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Intra-operative ultrasound has become a relevant imaging modality in neurosurgical procedures. While B-mode, with its intrinsic limitations, is still considered the primary ultrasound modality, intra-operative contrast-enhanced ultrasound (ioCEUS) has more recently emerged as a powerful tool in neurosurgery. Though still not used on a large scale, ioCEUS has proven its utility in defining tumor boundaries, identifying lesion vascular supply and mapping neurovascular architecture. Here we propose a step-by-step procedure for performing ioCEUS analysis of the brain, highlighting its neurosurgical applications. Moreover, we provide practical advice on the use of ultrasound contrast agents and review technical ultrasound parameters influencing ioCEUS imaging.

BACKGROUND Intraoperative diagnosis of central nervous system (CNS) tumors provides critical guidance to surgeons in the determination of surgical resection margins and treatment. The techniques and preparations used for the intraoperative diagnosis of CNS tumors include frozen sectioning and cytologic methods (squash smear and touch imprint). Cytologic specimens, which do not have freezing artifacts, are important as an adjuvant tool to frozen sections. However, if the amount of submitted tissue samples is limited, then it is difficult to prepare both frozen sections and squash smears or touch imprint specimens from a single sample at the same time. Therefore, the objective of this study was to derive cells directly from filter paper on which tumor samples are placed. METHODS The authors established the filter paper-assisted cell transfer (FaCT) smear technique, in which tumor cells are transferred onto a glass slide directly from the filter paper sample spot after the biopsy is removed. RESULTS Cell yields and diagnostic accuracy of the FaCT smears were assessed in 40 CNS tumors. FaCT smears had ample cell numbers and well preserved cell morphology sufficient for cytologic diagnosis, even if the submitted tissues were minimal. The overall diagnostic concordance rates between frozen sections and FaCT smears were 90% and 87.5%, respectively (no significant differences). When combining FaCT smears with frozen sections, the diagnostic concordance rate rose to 92.5%. CONCLUSIONS The current results suggest that the FaCT smear technique is a simple and effective processing method that has significant value for intraoperative diagnosis of CNS tumors. Cancer Cytopathol 2017;125:277–282. © 2016 American Cancer Society.

The Society of Toxicologic Pathology charged a Nervous System Sampling Working Group with devising recommended practices to routinely screen the central nervous system (CNS) and peripheral nervous system (PNS) in Good Laboratory Practice–type nonclinical general toxicity studies. Brains should be weighed and trimmed similarly for all animals in a study. Certain structures should be sampled regularly: caudate/putamen, cerebellum, cerebral cortex, choroid plexus, eye (with optic nerve), hippocampus, hypothalamus, medulla oblongata, midbrain, nerve, olfactory bulb (rodents only), pons, spinal cord, and thalamus. Brain regions may be sampled bilaterally in rodents using 6 to 7 coronal sections, and unilaterally in nonrodents with 6 to 7 coronal hemisections. Spinal cord and nerves should be examined in transverse and longitudinal (or oblique) orientations. Most Working Group members considered immersion fixation in formalin (for CNS or PNS) or a solution containing acetic acid (for eye), paraffin embedding, and initial evaluation limited to hematoxylin and eosin (H&E)-stained sections to be acceptable for routine microscopic evaluation during general toxicity studies; other neurohistological methods may be undertaken if needed to better characterize H&E findings. Initial microscopic analyses should be qualitative and done with foreknowledge of treatments and doses (i.e., “unblinded”). The pathology report should clearly communicate structures that were assessed and methodological details. Since neuropathologic assessment is only one aspect of general toxicity studies, institutions should retain flexibility in customizing their sampling, processing, analytical, and reporting procedures as long as major neural targets are evaluated systematically.

Virus infections of the central nervous system (CNS) may result in the loss of myelin sheaths without axonal destruction. Severe neurological symptoms occur as a consequence of this phenomenon which is called primary demyelination. The sequence of events leading to primary demyelination during the course of viral infections of the CNS is only partially understood. Although it is well established that cytolytic infection of the Oligodendroglia cell can cause primary demyelination, mononuclear infiltrates in subacute and chronic courses of the disease indicate that immunological events may take part in this process (reviewed by Johnson (1)). For several reasons, investigations into the dynamic interactions between virus infection of the CNS and the local immune response cannot be conducted in man. (1) Usually clinical specimens are restricted to cerebrospinal fluid which gives limited information about pathological events occuring in the brain parenchyma (2). It is not known at which time point of the preceeding systemic infection, the virus enters the brain and biopsies are taken too rarely and infrequently to understand the kinetics of the events (3). The general absence of genetic homogeneity in man complicates attempts to detect the influence of the immunogenetic background on the course of the disease. In contrast, intracerebral infections of rodents with the murine hepatitis virus JHM (MHV-4) are excellent models to study the relationships between virus-induced demyelination and the local immune response. Based on the work of Cheever (2), animal models of JHM virus-induced demyelinating encephalomyelitis have been developed in mice as well as in rats (3–5). In recent years striking similarities in the course of the infection in both rodents have been detected which might give the impression that these two models can substitute for each other. However, subtle but important differences do exist. Therefore, in the present review attempts are made to summarize and compare the knowledge about demyelinating encephalomyelitides in rats and mice, giving emphasis to the role of the local immune response in the brain.

A century ago this year, Pío del Río‐Hortega (1921) coined the term ‘oligodendroglia’ for the ‘interfascicular glia’ with very few processes, launching an extensive discovery effort on his new cell type. One hundred years later, we review his original contributions to our understanding of the system of cytoplasmic channels within myelin in the context of what we observe today using light and electron microscopy of genetically encoded fluorescent reporters and immunostaining. We use the term myelinic channel system to describe the cytoplasm‐delimited spaces associated with myelin; being the paranodal loops, inner and outer tongues, cytoplasm‐filled spaces through compact myelin and further complex motifs associated to the sheath. Using a central nervous system myelinating cell culture model that contains all major neural cell types and produces compact myelin, we find that td‐tomato fluorescent protein delineates the myelinic channel system in a manner reminiscent of the drawings of adult white matter by Río‐Hortega, despite that he questioned whether some cytoplasmic figures he observed represented artefact. Together, these data lead us to propose a slightly revised model of the ‘unrolled’ sheath. Further, we show that the myelinic channel system, while relatively stable, can undergo subtle dynamic shape changes over days. Importantly, we capture an under‐appreciated complexity of the myelinic channel system in mature myelin sheaths., Using fluorescent reporter protein and immunostaining we revisit Pío del Río‐Hortega’s exquisite drawings of the cytoplasm of CNS myelin. Together, these data highlight an under‐appreciated complexity of the myelinic channel system. We employ 3D reconstructions to illustrate some key features.

Silicon dioxide nanoparticles (SiO2 NPs) are widely invested in medicine, industry, agriculture, consuming products, optical imaging agents, cosmetics, and drug delivery. However, the toxicity of these NPs on human health and the ecosystem have not been extensively studied and little information is available about their behavioural toxicities. The current study aimed to find out the behavioural alterations that might be induced by chronic exposure to 10 nm SiO2 NPs. BALB/C mice were subjected to 36 injections of SiO2 NPs (2 mg/kg Bw) and subjected to 11 neurobehavioural tests: elevated plus‐maze test, elevated zero‐maze test, multiradial maze test, open field test, hole‐board test, light‐dark box test, forced swimming test, tail‐suspension test, Morris water‐maze test, Y‐maze test and multiple T‐maze test. Treated mice demonstrated anxiety‐like effect, depression tendency, behavioural despair stress, exploration and locomotors activity reduction with error induction in both reference and working memories. The findings may suggest that silica NPs are anxiogenic and could aggravate depression affecting memory, learning, overall activity and exploratory behaviour. Moreover, the findings may indicate that these nanomaterials (NMs) may induce potential oxidative stress in the body leading to neurobehavioural alterations with possible changes in the vital organ including the central nervous system.

Sex hormones, including androgens and estrogens, play an important role in autonomic, reproductive and sexual behavior. The areas that are important in these behaviors lie within the spinal cord and brainstem. Relevant dysfunctional behavior in patients with altered androgen availability or androgen receptor sensitivity might be explained by the distribution of androgens and their receptors in the central nervous system. We hypothesize that autonomic dysfunction is correlated with the androgen sensitivity of spinal cord and brainstem areas responsible for autonomic functions. In this study, androgen receptor immunoreactive (AR‐IR) nuclei in the spinal cord and brainstem were studied using the androgen receptor antibody PG21 in four uncastrated young adult male cats. A dense distribution of AR‐IR nuclei was detected in the superior layers of the dorsal horn, including lamina I. Intensely stained nuclei, but less densely distributed, were found in lamina X and preganglionic sympathetic and parasympathetic cells of the intermediolateral cell column. Areas in the caudal brainstem showing a high density of AR‐IR nuclei included the area postrema, the dorsal motor vagus nucleus and the retrotrapezoid nucleus. More cranially, the central linear nucleus in the pons contained a dense distribution of AR‐IR nuclei. The mesencephalic periaqueductal gray (PAG) showed a dense distribution of AR‐IR nuclei apart from the most central part of the PAG directly adjacent to the ependymal lining. Other areas in the mesencephalon with a dense distribution of AR‐IR nuclei were the dorsal raphe nucleus, the retrorubral nucleus, the substantia nigra and the ventral tegmental area of Tsai. It is concluded that AR‐IR nuclei are located in specific areas of the central nervous system that are involved in the control of sensory function and autonomic behavior. Furthermore, damage of these AR‐IR areas might explain related dysfunction in humans., In this study, androgen receptor immunoreactive (AR‐IR) nuclei in the spinal cord and brainstem were studied using the androgen receptor antibody PG21 in four uncastrated young adult male cats. It is concluded that AR‐IR nuclei are located in specific areas of the central nervous system that are involved in the control of sensory function and autonomic behavior. Furthermore, damage of these AR‐IR areas might explain related dysfunction in humans.

Traumatic spinal cord injury is a fatal acute event without effective clinical therapies. Following the trauma, immediate neural protection and microenvironment mitigation are vitally important for nerve tissue repair, where stem cell-based therapies could be eclipsed by the deficiency of cells due to the hostile microenvironment as well as the transport and preservation processes. Effective emergency strategies are required to be convenient, biocompatible, and stable. Herein, we assess an emergency cell-free treatment using mesenchymal stem cell-derived exosomes, which have proven capable of comprehensive mitigation of the inhibitory lesion microenvironment. The clinically validated fibrin glue is utilized to encapsulate the exosomes and in-situ gelates in transected rat spinal cords to provide a substrate for exosome delivery as well as nerve tissue growth. The emergency treatment alleviates the inflammatory and oxidative microenvironment, inducing effective nerve tissue repair and functional recovery. The therapy presents a promising strategy for effective emergency treatment of central nervous system trauma., Graphical Abstract Graphical abstract Image, graphical abstract

The paper describes modifications of microwave techniques for in vivo rapid inactivation of brain enzymes. These modified techniques offer greater rapidity and homogeneity of inactivation. The microwave-treated brain remains suitable for regional dissection.

Introduction Juvenile-onset systemic lupus erythematosus (JSLE) is a rare autoimmune/inflammatory disease with significant morbidity and mortality. Neuropsychiatric (NP) involvement is a severe complication, encompassing a heterogeneous range of neurological and psychiatric manifestations. Methods Demographic, clinical, and laboratory features of NP-SLE were assessed in participants of the UK JSLE Cohort Study, and compared to patients in the same cohort without NP manifestations. Results A total of 428 JSLE patients were included in this study, 25% of which exhibited NP features, half of them at first visit. Most common neurological symptoms among NP-JSLE patients included headaches (78.5%), mood disorders (48.6%), cognitive impairment (42%), anxiety (23.3%), seizures (19.6%), movement disorders (17.7%), and cerebrovascular disease (14.9%). Peripheral nervous system involvement was recorded in 7% of NP-SLE patients. NP-JSLE patients more frequently exhibited thrombocytopenia (9/L) ( p = 0.04), higher C-reactive protein levels ( p = 0.01), higher global pBILAG score at first visit ( p < 0.001), and higher SLICC damage index score at first ( p = 0.02) and last ( p < 0.001) visit when compared to JSLE patients without NP involvement. Conclusions A significant proportion of JSLE patients experience NP involvement (25%). Juvenile-onset NP-SLE most commonly affects the CNS and is associated with increased overall disease activity and damage.

1. Varying degrees of functional activity and fatigue were induced in white rats by prolonged swimming. 2. Microscopical examination of Nissl preparations from the cerebellum, cervical cord, and spinal ganglia revealed mild but demonstrable nerve-cell alterations. 3. These were strikingly similar in character to those previously observed in parathyroid tetany dogs and cretin lambs. 4. Chromatolysis is considered as a general reaction of nerve cells, which invariably occurs whenever the normal functional equilibrium of these units is disturbed. 5. This reaction varies in its intensity with the severity of the opposing influence, and to this extent only can it be spoken of as specific.

1. Complete thyroparathyroidectomy was performed on thirteen dogs, with the result that all except one developed typical tetany in some degree within one to fourteen days. The one not showing these symptoms was killed on the twenty-second day after the operation, to be used as an operated control. The tissue from three normal dogs supplied the necessary control material. 2. The symptoms of parathyroid tetany suggest an acute affection of the nervous system, especially of the nerve centres. This fact is strongly supported by microscopic alterations found in the nerve cells, the degree of which corresponds very closely to the acuteness of the attacks. These pictures point to a condition of general toxaemia. 3. Not all cells of a single animal or even of a single nerve-nucleus are affected to the same extent, so that for the same animal various steps in the reaction can be recognised. The alterations cannot be considered as the result of activity alone, but are interpreted as being produced by the same agent or agents which act as stimuli upon the neuromuscular mechanism. 4. A careful study of the nerve cells from Nissl preparations has been made, taking representative sections from the spinal cord, medulla oblongata, cerebellum, pons, mid-brain, thalamus, and cruciate gyrus. 5. The nerve cells of dog C, the operated control, are well within the normal. In the remaining twelve animals definite although varying degrees of alterations were found in these elements. In general, one might say that these changes are proportional to the acuteness of the tetanic affection. The milder grades of tetany, although extending over several days, are less drastic in their effects as measured by nerve-cell reaction than more acute attacks of a few hours' duration. 6. Sufficiently graduated stages are represented to warrant an account of the course of the affection. Early in the chromatolytic reaction, as measured by the severity of the symptoms, there is a stage of absolute hyperchromatosis with shrinkage of the cells, after which the amount of stainable material gradually diminishes through fragmentation and dissolution. This begins in the perinuclear region and spreads towards the periphery until a stage is reached in which normal staining Nissl substance can no longer be demonstrated. 7. The nucleus, on the other hand, seems to maintain its integrity to a greater extent. Except that it is slightly swollen and clouded, it appears to be normal. Complete degeneration of the cells, with karyorrhexis or karyolysis, was not seen; and in very few cells, if any, did it appear that the alterations were beyond repair had it been possible to restore the normal condition of the animal. 8. Shifting of the nucleus toward the periphery, although occasionally seen, occurred no more frequently in the experimental than in the control tissues. Vacuolisation of the cytoplasm commonly accompanied the most acute affection, particularly in the Purkinje cells and granule cells of the cerebrum. This was often associated with perivascular and pericellular œdema. 9. The associated hyperpyrexia was roughly proportional to the severity of the tetanic spasms, and followed rather than preceded the latter. This increase in body temperature is sufficient by itself to produce changes in the nerve cells, and undoubtedly exaggerates the condition of general poisoning. But this alone cannot account for the nerve-cell alterations, since these occur in milder form in animals whose temperature remains about normal. 10. This work offers insufficient proof of the conclusion that there is an increase in the number of glia cells, or that the processes can be seen for greater distances from the cell-bodies. Little importance is attached to these findings of other observers.

As the mammalian central nervous system matures, its regenerative ability decreases, leading to incomplete or non‐recovery from the neurodegenerative diseases and central nervous system insults that we are increasingly facing in our aging world population. Current neuroregenerative research is largely directed toward identifying the molecular and cellular players that underlie central nervous system repair, yet it repeatedly ignores the aging context in which many of these diseases appear. Using an optic nerve crush model in a novel biogerontology model, that is, the short‐living African turquoise killifish, the impact of aging on injury‐induced optic nerve repair was investigated. This work reveals an age‐related decline in axonal regeneration in female killifish, with different phases of the repair process being affected depending on the age. Interestingly, as in mammals, both a reduced intrinsic growth potential and a non‐supportive cellular environment seem to lie at the basis of this impairment. Overall, we introduce the killifish visual system and its age‐dependent regenerative ability as a model to identify new targets for neurorepair in non‐regenerating individuals, thereby also considering the effects of aging on neurorepair., In contrast to findings in zebrafish, this study reveals a striking age‐related decline in optic nerve regeneration in the short‐living killifish, with different phases of the repair process being affected depending on the age. Interestingly, while resembling zebrafish at young age, the regenerative ability is more mammalian‐like at old age. As in mammals, both a reduced intrinsic growth potential and a non‐supportive cellular environment seem to lie at the basis of impaired nerve regeneration.

Mitochondrial DNA (mtDNA) heteroplasmy is the dynamically determined co-expression of wild type (WT) inherited polymorphisms and collective time-dependent somatic mutations within individual mtDNA genomes. The temporal expression and distribution of cell-specific and tissue-specific mtDNA heteroplasmy in healthy individuals may be functionally associated with intracellular mitochondrial signaling pathways and nuclear DNA gene expression. The maintenance of endogenously regulated tissue-specific copy numbers of heteroplasmic mtDNA may represent a sensitive biomarker of homeostasis of mitochondrial dynamics, metabolic integrity, and immune competence. Myeloid cells, monocytes, macrophages, and antigen-presenting dendritic cells undergo programmed changes in mitochondrial metabolism according to innate and adaptive immunological processes. In the central nervous system (CNS), the polarization of activated microglial cells is dependent on strategically programmed changes in mitochondrial function. Therefore, variations in heteroplasmic mtDNA copy numbers may have functional consequences in metabolically competent mitochondria in innate and adaptive immune processes involving the CNS. Recently, altered mitochondrial function has been demonstrated in the progression of coronavirus disease 2019 (COVID-19) due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Accordingly, our review is organized to present convergent lines of empirical evidence that potentially link expression of mtDNA heteroplasmy by functionally interactive CNS cell types to the extent and severity of acute and chronic post-COVID-19 neurological disorders.

Neural stem cells (NSC) restrict their differentiation potential as the central nervous system develops. Experimental evidence suggests that the mechanisms governing the transition from the neurogenic to the gliogenic phase irreversibly affect the ability of NSC to generate neurons. Cell cycle regulation has been associated with cell fate in different models. In this work, we assessed the temporal correlation between the loss of the neurogenic potential and cell cycle lengthening of NSC obtained from embryonic mouse spinal cords, during the transition of the neurogenic to the gliogenic phase, using neurospheres. We also used the cell cycle inhibitor Olomoucine to increase cell cycle length by decreasing the proliferation rate. Our results show that neurospheres obtained from a neurogenic stage give rise mostly to neurons, whereas those obtained from later stages produce preferentially glial cells. During the transition from neurogenesis to gliogenesis, the proliferation rate dropped, and the cell cycle length increased 1.5 folds, as monitored by DNA BrdU incorporation. Interestingly, Olomoucine-treated neurogenic-neurospheres display a reduced proliferation rate and preserve their neurogenic potential. Our results suggest that the mechanisms that restrict the differentiation potential of NSC are independent of the proliferation control., Highlights • Neurosphere cultured, spinal cord NSC preserve their differentiation potential. • Neurogenic NSC divide faster than those giving rise to glial cells. • Cell cycle inhibitors increase in NSC transitioning from the neurogenic to the gliogenic phase. • Artificial cell cycle lengthening does not affect the differentiation potential of neurogenic NSC.

Purpose: Electrical epidural spinal cord stimulation (SCS) is used as a treatment for chronic pain as well as to partially restore motor function after a spinal cord injury. Monitoring the spinal cord activity during SCS with fMRI could provide important and objective measures of integrative responses to treatment. Unfortunately, spinal cord fMRI is severely challenged by motion and susceptibility artifacts induced by the implanted electrode and bones. This pilot study introduces multi-band sweep imaging with Fourier transformation (MB-SWIFT) technique for spinal cord fMRI during SCS in rats. Given the close to zero acquisition delay and high bandwidth in 3 dimensions, MB-SWIFT is demonstrated to be highly tolerant to motion and susceptibility-induced artifacts and thus holds promise for fMRI during SCS. Methods: MB-SWIFT with 0.78 × 0.78 × 1.50 mm3 spatial resolution and 3-s temporal resolution was used at 9.4 Tesla in rats undergoing epidural SCS at different frequencies. Its performance was compared with spin echo EPI. The origin of the functional contrast was also explored using suppression bands. Results: MB-SWIFT was tolerant to electrode-induced artifacts and respiratory motion, leading to substantially higher fMRI sensitivity than spin echo fMRI. Clear stimulation frequency-dependent responses to SCS were detected in the rat spinal cord close to the stimulation site. The origin of MB-SWIFT fMRI signals was consistent with dominant inflow effects. Conclusion: fMRI of the rat spinal cord during SCS can be consistently achieved with MB-SWIFT, thus providing a valuable experimental framework for assessing the effects of SCS on the central nervous system. publishedVersion

Acute disseminated encephalomyelitis (ADEM) is an autoimmune, central nervous system demyelinating disorder that follows antecedent immunologic challenges, such as infection or vaccination. This study aimed to investigate the potential association between routine childhood vaccinations and ADEM. Children under 7 years of age admitted to the two tertiary level pediatric hospitals in Victoria, Australia with ADEM from 2000–2015 had their clinical information linked to vaccination records from the Australian Childhood Immunization Register. Chart review was undertaken utilizing the Brighton Collaboration ADEM criteria. The self-controlled case-series (SCCS) methodology was employed to determine the relative incidences of ADEM post-vaccination in two risk intervals: 5–28 days and 2–42 days. Forty-six cases were eligible for SCCS analysis with a median age of 3.2 years. Of the forty-six cases, three were vaccine proximate cases and received vaccinations 23, 25 and 28 days before ADEM onset. Two vaccine proximate cases received their 4-year-old scheduled vaccinations (MMR and DTPa-IPV) and one vaccine proximate case the 1-year old scheduled vaccinations (MMR and Hib-MenC). The relative incidence of ADEM during the narrow and broad risk intervals were 1.041 (95% CI 0.323–3.356, p = 0.946) and 0.585 (95% CI 0.182–1.886, p = 0.370) respectively. Sensitivity analyses did not yield any substantial deviations. These results do not provide evidence of an association between vaccinations routinely provided to children aged under 7 years in Australia and the incidence of ADEM. However, these results should be interpreted with caution as the number of ADEM cases identified was limited and further research is warranted.

Suture-line injections of onabotulinumtoxinA alter a neuronal function along a central nervous system pathway involved in the pathophysiology of migraine that is secondary to appearance of SNAP25 in dural nerve fibers., OnabotulinumtoxinA (BoNT-A) is an Food and Drug Administration-approved, peripherally acting preventive migraine drug capable of inhibiting meningeal nociceptors. Expanding our view of how else this neurotoxin attenuates the activation of the meningeal nociceptors, we reasoned that if the stimulus that triggers the activation of the nociceptor is lessened, the magnitude and/or duration of the nociceptors' activation could diminish as well. In the current study, we further examine this possibility using electrocorticogram recording techniques, immunohistochemistry, and 2-photon microscopy. We report (1) that scalp (head) but not lumbar (back) injections of BoNT-A shorten the period of profound depression of spontaneous cortical activity that follows a pinprick-induced cortical spreading depression (CSD); (2) that neither scalp nor lumbar injections prevent the induction, occurrence, propagation, or spreading velocity of a single wave of CSD; (3) that cleaved SNAP25—one of the most convincing tools to determine the anatomical targeting of BoNT-A treatment—could easily be detected in pericranial muscles at the injection sites and in nerve fibers of the intracranial dura, but not within any cortical area affected by the CSD; (4) that the absence of cleaved SNAP25 within the cortex and pia is unrelated to whether the blood–brain barrier is intact or compromised; and (5) that BoNT-A does not alter vascular responses to CSD. To the best of our knowledge, this is the first report of peripherally applied BoNT-A's ability to alter a neuronal function along a central nervous system pathway involved in the pathophysiology of migraine.

Chronic Kidney Disease (CKD) and neurodegenerative diseases are aging-related diseases. CKD with declined renal function is associated with an elevation of circulating indoxyl sulfate, a metabolite synthesized by gut microbes. We explored the roles of gut microbial metabolites in linking with Central Nervous System (CNS) diseases by administrating indoxyl sulfate intraperitoneally to male C57BL/6 mice with unilateral nephrectomy. Upon exposure, the accumulation of indoxyl sulfate was noted in the blood, prefrontal cortical tissues, and cerebrospinal fluid. Mice showed behavioral signs of mood disorders and neurodegeneration such as anxiety, depression, and cognitive impairment. Those behavioral changes were accompanied by disturbed neuronal survival, neural stem cell activity, expression of Brain-Derived Neurotrophic Factor, serotonin, corticosterone, and Repressor Element-1 Silencing Transcription Factor, and post-receptor intracellular signaling, as well as upregulated oxidative stress and neuroinflammation. Uremic toxin adsorbent AST-120 improved the above mentioned changes. Intriguingly, intracerebroventricular indoxyl sulfate administration only caused limited alterations in the normal mice and the alterations were reversed by aryl hydrocarbon receptor antagonism. The findings suggest pathogenic roles of indoxyl sulfate in the development of CNS diseases, and highlight gut microbiota as alternative targets for intervention with the aim of slowing down the progression of CKD and decreasing CNS complications.

Adequate cerebral blood flow (CBF) is essential to a healthy central nervous system (CNS). Previous work suggests that CBF differs between men and women, and declines with age and certain pathologies, but a highly controlled systematic study across a wide age range, and incorporating white matter (WM) regions, has not been undertaken. Here, we investigate age- and sex-related differences in CBF in gray matter (GM) and WM regions in a cohort (N = 80) of cognitively unimpaired individuals over a wide age range. In agreement with literature, we find that GM regions exhibited lower CBF with age. In contrast, WM regions exhibited higher CBF with age in various cerebral regions. We attribute this new finding to increased oligodendrocyte metabolism to maintain myelin homeostasis in the setting of increased myelin turnover with age. Further, consistent with prior studies, we found that CBF was higher in women than in men in all brain structures investigated. Our work provides new insights into the effects of age and sex on CBF. In addition, our results provide reference CBF values for the standard ASL protocol recommended by the ISMRM Perfusion Study Group and the European ASL in Dementia consortium. Thus, these results provide a foundation for further investigations of CNS perfusion in a variety of settings, including aging, cerebrovascular diseases, and dementias.

Ataxia‐telangiectasia (A‐T) is a genetic disorder caused by the lack of functional ATM kinase. A‐T is characterized by chronic inflammation, neurodegeneration and premature ageing features that are associated with increased genome instability, nuclear shape alterations, micronuclei accumulation, neuronal defects and premature entry into cellular senescence. The causal relationship between the detrimental inflammatory signature and the neurological deficiencies of A‐T remains elusive. Here, we utilize human pluripotent stem cell‐derived cortical brain organoids to study A‐T neuropathology. Mechanistically, we show that the cGAS‐STING pathway is required for the recognition of micronuclei and induction of a senescence‐associated secretory phenotype (SASP) in A‐T olfactory neurosphere‐derived cells and brain organoids. We further demonstrate that cGAS and STING inhibition effectively suppresses self‐DNA‐triggered SASP expression in A‐T brain organoids, inhibits astrocyte senescence and neurodegeneration, and ameliorates A‐T brain organoid neuropathology. Our study thus reveals that increased cGAS and STING activity is an important contributor to chronic inflammation and premature senescence in the central nervous system of A‐T and constitutes a novel therapeutic target for treating neuropathology in A‐T patients., Aguado et al. show that senescent astrocytes upregulate detrimental pro‐inflammatory SASP factors in a cGAS/STING‐dependant manner that promote accelerated ageing in brain organoids of ataxia‐telangiectasia. Pharmacological interventions in these organoids with cGAS and STING inhibitors reduce astrocyte senescence and the SASP, and consequently, improve neuronal activity and survival.

Microglia are the resident immune cells in the central nervous system and play an essential role in brain homeostasis and neuroprotection in brain diseases. Exosomes are crucial in intercellular communication by transporting bioactive miRNAs. Thus, this study aimed to investigate the function of microglial exosome in the presence of ischemic injury and related mechanism. Oxygen-glucose deprivation (OGD)-treated neurons and transient middle cerebral artery occlusion (TMCAO)-treated mice were applied in this study. Western blotting, RT-PCR, RNA-seq, luciferase reporter assay, transmission electron microscope, nanoparticle tracking analysis, immunohistochemistry, TUNEL and LDH assays, and behavioral assay were applied in mechanistic and functional studies. The results demonstrated that exosomes derived from microglia in M2 phenotype (BV2-Exo) were internalized by neurons and attenuated neuronal apoptosis in response to ischemic injury in vitro and in vivo. BV2-Exo also decreased infarct volume and behavioral deficits in ischemic mice. Exosomal miRNA-137 was upregulated in BV2-Exo and participated in the partial neuroprotective effect of BV2-Exo. Furthermore, Notch1 was a directly targeting gene of exosomal miRNA-137. In conclusion, these results suggest that BV2-Exo alleviates ischemia-reperfusion brain injury through transporting exosomal miRNA-137. This study provides novel insight into microglial exosomes-based therapies for the treatment of ischemic brain injury.

Contradictory data have been reported concerning neuropsychiatric side effects of the first-line antiretroviral drug dolutegravir, which may be partly due to lack of control groups or psychiatric assessment tools. Using validated self-report questionnaires, we compared mood and anxiety (DASS-42), impulsivity (BIS-11), and substance use (MATE-Q) between dolutegravir-treated and dolutegravir-naive people living with HIV (PLHIV). We analyzed 194, mostly male, PLHIV on long-term treatment of whom 82/194 (42.3%) used dolutegravir for a median (IQR) of 280 (258) days. Overall, 51/194 (26.3%) participants reported DASS-42 scores above the normal cut-off, 27/194 (13.5%) were classified as highly impulsive, and 58/194 (29.9%) regularly used recreational drugs. Regular substance use was positively associated with depression (p = 0.012) and stress scores (p = 0.045). We observed no differences between dolutegravir-treated and dolutegravir-naive PLHIV. Our data show that depressed and anxious moods and impulsivity are common in PLHIV and associate with substance use and not with dolutegravir use.

Treatment of central nervous system (CNS) demyelination is greatly hindered by lack of the knowledge regarding to underlying molecular mechanisms as well as therapeutic agents. Here, we report a novel small molecule agent, gastrodin (GAS), which can significantly promote CNS myelination in in vivo mice models. By using high-throughput sequencing analysis, we discover a key long non-coding RNA Gm7237 that can enhance CNS myelination and is up-regulated by GAS. Through using bioinformatic analysis and experimental validations, we further unravel that microRNA-142a (miR-142a) and its target myelin gene regulatory factor (MRF) is under the direct regulation by Gm7237. Finally, we demonstrate that Gm7237/miR-142a/MRF axis is the key pathway involved in CNS myelination mediated by GAS. Overall, our results provide not only a novel agent for therapeutic treatment of CNS demyelination but also a molecular basis responsible for GAS-promoted CNS myelination.

Significance: As one part of the central nervous system, the retina manifests neurovascular defects in Alzheimer’s disease (AD). Quantitative imaging of retinal neurovascular abnormalities may promise a new method for early diagnosis and treatment assessment of AD. Previous imaging studies of transgenic AD mouse models have been limited to the central part of the retina. Given that the pathological hallmarks of AD frequently appear in different peripheral quadrants, a comprehensive regional investigation is needed for a better understanding of the retinal degeneration associated with AD-like pathology. Aim: We aim to demonstrate concurrent optical coherence tomography (OCT) and OCT angiography (OCTA) of retinal neuronal and vascular abnormalities in the 5XFAD mouse model and to investigate region-specific retinal degeneration. Approach: A custom-built OCT system was used for retinal imaging. Retinal thickness, vessel width, and vessel density were quantitatively measured. The artery and vein (AV) were classified for differential AV analysis, and trilaminar vascular plexuses were segmented for depth-resolved density measurement. Results: It was observed that inner and outer retinal thicknesses were explicitly reduced in the dorsal and temporal quadrants, respectively, in 5XFAD mice. A significant arterial narrowing in 5XFAD mice was also observed. Moreover, overall capillary density consistently showed a decreasing trend in 5XFAD mice, but regional specificity was not identified. Conclusions: Quadrant- and layer-specific neurovascular degeneration was observed in 5XFAD mice. Concurrent OCT and OCTA promise a noninvasive method for quantitative monitoring of AD progression and treatment assessment.

Analysis of the angioarchitecture and quantification of the conduit vessels and microvasculature is of paramount importance for understanding the physiological and pathological processes within the central nervous system (CNS). Most of the available in vivo imaging methods lack penetration depth and/or resolution. Some ex vivo methods may provide better resolution, but are mainly destructive, as they are designed for imaging the CNS tissues after their removal from the skull or vertebral column. The removal procedure inevitably alters the in situ relations of the investigated structures and damages the dura mater and leptomeninges. µAngiofil, a polymer-based contrast agent, permits a qualitatively novel postmortem microangio-computed tomography (microangioCT) approach with excellent resolution and, therefore, visualization of the smallest brain capillaries. The datasets obtained empower a rather straightforward quantitative analysis of the vascular tree, including the microvasculature. The µAngiofil has an excellent filling capacity as well as a radio-opacity higher than the one of bone tissue, which allows imaging the cerebral microvasculature even within the intact skull or vertebral column. This permits in situ visualization and thus investigation of the dura mater and leptomeningeal layers as well as their blood supply in their original geometry. Moreover, the methodology introduced here permits correlative approaches, i.e., microangioCT followed by classical histology, immunohistochemistry and even electron microscopy. The experimental approach presented here makes use of common desktop microCT scanners, rendering it a promising everyday tool for the evaluation of the (micro)vasculature of the central nervous system in preclinical and basic research. Electronic supplementary material The online version of this article (10.1007/s00429-020-02158-8) contains supplementary material, which is available to authorized users.

The S100 calcium-binding protein beta subunit (S100B) protein, which mostly exists in the central nervous system, is commonly noted as a marker of neuronal damage. We conducted the first systematic review with meta-analysis to compare peripheral blood S100B levels in individuals with ASD with those in healthy controls. A systematic search was carried out for studies published before May 5, 2020. In total, this meta-analysis involved ten studies with 822 participants and 451 cases. The meta-analysis revealed that individuals with ASD had higher peripheral blood S100B levels than healthy controls [standardized mean difference (SMD) = 0.97, 95% confidence interval (95% CI) = 0.41–1.53; p

Staining mice tissues for β-galactosidase activity is a fundamental tool to detect age- or disease-associated cellular senescence. However, reported analyses of positivity for senescence-associated β-galactosidase activity or for other markers of senescence in post-mitotic cells of healthy murine tissues have been fragmentary or inconclusive. Here, we attempted to independently deepen this knowledge using multiple senescence markers within the same cells of wild type mice entering middle age (9 months of age). A histochemistry protocol for the pH-dependent detection of β-galactosidase activity in several tissues was used. At pH 6, routinely utilized to detect senescence-associated β-galactosidase activity, only specific cellular populations in the mouse body (including Purkinje cells and choroid plexus in the central nervous system) were detected as strongly positive for β-galactosidase activity. These post-mitotic cells were also positive for other established markers of senescence (p16, p21 and DPP4), detected by immunofluorescence, confirming a potential senescent phenotype. These data might contribute to understanding the functional relation between the senescence-associated β-galactosidase activity and senescence markers in post-mitotic cells in absence of disease or advanced aging.

Multiple sclerosis (MS) is a central nervous system inflammatory demyelinating disease and the most common cause of non-traumatic disability in young adults. Despite progress in the treatment of the active relapsing disease, therapeutic options targeting irreversible progressive decline remain limited. Studies using skin fibroblasts derived from patients with neurodegenerative disorders demonstrate that cell stress pathways and bioenergetics are altered when compared to healthy individuals. However, findings in MS skin fibroblasts are limited. Here, we collected skin fibroblasts from 24 healthy control individuals, 30 patients with MS, and ten with amyotrophic lateral sclerosis (ALS) to investigate altered cell stress profiles. We observed endoplasmic reticulum swelling in MS skin fibroblasts, and increased gene expression of cell stress markers including BIP, ATF4, CHOP, GRP94, P53, and P21. When challenged against hydrogen peroxide, MS skin fibroblasts had reduced resiliency compared to ALS and controls. Mitochondrial and glycolytic functions were perturbed in MS skin fibroblasts while exhibiting a significant increase in lactate production over ALS and controls. Our results suggest that MS skin fibroblasts have an underlying stress phenotype, which may be disease specific. Interrogating MS skin fibroblasts may provide patient specific molecular insights and aid in prognosis, diagnosis, and therapeutic testing enhancing individualized medicine.

BACKGROUND AND PURPOSE: Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels are encoded by four genes (HCN1-4) with distinct biophysical properties and functions within the brain. HCN4 channels activate slowly at robust hyperpolarizing potentials, making them more likely to be engaged during hyperexcitable neuronal network activity seen during seizures. HCN4 channels are also highly expressed in thalamic nuclei, a brain region implicated in seizure generalisation. Here we assessed the utility of targeting the HCN4 channel as an anti-seizure strategy using pharmacological and genetic approaches. EXPERIMENTAL APPROACH: The impact of reducing HCN4 channel function on seizure susceptibility and neuronal network excitability was studied using a HCN4 channel preferring blocker (EC18) and a conditional brain specific HCN4 knockout mouse model. KEY RESULTS: EC18 (10mg kg-1 ) and brain-specific HCN4 channel knockout reduced seizure susceptibility and proconvulsant-mediated cortical spiking recorded using electrocorticography, with minimal effects on other mouse behaviours. EC18 (10μM) decreased neuronal network bursting in mouse cortical cultures. Importantly, EC18 was not protective against proconvulsant-mediated seizures in the conditional HCN4 channel knockout mouse and did not reduce bursting behaviour in AAV-HCN4 shRNA infected mouse cortical cultures. CONCLUSIONS AND IMPLICATIONS: These data suggest the HCN4 channel as a potential pharmacologically relevant target for anti-seizure drugs that is likely to have a low side-effect liability in the central nervous system.

Glioma is the most prevalent tumor of the central nervous system. To identify differentially expressed miRNAs (DEMs) in gliomas of different grades, bioinformatics analysis was performed. The DEMs between low-grade gliomas (LGGs) and high-grade gliomas (HGGs) were identified by screening the Gene Expression Omnibus and The Cancer Genome Atlas databases using the LIMMA package. Six overlapping DEMs were identified by comparing LGGs and HGGs. Downregulation of miR-1298-3p correlated with poor overall survival rates in glioma patients. Overexpression of miR-1298-3p induced apoptosis of glioma cells and inhibited glioma cell proliferation, migration, and invasion. The basement membrane protein Nidogen-1 (NID1) was identified as a direct binding target of miR-1298-3p in glioma cells. MiR-1298-3p agonist downregulated the NID1 and vimentin levels, but upregulated the level of E-cadherin in glioma cells. Importantly, overexpression of miR-1298-3p induced apoptosis and reduced tumor growth in a mouse xenograft model of glioma. Our results show that miR-1298-3p functions as a tumor suppressor in glioma cells, and suggest that it might serve as a potential biomarker and therapeutic target in glioma patients.

Thrombopoietin (TPO) is a growth factor for the megakaryocytic/platelet lineage. In this study, we investigated the expression of TPO and its receptor, c-Mpl, in the human central nervous system (CNS) and their roles after a neural insult. Our results demonstrate that both TPO and c-Mpl are expressed in the neurons of the human CNS. TPO was also detected in human cerebrospinal fluid. TPO was found to be neuroprotective in hypoxic-ischemic neonatal rat brain models. In these rat models, treatment with TPO reduced brain damage and improved sensorimotor functions. In addition, TPO promoted C17.2 cell proliferation through activation of the PI3K/Akt signaling pathway. Via the Bcl-2/BAX signaling pathway, TPO exerted an antiapoptotic effect by suppressing mitochondrial membrane potentials. Taken together, our results indicate that TPO is neuroprotective in the CNS.

Current antisense oligonucleotide (ASO) therapies for the treatment of central nervous system (CNS) disorders are performed through invasive administration, thereby placing a major burden on patients. To alleviate this burden, we herein report systemic ASO delivery to the brain by crossing the blood–brain barrier using glycemic control as an external trigger. Glucose‐coated polymeric nanocarriers, which can be bound by glucose transporter‐1 expressed on the brain capillary endothelial cells, are designed for stable encapsulation of ASOs, with a particle size of about 45 nm and an adequate glucose‐ligand density. The optimized nanocarrier efficiently accumulates in the brain tissue 1 h after intravenous administration and exhibits significant knockdown of a target long non‐coding RNA in various brain regions, including the cerebral cortex and hippocampus. These results demonstrate that the glucose‐modified polymeric nanocarriers enable noninvasive ASO administration to the brain for the treatment of CNS disorders., The sweet spot: Antisense‐oligonucleotide‐loaded glucosylated‐polyion‐complex micelles can be used for RNA knockdown in various brain regions using blood‐glucose level as an external trigger. Glucose transporter‐1 expressed on the brain capillary endothelial cells binds the glucose‐coated nanocarrier and transports it, along with its cargo, across the blood–brain barrier. This could be used for the treatment of disorders of the central nervous system.

PAC1 receptor blockade using a monoclonal antibody inhibits nociceptive neuronal activity in the trigeminocervical complex., Pituitary adenylate cyclase activating polypeptide-38 (PACAP38) may play an important role in primary headaches. Preclinical evidence suggests that PACAP38 modulates trigeminal nociceptive activity mainly through PAC1 receptors while clinical studies report that plasma concentrations of PACAP38 are elevated in spontaneous attacks of cluster headache and migraine and normalize after treatment with sumatriptan. Intravenous infusion of PACAP38 induces migraine-like attacks in migraineurs and cluster-like attacks in cluster headache patients. A rodent-specific PAC1 receptor antibody Ab181 was developed, and its effect on nociceptive neuronal activity in the trigeminocervical complex was investigated in vivo in an electrophysiological model relevant to primary headaches. Ab181 is potent and selective at the rat PAC1 receptor and provides near-maximum target coverage at 10 mg/kg for more than 48 hours. Without affecting spontaneous neuronal activity, Ab181 effectively inhibits stimulus-evoked activity in the trigeminocervical complex. Immunohistochemical analysis revealed its binding in the trigeminal ganglion and sphenopalatine ganglion but not within the central nervous system suggesting a peripheral site of action. The pharmacological approach using a specific PAC1 receptor antibody could provide a novel mechanism with a potential clinical efficacy in the treatment of primary headaches.

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterized by abnormal accumulation of alpha-synuclein (α-syn) in oligodendrocytes accompanied by inflammation, demyelination, and subsequent synapse and neuronal loss. Little is known about the mechanisms of neurodegeneration in MSA. However, recent work has highlighted the important role of the immune system to the pathophysiology of other synuclein-related diseases such as Parkinson’s disease. In this study, we investigated postmortem brain tissue from MSA patients and control subjects for evidence of immune activation in the brain. We found a significant increase of HLA-DR+ microglia in the putamen and substantia nigra of MSA patient tissue compared to controls, as well as significant increases in CD3+, CD4+, and CD8+ T cells in these same brain regions. To model MSA in vivo, we utilized a viral vector that selectively overexpresses α-syn in oligodendrocytes (Olig001-SYN) with > 95% tropism in the dorsal striatum of mice, resulting in demyelination and neuroinflammation similar to that observed in human MSA. Oligodendrocyte transduction with this vector resulted in a robust inflammatory response, which included increased MHCII expression on central nervous system (CNS) resident microglia, and infiltration of pro-inflammatory monocytes into the CNS. We also observed robust infiltration of CD4 T cells into the CNS and antigen-experienced CD4 T cells in the draining cervical lymph nodes. Importantly, genetic deletion of TCR-β or CD4 T cells attenuated α-syn-induced inflammation and demyelination in vivo. These results suggest that T cell priming and infiltration into the CNS are key mechanisms of disease pathogenesis in MSA, and therapeutics targeting T cells may be disease modifying. Electronic supplementary material The online version of this article (10.1007/s00401-020-02126-w) contains supplementary material, which is available to authorized users.

Oligodendrocytes (OLs) generate myelin membranes for the rapid propagation of electrical signals along axons in the central nervous system (CNS) and provide metabolites to support axonal integrity and function. Differentiation of OLs from oligodendrocyte progenitor cells (OPCs) is orchestrated by a multitude of intrinsic and extrinsic factors in the CNS. Disruption of this process, or OL loss in the developing or adult brain, as observed in various neurological conditions including hypoxia/ischemia, stroke, and demyelination, results in axonal dystrophy, neuronal dysfunction, and severe neurological impairments. While much is known regarding the intrinsic regulatory signals required for OL lineage cell progression in development, studies from pathological conditions highlight the importance of the CNS environment and external signals in regulating OL genesis and maturation. Here, we review the recent findings in OL biology in the context of the CNS physiological and pathological conditions, focusing on extrinsic factors that facilitate OL development and regeneration.

Astrocytes are well known to play critical roles in the development and maintenance of the central nervous system (CNS). Moreover, recent reports indicate that these cells are heterogeneous with respect to the molecules they express and the functions they exhibit in the quiescent or activated state. Because astrocytes also contribute to pathology, promising new results raise the possibility of manipulating specific astroglial populations for therapeutic roles. In this mini-review, we highlight the function of metabotropic glutamate receptors (mGluRs), in particular mGluR3 and mGluR5, in reactive astrocytes and relate these to three degenerative CNS diseases: multiple sclerosis, Alzheimer’s disease and Amyotrophic Lateral Sclerosis. Previous studies demonstrate that effects of these receptors may be beneficial, but this varies depending on the subtype of receptor, the state of the astrocytes, and the specific disease to which they are exposed. Elucidating the role of mGluRs on astrocytes at specific times during development and disease will provide novel insights in understanding how to best use these to serve as therapeutic targets.

Significance: Whether or not capillary pericytes contribute to blood flow regulation in the brain and retina has long been debated. This was partly caused by failure of detecting the contractile protein α-smooth muscle actin (α-SMA) in capillary pericytes. Aim: The aim of this review is to summarize recent developments in detecting α-SMA and contractility in capillary pericytes and the relevant literature on the biology of actin filaments. Results: Evidence suggests that for visualization of the small amounts of α-SMA in downstream mid-capillary pericytes, actin depolymerization must be prevented during tissue processing. Actin filaments turnover is mainly based on de/re-polymerization rather than transcription of the monomeric form, hence, small amounts of α-SMA mRNA may evade detection by transcriptomic studies. Similarly, transgenic mice expressing fluorescent reporters under the α-SMA promoter may yield low fluorescence due to limited transcriptional activity in mid-capillary pericytes. Recent studies show that pericytes including mid-capillary ones express several actin isoforms and myosin heavy chain type 11, the partner of α-SMA in mediating contraction. Emerging evidence also suggests that actin polymerization in pericytes may have a role in regulating the tone of downstream capillaries. Conclusions: With guidance of actin biology, innovative labeling and imaging techniques can reveal the molecular machinery of contraction in pericytes.

In patients with osteoarthritis undergoing total hip arthroplasty, higher cerebrospinal fluid concentrations of serotonin and dopamine metabolites are associated with increased pain severity and central sensitization., Introduction: Monoaminergic activity modulates nociceptive transmission in the central nervous system (CNS). Although pain is the most disabling symptom of osteoarthritis (OA), limited knowledge exists regarding the CNS mechanisms that amplify pain and drive sensitization processes in humans. Objectives: The main objective of this study was to evaluate associations between cerebrospinal fluid (CSF) monoamine metabolites, pain severity, and central sensitization in patients with OA undergoing total hip arthroplasty (THA). Methods: Patients with OA (n = 52) and pain-free controls (n = 30) provided CSF samples for measurement of serotonin (5-hydroxyindoleacetic acid [5-HIAA]), noradrenaline (3-methoxy-4-hydroxyphenylglycol [HMPG]), and dopamine (homovanillic acid [HVA]) monoamine metabolites. Patients with OA completed longitudinal evaluation of pain using clinical measures and quantitative sensory testing. Results: Patients with OA had higher HMPG levels when compared with controls (P = 0.036). Within patients with OA undergoing THA, higher 5-HIAA and HVA levels were consistently associated with higher preoperative pain severity. Higher concentrations of 5-HIAA and HVA were also associated with lower conditioned pain modulation levels, whereas higher HMPG levels were linked to more efficient conditioned pain modulation. Patients with higher levels of CSF HVA exhibited increased pressure pain sensitivity (arm pressure pain detection threshold < 250 kPa vs ≥ 250 kPa, P = 0.042). Higher preoperative levels of CSF 5-HIAA predicted poorer pain control 6 months postoperatively (brief pain inventory pain severity; adjusted β = 0.010, 95% CI 0.001–0.019). Conclusions: In OA patients with disabling pain, higher CSF levels of serotonin and dopamine metabolites are associated with increased pain severity and central sensitization. Increased noradrenergic activity may be associated with more efficient pain inhibitory capacity.

Despite current central nervous system‐directed therapies for childhood B‐cell precursor acute lymphoblastic leukaemia, relapse at this anatomical site still remains a challenging issue. Few reports have addressed the study of the specific cellular microenvironments which can promote the survival, quiescence, and therefore chemoresistance of B‐cell precursor acute lymphoblastic leukaemia cells in the central nervous system. Herein, we showed by immunofluorescence and electron microscopy that in xenotransplanted mice, leukaemic cells infiltrate the connective tissue stroma of the choroid plexus, the brain structure responsible for the production of cerebrospinal fluid. The ultrastructural study also showed that leukaemia cells are able to migrate through blood vessels located in the choroid plexus stroma. In short‐term co‐cultures, leukaemic cells established strong interactions with human choroid plexus fibroblasts, mediated by an increased expression of ITGA4 (VLA‐4)/ITGAL (LFA‐1) and their ligands VCAM1/ICAM1. Upon contact with leukaemia cells, human choroid plexus fibroblasts acquired a cancer‐associated fibroblast phenotype, with an increased expression of α‐SMA and vimentin as well as pro‐inflammatory factors. Human choroid plexus fibroblasts also have the capacity to reduce the proliferative index of leukaemic blasts and promote their survival and chemoresistance to methotrexate and cytarabine. The inhibition of VLA‐4/VCAM‐1 interactions using anti‐VLA‐4 antibodies, and the blockade of Notch signalling pathway by using a γ‐secretase inhibitor partially restored chemotherapy sensitivity of leukaemia cells. We propose that the choroid plexus stroma constitutes a sanctuary for B‐cell precursor acute lymphoblastic leukaemia cells in the central nervous system. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Hypoxia caused by ischemia induces acidosis and neuroexcitotoxicity, resulting in neuronal death in the central nervous system (CNS). Monoacylglycerol lipase (MAGL) is a modulator of 2-arachidonoylglycerol (2-AG), which is involved in retrograde inhibition of glutamate release in the endocannabinoid system. In the present study, we used positron emission tomography (PET) to monitor MAGL-positive neurons and neuroinflammation in the brains of ischemic rats. Additionally, we performed PET imaging to evaluate the neuroprotective effects of an MAGL inhibitor in an ischemic injury model. Methods: Ischemic-injury rat models were induced by intraluminal right middle cerebral artery occlusion (MCAO). PET studies of the brains of the ischemic rats were performed at several experimental time points (pre-occlusion, days 2, 4, and 7 after the MCAO surgery) using [11C]SAR127303 for MAGL and [18F]FEBMP for 18 kDa translocator protein (TSPO, a hall-mark of neuroinflammation). Medication using minocycline (a well-known neuroprotective agent) or KML29 (a potent MAGL inhibitor) was given immediately after the MCAO surgery and then daily over the subsequent three days. Results: PET imaging of the ischemic rats using [11C]SAR127303 showed an acute decline of radioactive accumulation in the ipsilateral side at two days after MCAO surgery (ratio of the area under the curve between the ipsilateral and contralateral sides: 0.49 ± 0.04 in the cortex and 0.73 ± 0.02 in the striatum). PET imaging with [18F]FEBMP, however, showed a moderate increase in accumulation of radioactivity in the ipsilateral hemisphere on day 2 (1.36 ± 0.11), and further increases on day 4 (1.72 ± 0.15) and day 7 (1.99 ± 0.06). Treatment with minocycline or KML29 eased the decline in radioactive accumulation of [11C]SAR127303 for MAGL (minocycline-treated group: 0.82 ± 0.06 in the cortex and 0.81 ± 0.05 in the striatum; KML29-treated group: 0.72 ± 0.07 in the cortex and 0.88 ± 0.04 in the striatum) and increased uptake of [18F]FEBMP for TSPO (minocycline-treated group: 1.52 ± 0.21 in the cortex and 1.56 ± 0.11 in the striatum; KML29-treated group: 1.63 ± 0.09 in the cortex and 1.50 ± 0.17 in the striatum). In MCAO rats, minocycline treatment showed a neuroprotective effect in the sensorimotor cortex suffering from severe hypoxic injury, whereas KML29 treatment saved neurons in the striatum, including bundles of myelinated axons. Conclusions: PET imaging allowed visualization of the different neuroprotective effects of minocycline and KML29, and indicated that combination pharmacotherapy using these drugs may be an effective therapy in acute ischemia.

Joubert syndrome (JS) is a ciliopathy associated with mutations in numerous genes encoding cilia components. TALPID3 encoded by KIAA0856 in man (2700049A03Rik in mouse) is a centrosomal protein essential for the assembly of primary cilia. Mutations in KIAA0856 have been recently identified in JS patients. Herein, we describe a novel mouse JS model with a conditional deletion of the conserved exons 11–12 of Talpid3 in the central nervous system which recapitulates the complete cerebellar phenotype seen in JS. Talpid3 mutant mice exhibit key hallmarks of JS including progressive ataxia, severely hypoplastic cerebellar hemispheres and vermis, together with abnormal decussation of the superior cerebellar peduncles. The Purkinje cell layer is disorganised with abnormal dendritic arborisation. The external granule layer (EGL) is thinner, lacks primary cilia, and has a reduced level of proliferation. Furthermore, we describe novel cellular defects including ectopic clusters of mature granule neurons, and abnormal parallel fibre‐derived synapses and disorientation of cells in the EGL. The defective glial scaffold results in abnormal granule cell migration which manifests as ectopic clusters of granule neurons. In addition, we show a reduction in Wnt7a expression suggesting that defects may arise not only from deficiencies in the Hedgehog (Hh) pathway but also due to the additional roles of Talpid3. The Talpid3 conditional knockout mouse is a novel JS model which fully recapitulates the JS cerebellar phenotype. These findings reveal a role for Talpid3 in granule precursor cell migration in the cerebellum (either direct or indirect) which together with defective Hh signalling underlies the JS phenotype. Our findings also illustrate the utility of creating conditional mouse models to assist in unravelling the molecular and cellular mechanisms underlying JS. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

The outcomes of intensity-modulated proton craniospinal irradiation (ipCSI) are unclear. We evaluated the clinical benefit of our newly developed ipCSI system that incorporates two gantry-mounted orthogonal online X-ray imagers with a robotic six-degrees-of-freedom patient table. Nine patients (7–19 years old) were treated with ipCSI. The prescribed dose for CSI ranged from 23.4 to 36.0 Gy (relative biological effectiveness) in 13–20 fractions. Four adolescent and young adult (AYA) patients (15 years or older) were treated with vertebral-body-sparing ipCSI (VBSipCSI). Myelosuppression following VBSipCSI was compared with that of eight AYA patients treated with photon CSI at the same institution previously. The mean homogeneity index (HI) in the nine patients was 0.056 (95% confidence interval: 0.044–0.068). The mean time from the start to the end of all beam delivery was 37 min 39 s ± 2 min 24 s (minimum to maximum: 22 min 49 s – 42 min 51 s). The nadir white blood cell, hemoglobin, and platelet levels during the 4 weeks following the end of the CSI were significantly higher in the VBSipCSI group than in the photon CSI group (P = 0.0071, 0.0453, 0.0024, respectively). The levels at 4 weeks after the end of CSI were significantly higher in the VBSipCSI group than in the photon CSI group (P = 0.0023, 0.0414, 0.0061). Image-guided ipCSI was deliverable in a reasonable time with sufficient HI. Using VBSipCSI, AYA patients experienced a lower incidence of serious acute hematological toxicity than AYA patients treated with photon CSI.

Purpose Leukoaraiosis (LA), according to the latest classification, is white matter hyperintensity - morphological findings of small blood vessel disease of the brain. This radiological detection of small vessels disease is important because there are no technical possibilities to assess small vessels of the brain using computed tomography (CT) or magnetic resonance imaging (MRI) angiography. Our aim was to analysis the relationship between the extension of leukoaraiosis and severity of ischaemic stroke and brain atrophy. Material and methods We retrospectively analysed 77 head CT scans of patients admitted from the emergency room (ER) to the Radiology Department due to suspected stroke. We assessed the severity of leukoaraiosis using the van Swieten scale and brain atrophy by numerous linear measurements. Results Statistical analysis failed to demonstrate differences between LA1 and LA2 groups with regard to stroke severity in National Institutes of Health Stroke Scale (NIHSS) (p = 0.2159). There were no differences with regard to clinical severity of stroke between the study groups divided depending on the extent of brain atrophy. There were statistically significant differences with regard to the anterior horn width of the right and left lateral ventricle, posterior horn width of the right and left lateral ventricle, distance between occipital horn of the left lateral ventricle and internal surface of the cranium and third ventricle width depending on the severity of leukoaraiosis. Conclusions The results of our studies present an association between the degree leukoaraiosis extension and brain atrophy, but no association between central nervous system tissue atrophy of extent of leukoaraiosis and ischaemic stroke severity.

Copper (Cu) is a vital trace element that acts as a cofactor of proteins and enzymes in many molecular pathways including the central nervous system. The accumulation or deficiency of copper could alter neuronal function and lead to neuronal degeneration and brain dysfunction. Intake of high levels of copper can also cause copper toxicosis that affects the brain structure and function. Despite clinical and experimental data indicating the association between abnormal copper homeostasis and brain dysfunction, the effects of copper on cerebellum have remained poorly understood. Hence, this study aimed to evaluate the effects of copper sulfate on the cerebellum via stereological and behavioral methods in rats. Male rats (Sprague-Dawley) were divided to three groups. The rats in the control group orally received distilled water, while those in the Cu groups received 1 mM (159 mg/L) or 8 mM (1272 mg/L) copper sulfate by oral gavage solved in distilled water daily for 4 weeks. Then, the rotarod performance test was recorded and the cerebellum was prepared for stereological assessments. The Cu-administered rats (1 and 8 mM) exhibited a significant reduction in the total volumes of the cerebellum structures. The total number of the cells in the cerebellar cortex and deep cerebellar nuclei were significantly decreased via Cu in a dose-dependent manner. Furthermore, the length of nerve fibers and the number of spines per nerve fiber decreased significantly in the Cu groups. These changes were correlated to the animals’ motor performance impairment in the rotarod test. The findings suggested that copper toxicity induced motor performance impairments in the rats, which could be attributed to its deleterious effects on the cerebellum structure., Highlights • Copper decreased the cell number and total volume of the cerebellum. • Copper decreased the length of the nerve fibers and dendritic spines. • The motor performance change correlates with the structural change in the cerebellum by copper.

Serotonin 6 receptor (5‐HT6R) is a promising target for a variety of human diseases, such as Alzheimer's disease (AD) and schizophrenia. However, the detailed mechanism underlying 5‐HT6R activity in the central nervous system (CNS) is not fully understood. In the present study, 5‐HT6R null mutant (5‐HT6R−/−) mice were found to exhibit cognitive deficiencies and abnormal anxiety levels. 5‐HT6R is considered to be specifically localized on the primary cilia. We found that the loss of 5‐HT6R affected the Sonic Hedgehog signaling pathway in the primary cilia. 5‐HT6R−/− mice showed remarkable alterations in neuronal morphology, including dendrite complexity and axon initial segment morphology. Neurons lacking 5‐HT6R exhibited increased neuronal excitability. Our findings highlight the complexity of 5‐HT6R functions in the primary ciliary and neuronal physiology, supporting the theory that this receptor modulates neuronal morphology and transmission, and contributes to cognitive deficits in a variety of human diseases, such as AD, schizophrenia, and ciliopathies., Alzheimer’s disease (AD) is associated with changesin synaptic morphology, nervous system dysfunction, and cognitive decline. Lossof 5‐HT6R elevates anxiety and decreases learning and memory ability in mice.Meanwhile, changes in ciliary signaling, dendrites, synaptic plasticity, andneuronal excitability are found in 5‐HT6R mutant mice, suggesting that5‐HT6R has potential therapeutic value in impeding AD progression.

Although all cells contain iron, most histochemical methods fail to reveal the presence of iron within many cells of the central nervous system (CNS), particularly neurons. Previously, a sensitive method was developed that limited the extraction of iron in paraffin sections, and this method revealed staining within neurons. However, the staining was often too robust making it difficult to discern discrete intracellular structures. In 1970, a study incorporated acetone in an iron histochemical procedure to facilitate the demarcation of staining features. In the present study, both acetone and limits to iron extraction were included in a simplified staining procedure. This procedure was applied to paraffin sections of CNS tissue from CISD2 deficient and littermate control mice. Discrete nuclear and cytoplasmic staining features were detected in all mice. Although widely present in neurons, punctate cytoplasmic staining was particularly prominent in large neurons within the hindbrain. Evaluation of extended depth of focus images, from serial focal planes, revealed numerous stained cytoplasmic structures. Additionally, the simplified staining procedure was applied to paraffin sections from Alzheimer’s disease and control cases. Despite suboptimal processing conditions compared to mouse tissue, discrete staining of cytoplasmic structures was revealed in some neurons, although many other neurons had nondescript staining features. In addition, initial findings revealed iron deposited within some vessels from patients with Alzheimer’s disease. In summary, since paraffin sections are commonly used for histological preparations, this simplified histochemical procedure could facilitate the study of iron in various CNS conditions by revealing staining details often missed by other procedures.