Identification of Resistance to Exogenous Thyroxine in Humans

Transcriptomic and proteomic investigations identify PI3K-akt pathway targets for hyperthyroidism management in rats via polar iridoids from radix Scrophularia

High-polarity iridoids from Radix Scrophulariae (R. Scrophulariae) offer a range of benefits, including anti-inflammatory, antioxidant, antitumour, antibacterial, antiviral, and antiallergic effects. Although previous studies have indicated the potential of R. Scrophulariae for hyperthyroidism prevention and treatment, the specific active compounds involved and their mechanisms of action are not fully understood. This study explored the effects of high-polarity iridoid glycosides from R. Scrophulariae on hyperthyroidism induced in rats by levothyroxine sodium. The experimental design included a control group, a hyperthyroidism model group, and a group treated with iridoid glycosides. Serum triiodothyronine (T3) and thyroxine (T4) levels were quantified using an enzyme-linked immunosorbent assay (ELISA). Transcriptomic and proteomic analyses were applied to liver samples to identify differentially expressed genes and proteins. These analyses were complemented by trend analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The effectiveness of key factors was further examined through molecular biology techniques. ELISA results indicated a notable increase in T3 and T4 in the hyperthyroid rats, which was significantly mitigated by treatment with iridoid glycosides. Transcriptomic analysis revealed 6 upregulated and 6 downregulated genes in the model group, showing marked improvement following treatment. Proteomic analysis revealed changes in 30 upregulated and 50 downregulated proteins, with improvements observed upon treatment. The PI3K-Akt signalling pathway was investigated through KEGG enrichment analysis. Molecular biology methods verified the upregulation of Spp1, Thbs1, PI3K, and Akt in the model group, which was reversed in the treatment group. This study revealed that highly polar iridoids from R. Scrophulariae can modulate the Spp1 gene and Thbs1 protein via the PI3K-Akt signalling pathway, suggesting a therapeutic benefit for hyperthyroidism and providing a basis for drug development targeting this condition.

Analysis of the value and safety of thyroid-stimulating hormone in the clinical efficacy of patients with thyroid cancer

BACKGROUND

Thyroid cancer (TC) is a common malignant tumor in the endocrine system. In recent years, the incidence and recurrence rates of TC have been raising due to increasing work pressure and irregular lifestyles. Thyroid-stimulating hormone (TSH) is a specific parameter for thyroid function screening. This study aims to explore the clinical value of TSH in regulating the progression of TC, so as to find a breakthrough for the early diagnosis and treatment of TC.

AIM

To explore the value and safety of TSH in the clinical efficacy of patients with TC.

METHODS

75 patients with TC admitted to the Department of Thyroid and Breast Surgery of our hospital from September 2019 to September 2021 were selected as the observation group, and 50 healthy subjects were selected as the control group during the same period. The control group was treated with conventional thyroid replacement therapy, and the observation group was treated with TSH suppression therapy. The soluble interleukin (IL)-2 receptor (sIL-2R), IL-17, IL-35 levels, free triiodothyronine (FT₃), free tetraiodothyronine (FT₄), CD3⁺, CD4⁺, CD8⁺, CD44V6, and tumor supplied group of factor (TSGF) levels were observed in the two groups. The occurrence of adverse reactions was compared between the two groups.

RESULTS

After treatment with different therapies, the levels of FT₃, FT₄, CD3⁺, and CD4⁺ in the observation group and the control group were higher than those before treatment, while the levels of CD8⁺, CD44V6, and TSGF were lower than those before treatment, and the differences were statistically significant (P < 0.05). More importantly, the levels of sIL-2R and IL-17 in the observation group were lower than those in the control group after 4 wk of treatment, while the levels of IL-35 were higher than those in the control group, and the differences were statistically significant (P < 0.05). The levels of FT₃, FT₄, CD3 ⁺, and CD4 ⁺ in the observation group were higher than those in the control group, and the levels of CD8⁺, CD44V6, and TSGF were lower than those in the control group. There was no significant difference in the overall incidence rate of adverse reactions between the two groups (P > 0.05).

CONCLUSION

TSH suppression therapy can improve the immune function of patients with TC, lower the CD44V6 and TSGF levels, and improve serum FT₃ and FT₄ levels. It demonstrated excellent clinical efficacy and a good safety profile.

Stochastic epigenetic mutations as possible explanation for phenotypical discordance among twins with congenital hypothyroidism

PURPOSE

The elevated frequency of discordance for congenital hypothyroidism (CH) phenotype between monozygotic twins suggests the involvement of non-mendelian mechanisms. The aim of the study was to investigate the role of epigenetics in CH pathogenesis.

METHODS

A genome-wide DNA methylation analysis was performed on the peripheral blood of 23 twin pairs (10 monozygotic and 13 dizygotic), 4 concordant and 19 discordant pairs for CH at birth.

RESULTS

Differential methylation analysis did not show significant differences in methylation levels between CH cases and controls, but a different methylation status of several genes may explain the CH discordance of a monozygotic twin couple carrying a monoallelic nonsense mutation of DUOX2. In addition, the median number of hypo-methylated Stochastic Epigenetic Mutations (SEMs) resulted significantly increased in cases compared to controls. The prioritization analysis for CH performed on the genes epimutated exclusively in the cases identified SLC26A4, FOXI1, NKX2-5 and TSHB as the genes with the highest score. The analysis of significantly SEMs-enriched regions led to the identification of two genes (FAM50B and MEG8) that resulted epigenetically dysregulated in cases.

CONCLUSION

Epigenetic modifications may potentially account for CH pathogenesis and explain discordance among monozygotic twins.

Tissue sensitivity to thyroid hormones may change over time

INTRODUCTION

Patients with congenital hypothyroidism (CH) may transiently show a certain degree of pituitary resistance to levothyroxine (LT4) which, however, normalizes subsequently. However, in some individuals, thyroid-stimulating hormone (TSH) fails to normalize despite adequate LT4 treatment.

METHODS

Nine patients with CH followed in three Academic Centre who developed over time resistance to thyroid hormones underwent extensive biochemical and genetic analyses. These latter were performed by Sanger sequence or targeted next-generation sequencing technique including a panel of candidate genes involved in thyroid hormone actions and congenital hypothyroidism (CH): THRA, THRB, DIO1, DIO2, SLC16A2, SECISBP2, DUOX2, DUOXA2, FOXE1, GLIS3, IYD, JAG1, NKX2-1, NKX2- 5, PAX8, SLC26A4, SLC5A5, TG, TPO, TSHR.

RESULTS

All patients displayed a normal sensitivity to thyroid hormone (TH) in the first years of life but developed variable degrees of resistance to LT4 treatment at later stages. In all cases, TSH normalized only in the presence of high free thyroxine levels. Tri-iodothyronine suppression test followed by thyrotrophin-releasing hormone stimulation was performed in two cases and was compatible with central resistance to THs. This biochemical feature was present independently on the cause of CH, being observed either in patients with an ectopic (n = 2) or eutopic gland (n = 3) or in case of athyreosis (n = 1). None of the patients had genetic variants in genes involved in the regulation of TH actions, while in two cases, we found two double heterozygous missense variants in TSHR and GLIS3 or in DUOX2 and SLC26A4 genes, respectively.

CONCLUSIONS

We report CH patients who showed an acquired and unexplainable pituitary refractoriness to TH action.

The influence of age and body weight on levothyroxine replacement dosage to achieve euthyroidism in patients with primary hypothyroidism

INTRODUCTION

Although, it is generally held that the levothyroxine (LT4) dose tends to decrease with age, this theory remains controversial. Our objective was to assess whether the LT4 dose required to achieve euthyroid status varies according to age, body weight (BW), sex, menopausal status, or antibody status.

MATERIALS AND METHODS

A cross-sectional study was performed from the retrospective review of the charts of patients with a previous diagnosis of primary hypothyroidism in treatment with LT4 and in a euthyroid state. Sex, age, actual body weight (ABW), TSH, and LT4 dose were recorded. Patients were grouped according to age ranges (18-44, 45-65, and over 65 years). A euthyroid state was defined as a serum TSH within the range of 0.4-4μIU/ml. A multiple linear regression model was performed to assess the LT4 dose and age, gender, antibody status, and ABW.

RESULTS

A total of 882 charts of patients were reviewed. 586 patients met the inclusion criteria. The median age was 55 years. There was no correlation between the LT4 dose and age. A positive correlation was observed between the LT4 dose and ABW, but not with the ideal BW. Linear regression analysis showed that positivity antibody and ABW have a significant effect on the LT4 dose. Comparison of the LT4 dose between the different age groups showed no difference.

CONCLUSION

Our study demonstrates that the dose of LT4 necessary to achieve euthyroidism is influenced by ABW and the presence of antibodies. Age and menopause did not influence the required daily dose of LT4.

The influence of age and body weight on levothyroxine replacement dosage to achieve euthyroidism in patients with primary hypothyroidism

INTRODUCTION

Although, it is generally held that the levothyroxine (LT4) dose tends to decrease with age, this theory remains controversial. Our objective was to assess whether the LT4 dose required to achieve euthyroid status varies according to age, body weight (BW), sex, menopausal status, or antibody status.

MATERIALS AND METHODS

A cross-sectional study was performed from the retrospective review of the charts of patients with a previous diagnosis of primary hypothyroidism in treatment with LT4 and in a euthyroid state. Sex, age, actual body weight (ABW), TSH, and LT4 dose were recorded. Patients were grouped according to age ranges (18-44, 45-65, and over 65 years). A euthyroid state was defined as a serum TSH within the range of 0.4-4μIU/ml. A multiple linear regression model was performed to assess the LT4 dose and age, gender, antibody status, and ABW.

RESULTS

A total of 882 charts of patients were reviewed. 586 patients met the inclusion criteria. The median age was 55 years. There was no correlation between the LT4 dose and age. A positive correlation was observed between the LT4 dose and ABW, but not with the ideal BW. Linear regression analysis showed that positivity antibody and ABW have a significant effect on the LT4 dose. Comparison of the LT4 dose between the different age groups showed no difference.

CONCLUSION

Our study demonstrates that the dose of LT4 necessary to achieve euthyroidism is influenced by ABW and the presence of antibodies. Age and menopause did not influence the required daily dose of LT4.