ABSTRACT
Introduction: 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. Methods: Cortex, diaphragm, and quadriceps tissues from male dystrophic mdx and control mice were used. Results: 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. Conclusion: This study showed increased activity of Krebs cycle enzymes in cortex, quadriceps, and diaphragm in mdx mice. Muscle Nerve 53: 91–95, 2016
Sepsis is characterized by biochemical alterations in the central nervous system at early times and cognitive impairment at late times after induction in sepsis animal model. In order to understand ...at least in part the mechanism of disease, we have evaluated the effects of sepsis on cytokine levels in the cerebrospinal fluid (CSF); oxidative parameters; the activity of the electron transport chain enzymes; and creatine kinase (CK) activity in the brain of sepsis survivor rats 10 days after cecal ligation and perforation (CLP). Male Wistar rats underwent CLP with “basic support” or sham-operated. Ten days after surgery, the animals were killed and prefrontal cortex, cortex, hippocampus, striatum, cerebellum, and CSF were obtained. It was found a decrease in the levels of TNF-α (
P
= 0.001), IL-1β (
P
= 0.008), IL-6 (
P
= 0.038), and IL-10 (
P
= 0.022) in the CSF; an increase in the TBARS only hippocampus (0.027); an up-regulation in the activity of complex II (
P
= 0.024), III (
P
= 0.018), and IV (
P
= 0.047) only in the prefrontal cortex; a decrease in the CK activity in the cerebellum (
P
= 0.001) and striatum (
P
= 0.0001), and an increase in the hippocampus (
P
= 0.0001) and cortex (
P
= 0.0001). Oxidative stress and mitochondrial alterations observed during early times in sepsis, persisted up to 10 days after surgery. The cytokines levels during the early times were found at high levels, decreasing to low levels after 10 days. In conclusion, these findings may contribute for a better comprehension of the cognitive damage in sepsis survivor rats.
The understanding of the pathophysiology of bipolar disorder (BD) remains modest, despite recent advances in neurobiological research. The mitochondrial dysfunction hypothesis of bipolar disorder has ...been corroborated by several studies involving postmortem brain analysis, neuroimaging, and specific biomarkers in both rodent models and humans. Evidence suggests that BD might be related to abnormal mitochondrial morphology and dynamics, neuroimmune dysfunction, and atypical mitochondrial metabolism and oxidative stress pathways. Mitochondrial dysfunction in mood disorders is also associated with abnormal Ca2+ levels, glutamate excitotoxicity, an imbalance between pro- and antiapoptotic proteins towards apoptosis, abnormal gene expression of electron transport chain complexes, and decreased ATP synthesis. This paper aims to review and discuss the implications of mitochondrial dysfunction in BD etiology and to explore mitochondria as a potential target for novel therapeutic agents.
Oxidative stress has drawn a lot of attention in the past few decades, since it has been reported to participate in the mechanism of many diseases. Therefore, it seemed to be a good rationale to aim ...oxidative stress on therapeutic research. Sepsis is a complex systemic syndrome characterized by an imbalance between pro- and anti-inflammatory responses to a pathogen; its pathophysiology is a dynamic process which involves components of the immune system, the coagulation pathway, parenchymal cells, and the endocrine and metabolic pathways. It is well characterized that oxidative stress plays a crucial role in sepsis development, but the relation between central nervous system dysfunction and oxidative stress during sepsis is not well understood. Thus, we here summarize the current knowledge on the role of free radicals in the development of brain dysfunction in sepsis focusing on oxidative damage and the redox control of brain inflammatory pathways.
Background The derangement in oxygen utilization occurring during sepsis is likely to be linked to impaired mitochondrial functioning. Skeletal muscle comprises 50%–60% of body cell mass and ...represents the largest organ potentially affected by systemic inflammation. Thus, we investigated whether sepsis induced by cecal ligation and puncture (CLP) modifies mitochondrial activity in respiratory and nonrespiratory skeletal muscle. Materials and Methods Wistar rats were subjected to CLP and at different times, diaphragm and quadriceps were removed for the determination of electron transfer chain activities and mitochondrial oxidative stress. In addition, we determined diaphragm contractile strength. Results In the quadriceps, 12 h after CLP we demonstrated a significant diminution on complex II-III activity. At late times (48 h after CLP), we demonstrated a decrease in the activity of all electron transfer chain complexes, which seemed to be secondary to early oxidative stress and correlates with diaphragm contractile strength. Differently from diaphragm, electron transfer chain was not decreased after sepsis and even oxidative stress was not increased at all times tested. Conclusion Our results suggest that quadriceps mitochondria are more resistant to sepsis-induced dysfunction.
Mitochondrial oxidative phosphorylation is the major ATP-producing pathway, which supplies more than 95% of the total energy requirement in the cells. Damage to the mitochondrial electron transport ...chain has been suggested to be an important factor in the pathogenesis of a range of psychiatric disorders. Tissues with high energy demands, such as the brain, contain a large number of mitochondria, being therefore more susceptible to reduction of the aerobic metabolism. Mitochondrial dysfunction results from alterations in biochemical cascade and the damage to the mitochondrial electron transport chain has been suggested to be an important factor in the pathogenesis of a range of neuropsychiatric disorders, such as bipolar disorder, depression and schizophrenia. Bipolar disorder is a prevalent psychiatric disorder characterized by alternating episodes of mania and depression. Recent studies have demonstrated that important enzymes involved in brain energy are altered in bipolar disorder patients and after amphetamine administration, an animal model of mania. Depressive disorders, including major depression, are serious and disabling. However, the exact pathophysiology of depression is not clearly understood. Several works have demonstrated that metabolism is impaired in some animal models of depression, induced by chronic stress, especially the activities of the complexes of mitochondrial respiratory chain. Schizophrenia is a devastating mental disorder characterized by disturbed thoughts and perception, alongside cognitive and emotional decline associated with a severe reduction in occupational and social functioning, and in coping abilities. Alterations of mitochondrial oxidative phosphorylation in schizophrenia have been reported in several brain regions and also in platelets. Abnormal mitochondrial morphology, size and density have all been reported in the brains of schizophrenic individuals. Considering that several studies link energy impairment to neuronal death, neurodegeneration and disease, this review article discusses energy impairment as a mechanism underlying the pathophysiology of some psychiatric disorders, like bipolar disorder, depression and schizophrenia.
Cognitive impairment in the septic brain Comim, Clarissa M; Constantino, Leandra C; Barichello, Tatiana ...
Current neurovascular research
6, Številka:
3
Journal Article
Sepsis is a major disease entity with important clinical implications. It is associated with a high mortality rate in humans. Recently, several studies have demonstrated that Intensive Care Unit ...survivors present long-term cognitive impairment, including alterations in memory, attention, concentration and/or global loss of cognitive function. The pathogenesis of septic encephalopathy and cognitive impairment are still poorly known and further understanding of these processes is necessary for the development of effective preventive and therapeutic interventions. Here we discuss the clinical presentation and underlying pathophysiology of the encephalopathy and neurobiology of the cognitive impairment associated with sepsis.
The present study investigates the effects of incremental exercise test on muscular oxidative metabolism. Thirty-six 2-month-old male Wistar rats were distributed in seven groups that performed ...exercise at different levels: first level (control), second level (0.6 km/h), third level (0.6 and 0.8 km/h), fourth level (0.6, 0.8 and 1.0 km/h), fifth level (0.6, 0.8, 1.0 and 1.2 km/h), sixth level (0.6, 0.8, 1.0, 1.2 and 1.4 km/h), and seventh level (0.6, 0.8, 1.0, 1.2, 1.4 and 1.6 km/h). At the end of the exercise challenge, level of blood lactate (BL), glycogen content (MG), creatine kinase (CK), complexes (CI, CII, CIII, CIV), oxidative damage, succinate dehydrogenase (SDH), cytochrome
c
oxidase as well as antioxidant enzymes (SOD and CAT) expression were measured. The speed of 1.0 km/h increased BL level, while 1.2 km/h decreased MG and increased serum CK. Increased SDH expression was observed after intensity levels 6 and 7, and cytochrome
c
oxidase expression increased after levels 5, 6 and 7, in comparison with lower intensity levels, ETC enzyme activities increased when exercise was applied at intensities of 0.8 km/h (CI), 1.0 km/h (CII and CIII), and 1.2 km/h (CIV). The increase in SOD expression did not occur as observed for superoxide production, except for rats that underwent exercise at level 7, but CAT expression increased significantly in all levels, starting from level 3. Our results show interesting alterations in the muscular metabolism parameters, and suggest a differential response of muscle oxidative metabolism when intense exercise is applied at different speeds.
Several studies have appointed for a role of glutamatergic system and/or mitochondrial function in major depression. In the present study, we evaluated the creatine kinase and mitochondrial ...respiratory chain activities after acute and chronic treatments with memantine (
N
-methyl-
d
-aspartate receptor antagonist) and imipramine (tricyclic antidepressant) in rats. To this aim, rats were acutely or chronically treated for 14 days once a day with saline, memantine (5, 10 and 20 mg/kg) and imipramine (10, 20 and 30 mg/kg). After acute or chronic treatments, we evaluated mitochondrial respiratory chain complexes (I, II, II–III and IV) and creatine kinase activities in prefrontal cortex, hippocampus and striatum. Our results showed that both acute and chronic treatments with memantine or imipramine altered respiratory chain complexes and creatine kinase activities in rat brain; however, these alterations were different with relation to protocols (acute or chronic), complex, dose and brain area. Finally, these findings further support the hypothesis that the effects of imipramine and memantine could be involve mitochondrial function modulation.
Maple syrup urine disease (MSUD) is a neurometabolic disorder caused by deficiency of the activity of the mitochondrial enzyme complex branched-chain α-keto acid dehydrogenase leading to accumulation ...of the branched-chain amino acids (BCAA) and their corresponding branched-chain α-keto acids. In this study, we examined the effects of acute and chronic administration of BCAA on protein levels and mRNA expression of nerve growth factor (NGF) considering that patients with MSUD present neurological dysfunction and cognitive impairment. Considering previous observations, it is suggested that oxidative stress may be involved in the pathophysiology of the neurological dysfunction of MSUD. We also investigated the influence of antioxidant treatment (
N
-acetylcysteine and deferoxamine) in order to verify the influence of oxidative stress in the modulation of NGF levels. Our results demonstrated decreased protein levels of NGF in the hippocampus after acute and chronic administration of BCAA. In addition, we showed a significant decrease in the expression of
ngf
in the hippocampus only following acute administration in 10-day-old rats. Interestingly, antioxidant treatment was able to prevent the decrease in NGF levels by increasing
ngf
expression. In conclusion, the results suggest that BCAA is involved in the regulation of NGF in the developing rat. Thus, it is possible that alteration of neurotrophin levels during brain maturation could be of pivotal importance in the impairment of cognition provoked by BCAA. Moreover, the decrease in NGF levels was prevented by antioxidant treatment, reinforcing that the hypothesis of oxidative stress can be an important pathophysiological mechanism underlying the brain damage observed in MSUD.
