Mechanisms Underlying Circuit Dysfunction in Neurodevelopmental Disorders.

Recent advances in genomics have revealed a wide spectrum of genetic variants associated with neurodevelopmental disorders at an unprecedented scale. An increasing number of studies have consistently identified mutations-both inherited and de novo-impacting the function of specific brain circuits. This suggests that, during brain development, alterations in distinct neural circuits, cell types, or broad regulatory pathways ultimately shaping synapses might be a dysfunctional process underlying these disorders. Here, we review findings from human studies and animal model research to provide a comprehensive description of synaptic and circuit mechanisms implicated in neurodevelopmental disorders. We discuss how specific synaptic connections might be commonly disrupted in different disorders and the alterations in cognition and behaviors emerging from imbalances in neuronal circuits. Moreover, we review new approaches that have been shown to restore or mitigate dysfunctional processes during specific critical windows of brain development. Considering the heterogeneity of neurodevelopmental disorders, we also highlight the recent progress in developing improved clinical biomarkers and strategies that will help to identify novel therapeutic compounds and opportunities for early intervention.

The Upstream Sequence Transcription Complex dictates nucleosome positioning and promoter accessibility at piRNA genes in the C. elegans germ line.

The piRNA pathway is a conserved germline-specific small RNA pathway that ensures genomic integrity and continued fertility. In C. elegans and other nematodes, Type-I piRNAs are expressed from >10,000 independently transcribed genes clustered within two discrete domains of 1.5 and 3.5 MB on Chromosome IV. Clustering of piRNA genes contributes to their germline-specific expression, but the underlying mechanisms are unclear. We analyze isolated germ nuclei to demonstrate that the piRNA genomic domains are located in a heterochromatin-like environment. USTC (Upstream Sequence Transcription Complex) promotes strong association of nucleosomes throughout piRNA clusters, yet organizes the local nucleosome environment to direct the exposure of individual piRNA genes. Localization of USTC to the piRNA domains depends upon the ATPase chromatin remodeler ISW-1, which maintains high nucleosome density across piRNA clusters and ongoing production of piRNA precursors. Overall, this work provides insight into how chromatin states coordinate transcriptional regulation over large genomic domains, with implications for global genome organization.

TMEM161B regulates cerebral cortical gyration, Sonic Hedgehog signaling, and ciliary structure in the developing central nervous system.

Sonic hedgehog signaling regulates processes of embryonic development across multiple tissues, yet factors regulating context-specific Shh signaling remain poorly understood. Exome sequencing of families with polymicrogyria (disordered cortical folding) revealed multiple individuals with biallelic deleterious variants in TMEM161B, which encodes a multi-pass transmembrane protein of unknown function. Tmem161b null mice demonstrated holoprosencephaly, craniofacial midline defects, eye defects, and spinal cord patterning changes consistent with impaired Shh signaling, but were without limb defects, suggesting a CNS-specific role of Tmem161b. Tmem161b depletion impaired the response to Smoothened activation in vitro and disrupted cortical histogenesis in vivo in both mouse and ferret models, including leading to abnormal gyration in the ferret model. Tmem161b localizes non-exclusively to the primary cilium, and scanning electron microscopy revealed shortened, dysmorphic, and ballooned ventricular zone cilia in the Tmem161b null mouse, suggesting that the Shh-related phenotypes may reflect ciliary dysfunction. Our data identify TMEM161B as a regulator of cerebral cortical gyration, as involved in primary ciliary structure, as a regulator of Shh signaling, and further implicate Shh signaling in human gyral development.

Modeling oxygen transport in the brain: An efficient coarse-grid approach to capture perivascular gradients in the parenchyma.

Recent progresses in intravital imaging have enabled highly-resolved measurements of periarteriolar oxygen gradients (POGs) within the brain parenchyma. POGs are increasingly used as proxies to estimate the local baseline oxygen consumption, which is a hallmark of cell activity. However, the oxygen profile around a given arteriole arises from an interplay between oxygen consumption and delivery, not only by this arteriole but also by distant capillaries. Integrating such interactions across scales while accounting for the complex architecture of the microvascular network remains a challenge from a modelling perspective. This limits our ability to interpret the experimental oxygen maps and constitutes a key bottleneck toward the inverse determination of metabolic rates of oxygen. We revisit the problem of parenchymal oxygen transport and metabolism and introduce a simple, conservative, accurate and scalable direct numerical method going beyond canonical Krogh-type models and their associated geometrical simplifications. We focus on a two-dimensional formulation, and introduce the concepts needed to combine an operator-splitting and a Green's function approach. Oxygen concentration is decomposed into a slowly-varying contribution, discretized by Finite Volumes over a coarse cartesian grid, and a rapidly-varying contribution, approximated analytically in grid-cells surrounding each vessel. Starting with simple test cases, we thoroughly analyze the resulting errors by comparison with highly-resolved simulations of the original transport problem, showing considerable improvement of the computational-cost/accuracy balance compared to previous work. We then demonstrate the model ability to flexibly generate synthetic data reproducing the spatial dynamics of oxygen in the brain parenchyma, with sub-grid resolution. Based on these synthetic data, we show that capillaries distant from the arteriole cannot be overlooked when interpreting POGs, thus reconciling recent measurements of POGs across cortical layers with the fundamental idea that variations of vascular density within the depth of the cortex may reveal underlying differences in neuronal organization and metabolic load.

Input-specific control of interneuron numbers in nascent striatal networks.

The assembly of functional neuronal circuits requires appropriate numbers of distinct classes of neurons, but the mechanisms through which their relative proportions are established remain poorly defined. Investigating the mouse striatum, we found that the two most prominent subtypes of striatal interneurons, parvalbumin-expressing (PV+) GABAergic and cholinergic (ChAT+) interneurons, undergo extensive programmed cell death between the first and second postnatal weeks. Remarkably, the survival of PV+ and ChAT+ interneurons is regulated by distinct mechanisms mediated by their specific afferent connectivity. While long-range cortical inputs control PV+ interneuron survival, ChAT+ interneuron survival is regulated by local input from the medium spiny neurons. Our results identify input-specific circuit mechanisms that operate during the period of programmed cell death to establish the final number of interneurons in nascent striatal networks.

Analysis of >3400 worldwide eggplant accessions reveals two independent domestication events and multiple migration-diversification routes.

Eggplant (Solanum melongena) is an important Solanaceous crop, widely cultivated and consumed in Asia, the Mediterranean basin, and Southeast Europe. Its domestication centers and migration and diversification routes are still a matter of debate. We report the largest georeferenced and genotyped collection to this date for eggplant and its wild relatives, consisting of 3499 accessions from seven worldwide genebanks, originating from 105 countries in five continents. The combination of genotypic and passport data points to the existence of at least two main centers of domestication, in Southeast Asia and the Indian subcontinent, with limited genetic exchange between them. The wild and weedy eggplant ancestor S. insanum shows admixture with domesticated S. melongena, similar to what was described for other fruit-bearing Solanaceous crops such as tomato and pepper and their wild ancestors. After domestication, migration and admixture of eggplant populations from different regions have been less conspicuous with respect to tomato and pepper, thus better preserving 'local' phenotypic characteristics. The data allowed the identification of misclassified and putatively duplicated accessions, facilitating genebank management. All the genetic, phenotypic, and passport data have been deposited in the Open Access G2P-SOL database, and constitute an invaluable resource for understanding the domestication, migration and diversification of this cosmopolitan vegetable.

Colonization-persistence trade-offs in natural bacterial communities.

Fitness equalizing mechanisms, such as trade-offs, are recognized as one of the main factors promoting species coexistence in community ecology. However, they have rarely been explored in microbial communities. Although microbial communities are highly diverse, the coexistence of their multiple taxa is largely attributed to niche differences and high dispersal rates, following the principle 'everything is everywhere, but the environment selects'. We use a dynamical stochastic model based on the theory of island biogeography to study highly diverse bacterial communities over time across three different systems (soils, alpine lakes and shallow saline lakes). Assuming fitness equalization mechanisms, here we newly analytically derive colonization-persistence trade-offs, and report a signal of such trade-offs in natural bacterial communities. Moreover, we show that different subsets of species in the community drive this trade-off. Rare taxa, which are occasional and more likely to follow independent colonization/extinction dynamics, drive this trade-off in the aquatic communities, while the core sub-community did it in the soils. We conclude that equalizing mechanisms may be more important than previously recognized in bacterial communities. Our work also emphasizes the fundamental value of dynamical models for understanding temporal patterns and processes in highly diverse communities.

Clinical impact of time to results from the microbiology laboratory in bloodstream infections caused by carbapenemase-producing Enterobacterales (TIME-CPE STUDY).

OBJECTIVES: To evaluate the impact of time to results (TTR) on the outcome of patients with carbapenemase-producing Enterobacterales bloodstream infections (CPE-BSI). METHODS: Times-series study conducted from January 2014 to December 2021, selecting patients with first CPE-BSI episodes. Periods of intervention were defined according to implementation of diagnostic bundle tests in the microbiology laboratory: pre-intervention (January 2014-December 2017) and post-intervention (January 2018-December 2021). TTR was defined as time elapsed from positivity time of the blood culture bottles to physicians' notification of CPE-BSI episodes, and was evaluated in patients who received inappropriate empirical and switched to appropriate targeted treatment (switch group). Analysis of a composite unfavourable outcome (mortality at Day 30 and/or persistent and/or recurrent bacteraemia) was performed for the total episodes and in the switch group. RESULTS: One hundred and nine episodes were analysed: 66 pre-intervention and 43 post-intervention. Compared with pre-intervention, patients in the post-intervention period were younger (68 versus 63 years, P = 0.04), had INCREMENT score > 7 (31.8% versus 53.5%, P = 0.02) and unfavourable outcome (37.9% versus 20.9%, P = 0.04). Proportion of TTR > 30 h was more frequent pre-intervention than post-intervention (61.7% versus 35.5%, P = 0.02). In multivariate analysis of the 109 episodes, source other than urinary or biliary (OR 2.76, 95% CI 1.11-6.86) was associated with unfavourable outcome, while targeted appropriate treatment trended to being protective (OR 0.17, 95% CI 0.03-1.00). Considering the switch group (n = 78), source other than urinary or biliary (OR 14.9, 95% CI 3.25-69.05) and TTR > 30 h (OR 4.72, 95% CI 1.29-17.22) were associated with unfavourable outcome. CONCLUSIONS: Decreased TTR in the post-intervention period was associated with the outcome in patients with CPE-BSI episodes.

Understanding stochastic and deterministic assembly processes in microbial communities along temporal, spatial and environmental scales.

Identifying the main drivers of community assembly remains an open fundamental question in ecology. Dispersal processes introduce randomness in community composition while selection for particular environments creates predictable assemblages. However, the interaction between selection and dispersal processes is still poorly understood. Here, we address this question in bacterial and microeukaryotic communities inhabiting a highly dynamic system of ephemeral (hyper)saline lakes. We show that the combination of beta-diversity decomposition methods and a temporal approach based on colonization and extinction dynamics yields new insights into the relative effect of selection and dispersal along environmental gradients. Selective pressure and dispersal-related processes simultaneously shape each local community with variable strength and effect. The dominance of selection vs. dispersal shifted from stochastic to deterministic assembly as salinity increased along the gradient. This transition also had an impact on the temporal dynamics of the lakes as community turnover decreased at high salinities because both colonization and extinction rates slowed down. Only microeukaryotic richness decreased along the gradient due to lower effective colonization at higher salinities, suggesting that the net effect of selection and dispersal is determined by both environmental conditions and the idiosyncrasy of the different microbial ecologies. Our results emphasize the use of temporal approaches in combination with standard statistical methods for a better understanding of the dynamic processes underlying community assembly.

Conventional and new genetic resources for an eggplant breeding revolution.

Eggplant (Solanum melongena) is a major vegetable crop with great potential for genetic improvement owing to its large and mostly untapped genetic diversity. It is closely related to over 500 species of Solanum subgenus Leptostemonum that belong to its primary, secondary, and tertiary genepools and exhibit a wide range of characteristics useful for eggplant breeding, including traits adaptive to climate change. Germplasm banks worldwide hold more than 19 000 accessions of eggplant and related species, most of which have yet to be evaluated. Nonetheless, eggplant breeding using the cultivated S. melongena genepool has yielded significantly improved varieties. To overcome current breeding challenges and for adaptation to climate change, a qualitative leap forward in eggplant breeding is necessary. The initial findings from introgression breeding in eggplant indicate that unleashing the diversity present in its relatives can greatly contribute to eggplant breeding. The recent creation of new genetic resources such as mutant libraries, core collections, recombinant inbred lines, and sets of introgression lines will be another crucial element and will require the support of new genomics tools and biotechnological developments. The systematic utilization of eggplant genetic resources supported by international initiatives will be critical for a much-needed eggplant breeding revolution to address the challenges posed by climate change.

Severe community-acquired Streptococcus pneumoniae bacterial meningitis: clinical and prognostic picture from the intensive care unit.

BACKGROUND: Severe community-acquired pneumococcal meningitis is a medical emergency. The aim of the present investigation was to evaluate the epidemiology, management and outcomes of this condition. METHODS: This was a retrospective, observational and multicenter cohort study. Sixteen Spanish intensive care units (ICUs) were included. Demographic, clinical and microbiological variables from patients with Streptococcus pneumoniae meningitis admitted to ICU were evaluated. Clinical response was evaluated at 72 h after antibiotic treatment initiation, and meningitis complications, length of stay and 30-day mortality were also recorded. RESULTS: In total, 255 patients were included. Cerebrospinal fluid (CSF) culture was positive in 89.7%; 25.7% were non-susceptible to penicillin, and 5.2% were non-susceptible to ceftriaxone or cefotaxime. The most frequent empiric antibiotic regimen was third-generation cephalosporin (47.5%) plus vancomycin (27.8%) or linezolid (12.9%). A steroid treatment regimen was administered to 88.6% of the patients. Clinical response was achieved in 65.8% of patients after 72 h of antibiotic treatment. Multivariate analysis identified two factors associated with early treatment failure: invasive mechanical ventilation (OR 10.74; 95% CI 3.04-37.95, p < 0.001) and septic shock (OR 1.18; 95% CI 1.03-1.36, p = 0.017). The 30-day mortality rate was 13.7%. Only three factors were independently associated with 30-day mortality: delay in start of antibiotic treatment (OR 18.69; 95% CI 2.13-163.97, p = 0.008), Sepsis-related Organ Failure Assessment (SOFA) score (OR 1.36; 95% CI 1.12-1.66, p = 0.002) and early treatment failure (OR 21.75 (3.40-139.18), p = 0.001). Neurological complications appeared in 124 patients (48.63%). CONCLUSIONS: Mortality rate in critically ill patients with pneumococcal meningitis is lower than previously reported. Delay in antibiotic treatment following admission is the only amendable factor associated with mortality.

Treatments for multi-system inflammatory syndrome in children - discharge, fever, and second-line therapies.

Scarce evidence exists about the best treatment for multi-system inflammatory syndrome (MIS-C). We analyzed the effects of steroids, intravenous immunoglobulin (IVIG), and their combination on the probability of discharge over time, the probability of switching to second-line treatment over time, and the persistence of fever 2 days after treatment. We did a retrospective study to investigate the effect of different treatments on children with MIS-C from 1 March 2020 to 1 June 2021. We estimated the time-to-event probability using a Cox model weighted by propensity score to balance the baseline characteristics. Thirty of 132 (22.7%) patients were initially treated with steroids alone, 29/132 (21.9%) with IVIG alone, and 73/132 (55%) with IVIG plus steroids. The probability of early discharge was higher with IVIG than with IVIG plus steroids (hazard ratio [HR] 1.65, 95% CI 1.11-2.45, p = 0.013), but with a higher probability of needing second-line therapy compared to IVIG plus steroids (HR 3.05, 95% CI 1.12-8.25, p = 0.028). Patients on IVIG had a higher likelihood of persistent fever than patients on steroids (odds ratio [OR] 4.23, 95% CI 1.43-13.5, p = 0.011) or on IVIG plus steroids (OR 4.4, 95% CI 2.05-9.82, p < 0.001). No differences were found for this endpoint between steroids or steroids plus IVIG.    Conclusions: The benefits of each approach may vary depending on the outcome assessed. IVIG seemed to increase the probability of earlier discharge over time but also of needing second-line treatment over time. Steroids seemed to reduce persistent fever, and combination therapy reduced the need for escalating treatment. What is Known: • Steroids plus intravenous immunoglobulin, compared with intravenous immunoglobulin alone for multi-system inflammatory syndrome (MIS-C) might reduce the need for hemodynamic support and the duration of fever, but the certainty of the evidence is low. What is New: • Intravenous immunoglobulin, steroids, and their combination for MIS-C may have different outcomes. • In this study, intravenous immunoglobulin increased the probability of discharge over time, steroids reduced persistent fever, while combination therapy reduced the need for second-line treatments.

Epidemiology and clinical features of Streptococcus pyogenes bloodstream infections in children in Madrid, Spain.

Studies have shown increased invasive Group A Streptococcus (GAS) disease, including bloodstream infections (GAS-BSI). However, the epidemiological data of GAS-BSI are limited in children. We aimed to describe GAS-BSI in children in Madrid, over 13 years (2005-2017). Multicenter retrospective cohort study from 16 hospitals from Madrid, Spain. Epidemiology, symptomatology, laboratory, treatment, and outcome of GAS-BSI in children ≤ 16 years were analyzed. 109 cases of GAS-BSI were included, with incidence rate of 4.3 episodes/100,000 children attended at the emergency department/year. We compared incidence between two periods (P1: 2005-June 2011 vs P2: July 2011-2017) and observed a non-significant increase along the study period (annual percentage change: + 6.0% [95%CI: -2.7, + 15.4]; p = 0.163). Median age was 24.1 months (IQR: 14.0-53.7), peaking during the first four years of life (89/109 cases; 81.6%). Primary BSI (46.8%), skin and soft tissue (21.1%), and osteoarticular infections (18.3%) were the most common syndromes. We compared children with primary BSI with those with a known source and observed that the former had shorter hospital stay (7 vs. 13 days; p = 0.003) and received intravenous antibiotics less frequently (72.5% vs. 94.8%; p = 0.001) and for shorter duration of total antibiotic therapy (10 vs. 21 days; p = 0.001). 22% of cases required PICU admission. Factors associated with severity were respiratory distress, pneumonia, thrombocytopenia, and surgery, but in multivariate analysis, only respiratory distress remained significant (adjusted OR:9.23 [95%CI: 2.16-29.41]). Two children (1.8%) died.   Conclusion: We observed an increasing, although non-significant, trend of GAS-BSI incidence within the study. Younger children were more frequently involved, and primary BSI was the most common and less severe syndrome. PICU admission was frequent, being respiratory distress the main risk factor. What is known: • In recent decades, several reports have shown a worldwide increase in the incidence of invasive Group A streptococcal disease (GAS), including bloodstream infection (BSI). Recently, there have been a few reports showing an increase in severity as well. • There needs to be more information on the epidemiology in children since most studies predominantly include adults. What is new: • This study, carried out in children with GAS-BSI in Madrid, shows that GAS-BSI affects mostly younger children, with a broad spectrum of manifestations, needing PICU admission frequently. Respiratory distress was the leading risk factor for severity, whereas primary BSI seemed to be less severe. • We observed an increasing, although non-significant, trend of GAS-BSI incidence in recent years (2005-2017).

Acute Epstein-Barr virus infection: Diagnostic challenge in young children, risk factors for hospitalisation and cytomegalovirus co-detection.

AIM: Acute Epstein-Barr virus (aEBV) and cytomegalovirus (CMV) infections frequently have similar manifestations. We aim to evaluate the characteristics of aEBV infection, risk factors for hospitalisation and differences according to CMV IgM detection (EBV-CMV co-detection) in children. METHODS: Retrospective, single-centre study including patients <16 years diagnosed with aEBV infection (positive anti-EBV IgM/Paul-Bunnell test and acute symptomatology). EBV-CMV co-detection was defined as positive CMV IgM. Factors associated with age, hospitalisation and EBV-CMV co-detection were analysed in a multivariate analysis. RESULTS: A total of 149 patients were included (median age 4.6 years). Most frequent manifestations were fever (77%), cervical lymphadenopathy (64%) and elevated liver enzymes (54%). Younger children had lower rate of positive Paul-Bunnell test (35% vs. 87%; p < 0.01), but higher rate of EBV-CMV co-detection (54% vs. 29%; p = 0.03). These children tended to have less typical symptoms of infectious mononucleosis and higher hospitalisation rate. The overall antibiotic prescription was 49%. Hospitalisation (27 children; 18%) was independently associated with prior antibiotic therapy and anaemia. Sixty-two cases (42%) had EBV-CMV co-detection, which was independently associated with elevated liver enzymes and younger age. CONCLUSION: In this study, younger children with aEBV infection presented more frequently with atypical clinical symptoms, had higher EBV-CMV co-detection rates and were more often hospitalised. Hospitalisation was associated with prior antibiotic prescription.

NRF2 loss recapitulates heritable impacts of paternal cigarette smoke exposure.

Paternal cigarette smoke (CS) exposure is associated with increased risk of behavioral disorders and cancer in offspring, but the mechanism has not been identified. Here we use mouse models to investigate mechanisms and impacts of paternal CS exposure. We demonstrate that CS exposure induces sperm DNAme changes that are partially corrected within 28 days of removal from CS exposure. Additionally, paternal smoking is associated with changes in prefrontal cortex DNAme and gene expression patterns in offspring. Remarkably, the epigenetic and transcriptional effects of CS exposure that we observed in wild type mice are partially recapitulated in Nrf2-/- mice and their offspring, independent of smoking status. Nrf2 is a central regulator of antioxidant gene transcription, and mice lacking Nrf2 consequently display elevated oxidative stress, suggesting that oxidative stress may underlie CS-induced heritable epigenetic changes. Importantly, paternal sperm DNAme changes do not overlap with DNAme changes measured in offspring prefrontal cortex, indicating that the observed DNAme changes in sperm are not directly inherited. Additionally, the changes in sperm DNAme associated with CS exposure were not observed in sperm of unexposed offspring, suggesting the effects are likely not maintained across multiple generations.

Accuracy of Xpert Ultra for the diagnosis of paediatric tuberculosis in a low TB burden country: a prospective multicentre study.

INTRODUCTION: Childhood pulmonary tuberculosis (TB) remains a diagnostic challenge. This study aimed to evaluate the performance of Xpert Ultra for the diagnosis of pulmonary TB in children in a low TB prevalence setting. METHODS: Prospective, multicentre, diagnostic accuracy study. Children with clinical or radiological suspicion of pulmonary TB were recruited at 11 paediatric units in Spain. Up to three gastric or sputum specimens were taken on 3 consecutive days, and analysed by Xpert MTB/RIF, Xpert Ultra and culture in parallel. RESULTS: 86 children were included (median age 4.9 years, IQR 2.0-10.0; 51.2% male). The final diagnosis was pulmonary TB in 75 patients (87.2%); 33 (44.0%) were microbiologically confirmed. A total of 219 specimens, comprising gastric aspirates (n=194; 88.6%) and sputum specimens (n=25; 11.4%), were analysed. Using culture as reference standard and comparing individual specimens, the sensitivity was 37.8% (14/37) for Xpert MTB/RIF and 81.1% (30/37) for Xpert Ultra (p<0.001); specificity was 98.4% (179/182) and 93.4% (170/182), respectively (p=0.02). In the per-patient analysis, considering positive results on any specimen, the sensitivity was 42.9% (9/21) for Xpert MTB/RIF and 81.0% for Xpert Ultra (17/21, p=0.01); specificity was 96.9% (63/65) and 87.7% (57/65, p=0.07), respectively. CONCLUSIONS: In children with pulmonary TB in a low burden setting, Xpert Ultra has significantly higher sensitivity than the previous generation of Xpert assay and only marginally lower specificity. Therefore, in children undergoing evaluation for suspected pulmonary TB, Xpert Ultra should be used in preference to Xpert MTB/RIF whenever possible.

High-throughput micropatterning platform reveals Nodal-dependent bisection of peri-gastrulation-associated versus preneurulation-associated fate patterning.

In vitro models of postimplantation human development are valuable to the fields of regenerative medicine and developmental biology. Here, we report characterization of a robust in vitro platform that enabled high-content screening of multiple human pluripotent stem cell (hPSC) lines for their ability to undergo peri-gastrulation-like fate patterning upon bone morphogenetic protein 4 (BMP4) treatment of geometrically confined colonies and observed significant heterogeneity in their differentiation propensities along a gastrulation associable and neuralization associable axis. This cell line-associated heterogeneity was found to be attributable to endogenous Nodal expression, with up-regulation of Nodal correlated with expression of a gastrulation-associated gene profile, and Nodal down-regulation correlated with a preneurulation-associated gene profile expression. We harness this knowledge to establish a platform of preneurulation-like fate patterning in geometrically confined hPSC colonies in which fates arise because of a BMPs signalling gradient conveying positional information. Our work identifies a Nodal signalling-dependent switch in peri-gastrulation versus preneurulation-associated fate patterning in hPSC cells, provides a technology to robustly assay hPSC differentiation outcomes, and suggests conserved mechanisms of organized fate specification in differentiating epiblast and ectodermal tissues.

Risk-score based strategy to minimize antibiotic exposure in children with sickle cell disease and fever.

Severe bacterial infections (SBI) have become less frequent in children with sickle cell disease (SCD) in the last decades. However, because of their potential risk of SBI, they usually receive empirical therapy with broad-spectrum antibiotics when they develop fever and are hospitalized in many cases. We performed a prospective study including 79 SCD patients with fever [median age 4.1 (1.7-7.5) years, 78.5% males; 17 of the episodes were diagnosed with SBI and 4 of them were confirmed] and developed a risk score for the prediction of SBI. The optimal score included CRP > 3 mg/dl, IL-6 > 125 pg/ml and hypoxemia, with an AUC of 0.91 (0.83-0.96) for the prediction of confirmed SBI and 0.86 (0.77-0.93) for possible SBI. We classified the patients in 3 groups: low, intermediate and high risk of SBI. Our risk-score-based management proposal could help to safely minimize antibiotic treatments and hospital admissions in children with SCD at low risk of SBI.

Prevalence of M184V and K65R in proviral DNA from PBMCs in HIV-infected youths with lamivudine/emtricitabine exposure.

OBJECTIVES: We analysed the prevalence of M184V/I and/or K65R/E/N mutations archived in proviral DNA (pDNA) in youths with perinatal HIV, virological control and who previously carried these resistance mutations in historic plasma samples. METHODS: We included vertically HIV-infected youths/young adults aged ≥10 years in the Madrid Cohort of HIV-1 Infected Children and Adolescents, exposed to lamivudine and/or emtricitabine, with M184V/I and/or K65R/E/N in historic plasma samples, on antiretroviral therapy (ART), virologically suppressed (HIV-1 RNA <50 copies/mL), and with available PBMCs in the Spanish HIV BioBank. Genomic DNA was extracted from PBMCs and HIV-1 RT gene was amplified and sequenced for resistance testing by Stanford HIV Resistance tool. RESULTS: Among the 225 patients under follow-up in the study cohort, 13 (5.8%) met selection criteria, and RT sequences were recovered in 12 (92.3%) of them. All but one were Spaniards, carrying subtype B, with a median age at PBMCs sampling of 21.3 years (IQR: 15.6-23.1) with 4 years (IQR 2.1-6.5) of suppressed viral load (VL). Nine (75%) youths did not present M184V/I in pDNA after at least 1 year of viral suppression. In December 2019, the remaining three subjects carrying M184V/I in pDNA maintained suppressed viraemia, and two still used emtricitabine in ART. CONCLUSIONS: The prevalence of resistance mutations to lamivudine and emtricitabine in pDNA in a cohort of youths perinatally infected with HIV who remain with undetectable VL, previously lamivudine and/or emtricitabine experienced, was infrequent. Our results indicate that ART including lamivudine or emtricitabine may also be safe and successful in youths with perinatal HIV with previous experience of and resistances to these drugs detected in plasma.

Interleukin 6 as a marker of severe bacterial infection in children with sickle cell disease and fever: a case-control study.

BACKGROUND: Etiological diagnosis of fever in children with sickle cell disease (SCD) is often challenging. The aim of this study was to analyze the pattern of inflammatory biomarkers in SCD febrile children and controls, in order to determine predictors of severe bacterial infection (SBI). METHODS: A prospective, case-control study was carried out during 3 years, including patients younger than 18 years with SCD and fever (cases) and asymptomatic steady-state SCD children (controls). Clinical characteristics and laboratory parameters, including 10 serum proinflammatory cytokines (IL-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-17a, IFN-γ and TNF-α) and comparisons among study subgroups were analyzed. RESULTS: A total of 137 patients (79 cases and 58 controls) were included in the study; 78.5% males, median age 4.1 (1.7-7.5) years. Four cases were diagnosed with SBI, 41 viral infection (VI), 33 no proven infection (NPI) and 1 bacterial-viral coinfection (the latter excluded from the subanalyses). IL-6 was significantly higher in patients with SBI than in patients with VI or NPI (163 vs 0.7 vs 0.7 pg/ml, p < 0.001), and undetectable in all controls. The rest of the cytokines analyzed did not show any significant difference. The optimal cut-off value of IL-6 for the diagnosis of SBI was 125 pg/mL, with high PPV and NPV (PPV of 100% for a prevalence rate of 5, 10 and 15% and NPV of 98.7%, 97.3% and 95.8% for those prevalences rates, respectively). CONCLUSION: We found that IL-6 (with a cut-off value of 125 pg/ml) was an optimal marker for SBI in this cohort of febrile SCD children, with high PPV and NPV. Therefore, given its rapid elevation, IL-6 may be useful to early discriminate SCD children at risk of SBI, in order to guide their management.