Thyroid Morphology Research Articles

Lycopene ameliorates the effect of Aroclor 1254 on morphology, proliferation, and angiogenesis of the thyroid gland in rat

Aroclor 1254 is a mixture of polychlorinated biphenyls that are reported to disrupt thyroid hormone homeostasis, yet little is known on its effect on thyroid gland microarchitecture. Lycopene is a commonly used potent antioxidant. This study is a biochemical, histological, and immunohistochemical assessment of the effect of Aroclor 1254 on the morphology, proliferation, and angiogenesis of the thyroid gland in rat and to evaluate the possible ameliorating role of lycopene. Twenty-four adult male albino rats were divided into 4 groups; Control, lycopene-treated (4 mg/kg/day orally for 30 days), Aroclor 1254-treated (2 mg/kg/day intraperitoneally for 30 days), and lycopene & Aroclor 1254-treated group. Serum thyroid hormones, thyroid-stimulating hormone (TSH), and tissue malondialdehyde (MDA) were quantified. Thyroid specimens were processed for histological staining with hematoxylin and eosin, periodic acid-Schiff, and Mallory’s trichrome stains as well as immunohistochemical staining for detection of calcitonin, Ki67, and VEGF. In this study, Aroclor 1254-treated animals recorded a significant decline in both serum T3 and T4 coupled with a significant elevation in both TSH and tissue MDA. Histological sections showed small irregular follicles with the formation of hyperplastic and micro follicles. Some follicular and parafollicular cells depicted nuclear and cytoplasmic alterations associating with scanty or absent colloid in addition to signs of inflammation and fibrosis. A significant upregulation in the immunohistochemical expression of calcitonin, Ki67, and VEGF was recorded. Lycopene co-treatment successfully reinstated the values of most studied parameters and retrieved a near-control thyroid morphology. In conclusion, Aroclor 1254 impacted the thyroid hormone homeostasis, morphology, proliferation, and angiogenesis of the thyroid gland in rat, while lycopene efficiently ameliorated these adverse effects.

Thyroid disrupting effects of low-dose dibenzothiophene and cadmium in single or concurrent exposure: New evidence from a translational zebrafish model

Thyroid hormones (THs) are major regulators of biological processes essential for correct development and energy homeostasis. Although thyroid disruptors can deeply affect human health, the impact of exogenous chemicals and in particular mixture of chemicals on different aspects of thyroid development and metabolism is not yet fully understood. In this study we have used the highly versatile zebrafish model to assess the thyroid axis disrupting effects of cadmium (Cd) and dibenzothiophene (DBT), two environmental endocrine disruptors found to be significantly correlated in epidemiological co-exposure studies. Zebrafish embryos (5hpf) were exposed to low concentrations of Cd (from 0.05 to 2 μM) and DBT (from 0.05 to 1 μM) and to mixtures of them. A multilevel assessment of the pollutant effects has been obtained by combining in vivo morphological analyses allowed by the use of transgenic fluorescent lines with liquid chromatography mass spectrometry determination of TH levels and quantification of the expression levels of key genes involved in the Hypothalamic-Pituitary-Thyroid Axis (HPTA) and TH metabolism. Our results underscore for the first time an important synergistic toxic effect of these pollutants on embryonic development and thyroid morphology highlighting differences in the mechanisms through which they can adversely impact on multiple physiological processes of the HPTA and TH disposal influencing also heart geometry and function.

Imbalance of Autophagy and Apoptosis Induced by Oxidative Stress May Be Involved in Thyroid Damage Caused by Sleep Deprivation in Rats.

Many studies have shown that sleep deprivation can affect a wide range of tissues and organs, and most of these effects are related to oxidative stress. Oxidative stress can cause functional and morphological changes in cells, which are closely related to autophagy and apoptosis. In this study, we examined changes in thyroid morphology and function, oxidative stress, autophagy, and apoptosis in rats after sleep deprivation. Thyroid hormones, thyroid-stimulating hormone, functional substances required for the synthesis of thyroid hormones, and thyroid morphological observations were used to evaluate the changes and impairment of thyroid function. Methane dicarboxylic aldehyde and total antioxidant capacity were measured to assess oxidative stress in the thyroid. To evaluate the balance of autophagy and apoptosis, the expression of autophagy- and apoptosis-related proteins was examined by western blotting, and apoptotic cells were labeled with TUNEL staining. The body weight of rats in the sleep deprivation group decreased, but the relative weight of the thyroid gland increased. Sleep deprivation led to morphological changes in the thyroid. The levels of thyroid hormones and thyroid-stimulating hormone increased after sleep deprivation. Total antioxidant capacity decreased, and methane dicarboxylic aldehyde levels increased in the thyroid in the sleep deprivation group. Analysis of autophagy- and apoptosis-related proteins indicated that the microtubule-associated protein 1 light chain 3 beta- (LC3B-) and LC3A-II/I ratio and Beclin 1 levels significantly decreased in the sleep deprivation group and P62 levels significantly increased. The number of apoptotic cells in the thyroid gland of sleep-deprived rats increased significantly. Taken together, these results indicate that sleep deprivation can lead to oxidative stress in the thyroid and ultimately cause thyroid damage, which may be related to the imbalance of autophagy and apoptosis.

Features of the thyroid gland morphology of some representatives of the Cervidae family, living in the Altai

The authors studied the morphofunctional (anatomical and histological) features of the thyroid gland of dapple deer, maral, moose and roe deer. During the macroscopic examination of the organ, the number of lobes, the presence of an isthmus, the length, width and thickness of the lobes, and the weight of the gland were determined. During histological examination, morphometric parameters were evaluated, such as: diameter of the follicles, height of the thyrocytes, volume of the thyrocyte nuclei, and the Brown index was calculated. In all animals, the thyroid gland consisted of two lobes without an isthmus. It differs between species in the shape, size, and thickness of the lobes. The gland weight correlates with the size of the animals. Morphological differences between species consist in the heterogeneity of the location of follicles of different diameters in relation to each other. In the dapple deer, large-diameter follicles are located in the center of the organ, and smaller-diameter follicles are located both in the center and on the periphery. In roe deer, the gland follicles are almost identical in shape and size, that is, they are of the same type. The gland has a similar morphological structure in maral and moose. The colloid of the follicles has a homogeneous consistency, it is compacted and intensively stained with hematoxyl-eosin, resorption vesicles are in small quantities.

Thyroid redox imbalance in adult Wistar rats that were exposed to nicotine during breastfeeding

Maternal nicotine exposure causes several consequences in offspring phenotype, such as obesity and thyroid dysfunctions. Nicotine exposure can increase oxidative stress levels, which could lead to thyroid dysfunction. However, the mechanism by which nicotine exposure during breastfeeding leads to thyroid gland dysfunction remains elusive. We aimed to investigate the long-term effects of maternal nicotine exposure on redox homeostasis in thyroid gland, besides other essential steps for thyroid hormone synthesis in rats from both sexes. Lactating Wistar rats were implanted with osmotic minipumps releasing nicotine (NIC, 6 mg/kg/day) or saline (control) from postnatal day 2 to 16. Offspring were analyzed at 180-day-old. NIC males showed lower plasma TSH, T3 and T4 while NIC females had higher T3 and T4. In thyroid, NIC males had higher sodium-iodide symporter protein expression, whereas NIC females had higher thyroid-stimulating hormone receptor (TSHr) and thyroperoxidase (TPO) protein expression. TPO activity was lower in NIC males. Hydrogen peroxide generation was decreased in NIC males. Activities of superoxide dismutase, catalase and glutathione peroxidase were compromised in NIC animals from both sexes. 4-Hydroxynonenal was higher only in NIC females, while thiol was not affected in NIC animals from both sexes. NIC offspring also had altered expression of sex steroid receptors in thyroid gland. Both sexes showed similar thyroid morphology, with lower follicle and colloid size. Thyroid from female offspring exposed to nicotine during breastfeeding developed oxidative stress, while the male gland seemed to be protected from redox damage. Thyroid dysfunctions seem to be associated with redox imbalance in a sex-dependent manner.

Histogical structure of the thyroid gland in rabbits with different types of autonomous tonus

The research was aimed at investigating the influence of the aggregated tonus of sympathetic and parasympathetic centers on the rabbit’s thyroid gland morphology. For this purpose, the rabbit males (Oryctolagus cuniculus (Linnaeus, 1758)) of Blanc de Termond breed at the age of four months, passed an electrocardiographic and variation pulsometry study. According to the results, the animals were divided into three groups: rabbits with sympathicotonia (18 animals), rabbits with normotonia (5 animals) and rabbits with parasympathicotonia (3 animals). After euthanasia, the fragments of the thyroid gland were taken out, fixed in Bouin’s solution and embedded in paraffin blocks. Histological sections were prepared from the paraffin blocks and later stained with hematoxylin and eosin, as well as Gabu-Diban’s aldehyde fuchsin and Heidenhain’s azan. Morphometric study of follicles and cells of the gland was performed using these histopreparations. Based on the obtained data, the indices of gland activity were calculated, i.e. Brown index and the follicle-colloid index. At the same time, it was established that morphofunctional parameters of the thyroid gland depend on the typological features of the autonomous tonus. This is reflected in the thickness of the capsule, the amount of adipose tissue, the size and density of the follicles’ placement, the height of the thyrocytes and the ratio between the areas of their nuclei and the cytoplasm. Rabbits with parasympathicotonia account for the higher values of half (7 from 14) of the studied parameters, while their combination suggests the functional activity of the thyroid gland of the animals in this group is higher compared to the other groups of rabbits. Also, rabbits with parasympathicotonia have a larger body weight. For normotonic and sympatheticontic rabbits, the functional activity of the thyroid gland as well as the body weight is lower and approximately of the same intensity. The existence of correlation between the separate indicators was investigated, the character of which is also related to the type of the autonomous tonus.

Protective role of selenium on thyroid morphology in iodine-induced autoimmune thyroiditis in Wistar rats.

Excess iodine may induce and exacerbate autoimmune thyroiditis (AIT) in humans and animals. In order to assess the potential protective mechanisms of selenium (Se) in thyroid autoimmunity, the effects of inorganic Se (sodium selenite) administration on thyroid morphology and follicular cytology were investigated in adult Wistar rats with iodine-induced AIT. A total of 48 adult Wistar rats (24 females, 24 males) were allocated to one of four dietary regimens: C0, control; C1, only potassium iodine (KI); C2, concomitant KI and Se; C3, only KI initially, followed by Se administration. For AIT induction the rats were fed with 0.05% KI for 56 days. Se-treated rats received 0.3 mg/l sodium selenite in drinking water. Thyroid tissues were collected for pathologic diagnosis after 7 days in C0 group, 56 days in C1 and C2 groups, and 112 days in C3 group. In C1 group, moderate to severe thyroiditis was observed in 83% of males and 50% of female rats (P=0.223). In C3 group 16.7% of male rats developed moderate thyroiditis and none in C2 group, whereas no females were identified with moderate to severe thyroiditis in C2 or C3 group. Thus, the administration of Se was proven to have protective effects against thyroiditis cytology in both male and female Wistar rats.

Migraine and tension headache comorbidity with hypothyroidism in Egypt

BackgroundMigraine, tension type headache (TTH), and hypothyroidism are clinical problems that affect patient daily activities and quality of life.ObjectivesThe purpose of this study was to investigate the potential association between hypothyroidism in patients with migraine and TTH.Patients and methodsTwo hundred and twelve patients with migraine and TTH and one hundred control subjects underwent clinical evaluation, assessment of thyroid hormones, and thyroid ultrasound.ResultsSubclinical and overt hypothyroidism were significantly higher in patients with migraine and TTH (P = 0.001) than control subjects. Patients with migraine and TTH showed significantly more abnormal thyroid gland morphology than healthy control (P = 0.027). Hypothyroidism is significantly expressed in chronic TTH more than TTH with infrequent or frequent TTH (P = 0.009).ConclusionsPatients having migraine and TTH more prone to develop hypothyroidism when compared with control group. Also patients with chronic TTH are susceptible to develop hypothyroidism (either subclinical or overt) when compared with patients having frequent or infrequent TTH.

Sonography monitoring of thyroid morphology and function in patients with metastatic renal cell carcinoma treated with targeted drugs.

The incidence rate of renal cell carcinoma (RCC) has gradually increased worldwide over the past decade. Targeted therapy is the primary method for treating metastatic renal cell carcinoma (mRCC), and the development of thyroid dysfunction is one of the most common adverse reactions of this treatment. Therefore, this study aimed to assess the value of sonography in monitoring the morphology and functions of the thyroid in metastatic renal cell carcinoma patients treated with targeted drugs. In total, 37 patients from September 2016 to April 2019 with clinically confirmed mRCC that were treated with targeted drugs (19 with sunitinib and 18 with sorafenib) were enrolled in this study. The enrolled patients were divided into the hypothyroidism group and the non-hypothyroidism groups according to the changes in the serum concentration of the thyroid-stimulating hormone (TSH) during the treatment period. The serum concentrations of free triiodothyronine (FT3), free thyroxine (FT4), and TSH were measured by the Roche method before and after treatment. Simultaneously, the major axis, transverse diameter, and anteroposterior diameter of the bilateral lobes and isthmus of the thyroid gland were measured by ultrasound, and every thyroid volume was calculated. The changes in the thyroid volume, the thyroid volume change rate, and the homochronous serum concentration of TSH, FT3, FT4 in the hypothyroidism group, and the non-hypothyroidism group were then compared to assess the value of using sonography for monitoring the changes of thyroid morphology and functions. In total, 20 patients had hypothyroidism (hypothyroidism group), while 17 patients did not have hypothyroidism (non-hypothyroidism group). The thyroid volumes in both groups decreased gradually after targeted therapy. In the 1st, 2nd, 3rd, 4th, 5th, 6th, 9th, and 12th month after the treatment, the rate of change in thyroid volume in the hypothyroidism group (n=20) was 0.84 (0.47)%, 3.36 (1.34)%, 6.95 (1.42)%, 8.57 (1.66)%, 9.15 (0.55)%, 10.40 (1.12)%, 13.30 (1.53)%, and 14.15 (1.85)%, respectively. In the non-hypothyroidism group (n=17), the thyroid volume change rates were 0.25 (0.11)%, 3.00 (1.81)%, 3.9 (0.75)%, 5.09 (1.81)%, 6.72 (1.81)%, 6.90 (1.35)%, 9.90 (1.35)%, and 10.60 (1.79)%, respectively. There were significant differences in the rate of change in thyroid volume between the hypothyroidism and non-hypothyroidism group after treatment (F =490.804, P=0.000). When the thyroid volume change rate reached 8.5%, the sensitivity, specificity, and accuracy of using ultrasound in evaluating the occurrence of hypothyroidism were 70.3%, 94.1%, and 75.0%, respectively. The area under the curve (AUC) of the receiver operating characteristic curve (ROC) was 0.845. Using ultrasound as a tool can precisely detect the reduction of thyroid volume induced by targeted drugs used in mRCC therapy. For mRCC patients treated with targeted drugs, the degree of thyroid volume reduction in patients with hypothyroidism is higher than those without hypothyroidism. Furthermore, the rate of thyroid volume change in patients with mRCC can indirectly monitor the changes in thyroid function after a targeted treatment in these patients. The degree of thyroid volume reduction of 8.5% was relatively sensitive, specific, and accurate for the diagnosis of hypothyroidism.

Association between puberty with thyroid morphology and function in women

Objective: To explore the effects of different puberty development stages on thyroid morphology and function in women. Methods: From October to November 2017, a multi-stage cluster sampling method was used to select one junior high school in Minhang district of Shanghai, Haimen city of Jiangsu province, Yuhuan city of Zhejiang province and Deqing county of Zhejiang province respectively. A total of 491 girls in the first grade in 4 schools were included in the study. The subjects were examined with thyroid B-ultrasound and physical examination, and their morning random urine samples and fasting blood samples were collected to detect urinary iodine and thyroid function indexes. Puberty Development Self-rating Scale (PDS) was used to evaluate the stages of puberty; multiple linear regression models and logistic regression models were used to investigate the effects of different puberty stages on thyroid morphology and function. Results: There were differences in thyroid status among women at different stages of puberty. Thyroid volume, the rate of nodules and the level of FT4 were lowest in prepubertal period, followed by pubertal period and postpubertal period (P<0.05). TT3 and FT3 levels were highest in prepubertal period, followed by pubertal period and postpubertal period (P<0.001), and there was an opposite trend on the abnormal rate. TSH and TT4 levels were not affected by the stage of puberty (P>0.05). Multiple linear regression analysis and multivariate logistic regression analysis showed consistent results. There was a negative correlation between puberty development and TT3 and FT3 levels. For each 1 point increase in PDS, TT3 and FT3 levels decreased by 0.067 nmol/L and 0.170 nmol/L in Model 1, respectively, and decreased by 0.065 nmol/L and 0.162 nmol/L in Model 2, respectively. Compared with the prepubertal period, the TT3 and FT3 levels were lower in postpubertal period (Model 1: OR=0.337, 95%CI: 0.173-0.658; OR=0.283, 95%CI: 0.144-0.557; Model 2: OR=0.306, 95%CI: 0.155-0.605; OR=0.263, 95%CI: 0.132-0.524). Conclusions: The process of puberty is related to the thyroid status in women. The better matured during the puberty, the larger volume the thyroid was, more likely the thyroid nodules appeared, and the levels of TT3 and FT3 was much lower.

Complicated Relationship between Genetic Mutations and Phenotypic Characteristics in Transient and Permanent Congenital Hypothyroidism: Analysis of Pooled Literature Data.

Purpose Mutations and phenotypic characteristics remain unclear in patients with congenital hypothyroidism (CH), and no study concerning whether the outcome of transient CH (TCH) or permanent CH (PCH) is determined by mutations has been reported. Methods We searched the literature up to April 2019. Eligible studies and data extraction were performed. We estimated the relationship between mutations and phenotypic characteristics in pooled patients with CH. Results Two hundred forty-one cases were pooled from 41 eligible studies. The thyroid morphology, classification of mutated genes, and types of mutations were different between 94 patients with TCH and 147 patients with PCH. Heterozygous missense mutations prevailed in PAX8, TSHR, FOXE1, and NKX2-5, and patients with these mutated genes had a higher risk of PCH (OR = 37.38, 95% CI 5.04–277.21, P < 0.001). TCH and PCH have equal shares in patients with mutated DUOX2 or DUOXA2. Dual-site and multisite mutations were frequently detected in DUOX2. High phenotypic heterogeneity was observed in mutated DUOX2 even in the same mutations. However, there was no relationship found between mutations and transient or permanent outcome in patients with mutated DUOX2. Conclusion Transient or permanent outcomes were influenced by the biological function of mutated genes instead of types of mutations among patients with CH. Patients whose mutations were related to thyroid dysgenesis (TD) were more likely to have PCH. The relationship between mutations and phenotypic characteristics is complicated, and phenotypic characteristics may be affected by mutations and other factors.

Thyroid isthmus agenesis and its clinical significance in a large-scale multidetector CT-based study

ObjectiveThe purpose of this study was to estimate the incidence and clinical significance of thyroid isthmus agenesis based on multi-detector CT imaging in a large-scale study. MethodsData from 1601 patients who underwent neck multi-detector CT at our institution from January 2015 to March 2016 were included in this retrospective study. The morphology of each patient's thyroid gland was evaluated. We classified thyroid isthmus agenesis into two subgroups according to the thickness of the medial margin: clear-cut type (>4 mm) or tapering-edge type (≤4 mm). Associated thyroid pathologies were also evaluated. ResultsThyroid isthmus agenesis was present in 69 patients (41 males, 28 females), and its incidence was 4.77%. Eleven patients (0.76%) had the clear-cut type and 58 patients (4.01%) had the tapering-edge type. Papillary thyroid carcinoma was diagnosed in 4 patients (5.7% of isthmus agenesis patients). A total of 7 patients underwent thyroid function testing during the course of this study; 1 of these patients presented with borderline hyperthyroidism, and the remaining 6 were in a euthyroid state. The clear-cut type showed a statistically significant narrow gap and a high incidence of pyramidal lobes compared to the tapering-edge type. ConclusionThyroid isthmus agenesis is not a rare developmental anomaly of the thyroid gland on multi-detector CT. Based on the metastatic pathophysiology of differentiated thyroid cancer, more extended indications for lobectomy are expected in differentiated thyroid cancer patients with thyroid isthmus agenesis.

Potential toxic effects of TDCIPP on the thyroid in female SD rats

Objective: To investigate the potential toxic effects and mechanisms of Tris(1; 3-dichloro-2-propyl) phosphate (TDCIPP) on thyroid in female SD rats.Methods: Thirty-two 3-weeks-old female SD rats were randomly divided into normal group(treated with corn oil ), and low/moderate/high-dose group treated with TDCIPP (dissolved in corn oil )(n=8). All rats were treated with corn oil or TDCIPP (50, 100, 250 mg/(kg·d)) once a day during a 21-day period. All rats were sacrificed after the last administration. Serum thyroid stimulating hormone (TSH), 3,3',5-triiodothyronine (T3), 3,3',5,5'-tetraiodothyronine (T4), free 3,3',5,5'-tetraiodothyronine (FT4) were detected with ELISA kit. Morphology of thyroid was observed with hematoxylin and eosin (HE) staining. Expressions of genes and proteins correlate with thyroid were measured respectively by real-time fluorescence quantitative PCR and Western blot. Results: Compared with control group, morphology of thyroid showed follicles irregular arrangement, hypocolloid, and follicular hyperplasia in TDCIPP treatment groups. The levels of serum TSH in low-dose TDCIPP group and T3 in high-dose TDCIPP group were significantly higher than those in control group(P＜0.05). Thyroid stimulating hormone receptor (TSHR) mRNA expression was decreased distinctly in low-dose TDCIPP group, while the expression of thyroperoxidase (TPO) mRNA was increased notably in moderate and high-dose TDCIPP groups(P＜0.05,P＜0.01). Compared with control group, the level of TRβ protein was decreased significantly in moderate and high-dose TDCIPP groups, while the expressions of udp-glucuronosyl-transferases (UGTs) and cytochrome-p450-3A1 (CYP3A1) proteins were upregulated notably in TDCIPP treatment groups(P＜0.05). Conclusion: Treated with 50 mg/(kg·d) TDCIPP can cause thyroid hyperplasia, change the levels of thyroid hormones, and disturb thyroid function, therefore, it has toxic effects on the thyroid.

DUOX2 and DUOXA2 Variants Confer Susceptibility to Thyroid Dysgenesis and Gland-in-situ With Congenital Hypothyroidism.

Background: Thyroid dysgenesis (TD), which is caused by gland developmental abnormalities, is the most common cause of congenital hypothyroidism (CH). In addition, advances in diagnostic techniques have facilitated the identification of mild CH patients with a gland-in-situ (GIS) with normal thyroid morphology. Therefore, TD and GIS account for the vast majority of CH cases.Methods: Sixteen known genes to be related to CH were sequenced and screened for variations by next-generation sequencing (NGS) in a cohort of 377 CH cases, including 288 TD cases and 89 GIS cases.Results: In our CH cohort, we found that DUOX2 (21.22%) was the most commonly variant pathogenic gene, while DUOXA2 was prominent in TD (18.75%) and DUOX2 was prominent in GIS (34.83%). Both biallelic and triple variants of DUOX2 were found to be most common in children with TD and children with GIS. The most frequent combination was DUOX2 with DUOXA1 among the 61 patients who carried digenic variants. We also found for the first time that biallelic TG, DUOXA2, and DUOXA1 variants participate in the pathogenesis of TD. In addition, the variant p.Y246X in DUOXA2 was the most common variant hotspot, with 58 novel variants identified in our study.Conclusion: We meticulously described the types and characteristics of variants from sixteen known gene in children with TD and GIS in the Chinese population, suggesting that DUOXA2 and DUOX2 variants may confer susceptibility to TD and GIS via polygenic inheritance and multiple factors, which further expands the genotype-phenotype spectrum of CH in China.

Thyroid-disrupting effects and mechanism of thiazole-Zn-induced thyroid cell hypertrophy and hyperplasia in male Sprague-Dawley rats.

Thiazole-Zn is a systemic fungicide synthesized and developed in China that has been used for the prevention and treatment of bacterial and fungal diseases on fruits and vegetables. Thiazole-Zn is a new thyroid disruptor chemical. The purpose of this study was to clarify the thyroid-disrupting property of thiazole-Zn and the mechanism responsible for thyroid hormone (TH) biosynthesis inhibition in male rats induced by thiazole-Zn. First, the effects of different thiazole-Zn doses and exposure times on the thyroid weights, thyroid morphology and serum hormone levels of rats were investigated. The results showed that thiazole-Zn increased thyroid weights and serum thyroid-stimulating hormone (TSH) levels and induced thyroid cell hypertrophy and hyperplasia in a dose-related and time-related manner. Furthermore, measurement of thyroid radioiodine uptake in vivo in rats confirmed that thiazole-Zn inhibited active iodide uptake into the thyroid, which reduced circulating levels of serum T3 and T4. Decreases in circulating THs resulted in a compensatory increase in serum TSH levels through a negative feedback system. Subsequently, sustained excessive stimulation of the thyroid gland by TSH led to thyroid follicular cell hypertrophy and hyperplasia. In addition, thiazole-Zn increased sodium/iodide symporter (NIS) expression in the rat thyroid, and the increased NIS expression promoted and restored iodide uptake into the thyroids of rats. The risk of iodine intake inhibition by thiazole-Zn to humans, especially susceptible individuals, such as children and pregnant women, warrants additional attention.

Effect of cyclic heat stress on thyroidal hormones, thyroid histology, and performance of two broiler strains.

This study determined thyroid hormone (T3 and T4) serum levels and investigated thyroid gland histology, as well as two broiler strains performance kept at different periods of heat stress. Broilers (560 Cobb Slow™ and 560 Hubbard Flex™) were distributed in control environment (0) reared following the thermal recommendations, and environments 1, 2, and 3 exposed to high temperatures for 1h, 2h, and 3h a day, respectively, from 14 to 42days old. At 21, 28, 35, and 42days old, blood samples were collected to determine T3 and T4 serum levels. At 42days old, thyroid glands were removed for histological analyses. The performance was calculated weekly. T3 levels decreased with age advance, while T4 serum concentration was higher at 42days old (23.27nmolL-1) and lower at 28days old (15.69nmolL-1). The histological sections revealed that thyroid morphology was well preserved. Live weight was higher in Cobb Slow™ (2.97kg) than Hubbard Flex™ (2.93kg) broilers at 42days old. It is possible to conclude that cyclic heat stress exposure for a 3-h period from 14 to 42days old did not affect performance, thyroid histology, or T3 and T4 serum levels. Cobb Slow™ broilers had the best live weight values at slaughtering. With increasing age, T3 levels decreased and T4 levels increased for both strains.

Study on the clinical features of Hashimoto′s thyroiditis with elevated serum IgG4

Objective To investigate the clinical features of Hashimoto′s thyroiditis(HT) with elevated serum IgG4 levels and to guide the clinical practice. Methods Serum IgG4 concentrations were detected in patients with HT by nephelometric immunoassay. These patients were classified into two groups according to the IgG4 levels: positive group(IgG4≥1.35 g/L), and negative group(IgG4<1.35 g/L). The clinical characteristics of these two groups, including age, gender, medical history, serological features, and ultrasound were compared. Results Nine out of 111 patients with HT were positive with IgG4(8.11%), all of them were women. There was no significant difference in gender, age, BMI, dose of levothyroxine administration, FT3, FT4, and TSH levels between the two groups. The volume of thyroid in positive group was larger than that in negative group [57.81(38.36, 74.93) ml vs 25.07(18.48, 42.14) ml, P=0.015], and the level of thyroglobulin antibodies(TgAb; P=0.011) and thyroid peroxidase antibodies(TPOAb; P=0.025) in positive group were also significantly higher than those in negative group. Moreover, the positive group had a slightly higher risk of PTC than that of negative group(11.1% vs 2.94%, P=0.290), though the difference was not significant. Correlation analysis showed that IgG4 was positively associated with TgAb, TPOAb, and thyroid volume. Conclusions The levels of TgAb and TPOAb are higher, the volume of thyroid gland is greater, and the risk of PTC with lymph node metastasis is more frequent in HT patients with elevated serum IgG4. For HT patient with elevated serum IgG4, their thyroid function and morphology should be more closely monitored. Key words: IgG4; Hashimoto′s thyroiditis; Papillary thyroid carcinoma

BAZ1B is a candidate gene responsible for hypothyroidism in Williams syndrome.

Williams syndrome (WS) is a rare neurodevelopmental disorder associated to a hemizygous deletion of 28 genes located on chromosome 7q11.23. WS affected subjects frequently suffer from several endocrine abnormalities including hypothyroidism due to defects in thyroid morphology. To date, several genes involved in thyroid dysgenesis have been identified, nonetheless, none of them is located in the 7q11.23 region. Thus, the hypothyroidism-linked molecular features in WS are not yet known. In this study we focused on one of the WS deleted gene, BAZ1B, demonstrating that its downregulation in thyroid cells leads to cell viability and survival decrement. Taking together, our results show that BAZ1B could be the mainly responsible for thyroid defects observed in some of WS patients and that these alterations are activated by PTEN-mediated mechanisms.

Thyroid dysfunction in Congolese subjects with Down syndrome

Objective: The present study aims to assess the proportion and the pattern of thyroid dysfunction in a population of Congolese subjects with Down Syndrome. Methods: A total of 34 subjects with Down syndrome were recruited from Lubumbashi (Democratic Republic of Congo). Thyroid morphology was assessed by sonography. Serum T3, T4, FT4, TSH, Thyroglobulin, Thyroid peroxidase antibody (TPOAb) and antithyroglobulin antibody (TgAb) were measured. Results: The mean age of the patients was 13 years (range: 3 and 47 years). Of 34 Down syndrome subjects, 6 cases (17.6%) were found to have subclinical hypothyroidism. No patient had hyperthyroidism. Among 29 subjects with a thyroid ultrasound imaging, 25 patients (86.2%) were found to have morphological abnormalities of the gland. Regarding thyroid autoantibodies, TPOAb was positive in 1 case (2.9%) and TgAb was positive in 1 case (2.9%). The results were compared between patients with hypothyroidism and with normal thyroid function. There was no statistical difference in terms of age, sex, nutritional status, antibody levels and thyroid volume between these two groups. Conclusions: In our series, the proportion of hypothyroidism is relatively important but it remains largely under the prevalence reported in international studies.

Morphological and functional changes in neonatally X-irradiated thyroid gland in rats.

Exposure to ionized radiation in childhood has been recognized as a risk factor for the development of thyroid cancer and possibly for other thyroid disorders. However, the effects of neonatal radiation exposure on thyroid morphology and functions have never been explored despite its potential importance. One-week-old male Wistar rats were subjected to cervical X-irradiation at 6 and 12 Gy. Animals were examined at the ages of 2, 8 and 18 weeks old. For comparison, 8-week-old rats were cervically X-irradiated at the same doses. Thyroid histology was examined by computer-assisted microscopy to measure areas of colloid and epithelium of thyroid follicles as well as epithelial heights. In rats that received cervical X-irradiation at 1 week old, the colloid size of thyroid follicles decreased at the age of 8 weeks old in a radiation-dose dependent manner. This morphological change was persistently found at 18 weeks old. There were no significant differences in serum total T3 or T4 levels among the groups. Serum TSH levels increased significantly in 8-week-old rats neonatally X-irradiated. Thyroglobulin (Tg) mRNA and protein expressions were significantly decreased in the neonatally-irradiated group while thyroid peroxidase mRNA express increased at 18 weeks old. None of these changes were observed in the rats X-irradiated at 8 weeks old. In conclusion, our results clearly demonstrated that neonatal rat thyroid was sensitive to ionized radiation, developing specific morphological changes characterized by smaller thyroid follicles along with changes in serum TSH levels and Tg expressions in the thyroid tissue.