Thyroid®

Untreated adult hypothyroidism may be associated with cognitive and emotional impairment, but the precise underlying neuropathological mechanism is unknown. We investigated the brain morphological and functional abnormalities associated with cognition and emotion in hypothyroidism.

This is a cross-sectional observational study. Forty-four newly diagnosed adult hypothyroid patients and 54 well-matched healthy controls (HCs) were enrolled. All participants underwent three-dimensional T1-weighted imaging and resting-state functional magnetic resonance imaging (MRI). Morphological and seed-based functional connectivity (FC) analyses were performed to compare the intergroup differences. Neuropsychological tests, including the Montreal Cognitive Assessment (MoCA) Scale, 24-item Hamilton Depression Rating Scale (HAMD-24), and Hamilton Anxiety Rating Scale (HAMA) were administered. Thyroid function test and blood lipid levels were measured. Correlations were computed between neuropsychological and biochemical measures with neuroimaging indices. Sensitive morphological or functional neuroimaging indicators were identified using receiver operating characteristic (ROC) analysis.

Compared with HCs, hypothyroid patients demonstrated lower total and subdomain scores on the MoCA and higher HAMD-24 and HAMA scores. Morphological analysis revealed the hypothyroid patients had significantly reduced gray matter (GM) volumes in the right superior frontal gyrus, superior temporal gyrus, left dorsolateral superior frontal gyrus, middle frontal gyrus, and supplementary motor area as well as significantly increased GM volumes in the bilateral cerebellar Crus I and left precentral gyrus. Furthermore, seed-based FC analysis of hypothyroid patients showed increased FC between the right cerebellar Crus I and left precentral gyrus, triangular part of the inferior frontal gyrus, and angular gyrus of the inferior parietal lobe. The language scores of the MoCA were positively correlated with Jacobian values of the left supplementary motor area (r = 0.391, p = 0.046) and precentral gyrus (r = 0.401, p = 0.039). ROC analysis revealed FC value between cerebellar Crus I and angular gyrus could differentiate groups with relatively high accuracy (sensitivity: 75%, specificity: 77.8%, area under the curve: 0.794 [CI 0.701–0.888], p < 0.001).

Untreated adult-onset hypothyroidism may be associated with impaired cognition and anxiety or depression. GM morphological alterations and FC of the cerebellum with subregions of the frontal and parietal lobes may represent key neuropathological mechanisms underlying the cognitive deterioration and mood dysregulation observed in hypothyroid adults. Clinical Trial Registration Number: chiCTR2000028966.

Antithyroid drugs (ATDs) are frequently used to achieve euthyroidism in patients with hyperthyroidism. ATDs cause characteristic common and rare adverse events; however, comprehensive comparisons between methimazole (MMI) and propylthiouracil (PTU) in terms of adverse events are limited.

In this study, we thoroughly explored adverse events in association with MMI and PTU use with a disproportionality analysis using the Japanese Adverse Drug Event Report (JADER) database and evaluated the prevalence of MMI and PTU prescriptions using the National Database of Health Insurance Claims and Specific Health Checkups (NDB) Open Data Japan. We analyzed 3271 cases of MMI use and 1029 cases of PTU use with respect to 9789 preferred terms (PTs) for adverse events registered in the JADER database by calculating and comparing reporting odds ratios (RORs).

We found that 8 PTs, including agranulocytosis (p < 0.0001, 4.01-fold), aplasia cutis congenita (p < 0.0001, 123.22-fold), and exomphalos (p = 0.0002, 22.17-fold), demonstrated significantly higher RORs (more than 4-fold) for MMI use than for PTU use. Nineteen PTs, including anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (p < 0.0001, 29.84), rapidly progressive glomerulonephritis (p < 0.0001, 6.44), and pulmonary alveolar hemorrhage (p < 0.0001, 7.77), had RORs for PTU use more than four times those for MMI use. NDB Open Data Japan showed more frequent PTU prescriptions than MMI prescriptions for women of reproductive age.

This large-scale study confirmed that a variety of congenital malformations were identified as having significantly high RORs for MMI use, while diseases related to ANCA-associated vasculitis were specific to PTU.

It has been 30 years since the initiation of active surveillance (AS) for adult patients with low-risk papillary thyroid microcarcinoma (PTMC). This study compared the long-term oncological outcomes of patients who underwent AS or immediate surgery (IS).

This is a retrospective review of extended follow-up data from patients enrolled in a single-center, prospective observational study in Japan. In total, 5646 patients diagnosed with low-risk PTMC at Kuma Hospital between 1993 and 2019 were enrolled in this study. Of these, 3222 patients underwent AS (AS group), whereas 2424 underwent IS (IS group). The patients were followed up regularly, at least once per year. Descriptive outcome data were presented according to the treatment group.

In the AS group, 124 patients (3.8%) had tumor enlargement of ≥3 mm, and the 10- and 20-year enlargement rates were 4.7% and 6.6%, respectively. Novel lymph node metastases occurred in 27 patients (0.8%), and the 10- and 20-year nodal metastasis occurrence rates were 1.0% and 1.6%, respectively. In the IS group, 13 patients (0.5%) experienced lymph node recurrence postoperatively, and the 10- and 20-year nodal recurrence rates were 0.4% and 0.7%, respectively. Eighteen (1.4%) of the 1327 patients who underwent hemithyroidectomy experienced recurrence in the residual thyroid. The rate of lymph node metastasis was significantly higher in the AS group than in the IS group (1.1% vs. 0.4% and 1.7% vs. 0.7% at 10 and 20 years, respectively; p = 0.009), but the differences were small. However, the proportion of patients who underwent one or more and two or more surgeries was significantly higher in the IS group than in the AS group (100% vs. 12.3% and 1.07% vs. 0.09%, p < 0.01). Distant metastatic recurrence was observed in one patient after AS and conversion surgery and another after IS; however, they were alive (18.4 and 18.8 years after diagnosis, respectively). None of the patients in this study died of thyroid carcinoma.

Long-term oncological outcomes of patients with PTMC generally did not differ clinically significantly between those undergoing AS and IS. AS is a viable initial management option for patients with low-risk PTMC.

Internationally, several clinical practice guidelines recommend active surveillance as a nonsurgical management strategy for select patients with low-risk papillary thyroid carcinoma. However, patient's decision making when choosing active surveillance as a management approach is not well understood. Thus, our aim was to examine the barriers and facilitators to selecting active surveillance among patients with low-risk papillary thyroid carcinoma in China.

Thirty-nine participants diagnosed with low-risk papillary thyroid carcinoma were purposively recruited between July and November 2021 for semistructured interviews; 24 of whom rejected and 15 patients chose “active surveillance” as a management approach in our sample. Inductive content analysis illustrated emerging themes. Audit trails, member checks, and thematic discussions were used to assert rigor.

Barriers and facilitators were classified as patient-related, disease-related, and external factors. Patient-related factors included patient's knowledge, attitudes, and emotions. Disease-related factors included the response to having cancer, the constant state of being diseased, and perceived value of the thyroid gland. External factors included the residual effects of surgery, the active surveillance protocol, and physicians' recommendations.

Patient's acceptability of the active surveillance as a management approach are complex with many influencing factors. The public acceptance of active surveillance as a disease management approach needs to be improved, through the presentation of active surveillance as an evidence-based and optimized dynamic management strategy. Clinicians must address their patients' psychological struggles when patients choose active surveillance and patients require more attention and supportive intervention.

Anaplastic thyroid carcinoma (ATC) is a rapidly fatal cancer with a median survival of a few months. Enhanced therapeutic options for durable management of ATC will rely on an understanding of genetics and the role of the tumor microenvironment. The prognosis for patients with ATC has not improved despite more detailed scrutiny of underlying tumor genetics. Pericytes in the microenvironment play a key evasive role for thyroid carcinoma (TC) cells. Lenvatinib improves outcomes in patients with radioiodine-refractory well-differentiated TC. In addition to the unclear role of pericytes in ATC, the effect and mechanism of lenvatinib efficacy on ATC have not been sufficiently elucidated.

We assessed pericyte enrichment in ATC. We determined the effect of lenvatinib on ATC cell growth cocultured with pericytes and in a xenograft mouse model from human BRAF^WT/V600E -ATC-derived cells coimplanted with pericytes.

ATC samples were significantly enriched in pericytes compared with normal thyroid samples. BRAF^WT/V600E -ATC-derived cells were resistant to lenvatinib treatment shown by a lack of suppression of MAPK and Akt pathways. Moreover, lenvatinib increased CD47 protein (thrombospondin-1 [TSP-1] receptor) levels over time vs. vehicle. TSP-1 levels were downregulated upon lenvatinib at late vs. early time points. Critically, ATC cells, when cocultured with pericytes, showed increased sensitivity to this therapy and ultimately decreased number of cells. The coimplantation in vivo of ATC cells with pericytes increased ATC growth and did not downregulate TSP-1 in the microenvironment in vivo.

Pericytes are enriched in ATC samples. Lenvatinib showed inhibitory effects on BRAF^WT/V600E -ATC cells in the presence of pericytes. The presence of pericytes could be crucial for effective lenvatinib treatment in patients with ATC. Degree of pericyte abundance may be an attractive prognostic marker in assessing pharmacotherapeutic options. Effective durable management of ATC will rely on an understanding not only of genetics but also on the role of the tumor microenvironment.

The 2015 American Thyroid Association (ATA) guidelines shifted recommendations toward less aggressive management of papillary thyroid cancer (PTC). Subsequently, several studies demonstrated a trend in performing thyroid lobectomy (TL) over total thyroidectomy (TT). However, regional variation has persisted without a clear indication of what factors may be influencing practice variation. We aimed to evaluate the surgical management of PTC in patients in rural and urban settings to assess trends of TL compared with TT following the implementation of the 2015 ATA guidelines.

A retrospective cohort analysis was performed using the Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2019 of patients with localized PTC <4 cm who underwent TT or TL. Patients were classified as living in urban or rural counties based on the 2013 Rural-Urban Continuum Codes. Procedures performed from 2004 to 2015 were categorized as preguidelines, while those performed from 2016 to 2019 were categorized as postguidelines. Chi-square, Student's t-test, logistic regression, and Cochran–Mantel–Haenszel test were used.

A total of 89,294 cases were included in the study. Eighty thousand one hundred and fifty (89.8%) were from urban settings and 9144 (9.2%) were from rural settings. Patients from rural settings were older (52 vs. 50 years, p < 0.001) and had smaller nodules (p < 0.001). On adjusted analysis, patients in rural areas were less likely to undergo TT (adjusted odds ratio 0.81, confidence interval [CI] 0.76–0.87). Before the 2015 guidelines, patients in urban settings had a 24% higher odds of undergoing TT compared with those in rural settings (odds ratio 1.24, CI 1.16–1.32, p < 0.001). There was no difference in the proportions of TT and TL based on setting following guideline implementation (p = 0.185).

The 2015 ATA guidelines led to a change in overall practice in surgical management of PTC toward increasing TL. While urban and rural practice variation existed before 2015, both settings had an increase in TL following the guideline change, emphasizing the importance of clinical practice guidelines to ensure best practice in both rural and urban settings.

We aimed to assess the long-term effects of the transition in iodine status on the incidence of thyroid disorders over 20 years of follow-up.

The original prospective cohort study, started in 1999 (n = 3761), classified three regions in north China based on iodine status (insufficient iodine, more than adequate iodine, and excessive iodine, respectively) for 5 years. Subsequently, participants were followed for up to another 15 years to assess the long-term effects of shifts to adequate iodine on the incidence of thyroid disorders. Panshan transitioned from insufficient to adequate iodine, and Huanghua transitioned from excessive to more than adequate iodine. Both regions were compared with Zhangwu, in which iodine status changed from more than adequate to adequate iodine (from 214 to 167.2 μg/L). A cluster sampling method was used to select participants in the three regions. Participants completed questionnaires and underwent thyroid ultrasonography. Urinary iodine concentrations (UICs), serum thyroid hormone concentration, and thyroid antibodies were measured.

When the iodine status changed from insufficient to adequate (with the median UIC increasing from 88 to 141.9 μg/L), the incidence density of subclinical hyperthyroidism, positive thyroperoxidase antibody, positive thyroglobulin antibody (TgAb), and goiter decreased significantly (p < 0.05 for all). Additionally, the cumulative incidence of subclinical hypothyroidism was significantly lower compared with the region where the iodine status changed from being more than adequate to adequate (1.9% vs. 6.0%, p < 0.001). When the iodine status changed from excessive to more than adequate (median UIC from 634 to 266.7 μg/L), a significant decrease in the incidence density of subclinical hyperthyroidism, positive thyroid antibodies, positive TgAb, and goiter (p < 0.05 for all) were also found. However, an increase in thyroid nodule incidence density (17.26 vs. 28.25 per 1000 person-years, p < 0.001) was seen.

The incidence of thyroid disorders (except for thyroid nodules) stabilized or decreased among adults in the three communities from year 5 to year 15 of follow-up. Appropriate iodine fortification is safe and effective over the long term. Restoring urinary iodine to appropriate levels reduces population risk for thyroid disorders.

Thyrotropin-releasing hormone (TRH) neurons in the paraventricular nucleus of the hypothalamus (PVN) have been identified as direct regulators of thyrotropin (TSH) and thyroid hormone (TH) levels. They play a significant role in context of negative feedback by TH at the level of TRH gene expression and during fasting when TH levels fall due, in part, to suppression of TRH gene expression.

To test these functions directly for the first time, we used a chemogenetic approach and activated PVN TRH neurons in both fed and fasted mice. Next, to demonstrate the signals that regulate the fasting response in TRH neurons, we activated or inhibited agouti-related protein (AgRP)/neuropeptide Y (NPY) neurons in the arcuate nucleus of the hypothalamus of fed or fasted mice, respectively. To determine if the same TRH neurons responsive to melanocortin signaling mediate negative feedback by TH, we disrupted the thyroid hormone receptor beta (TRβ) in all melanocortin 4 receptor (MC4R) neurons in the PVN.

Activation of TRH neurons led to increased TSH and TH levels within 2 hours demonstrating the specific role of PVN TRH neurons in the regulation of the hypothalamic–pituitary–thyroid (HPT) axis. Moreover, activation of PVN TRH neurons prevented the fall in TH levels in fasting mice. Stimulation of AgRP/NPY neurons led to a fall in TH levels despite increasing feeding. Inhibition of these same neurons prevented the fall in TH levels during a fast presumably via their ability to directly regulate PVN TRH neurons via, in part, the MC4R. Surprisingly, TH-mediated feedback was not impaired in mice lacking TRβ in MC4R neurons.

TRH neurons are major regulators of the HPT axis and the fasting-induced suppression of TH levels. The latter relies, at least in part, on the activation of AgRP/NPY neurons in the arcuate nucleus. Interestingly, present data do not support an important role for TRβ signaling in regulating MC4R neurons in the PVN. Thus, it remains possible that different subsets of TRH neurons in the PVN mediate responses to energy balance and to TH feedback.