RESUMO
Hypothyroidism is a prevalent thyroid condition in which the thyroid gland fails to secrete an adequate amount of thyroid hormone into the bloodstream. This condition may develop due to genetic or acquired factors. The most frequent cause of acquired hypothyroidism is chronic autoimmune thyroiditis, also known as Hashimoto's disease. Acquired hypothyroidism is diagnosed when patients present with overt hypothyroidism (also known as clinical hypothyroidism), as they exhibit increased TSH and decreased T3 and T4 serum levels. This article examines the prevalence of psychiatric disorders among patients diagnosed with acquired hypothyroidism with or without Levothyroxine treatment. We discuss the available evidence indicating that acquired hypothyroidism may be a risk factor for psychiatric disorders, and the effectiveness of thyroid treatment in relieving psychiatric symptoms. Additionally, we provide critical details on thyroid hormone cutoff values reported in the literature, their potential clinical importance, and their correlation with psychiatric symptoms. Finally, we examined the various mechanisms by which acquired hypothyroidism can lead to depression. The high rate of comorbidity between hypothyroidism and psychiatric disorders deserves special attention, indicating the importance of consistent monitoring and timely identification of psychiatric symptoms to prevent disease exacerbation and facilitate therapeutic management. On the other hand, several mechanisms underlie the strong association between depression and acquired hypothyroidism. Deeper research into these mechanisms will allow knowledge of the pathophysiology of depression in patients with acquired hypothyroidism and will provide clues to design more precise therapeutic strategies for these patients.
RESUMO
The saccus vasculosus is an organ present in gnathostome fishes, located ventral to the hypothalamus and posterior to the pituitary gland, whose structure is highly variable among species. In some fishes, this organ is well-developed; however, its physiological function is still under debate. Recently, it has been proposed that this organ is a seasonal regulator of reproduction. In the present work, we examined the histology, ultrastructure, and development of the saccus vasculosus in Cichlasoma dimerus. In addition, immunohistochemical studies of proteins related to reproductive function were performed. Finally, the potential response of this organ to different photoperiods was explored. C. dimerus presented a well-developed saccus vasculosus consisting of a highly folded epithelium, composed of coronet and supporting cells, closely associated with blood vessels, and a highly branched lumen connected to the third ventricle. Coronet cells showed all the major characteristics described in other fish species. In addition, some of the vesicles of the globules were positive for thyrotropin beta subunit, while luteinizing hormone beta subunit immunostaining was observed at the edge of the apical processes of some coronet cells. Furthermore, neuropeptide Y and gonadotropin inhibitory hormone innervation in the saccus vasculosus of C. dimerus were shown. Finally, animals exposed to the long photoperiod showed lower levels of thyrotropin beta and common alpha subunits expression in the saccus compared to those of animals exposed to short photoperiod. All these results support the hypothesis that the saccus vasculosus is involved in the regulation of reproductive function in fish.
Assuntos
Ciclídeos , Fotoperíodo , Animais , Ciclídeos/anatomia & histologia , Hipófise/metabolismo , Feminino , Masculino , Imuno-Histoquímica , Reprodução/fisiologiaRESUMO
CONTEXT: The effectiveness of levothyroxine (LT4) in restoring thyroid hormone (TH) homeostasis, particularly serum thyroxine (T4) and triiodothyronine (T3) levels, remains debatable. OBJECTIVE: This work aimed to assess TH homeostasis in LT4-treated individuals using data from the Longitudinal Study of Adult Health in Brazil (ELSA-Brasil) study. METHODS: The ELSA-Brasil study follows 15 105 adult Brazilians (aged 35-74 years) over 8.2 years (2008-2019) with 3 observation points assessing health parameters including serum thyrotropin (TSH), free T4 (FT4), and free T3 (FT3) levels. We analyzed 186 participants that initiated treatment with LT4 during the study, and 243 individuals continuously treated with LT4 therapy. RESULTS: Initiation of therapy with LT4 resulted in an 11% to 19% decrease in TSH, an approximately 19% increase in FT4, and a 7% reduction in FT3 serum levels (FT3 dropped >10% in â¼40% of the LT4-treated patients). This was associated with an increase in triglyceride levels and utilization of hypolipidemic and antidiabetic medications. Participants continuously treated with LT4 exhibited a stable elevation in serum FT4 and a reduction in serum FT3 and TSH levels. While 115 participants (47.3%) had at least 1 serum FT4 levels above the control reference range (>1.52â ng/dL), 38 participants (15.6%) had at least 1 serum FT3 below the reference range (<0.23â ng/dL). CONCLUSION: The present results challenge the dogma that treatment with LT4 for hypothyroidism restores TH homeostasis in all patients. A substantial number of LT4-treated patients exhibit repeated FT4 and FT3 levels outside the normal reference range, despite normal TSH levels. Further studies are needed to define the clinical implications of these findings.
Assuntos
Homeostase , Hipotireoidismo , Tiroxina , Humanos , Pessoa de Meia-Idade , Tiroxina/uso terapêutico , Tiroxina/sangue , Tiroxina/administração & dosagem , Feminino , Masculino , Adulto , Homeostase/efeitos dos fármacos , Hipotireoidismo/tratamento farmacológico , Hipotireoidismo/sangue , Estudos Longitudinais , Idoso , Brasil , Hormônios Tireóideos/sangue , Tri-Iodotironina/sangue , Tireotropina/sangue , Testes de Função Tireóidea , Terapia de Reposição Hormonal/métodosRESUMO
Thyroid hormone has been shown to have both tumor-promoting and tumor-suppressing actions, which has led to significant debate over its involvement in the development of cancer. Proliferation, apoptosis, invasiveness, and angiogenesis are all aspects of cancer that are affected by the thyroid hormones T3 and T4, according to research conducted in animal models and in vitro experiments. The effects of thyroid hormones on cancer cells are mediated by many non-genomic mechanisms, one of which involves the activation of the plasma membrane receptor integrin αvß3. Typically, abnormal amounts of thyroid hormones are linked to a higher occurrence of cancer. Both benign and malignant thyroid disorders were found to be associated with an increased risk of extra-thyroidal malignancies, specifically colon, breast, prostate, melanoma, and lung cancers. The purpose of this review was to shed light on this link to define which types of cancer are sensitive to thyroid hormones and, as a result, are anticipated to respond favorably to treatment of the thyroid hormone axis.
Assuntos
Neoplasias , Doenças da Glândula Tireoide , Doenças da Glândula Tireoide/complicações , Neoplasias/complicações , Neoplasias/patologia , Neoplasias/terapia , Hormônios Tireóideos/metabolismo , Progressão da Doença , HumanosRESUMO
Central hypothyroidism (CH) is characterized by decreased thyroid hormone production due to insufficient stimulation of an otherwise normal thyroid gland by TSH. In patients with established hypothalamic-pituitary disease, a low FT4 concentration is considered highly specific, although poorly sensitive, for the diagnosis of CH. That would be comparable to diagnosing primary hypothyroidism in patients at risk only when serum FT4 concentrations are below the reference range, missing all patients with subclinical primary hypothyroidism and preventing proper therapy in patients in which thyroxine replacement is clearly beneficial. Cardiac time intervals, especially the isovolumic contraction time (ICT), have been considered the gold standard of peripheral thyroid hormone action. Using Doppler echocardiography, we have previously shown a very high proportion of prolonged ICT in patients with hypothalamic-pituitary disease and serum FT4 levels indistinguishable from controls. As ICT decreased/normalized after thyroxine-induced increases in FT4 concentrations within the normal reference range, prolonged ICT was considered a bona fide diagnostic biomarker of subclinical CH. Those findings challenge the usual interpretation that FT4 concentrations in the mid-reference range exclude hypothyroidism in patients with hypothalamic-pituitary disease. Rather, subclinical central hypothyroidism, a state analogous to subclinical primary hypothyroidism, seems to be frequent in patients with hypothalamic-pituitary disease and normal FT4 levels. They also challenge the notion that thyroid function is usually the least or the last affected in acquired hypopituitarism. The relevance of Doppler echocardiography to correctly diagnose and monitor replacement therapy in both clinical and subclinical forms of CH should improve quality of life and decrease cardiovascular risk, as already demonstrated in patients with clinical and subclinical primary hypothyroidism.
Assuntos
Doenças Hipotalâmicas , Hipotireoidismo , Humanos , Doenças Hipotalâmicas/diagnóstico , Doenças da Hipófise/diagnóstico , Tiroxina/uso terapêutico , Tiroxina/sangueRESUMO
OBJECTIVE: To determine among infants born very preterm (VPT) or with very low birth weight (VLBW) the incidence of alterations in thyroid function and associated comorbidities; the incidence of atypical congenital hypothyroidism (CH) requiring thyroxine therapy; and reference ranges for rescreening at 1 month of age. STUDY DESIGN: A retrospective review of infants born VPT or with VLBW and admitted to UC Irvine Medical Center between January 1, 2012, and December 31, 2020. Repeat thyroid screening was obtained at 1 month of life (+10 days). Infants with thyroid-stimulating hormone (TSH) >5 µIU/mL or free thyroxine <0.8 ng/dL underwent follow-up testing and endocrinology consultation. Initial newborn screening (NBS) and repeat thyroid screening data were collected via chart review. Demographic data and short-term outcomes were abstracted from the California Perinatal Quality Care Collaborative database. RESULTS: In total, 430 patients were included; 64 of 429 patients (14.9%) had TSH >5 µIU/mL and 20 of 421 patients (4.8%) had free thyroxine <0.8 ng/dL. Logistic regression analysis identified small for gestational age (P = .044), patent ductus arteriosus (P = .013), and late-onset sepsis (P = .026) as risk factors associated with delayed TSH rise. Atypical CH requiring treatment through neonatal intensive care unit discharge was diagnosed in 6 patients (incidence of 1.4%); none were identified by NBS. The 90th percentile TSH for infants with extremely low birth weight (<1000 g) was 7.2 µIU/mL, and the 95th percentile for those with birth weight of 1000-1500 g was 6.1 µIU/mL; using these cutoff values identified all infants diagnosed with atypical CH with 100% sensitivity and 90%-95% specificity. CONCLUSIONS: Abnormal thyroid function is common in infants born preterm. Those infants, including some with atypical CH, are missed by NBS. We recommend repeat thyroid screening with TSH at 1 month of age in infants born VPT or infants with VLBW to identify CH that may require therapy.
Assuntos
Hipotireoidismo Congênito , Recém-Nascido de muito Baixo Peso , Triagem Neonatal , Tireotropina , Humanos , Recém-Nascido , Estudos Retrospectivos , Hipotireoidismo Congênito/diagnóstico , Hipotireoidismo Congênito/sangue , Hipotireoidismo Congênito/epidemiologia , Masculino , Feminino , Triagem Neonatal/métodos , Tireotropina/sangue , Tiroxina/sangue , Tiroxina/uso terapêutico , Lactente Extremamente Prematuro , Doenças do Prematuro/diagnóstico , Doenças do Prematuro/sangue , Doenças do Prematuro/epidemiologia , Testes de Função Tireóidea , IncidênciaRESUMO
Background: Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus known to cause two major diseases: adult T-cell leukemia/lymphoma and a progressive neuromyelopathy-tropical spastic paraparesis. Many viruses may be involved in the pathogenesis of thyroiditis; however, few studies have focused on the role of HTLV-1. We aimed to investigate the association between HTLV-1 and biological thyroid dysfunction. Methods: We included 357 patients with a positive HTLV-1 serology and thyroid-stimulating hormone assay data between 2012 and 2021 in a hospital in French Guiana; we compared the prevalence of hypothyroidism and hyperthyroidism in this group with that in an HTLV-1-negative control group (722 persons) matched for sex and age. Results: The prevalence of hypothyroidism and hyperthyroidism in patients with HTLV-1 infection was significantly higher than that in the control group (11% versus 3.2% and 11.3% versus 2.3%, respectively; p < 0.001). Conclusion: Our study shows, for the first time, the association between HTLV-1 and dysthyroidism in a large sample, suggesting that thyroid function exploration should be systematically implemented in this population as this may have an impact on therapeutic management.
Assuntos
Vírus Linfotrópico T Tipo 1 Humano , Hipertireoidismo , Hipotireoidismo , Leucemia-Linfoma de Células T do Adulto , Adulto , Humanos , Hipertireoidismo/complicações , Hipertireoidismo/epidemiologia , Hipertireoidismo/virologia , Hipotireoidismo/complicações , Hipotireoidismo/epidemiologia , Hipotireoidismo/virologia , Leucemia-Linfoma de Células T do Adulto/complicações , Leucemia-Linfoma de Células T do Adulto/epidemiologia , Masculino , Feminino , Adolescente , Adulto Jovem , Pessoa de Meia-Idade , Idoso , Estudos de Casos e Controles , Guiana Francesa/epidemiologia , PrevalênciaRESUMO
BACKGROUND: The population prevalence of functional alterations and thyroid autoimmunity is high, and numerous genetic and environmental aspects have been described as triggering factors. OBJECTIVES: The objective of this study was to determine the prevalence of functional alterations and thyroid autoimmunity in an urban population of Colombia. MATERIALS AND METHODS: It is a cross-sectional, population-based study (n = 9,638) conducted on an urban population of Popayán-Cauca-Colombia between February 5th, 2018, to December 11th, 2021. The variables evaluated were thyrotropin (TSH), free T4 (FT4), and anti-thyroid antibodies (thyroid peroxidase antibodies: TPOAb, and thyroglobulin antibodies: TgAb). RESULTS: TSH in men was significantly higher than in women. No differences were observed in the values of FT4, TPOAb, and TgAb (according to sex). The prevalence of normal thyroid function and subclinical hypothyroidism was significantly higher in men. The positivity of TPOAb and TgAb was 22.3% and 19.2%, respectively. TSH levels increased with age (both in men and in women). In participants with normal FT4 and negative TPOAb, the TSH was significantly higher. TSH was significantly higher in TPOAb-positive individuals and among those with TPOAb and TgAb positives, as well as in women with positive TPOAb and men with positive TPOAb and TgAb. CONCLUSION: In an urban population of Colombia, TSH was found to be higher than in populations of other geographical areas, especially in older individuals and in the presence of positive anti-thyroid antibodies, a high prevalence of functional alterations and thyroid autoimmunity was also found. These findings can be explained by excess iodine consumption and some environmental factors.
Assuntos
Autoanticorpos , Autoimunidade , Masculino , Humanos , Feminino , Idoso , População Urbana , Prevalência , Estudos Transversais , Colômbia/epidemiologia , TireotropinaRESUMO
A exposição ou secreção de proteínas relacionadas a fatores de virulência de bactérias Gram-negativas é dependente de sistemas de transporte altamente especializados. O sistema de secreção tipo V é o responsável pelo transporte das proteínas autotransportadoras membros da família das Serino-Proteases Autotransportadoras de Enterobacteriaceae (SPATE), as quais diversas funções de virulência vêm sendo atribuídas. SPATEs têm sido descritas em bactérias isoladas de infecções gastrointestinais, trato urinário, meningite e sepse. O objetivo deste trabalho foi contribuir com os estudos de caracterização do papel das toxinas da família das serino-proteases autotransportadoras de Enterobacteriaceae Vat, Tsh e Sat na infecção bacteriana avaliando, particularmente, a funcionalidade da Tsh purificada por gel filtração. Inicialmente a cinética de crescimento de E. coli patogênicas das cepas EC120 vat+ ou EC077, EC046, EC153 e EC143 tsh+ foi realizada nos meios TSB, LB, DMEM e DMEM acrescido de 1% de triptona a fim de determinar o melhor meio e tempo de cultivo que favorece a secreção das proteínas autotransportadoras. Para a obtenção da Tsh, a cepa EC143 foi cultivada em meio LB. O sobrenadante do cultivo concentrado foi submetido à coluna de gel filtração e as frações foram analisadas por SDS-PAGE e Westen Blotting. A quantidade de proteína das frações contendo Tsh foi determinada e a avaliação da funcionalidade da toxina foi realizada pelo ensaio de hemaglutinação de eritrócitos de galinha, clássico para avaliar a atividade de Tsh. Paralelamente, Vat e Sat foram também submetidas à hemaglutinação. Os resultados mostraram que a funcionalidade da Tsh purificada por gel filtração é mantida, que Vat não tem capacidade hemaglutinante e que a determinação da capacidade hemaglutinante de Sat necessita de maiores estudos visto que em presença de PMSF (inibidor de serino protease) o resultado foi mantido. Como o PMSF pode estar danificando os eritrócitos, novos ensaios utilizando, por exemplo, anticorpos anti-Sat para neutralizar o efeito serão realizados.
RESUMO
Background: The influence of thyroid-stimulating hormone (TSH) on gestational outcomes have been studied and checked whether differing TSH levels are relevant on human reproduction outcomes. International guidelines recommend TSH values <2.5 mIU/L in women trying to conceive, since values above this level are related to a higher frequency of adverse reproductive outcomes. This study aimed to evaluate whether TSH values correlate with different gestational outcomes in euthyroid infertile women without autoimmune thyroid disease. Methods: A retrospective cohort study was conducted involving 256 women who underwent in vitro fertilization (IVF) treatment. The participants were divided into two groups: TSH 0.5-2.49 mIU/L (n=211) and TSH 2.5-4.5 mIU/L (n=45). The clinical data, hormonal profiles and reproductive outcomes were compared between groups. Additionally, a systematic review with meta-analysis following the PRISMA protocol was carried out in PubMed/MEDLINE, EMBASE, and SciELO, with no time or language restrictions, for articles comparing TSH groups named "low TSH" (<2,5 mIU/L) and "high TSH" (≥2.5 mIU/L). A meta-analysis of proportions was performed with pooled estimates expressed as relative risk (RR) of events and a random effects model. Results: Age, BMI, free thyroxine levels (FT4) hormonal profile and IVF outcomes were not different between groups, neither gestational outcomes (p=0.982). Also, no difference was observed when the TSH and FT4 levels were compared between patients with positive or negative gestational outcomes (p=0.27 and p=0.376). Regarding the systematic review with meta-analysis, 17 studies from 2006 to 2022 were included, and added by this original retrospective research comprising 13.247 women undergoing IVF. When comparing the proportions of clinical pregnancy between the TSH groups, no significant difference was found (RR 0.93, 95% CI 0.80-1.08), with high between studies heterogeneity (I²: 87%; τ2: 0.0544; p<0.01). The number of deliveries was not significantly different between groups, despite a trend towards higher frequency in the high-TSH group (RR 0.96, 95% CI 0.90-1.02). Conclusion: Variation in TSH levels within the normal range was not associated with pregnancy and delivery rates in women, without autoimmune thyroid disease, who underwent IVF treatment. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD 42022306967.