Effects of acute hypothyroidism on plasma melatonin and Aanat and Asmt expression in the pineal gland and gonads of rats.

Introduction: The reproductive system is tightly regulated by environmental and physiological signals. Melatonin, known as the hormone of darkness, plays a crucial role in regulating both the circadian and reproductive systems in mammals. Hypothyroidism is a key endocrine disorder that harms the reproductive system. Despite many studies on melatonin's effects on the reproductive system, there is conflicting information regarding melatonin synthesis modulation in hypothyroidism. The objective of this study was to investigate the modulation of plasma melatonin levels and gene expression of Aanat and Asmt in the pineal gland and gonads of rats with hypothyroidism at different times of the day. Methods: Female and male Wistar rats were divided into control and hypothyroid groups. Hypothyroidism was induced using propylthiouracil (PTU) for 15 days, rats were euthanized six hours after lights on (ZT6), before lights off (ZT11.5), and six hours after lights off (ZT18). Free thyroxine (FT4) and melatonin were quantified in plasma, and gene expressions of melatonin synthesizing enzymes (Aanat and Asmt) were measured in pineal and sexual organs (testis and ovary). Also, morphological analysis was performed in sexual organs. Results: The results reveal some disparities between the sexes. Hypothyroidism reduced antral and primary follicles in the ovary, and reduced the weight of testis, epididymis, and prostate. In relation to gene expression, we observed a reduction in Aanat expression in the pineal gland during the light phase (ZT6), and in males, this reduction occurred during the dark phase (ZT18). Regarding Asmt expression, there was a decrease in females also during the dark phase (ZT18). In the gonads, there was an increase in expression in both sexes at ZT11.5. Additionally, it was interesting to observe the association between FT4 levels and Asmt expression in the gonads. Conclusions: This study showed that acute hypothyroidism can affect components of the melatonergic system in gonads, particularly gene expression of melatonin synthesis enzymes (Aanat and Asmt) contributing to changes in reproduction organs during disease progression. These findings enhance our understanding of melatonin synthesis in the reproductive system during hypothyroidism, showing distinct responses in male and female rats, and suggest that hypothyroidism affects the circadian rhythmicity of melatonin synthesis in a sex-dependent manner.

[Leukocytoclastic vasculitis as an adverse effect of propylthiouracil. A case report]. / Vasculitis leucocitoclástica como efecto adverso del propiltiouracilo. Reporte de un caso.

BACKGROUND: The most common cause of hyperthyroidism is Graves' disease. Propylthiouracil (PTU) is one of the drugs used to treat this disease. Leukocytoclastic vasculitis is described among dermatologic adverse effects of PTU. CASE REPORT: A 18-year-old woman, allergic to methimazole, developed a vasculitis associated to ANCAs with characteristics of leukocytoclastic vasculitis, associated to PTU treatment. She did not present systemic involvement. PTU treatment was suspended. Two months later, the skin lesions had almost completely resolved. CONCLUSIONS: Leukocytoclastic vasculitis should be considered in the spectrum of complications caused by the consumption of propylthiouracil. The lesions can manifest over time, from a few weeks to years after taking the drug. When there is no systemic involvement, propylthiouracil suspension is sufficient to cure the disease.

ANTECEDENTES: La causa más frecuente de hipertiroidismo es la enfermedad de Graves. El propiltiouracilo es uno de los medicamentos más prescritos para esta enfermedad. Uno de los efectos adversos dermatológicos del propiltiouracilo es la vasculitis leucocitoclástica. REPORTE DE CASO: Paciente femenina de 18 años, alérgica al metamizol, con vasculitis asociada a ANCAs, con características de vasculitis leucocitoclástica provocada por el consumo de propiltiouracilo. No se observó afectación sistémica. Dos meses después de suspender el propiltiouracilo desaparecieron casi por completo las lesiones en la piel. CONCLUSIONES: La vasculitis leucocitoclástica debe considerarse en el espectro de complicaciones provocadas por el consumo de propiltiouracilo. Las lesiones pueden manifestarse con el paso del tiempo, desde unas semanas hasta años después de consumir el fármaco. Cuando no existe afectación sistémica, la suspensión del propiltiouracilo es suficiente para detener la enfermedad.

Maternal hypothyroidism causes oxidative stress and endoplasmic reticulum stress in the maternal-fetal interface of rats.

Maternal hypothyroidism is associated with pre-eclampsia and intrauterine growth restriction, gestational diseases involving oxidative stress (OS) and endoplasmic reticulum stress (ERS) in the placenta. However, it is not known whether hypothyroidism also causes OS and ERS at the maternal-fetal interface. The aim was to evaluate the fetal-placental development and the expression of mediators of OS and of the unfolded protein response (UPR) in the maternal-fetal interface of hypothyroid rats. Hypothyroidism was induced in Wistar rats with propylthiouracil and the fetal-placental development and placental and decidual expression of antioxidant, hypoxia, and UPR mediators were analyzed at 14 and 18 days of gestation (DG), as well the expression of 8-OHdG and MDA, and reactive oxygen species (ROS) and peroxynitrite levels. Hypothyroidism reduced fetal weight at 14 and 18 DG, in addition to increasing the percentage of fetal death and reducing the weight of the uteroplacental unit at 18 DG. At 14 DG, there was greater decidual and/or placental immunostaining of Hif1α, 8-OHdG, MDA, SOD1, GPx1/2, Grp78 and CHOP in hypothyroid rats, while there was a reduction in placental and/or decidual gene expression of Sod1, Gpx1, Atf6, Perk, Ho1, Xbp1, Grp78 and Chop in the same gestational period. At 18 DG, hypothyroidism increased the placental ROS levels and the decidual and/or placental immunostaining of HIF1α, 8-OHdG, MDA, ATF4, GRP78 and CHOP, while it reduced the immunostaining and enzymatic activity of SOD1, CAT, GST. Hypothyroidism increased the placental mRNA expression of Hifα, Nrf2, Sod2, Gpx1, Cat, Perk, Atf6 and Chop at 18 DG, while decreasing the decidual expression of Sod2, Cat and Atf6. These findings demonstrated that fetal-placental restriction in female rats with hypothyroidism is associated with hypoxia and dysregulation in placental and decidual expression of UPR mediators and antioxidant enzymes, and activation of oxidative stress and endoplasmic reticulum stress at the maternal-fetal interface.

Cooked common bean flour, but not its protein hydrolysate, has the potential to improve gut microbiota composition and function in BALB/c mice fed a high-fat diet added with 6-propyl-2-thiouracil.

Common bean has the potential to improve gut microbiota function due to its chemical composition and content of dietary fiber. This study evaluated the effect of cooked common bean (CCB) flour and its protein hydrolysate as part of a high-fat diet (HFD) added with 6-propyl-2-thiouracil (10 mg/kg/d), an inhibitor of thyroid hormone synthesis, on gut health of BALB/c mice. Forty-eight adult mice were divided into four groups: normal control; HFD; HFD plus CCB flour (346.6 g/kg of diet) (HFBF group) and HFD plus CCB protein hydrolysate (700 mg/Kg/d) (HFPH group). HFBF, but not HFPH, increased cecum weight, and the moisture, and lipids in the excreted feces, compared to control groups. Sequencing of the 16S rRNA gene of the cecal microbiota indicated changes in the beta-diversity between the HFBF and HFPH groups, compared to the normal control. The abundance of Bacteroidetes increased and the Firmicutes/Bacteroidetes ratio decreased in the HFBF compared to control groups. However, HFPH was not able to prevent the damage caused by a HFD to the gut bacterial communities. The OTUs enriched by HFBF were mainly assigned to members of the Muribaculaceae family, which shows potential to improve gut health. The intake of CCB flour improved intestinal health and modulated the composition and function of the cecal microbiota, attenuating the effects of the HFD, added wit 6-propyl-2-thiouracil, when fed to BALB/c mice.

Effects of thyroxine on apoptosis and proliferation of mammary tumors.

Hypothyroidism is a protective factor against breast cancer but long-term exposure or overdoses of thyroid replacement therapy with thyroxine (T4) may increase breast cancer risk. OBJECTIVE: to study, in vivo and in vitro, the effects of T4 on the proliferation and apoptosis of mammary tumors of hypo- and euthyroid rats, and the possible mechanisms involved in these effects. MATERIAL AND METHODS: Female Sprague-Dawley rats were treated with a single dose of dimethylbenzathracene (15 mg/rat) at 55 days of age and were divided into three groups: hypothyroidism (HypoT; 0.01% 6-N-propyl-2-thiouracil -PTU- in drinking water, n = 20), hypothyroidism treated with T4 (HypoT + T4; 0.01% PTU in drinking water and 0.25 mg/kg/day T4 via sc; n = 20) and EUT (untreated control, n = 20). At sacrifice, tumor explants from HypoT and EUT rats were obtained and treated either with 10-10 M T4 in DMEM/F12 without phenol red with 1% Charcoalized Fetal Bovine Serum or DMEM/F12 only for 15 min to evaluate intracellular signaling pathways associated with T4, and 24 h to evaluate changes in the expression of hormone receptors and proteins related to apoptosis and proliferation by immunohistochemistry and Western Blot. RESULTS: In vivo, hypothyroidism retards mammary carcinogenesis but its treatment with T4 reverted the protective effects. In vitro, the proliferative and anti-apoptosis mechanisms of T4 were different regarding the thyroid status. In EUT tumors, the main signaling pathway involved was the cross-talk with other receptors, such as ERα, PgR, and HER2. In HypoT tumors, the non-genomic signaling pathway of T4 was the chief mechanism involved since αvß3 integrin, HER2, ß-catenin and, downstream, PI3K/AKT and ERK signaling pathways were activated. CONCLUSION: T4 can regulate mammary carcinogenesis by mainly activating its non-genomic signaling pathway and by interacting with other hormone or growth factor pathways endorsing that overdoses of thyroid replacement therapy with T4 can increase the risk of breast cancer.

Adhesion molecules before and after propylthiouracil in patients with subclinical hyperthyroidism.

OBJECTIVE: This study aimed to investigate the effect of propylthiouracil treatment on adhesion molecules in patients with subclinical hyperthyroidism. METHODS: In this study, a total of 168 patients diagnosed with subclinical hyperthyroidism were treated with propylthiouracil for one year. The levels of adhesion molecules, consisting of sICAM-1, sVCAM-1, and sE-Selectin, before and after the treatment were measured and compared. These results were compared with the levels of 148 healthy controls who received a placebo. RESULTS: sICAM-1 levels were significantly higher in subclinical hyperthyroidism patients than in healthy controls (*pa=0.000). sICAM-1 levels were significantly decreased after the treatment (**pb=0.000). Despite this decrease in patients with subclinical hyperthyroidism, it did not decrease to the level of the control group. sVCAM-1 did not change before and after propylthiouracil treatment. The level of sE-selectin was similar to that of the pretreatment control group, but it did not have statistical significance, although it increased after the treatment (**pb=0.004). CONCLUSION: The sICAM level was significantly higher than the pretreatment values and decreased after the propylthiouracil treatment. However, further studies are needed to reduce the risk of atherosclerosis and cancer in patients with subclinical hyperthyroidism.

Hypothyroidism induced by postnatal PTU (6-n-propyl-2-thiouracil) treatment decreases Sertoli cell number and spermatogenic efficiency in sexually mature pigs.

Studies with 6-n-propyl-2-thiouracil (PTU) in laboratory rodents have shown that transient neonatal hypothyroidism leads to increased Sertoli cell (SC) number, testis size and sperm production. However, scarce and inconclusive data are available for farm animals. In the present study, Piau pigs received PTU in a gel capsule containing 8 mg/kg of body weight for 14 weeks starting from the first week of age, whereas control animals received only the vehicle. Blood samples were collected during the experimental period for hormonal evaluation in the serum. The animals were orchiectomized at adulthood and had their testes used for histomorphometric analysis. Indicating that the PTU concentration used was effective in promoting hypothyroidism, PTU-treated pigs showed a 30% lower body weight and reduced thyroxine levels (p < 0.05) during the treatment period. At adulthood, the body weight was similar in both groups but, surprisingly, PTU-treated pigs showed 30% lower testis weight (p < 0.05). In general, treated pigs presented increased follicle-stimulating hormone levels, whereas testosterone levels tended to be lower from 9 to 23 weeks of age. No significant differences were observed for estradiol, Leydig cell volume and number, tubular diameter, SC number per gram of testis, SC efficiency and meiotic index. However, seminiferous tubule occupancy, total tubular length, SC number per testis, and daily sperm production per testis and per gram of testis (DSP/g/T) were significantly lower (p < 0.05) in PTU-treated pigs. Therefore, in contrast to laboratory rodents, our results showed that SC proliferation and DSP/g/T (spermatogenic efficiency) in Piau pigs is diminished by postnatal PTU treatment.

Adhesion molecules before and after propylthiouracil in patients with subclinical hyperthyroidism

SUMMARY OBJECTIVE This study aimed to investigate the effect of propylthiouracil treatment on adhesion molecules in patients with subclinical hyperthyroidism. METHODS In this study, a total of 168 patients diagnosed with subclinical hyperthyroidism were treated with propylthiouracil for one year. The levels of adhesion molecules, consisting of sICAM-1, sVCAM-1, and sE-Selectin, before and after the treatment were measured and compared. These results were compared with the levels of 148 healthy controls who received a placebo. RESULTS sICAM-1 levels were significantly higher in subclinical hyperthyroidism patients than in healthy controls (*pa=0.000). sICAM-1 levels were significantly decreased after the treatment (**pb=0.000). Despite this decrease in patients with subclinical hyperthyroidism, it did not decrease to the level of the control group. sVCAM-1 did not change before and after propylthiouracil treatment. The level of sE-selectin was similar to that of the pretreatment control group, but it did not have statistical significance, although it increased after the treatment (**pb=0.004). CONCLUSION The sICAM level was significantly higher than the pretreatment values and decreased after the propylthiouracil treatment. However, further studies are needed to reduce the risk of atherosclerosis and cancer in patients with subclinical hyperthyroidism.

RESUMO ANTECEDENTES O objetivo deste estudo foi investigar o efeito do tratamento com propiltiouracil nas moléculas de adesão em pacientes com hipertireoidismo subclínico. MÉTODOS Neste estudo, 168 pacientes diagnosticados com hipertireoidismo subclínico foram tratados com propiltiouracil por um ano. Os níveis de moléculas de adesão, especificamente sICAM-1, sVCAM-1 e sE-Selectina, antes e após o tratamento foram medidos e comparados. Esses resultados foram comparados com os níveis de 148 indivíduos saudáveis no grupo de controle que receberam um placebo. RESULTADOS Os níveis de sICAM-1 foram significativamente maiores em pacientes com hipertireoidismo subclínico do que nos controles saudáveis (*pa=0,000). Os níveis de sICAM-1 diminuíram significativamente após o tratamento (**pb=0,000). Apesar dessa diminuição em pacientes com hipertireoidismo subclínico, ela não diminuiu para o nível do grupo controle. O sVCAM-1 não se alterou antes e após o tratamento com propiltiouracil. O nível de sE-Selectina foi semelhante ao do grupo de controle pré-tratamento, mas não apresentou significância estatística, embora tenha aumentado após o tratamento (** pb = 0,004). CONCLUSÃO O nível de sICAM foi significativamente superior aos valores pré-tratamento e diminuiu após o tratamento com propilciliouracil. No entanto, mais estudos são necessários para reduzir o risco de aterosclerose e câncer em pacientes com hipertireoidismo subclínico.

Presentación de un caso de agranulocitosis por propiltiouracilo / Presentation of a case of agranulocytosis caused by propylthiouracil

Se estudió una paciente de 33 años de edad con antecedentes patológicos de Bocio tiroideo difuso desde hace 8 años, que acude al cuerpo de guardia por presentar falta de aire, fiebre de 39-40 °C, dolor de garganta y palpitaciones hace alrededor de tres días. Al examen físico se le constató exoftalmos, mucosas hipocoloreadas y faringe purulenta y punteada de color blanquecina, artralgia y taquicardia. Referente a los exámenes complementarios presentó anemia, leucopenia y pancitopenia luego de haber consumido propiltiouracilo (50mg) por un período prolongado; por lo que se concluye como agranulocitosis como consecuencia de una reacción adversa al propiltiouracilo. Luego de ser tratada la paciente se recupera de su gravedad con el uso de factores estimulantes de colonias de granulocitos(AU)

A female 33-year-old patient with an 8-year history of diffuse thyroid goiter presents at the emergency service with shortness of breath, a 39-40ºC fever, a sore throat and palpitation of 3 days' evolution. Physical examination revealed exophthalmos, hypopigmented mucosas, a purulent pharynx dotted with whitish spots, arthralgia and tachycardia. Complementary tests found anemia, leukopenia and pancytopenia upon consumption of propylthiouracil (50 mg) for a long period. The diagnosis is agranulocytosis resulting from an adverse reaction to propylthiouracil. After being treated the patient recovered from her severe status with the use of granulocyte colony stimulating factors(AU)

Effect of melatonin on gonad and thyroid development of offspring of hypothyroid pregnant rats.

We investigated the effects of melatonin on rats with induced hypothyroidism during gestation as well as its effect on the development of the gonads of their offspring. Fifteen pregnant rats were divided into three groups: GC, rats without induced hypothyroidism; GH, rats with induced hypothyroidism; GHM, rats with induced hypothyroidism plus melatonin. Hypothyroidism was induced by oral administration of 6-propyl-2-thiouracil and melatonin was applied subcutaneously. Treatments were performed during gestation and lactation. For the matrices, we evaluated the number of pups, body weight gain, ovarian weight, thyroid weight, organosomatic index, thyroid stimulating hormone (TSH) dose and thyroid morphometry. For the pups, weight gain, TSH, weight, morphometry of the gonads and organosomatic index were analyzed, as well as the cell proliferation index. TSH was elevated only in the matrices of GH animals. Melatonin prevented reduction of ovarian and thyroid weight, number of pups, follicular diameter and thyroid epithelial proportion of the matrices with hypothyroidism. The offspring of rats of the GH group exhibited less body weight gain, gonad and thyroid weight, and gonad cell proliferation index compared to the offspring born of rats of the GC and GHM groups. Melatonin prevented the effects of maternal hypothyroidism on the offspring of rats.

Changes in the Stoichiometry of Uniplex Decrease Mitochondrial Calcium Overload and Contribute to Tolerance of Cardiac Ischemia/Reperfusion Injury in Hypothyroidism.

Background: Thyroid hormone status in hypothyroidism (HT) downregulates key elements in Ca2+ handling within the heart, reducing contractility, impairing the basal energetic balance, and increasing the risk of cardiovascular disease. Mitochondrial Ca2+ transport is reduced in HT, and tolerance to reperfusion damage has been documented, but the precise mechanism is not well understood. Therefore, we aimed to determine the stoichiometry and activity of the mitochondrial Ca2+ uniporter or uniplex in an HT model and the relevance to the opening of the mitochondrial permeability transition pores (mPTP) during ischemia/reperfusion (I/R) injury. Methods: An HT model was established in Wistar rats by treatment with 6-propylthiouracil for 28 days. Uniplex composition and activity were determined in cardiac mitochondria. Hearts were perfused ex vivo to induce I/R injury, and functional parameters related to contractility and tissue viability were evaluated. Results: The cardiac stoichiometry between two subunits of the uniplex (MICU1/MCU) increased by 25% in animals with HT. The intramitochondrial Ca2+ content was reduced by 40% and was less prone to the mPTP opening. After I/R injury, ischemic contracture and the onset of ventricular fibrillation were delayed in animals with HT, concomitant with a reduction in oxidative damage and mitochondrial dysfunction. Conclusions: Our results suggest that HT is associated with an increase in the cardiac MICU1/MCU ratio, thereby changing the stoichiometry between these subunits to increase the threshold to cytosolic Ca2+ and reduce mitochondrial Ca2+ overload. Our results also demonstrate that this HT model can be used to explore the role of mitochondrial Ca2+ transport in cardiac diseases due to its induced tolerance to cardiac damage.

Propylthiouracil-induced agranulocytosis as a rare complication of antithyroid drugs in a patient with Graves' disease.

INTRODUCTION: Graves' disease (GD) is an autoimmune disorder characterized by hyperthyroidism. Antithyroid drugs (ATDs) are available as therapy. Agranulocytosis is a rare but potentially fatal complication of this therapy. In this study, we report agranulocytosis induced by propylthiouracil (PTU) in a patient with GD and the difficulties of clinical management. CASE: RNBA, male, 30 years old, with GD, treated with propylthiouracil (PTU). He progressed with pharyngotonsillitis. Then, PTU was suspended and antibiotic, filgrastim, propranolol, and prednisone were initiated. Due to the decompensation of hyperthyroidism, lithium carbonate, dexamethasone, and Lugol's solution were introduced. Total thyroidectomy (TT) was performed with satisfactory postoperative progression. DISCUSSION: We describe here the case of a young male patient with GD. For the treatment of hyperthyroidism, thioamides are effective options. Agranulocytosis induced by ATDs is a rare complication defined as the occurrence of a granulocyte count <500/mm3 after the use of ATDs. PTU was suspended, and filgrastim and antibiotics were prescribed. Radioiodine (RAI) or surgery are therapeutic alternatives. Due to problems with ATD use, a total thyroidectomy was proposed. The preoperative preparation was performed with beta-blocker, glucocorticoid, lithium carbonate, and Lugol solution. Cholestyramine is also an option for controlling hyperthyroidism. TT was performed without postoperative complications. CONCLUSION: Thionamide-induced agranulocytosis is a rare complication. With a contraindication to ATDs, RAI and surgery are definitive therapeutic options in GD. Beta-blockers, glucocorticoids, lithium carbonate, iodine, and cholestyramine may be an adjunctive therapy for hyperthyroidism.

Prepubertal PTU treatment in rat increases Sertoli cell number and sperm production.

The number of Sertoli cells (SCs) ultimately determines the upper limit of sperm production in the testis. Previous studies have shown that thyroid hormones (TH) receptors are abundantly expressed in developing SCs; therefore, it was highly significant to discover that transient neonatal hypothyroidism induced by the goitrogen 6-n-propyl-2-thiouracil (PTU) can extend SCs proliferation beyond the first 2 weeks postnatal and increase testis weight and sperm production. Further studies concluded that treatment must begin before day 8 post birth in rats. Recent studies, however, showed that SCs present in the transition region at the rete testis exhibit a more immature phenotype and have prolonged mitotic activity, which led to the hypothesis that SCs in this region will retain the capacity to respond to PTU treatment over a longer period of time. In the present study, male Wistar rats were treated with PTU from days 21 to 40 and were evaluated at 40 and 160 days of age. Similar to neonatal rat SCs, it was demonstrated that prepubertal SCs in the transition region have a high mitotic activity and are highly sensitive to TH levels. This delayed, transient hypothyroidism resulted in significantly increased testis weight, SCs number and daily sperm production. The results demonstrate for the first time that Sertoli cells showing plasticity in the transition region can be stimulated to increase proliferation and contribute to a late stage surge in testis weight and sperm output.

Propylthiouracil-induced agranulocytosis as a rare complication of antithyroid drugs in a patient with Graves' disease

SUMMARY INTRODUCTION: Graves' disease (GD) is an autoimmune disorder characterized by hyperthyroidism. Antithyroid drugs (ATDs) are available as therapy. Agranulocytosis is a rare but potentially fatal complication of this therapy. In this study, we report agranulocytosis induced by propylthiouracil (PTU) in a patient with GD and the difficulties of clinical management. CASE: RNBA, male, 30 years old, with GD, treated with propylthiouracil (PTU). He progressed with pharyngotonsillitis. Then, PTU was suspended and antibiotic, filgrastim, propranolol, and prednisone were initiated. Due to the decompensation of hyperthyroidism, lithium carbonate, dexamethasone, and Lugol's solution were introduced. Total thyroidectomy (TT) was performed with satisfactory postoperative progression. DISCUSSION: We describe here the case of a young male patient with GD. For the treatment of hyperthyroidism, thioamides are effective options. Agranulocytosis induced by ATDs is a rare complication defined as the occurrence of a granulocyte count <500/mm3 after the use of ATDs. PTU was suspended, and filgrastim and antibiotics were prescribed. Radioiodine (RAI) or surgery are therapeutic alternatives. Due to problems with ATD use, a total thyroidectomy was proposed. The preoperative preparation was performed with beta-blocker, glucocorticoid, lithium carbonate, and Lugol solution. Cholestyramine is also an option for controlling hyperthyroidism. TT was performed without postoperative complications. CONCLUSION: Thionamide-induced agranulocytosis is a rare complication. With a contraindication to ATDs, RAI and surgery are definitive therapeutic options in GD. Beta-blockers, glucocorticoids, lithium carbonate, iodine, and cholestyramine may be an adjunctive therapy for hyperthyroidism.

RESUMO INTRODUÇÃO: A doença de Graves (DG) é uma doença autoimune caracterizada por hipertireoidismo. As drogas antitireoidianas (DAT) são opções terapêuticas disponíveis. A agranulocitose é uma complicação rara, potencialmente fatal desta terapia. Neste estudo, relatamos um caso de agranulocitose induzida por propiltiouracil (PTU) em paciente com DG e as dificuldades do manejo clínico. RELATO DE CASO: RNBA, sexo masculino, 30 anos, com DG, tratado com PTU. Evoluiu com faringoamigdalite, sendo o PTU suspenso e antibióticos, filgrastim, propranolol e prednisona, iniciados. Devido à descompensação do hipertireoidismo, iniciou carbonato de lítio (CL), dexametasona e a solução de Lugol. A tireoidectomia total (TT) foi realizada com boa evolução pós-operatória. DISCUSSÃO: Descrevemos caso de paciente jovem, sexo masculino, com DG. Para o tratamento do hipertireoidismo, as tionamidas são opções efetivas. A agranulocitose induzida por DATs é uma complicação rara, definida como a ocorrência de contagem de granulócitos <500/mm3 após uso de dats. PTU foi suspenso e foram prescritos filgrastim e antibiótico. O radioiodo (RAI) ou a cirurgia são alternativas terapêuticas. Devido a problemas com o uso de DAT, a TT foi proposta. A preparação pré-operatória foi realizada com betabloqueador, glicocorticoide, CL e solução de Lugol. A colestiramina também é uma opção para controlar o hipertireoidismo. A TT foi realizada sem complicações pós-operatórias. CONCLUSÃO: A agranulocitose induzida por drogas antitireoidianas é uma complicação rara. Com a contraindicação às DATs, RAI e cirurgia são opções terapêuticas definitivas para DG. Os betabloqueadores, glicocorticoides, CL, iodo e a colestiramina podem ser uma terapia adjuvante para o hipertireoidismo.

High Thyrotropin Is Critical for Cardiac Electrical Remodeling and Arrhythmia Vulnerability in Hypothyroidism.

Background: Hypothyroidism, the most common endocrine disease, induces cardiac electrical remodeling that creates a substrate for ventricular arrhythmias. Recent studies report that high thyrotropin (TSH) levels are related to cardiac electrical abnormalities and increased mortality rates. The aim of the present work was to investigate the direct effects of TSH on the heart and its possible causative role in the increased incidence of arrhythmia in hypothyroidism. Methods: A new rat model of central hypothyroidism (low TSH levels) was created and characterized together with the classical propylthiouracil-induced primary hypothyroidism model (high TSH levels). Electrocardiograms were recorded in vivo, and ionic currents were recorded from isolated ventricular myocytes in vitro by the patch-clamp technique. Protein and mRNA were measured by Western blot and quantitative reverse transcription polymerase chain reaction in rat and human cardiac myocytes. Adult human action potentials were simulated in silico to incorporate the experimentally observed changes. Results: Both primary and central hypothyroidism models increased the L-type Ca2+ current (ICa-L) and decreased the ultra-rapid delayed rectifier K+ current (IKur) densities. However, only primary but not central hypothyroidism showed electrocardiographic repolarization abnormalities and increased ventricular arrhythmia incidence during caffeine/dobutamine challenge. These changes were paralleled by a decrease in the density of the transient outward K+ current (Ito) in cardiomyocytes from animals with primary but not central hypothyroidism. In vitro treatment with TSH for 24 hours enhanced isoproterenol-induced spontaneous activity in control ventricular cells and diminished Ito density in cardiomyocytes from control and central but not primary hypothyroidism animals. In human myocytes, TSH decreased the expression of KCND3 and KCNQ1, Ito, and the delayed rectifier K+ current (IKs) encoding proteins in a protein kinase A-dependent way. Transposing the changes produced by hypothyroidism and TSH to a computer model of human ventricular action potential resulted in enhanced occurrence of early afterdepolarizations and arrhythmia mostly in primary hypothyroidism, especially under ß-adrenergic stimulation. Conclusions: The results suggest that suppression of repolarizing K+ currents by TSH underlies most of the electrical remodeling observed in hypothyroidism. This work demonstrates that the activation of the TSH-receptor/protein kinase A pathway in the heart is responsible for the cardiac electrical remodeling and arrhythmia generation seen in hypothyroidism.

Patrones de prescripción de medicamentos antitiroideos en una población de Colombia / Patterns of prescription of antithyroid drugs in a Colombian population

Resumen Introducción: en Colombia no se conoce la prevalência de los trastornos asociados a tirotoxicosis ni se dispone de estudios fármacoepidemiológicos acerca de la prescripción de los medicamentos antitiroideos. Objetivo: determinar los patrones de prescripción de los antitiroideos y variables asociadas a su uso en una población de pacientes en Colombia. Métodos: estudio de corte transversal, realizado entre enero 1 y marzo 30 de 2015 sobre los hábitos de prescripción de medicamentos antitiroideos en una población afiliada al sistema de salud colombiano. Se midieron variables sociodemográficas, farmacológicas y de comedicación. Se diseñó una base de datos sobre el consumo de medicamentos y se utilizaron pruebas t de student, X 2 y modelos de regresión logística. Resultados: un total de 327 pacientes en tratamiento con medicamentos antitiroideos fueron incluidos. La edad media fue de 53.7±18.1 años y 78.3% de pacientes correspondió a mujeres. El metimazol se prescribió en 95.4% de los pacientes, el propiltiouracilo en 4.6%. En 76.8% de pacientes se presentó comedicación; en particular con antihipertensivos (38.2%) y adicionalmente con propranolol (34.3%). Conclusiones: la tendencia de prescripción de medicamentos antitiroideos en Colombia es similar a lo reportado en diferentes estudios a nivel mundial. El principal medicamento antitiroideo es metimazol, con una tasa de uso mayor a la reportada en Norteamérica y en estudios europeos. Las dosis del metimazol y de propiltiouracilo reportadas en este estudio se ajustan a las recomendaciones de la Asociación Americana de Endocrinología Clínica.

Abstract Introduction: the prevalence of disorders associated with thyrotoxicosis is not known in Colombia, nor pharmacoepidemiological studies are available on the prescription of antithyroid drugs. Objective: to determine the prescription patterns of antithyroid drugs and variables associated with their use in a population of Colombian patients. Methods: cross-sectional study, conducted between January 1 and March 30, 2015 on the prescription habits of antithyroid drugs in a population affiliated with the Colombian Health System. Sociodemographic, pharmacological and comedication variables were measured. A database on drug consumption was designed and student t-tests, X 2 and logistic regression models were used. Results: a total of 327 patients in treatment with antithyroid drugs were included. The mean age was 53.7 ± 18.1 years and 78.3% of patients corresponded to women. Methimazole was prescribed in 95.4% of patients, propylthiouracil in 4.6%. In 76.8% of patients, comedication was present in particular with antihypertensive agents (38.2%) and additionally with propranolol (34.3%). Conclusions: the prescription tendency of antithyroid drugs in Colombia is similar to that reported in different studies worldwide. The main antithyroid drug is methimazole, with a rate of use higher than that reported in North America and in European studies. The doses of methimazole and propylthiouracil reported in this study are in accordance with the recommendations of the American Association of Clinical Endocrinology.

Experimentally-induced maternal hypothyroidism alters enzyme activities and the sensorimotor cortex of the offspring rats.

In this study, we used an experimental model of congenital hypothyroidism to show that deficient thyroid hormones (TH) disrupt different neurochemical, morphological and functional aspects in the cerebral cortex of 15-day-old offspring. Our results showing decreased glutamine synthetase (GS) activity and Ca2+ overload in the cerebral cortex of hypothyroid pups suggest misregulated glutamate metabolism associated with developmentally induced TH deficiency. The 14C-MeAIB accumulation indicates upregulated System A activity and glutamine uptake by neurons. Energy metabolism in hypothyroid cortical slices was preserved, as demonstrated by unaltered glucose metabolism. We also found upregulated acetylcholinesterase activity, depleting acetylcholine from the synaptic cleft, pointing to disrupted cholinergic system. Increased reactive oxygen species (ROS) generation, lipid peroxidation, glutathione (GSH) depletion, which were associated with glutathione peroxidase, superoxide dismutase and gamma-glutamyltransferase downregulation suggest redox imbalance. Disrupted astrocyte cytoskeleton was evidenced by downregulated and hyperphosphorylated glial fibrillary acidic protein (GFAP). Morphological and structural characterization of the sensorimotor cerebral cortex (SCC) showed unaltered thickness of the SCC. However, decreased size of neurons on the layers II & III and IV in the right SCC and increased NeuN positive neurons in specific SCC layers, suggest that they are differently affected by the low TH levels during neurodevelopment. Hypothyroid pups presented increased number of foot-faults in the gridwalk test indicating affected motor functions. Taken together, our results show that congenital hypothyroidism disrupts glutamatergic and cholinergic neurotransmission, Ca2+ equilibrium, redox balance, cytoskeleton integrity, morphological and functional aspects in the cerebral cortex of young rats.

Time-intensity and reaction-time methodology applied to the dynamic perception and liking of bitterness in relation to body mass index.

There are very few studies which have considered perception temporality when relating perceived intensity and hedonic responses in relation to body mass index (BMI; kg/cm2). The aim of the present study was to determine the relationship between BMI with the dynamic perception and liking of bitter tasting solutions. For this purpose, two different categories of bitter products were applied: 6-n-propilthiouracil (PROP) solutions (0.010, 0.032 and 0.060 mmol/L) and commercial beverages (coffee, yerba mate infusion and grapefruit juice). The proposed methodology to evaluate perception and hedonic response was based on the measurement of reaction-time (R-T) and multiple-sip time-intensity (T-I) registers in people with a high BMI (25 < BMI < 30; overweight group) and a normal BMI (<25; normal-weight control group). The multiple-sip evaluation to describe perception of PROP solutions and liking of beverages was used as a more ecologically valid laboratory methodology to simulate a situation of usual consumption. In this sense, working with a multiple-sip design helped confirm that bitter taste has a cumulative effect since in every case the sip effect was significant when evaluating the maximum intensity; this effect was more important as the bitterness increased. Regarding the body weight group comparisons, the normal BMI group perceived bitter taste more intensely and the time to react to it was shorter (faster reaction) for both PROP solutions and the three beverages. Interestingly, even though the high BMI group rated the bitter taste as less intense, they had a lower level of acceptance than normal BMI. This result suggests that the hedonic rather than the sensory component might be playing a crucial role in the perception of bitter taste in individuals with high BMI.

High-fat diet affects gut nutrients transporters in hypo and hyperthyroid mice by PPAR-a independent mechanism.

AIMS: High fat diet consumes and thyroid hormones (THs) disorders may affect nutrients metabolism, but their impact on the absorptive epithelium, the first place of nutrients access, remains unknown. Our aim was to evaluate the intestinal morphology and nutrients transporters content in mice fed standard (LFD) or high fat (HFD) diets in hypo or hyperthyroidism-induced condition. MATERIAL AND METHODS: C57BL/6 male mice fed LFD or HFD diets for 12 weeks, followed by saline, PTU (antithyroid drug) or T3 treatment up to 30 days. The mice were euthanized and proximal intestine was removed to study GLUT2, GLUT5, PEPT1, FAT-CD36, FATP4, NPC1L1 and NHE3 distribution by Western blotting. Since PPAR-a is activated by fatty acids, which is abundant in the HFD, we also evaluated whether PPAR-a affects nutrients transporters. Thus, mice were treated with fenofibrate, a PPAR-a agonist. KEY FINDINGS: HFD decreased GLUT2, PEPT1, FAT-CD6 and NPC1L1, but increased NHE3, while GLUT5 and FATP4 remained unaltered. THs did not alter distribution of nutrients transporters neither in LFD nor in HFD groups, but they increased villi length and depth crypt in LFD and HFD, respectively. Fenofibrate did not affect content of nutrients transporters, excluding PPAR-a involvement on the HFD-induced changes. SIGNIFICANCE: We assume that chronic HFD consumption reduced most of the nutrients transporters content in the small intestine of mice, which might limit the entrance of nutrients and gain weight. Since NHE3 promotes sodium absorption, and it was increased in HFD group, this finding could contribute to explain the hypertension observed in obesity.

Neutropenia severa inducida por propiltiuracilo / (Severe neutropenia induced by propylthiuracil)

Resumen Los pacientes con hipertiroidismo tienen varias opciones de tratamiento. El tratamiento de la enfermedad de Graves consiste en bloquear el exceso de hormonas tiroideas empleando tionamidas, tiroidectomía o terapia con I131. Los agentes antitiroideos como el metimazol, carbimazole, propiltiuracilo, son efectivos para controlar el hipertirodismo en pacientes con enfermedad de Graves, pero tienen efectos adversos incluyendo, alergias, gastritis, hepatitis y agranulocitosis. Se presenta un paciente hipertiroideo con neutropenia severa durante tratamiento con propiltiuracilo.

Abstract Patients with hyperthyroidism have several treatment options. The treatment of Graves' disease consists of blocking the excess of thyroid hormones using thionamides, thyroidectomy or I131 therapy. Antithyroid agents such as methimazole, carbimazole, propylthiuracil are effective in controlling hyperthyroidism in patients with Graves' disease, but they have adverse effects including, allergies, gastritis, hepatitis and agranulocytosis. We present a hyperthyroid patient with severe neutropenia during treatment with propylthiuracil.