Increased glycemic variability results in abnormal differentiation of T cell subpopulation in type 2 diabetes patients.

AIMS: We aimed to investigate the association between glycemic variability (GV) and the abnormal differentiation of T-cell subpopulations in patients with type 2 diabetes mellitus (T2DM). METHODS: In total, 108 hospitalized patients with T2DM were enrolled and divided into two subgroups (normal glycemic excursion (NGE) and high glycemic excursion (HGE)) according to their mean amplitude of glycemic excursion (MAGE) level. The MAGE was evaluated via continuous glucose monitoring for 72 h consecutively. Flow cytometry was used to determine the proportions of T cell subpopulations. RESULTS: The T helper (Th) 1 cell/Th2 cell ratio was significantly higher, and the proportion of regulatory T cells (Tregs) was significantly lower in the NGE group than in the HGE group (all P < 0.05). After fully adjusting for confounders, the MAGE was positively associated with the Th1 cell/Th2 cell ratio (ß = 0.370; P = 0.009) and negatively associated with the proportion of Tregs (ß = -0.554; P = 0.001). CONCLUSION: The MAGE was an independent risk factor for abnormally high Th1 cell/Th2 cell ratio and proportion of Tregs. Abnormal differentiation of T cell subpopulations induced by GV may impair ß-cell function, aggravate insulin resistance, and contribute to the development of diabetic complications.

Hypothyroidism is a causal determinant of age-related cataract risk in European population: a Mendelian randomization study.

Objective: To determine whether there is a causal relationship between thyroid dysfunction and the risk of age-related cataract (ARC) in the European population. Design: A two-sample Mendelian randomization (MR) study. Methods: Hypothyroidism, hyperthyroidism, free thyroxine (fT4), and thyrotropin (TSH) were selected as exposures. The single nucleotide polymorphisms (SNP) of hypothyroidism and hyperthyroidism were obtained from the genome-wide association studies (GWAS) of the IEU database, including 337,159 subjects. Data for fT4 and TSH (72,167 subjects) were extracted from the ThyroidOmics Consortium. ARC was used as the outcome. The SNPs associated with ARC were selected from a GWAS of 216,362 individuals in the FinnGen database. The main method used was the inverse variance-weighted method, together with four complementary methods. Sensitivity analyses were performed using Cochran's Q test, MR-PRESSO, MR-Egger regression and leave-one-out test. MR pleiotropy was used to test for pleiotropy. MR Steiger test was used to test for the directionality. Results: Two-sample MR analysis revealed a positive association between genetically predicted hypothyroidism and risk of ARC (OR = 2.501, 95% CI: 1.325-4.720; P = 0.004). Hyperthyroidism, circulating fT4 and TSH levels did not have a significant causal effect on ARC (P > 0.05). The results were robust and reliable, and no horizontal pleiotropy was found after sensitivity analyses. In the MR Steiger test, we found no reverse causal effects of hypothyroidism on the ARC (P <0.001). Conclusions: Our study provides strong evidence that hypothyroidism is a causal determinant of ARC risk.

Induced Overexpression of B Cell-Activating Factor by Triiodothyronine Results in Abnormal B Cell Differentiation in Mice.

Breakdown of tolerance and abnormal activation in B cells is an important mechanism in the pathogenesis of Graves' disease (GD) and high levels of thyroid hormones (THs) can drive the progression of GD. However, the interactions between THs and abnormal activation of B cells in the context of GD are not well understood. The aim of this study was to investigate B cell-activating factor (BAFF) mediating the cross talk between THs and B cells and the possible underlying mechanisms. A high-level triiodothyronine (T3) mouse model was used to verify T3-mediated induction of overexpression of BAFF and B cell abnormal differentiation. The possible promotion of BAFF overexpression in the mice spleen macrophages during polarization to M1 by T3 was also studied. We showed that high levels of T3 can induce BAFF overexpression and lead to abnormal differentiation of B cells in the mice. While the overexpression of BAFF was observed across many tissue types in the mice, high levels of T3 could induce M1 macrophages polarization by IFN (interferon-gamma)-γ in the spleen of the mice, which in turn generated BAFF overexpression. Our findings provide a novel insight into the interactions between the endocrine and immune systems, as well as provide insight into the role of TH in the pathogenesis of GD.

Effects of Glycemic Variability on Regulatory T Cells in Patients with Type 2 Diabetes and Kidney Disease.

Purpose: To investigate the pathogenesis of diabetic kidney disease (DKD) in type 2 diabetes mellitus (T2DM), we evaluated the effects of short-term glycemic variability (GV) on the profile of T cell subpopulations. Methods: A total of 47 T2DM patients with normoalbuminuria, 47 microalbuminuria, and 49 macroalbuminuria were enrolled. The continuous glucose monitoring (CGM) determined the GV of enrolled patients. Flow cytometry was used to determine the proportion of T cell subpopulations. Results: The frequency of T helper (Th) 17 and Th1 cells significantly increased while regulatory T cells (Tregs) significantly decreased in the macroalbuminuria group compared to normoalbuminuria and microalbuminuria groups (P < 0.01). The suppressive function of Tregs was significantly lower in the macroalbuminuria group than the normoalbuminuria group (P < 0.05). Compared with the normoalbuminuria group, the mean amplitude of glucose excursions (MAGE) of the macroalbuminuria group was significantly higher (P<0.05). Furthermore, there were negative associations between the proportion of Tregs and MAGE. Conclusions: Increased GV could decrease the proportion of Tregs and may impair their function. This may lead to increases in Th1 and Th17 cells, and some inflammatory cytokines, which might contribute to the development and progression of DKD in T2DM.

High triiodothyronine levels induce myocardial hypertrophy via BAFF overexpression.

Activated B cells contribute to heart diseases, and inhibition of B-cell activating factor (BAFF) expression is an effective therapeutic target for heart diseases. Whether activated B cells participate in the development and progression of hyperthyroid heart disease, and what induces B cells activation in hyperthyroidism are unknown. The present study aimed to determine the roles of BAFF overexpression induced by high concentrations of triiodothyronine (T3) in the pathogenesis of hyperthyroid heart disease. Female C57BL/6J mice were subcutaneously injected with T3 for 6 weeks, and BAFF expression was inhibited using shRNA. Protein and mRNA expression of BAFF in mouse heart tissues evaluated via immunohistochemistry, western blotting and polymerase chain reaction (PCR). Proportions of B cells in mouse cardiac tissue lymphocytes were quantified via flow cytometry. Morphology and left ventricle function were assessed using pathological sections and echocardiography, respectively. Here, we demonstrate that compared with the control group, the proportion of myocardial B cells was larger in the T3 group; immunohistochemistry, western blotting and PCR analyses revealed increased protein and mRNA expression levels of TNF-α and BAFF in heart tissues of the T3 group. Compared with the normal controls group, in the T3 group, the diameter of myocardial cells and some echocardiographic values significantly increased and hypertrophy and structural disorder were noticeable. Our results revealed that elevated levels of circulating T3 can promote the expression of BAFF in myocardial cells and can lead to B-cell activation, an elevated inflammatory response and ventricular remodelling.

The plasma levels of atrial natriuretic peptide and brain natriuretic peptide in type 2 diabetes treated with sodium-glucose cotransporter-2 inhibitor.

PURPOSE: The aim of this study was to determine the levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) after treatment with sodium-glucose cotransporter-2 (SGLT2) inhibitor or dipeptidyl peptidase-4 (DPP4) inhibitor in patients with type-2 diabetes inadequately controlled by insulin, and to determine whether variation in ANP levels can explain favorable cardiovascular outcome. METHODS: We enrolled 56 patients, aged 18-80years, with type-2 diabetes inadequately controlled by insulin: i.e., HbA1c level 7.5-10.5% despite at least 8weeks' injectable insulin at a stable mean dose of 20-150IU daily, with or without no more than two oral antidiabetic agents. FINDINGS: The 56 patients were randomized between 3 treatment groups: SGLT2 inhibitor (n=18), DPP4 inhibitor (n=19) and placebo (n=19). Patients who received SGLT2 inhibitor or DPP4 inhibitor treatment all showed significantly lower HbA1c levels, fasting blood glucose (FBG) levels and systolic blood pressure at 24weeks than controls. SGLT2 inhibitor treatment decreased ANP levels, BNP levels, systolic blood pressure and weight compared with placebo. Compared to those receiving DPP4 inhibitor, patients receiving SGLT2 inhibitor showed lower HbA1c levels (7.01 vs. 7.58%; P=0.03), ANP levels (28.41 vs. 43.03 pg/mL; P=0.00) and weight (66.14 vs. 71.76 kg; P=0.04) at 24weeks after adjusting for baseline values. The SGLT2 inhibitor group showed higher sodium concentrations than the placebo and DPP4 inhibitor groups (145.89 vs. 143.89 and 144.79 mmol/L, respectively; P=0.00 and P=0.04) at 24 weeks. ANP and BNP levels did not significantly correlate with HbA1c and blood glucose levels. IMPLICATIONS: These results indicated that SGLT2 inhibitors may be superior to DPP4 inhibitors in reducing risk of cardiovascular disease in diabetic patients. The major study limitation was the small number of patients per group, which should be enlarged in further research.