Dapagliflozin administration to a mouse model of type 2 diabetes induces DNA methylation and gene expression changes in pancreatic islets.

Decreased pancreatic ß-cell volume is a serious problem in patients with type 2 diabetes mellitus, and there is a need to establish appropriate treatments. Increasingly, sodium/glucose cotransporter 2 (SGLT2) inhibitors, which have a protective effect on pancreatic ß-cells, are being prescribed to treat diabetes; however, the underlying mechanism is not well understood. We previously administered SGLT2 inhibitor dapagliflozin to a mouse model of type 2 diabetes and found significant changes in gene expression in the early-treated group, which led us to hypothesize that epigenetic regulation was a possible mechanism of these changes. Therefore, we performed comprehensive DNA methylation analysis by methylated DNA immunoprecipitation using isolated pancreatic islets after dapagliflozin administration to diabetic model mice. As a result, we identified 31 genes with changes in expression due to DNA methylation changes. Upon immunostaining, cystic fibrosis transmembrane conductance regulator and cadherin 24 were found to be upregulated in islets in the dapagliflozin-treated group. These molecules may contribute to the maintenance of islet morphology and insulin secretory capacity, suggesting that SGLT2 inhibitors' protective effect on pancreatic ß-cells is accompanied by DNA methylation changes, and that the effect is long-term and not temporary. In future diabetes care, SGLT2 inhibitors may be expected to have positive therapeutic effects, including pancreatic ß-cell protection.

Analysis of thyroid function in Japanese patients with coronavirus disease 2019.

Thyroid dysfunction that is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is becoming increasingly recognized. However, only a few reports in Japan have addressed this issue to date. In this study, we sought to clarify whether infection with SARS-CoV-2 affected thyroid hormone levels and whether these hormones could be better predictors of prognosis in patients with coronavirus disease 2019 (COVID-19). Accordingly, we retrospectively examined 147 cases wherein thyroid hormones were measured at the time of admission among 848 Japanese patients with COVID-19 admitted to the Hyogo Prefectural Kakogawa Medical Center. All patients underwent thyroid function testing upon hospital admission. More than half (59.1%) of the patients were euthyroid. Twenty-four percent of patients had serum thyroid-stimulating hormone (TSH) levels lower than the reference range with normal serum free thyroxine (fT4) levels, and 3.4% of the patients had low TSH with high fT4 levels. Over 70% of the patients with moderate and severe COVID-19 had low serum free triiodothyronine (fT3) levels. Serum TSH and fT3 levels were inversely correlated with disease severity. The mortality rate in patients with low serum fT3 levels was significantly higher than that in those with normal serum fT3 levels.