Deciphering the roles of triiodothyronine (T3) and thyroid-stimulating hormone (TSH) on cardiac electrical remodeling in clinical and experimental hypothyroidism

Hypothyroidism is the most frequent endocrine pathology. Although clinical or overt hypothyroidism has been traditionally associated to low T3 / T4 and high thyrotropin (TSH) circulating levels, other forms exist such as subclinical hypothyroidism, characterized by normal blood T3 / T4 and high TSH. In its different forms is estimated to affect approximately 10% of the population, especially women, in a 5:1 ratio with respect to men. Among its consequences are alterations in cardiac electrical activity, especially in the repolarization phase, which is accompanied by an increased susceptibility to cardiac arrhythmias. Although these alterations have traditionally been attributed to thyroid hormone deficiency, recent studies, both clinical trials and experimental models, demonstrate a fundamental role of TSH in cardiac electrical remodeling. Thus, both metabolic thyroid hormones and TSH regulate cardiac ion channel expression in many and varied ways. This means that the different combinations of hormones that predominate in different types of hypothyroidism (overt, subclinic, primary, central) can generate different forms of cardiac electrical remodeling. These new findings are raising the relevant question of whether serum TSH reference ranges should be redefined. (AU)

Deciphering the roles of triiodothyronine (T3) and thyroid-stimulating hormone (TSH) on cardiac electrical remodeling in clinical and experimental hypothyroidism

Hypothyroidism is the most frequent endocrine pathology. Although clinical or overt hypothyroidism has been traditionally associated to low T3 / T4 and high thyrotropin (TSH) circulating levels, other forms exist such as subclinical hypothyroidism, characterized by normal blood T3 / T4 and high TSH. In its different forms is estimated to affect approximately 10% of the population, especially women, in a 5:1 ratio with respect to men. Among its consequences are alterations in cardiac electrical activity, especially in the repolarization phase, which is accompanied by an increased susceptibility to cardiac arrhythmias. Although these alterations have traditionally been attributed to thyroid hormone deficiency, recent studies, both clinical trials and experimental models, demonstrate a fundamental role of TSH in cardiac electrical remodeling. Thus, both metabolic thyroid hormones and TSH regulate cardiac ion channel expression in many and varied ways. This means that the different combinations of hormones that predominate in different types of hypothyroidism (overt, subclinic, primary, central) can generate different forms of cardiac electrical remodeling. These new findings are raising the relevant question of whether serum TSH reference ranges should be redefined. (AU)

Circulating concentrations of free triiodothyronine are associated with central adiposity and cardiometabolic risk factors in young euthyroid adults

Thyroid dysfunction is associated with classic cardiometabolic risk factors in humans. However, this relationship remains unclear in young euthyroid adults. The present work examines the associations of circulating thyroid hormones (THs) and thyroid-stimulating hormone (TSH) concentrations with body composition and cardiometabolic risk factors in young euthyroid adults. A total of 106 sedentary, euthyroid adults (72 women; 22 ± 2 years old) participated in this cross-sectional study. THs and TSH serum concentrations were determined in fasting conditions (6 h). Body composition (fat mass (FM), lean mass (LM), and visceral adipose tissue (VAT)) was determined by dual-energy X-ray absorptiometry, anthropometric parameters (weight, height, and waist circumference) were measured, and neck adipose tissue mass was quantified through computed tomography (CT) scanning. Cardiometabolic risk factors including fasting glucose and lipid metabolism markers, hepatic phosphatase and transaminases, and blood pressure were also assessed. Free triiodothyronine (FT3) concentration was positively associated with body mass index, LM, VAT, and waist circumference (all P ≤ 0.038). FT3 was also associated with glucose, insulin, HOMA-IR, fatty liver index, and blood pressure (all P < 0.024). All the associations were attenuated when adjusting for sex. In contrast, we found no associations of TSH or free thyroxine with any body composition parameter or cardiometabolic risk factors. In conclusion, FT3 is associated with central adiposity and cardiometabolic risk factors including insulin resistance, fatty liver index, and mean, systolic and diastolic blood pressure in young euthyroid adults. ClinicalTrials.gov identifier: NCT02365129. (AU)

Hipotiroidismo consuntivo en paciente con hipotiroidismo primario previo / Consumptive hypothyroidism in patient with previous primary hypothyroidism

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Valores de referencia de hormonas tiroideas en la población de gestantes en Lugo / Reference values of thyroid hormones in the population of pregnant in Lugo

ANTECEDENTES Y OBJETIVO: La compleja fisiología de la función tiroidea durante el embarazo requiere la evaluación hormonal según valores de referencia para cada trimestre, cada zona y con las técnicas de cada laboratorio. Los objetivos de este estudio fueron analizar la función tiroidea en los tres trimestres de gestación y establecer los valores de referencia de las hormonas en las mujeres gestantes de nuestra área sanitaria (Lugo). MÉTODOS: Un total de 831 gestantes fueron incluidas en el estudio (mediana de edad: 33años; rango: 16-47años). Una vez aplicados los criterios de exclusión, nuestra muestra estuvo compuesta por 641 gestantes, tamaño que puede considerarse representativo de la población de referencia. RESULTADOS: Los intervalos de referencia fueron los siguientes: TSH primer trimestre, 0,10-3,74mUI/l; segundo trimestre, 0,45-3,77mUI/l; y tercer trimestre, 0,36-4,15mUI/l. Para T4L en el primer trimestre, 0,87-1,34ng/dl; segundo trimestre, 0,78-1,20ng/dl; y tercer trimestre, 0,78-1,23ng/dl. Para la T3L en el primer trimestre, 2,52-3,78pg/ml; segundo trimestre, 2,22-3,21pg/ml; y tercer trimestre, 2,17-3,14pg/ml. Se confirmó presencia de autoinmunidad tiroidea en 109 mujeres (13,1%), que presentaron valores de TSH superiores a las gestantes sin autoinmunidad tiroidea. CONCLUSIÓN: Los intervalos de referencia para la TSH, T4L y T3L obtenidos en este trabajo están por debajo de los utilizados en la población adulta no gestante en nuestro laboratorio, por lo que permitirán identificar de manera más precisa una posible disfunción tiroidea en las gestantes de nuestra área evitando un infradiagnóstico de hipotiroidismo subclínico y reduciendo las posibles complicaciones perinatales asociadas

BACKGROUND AND OBJECTIVE: The complex physiology of thyroid function during pregnancy requires a hormonal evaluation according to reference values for each trimester, each area, and with the techniques of each laboratory. The objectives of this study were to analyse thyroid function in the three trimesters of pregnancy and to establish the reference values of hormones in pregnant women in this health area (Lugo). METHODS: A total of 831 pregnant women were included in the study (median age: 33years, age range: 16-47years). Once the exclusion criteria were applied, the sample consisted of 641 pregnant women, a size that can be considered representative of the reference population. RESULTS: The reference intervals were as follows: TSH first trimester, 0.10-3.74mIU/L; second trimester, 0.45-3.77mIU/L; and third trimester, 0.36-4.15mIU/L. For Free T4 in the first trimester, 0.87-1.34ng/dL; second trimester, 0.78-1.20ng/dL; and third trimester, 0.78-1.23ng/dL. For Free T3 in the first trimester, 2.52-3.78pg/mL; second trimester, 2.22-3.21pg/mL; and third trimester, 2.17-3.14pg/mL. The presence of thyroid autoimmunity was confirmed in 109 women (13.1%), who presented with higher TSH values than pregnant women without thyroid autoimmunity. CONCLUSION: The reference intervals for TSH, Free T4, and Free T3 obtained in this study are below those used in the non-pregnant adult population in this laboratory. This should help to identify more accurately a possible thyroid dysfunction in pregnant women in the study area, avoiding an underdiagnosis of subclinical hypothyroidism and reducing the possible associated perinatal complications

Prevalencia y valor pronóstico del síndrome del enfermo eutiroideo en niños críticos / Prevalence and prognostic value of non-thyroidal illness syndrome among critically ill children

Introducción: Se ha sugerido que las alteraciones en las hormonas tiroideas ocurridas en pacientes con enfermedad crítica, fenómeno conocido como síndrome del enfermo eutiroideo (SEE), pueden tener valor pronóstico. No obstante, los datos en población pediátrica son escasos. El objetivo del estudio fue evaluar la prevalencia y el valor pronóstico del SEE en niños críticos. Materiales y métodos: Estudio prospectivo observacional en 70 niños críticos ingresados en la unidad de cuidados intensivos pediátricos (UCIP). Se determinaron los niveles de triyodotironina libre (T3L), tiroxina libre (T4L) y tirotropina (TSH) en las primeras 24 horas de ingreso. La variable de resultado principal fue la mortalidad a los 30 días. Resultados: Se observó SEE en el 62,9% de los pacientes, aunque adoptó formas diversas. El patrón más frecuente fue un nivel bajo de T3L con niveles normales de T4L y TSH (25,7% de los pacientes). La combinación de valores bajos de T3L, T4L, y TSH ocurrió en el 7,1% de los pacientes. Hubo un hallazgo inusual de TSH elevada en 3 pacientes que podría estar asociado a la gravedad de la enfermedad. Los valores bajos de T4L se observaron con una frecuencia significativamente mayor en pacientes fallecidos en comparación con supervivientes (50% versus 19,2%, p = 0,028). El SEE predijo la mortalidad de manera independiente (OR = 3,91; IC 95% = 1,006-15,19; p = 0,0491). La combinación de niveles bajos de T3L, T4L, y TSH fue el mejor factor pronóstico independiente de mortalidad (OR = 16,9; IC 95% = 1,40-203,04; p = 0,026). Se observó una correlación negativa entre la TSH y la duración de la estancia en la UCIP (rs = -0,35; p = 0,011). El valor de T3L fue significativamente menor en pacientes tratados con perfusión de dopamina, comparados con pacientes que no la recibieron (2,1 ± 0,66 versus 2,76 ± 0,91 pg/ml, p = 0,011). Conclusión: El SEE es común en niños críticos y parece estar asociado a la mortalidad y la gravedad de la enfermedad

Introduction: Alterations in thyroid hormones during critical illness, known as non-thyroidal illness syndrome (NTIS), were suggested to have a prognostic value. However, pediatric data is limited. The aim of this study was to assess prevalence and prognostic value of NTIS among critically ill children. Materials and methods: A prospective observational study conducted on 70 critically ill children admitted into pediatric intensive care unit (PICU). Free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) were measured within 24 hours of PICU admission. Primary outcome was 30-day mortality. Results: NTIS occurred in 62.9% of patients but it took several forms. The most common pattern was low FT3 with normal FT4 and TSH (25.7% of patients). Combined decrease in FT3, FT4, and TSH levels occurred in 7.1% of patients. An unusual finding of elevated TSH was noted in three patients, which might be related to disease severity. Low FT4 was significantly more prevalent among non-survivors compared with survivors (50% versus 19.2%, P = .028). NTIS independently predicted mortality (OR = 3.91; 95% CI = 1.006-15.19; P = .0491). Concomitant decrease in FT3, FT4, and TSH was the best independent predictor of mortality (OR = 16.9; 95% CI = 1.40-203.04; P = .026). TSH was negatively correlated with length of PICU stay (rs = -0.35, P = .011). FT3 level was significantly lower among patients who received dopamine infusion compared with those who did not receive it (2.1 ± 0.66 versus 2.76 ± 0.91 pg/mL, P = .011). Conclusion: NTIS is common among critically ill children and appears to be associated with mortality and illness severity

Prevalencia del síndrome complejo de malnutrición e inflamación y su correlación con las hormonas tiroideas en pacientes en hemodiálisis crónica / Prevalence of malnutrition-inflammation complex syndrome and its correlation with thyroid hormones in chronic haemodialysis patients

Introducción: La reducción de las hormonas tiroideas, triyodotironina total (T3) y triyodotironina libre (T3L) en pacientes en hemodiálisis, es un marcador de malnutrición e inflamación y son predictores de mortalidad. El objetivo del estudio fue determinar la prevalencia del síndrome complejo de malnutrición e inflamación en hemodiálisis y su asociación con las hormonas tiroideas: tirotropina, T3, T3L y tiroxina libre (T4L); además de evaluar la incidencia del síndrome de T3L y su correlación con marcadores nutricionales e inflamatorios. Materiales y métodos: Estudio transversal, analítico y comparativo, incluyó 128 pacientes en HD, 50,8% mujeres, edad 45,05±17,01 años, 45,4±38,8 meses en hemodiálisis, 29,7% diabéticos y 79,7% hipertensos. Se determinó en suero la concentración de tirotropina, T3, T3L y T4L, se aplicó la encuesta Malnutrition-Inflammation Score para diagnosticar malnutrición e inflamación. Resultados: La media de valores de las hormonas tiroideas fueron: tirotropina 2,48±1,8 mUI/mL (rango 0,015-9,5), T3 1,18±0,39ng/mL (0,67-2,64), T3L 5,21±0,96pmol/l (3,47-9,75), T4L 1,35±0,4ng/mL (0,52-2,57). La prevalencia de síndrome complejo de malnutrición e inflamación es 53,9%; un 11,7% mostró T3L baja. Las concentraciones séricas de T3 y T3L correlacionan negativamente con Malnutrition-Inflammation Score y T4L correlaciona positivamente con Malnutrition-Inflammation Score. El análisis de regresión lineal de T3L baja fue asociado con IL-6 (β=0,265 p=0,031), proteína C reactiva (β=-0,313 p=0,018) y albúmina (β=0,276 p=0,002). Conclusiones: Bajos niveles de T3 y T3L correlacionan con parámetros de inflamación y nutrición. El síndrome complejo de malnutrición e inflamación puede afectar la concentración sérica de hormonas tiroideas (AU)

Introduction: Low levels of thyroid hormones, total triiodothyronine (T3) and free triiodothyronine (FT3) in haemodialysis patients is a marker of malnutrition and inflammation and are predictors of mortality. The aim of this study was to determine the prevalence of malnutrition-inflammation complex syndrome in haemodialysis and its relationship with the thyroid hormones thyrotropin, T3, FT3 and free thyroxine (FT4), as well as to evaluate the prevalence of low FT3 syndrome and its correlation with nutritional and inflammatory markers. Materials and methods: Cross-sectional, analytical and comparative study that enrolled 128 haemodialysis patients: 50.8% females; mean age 45.05±17.01 years; mean time on haemodialysis 45.4±38.8 months; 29.7% diabetics; 79.7% with hypertension. Serum thyroid hormones thyrotropin, T3, FT3 and FT4 concentrations were measured and Malnutritition-Inflammation Score (MIS) was applie to diagnostic. Results: Mean thyroid hormone values were: thyroid hormones thyrotropin 2.48±1.8 mIU/ml (range: 0.015-9.5), T3 1.18±0.39 ng/ml (range 0.67-2.64), FT3 5.21±0.96pmol/l (range: 3.47-9.75); FT4 1.35±0.4 ng/ml (range: 0.52-2.57). Malnutrition-inflammation complex syndrome prevalence was 53.9%; 11.7% presented low FT3 levels. Serum T3 and FT3 concentrations inversely correlated with Malnutritition-Inflammation Score (MIS), while FT4 correlated positively with Malnutrition-Inflammation Score. In the linear regression analysis, low FT3 was associated with IL-6 (β= 0.265, p=.031), C-reactive protein (CRP) (β= -0.313, p=.018) and albumin (β= 0.276, p=.002). Conclusion: Low T3 and FT3 levels are correlated with malnutrition and inflammation parameters. Malnutrition-inflammation complex syndrome can affect serum concentrations of thyroid hormones (AU)

La disminución de triyodotironina se asocia con la elevación del péptido natriurético cerebral N-terminal y con la mortalidad en pacientes en diálisis / Low triiodothyronine is associated with elevation of N-terminal pro-brain natriuretic peptide (NT-proBNP) and mortality in dialysis patients

Antecedentes: La disminución de hormonas tiroideas (HT) y el daño miocárdico son frecuentes en pacientes en diálisis y están asociados con la mortalidad. Sin embargo, poco se conoce de la importancia de las HT como factor de daño miocárdico, como se ha descrito en las enfermedades tiroideas primarias. El objetivo de este estudio fue explorar si existe interacción entre la disminución de triyodotironina total (tT3) y los marcadores de daño miocárdico y la relación de esta interacción entre ambos con la mortalidad, para establecer si el daño cardiovascular es el vínculo entre la disminución de HT y el riesgo de muerte en pacientes con ERC en diálisis. Material y métodos: Se estudiaron los niveles plasmáticos de HT, de marcadores de nutrición, inflamación y de daño al miocardio en 296 pacientes en diálisis peritoneal o en hemodiálisis, a los que se vigiló por 16 meses para conocer la asociación de las variables bioquímicas con la mortalidad. Resultados: En el 45% de los pacientes se encontró tT3 disminuida, lo cual tuvo correlación inversa con la proteína C reactiva (PCR) y con el NT-proBNP y directa con la albúmina y la transferrina. La diabetes, la PCR y la tT3 fueron factores de riesgo para la mortalidad por cualquier causa y la PCR, el NT-proBNP y la tT3 para mortalidad cardiovascular. Conclusiones: Los niveles bajos de tT3 son frecuentes en pacientes en diálisis, se asocian con inflamación, desnutrición y daño miocárdico: este último puede ser el vínculo entre la disminución de HT y la mortalidad por cualquier causa y la mortalidad cardiovascular (AU)

Background: Low thyroid hormone (TH) levels and myocardial damage are common in dialysis patients and are associated with mortality. However, little is known about the role of THs on myocardial damage as has been described in primary thyroid diseases. The aim of this study was to explore the potential relationship between low total triiodothyronine (total T3) and biomarkers of myocardial damage and the effect of their interaction on mortality, to ascertain if cardiovascular damage is the link between low THs and the risk of death in dialysis patients with CKD. Material and methods: TH plasma levels, nutritional markers, inflammation and myocardial damage were studied in 296 patients undergoing peritoneal dialysis or haemodialysis, who were followed up for 16 months to ascertain the association between biochemical variables and mortality. Results: Low total T3 levels were found in 45% of patients, which was inversely correlated with C-reactive protein (CRP) and NT-proBNP, and directly correlated with albumin and transferrin. Diabetes, CRP and total T3 were risk factors for all-cause mortality, and CRP, NT-proBNP and total T3 for cardiovascular mortality. Conclusions: Low total T3 levels are common in dialysis patients and are associated with inflammation, malnutrition and myocardial damage. The latter may be the link between low THs and all-cause and cardiovascular mortality (AU)

Biopsia selectiva del ganglio centinela en el carcinoma papilar de tiroides en pacientes sin evidencia preoperatoria de metástasis ganglionar / Selective sentinel lymph node biopsy in papillary thyroid carcinoma in patients with no preoperative evidence of lymph node metastasis

Introducción: La linfadenectomía en la cirugía del carcinoma papilar de tiroides se aconseja cuando hay evidencia de metástasis ganglionar cervical (terapéutica) o en pacientes de alto riesgo (profiláctica), como en los tumores T3 y T4 de la clasificación TNM. La técnica de la biopsia selectiva del ganglio centinela puede mejorar el diagnóstico prequirúrgico de las metástasis ganglionares. Objetivo: Analizar el resultado de la biopsia selectiva del ganglio centinela en un grupo de pacientes con carcinoma papilar de tiroides T sin evidencia de afectación ganglionar antes de la cirugía. Pacientes y método: Estudio retrospectivo, unicéntrico en el que se incluyeron los pacientes intervenidos entre los años 2011-2013 que fueran clínicamente N0. La identificación del ganglio centinela se realizó mediante técnica isotópica. En todos los casos, se practicó linfadenectomía del compartimento afecto si el ganglio centinela era positivo, y del compartimento central en caso de ganglio centinela negativo. Resultados: Se incluyeron 43 pacientes, 34 mujeres, con una edad media de 52,3 (±17) años. De los 170 ganglios centinela resecados, 46 (27%) fueron positivos para metástasis, que correspondían a 24 (55,8%) pacientes. En las linfadenectomías se resecaron 612 ganglios. De ellos, 96 (15,6%) fueron positivos para metástasis. Doce de los treinta (40%) pacientes cT1N0 y cT2N0 pasaron a pN1 tras la biopsia selectiva del ganglio centinela, mientras que 12 de los 13 (92%) pacientes cT3N0 y cT4N0, acabaron siendo pN1. Conclusiones: La biopsia selectiva del ganglio centinela recalifica más del 50% de pacientes de cN0 a pN1. Se confirma la necesidad de vaciamiento ganglionar en los tumores T3 y T4, pero pone al descubierto la presencia de metástasis linfáticas en el 40% de los T1-T2 (AU)

Introduction: Lymphadenectomy is recommended during surgery for papillary thyroid carcinoma when there is evidence of cervical lymph node metastasis (therapeutic) or in high-risk patients (prophylactic) such as those with T3 and T4 tumors of the TNM classification. Selective sentinel lymph node biopsy may improve preoperative diagnosis of nodal metastases. Objective: To analyze the results of selective sentinel lymph node biopsy in a group of patients with papillary thyroid carcinoma and no evidence of nodal involvement before surgery. Patients and method: A retrospective, single-center study in patients with papillary thyroid carcinoma and no clinical evidence of lymph node involvement who underwent surgery between 2011 and 2013. The sentinel node was identified by scintigraphy. When the sentinel node was positive, the affected compartment was removed, and when sentinel node was negative, central lymph node dissection was performed. Results: Forty-three patients, 34 females, with a mean age of 52.3 (±17) years, were enrolled. Forty-six (27%) of the 170 SNs resected from 24 (55.8%) patients were positive for metastasis. In addition, 94 (15.6%) out of the 612 lymph nodes removed in the lymphadenectomies were positive for metastases. Twelve of the 30 (40%) low risk patients (cT1N0 and cT2N0) changed their stage to pN1, whereas 12 of 13 (92%) high risk patients (cT3N0 and cT4N0) changed to pN1 stage. Conclusions: Selective sentinel lymph node biopsy changes the stage of more than 50% of patients from cN0 to pN1. This confirms the need for lymph node resection in T3 and T4 tumors, but reveals the presence of lymph node metastases in 40% of T1-T2 tumors (AU)

Limitations of current thyroid function tests / Limitaciones de las pruebas actuales de la función tiroidea

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Síndrome del enfermo eutiroideo como factor de riesgo para mortalidad en el paciente crítico / Euthyroid sick syndrome as a risk factor for mortality in critically ill patients

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An evidence for the transcriptional regulation of iodothyronine deiodinase 2 by progesterone in ovarectomized rats

Recent literature lacks studies on the effects of progesterone withdrawal on peripheral conversion of thyroxin (T4) into triiodothyronine (T3) by iodothyronine deiodinase 2 (D2) in different body tissues. The present study aimed to assess the possible relation of progesterone to T4, T3, and D2 in ovarectomized rats. Thirty female Wistar rats were included into a sham-operated control group and an ovarectomized group. Four months following the surgical procedures, measurements of estradiol, progesterone, free T4, free T3, and thyroid-stimulating hormone (TSH) were done. Also, estradiol/progesterone and T4/T3 ratios were calculated. Tissue homogenates from the kidney, liver, brain, thyroid, mandible, and femur were used to assess expression of D2 mRNA. The estradiol/progesterone ratio showed a significant increase in ovarectomized rats. T4 showed a significant increase in contrast to T3 which showed a highly significant decrease following ovariectomy. The T4/T3 ratio was significantly increased in ovarectomized rats. In addition, D2 expression was significantly attenuated in all tissue homogenates of the ovarectomized group. The present work showed a significant positive correlation between T4 and T3 in the sham-operated control rats, which was abolished in ovarectomized rats. A negative significant correlation between progesterone and T4 was revealed in ovarectomized rats. There was also a significant positive correlation between progesterone and D2 expression in the ovarectomized group. The results of the present study hypothesize that progesterone withdrawal may underlie the decrement in D2 expression, with consequent reduction in the peripheral conversion of T4 into T3 leading to a hypothyroid state

Modificaciones Inmediatas en el Flujo Sanguíneo Periférico tras la aplicación de una Manipulación T3-T4 en Mujeres Fumadoras / Immediate changes in the peripheral blood flow after applying a T3-T4 manipulation to smoking women

Introducción: Nuestra investigación se centra en mujeres fumadoras, para valorar los efectos del thrust en el sexo femenino, y comprobar si la nicotina podía ser un factor de variación en el flujo sanguíneo de esta población. Objetivos: Comprobar si con manipulación con «Dog Technique» (MDT) en extensión del segmento vertebral T3-T4 se produce un cambio de la frecuencia cardíaca, presión arterial y/o del flujo sanguíneo de la arteria radial, carótida y pedia. Material y Métodos: Se estudiaron a 25 fumadoras , con edades entre los 18 y los 50 años, sin patología cardiovascular previa, distribuidas en dos grupos experimental (n=13; edad media 36,15 ± 8,34 años ) y control (n=12; edad media 34,67 ± 6,95 años). Se les aplicó una técnica de manipulación torácica («Dog Technique») en extensión bilateral en el segmento espinal T3-T4 y se midió la frecuencia cardíaca, la presión arterial y el flujo sanguíneo de las arterias radial, carótida y pedia bilateral. Resultados: Existen diferencias intergrupales significativas entre el GE y GC en la velocidad sistólica (p=0,034) y la velocidad media (p=0,038) de la arteria radial derecha. En cuanto a la frecuencia cardiaca, presión sistólica y diastólica, obtuvimos una disminución inmediata en sus valores tras la aplicación de la técnica experimental, pero no hubo diferencias significativas entre los grupos (p>0,05). Conclusiones: La aplicación de la técnica MDT en extensión del segmento vertebral T3-T4 en mujeres fumadoras consigue un aumento significativo del flujo en la arteria radial derecha, y una tendencia significativa en la arteria carótica izquierda. No existen cambios significativos en el flujo de la arteria pedia, ni en los valores de frecuencia cardiaca, presión sistólica y diastólica (AU)

Introduction: Our research is focused on smoking women, in order to evaluate thrust's effects in female gender and verify if nicotine could represent a factor of varying the blood flow of this population. Objectives: Verify if using Manipulation with Dog Technique (MDT) in extension of the vertebral segment T3-T4, there is a change produced in the heart rate, blood pressure and/or the blood flow of the radial, carotid or the dorsalis pedis artery. Material and methods: 25 smoking women were analysed, aged between 18 and 50, with no previous cardiovascular disease. They were divided into two groups, the Experimental Group (n=13; average age 36.15±8.34 years) and the Control Group (n=12; average age 34.67±6.95 years). A thoracic manipulative technique (Dog technique) was applied in bilateral extension of the spinal segment T3-T4, and heart rate, blood pressure and blood flow of the radial, carotid and dorsalis pedis artery were measured. Results: There are significant intergroup differences between the CG and the EG with regard to the systolic velocity (p=0.034) and the mean velocity (p=0.038) of the right radial artery. As for the heart rate and the systolic and diastolic pressure, we obtained an immediate decrease of their values after applying the experimental technique, but there were no significant differences between groups (p>0.05). Conclusions: Applying the MDT technique in extension of the vertebral segment T3-T4, on smoking women, obtains a significant increase of the flow in the right radial artery and a significant tendency in the left carotid artery. There are no significant changes, neither in the flow of dorsalis pedis artery, nor in the values of the heart rate and systolic and diastolic pressure (AU)

Changes of activity and kinetics of certain liver and heart enzymes of hypothyroid and T3-treated rats

Thyroid diseases are one of the most common metabolic disorders in the human population. In this work, we present data concerning changes in the activity and kinetic parameters of several enzymes associated with both anabolic (glucose-6-phosphate dehydrogenase-G6PDH, EC 1.1.1.49; 6-phosphogluconate dehydrogenase-6PGDH, EC 1.1.1.44; malic enzyme-ME, EC 1.1.1.40; and isocitrate dehydrogenase-IDH, EC 1.1.1.42) and catabolic (NAD-dependent malate dehydrogenase-NAD-MDH, EC 1.1.1.37; and lactate dehydrogenase-LDH, EC 1.1.1.27) processes under conditions of hypothyroidism and T3 treatment. Hypothyroidism was induced in rats by the surgical removal of the thyroid gland. T3-treated rats were injected by T3 (0.5 mg T3/kg body weight daily during 10 days). We have found that T3 treatment caused an increase of NAD-MDH activity as well as heart hypertrophy whereas the activity of LDH increased in the direction of pyruvate reduction. Moreover, we observed increased activity of both enzymes in the liver. These results confirm earlier observation concerning the relevance of oxidative metabolism in the heart under T3 treatment. Hypothyroidism resulted in changes in the LDH activity in the heart whereas NAD-MDH activity did not change. Moreover, our data show that T3 treatment caused an increase of G6PDH, 6PGDH, and ME activities in the liver. We also observed a decrease of IDH activity in both organs, whereas hypothyroidism caused the opposite effect. This data indicate that either deficiency or excess of thyroid hormones can prove to be particularly dangerous for the physiology of the heart muscle by disturbing bioenergetic and anabolic processes (AU)

Hipotiroidismo en tratamiento en el Área de Salud de Guadalajara (España): características y prevalencia estimadas a partir del consumo de hormona tiroidea / Hypothyroidism under treatment in the Guadalajara (Spain) health care area: characteristics and prevalence based on the intake of thyroid hormone

Objetivo. Nos proponemos estimar la prevalencia del hipotiroidismo tratado en nuestra Área de Salud a partir de la prescripción de hormona tiroidea. Describimos asimismo sus características y diferencias en base a diversos factores sociodemográficos. Diseño. Estudio descriptivo de corte transversal. Emplazamiento. Área Sanitaria de Guadalajara (España). Participantes. Sujetos en tratamiento con levotiroxina por hipotiroidismo incluidos en tarjeta sanitaria durante el año 2009. Mediciones Principales. Se evaluaron la distribución por sexo, edad y lugar de residencia, previo ajuste de tasas. Otras variables analizadas fueron el tipo de hipotiroidismo, última dosis prescrita y niveles de TSH, comparando en función de variables sociodemográficas. Resultados. Un 3,3% de la población (IC 95%: 3,3-3,4) recibió tratamiento con levotiroxina (5,8% mujeres y 1,0% varones), observando la tasa más elevada en mujeres mayores de 65 años (11,9%). La tasa ajustada fue 38,8/1000 (IC 95%: 37,7-40,0) para el medio urbano y 34,6/1000 (IC 95%: 33,4-35,8) para el rural. Edad media de 56,6 años (DE: 18,2). Se asume origen autoinmune en el 76% de los casos con causa reconocible, utilizando una dosis media de 76,84mcg/día. Un 76,2% de los pacientes presentaron un rango correcto de TSH. Conclusiones. El hipotiroidismo subclínico es un proceso frecuente entre los usuarios de un Centro de Salud y mayoritariamente tiene origen autoinmune. El diagnóstico es más frecuente en el sexo femenino y en población mayor. Existe habitualmente un buen control de las cifras de TSH. Las diferencias geográficas son poco relevantes(AU)

Objective. It is our aim to estimate the prevalence of hypothyroidism treated in our health care area from the prescription of thyroid hormone. Likewise, we describe its characteristics and differences on the basis of various socio-demographic factors. Design. Cross sectional descriptive-type study. Location. Guadalajara (Spain) health care area. Participants. Subjects under treatment with levothyroxine for hypothyroidism included on health card throughout the year 2009. Main Measures. Distribution by gender, age and place of residence, after rate adjustment. Other analyzed variables were the type of hypothyroidism, last prescribed dosage and TSH levels, compared according to socio-demographic variables. Results. 3,3% of the population (IC 95%: 3,3-3,4) were treated with levothyroxine (5,8% female y 1,0% male), with the highest rate being seen in women over 65 years old (11,9%). The adjusted rate was 38,8/1000 (IC 95%: 37,7-40,0) for urban areas and 34,6/1000 (IC 95%: 33,4-35,8) for rural areas. Average age 56,6 years (DE: 18,2). An autoimmune origin is assumed in 76% of cases with a recognizable cause, using an average dose of 76,84mcg/day. 76,2% of the patients showed a correct level TSH. Conclusions. Subclinical hypothyroidism is a frequent complaint among Health Centre users and has a chiefly autoimmune origin. Diagnosis is more frequent in females and in older members of the population. TSH figures are usually closely checked. Geographical differences of little significance(AU)

Sindromes de resistencia a las hormonas tiroideas / Thyroide hormone resistance syndromes

La resistencia a hormonas tiroideas es un grupo de sindromes de causa genetica caracterizados por la disminucion de la sensibilidad tisular a estas hormonas. En la actualidad se distinguen tres formas, en los que la resistencia a la accion hormonal se debe, respectivamente, a mutaciones del gen que codifica el receptor nuclear de T3 TRbeta, a alteraciones en el transporte celular de T4 y T3, y a defectos en la conversion de T4 en T3 mediada por desyodasas. En esta revision se hace una exposicion resumida y actualizada de cada una de estas tres formas de resistencia y se discuten los mecanismos patogonicos y aproximaciones clinicas (AU)

Thyroid hormone resistance syndromes are a group of genetic conditions characterized by decreased tissue sensitivity to thyroid hormones. Three syndromes, in which resistance to hormone action is respectively due to mutations in the gene encoding for thyroid hormone receptor TR¦Â, impaired T4 and T3 transport, and impaired conversion of T4 to T3 mediated by deiodinases. An updated review of each of these forms of resistance is provided, and their pathogenetic mechanisms and clinical approaches are discussed (AU)

Valores de referencia de hormonas tiroideas en la población de mujeres gestantes de Jaén / Reference values for thyroid hormones in the population of pregnant women in jaen (Spain)

Objetivo Valorar la función tiroidea en los tres trimestres de gestación en mujeres sanas suplementadas con yodo y definir los límites de referencia de la normalidad de esta población. Diseño Estudio descriptivo sobre la mujer gestante para definir los límites de normalidad de hormonas tiroideas en esta población. Emplazamiento Jaén y Osuna. Población Gestantes sanas. Métodos Determinación de hormonas tiroideas en los tres trimestres de gestación en mujeres sanas suplementadas con yodo. Resultados Cuatrocientas veintinueve gestantes fueron suplementadas con yodo para mantener nivel de yoduria en los límites de normalidad. Las concentraciones de T4-l estuvieron entre 0,60 y 1,06 para el primer trimestre, entre 0,43 y 0,85 ng/dl en el segundo trimestre y entre 0,40 y 0,82 ng/dl en el tercer trimestre. Para la TSH los valores de referencia son: 0,23 y 4,18μUI/ml en el primer trimestre, 1,78 y 3,89μUI/ml en el segundo trimestre y 2,01 y 4,30μUI/ml en el tercer trimestre. Para T3-l los límites en el primer trimestre es de 2,33 a 3,84 pg/ml, entre 2,04 y 3,51 pg/ml en el segundo trimestre y entre 1,99 y 3,46 pg/ml en el tercer trimestre. ConclusiónLos límites de referencia para nuestra población teniendo en cuenta los percentiles 3 y 97 están muy por debajo del recomendado por nuestro laboratorio de referencia, lo que obliga a redefinir estas concentraciones para evitar diagnosticar de forma incorrecta de hipotiroxinemia a la mujer gestante sana (AU)

Objective: To evaluate thyroid function in the three trimesters of pregnancy in healthy women taking iodine and to define the reference ranges of normality in this population. Design: Descriptive study of pregnant women to define the ranges of normality of thyroid hormones in this population. Setting: Jaen and Osuna (Spain).Population: Healthy pregnant women. Methods: Thyroid hormone determination in the three trimesters of pregnancy in healthy women taking iodine supplements. Results: A total of 429 pregnant women taking iodine supplements to maintain urinary iodine levels within the normal range were included. T4-l levels were between 0.60 and 1.06 in the first trimester, between 0.43 and 0.85 ng/dl in the second and between 0.40 and 0.82 ng/dl in thethird. Thyroid stimulating hormone (TSH) reference values were between 0.23 and 4.18 UI/mlin the first trimester, 1.78 and 3.89 UI/ml in the second and 2.01 and 4.30 UI/ml in the third.T3-l values were between 2.33 and 3.84 pg/ml in the first trimester, between 2.04 and 3.51pg/ml in the second and between 1.99 and 3.46 pg/ml in the third. Conclusion: Bearing the 3rd and 97th percentiles in mind, the reference ranges in our population were far below those recommended by our reference laboratory. In view of these results, these values should be redefined to avoid incorrect diagnoses of hyperthyroxinemia in healthypregnant women (AU)

Serum free triiodothyronine (T3) to free thyroxine (T4) ratio in treated central hypothyroidism compared with primary hypothyroidism and euthyroidism

T he standard treatment of hypothyroidism (central and primary) consists of thyroxine (T4) administration alone. However, the normal thyroid gland produces a small proportion of triiodothyronine (T3) directly into the circulation. Aim We aimed to study the free T3 to free T4 ratio in treated central hypothyroidism compared with euthyroidism and treated primary hypothyroidism. Methods Eighty-three subjects were included in this cross-sectional study: 36 with central hypothyroidism, 20 with primary hypothyroidism and 27 healthy controls. A clinical history and a physical examination, including height and weight measurement, were performed and body mass index (BMI) was calculated. Fasting blood was drawn to measure T3, T4, free T3, free T4 and TSH. Results The free T3 to free T4 ratio was lower in treated central hypothyroidism than in euthyroidism but was similar to treated primary hypothyroidism. Free T4 was higher in treated central and primary hypothyroidism than in euthyroidism. Age, sex and BMI did not affect the free T3 to free T4 ratio. Conclusions Treated patients with central hypothyroidism had a lower free T3 to free T4 ratio, similar free T3 levels and higher free T4 concentrations than euthyroid controls, whereas all these parameters were similar in central and primary hypothyroid patients treated with T4. The question of whether these findings translate into adequate tissue concentrations of free thyroid hormones in all tissues remains to be answered. Further studies should aim to determine whether clinical outcomes could be improved by a treatment achieving more physiological plasma concentrations (AU)

El tratamiento habitual del hipotiroidismo (central y primario) consiste en administrar sólo tiroxina (T4). Sin embargo, la glándula tiroides normal produce una proporción pequeña de triyodotironina (T3) que va directamente a la circulación. Objetivo Estudiar la razón entre las concentraciones de T3 /T4 circulantes en el hipotiroidismo central tratado respecto al eutiroidismo y al hipotiroidismo primario también tratado. Métodos Se incluyeron 83 sujetos en este estudio transversal: 36 presentaban hipotiroidismo central, 20 hipotiroidismo primario y 27 eran controles sanos. Se realizó una historia clínica y una exploración física que incluía la altura y el peso, y se calculó el índice de masa corporal (IMC). Se extrajo sangre en ayunas para medir T3, T4, T3 libre, T4 libre y TSH. Resultados La razón T3/T4 circulantes fue inferior en el hipotiroidismo central que en el eutiroidismo, pero similar a la del hipotiroidismo primario. La T4 libre fue mayor en el hipotiroidismo central y en el primario que en el eutiroidismo. La edad, el sexo y el IMC no afectaron la razón T3 /T4 circulante. Conclusiones Los pacientes con hipotiroidismo central tratados presentan una razón T3/T4 circulante más baja, niveles de T3 circulante similares y concentraciones de T4 libre superiores a los controles eutiroideos; sin embargo, todos estos parámetros son similares en los pacientes con hipotiroidismo central y primario tratados con T4. No se sabe si esto se traduce en concentraciones tisulares adecuadas de hormonas tiroideas libres en todos los tejidos. Queda por investigar si un tratamiento que obtenga una concentración plasmática más fisiológica sería mejor desde el punto de vista de los resultados clínicos. Es de esperar que se diseñen estudios en esa dirección (AU)

Disfunción tiroidea en las pacientes abortadoras. ¿Existen argumentos para el cribado? / Thyroid dysfunction in patients who miscarry. Is screening justified?

Objetivos. La normal función tiroidea es esencial para el adecuado desarrollo maternofetal durante el embarazo. Existe una sólida evidencia científica en relación con los efectos indeseables de la disfunción tiroidea sobre el embarazo, la madre y el feto. Uno de ellos es el padecimiento de aborto espontáneo y pérdidas gestacionales recurrentes. Aun así, no existe acuerdo sobre la conveniencia de cribar estas alteraciones en la embarazada, incluso cuando existe historia previa de los efectos adversos referidos. Objetivos. En el presente trabajo hemos intentado determinar la prevalencia de disfunción tiroidea (incluyendo autoinmunidad sin anormalidad en las determinaciones de T3/T4/TSH), en pacientes afectadas por aborto espontáneo. Sujetos y métodos. Se determinó T3-T4-TSH y anticuerpos anti-tiroglobulina/tiroperoxidasa en el momento del diagnóstico a 132 pacientes consecutivas con aborto espontáneo. Resultados. Casi un 25% de las pacientes padecían una disfunción tiroidea, desconocida y no tratada. Conclusión. Parece existir una mayor prevalencia de disfunción tiroidea entre las pacientes que padecen aborto espontáneo en nuestro medio, respecto de lo previamente comunicado (AU)

Objectives. Normal thyroid function is crucial for adequate maternal and fetal development in pregnancy. There is solid evidence of the pernicious effects of thyroid dysfunction in pregnancy for both mother and fetus. One of these effects is miscarriage and recurrent pregnancy losses. Nevertheless, there is no general agreement on the advisability of screening for thyroid dysfunction in pregnant women, even when there is a previous history of pregnancy loss. This study aimed to determine the prevalence of thyroid dysfunction (including anti-thyroid autoimmunity without abnormal T3/T4/TSH levels) in patients with spontaneous abortion. Subjects and methods. T3-T4-TSH-antithyroid antibodies (thyroglobulin and thyroperoxidase) were determined at diagnosis in 132 consecutive women with spontaneous miscarriage. Results. Nearly 25% of the patients had undiagnosed and untreated thyroid disturbance. Conclusion. The results obtained suggest that the prevalence of thyroid dysfunction in patients with spontaneous miscarriage is higher than previously reported in our environment (AU)