Activities Of Krebs Cycle Enzymes Research Articles

Renoprotective effect of hyperin against CdCl2 prompted renal damage by activation of Nrf-2/Keap-1 ARE pathway in male mice

Objectives This study explored the mitigating properties of hyperin (HYP) on renotoxicity induced by cadmium chloride (CdCl2). Methods Four groups of seven male albino mice each were used in this experiment. Group 1 served as the control, receiving no treatment. Group 2 received daily oral gavage of CdCl2 at 0.3 mg/kg body weight for 28 d. Group 3 received both CdCl2 (0.3 mg/kg) and HYP (100 mg/kg) daily using the same administration method. Finally, Group 4 received only HYP (100 mg/kg) daily. Results Cd exposure significantly increased kidney dysfunction markers (blood urea nitrogen and creatinine) and oxidative stress (reactive oxygen species [ROS] and malondialdehyde [MDA]). Conversely, it decreased antioxidant enzyme activities (glutathione peroxidase (GPx] and catalase [CAT]) and glutathione (GSH) levels. Nuclear factor erythroid 2-related factor 2 (Nrf-2) and antioxidant gene expression decreased, while Kelch-like ECH-associated protein 1 expression increased. Additionally, Cd exposure increased inflammatory mediators (nuclear factor kappa B, tumor necrosis factor alpha [TNF-α], interleukin-1β [IL-1β], and cyclooxygenase-2) and apoptotic markers (Bax and caspase-3), alongside decreased Bcl-2 expression and renal tissue abnormalities. Mitochondrial dysfunction manifested with diminished activities of Krebs cycle and respiratory chain enzymes, and reduced mitochondrial membrane potential. Co-treatment with HYP significantly attenuated these detrimental effects through its anti-apoptotic, antioxidant, and anti-inflammatory properties. Conclusion HYP co-treatment significantly attenuated CdCl2-induced renal damage in mice, suggesting its potential as a protective agent against Cd-induced kidney toxicity.

Mitochondrial cerebral dysfunction in rats with scopolamine-induced neurodegeneration under enalapril effect

Objective. Neurodestructive diseases are characterized by complex pathobiochemical cascades in the neuron, which cause disturbances in energy metabolism and the formation of mitochondrial dysfunction. The renin-angiotensin system plays an important role in the physiological functioning of mitochondria, the excessive activity of which increases the risk of neurodegenerative diseases of the brain. Although angiotensin-converting enzyme inhibitors are now considered as means of prevention and treatment of ischemic lesions of the central nervous system, their corrective properties in the development of central neurodegeneration continue to be refined. The objective of our study was investigation of enalapril effect, as an angiotensin-converting enzyme inhibitor, in case of mitochondrial dysfunction of the cerebral cortex and hippocampus of rats under conditions of scopolamine-induced neurodegeneration reproducing development of Alzheimer’s disease in the experiment.Material and methods. Scopolamine hydrochloride (Sigma, USA) was injected in rats through the peritoneum at a dose of 1 mg/kg for 27 days to simulate Alzheimer’s disease. Starting from the 28th day of the experiment, enalapril was introduced through the peritoneum at a dose of 1 mg/kg, once a day for 14 days.
 Results. Under conditions of scopolamine-induced Alzheimer’s disease in the mitochondrial fraction of the cerebral cortex and hippocampus of rats free radical oxidation of lipids and proteins ncreases, and activity of Krebs cycle enzymes decreases – α-ketoglutarate dehydrogenase and succinate dehydrogenase; light dispersion decreases and a relative rate of mitochondrial swelling increases. After enalapril administration for 14 days to rats with scopolamine-induced Alzheimer’s disease the content of products reacting with 2-thiobarbituric acid and protein oxidation modification decreases in the mitochondrial fraction of the cerebral cortex and hippocampus; in both examined structures, the activity of catalase, αketoglutarate dehydrogenase, succinate dehydrogenase increases, and superoxide dismutase – only in the cerebral cortex; a gradual decrease of light dispersion and relative rate of mitochondrial swelling occurs.Conclusion. Improvement of the antioxidant system state and energy supply of mitochondria, decreased intensity of mitochondrial swelling in the cerebral cortex and hippocampus of rats with scopolamine-induced Alzheimer’s disease are indicative of the protective properties of enalapril.

Protective Effect of D-Panthenol in Rhabdomyolysis-Induced Acute Kidney Injury.

We investigated the nephroprotective effect of D-panthenol in rhabdomyolysis-induced acute kidney injury (AKI). Adult male Wistar rats were injected with 50% glycerol solution to induce rhabdomyolysis. Animals with rhabdomyolysis were injected with D-panthenol (200 mg/kg) for 7 days. On day 8, we examined AKI markers, renal histology, antioxidant capacity, and protein glutathionylation in kidneys to uncover mechanisms of D-panthenol effects. Rhabdomyolysis kidneys were shown to have pathomorphological alterations (mononuclear infiltration, dilatation of tubules, and hyaline casts in Henle’s loops and collecting ducts). Activities of skeletal muscle damage markers (creatine kinase and lactate dehydrogenase) increased, myoglobinuria was observed, and creatinine, BUN, and pantetheinase activity in serum and urine rose. Signs of oxidative stress in the kidney tissue of rhabdomyolysis rats, increased levels of lipid peroxidation products, and activities of antioxidant enzymes (SOD, catalase, and glutathione peroxidase) were all alleviated by administration of D-panthenol. Its application improved kidney morphology and decreased AKI markers. Mechanisms of D-panthenol’s beneficial effects were associated with an increase in total coenzyme A levels, activity of Krebs cycle enzymes, and attenuation of protein glutathionylation. D-Panthenol protects kidneys from rhabdomyolysis-induced AKI through antioxidant effects, normalization of mitochondrial metabolism, and modulation of glutathione-dependent signaling.

Insulin-Induced Recurrent Hypoglycemia Up-Regulates Glucose Metabolism in the Brain Cortex of Chemically Induced Diabetic Rats.

Diabetes is a chronic metabolic disease that seriously compromises human well-being. Various studies highlight the importance of maintaining a sufficient glucose supply to the brain and subsequently safeguarding cerebral glucose metabolism. The goal of the present work is to clarify and disclose the metabolic alterations induced by recurrent hypoglycemia in the context of long-term hyperglycemia to further comprehend the effects beyond brain harm. To this end, chemically induced diabetic rats underwent a protocol of repeatedly insulin-induced hypoglycemic episodes. The activity of key enzymes of glycolysis, the pentose phosphate pathway and the Krebs cycle was measured by spectrophotometry in extracts or isolated mitochondria from brain cortical tissue. Western blot analysis was used to determine the protein content of glucose and monocarboxylate transporters, players in the insulin signaling pathway and mitochondrial biogenesis and dynamics. We observed that recurrent hypoglycemia up-regulates the activity of mitochondrial hexokinase and Krebs cycle enzymes (namely, pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase and succinate dehydrogenase) and the protein levels of mitochondrial transcription factor A (TFAM). Both insults increased the nuclear factor erythroid 2–related factor 2 (NRF2) protein content and induced divergent effects in mitochondrial dynamics. Insulin-signaling downstream pathways were found to be down-regulated, and glycogen synthase kinase 3 beta (GSK3β) was found to be activated through both decreased phosphorylation at Ser9 and increased phosphorylation at Y216. Interestingly, no changes in the levels of cAMP response element-binding protein (CREB), which plays a key role in neuronal plasticity and memory, were caused by hypoglycemia and/or hyperglycemia. These findings provide experimental evidence that recurrent hypoglycemia, in the context of chronic hyperglycemia, has the capacity to evoke coordinated adaptive responses in the brain cortex that will ultimately contribute to sustaining brain cell health.

Changes in energetic metabolism and lysosomal destruction in the skeletal muscle and cardiac tissues of pigeons (Columba livia f. urbana) from urban areas of the northern Pomeranian region (Poland)

The aim of the present study was to evaluate the biochemical responses of the skeletal muscle and cardiac tissues of the urban pigeon as a bioindicator organism tested in diverse environments (Szpęgawa as a rural environment and Słupsk as an urban environment, Pomeranian Voivodeship, northern Poland), resulting in changes in the level of lipid peroxidation at the initial and final stages of this process and the activities of Krebs cycle enzymes (succinate dehydrogenase, pyruvate dehydrogenase, isocitrate dehydrogenase, and alfa-ketoglutarate dehydrogenase). Szpęgawa village was chosen due to the intensive use of the European motorway A1 with significant traffic and pollution levels. The concentration of Pb was higher in the soil and feathers of pigeons nesting in the polluted areas (Szpęgawa). Our studies have shown that the presence of lead in soil and feathers of the pigeons resulted in the activation of lipid peroxidation, destabilization and increased activity of lysosomal membranes, and activation of mitochondrial enzymes of the Krebs cycle with energy deficiency (reduction of ATP levels) in cardiac and skeletal muscle tissues simultaneously.

Role of mitochondria in the differential action of sodium deoxycholate and ursodeoxycholic acid on rat duodenum.

Sodium deoxycholate (NaDOC) inhibits the intestinal Ca2+ absorption and ursodeoxycholic acid (UDCA) stimulates it. The aim of this study was to determine whether NaDOC and UDCA produce differential effects on the redox state of duodenal mitochondria altering the Krebs cycle and the electron transport chain (ETC) functioning, which could lead to perturbations in the mitochondrial dynamics and biogenesis. Rat intestinal mitochondria were isolated from untreated and treated animals with either NaDOC, UDCA, or both. Krebs cycle enzymes, ETC components, ATP synthase, and mitochondrial dynamics and biogenesis markers were determined. NaDOC decreased isocitrate dehydrogenase (ICDH) and malate dehydrogenase activities affecting the ETC and ATP synthesis. NaDOC also induced oxidative stress and increased the superoxide dismutase activity and impaired the mitochondrial biogenesis and functionality. UDCA increased the activities of ICDH and complex II of ETC. The combination of both bile acids conserved the functional activities of Krebs cycle enzymes, ETC components, oxidative phosphorylation, and mitochondrial biogenesis. In conclusion, the inhibitory effect of NaDOC on intestinal Ca2+ absorption is mediated by mitochondrial dysfunction, which is avoided by UDCA. The stimulatory effect of UDCA alone is associated with amelioration of mitochondrial functioning. This knowledge could improve treatment of diseases that affect the intestinal Ca2+ absorption.

Beta-estradiol protects against copper-ascorbate induced oxidative damage in goat liver mitochondria in vitro by binding with ascorbic acid

Aimsβ-Estradiol (β-E), one of the chemical forms of female gonad hormone exhibited antioxidant efficacy in biochemical system, in vitro. The aim of the study was to investigate whether any other mechanism of protection by β-E to hepatic mitochondria in presence of stressor agent i.e.,a combination of Cu2+ and ascorbic acid is involved. Main methodsFreshly prepared goat liver mitochondria was incubated with stressors and 1 μM β-E and post incubated with the same concentration at 37 °C at pH 7.4. Mitochondrial viability, biomarkers of oxidative stress, activities of Krebs cycle enzymes, mitochondrial membrane potential, Ca2+ permeability were measured. Mitochondrial morphology and binding pattern of β-E with stressors were also studied. Key findingsUpon incubation of mitochondria with Cu, ascorbic acid and their combination there is a significant decline in activities of four of Krebs cycle enzymes in an uncompetitive manner with a concomitant increase in Ca2+ permeability and membrane potential of inner mitochondrial membrane, which is withdrawn during co-incubation with β-E, but was not reversed during post incubation with the β-E. The final studies on mitochondrial membrane morphology using scanning electron microscope also exhibited damage. Isothermal titration calorimetry data also showed the negative heat change in the mixture of β-E with ascorbic acid and also its combination with Cu2+. SignificanceOur results for the first time demonstrated that β-E protects againstCu2+-ascorbate induced oxidative stress by binding with ascorbic acid. The new mechanism of binding of β-E with stress agents may have a future therapeutic relevance.

Oleic acid protects against cadmium induced cardiac and hepatic tissue injury in male Wistar rats: A mechanistic study

AimsThe aim of the present study was to evaluate the possible antioxidant role of oleic acid (OA) against Cd-induced injuries in the heart and liver tissues of male Wistar rats. Main methodsRats were treated with either vehicle (control), or OA (10 mg/kg b.w., fed orally), or Cd (0.44 mg/kg b.w., s.c.), or both (OA + Cd) for 15 days. Following completion of the treatment period, biomarkers of organ damage and oxidative stress including ROS, activities of antioxidant enzymes and their level, activities of Krebs cycle enzymes and respiratory chain enzymes were measured. Levels of interleukins (IL-1β, IL-6, IL-10), tumor necrosis factor (TNF-α) and nuclear factor kappa B (NFκB) were estimated to evaluate the state of inflammation. In addition, changes in mitochondrial membrane potential and status of cytochrome c (Cyt c) were also studied. Key findingsPre-treatment of rats with OA significantly protected against Cd-induced detrimental changes possibly by decreasing endogenous ROS through regulation of antioxidant defense system, inflammatory responses and activities of metabolic enzymes. Moreover, OA was also found to restore mitochondrial membrane potential possibly by regulating Cyt c leakage thereby increasing mitochondrial viability. SignificanceOur results for the first time demonstrated systematically that OA provided protection against Cd-induced oxidative stress mediated injuries in rat heart and liver tissues through its antioxidant mechanism. The results raise the possibility of using OA singly or in combination with other antioxidants or diet in the treatment of situations arising due to oxidative stress and may have future therapeutic relevance.

Brain glucose and ketone utilization in brain aging and neurodegenerative diseases.

To meet its high energy demands, the brain mostly utilizes glucose. However, the brain has evolved to exploit additional fuels, such as ketones, especially during prolonged fasting. With aging and neurodegenerative diseases (NDDs), the brain becomes inefficient at utilizing glucose due to changes in glia and neurons that involve glucose transport, glycolytic and Krebs cycle enzyme activities, and insulin signaling. Positron emission tomography and magnetic resonance spectroscopy studies have identified glucose metabolism abnormalities in aging, Alzheimer's disease (AD) and other NDDs in vivo. Despite glucose hypometabolism, brain cells can utilize ketones efficiently, thereby providing a rationale for the development of therapeutic ketogenic interventions in AD and other NDDs. This review compares available ketogenic interventions and discusses the potential of the potent oral Ketone Ester for future therapeutic use in AD and other NDDs characterized by inefficient glucose utilization.

Synthesis and Biological Assessment of Pyrrolobenzoxazine Scaffold as a Potent Antioxidant.

Reduction of mitochondrial oxidative stress-mediated diseases is an important pharmaceutical objective in recent biomedical research. In this context, a series of novel pyrrolobenzoxazines (PyBs) framework with enormous diversity (compounds 5a-w) was synthesized by employing a low-temperature greener pathway, and antioxidant property of the synthesized compounds was successfully demonstrated on preclinical model goat heart mitochondria, in vitro. Copper-ascorbate (Cu-As) was utilized as an oxidative stress generator. Out of screened PyBs, the compound possessing -OH and -OMe groups on benzene nucleus along with pyrrolobenzoxazine core moiety (compound 5w) displayed magnificent antioxidant property with a minimum effective dose of 66 μM during the biochemical assessment. The ameliorative effect of synthesized pyrrolobenzoxazine moiety on levels of biomarkers of oxidative stress, antioxidant enzyme, activities of Krebs cycle and respiratory chain enzymes, mitochondrial morphology, and Ca2+ permeability of mitochondrial membrane was investigated in the presence of Cu-As. Furthermore, the binding mode of Cu-As by compound 5w was explored successfully using isothermal titration calorimetry (ITC) analysis.

Effect of physiological active compounds on status of prooxidative-antioxidative balance and activity of Krebs cycle enzymes in heart and liver tissues under doxorubicin-induced cardiomyopathy

A study was conducted to determinate the effects of Tiotriasolin, Qudesan and the precursors of ubiquinone synthesis (EPM-Mg: alpha-tocopherol acetate), 4-hydroxybenzoic acid, methionine, Mg2+ ions) on the free radical processes and activity of some Krebs cycle dehydrogenases in rat heart and liver tissues under conditions of doxorubicin-induced cardiomyopathy. Administration of doxorubicin intensified the processes of lipid and protein oxidation and suppressed antioxidant enzymes activity in liver and heart tissues. Administration of metabolic correctional drugs caused a decrease the negative effect of doxorubicin on antioxidant system of heart and liver tissues due to increased activity of catalase and superoxide dismutase and inhibition of free radical processes. Doxorubicin administration caused an increase activity of both dehydrogenases in cardiomyocytes, which can be explained by triggering compensatory mechanisms in organ’s cells. The intake of metabolic drugs decreases the negative effect of anthracycline and approximates the dehydrogenase activity, which is close to the control values. In contrast to heart tissues, doxorubicin administration did not cause significant changes in the activity of energy enzymes in liver tissues, which may be due to the presence in the cells of liver a relatively powerful antioxidant defense system (capable in this experimental conditions effectively counteract doxorubicin-induced free radical processes). Administration of Qudesan and EPM-Mg caused a significant increase of alpha-ketoglutarate dehydrogenase and succinate dehydrogenase activities, which indicates the positive effect of these substances on work of the cell energy system.

Levels of Thyroid Hormones and Indices of Energy Metabolism in the Cerebral Cortex of Rats with Experimental Alzheimer’s Disease

The study was carried out on 30 mature WAG rats, 15 intact control animals and 15 rats with modeled Alzheimer’s disease (AD) induced by course injections of scopolamine (27 days, 1 mg/kg, i.p. daily). The contents of ATP, glucose, pyruvate, and lactate were measured spectrophotometrically in homogenates of the brain cortex of the animals. The levels of TSH, T3, and T4 in blood serum and those of T3 and T4 in cortex homogenates were estimated using ELISA. The activities of pyruvate dehydrogenase, creatine phosphokinase, and key enzymes of the tricarboxylic acid cycle (TCA) were measured in the mitochondria using a spectrophotometric technique. It was found that the content of T3 in the brain cortex of rats was much lower than in the controls against the background of higher T4 concentrations, which was indicative of the development of local hypothyroidism in the brain. The increased activity of pyruvate dehydrogenase against the background of low activities of TCA cycle enzymes in brain homogenates was observed. The decreased creatine kinase activity and low ATP contents were also found. Local hypothyroidism in the brain cortex is believed to be one of the significant factors inducing the development of strong energy deficiency and reducing the activity of Krebs cycle enzymes. Consequently, this contributes to the death of neurons in experimental AD in rats.

Omega-3 Fatty Acids Attenuate Brain Alterations in High-Fat Diet-Induced Obesity Model.

This study evaluated the effects of omega-3 on inflammation, oxidative stress, and energy metabolism parameters in the brain of mice subjected to high-fat diet-induced obesity model. Body weight and visceral fat weight were evaluated as well. Male Swiss mice were divided into control (purified low-fat diet) and obese (purified high-fat diet). After 6weeks, the groups were divided into control + saline, control + omega-3, obese + saline, and obese + OMEGA-3. Fish oil (400mg/kg/day) or saline solution was administrated orally, during 4weeks. When the experiment completed 10weeks, the animals were euthanized and the brain and visceral fat were removed. The brain structures (hypothalamus, hippocampus, prefrontal cortex, and striatum) were isolated. Treatment with omega-3 had no effect on body weight, but reduced the visceral fat. Obese animals showed increased inflammation, increased oxidative damage, decreased antioxidant enzymes activity and levels, changes in the Krebs cycle enzyme activities, and inhibition of mitochondrial respiratory chain complexes in the brain structures. Omega-3 treatment partially reversed the changes in the inflammatory and in the oxidative damage parameters and attenuated the alterations in the antioxidant defense and in the energy metabolism (Krebs cycle and mitochondrial respiratory chain). Omega-3 had a beneficial effect on the brain of obese animals, as it partially reversed the changes caused by the consumption of a high-fat diet and consequent obesity. Our results support studies that indicate omega-3 may contribute to obesity treatment.

Стан прооксидантно-антиоксидантної рівноваги та активність ензимів циклу Кребса у тканинах печінки, серця і нирок за дії різних кумулятивних доз доксорубіцину

Стан прооксидантно-антиоксидантної рівноваги та активність ензимів циклу Кребса у тканинах печінки, серця і нирок за дії різних кумулятивних доз доксорубіцину

Mitochondrial Bioenergetics and Dysfunction in Failing Heart.

Energy insufficiency has been recognized as a key feature of systolic heart failure. Although mitochondria have long been known to sustain myocardial work energy supply, the capacity to therapeutically target mitochondrial bioenergetics dysfunction is hampered by a complex interplay of multiple perturbations that progressively compound causing myocardial failure and collapse. Compared to non-failing human donor hearts, activity rates of complexes I and IV, nicotinamide nucleotide transhydrogenase (NADPH-transhydrogenase, Nnt) and the Krebs cycle enzymes isocitrate dehydrogenase, malate dehydrogenase and aconitase are markedly decreased in end-stage heart failure. Diminished REDOX capacity with lower total glutathione and coenzyme Q10 levels are also a feature of chronic left ventricular failure. Decreased enzyme activities in part relate to abundant and highly specific oxidative, nitrosylative, and hyperacetylation modifications. In this brief review we highlight that energy deficiency in end-stage failing human left ventricle predominantly involves concomitantly impaired activities of key electron transport chain and Krebs cycle enzymes rather than altered expression of respective genes or proteins. Augmented oxidative modification of these enzyme subunit structures, and the formation of highly reactive secondary metabolites, implicates dysfunction due to diminished capacity for management of mitochondrial reactive oxygen species, which contribute further to progressive decreases in bioenergetic capacity and contractile function in human heart failure.

Posttranslational modifications and dysfunction of mitochondrial enzymes in human heart failure

Deficiency of energy supply is a major complication contributing to the syndrome of heart failure (HF). Because the concurrent activity profile of mitochondrial bioenergetic enzymes has not been studied collectively in human HF, our aim was to examine the mitochondrial enzyme defects in left ventricular myocardium obtained from explanted end-stage failing hearts. Compared with nonfailing donor hearts, activity rates of complexes I and IV and the Krebs cycle enzymes isocitrate dehydrogenase, malate dehydrogenase, and aconitase were lower in HF, as determined spectrophotometrically. However, activity rates of complexes II and III and citrate synthase did not differ significantly between the two groups. Protein expression, determined by Western blotting, did not differ between the groups, implying posttranslational perturbation. In the face of diminished total glutathione and coenzyme Q10 levels, oxidative modification was explored as an underlying cause of enzyme dysfunction. Of the three oxidative modifications measured, protein carbonylation was increased significantly by 31% in HF (P < 0.01; n = 18), whereas levels of 4-hydroxynonenal and protein nitration, although elevated, did not differ. Isolation of complexes I and IV and F1FoATP synthase by immunocapture revealed that proteins containing iron-sulphur or heme redox centers were targets of oxidative modification. Energy deficiency in end-stage failing human left ventricle involves impaired activity of key electron transport chain and Krebs cycle enzymes without altered expression of protein levels. Augmented oxidative modification of crucial enzyme subunit structures implicates dysfunction due to diminished capacity for management of mitochondrial reactive oxygen species, thus contributing further to reduced bioenergetics in human HF.

Muscle biopsies from human muscle diseases with myopathic pathology reveal common alterations in mitochondrial function.

Muscle diseases are clinically and genetically heterogeneous and manifest as dystrophic, inflammatory and myopathic pathologies, among others. Our previous study on the cardiotoxin mouse model of myodegeneration and inflammation linked muscle pathology with mitochondrial damage and oxidative stress. In this study, we investigated whether human muscle diseases display mitochondrial changes. Muscle biopsies from muscle disease patients, represented by dysferlinopathy (dysfy) (dystrophic pathology; n=43), polymyositis (PM) (inflammatory pathology; n=24), and distal myopathy with rimmed vacuoles (DMRV) (distal myopathy; n=31) were analyzed. Mitochondrial damage (ragged blue and COX-deficient fibers) was revealed in dysfy, PM, and DMRV cases by enzyme histochemistry (SDH and COX-SDH), electron microscopy (vacuolation and altered cristae) and biochemical assays (significantly increased ADP/ATP ratio). Proteomic analysis of muscle mitochondria from all three muscle diseases by isobaric tag for relative and absolute quantitation labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis demonstrated down-regulation of electron transport chain (ETC) complex subunits, assembly factors and Krebs cycle enzymes. Interestingly, 80 of the under-expressed proteins were common among the three pathologies. Assay of ETC and Krebs cycle enzyme activities validated the MS data. Mitochondrial proteins from muscle pathologies also displayed higher tryptophan (Trp) oxidation and the same was corroborated in the cardiotoxin model. Molecular modeling predicted Trp oxidation to alter the local structure of mitochondrial proteins. Our data highlight mitochondrial alterations in muscle pathologies, represented by morphological changes, altered mitochondrial proteome and protein oxidation, thereby establishing the role of mitochondrial damage in human muscle diseases. We investigated whether human muscle diseases display mitochondrial changes. Muscle biopsies from dysferlinopathy (Dysfy), polymyositis (PM), and distal myopathy with rimmed vacuoles (DMRV) displayed morphological and biochemical evidences of mitochondrial dysfunction. Proteomic analysis revealed down-regulation of electron transport chain (ETC) subunits, assembly factors, and tricarboxylic acid (TCA) cycle enzymes, with 80 proteins common among the three pathologies. Mitochondrial proteins from muscle pathologies also displayed higher Trp oxidation that could alter the local structure. Cover image for this issue: doi: 10.1111/jnc.13324.

Omega-3 fatty acids combined with aripiprazole and lithium modulates activity of mitochondrial enzymes and acetylcholinesterase in methylphenidate-induced animal model of mania

Many studies have shown the alterations of mitochondrial complexes in bipolar disorder (BD) patients. However, changes in the Krebs cycle enzymes have been little studied.The animal model of mania induced by psychostimulants like amphetamine and methylphenidate (MPD) has been widely used to study the manic phase of bipolar disorder. The aim of the present study is to assess the changes in the activity of Krebs cycle enzymes and acetylcholinesterase (AChE) in an animal model of mania induced by MPD. wiss albino mice were first administered intraperitonially with MPD (5mg/kg) or saline for 14 days, upon changes in the behavioral activity, animals were treated with lithium (50mg/kg), omega-3 fatty acids (1.5ml/kg) given orally and aripiprazole administered intraperitonially (1.5mg/kg) from 8th day onwards. Activity of Krebs cycle enzymes and AChE were measured in brain. Administration of MPD inhibited the activity of Krebs cycle enzymes and AChE in brain. Treatment with lithium, aripiprazole and omega-3 fatty acids significantly reversed MPD induced mitochondrial dysfunction and AChE activity. This finding suggest that lithium, aripiprazole and omega-3 fatty acids exert protective effect against MPD induced impairment of Krebs cycle enzymes in brain of mice; further supporting the hypothesis that mitochondrial dysfunction may be associated with the pathophysiology of BD.

Activity of Krebs cycle enzymes in mdx mice.

Duchenne muscular dystrophy (DMD) is a degenerative disease of skeletal, respiratory, and cardiac muscles caused by defects in the dystrophin gene. More recently, brain involvement has been verified. Mitochondrial dysfunction and oxidative stress may underlie the pathophysiology of DMD. In this study we evaluate Krebs cycle enzymes activity in the cerebral cortex, diaphragm, and quadriceps muscles of mdx mice. Cortex, diaphragm, and quadriceps tissues from male dystrophic mdx and control mice were used. We observed increased malate dehydrogenase activity in the cortex; increased malate dehydrogenase and succinate dehydrogenase activities in the diaphragm; and increased citrate synthase, isocitrate dehydrogenase, and malate dehydrogenase activities in the quadriceps of mdx mice. This study showed increased activity of Krebs cycle enzymes in cortex, quadriceps, and diaphragm in mdx mice.

Fluvoxamine alters the activity of energy metabolism enzymes in the brain

Several studies support the hypothesis that metabolism impairment is involved in the pathophysiology of depression and that some antidepressants act by modulating brain energy metabolism. Thus, we evaluated the activity of Krebs cycle enzymes, the mitochondrial respiratory chain, and creatine kinase in the brain of rats subjected to prolonged administration of fluvoxamine. Wistar rats received daily administration of fluvoxamine in saline (10, 30, and 60 mg/kg) for 14 days. Twelve hours after the last administration, rats were killed by decapitation and the prefrontal cortex, cerebral cortex, hippocampus, striatum, and cerebellum were rapidly isolated. The activities of citrate synthase, malate dehydrogenase, and complexes I, II-III, and IV were decreased after prolonged administration of fluvoxamine in rats. However, the activities of complex II, succinate dehydrogenase, and creatine kinase were increased. Alterations in activity of energy metabolism enzymes were observed in most brain areas analyzed. Thus, we suggest that the decrease in citrate synthase, malate dehydrogenase, and complexes I, II-III, and IV can be related to adverse effects of pharmacotherapy, but long-term molecular adaptations cannot be ruled out. In addition, we demonstrated that these changes varied according to brain structure or biochemical analysis and were not dose-dependent.