Exogenous H2S initiating Nrf2/GPx4/GSH pathway through promoting Syvn1-Keap1 interaction in diabetic hearts

Excessive ROS accumulation contributes to cardiac injury in type 2 diabetes mellitus. Hydrogen sulfide (H2S) is a vital endogenous gasotransmitter to alleviate cardiac damage in diabetic cardiomyopathy (DCM). However, the underlying mechanisms remain unclear. In this study, we investigated the effects of NaHS administration in db/db mice via intraperitoneal injection for 20 weeks and the treatment of high glucose (HG), palmitate (PA) and NaHS in HL-1 cardiomyocytes for 48 h, respectively. H2S levels were decreased in hearts of db/db mice and HL-1 cardiomyocytes exposed to HG and PA, which were restored by NaHS. Exogenous H2S activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPx4)/glutathione (GSH) pathway, suppressed ferroptosis and mitigated mitochondrial apoptosis in db/db mice. However, these effects were abrogated after Nrf2 knockdown. NaHS treatment elevated the ubiquitination level of Kelch-like ECH-associated protein (Keap1) by preserving its E3 ligase synoviolin (Syvn1), resulting in Nrf2 nuclear translocation. H2S facilitated the sulfhydration of Syvn1-cys115 site, a post-translational modification. Transfecting Syvn1 C115A in cardiomyocytes exposed to HG and PA partially attenuated the effects of NaHS on Nrf2 and cell death. Our findings suggest that exogenous H2S regulates Nrf2/GPx4/GSH pathway by promoting the Syvn1-Keap1 interaction to reduce ferroptosis and mitochondrial apoptosis in DCM.

Effect of Baseline Characteristics on Hypoglycaemia Risk with Insulin Glargine 100 U/mL: Post Hoc Analysis of the BEYOND 7 Study

INTRODUCTION

BEYOND 7 demonstrated that a higher starting dose (0.3 U/kg) of insulin glargine 100 U/mL (Gla-100) is as safe as the standard starting dose (0.2 U/kg) in Chinese individuals with type 2 diabetes who had uncontrolled hyperglycaemia despite receiving oral antihyperglycaemic drugs. This post hoc analysis determined the effect of baseline characteristics on hypoglycaemia risk in these individuals.

METHODS

Participants from BEYOND 7 were assessed based on their age at baseline (< 60 vs. ≥ 60 years), duration of diabetes (< 10 vs. ≥ 10 years), glycated haemoglobin (HbA1c; < 9 vs. ≥ 9%) and fasting plasma glucose level (FPG; < 11 vs. ≥ 11 mmol/L). Endpoints included the proportion of participants with overall confirmed (≤ 3.9 mmol/L) and symptomatic hypoglycaemia, as well as the proportion of participants who achieved an HbA1c < 7% without hypoglycaemia, the time to first achievement of fasting blood glucose (FBG) < 7 mmol/L and the change in HbA1c from baseline between the two treatment arms in each of these subgroups.

RESULTS

The proportion of participants with overall confirmed (6.1-16.7%) or symptomatic hypoglycaemia (5.7-18.4%) or the proportion who achieved HbA1c < 7.0% without hypoglycaemia (23.6-47.4%) was similar between the two treatment arms in all subgroups, with the exception of participants with a baseline duration of diabetes ≥ 10 years who experienced more symptomatic hypoglycaemia if initiating Gla-100 at a dose of 0.3 versus 0.2 U/kg. Participants aged < 60 years with an HbA1c < 9% or ≥ 9% or a duration of diabetes of 2-10 years achieved an FBG < 7.0 mmol/L in a significantly shorter time with Gla-100 starting dose of 0.3 U/kg versus 0.2 U/kg (all p < 0.001). No significant differences were seen among the subgroups in terms of change from baseline in HbA1c.

CONCLUSIONS

Baseline age, duration of diabetes, HbA1c level and FPG level do not affect the risk of hypoglycaemia with a higher starting dose of Gla-100 versus its standard starting dose.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02836704.

Comparison of Clinical Efficacy and Safety of Metformin Sustained-Release Tablet (II) (Dulening) and Metformin Tablet (Glucophage) in Treatment of Type 2 Diabetes Mellitus

OBJECTIVES

This study investigated the clinical efficacy and safety of metformin hydrochloride sustained-release (SR) tablet (II) produced by Dulening and the original metformin hydrochloride tablet produced by Glucophage in the treatment of type 2 diabetes mellitus (T2DM).

METHODS

This randomized, open and parallel controlled clinical trial consecutively recruited a total of 886 patients with T2DM in 40 clinical centers between May 2016 and December 2018. These patients were randomly assigned to the Dulening group (n=446), in which patients were treated with Dulening metformin SR tablets, and the Glucophage group (n=440), in which patients were treated with Glucophage metformin tablets, for 16 weeks. The changes in the levels of glycated hemoglobin (HbAc1) and fasting blood glucose (FBG) as well as weight loss were compared between these two groups. Also, the overall incidence of adverse drug reactions (ADRs) and the incidence of ADR of the gastrointestinal system observed in patients of these two groups were also compared.

RESULTS

There were no significant differences in demographic and basal clinical characteristics between these two groups. The Dulening and Glucophage groups showed comparable levels of decrease in HbA1c levels, FBG and weight loss after 12-week treatment (all p>0.05). The Dulening group had a significantly lower overall incidence of ADRs as well as gastrointestinal ADR than the Glucophage group.

CONCLUSIONS

Metformin SR tablets (II) and the original metformin tablets exhibit similar therapeutic efficacy in the treatment of T2DM, but metformin SR tablets (II) has the significantly lower incidence of ADRs than the original metformin tablets.

Measurement of hydroxyproline in collagen with three different methods

Determination of the 4-hydroxy-l-proline (hydroxyproline) concentration may provide useful information for the diagnosis and prognosis of diseases caused by disorders of collagen metabolism. The objective of the present study was to apply liquid chromatography-mass spectrometry (LC-MS) to assess the hydroxyproline concentration. The hydroxyproline concentration in lung and liver tissues measured by LC-MS was compared with values obtained by a colorimetric method, as well as a fluorescence method using high-performance liquid chromatography (HPLC) from previous studies by our group. The determination of the hydroxyproline concentration by LC-MS was improved as compared with that using the colorimetric and HPLC methods, due to its simplicity, high sensitivity (pg level) and short separation time. These results suggested that utilizing the LC-MS method for measuring the hydroxyproline concentration would be advantageous for the diagnosis of diseases associated with abnormalities of collagen metabolism.