A MicroRNA Linking Human Positive Selection and Metabolic Disorders.

Positive selection in Europeans at the 2q21.3 locus harboring the lactase gene has been attributed to selection for the ability of adults to digest milk to survive famine in ancient times. However, the 2q21.3 locus is also associated with obesity and type 2 diabetes in humans, raising the possibility that additional genetic elements in the locus may have contributed to evolutionary adaptation to famine by promoting energy storage, but which now confer susceptibility to metabolic diseases. We show here that the miR-128-1 microRNA, located at the center of the positively selected locus, represents a crucial metabolic regulator in mammals. Antisense targeting and genetic ablation of miR-128-1 in mouse metabolic disease models result in increased energy expenditure and amelioration of high-fat-diet-induced obesity and markedly improved glucose tolerance. A thrifty phenotype connected to miR-128-1-dependent energy storage may link ancient adaptation to famine and modern metabolic maladaptation associated with nutritional overabundance.

Negative feedback control of neuronal activity by microglia.

Microglia, the brain's resident macrophages, help to regulate brain function by removing dying neurons, pruning non-functional synapses, and producing ligands that support neuronal survival1. Here we show that microglia are also critical modulators of neuronal activity and associated behavioural responses in mice. Microglia respond to neuronal activation by suppressing neuronal activity, and ablation of microglia amplifies and synchronizes the activity of neurons, leading to seizures. Suppression of neuronal activation by microglia occurs in a highly region-specific fashion and depends on the ability of microglia to sense and catabolize extracellular ATP, which is released upon neuronal activation by neurons and astrocytes. ATP triggers the recruitment of microglial protrusions and is converted by the microglial ATP/ADP hydrolysing ectoenzyme CD39 into AMP; AMP is then converted into adenosine by CD73, which is expressed on microglia as well as other brain cells. Microglial sensing of ATP, the ensuing microglia-dependent production of adenosine, and the adenosine-mediated suppression of neuronal responses via the adenosine receptor A1R are essential for the regulation of neuronal activity and animal behaviour. Our findings suggest that this microglia-driven negative feedback mechanism operates similarly to inhibitory neurons and is essential for protecting the brain from excessive activation in health and disease.

Ecological divergence of wild birds drives avian influenza spillover and global spread.

The diversity of influenza A viruses (IAV) is primarily hosted by two highly divergent avian orders: Anseriformes (ducks, swans and geese) and Charadriiformes (gulls, terns and shorebirds). Studies of IAV have historically focused on Anseriformes, specifically dabbling ducks, overlooking the diversity of hosts in nature, including gull and goose species that have successfully adapted to human habitats. This study sought to address this imbalance by characterizing spillover dynamics and global transmission patterns of IAV over 10 years at greater taxonomic resolution than previously considered. Furthermore, the circulation of viral subtypes in birds that are either host-adapted (low pathogenic H13, H16) or host-generalist (highly pathogenic avian influenza-HPAI H5) provided a unique opportunity to test and extend models of viral evolution. Using Bayesian phylodynamic modelling we uncovered a complex transmission network that relied on ecologically divergent bird hosts. The generalist subtype, HPAI H5 was driven largely by wild geese and swans that acted as a source for wild ducks, gulls, land birds, and domestic geese. Gulls were responsible for moving HPAI H5 more rapidly than any other host, a finding that may reflect their long-distance, pelagic movements and their immuno-naïve status against this subtype. Wild ducks, long viewed as primary hosts for spillover, occupied an optimal space for viral transmission, contributing to geographic expansion and rapid dispersal of HPAI H5. Evidence of inter-hemispheric dispersal via both the Pacific and Atlantic Rims was detected, supporting surveillance at high latitudes along continental margins to achieve early detection. Both neutral (geographic expansion) and non-neutral (antigenic selection) evolutionary processes were found to shape subtype evolution which manifested as unique geographic hotspots for each subtype at the global scale. This study reveals how a diversity of avian hosts contribute to viral spread and spillover with the potential to improve surveillance in an era of rapid global change.

Neurologic complications in patients receiving aortic versus subclavian versus femoral arterial cannulation for post-cardiotomy extracorporeal life support: results of the PELS observational multicenter study.

BACKGROUND: Cerebral perfusion may change depending on arterial cannulation site and may affect the incidence of neurologic adverse events in post-cardiotomy extracorporeal life support (ECLS). The current study compares patients' neurologic outcomes with three commonly used arterial cannulation strategies (aortic vs. subclavian/axillary vs. femoral artery) to evaluate if each ECLS configuration is associated with different rates of neurologic complications. METHODS: This retrospective, multicenter (34 centers), observational study included adults requiring post-cardiotomy ECLS between January 2000 and December 2020 present in the Post-Cardiotomy Extracorporeal Life Support (PELS) Study database. Patients with Aortic, Subclavian/Axillary and Femoral cannulation were compared on the incidence of a composite neurological end-point (ischemic stroke, cerebral hemorrhage, brain edema). Secondary outcomes were overall in-hospital mortality, neurologic complications as cause of in-hospital death, and post-operative minor neurologic complications (seizures). Association between cannulation and neurological outcomes were investigated through linear mixed-effects models. RESULTS: This study included 1897 patients comprising 26.5% Aortic (n = 503), 20.9% Subclavian/Axillary (n = 397) and 52.6% Femoral (n = 997) cannulations. The Subclavian/Axillary group featured a more frequent history of hypertension, smoking, diabetes, previous myocardial infarction, dialysis, peripheral artery disease and previous stroke. Neuro-monitoring was used infrequently in all groups. Major neurologic complications were more frequent in Subclavian/Axillary (Aortic: n = 79, 15.8%; Subclavian/Axillary: n = 78, 19.6%; Femoral: n = 118, 11.9%; p < 0.001) also after mixed-effects model adjustment (OR 1.53 [95% CI 1.02-2.31], p = 0.041). Seizures were more common in Subclavian/Axillary (n = 13, 3.4%) than Aortic (n = 9, 1.8%) and Femoral cannulation (n = 12, 1.3%, p = 0.036). In-hospital mortality was higher after Aortic cannulation (Aortic: n = 344, 68.4%, Subclavian/Axillary: n = 223, 56.2%, Femoral: n = 587, 58.9%, p < 0.001), as shown by Kaplan-Meier curves. Anyhow, neurologic cause of death (Aortic: n = 12, 3.9%, Subclavian/Axillary: n = 14, 6.6%, Femoral: n = 28, 5.0%, p = 0.433) was similar. CONCLUSIONS: In this analysis of the PELS Study, Subclavian/Axillary cannulation was associated with higher rates of major neurologic complications and seizures. In-hospital mortality was higher after Aortic cannulation, despite no significant differences in incidence of neurological cause of death in these patients. These results encourage vigilance for neurologic complications and neuromonitoring use in patients on ECLS, especially with Subclavian/Axillary cannulation.

Preoperative anatomical landmarks and longitudinal HeartMate 3 pump position in X-rays: Relevance for adverse events.

BACKGROUND: Left ventricular assist device (LVAD) malposition has been linked to hemocompatibility-related adverse events (HRAEs). This study aimed to identify preoperative anatomical landmarks and postoperative pump position, associated with HRAEs during LVAD support. METHODS: Pre- and postoperative chest X-ray measures (≤14 days pre-implantation, first postoperative standing, 6, 12, 18, and 24 months post-implantation) were analyzed for their association with HRAEs over 24 months in 33 HeartMate 3 (HM3) patients (15.2% female, age 66 (9.5) years). RESULTS: HM3 patients with any HRAE showed significantly lower preoperative distances between left ventricle and thoracic outline (dLVT) (25.3 ± 10.2 mm vs. 40.3 ± 15.5 mm, p = 0.004). A ROC-derived cutoff dLVT ≤ 29.2 mm provided 85.7% sensitivity and 72.2% specificity predicting any HRAE during HM3 support (76.2% (>29.2 mm) vs. 16.7% (≤29.2 mm) freedom from HRAE, p < 0.001) and significant differences in cardiothoracic ratio (0.58 ± 0.04 vs. 0.62 ± 0.04, p = 0.045). Postoperative X-rays indicated lower pump depths in patients with ischemic strokes (9.1 ± 16.2 mm vs. 38.0 ± 18.5 mm, p = 0.007), reduced freedom from any neurological event (pump depth ≤ 28.7 mm: 45.5% vs. 94.1%, p = 0.004), and a significant correlation between pump depth and inflow cannula angle (r = 0.66, p < 0.001). Longitudinal changes were observed in heart-pump width (F(4,60) = 5.61, p < 0.001). CONCLUSION: Preoperative X-ray markers are associated with postoperative HRAE occurrence. Applying this knowledge in clinical practice may enhance risk stratification, guide therapy optimization, and improve HM3 recipient management.

Post-cardiotomy extracorporeal life support: A cohort of cannulation in the general ward.

OBJECTIVES: Post-cardiotomy extracorporeal life support (ECLS) cannulation might occur in a general post-operative ward due to emergent conditions. Its characteristics have been poorly reported and investigated This study investigates the characteristics and outcomes of adult patients receiving ECLS cannulation in a general post-operative cardiac ward. METHODS: The Post-cardiotomy Extracorporeal Life Support (PELS) is a retrospective (2000-2020), multicenter (34 centers), observational study including adult patients who required ECLS for post-cardiotomy shock. This PELS sub-analysis analyzed patients´ characteristics, in-hospital outcomes, and long-term survival in patients cannulated for veno-arterial ECLS in the general ward, and further compared in-hospital survivors and non-survivors. RESULTS: The PELS study included 2058 patients of whom 39 (1.9%) were cannulated in the general ward. Most patients underwent isolated coronary bypass grafting (CABG, n = 15, 38.5%) or isolated non-CABG operations (n = 20, 51.3%). The main indications to initiate ECLS included cardiac arrest (n = 17, 44.7%) and cardiogenic shock (n = 14, 35.9%). ECLS cannulation occurred after a median time of 4 (2-7) days post-operatively. Most patients' courses were complicated by acute kidney injury (n = 23, 59%), arrhythmias (n = 19, 48.7%), and postoperative bleeding (n = 20, 51.3%). In-hospital mortality was 84.6% (n = 33) with persistent heart failure (n = 11, 28.2%) as the most common cause of death. No peculiar differences were observed between in-hospital survivors and nonsurvivors. CONCLUSIONS: This study demonstrates that ECLS cannulation due to post-cardiotomy emergent adverse events in the general ward is rare, mainly occurring in preoperative low-risk patients and after a postoperative cardiac arrest. High complication rates and low in-hospital survival require further investigations to identify patients at risk for such a complication, optimize resources, enhance intervention, and improve outcomes.

A translational profiling approach for the molecular characterization of CNS cell types.

The cellular heterogeneity of the brain confounds efforts to elucidate the biological properties of distinct neuronal populations. Using bacterial artificial chromosome (BAC) transgenic mice that express EGFP-tagged ribosomal protein L10a in defined cell populations, we have developed a methodology for affinity purification of polysomal mRNAs from genetically defined cell populations in the brain. The utility of this approach is illustrated by the comparative analysis of four types of neurons, revealing hundreds of genes that distinguish these four cell populations. We find that even two morphologically indistinguishable, intermixed subclasses of medium spiny neurons display vastly different translational profiles and present examples of the physiological significance of such differences. This genetically targeted translating ribosome affinity purification (TRAP) methodology is a generalizable method useful for the identification of molecular changes in any genetically defined cell type in response to genetic alterations, disease, or pharmacological perturbations.

Single Donor Infusion of S-Nitroso-Human-Serum-Albumin Attenuates Cardiac Isograft Fibrosis and Preserves Myocardial Micro-RNA-126-3p in a Murine Heterotopic Heart Transplant Model.

Objectives: Cold ischemia and subsequent reperfusion injury are non-immunologic cornerstones in the development of graft injury after heart transplantation. The nitric oxide donor S-nitroso-human-serum-albumin (S-NO-HSA) is known to attenuate myocardial ischemia-reperfusion (I/R)-injury. We assessed whether donor preservation with S-NO-HSA affects isograft injury and myocardial expression of GATA2 as well as miR-126-3p, which are considered protective against vascular and endothelial injury. Methods: Donor C57BL/6 mice received intravenous (0.1 µmol/kg/h) S-NO-HSA (n = 12), or 0.9% saline (control, n = 11) for 20 min. Donor hearts were stored in cold histidine-tryptophan-α-ketoglutarate-N solution for 12 h and underwent heterotopic, isogenic transplantation, except 5 hearts of each group, which were analysed immediately after preservation. Fibrosis was quantified and expression of GATA2 and miR-126-3p assessed by RT-qPCR after 60 days or immediately after preservation. Results: Fibrosis was significantly reduced in the S-NO-HSA group (6.47% ± 1.76 vs. 11.52% ± 2.16; p = 0.0023; 12 h-S-NO-HSA-hHTX vs. 12 h-control-hHTX). Expression of miR-126-3p was downregulated in all hearts after ischemia compared to native myocardium, but the effect was significantly attenuated when donors received S-NO-HSA (1 ± 0.27 vs. 0.33 ± 0.31; p = 0.0187; 12 h-S-NO-HSA-hHTX vs. 12 h-control-hHTX; normalized expression to U6 snRNA). Conclusion: Donor pre-treatment with S-NO-HSA lead to reduced fibrosis and preservation of myocardial miR-126-3p and GATA2 levels in murine cardiac isografts 60 days after transplantation.

Impacts of Telomeric Length, Chronic Hypoxia, Senescence, and Senescence-Associated Secretory Phenotype on the Development of Thoracic Aortic Aneurysm.

Thoracic aortic aneurysm (TAA) is an age-related and life-threatening vascular disease. Telomere shortening is a predictor of age-related diseases, and its progression is associated with premature vascular disease. The aim of the present work was to investigate the impacts of chronic hypoxia and telomeric DNA damage on cellular homeostasis and vascular degeneration of TAA. We analyzed healthy and aortic aneurysm specimens (215 samples) for telomere length (TL), chronic DNA damage, and resulting changes in cellular homeostasis, focusing on senescence and apoptosis. Compared with healthy thoracic aorta (HTA), patients with tricuspid aortic valve (TAV) showed telomere shortening with increasing TAA size, in contrast to genetically predisposed bicuspid aortic valve (BAV). In addition, TL was associated with chronic hypoxia and telomeric DNA damage and with the induction of senescence-associated secretory phenotype (SASP). TAA-TAV specimens showed a significant difference in SASP-marker expression of IL-6, NF-κB, mTOR, and cell-cycle regulators (γH2AX, Rb, p53, p21), compared to HTA and TAA-BAV. Furthermore, we observed an increase in CD163+ macrophages and a correlation between hypoxic DNA damage and the number of aortic telocytes. We conclude that chronic hypoxia is associated with telomeric DNA damage and the induction of SASP in a diseased aortic wall, promising a new therapeutic target.

Heatwave-induced synchrony within forage fish portfolio disrupts energy flow to top pelagic predators.

During the Pacific marine heatwave of 2014-2016, abundance and quality of several key forage fish species in the Gulf of Alaska were simultaneously reduced throughout the system. Capelin (Mallotus catervarius), sand lance (Ammodytes personatus), and herring (Clupea pallasii) populations were at historically low levels, and within this community abrupt declines in portfolio effects identify trophic instability at the onset of the heatwave. Although compensatory changes in age structure, size, growth or energy content of forage fish were observed to varying degrees among all these forage fish, none were able to fully mitigate adverse impacts of the heatwave, which likely included both top-down and bottom-up forcing. Notably, changes to the demographic structure of forage fish suggested size-selective removals typical of top-down regulation. At the same time, changes in zooplankton communities may have driven bottom-up regulation as copepod community structure shifted toward smaller, warm water species, and euphausiid biomass was reduced owing to the loss of cold-water species. Mediated by these impacts on the forage fish community, an unprecedented disruption of the normal pelagic food web was signaled by higher trophic level disruptions during 2015-2016, when seabirds, marine mammals, and groundfish experienced shifts in distribution, mass mortalities, and reproductive failures. Unlike decadal-scale variability underlying ecosystem regime shifts, the heatwave appeared to temporarily overwhelm the ability of the forage fish community to buffer against changes imposed by warm water anomalies, thereby eliminating any ecological advantages that may have accrued from having a suite of coexisting forage species with differing life-history compensations.

AP-1 controls the p11-dependent antidepressant response.

Selective serotonin reuptake inhibitors (SSRIs) are the most widely prescribed drugs for mood disorders. While the mechanism of SSRI action is still unknown, SSRIs are thought to exert therapeutic effects by elevating extracellular serotonin levels in the brain, and remodel the structural and functional alterations dysregulated during depression. To determine their precise mode of action, we tested whether such neuroadaptive processes are modulated by regulation of specific gene expression programs. Here we identify a transcriptional program regulated by activator protein-1 (AP-1) complex, formed by c-Fos and c-Jun that is selectively activated prior to the onset of the chronic SSRI response. The AP-1 transcriptional program modulates the expression of key neuronal remodeling genes, including S100a10 (p11), linking neuronal plasticity to the antidepressant response. We find that AP-1 function is required for the antidepressant effect in vivo. Furthermore, we demonstrate how neurochemical pathways of BDNF and FGF2, through the MAPK, PI3K, and JNK cascades, regulate AP-1 function to mediate the beneficial effects of the antidepressant response. Here we put forth a sequential molecular network to track the antidepressant response and provide a new avenue that could be used to accelerate or potentiate antidepressant responses by triggering neuroplasticity.

Effect of Poloxamer 188 vs Placebo on Painful Vaso-Occlusive Episodes in Children and Adults With Sickle Cell Disease: A Randomized Clinical Trial.

Importance: Although effective agents are available to prevent painful vaso-occlusive episodes of sickle cell disease (SCD), there are no disease-modifying therapies for ongoing painful vaso-occlusive episodes; treatment remains supportive. A previous phase 3 trial of poloxamer 188 reported shortened duration of painful vaso-occlusive episodes in SCD, particularly in children and participants treated with hydroxyurea. Objective: To reassess the efficacy of poloxamer 188 for vaso-occlusive episodes. Design, Setting, and Participants: Phase 3, randomized, double-blind, placebo-controlled, multicenter, international trial conducted from May 2013 to February 2016 that included 66 hospitals in 12 countries and 60 cities; 388 individuals with SCD (hemoglobin SS, SC, S-ß0 thalassemia, or S-ß+ thalassemia disease) aged 4 to 65 years with acute moderate to severe pain typical of painful vaso-occlusive episodes requiring hospitalization were included. Interventions: A 1-hour 100-mg/kg loading dose of poloxamer 188 intravenously followed by a 12-hour to 48-hour 30-mg/kg/h continuous infusion (n = 194) or placebo (n = 194). Main Outcomes and Measures: Time in hours from randomization to the last dose of parenteral opioids among all participants and among those younger than 16 years as a separate subgroup. Results: Of 437 participants assessed for eligibility, 388 were randomized (mean age, 15.2 years; 176 [45.4%] female), the primary outcome was available for 384 (99.0%), 15-day follow-up contacts were available for 357 (92.0%), and 30-day follow-up contacts were available for 368 (94.8%). There was no significant difference between the groups for the mean time to last dose of parenteral opioids (81.8 h for the poloxamer 188 group vs 77.8 h for the placebo group; difference, 4.0 h [95% CI, -7.8 to 15.7]; geometric mean ratio, 1.2 [95% CI, 1.0-1.5]; P = .09). Based on a significant interaction of age and treatment (P = .01), there was a treatment difference in time from randomization to last administration of parenteral opioids for participants younger than 16 years (88.7 h in the poloxamer 188 group vs 71.9 h in the placebo group; difference, 16.8 h [95% CI, 1.7-32.0]; geometric mean ratio, 1.4 [95% CI, 1.1-1.8]; P = .008). Adverse events that were more common in the poloxamer 188 group than the placebo group included hyperbilirubinemia (12.7% vs 5.2%); those more common in the placebo group included hypoxia (12.0% vs 5.3%). Conclusions and Relevance: Among children and adults with SCD, poloxamer 188 did not significantly shorten time to last dose of parenteral opioids during vaso-occlusive episodes. These findings do not support the use of poloxamer 188 for vaso-occlusive episodes. Trial Registration: ClinicalTrials.gov Identifier: NCT01737814.

Awake Implementation of Extracorporeal Life Support in Refractory Cardiogenic Shock.

Background and objectives: Extracorporeal life support (ECLS) is a widely accepted and effective strategy for use in patients presenting with refractory cardiogenic shock. Implantation in awake and non-intubated patients allows for optimized evaluation of further therapy options while avoiding potential side effects associated with the need for sedation and intubation. The aim of the study was the assessment of safety and feasibility of awake ECLS implementation and of outcomes in patients treated with this concept. Materials and Methods: We retrospectively reviewed the concept of awake ECLS implantation in 16 consecutive patients (mean age 58 ± 8 years; male: 88%; ischemic cardiomyopathy: 50%) from 02/2017 to 01/2021. Study endpoints were survival to weaning or bridging to durable support or organ replacement and development of end-organ function and hemodynamic parameters on ECLS. Results: Fourteen patients (88%) were able to be successfully transitioned to definite therapy options. ECLS support stabilized end-organ function, led to a decrease in mean lactate levels (5.3 ± 3.7 mmol/L at baseline to 1.9 ± 1.3 mmol/L 12 h after ECLS start; p = 0.01) and improved hemodynamics (median central venous pressure 20 ± 5 mmHg vs. 10 ± 2 mmHg, p = 0.001) over a median duration of two days (1-8 days IQR). Two patients (13%) died on ECLS support due to multi-organ dysfunction syndrome. Survival to discharge of initially successfully bridged or weaned patients was 64%. Conclusions: Awake ECLS implantation is feasible and safe with the key advantage of omitting or delaying general anesthesia and intubation, with their associated risks in cardiogenic-shock patients, facilitating further decision making.

Molecular-level HLA mismatch is associated with rejection and worsened graft survival in heart transplant recipients - a retrospective study.

The aim was to evaluate the association of molecular-level human leukocyte antigen (HLA) mismatching with post-transplant graft survival, rejection, and cardiac allograft vasculopathy (CAV). We retrospectively analyzed all primary cardiac transplant recipients between 01/1984-06/2016. 1167 patients fulfilled inclusion criteria and had HLA typing information available. In 312 donor-recipient pairs, typing at serological split antigen level was available. We used the Epitope MisMatch Algorithm to calculate the number of amino acid differences in antibody-verified HLA eplets (amino acid mismatch load (AAMM)) between donor and recipient. Patients with a higher HLA-DR AAMM load had inferior 1-year graft survival (hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.01-1.28). The HLA-AB AAMM load showed no impact on graft survival. In the subgroup with available split-level information, we observed an inferior graft survival for a higher HLA-DR AAMM load 3 months after transplantation (HR, 1.22; 95% CI, 1.04-1.44) and a higher risk for rejection for an increasing HLA-AB (HR, 1.70; 95% CI, 1.29-2.24) and HLA-DR (HR, 1.32; 95% CI, 1.09-1.61) AAMM load. No impact on the development of CAV was found. Molecular-level HLA mismatch analysis could serve as a tool for risk stratification after heart transplantation and might take us one step further into precision medicine.

An AUTS2-Polycomb complex activates gene expression in the CNS.

Naturally occurring variations of Polycomb repressive complex 1 (PRC1) comprise a core assembly of Polycomb group proteins and additional factors that include, surprisingly, autism susceptibility candidate 2 (AUTS2). Although AUTS2 is often disrupted in patients with neuronal disorders, the mechanism underlying the pathogenesis is unclear. We investigated the role of AUTS2 as part of a previously identified PRC1 complex (PRC1-AUTS2), and in the context of neurodevelopment. In contrast to the canonical role of PRC1 in gene repression, PRC1-AUTS2 activates transcription. Biochemical studies demonstrate that the CK2 component of PRC1-AUTS2 neutralizes PRC1 repressive activity, whereas AUTS2-mediated recruitment of P300 leads to gene activation. Chromatin immunoprecipitation followed by sequencing (ChIP-seq) demonstrated that AUTS2 regulates neuronal gene expression through promoter association. Conditional targeting of Auts2 in the mouse central nervous system (CNS) leads to various developmental defects. These findings reveal a natural means of subverting PRC1 activity, linking key epigenetic modulators with neuronal functions and diseases.

The Role of Epigenetic Mechanisms in the Regulation of Gene Expression in the Nervous System.

Neuroepigenetics is a newly emerging field in neurobiology that addresses the epigenetic mechanism of gene expression regulation in various postmitotic neurons, both over time and in response to environmental stimuli. In addition to its fundamental contribution to our understanding of basic neuronal physiology, alterations in these neuroepigenetic mechanisms have been recently linked to numerous neurodevelopmental, psychiatric, and neurodegenerative disorders. This article provides a selective review of the role of DNA and histone modifications in neuronal signal-induced gene expression regulation, plasticity, and survival and how targeting these mechanisms could advance the development of future therapies. In addition, we discuss a recent discovery on how double-strand breaks of genomic DNA mediate the rapid induction of activity-dependent gene expression in neurons.

Cusp Tear of Trifecta™ Aortic Bioprosthesis Resulting in Acute Heart Failure.

Herein is presented the case of an 83-year-old male patient in cardiogenic shock with acute aortic regurgitation that occurred six years after aortic valve replacement (AVR) with a 23 mm Trifecta™ valve. Prosthesis endocarditis was initially suspected because of a floating structure attached to the aortic valve that was visible on echocardiography. Emergency redo-AVR surgery was performed, but no signs of endocarditis were found intraoperatively. Hence, cusp tearing of the implanted bioprosthesis was considered to be the reason for the severe aortic regurgitation.

Microglia-astrocyte crosstalk regulates synapse remodeling via Wnt signaling.

Astrocytes and microglia are emerging key regulators of activity-dependent synapse remodeling that engulf and remove synapses in response to changes in neural activity. Yet, the degree to which these cells communicate to coordinate this process remains an open question. Here, we use whisker removal in postnatal mice to induce activity-dependent synapse removal in the barrel cortex. We show that astrocytes do not engulf synapses in this paradigm. Instead, astrocytes reduce their contact with synapses prior to microglia-mediated synapse engulfment. We further show that reduced astrocyte-contact with synapses is dependent on microglial CX3CL1-CX3CR1 signaling and release of Wnts from microglia following whisker removal. These results demonstrate an activity-dependent mechanism by which microglia instruct astrocyte-synapse interactions, which then provides a permissive environment for microglia to remove synapses. We further show that this mechanism is critical to remodel synapses in a changing sensory environment and this signaling is upregulated in several disease contexts.

HeartMate 3 Snoopy: Noninvasive cardiovascular diagnosis of patients with fully magnetically levitated blood pumps during echocardiographic speed ramp tests and Valsalva maneuvers.

PURPOSE: The HeartMate 3 (HM3) left ventricular assist device (LVAD) has demonstrated excellent clinical outcomes; however, pump speed optimization is challenging with the available HM3 monitoring. Therefore, this study reports on clinical HM3 parameters collected with a noninvasive HM3 monitoring system (HM3 Snoopy) during echocardiographic speed ramp tests and Valsalva maneuvers. METHODS: In this prospective, single-center study, the HM3 data communication between the controller and pump was recorded with a novel data acquisition system. Twelve pump parameters sampled every second (1 Hz) and clinical assessments (echocardiography, electrocardiogram (ECG), and blood pressure measurement) during speed ramp tests were analyzed using Pearson's correlation (r, median [IQR]). The cause for the occurrence of pulsatility index (PI)-events during ramp speed tests and valsalva maneuvers was investigated. RESULTS: In 24 patients (age: 58.9 ± 8.8 years, body mass index: 28.1 ± 5.1 kg/m2, female: 20.8%), 35 speed ramp tests were performed with speed changes in the range of ±1000 rpm from a baseline speed of 5443 ± 244 rpm. Eight HM3 pump parameters from estimated flow, motor current, and LVAD speed together with blood pressure showed positive collinearities (r = 0.9 [0.1]). Negative collinearities were observed for pump flow pulsatility, pulsatility index, rotor noise, and left ventricular diameters (r = -0.8 [0.1]), whereas rotor displacement and heartrate showed absence of collinearities (r = -0.1 [0.08]). CONCLUSIONS: In this study, the HM3 Snoopy was successfully used to acquire more parameters from the HM3 at a higher sampling rate. Analysis of HM3 per-second data provide additional clinical diagnostic information on heart-pump interactions and cause of PI-events.

Neuron Derived Cytokine Interleukin-34 Controls Developmental Microglia Function.

Neuron-microglia interactions dictate the development of neuronal circuits in the brain. However, the factors that support and broadly regulate these processes across developmental stages are largely unknown. Here, we find that IL34, a neuron-derived cytokine, is upregulated in development and plays a critical role in supporting and maintaining neuroprotective, mature microglia in the anterior cingulate cortex (ACC) of mice. We show that IL34 mRNA and protein is upregulated in neurons in the second week of postnatal life and that this increase coincides with increases in microglia number and expression of mature, homeostatic markers, e.g., TMEM119. We also found that IL34 mRNA is higher in more active neurons, and higher in excitatory (compared to inhibitory) neurons. Genetic KO of IL34 prevents the functional maturation of microglia and results in an anxiolytic phenotype in these mice by adulthood. Acute, low dose blocking of IL34 at postnatal day (P)15 in mice decreased microglial TMEM119 expression and increased aberrant microglial phagocytosis of thalamocortical synapses within the ACC. In contrast, viral overexpression of IL34 early in life (P1-P8) caused early maturation of microglia and prevented microglial phagocytosis of thalamocortical synapses during the appropriate neurodevelopmental refinement window. Taken together, these findings establish IL34 as a key regulator of neuron-microglia crosstalk in postnatal brain development, controlling both microglial maturation and synapse engulfment.