Collagen Matrix to Restore the Tympanic Membrane: Developing a Novel Platform to Treat Perforations.

Modern otology faces challenges in treating tympanic membrane (TM) perforations. Instead of surgical intervention, alternative treatments using biomaterials are emerging. Recently, we developed a robust collagen membrane using semipermeable barrier-assisted electrophoretic deposition (SBA-EPD). In this study, a collagen graft shaped like a sponge through SBA-EPD was used to treat acute and chronic TM perforations in a chinchilla model. A total of 24 ears from 12 adult male chinchillas were used in the study. They were organized into four groups. The first two groups had acute TM perforations and the last two had chronic TM perforations. We used the first and third groups as controls, meaning they did not receive the implant treatment. The second and fourth groups, however, were treated with the collagen graft implant. Otoscopic assessments were conducted on days 14 and 35, with histological evaluations and TM vibrational studies performed on day 35. The groups treated with the collagen graft showed fewer inflammatory changes, improved structural recovery, and nearly normal TM vibrational properties compared to the controls. The porous collagen scaffold successfully enhanced TM regeneration, showing high biocompatibility and biodegradation potential. These findings could pave the way for clinical trials and present a new approach for treating TM perforations.

Effects of the Long-Term Administration of Uridine on the Functioning of Rat Liver Mitochondria in Hyperthyroidism.

The effect of uridine (30 mg/kg for 7 days; intraperitoneally) on the functions of liver mitochondria in rats with experimentally induced hyperthyroidism (HT) (200 µg/100 g for 7 days, intraperitoneally) is studied in this paper. An excess of thyroid hormones (THs) led to an intensification of energy metabolism, the development of oxidative stress, a significant increase in the biogenesis, and changes in the content of proteins responsible for the fusion and fission of mitochondria. The injection of uridine did not change the concentration of THs in the blood of hyperthyroid rats (HRs) but normalized their body weight. The exposure to uridine improved the parameters of oxidative phosphorylation and corrected the activity of some complexes of the electron transport chain (ETC) in the liver mitochondria of HRs. The analysis of ETC complexes showed that the level of CI-CV did not change by the action of uridine in rats with the condition of HT. The application of uridine caused a significant increase in the activity of superoxide dismutase and lowered the rate of hydrogen peroxide production. It was found that uridine affected mitochondrial biogenesis by increasing the expression of the genes Ppargc1a and NRF1 and diminishing the expression of the Parkin gene responsible for mitophagy compared with the control animals. In addition, the mRNA level of the OPA1 gene was restored, which may indicate an improvement in the ETC activity and oxidative phosphorylation in the mitochondria of HR. As a whole, the results obtained demonstrate that uridine has a protective effect against HT-mediated functional disorders in the metabolism of rat liver mitochondria.

Warm Cells, Hot Mitochondria: Achievements and Problems of Ultralocal Thermometry.

Temperature is a crucial regulator of the rate and direction of biochemical reactions and cell processes. The recent data indicating the presence of local thermal gradients associated with the sites of high-rate thermogenesis, on the one hand, demonstrate the possibility for the existence of "thermal signaling" in a cell and, on the other, are criticized on the basis of thermodynamic calculations and models. Here, we review the main thermometric techniques and sensors developed for the determination of temperature inside living cells and diverse intracellular compartments. A comparative analysis is conducted of the results obtained using these methods for the cytosol, nucleus, endo-/sarcoplasmic reticulum, and mitochondria, as well as their biological consistency. Special attention is given to the limitations, possible sources of errors and ambiguities of the sensor's responses. The issue of biological temperature limits in cells and organelles is considered. It is concluded that the elaboration of experimental protocols for ultralocal temperature measurements that take into account both the characteristics of biological systems, as well as the properties and limitations of each type of sensor is of critical importance for the generation of reliable results and further progress in this field.

Vocal fold restoration after scarring: biocompatibility and efficacy of an MSC-based bioequivalent.

BACKGROUND: There is growing interest to application of regenerative medicine approaches in otorhinolaryngological practice, especially in the framework of the therapy of vocal fold (VF) scar lesions. The used conservative and surgical methods, despite the achieved positive outcomes, are frequently unpredictable and do not result in the restoration of the VF's lamina propria's structure, which provides the mechanical properties necessary for vibration. In this connection, the aim of this study was to ascertain the safety and efficacy of a bioequivalent in the treatment of VF scars using a rabbit model of chronic damage. METHODS: The bioequivalent consisted of a hydrogel system based on a PEG-fibrin conjugate and human bone marrow-derived MSC. It was characterized and implanted heterotopically into rats and orthotopically into rabbits after VF scar excision. RESULTS: We showed that the fabricated bioequivalent consisted of viable cells retaining their metabolic and proliferative activity. While being implanted heterotopically, it had induced the low inflammatory reaction in 7 days and was well tolerated. The orthotopic implantation showed that the gel application was characterized by a lower hemorrhage intensity (p = 0.03945). The intensity of stridor and respiratory rate between the groups in total and between separate groups had no statistically significant difference (p = 0.96 and p = 1; p = 0.9593 and p = 0.97…1, respectively). In 3 days post-implantation, MSC were detected only in the tissues closely surrounding the VF defect. The bioequivalent injection caused that the scar collagen fibers were packed looser and more frequently mutually parallel that is inherent in the native tissue (p = 0.018). In all experimental groups, the fibrous tissue's ingrowth in the adjacent exterior muscle tissue was observed; however, in Group 4 (PEG-Fibrin + MSC), it was much less pronounced than it was in Group 1 (normal saline) (p = 0.008). The difference between the thicknesses of the lamina propria in the control group and in Group 4 was not revealed to be statistically significant (p = 0.995). The Young's modulus of the VF after the bioequivalent implantation (1.15 ± 0.25 kPa) did not statistically significantly differ from the intact VF modulus (1.17 ± 0.45 kPa); therefore, the tissue properties in this group more closely resembled the intact VF. CONCLUSIONS: The developed bioequivalent showed to be biocompatible and highly efficient in the restoration of VF's tissue.

Mitochondrial F-ATP Synthase Co-Migrating Proteins and Ca2+-Dependent Formation of Large Channels.

Monomers, dimers, and individual FOF1-ATP synthase subunits are, presumably, involved in the formation of the mitochondrial permeability transition pore (PTP), whose molecular structure, however, is still unknown. We hypothesized that, during the Ca2+-dependent assembly of a PTP complex, the F-ATP synthase (subunits) recruits mitochondrial proteins that do not interact or weakly interact with the F-ATP synthase under normal conditions. Therefore, we examined whether the PTP opening in mitochondria before the separation of supercomplexes via BN-PAGE will increase the channel stability and channel-forming capacity of isolated F-ATP synthase dimers and monomers in planar lipid membranes. Additionally, we studied the specific activity and the protein composition of F-ATP synthase dimers and monomers from rat liver and heart mitochondria before and after PTP opening. Against our expectations, preliminary PTP opening dramatically suppressed the high-conductance channel activity of F-ATP synthase dimers and monomers and decreased their specific "in-gel" activity. The decline in the channel-forming activity correlated with the reduced levels of as few as two proteins in the bands: methylmalonate-semialdehyde dehydrogenase and prohibitin 2. These results indicate that proteins co-migrating with the F-ATP synthase may be important players in PTP formation and stabilization.

Regulation of Mitochondrial Permeability Transition Pore Opening by Monovalent Cations in Liver Mitochondria.

The opening of the permeability transition pore (PTP) in mitochondria is a key event in the initiation of cell death in various pathologic states, including ischemia/reperfusion. The activation of K+ transport into mitochondria protects cells from ischemia/reperfusion. However, the role of K+ transport in PTP regulation is unclear. Here, we studied the role of K+ and other monovalent cations in the regulation of the PTP opening in an in vitro model. The registration of the PTP opening, membrane potential, Ca2+-retention capacity, matrix pH, and K+ transport was performed using standard spectral and electrode techniques. We found that the presence of all cations tested in the medium (K+, Na+, choline+, and Li+) strongly stimulated the PTP opening compared with sucrose. Several possible reasons for this were examined: the effect of ionic strength, the influx of cations through selective and non-selective channels and exchangers, the suppression of Ca2+/H+ exchange, and the influx of anions. The data obtained indicate that the mechanism of PTP stimulation by cations includes the suppression of K+/H+ exchange and acidification of the matrix, which facilitates the influx of phosphate. Thus, the K+/H+ exchanger and the phosphate carrier together with selective K+ channels compose a PTP regulatory triad, which might operate in vivo.

Amyloid Aß25-35 Aggregates Say 'NO' to Long-Term Potentiation in the Hippocampus through Activation of Stress-Induced Phosphatase 1 and Mitochondrial Na+/Ca2+ Exchanger.

The search for strategies for strengthening the synaptic efficiency in Aß25-35-treated slices is a challenge for the compensation of amyloidosis-related pathologies. Here, we used the recording of field excitatory postsynaptic potentials (fEPSPs), nitric oxide (NO) imaging, measurements of serine/threonine protein phosphatase (STPP) activity, and the detection of the functional mitochondrial parameters in suspension of brain mitochondria to study the Aß25-35-associated signaling in the hippocampus. Aß25-35 aggregates shifted the kinase-phosphatase balance during the long-term potentiation (LTP) induction in the enhancement of STPP activity. The PP1/PP2A inhibitor, okadaic acid, but not the PP2B blocker, cyclosporin A, prevented Aß25-35-dependent LTP suppression for both simultaneous and delayed enzyme blockade protocols. STPP activity in the Aß25-35-treated slices was upregulated, which is reverted relative to the control values in the presence of PP1/PP2A but not in the presence of the PP2B blocker. A selective inhibitor of stress-induced PP1α, sephin1, but not of the PP2A blocker, cantharidin, is crucial for Aß25-35-mediated LTP suppression prevention. A mitochondrial Na+/Ca2+ exchanger (mNCX) blocker, CGP37157, also attenuated the Aß25-35-induced LTP decline. Aß25-35 aggregates did not change the mitochondrial transmembrane potential or reactive oxygen species (ROS) production but affected the ion transport and Ca2+-dependent swelling of organelles. The staining of hippocampal slices with NO-sensitive fluorescence dye, DAF-FM, showed stimulation of the NO production in the Aß25-35-pretreated slices at the dendrite-containing regions of CA1 and CA3, in the dentate gyrus (DG), and in the CA1/DG somata. NO scavenger, PTIO, or nNOS blockade by selective inhibitor 3Br-7NI partly restored the Aß25-35-induced LTP decline. Thus, hippocampal NO production could be another marker for the impairment of synaptic plasticity in amyloidosis-related states, and kinase-phosphatase balance management could be a promising strategy for the compensation of Aß25-35-driven deteriorations.

Plant Polysaccharide Array for Studying Carbohydrate-Binding Proteins.

The specificity of the most plant carbohydrate-binding proteins (CBP), many of which are known only through bioinformatic analysis of the genome, has either not been studied at all or characterized to a limited extent. The task of deciphering the carbohydrate specificity of the proteins can be solved using glycoarrays composed of many tens or even hundreds of glycans immobilized on a glass surface. Plant carbohydrates are the most significant natural ligands for plant proteins; this work shows that plant polysaccharides without additional modification can be immobilized on the surface, bearing N-hydroxysuccinimide activated carboxyl groups. As a result, an array of 113 well-characterized polysaccharides isolated from various plant cell walls, 23 mono- and oligosaccharides - components of polysaccharides, and glycans - ligands for widely known plant lectins was designed. Upon chemical immobilization of polysaccharides, their functional activity was preserved, which was confirmed by the results of interaction with antibodies and the plant lectin ricin. Using the constructed array, a previously unknown ability of ricin to bind polysaccharides was found, which significantly expands the knowledge of its specificity, and it was also found that a large variety of antibodies to plant polysaccharides are present in human peripheral blood.

Stem cell therapy for vocal fold regeneration after scarring: a review of experimental approaches.

This review aims at becoming a guide which will help to plan the experimental design and to choose adequate methods to assess the outcomes when testing cell-based products in the treatment of the damaged vocal folds. The requirements to preclinical trials of cell-based products remain rather hazy and dictated by the country regulations. Most parameters like the way the cells are administered, selection of the cell source, selection of a carrier, and design of in vivo studies are decided upon by each research team and may differ essentially between studies. The review covers the methodological aspects of preclinical studies such as experimental models, characterization of cell products, assessment of the study outcome using molecular, morphological and immunohistochemical analyses, as well as measuring the tissue physical properties. The unified recommendations to perform preclinical trials could significantly facilitate the translation of cell-based products into the clinical practice.

Functional State of Rat Heart Mitochondria in Experimental Hyperthyroidism.

In this work, the effect of thyroxine on energy and oxidative metabolism in the mitochondria of the rat heart was studied. Hyperthyroidism was observed in experimental animals after chronic administration of T4, which was accompanied by an increase in serum concentrations of free triiodothyronine (T3) and thyroxine (T4) by 1.8 and 3.4 times, respectively. The hyperthyroid rats (HR) had hypertrophy of the heart. In HR, there was a change in the oxygen consumption in the mitochondria of the heart, especially when using palmitoylcarnitine. The assay of respiratory chain enzymes revealed that the activities of complexes I, I + III, III, IV increased, whereas the activities of complexes II, II + III decreased in heart mitochondria of the experimental animals. It was shown that the level of respiratory complexes of the electron transport chain in hyperthyroid rats increased, except for complex V, the quantity of which was reduced. The development of oxidative stress in HR was observed: an increase in the hydrogen peroxide production rate, increase in lipid peroxidation and reduced glutathione. The activity of superoxide dismutase in the heart of HR was higher than in the control. At the same time, the activity of glutathione peroxidase decreased. The obtained data indicate that increased concentrations of thyroid hormones lead to changes in energy metabolism and the development of oxidative stress in the heart of rats, which in turn contributes to heart dysfunction.

Pioglitazone Is a Mild Carrier-Dependent Uncoupler of Oxidative Phosphorylation and a Modulator of Mitochondrial Permeability Transition.

Pioglitazone (PIO) is an insulin-sensitizing antidiabetic drug, which normalizes glucose and lipid metabolism but may provoke heart and liver failure and chronic kidney diseases. Both therapeutic and adverse effects of PIO can be accomplished through mitochondrial targets. Here, we explored the capability of PIO to modulate the mitochondrial membrane potential (ΔΨm) and the permeability transition pore (mPTP) opening in different models in vitro. ΔΨm was measured using tetraphenylphosphonium and the fluorescent dye rhodamine 123. The coupling of oxidative phosphorylation was estimated polarographically. The transport of ions and solutes across membranes was registered by potentiometric and spectral techniques. We found that PIO decreased ΔΨm in isolated mitochondria and intact thymocytes and the efficiency of ADP phosphorylation, particularly after the addition of Ca2+. The presence of the cytosolic fraction mitigated mitochondrial depolarization but made it sustained. Carboxyatractyloside diminished the PIO-dependent depolarization. PIO activated proton transport in deenergized mitochondria but not in artificial phospholipid vesicles. PIO had no effect on K+ and Ca2+ inward transport but drastically decreased the mitochondrial Ca2+-retention capacity and protective effects of adenine nucleotides against mPTP opening. Thus, PIO is a mild, partly ATP/ADP-translocase-dependent, uncoupler and a modulator of ATP production and mPTP sensitivity to Ca2+ and adenine nucleotides. These properties contribute to both therapeutic and adverse effects of PIO.

NAD(H) Regulates the Permeability Transition Pore in Mitochondria through an External Site.

The opening of the permeability transition pore (mPTP) in mitochondria initiates cell death in numerous diseases. The regulation of mPTP by NAD(H) in the mitochondrial matrix is well established; however, the role of extramitochondrial (cytosolic) NAD(H) is still unclear. We studied the effect of added NADH and NAD+ on: (1) the Ca2+-retention capacity (CRC) of isolated rat liver, heart, and brain mitochondria; (2) the Ca2+-dependent mitochondrial swelling in media whose particles can (KCl) or cannot (sucrose) be extruded from the matrix by mitochondrial carriers; (3) the Ca2+-dependent mitochondrial depolarization and the release of entrapped calcein from mitochondria of permeabilized hepatocytes; and (4) the Ca2+-dependent mitochondrial depolarization and subsequent repolarization. NADH and NAD+ increased the CRC of liver, heart, and brain mitochondria 1.5-2.5 times, insignificantly affecting the rate of Ca2+-uptake and the free Ca2+ concentration in the medium. NAD(H) suppressed the Ca2+-dependent mitochondrial swelling both in KCl- and sucrose-based media but did not induce the contraction and repolarization of swollen mitochondria. By contrast, EGTA caused mitochondrial repolarization in both media and the contraction in KCl-based medium only. NAD(H) delayed the Ca2+-dependent depolarization and the release of calcein from individual mitochondria in hepatocytes. These data unambiguously demonstrate the existence of an external NAD(H)-dependent site of mPTP regulation.

Dynamics of the permeability transition pore size in isolated mitochondria and mitoplasts.

The size of the permeability transition pore (PTP) is accepted to be ≤1.5 kDa. However, different authors reported values from 650 to 4000 Da. The present study is focused on the variability of the average PTP size in and between mitochondrial samples, its reasons and relations with PTP dynamics. Measurement of PTP size by the standard method revealed its 500 Da-range variability between mitochondrial samples. Sequential measurements in the same sample showed that the PTP size tends to grow with time and Ca2+ concentration. Selective damage to the mitochondrial outer membrane (MOM) reduced the apparent PTP size by ~200-300 Da. Hypotonic and hypertonic osmotic shock and partial removal of the MOM with the preservation of the mitochondrial inner membrane intactness decreased the apparent PTP size by ~50%. We developed an approach to continuous monitoring of the PTP size that revealed the existence of stable PTP states with different pore sizes (~700, 900-1000, ~1350, 1700-1800, and 2100-2200 Da) and transitions between them. The transitions were accelerated by elevating the Ca2+ concentration, temperature, and osmotic pressure, which demonstrates an increased capability of PTP to accommodate to large molecules (plasticity). Cyclosporin A inhibited the transitions between states. The analysis of PTP size dynamics in osmotically shocked mitochondria and mitoplasts confirmed the importance of the MOM for the stabilization of PTP structure. Thus, this approach provides a new tool for PTP studies and the opportunity to reconcile data on the PTP size and mitochondrial megachannel conductance.

Fatty acid composition of salted and fermented products from Baikal omul (Coregonus autumnalis migratorius).

The fatty acid (FA) composition of raw, salted, and fermented fish products prepared from two populations of Baikal omul (Coregonus autumnalis migratorius) was determined. Total lipid content in the raw, salted, and fermented fish products was 3.85, 4.04, and 3.76%, respectively. Overall, the most abundant fatty acids were 14:0 (myristic acid), 16:0 (palmitic acid), 16:1n-7 (palmitoleic acid), 18:1n-9 (oleic acid), 20:5n-3 (eicosapentaenoic acid), and 22:6n-3 (docosahexaenoic acid, DHA). Polyunsaturated FAs were the main fatty acid group. Among unsaturated FA, n-3 forms dominated. The highest amounts of n-3 FAs were found in raw fish, followed by fermented and salted fish. Salting significantly increased the content of some FAs (15:0, 16:2n-4, 18:3n-3, 20:3n-3) compared with raw fish and decreased the DHA content. The FA composition of fermented fish did not differ from that of raw fish. The n-3:n-6 ratio did not differ between raw, salted, and fermented fish from population A, while the ratio was higher in raw fish from population B. Overall, thiobarbituric acid reactive substances, and thereby oxidation, were significantly lower in raw fish than in salted and fermented fish. Salting, but not fermentation, affected the FA composition of fish.

Regulation of mitochondria function by natriuretic peptides.

Natriuretic peptides (NPs) are well known to promote renal Na+ excretion, counteracting the effects of the renin-angiotensin-aldosterone system. Thus, NPs serve as a key component in the maintenance of blood pressure, influencing fluid retention capabilities via osmoregulation. Recently, NPs have been shown to affect lipolysis and enhance lipid oxidation and mitochondrial respiration. Here, we provide an overview of current knowledge about the relationship between NPs and mitochondria-mediated processes such as reactive oxygen species production, Ca2+ signaling, and apoptosis. Establishing a clear physiological and mechanistic connection between NPs and mitochondria in the cardiovascular system will open new avenues of research aimed at understanding and potentially using it as a therapeutic target from a completely new angle.

Regulation of permeability transition pore opening in mitochondria by external NAD(H).

BACKGROUND: The opening of the permeability transition pore (PTP) in mitochondria plays a critical role in the pathogenesis of numerous diseases. Mitochondrial matrix pyridine nucleotides are potent regulators of the PTP, but the role of extramitochondrial nucleotides is unclear. METHODS: The PTP opening was explored in isolated mitochondria and mitochondria in permeabilized differentiated and undifferentiated cells in the presence of added NAD(P)(H) in combination with Mg2+, adenine nucleotides (AN), and the inhibitors of AN translocase (ANT), voltage-dependent anion channel (VDAC), and cyclophilin D. RESULTS: Added NAD(H) and AN, but not NADP(H), inhibited the PTP opening with comparable potency. PTP suppression required neither NAD(H) oxidation nor reduction. The protective effects of NAD(H) and cyclosporin A were synergistic, and the effects of NAD(H) and millimolar AN were additive. The conformation-specific ANT inhibitors were unable to cancel the protective effect of NADH even under total ANT inhibition. Besides, NAD(H) activated the efflux of mitochondrial AN via ANT. VDAC ligand (Mg2+) and blockers (G3139 and 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid) potentiated and attenuated the protective effect of NAD(H), respectively. However, in embryonic and cancer (undifferentiated) cells, in contrast to isolated differentiated hepatocytes and cardiocytes, the suppression of PTP opening by NADH was negligible though all cells tested possessed a full set of VDAC isoforms. CONCLUSIONS: The study revealed a novel mechanism of PTP regulation by external (cytosolic) NAD(H) through the allosteric site in the OM or the intermembrane space. GENERAL SIGNIFICANCE: The mechanism might contribute to the resistance of differentiated cells under different pathological conditions including ischemia/reperfusion.

Renal Glomerular Mitochondria Function in Salt-Sensitive Hypertension.

Salt-sensitive (SS) hypertension is accompanied with an early onset of proteinuria, which results from the loss of glomerular podocytes. Here, we hypothesized that glomerular damage in the SS hypertension occurs in part due to mitochondria dysfunction, and we used a unique model of freshly isolated glomeruli to test this hypothesis. In order to mimic SS hypertension, we used Dahl SS rats, an established animal model. Animals were fed a 0.4% NaCl (normal salt, NS) diet or challenged with a high salt (HS) 4% NaCl diet for 21 days to induce an increase in blood pressure (BP). Similar to previous studies, we found that HS diet caused renal hypertrophy, increased BP, glomerulosclerosis, and renal lesions such as fibrosis and protein casts. We did not observe changes in mitochondrial biogenesis in the renal cortex or isolated glomeruli fractions. However, Seahorse assay performed on freshly isolated glomeruli revealed that basal mitochondrial respiration, maximal respiration, and spare respiratory capacity were lower in the HS compared to the NS group. Using confocal imaging and staining for mitochondrial H2O2 using mitoPY1, we detected an intensified response to an acute H2O2 application in the podocytes of the glomeruli isolated from the HS diet fed group. TEM analysis showed that glomerular mitochondria from the HS diet fed group have structural abnormalities (swelling, enlargement, less defined cristae). Therefore, we report that glomerular mitochondria in SS hypertension are functionally and structurally defective, and this impairment could eventually lead to loss of podocytes and proteinuria. Thus, the glomerular-mitochondria axis can be targeted in novel treatment strategies for hypertensive glomerulosclerosis.

Pyridine nucleotides regulate the superoxide anion flash upon permeabilization of mitochondrial membranes: An MCLA-based study.

The permeabilization of mitochondrial membranes via permeability transition pore opening or by the pore-forming peptide alamethicin causes a flash of superoxide anion (SA) and hydrogen peroxide production and the inhibition of matrix aconitase. It was shown using the SA probe 3,7-dihydro-2-methyl-6-(4-methoxyphenyl)imidazol[1,2-a]pyrazine-3-one (MCLA) that the substrates of NAD-dependent dehydrogenases, inhibitors of the respiratory chain, and NAD(P)H at millimolar concentrations suppressed or delayed SA flashes. In the presence of added NADH and NADPH, SA flashes were observed only after considerable oxidation of pyridine nucleotides. The production of SA was maximal at NADPH and NADH redox potentials from -315 to -295 mV and from -325 to -270 mV, respectively, depending on NAD(P)H concentration. SA generation supported by NADPH was severalfold greater than that supported by NADH. In intact mitochondria, NADPH- and NADH-dependent SA generation was negligible. Respiratory substrates at physiological or lower concentrations were incapable of suppressing the NADPH-supported SA flash. These data indicate that, in conditions close to pathophysiological, matrix NADPH oxidoreductase(s), presumably, an adrenodoxin reductase in complex with adrenodoxin, can essentially contribute to SA flashes associated with transient or irreversible permeability transition pore opening or membrane permeabilization by another mechanism.

Predictive Value of Dynamic Cerebral Autoregulation Assessment in Surgical Management of Patients with High-Grade Carotid Artery Stenosis.

Dynamic cerebral autoregulation (DCA) capacity along with the degree of internal carotid artery (ICA) stenosis and characteristics of the plaque can also play an important role in selection of appropriate treatment strategy. This study aims to classify the patients with severe ICA stenosis according to preoperative state of DCA and to assess its dynamics after surgery. Thirty-five patients with severe ICA stenosis having different clinical type of disease underwent reconstructive surgery. DCA was assessed with transfer function analysis (TFA) by calculating phase shift (PS) between Mayer waves of blood flow velocity (BFV) and blood pressure (BP) before and after operation. In 18 cases, regardless of clinical type, preoperative PS on ipsilateral side was within the normal range and did not change considerably after surgery. In other 17 cases preoperative PS was reliably lower both in patients with symptomatic and asymptomatic stenosis. Surgical reconstruction led to restoration of impaired DCA evidenced by significant increase of PS in postoperative period. Our data suggest that regardless clinical type of disease various state of DCA may be present in patients with severe ICA stenosis. This finding can contribute to establishing the optimal treatment strategy, and first of all for asymptomatic patients. Patients with compromised DCA should be considered as ones with higher risk of stroke and first candidates for reconstructive surgery.

Glutamate contributes to alcohol hepatotoxicity by enhancing oxidative stress in mitochondria.

Chronic alcohol intoxication is associated with increased oxidative stress. However, the mechanisms by which ethanol triggers an increase in the production of reactive oxygen species (ROS) and the role of mitochondria in the development of oxidative stress has been insufficiently studied. The biochemical and proteomic data obtained in the present work suggest that one of the main causes of an increase in ROS generation is enhanced oxidation of glutamate in response to long-term alcohol exposure. In the course of glutamate oxidation, liver mitochondria from alcoholic rats generated more superoxide anion and H2O2 than in the presence of other substrates and more than control organelles. In mitochondria from alcoholic rats, rates of H2O2 production and NAD reduction in the presence of glutamate were almost twice higher than in the control. The proteomic study revealed a higher content of glutamate dehydrogenase in liver mitochondria of rats subjected to chronic alcohol exposure. Simultaneously, the content of mitochondrial catalase decreased compared to control. Each of these factors stimulates the production of ROS in addition to ROS generated by the respiratory chain complex I. The results are consistent with the conclusion that glutamate contributes to alcohol hepatotoxicity by enhancing oxidative stress in mitochondria.