Triiodothyronine/Free Thyroxine Ratio as a Criterion for the Differentiation Between Graves' Disease and Subacute Thyroiditis.

BACKGROUND: Graves' disease (GD) and subacute thyroiditis (SAT) are important causes of thyrotoxicosis. The differentiation between these diseases is of great value because it will affect the management plan of either of them. The study aimed to assess the triiodothyronine/free thyroxine (T3/fT4) ratio as a criterion for the differentiation of hyperthyroidism due to GD and SAT. METHOD: A retrospective study with database retrieval was conducted at Faiha Specialized Diabetes, Endocrine and Metabolism Center (FDEMC), Basrah, southern Iraq. Patients attending the center who presented with thyrotoxicosis due to GD and SAT from January 2010 to January 2024 were included in the analysis that was conducted from October 2023 to February 2024. For comparison between GD and SAT, the baseline thyroid-stimulating hormone (TSH), fT4 and T3 were used to calculate the fT4 ratio (fT4 level (ng/dL)/1.7 ng/dL), T3 ratio (T3 level (ng/dL)/200 ng/dL), and T3/fT4 ratio (T3 level (ng/dL)/fT4 (ng/dL)). RESULTS: As compared to SAT, patients with GD had a significantly lower TSH and higher T3, T3 ratio, and T3/fT4 ratio. A T3/fT4 ratio with a cutoff equal to or more than 25 had 95% sensitivity and 18.1% specificity for GD with 94.4% positive predictive value. Raising the cutoff to equal or more than 100 results in the reduction of sensitivity to 32.7% but with 100% specificity and positive predictive value. CONCLUSION: The T3/fT4 ratio presents as a valuable diagnostic tool in differentiating GD from SAT, with potential applications in refining the diagnostic approach to hyperthyroidism.

Hypothyroidism after hemithyroidectomy: a systematic review and meta-analysis.

BACKGROUND: The incidence of hypothyroidism following hemithyroidectomy and risk factors associated with its occurrence are not completely understood. This systematic review investigated the incidence and risk factors for hypothyroidism, thyroxine supplementation following hemithyroidectomy as well as the course of post-operative hypothyroidism, including the time to hypothyroidism and incidence of transient hypothyroidism. METHODS: Searches were conducted in MEDLINE, EMBASE, Scopus, and Cochrane library for studies reporting the incidence of hypothyroidism or thyroxine supplementation following hemithyroidectomy. RESULTS: Sixty-six studies were eligible for inclusion: 36 reported risk factors, and 27 reported post-operative course of hypothyroidism. Median follow-up was 25.2 months. The pooled incidence of hypothyroidism was 29% (95% CI, 25-34%; P<0.001). Transient hypothyroidism occurred in 34% of patients (95% CI, 21-47%; P<0.001). The pooled incidence of thyroxine supplementation was 23% (95% CI, 19-27%; P<0.001), overt hypothyroidism 4% (95% CI, 2-6%, P<0.001). Risk factors for development of hypothyroidism included pre-operative thyroid stimulating hormone (TSH) (WMD, 0.87; 95% CI, 0.75-0.98; P<0.001), TSH ≥ 2 mIU/L (RR, 2.87; 95% CI, 2.43-3.40; P<0.001), female sex (RR, 1.19; 95% CI, 1.08-1.32; P=0.007), age (WMD, 2.29; 95% CI, 1.20-3.38; P<0.001), right sided hemithyroidectomy (RR, 1.35; 95% CI, 1.10-1.65, P=0.003), the presence of autoantibodies anti-TPO (RR, 1.92; 95% CI, 1.49-2.48; P<0.001), anti-Tg (RR, 1.53; 95% CI, 1.40-1.88; P<0.001), and Hashimoto's thyroiditis (RR, 2.05; 95% CI, 1.57-2.68; P=0.001). CONCLUSION: A significant number of patients will develop hypothyroidism or require thyroxine following hemithyroidectomy. An awareness of patient risk factors and postoperative thyroid function course will assist in counselling patients on their risk profile and guiding management.

Thyroxine regulates pig Sertoli cell line proliferation and maturation through the IKK/NFκB and p38 MAPK signaling pathways.

The aim of this study was to investigate the signaling pathways involved in the proliferation and differentiation of pig Sertoli cells (SCs) mediated by thyroid hormone (T3) to provide a theoretical and practical basis for enhancing pig semen production. The effects of different concentrations of T3 on the proliferation of pig SCs were evaluated using the CCK8 assay. The impact of T3 on the proliferation and differentiation of pig SCs was further examined using RNA-seq, qPCR, and Western Blotting techniques. Additionally, the involvement of the p38 MAPK and NFκB pathways in mediating the effects of T3 on SCs proliferation and differentiation was investigated. Our findings revealed a strong correlation between the dosage of T3 and the inhibition of pig SCs proliferation and promotion of maturation. T3 regulated the activation state of the NFκB signaling pathway by upregulating IKKα, downregulating IKKß, and promoting IκB phosphorylation. Furthermore, T3 facilitated SCs maturation by upregulating AR and FSHR expression while downregulating KRT-18. In conclusion, T3 inhibits pig SCs proliferation and promote pig SCs maturation through the IKK/NFκB and p38 MAPK pathways. These findings provide valuable insights into the mechanisms by which T3 influences the proliferation and maturation of pig SCs.

Thyroid hormone T4 mitigates traumatic brain injury in mice by dynamically remodeling cell type specific genes, pathways, and networks in hippocampus and frontal cortex.

The complex pathology of mild traumatic brain injury (mTBI) is a main contributor to the difficulties in achieving a successful therapeutic regimen. Thyroxine (T4) administration has been shown to prevent the cognitive impairments induced by mTBI in mice but the mechanism is poorly understood. To understand the underlying mechanism, we carried out a single cell transcriptomic study to investigate the spatiotemporal effects of T4 on individual cell types in the hippocampus and frontal cortex at three post-injury stages in a mouse model of mTBI. We found that T4 treatment altered the proportions and transcriptomes of numerous cell types across tissues and timepoints, particularly oligodendrocytes, astrocytes, and microglia, which are crucial for injury repair. T4 also reversed the expression of mTBI-affected genes such as Ttr, mt-Rnr2, Ggn12, Malat1, Gnaq, and Myo3a, as well as numerous pathways such as cell/energy/iron metabolism, immune response, nervous system, and cytoskeleton-related pathways. Cell-type specific network modeling revealed that T4 mitigated select mTBI-perturbed dynamic shifts in subnetworks related to cell cycle, stress response, and RNA processing in oligodendrocytes. Cross cell-type ligand-receptor networks revealed the roles of App, Hmgb1, Fn1, and Tnf in mTBI, with the latter two ligands having been previously identified as TBI network hubs. mTBI and/or T4 signature genes were enriched for human genome-wide association study (GWAS) candidate genes for cognitive, psychiatric and neurodegenerative disorders related to mTBI. Our systems-level single cell analysis elucidated the temporal and spatial dynamic reprogramming of cell-type specific genes, pathways, and networks, as well as cell-cell communications as the mechanisms through which T4 mitigates cognitive dysfunction induced by mTBI.

Interrelationship between thyroid hormones and reduced renal function, a review article.

BACKGROUND: Understanding the relationship of thyroid hormones with the development of chronic kidney disease (CKD) has important clinical implications for managing patients with both thyroid and kidney dysfunction. In this review, our purpose was to provide a thorough comprehension of the interplay between thyroid hormones, thyroid dysfunctions, and CKD. While there is evidence linking thyroid hormone levels to renal diseases, the association between thyroid hormones, specifically within the normal range, and the risk of CKD incidence is still a subject of debate. The Google Scholar, PubMed, Scopus, and Web of Science, were searched using the medical subject heading (MeSH) terms for the relevant keywords up to December 2023. CONCLUSION: Based on the review, the development of CKD is more consistently associated with higher serum TSH and thereafter lower serum free T3 levels; however, its association with free T4 is more controversial. Furthermore, subclinical and overt hypothyroidisms were considerably associated with incident CKD. Hyperthyroidism and Hashimoto thyroiditis might increase the risk of CKD.

Association Between Subclinical Thyroid Dysfunction and Cognitive Decline: Findings From the ELSA-Brasil Study.

BACKGROUND: Thyroid dysfunction has been associated with cognitive decline and dementia. However, the role of subtle thyroid hormone alterations in cognitive function is still debatable. METHODS: Participants without overt thyroid dysfunction aged 35-74 years at baseline were evaluated in 3 study waves (2008-2010, 2012-2014, and 2017-2019). We assessed baseline thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3). Cognitive performance was evaluated every 4 years in each wave using 10-word immediate and late recall, word recognition, semantic (animals category) and phonemic (letter f) verbal fluency, and the trail-making B-version tests. A global composite z-score was derived from these tests. The associations of TSH, FT4, and FT3 levels with cognitive decline over time were evaluated using linear mixed-effect models adjusted for sociodemographic, clinical, and lifestyle variables. RESULTS: In 9 524 participants (mean age 51.2 ±â€…8.9 years old, 51% women, 52% White), there was no association between baseline TSH, FT4, and FT3 levels and cognitive decline during the follow-up. However, increase in FT4 levels over time was associated with faster memory (ß = -0.004, 95% CI = -0.007; -0.001, p = .014), verbal fluency (ß = -0.003, 95% CI = -0.007; -0.0005, p = .021), executive function (ß = -0.004, 95% CI = -0.011; -0.003, p < .001), and global cognition decline (ß = -0.003, 95% CI = -0.006; -0.001, p = .001). Decrease in FT4 levels over time was associated with faster verbal fluency (ß = -0.003, 95% CI = -0.007; -0.0004, p = .025) and executive function (ß = -0.004, 95% CI = -0.007; -0.0003, p = .031) decline. CONCLUSIONS: An increase or decrease in FT4 levels over time was associated with faster cognitive decline in middle-aged and older adults without overt thyroid dysfunction during 8 years of follow-up.

Suppressed thyroid stimulating hormone levels after initiation of a subcutaneous glucagon-like peptide-1 receptor agonist in a post-thyroidectomy patient managed with levothyroxine case report.

OBJECTIVES: Glucagon-like peptide-1 receptor agonist (GLP-1 RA) therapy has demonstrated an increased risk of thyroid C-cell hyperplasia and C-cell tumors in rodents. Due to this risk, a boxed warning for this drug class exists for people with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2. There is a lack of data regarding any possible effect of GLP-1 RA therapy on serum thyroid levels. The objective of this case report is to describe a case of suppressed thyroid stimulating hormone levels after initiation of a subcutaneous semaglutide in a post-total thyroidectomy patient managed with levothyroxine in order to highlight the need for closer monitoring of these patients and further research in this area. CASE SUMMARY: The patient described in the case underwent a total thyroidectomy in 2015 with stable thyroid hormone replacement requirements with levothyroxine for 5 years until the initiation and titration of subcutaneous semaglutide. The reduction in thyroid stimulating hormone (TSH) after starting GLP-1 RA therapy necessitated a 25 percent dose reduction of levothyroxine from her original dose. PRACTICE IMPLICATIONS: This patient experienced suppressed TSH levels following initiation and titration of subcutaneous semaglutide. The etiology of these changes may be related to the direct effects of GLP-1 RA therapy on TSH levels, changes in absorption related to delayed gastric emptying rates, secondary to GLP-1 RA-associated weight loss, or a combination of these proposed mechanisms. It may be prudent to exercise more frequent monitoring of medications that require weight-based dosing and those with a narrow therapeutic index when initiating and titrating GLP-1 RA-based therapies and is an area of potential study.

Retrospective Cross-Sectional Study of the Relationship of Thyroid Volume and Function with Anthropometric Measurements, Body Composition Analysis Parameters, and the Diagnosis of Metabolic Syndrome in Euthyroid People Aged 18-65.

Background and Objectives: The thyroid is a key endocrine gland for the regulation of metabolic processes. A body composition analysis (BCA) is a valuable complement to the assessment of body mass index, which is derived only from body weight and height. This cross-sectional retrospective study aimed to investigate the relationships between thyroid volume (TV) and thyroid function parameters, anthropometric measurements, BCA parameters, and the presence of metabolic syndrome (MetS) in adults without clinically overt thyroid disease. Material and Methods: This study involved 45 people (females: 57.8%; MetS: 28.9%) hospitalized for planned diagnostics without signs of acute illness or a deterioration of their health and without thyroid disease, who underwent thyroid ultrasound scans, biochemical tests to assess their thyroid function, MetS assessments, anthropometric measurements, and BCAs using the bioelectrical impedance method. Results: The TV was significantly larger in people with MetS compared to people without MetS. The TV was significantly higher and the serum thyrotropin (TSH) concentration was significantly lower in overweight and obese people than in normal and underweight people. The free triiodothyronine (FT3) serum concentration and TV were correlated with waist circumference and some parameters of the BCA, and the FT3 concentration was also correlated with the body mass index, waist-hip ratio, and waist-height ratio. No significant correlations were found between the FT4 and TSH and the results of the anthropometric and BCA measurements. Conclusions: Even in a population of euthyroid patients without clinically overt thyroid disease, there were some significant relationships between the volume and function of the thyroid gland and the results of their anthropometric parameters, BCAs, and the presence of MetS features.

Serum Vitamin B12 and Holotranscobalamin Levels in Subclinical Hypothyroid Patients in Relation to Thyroid-Stimulating Hormone (TSH) Levels and the Positivity of Anti-thyroid Peroxidase Antibodies: A Case-Control Study.

Background Subclinical hypothyroidism (SCH) is characterized by elevated thyroid-stimulating hormone (TSH) levels, while thyroid hormones (free thyroxine (T4) and free triiodothyronine (T3)) remain within the reference ranges. Vitamin B12 (cobalamin) deficiency is common in patients with autoimmune disorders, including autoimmune hypothyroidism. The study was aimed at evaluating serum vitamin B12 levels and holotranscobalamin (HoloTC) levels in SCH patients and ascertaining their association with a risky level of TSH and the positivity of anti-thyroid peroxidase (anti-TPO) antibodies. Methodology A case-control study was conducted at Azadi Teaching Hospital, Duhok, a city in the Kurdistan region of Iraq, involving 153 participants, including 72 newly diagnosed SCH patients and 81 healthy controls. Serum levels of vitamin B12, HoloTC, TSH, free T4, free T3, and anti-TPO antibodies were measured based on different principles. Results The mean age of patients with SCH was 32.87±8.7 years, with predominantly females comprising 75% and 77.8% being less than 40 years of age. Moreover, the mean levels of serum TSH (6.96±2.68 µIU/L), anti-TPO antibodies (53.31±81.32 IU/ml), and HoloTC (41.93±19.42 pmol/l) were significantly higher in patients with SCH compared to healthy control participants (p < 0.05), whereas there was a non-significantly higher level of vitamin B12(320.72±98.42 pg/ml) among SCH patients compared to healthy control participants (p = 0.220). The mean levels of vitamin B12 (345.33±103.22 pg/ml) and HoloTC (40.14±18.16 pmol/l) were insignificantly lower in SCH patients with TSH levels more than 7 µIU/L (p > 0.05), as well as the mean levels of vitamin B12 (308.82±96.12 pg/ml) and HoloTC (41.14±19.29 pmol/l) insignificantly lower in SCH patients with positive anti-TPO antibodies (p > 0.05).  Conclusions This study highlights the potential association between SCH and altered vitamin B12 status, particularly evident in HoloTC levels. The presence of positive anti-TPO antibodies and the degree of elevation in TSH levels may exacerbate vitamin B12 deficiency in SCH patients.

Solving the Dilemma: Van Wyk-Grumbach Syndrome.

The Van Wyk-Grumbach syndrome (VWGS) (hypothyroidism, ovarian mass, and precocious puberty) has been extensively documented in the literature as long-term hypothyroidism manifesting as an ovarian mass. The authors of this study describe this entity in a young girl, aged 10, who presented with abdominal pain with a multiloculated ovarian cyst. She was evaluated, and it was discovered that she had delayed bone age, precocious puberty, and a small height. Following her diagnosis of autoimmune thyroiditis and the initiation of thyroxine replacement therapy, the ovarian cysts spontaneously regressed. To avoid needless assessment and surgical mishaps, this entity should be considered in situations of ovarian mass, particularly those with precocious puberty and thyroid disorders.

Defining gestational thyroid dysfunction through modified non-pregnancy reference intervals: an individual participant meta-analysis.

BACKGROUND: Establishing local trimester-specific reference intervals for gestational TSH and FT4 is often not feasible, necessitating alternative strategies. We aimed to systematically quantify the diagnostic performance of standardized modifications of center-specific non-pregnancy reference intervals as compared to trimester-specific reference intervals. METHODS: We included prospective cohorts participating in the Consortium on Thyroid and Pregnancy. After relevant exclusions, reference intervals were calculated per cohort in thyroperoxidase antibody-negative women. Modifications to the non-pregnancy reference intervals included an absolute modification (per 0.1 mU/L TSH or 1 pmol/L FT4), relative modification (in steps of 5%) and fixed limits (upper TSH limit between 3.0 to 4.5 mU/L and lower FT4 limit 5-15 pmol/L). We compared (sub)clinical hypothyroidism prevalence, sensitivity and positive predictive value (PPV) of aforementioned methodologies with population-based trimester-specific reference intervals. RESULTS: The final study population comprised 52,496 participants in 18 cohorts. Optimal modifications of standard reference intervals to diagnose gestational overt hypothyroidism were -5% for the upper limit of TSH and +5% for the lower limit of FT4 (sensitivity 0.70, confidence interval [CI] 0.47-0.86; PPV 0.64, CI 0.54-0.74). For subclinical hypothyroidism, these were -20% for the upper limit of TSH and -15% for the lower limit of FT4 (sensitivity 0.91, CI 0.67-0.98; PPV 0.71, CI 0.58-0.80). Absolute and fixed modifications yielded similar results. Confidence intervals were wide, limiting generalizability. CONCLUSION: We could not identify modifications of non-pregnancy TSH and FT4 reference intervals that would enable centers to adequately approximate trimester-specific reference intervals. Future efforts should be turned towards studying the meaningfulness of trimester-specific reference intervals and risk-based decision limits.

The Relationship between Thyroid Hormones and Insulin Resistance in Polycystic Ovary Syndrome Women.

OBJECTIVE: This study aimed to investigate the changes in thyroid hormones in the serum of patients with polycystic ovary syndrome (PCOS) and their correlation with insulin resistance. DESIGN: This is a retrospective study. PARTICIPANTS: 84 patients having insulin resistance and 76 patients without insulin resistance were included. 90 women without history of PCOS were selected as a healthy control group. SETTINGS: This study was conducted at Shijiazhuang Fourth Hospital. METHODS: Blood samples were collected from each group on days 3-5 of their menstrual cycle, and their triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) levels were analyzed and compared between groups. RESULTS: We investigated the changes of serum thyroid hormones in patients with PCOS and their correlation with insulin resistance. We found that serum levels of T3 and T4 were significantly decreased, while TSH levels were significantly increased in PCOS patients compared with HCs. Moreover, we found that patients with insulin resistance had significantly lower levels of serum T3 and T4 and higher levels of TSH compared to those PCOS participants without insulin resistance. LIMITATIONS: This study was a retrospective and single-center study, which had selection bias, information bias, and confounding variables may affect the accuracy and reliability of the conclusion. CONCLUSIONS: Insulin resistance negative correlates with their serum T3, T4, and positive correlates with their TSH levels. Our results develop a combined test model with the serum T3, T4, and TSH levels for the clinical diagnosis of insulin resistance in PCOS women.

A Case of Myxedema Edema in a Patient With Factors XI and XII Deficiency and Sepsis: Unveiling Complications and Management Strategies.

Hypothermic patients are rarely encountered in the emergency department (ED), indicating a potentially critical condition requiring immediate attention and diagnosis. Myxedema coma, a severe complication of hypothyroidism, presents as profound hypothermia and demands early recognition and proper treatment. We report the case of a 77-year-old female with no prior medical history of hypothyroidism. She presented to the ED with a one-and-a-half-month history of weakness, hypothermia, decreased mental status, and edema. Laboratory analysis confirmed hypothyroidism, leading to a diagnosis of myxedema coma. Treatment with thyroxine and glucocorticoid supplements resulted in a favorable outcome without complications. In conclusion, myxedema coma should be considered in hypothermic patients with altered mental status, even without a history of hypothyroidism. Prolonged hypothyroidism or acute events like sepsis, cerebrovascular accidents, gastrointestinal bleeding, cold exposure, trauma, or certain medications can precipitate this condition, emphasizing the need for prompt treatment initiation.

A Case Report of an Acute Severe Tachyarrhythmia Presentation With Underlying Cardiomyopathy in a Patient With Anabolic Androgenic Steroid and Thyroxine Misuse.

A description of an acute hospital presentation with severe tachyarrhythmia requiring multiple direct current cardioversions in a 45-year-old male bodybuilder with underlying cardiomyopathy possibly caused by long-term anabolic steroid abuse and more recent thyroxine misuse is described. A review of the literature regarding the above associations was also done. This case report further adds to the literature regarding the harmful effect of androgenic anabolic steroid misuse (with the added effect of thyroxine misuse in this case) on the heart.

Increased Absorption of Thyroxine in a Murine Model of Hypothyroidism Using Water/CO2 Nanobubbles.

Thyroxine (T4) is a drug extensively utilized for the treatment of hypothyroidism. However, the oral absorption of T4 presents certain limitations. This research investigates the efficacy of CO2 nanobubbles in water as a potential oral carrier for T4 administration to C57BL/6 hypothyroid mice. Following 18 h of fasting, the formulation was administered to the mice, demonstrating that the combination of CO2 nanobubbles and T4 enhanced the drug's absorption in blood serum by approximately 40%. To comprehend this observation at a molecular level, we explored the interaction mechanism through which T4 engages with the CO2 nanobubbles, employing molecular simulations, semi-empirical quantum mechanics, and PMF calculations. Our simulations revealed a high affinity of T4 for the water-gas interface, driven by additive interactions between the hydrophobic region of T4 and the gas phase and electrostatic interactions of the polar groups of T4 with water at the water-gas interface. Concurrently, we observed that at the water-gas interface, the cluster of T4 formed in the water region disassembles, contributing to the drug's bioavailability. Furthermore, we examined how the gas within the nanobubbles aids in facilitating the drug's translocation through cell membranes. This research contributes to a deeper understanding of the role of CO2 nanobubbles in drug absorption and subsequent release into the bloodstream. The findings suggest that utilizing CO2 nanobubbles could enhance T4 bioavailability and cell permeability, leading to more efficient transport into cells. Additional research opens the possibility of employing lower concentrations of this class of drugs, thereby potentially reducing the associated side effects due to poor absorption.

Curcumin-loaded nanoparticles effectively prevent T4-induced oxidative stress in rat heart.

In this study, we report the cardioprotective effect of the glycerol monooleate (GMO) based nanocurcumin in both in vitro and in vivo conditions under a hyperthyroid state. The heart is one of the primary target organs sensitive to the action of thyroid hormone, and slight variations in the thyroid hormone serum concentrations result in measurable changes in cardiac performance. Hyperthyroidism-induced hypermetabolism is associated with oxidative stress and is an important mechanism responsible for the progression of heart failure. Curcumin has been known to play a protective role against oxidative stress-related diseases like Alzheimer's, asthma, and aging due to its antioxidant properties. Nevertheless, its potent biological activity has been hindered due to its poor bioavailability. To overcome this drawback, a GMO-based biodegradable nanoparticle (NP) formulation loaded with curcumin has been developed, and the protective effect of curcumin-loaded NPs was compared against the native drug. Oxidative stress parameters like reactive oxygen species (ROS) release, change in mitochondrial membrane permeability, lipid peroxidation (LPx), lactate dehydrogenase (LDH) release, and the activity and protein expression of the endogenous antioxidant enzymes like superoxide dismutase, catalase (CAT) and glutathione peroxidase were evaluated. The results from in vitro showed that curcumin-loaded NPs showed better DPPH and NO radical scavenging activity than native curcumin in a concentrations range of 2.5-20 µM. It was also observed that the nanoparticulate curcumin was comparatively more effective than native curcumin in protecting against ROS-induced membrane damage by reducing LPx and LDH leakage at low concentrations of 5-10 µM. Further, curcumin NPs performed better in facilitating the activities of antioxidant enzymes under in vitro and in vivo conditions with respect to time and concentrations, resulting in reduced cellular ROS levels. In this scenario, we anticipate that curcumin-loaded NPs can serve as a better antioxidant than its native counterpart in protecting the heart from oxidative stress-related diseases.

Relationship of thyroid function with genetic subtypes and treatment with growth hormone in Prader-Willi syndrome.

Prader-Willi syndrome (PWS) is the most common genetic syndrome with obesity and results from loss of expression of paternally inherited genes on chromosome 15q11-q13 by a variety of mechanisms which include large deletions (70%-75%), maternal uniparental disomy (UPD) (20%-30%), and imprinting defects (2%-5%) or balanced translocations. Individuals often have a characteristic behavior disorder with mild intellectual disability, infantile hypotonia associated with poor sucking, short stature, and obesity. PWS is characterized by hypothalamic-pituitary axis dysfunction with growth hormone (GH) deficiency, hypogonadism, and several other hormonal deficiencies resulting in short stature, centrally driven excessive appetite (hyperphagia), central obesity, cryptorchidism, and decreased lean body mass. In this study, we determined and sought differences in the incidence of thyroid abnormalities among the common genetic subtypes in a cohort of 52 subjects with PWS because there was limited literature available. We also sought the effects of growth hormone (GH) treatment on the thyroid profile. Fifty-two subjects with a genetically confirmed diagnosis of PWS were included in this study at the University of California, Irvine. Blood samples for baseline thyroxine stimulating hormone (TSH) and free thyroxine (fT4) levels were obtained in the morning after an overnight fast for 8-12 h. Statistical analyses were performed with SPSS (SPSS Inc., 21.0). Mean values were analyzed by one-way ANOVA, and student's t-test and statistical significance were set at p < 0.05. The subjects included 26 males and 26 females with an age range of 3-38 years. There were 29 subjects with chromosome 15q11-q13 deletions and 23 with UPD; 28 were GH treated currently or in the past, and 24 never received GH. There was no significant difference in age or body mass index (BMI) (kg/m2) between GH-treated versus non-GH-treated groups. BMI was higher in the deletion group compared to the UPD group (p = 0.05). We identified two individuals who were clinically diagnosed and treated for hypothyroidism, one of whom was on GH supplements. We identified two additional individuals with subclinical hypothyroidism who were not on GH treatment, giving a frequency of 7.6% (4/52) in this cohort of patients. We did not find significant differences in thyroid function (TSH) in the deletion versus UPD groups. We found significant differences in thyroid function, however, between GH-treated and non-GH-treated groups. The mean TSH was lower (2.25 ± 1.17 uIU/M, range 0.03-4.92 uIU/M versus 2.80 ± 1.44 uIU/M, range 0.55-5.33 uIU/M respectively, p = 0.046), and the free T4 levels were significantly higher (1.13 ± 0.70 and 1.03 ± 0.11 ng/dL, respectively, p = 0.05) in the GH-treated individuals compared to non-GH-treated individuals. In this cohort of subjects with PWS, we identified two previously diagnosed individuals with hypothyroidism and two individuals with subclinical hypothyroidism (4/52, 7.6%), three of whom were not receiving GH treatment. We did not find any significant differences in thyroid function between molecular subtypes; however, we found that euthyroid status (lower TSH levels and higher free T4 levels) was significantly higher in individuals who were treated with GH compared to the untreated group. We recommend that individuals with PWS should be screened regularly for thyroid deficiency and start treatment early with GH in view of the potentially lower incidence of thyroid deficiency.

Associations between a normal-range free thyroxine concentration and ovarian reserve in infertile women undergoing treatment via assisted reproductive technology.

BACKGROUND: Some recent studies have shown that female subclinical hypothyroidism (SCH) is associated with diminished ovarian reserve (DOR). In this study, we aimed to investigate whether serum-free thyroxine (fT4) concentrations within the reference range are associated with ovarian reserve in women. METHODS: This cross-sectional study included 4933 infertile women with normal-range fT4 concentrations who received assisted reproductive technology treatment in our clinic. The data of women in different fT4 concentration tertiles (namely 12-15.33, 15.34-18.67, and 18.68-22 pmol/L) were compared with ovarian reserve markers, namely the anti-Müllerian hormone (AMH) concentration, the antral follicle count (AFC), and the number of aspirated oocytes. The primary outcomes were the AMH concentration and the risk of DOR, diagnosed as an AMH concentration < 1.1 ng/mL. RESULTS: The average ages of women in the low-normal, middle-normal, and high-normal fT4 tertiles were 33.20 (standard deviation [SD]: 5.11), 32.33 (SD: 5.13), and 31.61 (SD: 5.10) years, respectively (p < 0.0001). AMH concentrations (adjusted mean: 3.32 [95% confidence interval {CI}: 3.16 to 3.50] vs. 3.51 [3.40 to 3.62] vs. 3.64 [3.50 to 3.80] ng/mL, p = 0.022) were significantly different between the fT4 concentration tertiles. The risk of DOR was significantly increased in the low-normal (adjusted odds ratio: 1.61 [95% CI: 1.01 to 2.58]) and middle-normal (1.47 [95% CI: 1.00 to 2.16]) tertiles compared with the high-normal tertile. Subgroup analysis showed that AMH concentrations were significantly different among the fT4 concentration tertiles in women aged < 35 years (adjusted mean: 3.94 [95% CI: 3.70 to 4.20] vs. 4.25 [4.11 to 4.39] vs. 4.38 [4.18 to 4.58], p = 0.028), whereas this difference was not significant in women aged ≥ 35 years (p = 0.534). The general additive models using fT4 as a continuous variable indicated that a lower fT4 concentration within the normal range was significantly associated with a lower AMH concentration (p = 0.027), a lower AFC (p = 0.018), a lower number of aspirated oocytes (p = 0.001), and a higher risk of DOR (p = 0.007). CONCLUSION: Low-normal fT4 concentrations are associated with lower ovarian reserve in infertile women.

The predictive value of free thyroxine combined with tubular atrophy/interstitial fibrosis for poor prognosis in patients with IgA nephropathy.

Background: IgA nephropathy (IgAN), the most common type of glomerulonephritis, has great individual differences in prognosis. Many studies showed the relationship between thyroid hormones and chronic kidney disease. However, the relationship between free thyroxine (FT4), as a thyroid hormone, and IgAN is still unclear. This study aimed to evaluate the impact of FT4 on IgAN prognosis. Methods: This retrospective study involved 223 patients with biopsy-proven IgAN. The renal composite outcomes were defined as: (1) ESRD, defined as eGFR < 15 ml/(min·1.73 m2) or initiation of renal replacement therapy (hemodialysis, peritoneal dialysis, renal transplantation); (2) serum creatinine doubled from baseline; (3) eGFR decreased by more than 50% from baseline. The predictive value was determined by the area under the curve (AUC). Kaplan-Meier and Cox proportional hazards analyses assessed renal progression and prognosis. Results: After 38 (26-54) months of follow-up, 23 patients (10.3%) experienced renal composite outcomes. Kaplan-Meier survival curve analysis showed that the renal survival rate of the IgAN patients with FT4<15.18pmol/L was lower than that with FT4≥15.18pmol/L (P < 0. 001). Multivariate Cox regression model analysis showed that FT4 was a protective factor for poor prognosis of IgAN patients, whether as a continuous variable or a categorical variable (HR 0.68, 95%CI 0.51-0.90, P =0.007; HR 0.04, 95%CI 0.01-0.20, P <0.001). ROC curve analysis showed that FT4 combined with t score had a high predictive value for poor prognosis of IgAN patients (AUC=0.881, P<0.001). Conclusion: FT4 was a protective factor for IgAN. In addition, FT4 combined with tubular atrophy/interstitial fibrosis had a high predictive value for poor prognosis of IgAN.

Thyroid disorders and gastrointestinal dysmotility: an old association.

Gastrointestinal motility symptoms may be closely related to thyroid diseases. Sometimes, such symptoms are the only thyroid disease-related clue although the degree of the symptoms may vary. The exact mechanism of action of thyroid hormones on gastrointestinal motility is not completely understood, however, a clue lies in the fact that muscle cell receptors can be directly acted upon by thyroxines. Both hypo- and hyperthyroidism can cause impairment of gastrointestinal motility, modifying structure and function of pharynx and esophagus, and regulating esophageal peristalsis through neuro-humoral interaction. In hyperthyroid patients, alterations of postprandial and basic electric rhythms have been observed at gastro-duodenal level, often resulting in slower gastric emptying. Gastric emptying may also be delayed in hypothyroidism, but an unrelated gastric mucosa-affecting chronic modification may also cause such pattern. Hyperthyroidism commonly show malabsorption and diarrhoea, while hypothyroidism frequently show constipation. In summary, it can be stated that symptoms of gastrointestinal motility dysfunction can be related to thyroid diseases, affecting any of the gastrointestinal segment. Clinically, the typical thyroid disease manifestations may be missing, borderline, or concealed because of intercurrent sicknesses. Motility-linked gastrointestinal problems may easily conceal a misdetected, underlying dysthyroidism that should be carefully analyzed. Here, we aim to elaborate on the associations between thyroid disorders and GI dysmotility and the common clinical manifestations associated with GI dysmotility.