Discovery of the Phenomenon of Intracellular Development of Cardiac Stem Cell: A New Step in Understanding of Biology and Behavior of Tissue-Specific Stem Cells

In our experiments with an in vitro culture of rat cardiac cells, we identified and described for the first time the phenomenon of intracellular development of CSCs in mature CMs with formation of the “cell-in-cell structures” (CICSs). Recently, we have confirmed the reproducibility of our results and existence of this phenomenon in rats of different age groups, 1-year-old bull, adult mice and humans. Moreover, we demonstrated the 5–10 times increase in the amount of CICSs after exposure of in vitro cultures to hypoxia and acidosis, that is, these conditions stimulate intracellular development of CSCs. Our data strongly suggest that transitory amplifying cells (TACs), which release from CICSs, are present as a very rare cell population in adult and old rats. Therefore, we assume that TACs are important for renewal of myocardium during ontogenesis. TACs should be considered as the major source of cells that can reduce myocardial damage in adult mammals with various pathologies of the cardiovascular system. In conclusion, precise and exhaustive analysis of the phenomenon of intracellular development of CSCs, CICSs and TACs will pave the way for cell technologies of new generation in regenerative medicine

Двухмерные и трехмерные модели культур клеток опухолей in vitro: преимущества и недостатки

Discovery and development of new chemical compounds with putative anti-cancer properties requires reliable predictive preclinical models for in vitro screening of efficacy. Such models mainly include cultures of human cancer cells: two-dimensional (2D) and three-dimensional (3D) cell culture systems. In this review, we discuss the molecular aspects of cells cultured in 2D and 3D, and their relevance to cancer study, focusing on key examples from the recent literature. Advantages, disadvantages and perspectives of described models are also analyzed.Синтез и внедрение новых химических соединений, обладающих потенциальной противоопухолевой активностью, требуют надежных предиктивных доклинических моделей для скрининга эффективности in vitro. Такие модели включают культуры клеток опухолей человека – двухмерные системы культур клеток 2D (two-dimensional cell culture systems) и трехмерные системы культур клеток 3D (three-dimensional cell culture systems). В этом обзоре обсуждаются особенности молекулярного фенотипа клеток, культивируемых в 2Dand 3D-системах, и их применение в исследованиях эффективности противоопухолевых препаратов с упором на ключевые примеры из научной литературы. В обзоре также проанализированы преимущества, недостатки и перспективы применения описываемых моделей культур опухолевых клеток

Anatomical Model of Rat Ventricles to Study Cardiac Arrhythmias under Infarction Injury

Species-specific computer models of the heart are a novel powerful tool in studies of life-threatening cardiac arrhythmias. Here, we develop such a model aimed at studying infarction injury in a rat heart, the most common experimental system to investigate the effects of myocardial damage. We updated the Gattoni2016 cellular ionic model by fitting its parameters to experimental data using a population modeling approach. Using four selected cellular models, we studied 2D spiral wave dynamics and found that they include meandering and break-up. Then, using an anatomically realistic ventricular geometry and fiber orientation in the rat heart, we built a model with a postinfarction scar to study the electrophysiological effects of myocardial damage. A post-infarction scar was simulated as an inexcitable obstacle surrounded by a border zone with modified cardiomyocyte properties. For cellular models, we studied the rotation of scroll waves and found that, depending on the model, we can observe different types of dynamics: anchoring, self-termination or stable rotation of the scroll wave. The observed arrhythmia characteristics coincide with those measured in the experiment. The developed model can be used to study arrhythmia in rat hearts with myocardial damage from ischemia reperfusion and to examine the possible arrhythmogenic effects of various experimental interventions. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This study has been supported by a grant from the Ministry of Science and Higher Education of the Russian Federation (agreement № 075-15-2020-800)

Anatomical model of rat ventricles to study cardiac arrhythmias under infarction injury

Species-specific computer models of the heart are a novel powerful tool in studies of life-threatening cardiac arrhythmias. Here, we develop such a model aimed at studying infarction injury in a rat heart, the most common experimental system to investigate the effects of myocardial damage. We updated the Gattoni2016 cellular ionic model by fitting its parameters to experimental data using a population modeling approach. Using four selected cellular models, we studied 2D spiral wave dynamics and found that they include meandering and break-up. Then, using an anatomically realistic ventricular geometry and fiber orientation in the rat heart, we built a model with a post-infarction scar to study the electrophysiological effects of myocardial damage. A post-infarction scar was simulated as an inexcitable obstacle surrounded by a border zone with modified cardiomyocyte properties. For cellular models, we studied the rotation of scroll waves and found that, depending on the model, we can observe different types of dynamics: anchoring, self-termination or stable rotation of the scroll wave. The observed arrhythmia characteristics coincide with those measured in the experiment. The developed model can be used to study arrhythmia in rat hearts with myocardial damage from ischemia reperfusion and to examine the possible arrhythmogenic effects of various experimental interventions.Cardiolog

Effect of the qualitative composition of a high-fat diet in rats with systemic inflammatory response syndrome upon myocardial resistance to ischemic-reperfusion injury and cytokine levels

Overweight and obesity are among the main factors of cardiovascular risk, but the prospective studies on the dependence between high-fat diets and weight gain yielded contradictory results. Different types of fats exert varying metabolic effects, and this fact leads to a difference in the risk associated with increasing body weight. The effects of fat quality in the daily diet on immunological status and resistance of myocardium to ischemic-reperfusion damage should be studied experimentally in biomedical models. The purpose of this work was to assess the effect of the qualitative composition of a high-fat diet used for induction of primary visceral obesity (PVO) in rats with systemic inflammatory response syndrome (SIRS) upon myocardial resistance to ischemic-reperfusion injury, and levels of pro- and anti-inflammatory cytokines.The experiments were performed on adult male Wistar rats with PVO caused by 28-day consumption of any fat types: hydrogenated fats (HF), vegetable oils (VO), animal fats (AF) or milk fat (MF). The SIRS model included a combination of chemically induced colitis (CIC) and intragastric injection of a broad-spectrum antimicrobial agent (AMA) for three days. Five days later, immunological and biochemical studies were conducted, as well as composition of intestinal microbiota in faecal samples, morphological changes in the structure of the large intestine, hemodynamic parameters and myocardial resistance to ischemic-reperfusion injury were studied in the model of isolated heart perfusion, by Langendorff technique.There was a significant increase in the concentration of anti-inflammatory cytokines in animals with SIRS, i.e., TNFα, IL-1α, IL-2, IL-8, as well as a decrease in TGF-1β, an anti-inflammatory cytokine. SIRS was accompanied by severe dietary disorders and evacuatory function of the gastrointestinal tract. Minimal changes in the intestinal microbiota composition, as well as the most pronounced regeneration signs of intestinal epithelium was observed in rats in the group with MF injection. There was a trend for increasing size of infarction in all the groups as compared with control, directly correlating with increase in BDNF and IL-2 production. However, a significant increase in the infarction size was found only in the group receiving milkfat, thus suggesting a decrease in myocardial resistance to ischemic reperfusion injury (IRI).Thus, the presence of SIRS in the primary obesity model is characterized by controllable change of inflammation markers and depends on the quality of dietary fats. The degree of morphofunctional deterioration of isolated heart, including a decrease in resistance to ischemia-reperfusion injury, correlates with the concentration of BDNF and IL-2 during the studied observation terms

Прямое сравнение кардиопротективных свойств ингибиторов некроптоза на модели глобальной ишемии-реперфузии изолированного сердца крысы

The study was aimed at comparative assessment of cardioprotective properties of various necroptosis inhibitors in the isolated perfused rat heart subjected to global ischemia-reperfusion.Materials and Methods. The study was performed on 38 male Wistar rats weighting 250–300 g. The following necroptosis inhibitors were tested: necrostatin-1 (Nec-1), necrostatin-5 (Nec-5), necrostatin-1s (Nec1s), and necrosulfonamide (NSA). All tested substances were administered intraperitoneally (i.p.) 1 hour prior to heart perfusion. Control animals were treated either with the vehicle (dimethyl sulfoxide, DMSO) or with 0,9% sodium chloride solution (Controls). The dose of necroptosis inhibitors was calculated on the basis of effective concentration (EC50) data. One hour after i.p. injection, the animals were anesthetized, the hearts were rapidly excised, the aorta was cannulated and retrogradely perfused according to Langendorff. After stabilization, the perfusion was stopped for 35 minutes, which was followed by 2 hours of reperfusion. Prior to stabilization, fluid-filled polyethylene balloon was placed into the left ventricle for left ventricular pressure registration. Coronary flow was measured at baseline and during reperfusion by means of perfusate collection. The volume of necrotic myocardium was expressed as a percentage of triphenyltetrazolium chloride-negative tissue relative to the entire heart volume.Results. The volume of myocardial necrosis and functional heart parameters were not different between Controls and DMSO group. All tested necroptosis inhibitors demonstrated infarct-limiting effect. However, there were no differences between the groups. The volume of necrotic myocardium was (50,5 ± 7,82)%, (29,9 ± 3,42)%, (27,7 ± 3,42)%, (30,6 ± 3,82)%, and (34,7 ± 5,82)% in DMSO, Nec-1, Nec-5, Nec-1s, and NSA groups, respectively (p < 0,01 vs. DMSO group).Nec-1s and NSA were shown to improve functional recovery of the heart after ischemia. In particular, left ventricular developed pressure and coronary flow rate were higher in Nec-1s and NSA groups (p < 0,01 compared with Controls and DMSO), while end-diastolic pressure was lower in Nec-1s and NSA groups vs. Controls and DMSO (p < 0,01).Conclusions. It has been shown that Nec-1, Nec-5, Nec-1s, and NSA administration prior to global ischemiareperfusion results in comparable infarct size limitation. In addition to infarct size limitation, Nec-1s and NSA are able to improve postischemic left ventricular function. This fact, along with low toxicity and optimal EC50, makes Nec-1s and NSA perspective candidates for preclinical and clinical development as cardioprotective agents. Цель исследования – провести сравнительную оценку кардиопротективных эффектов различных ингибиторов некроптоза на модели глобальной ишемии-реперфузии изолированного перфузируемого сердца крысы.Материал и методы. Исследование выполнено на 38 крысах стока Wistar массой 250–300 г. Исследовались кардиопротективные эффекты следующих ингибиторов некроптоза: некростатина-1 (Nec-1), некростатина-5 (Nec-5), некростатина-1s (Nec-1s), некросульфонамида (NSA). Все исследуемые соединения вводились внутрибрюшинно за 1 ч до начала эксперимента. В отдельных группах животным вводили растворитель для ингибиторов некроптоза диметилсульфоксид (ДМСО) и 0,9%-й раствор хлорида натрия (контроль). Через 1 ч после внутрибрюшинной инъекции у крыс извлекалось сердце, производилось канюлирование аорты и подключение сердца к модифицированному аппарату Лангендорфа. Путем прекращения ретроградной перфузии сердца оксигенированным раствором Кребса моделировалась нормотермическая 35-минутная глобальная ишемия, по окончании которой восстанавливалась ретроградная перфузия в течение 2 ч. До моделирования ишемии в полость левого желудочка вводился заполненный жидкостью баллон для регистрации внутрижелудочкового давления. Скорость коронарного потока определялась исходно и в период реперфузии по объему оттекающего от сердца перфузата. Объем некроза миокарда выражали в процентах от общего объема сердца после гистохимической окраски срезов сердец трифенилтетразолием хлоридом.Результаты. Группы контроля и ДМСО не различались по объему некроза миокарда и функциональным параметрам работы сердца. По результатам проведенных экспериментов можно утверждать, что все ингибиторы некроптоза обладают инфаркт-лимитирующим эффектом, при этом статистически значимых различий показателей у животных, которым вводились различные ингибиторы некроптоза, не выявлено. Объем некроза миокарда в группе ДМСО составил (50,5 ± 7,82)%, в то время как в группе Nec-1 – (29,9 ± 3,42)%, в группе Nec-5 – (27,7 ± 3,42)%, в группе Nec-1s – (30,6 ± 3,82)%, в группе NSA – (34,7 ± 5,82)% (p < 0,01 в сравнении с ДМСО для каждой из групп ингибиторов некроптоза). Выявлена способность двух ингибиторов некроптоза, а именно Nec-1s и NSA, улучшать функциональное состояние миокарда, что проявлялось в более высоком уровне пульсового давления (p < 0,01 по сравнению с контролем и ДМСО), скорости коронарного потока (p < 0,05 по сравнению с контролем и ДМСО), а также в более низком уровне диастолического внутрижелудочкового давления (p < 0,01 по сравнению с контролем и ДМСО) в ходе реперфузии.Заключение. Результаты проведенного исследования демонстрируют наличие у всех изученных ингибиторов некроптоза инфаркт-лимитирующего эффекта одинаковой степени выраженности. Однако Nec-1s и NSA выделяет способность улучшать функциональное состояние миокарда в периоде реперфузии, что с учетом их низкой токсичности и более низкой EC50 позволяет рассматривать их в качестве перспективных соединений кардиопротективного действия для последующих доклинических и клинических исследований.

Modeling of systemic inflammatory response syndrome by chemical induction of colon injury in rats

Our objective was to develop a model of systemic inflammatory response syndrome (SIRS) by chemical induction of colon injury and antibiotic-associated intestinal dysbiosis in rats with primary visceral obesity (PVO) for studies of myocardial resistance to ischemia-reperfusion injury. The experiments were performed with adult Wistar male rats with PVO under improved conditions of a conventional animal clinic. The chemically induced inflammatory colon disease (CIICD) was accomplished by intragastric administration of a mixture of broad-spectrum antimicrobial agents (AMA) for 3 days. Five days later, immunological and biochemical studies were carried out, as follows: composition of the intestinal microbiota in feces and shortchain fatty acids in blood, morphological changes in the structure of the colon, hemodynamic parameters and myocardial stability with modified Langendorff system. In PVO rats, the mass of visceral fat deposits and the content of lipopolysaccharides (LPS) in the blood were significantly increased when giving them fatcarbohydrate diet (FCD). In animals with CIICD, in addition to LPS, there was a significant increase in proinflammatory cytokine concentration (TNF, IL-8, MCP-1), and after oral administration of the AMA mixture, pronounced disturbances of food behavior and evacuatory function of gastrointestinal tract, deep destructive changes in colon, as well as qualitative and quantitative composition of intestinal microbiota with characteristics typical to the first-grade dysbiosis. High levels were shown for IL-8 cytokine only. An increase in acetic and propionic acid concentrations were shown in blood in animals with CIICD, and, to a greater extent, in rats with antibiotic-induced dysbiosis (AID). FCD was followed by significantly reduced levels of lactobacilli and bifidobacteria in colonic contents. CIICD leads to detection of Escherichia coli, and intestinal dysbiosis leads to the manifestation of Proteus. A comorbid combination of pathological changes in the immune and digestive systems caused a significant increase in the area of myocardial necrosis (by 35 percent) in isolated heart by, thus presuming decreased myocardial resistance to ischemia-reperfusion injury (IRI). The SIRS model induced by chemical trauma to large intestine is aggravated by the introduction of AMAs mixture, and it is characterized by a controlled change in inflammatory markers. Deterioration of morphofunctional characteristics in isolated heart included decrease in resistance to IRI seems to correspond to acute inflammatory bowel disease with induced intestinal dysbiosis. This model can be used in experimental medicine in the field of cardiology, endomicroecology, gastroenterology, and immunology

Comparative evaluation of empagliflozin, canagliflozin and sitagliptin cardioprotective properties in rats with experimental type 2 diabetes mellitus

Background: Myocardial infarction (MI) is one of the leading causes of mortality in patients with type 2 diabetes mellitus (DM), therefore it is essential to give preference to a glucose-lowering drug having optimal cardioprotective properties. A comparative study of the various sodium-glucose co-transporter inhibitors representatives’ protective effects in experimental MI was not carried out within the framework of one study.Aim: To evaluate the influence of empagliflozin (EMPA) and canagliflozin (CANA), in comparison with sitagliptin (SITA), on hemodynamic parameters and myocardial damage area in rats with diabetes type 2 model in experimental MI.Materials and methods: Type 2 DM was modelled in Wistar rats by means of 4-week high-fat diet followed by nicotinamide 230 mg/kg and streptozotocin 60 mg/kg administration. 4 weeks after DM induction the following groups were made: «DM+SITA» — treatment with SITA 50 mg/kg, «DM+EMPA» — treatment with EMPA 2 mg/kg, «DM+CANA» — treatment with CANA 25 mg/kg per os once daily for 8 weeks. Animals in «DM» group remained untreated for the following 8 weeks. Rats in control group were fed with standard chow. 16 weeks after the experiment beginning transient global myocardial ischemia was modelled in all rats. Hemodynamic parameters and myocardium necrosis area were evaluated.Results: The necrosis area was larger in «DM» group, than in control one (p=0.018). Infarction size in «DM+SITA» did not differ from that in «DM» group (62.92(41.29;75.84) and 57.26(45.51;70.08)%, р=0.554). Necrosis area in «DM+EMPA» and «DM+CANA» groups was smaller than in «DM» group (37.90(20.76;54.66)%, 46.15(29.77;50.55) vs 57.26(45.51;70.08)%, р=0.008 and р=0.009, respectively). Necrosis size did not differ between «DM+EMPA» and «DM+CANA» groups (p=0.630). Ischemic contracture in «DM+CANA» group was less prominent than under the use of all other glucose-lowering drugs. We observed increase of coronary blood flow in «DM+EMPA» group, in comparison with «DM», «DM+CANA» and «DM+SITA» groups.Conclusions: SITA does not have cardioprotective effect in ischemia-reperfusion injury in diabetic rats. EMPA and CANA have similarly prominent infarct-limiting properties. EMPA is able to increase coronary blood flow, whereas cardioprotective action of CANA is associated with ischemic contracture diminishing

Influence on the autonomic cardiovascular system regulation in the treatment of hypertension, arrhythmias and heart failure

Cardiovascular diseases are widespread and are the leading death cause in most countries, despite the creation and improvement of strategies to reduce cardiovascular risk. A significant role in the development and evolution of cardiovascular diseases belongs to sympathetic nervous system hyperactivity, and therefore the methods of effecting it are relevant for the prevention and treatment of cardiovascular pathology. The article discusses modern approaches to interventional and conservative regulation of the autonomic nervous system and neuromodulation in the prevention and treatment of hypertension, heart failure, tachyarrhythmias, as well as reflects a conjoint expert judgment on these issues