Chronic lymphocytic (Hashimoto's) thyroiditis in Kuwait diagnosed by fine needle aspirates

Synaptic loss in a mouse model of euthyroid Hashimoto's thyroiditis: possible involvement of the microglia

Background

Hashimoto’s thyroiditis (HT) is an autoimmune illness that renders individuals vulnerable to neuropsychopathology even in the euthyroid state, the mechanisms involved remain unclear. We hypothesized that activated microglia might disrupt synapses, resulting in cognitive disturbance in the context of euthyroid HT, and designed the present study to test this hypothesis.

Methods

Experimental HT model was induced by immunizing NOD mice with thyroglobulin and adjuvant twice. Morris Water Maze was measured to determine mice spatial learning and memory. The synaptic parameters such as the synaptic density, synaptic ultrastructure and synaptic-markers (SYN and PSD95) as well as the interactions of microglia with synapses were also determined.

Results

HT mice had poorer performance in Morris Water Maze than controls. Concurrently, HT resulted in a significant reduction in synapse density and ultrastructure damage, along with decreased synaptic puncta visualized by immunostaining with synaptophysin and PSD-95. In parallel, frontal activated microglia in euthyroid HT mice showed increased engulfment of PSD95 and EM revealed that the synaptic structures were visible within the microglia. These functional alterations in microglia corresponded to structural increases in their attachment to neuronal perikarya and a reduction in presynaptic terminals covering the neurons.

Conclusion

Our results provide initial evidence that HT can induce synaptic loss in the euthyroid state with deficits might be attributable to activated microglia, which may underlie the deleterious effects of HT on spatial learning and memory.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-022-00710-2.

Hashimoto's Thyroiditis Induces Hippocampus-Dependent Cognitive Alterations by Impairing Astrocytes in Euthyroid Mice

Background: Although studies have reported an increased risk for cognitive disorders in Hashimoto's thyroiditis (HT) patients, even in the euthyroid state, the mechanisms involved remain unclear. The hippocampus is a classic brain region associated with cognitive function, among which the formation of long-term potentiation (LTP) in the Schaffer collateral-CA1 pathway plays an important role in the process of learning and memory. Therefore, this study established a euthyroid HT model in mice and investigated whether and how HT itself has the ability to trigger LTP alterations accompanied by learning and memory abnormality. Methods: An experimental euthyroid HT model was established in NOD mice through immunization with porcine thyroglobulin (Tg). Morris water maze was measured to determine mice spatial learning and memory. We investigated the effect of HT on synaptic transmission and high-frequency stimulation-induced LTP in the Schaffer collateral-CA1 synapse of mice hippocampus in vivo. Then, animals were sacrificed for thyroid-related parameter measure as well as detection of cellular and molecular events associated with the induction of LTP. Results: HT mice showed intrathyroidal lymphocyte infiltration and rising serum thyroid autoantibody levels accompanied by normal thyroid function. The HT mice had poorer performance in Morris water maze than controls. These alterations were mirrored by abnormalities in synaptic plasticity in the Schaffer collateral-CA1 synapses of the hippocampus in vivo. The integrity of the synaptic structure is the premise for the production of LTP. As detected by transmission electron microscopy, the ultrastructure of synapse and astrocyte in the hippocampus were impaired in euthyroid HT mice. Additionally, Western blot and real-time polymerase chain reaction analyses confirmed that in HT mice, GS, GLAST, and GLT-1, key elements in glutamate-glutamine circulation located in astrocyte, were downregulated, accompanied by elevated levels of glutamate in the hippocampus, which impaired the material basis for LTP induction. NMDR2B expression in the hippocampus was also downregulated. Conclusion: HT can induce damage of LTP in the hippocampal Schaffer collateral-CA1 pathway in the euthyroid state, and this can be attributed, at least partly, to astrocytes impairment, which may underlie the deleterious effects of HT itself on hippocampal-dependent learning and memory function.

Hashimoto's thyroiditis impairs embryo implantation by compromising endometrial morphology and receptivity markers in euthyroid mice

BACKGROUND

Although thyroid dysfunction caused by Hashimoto's thyroiditis (HT) is believed to be related to implantation failure due to the underdevelopment of the receptive uterus, it is unknown whether HT itself, even in the euthyroid state, impairs embryo implantation associated with endometrial receptivity defects. To address whether HT itself can affect endometrial receptivity accompanied by implantation alterations, a euthyroid HT model was established in mice.

METHODS

Female NOD mice were immunized twice with thyroglobulin and adjuvant to induce the experimental HT model. Four weeks after the second treatment, the mice were normally mated, and pregnant ones were sacrificed in implantation window for thyroid-related parameter and steroid hormones measurements by electrochemiluminescence immunoassay and enzyme-linked immunosorbent assay and implantation site number calculation by uptake of Chicago Blue dye. In addition, certain morphological features of endometrial receptivity were observed by hematoxylin-eosin staining and scanning electron microscopy, and the expression of other receptivity markers were analyzed by immunohistochemistry, RT-qPCR or Western Blot.

RESULTS

HT mice displayed intrathyroidal monocyte infiltration and elevated serum thyroid autoantibody levels without thyroid dysfunction, defined as euthyroid HT in humans. Euthyroid HT resulted in implantation failure, fewer pinopodes, retarded pinopode maturation, and inhibited expression of receptivity markers: estrogen receptor α (ERα), integrin β3, leukemia inhibitory factor (LIF), and cell adhesion molecule-1 (ICAM-1). Interestingly, despite this compromised endometrial receptivity response, no statistical differences in serum estradiol or progesterone level between groups were found.

CONCLUSIONS

These findings are the first to indicate that HT induces a nonreceptive endometrial milieu in the euthyroid state, which may underlie the detrimental effects of HT itself on embryo implantation.

Hashimoto's thyroiditis induces neuroinflammation and emotional alterations in euthyroid mice

Background

Although studies have reported an increased risk for mood disorders in Hashimoto’s thyroiditis (HT) patients even in the euthyroid state, the mechanisms involved remain unclear. Neuroinflammation may play a key role in the etiology of mood disorders in humans and behavioral disturbances in rodents. Therefore, this study established a euthyroid HT model in mice and investigated whether HT itself was capable of triggering neuroinflammation accompanied by emotional alterations.

Methods

Experimental HT was induced by immunizing NOD mice with thyroglobulin and adjuvant twice. Four weeks after the last challenge, mice were tested for anxiety-like behavior in the open field and elevated plus maze tests and depression-like behavior in the forced swimming and tail suspension tests. Then, animals were sacrificed for thyroid-related parameter measure as well as detection of cellular and molecular events associated with neuroinflammation. The changes in components of central serotonin signaling were also investigated.

Results

HT mice showed intrathyroidal monocyte infiltration and rising serum thyroid autoantibody levels accompanied by normal thyroid function, which defines euthyroid HT in humans. These mice displayed more anxiety- and depressive-like behaviors than controls. HT mice further showed microglia and astrocyte activation in the frontal cortex detected by immunohistochemistry, real-time RT-PCR, and transmission electron microscopy (TEM). These observations were also accompanied by enhanced gene expression of proinflammatory cytokines IL-1β and TNF-α in the frontal cortex. Despite this inflammatory response, no signs of neuronal apoptosis were visible by the TUNEL staining and TEM in the frontal cortex of HT mice. Additionally, IDO1 and SERT, key serotonin-system-related genes activated by proinflammatory cytokines, were upregulated in HT mice, accompanied by reduced frontal cortex serotonin levels.

Conclusions

Our results are the first to suggest that HT induces neuroinflammation and alters related serotonin signaling in the euthyroid state, which may underlie the deleterious effects of HT itself on emotional function.

Single Point Mutations in Pediatric Differentiated Thyroid Cancer

PURPOSE

Differentiated thyroid cancer (DTC) is rare in children. Previous studies have suggested that it has different clinicopathologic features and mutation profiles compared with adult DTC. However, those studies focused on a single or limited number of gene mutations. This study comprehensively investigated a large series of pediatric DTC for single point mutations in BRAF, HRAS, KRAS, NRAS, PIK3CA, PTEN, and TERT. It also analyzed associations between clinicopathologic features and the BRAF^V600E mutation.

PATIENTS AND METHODS

Eighty-nine consecutive cases seen in children and adolescents (≤18 years) during 1998-2015 were identified. Rare variants of DTC were excluded, and the study focused on 72 (91.1%) classical papillary thyroid carcinoma (PTC) and seven (8.9%) follicular variant PTC. These included 68 (86.1%) females and 11 (13.9%) males, with a median age of 15.5 years (range 8-18 years). The clinical and histopathological data were obtained from medical records. DNA was extracted from paraffin-embedded tumor tissue, and was PCR-amplified and directly sequenced.

RESULTS

Mutations detected included BRAF^V600E in 19/72 (26.4%) classical PTC samples, and in none of seven follicular variant PTC. Other mutations included: 1/78 (1.3%) successfully amplified tumor samples with TERT^C228T; 2/79 (2.5%) NRAS 61 (c.181C>A and c.182A>G); 1/73 (1.4%) PIK3CA exon 9 (c.1589A>G and c.1598C>T in one tumor); 1/79 (1.3%) PIK3CA exon 20 (c.2951G>A); and 1/74 (1.4%) PTEN exon 5 (c.295G>A). No mutation was found in HRAS, KRAS, NRAS12, PTEN exons 6, 7, and 8, and TERT^C250T. No significant association was found between BRAF^V600E mutation and sex, extrathyroidal invasion, tumor multifocality, vascular invasion, lymph node or distant metastases, and persistent/recurrent disease.

CONCLUSIONS

In pediatric DTC, the prevalence of the BRAF^V600E mutation is significantly less common compared with adult DTC, and there is no association between this mutation and the histopathological features and outcome of PTC. PIK3CA, PTEN, NRAS 61, and TERT^C228T mutations are rare.

Thyroid nodules and thyroid autoimmunity in the context of environmental pollution

Evidence suggests that in most industrialized countries autoimmune disorders, including chronic lymphocytic thyroiditis, are increasing. This increase parallels the one regarding differentiated thyroid cancer, the increment of which is mainly due to the papillary histotype. A number of studies have pointed to an association between chronic lymphocytic thyroiditis and differentiated thyroid cancer. The upward trend of these two thyroid diseases is sustained by certain environmental factors, such as polluting substances acting as endocrine disrupting chemicals. Herein we will review the experimental and clinical literature that highlights the effects of environmental and occupational exposure to polluting chemicals in the development of autoimmune thyroid disease or differentiated thyroid cancer. Stakeholders, starting from policymarkers, should become more sensitive to the consequences for the thyroid resulting from exposure to EDC. Indeed, the economic burden resulting from such consequences has not been quantified thus far.

Association of Hashimoto's thyroiditis with cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and inducible co-stimulator (ICOS) genes in a Kuwaiti population

Analysing two CTLA-4 markers [exon 1 A49G single nucleotide polymorphism (SNP) and exon 4 3'UTR (AT)n repeat] and the ICOS intron 4 (GT)n marker for their potential association with HT, and exploring the effect of the tested SNPs on the CTLA-4 isoform expression at the mRNA and protein levels. Total of 270 age-gender-ethnically matched subjects were genotyped by fluorescent-labelled restriction fragment length polymorphism, multiplex PCR, and fragment analysis. Sequencing was used to confirm the genotyping results. Expression of the full-length and soluble CTLA-4 mRNAs analysed using real-time PCR. Sera from subjects were screened for sCTLA-4 using ELISA. Tested subjects revealed ten alleles and sixteen genotypes of CTLA-4 3'UTR(AT)n. The 3'UTR(AT)n was significantly associated with HT: allele (AT)15 and genotype 15/15 were found to cause susceptibility to HT (P = 0.004, OR = 2.13, 95 % CI = 1.26-3.58 and P = 0.029, OR = 2.77, 95 % CI = 1.1-6.94, respectively), whereas allele (AT)6 and genotype 6/6 were found to be protective of HT (P = 0.00002, OR = 0.36, 95 % CI = 0.227-0.57 and P = 0.001, OR = 0.357, 95 % CI = 0.1980.64, respectively). SNP A49G and ICOS(GT)n revealed no significant association with HT (P > 0.05). The expression of sCTLA-4 was inversely proportional to the number of 3'UTR(AT)n repeats, with heterozygous and longer (AT)n repeats showing lower levels of sCTLA-4 mRNA than those with shorter alleles in HC and HT (P = 0.001 and P = 0.04, respectively). Significant increase in the serum level of sCTLA-4 was observed in HT patients compared with the HC (P = 0.0007). The novel finding in our study is that the CTLA-4 3'UTR(AT)n proven to be a key player in the pathogenesis of HT.

Surgical Indications for Goiter with Background Hashimoto's Thyroiditis: Institutional Experience

Hashimoto's thyroiditis (HT) is usually treated conservatively with thyroxine. Its incidence is higher in Iodine sufficient areas and may require surgery for associated nodularity or complications. A retrospective study on surgically treated HT cases was conducted in a teritiary care teaching hospital in an Iodine sufficient area of Southern India. 34 cases of goiter with associated HT, who underwent thyroidectomy between 2007 and 2010 were analysed for indications of surgery. Minimum follow-up period was 6 months. F:M ratio was 31:3 with mean age of 41.3 years. Goiter was diffuse in 41% and nodular in 59%. 16 (47%) of patients were hypothyroid. Autoimmune association was found in 35%. Commonest surgery done was hemithyroidectomy in 12 (35%) followed by subtotal thyroidectomy in 10 cases. Most frequent indication for surgery was nodular goiter in 12 (35%) followed by associated malignancy, persistent goiter, pressure symptoms and painful thyroiditis. Histopathology showed diffuse HT alone in 12 (35%) and rest of the cases had HT as a component synchronous with other pathologies. Associated pathologies were benign multinodular goiter (6), colloid nodule (6), papillary cancer (5), follicular adenoma (4), cyst (1). Surgery for HT is primarily indicated for associated pathologies like dominant nodule, suspicious or proven malignancy, persistent goiter, painful thyroiditis, pressure symptoms and rarely for HT perse. Rate of surgery for HT associated goiter appears to be higher in Iodine sufficient areas, the cause of which needs to be studied further.

Increased annual frequency of Hashimoto's thyroiditis between years 1988 and 2007 at a cytological unit of Sicily

Like other auto-immune diseases, Hashimoto's thyroiditis (HT) results from the interaction of genetic with environmental factors. Only few studies have evaluated the year-to-year change in frequency of HT over a wide period of time. The endocrine division of our Hospital has reported a great increase in the annual frequency of HT between 1975 and 2005, and a progressive decrease in both age at presentation and female to male (F/M) ratio starting in the mid-1990s. Between years 1988 and 2007, we have collected 8397 adequate examinations by fine needle aspiration cytology (FNAC) on 8397 persons referred for the evaluation of a solitary or dominant thyroid nodule (total FNAC and persons=8520) with a 14-fold increase in 2007 over 1988. In this 20-year period, cases of HT, De Quervain's thyroiditis (DQT) and Riedel's thyroiditis (RT) were 490, 36 and two, respectively. HT cases were one in 1988 but 90 in 2007, with a significant upward temporal trend (r=0.919, P<0.001) and significant downward trend for age at FNAC (r=-0.466, P<0.05). In contrast, DQT cases were zero and one, respectively, with no significant temporal trend (r=0.29, P=0.21). The HT increase in frequency started in 1996 (+350% over 1995). Until 1995 there was only one man, but there were 22 men in 2005-2007. These FNAC data provide independent confirmation to the data from the endocrine division of the same hospital, further supporting the conclusion that only environmental modifications can explain these marked changes that have occurred in such a relatively short period of time.

Changed presentation of Hashimoto's thyroiditis in North-Eastern Sicily and Calabria (Southern Italy) based on a 31-year experience

OBJECTIVE

To quantify the yearly prevalence of Hashimoto's thyroiditis at our Division and evaluate changes in its clinical presentation over the period 1975-2005.

DESIGN

We have reviewed retrospectively the clinical records of patients admitted to a university hospital located in Messina, Sicily (Italy), from January 1, 1975, through December 31, 2005. This facility attracts patients from North-Eastern Sicily and most of Calabria, the Italian region across the Straits. HT was diagnosed based on various combinations of clinical, laboratory, and instrumental findings. The study group consisted of 4064 HT patients diagnosed during these 31 years.

MAIN OUTCOME

We evaluated these indexes on a yearly basis: number of new HT diagnoses; age at presentation; male-to-female ratio; functional status; goitrous or nongoitrous variants with or without nodule(s); above-normal titers or levels of serum thyroid autoantibodies (thyroglobulin antibodies and thyroperoxidase antibodies). Several indexes have changed over those 31 years. Particularly, HT has become 10 times more common than it was until the early 1990s and males are relatively more represented. Patients are relatively younger, with a nongoitrous thyroid; the rate of S-Hypo exceeds largely the rate of O-Hypo. Serum thyroid autoantibodies have become less frequently positive, and when positive, they are present at a lower concentration.

CONCLUSIONS

Only environmental changes, as opposed to genetic changes, can account for such alterations in the presentation of HT in our geographical area.