Pathogenic Potential of Hic1-Expressing Cardiac Stromal Progenitors

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OMA1-mediated integrated stress response protects against ferroptosis in mitochondrial cardiomyopathy

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2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.     

Synthesis and properties of a new conformational antigen which models an extracellular region of β1-adrenoreceptor

Two fragments corresponding to the 125–133 and 206–218 sequences of a molecule of the β1-adrenoreceptor (autoantibodies to this protein are often found in patients with dilated cardiomyopathy) were synthesized by the solid phase method with the use of Fmoc technology. Two new conformational antigens were prepared by directed (regioselective) and undirected (spontaneous) formation of intramolecular and intermolecular disulfide bridges between the corresponding cysteine residues of the synthesized peptides. One of these antigens consisted of a mixture of disulfide isomers, and another antigen was an isomer with a natural arrangement of S-S bridges. Immunosorbents were obtained by immobilization of the synthesizes antigens on the bromocyanogen-activated sepharose and applied to the removal of autoantibodies in a β1-adrenoreceptor from the blood plasma of patients. We demonstrated that the sorbents on the basis of the conformational antigens were more effective in comparison with those containing linear peptide precursors.     

Depressed antioxidant defense in rat heart in experimental magnesium deficiency implications for the pathogenesis of myocardial lesions

Magnesium (Mg) deficiency has been shown to produce myocardial lesions in different experimental models. Based on several lines of evidence, it has been proposed that oxidative injury to the cardiac muscle may explain the pathobiology of such lesions. In pursuance of this postulation, the present study examined the effect of dietary deficiency of Mg on the activity of the antioxidant enzymes, Superoxide dismutase (SOD) and catalase, in rat heart. This article reports a significant lowering of the activity of both these enzymes in the cardiac tissue in Mg-deficient rats. Since depressed antioxidant defense in the heart may enhance myocardial susceptibility to oxidative injury, the observation is of possible relevance to the pathogenesis of cardiac lesions in Mg deficiency.     

Studies on the relations of selenium and Keshan disease

Keshan disease is an endemic cardiomyopathy of unknown cause in The People’s Republic of China that occurs most frequently in children under 15 years of age and women of child-bearing age. Studies of children 1–9 years old in Mianing County of Sichuan Province have indicated that Keshan disease is a selenium responsive condition. Incidence rates of 9.5–13.5/1000 in 1974–1975 were reduced to 1–2/1000 in children treated with a tablet weekly of 0.5–1 mg sodium selenite. During 1974–1977, only 21 cases of the disease occurred in 36,603 treated children, compared with 106 cases in 9430 untreated children, of whom 53 died and 5 still have insufficient heart function. Occurrence of the disease was invariably associated with a lower selenium content of cereals, and of hair (less than 0.12 ppm Se) in residents from affected, compared with non-affected, areas. The dose relationship between selenium and regional characteristics of Keshan disease suggests that it is probably a biogeochemical disease; other etiological factors have also been considered.     

Novel mutation in N-terminal fragment of ryanodine receptor 2 causing catecholaminergic polymorphic ventricular tachycardia

CPVT is a rare inherited arrhythmogenic disorder characterized by bidirectional, polymorphic ventricular arrhythmias triggered by catecholamines released during exercise, stress, or sudden emotion in individuals with a normal resting electrocardiogram and structurally normal heart. Mutations in the ryanodine receptor 2 gene are the most common known etiology of this disorder. The c.1195A > G(p.Met399Val) variant in Exon 14 of RyR2 is currently classified as a Variant of Uncertain Significance. We present a case of CPVT caused by this novel disease-causing RyR2 variant and discuss its pathophysiology. The role of SSRIs in treating patients with CPVT unresponsive to mainstream therapies is also highlighted.