Levothyroxine therapy, calculated deiodinases activity and basal metabolic rate in obese or nonobese patients after total thyroidectomy for differentiated thyroid cancer, results of a retrospective observational study.

INTRODUCTION: Therapy for hypothyroid obese patients is still under definition since the thyrotropin-stimulating hormone (TSH) level is a less reliable marker of euthyroidism than nonobese patients. Indeed, TSH levels positively correlate with body mass index (BMI), and this increase may be a compensatory mechanism aimed at increasing energy expenditure in obese people. In contrast, the correlation of BMI with thyroid hormone levels is not completely clear, and conflicting results have been obtained by several studies. The L-T4 replacement dose is more variable in obese hypothyroid patients than in nonobese patients, and a recent study indicated that the L-T4 replacement dose is related to lean body mass in obese thyroidectomized patients. We aimed to study the correlations of L-T4-administered dose, thyroid hormone levels and TSH secretion with basal metabolic rate (BMR) and total calculated deiodinase activity (GD) in obese and nonobese athyreotic patients. We also looked for individualized L-T4 replacement dose set points to be used in clinical practice. METHODS: We studied retrospectively 160 athyreotic patients, 120 nonobese and 40 obese. GD was calculated by SPINA Thyr 4.2, the responsiveness of the hypothalamic/pituitary thyrotrope by Jostel's thyrotropin (TSH) index and BMR by the Mifflin-St. Jeor formula, the interplay of GD and BMR with L-T4, thyroid hormones and TSH index (TSHI) was also evaluated. RESULTS: In our study, the L-T4 dose was an independent predictor of GD, and approximately 30% of athyreotic patients under L-T4 therapy had a reduced GD; FT4 levels were higher and negatively modulated by BMR in obese athyreotic patients respect to nonobese, in these patients a T4 to T3 shunt, in terms of TSHI suppression is observed suggesting a defective hypothalamic pituitary T4 to T3 conversion and a resistance to L-T4 replacement therapy. CONCLUSIONS: L-t4 dose is the most important predictor of GD, BMR modulates T4 levels in obese athyreotic patients that are resistant to L-T4 replacement therapy.

Discovery of AZD4831, a Mechanism-Based Irreversible Inhibitor of Myeloperoxidase, As a Potential Treatment for Heart Failure with Preserved Ejection Fraction.

Myeloperoxidase is a promising therapeutic target for treatment of patients suffering from heart failure with preserved ejection fraction (HFpEF). We aimed to discover a covalent myeloperoxidase inhibitor with high selectivity for myeloperoxidase over thyroid peroxidase, limited penetration of the blood-brain barrier, and pharmacokinetics suitable for once-daily oral administration at low dose. Structure-activity relationship, biophysical, and structural studies led to prioritization of four compounds for in-depth safety and pharmacokinetic studies in animal models. One compound (AZD4831) progressed to clinical studies on grounds of high potency (IC50, 1.5 nM in vitro) and selectivity (>450-fold vs thyroid peroxidase in vitro), the mechanism of irreversible inhibition, and the safety profile. Following phase 1 studies in healthy volunteers and a phase 2a study in patients with HFpEF, a phase 2b/3 efficacy study of AZD4831 in patients with HFpEF started in 2021.

The description of neuromyelitis optica spectrum disorder: Patient registry in Yangtze River Delta area of China.

OBJECTIVE: To describe the clinical features of neuromyelitis optica spectrum disorder (NMOSD) through patient registry in Yangtze River Delta area of China. METHODS: A total of 502 consecutive patients diagnosed with aquaporin-4 antibody (AQP4-ab)-positive NMOSD were registered between December 2018 to January 2021 in multiple tertiary referral centers within the framework of Yangtze River Delta of China. Their baseline data were reviewed, and follow-up clinical information were collected prospectively. RESULTS: The mean age at onset was 37.3 (range 3-80 years) years and the female-to-male ratio was 8.1:1. The median disease duration was 47 months (interquartile range [IQR] 25-84 months). A total of 1372 attacks of the 502 patients were recorded till the last follow-up, with a median annualized relapse rate of 0.4 (IQR 0.3-0.6). Nearly one-fourth (24.5%, 336/1372) of the attacks had prodromic events, including upper respiratory tract infection (36.3%, 122/336), fever (20.2%, 68/336) and pregnancy-related issues (17.9%, 60/336), etc. Myelitis was the most common attack type throughout the disease course (51.4%, 705/1372), followed by optic neuritis (ON, 43.1%, 592/1372). As for onset phenotype, ON (37.3%, 187/502) prevailed over myelitis (28.3%, 142/502). The median time to first relapse was 12 months (IQR 5-25 months). Patients with brainstem encephalitis at onset were more likely to have other anatomical region involved in subsequent attacks (p < 0.001), compared to other onset type. The median serum AQP4-ab titer measured by cell-based assays was 1:100 (IQR 1:32-1:320, range 1:10-1:10,000). The baseline AQP4-ab titer in cerebrospinal fluid (r = 0.542, p <0.001), overall ARR (r = 0.232, p< 0.001) and the EDSS scores at last follow-up (r = 0.119, p = 0.022) significantly correlated with baseline serum AQP4-ab titer. Antinuclear antibodies (48.4%), thyroid peroxidase antibodies (30.7%), and anti-SSA antibodies (26.2%) represented the most frequent concomitant antibodies, while autoimmune thyroid disorders (13.1%, 66/502) and Sjogren's syndrome (10.8%, 54/502) were the most common accompanying autoimmune diseases. Till the last follow-up, 403 patients received preventive treatments. Azathioprine represented the most common initial treatment, mycophenolate mofetil and rituximab was the most common second and third-line treatment, respectively. The EDSS score at the last follow-up ranged from 0 to 8.5 with a median of 2 (IQR 1-3). CONCLUSIONS: A comprehensive clinical picture of patients with AQP4-ab-positive NMOSD in Yangtze River Delta area of China was presented. More information on disease tragedy and predictive prognostic factors could be generated through long-term observations.

Association between thyroid autoimmunity and antidepressant treatment-emergent mania in pediatric mood disorders.

Risk factors associated with antidepressant treatment-emergent mania(ATEM) are poorly characterized in child and adolescent populations. To identify better biomarkers, we aimed to explore whether thyroid autoimmunity is associated with ATEM in pediatric mood disorders. We enrolled two groups of pediatric mood disorders, those with ATEM+ (n = 29) and those with ATEM- controls (n = 31). All diagnoses were made according to structured interviews by the clinicians. Autoimmune thyroiditis (anti-thyroid peroxidase antibodies [TPO-abs] and thyroid function (thyroid-stimulating hormone [TSH] and free thyroxin [FT4]) were assessed. Logistic regression was used to explore the relationship between TPO-abs seroprevalence and ATEM+ while controlling for covariates. Group comparisons showed that the patient with ATEM+ had significantly higher seroprevalence and titer of TPO-abs compared to ATEM- controls. In logistic regression analysis adjusting for age, gender, Tanner stage, body mass index, antipsychotic treatments, smoking status and family history of thyroid disorder, the seroprevalence of TPO-abs (>60 U/mL) was significantly associated with ATEM+ (OR = 3.67, 95% confidence interval [CI] = 1.2-11.1, p = 0.022). Our findings demonstrated that seroprevalence and titer of TPO-abs in pediatric mood disorders are associated with ATEM+ status. TPO-abs could potentially serve as a biomarker when assessing the risk of ATEM in the child and adolescent population.

Liothyronine use in primary hypothyroidism - current concepts.

Hypothyroidism is an endocrine disorder whose management raises many challenges in clinical practice. Its standard treatment is levothyroxine (LT4). The goal of the treatment is to normalize signs and symptoms, as well as to achieve thyroid-stimulating hormone (TSH) concentrations within the reference range, on an individual basis. It is known that 5-10% of hypothyroid patients remain symptomatic, despite achieving the target TSH levels, which, in turn, affects their quality of life. After ruling out other causes of non-thyroid origin for this persistence, it is suggested that these patients could benefit from the use of liothyronine (LT3), added to LT4, especially if polymorphism of the deiodinase 2 (D2) genes is documented. There exist a variety of LT3 preparations, whose concentrations vary from 5 to 50 ug, with the recommended LT4/LT3 ratio of 13:1-20:1. The goals of combination therapy should be to achieve a physiological ratio of free triiodothyronine/free thyroxine (FT3/FT4) and non-suppression of TSH. Because there is currently no guide that makes evidence-based recommendations on the use of LT3 in primary hypothyroidism, more clinical studies are needed to be able to identify hypothyroid patients who may benefit from the use of LT3, by identifying new biomarkers.

Deiodinases and their intricate role in thyroid hormone homeostasis.

The deiodinase family of enzymes mediates the activation and inactivation of thyroid hormone. The role of these enzymes in the regulation of the systemic concentrations of thyroid hormone is well established and underpins the treatment of common thyroid diseases. Interest in this field has increased in the past 10 years as the deiodinases became implicated in tissue development and homeostasis, as well as in the pathogenesis of a wide range of human diseases. Three deiodinases have been identified, namely, types 1, 2 and 3 iodothyronine deiodinases, which differ in their catalytic properties and tissue distribution. Notably, the expression of these enzymes changes during the lifetime of an individual in relation to the different needs of each organ and to ageing. The systemic homeostatic role of deiodinases clearly emerges during changes in serum concentrations of thyroid hormone, as seen in patients with thyroid dysfunction. By contrast, the role of deiodinases at the tissue level allows thyroid hormone signalling to be finely tuned within a given cell in a precise time-space window without perturbing serum concentrations of thyroid hormone. This Review maps the overall functional role of the deiodinases and explores challenges and novel opportunities arising from the expanding knowledge of these 'master' components of the thyroid homeostatic system.

Overexpression of Type 3 Iodothyronine Deiodinase Reduces Cone Death in the Leber Congenital Amaurosis Model Mice.

Leber congenital amaurosis (LCA) is a devastating pediatric retinal degenerative disease, accounting for 20% of blindness in children attending schools for the blind. Mutations in the RPE65 gene, which encodes the retinal pigment epithelium-specific isomerohydrolase RPE65, account for 16% of all LCA cases. Recent findings have linked cone photoreceptor viability to thyroid hormone (TH) signaling. TH signaling regulates cell proliferation, differentiation, and metabolism. At the cellular level, TH action is regulated by the two iodothyronine deiodinases, DIO2 and DIO3. DIO2 converts the prohormone thyroxine (T4) to the bioactive hormone triiodothyronine (T3), and DIO3 inactivates T3 and T4. The present work investigates the effects of overexpression of DIO3 to suppress TH signaling and thereby modulate cone death/survival. Subretinal delivery of AAV5-IRBP/GNAT2-hDIO3 induced robust expression of DIO3 in the mouse retina and significantly reduced the number of TUNEL-positive cells in the cone-dominant LCA model Rpe65 -/- /Nrl -/- mice. Our work shows that suppressing TH signaling by overexpression of DIO3 preserves cones, supporting that suppressing TH signaling locally in the retina may represent a treatment strategy for LCA management.

Hypothyroidism: a growing complication of cancer treatment.

Hypothyroidism is an often underreported complication of cancer treatment. With the growing number of biological and targeted therapies, hypothyroidism may become a more prevalent clinical problem. Signs and symptoms of hypothyroidism may be easily attributed to the cancer or cancer treatment, leading to unnecessary dose modifications or discontinuation of effective therapies. Furthermore, these symptoms have a negative effect on quality of life. Measurement of TSH levels in at-risk patients prior to initiating treatment and at regular intervals during treatment will allow early intervention and effective treatment of hypothyroidism.

Superiority of thyroid peroxidase DNA over protein immunization in replicating human thyroid autoimmunity in HLA-DRB1*0301 (DR3) transgenic mice.

Murine experimental autoimmune thyroiditis (EAT), characterized by thyroid destruction after immunization with thyroglobulin (Tg), has long been a useful model of organ-specific autoimmune disease. More recently, porcine thyroid peroxidase (pTPO) has also been shown to induce thyroiditis, but these results have not been confirmed. When (C57BL/6 x CBA)F(1) mice, recently shown to be susceptible to mouse TPO-induced EAT, were immunized with plasmid DNA to human TPO (hTPO) and cytokines IL-12 or GM-CSF, significant antibody (Ab) titres were generated, but minimal thyroiditis was detected in one mouse only from the TPO + GM-CSF immunized group. However, after TPO DNA immunization of HLA-DR3 transgenic class II-deficient NOD mice, thyroiditis was present in 23% of mice injected with TPO + IL-12 or GM-CSF. We also used another marker for assessing the closeness of the model to human thyroid autoimmunity by examining the epitope profile of the anti-TPO Abs to immunodominant determinants on TPO. Remarkably, the majority of the anti-TPO Abs was directed to immunodominant regions A and B, demonstrating the close replication of the model to human autoimmunity. TPO protein immunizations of HLA-DR3 transgenic mice with recombinant hTPO did not result in thyroiditis, nor did immunization of other mice expressing HLA class II transgenes HLA-DR4 or HLA-DQ8, with differential susceptibility to Tg-induced EAT. Moreover, our efforts to duplicate exactly the experimental procedures used with pTPO also failed to induce thyroiditis. The success of hTPO plasmid DNA immunization of DR3(+) mice, similar to our reports on Tg-induced thyroiditis and thyrotropin receptor DNA-induced Graves' hyperthyroidism, underscores the importance of DR3 genes for all three major thyroid antigens, and provides another humanized model to study autoimmune thyroid disease.