Neurological Syndrome Research Articles

Humoral signatures of Caspr2-antibody spectrum disorder track with clinical phenotypes and outcomes.

Immunoglobulin (Ig) G4 auto-antibodies (Abs) against contactin-associated protein-like 2 (Caspr2), a transmembrane cell adhesion protein expressed in the central and peripheral nervous system, are found in patients with a broad spectrum of neurological symptoms. While the adoptive transfer of Caspr2-specific IgG induces brain pathology in susceptible rodents, the mechanisms by which Caspr2-Abs mediate neuronal dysfunction and translate into clinical syndromes are incompletely understood. We use a systems-level approach combined with high-dimensional characterization of Ab-associated immune features to deeply profile humoral biosignatures in patients with Caspr2-Ab-associated neurological syndromes. We identify two signatures strongly associated with two major clinical phenotypes, limbic encephalitis (LE) and predominant peripheral nerve hyperexcitability without LE (non-LE). Caspr2-IgG Fc-driven pro-inflammatory features, characterized by increased binding affinities for activating Fcγ receptors (FcγRs) and C1q, along with a higher prevalence of IgG1-class Abs, in addition to IgG4, are strongly associated with LE. Both the occurrence of Caspr2-specific IgG1 and higher serum levels of interleukin (IL)-6 and IL-15, along with increased concentrations of biomarkers reflecting neuronal damage and glial cell activation, are associated with poorer clinical outcomes at 1-year follow-up. The presence of IgG1 isotypes and Fc-mediated effector functions control the pathogenicity of Caspr2-specific Abs to induce LE. Biologics targeting FcR function might potentially restrain Caspr2-Ab-induced pathology and improve clinical outcomes. This study was funded by a German-French joint research program supported by the German Research Foundation (DFG) and the Agence Nationale de la Recherche (ANR) and by the Interdisciplinary Centre for Clinical Research (IZKF) Münster.

Paraneoplastic Syndromes of the Nervous System in Patients Suffering from SCLC. A Review of the Recent Literature

Background. Paraneoplastic Neurological Syndromes (PNS) constitute a heterogeneous cluster of disease manifestations related to various cancers. Small Cell Lung Cancer (SCLC) is strongly related to PNS. This narrative review conducted a survey in the available PubMed literature to highlight the appearance of PNSs in SCLC cases and discuss published research highlights on the subject so that general practitioners can be acquainted with the medical phenomenon present in SCLC patients. Method. A narrative review of the medical literature was conducted as documentary informative research in the PubMed medical database, combined with a survey of the online e-library Google Books. The key words used were: “Paraneoplastic Neurological Syndromes” and “Small Cell Lung Cancer”. Results. Paraneoplastic syndromes are related to the presence of a malignancy and are not secondary to treatment. Paradoxally, both a malignancy and its therapeutic approach may cause a series of PNSs. Paraneoplastic cerebellar degeneration, motor neuron disorders, peripheral neuropathies, hyponatremia, and syndromes such as myasthenic Lambert-Eaton, ectopic Cushing’s, Stiffman, and Opsoclonus-myoclonus syndrome may also appear in SCLC cases. Diagnosis follows specific criteria, and they are caused by tumor-directed antibodies known as onconeural antibodies. Immunosuppressants, intravenous immunoglobulins, plasma exchange, rituximab, cyclophosphamide, azathioprine, and tocilizumab could be considered as treatment agents. Conclusions. Most patients demonstrate poor PNS treatment results with common relapse. The time for beginning treatment of PNS is discussed. A multidisciplinary team is needed for potentially earlier diagnosis and PNS improvement, better prognosis, and increased overall survival and quality of life.

Blood-Brain Barrier Disruption in Neuroimmunological Disease.

The blood-brain barrier (BBB) acts as a structural and functional barrier for brain homeostasis. This review highlights the pathological contribution of BBB dysfunction to neuroimmunological diseases, including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), autoimmune encephalitis (AE), and paraneoplastic neurological syndrome (PNS). The transmigration of massive lymphocytes across the BBB caused by the activation of cell adhesion molecules is involved in the early phase of MS, and dysfunction of the cortical BBB is associated with the atrophy of gray matter in the late phase of MS. At the onset of NMOSD, increased permeability of the BBB causes the entry of circulating AQP4 autoantibodies into the central nervous system (CNS). Recent reports have shown the importance of glucose-regulated protein (GRP) autoantibodies as BBB-reactive autoantibodies in NMOSD, which induce antibody-mediated BBB dysfunction. BBB breakdown has also been observed in MOGAD, NPSLE, and AE with anti-NMDAR antibodies. Our recent report demonstrated the presence of GRP78 autoantibodies in patients with MOGAD and the molecular mechanism responsible for GRP78 autoantibody-mediated BBB impairment. Disruption of the BBB may explain the symptoms in the brain and cerebellum in the development of PNS, as it induces the entry of pathogenic autoantibodies or lymphocytes into the CNS through autoimmunity against tumors in the periphery. GRP78 autoantibodies were detected in paraneoplastic cerebellar degeneration and Lambert-Eaton myasthenic syndrome, and they were associated with cerebellar ataxia with anti-P/Q type voltage-gated calcium channel antibodies. This review reports that therapies affecting the BBB that are currently available for disease-modifying therapies for neuroimmunological diseases have the potential to prevent BBB damage.

FANCD2 genome binding is nonrandom and is enriched at large transcriptionally active neural genes prone to copy number variation

Fanconi anemia (FA) is a rare genetic disease characterized by congenital abnormalities and increased risk for bone marrow failure and cancer. Central nervous system defects, including acute and irreversible loss of neurological function and white matter lesions with calcifications, have become increasingly recognized among FA patients, and are collectively referred to as Fanconi Anemia Neurological Syndrome or FANS. The molecular etiology of FANS is poorly understood. In this study, we have used a functional integrative genomics approach to further define the function of the FANCD2 protein and FA pathway. Combined analysis of new and existing FANCD2 ChIP-seq datasets demonstrates that FANCD2 binds nonrandomly throughout the genome with binding enriched at transcription start sites and in broad regions spanning protein-coding gene bodies. FANCD2 demonstrates a strong preference for large neural genes involved in neuronal differentiation, synapse function, and cell adhesion, with many of these genes implicated in neurodevelopmental and neuropsychiatric disorders. Furthermore, FANCD2 binds to regions of the genome that replicate late, undergo mitotic DNA synthesis (MiDAS) under conditions of replication stress, and are hotspots for copy number variation. Our analysis describes an important targeted role for FANCD2 and the FA pathway in the maintenance of large neural gene stability.

Neurolymphomatosis mimicking a Guillain–Barré syndrome triggered by COVID‐19 vaccination

Guillain–Barré syndrome (GBS) is an acute disorder of the peripheral nervous system, causing flaccid paralysis, areflexia, and variable sensory involvement. Proximal as well distal muscles of the limbs can be involved, and in most severe and advanced cases progresses to respiratory failure and death. GBS is considered an autoimmune disease, and at the basis of the attack at the peripheral nervous system different mechanisms have been recognized, in particular viral infections or other immune stimulations. Cranial nerve involvement in patients with diffuse large B‐cell lymphoma (DLBCL) and primary central nervous system lymphoma are rare conditions that could present with similar clinical features. Here we present a case of a 36‐year‐old man hospitalized for acute polyradiculoneuritis of the cranial nerves and lumbar roots that arose a 14 days after severe acute respiratory syndrome COVID‐19 2 (Sars‐CoV‐2) vaccination. Most of the main criteria for the diagnosis of GBS were met, including clinical and electrophysiological criteria. Albuminocytologic dissociation and high protein level in cerebrospinal fluid were also found. Therefore, the patient was treated with a cycle of intravenous immunoglobulin (IVIG) with notable improvement of symptoms and gradual recovery of motility. A five months later, following SARS‐CoV‐2 infection, the patient presented with worsening of neurological symptoms and was readmitted to the hospital. He underwent instrumental tests again and was treated with repeated cycles of IVIG and then with a cycle of plasmapheresis without any improvement. In the following 10 days he developed very serious conditions; he was transferred to intensive care unit and deceased after 6 days. The cause of the neurological syndrome was determined only after autoptic analysis, which revealed the presence of primary peripheral nervous system (PNS) DLBCL. The reported case highlights that GBS‐like presentation always requires a careful differential diagnosis, and physicians should also consider the possibility of an occult cancer.

Temperature Dependence of the Pre-Chromatographic ‘Lawrence’ Method for Bivalves Contaminated with Paralytic Shellfish Poisoning Toxins

AbstractSaxitoxins are potent neurotoxins originating the acute human neurological syndrome of paralytic shellfish poisoning (PSP) via bivalve vectors. The official testing method in the European Union, commonly known as the ‘Lawrence method’, involves pre-column oxidation steps. The Portuguese monitoring adopted the hydrogen peroxide oxidation screening approach for bivalves contaminated with Gymnodinium catenatum toxins, which can quantify chromatographically at once 6 out of 10 analogues commonly found in bivalves. Seasonal fluctuation in the fluorescence yield of calibration curves was observed across years in a consistent manner. It correlated with fluctuations in average monthly air temperature in Lisbon, highlighting the importance of recording the room temperature during the oxidation steps as a matter of routine practice. Incubation experiments also showed an increase in fluorescence yield with temperature, more pronounced for the 11-hydroxysulphate analogues (dcGTX2 + 3, C1 + 2, GTX2 + 3) than for the 11-H toxins (dcSTX, GTX5[B1], STX). Temperature can be exploited to increase fluorescence yield, assisting in spectral confirmation, but must not exceed 40–50 °C to avoid toxin decomposition or production of extra oxidation products.

Clinical, neuropathological, and molecular characteristics of rapidly progressive dementia with Lewy bodies: a distinct clinicopathological entity?

BackgroundThe term rapidly progressive dementia (RPD) with Lewy bodies (rpDLB) is used for DLB patients who develop a rapidly progressive neurological syndrome and have reduced survival. Here, we characterise the clinical, neuropathological, and molecular characteristics of a large rpDLB neuropathological series.MethodsWe included all RPD patients with a disease duration < 4 years submitted to our prion disease referral centre between 2003 and 2022 who showed Lewy body pathology (LBP) in limbic or neocortical stages as primary neuropathological diagnosis, had no systemic condition justifying the rapid deterioration and were previously neurologically unimpaired. Clinical features were retrieved and compared with Creutzfeldt-Jakob disease (CJD) and rapidly progressive Alzheimer’s disease (rpAD) cohorts. Neuropathological and genetic (whole exome sequencing, APOE genotyping, and C9orf72 repeat expansion analysis) characteristics of rpDLB patients were systematically investigated. We scored semi-quantitatively the LBP load and performed a α-synuclein (αSyn) RT-QuIC seeding amplification assay (SAA) on cerebrospinal fluid (CSF) and tenfold serially diluted brain homogenates from different brain areas in rpDLB patients and typical long-lasting Lewy body disease (LBD) with dementia patients as control group.ResultsRpDLB patients were older (p = 0.047) and presented more cognitive fluctuations (p = 0.005), visual hallucinations (p = 0.020), neuropsychiatric symptoms (p = 0.006) and seizures (p = 0.032), and fewer cerebellar (p < 0.001) and visual (p = 0.004) signs than CJD ones. Delirium onset was more common than in both CJD (p < 0.001) and rpAD (p = 0.008). Atypical LBD signs (pyramidal, myoclonus, akinetic mutism) were common. All tested patients were positive by CSF αSyn SAA. Concomitant pathologies were common, with only four cases showing relatively “pure” LBP. LBP load and αSyn seeding activity measured through αSyn RT-QuIC SAA were not significantly different between rpDLB patients and typical LBD. We found a likely pathogenic variant in GBA in one patient.ConclusionsOur results indicate that: 1) rpDLB exhibits a distinct clinical signature (2) CSF αSyn SAA is a reliable diagnostic test; 3) rpDLB is a heterogeneous neuropathological entity that can be underlain by both widespread pure LBP, or multiple copathologies 4) rpDLB is likely not sustained by distinct αSyn conformational strains; 5) genetic defects may, at least occasionally, contribute to the poor prognosis in these patients.

Median nerve lesions in pediatric displaced supracondylar humerus fracture: A prospective neurological, electrodiagnostic and ultrasound characterization.

Supracondylar humerus fractures (SCHFs) are the most common elbow fractures in children. Traumatic median nerve injury and isolated lesions of its pure forearm motor branch, anterior interosseus nerve (AIN), have both been independently reported as complications of displaced SCHFs. Our main objectives were to characterize the neurological syndrome to distinguish median nerve from AIN lesions and to determine the prognosis of median nerve lesions after displaced SCHFs. Ten children were prospectively followed for an average of 11.6 months. Patients received a standardized clinical examination and high-resolution ultrasound of the median nerve every 1-3 months starting 1-2 months after trauma. Electrodiagnostic studies were performed within the first 4 months and after complete clinical recovery. All children shared a clinical syndrome with predominant but not exclusive affection of AIN innervated muscles. High-resolution ultrasound uniformly excluded persistent nerve entrapment and neurotmesis requiring revision surgery but visualized post-traumatic median nerve neuroma at the fracture site in all patients. Electrodiagnostic studies showed axonal motor and sensory median nerve neuropathy. All children achieved complete functional recovery under conservative management. Motor recovery required up to 11 months and differed between involved muscles. It was shown that neurological deficits of the median nerve in displaced SCHFs exceeded an isolated AIN lesion. Notably, detailed neurological follow-up examinations and sonographic exclusion of persistent nerve compression were able to guide conservative therapy in affected children. Under these conditions the prognosis of median nerve lesions was excellent despite severe initial deficits, development of neuroma and axonal injury.

Paraneoplastic neurological syndromes associated with anti-Hu antibodies in an ovarian cancer patient: a case report and narrative literature review

Paraneoplastic neurological syndromes associated with anti-Hu antibodies in an ovarian cancer patient: a case report and narrative literature review

Biallelic PTPMT1 variants disrupt cardiolipin metabolism and lead to a neurodevelopmental syndrome.

Primary mitochondrial diseases (PMDs) are among the most common inherited neurological disorders. They are caused by pathogenic variants in mitochondrial or nuclear DNA that disrupt mitochondrial structure and/or function, leading to impaired oxidative phosphorylation (OXPHOS). One emerging subcategory of PMDs involves defective phospholipid (PL) metabolism. Cardiolipin (CL), the signature PL of mitochondria, resides primarily in the inner mitochondrial membrane, where it is biosynthesised and remodelled via multiple enzymes and is fundamental to several aspects of mitochondrial biology. Genes that contribute to CL biosynthesis have recently been linked with PMD. However, the pathophysiological mechanisms that underpin human CL-related PMDs are not fully characterised. Here, we report six individuals, from three independent families, harbouring biallelic variants in PTPMT1, a mitochondrial tyrosine phosphatase required for de novo CL biosynthesis. All patients presented with a complex, neonatal/infantile onset neurological and neurodevelopmental syndrome comprising developmental delay, microcephaly, facial dysmorphism, epilepsy, spasticity, cerebellar ataxia and nystagmus, sensorineural hearing loss, optic atrophy, and bulbar dysfunction. Brain MRI revealed a variable combination of corpus callosum thinning, cerebellar atrophy, and white matter changes. Using patient-derived fibroblasts and skeletal muscle tissue, combined with cellular rescue experiments, we characterise the molecular defects associated with mutant PTPMT1 and confirm the downstream pathogenic effects that loss of PTPMT1 has on mitochondrial structure and function. To further characterise the functional role of PTPMT1 in CL homeostasis, we established a zebrafish ptpmt1 knockout model associated with abnormalities in body size, developmental alterations, decreased total CL levels, and OXPHOS deficiency. Together, these data indicate that loss of PTPMT1 function is associated with a new autosomal recessive PMD caused by impaired CL metabolism, highlight the contribution of aberrant CL metabolism towards human disease, and emphasise the importance of normal CL homeostasis during neurodevelopment.

Anti-RGS8 paraneoplastic cerebellar ataxia is preferentially associated with a particular subtype of Hodgkin’s lymphoma

Ataxia with anti-regulator of G-protein signaling 8 autoantibodies (RGS8-Abs) is an autoimmune disease recently described in four patients. The present study aimed to identify other patients with RGS8-Abs, describe their clinical features, including the link between RGS8-related autoimmune cerebellar ataxia (ACA) and cancer. Patients with RGS8-Abs were identified retrospectively in the biological collections of the French Reference Center for Paraneoplastic Neurological Syndrome and the University of California San Francisco Center for Encephalitis and Meningitis. Clinical data were collected, and cerebrospinal fluid, serum, and tumor pathological samples were retrieved to characterize the autoantibodies and the associated malignancies. Only three patients with RGS8-Abs were identified. All of them presented with a pure cerebellar ataxia of mild to severe course, unresponsive to current immunotherapy regimens for ACA. Two patients presented with a Hodgkin lymphoma of the rare specific subtype called nodular lymphocyte-predominant Hodgkin lymphoma, with very mild extension. Autoantibodies detected in all patients enriched the same epitope on the RGS8 protein, which is an intracellular protein physiologically expressed in Purkinje cells but also ectopically expressed specifically in lymphoma cells of patients with RGS8-related ACA. The present results and those of the four cases previously described suggest that RGS8-Abs define a new paraneoplastic neurological syndrome of extreme rarity found mostly in middle-aged males that associates pure cerebellar ataxia and a particular lymphoma specifically expressing the RGS8 antigen. As in other paraneoplastic ACA with intracellular antigen, the disease course is severe, and patients tend to exhibit a poor response to immune therapy.

Decoding Multiple Antibody Positivity: Lessons from Paraneoplastic Sensory Ataxia.

Paraneoplastic neurologic syndromes are cancer-associated, immune-mediated neurologic manifestations that may involve any part of the nervous system. They usually present with characteristic neurologic features and should be considered in high-risk phenotypes such as limbic encephalitis, encephalomyelitis, rapidly progressive cerebellar syndrome, opsoclonus-myoclonus, sensory neuronopathy, enteric neuropathy, and Lambert-Eaton myasthenic syndrome. The diagnosis is made by antibody positivity in the serum or cerebrospinal fluid, in the presence of an appropriate clinical phenotype. Findings on antibody testing by immunoblot should always be verified by immunofluorescence. We report a rare case of sensory neuronopathy with triple paraneoplastic antibody positivity (anti-Hu, anti-collapsing response-mediator protein 5, and anti-amphiphysin) on immunoblot but only anti-Hu positivity on immunofluorescence. The presence of lower facial dyskinesias should raise the possibility of an immune-mediated neurologic syndrome in the appropriate clinical context.

Beyond paraneoplastic neurological syndromes: Anti-neuronal antibodies in neuropsychiatric systemic lupus erythematosus.

Anti-neuronal antibodies target antigens produced by tumour cells and cells of nervous system. These antibodies are formed as a result of autoimmune response elicited by the underlying malignancy, when proteins restricted to immune privileged neurons are presented by the tumour. Previous studies have shown presence of anti-neuronal antibodies in systemic lupus erythematosus and neuropsychiatric lupus (NPSLE) but information on individual antibodies and their pathogenic role is lacking. To assess the frequency of anti-neuronal antibodies in our neuropsychiatric lupus cohort and to assess any significant association with specific neurological syndrome and to see if the antibodies were more likely to occur in active rather than inactive neuropsychiatric lupus. This cross-sectional study was conducted in our center from 2019 to 2022. Neuropsychiatric manifestations were defined according to 1999 American College of Rheumatology (ACR) nomenclature and case definitions for neuropsychiatric lupus. Samples were taken from active or inactive NPSLE patients with their informed consent. Testing was done on an anti-neuronal antigen panel which consisted of [Amphiphysin, CV2, GAD 65, PNMA2 (Ma-2/Ta), Ri, Yo, Hu, recoverin, SOX1, titin, Zic, Tr)] by semi-quantitative Line immune assay. Association between the categorical variables and antibody positivity group was established using chi-square/Fisher's exact test as appropriate. 65 patients were recruited, of which 23 (35%) patients had active NPSLE at the time of sample collection. Anti-neuronal antibodies were positive in 13/65 (20%) patients with anti-Gad 65 antibodies having the highest frequency (6.2%) followed by anti CV 2 (3.1%), anti Sox1 (3.1%), anti Amphiphysin (3.1%) anti recoverin (1.5%), anti Yo (1.5%) and anti Zic (1.5%). The panel of anti-neuronal antibodies did not show any specific association with NPSLE features.However, an interesting finding was that, patients with active disease had higher odds of having anti-neuronal antibodies with an OR = 10 (95% CI:2.38 -42) (p < 0.001) than inactive disease. Anti-neuronal antibodies were more likely to be positive in active neuropsychiatric lupus patients, and these antibodies which are commonly used to diagnose paraneoplastic syndromes may have a potential role in the diagnosis of NPSLE.

Post-traumatic cognitive disorders: the cholinergic therapy options

Traumatic brain injury (TBI) is one of the most common causes of neurological disability in young and middle-aged people. Cognitive impairment is the most persistent and universal brain injury syndrome in cases of TBI and, moreover, the best indicator of TBI severity to predict its outcome. Cognitive impairment can persist persistently even after mild TBI, which accounts for 70–90 % of the total number of trauma patients. This may be due to the fact that in cases of mild TBI, the most fragile functions of integrative structures of the frontal and temporal lobes are slowly and not always completely recovered and the dominant clinical manifestation become complex neuropsychological disorders. Individuals with repeated mild TBI are characterized by development of chronic post-traumatic encephalopathy, that is a kind of neurodegenerative disease manifested by slowly increasing cognitive impairment, parkinsonism and a number of other neurological syndromes. Early detection and adequate correction of the cognitive impairments may improve the outcome of injury of diverging severity. Due to the fact that the pathogenesis of TBI is based on disorder of cholinergic system, the patients have predominance of regulatory disorders in the neuropsychological profile, as well as a combination of cognitive and affective disorders. Administration of acetylcholine precursors leads to rapid increase of free choline levels in plasma that penetrates the blood-brain barrier well and enhances cholinergic activity by increasing acetylcholine synthesis and release. The article considers the possibilities of using acetylcholine precursors in connection with their potential to block the progressive impairment of cognitive functions induced by trauma as well as to reduce severity of behavioral and affective disorders.

In Vivo Prevalence of Beta-Amyloid Pathology and Alzheimer's Disease Co-Pathology in Idiopathic Normal-Pressure Hydrocephalus-Association with Neuropsychological Features.

Idiopathic normal-pressure hydrocephalus (iNPH) is a clinic-radiological neurological syndrome presenting with cognitive deficits, gait disturbances and urinary incontinence. It often coexists with Alzheimer's disease (AD). Due to the reversible nature of iNPH when promptly treated, a lot of studies have focused on possible biomarkers, among which are cerebrospinal fluid (CSF) biomarkers. The aim of the present study was to determine the rate of beta-amyloid pathology and AD co-pathology by measuring AD CSF biomarkers, namely, amyloid beta with 42 and 40 amino acids (Aβ42), the Aβ42/Aβ40 ratio, total Tau protein (t-Tau) and phosphorylated Tau protein at threonine 181 (p-Tau), in a cohort of iNPH patients, as well as to investigate the possible associations among CSF biomarkers and iNPH neuropsychological profiles. Fifty-three patients with iNPH were included in the present study. CSF Aβ42, Aβ40, t-Tau and p-Tau were measured in duplicate with double-sandwich ELISA assays. The neuropsychological evaluation consisted of the Mini-Mental State Examination, Frontal Assessment Battery, Five-Word Test and CLOX drawing tests 1 and 2. After statistical analysis, we found that amyloid pathology and AD co-pathology are rather common in iNPH patients and that higher values of t-Tau and p-Tau CSF levels, as well as the existence of the AD CSF profile, are associated with more severe memory impairment in the study patients. In conclusion, our study has confirmed that amyloid pathology and AD-co-pathology are rather common in iNPH patients and that CSF markers of AD pathology and t-Tau are associated with a worse memory decline in these patients.

Anterior Cingulate Cortex Contributes to the Hyperlocomotion under Nitrogen Narcosis.

Nitrogen narcosis is a neurological syndrome that manifests when humans or animals encounter hyperbaric nitrogen, resulting in a range of motor, emotional, and cognitive abnormalities. The anterior cingulate cortex (ACC) is known for its significant involvement in regulating motivation, cognition, and action. However, its specific contribution to nitrogen narcosis-induced hyperlocomotion and the underlying mechanisms remain poorly understood. Here we report that exposure to hyperbaric nitrogen notably increased the locomotor activity of mice in a pressure-dependent manner. Concurrently, this exposure induced heightened activation among neurons in both the ACC and dorsal medial striatum (DMS). Notably, chemogenetic inhibition of ACC neurons effectively suppressed hyperlocomotion. Conversely, chemogenetic excitation lowered the hyperbaric pressure threshold required to induce hyperlocomotion. Moreover, both chemogenetic inhibition and genetic ablation of activity-dependent neurons within the ACC reduced the hyperlocomotion. Further investigation revealed that ACC neurons project to the DMS, and chemogenetic inhibition of ACC-DMS projections resulted in a reduction in hyperlocomotion. Finally, nitrogen narcosis led to an increase in local field potentials in the theta frequency band and a decrease in the alpha frequency band in both the ACC and DMS. These results collectively suggest that excitatory neurons within the ACC, along with their projections to the DMS, play a pivotal role in regulating the hyperlocomotion induced by exposure to hyperbaric nitrogen.

Preclinical Assessment of a Cannabinoid CB2 Receptor Antagonist in a Murine Model of Cerebral Malaria

Malaria is a most important parasitic disease due to its highest impact worldwide. It results in around 200 million clinical cases and 0,5-1 million deaths per year, mainly due to cerebral malaria (CM), a life-threatening neurological syndrome that predominantly affects predominantly children under five years old. CM follows neurological alterations leading to the death if left untreated, and, even when it is treated, it is fatal in 15-20% of cases. Moreover, among the survivors, more than 10% of the children develop neurological sequelae. Consequently, there is an urgent need to find therapies to attenuate these neurological signs. Recent evidence has proposed the endocannabinoid system, which plays an important neuromodulatory function in the central nervous system (CNS), also including immunomodulation preferentially exerted by CB2 receptor. Previous studies have shown that the genetic ablation of this receptor improved mice survival against CM, suggesting a potential for the pharmacological treatment of CM with selective antagonists of this receptor. Considering this background, we investigated CM therapy by a classic CB2 antagonist SR144528 in a murine model of the disease. First, we carried out binding studies with SR144528 to confirm its pharmacodynamic profile (binding affinity [Ki] value = 2.34 ± 0.61 nM; and efficacy [IC50] = 96.17 ± 1.41 nM, at the CB2 receptor). Second, P. berghei ANKA infected C57BL/6 mice were treated daily with SR144528 and assessed for parasitemia growth and neurological alterations. 30% of the treated mice showed partial recovery of CM symptoms with 20% increased survival, but finally succumbing to hyperparasitemia and severe anemia. These preliminary preclinical results suggest that, although part of the CM course might be modulated by the pharmacological blockade of the CB2 receptor, other elements trigger the lethal outcome. Thus, while our hypothesis could not be completely validated in this CM model, we detail here all obtained results for further research.

Central Nervous System Involvement in Systemic Autoimmune Rheumatic Diseases-Diagnosis and Treatment.

Central nervous system (CNS) involvement in autoimmune rheumatic diseases represents a significant challenge for clinicians across all specialties. While most reviews on the subject focus on neurological manifestations within a specific rheumatic disease, few descriptions shift from neurological clinical syndromes to achieve rheumatological diagnoses. This narrative review aims to synthesize current knowledge on the diagnosis and management of CNS manifestations occurring in the most prevalent rheumatic conditions in adults. We searched the MEDLINE database using the terms "central nervous system", "rheumatic diseases", "systemic lupus erythematosus", "rheumatoid arthritis", "Sjögren syndrome", and "vasculitis". The search strategy included review articles from 2019 to 2024, published in English, Spanish, or Portuguese. We explored the pathophysiological mechanisms linking autoimmunity to CNS pathology, emphasizing the role of syndromic reasoning, autoantibody profiles, and imaging modalities as tools for diagnosis and determination of inflammatory activity. The review also discusses differential diagnoses through a stepwise approach to neurological syndromes, summarized in diagnostic flowcharts, and presents updated treatment options. Although our approach is primarily semiology-based, the complexity of the subject invites future endeavors involving new technologies, such as functional MRI, MR spectroscopy, and nuclear medicine.

Quercetin/polyethyleneimine modified gold nanoconjugates inhibit apoptosis and ROS production induced by hydrogen peroxide in DRG sensory neurons

The basis of most neurological syndromes is the accumulation of free radical molecules. Quercetin is a polyphenolic bioflavonoid molecule and it has a very strong antioxidant effect by maintaining oxidative balance. There are many difficulties in the clinical use of quercetin due to its hydrophobic structure, low solubility, instability, poor oral bioavailability, and limited tissue-barrier penetration. Its synergistic use in complex with gold nanoparticles (AuNPs) could overcome these problems. AuNPs have recently emerged as an attractive candidate for delivery applications of various biomolecules and drugs. The aim of this study was to synthesize two different sized gold nanoparticles (AuNP20 and AuNP50) modified with polyethyleneimine (PEI) and quercetin, evaluate their potential neuroprotective effects on the in vitro oxidative stress model using DRG primary sensory neurons. It was shown that the antioxidant and anti-apoptotic ability of the bioflavonoid was preserved after exposure to the designed quercetin modified AuNPs. The PEI surface coating increased the stability and biocompatibility of the AuNPs in both sizes. It also potentially enables additional surface functionalization. This study indicates that designed nanoparticles (AuNP-Q-PEI) with different sizes could be a useful potential platform for the treatment of neurodegenerative syndromes or cancer diseases.

Paraneoplastic Neurologic Disorders.

This article reviews the clinical presentations, neural antibody associations, and oncologic accompaniments of paraneoplastic neurologic syndromes and neurologic autoimmunity in the context of immune checkpoint inhibitor (ICI) cancer immunotherapy. Neural antibody discovery has improved the diagnosis of paraneoplastic neurologic syndromes. Neural antibodies also delineate the underlying disease pathophysiology and thus inform outcomes and treatments. Neural antibodies specific for extracellular proteins have pathogenic potential, whereas antibodies specific for intracellular targets are biomarkers of a cytotoxic T-cell immune response. A recent update in paraneoplastic neurologic syndrome criteria suggests high- and intermediate-risk phenotypes as well as neural antibodies to improve diagnostic accuracy in patients with paraneoplastic neurologic syndromes; a score was created based on this categorization. The introduction of ICI cancer immunotherapy has led to an increase in cancer-related neurologic autoimmunity with distinct clinical phenotypes. Paraneoplastic neurologic syndromes reflect an ongoing immunologic response to cancer mediated by effector T cells or antibodies. Paraneoplastic neurologic syndromes can present with manifestations at any level of the neuraxis, and neural antibodies aid diagnosis, focus cancer screening, and inform prognosis and therapy. In patients with high clinical suspicion of a paraneoplastic neurologic syndrome, cancer screening and treatment should be undertaken, regardless of the presence of a neural antibody. ICI therapy has led to immune-mediated neurologic complications. Recognition and treatment lead to improved outcomes.