Early High-Titer Plasma Therapy to Prevent Severe Covid-19 in Older Adults.

BACKGROUND: Therapies to interrupt the progression of early coronavirus disease 2019 (Covid-19) remain elusive. Among them, convalescent plasma administered to hospitalized patients has been unsuccessful, perhaps because antibodies should be administered earlier in the course of illness. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of convalescent plasma with high IgG titers against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in older adult patients within 72 hours after the onset of mild Covid-19 symptoms. The primary end point was severe respiratory disease, defined as a respiratory rate of 30 breaths per minute or more, an oxygen saturation of less than 93% while the patient was breathing ambient air, or both. The trial was stopped early at 76% of its projected sample size because cases of Covid-19 in the trial region decreased considerably and steady enrollment of trial patients became virtually impossible. RESULTS: A total of 160 patients underwent randomization. In the intention-to-treat population, severe respiratory disease developed in 13 of 80 patients (16%) who received convalescent plasma and 25 of 80 patients (31%) who received placebo (relative risk, 0.52; 95% confidence interval [CI], 0.29 to 0.94; P = 0.03), with a relative risk reduction of 48%. A modified intention-to-treat analysis that excluded 6 patients who had a primary end-point event before infusion of convalescent plasma or placebo showed a larger effect size (relative risk, 0.40; 95% CI, 0.20 to 0.81). No solicited adverse events were observed. CONCLUSIONS: Early administration of high-titer convalescent plasma against SARS-CoV-2 to mildly ill infected older adults reduced the progression of Covid-19. (Funded by the Bill and Melinda Gates Foundation and the Fundación INFANT Pandemic Fund; Dirección de Sangre y Medicina Transfusional del Ministerio de Salud number, PAEPCC19, Plataforma de Registro Informatizado de Investigaciones en Salud number, 1421, and ClinicalTrials.gov number, NCT04479163.).

Neurogenesis of medium spiny neurons in the nucleus accumbens continues into adulthood and is enhanced by pathological pain.

In mammals, most adult neural stem cells (NSCs) are located in the ventricular-subventricular zone (V-SVZ) along the wall of the lateral ventricles and they are the source of olfactory bulb interneurons. Adult NSCs exhibit an apico-basal polarity; they harbor a short apical process and a long basal process, reminiscent of radial glia morphology. In the adult mouse brain, we detected extremely long radial glia-like fibers that originate from the anterior-ventral V-SVZ and that are directed to the ventral striatum. Interestingly, a fraction of adult V-SVZ-derived neuroblasts dispersed in close association with the radial glia-like fibers in the nucleus accumbens (NAc). Using several in vivo mouse models, we show that newborn neurons integrate into preexisting circuits in the NAc where they mature as medium spiny neurons (MSNs), i.e., a type of projection neurons formerly believed to be generated only during embryonic development. Moreover, we found that the number of newborn neurons in the NAc is dynamically regulated by persistent pain, suggesting that adult neurogenesis of MSNs is an experience-modulated process.

Neuronal signatures in cancer.

Despite advances in the treatment of solid tumors, the prognosis of patients with many cancers remains poor, particularly of those with primary and metastatic brain tumors. In the last years, "Cancer Neuroscience" emerged as novel field of research at the crossroads of oncology and classical neuroscience. In primary brain tumors, including glioblastoma (GB), communicating networks that render tumor cells resistant against cytotoxic therapies were identified. To build these networks, GB cells extend neurite-like protrusions called tumor microtubes (TMs). Synapses on TMs allow tumor cells to retrieve neuronal input that fosters growth. Single cell sequencing further revealed that primary brain tumors recapitulate many steps of neurodevelopment. Interestingly, neuronal characteristics, including the ability to extend neurite-like protrusions, neuronal gene expression signatures and interactions with neurons, have now been found not only in brain and neuroendocrine tumors but also in some cancers of epithelial origin. In this review, we will provide an overview about neurite-like protrusions as well as neurodevelopmental origins, hierarchies and gene expression signatures in cancer. We will also discuss how "Cancer Neuroscience" might provide a framework for the development of novel therapies.

Experimental Cerebral Malaria Spreads along the Rostral Migratory Stream.

It is poorly understood how progressive brain swelling in experimental cerebral malaria (ECM) evolves in space and over time, and whether mechanisms of inflammation or microvascular sequestration/obstruction dominate the underlying pathophysiology. We therefore monitored in the Plasmodium berghei ANKA-C57BL/6 murine ECM model, disease manifestation and progression clinically, assessed by the Rapid-Murine-Coma-and-Behavioral-Scale (RMCBS), and by high-resolution in vivo MRI, including sensitive assessment of early blood-brain-barrier-disruption (BBBD), brain edema and microvascular pathology. For histological correlation HE and immunohistochemical staining for microglia and neuroblasts were obtained. Our results demonstrate that BBBD and edema initiated in the olfactory bulb (OB) and spread along the rostral-migratory-stream (RMS) to the subventricular zone of the lateral ventricles, the dorsal-migratory-stream (DMS), and finally to the external capsule (EC) and brainstem (BS). Before clinical symptoms (mean RMCBS = 18.5±1) became evident, a slight, non-significant increase of quantitative T2 and ADC values was observed in OB+RMS. With clinical manifestation (mean RMCBS = 14.2±0.4), T2 and ADC values significantly increased along the OB+RMS (p = 0.049/p = 0.01). Severe ECM (mean RMCBS = 5±2.9) was defined by further spread into more posterior and deeper brain structures until reaching the BS (significant T2 elevation in DMS+EC+BS (p = 0.034)). Quantitative automated histological analyses confirmed microglial activation in areas of BBBD and edema. Activated microglia were closely associated with the RMS and neuroblasts within the RMS were severely misaligned with respect to their physiological linear migration pattern. Microvascular pathology and ischemic brain injury occurred only secondarily, after vasogenic edema formation and were both associated less with clinical severity and the temporal course of ECM. Altogether, we identified a distinct spatiotemporal pattern of microglial activation in ECM involving primarily the OB+RMS axis, a distinct pathway utilized by neuroblasts and immune cells. Our data suggest significant crosstalk between these two cell populations to be operative in deeper brain infiltration and further imply that the manifestation and progression of cerebral malaria may depend on brain areas otherwise serving neurogenesis.

Downregulation of Sphingosine 1-Phosphate Receptor 1 Promotes the Switch from Tangential to Radial Migration in the OB.

Neuroblast migration is a highly orchestrated process that ensures the proper integration of newborn neurons into complex neuronal circuits. In the postnatal rodent brain, neuroblasts migrate long distances from the subependymal zone of the lateral ventricles to the olfactory bulb (OB) within the rostral migratory stream (RMS). They first migrate tangentially in close contact to each other and later radially as single cells until they reach their final destination in the OB. Sphingosine 1-phosphate (S1P) is a bioactive lipid that interacts with cell-surface receptors to exert different cellular responses. Although well studied in other systems and a target for the treatment of multiple sclerosis, little is known about S1P in the postnatal brain. Here, we report that the S1P receptor 1 (S1P1) is expressed in neuroblasts migrating in the RMS. Using in vivo and in vitro gain- and loss-of-function approaches in both wild-type and transgenic mice, we found that the activation of S1P1 by its natural ligand S1P, acting as a paracrine signal, contributes to maintain neuroblasts attached to each other while they migrate in chains within the RMS. Once in the OB, neuroblasts cease to express S1P1, which results in cell detachment and initiation of radial migration, likely via downregulation of NCAM1 and ß1 integrin. Our results reveal a novel physiological function for S1P1 in the postnatal brain, directing the path followed by newborn neurons in the neurogenic niche. SIGNIFICANCE STATEMENT: The function of each neuron is highly determined by the position it occupies within a neuronal circuit. Frequently, newborn neurons must travel long distances from their birthplace to their predetermined final location and, to do so, they use different modes of migration. In this study, we identify the sphingosine 1-phosphate (S1P) receptor 1 (S1P1) as one of the key players that govern the switch from tangential to radial migration of postnatally generated neuroblasts in the olfactory bulb. Of interest is the evidence that the ligand, S1P, is provided by nearby astrocytes. Finally, we also propose adhesion molecules that act downstream of S1P1 and initiate the transition from tangential chain migration to individual radial migration outside of the stream.

Developmental signals control chromosome segregation fidelity during pluripotency and neurogenesis by modulating replicative stress.

Human development relies on the correct replication, maintenance and segregation of our genetic blueprints. How these processes are monitored across embryonic lineages, and why genomic mosaicism varies during development remain unknown. Using pluripotent stem cells, we identify that several patterning signals-including WNT, BMP, and FGF-converge into the modulation of DNA replication stress and damage during S-phase, which in turn controls chromosome segregation fidelity in mitosis. We show that the WNT and BMP signals protect from excessive origin firing, DNA damage and chromosome missegregation derived from stalled forks in pluripotency. Cell signalling control of chromosome segregation declines during lineage specification into the three germ layers, but re-emerges in neural progenitors. In particular, we find that the neurogenic factor FGF2 induces DNA replication stress-mediated chromosome missegregation during the onset of neurogenesis, which could provide a rationale for the elevated chromosomal mosaicism of the developing brain. Our results highlight roles for morphogens and cellular identity in genome maintenance that contribute to somatic mosaicism during mammalian development.

Proinflammatory immune cells disrupt angiogenesis and promote germinal matrix hemorrhage in prenatal human brain.

Germinal matrix hemorrhage (GMH) is a devastating neurodevelopmental condition affecting preterm infants, but why blood vessels in this brain region are vulnerable to rupture remains unknown. Here we show that microglia in prenatal mouse and human brain interact with nascent vasculature in an age-dependent manner and that ablation of these cells in mice reduces angiogenesis in the ganglionic eminences, which correspond to the human germinal matrix. Consistent with these findings, single-cell transcriptomics and flow cytometry show that distinct subsets of CD45+ cells from control preterm infants employ diverse signaling mechanisms to promote vascular network formation. In contrast, CD45+ cells from infants with GMH harbor activated neutrophils and monocytes that produce proinflammatory factors, including azurocidin 1, elastase and CXCL16, to disrupt vascular integrity and cause hemorrhage in ganglionic eminences. These results underscore the brain's innate immune cells in region-specific angiogenesis and how aberrant activation of these immune cells promotes GMH in preterm infants.

Subventricular zone-derived neuroblasts use vasculature as a scaffold to migrate radially to the cortex in neonatal mice.

Neurons continue to be generated in the subventricular zone (SVZ) throughout postnatal development and adulthood in rodents. Whereas in adults, virtually all neuroblasts migrate tangentially to the olfactory bulb via the rostral migratory stream (RMS), in neonates, a substantial fraction migrate radially through the corpus callosum (CC) to the cortex. Mechanisms of radial cortical migration have remained unknown. We investigated this by taking recourse to enhanced green fluorescent protein (EGFP)-labeled neuroblasts in the CC and deep cortical layers of neonatal mice and found that they are frequently located adjacent to vasculature. Using time-lapse 2-photon microscopy in acute brain slices, we demonstrate that EGFP-labeled neuroblasts migrate along blood vessels. Although in close proximity to blood vessels, migrating neuroblasts are separated from endothelial cells by 1-2 layers of astrocytic processes, as revealed by electron microscopal studies of retrovirally labeled postnatally born cells. We propose that 2 factors could contribute to the decline of radial migration to the cortex during postnatal development, namely the establishment of a glial sheath delineating the RMS and a gradual decrease in the density of blood vessels in the CC. Together, our data provide evidence for a new mode of radial cortical migration of SVZ-generated neurons involving vasculature and astrocytes.

Spatial transcriptomics map of the embryonic mouse brain - a tool to explore neurogenesis.

The developing brain has a well-organized anatomical structure comprising different types of neural and non-neural cells. Stem cells, progenitors and newborn neurons tightly interact with their neighbouring cells and tissue microenvironment, and this intricate interplay ultimately shapes the output of neurogenesis. Given the relevance of spatial cues during brain development, we acknowledge the necessity for a spatial transcriptomics map accessible to the neurodevelopmental community. To fulfil this need, we generated spatially resolved RNA sequencing (RNAseq) data from embryonic day 13.5 mouse brain sections immunostained for mitotic active neural and vascular cells. Unsupervised clustering defined specific cell type populations of diverse lineages and differentiation states. Differential expression analysis revealed unique transcriptional signatures across specific brain areas, uncovering novel features inherent to particular anatomical domains. Finally, we integrated existing single-cell RNAseq datasets into our spatial transcriptomics map, adding tissue context to single-cell RNAseq data. In summary, we provide a valuable tool that enables the exploration and discovery of unforeseen molecular players involved in neurogenesis, particularly in the crosstalk between different cell types.

Targeting fatty acid oxidation via Acyl-CoA binding protein hinders glioblastoma invasion.

The diffuse nature of Glioblastoma (GBM) tumors poses a challenge to current therapeutic options. We have previously shown that Acyl-CoA Binding Protein (ACBP, also known as DBI) regulates lipid metabolism in GBM cells, favoring fatty acid oxidation (FAO). Here we show that ACBP downregulation results in wide transcriptional changes affecting invasion-related genes. In vivo experiments using patient-derived xenografts combined with in vitro models demonstrated that ACBP sustains GBM invasion via binding to fatty acyl-CoAs. Blocking FAO mimics ACBPKD-induced immobility, a cellular phenotype that can be rescued by increasing FAO rates. Further investigation into ACBP-downstream pathways served to identify Integrin beta-1, a gene downregulated upon inhibition of either ACBP expression or FAO rates, as a mediator for ACBP's role in GBM invasion. Altogether, our findings highlight a role for FAO in GBM invasion and reveal ACBP as a therapeutic vulnerability to stall FAO and subsequent cell invasion in GBM tumors.

"Small axonless neurons": postnatally generated neocortical interneurons with delayed functional maturation.

GABAergic interneurons of the mouse cortex are generated embryonically in the ventral telencephalon. Recent evidence, however, indicated that a subset of cortical cells expressing interneuronal markers originate in the neonatal subventricular zone. This has raised interest in the functional development and incorporation of these postnatally generated cells into cortical circuits. Here we demonstrate that these cells integrate in the cortex, and that they constitute two distinct GABAergic interneuronal classes. Whereas one class reflects the tail end of embryonic interneuron genesis, the other class comprises interneurons that are exclusively generated perinatally and postnatally. The latter constitute a novel subclass of interneurons. They are preferentially located in the deeper layers of the olfactory and orbital cortices, exhibit a unique firing pattern and slow functional maturation. Based on their distinct morphology we termed them "small axonless neurons" and indeed, unlike other cortical neurons, they communicate with their neuronal partners via dendrodendritic synapses. Finally, we provide evidence that the number of small axonless neurons is enhanced by odor enrichment, a further indication that they integrate into neural circuits and participate to olfactory processing.

Diazepam binding inhibitor governs neurogenesis of excitatory and inhibitory neurons during embryonic development via GABA signaling.

Of the neurotransmitters that influence neurogenesis, gamma-aminobutyric acid (GABA) plays an outstanding role, and GABA receptors support non-synaptic signaling in progenitors and migrating neurons. Here, we report that expression levels of diazepam binding inhibitor (DBI), an endozepine that modulates GABA signaling, regulate embryonic neurogenesis, affecting the long-term outcome regarding the number of neurons in the postnatal mouse brain. We demonstrate that DBI is highly expressed in radial glia and intermediate progenitor cells in the germinal zones of the embryonic mouse brain that give rise to excitatory and inhibitory cells. The mechanism by which DBI controls neurogenesis involves its action as a negative allosteric modulator of GABA-induced currents on progenitor cells that express GABAA receptors containing γ2 subunits. DBI's modulatory effect parallels that of GABAA-receptor-mediating signaling in these cells in the proliferative areas, reflecting the tight control that DBI exerts on embryonic neurogenesis.

Neurogenesis and widespread forebrain migration of distinct GABAergic neurons from the postnatal subventricular zone.

Most forebrain GABAergic interneurons in rodents are born during embryonic development in the ganglionic eminences (GE) and migrate tangentially into the cortical plate. A subset, however, continues to be generated postnatally in the subventricular zone (SVZ). These interneurons populate the olfactory bulb (OB) reached via migration in the rostral migratory stream (RMS). Employing transgenic mice expressing EGFP in 5-HT(3)-positive neurons, we identified additional migratory pathways in the early postnatal brain. Time-lapse imaging experiments revealed massive migration of EGFP-positive cells from the SVZ into numerous forebrain regions, including cortex, striatum, and nucleus accumbens. The neuronal fate of the migratory EGFP-labeled cells was indicated by their doublecortin (DCX) expression. Birthdating experiments, by using 5-bromo-2'-deoxyuridine (BrdU) and retrovirus-based experiments, provided evidence that migrating neuroblasts were born in the SVZ postnatally and developed a distinct GABAergic phenotype. Our results demonstrate that the SVZ is a reservoir of GABAergic interneurons not only for the OB, but also for other cortical and subcortical areas.

From benzodiazepines to fatty acids and beyond: revisiting the role of ACBP/DBI.

Four decades ago Costa and colleagues identified a small, secreted polypeptide in the brain that can displace the benzodiazepine diazepam from the GABAA receptor, and was thus termed diazepam binding inhibitor (DBI). Shortly after, an identical polypeptide was identified in liver by its ability to induce termination of fatty acid synthesis, and was named acyl-CoA binding protein (ACBP). Since then, ACBP/DBI has been studied in parallel without a clear and integrated understanding of its dual roles. The first genetic loss-of-function models have revived the field, allowing targeted approaches to better understand the physiological roles of ACBP/DBI in vivo. We discuss the roles of ACBP/DBI in central and tissue-specific functions in mammals, with an emphasis on metabolism and mechanisms of action.

Neurogenesis in the adult brain functionally contributes to the maintenance of chronic neuropathic pain.

Maladaptive adult neurogenesis in the mammalian brain has been associated with diverse behaviors including disrupted learning, negative mood disorders and psychiatric conditions. However, its functional role in the generation and maintenance of chronic pathological pain has not yet been elucidated. Using an inducible genetic deletion in vivo mouse model, different behavioural paradigms and home cage monitoring systems, we show that an absence of adult neurogenesis does not impact the development of neuropathic injury-induced peripheral nociceptive hypersensitivity, but rather promotes the recovery of pathological pain as well as improves parameters associated with the state of well-being of the injured mice. These results provide a mechanistic insight into the mechanisms of chronic pain and implicate neurogenic processes as a potential therapeutic target for reducing pain and improving the quality of life for patients.

[Consensus about Health constance for children and adolescents in order to develop phisical activities and sports. Update 2021]. / Consenso sobre la constancia de salud del niño y del adolescente para la realización de actividades físicas y/o deportivas. Actualización 2021.

This document is the update of the Consensus published by SAP in 2014, so that no child nor adolescent is excluded from their right to health and physical activity. The periodic medical control and the school physical education are fundamental tools. As a result, of the SARS-CoV-2 pandemic, sports practice decreased dramatically. Recommendations are formulated that serve as a reference to pediatricians, members of health care teams, educational institutions, and sports at the local, regional, and national level in the preparation of the health certificate for a child or adolescent who will participate in physical or sports activities. The pediatrician will evaluate the child or adolescent knowing that to carry out a healthy life, must perform physical activities with moderate or vigorous intensity. The health certificate implies a shared responsibility between the child or adolescent and/or the responsible adult, the doctor, the physical education teachers and/or the coaches in charge.

Este documento es la actualización del consenso publicado por la Sociedad Argentina de Pediatría en 2014, para que ningún niño, niña y adolescente (NNA) del país quede excluido de su derecho a la salud y a la actividad física. El control médico periódico y la educación física en el ámbito escolar son herramientas fundamentales para ejercer estos derechos. A raíz de la pandemia del coronavirus de tipo 2 causante del síndrome respiratorio agudo grave (SARS-CoV-2, por su sigla en inglés) disminuyó de manera notable la práctica deportiva. Se formulan recomendaciones que sirvan de referencia a pediatras, integrantes de los equipos de salud, instituciones educativas y deportivas en los niveles local, regional y nacional para la elaboración de la constancia de salud de los NNA que participarán en actividades físicas y deportivas. El pediatra evaluará al NNA sabiendo que para llevar una vida saludable éste debe realizar actividades físicas de moderada a vigorosa intensidad. La Constancia de Salud implica una responsabilidad compartida entre el NNA y/o adulto responsable, el médico, los profesores de educación física y/o los entrenadores a cargo.

Cysteine residues in the large extracellular loop (EC2) are essential for the function of the stress-regulated glycoprotein M6a.

Gpm6a was identified as a stress-responsive gene in the hippocampal formation. This gene is down-regulated in the hippocampus of both socially and physically stressed animals, and this effect can be reversed by antidepressant treatment. Previously we showed that the stress-regulated protein M6a is a key modulator for neurite outgrowth and filopodium/spine formation. In the present work, mutational analysis was used to characterize the action of M6a at the molecular level. We show that four cysteines 162, 174, 192, and 202 within EC2 are functionally crucial sites. The presence of cysteines 162 and 202 is essential for the efficient cell surface expression of the M6a protein. In contrast, cysteines 174 and 192, which form a disulfide bridge as shown by biochemical analysis, are not required for the efficient surface expression of M6a. Their mutation to alanine does not interfere with the localization of M6a to filopodial protrusions in primary hippocampal neurons. The neurons expressing C174A and/or C192A mutants display decreased filopodia number. In non-permeabilized cells, these mutant proteins are not recognized by a function-blocking monoclonal antibody directed to M6a. Moreover, neurons in contact with axons expressing C174A/C192A mutant display significantly lower density of presynaptic clusters over their dendrites. Taken together, this study demonstrates that cysteines in the EC2 domain are critical for the role of M6a in filopodium outgrowth and synaptogenesis.

Conserved cellular function and stress-mediated regulation among members of the proteolipid protein family.

Chronic stress causes morphological alterations in the hippocampus of rodents and tree shrews, including atrophy of CA3 dendrites and loss of synapses. The molecular mechanisms underlying these structural changes remain largely unknown. We have previously identified M6a as a stress responsive gene and shown that M6a is involved in filopodium/spine outgrowth and, likely, synapse formation. M6a belongs to the proteolipid protein (PLP) family, all of their members having four transmembrane domains that allow their localization at the plasma membrane. In the present work, we analyzed other members of this family, the closely related M6b as well as PLP and its splice variant DM20. We found that chronic restraint stress in mice reduces M6b and DM20, but not PLP, mRNA levels in the hippocampus. In addition, M6b and DM20, but again not PLP, induce filopodium formation in primary cultures of hippocampal neurons. Several M6b protein isoforms were studied, all of them having similar effects except for the one lacking the transmembrane domains. Our results reveal a conserved cellular function and a stress-mediated regulation among members of the proteolipid protein family, suggesting an involvement of proteolipid proteins in the stress response.

Reciprocal Interaction between Vascular Filopodia and Neural Stem Cells Shapes Neurogenesis in the Ventral Telencephalon.

Angiogenesis and neurogenesis are tightly coupled during embryonic brain development. However, little is known about how these two processes interact. We show that nascent blood vessels actively contact dividing neural stem cells by endothelial filopodia in the ventricular zone (VZ) of the murine ventral telencephalon; this association is conserved in the human ventral VZ. Using mouse mutants with altered vascular filopodia density, we show that this interaction leads to prolonged cell cycle of apical neural progenitors (ANPs) and favors early neuronal differentiation. Interestingly, pharmacological experiments reveal that ANPs induce vascular filopodia formation by upregulating vascular endothelial growth factor (VEGF)-A in a cell-cycle-dependent manner. This mutual relationship between vascular filopodia and ANPs works as a self-regulatory system that senses ANP proliferation rates and rapidly adjusts neuronal production levels. Our findings indicate a function of vascular filopodia in fine-tuning neural stem cell behavior, which is the basis for proper brain development.