Cardiovascular Effects of Glucose-lowering Therapies for Type 2 Diabetes: New Drugs in Perspective

SGLT1: A Potential Drug Target for Cardiovascular Disease

SGLT1 and SGLT2 are the two main members of the sodium-glucose cotransporters (SGLTs), which are mainly responsible for glucose reabsorption in the body. In recent years, many large clinical trials have shown that SGLT2 inhibitors have cardiovascular protection for diabetic and non-diabetic patients independent of lowering blood glucose. However, SGLT2 was barely detected in the hearts of humans and animals, while SGLT1 was highly expressed in myocardium. As SGLT2 inhibitors also have a moderate inhibitory effect on SGLT1, the cardiovascular protection of SGLT2 inhibitors may be due to SGLT1 inhibition. SGLT1 expression is associated with pathological processes such as cardiac oxidative stress, inflammation, fibrosis, and cell apoptosis, as well as mitochondrial dysfunction. The purpose of this review is to summarize the protective effects of SGLT1 inhibition on hearts in various cell types, including cardiomyocytes, endothelial cells, and fibroblasts in preclinical studies, and to highlight the underlying molecular mechanisms of protection against cardiovascular diseases. Selective SGLT1 inhibitors could be considered a class of drugs for cardiac-specific therapy in the future.

Real-world evaluation of glucose-lowering therapies and the use of weight-adjusted variable rate intravenous insulin infusion in the management of hyperglycaemia in patients with acute coronary syndrome (REGULATE-ACS)

INTRODUCTION

Admission hyperglycaemia in acute coronary syndromes (ACS) is a strong independent predictor of adverse clinical outcomes post-ACS. We examined the safety, efficacy, and feasibility of a modified, weight-adjusted variable rate intravenous insulin infusion (VRIII) and evaluated current practice of prescribing novel cardio-protective glucose-lowering therapies in patients presenting with acute hyperglycaemia across the ACS spectrum.

METHODS

REGULATE-ACS was an observational single-centre study of consecutive patients admitted with acute hyperglycaemia post-ACS between 2020 and 2021. Following updated local guidance on a modified VRIII, we evaluated its safety and efficacy in glycaemic control, cardio-metabolic complications including hypoglycaemia (blood glucose <3 mmol/L) and 30-day mortality. We also determined the prescription of glucose-lowering therapies pre-discharge.

RESULTS

Out of 107 patients, mean age was 64.9 ± 12.2 years, 82% had known diabetes, and 15% newly diagnosed diabetes. 86.9% (n = 93) had an admission glucose ≥11 mmol/L. In patients treated with VRIII (n = 63/93, 67.7%), glucose improved from 17.5 to 9.0 mmol/L (IQR 7.1-12.1), which was 3 mmol/L lower (p = 0.03) than in patients not treated with VRIII (n = 30/93, 32.3%) where median glucose reduced from 12.6 to 12 mmol/L (IQR 8.6-13.9). No significant hypoglycaemia, arrhythmia or worsening pulmonary oedema associated with VRIII was found. Novel glucose-lowering therapies were initiated in 20/71 (28.2%) and 3/15 (20.0%) of patients with prior and newly diagnosed diabetes, respectively.

CONCLUSION

This real-world analysis provides further support of efficacy, safety, and feasibility of a modified, weight-adjusted VRIII in managing acute hyperglycaemia in ACS. Despite established cardio-protective benefits of novel glucose-lowering therapies, <1/3 of eligible patients received such agents pre-discharge, demanding further research and awareness.

Effect of semaglutide on coronary atherosclerosis progression in patients with type II diabetes: rationale and design of the semaglutide treatment on coronary progression trial

BACKGROUND

Cardiovascular morbidity and mortality are a major burden in patients with type 2 diabetic mellitus. In a landmark study, semaglutide (an injectable glucagon like peptide-1 receptor agonist) has been shown to significantly reduce cardiovascular events, however, the mechanism of benefit is still unknown. The primary hypothesis of our current study is to assess the effect of semaglutide to reduce progression of noncalcified coronary atherosclerotic plaque volume as measured by serial coronary CTA as compared to placebo in persons with diabetes over 1 year.

METHODS

One hundred forty patients will be enrolled after signing informed consent and followed up for 12 months and with a phone call 30 days after medical discontinuation. All the participants will undergo coronary artery calcium scoring and coronary computed tomography angiography at our center at baseline and 12 months. Eligible participants will be randomly assigned to semaglutide 2 mg/1.5 ml (1.34 mg/ml) prefilled pen for subcutaneous (SC) injection or placebo 1.5 ml, pen-injector for SC injection in a 1:1 fashion as add-on to their standard of care.

RESULTS

As of July 2019, the study was approximately 30% enrolled with an estimated enrollment completion by first quarter of 2020 and end of study by first quarter 2021. Thirty patients were enrolled as of 23 July 2019. Preliminary data of demographics and clinical characteristics were summarized.

CONCLUSION

Our current study will provide important imaging-derived data that may add relevance to the clinically derived outcomes from liraglutide effect and action in diabetes: evaluation of cardiovascular outcome results and semaglutide and cardiovascular outcomes in patients with type 2 diabetic mellitus 6 trials.

Efficacy of Liraglutide in clinical practice: Single centre experience

Background and Objective:

GLP-one receptor agonists are amongst the unique antidiabetes medications that have significant metabolic and cardiovascular benefits in addition to glucose lowering effect. To best of our knowledge, there is no published data on efficacy of liraglutide use among Pakistani population.Our objective was to ascertain the efficacy of liraglutide use among type two diabetes patients.

Methods:

This retrospective study was conducted at the Endocrinology Clinics of Aga Khan University Hospital (AKUH) Karachi, Pakistan during the period from July 01, 2016 to 30th June, 2017. Liraglutide was prescribed to 68 obese type two diabetes patients with uncontrolled diabetes taking more than one oral medication ± insulin. Starting dose of Liraglutide was 0.6 mg, which was increased to 1.2 mg after 1-2 weeks with further increment to 1.8 mg/day based on tolerance and individual patient preference. Dose of other diabetes medications was adjusted according to clinical judgment whereas Dipeptidyl peptidase-4(DPP-4) inhibitors were discontinued.

Results:

Mean age of cohort was 55 years (SD=10.94 years) with median body mass index of 36.45 kg/m² and majority (57.35%) were on a dose of 1.2 mg of Liraglutide per day. Median HbA₁c reduced to 7.50% and 7.40% at three months and six months respectively vs 8.45% at baseline. Mean reduction in weight after three month was two kilograms and at six months, it was 1.38 kilograms respectively.

Conclusion:

Liraglutide as add on therapy demonstrated favourable HbA1c and weight reduction in obese uncontrolled type two Diabetes Pakistani subjects.

Enhancement of glucose homeostasis through the PI3K/Akt signaling pathway by dietary with Agaricus blazei Murrill in STZ-induced diabetic rats

Agaricus blazei Murrill (ABM) is an edible fungus. This study investigated the protective role of ABM fruiting body against streptozotocin (STZ)-induced diabetic rats. After 4 weeks of ABM supplement, glucose homeostasis was improved in diabetic rats. Quantitative real-time and Western blot analyses suggested that ABM could promote the gene and protein expression level of insulin receptor, pyruvate dehydrogenase kinase, phospho-kinase B, kinase B, phosphatidylinositol 3-kinase, insulin receptor substrate 1, glucose transporter-4, and glutamine synthetase, while inhibiting the expression of glycogen synthase kinase 3β and c-jun N-terminal kinase 1 and 2. According to multivariate and univariate statistical analysis, liver metabolite profiles of the normal and diabetic rats fed basal and experimental diet were clearly separated. The differential liver metabolites from diabetic rats fed basal and ABM diet-related pathways including the glycolysis pathway, pentose phosphate pathway, tricarboxylic acid cycle, and oxidative phosphorylation were analyzed. A total of 18 potential biomarker metabolites were identified as differential biomarkers associated with ABM supplement diet.

Effect of Sodium-Glucose Cotransporter-2 Inhibitors versus Dipeptidyl Peptidase 4 Inhibitors on Cardiovascular Function in Patients with Type 2 Diabetes Mellitus and Coronary Artery Disease

Background

Randomized controlled trials demonstrated lowering risks of cardiovascular events with sodium-glucose cotransporter-2 (SGLT2) inhibitors in patients with type 2 diabetes mellitus (T2DM) and high cardiovascular risk. We analyzed the effects of cardiovascular function on SGLT2 inhibitors compared with dipeptidyl peptidase-4 (DPP4) inhibitors in T2DM with atherosclerotic cardiovascular disease (ASCVD) or heart failure (HF).

Methods

This is a retrospective, observational, single center study. Data from 89 patients with ASCVD or HF from January 2015 to February 2018 were analyzed regarding the effect of SGLT2 inhibitors and DPP4 inhibitors. Cardiovascular function was assessed by 2-D echocardiography and N-terminal prohormone of brain natriuretic peptide (NT-pro BNP).

Results

A total of 89 patients with T2DM were considered in two groups of SGLT2 inhibitors (n=41) and DPP4 inhibitors (n=48). The mean follow-up period was 2 years, with a total of 89 patient-years. Despite no significant change in systolic function, SGLT2 inhibitors improved cardiovascular function, as demonstrated by a reduced left ventricular ejection fraction less than 40%, ratio of mitral peak velocity of early filling velocity to early diastolic mitral annular velocity, ratio of early to late ventricular filling velocities, and NT-pro BNP compared with the DPP4 inhibitor group.

Conclusion

SGLT2 inhibitors improve cardiovascular function in T2DM with coronary artery disease compared to DPP4 inhibitors.

Cardiovascular outcome studies in type 2 diabetes: Comparison between SGLT2 inhibitors and GLP-1 receptor agonists

Sodium-glucose cotransporter type 2 inhibitors (SGLT2is) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) are two pharmacological classes that have proven their efficacy to reduce major cardiovascular events (MACEs) in patients with type 2 diabetes mellitus (T2DM) and established cardiovascular disease in large prospective cardiovascular outcome trials (CVOTs): EMPA-REG OUTCOME (empagliflozin), CANVAS (canagliflozin), LEADER (liraglutide) and SUSTAIN 6 (semaglutide). Some heterogeneity appears to exist between the various agents within the two pharmacological classes. Whether these positive results could be extrapolated to patients without cardiovascular disease is still unknown. The underlying mechanisms remain a matter of debate but appear to differ between SGLT2is and GLP-1RAs. One crucial question is which patient's characteristics should be taken into account to guide the choice between a SGLT2i or a GLP-1RA according to a personalized approach. Heart failure should encourage the use of a SGLT2i whereas moderate to severe chronic kidney disease should favour the prescription of a GLP-1RA. Despite the results of recent CVOTs, numerous patients who are good candidates for benefiting of these agents do not receive them in clinical practice. Currently, there is a paradigm shift in T2DM management, moving from a primary objective of glucose control to a cardiovascular and renal protection.

Nocturnal Hypoglycemia in Type 2 Diabetes

Background and aims: It is known that the majority of critical unacknowledged hypoglycemia has an increased incidence in patients with type 1 diabetes (T1DM) with a long evolution. The aim of this research is to evaluate the variability of glucose level and hypoglycemic events in patients with type 2 diabetes (T2DM) having pharmacological interventions with hypoglycemic risk. These events are sometimes asymptomatic also in T2DM: frequently in elderly, patients with autonomic neuropathy, or having a long evolution of disease.

Material and method: This analysis includes 72 patients with T2DM, with a relative good metabolic control, and possible glucose fluctuations. Glucose variability was appreciated using continuous glucose monitoring systems (CGMS) used for more than 72 hours in hospital or ambulatory setting.

Results: The incidence, duration and severity of hypoglycemia are not correlated with HbA1c value, age, disease duration or treatment. Approximately a quarter of patients had nocturnal hypoglycemia and in 37,5% of events hypoglycemia was prolonged, more 45 minutes. Clinical manifestations in diurnal hypoglycemia were presents in only 40% of the recorded events.

Conclusions: The study suggested that CGMS is beneficial for patients with type 2 diabetes, with hypoglycemic risk and complications, to adjusted medication, education and prevention the cardiovascular events.

Phlorizin Exerts Direct Protective Effects on Palmitic Acid (PA)-Induced Endothelial Dysfunction by Activating the PI3K/AKT/eNOS Signaling Pathway and Increasing the Levels of Nitric Oxide (NO)

Background

Sodium glucose transporter-2 inhibitors are the newest antidiabetic drugs that seem to be cardioprotective and can prevent type 2 diabetes in patients with high cardiovascular risks. Previous clinical trials have shown that these inhibitors can alleviate endothelial dysfunction, but the mechanism of action remains unknown. How SGLT inhibitor influences the release of NO in PA-induced HUVECs has never been reported.

Material/Methods

To explore the potential effects of the endothelial-protective mechanism of phlorizin and its impact on nitric oxide (NO), human umbilical vein endothelial cells (HUVECs) were incubated with palmitic acid (PA) and then treated with phlorizin. Western blotting was performed to assess the phosphorylation of AKT, eNOS, and IRS-1. To further explore potential targets, siRNA transfection was used to demonstrate the role of SGLT1 and SGLT2.

Results

Phlorizin suppressed the expression of SGLT1 and SGLT2, activated the PI3K/AKT/eNOS signaling pathway, increased the output of NO, and promoted the consumption of glucose in PA-induced HUVECs. Through demonstrating siRNA suppression of the expression of SGLT1 and SGLT2 in PA-induced HUVECs, this study provides a new understanding of the mechanism behind SGLT1 and SGLT2.

Conclusions

Our data demonstrate that phlorizin ameliorates the endothelial dysfunction link with the activation of the PI3K/AKT/eNOS signaling pathway and augmentation of the release of NO, partially through suppressing the expression of SGLT1 and SGLT2 in PA-induced HUVECS.

Cost-effectiveness of vildagliptin for people with type 2 diabetes mellitus in Brazil; findings and implications

INTRODUCTION

Vildagliptin is an inhibitor of the enzyme dipeptidyl peptidase 4, indicated for the treatment of type 2 diabetes mellitus, combined or not with metformin. This study aims to evaluate the cost-effectiveness of vildagliptin in the Brazilian context. Areas covered: Using MEDLINE, Cochrane Library, Lilacs and CRD, six studies were selected for the economic models. This study utilised cost data in the Brazilian health system to provide the context. Expert commentary: Type 2 diabetes mellitus is an epidemic disease and represents a challenge for all health care systems. Although guidelines clearly define first-line treatment, there are several other promising treatments. Vildagliptin is one of them, resulting in a mean lifetime increase of 0.31 years compared to metformin alone and 1.19 more life years compared to other metformin combinations. Considering observational data, life years with dual vildagliptin-containing treatments were 0.37 more compared to other dual treatments. However, its high cost versus generic metformin and its unclear safety profile weakens its subsequent cost-effectiveness. Consequently, the incorporation of vildagliptin or its combination with metformin is currently not recommended for the Brazilian Health Care System. This may change as more data becomes available.

The Landscape of Glucose-Lowering Therapy and Cardiovascular Outcomes: From Barren Land to Metropolis

The choice of glucose-lowering therapy (GLT) has expanded to include 11 different classes in addition to insulin. Since the 2008 Food and Drug Administration guidance for industry and mandate of demonstrating cardiovascular (CV) safety prior to any new drug approval, there were several trials primarily conducted to establish that goal. Some had neutral effects, while there were positively beneficial outcomes with more recent studies. Hospitalization for congestive heart failure has also been a heterogeneous finding among the different classes of GLT, with drug outcomes ranging from risky to beneficial. The current review selectively focuses on the evidence for CV outcomes for each class of GLT and summarizes the existing guidelines with regard to these drugs in heart disease. Moreover, it illustrates the dynamic status in the development of evidence. Finally, the review enables healthcare providers to formulate a plan for hypoglycemic therapy which will optimize CV health, in a patient-centered manner.