Vitamin D effects and endocrine diseases

Vitamin D3 attenuates autoimmune thyroiditis by regulating Th17/Treg cell differentiation via YAP/JAK1/STAT1 axis

BACKGROUND

Autoimmune thyroiditis (AITD) is an organ-specific autoimmune disease. Substantial evidence suggests that Vitamin D (VitD) deficiency is closely associated with an increased risk of AITD. However, the effects of VitD3 on immune cells, especially Th17/Treg cell subsets, and the underlying molecular mechanism in AITD have not yet been investigated.

METHODS

An experimental autoimmune thyroiditis (EAT) mouse model was established with a high-iodine diet. After 8 weeks, thyroid injury was assessed using hematoxylin and eosin (H&E) staining. ELISA was employed to measure serum levels of thyroxine (T3 and T4), thyroid autoimmune antibodies (Tg-Ab and TPO-Ab), and inflammatory cytokines. Flow cytometry and multiplex fluorescence immunohistochemical (mIHC) assays were used to analyze Th17/Treg cell subsets. The CCK-8 and flow cytometry assays were used to determine cell viability and apoptosis.

RESULTS

Administration of VitD3 reduced thyroid follicle destruction, decreased lymphocyte infiltration, and lowered T3, T4, Tg-Ab, and TPO-Ab serum levels in EAT mice. VitD3 treatment also reduced the frequency of Th17 cells while promoting the Treg cell subset both in the thyroid tissue and in the splenocytes cultured in vitro. Furthermore, VitD3 administration suppressed the production of inflammatory cytokines in EAT mice. VitD3 was also found to regulate Treg cells' differentiation, viability, and apoptosis. Mechanistically, we discovered that VitD3 treatment upregulated YAP expression and activated the JAK/STAT pathway. Rescue assays confirmed that depletion of YAP counteracted the effects of VitD3 on Treg cell differentiation and function.

CONCLUSION

Vitamin D3 attenuates AITD by modulating Th17/Treg cell balance via regulating the YAP/JAK1/STAT1 axis.

Multifaceted Roles of Vitamin D for Diabetes: From Immunomodulatory Functions to Metabolic Regulations

Numerous studies have established associations between vitamin D and diabetes. The vitamin D receptor is widely distributed throughout the human body, including in pancreatic beta cells (β-cells), hepatocytes, and immune cells. Therefore, vitamin D's effect on the risk, progression, or complications of diabetes may be mediated through various mechanisms. These include the regulation of insulin secretion or sensitivity and modulation of β-cell function and its immunomodulatory and anti-inflammatory effects. This review extensively explores the relationship between vitamin D status and diabetes, as well as the preventive or therapeutic effects of vitamin D supplementation on diabetes from human studies. Additionally, it examines in detail the impact of vitamin D on immune and inflammatory responses in the diabetic milieux and β-cell function to better understand the underlying mechanisms through which vitamin D influences diabetes.

Diagnostic workup of endocrine dysfunction in recurrent pregnancy loss: a cross-sectional study in Northeast China

Objective

To evaluate the prevalence of abnormal endocrine dysfunction for recurrent pregnancy loss (RPL) amongst patients with two versus three or more pregnancy losses.

Methods

This cross-sectional study retrospectively collected pre-pregnancy data of 537 women diagnosed with RPL in Shengjing Hospital of China Medical University from 2017 to 2022, including the baseline data of patients and the test results of endocrine factors. Several endocrine dysfunction included in this study were: thyroid dysfunction, obesity, hyperprolactinemia, polycystic ovary syndrome and blood glucose abnormality. Furthermore, vitamin D level were collected to study its relationship with endocrine dysfunction. Finally, we subdivided the patients according to the number of previous pregnancy loss and compared the prevalence of endocrine dysfunction between subgroups.

Results

Among 537 RPL patients, 278 (51.8%) patients had abnormal endocrine test results. The highest incidence of endocrine dysfunction was thyroid dysfunction (24.39%, 131/537), followed by hyperprolactinemia (17.34%, 85/490), obesity (10.8%, 58/537), polycystic ovary syndrome (10.50%, 56/533), and abnormal blood glucose (5.29%, 27/510). Only 2.47%(13/527) of patients have vitamin D level that reach the standard. After subdividing the population according to the number of pregnancy loss, we did not find that the incidence of endocrine dysfunction (P=0.813), thyroid dysfunction (P=0.905), hyperprolactinemia (P=0.265), polycystic ovary syndrome (P=0.638), blood glucose abnormality (P=0.616) and vitamin D deficiency (P=0.908) were different among patients with two versus three or more pregnancy losses. However, obesity (P=0.003) was found more frequently observed in patients with more times of pregnancy loss.

Conclusion

The prevalence of endocrine dysfunction in RPL population is high. There is no difference in the prevalence of endocrine dysfunction, except for obesity, among patients with two or more pregnancy losses, which may suggest investigations of endocrine dysfunction when patients have two pregnancy losses.