Impact of acute hyperglycemia on myocardial infarct size, area at risk, and salvage in patients with STEMI and the association with exenatide treatment: results from a randomized study

Disulfide stress and its role in cardiovascular diseases

Cardiovascular disease (CVD) is one of the leading causes of mortality in humans, and oxidative stress plays a pivotal role in disease progression. This phenomenon typically arises from weakening of the cellular antioxidant system or excessive accumulation of peroxides. This review focuses on a specialized form of oxidative stress-disulfide stress-which is triggered by an imbalance in the glutaredoxin and thioredoxin antioxidant systems within the cell, leading to the accumulation of disulfide bonds. The genesis of disulfide stress is usually induced by extrinsic pathological factors that disrupt the thiol-dependent antioxidant system, manifesting as sustained glutathionylation of proteins, formation of abnormal intermolecular disulfide bonds between cysteine-rich proteins, or irreversible oxidation of thiol groups to sulfenic and sulfonic acids. Disulfide stress not only precipitates the collapse of the antioxidant system and the accumulation of reactive oxygen species, exacerbating oxidative stress, but may also initiate cellular inflammation, autophagy, and apoptosis through a cascade of signaling pathways. Furthermore, this review explores the detrimental effects of disulfide stress on the progression of various CVDs including atherosclerosis, hypertension, myocardial ischemia-reperfusion injury, diabetic cardiomyopathy, cardiac hypertrophy, and heart failure. This review also proposes several potential therapeutic avenues to improve the future treatment of CVDs.

Clinical, electrocardiographic, echocardiographic, and angiographic predictors for the final infarct size assessed by cardiac magnetic resonance in acute STEMI patients after primary percutaneous coronary intervention

BACKGROUND

Final infarct size (IS) after ST segment elevation myocardial infarction (STEMI) is a major predictor of mortality. Seeking early predictors for final IS can guide individualized therapeutic strategies for those recognized to be at higher risk.

RESULTS

Eighty STEMI patients successfully treated with primary percutaneous coronary intervention (pPCI) underwent baseline (within 48 h) 2D, 3D echocardiography with speckle tracking and then underwent cardiac magnetic resonance (CMR) at 3 months to assess the final IS. After recruitment, 4 patients were excluded for uncontainable claustrophobia while 76 patients completed the final analysis. The mean ± standard deviation age was 54.1 ± 10.9 years, 84% were males, 25% had diabetes, 26% were hypertensives, 71% were current smokers, 82% had dyslipidemia, and 18% had a family history of premature coronary artery disease. By 3 months, CMR was performed to accurately evaluate the final IS. In univariate regression analysis, the admission heart rate, baseline and post-pPCI ST elevation, STEMI location (anterior vs. inferior), highest peri-procedural troponin, large thrombus burden, baseline thrombolysis in myocardial infarction flow grade, the final myocardial blush grade, the 2D and 3D left ventricular ejection fraction (LVEF), and the 2D and 3D global longitudinal strain (GLS) parameters were significant predictors for the final IS. In the multivariate regression analysis, four models were constructed and recognized the residual post-PCI ST segment elevation, the highest peri-procedural troponin, the 2D-LVEF, 3D-LVEF, and 2D-GLS as significant independent predictors for final IS.

CONCLUSIONS

In STEMI patients who underwent successful pPCI, early predictors for the final IS are vital to guide therapeutic decisions. The residual post-pPCI ST elevation, the highest peri-procedural troponin, and the baseline 2D-LVEF, 3D-LVEF, and 2D-GLS can be excellent and timely tools to predict the final IS.

The cardiovascular effects of GLP-1 receptor agonists beyond obesity and type 2 diabetes: An anti-atherosclerotic action

Obesity and overweight affect almost one third of the European population. Obesity and its associated conditions, including type 2 diabetes, significantly impact healthcare systems, life expectancy and quality of life. The emergence of glucagon-like peptide-1 (GLP-1) receptor agonists for the treatment of obesity, with or without diabetes, has provided an effective alternative to metabolic surgery and dietary interventions. We are now beginning to understand their pleiotropic effects beyond weight loss, such as their favourable impact on cardiovascular profiles. The aim of this review is to summarize available preclinical and clinical data on the beneficial effects of GLP-1 receptor agonists on atherosclerosis and cardiovascular disease which has the potential to substantially broaden the scope of their clinical applications.

Stress hyperglycemia and poor outcomes in patients with ST-elevation myocardial infarction: a systematic review and meta-analysis

Background

Hyperglycemia, characterized by elevated blood glucose levels, is frequently observed in patients with acute coronary syndrome, including ST-elevation myocardial infarction (STEMI). There are conflicting sources regarding the relationship between hyperglycemia and outcomes in STEMI patients. We aimed to compile evidence to assess the association between hyperglycemia and adverse outcomes.

Methods

We conducted a comprehensive search for articles on PubMed and Embase using search strategies which yielded 4,061 articles. After full-text screening, 66 articles were included for systematic review, and 62 articles were further selected for meta-analysis.

Results

The 66 included articles spanned the years 2005-2023. Of these, 45 articles reported admission blood glucose, 13 articles used HbA1c, and 7 articles studied fasting blood glucose. Most studies defined STEMI with primary PCI as their inclusion criteria. Mortality was the most often outcome reported related to hyperglycemia. Overall, 55 (83.3%) studies were at low risk of bias. Both admission and fasting blood glucose were significantly related to short- and long-term mortality after STEMI, with a pooled risk ratio (RR) of 3.02 (95%CI: 2.65-3.45) and 4.47 (95% CI: 2.54-7.87), respectively. HbA1c showed substantial association with long-term mortality (HR 1.69, 95% CI: 1.31-2.18)) with a pooled RR of 1.58 (95% CI 1.26-1.97). In subsequent analyses, admission hyperglycemia was associated with an increased risk of reinfarction (pooled RR 1.69, 95% CI 1.31-2.17), heart failure (pooled RR 1.56, 95% CI: 1.37-1.77), cardiogenic shock (pooled RR 3.68, 95% CI 2.65-5.11), repeat PCI or stent thrombosis (pooled RR 1.99, 95% CI 1.21-3.28), and composite major adverse cardiac and cerebrovascular events (MACCE) (pooled RR 1.99, 95% CI: 1.54-2.58).

Conclusions

Our study demonstrated that hyperglycemia has a strong association with poor outcomes after STEMI. Admission and fasting blood glucose are predictors for short-term outcomes, while HbA1c is more appropriate for predicting longer-term outcomes in STEMI patients.

Systematic Review Registration

PROSPERO 2021 (CRD42021292985).

Glucagon-like peptide 1 receptor agonists: cardiovascular benefits and mechanisms of action

Type 2 diabetes mellitus (T2DM) and obesity are metabolic disorders characterized by excess cardiovascular risk. Glucagon-like peptide 1 (GLP1) receptor (GLP1R) agonists reduce body weight, glycaemia, blood pressure, postprandial lipaemia and inflammation - actions that could contribute to the reduction of cardiovascular events. Cardiovascular outcome trials (CVOTs) have demonstrated that GLP1R agonists reduce the rates of major adverse cardiovascular events in patients with T2DM. Separate phase III CVOTs of GLP1R agonists are currently being conducted in people living with heart failure with preserved ejection fraction and in those with obesity. Mechanistically, GLP1R is expressed at low levels in the heart and vasculature, raising the possibility that GLP1 might have both direct and indirect actions on the cardiovascular system. In this Review, we summarize the data from CVOTs of GLP1R agonists in patients with T2DM and describe the actions of GLP1R agonists on the heart and blood vessels. We also assess the potential mechanisms that contribute to the reduction in major adverse cardiovascular events in individuals treated with GLP1R agonists and highlight the emerging cardiovascular biology of novel GLP1-based multi-agonists currently in development. Understanding how GLP1R signalling protects the heart and blood vessels will optimize the therapeutic use and development of next-generation GLP1-based therapies with improved cardiovascular safety.

Salidroside facilitates therapeutic angiogenesis in diabetic hindlimb ischemia by inhibiting ferroptosis

Hindlimb ischemia (HLI), in which blood perfusion to the hindlimb is obstructed, is one of the major complications of diabetes. Skeletal muscle cells are crucial for revascularization as they can secrete various angiogenic factors; however, hyperglycemia impairs their viability and subsequently their angiogenic potential. Salidroside can promote skeletal muscle cell viability under hyperglycemia; however, the molecular mechanism is still poorly understood. Here we revealed that salidroside could suppress hyperglycemia-induced ferroptosis in skeletal muscle cells by promoting GPX4 expression, thereby restoring their viability and paracrine functions. These in turn promoted the proliferation and migration potentials of blood vessel-forming cells. Furthermore, we showed that salidroside/GPX4-mediated ferroptosis inhibition is crucial for promoting angiogenesis and blood perfusion recovery in diabetic HLI mice. Together, we reveal a novel molecular mechanism of salidroside in enhancing skeletal muscle cells-mediated revascularization and blood perfusion recovery in diabetic HLI mice, further highlighting it as a potential compound for treating diabetic HLI.

Admission hyperglycemia in acute myocardial infarction is associated with an increased risk of arrhythmias: A systematic review and meta-analysis

Background

Admission hyperglycemia (AH) has shown to be associated with higher mortality rates in acute myocardial infarction (AMI). Malignant arrhythmia is one of the causes of death in AMI; however, it is unclear whether AH is associated with an increased arrhythmia risk. We conducted this systematic review and meta-analysis to assess the association between AH and arrhythmias in AMI.

Methods

We searched MEDLINE, and Embase databases from inception to September 2021 to identify studies that compared arrhythmia rates between AMI patients with AH and those without. Arrhythmias of interest included ventricular tachyarrhythmias (VA), atrial fibrillation (AF), and atrioventricular block.

Results

Thirteen cohort studies with a total of 12,898 patients were included. AH was associated with a higher risk of overall arrhythmias (18% vs 10.3%, pooled odds ratio [OR] = 1.89, 95% confidence interval [CI]: 1.39-2.56, P < .001), VA (16.4% vs 11.1%, pooled OR = 1.56, 95% CI: 1.11-2.18, P = .01), and new onset AF (17.8% vs 6.4%, pooled OR = 2.13, 95% CI: 1.4-3.25, P < .0010. Subgroup analysis of diabetes status regarding overall arrhythmias showed that the increased risk of arrhythmias in the AH group was consistent in both patients with a history of diabetes (18% vs 12.5%, pooled OR = 2.33, 95%CI: 1.2-4.52, P = .004) and without (15.7%. vs 9% pooled OR = 1.35, 95% CI: 1.1-1.66, P = .013).

Conclusion

Admission hyperglycemia in AMI was associated with the increased risk of arrhythmias, regardless of history of diabetes mellitus.

Glycemic gap and the outcome of diabetic patients presenting with acute coronary syndrome

Background

Acute hyperglycemia is a common finding in both diabetic and non-diabetic patients with acute coronary syndrome (ACS) who present to the emergency department (ED). The prognostic role of hyperglycemia in diabetic patients with ACS remains controversial at least on the short-term basis. The aim of the present study was to find the relation between the glycemic gap and clinical outcome in diabetic patients with ACS.

Methods

The study included 100 diabetic patients with ACS to who were prospectively followed during their hospital stay. Admission blood glucose was measured and glycemic gap was calculated.

Results

In diabetic patients suffering ACS, there was a significant relation between the glycemic gap value, occurrence of major adverse cardiovascular events (MACE) and length of hospital stay.

Conclusion

Glycemic gap is a better marker than admission blood glucose alone in diabetic patients presenting with ACS. This study added the optimal cut-off value for this important biomarker.

Update on Cardioprotective Strategies for STEMI: Focus on Supersaturated Oxygen Delivery

Despite the fact that door-to-balloon times have been greatly reduced, the rates of death and the incidence of heart failure in patients with ST-segment elevation myocardial infarction (MI) have plateaued. There is still an unmet need to further reduce MI size in the reperfusion era. Most adjunctive therapies to enhance myocardial salvage have failed, but some have shown promise. Currently, the only adjunctive therapy in a pivotal trial that has demonstrated reductions in infarct size is localized delivery of supersaturated oxygen (SSO₂) therapy. This review provides background on prior infarct size reduction efforts. The authors describe the preclinical data that shows the effectiveness of SSO₂ in reducing MI size, improving regional myocardial blood flow and cardiac function, and reducing adverse left ventricular remodeling-presumably by reducing patchy areas of residual ischemia within the reperfused risk zone. Potential mechanisms by which SSO₂ is beneficial are described, including the delivery of high levels of dissolved oxygen through plasma to ischemic, but viable, vascular and myocardial cells, thus allowing their survival and function. The authors then describe the SSO₂ clinical trials, demonstrating that in patients with anterior ST-segment elevation MI, SSO₂ therapy safely and effectively reduces infarct size, improves cardiac function, and reduces adverse left ventricular remodeling.

Optimal glucose, HbA1c, glucose-HbA1c ratio and stress-hyperglycaemia ratio cut-off values for predicting 1-year mortality in diabetic and non-diabetic acute myocardial infarction patients

Background

Stress-induced hyperglycaemia at time of hospital admission has been linked to worse prognosis following acute myocardial infarction (AMI). In addition to glucose, other glucose-related indices, such as HbA1c, glucose-HbA1c ratio (GHR), and stress-hyperglycaemia ratio (SHR) are potential predictors of clinical outcomes following AMI. However, the optimal blood glucose, HbA1c, GHR, and SHR cut-off values for predicting adverse outcomes post-AMI are unknown. As such, we determined the optimal blood glucose, HbA1c, GHR, and SHR cut-off values for predicting 1-year all cause mortality in diabetic and non-diabetic ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) patients.

Methods

We undertook a national, registry-based study of patients with AMI from January 2008 to December 2015. We determined the optimal blood glucose, HbA1c, GHR, and SHR cut-off values using the Youden’s formula for 1-year all-cause mortality. We subsequently analyzed the sensitivity, specificity, positive and negative predictive values of the cut-off values in the diabetic and non-diabetic subgroups, stratified by the type of AMI.

Results

There were 5841 STEMI and 4105 NSTEMI in the study. In STEMI patients, glucose, GHR, and SHR were independent predictors of 1-year all-cause mortality [glucose: OR 2.19 (95% CI 1.74–2.76); GHR: OR 2.28 (95% CI 1.80–2.89); SHR: OR 2.20 (95% CI 1.73–2.79)]. However, in NSTEMI patients, glucose and HbA1c were independently associated with 1-year all-cause mortality [glucose: OR 1.38 (95% CI 1.01–1.90); HbA1c: OR 2.11 (95% CI 1.15–3.88)]. In diabetic STEMI patients, SHR performed the best in terms of area-under-the-curve (AUC) analysis (glucose: AUC 63.3%, 95% CI 59.5–67.2; GHR 68.8% 95% CI 64.8–72.8; SHR: AUC 69.3%, 95% CI 65.4–73.2). However, in non-diabetic STEMI patients, glucose, GHR, and SHR performed equally well (glucose: AUC 72.0%, 95% CI 67.7–76.3; GHR 71.9% 95% CI 67.7–76.2; SHR: AUC 71.7%, 95% CI 67.4–76.0). In NSTEMI patients, glucose performed better than HbA1c for both diabetic and non-diabetic patients in AUC analysis (For diabetic, glucose: AUC 52.8%, 95% CI 48.1–57.6; HbA1c: AUC 42.5%, 95% CI 37.6–47. For non-diabetic, glucose: AUC 62.0%, 95% CI 54.1–70.0; HbA1c: AUC 51.1%, 95% CI 43.3–58.9). The optimal cut-off values for glucose, GHR, and SHR in STEMI patients were 15.0 mmol/L, 2.11, and 1.68 for diabetic and 10.6 mmol/L, 1.72, and 1.51 for non-diabetic patients respectively. For NSTEMI patients, the optimal glucose values were 10.7 mmol/L for diabetic and 8.1 mmol/L for non-diabetic patients.

Conclusions

SHR was the most consistent independent predictor of 1-year all-cause mortality in both diabetic and non-diabetic STEMI, whereas glucose was the best predictor in NSTEMI patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01395-3.

Reducing Cardiac Injury during ST-Elevation Myocardial Infarction: A Reasoned Approach to a Multitarget Therapeutic Strategy

The significant reduction in ‘ischemic time’ through capillary diffusion of primary percutaneous intervention (pPCI) has rendered myocardial-ischemia reperfusion injury (MIRI) prevention a major issue in order to improve the prognosis of ST elevation myocardial infarction (STEMI) patients. In fact, while the ischemic damage increases with the severity and the duration of blood flow reduction, reperfusion injury reaches its maximum with a moderate amount of ischemic injury. MIRI leads to the development of post-STEMI left ventricular remodeling (post-STEMI LVR), thereby increasing the risk of arrhythmias and heart failure. Single pharmacological and mechanical interventions have shown some benefits, but have not satisfactorily reduced mortality. Therefore, a multitarget therapeutic strategy is needed, but no univocal indications have come from the clinical trials performed so far. On the basis of the results of the consistent clinical studies analyzed in this review, we try to design a randomized clinical trial aimed at evaluating the effects of a reasoned multitarget therapeutic strategy on the prevention of post-STEMI LVR. In fact, we believe that the correct timing of pharmacological and mechanical intervention application, according to their specific ability to interfere with survival pathways, may significantly reduce the incidence of post-STEMI LVR and thus improve patient prognosis.

Hyperglycemia, inflammatory response and infarct size in obstructive acute myocardial infarction and MINOCA

BACKGROUND

Hyperglycemia has been associated with increased inflammatory indexes and larger infarct sizes in patients with obstructive acute myocardial infarction (obs-AMI). In contrast, no studies have explored these correlations in non-obstructive acute myocardial infarction (MINOCA). We investigated the relationship between hyperglycemia, inflammation and infarct size in a cohort of AMI patients that included MINOCA.

METHODS

Patients with AMI undergoing coronary angiography between 2016 and 2020 were enrolled. The following inflammatory markers were evaluated: C-reactive protein, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and neutrophil-to-platelet ratio (NPR). Myocardial infarct size was measured by peak high sensitivity troponin I (Hs-TnI) levels, left-ventricular-end-diastolic-volume (LVEDV) and left ventricular ejection fraction (LVEF).

RESULTS

The final study population consisted of 2450 patients with obs-AMI and 239 with MINOCA. Hyperglycemia was more prevalent among obs-AMI cases. In all hyperglycemic patients-obs-AMI and MINOCA-NLR, NPR, and LPR were markedly altered. Hyperglycemic obs-AMI subjects exhibited a higher Hs-TnI (p < 0.001), a larger LVEDV (p = 0.003) and a lower LVEF (p < 0.001) compared to normoglycemic ones. Conversely, MINOCA patients showed a trivial myocardial damage, irrespective of admission glucose levels.

CONCLUSIONS

Our data confirm the association of hyperglycemic obs-AMI with elevated inflammatory markers and larger infarct sizes. MINOCA patients exhibited modest myocardial damage, regardless of admission glucose levels.

Unique role of admission hyperglycemia on myocardial infarction size and area at risk following an acute ST-elevation myocardial infarction

Background

Hyperglycemia can adversely affect patients with acute ST-elevation myocardial infarction (STEMI) in both diabetic and non-diabetic patients. The majority of the studies had investigated the impact of admission hyperglycemia (AH) on cardiovascular morbidity and mortality while, in ours, we entailed its impact on final infarction size (FIS) and more interestingly, on the area at risk (AAR), both were estimated by cardiac magnetic resonance (CMR) imaging.

Results

AH showed significant positive correlations to FIS and AAR. Moreover, AH group had higher summation of ST segment elevation (sum STE), more maximum ST segment elevation (max STE), higher echocardiographic wall motion score index (WMSI), higher CMR estimated WMSI, and lower segmental ejection fraction (EF). Multivariate analysis showed that AH was independently associated with increased FIS.

Conclusion

Current study showed an association between AH and large FIS in STEMI patients.

Association of coronary artery dominance and mortality rate and complications in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention

Background

Percutaneous coronary intervention (PCI) is the treatment of choice for patients with ST-segment elevation myocardial infarction (STEMI). Effect of coronary artery dominance on the patients' outcome following primary PCI (PPCI) is not fully investigated. We investigated the association of coronary artery dominance with complications and 1-year mortality rate of PPCI.

Materials and Methods

In this retrospective study, patients with STEMI treated with PPCI from March 2016 to February 2018 were divided into three groups based on their coronary dominancy: left dominance (LD), right dominance (RD), and codominant. Demographic characteristics, medical history, results of physical examination, electrocardiography, angiography, and echocardiography were compared between the groups.

Results

Of 491 patients included in this study, 34 patients (7%) were LD and 22 patients (4.5%) were codominant. Accordingly, 54 propensity-matched RD patients were included in the analysis. The demographics and comorbidities of the three groups were not different (P > 0.05); however, all patients in the RD group had thrombolysis in myocardial infarction (TIMI) 3, while five patients in the LD and five patients in the codominant group had a TIMI ≤2 (P = 0.006). At admission, the median left ventricular ejection fraction (LVEF) was highest in RD patients and lowest in LD and codominant patients (34%, P = 0.009). There was no difference in terms of success or complications of PCI, in-hospital, and 1-year mortality rate (P > 0.05).

Conclusion

Patients with left coronary artery dominance had a higher value of indicators of worse outcomes, such as lower LVEF and TIMI ≤ 2, compared with RD patients, but not different rates of success or complications of PCI, in-hospital, and 1-year mortality. This finding may suggest that interventionists should prepare themselves with protective measures for no-reflow and slow-flow phenomenon and also mechanical circulatory support before performing PPCI in LD patients.

Cardiovascular outcomes trials with incretin-based medications: a critical review of data available on GLP-1 receptor agonists and DPP-4 inhibitors

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors are so called "incretin-based therapies" (IBTs) that represent innovative therapeutic approaches and are commonly used in clinical practice for the treatment of type 2 diabetes mellitus (T2DM). The cardiovascular outcome trials (CVOTs) have provided useful information that has helped to shape changes in clinical practice guidelines for the management of T2DM. At the same time, the mechanisms that may explain the nonglycemic and cardiovascular (CV) benefits of these medications are still being explored. A summary of the main findings from CVOTs performed to-date with particular emphasis on various outcomes and inconsistencies observed in the trials is provided. Overall, available data is favourable to the early deployment of GLP-1RAs in clinical practice, fully in line with recommendations from international scientific guidelines, and based on their effects on glucose metabolism parameters, body weight reduction and CV outcomes. Evidence further suggest that the CV benefits of GLP-1RAs may not be a class effect, with GLP-1 analogues having a greater benefit rather than exendin-based agents.

Impact of stress hyperglycemia on myocardial salvage in patients with ST-Elevation myocardial infarction: Cardiac magnetic resonance study

Cardiovascular complications in ST-segment–elevation myocardial infarction survivors remain substantial despite advances in the management of STEMI. We aimed to determine effect of AH on the area at risk (AAR), final infarct size (FIS), and salvage index (SI) in STEMI patients using cardiac magnetic resonance (CMR). 43 successfully reperfused STEMI patients were recruited. CMR was utilized to estimate AAR and FIS, SI was calculated: SI = AAR- FIS/AAR. AH showed significant positive correlations to FIS (r-value = 0.538, P = < 0.001), and AAR (r-value = 0.435, P = 0.002), and a negative correlation with SI (r-value = −0.378, P = 0.006).

Prognostic value of fasting glucose on the risk of heart failure and left ventricular systolic dysfunction in non-diabetic patients with ST-segment elevation myocardial infarction

Recent studies have shown that acute blood glucose elevation in patients with ST-segment elevation myocardial infarction (STEMI) suggests a poor prognosis. To investigate the effect of fasting blood glucose (FBG) on the risk of heart failure (HF) and left ventricular systolic dysfunction (LVSD) in non-diabetic patients undergoing primary percutaneous coronary intervention (PCI) for acute STEMI, we retrospectively recruited consecutive non-diabetic patients who underwent primary PCI for STEMI in our hospital from February 2003 to March 2015. The patients were divided into two groups according to the FBG level. A total of 623 patients were recruited with an age of 61.3 ± 12.9 years, of whom 514 (82.5%) were male. The HF risk (odds ratio 3.401, 95% confidence interval (CI) 2.144-5.395, P < 0.001) was significantly increased in patients with elevated FBG than those with normal FBG. Elevated FBG was also independently related to LVSD (β 1.513, 95%CI 1.282-1.785, P < 0.001) in a multiple logistics regression analysis. In conclusion, elevated FBG was independently associated with 30-day HF and LVSD risk in non-diabetic patients undergoing primary PCI for STEMI.

Diabetes Mellitus and Acute Myocardial Infarction: Impact on Short and Long-Term Mortality

Diabetes mellitus (DM) is an important risk factor for acute myocardial infarction (AMI) and a frequent co-morbidity in patients hospitalized with AMI, being present in about 30% of cases. Although current treatment of AMI has considerably improved survival in both patients with and without DM, the presence of DM still doubles the case fatality rate during both the acute phase of AMI and at long-term follow-up. This higher mortality risk of DM patients strongly indicates a particular need for better treatment options in these patients and suggests that intensive medical treatment, prolonged surveillance, and stringent control of other risk factors should be carefully pursued and maintained for as long as possible in them.In this review, we will focus on the close association between DM and in-hospital and long-term mortality in AMI patients. We will also aim at providing current evidence on the mechanisms underlying this association and on emerging therapeutic strategies, which may reduce the traditional mortality gap that still differentiates AMI patients with DM from those without.

The use of GLP-1 receptor agonists in hospitalised patients: An untapped potential

In the outpatient setting, glucagon-like peptide-1 (GLP-1) receptor agonists have proved to be highly efficacious drugs that provide glycaemic control with a low risk of hypoglycaemia. These characteristics make GLP-1 receptor agonists attractive agents to treat dysglycaemia in perioperative or high-dependency hospital settings, where glycaemic variability and hyperglycaemia are associated with poor prognosis. GLP-1 also has a direct action on the myocardium and vasculature-which may be advantageous in the immediate aftermath of a vascular insult. This is a narrative review of the work in this area. The aim was to determine the populations of hospitalised patients being evaluated and the clinical and mechanistic end-points tested, with the institution of GLP-1 therapy in hospital. We searched the PubMed, Embase, and Google scholar databases, combining the term "glucagon-like peptide 1" OR "GLP-1" OR "incretin" OR "liraglutide" OR "exenatide" OR "lixisenatide" OR "dulaglutide" OR "albiglutide" AND "inpatient" OR "hospital" OR "perioperative" OR "postoperative" OR "surgery" OR "myocardial infarction" OR "stroke" OR "cerebrovascular disease" OR "transient ischaemic attack" OR "ICU" OR "critical care" OR "critical illness" OR "CCU" OR "coronary care unit." Pilot studies were reported in the fields of acute stroke, cardiac resuscitation, coronary care, and perioperative care that showed advantages for GLP-1 therapy, with normalisation of glucose, lower glucose variability, and lower risk of hypoglycaemia. Animal and human studies have reported improvements in myocardial performance when given acutely after vascular insult or surgery, but these have yet to be translated into randomised clinical trials.

Glucose-lowering therapy and cardiovascular outcomes in patients with type 2 diabetes mellitus and acute coronary syndrome

Diabetes is a common comorbidity in patients hospitalized for an acute coronary syndrome event, and prevalence is increasing. Among patients hospitalized with acute myocardial infarction, diabetes can be an independent predictor of mortality and new cardiovascular events; both short- and long-term outcomes are worse for patients with diabetes relative to those without, and undiagnosed diabetes is associated with greater mortality. The impact of glycemic control on cardiovascular outcomes and the best approach to treat hyperglycemia upon hospital admission for acute coronary syndrome in patients with or without known diabetes remain open questions. This review assesses available evidence for hyperglycemia management at the time of admission for acute coronary syndrome and, thereafter, finds that (1) admission plasma glucose plays a role in predicting adverse events, especially in patients with unknown diabetes; (2) glycated haemoglobin is a likely predictor of events in patients with unknown diabetes; and (3) hypoglycemia at the time of acute myocardial infarction hospital admission is an important predictor for mortality in patients with and without diabetes. Whether glucose-targeted insulin and glucose infusion have advantages over glucose-insulin-potassium infusion remains controversial. Evidence for the effect of novel glucose-lowering agents used at the time of an acute cardiovascular event is limited and requires more dedicated studies.

Tyrosol Facilitates Neovascularization by Enhancing Skeletal Muscle Cells Viability and Paracrine Function in Diabetic Hindlimb Ischemia Mice

As one of the most severe manifestations of diabetes, vascular complications are the main causes of diabetes-related morbidity and mortality. Hyperglycemia induces systemic abnormalities, including impaired angiogenesis, causing diabetic patients to be highly susceptible in suffering hindlimb ischemia (HLI). Despite its severe prognosis, there is currently no effective treatment for diabetic HLI. Skeletal muscle cells secrete multiple angiogenic factors, hence, recently are reported to be critical for angiogenesis; however, hyperglycemia disrupted the paracrine function in skeletal muscle cells, leading to the impaired angiogenesis potential observed in diabetic patients. The present study showed that tyrosol, a phenylethanoid compound, suppresses accumulation of intracellular reactive oxygen species (ROS) caused by hyperglycemia, most plausibly by promoting heme oxygenase-1 (HO-1) expression in skeletal muscle cells. Consequently, tyrosol exerts cytoprotective function against hyperglycemia-induced oxidative stress in skeletal muscle cells, increases their proliferation vigorously, and simultaneously suppresses apoptosis. Furthermore, tyrosol grossly increases the secretion of vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor-BB (PDGF-BB) from skeletal muscle cells. This leads to enhanced proliferation and migration capabilities of vascular endothelial and smooth muscle cells, two types of cells that are responsible in forming blood vessels, through cell-cell communication. Finally, in vivo experiment using the diabetic HLI mouse model showed that tyrosol injection into the gastrocnemius muscle of the ischemic hindlimb significantly enhances the formation of functional blood vessels and subsequently leads to significant recovery of blood perfusion. Overall, our findings highlight the potential of the pharmacological application of tyrosol as a small molecule drug for therapeutic angiogenesis in diabetic HLI patients.

High admission glucose levels predict worse short-term clinical outcome in non-diabetic patients with acute myocardial infraction: a retrospective observational study

BACKGROUND

Patients with acute myocardial infarction (AMI) often accompanied by admission hyperglycemia, which usually predicts a poor clinical outcomes for non-diabetes mellitus. Appropriate cut-point to identify high risk individuals in these patients remains controversial.

METHODS

One thousand six hundred ninety-eight non-diabetes AMI patients in this retrospective study were divided into 3 groups according to admission glucose levels (euglycemia group≤140 mg/dL, moderate hyperglycemia group 141-179 mg/dL, severe hyperglycemia group≥180 mg/dL). The primary endpoint of this study was all-cause in-hospital mortality rate. In-hospital motality related risk factors was analyzed by multivariate binary logistic regression analyses.

RESULTS

All myocardial necrosis markers and Log NT-proBNP in severe hyperglycemia group were significantly higher than those in the other 2 groups. Logistic regression showed that independent predictors of the in-hospital mortality rate in non-diabetic patients with AMI were age (OR = 1.057, 95% CI 1.024-1.091, P < 0.001), logarithm of the N-terminal pro-brain natriuretic peptide (OR = 7.697, 95% CI 3.810-15.550, P < 0.001), insufficient myocardial reperfusion (OR = 7.654, 95% CI 2.109-27.779, P < 0.001), percutaneous coronary intervention (OR = 0.221, 95% CI 0.108-0.452, P < 0.001) and admission glucose (as categorical variable). Patients with moderate hyperglycemia (OR = 1.186, 95% CI 0.585-2.408, P = .636) and severe hyperglycemia (OR = 4.595, 95% CI 1.942-10.873, P = 0.001) had a higher all-cause in-hospital mortality rate compared with those with euglycemia after AMI in non-diabetic patients.

CONCLUSIONS

The all-cause in-hospital mortality risk increases remarkably as admission glucose levels elevated in non-diabetic patients with AMI, especially in patients with admission glucose levels ≥180 mg/dL. Severe admission hyperglycemia could be regarded as prospective high-risk marker for non-diabetic AMI patients.

Advances in reducing cardiovascular risk in the management of patients with type 2 diabetes mellitus

Treatment intended to lower cardiovascular (CV) risk in patients with diabetes has always been a primary goal of diabetes treatment. Due to the subdued effects of reducing hemoglobin A1c (HbA1c) on macrovascular complications, controlling other CV risk factors such as hypertension and hyperlipidemia instead of hyperglycemia has been the mainstay treatment to improve CV outcome in patients with type 2 diabetes mellitus (T2DM) until recent years. This review is intended to summarize and compare the results from the available cardiovascular outcome trials (CVOTs) for the two classes of glucose lowering drug: sodium-glucose co-transporter 2 inhibitor (SGLT2i) and glucagon-like peptide-1 receptor agonist (GLP-1 RA). The results including the EMPA-REG, CANVAS program and DECLARE-TIMI 58 trials for SGLT2i, and the ELIXA, LEADER, SUSTAIN-6, EXSCEL and HARMONY trials for GLP-1 RA were summarized. The potential mechanisms of these CV beneficial effects and the optimal CV risk reduction treatment in patients with T2DM based on patient risk stratification and evidence from these CVOTs in real-world setting were discussed.

Impact of intravenous exenatide infusion for perioperative blood glucose control on myocardial ischemia-reperfusion injuries after coronary artery bypass graft surgery: sub study of the phase II/III ExSTRESS randomized trial

BACKGROUND

The aim of the study was to investigate whether intravenous (iv) infusion of exenatide, a synthetic GLP-1 receptor agonist, could provide a protective effect against myocardial ischemia-reperfusion injury after coronary artery bypass graft (CABG) surgery.

METHODS

A sub study analysis of patients > 18 years admitted for elective CABG and included in the ExSTRESS trial was conducted. Patients were randomized to receive either iv exenatide (1-h bolus of 0.05 µg min^-1 followed by a constant infusion of 0.025 µg min^-1) (exenatide group) or iv insulin therapy (control group) for blood glucose control (target range 100-139 mg dl^-1) during the first 48 h after surgical incision. All serum levels of troponin I measured during routine care in the Cardiac Surgery ICU were recorded. The primary outcome was the highest value of plasma concentration of troponin I measured between 12 and 24 h after ICU admission. The proportion of patients presenting an echocardiographic left ventricular ejection fraction (LVEF) > 50% at the follow-up consultation was compared between the two groups.

RESULTS

Finally, 43 and 49 patients were analyzed in the control and exenatide groups, respectively {age: 69 [61-76] versus 71 [63-75] years; baseline LVEF < 50%: 6 (14%) versus 16 (32%) patients; on-pump surgery: 29 (67%) versus 33 (67%) patients}. The primary outcome did not significantly differ between the two groups (3.34 [1.06-6.19] µg l^-1 versus 2.64 [1.29-3.85] µg l^-1 in the control and exenatide groups, respectively; mean difference (MD) [95% confidence interval (95% CI)] 0.16 [- 0.25; 0.57], p = 0.54). The highest troponin value measured during the first 72 h in the ICU was 6.34 [1.36-10.90] versus 5.04 [2.39-7.18] µg l^-1, in the control and exenatide groups respectively (MD [95% CI] 0.20 [- 0.22; 0.61], p = 0.39). At the follow-up consultation, 5 (12%) versus 8 (16%) patients presented a LVEF < 50% in the control and in the exenatide groups respectively (relative risk [95% CI] 0.68 [0.16; 2.59], p = 0.56).

CONCLUSIONS

Postoperative iv exenatide did not provide any additional cardioprotective effect compared to iv insulin in low-risk patients undergoing scheduled CABG surgery. Trial registration ClinicalTrials.gov Identifier NCT01969149, date of registration: January 7th, 2015; EudraCT No. 2009-009254-25 A, date of registration: January 6th, 2009.

Hyperglycemia and risk of ventricular tachycardia among patients hospitalized with acute myocardial infarction

Background

Little is known about the association of hyperglycemia with the development of ventricular tachycardia (VT) in patients hospitalized with acute myocardial infarction (AMI) which we examined in the present study. The objectives of this community-wide observational study were to examine the relation between elevated serum glucose levels at the time of hospital admission for AMI and occurrence of VT, and time of occurrence of VT, during the patient’s acute hospitalization.

Methods

We used data from a population-based study of patients hospitalized with AMI at all central Massachusetts medical centers between 2001 and 2011. Hyperglycemia was defined as a serum glucose level ≥ 140 mg/dl at the time of hospital admission. The development of VT was identified from physicians notes and electrocardiographic findings by our trained team of data abstractors.

Results

The average age of the study population was 70 years, 58.0% were men, and 92.7% were non-Hispanic whites. The mean and median serum glucose levels at the time of hospital admission were 171.4 mg/dl and 143.0, respectively. Hyperglycemia was present in 51.9% of patients at the time of hospital admission; VT occurred in 652 patients (15.8%), and two-thirds of these episodes occurred during the first 48 h after hospital admission (early VT). After multivariable adjustment, patients with hyperglycemia were at increased risk for developing VT (adjusted OR = 1.48, 95% CI = 1.23–1.78). The presence of hyperglycemia was significantly associated with early (multivariable adjusted OR = 1.39, 95% CI = 1.11–1.73) but not with late VT. Similar associations were observed in patients with and without diabetes and in patients with and without ST-segment elevation AMI.

Conclusions

Efforts should be made to closely monitor and treat patients who develop hyperglycemia, especially early after hospital admission, to reduce their risk of VT.

Integrated optical coherence tomography and multielement ultrasound transducer probe for shear wave elasticity imaging of moving tissues

Accurate measurements of microelastic properties of soft tissues in-vivo using optical coherence elastography can be affected by motion artifacts caused by cardiac and respiratory cycles. This problem can be overcome using a multielement ultrasound transducer probe where each ultrasound transducer is capable of generating acoustic radiation force (ARF) and, therefore, creating shear waves in tissue. These shear waves, produced during the phase of cardiac and respiratory cycles when tissues are effectively stationary, are detected at the same observation point using phase-sensitive optical coherence tomography (psOCT). Given the known distance between the ultrasound transducers, the speed of shear wave propagation can be calculated by measuring the difference between arrival times of shear waves. The combined multitransducer ARF/psOCT probe has been designed and tested in phantoms and ex-vivo studies using fresh rabbit heart. The measured values of shear moduli are in good agreement with those reported in literature. Our results suggest that the developed multitransducer ARF/psOCT probe can be useful for many in-vivo applications, including quantifying the microelasticity of cardiac muscle.

After the LEADER trial and SUSTAIN-6, how do we explain the cardiovascular benefits of some GLP-1 receptor agonists?

Recent cardiovascular outcome trials - the LEADER with liragutide and SUSTAIN-6 with semaglutide - have shown significant reductions of major cardiovascular (CV) events with these glucagon-like peptide (GLP)-1 receptor agonists. Progressive separation of the treatment and placebo curves, starting clearly between 12 and 18 months of the trial period, and significant reductions in the risk of myocardial infarction and stroke, indicate that the beneficial CV effects observed with GLP-1 receptor agonists could be due to an antiatherogenic effect. So far, the reasons for such an effect of GLP-1 receptor agonists have not been entirely clear, although several hypotheses may be proposed. As the reductions in glycated haemoglobin and systolic blood pressure (SBP) in these trials were modest, and both trials lasted only a short period of time, reductions in hyperglycaemia and SBP are unlikely to be involved in the beneficial CV effects of GLP-1 receptor agonists. On the other hand, their effect on lipids and, in particular, the dramatic decrease in postprandial hypertriglyceridaemia may explain their beneficial CV actions. Reduction of body weight, including a significant decrease in visceral fat in patients using GLP-1 receptor agonists, may also have beneficial CV effects by reducing chronic proatherogenic inflammation. In addition, there are in-vitro data showing a direct anti-inflammatory effect with these agents that could also be involved in their beneficial CV effects. Moreover, studies in humans have shown significant beneficial effects on ischaemic myocardium after a very short treatment period, suggesting a direct effect of GLP-1 receptor agonists on myocardium, although the precise mechanism remains unclear. Finally, as a reduction in insulin resistance has been associated with a decrease in CV risk, it cannot be ruled out that the lowering of insulin resistance induced by GLP-1 receptor agonists might also be involved in their beneficial CV actions.

Myocyte membrane and microdomain modifications in diabetes: determinants of ischemic tolerance and cardioprotection

Cardiovascular disease, predominantly ischemic heart disease (IHD), is the leading cause of death in diabetes mellitus (DM). In addition to eliciting cardiomyopathy, DM induces a ‘wicked triumvirate’: (i) increasing the risk and incidence of IHD and myocardial ischemia; (ii) decreasing myocardial tolerance to ischemia–reperfusion (I–R) injury; and (iii) inhibiting or eliminating responses to cardioprotective stimuli. Changes in ischemic tolerance and cardioprotective signaling may contribute to substantially higher mortality and morbidity following ischemic insult in DM patients. Among the diverse mechanisms implicated in diabetic impairment of ischemic tolerance and cardioprotection, changes in sarcolemmal makeup may play an overarching role and are considered in detail in the current review. Observations predominantly in animal models reveal DM-dependent changes in membrane lipid composition (cholesterol and triglyceride accumulation, fatty acid saturation vs. reduced desaturation, phospholipid remodeling) that contribute to modulation of caveolar domains, gap junctions and T-tubules. These modifications influence sarcolemmal biophysical properties, receptor and phospholipid signaling, ion channel and transporter functions, contributing to contractile and electrophysiological dysfunction, cardiomyopathy, ischemic intolerance and suppression of protective signaling. A better understanding of these sarcolemmal abnormalities in types I and II DM (T1DM, T2DM) can inform approaches to limiting cardiomyopathy, associated IHD and their consequences. Key knowledge gaps include details of sarcolemmal changes in models of T2DM, temporal patterns of lipid, microdomain and T-tubule changes during disease development, and the precise impacts of these diverse sarcolemmal modifications. Importantly, exercise, dietary, pharmacological and gene approaches have potential for improving sarcolemmal makeup, and thus myocyte function and stress-resistance in this ubiquitous metabolic disorder.

Prognostic value of glucose metabolism for non-ST-segment elevation infarction patients with diabetes mellitus and single concomitant chronic total occlusion following primary percutaneous coronary intervention

Glucose metabolism status may play a predictive role in the severity of the complications among patients with type 2 diabetes mellitus (DM). However, few studies have focused on the prognostic value of glycosylated hemoglobin (HbA1c) and Homeostatic Model Assessment 2 for Insulin Resistance (HOMA2-IR) in patients with DM, non-ST-segment elevation infarction (NSTEMI), and single concomitant chronic total occlusion (CTO) following primary percutaneous coronary intervention (PCI). Short- and long-term prognostic value of HbA1c and HOMA2-IR in patients with DM with NSTEMI and single CTO who received primary percutaneous transluminal coronary intervention (pPCI).Data from 202 patients with NSTEMI and single CTO in nonculprit vessels were included. The incidence of revascularization, cardiogenic shock, ischemic stroke, major bleeding (ie, cerebral hemorrhage or massive hemorrhage of gastrointestinal tract), and cardiac death were combined as composite end points (CEPs). HbA1c was measured on admission and at 12 and 24 weeks after discharge. HOMA2-IR was measured on admission and at 6 and 12 weeks after discharge. The mean value of HbA1c and HOMA2-IR was calculated to determine the impact on 2.5-year CEPs. All patients were assessed during hospitalization and followed for up to 2.5 years after discharge.Mean age was 62.4 ± 11.8 years and 76% were male. Previous MI, lower left ventricular ejection fraction, and higher HbA1c (hazard ratio [HR] = 1.216; 95% confidence interval [CI] = 1.023-1.445; P = .023) were independently associated with a poor prognosis at 2.5 years. Higher HbA1c and HOMA2-IR on admission was associated with CEPs during hospitalization. Mean HOMA2-IR prior to pPCI was associated with revascularization (HR = 1.129; 95% CI = 1.008-1.265; P = .036) and ischemic stroke (HR = 1.276; 95% CI = 1.044-1.560; P = .017) during the 2.5 years follow-up period.Glucose metabolism status reflected by HbA1c and HOMA2-IR may provide prognostic value to patients with NSTEMI, type 2 DM, and single concomitant CTO following PCI. Therefore, patients with NSTEMI, CTO, and poor glycemic control should be carefully evaluated prior to PCI.

Elevating VEGF-A and PDGF-BB secretion by salidroside enhances neoangiogenesis in diabetic hind-limb ischemia

Hind-limb ischemia (HLI) is one of the major complication of diabetic patients. Angiogenesis potential in diabetic patients is severely disrupted, and the mechanism underlying it has not been fully elucidated, making it an obstacle for developing an efficient therapeutic angiogenesis strategy. Skeletal muscle cells, through their paracrine function, had been known to be critical for neoangiogenesis. Here we found that hyperglycemia upregulates the expression of skeletal muscle cells prolyl hydroxylase domain 3 (PHD3), which resulted in the decrease of the secretion of angiogenic factors, especially VEGF-A and PDGF-BB. We showed that treatment with salidroside, a small molecule drug, significantly suppresses PHD3 expression and increases VEGF-A and PDGF-BB secretion from skeletal muscle cells, which in turn enhances the proliferation and migration potentials of endothelial and smooth muscle cells. Finally, we demonstrated that intramuscular injection of salidroside into the ischemic hind limbs of diabetic HLI model mice could efficiently induce neoangiogenesis and blood perfusion recovery. Thus, our novel findings not only reveal the effects of hyperglycemia on the angiogenesis potential of skeletal muscle cells and the mechanism underlying it, but also provides a novel finding suggesting that salidroside might be a potential small molecule drug for diabetic HLI.

A meta-analysis on the correlation between admission hyperglycemia and myocardial infarct size on CMRI

AIMS

The aim was to compare the size of the myocardial infarct detected on cardiovascular magnetic resonance imaging (CMR) between patients with and without admission hyperglycemia after acute myocardial infarction (AMI).

METHODS

Studies were identified by searching on MEDLINE, EMBASE, and CINAHL databases. A systematic review was conducted by two independent reviewers. Microvascular obstruction (MVO) and late gadolinium enhancement (LGE) were pooled from available studies to calculate the standardized mean difference (SMD) in post-MI infarct size between patients with and without hyperglycemia at admission.

RESULTS

The systematic review yielded 5 studies with MCR data for patients with and without admission hyperglycemia. The total number of patients included in this study was 911. A statistically significant difference was detected in MVO between patients with and without admission hyperglycemia (SMD = 0.79, 95% CI: 0.11, 1.47, P < 0.00001). The difference in LGE between patients with and without admission hyperglycemia was also significant (SMD = 0.57, 95% CI: -0.04, 1.18, P < 0.00001).

CONCLUSION

The main finding of our analyses is that the size of myocardial infarct detected on CMR is positively correlated to admission hyperglycemia in patients with AMI. The clinical importance of this study lies in the accurate assessment of prognostic value of admission glucose, which would help clinicians in risk stratification and treatment decision-making.

Anthocyanins from Purple Corn Ameliorated Tumor Necrosis Factor-α-Induced Inflammation and Insulin Resistance in 3T3-L1 Adipocytes via Activation of Insulin Signaling and Enhanced GLUT4 Translocation

SCOPE

The aim was to compare the effect of an anthocyanin-rich extract from purple corn pericarp (PCW) and pure anthocyanins on adipogenesis, inflammation, and insulin resistance in 3T3-L1 adipocytes on basal and inflammatory conditions.

METHODS AND RESULTS

Preadipocytes (3T3-L1) were treated during differentiation with or without PCW. Differentiated adipocytes were treated either individually or in combination with tumor necrosis factor α (TNF-α) and PCW, or pure C3G, Pr3G, P3G. PCW reduced preadipocyte differentiation (IC₅₀ = 0.4 mg/mL). PCW and pure anthocyanins including C3G reduced fatty acid synthase enzymatic activity. PCW reduced TNF-α-dependent inflammatory status increasing adiponectin (39%), and decreasing leptin (-79%). PCW and C3G increased glucose uptake and reduced reactive oxygen species generation in insulin resistant adipocytes. An increase in phosphorylation was observed in AKT, IKK, and MEK, and a decrease in IRS and mTOR activating the insulin receptor-associated pathway. PCW (7.5-fold) and C3G (6.3-fold) enhanced GLUT4 membrane translocation compared to insulin resistant adipocytes.

CONCLUSION

Anthocyanins from colored corn prevented adipocyte differentiation, lipid accumulation, and reduced PPAR-γ transcriptional activity on adipocytes in basal conditions. Ameliorated TNF-α-induced inflammation and insulin resistance in adipocytes via activation of insulin signaling and enhanced GLUT4 translocation suggesting a reduced hyperglycemia associated with the metabolic syndrome.

Synergistic effects of metformin with liraglutide against endothelial dysfunction through GLP-1 receptor and PKA signalling pathway

Metformin or glucagon-like peptide-1 (GLP-1) analogue liraglutide has cardiovascular benefits. However, it is not clear whether their combined treatment have additive or synergistic effects on the vasculature. In this study, human umbilical vein endothelial cells (HUVECs), exposed to palmitic acid (PA) to induce endothelial dysfunction, were incubated with metformin, liraglutide or their combination. High fat diet (HFD)-fed ApoE^−/− mice were randomized into control, metformin, liraglutide, and combination treatment groups. Results showed that in PA-treated HUVECs and HFD-fed ApoE^−/− mice, combination of metformin and liraglutide at lower dose significantly improved endothelial dysfunction compared with the single treatment. Metformin upregulated GLP-1 receptor (GLP-1R) level and protein kinase A (PKA) phosphorylation. However, PKA inhibition but not GLP-1R blockade eliminated the protective effects of metformin on endothelial function. Furthermore, AMPK inhibitor compound C abolished the metformin-mediated upregulation of GLP-1R level and PKA phosphorylation. In conclusion, combination of metformin and liraglutide has synergistic protective effects on endothelial function. Moreover, metformin stimulates GLP-1R and PKA signalling via AMPK-dependent pathway, which may account for its synergistic protective effects with liraglutide. Our findings provide new insights on the interaction between metformin and GLP-1, and provide important information for designing new GLP-1-based therapy strategies in treating type 2 diabetes.

Admission hyperglycemia and adverse outcomes in diabetic and non-diabetic patients with non-ST-elevation myocardial infarction undergoing percutaneous coronary intervention

Background

The association between admission hyperglycemia and adverse outcomes in patients with non-ST-segment elevation myocardial infarction (NSTEMI) undergoing percutaneous coronary intervention (PCI) has not been well studied, and the optimal plasma glucose cut-off values for prognosis for NSTEMI patients with and without diabetes have not been determined.

Methods

According to glucose level and diabetes status, consecutive NSTEMI patients undergoing PCI (n = 890) were divided into four groups: without diabetes mellitus (DM) and admission plasma glucose (APG) <144 or ≥144 mg/dL; or with DM and APG <180 or ≥180 mg/dL. All patients were followed up at 30 days and 3 years after discharge, and the outcomes were assessed.

Results

Admission hyperglycemia was found in 44 and 28% of the DM and non-DM patients, respectively. Multivariable analyses showed that the APG level was an independent predictor of 30-day and 3-year MACEs. Receiver operating characteristic curve analysis revealed that the appropriate cut-off values were 178 and 145 mg/dL for patients with and without DM, respectively, or 157 mg/dL for all patients.

Conclusions

Admission hyperglycemia may be used to predict 30-day and 3-year MACEs in patients with NSTEMI undergoing PCI, irrespective of diabetes status. However, the optimal admission glucose cut-off values for predicting prognosis differ for patients with or without DM.

Melatonin rescues cardiac thioredoxin system during ischemia-reperfusion injury in acute hyperglycemic state by restoring Notch1/Hes1/Akt signaling in a membrane receptor-dependent manner

Stress hyperglycemia is commonly observed in patients suffering from ischemic heart disease. It not only worsens cardiovascular prognosis but also attenuates the efficacies of various cardioprotective agents. This study aimed to investigate the protective effect of melatonin against myocardial ischemia-reperfusion (MI/R) injury in acute hyperglycemic state with a focus on Notch1/Hes1/Akt signaling and intracellular thioredoxin (Trx) system. Sprague Dawley rats were subjected to MI/R surgery and high-glucose (HG, 500 g/L) infusion (4 mL/kg/h) to induce temporary hyperglycemia. Rats were treated with or without melatonin (10 mg/kg/d) during the operation. Furthermore, HG (33 mmol/L)-incubated H9c2 cardiomyoblasts were treated in the presence or absence of luzindole (a competitive melatonin receptor antagonist), DAPT (a γ-secretase inhibitor), LY294002 (a PI3-kinase/Akt inhibitor), or thioredoxin-interacting protein (Txnip) adenoviral vectors. We found that acute hyperglycemia aggravated MI/R injury by suppressing Notch1/Hes1/Akt signaling and intracellular Trx activity. Melatonin treatment effectively ameliorated MI/R injury by reducing infarct size, myocardial apoptosis, and oxidative stress. Moreover, melatonin also markedly enhanced Notch1/Hes1/Akt signaling and rescued intracellular Trx system by upregulating Notch1, N1ICD, Hes1, and p-Akt expressions, increasing Trx activity, and downregulating Txnip expression. However, these effects were blunted by luzindole, DAPT, or LY294002. Additionally, Txnip overexpression not only decreased Trx activity, but also attenuated the cytoprotective effect of melatonin. We conclude that impaired Notch1 signaling aggravates MI/R injury in acute hyperglycemic state. Melatonin rescues Trx system by reducing Txnip expression via Notch1/Hes1/Akt signaling in a membrane receptor-dependent manner. Its role as a prophylactic/therapeutic drug deserves further clinical study.

Pleiotropic effects of insulin and GLP-1 receptor agonists: Potential benefits of the association

The combination of basal insulin and glucagon-like peptide-1 receptor agonists (GLP-1RAs) is an emerging option for patients with type 2 diabetes (T2D). GLP-1RAs have been shown to improve glycaemic control with a low risk of hypoglycaemia and to promote body weight loss. However, GLP-1 receptors (GLP-1Rs) are widely expressed in extrapancreatic tissues and could sustain pleiotropic actions of GLP-1RAs beyond glycaemic control. The underlying molecular mechanisms maintaining these extrapancreatic actions of GLP-1 are complex, and involve GLP-1R signalling in both the brain and several peripheral tissues. The present review focuses specifically on the role of GLP-1RAs in the cardiovascular system and liver. Preclinical data in rodents and pilot studies in humans suggest that GLP-1RAs may have potential beneficial effects on heart function, blood pressure, postprandial lipaemia, liver steatosis and non-alcoholic steatohepatitis (NASH). Long-term studies are now warranted to determine the safety and clinical relevance of the association between insulin and GLP-1RAs in T2D.

The Cardiovascular Biology of Glucagon-like Peptide-1

Glucagon-like peptide-1, produced predominantly in enteroendocrine cells, controls glucose metabolism and energy homeostasis through regulation of islet hormone secretion, gastrointestinal motility, and food intake, enabling development of GLP-1 receptor (GLP-1R) agonists for the treatment of diabetes and obesity. GLP-1 also acts on the immune system to suppress inflammation, and GLP-1R signaling in multiple tissues impacts cardiovascular function in health and disease. Here we review how GLP-1 and clinically approved GLP-1R agonists engage mechanisms that influence the risk of developing cardiovascular disease. We discuss how GLP-1R agonists modify inflammation, cardiovascular physiology, and pathophysiology in normal and diabetic animals through direct and indirect mechanisms and review human studies illustrating mechanisms linking GLP-1R signaling to modification of the cardiovascular complications of diabetes. The risks and benefits of GLP-1R agonists are updated in light of recent data suggesting that GLP-1R agonists favorably modify outcomes in diabetic subjects at high risk for cardiovascular events.

Comparison Review of Short-Acting and Long-Acting Glucagon-like Peptide-1 Receptor Agonists

Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs) are useful tools for treating type 2 diabetes mellitus. In their recent position statement, the American Diabetes Association and European Association for the Study of Diabetes recommend GLP1-RAs as add-on to metformin when therapeutic goals are not achieved with monotherapy, particularly for patients who wish to avoid weight gain or hypoglycemia. GLP1-RAs differ substantially in their duration of action, frequency of administration and clinical profile. Members of this class approved for clinical use include exenatide twice-daily, exenatide once-weekly, liraglutide and lixisenatide once-daily. Recently, two new once-weekly GLP1-RAs have been approved: dulaglutide and albiglutide. This article summarizes properties of short- and long-acting GLP-1 analogs, and provides useful information to help choose the most appropriate compound for individual patients.

Targeting reperfusion injury in the era of primary percutaneous coronary intervention: hope or hype?

Introduction of reperfusion therapy by primary percutaneous coronary intervention (PCI) has resulted in improved outcomes for patients presenting with ST-segment elevation myocardial infarction. Despite the obvious advantages of primary PCI, acute restoration of blood flow paradoxically also jeopardises the myocardium in the first minutes of reperfusion-a phenomenon known as reperfusion injury. Prevention of reperfusion injury may help to improve outcome following primary PCI. This review focuses on the clinical evidence of potential therapeutic cardioprotective methods as adjuvant to primary PCI. Despite overall disappointing, there exists some promising strategies, including ischaemic postconditioning, remote ischaemic conditioning, pharmacological conditioning with focus on adenosine, cyclosporine A, glucose-insulin-potassium, exenatide, atrial natriuretic peptide and metoprolol and cooling. But hitherto no large randomised study has demonstrated any effect on outcome, and ongoing studies that address this issue are underway. Moreover, this review will discuss important clinical predictors associated with reperfusion injury during primary PCI that may interfere with a potential protective effect (pre-PCI thrombolysis in myocardial infarction flow, preinfarction angina, collateral flow, duration of ischaemia and hyperglycaemia). This paper will also provide a short overview of the technical issues related to surrogate endpoints in phase II trials. Based upon these discussions, the paper will provide factors that should be taken into account when designing future clinical studies.

Potential role of dipeptidyl peptidase IV in the pathophysiology of heart failure

Dipeptidyl peptidase IV (DPPIV) is a widely expressed multifunctional serine peptidase that exists as a membrane-anchored cell surface protein or in a soluble form in the plasma and other body fluids. Numerous substrates are cleaved at the penultimate amino acid by DPPIV, including glucagon-like peptide-1 (GLP-1), brain natriuretic peptide (BNP) and stromal cell-derived factor-1 (SDF-α), all of which play important roles in the cardiovascular system. In this regard, recent reports have documented that circulating DPPIV activity correlates with poorer cardiovascular outcomes in human and experimental heart failure (HF). Moreover, emerging evidence indicates that DPPIV inhibitors exert cardioprotective and renoprotective actions in a variety of experimental models of cardiac dysfunction. On the other hand, conflicting results have been found when translating these promising findings from preclinical animal models to clinical therapy. In this review, we discuss how DPPIV might be involved in the cardio-renal axis in HF. In addition, the potential role for DPPIV inhibitors in ameliorating heart disease is revised, focusing on the effects of the main DPPIV substrates on cardiac remodeling and renal handling of salt and water.

Antidiabetic therapy in post kidney transplantation diabetes mellitus

Post-transplantation diabetes mellitus (PTDM) is a common complication after kidney transplantation that affects up to 40% of kidney transplant recipients. By pathogenesis, PTDM is a diabetes form of its own, and may be characterised by a sudden, drug-induced deficiency in insulin secretion rather than worsening of insulin resistance over time. In the context of deteriorating allograft function leading to a re-occurrence of chronic kidney disease after transplantation, pharmacological interventions in PTDM patients deserve special attention. In the present review, we aim at presenting the current evidence regarding efficacy and safety of the modern antidiabetic armamentarium. Specifically, we focus on incretin-based therapies and insulin treatment, besides metformin and glitazones, and discuss their respective advantages and pitfalls. Although recent pilot trials are available in both prediabetes and PTDM, further studies are warranted to elucidate the ideal timing of various antidiabetics as well as its long-term impact on safety, glucose metabolism and cardiovascular outcomes in kidney transplant recipients.

Stimulation of glucagon-like peptide-1 receptor through exendin-4 preserves myocardial performance and prevents cardiac remodeling in infarcted myocardium

We have demonstrated that GLP-1 improved myocardial functional recovery in acute myocardial ischemic injury. However, whether stimulation of the GLP-1 receptor (GLP-1R) with exendin-4, a selective GLP-1R agonist, could initiate a protective effect in the heart remains to be determined. Mouse myocardial infarction (MI) was created by ligation of the left descending artery. After 48 h of MI, animals were divided into the following groups (n = 5-7/group): 1) sham (animals that underwent thoracotomy without ligation), 2) MI [animals that underwent MI and received a daily dose of intraperitoneal injection (ip) of saline]; and 3) MI + exendin-4 [infarcted mice that received injections of exendin-4 (0.1 mg/kg ip)]. Two weeks later, cardiac function was assessed by echocardiography and an isovolumetrically perfused heart. Compared with control MI hearts, stimulation of GLP-1R improved cardiac function, which was associated with attenuation of myocardial hypertrophy, the mitigation of interstitial fibrosis, and an increase in survival rate in post-MI hearts. Furthermore, H9c2 cardiomyoblasts were preconditioned with exendin-4 at a dose of 100 nmol/l and then subjected to hydrogen peroxide exposure at concentrations of 50 and 100 μmol/l. The exendin-4 treatment decreased lactate dehydrogenase leakage and increased cell survival. Notably, this event was also associated with the reduction of cleaved caspase-3 and caspase-9 and attenuation of reactive oxygen species production. Exendin-4 treatments improved mitochondrial respiration and suppressed the opening of mitochondrial permeability transition pore and protected mitochondria function. Our results indicate that GLP-1R serves as a novel approach to eliciting cardioprotection and mitigating oxidative stress-induced injury.

Exendin-4 ameliorates cardiac ischemia/reperfusion injury via caveolae and caveolins-3

Background

Exendin-4, an exogenous glucagon-like peptide-1 receptor (GLP-1R) agonist, protects the heart from ischemia/reperfusion injury. However, the mechanisms for this protection are poorly understood. Caveolae, sarcolemmal invaginations, and caveolins, scaffolding proteins in caveolae, localize molecules involved in cardiac protection. We tested the hypothesis that caveolae and caveolins are essential for exendin-4 induced cardiac protection using in vitro and in vivo studies in control and caveolin-3 (Cav-3) knockout mice (Cav-3 KO).

Methods

Myocytes were treated with exendin-4 and then incubated with methyl-β-cyclodextrin (MβCD) to disrupt caveolae formation. This was then followed by simulated ischemia/reperfusion (SI/R). In addition, cardiac protection in vivo was assessed by measuring infarct size and cardiac troponin levels.

Results

Exendin-4 protected cardiac myocytes (CM) from SI/R [35.6 ± 12.6% vs. 64.4 ± 18.0% cell death, P = 0.034] and apoptosis but this protection was abolished by MβCD (71.8 ± 10.8% cell death, P = 0.004). Furthermore, Cav-3/GLP-1R co-localization was observed and membrane fractionation by sucrose density gradient centrifugation of CM treated with MβCD + exendin-4 revealed that buoyant (caveolae enriched) fractions decreased Cav-3 compared to CM treated with exendin-4 exclusively. Furthermore, exendin-4 induced a reduction in infarct size and cardiac troponin relative to control (infarct size: 25.1 ± 8.2% vs. 41.4 ± 4.1%, P < 0.001; troponin: 36.9 ± 14.2 vs. 101.1 ± 22.3 ng/ml, P < 0.001). However, exendin-4 induced cardiac protection was abolished in Cav-3 KO mice (infarct size: 43.0 ± 6.4%, P < 0.001; troponin: 96.8 ± 26.6 ng/ml, P = 0.001).

Conclusions

We conclude that caveolae and caveolin-3 are critical for exendin-4 induced protection of the heart from ischemia/reperfusion injury.

EphA2-receptor deficiency exacerbates myocardial infarction and reduces survival in hyperglycemic mice

Background

We have previously shown that EphrinA1/EphA expression profile changes in response to myocardial infarction (MI), exogenous EphrinA1-Fc administration following MI positively influences wound healing, and that deletion of the EphA2 Receptor (EphA2-R) exacerbates injury and remodeling. To determine whether or not ephrinA1-Fc would be of therapeutic value in the hyperglycemic infarcted heart, it is critical to evaluate how ephrinA1/EphA signaling changes in the hyperglycemic myocardium in response to MI.

Methods

Streptozotocin (STZ)-induced hyperglycemia in wild type (WT) and EphA2-receptor mutant (EphA2-R-M) mice was initiated by an intraperitoneal injection of STZ (150 mg/kg) 10 days before surgery. MI was induced by permanent ligation of the left anterior descending coronary artery and analyses were performed at 4 days post-MI. ANOVAs with Student-Newman Keuls multiple comparison post-hoc analysis illustrated which groups were significantly different, with significance of at least p < 0.05.

Results

Both WT and EphA2-R-M mice responded adversely to STZ, but only hyperglycemic EphA2-R-M mice had lower ejection fraction (EF) and fractional shortening (FS). At 4 days post-MI, we observed greater post-MI mortality in EphA2-R-M mice compared with WT and this was greater still in the EphA2-R-M hyperglycemic mice. Although infarct size was greater in hyperglycemic WT mice vs normoglycemic mice, there was no difference between hyperglycemic EphA2-R-M mice and normoglycemic EphA2-R-M mice. The hypertrophic response that normally occurs in viable myocardium remote to the infarct was noticeably absent in epicardial cardiomyocytes and cardiac dysfunction worsened in hyperglycemic EphA2-R-M hearts post-MI. The characteristic interstitial fibrotic response in the compensating myocardium remote to the infarct also did not occur in hyperglycemic EphA2-R-M mouse hearts to the same extent as that observed in the hyperglycemic WT mouse hearts. Differences in neutrophil and pan-leukocyte infiltration and serum cytokines implicate EphA2-R in modulation of injury and the differences in ephrinA1 and EphA6-R expression in governing this are discussed.

Conclusions

We conclude that EphA2-mutant mice are more prone to hyperglycemia-induced increased injury, decreased survival, and worsened LV remodeling due to impaired wound healing.