scholarly journals Effects of Substitution and High-Dose Thyroid Hormone Therapy on Deiodination, Sulfoconjugation, and Tissue Thyroid Hormone Levels in Prolonged Critically Ill Rabbits

Endocrinology ◽  
2008 ◽  
Vol 149 (8) ◽  
pp. 4218-4228 ◽  
Author(s):  
Yves Debaveye ◽  
Björn Ellger ◽  
Liese Mebis ◽  
Theo J. Visser ◽  
Veerle M. Darras ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Hormone Therapy ◽  
Critically Ill ◽  
Kidney Tissue ◽  
High Dose ◽  
Reverse T3 ◽  
Hormone Levels ◽  
Liver And Kidney ◽  
Thyroid Hormone Levels ◽  
The Impact

To delineate the metabolic fate of thyroid hormone in prolonged critically ill rabbits, we investigated the impact of two dose regimes of thyroid hormone on plasma 3,3′-diiodothyronine (T2) and T4S, deiodinase type 1 (D1) and D3 activity, and tissue iodothyronine levels in liver and kidney, as compared with saline and TRH. D2-expressing tissues were ignored. The regimens comprised either substitution dose or a 3- to 5- fold higher dose of T4 and T3, either alone or combined, targeted to achieve plasma thyroid hormone levels obtained by TRH. Compared with healthy animals, saline-treated ill rabbits revealed lower plasma T3 (P = 0.006), hepatic T3 (P = 0.02), and hepatic D1 activity (P = 0.01). Substitution-dosed thyroid hormone therapy did not affect these changes except a further decline in plasma (P = 0.0006) and tissue T4 (P = 0.04). High-dosed thyroid hormone therapy elevated plasma and tissue iodothyronine levels and hepatic D1 activity, as did TRH. Changes in iodothyronine tissue levels mimicked changes in plasma. Tissue T3 and tissue T3/reverse T3 ratio correlated with deiodinase activities. Neither substitution- nor high-dose treatment altered plasma T2. Plasma T4S was increased only by T4 in high dose. We conclude that in prolonged critically ill rabbits, low plasma T3 levels were associated with low liver and kidney T3 levels. Restoration of plasma and liver and kidney tissue iodothyronine levels was not achieved by thyroid hormone in substitution dose but instead required severalfold this dose. This indicates thyroid hormone hypermetabolism, which in this model of critical illness is not entirely explained by deiodination or by sulfoconjugation.

scholarly journals Novel uses of thyroid hormones in cardiovascular conditions

Endocrine ◽  
2019 ◽  
Vol 66 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Salman Razvi
Keyword(s):  
Cardiovascular Diseases ◽  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Hormone Therapy ◽  
Large Scale ◽  
Experimental Studies ◽  
Hormone Treatment ◽  
Limited Data ◽  
Hormone Levels ◽  
Thyroid Hormone Levels

Abstract Thyroid hormone levels are reduced in cardiovascular diseases and this phenomenon is associated with worse outcomes. It is unclear whether the changes in thyroid hormone bioavailability to the affected myocardium are beneficial or if this is a maladaptive response. Experimental studies from animal models of acute myocardial infarction (AMI) suggest that thyroid hormone treatment may be beneficial. There is limited data available on the use of thyroid hormones in patients with AMI and heart failure and this suggests that treatment to normalise thyroid hormone levels may be safe and potentially efficacious. Similarly, evidence of thyroid hormone therapy in patients undergoing cardiac surgery or during cardiac transplantation is limited. It is therefore difficult to draw any firm conclusions about benefits or risks of thyroid hormone treatment in these conditions. Large scale clinical trials of thyroid hormones in patients with cardiac conditions are required to confirm safety and evaluate efficacy. Furthermore, it needs to be elucidated which hormone to administer (thyroxine or triiodothyronine), when in the disease pathway to treat, dose of thyroid hormone to administer, and which parameters to utilise to assess safety and efficacy. Until these important questions are answered thyroid hormone therapy in cardiovascular diseases must remain within the research domain.

scholarly journals The impact of thyroid hormone dysfunction on ischemic heart disease

2019 ◽  
Vol 8 (5) ◽  
pp. R76-R90 ◽  
Author(s):  
Madalena von Hafe ◽  
João Sergio Neves ◽  
Catarina Vale ◽  
Marta Borges-Canha ◽  
Adelino Leite-Moreira
Keyword(s):  
Heart Disease ◽  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Ischemic Heart Disease ◽  
Left Ventricular ◽  
Ischemic Heart ◽  
Hormone Levels ◽  
Thyroid Axis ◽  
Thyroid Hormone Levels ◽  
The Impact

Thyroid hormones have a central role in cardiovascular homeostasis. In myocardium, these hormones stimulate both diastolic myocardial relaxation and systolic myocardial contraction, have a pro-angiogenic effect and an important role in extracellular matrix maintenance. Thyroid hormones modulate cardiac mitochondrial function. Dysfunction of thyroid axis impairs myocardial bioenergetic status. Both overt and subclinical hypothyroidism are associated with a higher incidence of coronary events and an increased risk of heart failure progression. Endothelial function is also impaired in hypothyroid state, with decreased nitric oxide-mediated vascular relaxation. In heart disease, particularly in ischemic heart disease, abnormalities in thyroid hormone levels are common and are an important factor to be considered. In fact, low thyroid hormone levels should be interpreted as a cardiovascular risk factor. Regarding ischemic heart disease, during the late post-myocardial infarction period, thyroid hormones modulate left ventricular structure, function and geometry. Dysfunction of thyroid axis might even be more prevalent in the referred condition since there is an upregulation of type 3 deiodinase in myocardium, producing a state of local cardiac hypothyroidism. In this focused review, we summarize the central pathophysiological and clinical links between altered thyroid function and ischemic heart disease. Finally, we highlight the potential benefits of thyroid hormone supplementation as a therapeutic target in ischemic heart disease.

Age Moderates the Impact of TRAbs on Thyroid Hormones and Hepatic Function in Patients with Graves’ Disease

2021 ◽  
Vol 53 (07) ◽  
pp. 453-460
Author(s):  
Kai Guo ◽  
Hongwei Ling ◽  
Xiaoyan Zhou ◽  
Changjiang Ying
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Hepatic Function ◽  
Graves Disease ◽  
Newly Diagnosed ◽  
Younger Patients ◽  
Hormone Levels ◽  
Thyroid Hormone Levels ◽  
Antibody Levels ◽  
The Impact

AbstractThyrotropin receptor antibodies (TRAbs) play a significant role in the course of hepatic dysfunction (HDF) in patients with Graves’ disease (GD). However, few studies have considered the factors that influence the relationships among TRAbs, thyroid hormone levels, and hepatic function in subjects with newly diagnosed GD. Here we investigated the associations of TRAbs with thyroid hormones and hepatic function and assessed potential factors that can influence these associations among patients with GD. A total of 368 patients newly diagnosed with GD were collected in this cross-sectional study. Patients who had received antithyroid drugs, radioactive iodine, or surgery were excluded. Levels of TRAbs and thyroid hormones and hepatic function were recorded. Linear and binary logistic regression analysis models were applied to investigate associations among these variables after adjusting for confounding characteristics. There was a significant difference in TRAbs indices between the HDF and normal hepatic function groups (p <0.05). After adjusting for confounders, the relationship between TRAbs and thyroid hormones was nonlinear, showing a curve with an initial positive slope and a subsequent flattening (p <0.05). Higher TRAbs were associated with HDF [odds ratio (OR) 1.036, 95% confidence interval (CI) 1.018–1.053 per 1-IU/l increase]. These associations were modified by age, but not by gender, smoking status, Graves’ orbitopathy, thyroid-peroxidase antibody levels, or thyroglobulin antibody levels. In younger patients, increasing TRAbs were correlated with higher thyroid hormones and HDF (OR 1.034, 95% CI 1.017–1.052) per1-IU/l increase). In older patients, TRAbs were not correlated with thyroid hormones or HDF (OR 1.024, 95% CI 0.993–1.056) per 1-IU/l increase. Age can affect the impact of TRAbs on thyroid hormone levels and hepatic function in GD. TRAb measurement can have good predictive value in younger patients.

scholarly journals Longitudinal Study of Thyroid Hormones between Conventional and Organic Farmers in Thailand

Toxics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 82
Author(s):  
Noppanun Nankongnab ◽  
Pornpimol Kongtip ◽  
Nichcha Kallayanatham ◽  
Ritthirong Pundee ◽  
Jutharak Yimsabai ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Longitudinal Impact ◽  
Free Triiodothyronine ◽  
Hormone Levels ◽  
Endocrine Disrupting ◽  
Organic Farmers ◽  
Thyroid Hormone Levels ◽  
The Impact

Many pesticides are endocrine-disrupting chemicals that can interfere with hormone levels. This study aimed to assess the longitudinal impact of exposure to pesticides on thyroid hormone levels, including Thyroid Stimulating Hormone (TSH), Free Triiodothyronine (FT3), Free Thyroxine (FT4), Triiodothyronine (T3), and Thyroxine (T4). Both conventional (i.e., pesticide using) and organic farmers were interviewed using questionnaires, and blood samples were collected at 7–9 a.m. to determine thyroid hormone levels for four rounds, with a duration of eight months between each round. A linear mixed model of the natural log of the individual hormone levels used random intercepts for subjects while controlling gender, baseline age, and body mass index (BMI) was used to compare between conventional and organic farmers or the impact of cumulative days of spraying insecticides, herbicides or fungicides. The estimated marginal means of the thyroid hormone levels (TSH, FT3, T3, and T4) estimated from the linear mixed models were significantly higher among the conventional farmers than organic farmers. As cumulative spray days of insecticide, herbicide or fungicide increased, TSH and FT3 increased significantly. FT4 decreased significantly as cumulative spray days of insecticide or fungicide increased. These findings suggest that the insecticides, herbicides, and fungicides sprayed by conventional farmers exert endocrine-disrupting activities, altering the hypothalamic-pituitary-thyroid (HPT) axis homeostasis.

scholarly journals Correlation of Thyroid Hormones in the Prognosis of Critically Ill Patients

2021 ◽  
Vol 73 (3) ◽  
pp. 161-166
Author(s):  
Sneha R. Chavanda ◽  
Rajendra R. Mane
Keyword(s):  
Intensive Care ◽  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Apache Ii ◽  
Apache Ii Score ◽  
Hormone Levels ◽  
Thyroid Hormone Levels ◽  
Thyroid Profile

Objective: Non-thyroidal illness syndrome (NTIS) is associated with outcomes in Intensive Care Unit(ICU) patients. The objectives of the study were to assess the prognostic value of complete thyroid profile in critically ill patients and to determine the effect of thyroid hormone level in predicting mortality when used along with acute physiology and chronic health evaluation (APACHE) II score.Methods: The observational study was conducted at a tertiary care centre in Kolhapur, India. Critically ill adult patients admitted to intensive care units with APACHE II >10 was included(n=50). Relevant clinical investigations along with thyroid profile evaluation was carried out and APACHE II was calculated.  Baseline characteristics of patients were compared.  Performance of variables in predicting mortality was analysed. Correlation of APACHE II score with thyroid was also assessed in R software v-3.6.1.Results: The survival rate at ICU discharge was 54%. Mean T3, FT3, and T4 levels were significantly low in non-survivors(p=0.006758, p=0.0245 and p=0.00070 respectively).  Mean APACHE II score was significantly high in non- survivor(p=2.94E-06). APACHE II score was significantly associated with the severity of disease (p=0.0235). APACHE II scores and FT3 were better predictors of mortality compared to other thyroid hormones (AUC =0.8519±0.0535). FT3 showed high correlation with APACHE II score(r=-0.4083; p=0.0032). Inclusion of thyroid hormone levels with APACHE II scores improved the prediction of mortality in critically ill patients by 5.63%.Conclusion: Among thyroid hormones, FT3 is a better predictor of mortality. Use of thyroid hormone levels in conjunction with APACHE II scores improves the prognostication.

Serum thyroid hormone levels may not accurately reflect thyroid tissue levels and cardiac function in mild hypothyroidism

2008 ◽  
Vol 294 (5) ◽  
pp. H2137-H2143 ◽  
Author(s):  
Yingheng Liu ◽  
Rebecca A. Redetzke ◽  
Suleman Said ◽  
James V. Pottala ◽  
Gabriella Morreale de Escobar ◽  
...  
Keyword(s):  
Animal Model ◽  
Thyroid Hormone ◽  
Cardiac Function ◽  
Thyroid Dysfunction ◽  
Thyroid Tissue ◽  
Overt Hypothyroidism ◽  
High Dose ◽  
Hormone Levels ◽  
Cardiac Atrophy ◽  
Thyroid Hormone Levels

The link between thyroid dysfunction and cardiovascular diseases has been recognized for more than 100 years. Although overt hypothyroidism leads to impaired cardiac function and possibly heart failure, the cardiovascular consequences of borderline low thyroid function are not clear. Establishment of a suitable animal model would be helpful. In this study, we characterized a rat model to study the relationship between cardiovascular function and graded levels of thyroid activity. We used rats with surgical thyroidectomy and subcutaneous implantation of slow release pellets with three different T4 doses for 3 wk. In terminal experiments, cardiac function was evaluated by echocardiograms and hemodynamics. Myocardial arteriolar density was also quantified morphometrically. Thyroid hormone levels in serum and heart tissue were determined by RIA assays. Thyroidectomy alone led to cardiac atrophy, severe cardiac dysfunction, and a dramatic loss of arterioles. The low T4 dose normalized serum T3 and T4 levels, but cardiac tissue T3 and T4 remained below normal. Low-dose T4 failed to prevent cardiac atrophy or restore cardiac function and arteriolar density to normal values. All cardiac function parameters and myocardial arteriolar density were normalized with the middle dose of T4, whereas the high dose produced hyperthyroidism. Our results show that thyroid hormones are important regulators of cardiac function and myocardial arteriolar density. This animal model will be useful in studying the pathophysiological consequences of mild thyroid dysfunction. Results also suggest that cardiac function may provide valuable supplemental information in proper diagnosis of mild thyroid conditions.

scholarly journals Environmental Factors Affecting Thyroid-Stimulating Hormone and Thyroid Hormone Levels

2021 ◽  
Vol 22 (12) ◽  
pp. 6521
Author(s):  
Mirjana Babić Babić Leko ◽  
Ivana Gunjača ◽  
Nikolina Pleić ◽  
Tatijana Zemunik
Keyword(s):  
Thyroid Hormone ◽  
Environmental Factors ◽  
Thyroid Hormones ◽  
Thyroid Function ◽  
Lifestyle Factors ◽  
Thyroid Stimulating Hormone ◽  
Hormone Levels ◽  
Thyroid Hormone Levels ◽  
The Impact ◽  
Tsh Levels

Thyroid hormones are necessary for the normal functioning of physiological systems. Therefore, knowledge of any factor (whether genetic, environmental or intrinsic) that alters the levels of thyroid-stimulating hormone (TSH) and thyroid hormones is crucial. Genetic factors contribute up to 65% of interindividual variations in TSH and thyroid hormone levels, but many environmental factors can also affect thyroid function. This review discusses studies that have analyzed the impact of environmental factors on TSH and thyroid hormone levels in healthy adults. We included lifestyle factors (smoking, alcohol consumption, diet and exercise) and pollutants (chemicals and heavy metals). Many inconsistencies in the results have been observed between studies, making it difficult to draw a general conclusion about how a particular environmental factor influences TSH and thyroid hormone levels. However, lifestyle factors that showed the clearest association with TSH and thyroid hormones were smoking, body mass index (BMI) and iodine (micronutrient taken from the diet). Smoking mainly led to a decrease in TSH levels and an increase in triiodothyronine (T3) and thyroxine (T4) levels, while BMI levels were positively correlated with TSH and free T3 levels. Excess iodine led to an increase in TSH levels and a decrease in thyroid hormone levels. Among the pollutants analyzed, most studies observed a decrease in thyroid hormone levels after exposure to perchlorate. Future studies should continue to analyze the impact of environmental factors on thyroid function as they could contribute to understanding the complex background of gene–environment interactions underlying the pathology of thyroid diseases.

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