Clinical efficacy of selenium supplementation in patients with Hashimoto thyroiditis: A systematic review and meta-analysis.

BACKGROUND: Evidence suggests that selenium supplementation could be useful in the treatment of Hashimoto thyroiditis (HT), but the available trials are heterogeneous. This study investigates clinically relevant effects of selenium supplementation in patients with HT. METHODS: A systematic search was performed in PubMed, Web of Science, EMBASE, Scopus, and the Cochrane Library. The latest update was performed on December 3, 2022. We investigated the changes in thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibodies (TgAb) after selenium supplementation. The effect sizes were expressed as weighted mean difference (WMD) with 95% confidence intervals (CIs). RESULTS: After screening and full-text assessment, 7 controlled trials comprising 342 patients were included in the systematic review. The results showed that there was no significant change in TPOAb levels (WMD = -124.28 [95% CI: -631.08 to 382.52], P = .631, I2 = 94.5%) after 3 months of treatment. But there was a significant decrease in TPOAb levels (WMD = -284.00 [95% CI: -553.41 to -14.60], P < .05, I2 = 93.9%) and TgAb levels (WMD = -159.86 [95% CI: -293.48 to -26.24], P < .05, I2 = 85.3%) after 6 months of treatment. CONCLUSIONS: Selenium supplementation reduces serum TPOAb and TgAb levels after 6 months of treatment in patients with HT, but future studies are warranted to evaluate health-related quality or disease progression.

Effects of neferine on Kv4.3 channels expressed in HEK293 cells and ex vivo electrophysiology of rabbit hearts.

AIM: Neferine is an isoquinoline alkaloid isolated from seed embryos of Nelumbo nucifera (Gaertn), which has a variety of biological activities. In this study we examined the effects of neferine on Kv4.3 channels, a major contributor to the transient outward current (I(to)) in rabbit heart, and on ex vivo electrophysiology of rabbit hearts. METHODS: Whole-cell Kv4.3 currents were recorded in HEK293 cells expressing human cardiac Kv4.3 channels using patch-clamp technique. Arterially perfused wedges of rabbit left ventricles (LV) were prepared, and transmembrane action potentials were simultaneously recorded from epicardial (Epi) and endocardial (Endo) sites with floating microelectrodes together with transmural electrocardiography (ECG). RESULTS: Neferine (0.1-100 µmol/L) dose-dependently and reversibly inhibited Kv4.3 currents (the IC50 value was 8.437 µmol/L, and the maximal inhibition at 100 µmol/L was 44.12%). Neferine (10 µmol/L) caused a positive shift of the steady-state activation curve of Kv4.3 currents, and a negative shift of the steady-state inactivation curve. Furthermore, neferine (10 µmol/L) accelerated the inactivation but not the activation of Kv4.3 currents, and markedly slowed the recovery of Kv4.3 currents from inactivation. Neferine-induced blocking of Kv4.3 currents was frequency-dependent. In arterially perfused wedges of rabbit LV, neferine (1, 3, and 10 µmol/L) dose-dependently prolonged the QT intervals and action potential durations (APD) at both Epi and Endo sites, and caused dramatic increase of APD10 at Epi sites. CONCLUSION: Neferine inhibits Kv4.3 channels likely by blocking the open state and inactivating state channels, which contributes to neferine-induced dramatic increase of APD10 at Epi sites of rabbit heart.

Pharmacological enhancement of cardiac gap junction coupling prevents arrhythmias in canine LQT2 model.

Gap junctions contribute to the transmural heterogeneity of repolarization in the normal heart and under conditions of prolonged QT interval in the diseased heart. This study examined whether enhancing of gap junction coupling can reduce transmural dispersion of repolarization (TDR) and prevent torsade de pointes (TdP) in a canine LQT2 model. Canine left ventricular wedge preparations were perfused with delayed rectifier potassium current (IKr) blocker d-sotalol to mimic LQT2 and the antiarrhythmic peptide 10 (AAP10) was used as a gap junction coupling enhancer. As compared with the control group, the LQT2 group had significantly augmented TDR and higher incidence of TdP associated with increased nonphosphorylated connexin 43 (Cx43). AAP10 prevented augmentation of TDR and induction of TdP while rescuing Cx43 phosphorylation. There was no significant change in the quantity and spatial distribution of Cx43. These data indicate that gap junction enhancer AAP10 can prevent augmentation of TDR and suppress TdP by preventing dephosphorylation of Cx43 in a LQT2 model.