BACKGROUND:It has been suggested that peripheral inflammation and immune-mediated neuronal dysfunction play a decisive role in the pathophysiology of obsessive-compulsive disorder (OCD). However, work addressing this hypothesis is mostly based on small samples and heterogeneous methodologies, and has led to inconsistent results. Here we conducted the largest study to date comparing an extensive panel of immune markers in the peripheral blood between adult patients with OCD and healthy controls. METHODS:One-hundred and thirty-nine patients with OCD and 131 age and sex-matched controls were assessed cross-sectionally for sociodemographic and clinical characteristics, and collection of peripheral blood. The concentration of high-sensitivity C-reactive protein (main outcome), of twelve cytokines, and the prevalence of positivity for anti-nuclear, anti-thyroid peroxidase, anti-thyroglobulin, and anti-basal ganglia antibodies (secondary outcomes), were assessed in the serum or plasma using ELISA. In a subsample of 176 participants, we further compared cytokine gene expression using RT-qPCR, between groups. RESULTS:While patients had a significantly higher prevalence of self-reported general medical disorders, we consistently found similar levels of immune markers when comparing patients and controls, with only minor, non-significant, differences. In stratified analyses according to age of onset, current depressive episode, recruitment centre and medication status, the lack of group differences was consistent, except for higher IL-8 gene expression in patients with co-morbid depression, while subgroup analyses within the patient group revealed lower TGF-β concentration in patients with early-onset OCD. DISCUSSION:Our findings support that, contrary to what has been shown in mood and psychotic disorders, in symptomatic and medicated adults with OCD there are only minor differences relative to healthy volunteers in cross-sectional assessments of peripheral immune markers, that may reflect co-morbid depression and/or early-onset of the disorder.

Healthy brain development and function highly depend on the choroid plexus. Temporal alterations in the cellular landscape and gene expression of choroid plexus cells can alter immune cell trafficking in the brain and cerebrospinal fluid composition, ultimately impacting brain dynamics. Here, we performed a comprehensive multi-omics analysis—including bulk and single-cell transcriptomics and epigenomics—of the lateral ventricle choroid plexus across early postnatal and adult stages in mice and rats. We uncovered striking changes in the choroid plexus cellular composition from neonatal to adult stages, accompanied by transcriptional remodeling of all main cell types. Immune cells were markedly increased in adulthood and immune cell profiling revealed an altered cell-type diversity through time. Surprisingly, we observed an early gene activation of host-defense genes in all choroid plexus main cell types, beginning in the neonatal period and progressively increasing into young adulthood. Moreover, some genes induced in epithelial cells in response to inflammation were found to be epigenetically primed, despite not being transcriptionally active. Epithelial cells exhibited subtype diversity and plasticity, with distinct gene expression programs and chromatin accessibility profiles emerging over time. Notably, we identified a novel epithelial cell subtype with unique gene markers suggesting a specialized function potentially linked to neuro-signaling. Ligand-receptor interaction analysis revealed a progressive remodeling of cellular crosstalk networks during choroid plexus maturation, suggesting dynamic intercellular signaling as the tissue develops. Our study offers a comprehensive atlas of transcriptional activity and chromatin accessibility in choroid plexus cells, providing a valuable resource to guide future efforts in targeting gene expression at the choroid plexus for therapeutical purposes. ### Competing Interest Statement The authors have declared no competing interest. Swedish Research Council, https://ror.org/03zttf063, 2019-02030, 2022-06725 la Caixa Foundation (ID100010434), LCF/BQ/PI19/11690005 Fundação para a Ciência e Tecnologia, 2020.02753.CEECIND, 2024.08336.CPCA.A0, LA/P/0050/2020, UID/06304/2023 Bial (Portugal), https://ror.org/02htdjb57, Grant (217/12)

It has been suggested that immune-mediated neuronal damage plays a decisive role in the etiology of obsessive-compulsive disorder (OCD). Here we assessed an extensive panel of immune markers in the peripheral blood of two samples of patients with OCD and matched controls, recruited in distinct geographical areas. Participants were assessed cross-sectionally for sociodemographic and clinical characteristics. High-sensitivity C-reactive protein, twelve cytokines, anti-nuclear, anti-thyroid peroxidase, anti-thyroglobulin, and anti-basal ganglia antibodies were assessed using ELISA. Cytokine gene expression was assessed in one of the populations using RT-qPCR. While patients had a significantly higher prevalence of self-reported general medical disorders, we consistently found similar systemic immune indicators between patients (n=139) and controls (n=131), across markers and populations. Our findings support that, contrary to what has been consistently shown in mood and psychotic disorders, in OCD there are no changes in peripheral immune function, when assess cross-sectionally in symptomatic adults.

Alzheimer's disease (AD) is characterized by progressive cognitive decline and neuropathological changes, yet the underlying neurobiological mechanisms remain elusive. Here, we employed a multimodal longitudinal neuroimaging approach, using anatomical and functional sequences on a high field magnetic resonance imaging (MRI) preclinical scanner, to investigate alterations in brain connectivity and white matter microstructure in a transgenic mouse model of AD (J20) when compared to wild-type (WT) littermates. Functional connectivity analysis revealed distinct network disruptions in J20 mice, primarily involving connections between posterior and anterior brain regions; importantly, a significant interaction between group and age highlighted an exacerbation of these connectivity changes with advancing age in J20 mice. In addition, significant reductions in fractional anisotropy (FA) were observed in the corpus callosum of J20 mice compared to WT, indicative of microstructural alterations consistent with white matter pathology. The observed alterations in brain connectivity and microstructure provide valuable insights into the spatiotemporal processes underlying AD-related decline and underscore the utility of multimodal neuroimaging in elucidating the neurobiological substrates of AD pathology in animal models.

Accreditation processes for health care professions are designed to ensure that individuals and programs in these fields meet established standards of quality and effectiveness. The accelerating pace of globalization in the health care professions has increased the need for a shared understanding of the vocabulary of evaluation, assessment, and accreditation. The psychometric principles of valid and reliable assessment are commonly accepted, but the terminology is confusing. We believe that all stakeholders – evaluators, faculty, students but also the community – will benefit from a shared language and common set of definitions. We recognize that not all readers will agree with the definitions we propose, but we hope that this guide will help to ensure clarity, consistency, transparency, and fairness, and that it will promote through the stimulation of a debate greater collaboration across national and international boundaries.

Lipocalin-2 (LCN2) is an acute phase protein able to bind iron when complexed with bacterial siderophores. The recent identification of a mammalian siderophore also suggested a physiological role for LCN2 in the regulation of iron levels and redox state. In the central nervous system, the deletion of LCN2 induces deficits in neural stem cells proliferation and commitment, with an impact on the hippocampal-dependent contextual fear discriminative task. Additionally, stress is a well-known regulator of cell genesis and is known to decrease adult hippocampal cell proliferation and neurogenesis. Although voluntary running, another well-known regulator of neurogenesis, is sufficient to rescue the defective hippocampal neurogenesis and behavior in LCN2-null mice by promoting stem cells’ cell cycle progression and maturation, the relevance of LCN2-regulated hippocampal neurogenesis in response to stress has never been explored. Here, we show a lack of response by LCN2-null mice to the effects of chronic stress exposure at the cellular and behavioral levels. Together, these findings implicate LCN2 as a relevant mediator of neuronal plasticity and brain function in the adult mammalian brain.

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.

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.

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.

Subjective cognitive decline (SCD) is a state of self-perception of cognitive worsening compared to the normal state, without abnormalities on objective neuropsychological assessments. Since its definition in 2014, this condition has raised considerable interest, once those patients are at higher risk for developing objective cognitive decline, Alzheimer disease and other types of dementia (JESSEN 2020). The inflammatory cytokine network is associated with aging-related diseases, and changes in the release of these substances may impact higher brain functions, such as mood and cognition (NG 2018). Users of basic healthcare units aged 60 years and over without dementia (MMSE≥14) and non-depressed (CES-D<16) from a community sample in São Paulo were assessed with a questionnaire about perceived memory problems (“have you had memory problems lately?”) and for sociodemographic data, cognitive and depression screening. Serum samples were collected for dosages of C-reactive protein (RCP), interferon gamma (IG) and interleukines (IL) 1, 4 and 10. Out of the 529 elderly evaluated in the study, 286 were women, of which 112 (39,1%) had SCD, and 243 men, with 89 (36,6%) having SCD. The SCD group had a mean age of 69.8 years old and a mean of 8.4 years of education, contrasting with 68.3 years of age and 5.07 years of education among those without SCD. The mean age difference was statistically significant. The SCD group had a slightly lower mean dosage of IL-1 and higher mean dosages of IL 4 and 10, IG and RCP, but only the latter reached statistical significance. Our study represents a step further towards understanding the pathophysiology of SCD, as this preclinical condition could be a target of future early interventions for Alzheimer’s disease and other dementia syndromes. References: Jessen F, Amariglio RE et al. The characterisation of subjective cognitive decline. Lancet Neurol. 2020 Mar;19(3):271-278. https://doi.org/10.1016/S1474-4422(19)30368-0 . Ng A et al. IL-1β, IL-6, TNF- α and CRP in Elderly Patients with Depression or Alzheimer’s disease: Systematic Review and Meta-Analysis. Sci Rep. 2018 Aug 13;8(1):12050. https://doi.org/10.1038/s41598-018-30487-6 .

Neuroticism is a multidimensional personality characteristic related to a predisposition to experience psychological distress and negative mood states, and it may be an indicator of worse cognitive and mood outcomes in older adults. It is one type of personality trait described by Costa and McCrae on the Five-Factor Model of Personality. Evidence shows that higher neuroticism scores contribute to chronic stress response that induces neuronal dysfunction, increasing susceptibility to cognitive decline and dementia. However, few studies were conducted previously evaluating associations between neuroticism, depression and cognitive decline. Subjects consist of 76 elderly depressed individuals who were treated over 24 weeks at the Institute of Psychiatry of the Faculty of Medicine in the University of São Paulo. The study subjects were selected from a pool of outpatients and were included in the study if they met the DSM-5 criteria for major depression and were at least 60 years old at baseline enrollment. Those with evident cognitive impairment (Mini Mental State Examination <13) were excluded. At baseline, subjects received standardized clinical assessments administered by a geriatric psychiatrist, including: Mini Mental State Examination; CAMCOG, translated and adapted for Brazilian population; and Montgomery–Asberg Depression Rating Scale (MADRS). The personality assessment was performed using the NEO-FFI inventory. Correlations will be performed using Pearson’s linear coefficient for correlations of numerical variables and Spearman’s for ordinal variables. The sample was predominantly female, with a mean age of 69.1 ± 6.6, low education (70.4% studied up to elementary school), and 45.7% lived with a partner. To understand the relationship between personality factors and cognition parameters, correlations will be conducted and controlled by age and sex. The evaluation of neuroticism is relevant as this personality trait may impact therapeutic interventions, leading to poorer outcomes and worsening cognitive and functional disabilities.

Subjective cognitive decline (SCD) is defined as the self-reported experience of cognitive decline in subjects with normal performance on neuropsychological tests, and expectedly with preserved functionality. This condition is associated with a higher risk for developing objective cognitive decline and dementia. The objective of this study is to carry out a descriptive analysis of the B-ADL scale in elders 24 to 48 months after SCD identification. Forty-three participants aged 60 years and over without clinically relevant depressive symptoms (CESD<16) and without cognitive impairment (MMSE≥14) were randomly selected from a group of users of basic health units in the city of São Paulo. The Clinical Memory Inventory and a questionnaire about perceived memory problems (i.e.: “have you had memory problems lately?”) were applied and 24 to 48 months later an informant answered the Bayer Activities of Daily Living Scale (B-ADL). The mean age of the total sample was 70.7 years. There were 22 women, 45.5% of whom had SCD, and 21 men, 23.8% of whom had SCD. The group with SCD had a mean age of 70.1 years, while in the group without SCD the mean age was 71 years. The group without SCD had a mean B-ADL score of 1.26 and the group with SCD had 1.32 . Eighteen subjects (41.9%) did not score in B-ADL. Out of these, 12 (66,6%) were elderly without SCD while 6 (33,3%) had SCD. After three years of identification, the SCD group showed no functional impairment. Other studies with larger samples may help elucidate the relationship between subjective cognitive decline and functionality.

Microglia have been increasingly implicated in neurodegenerative diseases (NDs), and specific disease associated microglia (DAM) profiles have been defined for several of these NDs. Yet, the microglial profile in Machado–Joseph disease (MJD) remains unexplored. Here, we characterized the profile of microglia in the CMVMJD135 mouse model of MJD. This characterization was performed using primary microglial cultures and microglial cells obtained from disease-relevant brain regions of neonatal and adult CMVMJD135 mice, respectively. Machine learning models were implemented to identify potential clusters of microglia based on their morphological features, and an RNA-sequencing analysis was performed to identify molecular perturbations and potential therapeutic targets. Our findings reveal morphological alterations that point to an increased activation state of microglia in CMVMJD135 mice and a disease-specific transcriptional profile of MJD microglia, encompassing a total of 101 differentially expressed genes, with enrichment in molecular pathways related to oxidative stress, immune response, cell proliferation, cell death, and lipid metabolism. Overall, these results allowed us to define the cellular and molecular profile of MJD-associated microglia and to identify genes and pathways that might represent potential therapeutic targets for this disorder.

BACKGROUND:Orally administered dimethyl fumarate (DMF) presents gastrointestinal adverse effects, such as pain and diarrhea, in addition to flushing and lymphopenia.OBJECTIVE:Solid lipid nanoparticles (SLNs) with DMF were developed for subcutaneous administration.METHODS:DMF-incorporated SLNs and free DMF were tested in mice induced with experimental autoimmune encephalomyelitis (EAE).RESULTS:Preventive treatment of free or incorporated DMF were able to reduce the EAE clinical scores, increase the weight of the animals, reduce the lesion area (demyelination and infiltration), reduce microglial fluorescence intensity and reduce the number of microglial cells and astrocytes, when compared to untreated EAE animals. Groups that received DMF had reduced numbers of T cells, B cells and natural killer (NK) cells in the blood, when compared to the non-induced group.CONCLUSIONS:DMF incorporated in SLNs was as effective as free DMF in reducing the clinical scores of the animals, but with reduced administrations when given subcutaneously. In addition, SLN-DMF preventive treatment partially prevented a reduction in the percentages of T and B cells, in the blood, when compared to preventive treatment with free DMF (oral), which suggests reduction of lymphopenia.

Chronic stress (CS) is associated with a number of neuropsychiatric disorders, and it may also contribute to or exacerbate motor function. However, the mechanisms by which stress triggers motor symptoms are not fully understood. Here, we report that CS functionally alters dorsomedial striatum (DMS) circuits in male mice, by affecting GABAergic interneuron populations and somatostatin positive (SOM) interneurons in particular. Specifically, we show that CS impairs communication between SOM interneurons and medium spiny neurons, promoting striatal overactivation/disinhibition and increased motor output. Using probabilistic machine learning to analyze animal behavior, we demonstrate that in vivo chemogenetic manipulation of SOM interneurons in DMS modulates motor phenotypes in stressed mice. Altogether, we propose a causal link between dysfunction of striatal SOM interneurons and motor symptoms in models of chronic stress.

The contribution of lipocalin-2 (LCN2) to multiple sclerosis (MS) is controversial. Herein, we induced experimental autoimmune encephalomyelitis (EAE) in LCN2-null and wild-type (Wt) mice. While we did not find differences between genotypes regarding clinical score, LCN2-null EAE mice presented decreased expression of interferon gamma and diminished demyelination in the cerebellum. Both genotypes presented similar alterations in the thymocyte and splenocyte populations. In MS patients, higher LCN2 CSF levels at diagnosis could be associated with faster disease progression, however further studies are needed to confirm these results, since this association was lost after controlling for the patients age, presence of oligoclonal bands and gender. Overall, our results support a harmful role for LCN2 in the disease context.

The choroid plexus (CP) is an important structure for the brain. Besides its major role in the production of cerebrospinal fluid (CSF), it conveys signals originating from the brain, and from the circulatory system, shaping brain function in health and in pathology. Previous studies in rodents have revealed altered transcriptome both during aging and in various diseases of the central nervous system, including Alzheimer’s disease. In the present study, a high-throughput sequencing of the CP transcriptome was performed in postmortem samples of clinically healthy individuals aged 50’s through 80’s. The data shows an age-related profile, with the main changes occurring in the transition from the 50’s to the 60’s, stabilizing thereafter. Specifically, neuronal and membrane functions distinguish the transcriptome between the 50’s and the 60’s, while neuronal and axon development and extracellular structure organization differentiate the 50’s from the 70’s. These findings suggest that changes in the CP transcriptome occur early in the aging process. Future studies will unravel whether these relate with processes occurring in late- onset brain diseases.

Medical students tend to have difficulties in developing a holistic view of metabolic pathway and hormone regulation. To address this issue, an interactive activity was implemented for first-year medical students at the School of Medicine, University of Minho, Portugal. Students' previous knowledge on metabolic pathways was evaluated by a pre-test followed by an interactive activity. In the supervised activity, students were challenged to elaborate a diagrammatic representation regarding enzymes, co-factors, and hormonal metabolic regulation in early fasting during the night, as well as in well-fed conditions. The activity was concluded with a post-test to determine the students' learning gains and a few days later students were evaluated by a final exam. Afterwards, students evaluated the activity by filling a questionnaire. Results from four different cohorts showed that the activity resulted in significant learning gains, particularly favoring students who have less prior knowledge. The comparison between the pre-test and the final exam also revealed significant learning gains for low achievers students. On the questionnaires, the majority of the students rated the activity as good or very good. Students agreed that this activity promotes: (a) reactivation of previous knowledge; (b) a better understanding of the interconnections between the metabolic pathways; (c) the application of learned concepts in real scenarios; and (d) sharing knowledge with peers. This study describes an active, unpretentious, and easily implemented activity available for early medical and biochemical curricula.

A worldwide increase in longevity is bringing novel challenges to public health and health care professionals. Cognitive impairment in the elderly may compromise living conditions and precede Alzheimer’s disease (AD), the most prevalent form of dementia. Therefore, finding molecular markers associated with cognitive impairment is of crucial importance. Lipocalin 2 (LCN2), an iron-related protein, has been suggested as a potential marker for mild cognitive impairment (MCI) and AD. This study aimed at investigating the association between LCN2 measured in serum and cerebrospinal fluid (CSF) with cognitive impairment. A cross-sectional design based on two aging cohorts was used: individuals diagnosed with subjective cognitive complaints (SCC), MCI, and AD from a Swedish memory clinic-based cohort, and individuals diagnosed with SCC and AD from a Portuguese cohort. Binary logistic [for the outcome cognitive impairment (MCI + AD) in the Swedish cohort and AD in the Portuguese cohort] and multinomial logistic (for the outcomes MCI and AD) regression analyses were used. No associations were found in both cohorts when controlling for sex, education, and age. This explanatory study suggests that the association between serum and CSF LCN2 concentrations with cognitive impairment reported in the literature must be further analyzed for confounders.