Mechanistic insights regarding the role of SGLT2 inhibitors and GLP1 agonist drugs on cardiovascular disease in diabetes

The treatment landscape for patients with established or at high risk for cardiovascular disease and type 2 diabetes mellitus has entirely changed over the past decade, with the introduction of several anti-hyperglycemic agents. Sodium-glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP-1) agonists are two anti-hyperglycemic classes which have been of special interest after multiple large cardiovascular disease (CVD) outcomes studies have demonstrated superiority of these agents compared to placebo for major adverse CVD events and in some cases, hospitalization for heart failure. Despite the dramatic results of these trials, only recently have we began to understand the mechanisms underlying these CVD benefits. Here we review the underlying mechanisms which have the greatest plausibility for both of these agents including the impact of ventricular loading conditions, direct effects on cardiac structure and function, myocardial energetics and sodium/hydrogen exchange for SGLT2 inhibitors, and the anti-atherosclerotic, anti-inflammatory, and modulation of endothelial function for GLP-1 agonists.

The role of sodium glucose cotransporter-2 (SGLT-2) inhibitors in heart failure and chronic kidney disease in type 2 diabetes

Background: Heart failure (HF) and chronic kidney disease (CKD) are responsible for substantial morbidity and mortality in individuals with type 2 diabetes (T2D). Methods: This review discusses the significance of these comorbidities of T2D and current options for managing them, with a focus on sodium-glucose cotransporter-2 (SGLT-2) inhibitors. Based on a focused literature search of cardiovascular outcomes trials (CVOTs), this review assessed the effects of SGLT-2 inhibitors in individuals with T2D with or without established cardiovascular disease (CVD). Results: In addition to effective glycemic control and weight loss, SGLT-2 inhibitor treatment of T2D prevents adverse cardiovascular and renal outcomes in individuals with and without these comorbidities. Reduced rate of hospitalization due to HF (HHF) and improved renal outcomes appear to be class effects of SGLT-2 inhibitors. Reduction in CV events may be more significant in individuals with established cardiovascular disease. Conclusions: CVOTs and other studies confirm that the SGLT-2 inhibitors, mostly used in combination with other glucose-lowering drugs, offer several clinical benefits beyond improved glycemic control. These include reducing HHF risk and improving renal outcomes. HF and renal benefits are observed in individuals with and without established CVD, which may simplify therapeutic selection. Ongoing SGLT-2 inhibitor CVOTs will help clarify the potential of these drugs to treat T2D comorbid with different forms of HF (HF with preserved vs reduced ejection fraction) and different degrees of renal dysfunction, and in individuals with T2D vs pre-diabetes or normal glucose metabolism.

Design of the Magnetic Resonance Imaging Evaluation of Mineralocorticoid Receptor Antagonism in Diabetic Atherosclerosis (MAGMA) Trial

Mineralocorticoid receptor (MR) activation plays an essential role in promoting inflammation, fibrosis, and target organ damage. Currently, no studies are investigating MR antagonism in patients with type 2 diabetes mellitus (T2DM) with chronic kidney disease, at high risk for cardiovascular complications, who are otherwise not candidates for MR antagonism by virtue of heart failure. Further, there is limited information on candidate therapies that may demonstrate differential benefit from this therapy. We hypothesized that MR antagonism may provide additional protection from atherosclerosis progression in higher-risk patients who otherwise may not be candidates for such a therapeutic approach. In this double-blind, randomized, placebo-controlled trial, subjects with T2DM with chronic kidney disease (≥ stage 3) will be randomized in a 1:1 manner to placebo or spironolactone (12.5 mg with eventual escalation to 25 mg daily over a 4-week period). The co-primary efficacy endpoint will be percentage change in total atheroma volume in thoracic aorta and left ventricular mass at 52 weeks in patients treated with spironolactone vs placebo. Secondary outcomes include 24-hour mean systolic blood pressure, central aortic blood pressure, and insulin resistance (HOMA-IR) at 6 weeks. A novel measure in the study will be changes in candidate miRNAs that regulate expression of NR3C2 (MR gene) as well as measuring monocyte/macrophage polarization in response to therapy with spironolactone. We envision that our strategy of simultaneously probing the effects of a drug combined with analysis of mechanisms of action and predictive response will likely provide key information with which to design event-based trials.

Diabetes for Cardiologists: Practical Issues in Diagnosis and Management

Diabetes mellitus (DM), a chronic metabolic disease characterized by hyperglycemia, is a profound cardiovascular (CV) risk factor. It compounds the effects of all other risk factors, leads to premature micro- and macrovascular disease, facilitates development of heart failure, worsens the clinical course of all CV diseases, and shortens life expectancy. Established DM, unrecognized DM, and dysglycemia that may progress to DM are all commonly present at the time of presentation of overt CV disease. Thus, CV specialists and trainees frequently treat patients with dysglycemia. The traditional and proven role of cardiologists in reducing the risk of macrovascular events in this population is through aggressive lipid and blood pressure treatment. However, a more proactive role in the detection and management of DM is likely to become increasingly important as the prevalence continues to increase and therapies continue to improve. The latter include antihyperglycemic therapies with proven cardiovascular safety profiles and CV event reduction properties not yet fully elucidated and not necessarily related to glycemic control. Accordingly, the purpose of this article is to (1) expand the interest of cardiologists in earlier stages of the natural history of DM, when prevention or early detection might help achieve greatest benefit; (2) highlight principles of optimal glycemic management, with an emphasis on add-on choices showing promising reduction of CV events and lacking CV adverse effects; and (3) encourage cardiologists to become proactive partners in the multidisciplinary care needed to ensure optimal lifelong vascular health in patients with, or who are at risk of, DM.