Tissue Respiration Research Articles

Identification of hypoxene metabolites in urine samples using gas chromatography–tandem mass spectrometry for anti-doping control

Objectives. Hypoxen is a drug which possesses antioxidant and antihypoxic effects. It achieves this by increasing the utilization of oxygen by mitochondria, intensifying oxidative phosphorylation, and as a result, improving tissue respiration. Athletes take it during prolonged exercise, in order to increase efficiency and reduce physical overwork. Since 2023, the World Anti-Doping Agency has included the drug in the monitoring program, in the belief that it can be used to gain a competitive advantage. It is thus a candidate for inclusion in the Prohibited List as a potential regulator of the human metabolism. Currently, there are no studies or scientific publications focusing on the identification of hypoxene in biofluids for the purpose of anti-doping control. The aim of this study is to determine the possible metabolites of the drug and their chromato-mass spectrometric characteristics in urine samples using gas chromatography–tandem mass spectrometry (GC–MS/MS) for doping control screening purposes.Methods. Sample preparation of urine samples was carried out using enzymatic hydrolysis, liquid–liquid extraction and derivatization. The GC–MS/MS method was used for analysis. Screening of hypoxene metabolites was carried out in the mode of total ion current after fragmentation of selected parent ions.Results. Three specific metabolites of hypoxene (m/z 342, 300, and 346, including trimethylsilyl derivatives) were identified in urine samples of volunteers (n = 3). They can act as markers for taking the target antihypoxant, and their possible structural formulas are given. The excretion curves of two metabolites with an m/z of 300 and 346 respectively in urine were studied. The maximum concentration is reached after 8–14 and 1.5–6 h, respectively. It was established, that these metabolites are reliably identified in urine 90 h or more after a single dose of the drug.Conclusions. Possible structures of hypoxene metabolites in urine samples from volunteers were determined for the first time and their chromato-mass spectrometric characteristics were established. The approach developed in this study can be used for screening analysis of hypoxene for the purpose of anti-doping control.

Female Specific Restrictive Cardiomyopathy and Metabolic Dysregulation in transgenic mice expressing a Peptide of the Amino-Terminus of GRK2.

Cardiovascular disease and heart failure are a major health challenge, with sex differences in pathophysiology and treatment responses critically influencing patient outcomes. G protein-coupled receptor (GPCR) kinase 2 (GRK2) is a pivotal regulator of cellular signaling whose elevation is a hallmark of heart failure progression. Its complex network of protein interactions impact a wide range of physiological and pathophysiological processes including cardiac function. In this study, we examined the effects of cardiac-restricted expression of an amino-terminal peptide of GRK2 (βARKnt) in female mice subjected to acute and chronic pressure overload. Our findings reveal that that βARKnt affects hypertrophy development and cardiac function differently in female mice than in males, leading to a transition to heart failure not observed in control females or βARKnt males. Notably, the βARKnt female mice exhibited baseline hypertrophy with distinct left atrial morphology, increased fibrosis, and immune cell infiltration compared to the controls, which progressed under chronic stress, indicating adverse cardiac remodeling. Furthermore, βARKnt female mice, unlike males, exhibit impaired tissue respiration following acute pressure overload and altered glucose sensitivity and insulin tolerance, highlighting significant remodeling of cardiac and systemic metabolism.

FUNCTIONAL STATE OF RENAL PARENCHYMA IN CHILDREN WITH DYSMETABOLIC NEPHROPATHY

Abstract. Metabolic nephropathy in children is a relevant issue in our time, as the prevalence of this disease is increasing. Negative consequences of metabolic nephropathy include a gradual deterioration of kidney function. A significant aspect is the fact that metabolic nephropathy can lead to the development of chronic kidney disease in children. Chronicity requires continuous medical monitoring and treatment to support kidney function and prevent further complications, such as renal insufficiency and other metabolic disorders. There is no doubt that one of the leading pathogenetic factors in kidney dysfunction is hypoxia. It can be caused by both hemodynamic disturbances associated with renal pathology and tissue respiration disorders in congenital dysplasia of the kidney's connective tissue, which arises in the embryo under the influence of epigenetic factors in utero and is further exacerbated by various epigenetic factors in postnatal life. Purpose of the work to investigate the functional state of kidney parenchyma in children with dysmetabolic nephropathy. Materials and methods. Two groups of children were examined: those with a complicated course of dysmetabolic nephropathy, a history of inflammatory episodes of the urinary system organs (Group I - UN, 52 children), and dysmetabolic nephropathy with persistent crystalluria (Group II - DN, 56 children). A control group consisted of 65 healthy children. Tubular reabsorption, as a partial function of the proximal segment of the nephrons, was assessed based on urinolysis test data, specifically the levels of excretion of inorganic phosphates, proteinuria, amino acids, reduced sugars (maltose, sucrose, fructose by Benedict's test), glucose (by Gaines's test), and calcium (by Sulcovitch's test). The level of creatinine and glycosaminoglycan (GAG) excretion in daily urine in children with dysmetabolic nephropathy was determined and compared with data from healthy children in the control group. Research results. In children from both observation groups, a significantly high frequency of hyperphosphaturia (94.23% and 96.42%), calciuria (94.23% and 89.28%), glucosuria (78.85% and 73.21%), increased excretion of amino acids in the urine (40.38% and 37.5%), microproteinuria (32.69% and 28.57%), and increased excretion of reduced sugars (28.85% and 26.79%) were observed. The daily excretion of creatinine, glycosaminoglycans, and oxypyrrolidine in the urine of children with dysmetabolic nephropathy indicates a significantly reduced level of creatinine in the daily urine in the majority of children in Group I (0.56±0.19 g/L, 80.77% of those examined) and more than half of the children in Group II (0.83±0.08 g/L, 57.14% of those examined), compared to the data from healthy children in the control group (1.25±0.75 g/L, 0.0%). Conclusions. The analysis of the functional state of the kidney tissue in oxalate dysmetabolic nephropathy in children allows us to testify to the presence of tubular and glomerular partial renal tissue failure. Significant decreases in creatinine excretion and increased excretion of glycosoaminoglycans in the urine and significantly higher levels of oxyproline in the urine indicate the presence of glomerular type partial renal failure in oxalate dysmetabolic nephropathy in children and the presence of undifferentiated dysplasia of the renal connective tissue with the onset of its sclerosis with subsequent transition to interstitial nephritis. The presence of these changes in the vast majority of children with complicated course of oxalate dysmetabolic nephropathy in the period of clinical and laboratory remission of the inflammatory process indicates the priority of renal connective tissue dysplasia and paucity of renal failure in the pathogenesis of dysmetabolic nephropathy and its severity in children. Indicators of oxyproline creatinine, glycosoaminoglycans and oxyproline excretion can be used as epigenetic markers of susceptibility to dysmetabolic nephropathy in general and its more severe course in particular. Keywords: dysmetabolic nephropathy, functional state, kidney parenchyma, nephron.

CORRECTION OF HEALTH DEVIATIONS CAUSED BY UNFAVORABLE ENVIRONMENTAL CONDITIONS USING NON-PHARMACOLOGICAL MEANS

Lack of atmospheric oxygen (exogenous hypoxia) in residents of high mountain areas leads to functional disturbances of blood circulation, blood composition, activity of tissue respiration enzymes and resulting other biochemical abnormalities, causing a number of diseases. And the open mines operating in these regions create an unfavorable ecological environment, contributing to the deepening of functional disorders of the body among the population. Adolescents in this region are also at risk for the development of pathological processes. These risks can be reduced, and diseases can be prevented using non-drug means, using herbs with antihypoxic effects and special breathing exercises.

Nr4a3 Loss Impairs Adipose Mitochondrial Respiration Through Downregulaion of Mek1

Type 2 diabetes mellitus (T2D) is a chronic condition affecting nearly half a billion people worldwide. Symptoms of T2D include impaired glucose tolerance, decreased insulin secretion and significant weight gain. While the symptoms of T2D are well-documented, the underlying pathology remains unclear. Recent research has indicated the critical role of the nuclear receptor Nr4a3 in the development of glucose intolerance and weight gain. In individuals with T2D, the Nr4a3 promoter is hypermethylated, leading to decreased Nr4a3 expression. Elucidating the role of Nr4a3 in mitochondrial respiration in adipose will help define the mechanism of T2D onset and treatment. Here we demonstrate the effect of systemic Nr4a3 loss. Full body Nr4a3 KO animals were fed a standard diet. Male, but not female, Nr4a3 KO mice demonstrate impaired glucose and insulin tolerance. Male Nr4a3 KO mice have normal muscle, liver, and kidney respiration rates, while adipose tissue respiration is impaired. The impaired adipose respiration corresponds with increased mass of all adipose depots, increased adipocyte size, and increased lipid droplet size. The analysis of electron transport chain and tricarboxylic acid complex proteins did not reveal significant differences. Instead, the altered respiration is attributed to a decreased Mek1 protein level, and decreased phosphorylation and activation of its downstream target DRP1. Our data demonstrate the critical role of Nr4a3 in adipose tissue through regulating mitochondrial function. NIH R15DK124835-01A1. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

NDUFA9 and its crotonylation modification promote browning of white adipocytes by activating mitochondrial function in mice

Protein crotonylation plays a role in regulating cellular metabolism, gene expression, and other biological processes. NDUFA9 (NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9) is closely associated with the activity and function of mitochondrial respiratory chain complex I. Mitochondrial function and respiratory chain are closely related to browning of white adipocytes, it’s speculated that NDUFA9 and its crotonylation are associated with browning of white adipocytes. Firstly, the effect of NDUFA9 on white adipose tissue was verified in white fat browning model mice, and it was found that NDUFA9 promoted mitochondrial respiration, thermogenesis, and browning of white adipose tissue. Secondly, in cellular studies, it was discovered that NDUFA9 facilitated browning of white adipocytes by enhancing mitochondrial function, mitochondrial complex I activity, ATP synthesis, and mitochondrial respiration. Again, the level of NDUFA9 crotonylation was increased by treating cells with vorinostat (SAHA)+sodium crotonate (NaCr) and overexpressing NDUFA9, it was found that NDUFA9 crotonylation promoted browning of white adipocytes. Meanwhile, the acetylation level of NDUFA9 was increased by treating cells with SAHA+sodium acetate (NaAc) and overexpressing NDUFA9, the assay revealed that NDUFA9 acetylation inhibited white adipocytes browning. Finally, combined with the competitive relationship between acetylation and crotonylation, it was also demonstrated that NDUFA9 crotonylation promoted browning of white adipocytes. Above results indicate that NDUFA9 and its crotonylation modification promote mitochondrial function, which in turn promotes browning of white adipocytes. This study establishes a theoretical foundation for the management and intervention of obesity, which is crucial in addressing obesity and related medical conditions in the future.

Correlation between molecules, which reflect malfunctioning of cellular respiration, degree of oxidative stress, and glycated hemoglobin in retinopaties with type 2 diabetes

Introduction. The pathogenetic role of biochemical changes in the development of diabetic retinopathy (DR) is undoubted and determines the importance of studies that reveal metabolic disorders of both individual molecules and show the relationships between them. Because of some commonalities between tissue respiration, monosaccharide and tryptophan exchange, and activation of lipid peroxidation (LP), there is an interest in studying the relationship between metabolites of these pathways in retinopathy.Aim. The aim is to study the content of metabolites of the kynurenic pathway and intermediate product of lipid peroxidation in blood, and to reveal the correlation between them and glycated hemoglobin’s (HbA1c) level in retinopathy with type 2 diabetes.Materials and methods. The 1st group (control group) included 21 healthy people; the 2nd group included 21 people with «prediabetes», the 3rd group - 21 patients with type 2 diabetes, the 4th group - 63 people with type 2 diabetes and diabetic retinopathy (DR) of varying severity levels. The content of kynurenines in the blood plasma (kynurenine (KYN), 3-hydroxykynurenine (3-HKYN), kynurenic acid (KYNA)) of all participants, as well as the concentration of malondialdehyde (MDA) was determined by high-performance liquid chromatography using a Shimadzu LC-20 chromatograph (Japan). The level of glycated hemoglobin (HbA1c) was determined using Beckman Coulter AU 480 (USA) biochemical analyzer. The results were calculated using Jamovi program version 2.3.Results. In the group of people with «prediabetes», the values of all studied parameters in the blood plasma were increased in comparison with the control group. In the group of patients with type 2 diabetes, the levels of KYN, 3- НKYN and MDA significantly exceeded those in the group of people with «prediabetes». In the group of people with DR, all indicators remained high, the values of 3-НKYN and KYNA showed a statistical difference compared to the group of patients with diabetes. When conducting a correlation analysis, corellations were identified between the level of HbA1c on the one hand and the values of KYN (r=0.77; p ˂ 0.001), concentrations of 3-НKYN (r=0.80; p ˂ 0.001), KYNA (r= 0.72; p ˂ 0.001) and MDA (r=0.84; p ˂ 0.001) – on the other. There was a correlation between HbA1c level and fundus scale (r=0.82; p ˂ 0.001) and between concentrations (of 3-HKYN) and MDA (r=0.50; p=0.002).Conclusion. An increased level of glycosylated hemoglobin and lipid peroxidation products in the blood during retinopathy against the background of type 2 diabetes, an increase in the concentrations of KYN, 3-HKYN, KYNA, and the presence of correlations between these indicators serve as the basis for proving the relationship of uncontrolled hyperglycemia with changes in cellular respiration and the development of oxidative stress. Hypoxic effects and the accumulation of intermediate metabolic products of the kynurenine pathway contribute to progressive neurovascular damage to the retina, activation of lipid peroxidation processes and inflammation.

IDF23-0273 Nutrient overload and insulin resistance can precede reductions in mitochondrial respiration in omental adipose tissue

IDF23-0273 Nutrient overload and insulin resistance can precede reductions in mitochondrial respiration in omental adipose tissue

Correlation of mitochondrial respiration in platelets, peripheral blood mononuclear cells and muscle fibers

There is a growing interest for the possibility of using peripheral blood cells (including platelets) as markers for mitochondrial function in less accessible tissues. Only a few studies have examined the correlation between respiration in blood and muscle tissue, with small sample sizes and conflicting results.This study investigated the correlation of mitochondrial respiration within and across tissues. Additional analyses were performed to elucidate which blood cell type would be most useful for assessing systemic mitochondrial function.There was a significant but weak within tissue correlation between platelets and peripheral blood mononuclear cells (PBMCs). Neither PBMCs nor platelet respiration correlated significantly with muscle respiration.Muscle fibers from a group of athletes had higher mass-specific respiration, due to higher mitochondrial content than non-athlete controls, but this finding was not replicated in either of the blood cell types. In a group of patients with primary mitochondrial diseases, there were significant differences in blood cell respiration compared to healthy controls, particularly in platelets. Platelet respiration generally correlated better with the citrate synthase activity of each sample, in comparison to PBMCs.In conclusion, this study does not support the theory that blood cells can be used as accurate biomarkers to detect minor alterations in muscle respiration. However, in some instances, pronounced mitochondrial abnormalities might be reflected across tissues and detectable in blood cells, with more promising findings for platelets than PBMCs.

Biological availability of mineral elements

The animal husbandry industry is the leading branch of our country’s agro-industrial complex, on the one hand, its development determines the level of public consumption of valuable food products, and on the other hand, the economic well-being of the agricultural sector of the economy. It is known that the productivity of farm animals depends on feeding and keeping conditions by 70–80 % and on genetic potential by 20–30 %. Balanced animal nutrition is an important part of the efforts to increase livestock productivity, it is based on meeting the energy and nutrient needs of animals and poultry at different ages. If this requirement is met, you can expect high growth and development of young animals, and high productivity. The application of biologically active substances, including minerals, as catalysts for metabolism is one of the means to increase animal productivity and resistance. Numerous studies have proven their significant role in the processes of tissue respiration, hematopoiesis, reproduction, nervous and endocrine system functions, and consequently in the processes of strengthening the natural immune defenses of animals. Breeders use different sources of macro- and microelements to compensate mineral deficiencies in the diet. It can be mineral additives of industrial production, or natural sources or industrial waste containing certain mineral elements. The availability of certain macro- and microelements in mineral sources, the cost of these additives, and the costs of their purchase and transportation are important. Particular attention is paid to the mineral nutrition of poultry, which has high growth energy, intensive metabolism and a well-developed reproductive function. Special attention is focused on the mineral nutrition of poultry, as they have high growth energy, intensive metabolism and a well-developed reproductive function. An unbalanced mineral nutrition significantly reduces the body’s productivity and resistance, causes significant metabolic disorders, reproductive disorders and diseases, which can often cause poultry death. The most common reason for the declining productivity and immune system is insufficiently balanced feeding in the conditions of production intensification. The intensive use of poultry causes changes in metabolism, reducing the content of micro and macro elements, vitamins and other biologically active substances in the body.

ISG15 blocks cardiac glycolysis and ensures sufficient mitochondrial energy production during Coxsackievirus B3 infection.

Virus infection triggers inflammation and, may impose nutrient shortage to the heart. Supported by type I interferon (IFN) signalling, cardiomyocytes counteract infection by various effector processes, with the IFN-stimulated gene of 15 kDa (ISG15) system being intensively regulated and protein modification with ISG15 protecting mice Coxsackievirus B3 (CVB3) infection. The underlying molecular aspects how the ISG15 system affects the functional properties of respective protein substrates in the heart are unknown. Based on the protective properties due to protein ISGylation, we set out a study investigating CVB3-infected mice in depth and found cardiac atrophy with lower cardiac output in ISG15-/- mice. By mass spectrometry, we identified the protein targets of the ISG15 conjugation machinery in heart tissue and explored how ISGylation affects their function. The cardiac ISGylome showed a strong enrichment of ISGylation substrates within glycolytic metabolic processes. Two control enzymes of the glycolytic pathway, hexokinase 2 (HK2) and phosphofructokinase muscle form (PFK1), were identified as bona fide ISGylation targets during infection. In an integrative approach complemented with enzymatic functional testing and structural modelling, we demonstrate that protein ISGylation obstructs the activity of HK2 and PFK1. Seahorse-based investigation of glycolysis in cardiomyocytes revealed that, by conjugating proteins, the ISG15 system prevents the infection-/IFN-induced up-regulation of glycolysis. We complemented our analysis with proteomics-based advanced computational modelling of cardiac energy metabolism. Our calculations revealed an ISG15-dependent preservation of the metabolic capacity in cardiac tissue during CVB3 infection. Functional profiling of mitochondrial respiration in cardiomyocytes and mouse heart tissue by Seahorse technology showed an enhanced oxidative activity in cells with a competent ISG15 system. Our study demonstrates that ISG15 controls critical nodes in cardiac metabolism. ISG15 reduces the glucose demand, supports higher ATP production capacity in the heart, despite nutrient shortage in infection, and counteracts cardiac atrophy and dysfunction.

Effects of Genotype and Modified Atmosphere Packaging on the Quality of Fresh-Cut Melons.

Marketing melons (Cucumis melo) as convenient fresh-cut products is popular nowadays. However, damage inflicted by fresh-cut processing results in fast quality degradation and food safety risks. The life of fresh-cut produce can be extended by a modified atmosphere (MA), either generated in a package by tissue respiration (a passive MA) or injected by gas flushing (an active MA). This work investigated the effect of passive and active MA formed in packages of different perforation levels on the quality of fresh-cut melons of two genetic groups: C. melo var. cantalupensis, characterized by climacteric fruit behavior, and non-climacteric C. melo inodorus. The best product preservation was achieved in passive MA packages: non-perforated for inodorus melons and micro-perforated for cantalupensis ones. The optimal packages allowed for the preservation of both genotypes for 14 days at 6-8 °C. The major factors limiting the shelf life of fresh-cut melons were microbial spoilage, translucency disorder and hypoxic fermentation associated with cantalupensis melons with enhanced ethyl acetate accumulation. Inodorus melons were found to be preferable for fresh-cut processing since they were less prone to fermented off-flavor development.

Pathogenetic basis of optic nerve atrophy in methanol poisoning

Optic nerve atrophy is a pathomorphological consequence of diseases of the peripheral neuron of the visual pathway, manifested as atrophy of nerve fibers of varying severity. The toxic effect of methanol is mainly associated with formic acid and formaldehyde, which suppress the cytochrome system, inhibit oxidative phosphorylation, and thereby cause a deficiency of adenosine triphosphoric acid, to which brain and retinal tissues are especially susceptible. When formiate accumulates, tissue respiration is disrupted, leading to pronounced tissue hypoxia. As a result of such methanol metabolism, metabolic acidosis occurs. Tissue hypoxia develops in the first few hours as a result of the action of formic acid on the respiratory enzyme chain at the cytochrome oxidase level. Hypoxia and, as a consequence, a decrease in energy supply lead to a disruption of biological oxidation and the development of apoptosis in the optic nerve fibers. Understanding the process of optic nerve atrophy development at the pathogenetic level in methyl alcohol intoxication will help make a correct early diagnosis and prescribe timely treatment.

Long-term consequences of acute toxic prenatal hypoxia induced by sodium nitrite in rat experiments

Introduction. Gestational hypoxia plays an important role in fetal development, as it causes the development of oxidative stress and delayed psychomotor development. The aim of the study was to evaluate the prenatal effect of sodium nitrite on indices characterizing orienting and exploratory activity, mental activity and the degree of hypoxia in rat offspring. Materials and methods. Acute hypoxia was modeled by administration of sodium nitrite at a dose of 30 mg/kg intramuscularly to five pregnant rats during 16–19 days of gestation. Five females constituted a control group. In 50 born rats, orientation and exploration activity, cognitive functions, intensity of lipid peroxidation and glycolysis were studied. Results. The offspring of females that underwent acute hypoxia significantly lagged behind in the positive dynamics of body weight gain compared to control individuals. Thirty-day-old rats showed a pronounced disorder of the structure of behavioral pattern, learning process and long-term memory, increased content of diene conjugates, malonic dialdehyde and the level of lactate dehydrogenase activity in blood. Discussion. It was found that offspring whose mothers suffered acute hypoxia of toxic genesis developed pronounced behavioral disorders of psychomotor agitation and cognitive dysfunction characterized by decreased learning ability and impaired long-term memory. The content of primary and secondary products of lipid peroxidation and lactate dehydrogenase was increased in rats. The development of cellular oxidative stress under conditions of intrauterine hypoxia leads to oxygen deficiency in the fetus and a switch from tissue respiration to glycolysis, which underlies CNS damage. Conclusion. It was shown that sodium nitrite administration during the period from the 16th to the 19th day of gestation caused hyperactivity, depressed emotional status, and decreased orienting and exploratory activity and the ability to learn and retain a memory trace in rat offspring. Increased levels of diene conjugates and malonic dialdehyde, lactate dehydrogenase activity were observed in rats.

Noncoupled Mitochondrial Respiration as Therapeutic Approach for the Treatment of Metabolic Diseases: Focus on Transgenic Animal Models.

Mitochondrial dysfunction contributes to numerous chronic diseases, and mitochondria are targets for various toxins and xenobiotics. Therefore, the development of drugs or therapeutic strategies targeting mitochondria is an important task in modern medicine. It is well known that the primary, although not the sole, function of mitochondria is ATP generation, which is achieved by coupled respiration. However, a high membrane potential can lead to uncontrolled reactive oxygen species (ROS) production and associated dysfunction. For over 50 years, scientists have been studying various synthetic uncouplers, and for more than 30 years, uncoupling proteins that are responsible for uncoupled respiration in mitochondria. Additionally, the proteins of the mitochondrial alternative respiratory pathway exist in plant mitochondria, allowing noncoupled respiration, in which electron flow is not associated with membrane potential formation. Over the past two decades, advances in genetic engineering have facilitated the creation of various cellular and animal models that simulate the effects of uncoupled and noncoupled respiration in different tissues under various disease conditions. In this review, we summarize and discuss the findings obtained from these transgenic models. We focus on the advantages and limitations of transgenic organisms, the observed physiological and biochemical changes, and the therapeutic potential of uncoupled and noncoupled respiration.

Роль магнію в організмі здорової людини в перебігу і реабілітації після респіраторної інфекційної патології та COVID-19 (відомості літератури, власні дані)

Magnesium is a macroelement that plays an important role in the regulation of many physiological processes. In the case of insufficient intake of magnesium, which does not meet the needs of the child's body, its deficiency develops. Clinical manifestations of magnesium deficiency are nonspecific and may be similar to symptoms of various diseases, including asthenic syndrome. In turn, asthenic syndrome is common in children who have suffered infectious diseases, COVID-19, influenza, and other acute respiratory infectious pathology. In such children, excessive anxiety, rapid fatigue, sudden mood changes, sleep disorders, and emotional lability can be detected. Given that the leading role in ensuring the proper functioning of most of the body's enzyme systems, tissue respiration, energy exchange, and synthetic processes belongs to magnesium, it is assumed that the development of the described symptoms may be related to its deficiency. Purpose - to summarize literature data on the role of magnesium in the body of a healthy person, the peculiarities of its metabolism, its importance in the course and rehabilitation after respiratory infectious pathology and COVID-19, signs of deficiency, and methods of its correction; evaluate the results of own research. Materials and methods. General clinical (analysis of anamnesis data), laboratory (determination of magnesium level in blood serum), statistical, bibliographic, and information-analytic research methods were used. 60 children aged 9 to 18 took part in the study, among them 35 children who had COVID-19 (the first group) and 25 children who did not have COVID-19 (the second group). Results. It was established that the average value of magnesium level in blood serum in children of the first group was lower than in children of the second group (p=0.005). Individual analysis showed that 31.4% of patients in the first group, who had a term of 4-5 months after COVID-19, noted the presence of post-COVID-19 symptoms, such as excessive fatigue, headache, muscle weakness, impaired sleep, appetite, which coincides with the data of the literature. Conclusions. The data of our study may indicate the effect of transferred COVID-19 on the level of magnesium in the blood serum, which may be one of the reasons for its deficiency and, accordingly, the development of post-COVID-19 symptoms in children. It is advisable to carry out laboratory determination of the magnesium level in children who had acute respiratory infectious pathology, including COVID-19, to establish the causes of the development of individual symptoms that aggravate the general well-being, prevent the development of magnesium deficiency and find additional ways of rehabilitation after respiratory infectious pathology and COVID-19. No conflict of interests was declared by the authors.

A common East-Asian ALDH2 mutation causes metabolic disorders and the therapeutic effect of ALDH2 activators

Obesity and type 2 diabetes have reached pandemic proportion. ALDH2 (acetaldehyde dehydrogenase 2, mitochondrial) is the key metabolizing enzyme of acetaldehyde and other toxic aldehydes, such as 4-hydroxynonenal. A missense Glu504Lys mutation of the ALDH2 gene is prevalent in 560 million East Asians, resulting in reduced ALDH2 enzymatic activity. We find that male Aldh2 knock-in mice mimicking human Glu504Lys mutation were prone to develop diet-induced obesity, glucose intolerance, insulin resistance, and fatty liver due to reduced adaptive thermogenesis and energy expenditure. We find reduced activity of ALDH2 of the brown adipose tissue from the male Aldh2 homozygous knock-in mice. Proteomic analyses of the brown adipose tissue from the male Aldh2 knock-in mice identifies increased 4-hydroxynonenal-adducted proteins involved in mitochondrial fatty acid oxidation and electron transport chain, leading to markedly decreased fatty acid oxidation rate and mitochondrial respiration of brown adipose tissue, which is essential for adaptive thermogenesis and energy expenditure. AD-9308 is a water-soluble, potent, and highly selective ALDH2 activator. AD-9308 treatment ameliorates diet-induced obesity and fatty liver, and improves glucose homeostasis in both male Aldh2 wild-type and knock-in mice. Our data highlight the therapeutic potential of reducing toxic aldehyde levels by activating ALDH2 for metabolic diseases.

Adverse bioenergetic effects of N-acyl amino acids in human adipocytes overshadow beneficial mitochondrial uncoupling

ObjectiveEnhancing energy turnover via uncoupled mitochondrial respiration in adipose tissue has great potential to improve human obesity and other metabolic complications. However, the amount of human brown adipose tissue and its uncoupling protein 1 (UCP1) is low in obese patients. Recently, a class of endogenous molecules, N-acyl amino acids (NAAs), was identified as mitochondrial uncouplers in murine adipocytes, presumably acting via the adenine nucleotide translocator (ANT). Given the translational potential, we investigated the bioenergetic effects of NAAs in human adipocytes, characterizing beneficial and adverse effects, dose ranges, amino acid derivatives and underlying mechanisms. MethodNAAs with neutral (phenylalanine, leucine, isoleucine) and polar (lysine) residues were synthetized and assessed in intact and permeabilized human adipocytes using plate-based respirometry. The Seahorse technology was applied to measure bioenergetic parameters, dose-dependency, interference with UCP1 and adenine nucleotide translocase (ANT) activity, as well as differences to the established chemical uncouplers niclosamide ethanolamine (NEN) and 2,4-dinitrophenol (DNP). ResultNAAs with neutral amino acid residues potently induce uncoupled respiration in human adipocytes in a dose-dependent manner, even in the presence of the UCP1-inhibitor guanosine diphosphate (GDP) and the ANT-inhibitor carboxyatractylate (CAT). However, neutral NAAs significantly reduce maximal oxidation rates, mitochondrial ATP-production, coupling efficiency and reduce adipocyte viability at concentrations above 25 μM. The in vitro therapeutic index (using induced proton leak and viability as determinants) of NAAs is lower than that of NEN and DNP. ConclusionNAAs are potent mitochondrial uncouplers in human adipocytes, independent of UCP1 and ANT. However, previously unnoticed adverse effects harm adipocyte functionality, reduce the therapeutic index of NAAs in vitro and therefore question their suitability as anti-obesity agents without further chemical modifications.

Prolonged Endurance Exercise Increases Macrophage Content and Mitochondrial Respiration in Adipose Tissue in Trained Men.

The aim of this study was to investigate the effect of prolonged endurance exercise on adipose tissue inflammation markers and mitochondrial respiration in younger and older men. "Young" (aged 30 years, n = 7) and "old" (aged 65 years, n = 7) trained men were exposed to an exercise intervention of 15 consecutive days biking 7 to 9 hours/day at 63% and 65% of maximal heart rate (young and old, respectively), going from Copenhagen, Denmark to Palermo, Italy. Adipose tissue was sampled from both the gluteal and abdominal depot before and after the intervention. Mitochondrial respiration was measured by high-resolution respirometry, and adipose inflammation was assessed by immunohistochemical staining of paraffin embedded sections. An increased number of CD163+ macrophages was observed in both the gluteal and abdominal depot (P < .01). In addition, an increased mitochondrial respiration was observed in the abdominal adipose tissue from men in the young group with complex I (CIp) stimulated respiration, complex I + II (CI+IIp) stimulated respiration and the capacity of the electron transport system (ETS) (P < .05), and in the older group an increase in CIp and CI+IIp stimulated respiration (P < .05) was found. Overall, we found a positive effect of prolonged endurance exercise on adipose tissue inflammation markers and mitochondrial respiration in both young and old trained men, and no sign of attenuated function in adipose tissue with age.

Examination of the Microvasculature During Wound Process of the Oral Mucosa when Using Dual-Wavelength Photodynamic Therapy: a Pre-Clinical Experimental Randomized Study

Background. Healing of open wounds in the oral cavity is often accompanied by infection and constant traumatization, which lead to impaired blood supply to the tissues, lack of trophic support and low oxygen supply to increasing proliferative processes. Recently, photodynamic therapy has taken its place among the methods for stimulating regeneration of oral mucosal tissues. The authors consider it essential to study the influence of photodynamic treatment on the functional state of the microvasculature in the wound tissues, which determines the transcapillary exchange and the tissue respiration, providing the tissue regeneration.Objective. To study the photodynamic effect of sequential dual-wavelength radiation on the microvasculature in the wound tissues of the oral mucosa in vivo.Methods. The study was carried out on 36 female outbred Wistar rats, weighing 200–250 g. The animals were divided into two groups: control group (n = 18) and experimental group (n = 18). Wound surfaces healed by secondary intention were modeled on the cheek mucosa of the animals. Dual-wavelength photodynamic therapy was performed in the 1st postoperative day in experimental group. The microcirculatory function was assessed by Doppler flowmetry before, and on days 3, 7 and 14 after wounding. The results were processed using IBM SPSS Statistics 26.0.0.1 (IBM Inc., USA).Results. It has been established that dual-wavelength photodynamic therapy has a positive effect on the restoration of the microvasculature of the wound tissues. This therapy facilitated bypassing for microcirculatory flow on the 3rd day of the study, and increased the perfusion of tissues on the 7th. The experimental group did not have congestive-ischaemic phenomena in the wound region; the microcirculatory flow was augmented through the microcirculation regulation by the 14th day.Conclusion. Following the obtained results the use of dual-wavelength photodynamic therapy can be considered as a promising method for restoration of the microvasculature of tissues in the oral mucosal trauma.