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.

451. Is Antibody to Nucleocapsid More Prevalent in Individuals with Severe COVID-19?

Background

Virus-specific antibodies help to understand the prevalence of infections and the course of the immune response. Humans produce antibodies against the spike and nucleocapsid proteins of SARS-COV-2 virus. Patients with COVID-19 who recover from the infections have higher levels of antibodies to spike proteins. Our study aimed to find the levels of antibodies to spike and nucleocapsid proteins in severe COVID-19.

Methods

A single center prospective study was done at Ascension St John Hospital, Detroit, MI. We included COVID-19 cases diagnosed by reverse-transcriptase polymerase-chain-reaction (RT-PCR). Quantitative measurements of plasma or serum antibodies to nucleocapsid and spike proteins were done in hospitalized patients with acute COVID-19. Using the electronic medical record, we collected data on demographic and clinical information.

Results

A total 24 patients were studied. Of which, 15 patients were suffering from severe and critical COVID 19 and 9 patients were suffering from mild to moderate COVID 19. The mean age (standard deviation) of our cohort was 69 ± 10 years and 60% were males. Common comorbid conditions were hypertension, obesity, and type 2 diabetes. We also noted that severe to critical COVID 19 expressed higher level of antibody to nucleocapsid.

Conclusion

These results display the seroconversion in COVID 19 patients. Our study shows antibody level remain high in severe COVID 19 patients but those are against nucleocapsid protein instead of spike protein.

Disclosures

All Authors: No reported disclosures

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.

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.

Cardiovascular Complications of Cancer Therapy: Best Practices in Diagnosis, Prevention, and Management: Part 1

Modern cancer therapy has successfully cured many cancers and converted a terminal illness into a chronic disease. Because cancer patients often have coexisting heart diseases, expert advice from cardiologists will improve clinical outcome. In addition, cancer therapy can also cause myocardial damage, induce endothelial dysfunction, and alter cardiac conduction. Thus, it is important for practicing cardiologists to be knowledgeable about the diagnosis, prevention, and management of the cardiovascular complications of cancer therapy. In this first part of a 2-part review, we will review cancer therapy-induced cardiomyopathy and ischemia. This review is based on a MEDLINE search of published data, published clinical guidelines, and best practices in major cancer centers. With the number of cancer survivors expanding quickly, the time has come for cardiologists to work closely with cancer specialists to prevent and treat cancer therapy-induced cardiovascular complications.

Cardiovascular Complications of Cancer Therapy: Best Practices in Diagnosis, Prevention, and Management: Part 2

In this second part of a 2-part review, we will review cancer or cancer therapy-associated systemic and pulmonary hypertension, QT prolongation, arrhythmias, pericardial disease, and radiation-induced cardiotoxicity. This review is based on a MEDLINE search of published data, published clinical guidelines, and best practices in major cancer centers. Newly developed targeted therapy can exert off-target effects causing hypertension, thromboembolism, QT prolongation, and atrial fibrillation. Radiation therapy often accelerates atherosclerosis. Furthermore, radiation can damage the heart valves, the conduction system, and pericardium, which may take years to manifest clinically. Management of pericardial disease in cancer patients also posed clinical challenges. This review highlights the unique opportunity of caring for cancer patients with heart problems caused by cancer or cancer therapy. It is an invitation to action for cardiologists to become familiar with this emerging subspecialty.

Dual modulation of nitric oxide production in the heart during ischaemia/reperfusion injury and inflammation

Nitric oxide (NO) homeostasis maintained by neuronal/endothelial nitric oxide (NO) synthase (n/eNOS) contributes to regulate cardiac function under physiological conditions. At the early stages of ischaemia, NO homeostasis is disturbed due to Ca2+-dependent e/nNOS activation. In endothelial cells, successive drop in NO concentration may occur due to both uncoupling of eNOS and/or successive inhibition of nNOS catalytic activity mediated by arachidonic acid-induced tyrosine phosphorylation of this enzyme. The reduced NO bioavailability triggers nuclear factor (NF)-kB activation followed by the induction of inducible NOS (iNOS) expression. In cardiomyocytes ischaemia also triggers the induction of iNOS expression during reperfusion. The massive amounts of NO which are subsequently produced following iNOS induction may exert on cardiomyocytes and the other cell types of cells of the heart, such as endothelial and smooth muscle cells, macrophages and neutrophils, opposing effects, either beneficial or toxic. The balance between these two double-faced actions may contribute to the final clinical outcomes, determining the degree of functional adaptation of the heart to ischaemia/reperfusion injury. In the light of this new vision on the critical role played by the cross-talk between n/eNOS and iNOS as well as the non enzymatic NO production by nitrite, we have reason to believe that new pharmacological measurements or experimental interventions, such as ischaemic preconditioning, aimed at counteracting the drop in NO levels beyond the normal range of NO homeostasis during early reperfusion can represent an efficient strategy to reduce the extent of functional impairment and cardiac damage in the heart exposed to ischaemia/reperfusion injury.

Urocortins: take them to heart

The urocortins, together with corticotropin releasing hormone (CRH), have a long evolutionary pedigree. In the brain, CRH largely mediates anxiogenic effects associated with the stress response, while the urocortins are concerned with adaptive and coping behaviour. The urocortins, in particular, are also expressed in peripheral sites, including the heart. Here, they may play an autocrine/paracrine role, since CRH-R2 receptor subtypes, which preferentially bind the urocortins, are also expressed in the heart. Endogenous cardiac urocortin expression is enhanced by ischaemia/reperfusion injury in vitro, and addition of exogenous urocortins reduces cell death caused by ischaemia/reperfusion in vitro, ex vivo and in vivo. In the isolated perfused heart, urocortin improves haemodynamic recovery, and partially prevents the reduction in high energy phosphates following ischaemia/reperfusion. Urocortin-mediated cardioprotection involves several mechanisms, including increased expression of Kir6.1 K(ATP) channels and HSP90, although other as yet poorly understood mechanisms have also been implicated. Moreover, there is early data suggesting that urocortin has beneficial haemodynamic effects in an ovine model of heart failure, and further studies of the value of both endogenous and exogenous urocortins in the compromised heart are clearly needed. In man, there is suggestive, though indirect, data, that urocortin may also provide an endogenous myocyte salvage mechanism against iatrogenic ischaemia/reperfusion injury associated with bypass surgery. These experimental studies suggest that assessment of the clinical use of urocortins as direct and/or cardioplegic therapies in ischaemia/reperfusion, and maybe heart failure, should be actively pursued.

K(ATP) channel gene expression is induced by urocortin and mediates its cardioprotective effect

BACKGROUND

Urocortin is a novel cardioprotective agent that can protect cardiac myocytes from the damaging effects of ischemia/reperfusion both in culture and in the intact heart and is effective when given at reperfusion.

METHODS AND RESULTS

We have analyzed global changes in gene expression in cardiac myocytes after urocortin treatment using gene chip technology. We report that urocortin specifically induces enhanced expression of the Kir 6.1 cardiac potassium channel subunit. On the basis of this finding, we showed that the cardioprotective effect of urocortin both in isolated cardiac cells and in the intact heart is specifically blocked by both generalized and mitochondrial-specific K(ATP) channel blockers, whereas the cardioprotective effect of cardiotrophin-1 is unaffected. Conversely, inhibiting the Kir 6.1 channel subunit greatly enhances cardiac cell death after ischemia.

CONCLUSIONS

This is, to our knowledge, the first report of the altered expression of a K(ATP) channel subunit induced by a cardioprotective agent and demonstrates that K(ATP) channel opening is essential for the effect of this novel cardioprotective agent.

Apoptosis of endothelial cells precedes myocyte cell apoptosis in ischemia/reperfusion injury

BACKGROUND

Apoptosis contributes to cell loss after ischemia/reperfusion injury in the heart. This study describes the time course and level of apoptosis in different cell types in the intact heart during ischemia/reperfusion injury.

METHODS AND RESULTS

Isolated Langendorff-perfused rat hearts were subjected to perfusion alone (control) or to 35 minutes of regional ischemia, either alone or followed by 5, 60, or 120 minutes of reperfusion. Sections were stained by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and propidium iodide and with anti-von Willebrand factor, anti-desmin, or anti-active caspase 3 antibodies; they were then visualized by confocal microscopy. Sections were also examined by electron microscopy. No TUNEL-positive cells were seen in control hearts or hearts exposed to ischemia alone. Early in reperfusion, TUNEL staining was colocalized with endothelial cells from small coronary vessels. Endothelial apoptosis peaked at 1 hour of reperfusion and, at this time, there was clear perivascular localization of apoptotic cardiac myocytes, whose number was inversely proportional to their distance from a positive vessel. After 2 hours of reperfusion, apoptotic cardiac myocytes assumed a more homogeneous distribution. Active caspase 3 labeling was seen independent of DNA fragmentation during ischemia alone, but it colocalized with TUNEL staining over the 3 time points of reperfusion. Immunocytochemical findings were confirmed by electron microscopy and Western blotting.

CONCLUSIONS

In the very early stages of reperfusion, apoptosis is first seen in the endothelial cells from small coronary vessels. The radial spread of apoptosis to surrounding cardiac myocytes suggests that reperfusion induces the release of soluble pro-apoptotic mediators from endothelial cells that promote myocyte apoptosis.

Impact of highly active antiretroviral therapy in HIV-positive patients with cardiac involvement

OBJECTIVES

Cardiac involvement is frequently observed in HIV-infected patients, especially in those in the late stage of the disease. This study was designed to evaluate the impact of highly active antiretroviral therapy (HAART) in patients with cardiac involvement.

METHODS

A retrospective study of 1042 patients admitted to a Division of Infectious Diseases between 1989 and 1998. During the period 1989-1995, 544 patients were treated with nucleoside reverse transcriptase inhibitors (NRTI), whereas 498 patients were treated with HAART during the period 1996-1998.

RESULTS

Cardiac involvement, including arrhythmias, pericarditis, ischaemia, dilated cardiomyopathy, endocarditis, pulmonary hypertension, and myocarditis were observed in 282 of 544 (51.8%) patients treated with NRTI, compared with 93 of 498 (18.6%) patients with HAART (P < 0.0001).

CONCLUSIONS

HAART has significantly decreased the incidence of cardiac involvement, especially pericarditis, arrhythmias, and dilated cardiomyopathy.