Astrocytes mediate cell non-autonomous correction of aberrant firing in human FXS neurons.

Pre-clinical studies of fragile X syndrome (FXS) have focused on neurons, with the role of glia remaining largely underexplored. We examined the astrocytic regulation of aberrant firing of FXS neurons derived from human pluripotent stem cells. Human FXS cortical neurons, co-cultured with human FXS astrocytes, fired frequent short-duration spontaneous bursts of action potentials compared with less frequent, longer-duration bursts of control neurons co-cultured with control astrocytes. Intriguingly, bursts fired by FXS neurons co-cultured with control astrocytes are indistinguishable from control neurons. Conversely, control neurons exhibit aberrant firing in the presence of FXS astrocytes. Thus, the astrocyte genotype determines the neuronal firing phenotype. Strikingly, astrocytic-conditioned medium, and not the physical presence of astrocytes, is capable of determining the firing phenotype. The mechanistic basis of this effect indicates that the astroglial-derived protein, S100ß, restores normal firing by reversing the suppression of a persistent sodium current in FXS neurons.

Return emergency department visits for recurrent pulmonary embolism symptoms in children and adolescents.

Rates of pulmonary embolism (PE) in children have steadily increased over the past 2 decades. Patient outcomes after hospital discharge are poorly understood, and many patients experience recurrent or persistent chest pain or dyspnea, prompting a return to care. This retrospective cohort study of patients diagnosed with PE at a large children's hospital over a 9.5-year period was performed to evaluate rates of return to the emergency department (ED) for PE-related symptoms, and to determine the utility of repeat computed tomography angiography (CTA) in this population. Ninety-six patients were diagnosed with PE during the study period. Forty-two percent of patients (n = 40) returned to the ED for PE-related symptoms and a total of 74 repeat CTAs were performed. Among those who had return visits, the mean number of return visits was 3 and the mean number of repeat CTAs was 1.8. The median time to return to the ED was 34 days. Logistic regression analysis identified increased age and female sex as risk factors for return ED visits. Eight percent of the cohort experienced PE recurrence. Recurrent PE was observed only in those with persistent or new thrombotic risk factors and was uncommon in those who remained on appropriate anticoagulation. Future work should focus on the development of a risk stratification system to identify patients at low risk of recurrence in order to minimize repeat CTA imaging.

Evaluation of venous thromboembolism risk factors reveals subtype heterogenicity in children with central venous catheters: a multicenter study from the Children's Hospital Acquired Thrombosis consortium.

BACKGROUND: Acutely ill and medically complex children frequently rely on central venous catheters (CVCs) to provide life-sustaining treatment. Unfortunately, catheter-related thrombosis (CRT) is a serious and common complication. Little is known why some with a CVC develop CRT and others develop venous thromboembolism unrelated to the CVC (non-CRT). OBJECTIVES: The aim of this study was to identify factors associated with CRT in children with hospital-acquired venous thromboembolism (HA-VTE). METHODS: This case-case study included participants in the Children's Hospital Acquired Thrombosis Registry with HA-VTE and CVC aged 0 to 21 years from 8 US children's hospitals. Participants were excluded if they developed HA-VTE prior to CVC insertion or if the CVC insertion date was unknown. Logistic regression models were used to assess associations between clinical factors and CRT status. RESULTS: There were 1144 participants with HA-VTE who had a CVC. CRT developed in 833 participants, and 311 developed non-CRT. Multivariable analysis showed increased odds of CRT (compared with non-CRT) in participants with peripherally inserted central catheters (odds ratio [OR], 3.80; 95% CI, 2.04-7.10; p < .001), CVCs inserted in the femoral vein (OR, 4.45; 95% CI, 1.70-11.65; p = .002), multiple CVCs (OR, 1.42; 95% CI, 1.18-1.71; p < .001), and CVC malfunction (OR, 3.30; 95% CI, 1.80-6.03; p < .001). CONCLUSION: The findings of this study provide new insights on risk factor differences between CRT and non-CRT. Prevention efforts should be directed at modifying the type of CVC, insertion location, and/or number of CVCs placed, if possible, to decrease the incidence of CRT.

The ciliary gene INPP5E confers dorsal telencephalic identity to human cortical organoids by negatively regulating Sonic hedgehog signaling.

Defects in primary cilia, cellular antennas that control multiple intracellular signaling pathways, underlie several neurodevelopmental disorders, but it remains unknown how cilia control essential steps in human brain formation. Here, we show that cilia are present on the apical surface of radial glial cells in human fetal forebrain. Interfering with cilia signaling in human organoids by mutating the INPP5E gene leads to the formation of ventral telencephalic cell types instead of cortical progenitors and neurons. INPP5E mutant organoids also show increased Sonic hedgehog (SHH) signaling, and cyclopamine treatment partially rescues this ventralization. In addition, ciliary expression of SMO, GLI2, GPR161, and several intraflagellar transport (IFT) proteins is increased. Overall, these findings establish the importance of primary cilia for dorsal and ventral patterning in human corticogenesis, indicate a tissue-specific role of INPP5E as a negative regulator of SHH signaling, and have implications for the emerging roles of cilia in the pathogenesis of neurodevelopmental disorders.

The Histone Deacetylase 9 Stroke-Risk Variant Promotes Apoptosis and Inflammation in a Human iPSC-Derived Smooth Muscle Cells Model.

A common variant in the Histone Deacetylase 9 (HDAC9) gene is the strongest genetic risk for large-vessel stroke, and HDAC9 offers a novel target for therapeutic modulation. However, the mechanisms linking the HDAC9 variant with increased stroke risk is still unclear due to the lack of relevant models to study the underlying molecular mechanisms. We generated vascular smooth muscle cells using human induced pluripotent stem cells with the HDAC9 stroke risk variant to assess HDAC9-mediated phenotypic changes in a relevant cells model and test the efficacy of HDAC inhibitors for potential therapeutic strategies. Our human induced pluripotent stem cells derived vascular smooth muscle cells show enhanced HDAC9 expression and allow us to assess HDAC9-mediated effects on promoting smooth muscle cell dysfunction, including proliferation, migration, apoptosis and response to inflammation. These phenotypes could be reverted by treatment with HDAC inhibitors, including sodium valproate and small molecules inhibitors. By demonstrating the relevance of the model and the efficacy of HDAC inhibitors, our model provides a robust phenotypic screening platform, which could be applied to other stroke-associated genetic variants.

Symptomatic pulmonary embolus after catheter removal in children with catheter related thrombosis: A report from the CHAT Consortium.

BACKGROUND: Appropriate timing of central venous catheter (CVC) removal, in relation to start of anticoagulation, in children after the diagnosis of a CVC-related thrombosis (CRT) is not well established. OBJECTIVES: This retrospective cohort study evaluated the incidence of symptomatic pulmonary embolism (PE) after CVC removal using data from the multi-institutional Children's Hospital-Acquired Thrombosis (CHAT) Consortium Registry. PATIENTS/METHODS: The CHAT Registry consists of data from children aged 0-21 years with a hospital-acquired venous thromboembolism. Eligible subjects were those with CRT diagnosed <3 days after CVC removal. Subjects were excluded if the CRT was due to a failed CVC insertion. Subjects were divided into three groups: those with CVC removal without anticoagulation, those with CVC removal <48 h after starting anticoagulation, and those with CVC removal ≥48 h after starting anticoagulation. RESULTS: A total of 687 CRT events from 663 subjects were included. A majority of CRT events were in subjects with peripherally inserted central catheters (62.3%, n = 428). For the 611 CRT events in which the CVC was removed, there was only one case of symptomatic PE (0.16%), which occurred <48 h after initiation of anticoagulation. CONCLUSIONS: While current guidelines suggest anticoagulation before CVC removal in the setting of a CRT to prevent embolization, CVC removal is not associated with symptomatic PE regardless of duration of anticoagulation before CVC removal.

A New Risk Assessment Model for Hospital-Acquired Venous Thromboembolism in Critically Ill Children: A Report From the Children's Hospital-Acquired Thrombosis Consortium.

OBJECTIVES: To create a risk model for hospital-acquired venous thromboembolism in critically ill children upon admission to an ICU. DESIGN: Case-control study. SETTING: ICUs from eight children's hospitals throughout the United States. SUBJECTS: Critically ill children with hospital-acquired venous thromboembolism (cases) 0-21 years old and similar children without hospital-acquired venous thromboembolism (controls) from January 2012 to December 2016. Children with a recent cardiac surgery, asymptomatic venous thromboembolism, or a venous thromboembolism diagnosed before ICU admission were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The multi-institutional Children's Hospital-Acquired Thrombosis registry was used to identify cases and controls. Multivariable logistic regression was used to determine the association between hospital-acquired venous thromboembolism and putative risk factors present at or within 24 hours of ICU admission to develop the final model. A total of 548 hospital-acquired venous thromboembolism cases (median age, 0.8 yr; interquartile range, 0.1-10.2) and 187 controls (median age, 2.4 yr; interquartile range, 0.2-8.3) were analyzed. In the multivariable model, recent central venous catheter placement (odds ratio, 4.4; 95% CI, 2.7-7.1), immobility (odds ratio 3.6, 95% CI, 2.1-6.2), congenital heart disease (odds ratio 2.9, 95% CI, 1.7-4.7), length of hospital stay prior to ICU admission greater than or equal to 3 days (odds ratio, 2.5; 95% CI, 1.1-5.6), and history of autoimmune/inflammatory condition or current infection (odds ratio, 2.1; 95% CI, 1.2-3.4) were each independently associated with hospital-acquired venous thromboembolism. The risk model had an area under the receiver operating characteristic curve of 0.79 (95% CI, 0.73-0.84). CONCLUSIONS: Using the multicenter Children's Hospital-Acquired Thrombosis registry, we identified five independent risk factors for hospital-acquired venous thromboembolism in critically ill children, deriving a new hospital-acquired venous thromboembolism risk assessment model. A prospective validation study is underway to define a high-risk group for risk-stratified interventional trials investigating the efficacy and safety of prophylactic anticoagulation in critically ill children.

Development of a Risk Model for Pediatric Hospital-Acquired Thrombosis: A Report from the Children's Hospital-Acquired Thrombosis Consortium.

OBJECTIVE: To identify pertinent clinical variables discernible on the day of hospital admission that can be used to assess risk for hospital-acquired venous thromboembolism (HA-VTE) in children. STUDY DESIGN: The Children's Hospital-Acquired Thrombosis Registry is a multi-institutional registry for all hospitalized participants aged 0-21 years diagnosed with a HA-VTE and non-VTE controls. A risk assessment model (RAM) for the development of HA-VTE using demographic and clinical VTE risk factors present at hospital admission was derived using weighted logistic regression and the least absolute shrinkage and selection (Lasso) procedure. The models were internally validated using 5-fold cross-validation. Discrimination and calibration were assessed using area under the receiver operating characteristic curve and Hosmer-Lemeshow goodness of fit, respectively. RESULTS: Clinical data from 728 cases with HA-VTE and 839 non-VTE controls, admitted between January 2012 and December 2016, were abstracted. Statistically significant RAM elements included age <1 year and 10-22 years, cancer, congenital heart disease, other high-risk conditions (inflammatory/autoimmune disease, blood-related disorder, protein-losing state, total parental nutrition dependence, thrombophilia/personal history of VTE), recent hospitalization, immobility, platelet count >350 K/µL, central venous catheter, recent surgery, steroids, and mechanical ventilation. The area under the receiver operating characteristic curve was 0.78 (95% CI 0.76-0.80). CONCLUSIONS: Once externally validated, this RAM will identify those who are at low-risk as well as the greatest-risk groups of hospitalized children for investigation of prophylactic strategies in future clinical trials.

Atypical Outcomes for Hepatitis-associated Acquired Aplastic Anemia: 2 Case Studies and Review of the Literature.

There is little data specifically dedicated to the long-term outcomes of the hepatitis-associated variant of aplastic anemia (HAAA). A majority of patients with nonsevere (moderate) aplastic anemia progress to severe aplastic anemia, and severe aplastic anemia typically results in death if left untreated. We present 2 unique cases of HAAA that contribute to our knowledge of the natural history of this disease variant. One patient had moderate HAAA that never progressed to severe disease. The second patient had severe HAAA that spontaneously resolved without treatment. The rare possibility of moderate HAAA failing to progress to fulfill severe criteria, or of severe HAAA spontaneously improving, may complicate early treatment decisions for some patients.

Generation of twenty four induced pluripotent stem cell lines from twenty four members of the Lothian Birth Cohort 1936.

Cognitive decline is among the most feared aspects of ageing. We have generated induced pluripotent stem cells (iPSCs) from 24 people from the Lothian Birth Cohort 1936, whose cognitive ability was tested in childhood and in older age. Peripheral blood mononuclear cells (PBMCs) were reprogrammed using non-integrating oriP/EBNA1 backbone plasmids expressing six iPSC reprogramming factors (OCT3/4 (POU5F1), SOX2, KLF4, L-Myc, shp53, Lin28, SV40LT). All lines demonstrated STR matched karyotype and pluripotency was validated by multiple methods. These iPSC lines are a valuable resource to study molecular mechanisms underlying individual differences in cognitive ageing and resilience to age-related neurodegenerative diseases.

Conditional Gene Knockout in Human Cells with Inducible CRISPR/Cas9.

The advent of the easily programmable and efficient CRISPR/Cas9 nuclease system has revolutionized genetic engineering. While conventional gene knockout experiments using CRISPR/Cas9 are very valuable, these are not well suited to study stage-specific gene function in dynamic situations such as development or disease. Here we describe a CRISPR/Cas9-based OPTimized inducible gene KnockOut method (OPTiKO) for conditional loss-of-function studies in human cells. This approach relies on an improved tetracycline-inducible system for conditional expression of single guide RNAs (sgRNAs) that drive Cas9 activity. In order to ensure homogeneous and stable expression, the necessary transgenes are expressed following rapid and efficient single-step genetic engineering of the AAVS1 genomic safe harbor. When implemented in human pluripotent stem cells (hPSCs), the approach can be then efficiently applied to virtually any hPSC-derived human cell type at various stages of development or disease.

Improving the Evaluation and Management of Abnormal Uterine Bleeding in Female Adolescents Presenting for Emergency Care.

STUDY OBJECTIVE: We sought to improve emergency care for adolescents with abnormal uterine bleeding (AUB) by developing a clinical effectiveness guideline (CEG) and assessing its effect on quality of care. DESIGN, SETTING, PARTICIPANTS, AND INTERVENTIONS: A stakeholder engagement group designed a CEG algorithm for emergency AUB management. Pediatric residents received CEG training and their knowledge and attitudes were assessed using pre- and post intervention surveys. International Classification of Diseases ninth and 10th revision codes identified electronic health record data for patients who presented to the pediatric emergency department for AUB 6 months before and after CEG implementation. A weighted, 20-point scoring system consisting of prioritized aspects of history, laboratory studies, and management was developed to quantify the quality of care provided. MAIN OUTCOME MEASURES: Descriptive statistics, χ2 test, Wilcoxon rank sum test, and a run chart were used for analysis. RESULTS: Pediatric residents reported higher confidence and knowledge scores post CEG implementation. Of the 91 patients identified, 62 met inclusion criteria. Median score was 14 ± 7 before CEG implementation and 15.5 ± 6 after. The Wilcoxon rank sum test showed a difference in AUB evaluation and management scores (P = .09) after implementation of the CEG. Run chart data showed no shifts or trends (overall median score, 14 points). Pre- and post implementation, points were deducted most frequently for not assessing personal/family clotting disorder history. The largest improvements in care were with appropriate medication dosing and disposition. CONCLUSION: We designed a CEG and educational intervention for AUB management in a pediatric emergency department. These findings suggest our CEG might be an effective tool to improve emergency AUB care for adolescents and could increase trainees' confidence in managing this condition, although additional cycles are needed.

Response to treatment and adverse events associated with use of recombinant activated factor VII in children: a retrospective cohort study.

BACKGROUND: Recombinant activated factor VII (rFVIIa) is United States (US) Food and Drug Administration (FDA)-approved for patients with hemophilia with inhibitors or congenital factor VII deficiency. Initial reports of off-label use highlighted its efficacy, though newer reports have not repeated these findings. In both types of publication, though, secondary thromboses have been seen in adult patients. The data in children are less clear. METHODS: This study analyzed all rFVIIa use at a large children's hospital for characteristics and outcomes. Recipients of rFVIIa were identified retrospectively via the electronic medical record. Data on patient diagnosis, lab data, other treatments, adverse events, and outcomes were collected. RESULTS: Over 33 months, 66 patient episodes were treated with a total of 606 doses (median = 2). The most common indication (36.4%) was gastrointestinal bleeding (24/66 patients). Only one patient received a dose for an approved labeled indication. For control of bleeding, 33.3% of courses were unsuccessful (19/57). Bleeding from multiple sites was associated with treatment failure. In 16.7% of patients (11/66), unexpected adverse thromboses developed within 1 week of completing a course of rFVIIa. Thromboses in both intra- and extra-corporeal sites were included if they compromised patient care. CONCLUSIONS: In the majority of cases reviewed, rFVIIa was successful in stopping or slowing serious bleeding episodes. It was least effective when a patient had diffuse bleeding at the time of administration. The thrombosis rate of 16.7% was higher than expected, though causality cannot be declared. Further investigation is needed to determine the risk-benefit ratio in children.

Venous thromboembolism in pediatric trauma patients: Ten-year experience and long-term follow-up in a tertiary care center.

BACKGROUND: Pediatric trauma patients are at high risk for development of venous thromboembolism (VTE). Our objective is to describe incidence, risk factors, and timing of development of VTE, anticoagulation complications, and long-term VTE outcomes in a critically injured pediatric population. PROCEDURE: We did a retrospective review of pediatric (0-17 years) trauma admissions to intensive care unit from 2005 to 2014. Our center employs VTE screening and prevention protocols for high-risk patients based on hypercoagulable history, age, injuries, and medical interventions. We collected demographics, VTE prevention measures, VTE incidence, therapeutic anticoagulant use, and outcomes including postthrombotic syndrome (PTS) and clot resolution. Analysis included Wilcoxon rank-sum, Fisher exact, and logistic regression modeling. RESULTS: Seven hundred fifty-three subjects were analyzed. No patients on chemical prophylaxis (21/753) developed VTE. Overall incidence of deep vein thrombosis (DVT) was 8.9%; pulmonary embolism (PE) was 0%. Time to diagnosis was median (interquartile range [IQR]) 10.5 (6.5-14.5) days, with 63% of clots being symptomatic. Risk factors for VTE development included severe traumatic brain injury (TBI), acute traumatic coagulopathy (defined by elevated admission international normalized ratio), age less than or equal to 3 or age 13 years or more, injury severity, and child abuse mechanism. At a median (IQR) follow-up of 13 (6-19) months, 52.1% had persistent clot and 15.8% had PTS. Therapeutic anticoagulation was not associated with clot resolution or prevention of PTS. CONCLUSION: TBI therapy is closely linked to the development of DVT. Coagulopathy on admission is associated with hypercoagulability in the postinjury period, suggesting a patient phenotype with systemic coagulation dysregulation. Treatment was not associated with improved VTE outcomes, suggesting that pediatric protocols should emphasize VTE prevention and prophylaxis strategies.

A Comparison of Extremity Thrombosis Rates in Adolescent and Young Adult Versus Younger Pediatric Oncology Patients at a Children's Hospital.

PURPOSE: To examine whether the rates of thrombosis in children (≤14 years of age) and adolescent/young adult (AYA) patients (15-22 years of age) with cancer is different. METHODS: We retrospectively studied the rates of thrombosis in children and AYA patients at the Children's Hospital of Pittsburgh during the years 2002-2010, using the tumor registry database. This list was then divided into two groups based on age at diagnosis. A review of ICD-9 codes from hospital billing records was then performed to identify patients who carried diagnoses of cancer (140.x-239.x) and venous thrombosis of the extremities/vena cavae (453.x) simultaneously. This list was confirmed by electronic medical record review. Proportions, comparisons, and descriptive statistics were then performed. RESULTS: One thousand three hundred nine total patients were identified; 274 patients fit into the AYA age category (mean age 17.3 years) and 1036 patients were in the child group (mean age 6.5 years). Overall, 30 patients (2.29%) had thrombosis: 4.76% of the AYA patients (13/273) and 1.64% of the child group (17/1036). The difference in these proportions had a p-value = 0.004. CONCLUSIONS: This study suggests that the risk of extremity deep vein thrombosis is higher in the AYA subset of oncology patients than in the patients who are 14 years or younger. Prospective studies to elucidate the true rate of thrombosis, as well as to study the benefit of prophylactic anticoagulation in the AYA population, should be undertaken.

Optimized inducible shRNA and CRISPR/Cas9 platforms for in vitro studies of human development using hPSCs.

Inducible loss of gene function experiments are necessary to uncover mechanisms underlying development, physiology and disease. However, current methods are complex, lack robustness and do not work in multiple cell types. Here we address these limitations by developing single-step optimized inducible gene knockdown or knockout (sOPTiKD or sOPTiKO) platforms. These are based on genetic engineering of human genomic safe harbors combined with an improved tetracycline-inducible system and CRISPR/Cas9 technology. We exemplify the efficacy of these methods in human pluripotent stem cells (hPSCs), and show that generation of sOPTiKD/KO hPSCs is simple, rapid and allows tightly controlled individual or multiplexed gene knockdown or knockout in hPSCs and in a wide variety of differentiated cells. Finally, we illustrate the general applicability of this approach by investigating the function of transcription factors (OCT4 and T), cell cycle regulators (cyclin D family members) and epigenetic modifiers (DPY30). Overall, sOPTiKD and sOPTiKO provide a unique opportunity for functional analyses in multiple cell types relevant for the study of human development.