Opioids in Remote Ischemic Preconditioning-Induced Cardioprotection

Slowly activating voltage-gated potassium current potentiation by ML277 is a novel cardioprotective intervention

Cardiovascular disease is thought to account for nearly a third of deaths worldwide, with ischemic heart disease, including acute coronary syndromes such as myocardial infarction, accounting for 1.7 million deaths per year. There is a clear need for interventions to impart cardioprotection against ischemia. Here, we show that the slowly activating voltage-gated potassium current (IKs) potentiator ML277 imparts cardioprotection against ischemia in cellular and whole-heart models by modulating the action potential duration. In three different metabolic inhibition and reperfusion models, an increased contractile recovery and cell survival was observed with ML277, indicative of protection. Finally, ML277 reduced infarct size in an ex vivo Langendorff coronary ligation model, including if only applied on reperfusion. In conclusion, potentiation of the IKs with ML277 imparted a cardioprotection that was equivalent to the protection reported previously by ischemic preconditioning. These data suggest that IKs potentiation may be therapeutically useful in acute coronary syndromes.

Exercise Training: The Holistic Approach in Cardiovascular Prevention

Nowadays, there are robust clinical and pathophysiological evidence supporting the beneficial effects of physical activity on cardiovascular (CV) system. Thus, the physical activity is considered a key strategy for CV prevention. In fact, exercise training exerts favourable effects on all risk factors for CV diseases (i.e. essential hypertension, type 2 diabetes mellitus, hypercholesterolemia, obesity, metabolic syndrome, etc…). In addition, all training modalities such as the aerobic (continuous walking, jogging, cycling, etc.) or resistance exercise (weights), as well as the leisure-time physical activity (recreational walking, gardening, etc) prevent the development of the major CV risk factors, or delay the progression of target organ damage improving cardio-metabolic risk. Exercise training is also the core component of all cardiac rehabilitation programs that have demonstrated to improve the quality of life and to reduce morbidity in patients with CV diseases, mostly in patients with coronary artery diseases. Finally, it is still debated whether or not exercise training can influence the occurrence of atrial and ventricular arrhythmias. In this regard, there is some evidence that exercise training is protective predominantly for atrial arrhythmias, reducing the incidence of atrial fibrillation. In conclusion, the salutary effects evoked by physical acitvity are useful in primary and secondary CV prevention.

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.

Impact of Morphine Treatment With and Without Metoclopramide Coadministration on Myocardial and Microvascular Injury in Acute Myocardial Infarction: Insights From the Randomized MonAMI Trial

Background

Intravenous morphine administration can adversely affect platelet inhibition induced by P2Y₁₂ receptor inhibitors after acute myocardial infarction. In contrast, some evidence suggests that opioid agonists may have cardioprotective effects on the myocardium. The aim of this prospective, randomized MonAMI (Impact of Morphine Treatment With and Without Metoclopramide Coadministration on Platelet Inhibition in Acute Myocardial Infarction) trial was, therefore, to investigate the impact of morphine with or without metoclopramide coadministration on myocardial and microvascular injury.

Methods and Results

Patients with acute myocardial infarction (n=138) were assigned in a 1:1:1 ratio to ticagrelor 180 mg plus: (1) intravenous morphine 5 mg (morphine group); (2) intravenous morphine 5 mg and metoclopramide 10 mg (morphine+metoclopramide group); or (3) intravenous placebo (control group) administered before primary percutaneous coronary intervention. Cardiac magnetic resonance imaging was performed in 104 patients on day 1 to 4 after the index event. Infarct size was significantly smaller in the morphine only group as compared with controls (percentage of left ventricular mass, 15.5 versus 17.9; P=0.047). Furthermore, the number of patients with microvascular obstruction was significantly lower after morphine administration (28% versus 54%; P=0.022) and the extent of microvascular obstruction was smaller (percentage of left ventricular mass, 0 versus 0.74; P=0.037). In multivariable regression analysis, morphine administration was independently associated with a reduced risk for the occurrence of microvascular obstruction (odds ratio, 0.37; 95% CI, 0.14–0.93 [P=0.035]). There was no significant difference in infarct size (P=0.491) and extent (P=0.753) or presence (P=0.914) of microvascular obstruction when comparing the morphine+metoclopramide group with the control group.

Conclusions

In this randomized study, intravenous administration of morphine before primary percutaneous coronary intervention resulted in a significant reduction of myocardial and microvascular damage following acute myocardial infarction. This effect was not observed in the morphine plus metoclopramide group.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02627950.

Late Phases of Cardioprotection During Remote Ischemic Preconditioning and Adenosine Preconditioning Involve Activation of Neurogenic Pathway

BACKGROUND

The role of the neurogenic pathway in early phases of cardioprotection during remote ischemic preconditioning (RIPC) and adenosine preconditioning is reported.

AIM

This study was designed to explore the involvement of the neurogenic pathway in late phases of cardioprotection during RIPC and adenosine preconditioning.

MATERIAL AND METHODS

Fifty-four Wistar rats were used and divided into 9 experimental groups. RIPC was induced by tying the blood pressure cuff around the hind limb and subjecting to 4 cycles of inflation and deflation of 5 minutes each. In early RIPC, the heart was isolated immediately after the last episode of RIPC, whereas in late RIPC, the heart was isolated 24 hours after the last cycle of RIPC. In a similar way, adenosine preconditioning was instituted in early and late phases by either isolating the heart 40 minutes or 24 hours after adenosine (4 mg/kg, intraperitoneally [i.p.]) administration. Isolated hearts were subjected to ischemia-reperfusion (I/R) injury on the Langendorff's system.

RESULTS

Both early and late phases of RIPC and adenosine preconditioning significantly abrogated I/R-induced myocardial injury in terms of decrease in the release of lactate dehydrogenase, creatine kinase, and decrease in infarct size. Pretreatment with hexamethonium, a ganglion blocker (20 mg/kg, i.p.), significantly abolished the cardioprotective effects of both early and late phases of RIPC and adenosine preconditioning.

CONCLUSION

Apart from the involvement of the neurogenic pathway in the early phases, there is a critical role of the neurogenic pathway in the late phase of cardioprotection during RIPC and adenosine preconditioning.

Bioactive Signaling in Next-Generation Pharmacotherapies for Heart Failure: A Review

Importance

The standard pharmacotherapy for heart failure (HF), particularly HF with reduced ejection fraction (HFrEF), is primarily through the use of receptor antagonists, notably inhibition of the renin-angiotensin system by either angiotensin-converting enzyme inhibition or angiotensin II receptor blockade (ARB). However, the completed Prospective Comparison of ARNI With an ACE-Inhibitor to Determine Impact on Global Mortality and Morbidity in Heart Failure (PARADIGM-HF) trial identified that the use of a single molecule (sacubitril/valsartan), which is an ARB and the neutral endopeptidase inhibitor (NEPi) neprilysin, yielded improved clinical outcomes in HFrEF compared with angiotensin-converting enzyme inhibition alone.

Observations

This review examined specific bioactive signaling pathways that would be potentiated by NEPi and how these would affect key cardiovascular processes relevant to HFrEF. It also addressed potential additive/synergistic effects of ARB. A number of biological signaling pathways that may be potentiated by sacubitril/valsartan were identified, including some novel candidate molecules, which will act in a synergistic manner to favorably alter the natural history of HFrEF.

Conclusions and Relevance

This review identified that activation rather than inhibition of specific receptor pathways provided favorable cardiovascular effects that cannot be achieved by renin-angiotensin system inhibition alone. Thus, an entirely new avenue of translational and clinical research lies ahead in which HF pharmacotherapies will move beyond receptor antagonist strategies.

The application of remote ischemic conditioning in cardiac surgery

Perioperative myocardial ischemia and infarction are the leading causes of morbidity and mortality following anesthesia and surgery. The discovery of endogenous cardioprotective mechanisms has led to testing of new methods to protect the human heart. These approaches have included ischemic pre-conditioning, per-conditioning, post-conditioning, and remote conditioning of the myocardium. Pre-conditioning and per-conditioning include brief and repetitive periods of sub-lethal ischemia before and during prolonged ischemia, respectively; and post-conditioning is applied at the onset of reperfusion. Remote ischemic conditioning involves transient, repetitive, non-lethal ischemia and reperfusion in one organ or tissue (remote from the heart) that renders myocardium more resistant to lethal ischemia/reperfusion injury. In healthy, young hearts, many conditioning maneuvers can significantly increase the resistance of the heart against ischemia/reperfusion injury. The large multicenter clinical trials with ischemic remote conditioning have not been proven successful in cardiac surgery thus far. The lack of clinical success is due to underlying risk factors that interfere with remote ischemic conditioning and the use of cardioprotective agents that have activated the endogenous cardioprotective mechanisms prior to remote ischemic conditioning. Future preclinical research using remote ischemic conditioning will need to be conducted using comorbid models.