A Clinical Decision Support System for Remote Monitoring of Cardiovascular Disease Patients: A Clinical Study Protocol.

Introduction: Cardiovascular diseases (CVD) are the leading cause of death globally, taking an estimated 17. 9 million lives each year. Cardiac rehabilitation is shown to reduce mortality and hospital readmissions, while improving physical fitness and quality of life. Despite the recommendations and proven benefits, acceptance and adherence remain low. Mobile health (mHealth) solutions may contribute to more personalized and tailored patient recommendations according to their specific needs. This study protocol aims to assess the effectiveness of a user-friendly, comprehensive Clinical Decision Support System (CDSS) for remote patient monitoring of CVD patients, primarily on the reduction of recurrent cardiovascular events. Methods and Analysis: The study will follow a multicenter randomized controlled design involving two cardiology units in the Center Region of Portugal. Prospective CVD patients will be approached by the healthcare staff at each unit and checked for eligibility according to the predefined inclusion/exclusion criteria. The CDSS will suggest a monitoring plan for the patient, will advise the mHealth tools (apps and wearables) adapted to patient needs, and will collect data. The clinical study will start in January 2023. Discussion: The success of the mHeart.4U intervention will be a step toward the use of technological interfaces as an integrating part of CR programs. Ethics and Dissemination: The study will undergo ethical revision by the Ethics Board of the two hospital units where the study will unfold. The study was registered in ClinicalTrials.gov on 18th January 2022 with the number NCT05196802. The study findings will be published in international peer-reviewed scientific journals and encounters and in a user-friendly manner to the society.

Enhancing AMPK activation during ischemia protects the diabetic heart against reperfusion injury.

AMPK activation during ischemia helps the myocardium to cope with the deficit of energy production. As AMPK activity is considered to be impaired in diabetes, we hypothesized that enhancing AMPK activation during ischemia above physiological levels would protect the ischemic diabetic heart through AMPK activation and subsequent inhibition of mitochondrial permeability transition pore (mPTP) opening. Isolated perfused hearts from normoglycemic Wistar or diabetic Goto-Kakizaki (GK) rats (n ≥ 6/group) were subjected to 35 min of ischemia in the presence of 10, 20, and 40 µM of A-769662, a known activator of AMPK, followed by 120 min of reperfusion with normal buffer. Myocardial infarction and AMPK phosphorylation were assessed. The effect of A-769662 on mPTP opening in adult cardiomyocytes isolated from both strains was also determined. A-769662 at 20 µM reduced infarct size in both Wistar (30.5 ± 2.7 vs. 51.8 ± 3.9% vehicle; P < 0.001) and GK hearts (22.7 ± 3.0 vs. 48.5 ± 4.7% vehicle; P < 0.001). This protection was accompanied by a significant increase in AMPK and GSK-3ß phosphorylation. In addition, A-769662 significantly inhibited mPTP opening in both Wistar and GK cardiomyocytes subjected to oxidative stress. We demonstrate that AMPK activation during ischemia via A-769662 reduces myocardial infarct size in both the nondiabetic and diabetic rat heart. Furthermore, this cardioprotective effect appears to be mediated through inhibition of mPTP opening. Our findings suggest that improving AMPK activation during ischemia can be another mechanism for protecting the ischemic heart.

Transitory activation of AMPK at reperfusion protects the ischaemic-reperfused rat myocardium against infarction.

PURPOSE: AMPK plays a crucial role in the regulation of the energy metabolism of the heart. During ischaemia, AMPK activation is a known adaptative prosurvival mechanism that helps to maintain the energy levels of the myocardium. However, it still remains unclear if activation of AMPK during reperfusion is beneficial for the heart. Two known AMPK activators (metformin and AICAR) were used to verify the hypothesis that a transitory activation of AMPK at reperfusion may exert cardioprotection, as reflected in a reduction in myocardial infarct size. METHODS: Perfused rat hearts were subjected to 35 min ischaemia and 120 min reperfusion. Metformin (50 microM) or AICAR (0.5 mM) were added for 15 min at the onset of reperfusion alone or with Compound C (CC, 10 microM), an AMPK inhibitor. Infarct size and alpha-AMPK phosphorylation were measured. RESULTS: Metformin significantly reduced infarct size from 47.8 +/- 1.7% in control to 31.4 +/- 2.9%, an effect abolished by CC when the drugs were given concomitantly. Similarly, AICAR also induced a significant reduction in infarct size to 32.3 +/- 4.8%, an effect also abrogated by CC. However, metformin's protection was not abolished if CC was administered later in reperfusion. In addition, alpha-AMPK phosphorylation was significantly increased in the metformin treated group during the initial 30 min of reperfusion. CONCLUSIONS: Our data demonstrated that, in our ex vivo model of myocardial ischaemia-reperfusion injury, AMPK activation in early reperfusion is associated with a reduction in infarct size.

Micro-RNA Analysis in Pulmonary Arterial Hypertension: Current Knowledge and Challenges.

Pulmonary arterial hypertension (PAH) is a rare, chronic disease of the pulmonary vasculature that is associated with poor outcomes. Its pathogenesis is multifactorial and includes micro-RNA (miRNA) deregulation. The understanding of the role of miRNAs in PAH is expanding quickly, and it is increasingly difficult to identify which miRNAs have the highest translational potential. This review summarizes the current knowledge of miRNA expression in PAH, discusses the challenges in miRNA analysis and interpretation, and highlights 4 promising miRNAs in this field (miR-29, miR-124, miR-140, and miR-204).

Return to the past: myocardial regeneration therapy.

In recent years, myocardial regeneration therapy has been the subject of intense research. Several different cell lines and routes of administration have been tested and the main mechanisms of action are known. A substantial amount of data is available not only from the bench, but also from the bedside. However, there are still many unanswered questions about the safety and efficacy of this treatment The future of this therapy is uncertain at present, but it unquestionably has great potential. We await the results of ongoing clinical trials in order to have a clearer view of this field of research.

Nicorandil preserves the function of the mitochondrial phosphorylative and oxidative system in an animal model of global ischemia-reperfusion.

Ischemia followed by reperfusion (IR) negatively affects mitochondrial function. At the level of the oxidative-phosphorylative system, IR inhibits the respiratory complexes and ATP synthase, and increases the passive leak of protons through the inner mitochondrial membrane, uncoupling respiration from phosphorylation, decreasing mitochondrial potential and, consequently, ATP production. Drugs that minimize the mitochondrial damage induced by IR may prove to be clinically effective. In the present work, we analyzed the impact of nicorandil, a mitochondrial ATP-sensitive potassium channel agonist, on mitochondrial dysfunction at the level of the oxidative-phosphorylative system of rat hearts subjected to IR. The decrease in the respiratory control ratio (RCR) induced by IR leads to the conclusion that IR has a negative impact on the activity of the mitochondrial respiratory system, uncoupling oxidation from phosphorylation. This effect is reversed by nicorandil, which increases not only RCR, but also the ADP/O ratio. Regarding respiratory rate, state 3 rate was approximately the same for all the experimental groups, while state 4 rate was lower for the group where IR was induced in the presence of nicorandil. This result is in accordance with the data obtained for the RCR and ADP/O. State 4 rate is most affected by uncoupling, given that it is controlled by proton leak. Mitochondria subjected to IR in the presence of nicorandil have a lower state 4 rate, i.e. they are less uncoupled. From these results we conclude that nicorandil preserves the function of mitochondria subjected to IR in terms of both respiration and phosphorylative capacity.

Valsartan improves mitochondrial function in hearts submitted to acute ischemia.

The effect of valsartan, an angiotensin II-type I receptor blocker, on the mitochondrial function, was studied using an ex vivo animal model (hearts from Wistar rats), perfused in a Langendorff system and then submitted to global acute ischemia. Parameters evaluated were: membrane electrical potential (DeltaPsi, using a tetraphenylphosphonium-TPP+-electrode), oxygen consumption by the respiratory chain (Clark-type O2 electrode), phosphorylation lag phase (time necessary to phosphorylate a fixed amount of ADP) and ATP/ADP ratio (adenine nucleotides quantified by high-pressure liquid chromatography-HPLC). Valsartan acts preferentially in the phosphorylation, increasing ATP/ADP ratios (succinate: 1.6+/-0.4 versus 0.5+/-0.1--P<0.05; ascorbate/N,N,N',N'-tetramethyl-P-phenylenodiamine-TMPD: 1.1+/-0.2 versus 0.4+/-0.1--p<0.05 versus ischemia in the absence of valsartan) and decreasing lag phase (glutamate/malate: 50.0+/-9.6 s versus 127.2+/-19.03 s-84.6+/-16.2% versus 215.3+/-32.2%; P=0.01; succinate: 111.8+/-33.1 s versus 275.73+/-45.99 s-168.2+/-49.8% versus 414.9+/-69.2%; P=0.02 or ascorbate/TMPD: 11.0+/-3.9 s versus 62.4+/-11.63 s-34.9+/-12.4% versus 198.1+/-36.9%; P=0.001 versus ischemia in the absence of valsartan). This enables a higher energy production in hearts submitted to acute ischemia, for which having energy becomes critical to preserve mitochondrial function. These mechanisms allow us to better understand valsartan cytoprotection in ischemic cardiomyopathy.

Impact of acute ischemia-reperfusion on myocardial mitochondrial function in an ex-vivo model of global myocardial ischemia.

INTRODUCTION: Cardiac mitochondria, as the major source of energy used by the heart, play an important part in the survival of cardiomyocytes undergoing ischemia followed by reperfusion. During ischemia, cardiac mitochondria represent one of the main cellular defense mechanisms, acting as a calcium-sequestering system and maintaining levels of energy production. However, when these cellular mechanisms are overcome, loss of mitochondrial integrity leads not only to the breakdown of energy production, but also to the release of pro-apoptotic factors, thus compromising the survival of cardiac cells. OBJECTIVES: To study the impact of acute ischemia-reperfusion (IR) on myocardial mitochondrial function in an ex-vivo model of global ischemia. METHODS: Wistar rat hearts were divided into two groups: control (165 minutes of perfusion with Krebs-Henseleit solution) and ischemia-reperfusion (IR - 10 minutes perfusion, followed by 35 minutes ischemia and 120 minutes reperfusion). Various parameters of mitochondrial function were assessed: respiratory control ratio (RCR) using a Clark-type oxygen electrode, oxidative stress (using the thiobarbituric acid reactive substances [TBARS] test), and mitochondrial swelling amplitude and calcium uptake, both determined by fluorimetric methods. RESULTS: All mitochondrial parameters were severely affected by IR. The IR group showed a significant decrease in RCR, which was independent of the respiratory substrate used, for each assay. There were no significant differences between the two experimental groups in TBARS production. The control group showed a trend for a decrease in mitochondrial swelling amplitude and an increase in calcium uptake compared to the IR group, in both the absence and presence of cyclosporin A. CONCLUSIONS: In this study, IR significantly altered mitochondrial function (RCR, mitochondrial swelling amplitude and intramitochondrial calcium uptake). This means that during acute myocardial ischemia, every effort should be made to avoid reperfusion injury, given its deleterious consequences for coronary artery disease patients.

Impact of imidapril on cardiac mitochondrial function in an ex-vivo animal model of global myocardial ischemia.

Imidapril is an angiotensin I converting enzyme inhibitor, a class of drugs with known cardioprotective activity. It is now known that this is due not only to their antihypertensive activity, but also to the fact that they decrease cellular and tissue levels of angiotensin II, a potent vasoconstrictor and inducer of myocardial fibrosis. These mechanisms may explain the good clinical results of this class of drugs in the treatment of coronary artery disease and heart failure, two diseases whose etiopathogenesis is closely related to the activation of the renin-angiotensin-aldosterone system. However, the impact of this class of drugs on cardiac mitochondrial function during acute myocardial ischemia is still largely unknown. With the aim of studying the effect of imidapril on cardiac mitochondrial function during acute ischemia, we used an ex-vivo animal model, perfused in a Langerdorff system and then subjected to ischemia in the presence or absence of imidapril. We evaluated mitochondrial membrane electrical potential, respiratory chain O2 consumption, and rate and amplitude of mitochondrial swelling. We conclude that imidapril did not significantly change oxygen consumption by cardiac mitochondria, as assessed by the rate of respiratory state 3 (the state that corresponds to the active phosphorylation phase). However, imidapril significantly increased transmembrane electrical potential and, in ischemic cardiac mitochondria, was able to prevent the calcium-induced increase in the rate and amplitude of mitochondrial swelling, thus enabling better preservation of mitochondrial membrane structure, with consequent improvement of electrical potential after the phosphorylation cycle. These findings enabled a better understanding of the mechanisms behind the cytoprotection provided by imidapril during ischemic cardiomyopathy, clearly highlighting, at a cellular biology level, the importance of pharmacological modulation of cardiac mitochondrial function during acute ischemia.

Carvedilol improves energy production during acute global myocardial ischaemia.

Cardiac mitochondria may become dysfunctional during ischaemia, thus compromising cardiomyocyte function. Carvedilol is an alpha(1)/beta-adrenoceptor antagonist with antioxidant, neuroprotective, cardioprotective and vascularprotective properties, and is used to treat hypertension, myocardial ischaemia and congestive heart failure. However, its impact on mitochondrial function during acute prolonged ischaemia is unknown. We aimed to study the effect of carvedilol on cardiac mitochondrial function during acute ischaemia, using Wistar rat hearts perfused with a Langendorff system, and then submitted to ischaemia in the presence and absence of carvedilol. We determined the electrical potential of the mitochondrial membrane, O(2) consumption by the respiratory chain, energy charge and the activity of the mitochondrial respiratory chain complexes. In our model, carvedilol had a preferential action on phosphorylation, increasing the mitochondrial energy charge (0.76+/-0.03 vs. 0.65+/-0.01 arbitrary units; P<0.05) and decreasing the phosphorylation lag phase (28.64+/-4.23 vs. 62.4+/-11.63 s; P<0.05) during ischaemia. The larger amount of energy available allowed the preservation of the electrical potential (201.2+/-2.45 vs. 186.66+/-3.36 mV;P<0.05), thus improving mitochondrial function during acute prolonged ischaemia.

Protective effect of trimetazidine on myocardial mitochondrial function in an ex-vivo model of global myocardial ischemia.

Trimetazidine is an anti-ischemic drug whose cytoprotective mechanisms are not yet fully understood (but until now mainly related to the trimetazidine-induced "metabolic shift" from lipid beta-oxidation to glucose aerobic oxidation). We studied the effect of trimetazidine on the mitochondrial function of ischemic Wistar rat hearts perfused with glucose, using a model of ex-vivo perfusion (Langendorff system). We measured the electrical potential of the mitochondrial membrane, O2 consumption by the respiratory chain, energy charges generated and the enzyme activities of the respiratory chain complexes. In this model, trimetazidine had a preferential action on the oxidative system (mainly on complex I), increasing its enzyme activity and decreasing O2 consumption after phosphorylation; this could decrease oxygen free radical production and increase mitochondrial integrity, thus allowing the maintenance of the electrical potential. These results allow us to better understand the cytoprotective effects of trimetazidine in coronary artery disease.

[Physiopathologic mechanisms of ventricular remodelling]. / Mecanisoms fisiopatológicos da remodelação ventricular.

Understanding of the pathophysiological mechanisms involved in ventricular remodeling is of the utmost importance for the clinical cardiologist. In the near future this knowledge will allow us not only to better understand the evolution of patients suffering from this process but also to design new therapeutic strategies for the prevention of ventricular remodeling. In this work some of the main pathophysiological mechanisms involved in ventricular remodeling are briefly reviewed.

Long-term clinical impact of coronary-collateral vessels after acute myocardial infarction.

BACKGROUND: The positive impact of coronary collateral vessels in the acute phase of myocardial infarction (AMI) is already well established. However, their impact on longterm clinical outcome of these patients is still unclear. AIM: To study the impact of the presence of well established coronary collateral vessels on long-term clinical outcome of post-AMI patients. POPULATION AND METHODS: We analyzed the clinical evolution (mean follow-up time of 15.66.8 months) of 70 patients who underwent coronary angiography shortly after AMI. According to the angiogram, the patients were divided into 2 groups: those with well developed coronary collateral vessels (n = 35) and those who did not show developed collateral circulation (n = 35). RESULTS: Both groups had similar baseline characteristics (regarding demography, coronary artery disease risk factors and predischarge evolution). The group with collaterals had more severe coronary disease compared with the group without collaterals (2.31 +/- 0.61 vs. 1.57 +/- 0.7; p = 0.00001). Moreover, this group more frequently showed significant lesions on the left anterior descending artery (83% vs. 74%; p = NS), left circumflex (71% vs. 43%; p = 0.02) and right coronary arteries (74% vs. 40%; p = 0.003). Primary percutaneous coronary intervention was more often performed in patients without coronary collateral vessels (58% vs. 30%; p = 0.02). Left ventricular function was similar in both groups. During follow-up, both groups underwent similar levels of revascularization by percutaneous coronary intervention and/or coronary artery bypass graft (70% vs. 76%; p = NS). Despite these characteristics, the group with collaterals showed a significantly better clinical outcome, with fewer events (combined endpoint of unstable angina, non-fatal AMI, heart failure and death) after hospital discharge (40% vs. 69%; p = 0.02) and a lower CCS functional class at the end of follow-up (1.26 +/- 0.63 vs. 1.730.71; p = 0.03). CONCLUSION: After acute myocardial infarction, the presence of collateral vessels is associated with a better long-term clinical outcome.

Carvedilol protects ischemic cardiac mitochondria by preventing oxidative stress.

Ischemia negatively affects mitochondrial function by inducing the mitochondrial permeability transition (MPT). The MPT is triggered by oxidative stress, which occurs in mitochondria during ischemia as a result of diminished antioxidant defenses and increased reactive oxygen species production. It causes mitochondrial dysfunction and can ultimately lead to cell death. Therefore, drugs able to minimize mitochondrial damage induced by ischemia may prove to be clinically effective. We analyzed the effect of carvedilol, a beta-blocker with antioxidant properties, on mitochondrial dysfunction. Carvedilol decreased levels of TBARS (thiobarbituric acid reactive substances), an indicator of oxidative stress, which is consistent with its antioxidant properties. Regarding cell death by apoptosis, although ischemia did increase caspase-8-like activity, there were no changes in caspase-3-like activity, which is activated downstream of caspase-8; this may indicate that the apoptotic cascade is not activated by 60 minutes of ischemia. We conclude that carvedilol protects ischemic mitochondria by preventing oxidative mitochondrial damage, and, by so doing, it may also inhibit the formation of the MPT pore.