Chronic O-GlcNAcylation and Diabetic Cardiomyopathy: The Bitterness of Glucose

Type 2 diabetes (T2D) is a major risk factor for heart failure. Diabetic cardiomyopathy (DC) is characterized by diastolic dysfunction and left ventricular hypertrophy. Epidemiological data suggest that hyperglycaemia contributes to the development of DC. Several cellular pathways have been implicated in the deleterious effects of high glucose concentrations in the heart: oxidative stress, accumulation of advanced glycation end products (AGE), and chronic hexosamine biosynthetic pathway (HBP) activation. In the present review, we focus on the effect of chronic activation of the HBP on diabetic heart function. The HBP supplies N-acetylglucosamine moiety (O-GlcNAc) that is O-linked by O-GlcNAc transferase (OGT) to proteins on serine or threonine residues. This post-translational protein modification modulates the activity of the targeted proteins. In the heart, acute activation of the HBP in response to ischaemia-reperfusion injury appears to be protective. Conversely, chronic activation of the HBP in the diabetic heart affects Ca2+ handling, contractile properties, and mitochondrial function and promotes stress signaling, such as left ventricular hypertrophy and endoplasmic reticulum stress. Many studies have shown that O-GlcNAc impairs the function of key protein targets involved in these pathways, such as phospholamban, calmodulin kinase II, troponin I, and FOXO1. The data show that excessive O-GlcNAcylation is a major trigger of the glucotoxic events that affect heart function under chronic hyperglycaemia. Supporting this finding, pharmacological or genetic inhibition of the HBP in the diabetic heart improves heart function. In addition, the SGLT2 inhibitor dapagliflozin, a glucose lowering agent, has recently been shown to lower cardiac HBP in a lipodystophic T2D mice model and to concomitantly improve the diastolic dysfunction of these mice. Therefore, targeting cardiac-excessive O-GlcNAcylation or specific target proteins represents a potential therapeutic option to treat glucotoxicity in the diabetic heart

Association of Patient Profile with Glycemic Control and Hypoglycemia with Insulin Glargine 300 U/mL in Type 2 Diabetes: A Post Hoc Patient-Level Meta-Analysis

ABSTRACT Aims: To examine the association of baseline patient characteristics with study outcomes in people with type 2 diabetes receiving insulin glargine 300 U/mL (Gla-300) versus glargine 100 U/mL (Gla-100), over a 6-month period. Methods: A post hoc patient-level metaanalysis using data from three multicenter, randomized, open-label, parallel-group, phase 3a studies of similar design, in people previously receiving either basal and prandial insulin, basal insulin ? oral antihyperglycemic drugs, or no prior insulin (EDITION 1, 2 and 3, respectively). The endpoints, glycated hemoglobin (HbA1c), hypoglycemia, body weight change, and insulin dose were investigated by subgroups: age (\65 and C 65 years), body mass index (BMI; \ 30 and C 30 kg/m2), age at onset (\40, 40–50, and [ 50 years), and diabetes duration (\ 10 and C 10 years). Results: Reduction in HbA1c was comparable between insulins, regardless of subgroup. The lower risk of C 1 nocturnal (00:00–05:59 h) confirmed (B 3.9 mmol/L [B 70 mg/dL]) or severe hypoglycemic event with Gla-300 versus Gla-100 was also unaffected by participant characteristics. While heterogeneity of treatment effect between diabetes duration subgroups was seen for the risk of C 1 confirmed (B 3.9 mmol/L [B 70 mg/dL]) or severe hypoglycemic event at any time (24 h), treatment effect consistently favored Gla-300; no evidence of heterogeneity was observed for the other subgroups. Annualized rates of confirmed (B 3.9 mmol/L [B 70 mg/dL]) or severe hypoglycemia and body weight change were not influenced by participant characteristics; a similar pattern was observed with insulin dose. Conclusions: Comparable glycemic control was observed with Gla-300 versus Gla-100, with less hypoglycemia, regardless of age, BMI, age at onset or diabetes duration. Funding: Sanofi. Plain Language Summary: Plain language summary available for this article. Keywords: Glycated Hemoglobin A; Hypoglycemia; Insulin Glargine; Type 2 Diabetes PLAIN LANGUAGE SUMMARY Treatments for patients with type 2 diabetes aim to reduce the levels of blood glucose and can include injections with insulin. However, care must be taken to prevent blood glucose levels falling too low (a state called hypoglycemia). Previous studies have shown that insulin glargine 300 units/mL (Gla-300) provides similar reductions in blood glucose levels as insulin glargine 100 units/mL (Gla-100) but is less likely to cause hypoglycemia. However, different patients may respond differently to treatments depending on their individual clinical and biological characteristics. The aim of this study was to evaluate how different profiles of patients with type 2 diabetes responded to Gla-300 and Gla-100 injections. Patients were grouped by different ages, weights, age at diabetes diagnosis, and number of years since diagnosis of diabetes. We found that Gla-300 and Gla-100 reduced glycated hemoglobin (HbA1c; a marker of blood glucose control over the previous 2–3 months) similarly, regardless of how patients were grouped. However, patients treated with Gla-300 were less likely to experience hypoglycemia than those treated with Gla-100, and this association was also true regardless of different patient characteristics. We therefore concluded that Gla-300 is an effective and safe treatment in patients with type 2 diabetes, regardless of their age, weight, age at diabetes diagnosis, and years since diagnosis

Effect of alirocumab on individuals with type 2 diabetes, high triglycerides, and low high-density lipoprotein cholesterol

Background Mixed dyslipidemia [elevated non-high-density lipoprotein cholesterol (non-HDL-C) and triglycerides (TGs), and decreased HDL-C] is common in type 2 diabetes mellitus (T2DM) and is associated with increased cardiovascular risk. Non-HDL-C and apolipoprotein B (ApoB) are the preferred therapeutic targets for mixed dyslipidemia. Alirocumab is a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9) that effectively reduces low-density lipoprotein cholesterol (LDL-C), non-HDL-C, ApoB, and lipoprotein(a) (Lp[a]), and is well-tolerated in individuals with T2DM. Methods The previously reported open-label ODYSSEY DM-DYSLIPIDEMIA trial data demonstrated the effects of alirocumab on individuals with non‐HDL-C ≥ 100 mg/dL and TGs ≥ 150 and < 500 mg/dL receiving stable maximally tolerated statin (n = 413). This post hoc subgroup analysis of the primary trial investigated the effects of alirocumab [75 mg every 2 weeks (Q2W) with possible increase to 150 mg Q2W at Week 12] versus usual care [ezetimibe, fenofibrate, or no additional lipid-lowering therapy (LLT)] on non-HDL-C and other lipids in individuals with T2DM and baseline TGs ≥ 200 mg/dL and HDL-C < 40 mg/dL (men) or < 50 mg/dL (women). Results Alirocumab significantly reduced non-HDL-C [LS mean difference (standard error (SE)), − 35.0% (3.9)], ApoB [LS mean difference (SE), − 34.7% (3.6)], LDL-C [LS mean difference (SE), − 47.3% (5.2)], LDL particle number [LS mean difference (SE), − 40.8% (4.1)], and Lp(a) [LS mean difference (SE), − 29.9% (5.4)] versus usual care from baseline to Week 24 (all P < 0.0001). Results were similar for alirocumab versus usual care. TG reductions were similar between alirocumab and usual care (no significant difference), but greater with fenofibrate versus alirocumab (P = 0.3371). Overall, alirocumab significantly increased HDL-C versus usual care [LS mean difference (SE), 7.9% (3.6); P < 0.05], although differences with alirocumab versus ezetimibe or fenofibrate were non-significant. Most individuals receiving alirocumab achieved ApoB < 80 mg/dL (67.9%) and non-HDL-C < 100 mg/dL (60.9%). Adverse event frequency was similar between alirocumab (67.2%) and usual care (70.7%). Additionally, no clinically relevant effect of alirocumab on change in glycemic parameters or use of antihyperglycemic agents was observed. Conclusions Alirocumab is an effective therapeutic option for individuals with T2DM, TGs ≥ 200 mg/dL, and HDL-C < 40 mg/dL (men) or < 50 mg/dL (women). Atherogenic lipid (ApoB and non-HDL) reductions were greater with alirocumab than ezetimibe, fenofibrate, or no LLT. Consistent with previous studies, alirocumab was generally well tolerated. Trial registration Clinicaltrials.gov, NCT02642159. Registered December 24, 2015, https://clinicaltrials.gov/ct2/show/NCT0264215

Associations of microvascular complications with all-cause death in patients with diabetes and COVID-19:the CORONADO, ABCD Covid-19 audit and AMERICADO study groups

AIM: To provide a detailled analysis of the microvascular burden in patients with diabetes hopitalized for COVD‐19. MATERIALS AND METHODS: We analysed data from the French CORONADO initiative and the UK Association of British Clinical Diabetologists (ABCD) COVID‐19 audit, two nationwide multicentre studies, and the AMERICADO, a multicentre study conducted in New York area. We assessed the association between risk of all‐cause death during hospital stay and the following microvascular complications in patients with diabetes hospitalized for COVID‐19: diabetic retinopathy and/or diabetic kidney disease and/or history of diabetic foot ulcer. RESULTS: Among 2951 CORONADO, 3387 ABCD COVID‐19 audit and 9327 AMERICADO participants, microvascular diabetic complications status was ascertained for 1314 (44.5%), 1809 (53.4%) and 7367 (79.0%) patients, respectively: 1010, 1059 and 1800, respectively, had ≥1 severe microvascular complication(s) and 304, 750 and 5567, respectively, were free of any complications. The patients with isolated diabetic kidney disease had an increased risk of all‐cause death during hospital stay: odds ratio [OR] 2.53 (95% confidence interval [CI] 1.66‐3.83), OR 1.24 (95% CI 1.00‐1.56) and OR 1.66 (95% CI 1.40‐1.95) in the CORONADO, the ABCD COVID‐19 national audit and the AMERICADO studies, respectively. After adjustment for age, sex, hypertension and cardiovascular disease (CVD), compared to those without microvascular complications, patients with microvascular complications had an increased risk of all‐cause death during hospital stay in the CORONADO, the ABCD COVID‐19 diabetes national audit and the AMERICADO studies: adjusted OR ((adj)OR) 2.57 (95% CI 1.69‐3.92), (adj)OR 1.22 (95% CI 1.00‐1.52) and (adj)OR 1.33 (95% CI 1.15‐1.53), respectively. In meta‐analysis of the three studies, compared to patients free of complications, those with microvascular complications had an unadjusted OR for all‐cause death during hospital stay of 2.05 (95% CI 1.42‐2.97), which decreased to 1.62 (95% CI 1.19‐2.119) after adjustment for age and sex, and to 1.50 (1.12‐2.02) after hypertension and CVD were further added to the model. CONCLUSION: Microvascular burden is associated with an increased risk of death in patients hospitalized for COVID‐19

Alirocumab versus usual lipid-lowering care as add-on to statin therapy in individuals with type 2 diabetes and mixed dyslipidaemia:The ODYSSEY DM-DYSLIPIDEMIA randomized trial

Individuals with type 2 diabetes (T2DM) and mixed dyslipidaemia represent a high-risk and difficult-to-treat population. ODYSSEY DM-DYSLIPIDEMIA (NCT02642159) compared alirocumab, a proprotein convertase subtilisin-kexin type 9 inhibitor, with usual care (UC) in individuals with T2DM and mixed dyslipidaemia not optimally managed by maximally-tolerated statins

Identification of novel APOB mutations by targeted next-generation sequencing for the molecular diagnosis of familial hypobetalipoproteinemia

International audienceFamilial hypobetalipoproteinemia (FHBL) is a co-dominant disorder characterized by decreased plasma levels of LDL-cholesterol and apolipoprotein B (ApoB). Currently, genetic diagnosis in FHBL relies largely on Sanger sequencing to identify APOB and PCSK9 gene mutations and on western blotting to detect truncated ApoB species

Seipin localizes at endoplasmic-reticulum-mitochondria contact sites to control mitochondrial calcium import and metabolism in adipocytes

Deficiency of the endoplasmic reticulum (ER) protein seipin results in generalized lipodystrophy by incompletely understood mechanisms. Here, we report mitochondrial abnormalities in seipin-deficient patient cells. A subset of seipin is enriched at ER-mitochondria contact sites (MAMs) in human and mouse cells and localizes in the vicinity of calcium regulators SERCA2, IP3R, and VDAC. Seipin association with MAM calcium regulators is stimulated by fasting-like stimuli, while seipin association with lipid droplets is promoted by lipid loading. Acute seipin removal does not alter ER calcium stores but leads to defective mitochondrial calcium import accompanied by a widespread reduction in Krebs cycle metabolites and ATP levels. In mice, inducible seipin deletion leads to mitochondrial dysfunctions preceding the development of metabolic complications. Together, these data suggest that seipin controls mitochondrial energy metabolism by regulating mitochondrial calcium influx at MAMs. In seipin-deficient adipose tissue, reduced ATP production compromises adipocyte properties, contributing to lipodystrophy pathogenesis.Peer reviewe

No effect of PCSK9 inhibitor alirocumab on the incidence of diabetes in a pooled analysis from 10 ODYSSEY Phase 3 studies

AIMS: Statins have modest adverse effects on glycaemic control. Alirocumab, a proprotein convertase subtilisin/kexin type 9 inhibitor, lowers low-density lipoprotein cholesterol. This study assessed the effects of alirocumab on new-onset diabetes and pre-diabetes incidence in individuals without diabetes at baseline. METHODS AND RESULTS: Pooled analysis of 10 ODYSSEY Phase 3 trials (n = 4974) of 24–104 weeks duration. Six trials (n = 4211) were ≥52 weeks in length. Most patients received background maximally tolerated statin. Alirocumab effect on the rate of diabetes-related treatment-emergent adverse events (TEAEs), and/or fasting plasma glucose (FPG) and glycated haemoglobin A(1C) (HbA(1C)) was measured at baseline and every 12–24 weeks. Transition to diabetes analysis combined TEAE and FPG/HbA(1C) laboratory data. At baseline, 30.7% of individuals had diabetes and were excluded from the current analysis. The remaining 3448 individuals without diabetes had pre-diabetes (39.6%) or were normoglycaemic (29.7%). The hazard ratio (HR; 95% confidence interval) for diabetes-related TEAEs in alirocumab was 0.64 (0.36–1.14) vs. placebo and 0.55 (0.22–1.41) vs. ezetimibe. The HR associated for transition from pre-diabetes to new-onset diabetes for alirocumab was 0.90 (0.63–1.29) vs. placebo and 1.10 (0.57–2.12) vs. ezetimibe. Mean change in FPG/HbA(1C) over time showed no difference between treatment groups in patients without diabetes. CONCLUSIONS: There was no evidence of an effect of alirocumab on transition to new-onset diabetes in 3448 individuals without diabetes at baseline with a follow-up period of 6–18 months, compared to either placebo or ezetimibe. Longer follow-up with larger number of individuals is needed to conclusively rule out an effect

Sotagliflozin Added to Optimized Insulin Therapy Leads to Lower Rates of Clinically Relevant Hypoglycemic Events at Any HbA1c at 52 Weeks in Adults with Type 1 Diabetes

Background: Hypoglycemia rates usually increase when insulin treatment is intensified to improve glycemic control. We evaluated (post hoc) hypoglycemic rates in adult patients with type 1 diabetes (T1D) on sotagliflozin (a dual sodium-glucose cotransporter [SGLT] 1 and 2 inhibitor) in two phase 3, 52-week clinical trials (inTandem 1 and 2; NCT02384941 and NCT02421510). Materials and Methods: We analyzed rates of documented hypoglycemia (level 1, blood glucose 6554 to &lt;70\u2009mg/dL) and clinically important hypoglycemia (level 2, glucose &lt;54\u2009mg/dL) in a patient-level pooled analysis (n\u2009=\u20091362) using a negative binomial model adjusted for hemoglobin A1c (HbA1c) at 52 weeks in patients receiving placebo, sotagliflozin 200\u2009mg, and sotagliflozin 400\u2009mg. Results: Rates of level 1 hypoglycemia events per patient-year were 58.25 (95% confidence interval: 50.26-67.50) with placebo, 44.86 (38.83-51.82; P\u2009=\u20090.0138 vs. placebo) with sotagliflozin 200\u2009mg, and 45.68 (39.52-52.81; P\u2009=\u20090.0220) with sotagliflozin 400\u2009mg. Sotagliflozin was also associated with lower rates of level 2 hypoglycemia: 15.95 (14.37-17.70), 11.51 (10.39-12.76; P\u2009&lt;\u20090.0001), and 11.13 (10.03-12.35; P\u2009&lt;\u20090.0001) for placebo and sotagliflozin 200 and 400\u2009mg, respectively. The difference in rates of hypoglycemia with sotagliflozin versus placebo became more pronounced as HbA1c decreased. Conclusions: At week 52, level 1 and 2 hypoglycemia events were 22% to 30% less frequent with sotagliflozin added to optimized insulin therapy versus placebo in adults with T1D at any HbA1c level, with greater differences at lower HbA1c values. These findings support the use of sotagliflozin as an insulin adjunct in T1D