Several experimental studies have recently demonstrated that temporary autonomic block using botulinum toxin (BoNT/A1) might be a novel option for the treatment of atrial fibrillation. However, the assessment of antiarrhythmic properties of BoNT has so far been limited, relying exclusively on vagal stimulation and rapid atrial pacing models. The present study examined the antiarrhythmic effect of specially formulated BoNT/A1-chitosan nanoparticles (BTN) in calcium chloride-, barium chloride- and electrically induced arrhythmia rat models. BTN enhanced the effect of BoNT/A1. Subepicardial injection of BTN resulted in a significant antiarrhythmic effect in investigated rat models. BTN formulation antagonizes arrhythmia induced by the activation of Ca, K and Na channels.

Pigs as laboratory animals are used in preclinical studies aimed at developing medical devices for cardiac surgery. The anatomy of the cardiovascular system of these animals has been well studied and acknowledged as suitable for use and the testing of new cardiovascular devices developed for humans. However, there are no morphometric characteristics of the aortic root and thoraco-abdominal part of porcine aorta. This can lead to difficulties in experimental surgery and even result in the death of experimental animals due to the mismatch in the size of the implantable devices. Thus, such information is essential to enhance the efficiency of surgical technologies used for eliminating aortic pathologies in their various sections. The purpose of our research is to study the anatomy of the aorta in mini pigs and to assess whether the size, age, and sex of the animals affect the size of the main structures in their aortas. In addition, we attempted to compare the results obtained by transesophageal echocardiography (TEE) and angiography. We studied 28 laboratory mini pigs, dividing them into three groups by body weight (40–70 kg, 71–90 kg, and 90 kg). We did not find any relationship between the external somatometric characteristics of the animals and the size of their aortas. Animals have individual anatomical variability in their cardiovascular systems, which means that they need to be examined in terms of preoperative planning by any available method—echocardiography, angiography, or multispiral computed tomography (CT).

The aim of the study is to assess the availability of this animal model for preclinical testing of implantable cardiovascular devices by studying numerical anatomical and functional characteristics of the ovine heart and to establish their differences from those of the human heart. The study was performed on 17 healthy crossbred Romanov sheep weighing 20-29 kg in group 1 (n=7) and 30-43 kg in group 2 (n=10). All animals underwent echocardiography examination on the Philips CX-50 apparatus (revision 3.1.2; Philips, Netherlands) with a sector-phased S5-1 sensor from the right parasternal projection (long and short axis) to determine the heart rate, right ventricular wall thickness in diastole, right and left ventricular end-diastolic dimensions (RV EDD and LV EDD), left ventricular end-systolic dimension (LV ESD), interventricular septum (IVS) thickness in systole and diastole, left ventricular posterior wall thickness in systole and diastole.Functional parameters of the left ventricle (left ventricle end-systolic and end-diastolic volumes (LV ESV and LV EDV), ejection fraction and shortening fraction) were calculated using the modified Simpson method built into the echocardiography software. The diameter of the mitral annulus and the characteristics of the aortic root were also measured: the diameters of the aortic valve, Valsalva sinuses, and sinotubular junction, as well as the height of the aortic root from the fibrous ring to the line of the sinotubular junction. Direct measurements of the ascending aorta and pulmonary artery diameters, intercommissural distances, and the height of the aortic valve leaflets were performed after autopsy. A number of anatomical and functional parameters of the sheep heart such as ejection fraction, myocardium thickness, LV EDD and LV ESD, aorta, and pulmonary artery diameters, have been established to be close to those of the human heart. At the same time, LV EDV and LV ESV of the sheep are significantly lower than in humans, even in relation to the body surface area, and the average mitral valve diameter is larger. Despite the same diameters of the aortic valve, Valsalva sinuses, and sinotubular junction, the structures of the ovine and human aortic roots are different: the sheep root features a smaller height and intercommissural distances of the cusps. In addition, some differences were found in the arrangement of the cusps in relation to the valve axis: the intercommissural distance of the right coronary leaflet was almost 2 times greater than the similar indicator of the left coronary leaflet.Most anatomical and functional parameters have not shown any correlation with the animals' body weight. Only in group 2, a significant positive correlation between body weight and the height of the aortic valve leaflets was found. The anatomical and functional characteristics of the sheep heart are close but not identical to human hearts. The sheep is a valid experimental model for preclinical testing of implantable cardiovascular devices, but a successful experiment requires careful screening of animals with echocardiographic assessment of the target zone parameters and selection of the appropriate device size.

Objective: To evaluate the performance and short-term capacity of the diepoxy-treated bovine jugular vein conduit in large animals during 6-month follow-up.Methods: Thirteen diepoxy-treated bovine jugular vein conduits were implanted into the pulmonary artery of young mini-pigs. During the follow-up, graft function was tested using transesophageal echocardiography. The animals were withdrawn at 6 months, and the explanted conduits were assessed histologically.Results: All the conduits were successfully implanted without any surgical complications. All the animals survived throughout the follow-up. By the end of the follow-up period, the pressure gradient increased on five animals’ conduits including one case of mismatch between the conduit and the native pulmonary artery, two cases of distal stenosis, and two case of endocarditis. No significant increase in valve regurgitation or conduit thrombosis was observed during the follow-up. In conduits without dysfunction, the structure of the walls and leaflets was intact. A thin fibrous tissue covered the conduit inner wall with complete surface endothelialization. Neither signs of degeneration or calcification nor inflammatory cells were found in the conduit wall or leaflets. Neointima proliferation without calcium deposits was observed in two distally stenosed conduits. Inflammatory cells consisting of multinucleated macrophages, lymphocytes, and histiocytes were found in the adventitia. There were no inflammatory cells in the media or intima, and the leaflets showed no changes.Conclusion: Diepoxy-treated bovine jugular vein demonstrated acceptable performance, good endothelialization, and low tendency to thrombosis and calcium accumulation in the wall and leaflets. Received 31 October 2022. Revised 25 November 2022. Accepted 28 November 2022. Funding: The study was supported by Russian Science Foundation (grant No. 22-25-20102). Conflict of interest: The authors declare no conflict of interest. Contribution of the authorsConception and study design: N.R. Nichay, I.Yu. Zhuravleva, A.V. Bogachev-ProkophievData collection and analysis: N.R. Nichay, Yu.Yu. Kulyabin, I.S. Zykov, E.V. Boyarkin, O.Yu. Malakhova, E.V. Kuznetsova, T.P. Timchenko, Ya.L. Rusakova, I.S. Murashov, A.A. DokuchaevaStatistical analysis: N.R. Nichay, I.Yu. ZhuravlevaDrafting the article: N.R. Nichay, I.Yu. Zhuravleva, Yu.Yu. Kulyabin, I.S. Zykov, E.V. Boyarkin, O.Yu. Malakhova, T.P. Timchenko, Ya.L. Rusakova, I.S. Murashov, A.A. DokuchaevaCritical revision of the article: N.R. Nichay, I.Yu. Zhuravleva, Yu.Yu. Kulyabin, A.A. Dokuchaeva, A.V. Bogachev-ProkophievFinal approval of the version to be published: N.R. Nichay, I.Yu. Zhuravleva, Yu.Yu. Kulyabin, I.S. Zykov, E.V. Boyarkin, O.Yu. Malakhova, E.V. Kuznetsova, T.P. Timchenko, Ya.L. Rusakova, I.S. Murashov, A.A. Dokuchaeva, A.V. Bogachev-Prokophiev

Introduction: The development of a new generation of hybrid prostheses is a way to improve the results of surgical treatment of combined lesions of the aortic arch and descending aorta. Objective: The study was aimed to evaluate the biocompatibility of the new branched hybrid stent graft.Methods: The developed hybrid stent graft consisted of two parts including the vascular part and the stent graft part, which were supplemented with a stented branch for reconstruction of the left subclavian artery. To assess the biological compatibility, a stent graft was implanted in the descending thoracic aorta in 25 large pigs. The results were assessed by surgical mortality, postoperative complications, selective aortic angiography and histological examination after 6 month follow up period.Results: Implantation of a hybrid stent graft was successful in all cases, without complications. In the early period, 3 animals died. The causes of animal death were respiratory failure caused by lung barotrauma, intraoperative bleeding and sudden cardiac death. The remaining pigs survived until the end of the follow up period without complications and were subsequently withdrawn from the experiment. The duration of perfusion by carotid-femoral bypass surgery was 55 [50; 60] minutes. The volume of blood sweating through the vascular part of the prosthesis was 2.28 ± 0.23 ml/cm2/min; the blood loss for the first hour through drain tube was approximately 70.2 ± 8.9 ml. In 6 months after surgery the aortic angiography showed that the main body and branches of the hybrid stent graft were completely passable. No migration, deformation or endolics were observed. The analysis of histological sections showed the presence of a confluent layer of neointima continuously and evenly distributed throughout the luminal surface of the conduits, including lateral branchlets and anastomoses. The neointima was hyperplasized and represented by layers of unidirectional fibroblast cells, its luminal surface was covered with a layer of endotheliocytes. Conclusion: These results demonstrate the technical feasibility and safety of using a new hybrid stent graft with an additional stented branch. Received 16 July 2024. Revised 1 August 2024. Accepted 15 August 2024. FundingThe study was carried out within the framework of project No. 22-15-20005 (agreement No. 22-15-20005 with the Russian Science Foundation, dated 22.03.2022, agreement No. р-12 with the Ministry of Science and Innovation Policy of the Novosibirsk Region, dated 13.03.2023). Conflict of interestThe authors declare no conflict of interest. Contribution of the authorsConception and study design: A.M. Chernyavskiy, I.Yu. Zhuravleva, D.A. Sirota, A.A. ShadanovData collection and analysis: A.A. Shadanov, D.A. Sirota, M.M. Lyashenko, S.V. Vladimirov, T.P. Timchenko, A.A. Dokuchaeva, V.P. Borodin, A.K. Sabetov, D.V. Khomushku, M.N. Murtazaliev, Ya.L. Rusakova, E.V. KuznetsovaStatistical analysis: A.A. ShadanovDrafting the article: A.A. Shadanov, D.A. SirotaCritical revision of the article: I.Yu. Zhuravleva, D.A. Sirota, A.M. ChernyavskiyFinal approval of the version to be published: A.A. Shadanov, A.M. Chernyavskiy, D.A. Sirota, M.M. Lyashenko, S.V. Vladimirov, T.P. Timchenko, A.A. Dokuchaeva, V.P. Borodin, A.K. Sabetov, D.V. Khomushku, M.N. Murtazaliev, Ya.L. Rusakova, E.V. Kuznetsova, I.Yu. Zhuravleva