On the mechanism of the antiarrhythmic action of fabomotizole hydrochloride in alcoholic cardiomyopathy

It is known that the alcoholic cardiomyopathy (ACMP) is the main reason for lethality from chronic alcoholism. For ACMP the risk of development of malignant violations of a heart rhythm which result approximately at 40% of such patients is sudden heart death is extremely high. Materials and methods. Experiments were made on the ACMP translational model developed by us which is formed at rats by the end of the 24th week of compulsory reception of 10 % of ethanol solution. For studying the mechanisms which are the responsible of antiarrhythmic action of a fabomotizole dihydrochloride used a complex of morphohistological, electrophysiological and molecular researches. Results. It is shown that against the background of systematic therapy fabomotizole dihydrochloride (15 mg/kg, i.p.) daily within 28 days after 24 weeks of alcoholization, in comparison with alcoholized control the fat dystrophy of a myocardium significantly decreases and the threshold of electric fibrillation of heart ventricles is restored. According to results of molecular researches, a fabomotizole dihydrochloride significantly suppresses revealed in control alkoholized animals the abnormal mRNA expression of key receptor genes and proteins responsible for maintenance in cardiomyocytes of a homeostasis of ions of Ca++ and regulation of their rhythmic activity: regulatory proteins Epac1 (p = 0.021), Epac2 (p = 0.018), CaM (p = 0.00001) and also RyR2 (p = 0.031), IP3R2 (p = 0.006) receptors. Conclusion. The obtained results suggest that antiarrhythmic action of a fabomotizole dihydrochloride in the conditions of ACMP is connected with its ability to suppress abnormal activity of regulatory proteins Epac2 and RyR2, IP3R2 receptors.

Natriuretic peptides and Forkhead O transcription factors act in a cooperative manner to promote cardiomyocyte cell cycle re-entry in the postnatal mouse heart

Background Cardiomyocytes proliferate rapidly during fetal life but lose their ability of proliferation soon after birth. However, before terminal withdrawal from the cell cycle, cardiomyocytes undergo another round of cell cycle during early postnatal life in mice. While a transient wave of increased DNA synthesis in cardiomyocyte has been observed in postnatal mouse hearts, the molecular mechanisms describing cardiomyocyte cell cycle re-entry remain poorly understood. Atrial and B-type natriuretic peptides (ANP and BNP) are abundantly expressed in embryonic heart ventricles. After birth, the expression of both genes is strongly reduced in the ventricular myocardium. Forkhead O (FOXO) transcription factors are expressed in both embryonic and postnatal heart ventricles. Their transcriptional activity negatively affects cardiomyocyte proliferation. Upon phosphorylation, FOXO is translocated to the cytoplasm and is transcriptionally inactive. Despite these important findings, it remains largely unknown whether natriuretic peptides and FOXO cooperatively play a role in regulating cardiomyocyte cell cycle activity during early postnatal life. Results We observed that the expression of ANP and BNP and the level of phosphorylated FOXO were transiently increased in the postnatal mouse heart ventricles, which coincided with the burst of cardiomyocyte cell cycle re-entry during early postnatal life in mice. Cell culture studies showed that ANP/BNP signaling and FOXO cooperatively promoted cell cycle activity in neonatal mouse cardiomyocytes. The enhanced cell cycle activity observed in combined treatment of ANP/BNP and dominant-negative FOXO (DN-FOXO), which can bind FOXO recognition sites on DNA but cannot activate transcription, was primarily mediated through natriuretic peptide receptor 3 (Npr3). In mice, simultaneous application of ANP and DN-FOXO in postnatal hearts reactivated cell cycle in cardiomyocytes, resulting in reduced scar formation after experimental myocardial infarction. Conclusions Our data demonstrate the cooperative effects of natriuretic peptide and DN-FOXO on promoting cardiomyocyte cell cycle activity and mouse cardiac repair and regeneration after injury.

BRAIN NATRIURETIC PEPTIDE (BNP) SEBAGAI BIOMARKER GAGAL JANTUNG KONGESTIF

Brain Natriuretic Peptide (BNP) is mainly secreted by the heart ventricles and acts as antagonist to Renin-Angiotensin-Aldosterone. BNP is secreted as pre-proBNP which is broken down into BNP and proBNP in circulation. The BNP examination is done by measuring the levels of BNP or N-Terminal-proBNP depending on the method and the manufacturer. Increased levels of BNP and NT-proBNP indicate heart failure so that BNP and NT-proBNP are considered markers of heart failure. This examination is also indicated to help establish the diagnosis, monitoring, and prognosis of heart failure. Natriuretic peptide examination can be done by several methods such as radioimmunoassay (RIA), Enzyme immunoassay (EIA), Fluorescence immunoassay (FIA), and Sandwich Electro Chemiluminescence Immuno Assay (Sandwich ECLIA).