How Can Malnutrition Affect Autophagy in Chronic Heart Failure? Focus and Perspectives.

Chronic heart failure (CHF) is a disease with important clinical and socio-economic ramifications. Malnutrition and severe alteration of the protein components of the body (protein disarrangements), common conditions in CHF patients, are independent correlates of heart dysfunction, disease progression, and mortality. Autophagy, a prominent occurrence in the heart of patients with advanced CHF, is a self-digestive process that prolongs myocardial cell lifespan by the removal of cytosolic components, such as aging organelles and proteins, and recycles the constituent elements for new protein synthesis. However, in specific conditions, excessive activation of autophagy can lead to the destruction of molecules and organelles essential to cell survival, ultimately leading to organ failure and patient death. In this review, we aim to describe the experimental and clinical evidence supporting a pathophysiological role of nutrition and autophagy in the progression of CHF. The understanding of the mechanisms underlying the interplay between nutrition and autophagy may have important clinical implications by providing molecular targets for innovative therapeutic strategies in CHF patients.

Elevated Cardiac Troponin in Clinical Scenarios Beyond Obstructive Coronary Artery Disease.

In this systematic review article, we aim to summarize the most up-to-date evidence regarding elevations of cardiac troponin, especially in clinical scenarios other than obstructive coronary artery disease. The accurate interpretation of raised cardiac troponin is challenging because it relies on unconfirmed postulations and dogmatic knowledge (e.g., the exclusive provenience of cardiac troponin from cardiac myocytes), based on which every troponin elevation is assumed to definitely indicate myocardial damage. Indeed, the investigation of the pathophysiologic mechanism leading to the release in the bloodstream of cardiac biomarkers should be the first step of the diagnostic process to fully understand the clinical significance of the elevated serum levels and identify the best management. A prominent effort should be put in place to identify the contribution of potential confounding factors, both cardiac and non-cardiac in etiology, with the ability to affect synthesis and clearance of cardiac biomarkers. Regardless of the underlying cause, it is well established that cardiovascular biomarkers are increasingly useful to further risk stratification and prognosticate patients. Accordingly, we sought to clarify the meaning and impact of elevated cardiac troponin in those frequently encountered real-world scenarios presenting clinicians with a diagnostic dilemma, with the final goal of facilitating the diagnosis and help optimize individually tailored treatment strategies.

Cardioprotection by minocycline in a rabbit model of ischemia/reperfusion injury: Detection of cell death by in vivo 111In-GSAO SPECT.

BACKGROUND: Preclinical studies indicate that minocycline protects against myocardial ischemia/reperfusion injury. In these studies, minocycline was administered before ischemia, which can rarely occur in clinical practice. The current study aimed to evaluate cardioprotection by minocycline treatment upon reperfusion. METHODS: Rabbits were subjected to myocardial ischemia/reperfusion injury and received either intravenous minocycline (n = 8) or saline (n = 8) upon reperfusion. Cardiac cell death was assessed by in vivo micro-SPECT/CT after injection of Indium-111-labeled 4-(N-(S-glutathionylacetyl)amino) phenylarsonous acid (111In-GSAO). Thereafter, hearts were explanted for ex vivo imaging, γ-counting, and histopathological characterization. RESULTS: Myocardial damage was visualized by micro-SPECT/CT imaging. Quantitative GSAO uptake (expressed as percent injected dose per gram, %ID/g) in the area at risk was lower in minocycline-treated animals than that in saline-treated control animals (0.32 ± 0.13% vs 0.48 ± 0.15%, P = 0.04). TUNEL staining confirmed the reduction of cell death in minocycline-treated animals. CONCLUSIONS: This study demonstrates cardioprotection by minocycline in a clinically translatable protocol.

Comprehensive review on cardio-oncology: Role of multimodality imaging.

Cancer and cardiovascular disease are the two leading causes of mortality worldwide. Evolving oncologic therapy, including the use of newer targeted agents, has led to an improvement in survival from childhood- and adult-onset cancers. Consequently, there has been a growing realization of cardiotoxic complications related to cancer therapy, with some complications manifesting over months to decades after completion of cancer treatment. This paper reviews cancer therapeutics-related cardiovascular toxicity and its manifestations, multimodality imaging techniques for surveillance and detection of this complication, and the current state of knowledge in this emerging field.

Role of calcium desensitization in the treatment of myocardial dysfunction after deep hypothermic circulatory arrest.

INTRODUCTION: Rewarming from deep hypothermic circulatory arrest (DHCA) produces calcium desensitization by troponin I (cTnI) phosphorylation which results in myocardial dysfunction. This study investigated the acute overall hemodynamic and metabolic effects of epinephrine and levosimendan, a calcium sensitizer, on myocardial function after rewarming from DHCA. METHODS: Forty male Wistar rats (400 to 500 g) underwent cardiopulmonary bypass (CPB) through central cannulation and were cooled to a core temperature of 13°C to 15°C within 30 minutes. After DHCA (20 minutes) and CPB-assisted rewarming (60 minutes) rats were randomly assigned to 60 minute intravenous infusion with levosimendan (0.2 µg/kg/min; n = 15), epinephrine (0.1 µg/kg/min; n = 15) or saline (control; n = 10). Systolic and diastolic functions were evaluated at different preloads with a conductance catheter. RESULTS: The slope of left ventricular end-systolic pressure volume relationship (Ees) and preload recruitable stroke work (PRSW) recovered significantly better with levosimendan compared to epinephrine (Ees: 85 ± 9% vs 51 ± 11%, P<0.003 and PRSW: 78 ± 5% vs 48 ± 8%, P<0.005; baseline: 100%). Levosimendan but not epinephrine reduced left ventricular stiffness shown by the end-diastolic pressure-volume relationship and improved ventricular relaxation (Tau). Levosimendan preserved ATP myocardial content as well as energy charge and reduced plasma lactate concentrations. In normothermia experiments epinephrine in contrast to Levosimendan increased cTnI phosphorylation 3.5-fold. After rewarming from DHCA, cTnI phosphorylation increased 4.5-fold in the saline and epinephrine group compared to normothermia but remained unchanged with levosimendan. CONCLUSIONS: Levosimendan due to prevention of calcium desensitization by cTnI phosphorylation is more effective than epinephrine for treatment of myocardial dysfunction after rewarming from DHCA.

Targeting urocortin signaling pathways to enhance cardioprotection: is it time to move from bench to bedside?

Despite the exponential growth in medical knowledge, cardiovascular diseases (CVDs) contribute to more than one-third of worldwide morbidity and mortality. A range of therapies already exist for established CVDs, although there is significant interest in further understanding their pathogenesis. The urocortins (Ucns) are peptide members of the corticotrophin-releasing factor family, a group of evolutionary conserved peptides with homologues in fish, amphibians and mammals and considered to play a pivotal role in energy homeostasis and local tissue repair. A number of preclinical studies in vitro, in-vivo and ex-vivo have defined a multifaceted effect of Ucns on the cardiovascular system. Different G-protein coupled signaling and protein-kinase pathways have been shown to be activated by Ucns, together with different transcriptional and translational effects, all of which preferentially converge on the mitochondria, where the modulation of apoptosis is considered their principal action. It has been demonstrated in experimental models, and consequentially suggested in human diseases, that Ucn-mediated inhibition of apoptosis can be exploited for the improvement of both therapeutic and preventative strategies against CVDs. Specifically, some unavoidable iatrogenic ischemia/reperfusion (I/R) injuries, e.g. during cardiac surgery or percutaneous coronary angioplasty, may greatly benefit from the anti-apoptotic effect of Ucns. However, few studies on the topic have been employed in humans to date. Therefore, this review will focus on the different intra-cellular mechanisms of action of Urocortins, and detail the different Ucn-mediated pathways identified so far. It will also highlight the limited evidence already existing in human clinical and surgical settings, as well as emphasize the potential uses of Ucns in human cardiac pathology.

Essential Amino Acids-Rich Diet Increases Cardiomyocytes Protection in Doxorubicin-Treated Mice.

BACKGROUND: Doxorubicin (Doxo) is a widely prescribed drug against many malignant cancers. Unfortunately, its utility is limited by its toxicity, in particular a progressive induction of congestive heart failure. Doxo acts primarily as a mitochondrial toxin, with consequent increased production of reactive oxygen species (ROS) and attendant oxidative stress, which drives cardiac dysfunction and cell death. A diet containing a special mixture of all essential amino acids (EAAs) has been shown to increase mitochondriogenesis, and reduce oxidative stress both in skeletal muscle and heart. So, we hypothesized that such a diet could play a favorable role in preventing Doxo-induced cardiomyocyte damage. METHODS: Using transmission electron microscopy, we evaluated cells' morphology and mitochondria parameters in adult mice. In addition, by immunohistochemistry, we evaluated the expression of pro-survival marker Klotho, as well as markers of necroptosis (RIP1/3), inflammation (TNFα, IL1, NFkB), and defense against oxidative stress (SOD1, glutathione peroxidase, citrate synthase). RESULTS: Diets with excess essential amino acids (EAAs) increased the expression of Klotho and enhanced anti-oxidative and anti-inflammatory responses, thereby promoting cell survival. CONCLUSION: Our results further extend the current knowledge about the cardioprotective role of EAAs and provide a novel theoretical basis for their preemptive administration to cancer patients undergoing chemotherapy to alleviate the development and severity of Doxo-induced cardiomyopathy.

Follicular B-Cell Lymphoma and Particulate Matter Associated with Environmental Exposure to Wood Dust.

BACKGROUND In humans, wood dust is a carcinogen. Indeed, a strong association between wood dust and lung cancer risk has been reported in woodworkers, as well as in the general population. CASE REPORT The patient was a 58-year-old man with follicular B-cell lymphoma. In the 10 years preceding the cancer diagnosis, he lived within 1/4 mile of a paper mill, where wood was processed. Computed tomography of the chest, abdomen, and pelvis revealed right hilar, mediastinal, abdominal, and retroperitoneal lymphadenopathy, bilateral pleural effusions, and a large soft-tissue mass infiltrating the small bowel mesentery. Analysis of the pleural fluid revealed the presence of a web of thin filopodia-like filaments, which trapped clusters of mesothelial cells and atypical lymphocytes. Single tubular filaments, morphologically similar to tunneling nanotubes, were seen originating from atypical lymphocytes and reaching neighboring cells. Furthermore, long, thick, cylindrical fibers of unknown nature, probably from the external environment, were also observed. CONCLUSIONS Because the patient lived in an unhealthy environment for many years, the possibility that his clinical condition was related to exposure to toxic emissions should be entertained. Considered in this context, the foreign fibers in his pleural fluid could be a direct consequence of inhalation of contaminants in the polluted air.

Management of Anaemia of Chronic Disease: Beyond Iron-Only Supplementation.

Chronic diseases are characterised by altered autophagy and protein metabolism disarrangement, resulting in sarcopenia, hypoalbuminemia and hypo-haemoglobinaemia. Hypo-haemoglobinaemia is linked to a worse prognosis independent of the target organ affected by the disease. Currently, the cornerstone of the therapy of anaemia is iron supplementation, with or without erythropoietin for the stimulation of haematopoiesis. However, treatment strategies should incorporate the promotion of the synthesis of heme, the principal constituent of haemoglobin (Hb) and of many other fundamental enzymes for human metabolism. Heme synthesis is controlled by a complex biochemical pathway. The limiting step of heme synthesis is D-amino-levulinic acid (D-ALA), whose availability and synthesis require glycine and succinil-coenzyme A (CoA) as precursor substrates. Consequently, the treatment of anaemia should not be based only on the sufficiency of iron but, also, on the availability of all precursor molecules fundamental for heme synthesis. Therefore, an adequate clinical therapeutic strategy should integrate a standard iron infusion and a supply of essential amino acids and vitamins involved in heme synthesis. We reported preliminary data in a select population of aged anaemic patients affected by congestive heart failure (CHF) and catabolic disarrangement, who, in addition to the standard iron therapy, were treated by reinforced therapeutic schedules also providing essential animo acids (AAs) and vitamins involved in the maintenance of heme. Notably, such individualised therapy resulted in a significantly faster increase in the blood concentration of haemoglobin after 30 days of treatment when compared to the nonsupplemented standard iron therapy.

Serum Metabolic Profile in Patients With Long-Covid (PASC) Syndrome: Clinical Implications.

Background: Many patients who have been suffering by Covid-19 suffer of long-Covid syndrome, with symptoms of fatigue and muscular weakness that characterize post-acute sequelae SARS-CoV-2 infection (PASC). However, there is limited knowledge about the molecular pathophysiology, and about the serum profile of these patients. Methods: We studied the blood serum profile of 75 selected patients, with previous confirmed Covid-19, 2 months after hospital discharge, who reported new-onset fatigue, muscle weakness and/or dyspnea not present prior to the virus infection and independently from concomitant diseases and/or clinical conditions. Results: All patients had very high serum concentrations of ferritin and D-Dimer. 87 and 72% of patients had clinically significant low levels of hemoglobin and albumin, respectively. Seventy three percentage had elevations in erythrocyte sedimentation rate and CRP. Twenty seven percentage had elevations in LDH. Conclusions: The co-existence of patient symptoms along with blood markers of coagulation, protein disarrangement and inflammation suggests ongoing alterations in the metabolism, promoting an inflammatory/hypercatabolic state which maintains a vicious circles implicated in the persistence of PASC. The persistence of altered D-Dimer levels raises the possibility of long-term risks of thromboembolic disease. All these markers levels should be accurately evaluated in the long-term follow-up, with individualized consideration for prophylactic nutritional, anti-inflammatory and/or anticoagulant therapy if indicated.

STAT3 modulates the DNA damage response pathway.

The STAT3 transcription factor is well known to function as an anti-apoptotic factor, especially in numerous malignancies. Recently we showed that STAT3 is cytoprotective and that cells lacking STAT3 are more sensitive to oxidative stress. A key feature of oxidative stress involves activation of the DNA damage pathway. However, a role for STAT3 or its contribution in response to DNA damage has not been described. In the present study we show that cells lacking STAT3 are less efficient in repairing damaged DNA. Moreover, STAT3 deficient cells show reduced activity of the ATM-Chk2 and ATR-Chk1 pathways, both important pathways in sensing DNA damage. Finally we show that MDC1, a regulator of the ATM-Chk2 pathway and facilitator of the DNA damage response, is modulated by STAT3 at the transcriptional level. These findings demonstrate that STAT3 is necessary for efficient repair of damaged DNA, partly by modulating the ATM-Chk2 and ATR-Chk1 pathways.

STAT3 deletion sensitizes cells to oxidative stress.

The transcription factor STAT1 plays a role in promoting apoptotic cell death, whereas the related STAT3 transcription factor protects cardiac myocytes from ischemia/reperfusion (I/R) injury or oxidative stress. Cytokines belonging to the IL-6 family activate the JAK-STAT3 pathway, but also activate other cytoprotective pathways such as the MAPK-ERK or the PI3-AKT pathway. It is therefore unclear whether STAT3 is the only cytoprotective mediator against oxidative stress-induced cell death. Overexpression of STAT3 in primary neonatal rat ventricular myocytes (NRVM) protects against I/R-induced cell death. Moreover, a dominant negative STAT3 adenovirus (Ad ST3-DN) enhanced apoptotic cell death (81.2+/-6.9%) compared to control infected NRVM (46.0+/-3.1%) following I/R. Depletion of STAT3 sensitized cells to apoptotic cell death following oxidative stress. These results provide direct evidence for the role of STAT3 as a cytoprotective transcription factor in cells exposed to oxidative stress.

T-wave inversion: cardiac memory or myocardial ischemia?

This article presents a case report of a 74-year-old man with T-wave inversion (TwI) in atrial fibrillation noted during routine pacemaker interrogation. The patient was seen for routine pacemaker interrogation, at which time he was noted to have underlying atrial fibrillation. A12-lead electrocardiogram of the atrial fibrillation revealed significant TwIs. He was subsequently worked up for myocardial ischemia and was found to have a moderate-sized,moderate-degree inferior wall myocardial perfusion defect. He was subsequently referred for a cardiac catheterization. The cardiac catheterization revealed nonobstructive coronary artery disease. The follow-up electrocardiogram revealed persistent but attenuated TwI.The TwIs were attributed to cardiac memory, a common but infrequently recognized phenomenon of which many clinical practitioners are unaware. Cardiac memory is due to the T wave tracking the preceding abnormal QRS complex and can be induced by right ventricular pacing or arrhythmias.

Urocortin Induces Phosphorylation of Distinct Residues of Signal Transducer and Activator of Transcription 3 (STAT3) via Different Signaling Pathways.

BACKGROUND Urocortin (Ucn) is a member of the hypothalamic corticotrophin-releasing factor family and has been shown to reduce cell death in the heart caused by ischemia/reperfusion (I/R) injury. Signal transducer and activator of transcription 3 (STAT3) is a transcription factor known to function as a pro-survival and anti-apoptotic factor, whose activation depends on a variety of cytokines, including IL-6. A recent study demonstrated that urocortin induced IL-6 release from cardiomyocytes in a CRF-R2-dependent manner, suggesting a possible link between CRF-R2 stimulation and STAT3 activation. MATERIAL AND METHODS Experimental work was carried out in HL-1 cardiac myocytes exposed to serum starvation for 16-24 h. RESULTS Ucn stimulation led to IL-6 expression and release from mouse atrial HL-1 cardiomyocytes. Ucn treatment led to rapid phosphorylation of JAK2, which was blocked by the protein synthesis inhibitor cycloheximide or the JAK inhibitor AG490. Urocortin treatment induced STAT3 phosphorylation at Y705 and S727 through transactivation of JAK2 in an IL-6-dependent manner, but had no effect on STAT1 activity. Kinase inhibition experiments revealed that urocortin induces STAT3 S727 phosphorylation through ERK1/2 and Y705 phosphorylation through Src tyrosine kinase. In line with this finding, urocortin failed to induce phosphorylation of Y705 residue in SYF cells bearing null mutation of Src, while phosphorylation of S727 residue was unchanged. CONCLUSIONS Here, we have shown that Ucn induces activation of STAT3 through diverging signaling pathways. Full understanding of these signaling pathways will help fully exploit the cardioprotective properties of endogenous and exogenous Ucn.

Autophagy and Oncosis/Necroptosis Are Enhanced in Cardiomyocytes from Heart Failure Patients.

BACKGROUND Although originally described as a survival mechanism, it is unknown whether and to what extent autophagy is implicated in the terminal stages of heart failure. Here, we studied magnitude and evolution of autophagy in patients with intractable heart failure. MATERIAL AND METHODS Myocardial samples were obtained from 22 patients with ischemic cardiomyopathy and idiopathic dilated cardiomyopathy who were undergoing cardiac transplantation. Hearts from 11 patients who died from non-cardiac causes were used as control samples. Autophagy was evaluated by immunostaining with a monoclonal microtubule associated protein light chain 3 (LC3)-II antibody, while the relationship of autophagy with apoptosis and oncosis was assessed by double staining with TUNEL (terminal deoxynucleotidyl transferase - mediated deoxyuridine triphosphate nick end labeling) assay and complement 9 (C9) immunological staining, respectively. In addition, several necroptotic markers, including RIP1 and RIP3 (receptor interacting protein kinase 1 and 3), anti-C3 (cleaved-caspase-3), and anti-NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) were assessed by immunohistochemistry. RESULTS Anti-LC3-II staining was detected in 8.7±1.6% of the heart failure patient heart samples and in 1.2±0.3% of control patient heart samples. Vacuole formation started at one nuclear pole, before becoming bipolar and involving the cytosol. Subsequently, the autophagic process extended also to the nuclei, which underwent a progressive vacuolization and disintegration, assuming a peculiar "strawberry like appearance". Myocytes with extensive vacuole formation exhibited nuclear degeneration, which was associated with TUNEL, C3, C9, RIP1, and RIP3 positive staining. Conversely, myocytes with less extensive vacuole formation showed RIP1 and NF-κB positive staining, though not positivity for other cell death markers. CONCLUSIONS Autophagy was extensively detected in end-stage heart failure and its progression, resulted in secondary cell death, with occurrence of oncosis and necroptosis exceeding that of apoptosis. Conversely, activation of the RIP1/NF-κB pathway was associated with cell survival.

Cardiac release of urocortin precedes the occurrence of irreversible myocardial damage in the rat heart exposed to ischemia/reperfusion injury.

This study evaluates whether cardiac ischemia induces release of urocortin, before and independently from myocyte cell death. Urocortin levels rose after 5-min ischemia and peaked after 10-min ischemia, when cell death was not detected. However, myocyte apoptosis and/or necrosis occurred following 20- and 30-min ischemia, which paralleled a fall in urocortin levels, suggesting that urocortin expression and release are mainly sustained by metabolically challenged, though still viable myocytes. Hence, since cardiac release of urocortin, unlike that of conventional biomarkers, occurs before and apart from cell death, urocortin levels may be clinically useful in the diagnosis of sublethal myocardial ischemia.

Oral administration of amino acidic supplements improves protein and energy profiles in skeletal muscle of aged rats: elongation of functional performance and acceleration of mitochondrial recovery in adenosine triphosphate after exhaustive exertion.

Sarcopenia is an inevitable age-related degenerative process chiefly characterized by decreased synthesis of muscle proteins and impaired mitochondrial function, leading to progressive loss of muscle mass. Here, we sought to probe whether long-term administration of oral amino acids (AAs) can increase protein and adenosine triphosphate (ATP) content in the gastrocnemius muscle of aged rats, enhancing functional performance. To this end, 6- and 24-month-old male Fisher 344 rats were divided into 3 groups: group A (6-month-old rats) and group B (24-month-old rats) were used as adult and senescent control group, respectively, while group C (24-month-old rats) was used as senescent treated group and underwent 1-month oral treatment with a mixture of mainly essential AAs. Untreated senescent animals exhibited a 30% reduction in total and fractional protein content, as well as a 50% reduction in ATP content and production, compared with adult control rats (p <0.001). Long-term supplementation with mixed AAs significantly improved protein and high-energy phosphate content, as well as the rate of mitochondrial ATP production, conforming their values to those of adult control animals (p <0.001). The improved availability of protein and high-energy substrates in the gastrocnemius muscle of treated aged rats paralleled a significant enhancement in functional performance assessed by swim test, with dramatic elongation of maximal exertion times compared with untreated senescent rats (p <0.001). In line with these findings, we observed that, after 6 hours of rest following exhaustive swimming, the recovery in mitochondrial ATP content was approximately 70% in adult control rats, approximately 60% in senescent control rats, and normalized in treated rats as compared with animals of the same age unexposed to maximal exertion (p <0.001). In conclusion, nutritional supplementation with oral AAs improved protein and energy profiles in the gastrocnemius of treated rats, enhancing functional performance and accelerating high-energy phosphate recovery after exhaustive exertion.

Amino acid supplementation differentially modulates STAT1 and STAT3 activation in the myocardium exposed to ischemia/reperfusion injury.

We have previously demonstrated that the transcription factor STAT1 plays a critical role in promoting apoptotic cell death, whereas the related STAT3 family member may antagonize STAT1 and protect cardiac myocytes from ischemia/reperfusion (I/R) injury. More recently we demonstrated that long-term nutritional supplementation with mixed amino acids (AAs) can enhance myocyte survival by preserving mitochondrial functional capacity during I/R injury. We therefore investigated whether short-term nutritional supplementation with the same AA mixture has any effects on STAT1 or STAT3 activation in the Langendorff perfused rat heart exposed to I/R injury. In Sprague-Dawley rats given a single oral dose of a mixture of mainly essential l-AA (1 g/kg), and exposed, after 6 hours, to 35 minutes of ischemia, followed by 120 minutes of reperfusion, AA supplementation prolonged STAT3 activation/phosphorylation, while STAT1 activation was reduced. Enhanced STAT3 phosphorylation paralleled a reduction in expression of Fas, a known STAT1 target gene and proapoptotic marker that is upregulated after I/R. Moreover, abrogation of STAT3 activation by means of the JAK inhibitor AG490, reduced, but did not abolish, the cardioprotective effects of AA supplementation after I/R. These results show that modulation of the functional balance between STAT3 and STAT1, with preferential activation of prosurvival STAT3 over the proapoptotic STAT1, represents a mechanism by means of which short-term oral supplementation with mixed AAs protects the heart from I/R injury.