Autosomal Dominant Alzheimer's Disease Mutations in Human Microglia Are Not Sufficient to Trigger Amyloid Pathology in WT Mice but Might Affect Pathology in 5XFAD Mice.

Several genetic variants that affect microglia function have been identified as risk factors for Alzheimer's Disease (AD), supporting the importance of this cell type in disease progression. However, the effect of autosomal dominant mutations in the amyloid precursor protein (APP) or the presenilin (PSEN1/2) genes has not been addressed in microglia in vivo. We xenotransplanted human microglia derived from non-carriers and carriers of autosomal dominant AD (ADAD)-causing mutations in the brain of hCSF1 WT or 5XFAD mice. We observed that ADAD mutations in microglia are not sufficient to trigger amyloid pathology in WT mice. In 5XFAD mice, we observed a non-statistically significant increase in amyloid plaque volume and number of dystrophic neurites, coupled with a reduction in plaque-associated microglia in the brain of mice xenotransplanted with ADAD human microglia compared to mice xenotransplanted with non-ADAD microglia. In addition, we observed a non-statistically significant impairment in working and contextual memory in 5XFAD mice xenotransplanted with ADAD microglia compared to those xenotransplanted with non-ADAD-carrier microglia. We conclude that, although not sufficient to initiate amyloid pathology in the healthy brain, mutations in APP and PSEN1 in human microglia might cause mild changes in pathological and cognitive outcomes in 5XFAD mice in a manner consistent with increased AD risk.

Development and Psychometric Validation of the Breast Cancer Stigma Assessment Scale for Women with Breast Cancer and Its Survivors.

BACKGROUND: The increase in breast cancer cases and breast cancer survival makes it advisable to quantify the impact of the health-related stigma of this disease. PURPOSE/OBJECTIVES: To develop and validate a breast cancer stigma scale in Spanish. METHODS: Women diagnosed with, or survivors of, breast cancer were included. The development of the Breast Cancer Stigma Assessment Scale (BCSAS) involved both a literature review and personal interviews. Content validity was assessed using a Delphi study and a pilot test; construct validity was evaluated using an exploratory factor analysis; and convergent validity was assessed using six scales. Cronbach's α internal consistency and test-retest reliability were used to determine the reliability of the scales. RESULTS: 231 women responded to the 28-item scale. The BCSAS showed good reliability, with α = 0.897. Seven factors emerged: concealment (α = 0.765), disturbance (α = 0.772), internalized stigma (α = 0.750), aesthetics (α = 0.779), course (α = 0.599), danger (α = 0.502), and origin (α = 0.350). The test-retest reliability was 0.830 (p < 0.001). Significant correlation was observed with event centrality (r = 0.701), anxiety-depression (r = 0.668), shame (r = 0.645), guilt (r = 0.524), and quality of life (r = -0.545). CONCLUSIONS: The BCSAS is a reliable and valid measure of stigma in women with breast cancer and its survivors. It could be useful for detecting stigma risk and establishing psychotherapeutic and care priorities.

Predicted clinical and economic burden associated with reduction in access to acute coronary interventional care during the COVID-19 lockdown in two European countries.

AIMS: As a consequence of untimely or missed revascularization of ST-elevation myocardial infarction (STEMI) patients during the COVID-19 pandemic, many patients died at home or survived with serious sequelae, resulting in potential long-term worse prognosis and related health-economic implications.This analysis sought to predict long-term health outcomes [survival and quality-adjusted life-years (QALYs)] and cost of reduced treatment of STEMIs occurring during the first COVID-19 lockdown. METHODS AND RESULTS: Using a Markov decision-analytic model, we incorporated probability of hospitalization, timeliness of PCI, and projected long-term survival and cost (including societal costs) of mortality and morbidity, for STEMI occurring during the first UK and Spanish lockdowns, comparing them with expected pre-lockdown outcomes for an equivalent patient group.STEMI patients during the first UK lockdown were predicted to lose an average of 1.55 life-years and 1.17 QALYs compared with patients presenting with a STEMI pre-pandemic. Based on an annual STEMI incidence of 49 332 cases, the total additional lifetime costs calculated at the population level were £36.6 million (€41.3 million), mainly driven by costs of work absenteeism. Similarly in Spain, STEMI patients during the lockdown were expected to survive 2.03 years less than pre-pandemic patients, with a corresponding reduction in projected QALYs (-1.63). At the population level, reduced PCI access would lead to additional costs of €88.6 million. CONCLUSION: The effect of a 1-month lockdown on STEMI treatment led to a reduction in survival and QALYs compared to the pre-pandemic era. Moreover, in working-age patients, untimely revascularization led to adverse prognosis, affecting societal productivity and therefore considerably increasing societal costs.

Nursing evaluation of pediatric preoperative anxiety: a qualitative study / Avaliação de enfermagem da ansiedade pré-operatória pediátrica: um estudo qualitativo? / Evaluación enfermera de la ansiedad prequirúrgica pediátrica: estudio cualitativo

Abstract Objective: to explore and describe how perioperative nurses assess and interpret the child's behavior before entering the operating room, identifying the strategies they use to reduce anxiety and the proposals for improvements. Method: descriptive qualitative study using semi-structured interviews and participant observation of daily routines. Thematic analysis of data. This study follows the recommended criteria for publication of articles of the qualitative methodology Consolidated Criteria for Reporting Qualitative Research. Results: four topics emerged from the data: a) assessment of anxiety or close communication with the child and their family; b) evaluating what was observed; c) managing anxiety and d) improving the assessment or proposals for improvements in daily practice. Conclusion: nurses assess anxiety in their daily practice through observation using their clinical judgment. The nurse's experience is decisive for the appropriate assessment of the preoperative anxiety in child. Insufficient time between waiting and entering the operating room, lack of information from child and their parents about the surgical procedure, and parental anxiety make it difficult to assess and properly manage anxiety.

Resumo Objetivo: explorar e descrever como as enfermeiras perioperatórias avaliam e interpretam o comportamento da criança antes de entrar na sala de cirurgia, identificando as estratégias que utilizam para minimizar a ansiedade e as propostas de melhoria. Método: estudo qualitativo descritivo utilizando entrevistas semiestruturadas e observação participante das rotinas diárias. Análise temática dos dados. O estudo segue os critérios recomendados para publicação de artigos da metodologia qualitativa Consolidated Criteria for Reporting Qualitative Research. Resultados: quatro temas emergiram dos dados: a) avaliação da ansiedade ou comunicação próxima com a criança e sua família; b) analisando o que foi observado; c) controlando a ansiedade e d) melhorando a avaliação ou propostas de melhoria na prática diária. Conclusão: as enfermeiras avaliam a ansiedade em sua prática diária por meio da observação e usando julgamento clínico. A experiência da enfermeira é decisiva na avaliação adequada da ansiedade pré-operatória da criança. A falta de tempo entre a espera e o momento de entrar na sala de cirurgia, a escassez de informação que a criança e os pais têm sobre o processo cirúrgico e a ansiedade dos pais, dificultam a avaliação e o controle adequado da ansiedade.

Resumen Objetivo: explorar y describir cómo las enfermeras perioperatorias evalúan e interpretan el comportamiento del niño antes de entrar a quirófano, identificando las estrategias que utilizan para minimizar la ansiedad y las propuestas de mejora. Método: estudio cualitativo descriptivo mediante entrevistas semiestructuradas y observación participante de las rutinas diarias. Análisis temático de los datos. El estudio sigue las recomendaciones de criterios para la publicación de artículos de metodología cualitativa Consolidated Criteria for Reporting Qualitative Research. Resultados: cuatro temas surgieron de los datos: a) evaluación de la ansiedad o comunicación estrecha con el niño y su familia; b) valorando lo observado; c) manejando la ansiedad y d) mejorando la evaluación o propuestas de mejora para la práctica diaria. Conclusión: enfermeras evalúan la ansiedad en su práctica diaria de forma observacional utilizando el juicio clínico. La experiencia de la enfermera es determinante en la adecuada evaluación de la ansiedad prequirúrgica del niño. La falta de tiempo entre la espera y el momento de entrar a quirófano, la mala información que tiene el niño y los padres sobre el proceso quirúrgico y la ansiedad de los padres dificultan la evaluación y el manejo correcto de la ansiedad.

Effect of different types of supervised exercise programs on cardiorespiratory and muscular fitness, pain, fatigue, mental health and inflammatory and oxidative stress biomarkers in older patients with post-COVID-19 sequelae "EJerSA-COVID-19": a randomized controlled trial.

BACKGROUND: Many patients with COVID-19 present the so-called post-acute sequelae of COVID-19 such as fatigue, post-stress discomfort, dyspnea, headache, pain mental impairment, incapacity to perform daily physical tasks ant exercise intolerance. This study aims to investigate the effects of different exercise programs on physical and mental fitness, physical condition and biomarkers of the immune system and oxidative stress in older patients with post-COVID-19 sequelae. METHODS: The sample will be made up of 120 eligible participants, over the age of 60 years who have had COVID-19 disease and are survivors and present persistent COVID-19 symptomatology diagnosed by the corresponding physician. The participants will be randomly assigned to the experimental groups: supervised endurance group (SEG, n = 30), supervised strength group (SSG, n = 30), supervised concurrent group (SCG, n = 30), which will perform the corresponding exercise program 3 days a week compared to the control group (CG, n = 30), which will not carry out a supervised exercise program. The design of this project will include measurements of four relevant dimensions; 1) Cardiorespiratory fitness; 2) Muscle fitness; 3) Pain and mental health; and 4) Biomarkers of inflammation and oxidative stress. CONCLUSIONS: The results of this study will provide insights into the effects of different exercise programs on physical and mental fitness, physical condition and biomarkers of the immune system and oxidative stress in older patients with post-COVID-19 sequelae. These findings may be the basis for the formulation of health plans and rehabilitation programs that allow healthy aging and a reduction in the associated morbidity in patients with post-COVID-19 sequelae. TRIAL REGISTRATION: NCT05848518. Registered on May 8, 2023.

Intratumoral co-injection of NK cells and NKG2A-neutralizing monoclonal antibodies.

NK-cell reactivity against cancer is conceivably suppressed in the tumor microenvironment by the interaction of the inhibitory receptor NKG2A with the non-classical MHC-I molecules HLA-E in humans or Qa-1b in mice. We found that intratumoral delivery of NK cells attains significant therapeutic effects only if co-injected with anti-NKG2A and anti-Qa-1b blocking monoclonal antibodies against solid mouse tumor models. Such therapeutic activity was contingent on endogenous CD8 T cells and type-1 conventional dendritic cells (cDC1). Moreover, the anti-tumor effects were enhanced upon combination with systemic anti-PD-1 mAb treatment and achieved partial abscopal efficacy against distant non-injected tumors. In xenografted mice bearing HLA-E-expressing human cancer cells, intratumoral co-injection of activated allogeneic human NK cells and clinical-grade anti-NKG2A mAb (monalizumab) synergistically achieved therapeutic effects. In conclusion, these studies provide evidence for the clinical potential of intratumoral NK cell-based immunotherapies that exert their anti-tumor efficacy as a result of eliciting endogenous T-cell responses.

A novel molecular class that recruits HDAC/MECP2 complexes to PU.1 motifs reduces neuroinflammation.

Pervasive neuroinflammation occurs in many neurodegenerative diseases, including Alzheimer's disease (AD). SPI1/PU.1 is a transcription factor located at a genome-wide significant AD-risk locus and its reduced expression is associated with delayed onset of AD. We analyzed single-cell transcriptomic datasets from microglia of human AD patients and found an enrichment of PU.1-binding motifs in the differentially expressed genes. In hippocampal tissues from transgenic mice with neurodegeneration, we found vastly increased genomic PU.1 binding. We then screened for PU.1 inhibitors using a PU.1 reporter cell line and discovered A11, a molecule with anti-inflammatory efficacy and nanomolar potency. A11 regulated genes putatively by recruiting a repressive complex containing MECP2, HDAC1, SIN3A, and DNMT3A to PU.1 motifs, thus representing a novel mechanism and class of molecules. In mouse models of AD, A11 ameliorated neuroinflammation, loss of neuronal integrity, AD pathology, and improved cognitive performance. This study uncovers a novel class of anti-inflammatory molecules with therapeutic potential for neurodegenerative disorders.

Outbreaks by Klebsiella oxytoca in neonatal intensive care units: Analysis of an outbreak in a tertiary hospital and systematic review.

OBJECTIVE: Klebsiella oxytoca can cause nosocomial infections, affecting vulnerable newborns. There are few studies describing nosocomial outbreaks in the neonatal intensive care units (NICU). In this study, a systematic review of the literature was carried out to know the main characteristics of these outbreaks and the evolution of one is described. METHODS: We conducted a systematic review in the Medline database up to July 2022, and present a descriptive study of an outbreak with 21 episodes in the NICU of a tertiary hospital, between September 2021 and January 2022. RESULTS: 9 articles met the inclusion criteria. The duration of outbreaks was found to be variable, of which 4 (44.4%) lasted for a year or more. Colonization (69%) was more frequent than infections (31%) and the mortality rate was 22.4%. In studies describing sources, the most frequent was the environmental origin (57.1%). In our outbreak there were 15 colonizations and 6 infections. The infections were mild conjunctivitis without sequelae. Molecular typing analysis made it possible to detect 4 different clusters. CONCLUSIONS: There is an important variability in the evolution and results of the published outbreaks, highlighting a greater number of colonized, use of PFGE (pulsed-field gel electrophoresis) techniques for molecular typing and implementation of control measures. Finally, we describe an outbreak in which 21 neonates were affected with mild infections, resolved without sequelae and whose control measures were effective.

Intratumoral neoadjuvant immunotherapy based on the BO-112 viral RNA mimetic.

BO-112 is a poly I:C-based viral mimetic that exerts anti-tumor efficacy when intratumorally delivered in mouse models. Intratumoral BO-112 synergizes in mice with systemic anti-PD-1 mAbs and this combination has attained efficacy in PD1-refractory melanoma patients. We sought to evaluate the anti-tumor efficacy of BO-112 pre-surgically applied in neoadjuvant settings to mouse models. We have observed that repeated intratumoral injections of BO-112 prior to surgical excision of the primary tumor significantly reduced tumor metastasis from orthotopically implanted 4T1-derived tumors and subcutaneous MC38-derived tumors in mice. Such effects were enhanced when combined with systemic anti-PD-1 mAb. The anti-tumor efficacy of this neoadjuvant immunotherapy approach depended on the presence of antigen-specific effector CD8 T cells and cDC1 antigen-presenting cells. Since BO-112 has been successful in phase-two clinical trials for metastatic melanoma, these results provide a strong rationale for translating this pre-surgical strategy into clinical settings, especially in combination with standard-of-care checkpoint inhibitors.

Nursing evaluation of pediatric preoperative anxiety: a qualitative study.

OBJECTIVE: to explore and describe how perioperative nurses assess and interpret the child's behavior before entering the operating room, identifying the strategies they use to reduce anxiety and the proposals for improvements. METHOD: descriptive qualitative study using semi-structured interviews and participant observation of daily routines. Thematic analysis of data. This study follows the recommended criteria for publication of articles of the qualitative methodology Consolidated Criteria for Reporting Qualitative Research. RESULTS: four topics emerged from the data: a) assessment of anxiety or close communication with the child and their family; b) evaluating what was observed; c) managing anxiety and d) improving the assessment or proposals for improvements in daily practice. CONCLUSION: nurses assess anxiety in their daily practice through observation using their clinical judgment. The nurse's experience is decisive for the appropriate assessment of the preoperative anxiety in child. Insufficient time between waiting and entering the operating room, lack of information from child and their parents about the surgical procedure, and parental anxiety make it difficult to assess and properly manage anxiety.

Monocyte-derived cells invade brain parenchyma and amyloid plaques in human Alzheimer's disease hippocampus.

Microglia are brain-resident myeloid cells and play a major role in the innate immune responses of the CNS and the pathogenesis of Alzheimer's disease (AD). However, the contribution of nonparenchymal or brain-infiltrated myeloid cells to disease progression remains to be demonstrated. Here, we show that monocyte-derived cells (MDC) invade brain parenchyma in advanced stages of AD continuum using transcriptional analysis and immunohistochemical characterization in post-mortem human hippocampus. Our findings demonstrated that a high proportion (60%) of demented Braak V-VI individuals was associated with up-regulation of genes rarely expressed by microglial cells and abundant in monocytes, among which stands the membrane-bound scavenger receptor for haptoglobin/hemoglobin complexes or Cd163. These Cd163-positive MDC invaded the hippocampal parenchyma, acquired a microglial-like morphology, and were located in close proximity to blood vessels. Moreover, and most interesting, these invading monocytes infiltrated the nearby amyloid plaques contributing to plaque-associated myeloid cell heterogeneity. However, in aged-matched control individuals with hippocampal amyloid pathology, no signs of MDC brain infiltration or plaque invasion were found. The previously reported microglial degeneration/dysfunction in AD hippocampus could be a key pathological factor inducing MDC recruitment. Our data suggest a clear association between MDC infiltration and endothelial activation which in turn may contribute to damage of the blood brain barrier integrity. The recruitment of monocytes could be a consequence rather than the cause of the severity of the disease. Whether monocyte infiltration is beneficial or detrimental to AD pathology remains to be fully elucidated. These findings open the opportunity to design targeted therapies, not only for microglia but also for the peripheral immune cell population to modulate amyloid pathology and provide a better understanding of the immunological mechanisms underlying the progression of AD.

The role of mitochondrial genome abundance in Alzheimer's disease.

Mitochondrial dysfunction is an early and prominent feature of Alzheimer's disease (AD), with impaired energy metabolism preceding the onset of clinical symptoms. Here we propose an update to the mitochondrial dysfunction hypothesis of AD based on recent results examining the role of mitochondrial genome abundance in AD. In a large post mortem study, we show that lower brain mitochondrial genome abundance is associated with a greater odds of AD neuropathological change and worse cognitive performance. We hypothesize that lower mitochondrial genome abundance impairs mitochondrial function by reducing mitochondrial bioenergetics, thereby impacting neuronal and glial cell function. However, it remains to be determined if mitochondrial dysfunction causes, mediates, or is a by-product of AD pathogenesis. Additional support for this hypothesis will be generated by linking peripheral blood mitochondrial genome abundance to AD and establishing clinical trials of compounds that upregulate total mitochondrial genome abundance or boost mitochondrial mass.

Microglial efferocytosis: Diving into the Alzheimer's disease gene pool.

Genome-wide association studies and functional genomics studies have linked specific cell types, genes, and pathways to Alzheimer's disease (AD) risk. In particular, AD risk alleles primarily affect the abundance or structure, and thus the activity, of genes expressed in macrophages, strongly implicating microglia (the brain-resident macrophages) in the etiology of AD. These genes converge on pathways (endocytosis/phagocytosis, cholesterol metabolism, and immune response) with critical roles in core macrophage functions such as efferocytosis. Here, we review these pathways, highlighting relevant genes identified in the latest AD genetics and genomics studies, and describe how they may contribute to AD pathogenesis. Investigating the functional impact of AD-associated variants and genes in microglia is essential for elucidating disease risk mechanisms and developing effective therapeutic approaches.

Depletion of Conventional Type-1 Dendritic Cells in Established Tumors Suppresses Immunotherapy Efficacy.

The ability of conventional type-1 dendritic cells (cDC1) to cross-present tumor antigens to CD8+ T cells is critical for the induction of antitumor CTLs. Mice that are constitutively deficient in cDC1 cells have been reported to fail to respond to immunotherapy strategies based on checkpoint inhibitors. However, further work is needed to clarify the precise time during immunotherapy treatment that cDC1 cells are required for the beneficial effect of treatment. Here, we used a refined XCR1-DTR-Venus transgenic mouse model to acutely deplete cDC1 cells and trace their behavior using intravital microscopy. Diphtheria toxin-mediated cDC1 depletion prior to immunotherapy treatment with anti-PD-1 and/or anti-CD137 immunostimulatory mAbs completely ablated antitumor efficacy. The efficacy of adoptive T-cell therapy was also hampered by prior cDC1 depletion. After the onset of immunotherapy treatment, depletion of cDC1s only moderately reduced the therapeutic efficacy of anti-PD-1 and anti-CD137 mAbs. Intravital microscopy of liver-engrafted tumors revealed changes in the intratumoral behavior of cDC1 cells in mice receiving immunotherapy, and treatment with diphtheria toxin to deplete cDC1s impaired tumor T-cell infiltration and function. These results reveal that the functional integrity of the cDC1 compartment is required at the onset of various immunotherapies to successfully treat established tumors. SIGNIFICANCE: These findings reveal the intratumoral behavior of cDC1 dendritic cells in transgenic mouse models and demonstrate that the efficacy of immunotherapy regimens is precluded by elimination of these cells.

Treatment of Bolivian Leishmania braziliensis Cutaneous and Mucosal Leishmaniasis.

Although infection with Leishmania braziliensis is perhaps the key reason to treat New World cutaneous leishmaniasis (CL) and mucosal leishmaniasis (ML), the total literature contains relatively few reported cases. With the aim of supplementing the meager clinical information available, we searched the records of Jorochito (Dermatology) Hospital, Bolivia, for the years 1999-2020 and identified treatment records for 1,696 naive CL patients and 355 naive ML patients. Because follow-up was poor for this real-world treatment experience in the developing world, only 255 CL patients (15%) and 114 ML patients (32%) attended follow-up at Hospital. We therefore engaged in an Active Search for "lost" patients, located a further 542 CL patients (32%) and 142 ML patients (44%), thus eventually accomplished follow up on 697 CL patients (41%) and 256 ML patients (72%). Granular adverse event data derived from hospital records is listed for the 902 CL and 86 ML patients administered Glucantime intramuscularly, the 401 CL and 202 ML patients administered Glucantime intravenously, and the 163 CL and 89 ML patients administered miltefosine orally. Efficacy was obtained from hospital records for patients seen at hospital and from patient recall communicated by telephone for the patients found in the Active Search. The overall CL cure rate was 508 of 697 CL patients (73%) with follow-up: intramuscular Glucantime-196/293 (67%); intravenous Glucantime-90/126 (71%); intralesional Glucantime-34/54 (63%); oral miltefosine-52/69 (75%). The overall ML cure rate was 161 of 256 ML patients (63%) with follow-up: intramuscular Glucantime-26/48 (54%); intravenous Glucantime-66/104 (63%); intravenous amphotericin B deoxycholate-19/35 (54%); oral miltefosine-50/71 (70%). We offer this extensive adverse event and efficacy experience as useful guides for clinicians presented with a L. braziliensis infection. The cure rates also illustrate the quandary of New World CL and ML chemotherapy: sufficiently high to be useful but nevertheless needing augmentation with new agents.

Intratumoral co-injection of the poly I:C-derivative BO-112 and a STING agonist synergize to achieve local and distant anti-tumor efficacy.

BACKGROUND: BO-112 is a nanoplexed form of polyinosinic:polycytidylic acid that acting on toll-like receptor 3 (TLR3), melanoma differentiation-associated protein 5 (MDA5) and protein kinase RNA-activated (PKR) elicits rejection of directly injected transplanted tumors, but has only modest efficacy against distant untreated tumors. Its clinical activity has also been documented in early phase clinical trials. The 5,6-dimethylxanthenone-4-acetic acid (DMXAA) stimulator of interferon genes (STING) agonist shows a comparable pattern of efficacy when used via intratumoral injections. METHODS: Mice subcutaneously engrafted with bilateral MC38 and B16.OVA-derived tumors were treated with proinflammatory immunotherapy agents known to be active when intratumorally delivered. The combination of BO-112 and DMXAA was chosen given its excellent efficacy and the requirements for antitumor effects were studied on selective depletion of immune cell types and in gene-modified mouse strains lacking basic leucine zipper ATF-like transcription factor 3 (BATF3), interferon-α/ß receptor (IFNAR) or STING. Spatial requirements for the injections were studied in mice bearing three tumor lesions. RESULTS: BO-112 and DMXAA when co-injected in one of the lesions of mice bearing concomitant bilateral tumors frequently achieved complete local and distant antitumor efficacy. Synergistic effects were contingent on CD8 T cell lymphocytes and dependent on conventional type 1 dendritic cells, responsiveness to type I interferon (IFN) and STING function in the tumor-bearing host. Efficacy was preserved even if BO-112 and DMXAA were injected in separate lesions in a manner able to control another untreated third-party tumor. Efficacy could be further enhanced on concurrent PD-1 blockade. CONCLUSION: Clinically feasible co-injections of BO-112 and a STING agonist attain synergistic efficacy able to eradicate distant untreated tumor lesions.

Should We Open Fire on Microglia? Depletion Models as Tools to Elucidate Microglial Role in Health and Alzheimer's Disease.

Microglia play a critical role in both homeostasis and disease, displaying a wide variety in terms of density, functional markers and transcriptomic profiles along the different brain regions as well as under injury or pathological conditions, such as Alzheimer's disease (AD). The generation of reliable models to study into a dysfunctional microglia context could provide new knowledge towards the contribution of these cells in AD. In this work, we included an overview of different microglial depletion approaches. We also reported unpublished data from our genetic microglial depletion model, Cx3cr1CreER/Csf1rflx/flx, in which we temporally controlled microglia depletion by either intraperitoneal (acute model) or oral (chronic model) tamoxifen administration. Our results reported a clear microglial repopulation, then pointing out that our model would mimic a context of microglial replacement instead of microglial dysfunction. Next, we evaluated the origin and pattern of microglial repopulation. Additionally, we also reviewed previous works assessing the effects of microglial depletion in the progression of Aß and Tau pathologies, where controversial data are found, probably due to the heterogeneous and time-varying microglial phenotypes observed in AD. Despite that, microglial depletion represents a promising tool to assess microglial role in AD and design therapeutic strategies.

Annexin A1 restores cerebrovascular integrity concomitant with reduced amyloid-ß and tau pathology.

Alzheimer's disease, characterized by brain deposits of amyloid-ß plaques and neurofibrillary tangles, is also linked to neurovascular dysfunction and blood-brain barrier breakdown, affecting the passage of substances into and out of the brain. We hypothesized that treatment of neurovascular alterations could be beneficial in Alzheimer's disease. Annexin A1 (ANXA1) is a mediator of glucocorticoid anti-inflammatory action that can suppress microglial activation and reduce blood-brain barrier leakage. We have reported recently that treatment with recombinant human ANXA1 (hrANXA1) reduced amyloid-ß levels by increased degradation in neuroblastoma cells and phagocytosis by microglia. Here, we show the beneficial effects of hrANXA1 in vivo by restoring efficient blood-brain barrier function and decreasing amyloid-ß and tau pathology in 5xFAD mice and Tau-P301L mice. We demonstrate that young 5xFAD mice already suffer cerebrovascular damage, while acute pre-administration of hrANXA1 rescued the vascular defects. Interestingly, the ameliorated blood-brain barrier permeability in young 5xFAD mice by hrANXA1 correlated with reduced brain amyloid-ß load, due to increased clearance and degradation of amyloid-ß by insulin degrading enzyme (IDE). The systemic anti-inflammatory properties of hrANXA1 were also observed in 5xFAD mice, increasing IL-10 and reducing TNF-α expression. Additionally, the prolonged treatment with hrANXA1 reduced the memory deficits and increased synaptic density in young 5xFAD mice. Similarly, in Tau-P301L mice, acute hrANXA1 administration restored vascular architecture integrity, affecting the distribution of tight junctions, and reduced tau phosphorylation. The combined data support the hypothesis that blood-brain barrier breakdown early in Alzheimer's disease can be restored by hrANXA1 as a potential therapeutic approach.

Hypoxia compromises the mitochondrial metabolism of Alzheimer's disease microglia via HIF1.

Genetic Alzheimer's disease (AD) risk factors associate with reduced defensive amyloid ß plaque-associated microglia (AßAM), but the contribution of modifiable AD risk factors to microglial dysfunction is unknown. In AD mouse models, we observe concomitant activation of the hypoxia-inducible factor 1 (HIF1) pathway and transcription of mitochondrial-related genes in AßAM, and elongation of mitochondria, a cellular response to maintain aerobic respiration under low nutrient and oxygen conditions. Overactivation of HIF1 induces microglial quiescence in cellulo, with lower mitochondrial respiration and proliferation. In vivo, overstabilization of HIF1, either genetically or by exposure to systemic hypoxia, reduces AßAM clustering and proliferation and increases Aß neuropathology. In the human AD hippocampus, upregulation of HIF1α and HIF1 target genes correlates with reduced Aß plaque microglial coverage and an increase of Aß plaque-associated neuropathology. Thus, hypoxia (a modifiable AD risk factor) hijacks microglial mitochondrial metabolism and converges with genetic susceptibility to cause AD microglial dysfunction.