Update on subclinical thyroid dysfunction

ChIP-seq and RNA-seq Reveal the Involvement of Histone Lactylation Modification in Early Pregnancy with Subclinical Hypothyroidism

Subclinical hypothyroidism (SCH) is associated with multiple adverse outcomes in early pregnancy. This study aims to explore the regulatory mechanisms underlying histone lactylation modification in early pregnancy with SCH. Peripheral blood mononuclear cells were collected from early pregnant women with or without SCH. RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) analyses were performed to identify the transcriptional pattern and histone lactylation modification in early pregnancy with SCH. RNA-seq analysis revealed that the differentially expressed genes associated with the extracellular matrix exhibited a significant downregulation in early pregnancy with SCH (EP_SCH) compared to early pregnancy without SCH (EP), while those involved in apoptosis were significantly upregulated. In the ChIP-seq analysis, 1660 hypomodified and 766 hypermodified H3K18la-binding peaks were identified in the EP_SCH group compared to the EP group. The hypomodified genes in early pregnancy with SCH compared to its control were enriched in GO terms of apoptotic process and differentiation of immune cells. The genes with increased H3K18 lactylation in early pregnancy with SCH compared to its control were associated with the nervous system, female pregnancy, and the OXT signaling pathway. When RNA-seq data was integrated with ChIP-seq data, we found that the expression and H3K18la enrichment of KCTD7, SIPA1L2, HDAC9, BCL2L14, TXNRD1, and SGK1 were increased in early pregnancy with SCH compared to its control, which was further confirmed by RT-qPCR and ChIP-PCR analyses. This study identifies the changes in histone lactylation modification in early pregnancy with SCH. These findings provide novel insights into the regulatory mechanisms of SCH during early pregnancy.

Stimulated Thyrotropin (TSH) Levels Were Inversely Correlated with Age

Purpose

Serum Thyrotropin (TSH) levels in the elderly have been reported to be inconsistent in different studies. One of the difficulties in determining the effect of aging on TSH levels is that TSH levels are influenced by various factors, including thyroid-related factors. Therefore, this study aimed to assess the effect of aging on TSH levels while controlling for thyroid factors.

Patients and Methods

This study included a total of 343 subjects, who underwent thyroidectomy, levothyroxine (LT4) supplementation and withdraw. All participants were divided into young(18-44year old), middle(45-59year old), and old age(>60year old) groups based on their age. The clinical data of the subjects were reviewed, and analyzed based on their age.

Results

With LT4 supplementation, there was no difference in free triiodothyronine (FT3), free thyroxine (FT4), and TSH levels among the three age groups. However, after approximately 4 weeks of LT4 withdrawal, the TSH levels of the three groups showed significant differences. The median stimulated TSH levels were 100, 83.1, and 64.6 mIU/L in the young, middle, and old age groups, respectively (P<0.01). Moreover, the percentages of subjects, with TSH levels higher than 100 mIU/L, were 63.2%, 33.1%, and 12.9% (P<0.01) in the young, middle, and old age groups, respectively. Spearman correlation analysis (R=-0.42, P<0.01) and partial correlation analysis (R=-0.44, P<0.01) revealed an inverse correlation between age and TSH levels after LT4 withdrawal.

Conclusion

Aging plays an important role in TSH regulation. Age was inversely related to the stimulated TSH levels. The effect of senescence on TSH levels, as well as the underlying regulatory mechanisms, warrant further investigation.

The impact of thyroid disorder on cardiovascular disease: Unraveling the connection and implications for patient care

The thyroid gland is responsible for metabolism, as well as cardiac function and the peripheral vascular system. Thyroid dysfunctions are associated with an increase in the risk of cardiovascular diseases, including heart failure and coronary heart disease atrial fibrillation, by impairing heart contractility, stroke volume, heart rate, peripheral vascular resistance, and electrical activity. Thyroid dysfunctions also alter several cardiovascular risk factors, such as atherosclerosis, hypertension, and dyslipidemia, as well as causing stroke, which is associated with atrial fibrillation. An antiarrhythmic drug, amiodarone, may also induce both thyrotoxicosis and hypothyroidism, so its use requires serial thyroid function testing. Every CVD patient is recommended to be screened and treated for any possible thyroid dysfunction to reduce the patient's mortality and morbidity.

Possible association between subclinical hypothyroidism and age at menopause in Colombian women

OBJECTIVE

To evaluate the association between subclinical hypothyroidism with early menopause, premature menopause, and last menstrual bleeding before the natural age of menopause.

METHODS

This was a cross-sectional study conducted in 643 postmenopausal women aged 40-69 years. Groups were formed according to last menstrual episode: ≥45 [Natural age at menopause], 40-44 and [Early menopause], <40 [Premature menopause], and <45 [last menstrual episode before the natural age of menopause]. The Zulewski scale was applied to identify manifestations related to hypothyroidism and subclinical hypothyroidism, diagnosed with a serum TSH > 4.5 µIU/mL plus T4-free between 0.7 and 1.9 ng/dL.

RESULTS

It was found that 24.4% had the last menstrual episode before the natural age of menopause, 18.6% had early menopause, and 5.7% had premature menopause. Subclinical hypothyroidism was diagnosed in 4.5% of patients. Among women with subclinical hypothyroidism, there was a higher frequency of early menopause, premature menopause, and last menstrual episode before the natural age of menopause, than in women without subclinical hypothyroidism (p < 0.05). Paresthesia (50%) and dry skin (40.7%) were the most reported hypothyroidism-related manifestations. Early menopause, premature menopause, and last menstrual episode before the natural age of menopause were associated with subclinical hypothyroidism, OR: 3.37 [95% CI: 1.40-8.10], OR: 4.31 [95% CI: 1.24-14.97], and OR: 3.57 [95% CI: 1.57-8.10], respectively.

CONCLUSIONS

The last menstrual episode before the natural age of menopause, early menopause, and premature menopause were significantly associated with a higher chance of subclinical hypothyroidism.

Establishment of a Quenchbody-based L-thyroxine detection method and its comparison with ELISA systems

The quantification of L-thyroxine (T4) is crucial for regulating metabolism, diagnosing diseases, and monitoring the efficacy of T4 replacement therapy. However, because T4 is a hapten biomarker with a molecular weight of 777 g/mol, conventional immunoassay approaches, including Western blotting and some types of ELISA, have limited accuracy in the quantification of small molecules, including T4. Furthermore, these methods are time-consuming and involve multiple incubation and reaction steps. Therefore, a novel immunoassay method is required for simple and rapid on-site detection of T4. In this study, we expressed a recombinant anti-T4 single-chain variable fragment (scFv) in soluble form using Escherichia coli. The scFv exhibited high T4-binding efficiency, and T4 concentration-dependent titration curves indicated that the sandwich ELISA could detect T4 in the nanogram range. We labeled the scFv using a fluorescent dye for a Quenchbody (Q-body)-based one-pot immunoassay, which yielded a T4 concentration-dependent fluorescent response in 3 min. A comparison of the Q-body-based T4 detection system with ELISA-based methods demonstrated that the ELISA system was more sensitive but the Q-body assay was more rapid. Therefore, both ELISA and Q-body systems can be used depending on the experimental purpose, with the newly developed anti-T4 Q-body system being applicable for convenient in situ immunoassay of T4.

Assessing the causal relationship between obesity and hypothyroidism using Mendelian randomization

To explore the causal relationship between obesity and hypothyroidism and identify risk factors and the predictive value of subclinical hypothyroidism (SCH) in obese patients using Mendelian randomization, this study employed five Mendelian randomization methods (MR Egger, Weighted Median, Inverse Variance Weighted, Simple Mode, and Weighted Mode) to analyze clinical data from 308 obese patients at the People's Hospital of Xinjiang Uygur Autonomous Region, from January 2015 to June 2023. Patients were divided based on thyroid function tests into normal (n = 173) and SCH groups (n = 56). Comparative analyses, along with univariate and multivariate logistic regression, were conducted to identify risk factors for SCH in obese patients. A significant association between obesity and hypothyroidism was established, especially highlighted by the inverse variance weighted method. SCH patients showed higher ages, thyroid-stimulating hormone levels, and thyroid autoantibody positivity rates, with lower T4 and FT4 levels. Age, FT4, thyroid autoantibodies, TPO-Ab, and Tg-Ab were confirmed as risk factors. The predictive value of FT4 levels for SCH in obesity was significant, with an Area Under the Curve (AUC) of 0.632. The study supports a potential causal link between obesity and hypothyroidism, identifying specific risk factors for SCH in obese patients. FT4 level stands out as an independent predictive factor, suggesting its utility in early diagnosis and preventive strategies for SCH.

An Evaluation of the Efficacy of Machine Learning in Predicting Thyrotoxicosis and Hypothyroidism: A Comparative Assessment of Biochemical Test Parameters Used in Different Health Checkups

Objective This study assessed the efficacy of machine learning in predicting thyrotoxicosis and hypothyroidism [thyroid-stimulating hormone >10.0 mIU/L] by leveraging age and sex as variables and integrating biochemical test parameters used by the Japan Society of Health Evaluation and Promotion (JHEP) and the Japan Society of Ningen Dock (JND). Methods Our study included 20,653 untreated patients with Graves' disease, 3,435 untreated patients with painless thyroiditis, 4,266 healthy individuals, and 18,937 untreated patients with Hashimoto's thyroiditis. Machine learning was conducted using Prediction One on three distinct datasets: the Ito dataset (age, sex, and 30 blood tests and biochemical test data), the JHEP dataset (age, sex, and total protein,total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (γGTP), alkaline phosphatase, creatinine (CRE), uric acid (UA), and T-Cho test data), and the JND dataset (age, sex, and AST, ALT, γGTP, CRE, and UA test data). Results The results for distinguishing thyrotoxicosis patients from the healthy control group showed that the JHEP dataset yielded substantial discriminative capacity with an area under the curve (AUC) of 0.966, sensitivity of 92.2%, specificity of 89.1%, and accuracy of 91.7%. The JND dataset displayed similar robustness, with an AUC of 0.948, sensitivity of 92.0%, specificity of 81.3%, and accuracy of 90.4%. Differentiating hypothyroid patients from the healthy control group yielded similarly robust performances, with the JHEP dataset yielding AUC, sensitivity, specificity, and accuracy values of 0.864, 84.2%, 72.1%, and 77.4%, respectively, and the JND dataset yielding values of 0.840, 83.2%, 67.2%, and 74.3%, respectively. Conclusion Machine learning is a potent screening tool for thyrotoxicosis and hypothyroidism.

Impact of metformin on hypothalamic-pituitary-thyroid axis activity in women with autoimmune and non-autoimmune subclinical hypothyroidism: a pilot study

BACKGROUND

Metformin reduces plasma TSH levels if these levels are elevated. No study has investigated whether the hormonal effects of metformin are impacted by thyroid autoimmunity. The current study aimed to compare the effect of metformin on hypothalamic-pituitary-thyroid axis activity between subjects with mild hypothyroidism of different origins.

METHODS

The study population consisted of two groups of women with prediabetes and mildly elevated TSH levels, matched by age, insulin sensitivity, TSH, and thyroid hormone levels. Group A included 26 women with autoimmune thyroiditis, while group B enrolled 26 individuals with hypothyroidism of non-autoimmune origin. Both groups were treated with metformin (2.55-3 g daily). Circulating levels of TSH, total and free thyroid hormones, glucose, insulin, prolactin, high-sensitivity C-reactive protein (hsCRP) and 25-hydroxyvitamin D, concentrations of thyroid antibodies, and structure parameters of thyroid homeostasis were assessed at baseline and 6 months later.

RESULTS

All patients completed the study. At baseline, both groups differed in concentrations of thyroid peroxidase antibodies, thyroglobulin antibodies, hsCRP, and 25-hydroxyvitamin D. The drug reduced TSH and Jostel's index, with no difference between the study groups. The improvement in insulin sensitivity, observed in both groups, was more pronounced in group B than in group A. In women with autoimmune hypothyroidism, the drug increased SPINA-GT and decreased hsCRP levels. The remaining markers did not change throughout the study.

CONCLUSIONS

The obtained results suggest that, despite differences in thyroid output, the impact of metformin on TSH levels is similar in hypothyroid women with and without thyroid autoimmunity.

Analysis of Subclinical Thyroid Dysfunction and Metabolic Abnormality in 28568 Healthy People

We analyzed the detection rates of metabolic syndrome (MetS) and subclinical thyroid dysfunction, including subclinical hyperthyroidism (SCHyper) and subclinical hypothyroidism (SCH), in healthy people, as well as their relationship. Clinical data were collected from 28,568 healthy individuals who underwent physical examinations. The detection rates of SCHyper, SCH, and MetS, as well as in different genders and ages, were analyzed. The detection rate of SCHyper and SCH in females was significantly higher than that in males (P < 0.001), but that of MetS in males was significantly higher than that in females (P < 0.001). In each age group, the detection rate of SCH in females was higher than that in males (P < 0.001). The detection rate of SCH was significantly different in different age groups (P < 0.001). The detection rates of hyperlipidemia (P < 0.001), obesity (P = 0.004), hypertension (P = 0.009), and hyperglycemia (P < 0.001) in the female SCH group were significantly higher than those in the normal group. The detection rates of hyperlipidemia (P = 0.006), obesity (P = 0.04), and hypertension (P = 0.04) in the male SCH group were higher than those in the normal group. The males with SCHyper were more prone to hyperlipidemia (P = 0.02) and obesity (P = 0.03). In addition, the female SCHyper group was not significantly different from the normal group (P > 0.05). Conclusively, the detection rate of SCHyper and SCH in females is higher than that in males, which increases with age. Attention should be paid to subclinical thyroid dysfunction in elderly people, especially females. Early individualized screening and early intervention should be carried out for people with abnormal metabolism.

Normative range of various serum hormonal parameters among Indian women of reproductive age: ICMR-PCOS task force study outcome

Background

The hormonal profile varies considerably with age, gender, ethnicity, diet or physiological state of an individual. Limited population-specific studies have studied the variations in hormonal parameters among apparently healthy women. We aimed to analyse the biological reference interval for various hormonal parameters in the reproductive-aged healthy Indian women.

Methods

Out of 3877 participants that were clinically evaluated, 1441 subjects were subjected to laboratory investigations. All participants underwent a detailed clinical, biochemical and hormonal profiling. The hormone analysis was carried out at a single centre using a uniform methodology. Among the participants evaluated for biochemical and hormonal parameters, subjects that presented any abnormal profile or had incomplete investigations (n = 593) were excluded for further analysis.

Findings

The mean age (±SD) of the subjects retained in the final analysis (n = 848) was 29.9 (±6.3) years. In the present study, the biological reference interval (2.5th-97.5th centile) observed were: serum T4: μg/dL (5.23-12.31), TSH: μg/mL (0.52-4.16) and serum prolactin: ng/mL (5.13-37.35), LH: mIU/mL (2.75-20.68), FSH: mIU/mL 2.59-15.12), serum total testosterone: ng/mL (0.06-0.68), fasting insulin: mIU/mL (1.92-39.72), morning cortisol: μg/dL (4.71-19.64), DHEAS:μg/dL (50.61-342.6) and SHBG: nmol/L (21.37-117.54). Unlike T4, TSH, LH, and E2, the biological reference interval for prolactin, FSH, testosterone, C-peptide insulin and DHEAS varied when the subjects were stratified by age (p < 0.05). The comparative analysis showed marginal differences in the normative ranges for the hormones analysed among different populations.

Interpretation

Our first large composite data on hormonal measures will benefit future endeavours to define biological reference intervals in reproductive-aged Indian women.

Funding

The study was financially supported by the grant-in-aid from ICMR vide file No:5/7/13337/2015-RBMH.

The relationship between thyroid hormones and lipid profile in subclinical hypothyroidism female patients

Background and objectives: Subclinical thyroid disorder is a most common subclinical disease among many medical conditions such as cardiovascular disease and subclinical Lyme disease. The aim of this study was to determine the relationship between lipid profile results, lipid ratios, and anthropometric parameters and thyroid hormones. Methods: One hundred patients (ages 20 to 50 years) with subclinical hypothyroidism (SHT group) and 50 healthy subjects (control group), who are age-matched with patients, were included in the current study. Thyroid function tests (TSH, T3 and T4) were determined by immunodiagnostic assay system (VIDAS) for all participants. The serum glucose and lipid profile tests parameters were evaluated by Biolis 24i Premium chemistry analyser. In addition, systolic and diastolic blood pressure were measured for each individual in the study using mercury sphygmomanometer. Results: The levels of high-density lipoprotein-cholesterol (HDL-c) were significantly lower in the SHT group when compared with control group. Whereas, the level of low-density lipoprotein-cholesterol (LDL-c), the ratios total cholesterol (TC)/HDL-c and LDL-c/HDL-c were significantly higher in SHT group than in controls. Moreover, TSH was negatively correlated with diastolic blood pressure. Conclusions: Both LDL-c and HDL-c are altered in subclinical hypothyroidism patients. And, there is a negative association between TSH and diastolic blood pressure.

The Relationship between Gastrointestinal Health, Micronutrient Concentrations, and Autoimmunity: A Focus on the Thyroid

Currently, there is a lack of understanding of why many patients with thyroid dysfunction remain symptomatic despite being biochemically euthyroid. Gastrointestinal (GI) health is imperative for absorption of thyroid-specific nutrients as well as thyroid function directly. This comprehensive narrative review describes the impact of what the authors have conceptualized as the “nutrient–GI–thyroid axis”. Compelling evidence reveals how gastrointestinal health could be seen as the epicenter of thyroid-related care given that: (1) GI conditions can lower thyroid-specific nutrients; (2) GI care can improve status of thyroid-specific nutrients; (3) GI conditions are at least 45 times more common than hypothyroidism; (4) GI care can resolve symptoms thought to be from thyroid dysfunction; and (5) GI health can affect thyroid autoimmunity. A new appreciation for GI health could be the missing link to better nutrient status, thyroid status, and clinical care for those with thyroid dysfunction.