Dispersal history of SARS-CoV-2 in Galicia, Spain.

The dynamics of SARS-CoV-2 transmission are influenced by a variety of factors, including social restrictions and the emergence of distinct variants. In this study, we delve into the origins and dissemination of the Alpha, Delta, and Omicron variants of concern in Galicia, northwest Spain. For this, we leveraged genomic data collected by the EPICOVIGAL Consortium and from the GISAID database, along with mobility information from other Spanish regions and foreign countries. Our analysis indicates that initial introductions during the Alpha phase were predominantly from other Spanish regions and France. However, as the pandemic progressed, introductions from Portugal and the USA became increasingly significant. Notably, Galicia's major coastal cities emerged as critical hubs for viral transmission, highlighting their role in sustaining and spreading the virus. This research emphasizes the critical role of regional connectivity in the spread of SARS-CoV-2 and offers essential insights for enhancing public health strategies and surveillance measures.

Astrocytes Undergo Metabolic Reprogramming in the Multiple Sclerosis Animal Model.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that presents a largely unknown etiopathology. The presence of reactive astrocytes in MS lesions has been described for a long time; however, the role that these cells play in the pathophysiology of MS is still not fully understood. Recently, we used an MS animal model to perform high-throughput sequencing of astrocytes' transcriptome during disease progression. Our data show that astrocytes isolated from the cerebellum (a brain region typically affected in MS) showed a strong alteration in the genes that encode for proteins related to several metabolic pathways. Specifically, we found a significant increase in glycogen degradation, glycolytic, and TCA cycle enzymes. Together with these alterations, we detected an upregulation of genes that characterize "astrocyte reactivity". Additionally, at each disease time point we also reconstructed the morphology of cerebellum astrocytes in non-induced controls and in EAE animals, near lesion regions and in the normal-appearing white mater (NAWM). We found that near lesions, astrocytes presented increased length and complexity compared to control astrocytes, while no significant alterations were observed in the NAWM. How these metabolic alterations are linked with disease progression is yet to be uncovered. Herein, we bring to the literature the hypothesis of performing metabolic reprogramming as a novel therapeutic approach in MS.

Learning the Biochemical Basis of Axonal Guidance: Using Caenorhabditis elegans as a Model.

AIM: Experimental models are a powerful aid in visualizing molecular phenomena. This work reports how the worm Caenorhabditis elegans (C. elegans) can be effectively explored for students to learn how molecular cues dramatically condition axonal guidance and define nervous system structure and behavior at the organism level. Summary of work: A loosely oriented observational activity preceded detailed discussions on molecules implied in axonal migration. C. elegans mutants were used to introduce second-year medical students to the deleterious effects of gene malfunctioning in neuron response to extracellular biochemical cues and to establish links between molecular function, nervous system structure, and animal behavior. Students observed C. elegans cultures and associated animal behavior alterations with the lack of function of specific axon guidance molecules (the soluble cue netrin/UNC-6 or two receptors, DCC/UNC-40 and UNC-5H). Microscopical observations of these strains, in combination with pan-neuronal GFP expression, allowed optimal visualization of severely affected neurons. Once the list of mutated genes in each strain was displayed, students could also relate abnormal patterns in axon migration/ventral and dorsal nerve cord neuron formation in C. elegans with mutated molecular components homologous to those in humans. SUMMARY OF RESULTS: Students rated the importance and effectiveness of the activity very highly. Ninety-three percent found it helpful to grasp human axonal migration, and all students were surprised with the power of the model in helping to visualize the phenomenon.

Age-related changes in mice behavior and the contribution of lipocalin-2.

Aging causes considerable changes in the nervous system, inducing progressive and long-lasting loss of physiological integrity and synaptic plasticity, leading to impaired brain functioning. These age-related changes quite often culminate in behavioral dysfunctions, such as impaired cognition, which can ultimately result in various forms of neurodegenerative disorders. Still, little is known regarding the effects of aging on behavior. Moreover, the identification of factors involved in regenerative plasticity, in both the young and aged brain, is scarce but crucial from a regenerative point of view and for our understanding on the mechanisms that control the process of normal aging. Recently, we have identified the iron-trafficking protein lipocalin-2 (LCN2) as novel regulator of animal behavior and neuronal plasticity in the young adult brain. On the other hand, others have proposed LCN2 as a biological marker for disease progression in neurodegenerative disorders such as Alzheimer's disease and multiple sclerosis. Still, and even though LCN2 is well accepted as a regulator of neural processes in the healthy and diseased brain, its contribution in the process of normal aging is not known. Here, we performed a broad analysis on the effects of aging in mice behavior, from young adulthood to middle and late ages (2-, 12-, and 18-months of age), and in the absence of LCN2. Significant behavioral differences between aging groups were observed in all the dimensions analyzed and, in mice deficient in LCN2, aging mainly reduced anxiety, while sustained depressive-like behavior observed at younger ages. These behavioral changes imposed by age were further accompanied by a significant decrease in cell survival and neuronal differentiation at the hippocampus. Our results provide insights into the role of LCN2 in the neurobiological processes underlying brain function and behavior attributed to age-related changes.

Correlation Analysis between Hemoglobin and C-Reactive Protein in Patients Admitted to an Emergency Unit.

Anemia and inflammation are common clinical conditions in emergency departments. This study explored a cohort of patients admitted to the emergency department with a particular interest in determining the frequency of anemia and inflammation and the association between hemoglobin (Hb) and C-reactive protein (CRP) concentrations. The study included 125 patients categorized according to their demographic (gender and age) and clinical condition (Hb and CRP concentrations, pathological background, and diagnostic). We found that anemia and inflammation were simultaneously present in 36.0% of the cohort, reaching 67.0% in patients that were subsequently hospitalized. The Hb level was significantly lower in patients with elevated concentration of CRP when compared to individuals with normal CRP levels (11.58 ± 2.23 vs. 13.25 ± 1.80, p = 0.001); furthermore, we found a significantly negative correlation between Hb concentration and the CRP level (rs = -0.42, p < 0.001). The linear regression model applied to the cohort showed that CRP levels explain 15% of Hb variations. The sensitivity of the CRP/Hb ratio (cut-off = 1.32) as a predictor of hospitalization was 80.0%, with a specificity of 68.4% for all patients. These findings confirmed the prevalence of anemia and inflammation and identified a moderate but significant association between Hb and serum CRP in a heterogeneous group of patients admitted to the emergency department.

Novel concept of exosome-like liposomes for the treatment of Alzheimer's disease.

Exosomes are cell-derived vesicles that act as carriers for proteins and nucleic acids, with therapeutic potential and high biocompatibility. We propose a new concept of exosome-like liposomes for controlled delivery. The goal of this work was to develop a new type of liposomes with a unique mixture of phospholipids, similar to naturally occurring exosomes but overcoming their limitations of heterogeneity and low productivity, for therapeutic delivery of bioactive compounds. Curcumin was chosen as model compound, as it is a phytochemical molecule known to have antioxidant and anti-inflammatory properties, which can protect the brain against oxidative stress and reduce ß-amyloid accumulation, major hallmarks of Alzheimer's disease (AD). These new liposomes can efficiently encapsulate hydrophobic curcumin, yielding particles with a size smaller than 200 nm, and a polydispersity index lower than 0.20, which make them ideal for crossing the blood-brain barrier. These particles have a long shelf life, being stable up to 6 months. The curcumin encapsulation efficiency was higher than 85% (up to approximately 94%). Curcumin-loaded liposomes were not cytotoxic (up to 20 µM curcumin, and 200 µM of exo-liposomes), and significantly reduced oxidative stress induced in SH-SY5Y neuronal cells, indicating their potential for neuroprotection. They also do not show any toxicity and are internalized in zebrafish embryos, concentrating in lipid enriched areas, as the brain and the yolk sac. Such innovative carriers are a new effective approach to deliver drugs into the brain, as these are stable, protect the cargo and are uptaken by neuronal cells. Upon internalization, liposomes release the therapeutic biomolecules, resulting in successful neuroprotection, being a positive alternative strategy for AD therapy.

Altered astrocytic function in experimental neuroinflammation and multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) that affects about 2.5 million people worldwide. In MS, the patients' immune system starts to attack the myelin sheath, leading to demyelination, neurodegeneration, and, ultimately, loss of vital neurological functions such as walking. There is currently no cure for MS and the available treatments only slow the initial phases of the disease. The later-disease mechanisms are poorly understood and do not directly correlate with the activity of immune system cells, the main target of the available treatments. Instead, evidence suggests that disease progression and disability are better correlated with the maintenance of a persistent low-grade inflammation inside the CNS, driven by local glial cells, like astrocytes and microglia. Depending on the context, astrocytes can (a) exacerbate inflammation or (b) promote immunosuppression and tissue repair. In this review, we will address the present knowledge that exists regarding the role of astrocytes in MS and experimental animal models of the disease.

Structural and molecular correlates of cognitive aging in the rat.

Aging is associated with cognitive decline. Herein, we studied a large cohort of old age and young adult male rats and confirmed that, as a group, old  rats display poorer spatial learning and behavioral flexibility than younger adults. Surprisingly, when animals were clustered as good and bad performers, our data revealed that while in younger animals better cognitive performance was associated with longer dendritic trees and increased levels of synaptic markers in the hippocampus and prefrontal cortex, the opposite was found in the older group, in which better performance was associated with shorter dendrites and lower levels of synaptic markers. Additionally, in old, but not young individuals, worse performance correlated with increased levels of BDNF and the autophagy substrate p62, but decreased levels of the autophagy complex protein LC3. In summary, while for younger individuals "bigger is better", "smaller is better" is a more appropriate aphorism for older subjects.

Voluntary running rescues the defective hippocampal neurogenesis and behaviour observed in lipocalin 2-null mice.

The continuous generation of new neurons in the adult mammalian hippocampus is a form of neural plasticity that modulates learning and memory functions, and also emotion (anxiety and depression). Among the factors known to modulate adult hippocampal neurogenesis and brain function, lipocalin-2 (LCN2) was recently described as a key regulator of neural stem cells (NSCs) proliferation and commitment, with impact on several dimensions of behaviour. Herein, we evaluated whether voluntary running, a well-known regulator of cell genesis, rescue the deficient adult hippocampal neurogenesis observed in mice lacking LCN2. We observed that running, by counteracting oxidative stress in NSCs, reverses LCN2-null mice defective hippocampal neurogenesis, as it promotes NSCs cell cycle progression and maturation, resulting in a partial reduction in anxiety and improved contextual behaviour. Together, these findings demonstrate that running is a positive modulator of adult hippocampal neurogenesis and behaviour in mice lacking LCN2, by impacting on the antioxidant kinetics of NSCs.

Adult Hippocampal Neurogenesis Modulation by the Membrane-Associated Progesterone Receptor Family Member Neudesin.

Neudesin (Neuron-derived neurotrophic factor, NENF), a membrane-associated progesterone receptor family (MAPR) member, is a neuron secreted protein with neurotrophic properties during embryonic stages. However, its role in the adult brain is still poorly addressed. In this study we have used neudesin-null (Nenf-/-) mice and performed a characterization of the proliferation state of the adult neurogenic niches, the adult subventricular zone (SVZ) and the hippocampus subgranular zone (SGZ). Nenf-/- males did not presented any deficits in proliferation in the SVZ neither in vivo nor in vitro. On the other hand a decrease in cell proliferation in the SGZ was observed, as well as a decrease in the number of newborn neurons in the dentate gyrus (DG) that was accompanied by impaired context discrimination in a contextual fear conditioning (CFC) task. Since NENF neurotrophic action is suggested to occur via the formation of a progesterone stability complex for the activation of non-genomic cascade, we further evaluated progesterone metabolism in the absence of NENF. Interestingly, expression of progesterone catabolic rate-determining enzyme, 5-α-reductase was upregulated in the DG of Nenf-/-, together with a significant increase in the expression of the δGABAA receptor gene, involved in DG tonic inhibition. Taken together, these findings add in vivo evidence on the neurotrophic properties of NENF in the adult brain. Furthermore, the mechanism of action of NENF in this process might implicate neurosteroids modulation, at least in the DG.

Metabolism and adult neurogenesis: Towards an understanding of the role of lipocalin-2 and iron-related oxidative stress.

The process of generating new functional neurons in the adult mammalian brain occurs from the local neural stem and progenitor cells and requires tight control of the progenitor cell's activity. Several signaling pathways and intrinsic/extrinsic factors have been well studied over the last years, but recent attention has been given to the critical role of cellular metabolism in determining the functional properties of progenitor cells. Here, we review recent advances in the current understanding of when and how metabolism affects neural stem cell (NSC) behavior and subsequent neuronal differentiation and highlight the role of lipocalin-2 (LCN2), a protein involved in the control of oxidative stress, as a recently emerged regulator of NSC activity and neuronal differentiation.

The choroid plexus in health and in disease: dialogues into and out of the brain.

This article brings the choroid plexus into the context of health and disease. It is remarkable that the choroid plexus, composed by a monolayer of epithelial cells that lie in a highly vascularized stroma, floating within the brain ventricles, gets so little attention in major physiology and medicine text books and in the scientific literature in general. Consider that it is responsible for producing most of the about 150mL of cerebrospinal fluid that fills the brain ventricles and the subarachnoid space and surrounds the spinal cord in the adult human central nervous system, which is renewed approximately 2-3 times daily. As such, its activity influences brain metabolism and function, which will be addressed. Reflect that it contains an impressive number of receptors and transporters, both in the apical and basolateral sides of the epithelial cells, and as such is a key structure for the communication between the brain and the periphery. This will be highlighted in the context of neonatal jaundice, multiple sclerosis and Alzheimer's disease. Realize that the capillaries that irrigate the choroid plexus stroma do not possess tight junctions and that the blood flow to the choroid plexus is five times higher than that in the brain parenchyma, allowing for a rapid sensing system and delivery of molecules such as nutrients and metals as will be revised. Recognize that certain drugs reach the brain parenchyma solely through the choroid plexus epithelia, which has potential to be manipulated in diseases such as neonatal jaundice and Alzheimer's disease as will be discussed. Without further notice, it must be now clear that understanding the choroid plexus is necessary for comprehending the brain and how the brain is modulated and modulates all other systems, in health and in disease. This review article intends to address current knowledge on the choroid plexus, and to motivate the scientific community to consider it when studying normal brain physiology and diseases of the central nervous system. It will guide the reader through several aspects of the choroid plexus in normal physiology, in diseases characteristic of various periods of life (newborns-kernicterus, young adults-multiple sclerosis and the elder-Alzheimer's disease), and how sex-differences may relate to disease susceptibility.

Insights on the pathophysiology of Alzheimer's disease: The crosstalk between amyloid pathology, neuroinflammation and the peripheral immune system.

Alzheimer's disease (AD) is the most common form of dementia, whose prevalence is growing along with the increased life expectancy. Although the accumulation and deposition of amyloid beta (Aß) peptides in the brain is viewed as one of the pathological hallmarks of AD and underlies, at least in part, brain cell dysfunction and behavior alterations, the etiology of this neurodegenerative disease is still poorly understood. Noticeably, increased amyloid load is accompanied by marked inflammatory alterations, both at the level of the brain parenchyma and at the barriers of the brain. However, it is debatable whether the neuroinflammation observed in aging and in AD, together with alterations in the peripheral immune system, are responsible for increased amyloidogenesis, decreased clearance of Aß out of the brain and/or the marked deficits in memory and cognition manifested by AD patients. Herein, we scrutinize some important traits of the pathophysiology of aging and AD, focusing on the interplay between the amyloidogenic pathway, neuroinflammation and the peripheral immune system.

Nano- and micro-based systems for immunotolerance induction in multiple sclerosis.

It is estimated that more than 2.5 million individuals worldwide have multiple sclerosis (MS). MS is an autoimmune neurodegenerative disease resulting from the destruction of the myelin sheath that enwraps axons driven by an immune cell attack to the central nervous system. Current therapeutic programs for MS focus in immunosuppression and more recently in the use of immunomodulatory molecules. These therapeutic approaches provide significant improvements in the management of the disease, but are frequently associated with an increased susceptibility of opportunistic infection. In this commentary, we highlight the application of nano and micro-technologies as emerging and innovative solutions for MS therapy with the potential to restore immune homeostasis via antigen-specific interactions. Furthermore, we propose and discuss the usage of a minimally invasive approach, namely microneedle patches, as a new therapeutic route. Microneedle patches for the delivery of specific antigens to restore immunotolerance in the context of multiple sclerosis.

Synthesis and antimicrobial activity of novel 5-aminoimidazole-4-carboxamidrazones.

A mild and simple method was developed to prepare a series of fifteen 5-aminoimidazole 4-carboxamidrazones, starting from the easily accessible 5-amino-4-cyanoformimidoyl imidazoles. The antimicrobial activity of these novel amidrazones was screened against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli, Pseudomonas aeruginosa) bacteria and Candida sp. (Candida albicans, Candida krusei, Candida parapsilosis). Only a subset of compounds displayed fair-moderate activity against S. aureus and E. coli but all exhibited activity against Candida sp. The three most potent antifungal compounds were further tested against Cryptococcus neoformans, Aspergillus fumigatus and three dermatophytes (Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum gypseum). These three hit compounds strongly inhibited C. krusei and C. neoformans growth, although their activity on filamentous fungi was very weak when compared to the activity on yeasts.

Blood-brain-barriers in aging and in Alzheimer's disease.

The aging process correlates with a progressive failure in the normal cellular and organ functioning; these alterations are aggravated in Alzheimer's disease (AD). In both aging and AD there is a general decrease in the capacity of the body to eliminate toxic compounds and, simultaneously, to supply the brain with relevant growth and nutritional factors. The barriers of the brain are targets of this age related dysfunction; both the endothelial cells of the blood-brain barrier and the choroid plexus epithelial cells of the blood-cerebrospinal fluid barrier decrease their secretory capacity towards the brain and their ability to remove toxic compounds from the brain. Additionally, during normal aging and in AD, the permeability of the brain barriers increase. As such, a greater contact of the brain parenchyma with the blood content alters the highly controlled neural environment, which impacts on neural function. Of interest, the brain barriers are more than mere obstacles to the passage of molecules and cells, and therefore active players in brain homeostasis, which is still to be further recognized and investigated in the context of health and disease. Herein, we provide a review on how the brain barriers change during aging and in AD and how these processes impact on brain function.

Unbiased stereological method to assess proliferation throughout the subependymal zone.

The subependymal zone (SEZ), frequently named as adult subventricular zone (SVZ), is a niche of adult neural stem and progenitor cells that lines a large extension of the lateral ventricles of the brain. The majority of the studies do not analyze the SEZ throughout its entire extension. Instead, studies of cell populations within the SEZ typically focus their analysis on a narrow space between specific bregma coordinates that provides a perspective of only a small portion of the SEZ. We have previously proposed a standard division for the SEZ at the anterior-posterior and dorsal-ventral axes based on external brain anatomical hallmarks (Falcao et al., PLoS One 7:e38647, 2012). Herein, we describe in detail the procedure and a stereological approach that can be used to obtain an unbiased estimation of the SEZ cell proliferation under physiological and pathological conditions. This approach takes into consideration clear SEZ anatomical divisions, both on the anterior-posterior and dorsal-ventral axes, which will standardize future studies on the SEZ.

The path from the choroid plexus to the subventricular zone: go with the flow!

IN ADULT MAMMALS, UNDER PHYSIOLOGICAL CONDITIONS, NEUROGENESIS, THE PROCESS OF GENERATING NEW FUNCTIONAL NEURONS FROM PRECURSOR CELLS, OCCURS MAINLY IN TWO BRAIN AREAS: the subgranular zone in the dentate gyrus of the hippocampus, and the subventricular zone (SVZ) lining the walls of the brain lateral ventricles. Taking into account the location of the SVZ and the cytoarchitecture of this periventricular neural progenitor cell niche, namely the fact that the slow dividing primary progenitor cells (type B cells) of the SVZ extend an apical primary cilium toward the brain ventricular space which is filled with cerebrospinal fluid (CSF), it becomes likely that the composition of the CSF can modulate both self-renewal, proliferation and differentiation of SVZ neural stem cells. The major site of CSF synthesis is the choroid plexus (CP); quite surprisingly, however, it is still largely unknown the contribution of molecules specifically secreted by the adult CP as modulators of the SVZ adult neurogenesis. This is even more relevant in light of recent evidence showing the ability of the CP to adapt its transcriptome and secretome to various physiologic and pathologic stimuli. By giving particular emphasizes to growth factors and axonal guidance molecules we will illustrate how CP-born molecules might play an important role in the SVZ niche cell population dynamics.

Topographical analysis of the subependymal zone neurogenic niche.

The emerging model for the adult subependymal zone (SEZ) cell population indicates that neuronal diversity is not generated from a uniform pool of stem cells but rather from diverse and spatially confined stem cell populations. Hence, when analysing SEZ proliferation, the topography along the anterior-posterior and dorsal-ventral axes must be taken into account. However, to date, no studies have assessed SEZ proliferation according to topographical specificities and, additionally, SEZ studies in animal models of neurological/psychiatric disorders often fail to clearly specify the SEZ coordinates. This may render difficult the comparison between studies and yield contradictory results. More so, by focusing in a single spatial dimension of the SEZ, relevant findings might pass unnoticed. In this study we characterized the neural stem cell/progenitor population and its proliferation rates throughout the rat SEZ anterior-posterior and dorsal-ventral axes. We found that SEZ proliferation decreases along the anterior-posterior axis and that proliferative rates vary considerably according to the position in the dorsal-ventral axis. These were associated with relevant gradients in the neuroblasts and in the neural stem cell populations throughout the dorsal-ventral axis. In addition, we observed spatially dependent differences in BrdU/Ki67 ratios that suggest a high variability in the proliferation rate and cell cycle length throughout the SEZ; in accordance, estimation of the cell cycle length of the neuroblasts revealed shorter cell cycles at the dorsolateral SEZ. These findings highlight the need to establish standardized procedures of SEZ analysis. Herein we propose an anatomical division of the SEZ that should be considered in future studies addressing proliferation in this neural stem cell niche.