The therapy of many neurological disorders has advanced markedly during recent decades. Not so for neurodegenerative disorders. Early detection, deep individual genotyping and phenotyping, and personalized therapies have been suggested as the way forward. However, we still do not know enough about the aetiology and molecular basics of these diseases. In fact, the term neurodegenerative disorder may be a misleading categorization that constitutes a major cognitive barrier against better characterization and understanding of these disorders. Therefore, we need to go back to the basics and employ novel, open-minded observational study protocols that combine very extensive and robust clinical, molecular and epidemiological data collection methods. Moreover, we need to reconsider our basic orientation towards these diseases to increase our chances of finding out what we are actually trying to care for and cure.
The therapy of many neurological disorders has advanced markedly during recent decades. Not so for neurodegenerative disorders. Early detection, deep individual genotyping and phenotyping, and personalized therapies have been suggested as the way forward. However, we still do not know enough about the aetiology and molecular basics of these diseases. In fact, the term neurodegenerative disorder may be a misleading categorization that constitutes a major cognitive barrier against better characterization and understanding of these disorders. Therefore, we need to go back to the basics and employ novel, open-minded observational study protocols that combine very extensive and robust clinical, molecular and epidemiological data collection methods. Moreover, we need to reconsider our basic orientation towards these diseases to increase our chances of finding out what we are actually trying to care for and cure.
DOI: https://doi.org/10.37349/en.2022.00006
Stroke is a leading cause of morbidity and mortality. The advent of mechanical thrombectomy has largely improved patient outcomes. This article reviews the features and outcomes associated with aspiration, stent retrievers, and combination catheters used in current practice. There is also a discussion on clinical considerations based on anatomical features and clot composition. The reperfusion grading scale and outcome metrics commonly used following thrombectomy when a patient is still in the hospital are reviewed. Lastly, there are proposed discharge and outpatient follow-up goals in caring for patients hospitalized for a stroke.
Stroke is a leading cause of morbidity and mortality. The advent of mechanical thrombectomy has largely improved patient outcomes. This article reviews the features and outcomes associated with aspiration, stent retrievers, and combination catheters used in current practice. There is also a discussion on clinical considerations based on anatomical features and clot composition. The reperfusion grading scale and outcome metrics commonly used following thrombectomy when a patient is still in the hospital are reviewed. Lastly, there are proposed discharge and outpatient follow-up goals in caring for patients hospitalized for a stroke.
DOI: https://doi.org/10.37349/en.2022.00007
Exposure to stressful conditions plays a critical role in brain processes, including neural plasticity, synaptic transmission, and cognitive functions. Since memory-related brain regions, the hippocampus (Hip), the amygdala, and the prefrontal cortex, express high glucocorticoid receptors (GRs), these areas are the potential targets of stress hormones. Stress affects memory encoding, consolidation, and retrieval, which may depend on many factors such as the type, duration, the intensity of the stressor or the brain region. Here, this review mainly focused on the mechanisms involved in stress-induced memory impairment. Acute/chronic stress induces structural and functional changes in neurons and glial cells. Dendritic arborization, reduction of dendritic spine density, and alteration in glutamatergic-mediated synaptic transmission via N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors are mechanisms that stress affect long-term memory formation. Exposure to acute or chronic stress could interplay with multiple neurotransmitter signaling, modulating the neuronal circuits involved in memory impairment or state-dependent learning. Stress hormones also modulate the expression of microRNAs in the specific brain regions responsible for stress-induced behaviors. Because of expressing GRs in astrocytes and microglial cells, stress could affect the morphology, structure, and functions of these glial cells in memory-related brain regions. Astrocytes play a crucial role in stress-induced aversive or fear memory formation. Over-activation of the microglial cells enhances the release of inflammatory cytokines, which results in neuronal injury. Stress has a prominent role in cognitive decline to induces memory problems, particularly in older adults. Due to the issue’s importance, here the provided overview attempted to address the question of how stress alters neuronal epigenetic regulators, synaptic transmissions, and glial activity in the brain.
Exposure to stressful conditions plays a critical role in brain processes, including neural plasticity, synaptic transmission, and cognitive functions. Since memory-related brain regions, the hippocampus (Hip), the amygdala, and the prefrontal cortex, express high glucocorticoid receptors (GRs), these areas are the potential targets of stress hormones. Stress affects memory encoding, consolidation, and retrieval, which may depend on many factors such as the type, duration, the intensity of the stressor or the brain region. Here, this review mainly focused on the mechanisms involved in stress-induced memory impairment. Acute/chronic stress induces structural and functional changes in neurons and glial cells. Dendritic arborization, reduction of dendritic spine density, and alteration in glutamatergic-mediated synaptic transmission via N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors are mechanisms that stress affect long-term memory formation. Exposure to acute or chronic stress could interplay with multiple neurotransmitter signaling, modulating the neuronal circuits involved in memory impairment or state-dependent learning. Stress hormones also modulate the expression of microRNAs in the specific brain regions responsible for stress-induced behaviors. Because of expressing GRs in astrocytes and microglial cells, stress could affect the morphology, structure, and functions of these glial cells in memory-related brain regions. Astrocytes play a crucial role in stress-induced aversive or fear memory formation. Over-activation of the microglial cells enhances the release of inflammatory cytokines, which results in neuronal injury. Stress has a prominent role in cognitive decline to induces memory problems, particularly in older adults. Due to the issue’s importance, here the provided overview attempted to address the question of how stress alters neuronal epigenetic regulators, synaptic transmissions, and glial activity in the brain.
DOI: https://doi.org/10.37349/en.2022.00008
Astrocytomas include a wide range of tumors with unique mutations and varying grades of malignancy. These tumors all originate from the astrocyte, a star-shaped glial cell that plays a major role in supporting functions of the central nervous system (CNS), including blood-brain barrier (BBB) development and maintenance, water and ion regulation, influencing neuronal synaptogenesis, and stimulating the immunological response. In terms of epidemiology, glioblastoma (GB), the most common and malignant astrocytoma, generally occur with higher rates in Australia, Western Europe, and Canada, with the lowest rates in Southeast Asia. Additionally, significantly higher rates of GB are observed in males and non-Hispanic whites. It has been suggested that higher levels of testosterone observed in biological males may account for the increased rates of GB. Hereditary syndromes such as Cowden, Lynch, Turcot, Li-Fraumeni, and neurofibromatosis type 1 have been linked to increased rates of astrocytoma development. While there are a number of specific gene mutations that may influence malignancy or be targeted in astrocytoma treatment, O6-methylguanine-DNA methyltransferase (MGMT) gene function is an important predictor of astrocytoma response to chemotherapeutic agent temozolomide (TMZ). TMZ for primary and bevacizumab in the setting of recurrent tumor formation are two of the main chemotherapeutic agents currently approved in the treatment of astrocytomas. While stereotactic radiosurgery (SRS) has debatable implications for increased survival in comparison to whole-brain radiotherapy (WBRT), SRS demonstrates increased precision with reduced radiation toxicity. When considering surgical resection of astrocytoma, the extent of resection (EoR) is taken into consideration. Subtotal resection (STR) spares the margins of the T1 enhanced magnetic resonance imaging (MRI) region, gross total resection (GTR) includes the margins, and supramaximal resection (SMR) extends beyond the margin of the T1 and into the T2 region. Surgical resection, radiation, and chemotherapy are integral components of astrocytoma treatment.
Hereditary risk factors, genetic mutations, and imaging modalities are discussed in reference to astrocytoma staging and mechanism of growth. In terms of the treatment of astrocytomas, chemotherapy, radiation therapy, and strategic surgical interventions are discussed
Astrocytomas include a wide range of tumors with unique mutations and varying grades of malignancy. These tumors all originate from the astrocyte, a star-shaped glial cell that plays a major role in supporting functions of the central nervous system (CNS), including blood-brain barrier (BBB) development and maintenance, water and ion regulation, influencing neuronal synaptogenesis, and stimulating the immunological response. In terms of epidemiology, glioblastoma (GB), the most common and malignant astrocytoma, generally occur with higher rates in Australia, Western Europe, and Canada, with the lowest rates in Southeast Asia. Additionally, significantly higher rates of GB are observed in males and non-Hispanic whites. It has been suggested that higher levels of testosterone observed in biological males may account for the increased rates of GB. Hereditary syndromes such as Cowden, Lynch, Turcot, Li-Fraumeni, and neurofibromatosis type 1 have been linked to increased rates of astrocytoma development. While there are a number of specific gene mutations that may influence malignancy or be targeted in astrocytoma treatment, O6-methylguanine-DNA methyltransferase (MGMT) gene function is an important predictor of astrocytoma response to chemotherapeutic agent temozolomide (TMZ). TMZ for primary and bevacizumab in the setting of recurrent tumor formation are two of the main chemotherapeutic agents currently approved in the treatment of astrocytomas. While stereotactic radiosurgery (SRS) has debatable implications for increased survival in comparison to whole-brain radiotherapy (WBRT), SRS demonstrates increased precision with reduced radiation toxicity. When considering surgical resection of astrocytoma, the extent of resection (EoR) is taken into consideration. Subtotal resection (STR) spares the margins of the T1 enhanced magnetic resonance imaging (MRI) region, gross total resection (GTR) includes the margins, and supramaximal resection (SMR) extends beyond the margin of the T1 and into the T2 region. Surgical resection, radiation, and chemotherapy are integral components of astrocytoma treatment.
Hereditary risk factors, genetic mutations, and imaging modalities are discussed in reference to astrocytoma staging and mechanism of growth. In terms of the treatment of astrocytomas, chemotherapy, radiation therapy, and strategic surgical interventions are discussed
DOI: https://doi.org/10.37349/en.2023.00009
Aim:
Stroke is one of the leading causes of death and disability worldwide. Plasma biomarkers have long been used to evaluate physiological or pathological processes and to make predictions about the outcome of stroke patients. The current systematic review is focused on genetic plasma biomarkers as a new potential prognostic indicator for post-stroke recovery. The aim of the present systematic review is to assess the potential of genetic plasma biomarkers associated with stroke to predict post-stroke recovery.
Methods:
The search strategy used PubMed and Web of Science databases to identified 166 studies that investigated genetic plasma biomarkers in patients with stroke between 2017 and 2021. However, only 21 of them met the inclusion criteria.
Results:
The identified genetic biomarkers can be divided into: (i) serum/plasma circular RNA (circRNA) associated with stroke onset or recurrence (5; 23.80%), (ii) genetic polymorphisms associated with the atherosclerotic process and stroke recurrence (6; 28.57%), (iii) serum/plasma long non-coding RNA (lncRNA) levels involved in immunity/inflammatory processes (4; 19.04%), (iv) marker of DNA methylation associated with stroke onset and outcome (3; 14.28%), and (v) proteins and pathways of stroke identified by serum/ plasma proteomics/genomics analysis (3; 14.28%).
Conclusions:
Overall, more than 100 potential biomarkers were found and the data suggest that combinations of plasma genetic biomarkers might be used as a better predictor for stroke.
Aim:
Stroke is one of the leading causes of death and disability worldwide. Plasma biomarkers have long been used to evaluate physiological or pathological processes and to make predictions about the outcome of stroke patients. The current systematic review is focused on genetic plasma biomarkers as a new potential prognostic indicator for post-stroke recovery. The aim of the present systematic review is to assess the potential of genetic plasma biomarkers associated with stroke to predict post-stroke recovery.
Methods:
The search strategy used PubMed and Web of Science databases to identified 166 studies that investigated genetic plasma biomarkers in patients with stroke between 2017 and 2021. However, only 21 of them met the inclusion criteria.
Results:
The identified genetic biomarkers can be divided into: (i) serum/plasma circular RNA (circRNA) associated with stroke onset or recurrence (5; 23.80%), (ii) genetic polymorphisms associated with the atherosclerotic process and stroke recurrence (6; 28.57%), (iii) serum/plasma long non-coding RNA (lncRNA) levels involved in immunity/inflammatory processes (4; 19.04%), (iv) marker of DNA methylation associated with stroke onset and outcome (3; 14.28%), and (v) proteins and pathways of stroke identified by serum/ plasma proteomics/genomics analysis (3; 14.28%).
Conclusions:
Overall, more than 100 potential biomarkers were found and the data suggest that combinations of plasma genetic biomarkers might be used as a better predictor for stroke.
DOI: https://doi.org/10.37349/en.2023.00010
This article belongs to the special issue Cerebral Ischemia, Genetics, Comorbidities, Risk Factors and New Therapeutic Options for Neurorestoration
DOI: https://doi.org/10.37349/en.2023.00011
Aim:
Microglial activation is increasingly recognised as a factor in the progression of Alzheimer’s disease (AD) and may be modified by systemic inflammatory signals including serum tumour necrosis factor (TNF)-α. The aim was to investigate whether blockade of peripheral TNF-α with peripheral inhibitors such as etanercept reduces microglial activation in prodromal AD.
Methods:
A one-year, multi-centre, phase 2, double-blind randomised placebo-controlled trial (RPCT) was performed, to assess the effect of weekly 50 mg s.c. etanercept in amyloid positive mild cognitive impaired participants on the change in microglial activation as measured by [11C](R)-PK11195 positron emission tomography (PET). Secondary objectives were to ascertain the change in cortical amyloid load on PET and the change in the Montreal Cognitive Assessment (MoCA).
Results:
Forty-four subjects consented to the study. Twenty-eight subjects failed screening including six subjects who were amyloid negative on visual read of the AmyvidTM PET scans. Thirteen of sixteen subjects with mild cognitive impairment (MCI) due to AD completed the baseline [11C](R)-PK11195 PET scan and were randomised to either placebo or etanercept. Three patients who consented were not able to complete screening due to early termination of the study following delays in study commencement. [11C](R)-PK11195 binding potential (BP) at baseline showed an almost global increase in MCI patients as compared to age-matched controls. Compliance to medication was high over the twelve-month trial period with etanercept being well tolerated. The study did not achieve statistical power to show a significant effect of etanercept over 52 weeks in the limited number of patients with MCI on microglial activation as measured by [11C](R)-PK11195 PET. Overall uptake of florbetapir in the follow up (FU) scans remained stable. The study was not powered to show statistical differences in psychometric ratings between groups.
Conclusions:
This study did not show evidence that treatment with etanercept over one year would modulate microglial activation in amyloid positive MCI patients (EudraCT identifier: 2015-002145-63, https://www.clinicaltrialsregister.eu; International Standard Randomised Controlled Trial Number identifier: ISRCTN12472821, https://www.isrctn.com).
Aim:
Microglial activation is increasingly recognised as a factor in the progression of Alzheimer’s disease (AD) and may be modified by systemic inflammatory signals including serum tumour necrosis factor (TNF)-α. The aim was to investigate whether blockade of peripheral TNF-α with peripheral inhibitors such as etanercept reduces microglial activation in prodromal AD.
Methods:
A one-year, multi-centre, phase 2, double-blind randomised placebo-controlled trial (RPCT) was performed, to assess the effect of weekly 50 mg s.c. etanercept in amyloid positive mild cognitive impaired participants on the change in microglial activation as measured by [11C](R)-PK11195 positron emission tomography (PET). Secondary objectives were to ascertain the change in cortical amyloid load on PET and the change in the Montreal Cognitive Assessment (MoCA).
Results:
Forty-four subjects consented to the study. Twenty-eight subjects failed screening including six subjects who were amyloid negative on visual read of the AmyvidTM PET scans. Thirteen of sixteen subjects with mild cognitive impairment (MCI) due to AD completed the baseline [11C](R)-PK11195 PET scan and were randomised to either placebo or etanercept. Three patients who consented were not able to complete screening due to early termination of the study following delays in study commencement. [11C](R)-PK11195 binding potential (BP) at baseline showed an almost global increase in MCI patients as compared to age-matched controls. Compliance to medication was high over the twelve-month trial period with etanercept being well tolerated. The study did not achieve statistical power to show a significant effect of etanercept over 52 weeks in the limited number of patients with MCI on microglial activation as measured by [11C](R)-PK11195 PET. Overall uptake of florbetapir in the follow up (FU) scans remained stable. The study was not powered to show statistical differences in psychometric ratings between groups.
Conclusions:
This study did not show evidence that treatment with etanercept over one year would modulate microglial activation in amyloid positive MCI patients (EudraCT identifier: 2015-002145-63, https://www.clinicaltrialsregister.eu; International Standard Randomised Controlled Trial Number identifier: ISRCTN12472821, https://www.isrctn.com).
DOI: https://doi.org/10.37349/en.2023.00012
Despite decades of intensive research, effective treatment and prevention strategies for neurodegenerative diseases (NDDs) remain elusive. This review focuses on Alzheimer’s and Parkinson’s diseases and acquired epilepsy suggesting that in their early phase, these progressive pathologies share common or interacting molecular pathways. Indeed, oxidative stress associated with disrupted glucose metabolism is the expected end state of most, if not all, risk factors preceding the onset of major NDDs. This review proposes that the initial oxidative stress in the brain resulting specifically from the hyperactivation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) causes a decline in glucose utilization and is the primary initiating factor of major NDDs. The existing clinical and experimental evidence points to NOX as the primary initiating mechanism shared within the major NDDs. During early oxidative stress, NOX activation is triggered in variable brain cells via multiple pathways, from beta-amyloid to alpha-synuclein, fibrin to glutamate and seizures. Therefore, the treatment strategy should have targeted the activation of NOX, wouldn’t there be a lack of clinically approved selective NOX antagonists? On the other hand, there are promising metabolism-altering approaches via dietary means able to switch energy intake from glucose to ketones, which influences both oxidative stress and glucose utilization and could ameliorate disease progression. The regimen of time-restricted eating appears to be the most feasible, nutritious, and palatable one providing the essential benefits of a ketogenic diet without adverse effects.
Despite decades of intensive research, effective treatment and prevention strategies for neurodegenerative diseases (NDDs) remain elusive. This review focuses on Alzheimer’s and Parkinson’s diseases and acquired epilepsy suggesting that in their early phase, these progressive pathologies share common or interacting molecular pathways. Indeed, oxidative stress associated with disrupted glucose metabolism is the expected end state of most, if not all, risk factors preceding the onset of major NDDs. This review proposes that the initial oxidative stress in the brain resulting specifically from the hyperactivation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) causes a decline in glucose utilization and is the primary initiating factor of major NDDs. The existing clinical and experimental evidence points to NOX as the primary initiating mechanism shared within the major NDDs. During early oxidative stress, NOX activation is triggered in variable brain cells via multiple pathways, from beta-amyloid to alpha-synuclein, fibrin to glutamate and seizures. Therefore, the treatment strategy should have targeted the activation of NOX, wouldn’t there be a lack of clinically approved selective NOX antagonists? On the other hand, there are promising metabolism-altering approaches via dietary means able to switch energy intake from glucose to ketones, which influences both oxidative stress and glucose utilization and could ameliorate disease progression. The regimen of time-restricted eating appears to be the most feasible, nutritious, and palatable one providing the essential benefits of a ketogenic diet without adverse effects.
DOI: https://doi.org/10.37349/en.2023.00013
DOI: https://doi.org/10.37349/en.2022.00001
All living organisms exhibit circadian rhythms. Humans show circadian rhythm of the different physiological functions such as sleep-wake cycle, core body temperature, feeding behavior, metabolic activity, heart rate variability, hormone secretion, and others. The hypothalamic suprachiasmatic nucleus (SCN) acts as a primary circadian pacemaker. Peripheral tissues have an endogenous circadian clock; however, SCN synchronizes the circadian activity of the peripheral clocks. The retinohypothalamic tract (RHT) from retinal ganglionic cells carries the photic signal into the SCN that regulates the rhythmic expression of the core clock genes through the feedback loop. At the output level, the SCN connects with the pineal gland and the peripheral tissues with the help of neuroendocrine mediators. Disruption of circadian clock functions is detrimental to health. Shift work, night work, chronic or acute jet lag, and light-at-night have adverse effects on circadian functions. Misalignment of circadian rhythm alters the expression of core clock genes, leading to deregulation of cellular activity and metabolic functions. Circadian rhythm dysfunction causes many pathologic conditions, including sleep disorders, cardiovascular problems, metabolic dysfunction, infertility, poor physical performance, as well as cancer. The present work has reviewed the relationship between circadian clock dysfunction and impaired physiological activities.
All living organisms exhibit circadian rhythms. Humans show circadian rhythm of the different physiological functions such as sleep-wake cycle, core body temperature, feeding behavior, metabolic activity, heart rate variability, hormone secretion, and others. The hypothalamic suprachiasmatic nucleus (SCN) acts as a primary circadian pacemaker. Peripheral tissues have an endogenous circadian clock; however, SCN synchronizes the circadian activity of the peripheral clocks. The retinohypothalamic tract (RHT) from retinal ganglionic cells carries the photic signal into the SCN that regulates the rhythmic expression of the core clock genes through the feedback loop. At the output level, the SCN connects with the pineal gland and the peripheral tissues with the help of neuroendocrine mediators. Disruption of circadian clock functions is detrimental to health. Shift work, night work, chronic or acute jet lag, and light-at-night have adverse effects on circadian functions. Misalignment of circadian rhythm alters the expression of core clock genes, leading to deregulation of cellular activity and metabolic functions. Circadian rhythm dysfunction causes many pathologic conditions, including sleep disorders, cardiovascular problems, metabolic dysfunction, infertility, poor physical performance, as well as cancer. The present work has reviewed the relationship between circadian clock dysfunction and impaired physiological activities.
DOI: https://doi.org/10.37349/en.2022.00002
This article belongs to the special issue Circadian Rhythm and Melatonin
Neuregulins (NRGs) and their cognate ErbB receptors (ErbB2–ErbB4) constitute a vast group of proteins encoded by six different genes (NRG1–6) and many isoforms with critical roles in the development and functioning of the nervous system. NRGs are known to regulate important processes in the nervous system like neural development, neuronal differentiation, neurite outgrowth, and specification. These factors are involved in the regulation of neurotransmission pathways and the modulation of several forms of synaptic plasticity. Due to NRGs’ role in synaptic plasticity, defects in their normal functioning are translated into altered signaling networks, which have been linked to susceptibility to developing psychiatric disorders like schizophrenia (SZ), autism, depression, and bipolar disorders. Additionally, deviation of the NRG normal functioning is involved in neurological diseases like Alzheimer’s and Parkinson’s disease. Contrastingly, NRG/ErbB signaling is also involved in the recovery after traumatic brain injuries (e.g., ischemic stroke). The NRG/ErbB signaling complex is highly unusual because the ligands (mainly NRG1–NRG3, with their multiple isoforms) and receptors (ErbB2–ErbB4) can orchestrate vast signaling complexes, with a wide reach within the processes that govern the development and appropriate function of the nervous system. This may explain why NRGs and ErbB receptor genes have been linked to complex brain disorders, like SZ. This review, are discussed important aspects of NRG and their relevance for nervous system functioning, including 1) subcellular localization, 2) signaling pathways involved in neuronal functions, 3) effect on neurite development and synapse formation, 4) modulation of some mechanisms of synaptic plasticity [long-term potentiation (LTP), depotentiation, long-term depression (LTD)] and 5) roles of NRGs in some neurological diseases. This review intends to present a summary of the main findings about this family of proteins, which might position them as one of the master regulators of brain functioning.
Neuregulins (NRGs) and their cognate ErbB receptors (ErbB2–ErbB4) constitute a vast group of proteins encoded by six different genes (NRG1–6) and many isoforms with critical roles in the development and functioning of the nervous system. NRGs are known to regulate important processes in the nervous system like neural development, neuronal differentiation, neurite outgrowth, and specification. These factors are involved in the regulation of neurotransmission pathways and the modulation of several forms of synaptic plasticity. Due to NRGs’ role in synaptic plasticity, defects in their normal functioning are translated into altered signaling networks, which have been linked to susceptibility to developing psychiatric disorders like schizophrenia (SZ), autism, depression, and bipolar disorders. Additionally, deviation of the NRG normal functioning is involved in neurological diseases like Alzheimer’s and Parkinson’s disease. Contrastingly, NRG/ErbB signaling is also involved in the recovery after traumatic brain injuries (e.g., ischemic stroke). The NRG/ErbB signaling complex is highly unusual because the ligands (mainly NRG1–NRG3, with their multiple isoforms) and receptors (ErbB2–ErbB4) can orchestrate vast signaling complexes, with a wide reach within the processes that govern the development and appropriate function of the nervous system. This may explain why NRGs and ErbB receptor genes have been linked to complex brain disorders, like SZ. This review, are discussed important aspects of NRG and their relevance for nervous system functioning, including 1) subcellular localization, 2) signaling pathways involved in neuronal functions, 3) effect on neurite development and synapse formation, 4) modulation of some mechanisms of synaptic plasticity [long-term potentiation (LTP), depotentiation, long-term depression (LTD)] and 5) roles of NRGs in some neurological diseases. This review intends to present a summary of the main findings about this family of proteins, which might position them as one of the master regulators of brain functioning.
DOI: https://doi.org/10.37349/en.2022.00003
This brief statement describes some recent achievements of neuropathological research, with the focus on Alzheimer’s and other age-related diseases, neurodegenerative disorders (tauopathies, synucleinopathies), multimorbidity of the aged brain, multiple sclerosis (MS), and other neuroinflammatory disorders, including central nervous system involvement by coronavirus disease 2019 (COVID-19), as well as new developments in neurovascular diseases, neurooncology, and myopathies. Although neuropathology, using modern technologies, such as cryo-electron microscopy, proteomic and experimental methods, has helped to increase diagnostic accuracy and provided insight into the pathogenesis of many neurological disorders, future studies in co-operation with clinical and other neurosciences should overcome the challenges of disease-influencing therapeutic approaches.
This brief statement describes some recent achievements of neuropathological research, with the focus on Alzheimer’s and other age-related diseases, neurodegenerative disorders (tauopathies, synucleinopathies), multimorbidity of the aged brain, multiple sclerosis (MS), and other neuroinflammatory disorders, including central nervous system involvement by coronavirus disease 2019 (COVID-19), as well as new developments in neurovascular diseases, neurooncology, and myopathies. Although neuropathology, using modern technologies, such as cryo-electron microscopy, proteomic and experimental methods, has helped to increase diagnostic accuracy and provided insight into the pathogenesis of many neurological disorders, future studies in co-operation with clinical and other neurosciences should overcome the challenges of disease-influencing therapeutic approaches.
DOI: https://doi.org/10.37349/en.2022.00004
Ischemic stroke is a highly prevalent condition that frequently results in life-long disability and death. Considerable efforts have been made to establish treatments that prevent secondary ischemic damage and promote stroke recovery. Until now, the recanalization of occluded blood vessels via thrombolysis and thrombectomy, although highly potent, remains the only treatment in humans that enhances stroke outcome. Small extracellular vesicles are non-replicating, nano-sized (70–150 nm) lipid bilayer-enclosed vesicles, which have shown remarkable biological activities in various physiological and pathophysiological contexts. When administered post-stroke, mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) induce neuroprotection, promote brain remodeling and plasticity, and enhance neurological recovery in rodents and non-human primates via mechanisms that involve immunomodulation and anti-inflammation. In this review, experimental studies on the therapeutic actions of MSC-EVs in animal stroke models are summarized and perspectives for clinical translation are outlined.
Ischemic stroke is a highly prevalent condition that frequently results in life-long disability and death. Considerable efforts have been made to establish treatments that prevent secondary ischemic damage and promote stroke recovery. Until now, the recanalization of occluded blood vessels via thrombolysis and thrombectomy, although highly potent, remains the only treatment in humans that enhances stroke outcome. Small extracellular vesicles are non-replicating, nano-sized (70–150 nm) lipid bilayer-enclosed vesicles, which have shown remarkable biological activities in various physiological and pathophysiological contexts. When administered post-stroke, mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) induce neuroprotection, promote brain remodeling and plasticity, and enhance neurological recovery in rodents and non-human primates via mechanisms that involve immunomodulation and anti-inflammation. In this review, experimental studies on the therapeutic actions of MSC-EVs in animal stroke models are summarized and perspectives for clinical translation are outlined.
DOI: https://doi.org/10.37349/en.2022.00005
Neuroinflammation plays a key role in the pathogenesis of post-cardiac arrest (CA) brain injury. Innate immune cells sense a variety of danger signals through pattern-recognition receptors and evoke rapidly after ischemic challenge, triggering inflammatory responses and amplifying brain damage. A programmed cell death (PCD) pathway is activated after ischemic and/or inflammatory stimuli, leading to the elimination of the damaged cells. However, PCD also regulates inflammatory responses flexibly. The present review aimed to summarize the mechanisms of inflammatory responses, including the biology of immune cells, the innate immune recognition that initiates the inflammation, and the immunomodulatory effects of PCD following CA. Promising therapeutic approaches of targeting inflammatory responses to alleviate brain injury and improve neurological outcomes after CA are also reviewed.
Neuroinflammation plays a key role in the pathogenesis of post-cardiac arrest (CA) brain injury. Innate immune cells sense a variety of danger signals through pattern-recognition receptors and evoke rapidly after ischemic challenge, triggering inflammatory responses and amplifying brain damage. A programmed cell death (PCD) pathway is activated after ischemic and/or inflammatory stimuli, leading to the elimination of the damaged cells. However, PCD also regulates inflammatory responses flexibly. The present review aimed to summarize the mechanisms of inflammatory responses, including the biology of immune cells, the innate immune recognition that initiates the inflammation, and the immunomodulatory effects of PCD following CA. Promising therapeutic approaches of targeting inflammatory responses to alleviate brain injury and improve neurological outcomes after CA are also reviewed.
DOI: https://doi.org/10.37349/en.2023.00014
Brain metastasis is the most prevalent neurologic problem of systemic cancer and it can increase the mortality rate in patients with cancer. It occurs more in patients with lung cancer, breast cancer, and melanoma. There are several molecular mechanisms in cancer cell progression, invasion, and location in new places during brain metastasis. Significant interactions between cancer cells, the brain microenvironment, and the blood-brain barrier (BBB) play a major role in brain metastasis. This study will focus on molecular mechanisms that contribute to cancer metastasis into the brain and finding new treatments with molecular research. Treatment strategies in patients with brain metastasis include surgical resection, radiotherapy, and chemotherapy; however, the penetration of chemotherapy drugs beyond the BBB is limited. Studying molecular, cellular, and physical mechanisms in brain metastasis helps to improve new strategies in drug delivery across the BBB. There are significant impacts of ion channels in brain metastasis and cancer treatment failure. Targeting molecular mechanisms and ion channels in brain metastasis led to increasing the better response in these patients. In this way, nano-drugs have caused a revolution in effective targeting and drug delivery in cancer treatment. This review describes the advances to facilitate the penetration of drugs in the BBB by using nano-drugs especially those that are targeting ion channels.
Brain metastasis is the most prevalent neurologic problem of systemic cancer and it can increase the mortality rate in patients with cancer. It occurs more in patients with lung cancer, breast cancer, and melanoma. There are several molecular mechanisms in cancer cell progression, invasion, and location in new places during brain metastasis. Significant interactions between cancer cells, the brain microenvironment, and the blood-brain barrier (BBB) play a major role in brain metastasis. This study will focus on molecular mechanisms that contribute to cancer metastasis into the brain and finding new treatments with molecular research. Treatment strategies in patients with brain metastasis include surgical resection, radiotherapy, and chemotherapy; however, the penetration of chemotherapy drugs beyond the BBB is limited. Studying molecular, cellular, and physical mechanisms in brain metastasis helps to improve new strategies in drug delivery across the BBB. There are significant impacts of ion channels in brain metastasis and cancer treatment failure. Targeting molecular mechanisms and ion channels in brain metastasis led to increasing the better response in these patients. In this way, nano-drugs have caused a revolution in effective targeting and drug delivery in cancer treatment. This review describes the advances to facilitate the penetration of drugs in the BBB by using nano-drugs especially those that are targeting ion channels.
DOI: https://doi.org/10.37349/en.2024.00040
This article belongs to the special issue Current Approaches to Malignant Tumors of the Nervous System
Aim:
The aim of this paper is to discuss the main features and first outcomes of a therapeutic platform proposed to implement a public health therapeutic service for patients suffering refractory epilepsy.
Methods:
The proposal is a three-layer system composed by a new portable therapy device and two software applications. The therapy is transcutaneous electrical vagus nerve stimulation, known as tVNS. The primary layer is composed of tVNS devices, configured for each patient according to the instructions provided by the specialists. The middle layer is named “hospital data collector” (HDC), its main tasks are the patient enrollment, the device setup, and the database maintenance to store therapeutic parameters and session events together with the information cited previously. Each hospital center runs a HDC that is connected to a cloud application named “system cloud application (SCA)” which concentrates all the data supplied by the HDCs. Artificial intelligence methods are integrated in the SCA to predict the treatment effectiveness for every new patient based on the accumulated knowledge from the enrolled previously.
Results:
A version of the proposed system is running at the Institute of Neurology and Neurosurgery. The sensitivity of the therapeutic device with the proposed treatment protocol reaches 83.33% in the 18-patient pilot trial carried out.
Conclusions:
The proposed approach seems a useful therapeutic tool based on the pilot trial outcomes. The developed device is comfortable and suitable for the intended use. The proposed system has created the essential conditions to feed and grow a knowledge, a basic element to predict the treatment effectiveness for each new patient. It is a promising option for a refractory epilepsy therapy service.
Aim:
The aim of this paper is to discuss the main features and first outcomes of a therapeutic platform proposed to implement a public health therapeutic service for patients suffering refractory epilepsy.
Methods:
The proposal is a three-layer system composed by a new portable therapy device and two software applications. The therapy is transcutaneous electrical vagus nerve stimulation, known as tVNS. The primary layer is composed of tVNS devices, configured for each patient according to the instructions provided by the specialists. The middle layer is named “hospital data collector” (HDC), its main tasks are the patient enrollment, the device setup, and the database maintenance to store therapeutic parameters and session events together with the information cited previously. Each hospital center runs a HDC that is connected to a cloud application named “system cloud application (SCA)” which concentrates all the data supplied by the HDCs. Artificial intelligence methods are integrated in the SCA to predict the treatment effectiveness for every new patient based on the accumulated knowledge from the enrolled previously.
Results:
A version of the proposed system is running at the Institute of Neurology and Neurosurgery. The sensitivity of the therapeutic device with the proposed treatment protocol reaches 83.33% in the 18-patient pilot trial carried out.
Conclusions:
The proposed approach seems a useful therapeutic tool based on the pilot trial outcomes. The developed device is comfortable and suitable for the intended use. The proposed system has created the essential conditions to feed and grow a knowledge, a basic element to predict the treatment effectiveness for each new patient. It is a promising option for a refractory epilepsy therapy service.
DOI: https://doi.org/10.37349/en.2024.00041
This article belongs to the special issue Epilepsy
Major depressive disorder (MDD) is a common mental disorder associated with significant suffering and disability. Recent evidence has highlighted the role of the gut-brain axis in the pathogenesis of MDD. Enteric glial cells are a structurally and functionally diverse population that plays a key role in regulating enteric nervous function and maintaining intestinal mucosal integrity. These cells may be implicated in the origin of several digestive and extra-digestive disorders, known as enteric neuro-gliopathies (ENG). This paper reviews the evidence that MDD may also belong to the category of ENG. Animal models suggest that environmental adversity can lead to enteric glial dysfunction and depressive-like behaviors. Conditions that are highly comorbid with MDD, both intestinal and extra-intestinal, have been linked to enteric glial alterations. Peripheral blood markers linked to glial integrity and function are altered in patients with MDD, and certain treatments for MDD may have beneficial effects on enteric glial functioning. Though much of this evidence is indirect and provisional, it suggests that MDD may belong to the group of ENG. Further investigation of enteric glial functioning in MDD may yield valuable insights into the pathophysiology and treatment of this disorder.
Major depressive disorder (MDD) is a common mental disorder associated with significant suffering and disability. Recent evidence has highlighted the role of the gut-brain axis in the pathogenesis of MDD. Enteric glial cells are a structurally and functionally diverse population that plays a key role in regulating enteric nervous function and maintaining intestinal mucosal integrity. These cells may be implicated in the origin of several digestive and extra-digestive disorders, known as enteric neuro-gliopathies (ENG). This paper reviews the evidence that MDD may also belong to the category of ENG. Animal models suggest that environmental adversity can lead to enteric glial dysfunction and depressive-like behaviors. Conditions that are highly comorbid with MDD, both intestinal and extra-intestinal, have been linked to enteric glial alterations. Peripheral blood markers linked to glial integrity and function are altered in patients with MDD, and certain treatments for MDD may have beneficial effects on enteric glial functioning. Though much of this evidence is indirect and provisional, it suggests that MDD may belong to the group of ENG. Further investigation of enteric glial functioning in MDD may yield valuable insights into the pathophysiology and treatment of this disorder.
DOI: https://doi.org/10.37349/en.2024.00042
This article belongs to the special issue Enteric Neuro-Gliopathies: Ready for Prime Time?
Epileptic seizures are prevalent in people with brain vascular abnormalities like arteriovenous malformations (AVMs) and cavernous malformations, greatly affecting their quality of life. The connection between intracranial vascular abnormalities and epilepsy is still under debate. Therefore, investigating epilepsy in individuals with AVMs is a crucial and current research area. This review presents a comprehensive examination of recent developments in epilepsy among individuals with brain AVMs. The authors conducted a detailed analysis of the natural progression, epidemiology, diagnostic methods, therapeutic approaches, and post-treatment outcomes for individuals with epilepsy associated with AVMs.
Epileptic seizures are prevalent in people with brain vascular abnormalities like arteriovenous malformations (AVMs) and cavernous malformations, greatly affecting their quality of life. The connection between intracranial vascular abnormalities and epilepsy is still under debate. Therefore, investigating epilepsy in individuals with AVMs is a crucial and current research area. This review presents a comprehensive examination of recent developments in epilepsy among individuals with brain AVMs. The authors conducted a detailed analysis of the natural progression, epidemiology, diagnostic methods, therapeutic approaches, and post-treatment outcomes for individuals with epilepsy associated with AVMs.
DOI: https://doi.org/10.37349/en.2024.00043
This article belongs to the special issue Epilepsy
New onset refractory status epilepticus (NORSE) is an etiologically heterogeneous condition that is associated with high morbidity and mortality. NORSE is often refractory to medical management prompting a workup for epilepsy surgery. Because NORSE remains etiologically elusive in most cases, surgical evaluations are challenging, especially when the epileptogenic zone (EZ) is not easy to lateralize as can be seen in frontal lobe seizures. Lateralizing a frontal lobe EZ may be challenging due to bilateral synchrony from commissural connections through the corpus callosum and low spatiotemporal resolution of the scalp electroencephalography (EEG). We report a pediatric patient with NORSE presenting with focal impaired awareness seizures clustering into super refractory status epilepticus (SRSE). She required surgical intervention for the treatment of her seizures after failing therapeutic doses of antiseizure medications, anesthetic drips, immunomodulation with methylprednisolone, intravenous immunoglobulin and anakinra, and the ketogenic diet. Despite her semiology being focal, the seizures were not well lateralized on scalp EEG and during phase 2 stereo-EEG (sEEG). Anterior magnetic resonance-guided laser interstitial thermal therapy corpus callosotomy (MRgLITT CC) was performed in a multistage surgical approach to successfully lateralize the EZ with a left-lateralized ictal pattern seen after reimplantation of sEEG electrodes. Our case suggests that minimally invasive MRgLITT CC can be successfully used to lateralize an EZ in frontal lobe epilepsy and that epilepsy surgery should be considered in patients with NORSE with SRSE. We also demonstrate that laser interstitial thermal therapy (LITT), while not always resulting in seizure freedom, can sufficiently disrupt a network to abort status epilepticus and lead to seizure improvements.
New onset refractory status epilepticus (NORSE) is an etiologically heterogeneous condition that is associated with high morbidity and mortality. NORSE is often refractory to medical management prompting a workup for epilepsy surgery. Because NORSE remains etiologically elusive in most cases, surgical evaluations are challenging, especially when the epileptogenic zone (EZ) is not easy to lateralize as can be seen in frontal lobe seizures. Lateralizing a frontal lobe EZ may be challenging due to bilateral synchrony from commissural connections through the corpus callosum and low spatiotemporal resolution of the scalp electroencephalography (EEG). We report a pediatric patient with NORSE presenting with focal impaired awareness seizures clustering into super refractory status epilepticus (SRSE). She required surgical intervention for the treatment of her seizures after failing therapeutic doses of antiseizure medications, anesthetic drips, immunomodulation with methylprednisolone, intravenous immunoglobulin and anakinra, and the ketogenic diet. Despite her semiology being focal, the seizures were not well lateralized on scalp EEG and during phase 2 stereo-EEG (sEEG). Anterior magnetic resonance-guided laser interstitial thermal therapy corpus callosotomy (MRgLITT CC) was performed in a multistage surgical approach to successfully lateralize the EZ with a left-lateralized ictal pattern seen after reimplantation of sEEG electrodes. Our case suggests that minimally invasive MRgLITT CC can be successfully used to lateralize an EZ in frontal lobe epilepsy and that epilepsy surgery should be considered in patients with NORSE with SRSE. We also demonstrate that laser interstitial thermal therapy (LITT), while not always resulting in seizure freedom, can sufficiently disrupt a network to abort status epilepticus and lead to seizure improvements.
DOI: https://doi.org/10.37349/en.2024.00044
This article belongs to the special issue Epilepsy
Aim:
The aim of this work was to study the effects of extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) on inflammation-impaired cognitive functions and the brain of mice.
Methods:
Young mice (~3-month-old) and aged mice (~18-month-old) were injected with bacterial lipopolysaccharide (LPS) and obtained intravenously donor 106 human umbilical cord MSCs, EVs isolated from a similar amount of MSCs or conditioned medium (CM) of MSCs. Subsequently, the mice were examined in behavioral tests and the mouse brains were analyzed for the levels of pro-inflammatory cytokines, α7 nicotinic acetylcholine receptors (α7 nAChRs) and amyloid beta 1-42 (Aβ1-42).
Results:
EVs prevented LPS-induced memory impairment in mice, whereas CM provided a weaker and temporal effect. Both EVs and MSCs injected once after regular injections of LPS stably improved memory of young mice. In contrast, both cells and EVs provided only transient effect in aged mice injected with LPS. The brains of aged LPS-treated mice contained elevated amounts of IL-1β and IL-6; both MSCs and EVs decreased them significantly. The brains of non-treated aged mice contained decreased levels of α7 nAChRs and increased levels of Aβ1-42 and α7-bound Aβ1-42 compared to the brains of young mice. LPS treatment decreased α7 nAChRs in both young and aged mice, while both MSCs and EVs restored them up to the control level. In young mice, LPS treatment increased the level of Aβ1-42 and α7-bound Aβ1-42, whereas MSCs and EVs decreased it. In contrast, neither LPS nor MSCs/EVs influenced the elevated level of Aβ1-42 but increased α7-bound Aβ1-42 in the brains of aged mice.
Conclusions:
Regenerative potential of MSCs and MSC-derived EVs is sufficient to support cognitive functions of LPS-treated young mice but is quite poor for aged animals, possibly, due to decreased levels of α7 nAChRs and accumulated Aβ1-42 in their brains.
Aim:
The aim of this work was to study the effects of extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) on inflammation-impaired cognitive functions and the brain of mice.
Methods:
Young mice (~3-month-old) and aged mice (~18-month-old) were injected with bacterial lipopolysaccharide (LPS) and obtained intravenously donor 106 human umbilical cord MSCs, EVs isolated from a similar amount of MSCs or conditioned medium (CM) of MSCs. Subsequently, the mice were examined in behavioral tests and the mouse brains were analyzed for the levels of pro-inflammatory cytokines, α7 nicotinic acetylcholine receptors (α7 nAChRs) and amyloid beta 1-42 (Aβ1-42).
Results:
EVs prevented LPS-induced memory impairment in mice, whereas CM provided a weaker and temporal effect. Both EVs and MSCs injected once after regular injections of LPS stably improved memory of young mice. In contrast, both cells and EVs provided only transient effect in aged mice injected with LPS. The brains of aged LPS-treated mice contained elevated amounts of IL-1β and IL-6; both MSCs and EVs decreased them significantly. The brains of non-treated aged mice contained decreased levels of α7 nAChRs and increased levels of Aβ1-42 and α7-bound Aβ1-42 compared to the brains of young mice. LPS treatment decreased α7 nAChRs in both young and aged mice, while both MSCs and EVs restored them up to the control level. In young mice, LPS treatment increased the level of Aβ1-42 and α7-bound Aβ1-42, whereas MSCs and EVs decreased it. In contrast, neither LPS nor MSCs/EVs influenced the elevated level of Aβ1-42 but increased α7-bound Aβ1-42 in the brains of aged mice.
Conclusions:
Regenerative potential of MSCs and MSC-derived EVs is sufficient to support cognitive functions of LPS-treated young mice but is quite poor for aged animals, possibly, due to decreased levels of α7 nAChRs and accumulated Aβ1-42 in their brains.
DOI: https://doi.org/10.37349/en.2024.00045
