Apoptotic Ablation of Platelets Reduces Atherosclerosis in Mice With Diabetes.

OBJECTIVE: People with diabetes are at a significantly higher risk of cardiovascular disease, in part, due to accelerated atherosclerosis. Diabetic subjects have increased number of platelets that are activated, more reactive, and respond suboptimally to antiplatelet therapies. We hypothesized that reducing platelet numbers by inducing their premature apoptotic death would decrease atherosclerosis. Approach and Results: This was achieved by targeting the antiapoptotic protein Bcl-xL (B-cell lymphoma-extra large; which is essential for platelet viability) via distinct genetic and pharmacological approaches. In the former, we transplanted bone marrow from mice carrying the Tyr15 to Cys loss of function allele of Bcl-x (known as Bcl-xPlt20) or wild-type littermate controls into atherosclerotic-prone Ldlr+/- mice made diabetic with streptozotocin and fed a Western diet. Reduced Bcl-xL function in hematopoietic cells significantly decreased platelet numbers, exclusive of other hematologic changes. This led to a significant reduction in atherosclerotic lesion formation in Bcl-xPlt20 bone marrow transplanted Ldlr+/- mice. To assess the potential therapeutic relevance of reducing platelets in atherosclerosis, we next targeted Bcl-xL with a pharmacological strategy. This was achieved by low-dose administration of the BH3 (B-cell lymphoma-2 homology domain 3) mimetic, ABT-737 triweekly, in diabetic Apoe-/- mice for the final 6 weeks of a 12-week study. ABT-737 normalized platelet numbers along with platelet and leukocyte activation to that of nondiabetic controls, significantly reducing atherosclerosis while promoting a more stable plaque phenotype. CONCLUSIONS: These studies suggest that selectively reducing circulating platelets, by targeting Bcl-xL to promote platelet apoptosis, can reduce atherosclerosis and lower cardiovascular disease risk in diabetes. Graphic Abstract: A graphic abstract is available for this article.

A randomized controlled trial of metformin on left ventricular hypertrophy in patients with coronary artery disease without diabetes: the MET-REMODEL trial.

AIM: We tested the hypothesis that metformin may regress left ventricular hypertrophy (LVH) in patients who have coronary artery disease (CAD), with insulin resistance (IR) and/or pre-diabetes. METHODS AND RESULTS: We randomly assigned 68 patients (mean age 65 ± 8 years) without diabetes who have CAD with IR and/or pre-diabetes to receive either metformin XL (2000 mg daily dose) or placebo for 12 months. Primary endpoint was change in left ventricular mass indexed to height1.7 (LVMI), assessed by magnetic resonance imaging. In the modified intention-to-treat analysis (n = 63), metformin treatment significantly reduced LVMI compared with placebo group (absolute mean difference -1.37 (95% confidence interval: -2.63 to -0.12, P = 0.033). Metformin also significantly reduced other secondary study endpoints such as: LVM (P = 0.032), body weight (P = 0.001), subcutaneous adipose tissue (P = 0.024), office systolic blood pressure (BP, P = 0.022) and concentration of thiobarbituric acid reactive substances, a biomarker for oxidative stress (P = 0.04). The glycated haemoglobin A1C concentration and fasting IR index did not differ between study groups at the end of the study. CONCLUSION: Metformin treatment significantly reduced LVMI, LVM, office systolic BP, body weight, and oxidative stress. Although LVH is a good surrogate marker of cardiovascular (CV) outcome, conclusive evidence for the cardio-protective role of metformin is required from large CV outcomes trials.

Renal and Cardiovascular Effects of sodium-glucose cotransporter 2 (SGLT2) inhibition in combination with loop Diuretics in diabetic patients with Chronic Heart Failure (RECEDE-CHF): protocol for a randomised controlled double-blind cross-over trial.

INTRODUCTION: Type 2 diabetes (T2D) and heart failure (HF) are a frequent combination, where treatment options remain limited. There has been increasing interest around the sodium-glucose cotransporter 2 (SGLT2) inhibitors and their use in patients with HF. Data on the effect of SGLT2 inhibitor use with diuretics are limited. We hypothesise that SGLT2 inhibition may augment the effects of loop diuretics and the benefits of SGLT2 inhibitors may extend beyond those of their metabolic (glycaemic parameters and weight loss) and haemodynamic parameters. The effects of SGLT2 inhibitors as an osmotic diuretic and on natriuresis may underlie the cardiovascular and renal benefits demonstrated in the recent EMPA-REG study. METHODS AND ANALYSIS: To assess the effect of SGLT2 inhibitors when used in combination with a loop diuretic, the RECEDE-CHF (Renal and Cardiovascular Effects of SGLT2 inhibition in combination with loop Diuretics in diabetic patients with Chronic Heart Failure) trial is a single-centre, randomised, double-blind, placebo-controlled, cross-over trial conducted in a secondary care setting within NHS Tayside, Scotland. 34 eligible participants, aged between 18 and 80 years, with stable T2D and CHF will be recruited. Renal physiological testing will be performed at two points (week 1 and week 6) on each arm to assess the effect of 25 mg empagliflozin, on the primary and secondary outcomes. Participants will be enrolled in the trial for a total period between 14 and 16 weeks. The primary outcome will assess the effect of empagliflozin versus placebo on urine output. The secondary outcomes are to assess the effect of empagliflozin on glomerular filtration rate, cystatin C, urinary sodium excretion, urinary protein/creatinine ratio and urinary albumin/creatinine ratio when compared with placebo. ETHICS AND DISSEMINATION: Ethics approval was obtained by the East of Scotland Research Ethics Service. Results of the trial will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT03226457; Pre-results.

Metformin and its effects on myocardial dimension and left ventricular hypertrophy in normotensive patients with coronary heart disease (the MET-REMODEL study): rationale and design of the MET-REMODEL study.

Left ventricular hypertrophy (LVH) is a common and independent risk factor for cardiovascular events in patients with coronary artery disease (CAD). Controlling blood pressure is the standard approach to the management of LVH, but this is only partially effective as LVH also persists in normotensive patients. Apart from blood pressure (BP), other main risk factors associated with LVH are insulin resistance (IR) and central obesity. The diabetic medication, Metformin, reduces IR and aids weight loss and may therefore regress LVH. The MET REMODEL study will investigate the ability of Metformin to regress LVH in 64 patients with CAD. The MET-REMODEL trial is a single-center, phase IV, double blind, randomized, placebo-controlled trial to investigate the efficacy of Metformin in regression of the independent cardiac risk factor of LVH in patients with CAD who are insulin resistant. A minimum of 64 adults with a history of CAD with LVH and IR will be randomized into two groups to receive, either Metformin XL or placebo. The primary endpoint of this trial is to investigate any change in left ventricular mass index. Secondary endpoints include changes to insulin resistance measured using fasting insulin resistance index (FIRI), obesity, LV size, and function and improvement in endothelial function. A positive result will assist clinicians to identify a new mechanism for LVH regression by administering Metformin XL. This may also lead to investigating the mortality benefit of Metformin in patients with CAD and LVH.

Underutilization of IV nitrates in the treatment of acute heart failure.

Acute heart failure (AHF) is a growing public health concern with high inhospital mortality and costs. Clinical practice guidelines, underpinned by positive randomized controlled trials, recommend the early use of intravenous (IV) nitrates in the treatment of AHF. However, the "real-world" usage of IV nitrates has not been clearly defined. The objective of this study was to examine the use of IV nitrates in the treatment of AHF as recommended by clinical practice guidelines. A case-record analysis was conducted of all admissions with AHF at a large teaching hospital. Of the 81 AHF patients (mean age 77 ± 11, mean SBP 130 ± 27 mmHg) enrolled for this analysis, only 5 (6%) received IV nitrates at the time of AHF admission. Forty (49%, mean age 77 ± 11, mean SBP 131 ± 27 mmHg) of these 81 patients met the guideline criteria for suitability for IV nitrates and only 5 (12%) of these received them during this admission. Patients who received IV nitrates were more likely to have higher blood pressure and all had myocardial ischemia as a precipitant. Seventy-five (93%) of the total population received loop diuretics on admission. Overall, this study shows that loop diuretics remain the first-line therapy in AHF with little use of IV nitrates, despite recommendations from clinical practice guidelines.