of age infected with HIV, and to identify factors associated with the emergence of these thyroid abnormalities. HIV-infected women (n = 153) selected from the infectious disease outpatient clinic at a University Hospital in Rio de Janeiro were characterized based on their circulating CD4+ lymphocytes levels, viral loads, serum TSH levels, and the presence of FT4 and anti-thyroperoxidase antibodies (TPO-Ab). A total of 129 participants were on HAART and 24 were not. The frequency of thyroid disorders was 7.8% (12/153 patients) and all were on HAART at the time of diagnosis, yielding a prevalence of 9.3% in patients receiving HAART compared with 0% in patients not on HAART. AITD, hyper, and hypothyroidism were detected in 4.6%, 3.1%, and 4.1% of HAART patients. It was not detected any thyroid dysfunction or autoimmunity in HIV-infected women not on HAART. This study demonstrated an association between HAART and the development of AITD. In addition AITD only developed in HAART patients also presenting with undetectable viral loads and slightly elevated CD4+ T cell counts.

Doenças tiroidianas autoimunes (DTAI) são a maior causa de disfunção tiroidiana e são as doenças autoimunes mais comuns no mundo. A associação entre DTAI e infecções com o vírus da imunodeficiência humana (HIV), em combinação com a terapia antirretroviral altamente ativa (HAART), foi sugerida por vários grupos de pesquisadores. O objetivo do presente estudo foi avaliar a fre-quência de disfunção tiroidiana e DTAI em mulheres com mais 35 anos de idade infectadas com o HIV e identificar fatores associados com a emergência dessas anormalidades tiroidianas. As mulheres infectadas com HIV (n = 153), selecionadas do ambulatório de doenças infecciosas de um hospital universitário do Rio de Janeiro, foram caracterizadas com base no nível de linfócitos CD4+ circulantes, carga viral, níveis de TSH sérico e presença de anticorpos FT4 e antitiroperoxidase (TPO-Ab). Um total de 129 participantes se tratava com HAART e 24 não. A frequência de desordens da tiroide foi 7,8% (12/153 pacientes) e todas estavam em tratamento com HAART no momento do diagnóstico, levando a uma prevalência 9,3% em pacientes recebendo HAART, em comparação com 0% em pacientes não tratadas com HAART. DTAI, hipertireoidismo e hipotireoidismo foram detectados em 4,6%, 3,1% e 4,1% das pacientes tratadas com HAART. Não foram detectadas disfunção tiroidiana ou autoimunidade em mulheres infectadas com HIV e não tratadas com HAART. Este estudo demonstrou uma associação entre a HAART e o desenvolvimento de DTAI. Além disso, a DTAI apenas se desenvolveu em pacientes tratadas com HAART e que apresentavam cargas virais indetectáveis e contagens de células CD4+ T levemente elevadas.