Thyroid Function in Human Obesity: Underlying Mechanisms

Fontenelle, Larissa Cristina; Feitosa, Mayara Monte; Silva, Juliana; Freitas, Taynáh Emannuelle Coelho de; Morais, Jennifer Beatriz Silva; Leal, Francisco; Henriques, Gilberto Simeone; Marreiro, Dilina do Nascimento

doi:10.1055/s-0042-121421

Cited by 102 publications

(115 citation statements)

References 72 publications

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“…Since these situations bear a resemblance to classical type 2 allostatic load, we will sum them up as type 2 thyroid allostasis . This is further justified because a high-T3 constellation in the absence of hyperthyroidism is also observed in obesity (111) and psychosocial stress (112), i.e., type 2 allostatic load according to the classic definition by McEwen and Wingfield.…”

Section: Mechanisms Of Thyroid Allostasismentioning

confidence: 99%

“…It is linked to multiple metabolic and endocrine responses (111) including thyroid function. The interconnection between thyroid hormones and body weight is bidirectional, and both hypothyroidism and hyperthyroidism are known to result in changes of body mass.…”

Section: Thyroid Allostasis In Various Physiological and Pathologicalmentioning

confidence: 99%

“…The interconnection between thyroid hormones and body weight is bidirectional, and both hypothyroidism and hyperthyroidism are known to result in changes of body mass. Conversely, obesity may result in adaptive responses of thyroid homeostasis: a variety of studies, as recently reviewed by Pacifico et al (195) and Fontenelle et al (111), described elevated TSH levels and increased total step-up deiodinase activity (although predominantly within the reference range) in patients with weight gain, while concentration of rT3 has been reported to be decreased. Reversibility of these alterations after weight loss indicates that they are consequence rather than cause of overweight (196).…”

Section: Thyroid Allostasis In Various Physiological and Pathologicalmentioning

confidence: 99%

“…Both central and peripheral components of the feedback loop are apparently involved in the reactive adjustments to obesity (Figure 7). Increased concentrations of adipokines such as leptin have been proposed to be a key element of obesity-related thyroid allostasis, but mitochondrial dysfunction (195, 198), chronic inflammation, and insulin resistance (199) as well as both central and peripheral resistance to thyroid hormone may play additional roles (111). …”

Section: Thyroid Allostasis In Various Physiological and Pathologicalmentioning

confidence: 99%

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Thyroid Allostasis–Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming

Hoermann²,

et al. 2017

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The hypothalamus–pituitary–thyroid feedback control is a dynamic, adaptive system. In situations of illness and deprivation of energy representing type 1 allostasis, the stress response operates to alter both its set point and peripheral transfer parameters. In contrast, type 2 allostatic load, typically effective in psychosocial stress, pregnancy, metabolic syndrome, and adaptation to cold, produces a nearly opposite phenotype of predictive plasticity. The non-thyroidal illness syndrome (NTIS) or thyroid allostasis in critical illness, tumors, uremia, and starvation (TACITUS), commonly observed in hospitalized patients, displays a historically well-studied pattern of allostatic thyroid response. This is characterized by decreased total and free thyroid hormone concentrations and varying levels of thyroid-stimulating hormone (TSH) ranging from decreased (in severe cases) to normal or even elevated (mainly in the recovery phase) TSH concentrations. An acute versus chronic stage (wasting syndrome) of TACITUS can be discerned. The two types differ in molecular mechanisms and prognosis. The acute adaptation of thyroid hormone metabolism to critical illness may prove beneficial to the organism, whereas the far more complex molecular alterations associated with chronic illness frequently lead to allostatic overload. The latter is associated with poor outcome, independently of the underlying disease. Adaptive responses of thyroid homeostasis extend to alterations in thyroid hormone concentrations during fetal life, periods of weight gain or loss, thermoregulation, physical exercise, and psychiatric diseases. The various forms of thyroid allostasis pose serious problems in differential diagnosis of thyroid disease. This review article provides an overview of physiological mechanisms as well as major diagnostic and therapeutic implications of thyroid allostasis under a variety of developmental and straining conditions.

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Section: Mechanisms Of Thyroid Allostasismentioning

confidence: 99%

Section: Thyroid Allostasis In Various Physiological and Pathologicalmentioning

confidence: 99%

Section: Thyroid Allostasis In Various Physiological and Pathologicalmentioning

confidence: 99%

Section: Thyroid Allostasis In Various Physiological and Pathologicalmentioning

confidence: 99%

See 2 more Smart Citations

Thyroid Allostasis–Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming

Hoermann²,

et al. 2017

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“…The inflammatory adipokines may also alter the activity of deiodinases. The decrease in these adipokines together with the body fat ratio causes a decrease in thyroid function (16).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of changes in vitamin B12, ferritin, folic acid, and thyroid hormone levels after sleeve gastrectomy

Doğan¹,

Oruç²

2017

J Turgut Ozal Med Cent

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Aim: The aim of this study was to evaluate the changes in vitamin B12, ferritin, folic acid, and thyroid hormone levels in patients with morbid obesity after laparoscopic sleeve gastrectomy (LSG). Material and Methods: A total of 85 patients who underwent LSG operation with the diagnosis of morbid obesity were included in the study. Levels of vitamin B12, ferritin, folic acid, and thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) hormone were measured using the chemiluminescence method. Pre-and postoperative levels of thyroid hormones, vitamin B12, ferritin, folic acid, and BMI values were evaluated. Results: The mean BMI decreased from 45.44 ± 3.8 kg/m2 to 39.38 ± 3.69 kg/m2 (p<0.001). The mean TSH, fT3, vitamin B12, folic acid, and ferritin levels were statistically significant lower at six months postoperatively than preoperative levels, while the mean fT4 levels were found to be significantly higher (p<0.001). Preoperative and 6thmonth postoperative ferritin levels were significantly lower in female patients than male patients (p<0.001). There was a negative correlation between age with preoperative TSH and fT3 levels. There was a positive correlation between age and preoperative and 6thmonth postoperative folic acid levels. Conclusion: Remodeling of the gastrointestinal system and endocrine alterations after LSG may result in changes in the levels of nutritional parameters such as thyroid hormone, vitamin B12, folic acid, and ferritin. Therefore, based on our study findings, we consider that the nutritional status of patients after bariatric surgery should be monitored particularly in long-term and nutritionally supported, if necessary.

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Oxidized Pork Induces Hepatic Steatosis by Impairing Thyroid Hormone Function in Mice

Yang

Jiang

et al. 2021

Molecular Nutrition Food Res

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Scope: Recent studies have linked high consumption of red and processed meats to an increased risk of non-alcoholic fatty liver disease, and cooking-induced oxidation of proteins and amino acids might be contributing factors. Herein, this study investigates the influence of oxidized pork and the protein oxidation biomarker dityrosine (Dityr) on hepatic steatosis in mice. Methods and Results: Low-and high-oxidative injury pork (LOP and HOP) are freeze-dried to prepare mouse diets. Mice are fed a diet of either the control, LOP, HOP, LOP+Dityr, or Dityr for 12 weeks. HOP and Dityr intake induced oxidative stress and inflammation that impaired thyroid function and peripheral metabolism (reduced type 1 deiodinase activity) of thyroid hormones (THs). These lead to a decrease in the circulating as well as liver THs and induced hepatic steatosis. This process might be regulated through reduced TH levels and altered TH target genes and proteins related to hepatic lipid metabolism that ultimately inhibited hepatic energy metabolism, as indicated by increased hepatic lipid synthesis, decreased hepatic lipid catabolism, and fatty acid oxidation. Conclusion: HOP intake could induce hepatic steatosis by impairing TH function. Dityr plays an important role in the HOP-induced harmful effects.

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Thyroid Function in Human Obesity: Underlying Mechanisms

Cited by 102 publications

References 72 publications

Thyroid Allostasis–Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming

Thyroid Allostasis–Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming

Evaluation of changes in vitamin B12, ferritin, folic acid, and thyroid hormone levels after sleeve gastrectomy

Oxidized Pork Induces Hepatic Steatosis by Impairing Thyroid Hormone Function in Mice

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