Рецепторный механизм инфаркт-лимитирующего эффекта адаптации к нормобарической гипоксии

The aim of the study was to investigate the involvement of bradykinin, cannabinoid and vanilloid (TRPV1 channel) receptors in the implementation of the infarct-limiting effect of chronic normobaric hypoxia (CNH).Materials and methods. The study was performed on male Wistar rats (n = 117) weighing 250–300 g. Adaptation to CNH was modeled for 21 days at 12% pO2, 0.3% pCO2 and normal atmospheric pressure. A day after adaptation of rats to CNH coronary artery occlusion (45 min) and reperfusion (2 h) was performed. In the study the following compounds were used: selective cannabinoid CB1 receptor antagonist rimonabant (1 mg/kg), selective cannabinoid CB2 receptor antagonist AM630 (2.5 mg/kg), selective bradykinin B2 receptor antagonist HOE140 (50 μg/kg), and vanilloid receptor (TRPV1 channel) antagonist capsazepine (3 mg/kg). All antagonists were administered 15 min before coronary artery occlusion.Results. Adaptation to normobaric hypoxia promoted the formation of the pronounced infarct-limiting effect.The blockade of B2 receptor eliminated the infarct-limiting effect of CNH. Blockade of cannabinoid or vanilloidreceptors did not affect the infarct-limiting effect of CNH.Conclusion. The infarct-limiting effect of CNH depends on the activation of B2 receptor, and the adaptive increase in cardiac tolerance to ischemia/reperfusion does not depend on cannabinoid or vanilloid receptors.Цель исследования – изучение участия брадикининовых, каннабиноидных и ваниллоидных рецепторов (TRPV1-каналов) в реализации инфаркт-лимитирующего эффекта хронической нормобарической гипоксии.Материалы и методы. Исследование было выполнено на самцах крыс Вистар (n = 117) массой 250–300 г. Адаптацию к гипоксии (ННГ) моделировали в течение 21 сут при 12% pO2, 0,3% pCO2 и нормальном атмосферном давлении. Через 1 сут после адаптации у крыс воспроизводили коронароокклюзию (45 мин) и реперфузию (2 ч). В исследовании использовали следующие препараты: селективный антагонист каннабиноидных СВ1-рецепторов римонабант (1 мг/кг), селективный антагонист каннабиноидных СВ2-рецепторов AM630 (2,5 мг/кг), селективный антагонист брадикининовых B2-рецепторов HOE140 (50 мкг/кг), антагонист ванилоидных рецепторов (TRPV1-каналов) капсазепин (3 мг/кг). Все антагонисты вводили за 15 мин до коронароокклюзии.Результаты. Адаптация к нормобарической гипоксии приводила к формированию  выраженного инфарктлимитирующего эффекта. Блокада B2-рецепторов устраняла  инфаркт-лимитирующий эффект ННГ. Блокада каннабиноидных или ваниллоидных  рецепторов не влияла на инфаркт-лимитирующее действие ННГ. Заключение. Инфаркт-лимитирующий эффект ННГ зависит от активации B2-рецепторов, а адаптационное повышение толерантности сердца к ишемии и реперфузии не зависит от каннабиноидных или ваниллоидных рецепторов

The infarct-limiting efficacy of deltorphin-II in old rats with diet-induced metabolic syndrome

Background. The discovery of new pharmacological agents for myocardial protection during reperfusion injury is an urgent goal of modern physiology and pharmacology.The aim of the study. To identify the potential for protecting the myocardium from reperfusion injury by administering the delta-2 opioid receptor agonist deltorphin-II prior to reperfusion in old rats with diet-induced metabolic syndrome.Materials and methods. The study was performed on Wistar rats aged 60 days (young rats) and 450 days (old rats) before the onset of a study. Metabolic syndrome (MetS) was modeled for 84 days with a high-carbohydrate high-fat diet (16 % protein, 21 % fat, 46 % carbohydrate) with the replacement of drinking water with 20 % fructose solution. Myocardial infarction was performed by 45-min coronary occlusion followed by 120-min reperfusion; the size of the area of the necrotic myocardium was determined relative to the size of the hypoperfusion zone. The delta-2 opioid receptor agonist deltorphin-II was administered once intravenously 5 minutes before the end of ischemia.Results. It was found that coronary occlusion and subsequent reperfusion both in groups of young and old rats led to the formation of myocardial infarction (necrosis), the size of which was 45 % of the size of the risk zone. Administration of deltorphin-II in old rats led to a limitation of infarct size to 30 % of the size of the risk zone, i. e. 1.7-fold. The use of deltorphin-II in old rats with MetS contributed to a decrease in infarct size to 27 % of the size of the risk zone (1.5 times). The obtained results demonstrate the cardioprotective efficacy of the delta-2 opioid receptor agonist deltorphin-II in aging and metabolic syndrome in rats.Conclusions. These data may serve as a basis for conducting preclinical studies of deltorphin-II as a drug for treatment of acute myocardial infarction

T regulatory lymphocytes and FoxP3 nuclear translocation in various adipose tissue depots in patients with coronary artery disease

T regulatory lymphocytes (Treg) are present is adipose tissue. Their frequency, as well as the level of FoxP3 nuclear translocation, in epicardial and thymus adipose tissue remains unexplored. Properties of adiposeresident Tregs may be of high significance in patients with coronary artery disease as potential pathophysiological factor in the development of atherosclerosis. The aim of the study was to compare frequency of FoxP3+Tregs and FoxP3 nuclear translocation in epicardial, thymus, subcutaneous adipose tissue and peripheral blood in patients with coronary artery disease. A pilot study was conducted in 11 patients with coronary artery disease scheduled for the coronary artery bypass graft surgery after prior selective coronary angiography. Frequency of CD4+CD25hiFoxP3+ and CD4+CD25loFoxP3+ lymphocytes and FoxP3 nuclear translocation were evaluated by imaging flow cytometry in peripheral blood and in stromal vascular fraction of epicardial, subcutaneous and thymus adipose tissue. Frequencies of CD4+CD25hiFoxP3+ and CD4+CD25loFoxP3+ lymphocytes were higher in epicardial adipose tissue compared to blood (3 and 5 times higher, p = 0.020); CD4+CD25loFoxP3+ cells frequency in subcutaneous adipose tissue was 4 times higher than in blood (p = 0.028). The level of FoxP3 nuclear translocation was the highest in blood and decreased in epicardial, subcutaneous and thymus adipose tissue (p = 0.020 both for CD4+CD25hiFoxP3+ and CD4+CD25loFoxP3+ lymphocytes). Frequency of CD4+CD25loFoxP3+ cells was directly related to age in thymus (rs = 0.818; p = 0.002), and inversely in epicardial adipose tissue (rs = -0.618; p = 0.043). Frequencies of CD4+CD25hiFoxP3+ and CD4+CD25loFoxP3+ with FoxP3 nuclear translocation in subcutaneous adipose tissue negatively correlated with age (rs = -0.827; p = 0.002 and rs = -0.648; p = 0.031, respectively). Frequency of CD4+CD25loFoxP3+ cells with FoxP3 nuclear translocation in thymus adipose tissue negatively correlated with waist-to-hip ratio (rs = -0.700; p = 0.016). The severity of atherosclerosis was related only to the frequency of CD4+CD25loFoxP3+ cells in subcutaneous adipose tissue (rs = -0.655; p = 0.029). Thus, epicardial and subcutaneous adipose tissue are enriched with Tregs, but factors that influence Treg accumulation and FoxP3 nuclear translocation in these fat depots may be different. The obtained results may further be used for personalized immunomodulatory therapy in patients with atherosclerosis

Роль вегетативной нервной системы в стресс-индуцированном повреждении сердца

 Aim. To identify the role of the autonomic nervous system in stress cardiomyopathy in an experimental model of Takotsubo syndrome.Materials and methods. The study was carried out on 120 female Wistar rats. Stress modeling was performed by immobilizing animals on the back for 24 hours. Intact rats were used as controls. The rats were decapitated after termination of immobilization under general anesthesia with ether. Stress cardiomyopathy (SCM) was quantified by accumulation of 99mTc pyrophosphate radiopharmaceutical (99mTc PP) in the myocardium. The pharmacological agents used included the ganglionic blocker hexamethonium, administered five times at a dose of 20 mg / kg; guanethidine (50 mg / kg) administered subcutaneously once a day for three days, the last injection was performed 24 hours before immobilization; the muscarinic receptor antagonist atropine methyl nitrate (1 mg / kg); the α1-AR (adrenergic receptor) antagonist prazosin (2 mg / kg); the α2-AR antagonist yohimbine, administered at a dose of 2 mg / kg; the β1-AR antagonist nebivolol (1.2 mg / kg); the β2-AR antagonist ICI 118,551 (0.3 mg / kg); and the β3-AR antagonist L-748337 (0.1 mg / kg).Results. Three-day administration of guanethidine caused a decrease in the degree of 99mTc-PP accumulation in the heart by 35.9%. Hexamethonium did not affect the degree of SCM. The blockade of the muscarinic receptor caused an increase in accumulation of 99mTc-PP by 26.5%. Inhibition of α1-AR did not affect SCM. The blockade of α2-AR caused a 2.2-fold increase in the accumulation compared with stress control. The blockade of β1-AR reduced 99mTc-PP accumulation by 2.5 times. The blockade of β2-AR by ICI 118,551 increased the degree of 99mTcPP accumulation by 34.6%. Inhibition of β3-AR had no effect on SCM.Conclusion. The adrenergic system and β1-adrenergic receptor play an important role in the development of SCM. The parasympathetic nervous system ensures resistance of the heart to stress.Цель. Оценка роли вегетативной нервной системы в стресс-индуцированном повреждении сердца в экспериментальной модели синдрома такотсубо.Материалы и методы. Исследование выполнено на 120 самках крыс линии Вистар. Каждая группа животных состояла из 12 особей. Моделирование стресса осуществляли с помощью иммобилизации животных на спине в течение 24 ч. В качестве контроля использовали интактных особей. Крыс декапитировали после прекращения иммобилизации под общим эфирным наркозом. Количественную оценку стресс-индуцированного повреждения сердца (СИПС) осуществляли по аккумуляции радиофармпрепарата 99mTc-пирофосфата (99mTc-ПФ) в миокарде. Фармакологические агенты вводили внутрибрюшинно: ганглиоблокатор гексаметоний вводили пятикратно в дозе 20 мг/кг; гуанетидин (50 мг/кг) – подкожно 1 раз/сут в течение 3 сут, последнюю инъекцию делали за 24 ч до иммобилизации. Остальные препараты (антагонист М-холинорецепторов атропина метилнитрат (1 мг/кг); антагонист α1-адренорецепторов (АР) празозин (2 мг/кг); антагонист α2-АР йохимбин (2 мг/кг); антагонист β1-АР небиволол (1,2 мг/кг); антагонист β2-АР ICI 118,551 (0,3 мг/кг); антагонист β3-АР L-748337 (0,1 мг/кг)) вводили 2 раза/сут с интервалом 12 ч.Результаты. Трехдневное введение гуанетидина вызвало уменьшение степени аккумуляции 99mTc-ПФ в сердце на 35,9%. Гексаметоний не оказал влияние на степень СИПС. Блокада М-холинорецепторов вызвала усиление аккумуляции 99mTc-ПФ на 26,5%. Ингибирование α1-АР не оказало влияния на СИПС. Блокада α2-АР вызывала усиление аккумуляции в 2,2 раза по сравнению со стресс-контролем. Блокада β1-АР снизила степень аккумуляции 99mTc-ПФ в 2,5 раза. Блокада β2 АР ICI 118,551 увеличила степень аккумуляции 99mTc-ПФ на 34,6%. Ингибирование β3-АР не оказало эффекта на СИПС.Заключение. Симпатоадреналовая система и, в частности, β1-адренорецепторы играют важную роль в развитии СИПС. Парасимпатическая нервная система обеспечивает устойчивость сердца к стрессу

Влияние возраста, высокоуглеводной и высокожировой диеты на развитие артериальной гипертензии и поражения почек в эксперименте

Aim. To identify the structural foundations of the pathogenesis of arterial hypertension and kidney disease associated with a high-fat, high-carbohydrate diet and age.Materials and methods. The study was carried out on male Wistar rats aged 60 and 450 days. The animals were divided into 4 groups: group 1 (n = 14) – intact rats (60 days old) fed with a standard diet for 90 days; group 2 (n = 14) – rats (aged 60 days) receiving a high-fat, high-carbohydrate diet for 90 days; group 3 (n = 14) – intact rats (aged 450 days) receiving a standard diet for 90 days; group 4 (n = 14) – rats (aged 450 days) fed with a high-fat, high-carbohydrate diet for 90 days. Clinical and instrumental research methods, enzyme-linked immunosorbent assay, and immunohistochemistry and histology techniques were used in the study.Results. Feeding 60-day-old animals with a high-fat, high-carbohydrate diet resulted in an increase in body weight and abdominal fat, a rise in systolic blood pressure, and moderately pronounced histologic changes in the kidneys. In intact 450-day-old rats, age-related changes prevailed: changes in the myocardial mass, an increase in TGF-β1, morphological changes in the renal tubules and glomeruli. In 450-day-old rats receiving a high-fat, highcarbohydrate diet, the most pronounced increase in both systolic and diastolic blood pressure, a significant rise in serum fibronectin, and destructive changes in the renal tissue were noted.Conclusion. Functional and biochemical signs of arterial hypertension and morphological changes in the kidneys were the most pronounced in 450-day-old rats fed with a high-fat, high-carbohydrate diet.Цель: выявить структурные основы патогенеза артериальной гипертензии и поражения почек, связанных с высокоуглеводной высокожировой диетой (ВУСЖД) и возрастом у крыс линии Wistar.Материал и методы. Исследование проводили на самцах крыс линии Wistar в возрасте 60 и 450 сут. Животных распределяли на четыре группы: 1-я (n = 14) – интактные крысы (возраст 60 сут), содержащиеся на стандартном рационе в течение 90 сут; 2-я (n = 14) – крысы (возраст 60 сут), содержащиеся на ВУВЖД в течение 90 сут; 3-я (n = 14) – интактные крысы (возраст 450 сут), содержащиеся на стандартном рационе в течение 90 сут; 4-я (n = 14) – крысы (возраст 450 сут), содержащиеся на ВУВЖД в течение 90 сут. Использовались клинико-инструментальный, иммуноферментный, иммуногистохимический и гистологический методы исследования.Результаты. Высокоуглеводная высокожировая диета приводила у 60-дневных животных к увеличению массы тела и абдоминального жира, нарастанию систолического артериального давления, появлению умеренно выраженных гистологических изменений почек. У интактных 450-дневных крыс преобладали изменения, связанные с возрастом: увеличение массы миокарда, увеличение TGF-β1 в сыворотке крови, морфологические изменения почечных канальцев и клубочков. У 450-дневных крыс, содержащихся на ВУВЖД, отмечалось наиболее выраженное нарастание как систолического, так и диастолического артериального давления, значительное увеличение концентрации фибронектина в сыворотке крови, выраженные деструктивные изменения в почечной паренхиме.Заключение. Функциональные и биохимические признаки артериальной гипертензии и морфологические изменения в почках были наиболее выражены у 450-дневных крыс, содержавшихся на ВУВЖД

Is oxidative stress of adipocytes a cause or a consequence of the metabolic syndrome?

Metabolic syndrome is accompanied by oxidative stress in animals and humans. The main source of ROS in experimental metabolic syndrome is NADPH oxidase and possibly adipocyte mitochondria. It is now documented that oxidative stress induces insulin resistance of adipocytes and increases secretion of leptin, MCP-1, IL-6, and TNF-α by adipocytes. It was established that oxidative stress induces a decrease in adiponectin production by adipocytes. It has also been shown that obesity itself can induce oxidative stress. Oxidative stress can cause an alteration of intracellular signaling in adipocytes that apparently leads to the formation of insulin resistance of adipocytes. Chronic stress, glucocorticoids, mineralocorticoids, angiotensin-II, TNF-α also play an important role in the pathogenesis of oxidative stress of adipocytes. Oxidative stress is not only a consequence of metabolic syndrome, but also a reason and a foundational link in the pathogenesis of the metabolic syndrome. Keywords: Metabolic syndrome, Oxidative stress, Adipocyte

The Infarct-Reducing Effect of the δ₂ Opioid Receptor Agonist Deltorphin II: The Molecular Mechanism

The search for novel drugs for the treatment of acute myocardial infarction and reperfusion injury of the heart is an urgent aim of modern pharmacology. Opioid peptides could be such potential drugs in this area. However, the molecular mechanism of the infarct-limiting effect of opioids in reperfusion remains unexplored. The objective of this research was to study the signaling mechanisms of the cardioprotective effect of deltorphin II in reperfusion. Rats were subjected to coronary artery occlusion (45 min) and reperfusion (2 h). The ratio of infarct size/area at risk was determined. This study indicated that the cardioprotective effect of deltorphin II in reperfusion is mediated via the activation of peripheral δ2 opioid receptor (OR), which is most likely localized in cardiomyocytes. We studied the role of guanylyl cyclase, protein kinase Cδ (PKCδ), phosphatidylinositol-3-kinase (PI3-kinase), extracellular signal-regulated kinase-1/2 (ERK1/2-kinase), ATP-sensitive K+-channels (KATP channels), mitochondrial permeability transition pore (MPTP), NO synthase (NOS), protein kinase A (PKA), Janus 2 kinase, AMP-activated protein kinase (AMPK), the large conductance calcium-activated potassium channel (BKCa-channel), reactive oxygen species (ROS) in the cardioprotective effect of deltorphin II. The infarct-reducing effect of deltorphin II appeared to be mediated via the activation of PKCδ, PI3-kinase, ERK1/2-kinase, sarcolemmal KATP channel opening, and MPTP closing