Riboflavin Crystals with Extremely High Water Solubility.

New insights into the unique biochemical properties of riboflavin (Rf), also known as vitamin B2, are leading to the development of its use not only as a vitamin supplement but also as a potential anti-inflammatory, immunomodulatory, antioxidant, anticancer, and antiviral agent, where it may play a role as an inhibitor of viral proteinases. At the same time, the comparison of the pharmacoactivity of Rf with its known metabolites, namely, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), is very complicated due to its poor water solubility: 0.1-0.3 g/L versus 67 g/L for FMN and 50 g/L for FAD, which is the limiting factor for its administration in clinical practice. In this study, we report the recrystallization procedure of the type A Rf crystals into the slightly hydrophobic type B/C and a new hydrophilic crystal form that has been termed the P type. Our method of Rf crystal modification based on recrystallization from dilute alkaline solution provides an unprecedented extremely high water solubility of Rf, reaching 23.5 g/L. A comprehensive study of the physicochemical properties of type P riboflavin showed increased photodynamic therapeutic activity compared to the known types A and B/C against clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Salmonella typhimurium. Importantly, our work not only demonstrates a simple and inexpensive method for the synthesis of riboflavin with high solubility, which should lead to increased bioactivity, but also opens up opportunities for improving both known and new therapeutic applications of vitamin B2.

Mediating the performance of anaerobic granular sludge by exogenous flavin supplementation: Flavin binding capacity and behavior, interspecies electron transfer, and methane production.

Although flavins are known as effective electron mediators, the binding capacity of exogenous flavins by anaerobic granular sludge (AGS) and their role in interspecies electron transfer (IET) remains unknown. In this study, AGS was mediated by using three exogenous flavins of riboflavin (RF), flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD). Results showed that the total amounts of flavins associated with extracellular polymeric substance (EPS) of AGS increased by 2.03-2.42 and 3.83-4.94 folds, after exposure to 50 and 200 µM of exogenous flavins, respectively. A large portion of FMN and FAD was transformed into RF by AGS. Exogenous flavin mediation also stimulated the production of EPS and cytochrome c (c-Cyts) as well as cytochrome-bound flavins. The increased abundance of these electron mediators led to a reduced electrochemical impedance of EPS and improved extracellular electron transfer capacity. The methane production of AGS after mediation with exogenous RF, FMN, and FAD increased by 19.03-31.71%, 22.86-26.04%, and 28.51-33.44%, respectively. This study sheds new light on the role of exogenous flavins in promoting the IET process of a complex microbial aggregate of AGS.

Insight into the enhancing mechanism of exogenous electron mediators on biological denitrification in microbial electrolytic cell.

Sustained nitrate accumulation in surface water ecosystem was continuously grabbing public attention. Autotrophic denitrification by electron supplement has been applied to overcome the requirement of carbon source, thus the new problem that how to improve the efficiency of extracellular electrons transfer to denitrifiers comes to us. The addition of exogenous electron mediators has been considered as an important strategy to promote extracellular electrons transfer in reductive metabolism. To date, knowledge is lacking about the promoting effects and pathways in nitrate removal by electron mediators. Here, we fully investigated the performance of nitrogen removal as well as quantified the characteristics of biofilms with six electron mediators (riboflavin, flavin mononucleotide, AQS, AQDS, biochar and Nano-Fe3O4) treating in microbial electrolytic cell system. The six electron mediators promoted nitrate removal rate by 76.03-90.43 % with electron supplement. The growth and activity of cathodic biofilm, conductive nanowires generation and electrochemically active substance synthesis of extracellular polymeric substances were facilitated by electron mediator addition. Electrochemical analysis revealed that conductivity and redox capacity of cathodic biofilm was increased for accelerating electron transfer. Moreover, they upregulated the abundance of denitrifying communities and denitrifying genes accordingly. Their denitrification efficiency varied due to their promotion ability in the above different strategies and conductive characteristics, and the efficiency could be concluded as: Nano-Fe3O4 > riboflavin > flavin mononucleotide > AQS ≈ AQDS > biochar. This study revealed how addition of electron mediators promoted denitrification with electron supplement, and compared their promoting efficiency in several main aspects.

Construction of the advanced flavin mononucleotide producers in the flavinogenic yeast Candida famata.

Flavin mononucleotide (FMN, riboflavin-5'-phosphate) is flavin coenzyme synthesized in all living organisms from riboflavin (vitamin B2 ) after phosphorylation in the reaction catalyzed by riboflavin kinase. FMN has several applications mostly as yellow colorant in food industry due to 200 times better water solubility as compared to riboflavin. Currently, FMN is produced by chemical phosphorylation of riboflavin, however, final product contains up to 25% of flavin impurities. Microbial overproducers of FMN are known, however, they accumulate this coenzyme in glucose medium. Current work shows that the recombinant strains of the flavinogenic yeast Candida famata with overexpressed FMN1 gene coding for riboflavin kinase in the recently isolated by us advanced riboflavin producers due to overexpression of the structural and regulatory genes of riboflavin synthesis and of the putative exporter of riboflavin from the cell, synthesized elevated amounts of FMN in the media not only with glucose but also in lactose and cheese whey. Activation of FMN accumulation on lactose and cheese whey was especially strong in the strains which expressed the gene of transcription activator SEF1 under control of the lactose-induced LAC4 promoter. The accumulation of this coenzyme by the washed cells of the best recombinant strain achieved 540 mg/L in the cheese whey supplemented only with ammonium sulfate during 48 h in shake flask experiments.

Structural basis for the transformation of the traditional medicine berberine by bacterial nitroreductase.

The bacterial nitroreductases (NRs) NfsB and NfsA are conserved homodimeric FMN-dependent flavoproteins that are responsible for the reduction of nitroaromatic substrates. Berberine (BBR) is a plant-derived isoquinoline alkaloid with a large conjugated ring system that is widely used in the treatment of various diseases. It was recently found that the gut microbiota convert BBR into dihydroberberine (dhBBR, the absorbable form) mediated by bacterial NRs. The molecular basis for the transformation of BBR by the gut microbiota remains unclear. Here, kinetic studies showed that NfsB from Escherichia coli (EcNfsB), rather than EcNfsA, is responsible for the conversion of BBR to dhBBR in spite of a low reaction rate. The crystal structure of the EcNfsB-BBR complex showed that BBR binds into the active pocket at the dimer interface, and its large conjugated plane stacks above the plane of the FMN cofactor in a nearly parallel orientation. BBR is mainly stabilized by π-stacking interactions with both neighboring aromatic residues and FMN. Structure-based mutagenesis studies further revealed that the highly conserved Phe70 and Phe199 are important residues for the conversion of BBR. The structure revealed that the C6 atom of BBR (which receives the hydride) is ∼7.5 Šfrom the N5 atom of FMN (which donates the hydride), which is too distant for hydride transfer. Notably, several well ordered water molecules make hydrogen-bond/van der Waals contacts with the N1 atom of BBR in the active site, which probably donate protons in conjunction with electron transfer from FMN. The structure-function studies revealed the mechanism for the recognition and binding of BBR by bacterial NRs and may help to understand the conversion of BBR by the gut microbiota.

Vitamin B-6 and riboflavin, their metabolic interaction, and relationship with MTHFR genotype in adults aged 18-102 years.

BACKGROUND: The generation of the active form of vitamin B-6, pyridoxal 5'-phosphate (PLP), in tissues is dependent upon riboflavin as flavin mononucleotide, but whether this interaction is important for maintaining vitamin B-6 status is unclear. OBJECTIVE: To investigate vitamin B-6 and riboflavin status, their metabolic interaction, and relationship with methylenetetrahydrofolate reductase (MTHFR) genotype in adulthood. METHODS: Data from 5612 adults aged 18-102 y were drawn from the Irish National Adult Nutrition Survey (NANS; population-based sample) and the Trinity-Ulster Department of Agriculture (TUDA) and Genovit cohorts (volunteer samples). Plasma PLP and erythrocyte glutathione reductase activation coefficient (EGRac), as a functional indicator of riboflavin, were determined. RESULTS: Older (≥65 y) compared with younger (<65 y) adults had significantly lower PLP concentrations (P < 0.001). A stepwise decrease in plasma PLP was observed across riboflavin categories, from optimal (EGRac ≤1.26), to suboptimal (EGRac: 1.27-1.39), to deficient (EGRac ≥1.40) status, an effect most pronounced in older adults (mean ± SEM: 76.4 ± 0.9 vs 65.0 ± 1.1 vs 55.4 ± 1.2 nmol/L; P < 0.001). In individuals with the variant MTHFR 677TT genotype combined with riboflavin deficiency, compared with non-TT (CC/CT) genotype participants with sufficient riboflavin, we observed PLP concentrations of 52.1 ± 2.9 compared with 76.8 ±0.7 nmol/L (P < 0.001). In participants with available dietary data (i.e., NANS cohort, n = 936), PLP was associated with vitamin B-6 intake (nonstandardized regression coefficient ß: 2.49; 95% CI 1.75, 3.24; P < 0.001), supplement use (ß: 81.72; 95% CI: 66.01, 97.43; P < 0.001), fortified food (ß: 12.49; 95% CI: 2.08, 22.91; P = 0.019), and EGRac (ß: -65.81; 95% CI: -99.08, -32.54; P < 0.001), along with BMI (ß: -1.81; 95% CI: -3.31, -0.30; P = 0.019). CONCLUSIONS: These results are consistent with the known metabolic dependency of PLP on flavin mononucleotide (FMN) and suggest that riboflavin may be the limiting nutrient for maintaining vitamin B-6 status, particularly in individuals with the MTHFR 677TT genotype. Randomized trials are necessary to investigate the PLP response to riboflavin intervention within the dietary range. The TUDA study and the NANS are registered at www.ClinicalTrials.gov as NCT02664584 (27 January 2016) and NCT03374748 (15 December 2017), respectively.Clinical Trial Registry details: Trinity-Ulster-Department of Agriculture (TUDA) study, ClinicalTrials.gov no. NCT02664584 (January 27th 2016); National Adult Nutrition Survey (NANS), ClinicalTrials.gov no. NCT03374748 (December 15th 2017).

Covalent flavoproteins: types, occurrence, biogenesis and catalytic mechanisms.

Flavoproteins are proteins that contain a nucleic acid derivative of riboflavin: flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN). Flavoproteins are involved in a wide array of biological processes, such as photosynthesis, DNA repair and natural product biosynthesis. It should be noted that 5%-10% of flavoproteins have a covalently linked flavin prosthetic group. Such covalent linkages benefit the holoenzyme in several ways including improving the stability and catalytic potency. During the past decade, significant progress has been made in covalent flavoproteins, especially with respect to enzyme-dependent biogenesis and discovery of novel linkage types. The present review gives a condensed overview of investigations published from March 2009 to December 2021, with emphasis on the discovery, biogenesis and their catalytic role in natural product biosynthesis.

Cheese whey supports high riboflavin synthesis by the engineered strains of the flavinogenic yeast Candida famata.

BACKGROUND: Riboflavin is a precursor of FMN and FAD which act as coenzymes of numerous enzymes. Riboflavin is an important biotechnological commodity with annual market sales exceeding nine billion US dollars. It is used primarily as a component of feed premixes, a food colorant, a component of multivitamin mixtures and medicines. Currently, industrial riboflavin production uses the bacterium, Bacillus subtilis, and the filamentous fungus, Ashbya gossypii, and utilizes glucose and/or oils as carbon substrates. RESULTS: We studied riboflavin biosynthesis in the flavinogenic yeast Candida famata that is a genetically stable riboflavin overproducer. Here it was found that the wild type C. famata is characterized by robust growth on lactose and cheese whey and the engineered strains also overproduce riboflavin on whey. The riboflavin synthesis on whey was close to that obtained on glucose. To further enhance riboflavin production on whey, the gene of the transcription activator SEF1 was expressed under control of the lactose-induced promoter of the native ß-galactosidase gene LAC4. These transformants produced elevated amounts of riboflavin on lactose and especially on whey. The strain with additional overexpression of gene RIB6 involved in conversion of ribulose-5-phosphate to riboflavin precursor had the highest titer of accumulated riboflavin in flasks during cultivation on whey. Activation of riboflavin synthesis was also obtained after overexpression of the GND1 gene that is involved in the synthesis of the riboflavin precursor ribulose-5-phosphate. The best engineered strains accumulated 2.5 g of riboflavin/L on whey supplemented only with (NH4)2SO4 during batch cultivation in bioreactor with high yield (more than 300 mg/g dry cell weight). The use of concentrated whey inhibited growth of wild-type and engineered strains of C. famata, so the mutants tolerant to concentrated whey were isolated. CONCLUSIONS: Our data show that the waste of dairy industry is a promising substrate for riboflavin production by C. famata. Possibilities for using the engineered strains of C. famata to produce high-value commodity (riboflavin) from whey are discussed.

RibU is an essential determinant of Listeria pathogenesis that mediates acquisition of FMN and FAD during intracellular growth.

Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are essential riboflavin-derived cofactors involved in a myriad of redox reactions across all forms of life. Nevertheless, the basis of flavin acquisition strategies by riboflavin auxotrophic pathogens remains poorly defined. In this study, we examined how the facultative intracellular pathogen Listeria monocytogenes, a riboflavin auxotroph, acquires flavins during infection. A L. monocytogenes mutant lacking the putative riboflavin transporter (RibU) was completely avirulent in mice but had no detectable growth defect in nutrient-rich media. However, unlike wild type, the RibU mutant was unable to grow in defined media supplemented with FMN or FAD or to replicate in macrophages starved for riboflavin. Consistent with RibU functioning to scavenge FMN and FAD inside host cells, a mutant unable to convert riboflavin to FMN or FAD retained virulence and grew in cultured macrophages and in spleens and livers of infected mice. However, this FMN- and FAD-requiring strain was unable to grow in the gallbladder or intestines, where L. monocytogenes normally grows extracellularly, suggesting that these sites do not contain sufficient flavin cofactors to promote replication. Thus, by deleting genes required to synthesize FMN and FAD, we converted L. monocytogenes from a facultative to an obligate intracellular pathogen. Collectively, these data indicate that L. monocytogenes requires riboflavin to grow extracellularly in vivo but scavenges FMN and FAD to grow in host cells.

Inhibition of bacterial FMN transferase: A potential avenue for countering antimicrobial resistance.

Antibiotic resistance is a challenge for the control of bacterial infections. In an effort to explore unconventional avenues for antibacterial drug development, we focused on the FMN-transferase activity of the enzyme Ftp from the syphilis spirochete, Treponema pallidum (Ftp_Tp). This enzyme, which is only found in prokaryotes and trypanosomatids, post-translationally modifies proteins in the periplasm, covalently linking FMN (from FAD) to proteins that typically are important for establishing an essential electrochemical gradient across the cytoplasmic membrane. As such, Ftp inhibitors potentially represent a new class of antimicrobials. Previously, we showed that AMP is both a product of the Ftp_tp-catalyzed reaction and an inhibitor of the enzyme. As a preliminary step in exploiting this property to develop a novel Ftp_Tp inhibitor, we have used structural and solution studies to examine the inhibitory and enzyme-binding properties of several adenine-based nucleosides, with particular focus on the 2-position of the purine ring. Implications for future drug design are discussed.

[Development of an algorithm for the appointment of biofeed-back therapy and Cytoflavin for the treatment of osteochondrosis in elderly patients.]

Continuous improvement of protocols for the treatment of various ailments, in particular, osteochondrosis, is one of the important tasks of providing medical care to elderly patients. Supplementation of treatment with Cytoflavin and biofeed-back therapy seems to be a promising solution, however, it is necessary to develop an algorithm to predict it effectiveness in patients taking into account their initial clinical and psychophysiological status. As a result of the treatment, predictors of the effectiveness of the use of Cytoflavin and biofeed-back therapy have been identified and an algorithm for their administration has been developed.

Systemic Regulation of Host Energy and Oogenesis by Microbiome-Derived Mitochondrial Coenzymes.

Gut microbiota have been shown to promote oogenesis and fecundity, but the mechanistic basis of remote influence on oogenesis remained unknown. Here, we report a systemic mechanism of influence mediated by bacterial-derived supply of mitochondrial coenzymes. Removal of microbiota decreased mitochondrial activity and ATP levels in the whole-body and ovary, resulting in repressed oogenesis. Similar repression was caused by RNA-based knockdown of mitochondrial function in ovarian follicle cells. Reduced mitochondrial function in germ-free (GF) females was reversed by bacterial recolonization or supplementation of riboflavin, a precursor of FAD and FMN. Metabolomics analysis of GF females revealed a decrease in oxidative phosphorylation and FAD levels and an increase in metabolites that are degraded by FAD-dependent enzymes (e.g., amino and fatty acids). Riboflavin supplementation opposed this effect, elevating mitochondrial function, ATP, and oogenesis. These findings uncover a bacterial-mitochondrial axis of influence, linking gut bacteria with systemic regulation of host energy and reproduction.

Heterologous Expression and Characterization of Flavinadenine Dinucleotide Synthetase from Candida famata for Flavin Adenine Dinucleotide Production.

BACKGROUND: Flavin adenine dinucleotide (FAD) is a redox-active coenzyme that regulates several important enzymatic reactions during metabolism. FAD is used in the medicinal and food industries and FAD supplements have been used to treat some inheritable diseases. FAD can be biosynthesized from flavin mononucleotide (FMN) and adenosine triphosphate (ATP), catalyzed by FAD synthetase (FADS). OBJECTIVE: The aim of this study was to heterologously express the gene encoding FADS from the flavinogenic yeast Candida famata (FADSCf) for biosynthesis of FAD. METHODS: The sequence encoding FADSCf was retrieved and heterologously expressed in Escherichia coli. The structure and enzymatic properties of recombinant FADSCf were characterized. RESULTS: FADSCf (279 amino acids) was successfully expressed in E. coli BL21 (DE3), with a theoretical molecular weight of 32299.79 Da and an isoelectric point of 6.09. Secondary structural analysis showed that the number of α-helices was 2-fold higher than the number of ß-sheets, indicating that the protein was highly hydrophilic. Under fixed ATP concentration, FADSCf had a Km of 0.04737±0.03158 mM and a Vmax of 3.271±0.79 µM/min/mg. Under fixed FMN concentration, FADSCf had a Km of 0.1214±0.07464 mM and a Vmax of 2.6695±0.3715 µM/min/mg. Enzymatic reactions in vitro showed that expressed FADSCf could form 80 mM of FAD per mg of enzyme after 21 hours under the following conditions: 0.5 mM FMN, 5 mM ATP and 10 mM Mg2+. CONCLUSION: Under optimized conditions (0.5 mM FMN, 5 mM ATP and 10 mM Mg2+), the production of FAD reached 80 mM per mg of FADSCf after a 21-hour reaction. Our results indicate that purified recombinant FADSCf can be used for the biosynthesis of FAD.

Early predictive blood markers of hemorrhagic stroke - influence of cytoflavin therapy.

Examination of the patterns of free-radical processes (FRP) and changes of the early screening markers to predict the course of hemorrhagic stroke (HS) and applied pathophysiologically based therapy can be of great practical importance. This study aimed to determine early changes in the parameters of oxidative stress and routine biochemistry blood tests in patients with HS and to assess their relationship with clinical outcome. The effects of early applied cytoflavin were also investigated. The prospective study included 151 patients with HS. Forty-eight percent of patients in the standard conservative therapy were given cytoflavin antioxidant energy therapy from the first day of hospitalization. The neurological status, neuroimaging, biochemical blood tests and FRP were assessed on days 1, 5, 10, and 20 of hospitalization. In patients with HS, an imbalance of all stages of FRP was detected proportionately to the severity of HS. The malondialdehyde concentration above 5.3 µmol/L, the number of leukocytes above 15 800, glucose above 11.9 mmol/L, lactate dehydrogenase above 574 IU/L, and lactate above 2.5 mmol/L, detected on the first day, predetermined a high risk of death. Additional cytoflavin treatment allowed stabilizing the clinical laboratory picture of HS, improved the treatment results, and reduced hospital mortality rate.

Riboflavin Deficiency-Implications for General Human Health and Inborn Errors of Metabolism.

As an essential vitamin, the role of riboflavin in human diet and health is increasingly being highlighted. Insufficient dietary intake of riboflavin is often reported in nutritional surveys and population studies, even in non-developing countries with abundant sources of riboflavin-rich dietary products. A latent subclinical riboflavin deficiency can result in a significant clinical phenotype when combined with inborn genetic disturbances or environmental and physiological factors like infections, exercise, diet, aging and pregnancy. Riboflavin, and more importantly its derivatives, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), play a crucial role in essential cellular processes including mitochondrial energy metabolism, stress responses, vitamin and cofactor biogenesis, where they function as cofactors to ensure the catalytic activity and folding/stability of flavoenzymes. Numerous inborn errors of flavin metabolism and flavoenzyme function have been described, and supplementation with riboflavin has in many cases been shown to be lifesaving or to mitigate symptoms. This review discusses the environmental, physiological and genetic factors that affect cellular riboflavin status. We describe the crucial role of riboflavin for general human health, and the clear benefits of riboflavin treatment in patients with inborn errors of metabolism.

FMN reduces Amyloid-ß toxicity in yeast by regulating redox status and cellular metabolism.

Alzheimer's disease (AD) is defined by progressive neurodegeneration, with oligomerization and aggregation of amyloid-ß peptides (Aß) playing a pivotal role in its pathogenesis. In recent years, the yeast Saccharomyces cerevisiae has been successfully used to clarify the roles of different human proteins involved in neurodegeneration. Here, we report a genome-wide synthetic genetic interaction array to identify toxicity modifiers of Aß42, using yeast as the model organism. We find that FMN1, the gene encoding riboflavin kinase, and its metabolic product flavin mononucleotide (FMN) reduce Aß42 toxicity. Classic experimental analyses combined with RNAseq show the effects of FMN supplementation to include reducing misfolded protein load, altering cellular metabolism, increasing NADH/(NADH + NAD+) and NADPH/(NADPH + NADP+) ratios and increasing resistance to oxidative stress. Additionally, FMN supplementation modifies Htt103QP toxicity and α-synuclein toxicity in the humanized yeast. Our findings offer insights for reducing cytotoxicity of Aß42, and potentially other misfolded proteins, via FMN-dependent cellular pathways.

[SUBSTANTIATION OF INDICATIONS FOR BIOFEEDBACK THERAPY AND CYTOFLAVIN APPLICATION IN TREATMENT OF OSTEOCHONDROSIS NEUROLOGICAL COMPLICATIONS IN ELDERLY PATIENTS].

The aim of the study was to assess the impact of cytoflavin and bioflavin therapy on the dynamics of clinical and psychophysiological status of patients with Osteochondrosis. 150 patients with osteochondrosis of a backbone were investigated. The patients were divided into two groups using method of randomization: the main group - 75 patients - and control group -75 patients. All patients received a standard treatment (non-steroidal anti-inflammatory drugs, myorelaxants, chondroprotectors, as well as physiotherapy). The main group in addition to standard treatment received biofeedback therapy and cytoflavin. The results showed that cytoflavin and biofeedback therapy significantly enhanced the positive effect of standard treatment and significantly increased the quality of life of patients. It is recommended to treat elderly patients with neurological complications of spinal osteochondrosis with Cytoflavin in combination with biofeedback therapy Before prescribing biofeedback therapy and Cytoflavin it is necessary to take into account a number of positive and negative predictors of their effectiveness in reducing severity of pain syndrome.

[Prevention of cognitive dysfunction in elderly cancer patients operated on the pelvic organs in conditions of multimodal anesthesia]. / Profilaktika kognitivnoi disfunktsii u pozhilykh onkologicheskikh bol'nykh, operirovannykh na organakh malogo taza v usloviiakh mul'timodal'noi anestezii.

The aim of the study was to evaluate the impact of various variants of multimodal anesthesia on the cognitive functions of elderly patients after surgical interventions on pelvic organs, the development of preventive measures for POCD. MATERIAL AND METHODS: A study was conducted in 76 elderly patients aged 62 to 84 years with an increased risk of developing POCD. Of these, 46 women and 30 men. Patients were divided into two groups, depending on the type of anesthesia. The 1st group consisted of 37 patients who had low-flow anesthesia with sevoflurane combined with epidural analgesia. 2nd - 39 patients who had anticipated multimodal analgesia on the basis of systemic administration of lidocaine, sulphate magnesia, verapamil. In each group, patients are divided into subgroups - the main (O) and control (K). In the main subgroups anesthetics were supplemented with 20 ml. Cytoflavin, administered 20-25 minutes before the end of surgery and on the 1-3 days of the perioperative period. Cognitive functions were assessed by standardized scales: Mini Mental State Examination (MMSE), Montreal Cognitive Evaluation Scale (MoCA), Frontal Assessment Batteries (FAB). The level of anxiety and depression was determined by the hospital scale of anxiety and depression (HADS). RESULTS: At oncological patients of advanced age in 52.5% of cases there is a moderate degree of cognitive impairment. In the perioperative period, in the study groups, when using different variants of multimodal anesthesia, there is an equivalent transient decrease in cognitive functions by 12.5 and 12.8%. The use of cytoflavin can reduce the manifestation of POCD from 1-day perioperative period, improve the cognitive status of patients. CONCLUSION: In cancer patients of advanced age, cognitive impairment is observed, aggravated after surgical treatment, regardless of the variant of multimodal anesthesia. Protection by Cytoflavin allows to restore the cognitive functions of elderly cancer patients, reduce the manifestations of POCD.

[Modern approaches to components of therapy of patients with diabetes mellitus operated on for malignant neoplasms of small pelvic organs]. / Sovremennye podkhody k komponentam terapii bol'nykh sakharnym diabetom, operiruemykh po povodu zlokachestvennykh novoobrazovanii organov malogo taza.

The purpose of this study was assessment of the effect of cytoflavin preparation inclusion in surgical treatment of patients with malignant neoplasms of small pelvic organs and diabetes mellitus. A prospective examination of 51 patients aged 56 to 76 years suffering from diabetes mellitus and malignant neoplasms of the pelvic organs was performed. Patients were divided into two groups: the first group consisted of 27 patients whose adaptive potential was characterized by tension of adaptation mechanisms, the second one - 24 patients with poor adaptation. In turn, in each group, patients were divided into subgroups depending on the treatment regimen: in the main subgroup of the first group (14 people) the treatment program was supplemented with cytoflavin (10 ml 2 times a day), in the main subgroup of the second group were 13 patients with cytoflavin supplement (20 ml 2 times a day). Patients of control groups underwent standard therapy. State of energy deficiency was assessed by methemoglobin, carbohemoglobin, P50, oxygen delivery, consumption and extraction. Concentration of glucose, lactate, lactate dehydrogenase was assessed. The results of the study showed clear relationship between the nature of changes in transport and oxygen consumption, adaptation adaptive reactions, allowing to identify mechanisms that characterize formation of various types of energy deficiency in perioperative period in patients with malignant diseases of the pelvic organs and diabetes. Use of cytoflavin contributed to a qualitative and effective correction of energy deficiency as well as reduction in the patients stay in the hospital.

Critical Role of Flavin and Glutathione in Complex I-Mediated Bioenergetic Failure in Brain Ischemia/Reperfusion Injury.

BACKGROUND AND PURPOSE: Ischemic brain injury is characterized by 2 temporally distinct but interrelated phases: ischemia (primary energy failure) and reperfusion (secondary energy failure). Loss of cerebral blood flow leads to decreased oxygen levels and energy crisis in the ischemic area, initiating a sequence of pathophysiological events that after reoxygenation lead to ischemia/reperfusion (I/R) brain damage. Mitochondrial impairment and oxidative stress are known to be early events in I/R injury. However, the biochemical mechanisms of mitochondria damage in I/R are not completely understood. METHODS: We used a mouse model of transient focal cerebral ischemia to investigate acute I/R-induced changes of mitochondrial function, focusing on mechanisms of primary and secondary energy failure. RESULTS: Ischemia induced a reversible loss of flavin mononucleotide from mitochondrial complex I leading to a transient decrease in its enzymatic activity, which is rapidly reversed on reoxygenation. Reestablishing blood flow led to a reversible oxidative modification of mitochondrial complex I thiol residues and inhibition of the enzyme. Administration of glutathione-ethyl ester at the onset of reperfusion prevented the decline of complex I activity and was associated with smaller infarct size and improved neurological outcome, suggesting that decreased oxidation of complex I thiols during I/R-induced oxidative stress may contribute to the neuroprotective effect of glutathione ester. CONCLUSIONS: Our results unveil a key role of mitochondrial complex I in the development of I/R brain injury and provide the mechanistic basis for the well-established mitochondrial dysfunction caused by I/R. Targeting the functional integrity of complex I in the early phase of reperfusion may provide a novel therapeutic strategy to prevent tissue injury after stroke.