Flow-Mediated, Endothelium-Dependent Vasodilatation Is Impaired in Subjects with Hypothyroidism, Borderline Hypothyroidism, and High-Normal Serum Thyrotropin (TSH) Values

Lekakis, John; Papamichael, Christos; Alevizaki, Maria; Piperingos, Gregorios; Marafelia, P.; Mantzos, J.; Stamatelopoulos, Stamatios; Koutras, Demetrios A.

doi:10.1089/thy.1997.7.411

Cited by 217 publications

(146 citation statements)

References 15 publications

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“…in auto-immune hypothyroidism), the change in coagulation parameters could be more pronounced. Our findings demonstrate that thyroid hormone deficiency may be associated with significant alterations of hemostasis due to a decrease in VWF:Ag, VWF:CBA, and FVIII:C. Hypothyroidism (overt or subclinical) could also be associated with increased cardiovascular risk, although the mechanisms are not clearly defined (25)(26)(27). This association could be explained through the endothelial dysfunction described in hypothyroidism, which plays a major role in the development of atherosclerosis in addition to classical cardiovascular risk factors.…”

Section: Discussionmentioning

confidence: 78%

Evaluation of the respective influence of thyroid hormones and TSH on blood coagulation parameters after total thyroidectomy

Yango¹,

Alexopoulou²,

Eeckhoudt

et al. 2011

European Journal of Endocrinology

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Background: Several hemostatic abnormalities have been described in hypothyroidism, such as modification of coagulation proteins and bleeding tendency. Although thyroid hormone deficiency is considered to be responsible for these changes, the underlying mechanisms have not yet been established. Objective: To evaluate the respective influence of peripheral thyroid hormones (free thyroxine) and TSH on blood clotting by assessing coagulation parameters in patients with a history of total thyroidectomy for thyroid cancer, under three different conditions: induced hypothyroidism, euthyroid state, and following recombinant human TSH (rhTSH) administration. Methods: Coagulation parameters (platelet count, fibrinogen, international normalized ratio, prothrombin time, thrombin time, activated partial thromboplastin time (APTT), factor VIII activity ((FVIII:C), as well as von Willebrand factor antigen (VWF:Ag) and VWF activity using collagen binding assay (VWF:CBA)) were measured in patients with severe hypothyroidism following withdrawal of thyroid hormone replacement therapy, and in the same patients with euthyroidism after restoring replacement treatment (group A), and before and after administering rhTSH (group B). Results: FVIII:C, VWF:Ag, and VWF:CBA were significantly decreased (P!0.001), whereas APTT was significantly increased (P!0.001) in patients with severe hypothyroidism compared with patients in the euthyroid state. No changes in clotting parameters were observed in patients who received rhTSH therapy.Conclusion: This prospective study shows that severe short-term hypothyroidism is associated with significantly lower levels of VWF:Ag, VWF:CBA, and FVIII:C. Administration of exogenous TSH has no effect on coagulation parameters. These findings suggest that thyroid hormone deficiency is likely to be the main cause of coagulation alterations in patients with hypothyroidism.

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Section: Discussionmentioning

confidence: 78%

Evaluation of the respective influence of thyroid hormones and TSH on blood coagulation parameters after total thyroidectomy

Yango¹,

Alexopoulou²,

Eeckhoudt

et al. 2011

European Journal of Endocrinology

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“…(8) Existem evidências de que ao haver acoplamento dos hormônios tireoideanos nas células endoteliais há liberação de substâncias vasoconstritoras como a endotelina-1 (40) , e vasodilatadoras como a adrenomedulina (41) e óxido nítrico. (42) Em estudo com 65 indivíduos com hipotireoidismo clínico foi observado que a concentração de TSH esteve positivamente correlacionada com a rigidez arterial.…”

Section: Potenciais Contribuições Do Exercício Físico Nas Disfunções unclassified

“…(44) Investigações apontam que os níveis elevados de TSH também podem prejudicar a função endotelial. (45) Em hipotireoideos subclínicos, Lekakis et al (8) demonstraram uma correlação negativa entre esta doença e a vasodilatação dependente do endotélio. Taddei et al (22) corroboram com estes dados, além de apontarem que em hipotireoideos subclínicos há também reduzida biodisponibilidade do óxido nítrico, potente vasodilatador liberado pelo endotélio, e que após terapia de reposição hormonal com levotiroxina, há aumento significante da vasodilatação.…”

Section: Potenciais Contribuições Do Exercício Físico Nas Disfunções unclassified

“…(2) Além das repercussões clássicas no metabolismo, o hipotireoidismo está relacionado também com disfunções cardiovasculares, que podem ser explicadas pelo fato de haver receptores dos hormônios tireoidianos nas células miocárdicas e endoteliais. (1,(4)(5) As disfunções cardiovasculares já são observadas no hipotireoidismo subclínico (2) , pois, uma produção inadequada de TSH tem sido associada com maiores valores de pressão arterial sistólica e diastólica (6) , disfunção endotelial (7)(8) , estresse oxidativo (9) e desbalanço simpatovagal. (10)(11)(12) O exercício físico tem sido indicado como tratamento não farmacológico para doenças crônico-degenerativas como a hipertensão arterial, o diabetes e a obesidade.…”

Section: Introductionunclassified

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Influência do exercício físico nas alterações cardiovasculares induzidas pelo hipotireoidismo

Souza¹,

Lima²,

Nóbrega³

et al. 2012

RBAFS

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ResumoO hipotireoidismo é uma disfunção da tireóide que não produz seus hormônios ou só o faz através de uma alta produção do hormônio tireoestimulante. Essa enfermidade está associada ao desenvolvimento de disfunções cardiovasculares diversas. Esta revisão traz à comunidade científica e aos profissionais da saúde, informações atualizadas sobre as repercussões cardiovasculares do hipotireoidismo, sua influência na capacidade para o exercício físico, e o potencial do exercício físico para minimizar ou restaurar estas disfunções. Um levantamento dos estudos publicados entre 1995 e 2011 foi conduzido na base de dados PubMed utilizando os descritores: physical exercise, blood pressure, cardiovascular, vascular endothelial, oxidative stress, autonomic nervous system, cardiac function, subclinical hypothyroidism e hypothyroidism. Foram considerados, os artigos que avaliaram a função cardiovascular de hipotireoideos subclínicos e clínicos, e a influência do exercício físico sobre as funções cardiovasculares afetadas nesta doença. Verificamos que a capacidade aeróbia de hipotireoideos subclínicos e clínicos está reduzida, e que a função endotelial, o estresse oxidativo e a função autonômica estão prejudicados nestes sujeitos. O exercício físico parece ser capaz de restaurar a função endotelial, apesar de não fazer o mesmo na disfunção autonômica. Não existem investigações associando o efeito do exercício físico na função cardíaca e no estresse oxidativo. Apesar de ser uma enfermidade tão prevalente quanto o diabetes, não existe uma recomendação para a prescrição de exercício físico para os hipotireoideos, tal como há para obesos, cardiopatas e diabéticos. Perspectivas sobre como avançar no conhecimento da prescrição do exercício físico são apresentadas. Palavras-chaveHipotireoidismo; Exercício físico; Sistema cardiovascular. Abstract Hypothyroidism is a disorder of the thyroid gland that does not produce its hormones or only does in response to a high production of thyroid-stimulating hormone. This disease is associated with the development of various cardiometabolic disorders. This review brings to the scientific community and health professionals, updated information about the cardiovascular effects of hypothyroidism, its influence on physical

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“…We recently reported that intima-media thickness (IMT) in the common carotid artery, a good predictor for cardiovascular events (10,11), is increased in hypothyroid patients, and that increased IMT normalized after one year of levothyroxine (L-T4) replacement therapy (12). Accelerated atherosclerosis in hypothyroidism is accounted for by multiple mechanisms, including hyperlipidemia (13), hypercoagulable state (14), impaired endothelium-dependent vasodilation (15) and obesity (16). However, since there is no data on serum OPG levels in hypothyroidism, it is of importance to assess the possible involvement of OPG in the increased arterial thickening in hypothyroidism.…”

Section: Introductionmentioning

confidence: 99%

Increased levels of serum osteoprotegerin in hypothyroid patients and its normalization with restoration of normal thyroid function

Nagasaki¹,

Inaba²,

Jono³

et al. 2005

eur j endocrinol

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Hypothyroidism is associated with increased morbidity from cardiovascular disease, and an increase in serum osteoprotegerin (OPG) has recently been reported to be associated with the severity of coronary heart disease and cardiovascular mortality. The present study was designed to examine whether hypothyroidism causes an increase in serum OPG, and to determine whether levothyroxine (L-T4) replacement therapy might suppress serum OPG levels in hypothyroid patients. Fifty-three hypothyroid patients with chronic thyroiditis and age-and sex-matched normal control subjects were examined for the levels of serum OPG and plasma von Willebrand factor (vWF), a vascular injury marker. Thirty-seven of the hypothyroid patients were further monitored for changes in these markers during 1 year in a euthyroid state induced by L-T4 replacement therapy. Baseline OPG was significantly higher in hypothyroid patients than in normal controls (4.51^0.50 vs 3.72^0.23 pmol/l (mean^S.E.); P ¼ 0.0182). In multivariate analysis, baseline OPG was significantly associated with baseline levels of TSH (r ¼ 0.280, P ¼ 0.0162) and vWF (r ¼ 0.626, P , 0.0001). During one year of L-T4 replacement therapy, hypothyroid patients showed a significant decrease in OPG levels from 4.35^0.51 to 3.48^0.26 pmol/l (P ¼ 0.0166), a level comparable to normal controls. The change in serum OPG levels during L-T4 replacement therapy was significantly and independently associated in a negative fashion with baseline vWF (r ¼ 2 0.503, P ¼ 0.0014). This study suggested that the severity of hypothyroidism and vascular injury might have important independent roles in increasing the serum OPG level in hypothyroid patients. Furthermore, it was demonstrated that a sustained euthyroid state might have the potential to decrease the serum OPG level in hypothyroid patients and that the degree of vascular injury in the hypothyroid state is independently associated with a decrease in serum OPG during a 1-year normalization of thyroid function.

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Flow-Mediated, Endothelium-Dependent Vasodilatation Is Impaired in Subjects with Hypothyroidism, Borderline Hypothyroidism, and High-Normal Serum Thyrotropin (TSH) Values

Cited by 217 publications

References 15 publications

Evaluation of the respective influence of thyroid hormones and TSH on blood coagulation parameters after total thyroidectomy

Evaluation of the respective influence of thyroid hormones and TSH on blood coagulation parameters after total thyroidectomy

Influência do exercício físico nas alterações cardiovasculares induzidas pelo hipotireoidismo

Increased levels of serum osteoprotegerin in hypothyroid patients and its normalization with restoration of normal thyroid function

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