Acute Effect of Selective Chemical Inactivation of Sympathetic or Parasympathetic Atrial Ganglionated Plexus Structures on Atrial Fibrillation Inducibility in Pigs.

We studied the role of both parts of the autonomic intracardiac nervous system in the pathogenesis of atrial fibrillation (AF). In 12 pigs weighing 39±3 kg, AF was induced by burst stimulation. Chemical inactivation of intrinsic cardiac neurons within the right atria was performed by transendocardial injections of liposomal neuromodulators into the dorsal part of the right atrial wall. Sympathetic and parasympathetic terminals were inactivated with 6-hydroxydopamine (6-OHDA, n=6) and ethylcholine aziridinium ion (AF64A, n=6), respectively. Neuromodulators were encapsulated in liposomes (LS) with diameters of 310±50 nm for OHDA and 290±50 nm for AF64A. LS-6-OHDA and LS-AF64A were injected into the ganglionated plexuses after measuring the baseline effective refractory period and assessing myocardial resistance to AF. These measurements were repeated 90 min after the injections. The optimal doses were 0.2 mg/kg for LS-6-OHDA and 0.4 mg/kg for LS-AF64A (in 4 ml of suspension). Immediately after injections of liposomal neuromodulators, almost all pigs showed an increase in HR, and a short-term BP elevation was observed in the LS-AF64A group. At the end of the experiment, similar decrease in the effective refractory period and similar increase in the resistance to AF were observed in all animals. Thus, selective chemical inactivation of cholinergic and adrenergic terminals of the intracardiac nervous system with liposomal neuromodulators increased the resistance to AF in an acute experiment. However, the short observation period does not allow making a definite conclusion about the role of the autonomic nervous system in the pathogenesis of AF, which requires verification of the obtained data in a chronic experiment.

[Reverse remodelling of the heart after atrial fibrillation ablation in patients with heart failure with reduced ejection fraction].

AIM: To evaluate the effect of atrial fibrillation (AF) catheter ablation (CA) on long-term freedom from AF and left heart reverse remodeling in patients with heart failure with reduced ejection fraction (HFrEF). METHODS: There were 47 patients (mean age 53.3 ± 10 years, 39 males) enrolled into single-center observational study, with left ventricular ejection fraction (LVEF) <40 %. Patients underwent CA for AF refractory to antiarrhythmic drugs. Baseline clinical data and diagnostic tests results were obtained during personal visits and / or via secure telemedical services. Personal contact with evaluation of recurrence of AF and echocardiographic values was performed with 30 (64 %) patients. RESULTS: Paroxysmal AF was present in 12 (40 %) patients, persistent - in 18 (60 %). During mean follow-up of 3 years (0.5-6 years) redo ablation was performed in 9 patients (30 %) with average number of 1.3 procedures per patient. At 6 months 24 (80 %) patients were free from AF, at last follow-up - 16 (53 %). The mean time to first recurrence following CA was 15.6±13.3 months. Follow-up echocardiography revealed significant LVEF improvement (р<0,0001), reduction of left atrium size (р<0,0001), left ventricle end-diastolic volume (р<0,002) and left ventricle endsystolic volume (p<0,0001) and mitral regurgitation (р=0,001). CONCLUSION: AF CA in patients with HFrEF is associated with improvement in systolic function and left heart reverse remodeling. Durable long-term antiarrhythmic effect often requires repeated procedures.

Polyarginine Peptides As a New Class of Ligands of Nicotinic Acetylcholine Receptors.

Arginine-containing peptides R3, R8, and R16 were obtained by solid-phase peptide synthesis, and their binding to nicotinic acetylcholine receptors (nAChRs) of muscle and neuronal (α7) types was studied by competitive radioligand assay with the use of 125I-α-bungarotoxin. The resulting peptides exhibited a significantly greater binding activity with respect to the muscle-type nAChRs than to the α7 receptor. Thus, we have discovered a new class of nAChR ligands. The affinity of the synthesized oligoarginines for nAChR depended on the number of amino acid residues in the chain. The highest affinity was exhibited by the R16 peptide, which contained 16 arginine residues.

The First Recombinant Viper Three-Finger Toxins: Inhibition of Muscle and Neuronal Nicotinic Acetylcholine Receptors.

Genes encoding two three-finger toxins TFT-AF and TFT-VN, nucleotide sequences of which were earlier determined by cloning cDNA from venom glands of vipers Azemiops feae and Vipera nikolskii, respectively, were expressed for the first time in E. coli cells. The biological activity of these toxins was studied by electrophysiological techniques, calcium imaging, and radioligand analysis. It was shown for the first time that viper three-finger toxins are antagonists of nicotinic acetylcholine receptors of neuronal and muscle type.

Arginine derivatives of dicarboxylic acids from the parotid gland secretions of common toad Bufo bufo-New agonists of ionotropic γ-aminobutyric acid receptors.

Compounds activating γ-aminobutyric acid type A receptor were isolated from the toad Bufo bufo venom as a result of chromatographic separation. Analysis of the structure of these compounds by mass spectrometry and nuclear magnetic resonance showed that they are arginine derivatives of dicarboxylic acids and represent suberylarginine, pimeloylarginine, and adipoylarginine.

N-methyl serotonin analogues from the Bufo bufo toad venom interact efficiently with the α7 nicotinic acetylcholine receptors.

Two low-molecular-weight compounds were isolated from the parotid gland secret of the toad Bufo bufo, which by absorption spectra and HPLC-MS/MS chromatography data correspond to di- and trimethyl derivatives of serotonin (5-hydorxytryptamine): bufotenine (confirmed by counter synthesis) and bufotenidine (5-HTQ). In experiments on competitive radioligand binding, these compounds showed a higher affinity and selectivity for neuronal α7 nicotinic acetylcholine receptors compared with the muscular cholinergic receptors. The most efficient compound in terms of binding value was bufotenine, the efficiency of 5-HTQ was an order of magnitude lower, and the minimal activity was exhibited by serotonin.

[Noninvasive Electrophysiological Mapping in Patients With Complete Left Bundle Branch Block and Different Modes of Biventricular Pacing].

OBJECTIVE: to investigate possibilities of noninvasive electrophysiological mapping (NEM) during biventricular (BiV) pacing and to compare the results with data of 12 lead ECG and tissue Doppler echocardiography (TDI). MATERIAL AND METHODS: The study included 25 patients with complete left bundle branch block (LBBB) and implanted cardiac resynchronization therapy (CRT) system. Twenty-two patients were CRT responders, three other patients did not demonstrate a clear effect. NEM was performed with "Amycard 01C EP LAB" system and multi slice computed tomography. RESULTS: Qualitative analysis of isochronous maps at NEM showed that the most homogenous color coding of the left ventricle (LV) may correspond to the optimal BiV pacing mode. A statistically significant positive correlation between the width of the QRS complex during a set BiV pacing mode and the standard activation deviation time, measured at NEM, for 12 segments (SD12) LV (r= 0,88, p<0,0001) was observed. With the minimum value of SD12 and biventricular QRS width at the same time, three patients had intraventricular dyssynchrony. A comparative analysis of NEM and TDI methods in terms of interventricular dyssynchrony (IVD) at LBBB revealed statistically significant positive correlation (r=0,58, p=0,005). CONCLUSION: These data show that both minimal values of QRS and SD12 at BiV pacing are not accompanied by the effect of CRT in all patients. The lack of response from this type of therapy is associated with a non-optimal position of the LV electrode. Qualitative assessment of isochronous maps at NEM demonstrates intraventricular dyssynchrony and can help in selecting the optimal mode of BiV pacing.

[Interventional treatment in patients with myocarditis: Pro and Contra].

AIM: Ventricular tachyarrhythmias (VTs) are often encountered in patients with inflammatory heart diseases. VT can become lifethreatening in patients with myocarditis, and the management may vary in different types of myocarditis. Purpose of the study is to describe VT characteristics in patients with verified myocarditis, and to evaluate the efficacy and safety of VT management, when tailored to the type of myocarditis. MATERIALS AND METHODS: Study population comprised: 56 patients with morphologically verified myocarditis; 18 patients with primary cardiomyopathy (control group). All patients underwent full clinical evaluation, endomyocardial biopsy (including immunohistochemical analysis). Forty (54 %) patients underwent radiofrequency catheter ablation of VT. An implantable cardioverter-defibrillator (ICD) was inserted in 17 patients. RESULTS: There was no statistically significant difference between myocarditis and primary cardiomyopathy groups by demographic and echocardiographic data. In myocarditis group, nonsustained VT and/or frequent premature ventricular beats were seen in 59 % of patients; sustained VT in 12,5 % subjects, 1 patient had a history of ventricular fibrillation. VT ablation was associated with a significant decrease in VT recurrence (p=0,0009) during the follow-up period. Active myocarditis was associated with a higher VT recurrence rate (67 % in active vs. 19 % in borderline myocarditis). Among patients with ICD implantation, only one subject (with active myocarditis at admission) had life-threatening ventricular arrhythmia. CONCLUSION: In this selected group of patients with verified myocarditis and clinically significant VTs, catheter ablation seems at least partly effective. Patients with borderline myocarditis and symptomatic VTs may benefit from ablation. Therefore, morphological diagnostic of myocarditis can be a key point in choice of treatment.

[Autoimmunity and Prognosis of Patients With Morphologically Documented Myocarditis].

AIM: to assess clinical and prognostic value of circulating cardiospecific autoantibodies (AAB) and CD4+ T-regulatory cells in patients with myocarditis. MATERIAL AND METHODS: We included into this study 47 patients with lymphocytic myocarditis verified by analysis of histological and immunohistochemical data. Comparison group consisted of 30 practically healthy persons. Content of marker cardiotropic AAT were measured with the help of standardized immune enzyme test-systems. Number of circulating CD4+CD25+ and CD4+CD25+FoxP3+ T-lymphocytes were evaluated by flow cytometry. RESULTS: Among factors determining prognosis of patients with lymphocytic myocarditis factors of key significance were the presence of clinically overt heart failure at the disease debut, and degree of reduction of left ventricular ejection fraction. Distinctive feature of active myocarditis was elevation of titer of AABs to sarcomeric, cytoskeleton, and cytoplasmic proteins of cardiomyocytes, as well as elevated level of AABs to various epitopes of adenine nucleotide translocator. Elevated level of AAB to 1-adrenoreceptors was an independent predictor of unfavorable outcome in patients with lymphocytic myocarditis. Increased population of circulating CD4+CD25+ T-regulatory cells was as sociated with elevated concentration of of natriuretic peptide. CONCLUSION: Abnormalities in the system of autoimmunity play key role not only in pathogenesis but also in prognosis of inflammatory myocardial diseases. Changes of profile of circulating cardiospecific AABs and T-regulatory cells can bear a protective function.

Molecular effects of cardiac contractility modulation in patients with heart failure of ischemic aetiology uncovered by transcriptome analysis.

Cardiac contractility modulation (CCM) is based on electrical stimulation of the heart without alteration of action potential and mechanical activation, the data on its fundamental molecular mechanisms are limited. Here we demonstrate clinical and physiological effect of 12 months CCM in 29 patients along with transcriptomic molecular data. Based on the CCM effect the patients were divided into two groups: responders (n = 13) and non-responders (n = 16). RNA-seq data were collected for 6 patients before and after CCM including 3 responders and 3 non-responders. The overall effect of CCM on gene expression was mainly provided by samples from the responder group and included the upregulation of the genes involved in the maintenance of proteostasis and mitochondrial structure and function. Using pathway enrichment analysis, we found that baseline myocardial tissue samples from responder group were characterized by upregulation of mitochondrial matrix-related genes, Z disc-protein encoding genes and muscle contraction-related genes. In summary, twelve months of ССM led to changes in signaling pathways associated with cellular respiration, apoptosis, and autophagy. The pattern of myocardial remodeling after CCM is associated with initial expression level of myocardial contractile proteins, adaptation reserves associated with mitochondria and low expression level of inflammatory molecules.

[Intravital and postmortem morphological studies and magnetic resonance imaging of arrhythmogenic right ventricular dysplasia].

The authors conducted histological, immunohistochemical, and morphometric studies of 47 endomyocardial biopsies and 33 hearts with a high morphological criterion for the diagnosis of arrhythmogenic right ventricular dysplasia after F.I. Marcus et al. (2010), as well as intravital and postmortem cardiac magnetic resonance imaging (MRI). The average residual cardiomyocyte area was 39.7 +/- 12.8%, and the average cardiomyocyte diameter was 10.4 +/- 1.5 microm. Muscle fiber atrophy, lipomatosis, and fibrosis in the right ventricle were detected in all cases, myocarditis in 44%, mitral valve prolapse in 42%, and muscle fiber dyscomplexation in the right ventricular in 33%. The most informative signs for the diagnosis of arrhythmogenic right ventricular dysplasia using MRI are right ventricular contraction dyssynchrony and those using a morphological study are a residual cardiomyocyte area and muscle fiber atrophy in the right ventricle. A decrease in or focal absence of gamma-catenin expression in the muscle fibers was observed only in 60% of the patients.

[First experience of the study "Intramyocardial Multiple Precision Administration of Mononuclear Bone Marrow Cells in the Treatment of Myocardial Ischemia"].

Study aim - to elucidate possibilities of the use of precision administration of mononuclear bone marrow cells (MBMC) for the treatment of myocardial ischemia and heart failure. "Intramyocardial Multiple Precision Administration of Mononuclear Bone Marrow Cells in the Treatment of Myocardial Ischemia" was a double blind randomized placebo controlled study in which we included patients more or equal 6 months after Q-wave myocardial infarction with systolic myocardial dysfunction (ejection fraction <35%), not requiring myocardial revascularization, receiving stable optimal medical therapy for more or equal 8 weeks, and with implanted cardioverter-defibrillator. Transplantation of MBMC was guided by fluoroscopy and tridimensional NOGA XP Cardiac Navigation System. For assessment of efficacy of the method we used surrogate end points: decrease of number of fixed perfusion defects according to SPECT data and improvement of regional myocardial contractility according to data of echocardiography. Results of dynamic observation of the first experience of MBMC administration are presented in this paper.

[Cryoballoon ablation for pulmonary vein isolation to treat atrial fibrillation: first experience in Russian Federation].

Cryoballon ablation (CBA) for pulmonary vein (PV) isolation is a new method for catheter-based treatment of patients with atrial fibrillation (AF). The purpose of our work is to describe the CBA technique and to report its short-term results. Methods. CBA was performed in 12 patients (8 men; age 53.1+/-5.7 years) with highly symptomatic drug-refractory AF. Paroxysmal AF was present in 11 and persistent AF - in 1 patient. CBA procedure was carried out under general anesthesia with intubation in 6 and under light sedation in 6 patients. After transseptal access and direct PV angiography, 28 mm-cryoballoon was introduced into the left atrium, and more or equal 2 cryoapplications were delivered to each PV, once good PV occlusion was obtained. PV isolation was verified utilizing a circular mapping catheter. Arrhythmia recurrences were monitored every 3 months after ablation using 24-hour Holter, and additional ECG registrations. Holter monitoring was also performed in a case of symptoms. Results. Complete electrical PV isolation was achieved by only cryoballoon ablation in 11 patients, and additional cryocatheter touch-up ablation was required in left PVs in 1 patient. Total procedure time was 203.1+/-34.2 min, fluoroscopy time - 50.5+/-14.0 min. There were no complications. During a mean follow-up period of 136.8+/-59.8 days 9 (75%) patients were free from arrhythmia recurrence after a single procedure. Redo ablation was required in 1 patient, in whom electrical reconnection to all PVs was documented. Conclusion. CBA is a novel promising technique for treatment of patients with AF, and now is available in Russian Federation. The method standardizes and facilitates interventional AF treatment with acute isolation of 96% PVs. The short-term follow-up shows freedom from atrial tachyarrhythmias in 75% of patients.

[Choice of the surgical approach for implantation of a left ventricular lead by the data of prolonged coronaroangiography].

Effectiveness of prolonged coronarography was assessed for investigation of venous heart anatomy with reference to etiology of the disease and heart chamber sizes. It was shown that lesions of the coronary arteries and morphometrical indices of the heart did not influence the heart venous anatomy. A detailed analysis of patients with ischemic heart disease and anamnesis of myocardial infarction has revealed the absence of the heart vein in the zone of old myocardial infarction. At the preoperative stage the placement of a cardiac resyncronising device the integration of data of EchoKG, prolonged coronaroangiography and others allows determination of the possible surgical method of placing the lead to the left ventricle of the heart. The algorithm of the method of decision on the placement of the left ventricular lead has been developed, investigated and introduced into clinical practice.

Expression of mitochondrial uncoupling protein UCP2 in the brain of rats after hippocampal injury inflicted by kainic acid.

The expression of mitochondrial protein UCP2 and cytochrome C-oxidase subunit III genes in the hippocampus and prefrontal cortex was evaluated by real-time PCR 3 and 7 days after microinjection of kainic acid into the dorsal hippocampus. In contrast to cytochrome C-oxidase subunit III mRNA, the level of UCP2 mRNA in the hippocampus increased 1 week after microinjection of kainic acid. The expression of both genes in the prefrontal cortex did not differ from the control. Presumably, activation of UCP2 synthesis in hippocampal injury indicates the neuroprotective effects of this protein.

Expression of mGluR5 and synaptophysin genes after injury to the dorsal Hippocampus, inflicted by cainic acid.

The expression of synaptophysin (vesicular protein) and mGluR5 (metabotropic glutamate receptor) genes was studied 3, 7, and 20 days after cainic acid injury of the dorsal hippocampal area in Wistar rats. The expression of both genes was characteristically reduced in the hippocampus. Twenty days after the exposure the expression of mGluR5 in this brain area reached the control level, while synaptophysin expression remained low. An opposite trend was observed in the frontal cortex: synaptophysin expression 20 days after exposure did not differ from the control, while mGluR5 expression was reduced. The peculiar time course of both genes' expression in the hippocampus and frontal cortex indicates the involvement of the frontal cortex in mechanisms of functional recovery after hippocampal injuries.

[Effect of intrahippocampal kainic acid on the behavior of rats and functional state of mitochondria in brain structures].

Cognitive processes and functional state of mitochondria in brain structures of Wistar rats were studied after intrahippocampal injection of kainic acid, an agonist of glutamate receptors. A single administration of 0.25 microg kainic acid into the dorsal part of the left and right hippocampi affected task retrieval and decreased inhibition of unrewarded responses. The injection of 0.75 microg kainic acid induced recurrent seizures and completely disorganized animal behavior. The functional state of mitochondria, as an important marker of excitotoxicity, was studied after intrahippocampal injections of kainic acid in the same doses. Kainic acid at 0.25 microg proved to activate the oxidative phosphorylation in hippocampal mitochondria. A higher (epileptogenic) dose of kainic acid inhibited mitochondrial respiration in the frontal cortex, but had an insignificant effect on mitochondrial respiration in the hippocampus. The disturbed interaction between the hippocampal system and frontal cortex after kainic acid administration can be the main factor of the revealed cognitive dysfunctions.

[Prognosis of the severity of acute pancreatitis by the neural network method].

For prognozing the character of the development of acute pancreatitis a neural network of the direct spread of the signal was developed with 15 inlets, 5 neurons of the latent layer and two outlets. The network was trained with the help of an algorithm of an inverse spread of the error. The sensitivity of the produced prognostic model was 100%, specificity at admission--70%, on the first day--80%, on the second and third day--90%. Before the moment of hospitalization 57 patients were observed during 72 hours. The diagnosis was confirmed in all cases by the methods of computed tomography with contrast amplification.

Photoreceptor coupling and boundary detection.

Electrical coupling between photoreceptors results in the extensive spreading of output potentials along the syncytium of photoreceptor terminals. This smoothing of output potentials seems to make spatial resolution worse. However, the photoreceptor noise that is considered to be non-correlated both in space and time is smoothed to the greater extent than the correlated potential difference across the boundaries between areas of different brightness. This improves the signal-to-noise ratio more for more extended boundaries and favours lowering the threshold so that they can be detected more easily during the subsequent processing. The results have a striking parallel with a well known dependence of contrast threshold on stimulus size as measured psychophysically.