Subarachnoid hemorrhage (SAH) has deleterious outcomes for patients, and during the hospital stay, patients are susceptible to vasospasm and delayed cerebral ischemia. Coronavirus disease 2019 (COVID-19) has been shown to worsen hypertension through angiotensin-converting enzyme 2 (ACE2) activity, therefore, predisposing to aneurysm rupture. The classic renin-angiotensin pathway activation also predisposes to vasospasm and subsequent delayed cerebral ischemia. Matrix metalloproteinase 9 upregulation can lead to an inflammatory surge, which worsens outcomes for patients. SAH patients with COVID-19 are more susceptible to ventilator-associated pneumonia, reversible cerebral vasoconstriction syndrome, and respiratory distress. Emerging treatments are warranted to target key components of the anti-inflammatory cascade. The aim of this review is to explore how the COVID-19 virus and the intensive care unit (ICU) treatment of severe COVID can contribute to SAH.

Altered immunity may have destructive consequences for the integrated central nervous system. This immune response often affects progressive neurodegenerative diseases such as Parkinson’s disease and/or psychiatric disorders such as schizophrenia. In particular, schizophrenia pathogenesis may be mediated by multiple neuro-immune interaction pathways. Gut microbiota might affect the brain and/or immune function. Significant machineries of immunity are commonly affected by the commensal gut microbiota. Therefore, schizophrenia may be connected with the gut-immune system. In addition, the brain and immune systems cooperate on multiple levels. The brain could save several pieces of information about specific inflammation in a body. This immunological memory named “engrams”, also called memory traces, could restore the initial disease state, which may help to explain key features of schizophrenia. Based on this concept, therapeutic strategies for schizophrenia could be the modification of the gut microbiota. Probiotics and/or fecal microbiota transplantation are now emerging as the most promising treatments for the modification. More consideration of the roles of gut microbiota will conduct the further development of immune-based therapeutics for the prevention and/or treatments of psychiatric disorders.

Several studies investigated the side effect of adjuvant cancer treatments, and different types of preventive techniques or treatments have been assessed. Chemotherapy-induced peripheral neuropathy (CIPN) is the most common neurological side effect. Exercise training has been widely studied as an adjuvant therapy to prevent CIPN and improve post-chemotherapy functional outcome and quality of life (QoL). This narrative review aims to summarize the data obtained from the latest studies about physical activity (PA) for the prevention and treatment of CIPN and associated QoL measures. Literature research was conducted to obtain studies including PA interventions for patients with CIPN. Ten studies met inclusion criteria and were therefore summarized and discussed, focusing on exercise type and functional outcome. It seems clear that, regardless of the type of exercise, PA plays a positive role in the treatment of CIPN, providing a significant symptom improvement. There has been no standardization of type, quantity, and intensity of PA administered to the subjects in the various studies probably due to a physiological difference between samples, grade of neuropathy, and difference among therapies.

The glymphatic system, first described in 2012, is a brain-wide perivascular network that plays an important role in promoting interstitial metabolic waste removal from the brain. Glymphatic pathway function has been reported to be dramatically diminished in the aging brain. Furthermore, glymphatic system dysfunction has been linked to a spectrum of neurodegenerative diseases including Alzheimer’s disease (AD). This waste clearance pathway of the brain is most active during sleep and is largely disengaged during wakefulness. While norepinephrine (NE) is responsible for suppressing the glymphatic function, electroencephalographic slow-wave (delta) activity has a facilitating effect. An intriguing question is whether these regulators of glymphatic activity can be modulated by meditation-based approaches and whether such approaches have the ability to increase glymphatic function in the awake brain. The present article hypothesizes that meditation-based approaches, such as immersive sound meditation, may have the potential to enhance glymphatic pathway transport and solute clearance by reducing NE and increasing slow-wave activity. If confirmed, meditation could be an attractive approach to promoting healthy brain aging and to preventing neurodegenerative conditions like AD.

The glymphatic system, or glial-lymphatic system, is a waste clearance system composed of perivascular channels formed by astrocytes that mediate the clearance of proteins and metabolites from the brain. These channels facilitate the movement of cerebrospinal fluid throughout brain parenchyma and are critical for homeostasis. Disruption of the glymphatic system leads to an accumulation of these waste products as well as increased interstitial fluid in the brain. These phenomena are also seen during and after subarachnoid hemorrhages (SAH), contributing to the brain damage seen after rupture of a major blood vessel. Herein this review provides an overview of the glymphatic system, its disruption during SAH, and its function in recovery following SAH. The review also outlines drugs which target the glymphatic system and may have therapeutic applications following SAH.

Stroke is one of the most common causes of disability and exerts a high burden of direct and indirect costs. Stroke may cause spasticity, which limits patients’ abilities and affects their activities of daily living, decreasing their quality of life. Conventional treatments are based on physical therapy, anti-spasticity medication, and botulinum toxin type A (BTX-A). However, recently, non-pharmacological approaches have been used, such as dry needling (DN) of myofascial trigger points. BTX-A and DN are two treatments that aim to decrease spasticity in patients with stroke, but their mode of action, application, and costs differ. Thus, there is a need to determine the comparative economics of post-stroke spasticity treatments. For this purpose, a search for all types of cost-effectiveness studies (randomized controlled trials, matched controls, and cohorts) and models of epidemiological data was performed. Studies were selected if they included economic outcomes in stroke patients treated with BTX-A or DN. As a result, 7 studies of BTX-A and 2 of DN were selected. Similarities were found in the outcomes used to assess the effectiveness of both treatments in most studies, with modifications of the Ashworth Scale [Modified Ashworth Scale (MAS)/Modified Modified Ashworth Scale (MMAS)] and quality-adjusted life year (QALY) being the main indicators of effectiveness. However, both the duration of the studies and the evaluation of costs were highly heterogeneous, making comparison difficult. In conclusion, both BTX-A and DN are cost-effective to treat spasticity in patients with stroke, but there is a need for comparative studies to make direct comparisons of cost-effectiveness with the most frequently used outcomes such as the MMAS and QALYs.

Autism spectrum disorder (ASD) is a class of neurodevelopmental disorders (NDD) characterized by deficits in three domains: impairments in social interactions, language, and communication, and increased stereotyped restrictive/repetitive behaviors and interests. The exact etiology of ASD remains unknown. Genetics, gestational exposure to inflammation, and environmental stressors, which combine to affect mitochondrial dysfunction and metabolism, are implicated yet poorly understood contributors and incompletely delineated pathways toward the relative risk of ASD. Many studies have shown a clear male bias in the incidence of ASD and other NDD. In other words, being male is a significant yet poorly understood risk factor for the development of NDD. This review discusses the link between these factors by looking at the current body of evidence. Understanding the link between the multiplicity of hits—from genes to environmental stressors and possible sexual determinants, contributing to autism susceptibility is critical to developing targeted interventions to mitigate these risks.

Delayed cerebral ischemia after subarachnoid hemorrhage is one of the most important causes of mortality and poor functional outcome in patients. Initially, the etiology and treatment of delayed cerebral ischemia focused primarily on cerebral vasospasm. However, recent studies have detected that depolarization, microcirculation, and autoregulation disorder, which spreads together with cerebral vasospasm, also play a role in the etiology. The main treatment strategies in the prevention and treatment of delayed cerebral ischemia are the regulation of blood pressure and the use of calcium channel blockers, especially nimodipine. The main step in the early diagnosis and treatment of the disease is to monitor the neurological clinical status. In addition to transcranial Doppler ultrasonography, computed tomography, or magnetic resonance imaging angiography, continuous electroencephalography and invasive brain multimodal examination may be required in the follow-up period of the disease. In addition to blood pressure regulation, optimization of cardiac output, endovascular interventions, angioplasty, and/or intra-arterial vasodilator infusion are other treatment methods. This review aimed to evaluate delayed cerebral ischemia, one of the most important complications of subarachnoid hemorrhage, in the light of current literature.

The global prevalence of intracranial aneurysms (IA) ranges from 5–10%, with a demographic variation. Large and giant aneurysms typically involve cavernous and paraclinoid segments of the internal carotid artery (ICA), and represent 5% of IA. Typically, these lesions involve segments of the ICA, especially the cavernous and paraclinoid segments. The remaining cases affect the vertebrobasilar region, middle cerebral artery (MCA), and anterior cerebral artery (ACA). From the morphological point of view, they are divided into saccular and fusiform. In cases of rupture, the subarachnoid hemorrhage (SAH) is the most common presentation followed by intracerebral hemorrhage (ICH), or both. Other manifestations can occur as occlusion of perforating vessels, embolic events, seizures, and mass effects. The management of unruptured intracranial aneurysms (UIA) is controversial, and the aim of treatment is to exclude the lesions and preserve neurological function. Endovascular techniques for the treatment of paraclinoid aneurysms, in particular, ICA reconstruction using flow-diverting stents, have become a valid option. However, surgery or endovascular treatment has a number of limitations and the choice of treatment is individual in each case. This type of lesion has an extremely poor natural history, and treatment is a challenge regardless of the technique used.

The report described a clinical case of a 55-year-old female, with a personal history of hypertension, hyperthyroidism, and depressive syndrome. The patient started complaints of moderate-intensity right frontal headache, progressively worsening with two months of evolution. She also reported blurred vision and diplopia. Brain computed tomography (CT) documented a partially calcified sellar and parasellar lesion. Subsequently, magnetic resonance imaging (MRI)/MRI angiographies were performed and showed a saccular aneurysm of the right ICA, cavernous segment. The patient underwent a diagnostic and therapeutic angiography with stent placement. Clinical and imaging improvements were documented by angiography and MRI angiography with progressive reduction of the aneurysm during the period of follow-up.

The autism spectrum disorder (ASD) comprises a series of neurological diseases that share serious alterations of the development of the central nervous system. The degree of disability may vary so that Asperger’s may have a relatively normal life and get positions of responsibility in corporations and even in Governments, whereas other ASD sufferers are fully dependent on caregivers and have serious cognitive deficits. Although the first cases of autism were detected by looking at failures in metabolism, e.g., phenylketonuria, to later identify the faulty gene, today the trend is the opposite, first obtaining the exome and minimizing the look for altered parameters in blood, urine, etc. Cholesterol is key for neural development as it is not able to cross the blood brain barrier. Therefore, any gene or environmental factor that affects cholesterol synthesis will impact early developmental stages eventually leading to a disease within the autism spectrum and/or schizophrenia. This review provides data of the relevance of cholesterol dyshomeostasis in autism spectrum disorders. Determining biochemical parameters in body fluids should help to provide new therapeutic approaches in some cases of autism.

Early in the course of infection, human immunodeficiency virus (HIV) is able to enter the central nervous system where it stablishes a permanent reservoir. Current antiretroviral therapies do not efficiently cross the blood-brain barrier and therefore do not reach the HIV located in the central nervous system. Consequently, HIV infection can often be associated with neurocognitive impairment and HIV-associated dementia. The purpose of this review is to brief the reader into the world of neurological complications arising from HIV infection. Mechanisms by which HIV directly or indirectly impairs the central nervous system are discussed, as well as other factors influencing or contributing to the impairment, and the animal models currently used to perform research on the topic.

The pathogenic basis behind some of the most prevalent neurodegenerative diseases in advanced societies, known as proteinopathies, deals with alterations in protein homeostasis. Despite the broad diversity of clinical symptoms, they share a remarkably common feature that is the serious neuronal loss in several disease-specific brain regions due to the presence of toxic aggregations of misfolded proteins. So far, research efforts have been insufficient to decipher the exact molecular mechanisms that trigger the conformational change from a functional healthy protein to its pathological version. This is a sine qua non condition to progress in developing new approaches and treatments for these diseases for which there is no cure. Currently, it is well accepted that perturbations in gut microbiota composition negatively impact a wide range of brain processes via the gut-brain axis which increases host susceptibility to neurodegenerative disorders. In this context, modulate the microbial ecosystem colonizing the gastrointestinal tract may be a promising therapeutic approach in the management of proteinopathies. This review aims to provide an updated view of the role that gut microbiota poses in the pathogenesis of Parkinson’s disease, Alzheimer’s disease and Huntington’s disease, the most common neurodegenerative proteinopathies, and of the possibility of translating this knowledge into effective and safe clinical microbiota-based interventions, especially those designed to afford neuroprotection.

Since the identification and cloning of the cannabinoid receptor 2 (CB₂R), several studies focused on the characterization of its physiological and pathological role. Initially, CB₂R was considered as the peripheral cannabinoid receptor due to its detection in the rat spleen and leukocyte subpopulation in humans. Later, CB₂R was identified in different brain regions significantly modifying the landscape and pointing out its role in a wide variety of central physiological functions and pathological conditions. Additional research also detected the expression of CB₂R in neurons, microglia, and astroglia in different brain regions. Indeed, the findings collected to date support a significant function of CB₂R in anxiety, depression, schizophrenia, and additional neuropsychiatric disorders. This review gathers the most relevant literature regarding new advances about the role of CB₂R in a variety of neuropsychiatric conditions, with special emphasis on its potential as a new therapeutic target for the treatment of different psychiatric disorders.

Current evidence indicates that neurodegeneration of dopaminergic neurons of the substantia nigra associated to Parkinson’s disease is a consequence of a neuroinflammatory process in which microglial cells play a central role. The initial activation of microglial cells is triggered by pathogenic protein inclusions, which are mainly composed by α-synuclein. Importantly, these pathogenic forms of α-synuclein subsequently induce a T-cell-mediated autoimmune response to dopaminergic neurons. Depending on their functional phenotype, these autoreactive T-cells might shape the functional features of activated microglia. T-cells bearing pro-inflammatory phenotypes such as T-helper (Th)1 or Th17 promote a chronic inflammatory behaviour on microglia, whilst anti-inflammatory T-cells, such as regulatory T-cells (Treg) favour the acquisition of neuroprotective features by microglia. Thus, T-cells play a fundamental role in the development of neuroinflammation and neurodegeneration involved in Parkinson’s disease. This review summarizes the evidence indicating that not only CD4⁺ T-cells, but also CD8⁺ T-cells play an important role in the physiopathology of Parkinson’s disease. Next, this review analyses the different T-cell epitopes derived from the pathogenic forms of α-synuclein involved in the autoimmune response associated to Parkinson’s disease in animal models and humans. It also summarizes the requirement of specific alleles of major histocompatibility complexes (MHC) class I and class II necessaries for the presentation of CD8⁺ and CD4⁺ T-cell epitopes from the pathogenic forms of α-synuclein in both humans and animal models. Finally, this work summarizes and discusses a number of experimental immunotherapies that aim to strengthen the Treg response or to dampen the inflammatory T-cell response as a therapeutic approach in animal models of Parkinson’s disease.

Phosphoinositides are membrane phospholipids involved in a variety of cellular processes like growth, development, metabolism, and transport. This review focuses on the maintenance of cellular homeostasis of phosphatidylinositol 4,5-bisphosphate (PIP₂), and phosphatidylinositol 3,4,5-trisphosphate (PIP₃). The critical balance of these PIPs is crucial for regulation of neuronal form and function. The activity of PIP₂ and PIP₃ can be regulated through kinases, phosphatases, phospholipases and cholesterol microdomains. PIP₂ and PIP₃ carry out their functions either indirectly through their effectors activating integral signaling pathways, or through direct regulation of membrane channels, transporters, and cytoskeletal proteins. Any perturbations to the balance between PIP₂ and PIP₃ signaling result in neurodevelopmental and neurodegenerative disorders. This review will discuss the upstream modulators and downstream effectors of the PIP₂ and PIP₃ signaling, in the context of neuronal health and disease.

Spinal cord injury (SCI) induces several destructive events that develop immediately after the primary insult. These phenomena increase tissue damage; that is why, numerous therapeutic approaches are studied in order to neutralize these destructive mechanisms. In line with this, several studies indicate that after injury, neural tissue could be protected by an adaptive immune response directed against self-antigens. Immunization with neural-derived peptides (INDP) reduces secondary degeneration of neurons after spinal cord insult and promotes a significant motor recovery. The combination of antioxidants or other immunomodulatory peptides after SCI can improve the protective effect induced by INDP. INDP in acute SCI is a promising strategy, so further studies should be addressed to be able to formulate the best strategy.

Familial early-onset Alzheimer’s disease (AD) is more probable in individuals coming from mothers diagnosed with AD than from fathers diagnosed with AD. Studies in animal models have shown maternal imprinting due to the transmission to the embryo of altered material in the ovum. In the case of transgenic animals harboring a mutated form of the human amyloid precursor protein (APP), offspring from crosses with wild-type (WT) fathers and transgenic mothers display more abnormalities than offspring from crosses with transgenic fathers and WT mothers. Expression of the mutated APP in the ovum may lead to alterations that may be genetic and/or epigenetic in the nuclear and/or the mitochondrial DNA. These modifications that are transmitted to the new living beings affect more mitochondrial proteins and, therefore, the mitochondrial function may be affected in adulthood by trends present in the ovum.

Peroxisomes are actively involved in the metabolism of various lipids including fatty acids, ether phospholipids, bile acids as well as the processing of reactive oxygen and nitrogen species. Recent studies show that peroxisomes can regulate cholesterol homeostasis by mediating cholesterol transport from the lysosomes to the endoplasmic reticulum and towards primary cilium as well. Disruptions of peroxisome biogenesis or functions lead to peroxisomal disorders that usually involve neurological deficits. Peroxisomal dysfunction is also linked to several neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. In many peroxisomal disorders and neurodegenerative diseases, aberrant cholesterol accumulation is frequently encountered yet largely neglected. This review discusses the current understanding of the mechanisms by which peroxisomes facilitate cholesterol trafficking within the cell and the pathological conditions related to impaired cholesterol transport by peroxisomes, with the hope to inspire future development of the treatments for peroxisomal disorders and neurodegenerative diseases.

Niemann-Pick C disease is a rare neurodegenerative, lysosomal storage disease caused by accumulation of unesterified cholesterol. Diagnosis of the disease is often delayed due to its rarity, the heterogeneous presentation, and the early non-specific symptoms. The discovery of disease-specific biomarkers—cholestane-3β,5α,6β-triol (C-triol), trihydroxycholanic acid glycinate (TCG) and N-palmitoyl-O-phosphocholineserine [PPCS, initially referred to as lysosphingomyelin-509 (lysoSM-509)]—has led to development of non-invasive, blood-based diagnostics. Dissemination of these rapid, sensitive, and specific clinical assays has accelerated diagnosis. Moreover, the superior receiver operating characteristic of the TCG bile acid biomarker and its detection in dried blood spots has also facilitated development of a newborn screen for NPC, which is currently being piloted in New York state. The C-triol, TCG and PPCS biomarkers have also been proved useful for monitoring treatment response in peripheral tissues, but are uninformative with respect to treatment efficacy in the central nervous system (CNS). A major gap for the field is the lack of a validated, non-invasive biomarker to monitor the course of disease and CNS response to therapy.