N-acetylcysteine suppresses oxidative stress in experimental rats with subarachnoid hemorrhage

Goat Milk Supplementation Modulates the Mitochondrial Metabolic Flexibility and Orexin-A Levels Influencing the Inflammatory Pattern in Rats

Milk and its derivatives are included in a balanced diet of humans as excellent sources of proteins, vitamins, and essential minerals that are functional nutrients. Knowledge about the nutritional benefits or harms due to milk consumption has been expanding in recent years. We previously explored, in rodent models, the metabolic effects of isoenergetic intake of milk derived from cows, donkeys, or humans, while the impact of goat's milk intake has remained unexplored. The aim of this work was to investigate, in an animal model, the effects of dietary supplementation with goat's milk on energy homeostasis and inflammatory state, focusing on the modulation of mitochondrial functions in most metabolically active organs, such as skeletal muscle and the liver. In addition, we highlighted a link between nutrient intake, substrate metabolism, and the orexinergic system. Our results indicate that goat milk improves mitochondrial oxidative capacity and reduces inflammation and oxidative stress in both organs. Notably, goat milk lowers the circulating levels of Orexin-A, a neuropeptide that plays a crucial role in regulating peripheral energy balance and central nervous system mechanisms. These data provide the first evidence that the anti-inflammatory and antioxidant effects of goat milk are mediated by the modulation of mitochondrial functions and orexinergic signaling.

Mitochondrial metabolism and neuroinflammation in the cerebral cortex and cortical synapses of rats: effect of milk intake through DNA methylation

Brain plasticity and cognitive functions are tightly influenced by foods or nutrients, which determine a metabolic modulation having a long-term effect on health, involving also epigenetic mechanisms. Breast milk or formula based on cow milk is the first food for human beings, who, throughout their lives, are then exposed to different types of milk. We previously demonstrated that rats fed with milk derived from distinct species, with different compositions and nutritional properties, display selective modulation of systemic metabolic and inflammatory profiles through changes of mitochondrial functions and redox state in liver, skeletal and cardiac muscle. Here, in a rat model, we demonstrated that isoenergetic supplementation of milk from cow (CM), donkey (DM) or human (HM) impacts mitochondrial functions and redox state in the brain cortex and cortical synapses, affecting neuroinflammation and synaptic plasticity. Interestingly, we found that the administration of different milk modulates DNA methylation in rat brain cortex and consequently affects gene expression. Our results emphasize the importance of nutrition in brain and synapse physiology, and highlight the key role played in this context by mitochondria, nutrient-sensitive organelles able to orchestrate metabolic and inflammatory responses.

An investigation of the endoplasmic reticulum stress in obesity exposure in the prenatal period

OBJECTIVES

Exposure to maternal obesity has been shown to make offspring more prone to cognitive and metabolic disorders later in life. Although the underlying mechanisms are unclear, the role of endoplasmic reticulum (ER) stress in the fetal programming process is remarkable. ER stress can be activated by many chronic diseases, including obesity and diabetes. Therefore, our study aimed to investigate the role of ER stress caused by maternal diet-induced obesity in the offspring hippocampus. We also evaluated the protective effect of N-acetylcysteine (NAC) against ER stress.

METHODS

A rat obesity model was created by providing a high-fat (60 % kcal) diet. N-acetylcysteine (NAC) was administered at a dosage of 150 mg/kg via the intragastric route. The animals were mated at the age of 12 weeks. The same diet was maintained during pregnancy and lactation. The experiment was terminated on the postnatal 28th day, and the offspring's brain tissues were examined. Immunohistochemical staining for ER stress markers was performed on sections taken from tissues after routine histological procedures.

RESULTS

The results revealed increased GRP78, PERK, and eIF2α immunoreactivities in the hippocampal dentate gyrus (DG) and cornu ammonis 1 (CA1) regions in the obese group offspring, while the expression of those markers in those regions normalized with NAC supplementation (p < 0.01). Statistical analysis of XBP1 immunoreactivity H-scores revealed no difference between the study groups (p > 0.05).

DISCUSSION

These results suggest that exposure to obesity during the prenatal period may cause increased ER stress in hippocampal neurons, which have an important role in the regulation of learning, memory and behavior, and this may contribute to decreased cognitive performance. On the other hand, NAC stands out as an effective agent that can counteract hippocampal ER stress.

Crosstalk between Adipose Tissue and Hepatic Mitochondria in the Development of the Inflammation and Liver Injury during Ageing in High-Fat Diet Fed Rats

Obesity is considered an epidemic disorder, due to an imbalance between energy consumption and metabolizable energy intake. This balance is increasingly disrupted during normal aging processes due to the progressive impairment of mechanisms that normally control energy homeostasis. Obesity is triggered by an excessive lipid depots but reflects systemic inflammation along with large adipocytes secreting proinflammatory adipokines, an increase of the free fatty acids levels in the bloodstream, and ectopic lipid accumulation. Hepatic fat accumulation is the most common cause of chronic liver disease, characterized by mitochondrial dysfunction with a consequent impaired fat metabolism and increased oxidative stress. Therefore, mitochondrial dysfunction is associated to hepatic lipid accumulation and related complications. In this study, we assessed the crosstalk between adipose tissue and liver, analyzing the time-course of changes in hepatic mitochondrial fatty acid oxidation capacity versus fatty acid storage, focusing on the contribution of adipose tissue inflammation to hepatic lipid accumulation, using a rodent model of high fat diet-induced obesity. Our results demonstrate that both high-fat diet-induced obesity and aging induce dysregulation of adipose tissue function and similar metabolic alterations mediated by mitochondrial function impairment and altered inflammatory profile. The high fat diet-induced obesity anticipates and exacerbates liver mitochondrial dysfunction that occurs with aging processes.

Elucidating the progress and impact of ferroptosis in hemorrhagic stroke

Hemorrhagic stroke is a devastating cerebrovascular disease with high morbidity and mortality, for which effective therapies are currently unavailable. Based on different bleeding sites, hemorrhagic stroke can be generally divided into intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH), whose pathogenesis share some similarity. Ferroptosis is a recently defined programmed cell deaths (PCDs), which is a critical supplement to the hypothesis on the mechanism of nervous system injury after hemorrhagic stroke. Ferroptosis is characterized by distinctive morphological changes of mitochondria and iron-dependent accumulation of lipid peroxides. Moreover, scientists have successfully demonstrated the involvement of ferroptosis in animal models of ICH and SAH, indicating that ferroptosis is a promising target for hemorrhagic stroke therapy. However, the studies on ferroptosis still faces a serious of technical and theoretical challenges. This review systematically elaborates the role of ferroptosis in the pathogenesis of hemorrhagic stroke and puts forward some opinions on the dilemma of ferroptosis research.

Butyrate Improves Neuroinflammation and Mitochondrial Impairment in Cerebral Cortex and Synaptic Fraction in an Animal Model of Diet-Induced Obesity

Neurodegenerative diseases (NDDs) are characterized by cognitive impairment and behavioural abnormalities. The incidence of NDDs in recent years has increased globally and the pathological mechanism is not fully understood. To date, plentiful evidence has showed that metabolic alterations associated with obesity and related issues such as neuroinflammation, oxidative stress and mitochondrial dysfunction may represent an important risk factor, linking obesity and NDDs. Numerous studies have indicated a correlation between diet and brain activities. In this context, a key role is played by mitochondria located in the synaptic fraction; indeed, it has been shown that high-fat diets cause their dysfunction, affecting synaptic plasticity. In this scenario, the use of natural molecules that improve brain mitochondrial function represents an important therapeutic approach to treat NDDs. Recently, it was demonstrated that butyrate, a short-chain fatty acid is capable of counteracting obesity in an animal model, modulating mitochondrial function. The aim of this study has been to evaluate the effects of butyrate on neuroinflammatory state, oxidative stress and mitochondrial dysfunction in the brain cortex and in the synaptic fraction of a mouse model of diet-induced obesity. Our data have shown that butyrate partially reverts neuroinflammation and oxidative stress in the brain cortex and synaptic area, improving mitochondrial function and efficiency.

The Hepatic Mitochondrial Alterations Exacerbate Meta-Inflammation in Autism Spectrum Disorders

The role of the liver in autism spectrum disorders (ASD), developmental disabilities characterized by impairments in social interactions and repetitive behavioral patterns, has been poorly investigated. In ASD, it has been shown a dysregulation of gut-brain crosstalk, a communication system able to influence metabolic homeostasis, as well as brain development, mood and cognitive functions. The liver, with its key role in inflammatory and metabolic states, represents the crucial metabolic organ in this crosstalk. Indeed, through the portal vein, the liver receives not only nutrients but also numerous factors derived from the gut and visceral adipose tissue, which modulate metabolism and hepatic mitochondrial functions. Here, we investigated, in an animal model of ASD (BTBR mice), the involvement of hepatic mitochondria in the regulation of inflammatory state and liver damage. We observed increased inflammation and oxidative stress linked to hepatic mitochondrial dysfunction, steatotic hepatocytes, and marked mitochondrial fission in BTBR mice. Our preliminary study provides a better understanding of the pathophysiology of ASD and could open the way to identifying hepatic mitochondria as targets for innovative therapeutic strategies for the disease.

Heart Mitochondrial Metabolic Flexibility and Redox Status Are Improved by Donkey and Human Milk Intake

The biological mechanisms linking nutrition and antioxidants content of the diet with cardiovascular protection are subject of intense investigation. It has been demonstrated that dietary supplementation with cow, donkey or human milk, characterized by distinct nutritional properties, triggers significant differences in the metabolic and inflammatory status through the modulation of hepatic and skeletal muscle mitochondrial functions. Cardiac mitochondria play a key role for energy-demanding heart functions, and their disfunctions is leading to pathologies. Indeed, an altered heart mitochondrial function and the consequent increased reactive oxygen species (ROS) production and inflammatory state, is linked to several cardiac diseases such as hypertension and heart failure. In this work it was investigated the impact of the milk consumption on heart mitochondrial functions, inflammation and oxidative stress. In addition, it was underlined the crosstalk between mitochondrial metabolic flexibility, lipid storage and redox status as control mechanisms for the maintenance of cardiovascular health.

Dietary Micronutrient Management to Treat Mitochondrial Dysfunction in Diet-Induced Obese Mice

Obesity and associated metabolic disturbances, which have been increasing worldwide in recent years, are the consequences of unhealthy diets and physical inactivity and are the main factors underlying non-communicable diseases (NCD). These diseases are now responsible for about three out of five deaths worldwide, and it has been shown that they depend on mitochondrial dysfunction, systemic inflammation and oxidative stress. It was also demonstrated that several nutritional components modulating these processes are able to influence metabolic homeostasis and, consequently, to prevent or delay the onset of NCD. An interesting combination of nutraceutical substances, named DMG-gold, has been shown to promote metabolic and physical wellness. The aim of this research was to investigate the metabolic, inflammatory and oxidative pathways modulated by DMG-gold in an animal model with diet-induced obesity. Our data indicate that DMG-gold decreases the metabolic efficiency and inflammatory state and acts as an antioxidant and detoxifying agent, modulating mitochondrial functions. Therefore, DMG-gold is a promising candidate in the prevention/treatment of NCD.

Deregulated Local Protein Synthesis in the Brain Synaptosomes of a Mouse Model for Alzheimer's Disease

While protein synthesis in neurons is largely attributed to cell body and dendrites, the capability of synaptic regions to synthesize new proteins independently of the cell body has been widely demonstrated as an advantageous mechanism subserving synaptic plasticity. Thus, the contribution that local protein synthesis at synapses makes to physiology and pathology of brain plasticity may be more prevalent than initially thought. In this study, we tested if local protein synthesis at synapses is deregulated in the brains of TgCRND8 mice, an animal model for Alzheimer's disease (AD) overexpressing mutant human amyloid precursor protein (APP). To this end, we used synaptosomes as a model system to study the functionality of the synaptic regions in mouse brains. Our results showed that, while TgCRND8 mice exhibit early signs of brain inflammation and deficits in learning, the electrophoretic profile of newly synthesized proteins in their synaptosomes was subtly different from that of the control mice. Interestingly, APP itself was, in part, locally synthesized in the synaptosomes, underscoring the potential importance of local translation at synapses. More importantly, after the contextual fear conditioning, de novo synthesis of some individual proteins was significantly enhanced in the synaptosomes of control animals, but the TgCRND8 mice failed to display such synaptic modulation by training. Taken together, our results demonstrate that synaptic synthesis of proteins is impaired in the brain of a mouse model for AD, and raise the possibility that this deregulation may contribute to the early progression of the pathology.

High-Fat Diet Induces Neuroinflammation and Mitochondrial Impairment in Mice Cerebral Cortex and Synaptic Fraction

Brain mitochondrial dysfunction is involved in the development of neurological and neurodegenerative diseases. Mitochondria specifically located at synapses play a key role in providing energy to support synaptic functions and plasticity, thus their defects may lead to synaptic failure, which is a common hallmark of neurodegenerative diseases. High-Fat Diet (HFD) consumption increases brain oxidative stress and impairs brain mitochondrial functions, although the underlying mechanisms are not completely understood. The aim of our study is to analyze neuroinflammation and mitochondrial dysfunctions in brain cortex and synaptosomal fraction isolated from a mouse model of diet-induced obesity. Male C57Bl/6 mice were divided into two groups fed a standard diet or HFD for 18 weeks. At the end of the treatment, inflammation (detected by ELISA), antioxidant state (measured by enzymatic activity), mitochondrial functions and efficiency (detected by oxidative capacity and Seahorse analysis), and brain-derived neurotrophic factor (BDNF) pathway (analyzed by western blot) were determined in brain cortex and synaptosomal fraction. In HFD animals, we observed an increase in inflammatory parameters and oxidative stress and a decrease in mitochondrial oxidative capacity both in the brain cortex and synaptosomal fraction. These alterations parallel with modulation of BDNF, a brain key signaling molecule that is linking synaptic plasticity and energy metabolism. Neuroinflammation HFD-dependent negatively affects BDNF pathway and mitochondrial activity in the brain cortex. The effect is even more pronounced in the synaptic region, where the impaired energy supply may have a negative impact on neuronal plasticity.

Milk From Cow Fed With High Forage/Concentrate Ratio Diet: Beneficial Effect on Rat Skeletal Muscle Inflammatory State and Oxidative Stress Through Modulation of Mitochondrial Functions and AMPK Activity

Milk and dairy products are relevant components of daily diet and are part of dietary recommendation in many countries due to their content of key nutrients. However, the relatively high content of saturated fat of the milk and its extensive usage for every age group raises concerns about its potential negative health effects. Therefore, in the last years, several researchers dedicated their attention to milk production and quality. Milk fatty acids profile depend on cow feeding and in particular on the type of forage and concentrate and forage/concentrate ratio. It was demonstrated that feeding dairy cows with a 70/30 forage/concentrate ratio yields milk with a low ω6:ω3 ratio and high CLA levels. In this work, we demonstrated that the supplementation of rats diet with this high forage milk (HFM) results, in the skeletal muscle of these animals, in a reduced lipid content and inflammation levels, and an improved mitochondrial lipid oxidation, and redox status through modulation of AMPK activity.

N-Acetylcysteine protects against intrauterine growth retardation-induced intestinal injury via restoring redox status and mitochondrial function in neonatal piglets

PURPOSE

Intrauterine growth retardation (IUGR) is detrimental to the intestinal development of neonates, yet satisfactory treatment strategies remain limited. This study was, therefore, conducted using neonatal piglets as a model to investigate the potential of N-acetylcysteine (NAC) to alleviate intestinal damage caused by IUGR.

METHODS

Seven normal birth weight (NBW) and fourteen IUGR neonatal male piglets were selected and then fed a basal milk diet (NBW-CON and IUGR-CON groups) or a basal milk diet supplemented with 1.2 g NAC per kg of diet (IUGR-NAC group) from 7 to 21 days of age (n = 7). Parameters associated with the severity of intestinal injury, villus morphology and ultrastructural structure, redox status, and mitochondrial function were analyzed.

RESULTS

Compared with the NBW-CON piglets, the IUGR-CON piglets exhibited decreased villus height and greater numbers of apoptotic cells in jejunum, along with the increases in malondialdehyde and protein carbonyl concentrations and a decreased adenosine triphosphate (ATP) content. Treatment with NAC significantly increased jejunal superoxide dismutase activity, reduced glutathione: oxidized glutathione ratio, and the mRNA abundance of nuclear respiratory factor 2, heme oxygenase 1, and superoxide dismutase 2 in the IUGR-NAC piglets compared with the IUGR-CON piglets. In addition, NAC improved the efficiency of mitochondrial oxidative metabolism and ATP generation, ameliorated mitochondrial swelling, and inhibited the overproduction of mitochondrial superoxide anion in the jejunal mucosa.

CONCLUSIONS

Dietary supplementation of NAC shows promise for attenuating the early intestinal injury of young piglets with IUGR, probably through its antioxidant action to restore redox status and mitochondrial function.

Long Feeding High-Fat Diet Induces Hypothalamic Oxidative Stress and Inflammation, and Prolonged Hypothalamic AMPK Activation in Rat Animal Model

Scope: The hypothalamus is a key brain region involved in the control of feeding and energy expenditure. Hypothalamic inflammation and oxidative stress are landmarks of both obesity and aging processes, although the molecular mechanisms are still unknown. Therefore, with the aim to understand the neurobiological mechanisms of energy homeostasis during aging, we evaluate the effects of long feeding high-fat diet (HFD) in rats, at different age, on modulation of hypothalamic molecular pathway, oxidative stress, and inflammation.

Procedures: Male Wistar rats were divided into two groups: control group, receiving standard diet (CD), and treated group, receiving HFD. Both groups were treated with the appropriate diet for 1, 3, 6, 12, or 18 weeks. We investigated energy balance and body composition, as well as lipid profile, homeostatic model assessment index, and inflammatory state in serum. Furthermore, we also analyzed, at hypothalamic level, inflammation and oxidative stress, and adenosine monophosphate-dependent kinase (AMPK) and pAMPK expression levels.

Results: Our data showed that aging and HFD induce increased energy intake and energy efficiency and decreased energy expenditure associated, at hypothalamic level, with inflammation and oxidative stress and activation of AMPK.

Conclusion: Our results indicate that the age at which HFD feeding starts and the diet duration are critical in obesity development. The prolonged activation of hypothalamic AMPK may be related to the alterations in energy homeostasis.

Progressive DNA and RNA damage from oxidation after aneurysmal subarachnoid haemorrhage in humans

Free radical toxicity is considered as a key mechanism in the neuronal damage occurring after aneurysmal subarachnoid haemorrhage (SAH). We measured markers of DNA and RNA damage from oxidation (8-oxodG and 8-oxoGuo, respectively) in cerebrospinal fluid from 45 patients with SAH on day 1-14 after ictus and 45 age-matched healthy control subjects. At baseline, both markers were significantly increased in patients compared to controls (p values < .001), and exhibited a progressive further increase (to >20-fold above control levels) from day 5-14. None of the markers predicted the occurrence of vasospasms or mortality, although there was a trend that the 8-oxoGuo marker was more strongly associated with mortality than the 8-oxodG marker. We conclude that SAH leads to a massive increase in damage to nucleic acids from oxidative stress, which is likely to play a role in neuronal dysfunction and death. As only patients in need of a ventriculostomy catheter were included in the study, the findings cannot necessarily be extrapolated to all patients with SAH.

Heparin and Heparin-Derivatives in Post-Subarachnoid Hemorrhage Brain Injury: A Multimodal Therapy for a Multimodal Disease

Pharmacologic efforts to improve outcomes following aneurysmal subarachnoid hemorrhage (aSAH) remain disappointing, likely owing to the complex nature of post-hemorrhage brain injury. Previous work suggests that heparin, due to the multimodal nature of its actions, reduces the incidence of clinical vasospasm and delayed cerebral ischemia that accompany the disease. This narrative review examines how heparin may mitigate the non-vasospastic pathological aspects of aSAH, particularly those related to neuroinflammation. Following a brief review of early brain injury in aSAH and heparin’s general pharmacology, we discuss potential mechanistic roles of heparin therapy in treating post-aSAH inflammatory injury. These roles include reducing ischemia-reperfusion injury, preventing leukocyte extravasation, modulating phagocyte activation, countering oxidative stress, and correcting blood-brain barrier dysfunction. Following a discussion of evidence to support these mechanistic roles, we provide a brief discussion of potential complications of heparin usage in aSAH. Our review suggests that heparin’s use in aSAH is not only safe, but effectively addresses a number of pathologies initiated by aSAH.

Nrf2-ARE signaling provides neuroprotection in traumatic brain injury via modulation of the ubiquitin proteasome system

The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway exhibits protective effects in a variety of neurological diseases. However, the role of this pathway in traumatic brain injury (TBI) is not fully understood. This study investigates whether the Nrf2-ARE pathway provides neuroprotection following TBI via regulation of the ubiquitin proteasome system (UPS), and examines the involvement of this pathway in redox homeostasis. We found that activation the Nrf2-ARE pathway can mitigate secondary brain injury induced by TBI. Furthermore, we found that inhibiting the Nrf2-ARE pathway weakened the UPS following TBI. Treatment of TBI with the proteasome inhibitor, MG132, increased neuronal apoptosis, and evidence of brain water content was found. These data suggest that the Nrf2-ARE pathway provides neuroprotection following TBI via modulation of the UPS. In addition, the results indicated that the content of glutathione (GSH) was significantly increased after activation of Nrf2, and the level of ROS decreased; however, this effect contradictory in the Nrf2 knockout mice. Further studies found that treatment with the ROS agonist, ferric ammonium citrate (FAC), resulted in additional damage exerted by the ubiquitin proteasome pathways, and a significant increase in the amount of ubiquitinated proteins. In contrast, the activity of the ubiquitin proteasome pathways was vastly enhanced, and the level of ubiquitination proteins was significantly decreased following treatment with the inhibitor, N-acetylcysteine (NAC). The above mentioned results were also verified in in vitro experiments. In conclusion, the activation the Nrf2-ARE pathway improves neurological impairment caused by TBI via modulation of the UPS, and the redox homeostasis is one of the vital regulatory mechanisms.

Effects of an High-Fat Diet Enriched in Lard or in Fish Oil on the Hypothalamic Amp-Activated Protein Kinase and Inflammatory Mediators

The high fat diet (HFD) rich in lard induces obesity, inflammation and oxidative stress, and the deregulation of hypothalamic nuclei plays an important role in this mechanism. One important factor involved in the food intake and inflammation is adenosine monophosphate-dependent kinase (AMPK), a serine/threonine kinase activated by phosphorylation. Omega (ω)3-polyunsaturated fatty acids (PUFA) are dietary compounds known to attenuate the obesity-related diseases, although the molecular mechanisms underlying their actions in the hypothalamus are not completely understood. We hypothesized that the beneficial effects of PUFA may be mediated by AMPK in the hypothalamus. To this aim, rats were fed a control diet (CD), or isocaloric HFD containing either fish oil (FD; rich in ω3-PUFA) or lard for 6 weeks, and the activation of AMPK, inflammatory state (IKKβ, TNF-α) and oxidative stress were analyzed in the hypothalamus. In addition, we also studied serum lipid profile, homeostatic model assessment (HOMA) index, and pro-inflammatory parameters. Our results showed, at the hypothalamic level of LD-fed rats, an increase of AMPK activation, inflammation and oxidative stress, while no modifications were detected in FD-fed animals compared to CD. In addition body weight gain, serum lipid profile, pro-inflammatory parameters and insulin resistance were reduced in FD animals compared to LD. In conclusion, our data indicate that the substitution of saturated by unsaturated fatty acids in the diet has beneficial effects on modulation of hypothalamic inflammation and function in obesity, underlying, at hypothalamic level, the interaction among insulin and/or leptin resistance, AMPK activation and hyperphagia.

Dimethylfumarate alleviates early brain injury and secondary cognitive deficits after experimental subarachnoid hemorrhage via activation of Keap1-Nrf2-ARE system

OBJECT

Oxidative stress and the inflammatory response are thought to promote brain damage in the setting of subarachnoid hemorrhage (SAH). Previous reports have shown that dimethylfumarate (DMF) can activate the Kelch-like ECH-associated protein 1-nuclear factor erythroid 2-related factor 2-antioxidant-responsive element (Keap1-Nrf2-ARE) system in vivo and in vitro, which leads to the downregulation of oxidative stress and inflammation. The aim of this study was to evaluate the potential neuroprotective effect of DMF on SAH-induced brain injury in rats.

METHODS

Rats were subjected to SAH by the injection of 300 μl of autologous blood into the chiasmatic cistern. Rats in a DMF-treated group were given 15 mg/kg DMF twice daily by oral gavage for 2 days after the onset of SAH. Cortical apoptosis, neural necrosis, brain edema, blood-brain barrier impairment, learning deficits, and changes in the Keap1-Nrf2-ARE pathway were assessed.

RESULTS

Administration of DMF significantly ameliorated the early brain injury and learning deficits induced by SAH in this animal model. Treatment with DMF markedly upregulated the expressions of agents related to Keap1-Nrf2-ARE signaling after SAH. The inflammatory response and oxidative stress were downregulated by DMF therapy.

CONCLUSIONS

DMF administration resulted in abatement of the development of early brain injury and cognitive dysfunction in this prechiasmatic cistern SAH model. This result was probably mediated by the effect of DMF on the Keap1-Nrf2-ARE system.

Carnosine attenuates early brain injury through its antioxidative and anti-apoptotic effects in a rat experimental subarachnoid hemorrhage model

Carnosine (β-alanyl-L-histidine) has been demonstrated to provide antioxidative and anti-apoptotic roles in the animal of ischemic brain injuries and neurodegenerative diseases. The aim of this study was to examine whether carnosine prevents subarachnoid hemorrhage (SAH)-induced early brain injury (EBI) in rats. We found that intraperitoneal administration of carnosine improved neurobehavioral deficits, attenuated brain edema and blood-brain barrier permeability, and decreased reactive oxygen species level at 48 h following SAH in rat models. Carnosine treatment increased tissue copper/zinc superoxide dismutase (CuZn-SOD) and glutathione peroxidase (GSH-Px) enzymatic activities, and reduced post-SAH elevated lactate dehydrogenase (LDH) activity, the concentration of malondialdehyde (MDA), 3-nitrotyrosine (3-NT), 8-hydroxydeoxyguanosine (8-OHDG), interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) in rats. Furthermore, carnosine treatment attenuated SAH-induced microglia activation and cortical neuron apoptosis. These results indicated that administration of carnosine may provide neuroprotection in EBI following SAH in rat models.

Early brain injury, an evolving frontier in subarachnoid hemorrhage research

Subarachnoid hemorrhage (SAH), predominantly caused by a ruptured aneurysm, is a devastating neurological disease that has a morbidity and mortality rate higher than 50%. Most of the traditional in vivo research has focused on the pathophysiological or morphological changes of large-arteries after intracisternal blood injection. This was due to a widely held assumption that delayed vasospasm following SAH was the major cause of delayed cerebral ischemia and poor outcome. However, the results of the CONSCIOUS-1 trial implicated some other pathophysiological factors, independent of angiographic vasospasm, in contributing to the poor clinical outcome. The term early brain injury (EBI) has been coined and describes the immediate injury to the brain after SAH, before onset of delayed vasospasm. During the EBI period, a ruptured aneurysm brings on many physiological derangements such as increasing intracranial pressure (ICP), decreased cerebral blood flow (CBF), and global cerebral ischemia. These events initiate secondary injuries such as blood-brain barrier disruption, inflammation, and oxidative cascades that all ultimately lead to cell death. Given the fact that the reversal of vasospasm does not appear to improve patient outcome, it could be argued that the treatment of EBI may successfully attenuate some of the devastating secondary injuries and improve the outcome of patients with SAH. In this review, we provide an overview of the major advances in EBI after SAH research.

Tert-butylhydroquinone alleviates early brain injury and cognitive dysfunction after experimental subarachnoid hemorrhage: role of Keap1/Nrf2/ARE pathway

Tert-butylhydroquinone (tBHQ), an Nrf2 activator, has demonstrated neuroprotection against brain trauma and ischemic stroke in vivo. However, little work has been done with respect to its effect on early brain injury (EBI) after subarachnoid hemorrhage (SAH). At the same time, as an oral medication, it may have extensive clinical applications for the treatment of SAH-induced cognitive dysfunction. This study was undertaken to evaluate the influence of tBHQ on EBI, secondary deficits of learning and memory, and the Keap1/Nrf2/ARE pathway in a rat SAH model. SD rats were divided into four groups: (1) Control group (n=40); (2) SAH group (n=40); (3) SAH+vehicle group (n=40); and (4) SAH+tBHQ group (n=40). All SAH animals were subjected to injection of autologous blood into the prechiasmatic cistern once in 20 s. In SAH+tBHQ group, tBHQ was administered via oral gavage at a dose of 12.5 mg/kg at 2 h, 12 h, 24 h, and 36 h after SAH. In the first set of experiments, brain samples were extracted and evaluated 48 h after SAH. In the second set of experiments, changes in cognition and memory were investigated in a Morris water maze. Results shows that administration of tBHQ after SAH significantly ameliorated EBI-related problems, such as brain edema, blood-brain barrier (BBB) impairment, clinical behavior deficits, cortical apoptosis, and neurodegeneration. Learning deficits induced by SAH was markedly alleviated after tBHQ therapy. Treatment with tBHQ markedly up-regulated the expression of Keap1, Nrf2, HO-1, NQO1, and GSTα1 after SAH. In conclusion, the administration of tBHQ abated the development of EBI and cognitive dysfunction in this SAH model. Its action was probably mediated by activation of the Keap1/Nrf2/ARE pathway.

Protective effect of quercetin against oxidative stress and brain edema in an experimental rat model of subarachnoid hemorrhage

Quercetin has been demonstrated to play an important role in altering the progression of ischemic brain injuries and neurodegenerative diseases by protecting against oxidative stress. The effects of quercetin on brain damage after subarachnoid hemorrhage (SAH), however, have not been investigated. This study was designed to explore the effects of quercetin on oxidative stress and brain edema after experimental SAH using four equal groups (n = 16) of adult male Sprague-Dawley (SD) rats, including a sham group, an SAH + vehicle group, an SAH + quercetin10 group, and an SAH + quercetin50 group. The rat SAH model was induced by injection of 0.3 ml of non-heparinised arterial blood into the prechiasmatic cistern. In the SAH + quercetin10 and SAH + quercetin50 groups, doses of 10 mg/kg and 50 mg/kg quercetin, respectively, were directly administered by intraperitoneal injection at 30 min, 12 h, and 24 h after SAH induction. Cerebral tissue samples were extracted for enzymatic antioxidant determination, lipid peroxidation assay, caspase-3 activity and water content testing 48 h after SAH. Treatment with a high dose (50 mg/kg) of quercetin markedly enhanced the activities of copper/zinc superoxide dismutase (CuZn-SOD) and glutathione peroxidase (GSH-Px), and treatment with this dose significantly reduced the level of malondialdehyde (MDA). Caspase-3 and brain edema was ameliorated and neurobehavioral deficits improved in rats that received the high dose of quercetin. The findings suggest that the early administration of optimal dose of quercetin may ameliorate brain damage and provide neuroprotection in the SAH model, potentially by enhancing the activity of endogenous antioxidant enzymes and inhibiting free radical generation.

Reprint of: Neuroinflammation in acute liver failure: mechanisms and novel therapeutic targets

It is increasingly evident that neuroinflammatory mechanisms are implicated in the pathogenesis of the central nervous system (CNS) complications (intracranial hypertension, brain herniation) of acute liver failure (ALF). Neuroinflammation in ALF is characterized by microglial activation and arterio-venous difference studies as well as studies of gene expression confirm local brain production and release of proinflammatory cytokines including TNF-α and the interleukins IL-1β and IL-6. Although the precise nature of the glial cell responsible for brain cytokine synthesis is not yet established, evidence to date supports a role for both astrocytes and microglia. The neuroinflammatory response in ALF progresses in parallel with the progression of hepatic encephalopathy (HE) and with the severity of brain edema (astrocyte swelling). Mechanisms responsible for the relaying of signals from the failing liver to the brain include transduction of systemic proinflammatory signals as well as the effects of increased brain lactate leading to increased release of cytokines from both astrocytes and microglia. There is evidence in support of a synergistic effect of proinflammatory cytokines and ammonia in the pathogenesis of HE and brain edema in ALF. Therapeutic implications of the findings of a neuroinflammatory response in ALF are multiple. Removal of both ammonia and proinflammatory cytokines is possible using antibiotics or albumen dialysis. Mild hypothermia reduces brain ammonia transfer, brain lactate production, microglial activation and proinflammatory cytokine production resulting in reduced brain edema and intracranial pressure in ALF. N-Acetylcysteine acts as both an antioxidant and anti-inflammatory agent at both peripheral and central sites of action independently resulting in slowing of HE progression and prevention of brain edema. Novel treatments that directly target the neuroinflammatory response in ALF include the use of etanercept, a TNF-α neutralizing molecule and minocycline, an agent with potent inhibitory actions on microglial activation that are independent of its antimicrobial properties; both agents have been shown to be effective in reducing neuroinflammation and in preventing the CNS complications of ALF. Translation of these findings to the clinic has the potential to provide rational targeted approaches to the prevention and treatment of these complications in the near future.

N-Acetylcysteine reverses mitochondrial dysfunctions and behavioral abnormalities in 3-nitropropionic acid-induced Huntington's disease

Mitochondrial dysfunction is a major event involved in the pathogenesis of Huntington's disease (HD). The present study evaluates the role of N-acetyl-L-cysteine (NAC) in preventing mitochondrial dysfunctions in a 3-nitropropionic acid (3-NP)-induced model of HD. Administration of 3-NP to rats (Wistar strain) resulted in significant inhibition of mitochondrial complexes II, IV and V in the striatum. However, no significant effect on complex I was observed. Increased generation of reactive oxygen species and lipid peroxidation was observed in mitochondria of 3-NP-treated animals. Endogenous antioxidants (thiols and manganese-superoxide dismutase) were lowered in mitochondria of 3-NP-treated animals. 3-NP-treated animals showed increased cytosolic cytochrome c levels and mitochondrial swelling. Increased expressions of caspase-3 and p53 were also observed in 3-NP-treated animals. Histopathological examination of the striata of 3-NP-treated animals revealed increased neural space, neurodegeneration and gliosis. This was accompanied by cognitive and motor deficits. NAC treatment, on the other hand, was found to be effective in reversing 3-NP-induced mitochondrial dysfunctions and neurobehavioral deficits. Our findings suggest a beneficial effect of NAC in HD.

Effect of N-acetylcysteine on vasospasm in subarachnoid hemorrhage

Vasospasm remains an extremely serious complication that affects patients presenting with subarachnoid hemorrhage (SAH) due to ruptured intracranial aneurysms. The current therapeutic armamentarium is still insufficient in many cases, and the search for new therapies is necessary. In this study, we evaluated the effect of N-acetylcysteine (NAC) on cerebral arterial vasospasm using an experimental model. Twenty-four wistar rats were divided into 4 groups: [1] Control, [2] SAH, [3] SAH+NAC and [4] SAH+Placebo. The experimental model employed double subarachnoid injections of autologous blood. The proposed dose of NAC was 250 mg/kg intraperitoneally per day. We analyzed the inner area of the basilar artery to assess the action of NAC. The experimental model proved to be very adequate, with a mortality rate of 4%. The inner area of the basilar artery in the SAH group showed significant difference to the control group (p=0.009). The use of NAC significantly reduced vasospasm as compared to the untreated group (p=0.048) and established no significant difference to the control group (p=0.098). There was no significant improvement with the administration of placebo (p=0.97). The model of the dual hemorrhage proved to be very useful for vasospasm simulation, with overall low mortality. The administration of NAC significantly reduced vasospasm resulting from SAH, and may represent a new therapeutic alternative.

Neuroinflammation in acute liver failure: mechanisms and novel therapeutic targets

It is increasingly evident that neuroinflammatory mechanisms are implicated in the pathogenesis of the central nervous system (CNS) complications (intracranial hypertension, brain herniation) of acute liver failure (ALF). Neuroinflammation in ALF is characterized by microglial activation and arterio-venous difference studies as well as studies of gene expression confirm local brain production and release of proinflammatory cytokines including TNF-α and the interleukins IL-1β and IL-6. Although the precise nature of the glial cell responsible for brain cytokine synthesis is not yet established, evidence to date supports a role for both astrocytes and microglia. The neuroinflammatory response in ALF progresses in parallel with the progression of hepatic encephalopathy (HE) and with the severity of brain edema (astrocyte swelling). Mechanisms responsible for the relaying of signals from the failing liver to the brain include transduction of systemic proinflammatory signals as well as the effects of increased brain lactate leading to increased release of cytokines from both astrocytes and microglia. There is evidence in support of a synergistic effect of proinflammatory cytokines and ammonia in the pathogenesis of HE and brain edema in ALF. Therapeutic implications of the findings of a neuroinflammatory response in ALF are multiple. Removal of both ammonia and proinflammatory cytokines is possible using antibiotics or albumen dialysis. Mild hypothermia reduces brain ammonia transfer, brain lactate production, microglial activation and proinflammatory cytokine production resulting in reduced brain edema and intracranial pressure in ALF. N-Acetylcysteine acts as both an antioxidant and anti-inflammatory agent at both peripheral and central sites of action independently resulting in slowing of HE progression and prevention of brain edema. Novel treatments that directly target the neuroinflammatory response in ALF include the use of etanercept, a TNF-α neutralizing molecule and minocycline, an agent with potent inhibitory actions on microglial activation that are independent of its antimicrobial properties; both agents have been shown to be effective in reducing neuroinflammation and in preventing the CNS complications of ALF. Translation of these findings to the clinic has the potential to provide rational targeted approaches to the prevention and treatment of these complications in the near future.

Apoptotic mechanisms for neuronal cells in early brain injury after subarachnoid hemorrhage

OBJECTS

The major causes of death and disability in subarachnoid hemorrhage (SAH) may be early brain injury (EBI) and cerebral vasospasm. Although cerebral vasospasm has been studied and treated by a lot of drugs, the outcome is not improved even if vasospasm is reversed. Based on these data, EBI is considered a primary target for future research, and apoptosis may be involved in EBI after experimental SAH.

METHODS

We reviewed the published literature about the relationship between SAH induced EBI and apoptosis in PubMed.

RESULT

Most available information can be obtained from the endovascular filament perforation animal model. After onset of SAH, intracranial pressure is increased and then cerebral blood flow is reduced. Many factors are involved in the mechanism of apoptotic cell death in EBI after SAH. In the neuronal cells, both intrinsic and extrinsic pathways of apoptosis can occur. Some antiapoptotic drugs were studied and demonstrated a protective effect against EBI after SAH. However, apoptosis in EBI after SAH has been little studied and further studies will provide us more beneficial findings.

CONCLUSIONS

The study of apoptosis in EBI after experimental SAH may give us new therapies for SAH.

The anti-inflammatory and neuroprotective effects of ghrelin in subarachnoid hemorrhage-induced oxidative brain damage in rats

To elucidate the putative neuroprotective effects of ghrelin in subarachnoid hemorrhage (SAH)-induced brain injury, Wistar albino rats (n = 54) were divided into sham-operated control, saline-treated SAH, and ghrelin-treated (10 microg/kg/d IP) SAH groups. The rats were injected with blood (0.3 mL) into the cisterna magna to induce SAH, and were sacrificed 48 h after the neurological examination scores were recorded. In plasma samples, neuron-specific enolase (NSE), S-100beta protein, TNF-alpha, and IL-1beta levels were evaluated, while forebrain tissue samples were taken for the measurement of malondialdehyde (MDA), glutathione (GSH), reactive oxygen species levels, myeloperoxidase (MPO), Na(+)-K(+)-ATPase activity, and DNA fragmentation ratio. Brain tissue samples containing the basilar arteries were obtained for histological examination, while cerebrum and cerebellum were removed for the measurement of blood-brain barrier (BBB) permeability and brain water content. The neurological scores were impaired at 48 h after SAH induction, and SAH caused significant decreases in brain GSH content and Na(+)-K(+)-ATPase activity, and increases in chemiluminescence, MDA levels, and MPO activity. Compared with the control group, the protein levels of NSE, S-100beta, TNF-alpha, and IL-1beta in plasma were also increased, while ghrelin treatment prevented all SAH-induced alterations observed both biochemically and histopathologically. The results demonstrate that ghrelin alleviates SAH-induced oxidative brain damage, and exerts neuroprotection by maintaining a balance in oxidant-antioxidant status, by inhibiting proinflammatory mediators, and preventing the depletion of endogenous antioxidants evoked by SAH.

Up-regulation of caveolin-1 and blood-brain barrier breakdown are attenuated by N-acetylcysteine in thiamine deficiency

Wernicke's encephalopathy is a cerebral metabolic disorder caused by thiamine (vitamin B1) deficiency (TD). Neuropathologic consequences of TD include region-selective neuronal cell loss and blood-brain barrier (BBB) breakdown. Caveolin-1 is involved in the regulation of tight junction proteins and BBB permeability, and is modulated by oxidative stress, a feature of vulnerable brain regions in TD. We hypothesized that TD-related oxidative stress alters BBB integrity via induction of the caveolin-1 pathway. TD was induced in C57BL6 mice by treatment with a thiamine-deficient diet and administration of the thiamine antagonist pyrithiamine, in the absence or presence of the antioxidant N-acetylcysteine (NAC). A significant and focal increase in both caveolin-1 gene and protein expression was detected in the thalamus of thiamine-deficient mice, concomitant with IgG extravasation. Reduction of oxidative stress by NAC, as shown by normalization of reduced glutathione levels and attenuation of endothelial heme oxygenase-1 and nitric oxide synthase expression, resulted in prevention of the up-regulation of caveolin-1 in TD. Normalization of caveolin-1 levels by NAC was accompanied by a reduction in BBB breakdown, indicated by decreased IgG extravasation, normalization of occludin levels and prevention of matrix metalloproteinase-9 up-regulation. These findings demonstrate a role for caveolin-1 in TD pathogenesis, and suggest that oxidative stress contributes to BBB alterations in TD via modulation of this pathway.

Influence of melatonin on cerebrovascular proinflammatory mediators expression and oxidative stress following subarachnoid hemorrhage in rabbits

The aim of this study is to analyze whether melatonin administration influenced the nuclear factor-kappa B (NF-κB) activity, proinflammatory cytokines expression, and oxidative response in the basilar artery after SAH. A total of 48 rabbits were randomly divided into four groups: control group, SAH group, SAH + vehicle group, and SAH + melatonin group. All SAH animals were subjected to injection of autologous blood into cisterna magna twice on day 0 and day 2. The melatonin was administered intraperitoneally at a dose of 5 mg/kg/12 h simultaneously with SAH from day 0 to day 5. The basilar arteries were extracted on day 5 after SAH. As a result, we found that vascular inflammation and oxidative stress were induced in all SAH animals. In animals given melatonin, basilar arterial NF-κB and pro-inflammatory cytokines were decreased in comparison to vehicle-treated animals. Measures of oxidative stress also showed significant downregulation after melatonin treatment. Furthermore, administration of melatonin prevented vasospasm on day 5 following SAH. In conclusion, post-SAH melatonin administration may attenuate inflammatory response and oxidative stress in the spasmodic artery, and this may be one mechanism involved in the therapeutic effect of melatonin on the subsequent vasospasm after SAH.