exenatide and Myocardial-Infarction

There is a need to find interventions able to reduce the extent of injury in reperfused ST-segment elevation myocardial infarction (STEMI) beyond timely reperfusion. In this review, we summarise the clinical impact of STEMI from epidemiological, clinical and biological perspectives. We also revise the pathophysiology underlying the ischaemia/reperfusion syndrome occurring in reperfused STEMI, including the several players involved in this syndrome, such as cardiomyocytes, microcirculation and circulating cells. Interventions aimed to reduce the resultant infarct size, known as cardioprotective therapies, are extensively discussed, putting the focus on both mechanical interventions (i.e. ischaemic conditioning) and promising pharmacological therapies, such as early intravenous metoprolol, exenatide and other glucose modulators, N-acetylcysteine as well as on some other classic therapies which have failed to be translated to the clinical arena. Novel targets for evolving therapeutic interventions to ameliorate ischaemia/reperfusion injury are also discussed. Finally, we highlight the necessity to improve the study design of future randomised clinical trials in the field, as well as to select patients better who can most likely benefit from cardioprotective interventions.

Topics: Acetylcysteine; Acute Disease; Administration, Intravenous; Adrenergic beta-1 Receptor Antagonists; Animals; Cardiotonic Agents; Exenatide; Free Radical Scavengers; Humans; Hypoglycemic Agents; Incidence; Metoprolol; Mice; Mice, Transgenic; Microcirculation; Models, Animal; Myocardial Infarction; Myocardial Reperfusion Injury; Myocytes, Cardiac; Percutaneous Coronary Intervention; Randomized Controlled Trials as Topic; ST Elevation Myocardial Infarction

Studies designed to evaluate the short-term effects of incretin-related drugs in subjects with cardiac disease are still preliminary. In patients with heart failure, two of five studies showed that glucagon-like peptide-1 (GLP-1) infusion was associated with an absolute increase in left ventricular ejection fraction (LVEF) by 6-10 %, whereas no significant benefit was observed in the remaining three studies. In patients with coronary artery disease, single infusion of the GLP-1 receptor analog, exenatide, did not increase LVEF, but this drug may decrease infarct size in patients with myocardial infarction presenting with short duration of ischemic symptoms. Single dose of GLP-1 and the dipeptidyl-peptidase-IV (DPP-IV) inhibitor, sitagliptin, may improve left ventricular function, predominantly in ischemic segments, and attenuate post-ischemic stunning. Nausea, vomiting and hypoglycemia were the most common adverse effects associated with GLP-1 and exenatide administration. Increased heart rate was also observed with exenatide in patients with heart failure. Large randomized trials including diabetic patients with preexisting heart failure and myocardial infarction showed that chronic therapy with the DPP-IV inhibitors saxagliptin and alogliptin did not reduce cardiovascular events or mortality. Moreover, saxagliptin use was associated with significant increase in frequency of heart failure requiring hospitalization, hypoglycemia and angioedema. Overall, short-term preliminary data suggest potential cardioprotective effects of exenatide and sitagliptin in patients with heart failure and myocardial infarction. Meanwhile, long-term randomized trials suggest no benefit of alogliptin, and increased harm associated with the use of saxagliptin.

Topics: Animals; Cardiotonic Agents; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Exenatide; Glucagon-Like Peptide 1; Heart Failure; Humans; Hypoglycemic Agents; Incretins; Myocardial Infarction; Peptides; Venoms

To examine sex differences in the characteristics and outcomes in participants with type 2 diabetes (T2D), with or without cardiovascular disease (CVD), randomized to once-weekly exenatide (EQW) or placebo in the Exenatide Study of Cardiovascular Event Lowering (EXSCEL).. Baseline characteristics were summarized and compared by sex. Cox proportional hazards regression models were used for clinical outcomes, including the primary composite outcome of cardiovascular (CV) death, non-fatal myocardial infarction or non-fatal stroke (MACE3). Models including sex-by-treatment interaction were used to evaluate differences in effects of EQW.. Overall, 5603 women and 9149 men were followed for a median of 3.2 years. Women were younger (mean 61.4 vs. 62.2 years, P < .001) and had a shorter duration of diabetes (mean 12.9 vs. 13.2 years, P = .039) and less coronary artery disease (35.2% vs. 61.0%, P < .001) than men, but also a less favourable metabolic risk profile and lower use of cardioprotective medications. MACE3 occurred in 9.1% of women and 13.5% of men, corresponding to 2.82 versus 4.40 events/100 participant-years (adjusted hazard ratio 0.80, 95% CI: 0.70-0.93, P = .003). There was no difference in MACE3 with EQW compared with placebo, or evidence of heterogeneity of treatment effect by sex.. This analysis of a large population of individuals with T2D, with or without established CVD, identified between-sex differences in clinical characteristics and care. Despite having worse management of CV risk factors, women had significantly lower rates of important CV events not attributable to the effects of study treatment.

Topics: Diabetes Mellitus, Type 2; Exenatide; Female; Humans; Hypoglycemic Agents; Male; Myocardial Infarction; Risk Factors; Sex Characteristics

We sought to confirm a bidirectional association between severe hypoglycemic events (SHEs) and cardiovascular (CV) event risk and to characterize individuals at dual risk.. In a post hoc analysis of 14,752 Exenatide Study of Cardiovascular Event Lowering (EXSCEL) participants, we examined time-dependent associations between SHEs and subsequent major adverse cardiac events (CV death, nonfatal myocardial infarction [MI] or stroke), fatal/nonfatal MI, fatal/nonfatal stroke, hospitalization for acute coronary syndrome (hACS), hospitalization for heart failure (hHF), and all-cause mortality (ACM), as well as time-dependent associations between nonfatal CV events and subsequent SHEs.. SHEs were uncommon and not associated with once-weekly exenatide therapy (hazard ratio 1.13 [95% CI 0.94-1.36],. These findings, showing greater risk of SHEs after CV events as well as greater risk of CV events after SHEs, validate a bidirectional relationship between CV events and SHEs in patients with high comorbidity scores.

Topics: Acute Coronary Syndrome; Aged; Cardiovascular Diseases; Comorbidity; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Double-Blind Method; Exenatide; Female; Hospitalization; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Middle Aged; Myocardial Infarction; Risk Factors; Severity of Illness Index; Stroke

Recent trials have identified anti-diabetes mellitus agents that lower major adverse cardiovascular event (MACE) rates, although some increase rates of lower-extremity amputation (LEA). Patients with peripheral artery disease (PAD) have greater incidence of diabetes mellitus and risk for LEA, prompting this investigation of clinical outcomes in patients with diabetes mellitus and PAD in the EXSCEL trial (Exenatide Study of Cardiovascular Event Lowering).. EXSCEL evaluated the effects of once-weekly exenatide (a GLP-1 [glucagon-like peptide-1] receptor agonist) versus placebo on the rates of the primary composite MACE end point (cardiovascular death, myocardial infarction, or stroke) among patients with type 2 diabetes mellitus. In this post hoc analysis, we assessed the association of baseline PAD with rates of MACE, LEA, and the effects of exenatide versus placebo in patients with and without PAD.. EXSCEL included 2800 patients with PAD (19% of the trial population). These individuals had higher unadjusted and adjusted rates of MACE compared with patients without PAD (13.6% versus 11.4%, respectively) as well as a higher adjusted hazard ratio (adjusted hazard ratio, 1.13 [95% CI, 1.00-1.27];. EXSCEL participants with PAD had higher rates of all-cause mortality and LEA compared with those without PAD. There were no differences in MACE or LEA rates with exenatide versus placebo. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT01144338.

Topics: Aged; Cause of Death; Diabetes Mellitus, Type 2; Double-Blind Method; Exenatide; Female; Glucagon-Like Peptide-1 Receptor; Humans; Hypoglycemic Agents; Incretins; Male; Middle Aged; Myocardial Infarction; Peripheral Arterial Disease; Risk Assessment; Risk Factors; Stroke; Time Factors; Treatment Outcome

EXSCEL is a randomized, double-blind, placebo-controlled trial examining the effect of exenatide once-weekly (EQW) versus placebo on time to the primary composite outcome (cardiovascular death, nonfatal myocardial infarction or nonfatal stroke) in patients with type 2 diabetes mellitus (DM) and a wide range of cardiovascular (CV) risk.. Patients were enrolled at 688 sites in 35 countries. We describe their baseline characteristics according to prior CV event status and compare patients with those enrolled in prior glucagon-like peptide-1 receptor agonist (GLP-1RA) outcomes trials.. Of a total of 14,752 participants randomized between June 2010 and September 2015, 6,788 (46.0%) patients were enrolled in Europe; 3,708 (25.1%), North America; 2,727 (18.5%), Latin America; and 1,529 (10.4%), Asia Pacific. Overall, 73% had at least one prior CV event (70% coronary artery disease, 24% peripheral arterial disease, 22% cerebrovascular disease). The median (IQR) age was 63 years (56, 69), 38% were female, median baseline HbA1c was 8.0% (7.3, 8.9) and 16% had a prior history of heart failure. Those without a prior CV event were younger with a shorter duration of diabetes and better renal function than those with at least one prior CV event. Compared with prior GLP-1RA trials, EXSCEL has a larger percentage of patients without a prior CV event and a notable percentage who were taking a dipeptidyl peptidase-4 inhibitor at baseline (15%).. EXSCEL is one of the largest global GLP-1RA trials, evaluating the safety and efficacy of EQW with a broad patient population that may extend generalizability compared to prior GLP-1RA trials (ClinicalTrials.gov number, NCT01144338).

Topics: Aged; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Double-Blind Method; Exenatide; Female; Glucagon-Like Peptide-1 Receptor; Humans; Hypoglycemic Agents; Male; Middle Aged; Myocardial Infarction; Peptides; Risk Factors; Stroke; Venoms

This double blinded, placebo controlled randomized clinical trial studies the effect of exenatide on myocardial infarct size. The glucagon-like peptide-1 receptor agonist exenatide has possible cardioprotective properties during reperfusion after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction.. 191 patients were randomly assigned to intravenous exenatide or placebo initiated prior to percutaneous coronary intervention using 10μg/h for 30min followed by 0.84μg/h for 72h. Patients with a previous myocardial infarction, Trombolysis in Myocardial Infarction flow 2 or 3, multi-vessel disease, or diabetes were excluded. Magnetic resonance imaging (MRI) was performed to determine infarct size, area at risk (AAR) (using T2-weighted hyperintensity (T2W) and late enhancement endocardial surface area (ESA)). The primary endpoint was of 4-month final infarct size, corrected for the AAR measured in the acute phase using MRI.. After exclusion, 91 patients (age 57.4±10.1years, 76% male) completed the protocol. There were no baseline differences between groups. No difference was found in infarct size corrected for the AAR in the exenatide group compared to the placebo group (37.1±18.8 vs. 39.3±20.1%, p=0.662). There was also no difference in infarct size (18.8±13.2 vs. 18.8±11.3% of left ventricular mass, p=0.965). No major adverse cardiac events occurred during the in-hospital phase.. Exenatide did not reduce myocardial infarct size expressed as a percentage of AAR in ST elevated myocardial infarction patients successfully treated with percutaneous coronary intervention.

Topics: Aged; Double-Blind Method; Exenatide; Female; Follow-Up Studies; Glucagon-Like Peptide-1 Receptor; Humans; Male; Middle Aged; Myocardial Infarction; Peptides; Percutaneous Coronary Intervention; Prospective Studies; Treatment Outcome; Venoms

Hyperglycemia upon hospital admission in patients with ST-segment elevation myocardial infarction (STEMI) occurs frequently and is associated with adverse outcomes. It is, however, unsettled as to whether an elevated blood glucose level is the cause or consequence of increased myocardial damage. In addition, whether the cardioprotective effect of exenatide, a glucose-lowering drug, is dependent on hyperglycemia remains unknown. The objectives of this substudy were to evaluate the association between hyperglycemia and infarct size, myocardial salvage, and area at risk, and to assess the interaction between exenatide and hyperglycemia. A total of 210 STEMI patients were randomized to receive intravenous exenatide or placebo before percutaneous coronary intervention. Hyperglycemia was associated with larger area at risk and infarct size compared with patients with normoglycemia, but the salvage index and infarct size adjusting for area at risk did not differ between the groups. Treatment with exenatide resulted in increased salvage index both among patients with normoglycemia and hyperglycemia. Thus, we conclude that the association between hyperglycemia upon hospital admission and infarct size in STEMI patients is a consequence of a larger myocardial area at risk but not of a reduction in myocardial salvage. Also, cardioprotection by exenatide treatment is independent of glucose levels at hospital admission. Thus, hyperglycemia does not influence the effect of the reperfusion treatment but rather represents a surrogate marker for the severity of risk and injury to the myocardium.

Topics: Acute Disease; Aged; Cardiotonic Agents; Exenatide; Female; Heart; Humans; Hyperglycemia; Hypoglycemic Agents; Male; Middle Aged; Myocardial Infarction; Myocardium; Peptides; Risk; Severity of Illness Index; Venoms

Experimental evidence suggests that exenatide, a glucagon-like peptide 1 receptor analogue, has significant cardiovascular protective effects in various conditions. We examined whether routine use of exenatide at the time of primary percutaneous coronary intervention would reduce infarct size in patients with ST-segment-elevation myocardial infarction.. Fifty-eight patients with ST-segment-elevation myocardial infarction and thrombolysis in myocardial infarction flow 0 were enrolled in the study and randomly assigned to receive either exenatide or placebo (saline) subcutaneously. Infarct size was assessed by measuring the release of creatine kinase-MB and troponin I during 72 hours and by performing cardiac magnetic resonance imaging at 1 month after infarction. Routine and speckle tracking echocardiography was performed at initial presentation and at 3 days and 6 months after primary percutaneous coronary intervention. The exenatide and control groups had similar results with respect to ischemia time, demographic characteristics, and ejection fraction before primary percutaneous coronary intervention. The releases of creatine kinase-MB and troponin I were significantly reduced in the exenatide group. In 58 patients evaluated with cardiac magnetic resonance, the absolute mass of delayed hyperenhancement was significantly reduced in the exenatide group as compared with the control group (12.8±11.7 versus 26.4±11.6 g; P<0.01). At 6 months, the exenatide group showed a significantly lower value of E/E' with improved strain parameters. No significant adverse effects of exenatide administration were detected.. In patients with ST-segment-elevation myocardial infarction, adjunctive exenatide therapy with primary percutaneous coronary intervention was associated with reduction of infarct size and improvement of subclinical left ventricular function.

Topics: Aged; Biomarkers; Cardiotonic Agents; Chi-Square Distribution; Creatine Kinase, MB Form; Drug Administration Schedule; Echocardiography, Doppler; Exenatide; Female; Humans; Hypoglycemic Agents; Injections, Subcutaneous; Magnetic Resonance Imaging; Male; Middle Aged; Myocardial Contraction; Myocardial Infarction; Myocardium; Peptides; Percutaneous Coronary Intervention; Predictive Value of Tests; Proportional Hazards Models; Prospective Studies; Republic of Korea; Stroke Volume; Time Factors; Treatment Outcome; Troponin I; Venoms; Ventricular Function, Left

Topics: Administration, Intravenous; Aged; Exenatide; Feasibility Studies; Female; Follow-Up Studies; Glucagon-Like Peptide 1; Humans; Male; Middle Aged; Myocardial Infarction; Peptides; Percutaneous Coronary Intervention; Treatment Outcome; Venoms

Exenatide, a glucagon-like-peptide-1 analogue, increases myocardial salvage in experimental settings with coronary occlusion and subsequent reperfusion. We evaluated the cardioprotective effect of exenatide at the time of reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI).. A total of 172 patients with STEMI and Thrombolysis in Myocardial Infarction flow 0/1 were randomly assigned to exenatide or placebo (saline) intravenously. Study treatment was commenced 15 min before intervention and maintained for 6 h after the procedure. The primary endpoint was salvage index calculated from myocardial area at risk (AAR), measured in the acute phase, and final infarct size measured 90 ± 21 days after pPCI by cardiac magnetic resonance (CMR). In 105 patients evaluated with CMR, a significantly larger salvage index was found in the exenatide group than in the placebo group (0.71 ± 0.13 vs. 0.62 ± 0.16; P= 0.003). Infarct size in relation to AAR was also smaller in the exenatide group (0.30 ± 0.15 vs. 0.39 ± 0.15; P= 0.003). In a regression analysis, there was a significant correlation between the infarct size and the AAR for both treatment groups and an analysis of covariance showed that datapoints in the exenatide group lay significantly lower than for the placebo group (P= 0.011). There was a trend towards smaller absolute infarct size in the exenatide group (13 ± 9 vs. 17 ± 14 g; P= 0.11). No difference was observed in left ventricular function or 30-day clinical events. No adverse effects of exenatide were observed.. In patients with STEMI undergoing pPCI, administration of exenatide at the time of reperfusion increases myocardial salvage.

Topics: Aged; Angioplasty, Balloon, Coronary; Cardiotonic Agents; Double-Blind Method; Exenatide; Female; Humans; Male; Middle Aged; Myocardial Infarction; Myocardial Reperfusion Injury; Peptides; Venoms

Exenatide has been demonstrated to be cardioprotective as an adjunct to primary percutaneous coronary intervention in patients with ST-segment-elevation myocardial infarction (STEMI). The aim of the post hoc analysis study was to evaluate the effect of exenatide in relation to system delay, defined as time from first medical contact to first balloon.. Patients with STEMI and Thrombolysis In Myocardial Infarction flow 0/1 were randomly assigned to intravenous exenatide or placebo continuous infusion. Study treatment was commenced 15 minutes before intervention and maintained for 6 hours after the procedure. The patients were stratified according to median system delay (132 minutes). Final infarct size and myocardial area at risk were measured by cardiovascular magnetic resonance. Among patients with a system delay ≤132 minutes (n=74), treatment with exenatide resulted in a smaller infarct size (9 grams [interquartile range (IQR), 4-13] versus 13 grams [IQR, 8-24], P=0.008, corresponding to 8% [IQR, 4-12] versus 11% [IQR, 7-17] of the left ventricle, P=0.015). In a regression analysis adjusting for myocardial area at risk the data points of the exenatide group lay significantly lower than for the placebo group (P=0.006). In the patients with system delay >132 minutes (n=74) no difference was observed in infarct size expressed as grams (P=0.49) or percentage (P=0.46). There was significant interaction between system delay (less than or equal to median versus greater than median) and treatment allocation in terms of infarct size (P=0.018).. In this post hoc analysis, exenatide treatment was associated with a 30% decrease in final infarct size in patients with short system delay, whereas no cardioprotective effect in patients with long system delay was seen. However, this finding must be confirmed in larger studies.. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00835848.

Topics: Aged; Angioplasty; Chemotherapy, Adjuvant; Coronary Vessels; Disease-Free Survival; Electrocardiography; Exenatide; Female; Heart; Humans; Hypoglycemic Agents; Magnetic Resonance Imaging; Male; Middle Aged; Myocardial Infarction; Myocardium; Peptides; Radiography; Reperfusion Injury; Venoms; Warm Ischemia

The association between reperfusion delay and myocardial damage has previously been assessed by evaluation of the duration from symptom onset to invasive treatment, but results have been conflicting. System delay defined as the duration from first medical contact to first balloon dilatation is less prone to bias and is also modifiable. The purpose was to evaluate the impact of system delay on myocardial salvage index (MSI) and infarct size in patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention (PCI).. In patients with ST-elevation myocardial infarction, MSI and final infarct size were assessed using cardiovascular magnetic resonance. Myocardial area at risk was measured within 1 to 7 days, and final infarct size was measured 90 ± 21 days after intervention. Patients were grouped according to system delay (0 to 120, 121 to 180, and >180 minutes).. In 219 patients, shorter system delay was associated with a smaller infarct size (8% [interquartile range 4-12%], 10% [6-16%], and 13% [8-17%]; P < .001) and larger MSI (0.77 [interquartile range 0.66-0.86], 0.72 [0.59-0.80], and 0.68 [0.64-0.72]; P = .005) for a system delay of up to 120, 121 to 180, and >180 minutes, respectively. A short system delay as a continuous variable independently predicted a smaller infarct size (r = 0.30, P < .001) and larger MSI (r = -0.25, P < .001) in multivariable linear regression analyses. Finally, shorter system delay (0-120 minutes) was associated with improved function (P = .019) and volumes of left ventricle (P = .022).. A shorter system delay resulted in smaller infarct size, larger MSI, and improved LV function in patients treated with primary PCI. Thus, this study confirms that minimizing system delay is crucial for primary PCI-related benefits.

Topics: Cardiotonic Agents; Coronary Occlusion; Exenatide; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Myocardial Infarction; Myocardial Reperfusion; Myocardial Revascularization; Peptides; Regression Analysis; Time Factors; Venoms; Ventricular Function, Left

Myocardial infarction causes irreversible loss of cardiomyocytes and may lead to loss of ventricular function, morbidity and mortality. Infarct size is a major prognostic factor and reduction of infarct size has therefore been an important objective of strategies to improve outcomes. In experimental studies, glucagon-like peptide 1 and exenatide, a long acting glucagon-like peptide 1 receptor agonist, a novel drug introduced for the treatment of type 2 diabetes, reduced infarct size after myocardial infarction by activating pro-survival pathways and by increasing metabolic efficiency.. The EXAMI trial is a multi-center, prospective, randomized, placebo controlled trial, designed to evaluate clinical outcome of exenatide infusion on top of standard treatment, in patients with an acute myocardial infarction, successfully treated with primary percutaneous coronary intervention. A total of 108 patients will be randomized to exenatide (5 μg bolus in 30 minutes followed by continuous infusion of 20 μg/24 h for 72 h) or placebo treatment. The primary end point of the study is myocardial infarct size (measured using magnetic resonance imaging with delayed enhancement at 4 months) as a percentage of the area at risk (measured using T2 weighted images at 3-7 days).. If the current study demonstrates cardioprotective effects, exenatide may constitute a novel therapeutic option to reduce infarct size and preserve cardiac function in adjunction to reperfusion therapy in patients with acute myocardial infarction.. ClinicalTrials.gov: NCT01254123.

Topics: Acute Disease; Clinical Protocols; Exenatide; Humans; Myocardial Infarction; Peptides; Prospective Studies; Venoms

Sirt1 is a potent inhibitor of both poly(ADP-ribose) polymerases1 (PARP1) and NF-kB. This study investigated the cardioprotective effect of exendin-4 on cardiac function and remodeling in rats after an expreimentally-induced myocardial infarction (MI) and explored if this protection involves SIRT1/PARP1 axis. Rats were divided into five groups (n = 10/each): sham, sham + exendin-4 (25 nmol/kg/day i.p.), MI (induced by LAD occlusion), MI + exendin-4, and sham + exendin-4 + EX527 (5 mg/2×/week) (a SIRT1 inhibitor). All treatments were given for 6 weeks post the induction of MI. In sham-operated and MI-induced rats, exendin-4 significantly upregulated Bcl-2 levels, enhanced activity, mRNA, and levels of SIRT1, inhibited activity, mRNA, and levels of PARP1, and reduced ROS generation and PARP1 acetylation. In MI-treated rats, these effects were associated with improved cardiac architectures and LV function, reduced collagen deposition, and reduced mRNA and total levels of TNF-α and IL-6, as well as, the activation of NF-κB p65. In addition, exendin-4 inhibited the interaction of PARP1 with p300, TGF-β1, Smad3, and NF-κB p65 and signficantly reduced mRNA and protein levels of collagen I/III and protein levels of MMP2/9. In conclusion, exendin-4 is a potent cardioprotective agent that prevents post-MI inflammation and cardiac remodeling by activating SIRT1-induced inhibition of PARP1.

Topics: Acetylation; Animals; Anti-Inflammatory Agents; Apoptosis; Disease Models, Animal; Exenatide; Fibrosis; Glucagon-Like Peptide-1 Receptor; Incretins; Male; Myocardial Infarction; Myocytes, Cardiac; NF-kappa B; Poly (ADP-Ribose) Polymerase-1; Rats, Wistar; Signal Transduction; Sirtuin 1; Ventricular Function, Left; Ventricular Remodeling

Topics: Acetates; Animals; Exenatide; Gallium Radioisotopes; Glucagon-Like Peptide-1 Receptor; Heterocyclic Compounds, 1-Ring; Humans; Laboratories; Lizards; Myocardial Infarction; Positron-Emission Tomography; Tomography, X-Ray Computed

Myocardial infarction (MI) is one of the main causes of morbidity and mortality in diabetic patients. The antidiabetic glucagon-like polypeptide-1 receptor (GLP-1R) agonists, such as exenatide, proved to confer cardioprotection; however, their exact mechanisms are not fully elucidated. Although the cardioprotective effect of α-estrogen receptor (ERα) activation is well established, its involvement in exenatide-induced cardioprotection has never been investigated. Moreover, modulation of insulin-like growth factor-1/2 (IGF-1/IGF-2) system by exenatide, and the consequent effect on cardiomyocyte apoptosis, is yet to be established. Current study aimed to investigate the cardioprotective potential of exenatide versus the standard cardioprotective agent, 17β-estradiol, against isoprenaline (ISO)-induced MI in rats. MI-insulted group showed electrocardiographic abnormalities, elevated serum cardiac markers, higher serum IGF-2 level along with histopathological abnormalities. Treatment with exenatide and/or 17β-estradiol, commenced 8 weeks before ISO insult, ameliorated these anomalies with maximum cardioprotection achieved with combined treatment. This was associated with upregulation of both ERα and IGF-1R, and downregulation of IGF-2R in left ventricles. Inhibition of ERs in Langendorff preparations confirmed their involvement in mediating exenatide-induced cardioprotective effect. Current study showed that the GLP-1R agonist exenatide exerted cardioprotection associated with upregulation of ERα and modulation of IGF-1/IGF-2 signaling in favor of antiapoptosis.

Topics: Animals; Apoptosis; Cytoprotection; Disease Models, Animal; Estradiol; Estrogen Receptor alpha; Exenatide; Glucagon-Like Peptide-1 Receptor; Heart Rate; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Isolated Heart Preparation; Isoproterenol; Male; Myocardial Infarction; Myocardium; Rats, Wistar; Receptor, IGF Type 1; Signal Transduction; Ventricular Function, Left

Exenatide and cyclosporine A have been shown to moderately protect against myocardial reperfusion injury leading to reduction of infarct size in patients. Our objective was to investigate whether the combined treatment with exenatide (glucagon-like peptide 1 receptor agonist) and cyclosporine A or parstatin 1-26 (inhibitors of mitochondrial permeability transition pore and/or inflammation) is more beneficial than either agent alone. Rabbits underwent 40 minutes of ischemia and 120 minutes of reperfusion. Intravenous bolus administration of exenatide or cyclosporine A, 10 minutes before reperfusion, reduced infarct size by 38% (P < 0.05) and 40% (P < 0.05), and cardiac troponin I (cTnI) plasma levels by 48% (P < 0.05) and 36% (P < 0.05), respectively, compared with control. The combined administration of both agents resulted in an additive decrease of infarct size by 55% (P < 0.05) and cTnI release by 61% (P < 0.05). Also, combined treatment of exenatide and parstatin 1-26 enhanced infarct size reduction (62%, P < 0.05), compared with monotherapies (41% for parstatin 1-26, P < 0.05; 43% for exenatide, P < 0.05). In contrast, the combined administration of parstatin 1-26 and cyclosporine A canceled out the cardioprotective effects observed by monotherapies. These results suggest that, for the therapy of myocardial reperfusion injury the combined administration of exenatide and cyclosporine A or parstatin 1-26 is more effective than monotherapies and may provide advantageous clinical outcome.

Topics: Animals; Cyclosporine; Disease Models, Animal; Drug Therapy, Combination; Exenatide; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Peptide Fragments; Peptides; Rabbits; Receptor, PAR-1; Venoms

We have demonstrated that glucagon like peptide-1 (GLP-1) protects the heart against ischemic injury. However, the physiological mechanism by which GLP-1 receptor (GLP-1R) initiates cardioprotection remains to be determined. The objective of this study is to elucidate the functional roles of MAPK kinase 3 (MKK3) and Akt-1 in mediating exendin-4-elicited protection in the infarcted hearts. Adult mouse myocardial infarction (MI) was created by ligation of the left descending artery. Wild-type, MKK3(-/-), Akt-1(-/-), and Akt-1(-/-);MKK3(-/-) mice were divided into one of several groups: 1) sham: animals underwent thoracotomy without ligation; 2) MI: animals underwent MI and received a daily dose of intraperitoneal injection of vehicle (saline); 3) MI + exendin-4: infarcted mice received daily injections of exendin-4, a GLP-1R agonist (0.1 mg/kg, ip). Echocardiographic measurements indicate that exendin-4 treatment resulted in the preservation of ventricular function and increases in the survival rate, but these effects were diminished in MKK3(-/-), Akt-1(-/-), and Akt-1(-/-);MKK3(-/-) mice. Exendin-4 treatments suppressed cardiac hypotrophy and reduced scar size and cardiac interstitial fibrosis, respectively, but these beneficial effects were lost in genetic elimination of MKK3, Akt-1, or Akt-1(-/-);MKK3(-/-) mice. GLP-1R stimulation stimulated angiogenic responses, which were also mitigated by deletion of MKK3 and Akt-1. Exendin-4 treatment increased phosphorylation of MKK3, p38, and Akt-1 at Ser129 but decreased levels of active caspase-3 and cleaved poly (ADP-ribose) polymerase; these proteins were diminished in MKK3(-/-), Akt-1(-/-), and Akt-1(-/-);MKK3(-/-) mice. These results reveal that exendin-4 treatment improves cardiac function, attenuates cardiac remodeling, and promotes angiogenesis in the infarcted myocardium through MKK3 and Akt-1 pathway.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Cardiomegaly; Cardiotonic Agents; Disease Models, Animal; Enzyme Activation; Exenatide; Fibrosis; MAP Kinase Kinase 3; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Myocardium; Neovascularization, Physiologic; Peptides; Phosphorylation; Proto-Oncogene Proteins c-akt; Signal Transduction; Stroke Volume; Time Factors; Venoms; Ventricular Function, Left; Ventricular Remodeling

Despite its high prevalence among patients suffering myocardial infarction, the significance of left ventricle hypertrophy for infarct size is not known. We asked whether infarct size might be increased by this condition, and whether any such increase might be associated with an increased mitochondrial damage following coronary occlusion.. Occlusion of the left descending artery in isolated, perfused hearts of SHR-SP (spontaneously hypertensive rat stroke-prone) (left ventricular hypertrophy) or Wistar-Kyoto (WKY) (control) rats was used, followed by reperfusion with or without exendin-4 (Exe-4), a glucagon-like peptide-1 receptor agonist. Infarct size relative to area-at-risk was determined. Separately, mitochondria were isolated after global ischemia. Activities of complexes III and IV and amounts of selected complex subunits and cytochromes a, b, c, and c1 were determined.. Infarct size (ischemia 35  min and 120  min reperfusion) was 65.8% (±3.3%) and 37.1% (±3.4%) in the SHR-SP and WKY hearts, respectively (P < 0.05). Exe-4 significantly decreased infarct size and hypercontracture in WKY, but not in SHR-SP, hearts. After ischemia 15  min in SHR-SP hearts, Exe-4 reduced the infarct (26.6%, ±3.8% to 9.3% ± 1.5%; P < 0.05). Mitochondria from postischemic SHR-SP hearts showed a reduction of complex III (368.1 ± 37.5 to 175.8 ± 23.0  nmoles/min × mg; P < 0.05) and complex IV (14.4 ± 0.22 to 5.8 ± 0.8 1/s × mg; P < 0.05) activities and decreased amounts of cytochromes a, b, and c.. Hearts from hypertensive (SHR-SP) rats with left ventricle hypertrophy appeared more vulnerable to ischemia-reperfusion injury, as supported by a more profound infarct development and an earlier loss of postconditioning by Exe-4. Mitochondrial complexes III and IV were identified among possible loci of this increased, hypertrophy-associated vulnerability.

Topics: Animals; Cytochromes; Electron Transport Complex III; Electron Transport Complex IV; Exenatide; Heart; Hypertension; Hypertrophy, Left Ventricular; Incretins; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Peptides; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Severity of Illness Index; Venoms

Glucagon-like peptide-1 (GLP-1) therapies are routinely used for glycaemic control in diabetes and their emerging cardiovascular actions have been a major recent research focus. In addition to GLP-1 receptor activation, the metabolically-inactive breakdown product, GLP-1(9-36)amide, also appears to exert notable cardiovascular effects, including protection against acute cardiac ischaemia. Here, we specifically studied the influence of GLP-1(9-36)amide on chronic post-myocardial infarction (MI) remodelling, which is a major driver of heart failure progression.. Adult female C57BL/6 J mice were subjected to permanent coronary artery ligation or sham surgery prior to continuous infusion with GLP-1(9-36)amide or vehicle control for 4 weeks.. Infarct size was similar between groups with no effect of GLP-1(9-36)amide on MI-induced cardiac hypertrophy, although modest reduction of in vitro phenylephrine-induced H9c2 cardiomyoblast hypertrophy was observed. Whilst echocardiographic systolic dysfunction post-MI remained unchanged, diastolic dysfunction (decreased mitral valve E/A ratio, increased E wave deceleration rate) was improved by GLP-1(9-36)amide treatment. This was associated with modulation of genes related to extracellular matrix turnover (MMP-2, MMP-9, TIMP-2), although interstitial fibrosis and pro-fibrotic gene expression were unaltered by GLP-1(9-36)amide. Cardiac macrophage infiltration was also reduced by GLP-1(9-36)amide together with pro-inflammatory cytokine expression (IL-1β, IL-6, MCP-1), whilst in vitro studies using RAW264.7 macrophages revealed global potentiation of basal pro-inflammatory and tissue protective cytokines (e.g. IL-1β, TNF-α, IL-10, Fizz1) in the presence of GLP-1(9-36)amide versus exendin-4.. These data suggest that GLP-1(9-36)amide confers selective protection against post-MI remodelling via preferential preservation of diastolic function, most likely due to modulation of infiltrating macrophages, indicating that this often overlooked GLP-1 breakdown product may exert significant actions in this setting which should be considered in the context of GLP-1 therapy in patients with cardiovascular disease.

Topics: Animals; Cardiotonic Agents; Exenatide; Female; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Mice; Mice, Inbred C57BL; Myocardial Infarction; Myocardium; Peptides; Tissue Inhibitor of Metalloproteinase-2; Tumor Necrosis Factor-alpha; Venoms; Ventricular Function, Left; Ventricular Remodeling

We aimed to assess the effect of exenatide treatment as an adjunct to primary percutaneous coronary intervention (PCI) on long-term clinical outcome.. We performed a post hoc analysis in 334 patients with a first STEMI included in a previous study randomised to exenatide (n=175) or placebo (n=159) as an adjunct to primary PCI. The primary endpoint was a composite of all-cause mortality and admission for heart failure during a median follow-up of 5.2 years (interquartile range: 5.0-5.5). Secondary endpoints were all-cause mortality and admission for heart failure, individually. The primary composite endpoint occurred in 24% in the exenatide group versus 27% in the placebo group, p=0.44 (HR 0.80, p=0.35). Admission for heart failure was lower in the exenatide (11%) compared to the placebo group (20%) (HR 0.53, p=0.042). All-cause mortality occurred in 14% in the exenatide group versus 9% in the placebo group (HR 1.45, p=0.20).. In this post hoc analysis of patients with a STEMI, treatment with exenatide at the time of primary PCI did not reduce the primary composite endpoint or the secondary endpoint of all-cause -mortality. However, exenatide treatment reduced the incidence of admission for heart failure.

Topics: Adult; Aged; Aged, 80 and over; Electrocardiography; Exenatide; Female; Heart Failure; Humans; Male; Middle Aged; Myocardial Infarction; Peptides; Percutaneous Coronary Intervention; Platelet Aggregation Inhibitors; Prognosis; Treatment Outcome; Venoms

Exercise capacity is reduced in heart failure (HF) patients, due mostly to skeletal muscle abnormalities including impaired energy metabolism, mitochondrial dysfunction, fibre type transition, and atrophy. Glucagon-like peptide-1 (GLP-1) has been shown to improve exercise capacity in HF patients. We investigated the effects of the administration of a dipeptidyl peptidase (DPP)-4 inhibitor on the exercise capacity and skeletal muscle abnormalities in an HF mouse model after myocardial infarction (MI).. MI was created in male C57BL/6J mice by ligating the left coronary artery, and a sham operation was performed in other mice. The mice were then divided into two groups according to the treatment with or without a DPP-4 inhibitor, MK-0626 [1 mg/kg body weight (BW)/day] provided in the diet. Four weeks later, the exercise capacity evaluated by treadmill test was revealed to be limited in the MI mice, and it was ameliorated in the MI + MK-0626 group without affecting the infarct size or cardiac function. The citrate synthase activity, mitochondrial oxidative phosphorylation capacity, supercomplex formation, and their quantity were reduced in the skeletal muscle from the MI mice, and these decreases were normalized in the MI + MK-0626 group, in association with the improvement of mitochondrial biogenesis. Immunohistochemical staining also revealed that a shift toward the fast-twitch fibre type in the MI mice was also reversed by MK-0626. Favourable effects of MK-0626 were significantly inhibited by treatment of GLP-1 antagonist, Exendin-(9-39) (150 pmol/kg BW/min, subcutaneous osmotic pumps) in MI + MK-0626 mice. Similarly, exercise capacity and mitochondrial function were significantly improved by treatment of GLP-1 agonist, Exendin-4 (1 nmol/kg/BW/h, subcutaneous osmotic pumps).. A DPP-4 inhibitor may be a novel therapeutic agent against the exercise intolerance seen in HF patients by improving the mitochondrial biogenesis in their skeletal muscle.

Topics: Animals; Dipeptidyl-Peptidase IV Inhibitors; Disease Models, Animal; Exenatide; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Male; Mice, Inbred C57BL; Mitochondria; Muscle, Skeletal; Myocardial Infarction; Organelle Biogenesis; Peptides; Triazoles; Venoms

Although the nature of the humoral factor which mediates cardioprotection established by remote ischaemic conditioning (RIc) remains unknown, parasympathetic (vagal) mechanisms appear to play a critical role. As the production and release of many gut hormones is modulated by the vagus nerve, here we tested the hypothesis that RIc cardioprotection is mediated by the actions of glucagon-like peptide-1 (GLP-1).. A rat model of myocardial infarction (coronary artery occlusion followed by reperfusion) was used. Remote ischaemic pre- (RIPre) or perconditioning (RIPer) was induced by 15 min occlusion of femoral arteries applied prior to or during the myocardial ischaemia. The degree of RIPre and RIPer cardioprotection was determined in conditions of cervical or subdiaphragmatic vagotomy, or following blockade of GLP-1 receptors (GLP-1R) using specific antagonist Exendin(9-39). Phosphorylation of PI3K/AKT and STAT3 was assessed. RIPre and RIPer reduced infarct size by ∼50%. In conditions of bilateral cervical or subdiaphragmatic vagotomy RIPer failed to establish cardioprotection. GLP-1R blockade abolished cardioprotection induced by either RIPre or RIPer. Exendin(9-39) also prevented RIPre-induced AKT phosphorylation. Cardioprotection induced by GLP-1R agonist Exendin-4 was preserved following cervical vagotomy, but was abolished in conditions of M3 muscarinic receptor blockade.. These data strongly suggest that GLP-1 functions as a humoral factor of remote ischaemic conditioning cardioprotection. This phenomenon requires intact vagal innervation of the visceral organs and recruitment of GLP-1R-mediated signalling. Cardioprotection induced by GLP-1R activation is mediated by a mechanism involving M3 muscarinic receptors.

Topics: Animals; Disease Models, Animal; Exenatide; Femoral Artery; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Hormone Antagonists; Ischemic Preconditioning; Ligation; Male; Muscarinic Antagonists; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Peptide Fragments; Peptides; Phosphatidylinositol 3-Kinase; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats, Sprague-Dawley; Receptor, Muscarinic M3; Signal Transduction; STAT3 Transcription Factor; Vagotomy; Vagus Nerve; Venoms

A Site-specifically PEGylated exendin-4 (denoted as PEG-Ex4) is an exendin-4 (denoted as Ex4) analog we developed by site-specific PEGylation of exendin-4 with a high molecular weight trimeric poly(ethylene glycol) (tPEG). It has been shown to possess prolonged half-life in vivo with similar receptor binding affinity compared to unmodified exendin-4 by our previous work. This study is sought to test whether PEG-Ex4 is suitable for treating myocardial infarction (MI). In the MI model, PEG-Ex4 was administered every 3 days while equivalent amount of Ex4 was administered every 3 days or twice daily. Animal survival rate, heart function, remodeling and neoangiogenesis were evaluated and compared. Tube formation was examined in endothelial cells. In addition, Western blotting and histology were performed to determine the markers of cardiac hypertrophy and angiogenesis and to explore the possible molecular mechanism involved. PEG-Ex4 and Ex4 showed comparable binding affinity to GLP-1 receptor. In MI mice, PEG-Ex4 given at 3 days interval achieved similar extent of protection as Ex4 given twice daily, while Ex4 given at 3 days interval failed to produce protection. PEG-Ex4 elevated endothelial tube formation in vitro and capillary density in the border area of MI. PEG-Ex4 increased Akt activity and VEGF production in a GLP-1R dependent manner in endothelial cells and antagonism of GLP-1R, Akt or VEGF abolished the protection of PEG-Ex4 in the MI model. PEG-Ex4 is a potent long-acting GLP-1 receptor agonist for the treatment of chronic heart disease. Its protection might be attributed to enhanced angiogenesis mediated by the activation of Akt and VEGF.

Topics: Aminophylline; Animals; Atropine; Blotting, Western; Cardiovascular Agents; Disease Models, Animal; Drug Combinations; Exenatide; Glucagon-Like Peptide 1; Heart; Heart Function Tests; Histocytochemistry; Male; Mice, Inbred C57BL; Myocardial Infarction; Myocardium; Neovascularization, Physiologic; Nitroglycerin; Papaverine; Peptides; Phenobarbital; Survival Analysis; Treatment Outcome; Venoms

Glucagon-like peptide-1 (GLP-1) is an insulin-releasing hormone clinically exploited for glycaemic control in diabetes, which also confers acute cardioprotection and benefits in experimental/clinical heart failure. We specifically investigated the role of the GLP-1 mimetic, exendin-4, in post-myocardial infarction (MI) remodelling, which is a key contributor to heart failure. Adult female normoglycaemic mice underwent coronary artery ligation/sham surgery prior to infusion with exendin-4/vehicle for 4 weeks. Metabolic parameters and infarct sizes were comparable between groups. Exendin-4 protected against cardiac dysfunction and chamber dilatation post-MI and improved survival. Furthermore, exendin-4 modestly decreased cardiomyocyte hypertrophy/apoptosis but markedly attenuated interstitial fibrosis and myocardial inflammation post-MI. This was associated with altered extracellular matrix (procollagen IαI/IIIαI, connective tissue growth factor, fibronectin, TGF-β3) and inflammatory (IL-10, IL-1β, IL-6) gene expression in exendin-4-treated mice, together with modulation of both Akt/GSK-3β and Smad2/3 signalling. Exendin-4 also altered macrophage response gene expression in the absence of direct actions on cardiac fibroblast differentiation, suggesting cardioprotective effects occurring secondary to modulation of inflammation. Our findings indicate that exendin-4 protects against post-MI remodelling via preferential actions on inflammation and the extracellular matrix independently of its established actions on glycaemic control, thereby suggesting that selective targeting of GLP-1 signalling may be required to realise its clear therapeutic potential for post-MI heart failure.

Topics: Animals; Blotting, Western; Disease Models, Animal; Exenatide; Extracellular Matrix; Female; Immunohistochemistry; In Situ Nick-End Labeling; Inflammation; Mice; Mice, Inbred C57BL; Myocardial Infarction; Peptides; Rats; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Venoms; Ventricular Remodeling

To investigate the cardioprotective effects of isoflurane and exendin-4 against myocardial ischemia/reperfusion injury and the signaling pathways through which these effects are mediated.. For infarct size measurements, anesthetized mice were subjected to 30 min of coronary artery occlusion followed by 2 h of reperfusion. Wild-type or caveolin-3 knockout mice received isoflurane, exendin-4, or isoflurane with exendin-4 before ischemia index determination. Caveolin-3 expression in the heart was measured by immunoblotting.. Myocardial infarct size was smaller in the isoflurane- [1.0 minimum alveolar concentration (MAC)] or exendin-4- (30 ng/kg i.v.) treated groups than the controls. Infarct size was not affected by isoflurane at 0.5 MAC or 3 ng/kg i.v. exendin-4, but the combination of these treatments reduced infarct size. Pharmacological preconditioning (isoflurane at 1.0 MAC, 30 ng/kg i.v. exendin-4, or isoflurane at 0.5 MAC with 3 ng/kg i.v. exendin-4) increased caveolin-3 protein expression in the heart after infarct induction. The cardioprotective effects of isoflurane, exendin-4, and isoflurane with exendin-4 were abolished in caveolin-3 knockout mice.. The combination of isoflurane and exendin-4 reduced infarct size, but it was not more effective than either agent alone, and the cardioprotective effects of these agents are mediated by caveolin-3 expression.

Topics: Anesthetics, Inhalation; Animals; Caveolin 3; Drug Therapy, Combination; Exenatide; Glucagon-Like Peptide-1 Receptor; Ischemic Preconditioning, Myocardial; Isoflurane; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Myocardial Reperfusion Injury; Peptides; Venoms

Remote ischaemic conditioning (RIC) has been shown to reduce myocardial infarct size in patients. Our objective was to investigate whether the combination of RIC with either exenatide or glucose-insulin-potassium (GIK) is more effective than RIC alone.. Pigs were submitted to 40 min of coronary occlusion followed by reperfusion, and received (i) no treatment, (ii) one of the following treatments: RIC (5 min ischemia/5 min reperfusion × 4), GIK, or exenatide (at doses reducing infarct size in clinical trials), or (iii) a combination of two of these treatments (RIC + GIK or RIC + exenatide). After 5 min of reperfusion (n = 4/group), prominent phosphorylation of Akt and endothelial nitric oxide synthase (eNOS) was observed, both in control and reperfused myocardium, in animals receiving GIK, and mitochondria from these hearts showed reduced ADP-stimulated respiration. (1)H NMR-based metabonomics disclosed a shift towards increased glycolysis in GIK and exenatide groups. In contrast, oxidative stress (myocardial nitrotyrosine levels) and eNOS uncoupling were significantly reduced only by RIC. In additional experiments (n = 7-10/group), ANOVA demonstrated a significant effect of the number of treatments after 2 h of reperfusion on infarct size (triphenyltetrazolium, % of the area at risk; 59.21 ± 3.34, 36.64 ± 3.03, and 21.04 ± 2.38% for none, one, and two treatments, respectively), and significant differences between one and two treatments (P = 0.004) but not among individual treatments or between RIC + GIK and RIC + exenatide.. GIK and exenatide activate cardioprotective pathways different from those of RIC, and have additive effects with RIC on infarct size reduction in pigs.

Topics: Aging; Animals; Exenatide; Glucose; Insulin; Ischemia; Myocardial Infarction; Myocardial Reperfusion; Myocardial Reperfusion Injury; Peptides; Potassium; Swine; Venoms

The poor survival of cells in ischaemic myocardium is a major obstacle for stem cell therapy. Exendin-4 holds the potential of cardioprotective effect based on its pleiotropic activity. This study investigated whether Exendin-4 in conjunction with adipose-derived stem cells (ADSCs) could improve the stem cell survival and contribute to myocardial repairs after infarction. Myocardial infarction (MI) was induced by the left anterior descending artery ligation in adult male Sprague-Dawley rats. ADSCs carrying double-fusion reporter gene [firefly luciferase and monomeric red fluorescent protein (fluc-mRFP)] were quickly injected into border zone of MI in rats treated with or without Exendin-4. Exendin-4 enhanced the survival of transplanted ADSCs, as demonstrated by the longitudinal in vivo bioluminescence imaging. Moreover, ADSCs adjuvant with Exendin-4 decreased oxidative stress, apoptosis and fibrosis. They also improved myocardial viability and cardiac function and increased the differentiation rates of ADSCs into cardiomyocytes and vascular smooth muscle cells in vivo. Then, ADSCs were exposed to hydrogen peroxide/serum deprivation (H(2)O(2)/SD) to mimic the ischaemic environment in vitro. Results showed that Exendin-4 decreased the apoptosis and enhanced the paracrine effect of ADSCs. In addition, Exendin-4 activated signal transducers and activators of transcription 3 (STAT3) through the phosphorylation of Akt and ERK1/2. Furthermore, Exendin-4 increased the anti-apoptotic protein Bcl-2, but decreased the pro-apoptotic protein Bax of ADSCs. In conclusion, Exendin-4 could improve the survival and therapeutic efficacy of transplanted ADSCs through STAT3 activation via the phosphorylation of Akt and ERK1/2. This study suggests the potential application of Exendin-4 for stem cell-based heart regeneration.

Topics: Adipose Tissue; Adjuvants, Immunologic; Animals; Apoptosis; Blotting, Western; Cell Proliferation; Cells, Cultured; Chemotherapy, Adjuvant; Exenatide; Fluorescent Antibody Technique; Heart; Hypoglycemic Agents; Male; Myocardial Infarction; Peptides; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; STAT3 Transcription Factor; Stem Cells; Venoms; Xenograft Model Antitumor Assays

Reactive oxygen species (ROS), which were largely generated after myocardial ischemia, severely impaired the adhesion and survival of transplanted stem cells. In this study, we aimed to determine whether Exendin-4 pretreatment could improve the adhesion and therapeutic efficacy of transplanted adipose derived stem cells (ADSCs) in ischemic myocardium. In vitro, H2O2 was used to provide ROS environments, in which ADSCs pretreated with Exendin-4 were incubated. ADSCs without pretreatment were used as control. Then, cell adhesion and viability were analyzed with time. Compared with control ADSCs, Exendin-4 treatment significantly increased the adhesion of ADSCs in ROS environment, while reduced intracellular ROS and cell injury as determined by dihydroethidium (DHE) staining live/Dead staining, lactate dehydrogenase-release assay and MTT assay. Western Blotting demonstrated that ROS significantly decreased the expression of adhesion-related integrins and integrin-related focal adhesion proteins, which were significantly reversed by Exendin-4 pretreatment and followed by decreases in caspase-3, indicating that Exendin-4 may facilitate cell survival through enhanced adhesion. In vivo, myocardial infarction (MI) was induced by the left anterior descending artery ligation in SD rats. Autologous ADSCs with or without Exendin-4 pretreatment were injected into the border area of infarcted hearts, respectively. Multi-techniques were used to assess the beneficial effects after transplantation. Longitudinal bioluminescence imaging and histological staining revealed that Exendin-4 pretreatment enhanced the survival and differentiation of engrafted ADSCs in ischemic myocardium, accompanied with significant benefits in cardiac function, matrix remodeling, and angiogenesis compared with non-pretreated ADSCs 4 weeks post-transplantation. In conclusion, transplantation of Exendin-4 pretreated ADSCs significantly improved cardiac performance and can be an innovative approach in the clinical perspective.

Topics: Adipose Tissue; Animals; Apoptosis; Cell Adhesion; Cell Differentiation; Cell Proliferation; Cell Survival; Exenatide; Heart Function Tests; Hydrogen Peroxide; Integrins; Male; Myocardial Infarction; Neovascularization, Physiologic; Oxidative Stress; Peptides; Rats, Sprague-Dawley; Stem Cell Transplantation; Stem Cells; Ultrasonography; Venoms

Topics: Exenatide; Female; Humans; Hyperglycemia; Hypoglycemic Agents; Male; Myocardial Infarction; Myocardium; Peptides; Venoms

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.

Topics: Animals; Antioxidants; Apoptosis; Cardiotonic Agents; Cell Line; Cell Survival; Disease Models, Animal; Exenatide; Glucagon-Like Peptide-1 Receptor; Heart Ventricles; Hypertrophy, Left Ventricular; Kaplan-Meier Estimate; Male; Mice, Inbred ICR; Mitochondria, Heart; Molecular Targeted Therapy; Myoblasts, Cardiac; Myocardial Infarction; Oxidative Stress; Peptides; Rats; Receptors, Glucagon; Ultrasonography; Venoms; Ventricular Dysfunction, Left; Ventricular Remodeling

Drugs are designed for therapy, but medication-related adverse events are common, and risk/benefit analysis is critical for determining clinical use. Rosiglitazone, an efficacious antidiabetic drug, is associated with increased myocardial infarctions (MIs), thus limiting its usage. Because diabetic patients are often prescribed multiple drugs, we searched for usage of a second drug ("drug B") in the Food and Drug Administration's Adverse Event Reporting System (FAERS) that could mitigate the risk of rosiglitazone ("drug A")-associated MI. In FAERS, rosiglitazone usage is associated with increased occurrence of MI, but its combination with exenatide significantly reduces rosiglitazone-associated MI. Clinical data from the Mount Sinai Data Warehouse support the observations from FAERS. Analysis for confounding factors using logistic regression showed that they were not responsible for the observed effect. Using cell biological networks, we predicted that the mitigating effect of exenatide on rosiglitazone-associated MI could occur through clotting regulation. Data we obtained from the db/db mouse model agreed with the network prediction. To determine whether polypharmacology could generally be a basis for adverse event mitigation, we analyzed the FAERS database for other drug combinations wherein drug B reduced serious adverse events reported with drug A usage such as anaphylactic shock and suicidality. This analysis revealed 19,133 combinations that could be further studied. We conclude that this type of crowdsourced approach of using databases like FAERS can help to identify drugs that could potentially be repurposed for mitigation of serious adverse events.

Topics: Adverse Drug Reaction Reporting Systems; Animals; Blood Coagulation; Confounding Factors, Epidemiologic; Databases as Topic; Diabetes Mellitus, Experimental; Drug Combinations; Drug Interactions; Drug-Related Side Effects and Adverse Reactions; Exenatide; Heart Function Tests; Humans; Mice; Myocardial Infarction; Peptides; Plasminogen Activator Inhibitor 1; Rosiglitazone; Systems Biology; Thiazolidinediones; Thrombelastography; Ultrasonography; United States; United States Food and Drug Administration; Venoms

Glucagon-like peptide-1 (GLP-1) and its mimetics reduce infarct size in the setting of acute myocardial ischemia/reperfusion (I/R) injury. However, the short serum half-life of GLP-1 and its mimetics may limit their therapeutic use in acute myocardial ischemia. Domain antibodies to serum albumin (AlbudAbs) have been developed to extend the serum half-life of short lived therapeutic proteins, peptides and small molecules. In this study, we compared the effect of a long acting GLP-1 agonist, DPP-IV resistant GLP-1 (7-36, A8G) fused to an AlbudAb (GAlbudAb), with the effect of the GLP-1 mimetic, exendin-4 (short half-life GLP-1 agonist) on infarct size following acute myocardial I/R injury.. Male Sprague-Dawley rats (8-week-old) were treated with vehicle, GAlbudAb or exendin-4. Myocardial ischemia was induced 2 h following the final dose for GAlbudAb and 30 min post the final dose for exendin-4. In a subgroup of animals, the final dose of exendin-4 was administered (1 μg/kg, SC, bid for 2 days) 6 h prior to myocardial ischemia when plasma exendin-4 was at its minimum concentration (C(min)). Myocardial infarct size, area at risk and cardiac function were determined 24 h after myocardial I/R injury.. GAlbudAb and exendin-4 significantly reduced myocardial infarct size by 28% and 23% respectively, compared to vehicle (both p < 0.01 vs. vehicle) after I/R injury. Moreover, both GAlbudAb and exendin-4 markedly improved post-ischemic cardiac contractile function. Body weight loss and reduced food intake consistent with the activation of GLP-1 receptors was observed in all treatment groups. However, exendin-4 failed to reduce infarct size when administered 6 h prior to myocardial ischemia, suggesting continuous activation of the GLP-1 receptors is needed for cardioprotection.. Cardioprotection provided by GAlbudAb, a long acting GLP-1 mimetic, following myocardial I/R injury was comparable in magnitude, but more sustained in duration than that produced by short-acting exendin-4. Very low plasma concentrations of exendin-4 failed to protect the heart from myocardial I/R injury, suggesting that sustained GLP-1 receptor activation plays an important role in providing cardioprotection in the setting of acute myocardial I/R injury. Long-acting GLP-1 agonists such as GAlbudAb may warrant additional evaluation as novel therapeutic agents to reduce myocardial I/R injury during acute coronary syndrome.

Topics: Animals; Cardiotonic Agents; Disease Models, Animal; Exenatide; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Immunoconjugates; Injections, Subcutaneous; Male; Myocardial Contraction; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Peptide Fragments; Peptides; Rats; Rats, Sprague-Dawley; Receptors, Glucagon; Serum Albumin; Single-Domain Antibodies; Venoms; Ventricular Function, Left

High mobility group box 1 protein (HMGB1) plays an important role in myocardial ischemia and reperfusion (I/R) injury. Exendin-4 (Ex-4), glucagon-like peptide-1 receptor agonist, has been reported to attenuate myocardial I/R injury. This study was to investigate the potential mechanism by which Ex-4 attenuates myocardial I/R injury in rats.. Anesthetized male rats were once treated with Ex-4 (5 μg/kg, i.v.) 1 h before ischemiain the absence and/or presence of exendin (9-39) (an antagonist for glucagon-like peptide-1 receptor, 5 μg/kg, i.v.), and then subjected to ischemia for 30 min followed by reperfusion for 4 h. Lactate dehydrogenase (LDH), creatine kinase (CK), malondialdehyde (MDA), superoxide dismutase (SOD) activity and infarct size were measured. HMGB1 expression was assessed by immunoblotting.. The results showed that pretreatment of Ex-4 could significantly decrease the infarct size and the levels of LDH and CK after 4 h reperfusion (all p < 0.05). Ex-4 could also significantly inhibit the increase of the MDA level, the decrease of the SOD level (both p < 0.05). Meanwhile, Ex-4 could significantly inhibit HMGB1 expression induced by I/R. Administration of exendin (9-39) could abolish the protective effect of Ex-4 (all p < 0.05).. The present study suggested that Ex-4 could attenuate myocardial I/R injury which may be associated with inhibiting HMGB1 expression.

Topics: Animals; Creatine Kinase; Cytoprotection; Disease Models, Animal; Down-Regulation; Exenatide; Glucagon-Like Peptide-1 Receptor; HMGB1 Protein; L-Lactate Dehydrogenase; Male; Malondialdehyde; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Peptide Fragments; Peptides; Rats; Rats, Sprague-Dawley; Receptors, Glucagon; Superoxide Dismutase; Time Factors; Venoms

Glucagon-like peptide (GLP)-1 receptor activation increases intracellular cAMP with downstream activation of PKA. Cilostazol (CIL), a phosphodiesterase-3 inhibitor, prevents cAMP degradation. We assessed whether CIL amplifies the exenatide (EX)-induced increase in myocardial cAMP levels and PKA activity and augments the infarct size (IS)-limiting effects of EX in db/db mice. Mice fed a Western diet received oral CIL (10 mg/kg) or vehicle by oral gavage 24 h before surgery. One hour before surgery, mice received EX (1 μg/kg sc) or vehicle. Additional mice received H-89, a PKA inhibitor, alone or with CIL + EX. Mice underwent 30 min of coronary artery occlusion and 24 h of reperfusion. Both EX and CIL increased myocardial cAMP levels and PKA activity. Levels were significantly higher in the EX + CIL group. Both EX and CIL reduced IS. IS was the smallest in the CIL + EX group. H-89 completely blocked the IS-limiting effects of EX + CIL. EX + CIL decreased phosphatase and tensin homolog on chromosome 10 upregulation and increased Akt and ERK1/2 phosphorylation after ischemia-reperfusion. These effects were blocked by H-89. In conclusion, EX and CIL have additive effects on IS limitation in diabetic mice. The additive effects are related to cAMP-induced PKA activation, as H-89 blocked the protective effect of CIL + EX.

Topics: Animals; Blood Glucose; Blotting, Western; Cholesterol; Cilostazol; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Diabetes Mellitus, Type 2; Disease Models, Animal; Enzyme Activation; Exenatide; Glucagon-Like Peptide-1 Receptor; Glycated Hemoglobin; Hypoglycemic Agents; Isoquinolines; Lipoxins; Male; Mice; Myocardial Infarction; Myocardium; Peptides; Phosphodiesterase 3 Inhibitors; Phosphorylation; Protein Kinase Inhibitors; PTEN Phosphohydrolase; Receptors, Glucagon; Signal Transduction; Sulfonamides; Tetrazoles; Triglycerides; Up-Regulation; Venoms

Topics: Cardiotonic Agents; Exenatide; Female; Humans; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Peptides; Venoms

This study sought to examine whether exenatide is capable of reducing myocardial infarct size.. Exenatide is a glucagon-like peptide (GLP)-1 analogue with insulinotropic and insulinomimetic properties. Because insulin and GLP-1 have been described as reducing apoptosis, exenatide might confer cardioprotection after acute myocardial infarction (MI).. Pigs were randomized to exenatide or phosphate-buffered saline (PBS) treatment after 75 min of coronary artery ligation and subsequent reperfusion. Infarct size was assessed with Evans Blue (Sigma-Aldrich, St. Louis, Missouri) and triphenyltetrazolium chloride. Cardiac function was measured with epicardial ultrasound and conductance catheter-based pressure-volume loops. Western blotting, histology, and activity assays were performed to determine markers of apoptosis/survival and oxidative stress.. Exenatide reduced myocardial infarct size (32.7 +/- 6.4% vs. 53.6 +/- 3.9%; p = 0.031) and prevented deterioration of systolic and diastolic cardiac function (systolic wall thickening: 47.3 +/- 6.3% vs. 8.1 +/- 1.9%, p < 0.001; myocardial stiffness: 0.12 +/- 0.06 mm Hg/ml vs. 0.22 +/- 0.07 mm Hg/ml; p = 0.004). After exenatide treatment, myocardial phosphorylated Akt and Bcl-2 expression levels were higher compared with those after PBS treatment, and active caspase 3 expression was lower. In addition, fewer cells were terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling-positive. In addition, nuclear oxidative stress as assessed with an 8-hydroxydeoxyguanosine staining was reduced in the exenatide treatment arm, and superoxide dismutase activity and catalase activity were increased. Serum insulin levels increased after exenatide treatment, without affecting glucose levels.. These data identify exenatide as a potentially effective compound to reduce infarct size in adjunction to reperfusion therapy in patients with acute MI.

Topics: Animals; Disease Models, Animal; Exenatide; Hypoglycemic Agents; Myocardial Infarction; Myocardial Reperfusion Injury; Peptides; Swine; Venoms

Topics: Animals; Electrocardiography; Exenatide; Hospital Mortality; Humans; Hypoglycemic Agents; Myocardial Infarction; Myocardial Reperfusion Injury; Peptides; Treatment Outcome; Venoms