Leukocyte telomere length in paediatric critical illness

__Background:__ Children who have suffered from critical illnesses that required treatment in a paediatric intensive care unit (PICU) have long-term physical and neurodevelopmental impairments. The mechanisms underlying this legacy remain largely unknown. In patients suffering from chronic diseases hallmarked by inflammation and oxidative stress, poor long-term outcome has been associated with shorter telomeres. Shortened telomeres have also been reported to result from excessive food consumption and/or unhealthy nutrition. We investigated whether critically ill children admitted to the PICU have shorter-than-normal telomeres, and whether early parenteral nutrition (PN) independently affects telomere length when adjusting for known determinants of telomere length. __Methods:__ Telomere length was quantified in leukocyte DNA from 342 healthy children and from 1148 patients who had been enrolled in the multicenter, randomised controlled trial (RCT), PEPaNIC. These patients were randomly allocated to initiation of PN within 24 h (early PN) or to withholding PN for one week in PICU (late PN). The impact of early PN versus late PN on the change in telomere length from the first to last PICU-day was investigated with multivariable linear regression analyses. __Results:__ Leukocyte telomeres were 6% shorter than normal upon PICU admission (median 1.625 (IQR 1.446-1.825) telomere/single-copy-gene ratio (T/S) units vs. 1.727 (1.547-1.915) T/S-units in healthy children (P < 0.0001)). Adjusted for potential baseline determinants and leukocyte composition, early PN was associated with telomere shortening during PICU stay as compared with late PN (estimate early versus late PN -0.021 T/S-units, 95% CI -0.038; 0.004, P = 0.01). Other independent determinants of telomere length identified in this model were age, gender, baseline telomere length and fraction of neutrophils in the sample from which the DNA was extracted. Telomere shortening with early PN was independent of post-randomisation factors affected by early PN, including longer length of PICU stay, larger amounts of insulin and higher risk of infection. __Conclusions:__ Shorter than normal leukocyte telomeres are present in critically ill children admitted to the PICU. Early initiation of PN further shortened telomeres, an effect that was independent of other determinants. Whether such telomere-shortening predisposes to long-term consequences of paediatric critical illness should be further investigated in a prospective follow-up study

Identification of a Functional Non-coding Variant in the GABAA Receptor α2 Subunit of the C57BL/6J Mouse Reference Genome: Major Implications for Neuroscience Research

GABA type-A (GABA-A) receptors containing the α2 subunit (GABRA2) are expressed in most brain regions and are critical in modulating inhibitory synaptic function. Genetic variation at the GABRA2 locus has been implicated in epilepsy, affective and psychiatric disorders, alcoholism and drug abuse. Gabra2 expression varies as a function of genotype and is modulated by sequence variants in several brain structures and populations, including F2 crosses originating from C57BL/6J (B6J) and the BXD recombinant inbred family derived from B6J and DBA/2J. Here we demonstrate a global reduction of GABRA2 brain protein and mRNA in the B6J strain relative to other inbred strains, and identify and validate the causal mutation in B6J. The mutation is a single base pair deletion located in an intron adjacent to a splice acceptor site that only occurs in the B6J reference genome. The deletion became fixed in B6J between 1976 and 1991 and is now pervasive in many engineered lines, BXD strains generated after 1991, the Collaborative Cross, and the majority of consomic lines. Repair of the deletion using CRISPR-Cas9-mediated gene editing on a B6J genetic background completely restored brain levels of GABRA2 protein and mRNA. Comparison of transcript expression in hippocampus, cortex, and striatum between B6J and repaired genotypes revealed alterations in GABA-A receptor subunit expression, especially in striatum. These results suggest that naturally occurring variation in GABRA2 levels between B6J and other substrains or inbred strains may also explain strain differences in anxiety-like or alcohol and drug response traits related to striatal function. Characterization of the B6J private mutation in the Gabra2 gene is of critical importance to molecular genetic studies in neurobiological research because this strain is widely used to generate genetically engineered mice and murine genetic populations, and is the most widely utilized strain for evaluation of anxiety-like, depression-like, pain, epilepsy, and drug response traits that may be partly modulated by GABRA2 function

Effect of intravenous 25OHD supplementation on bone turnover and inflammation in prolonged critically ill patients: a pilot study

Critically ill patients have low circulating 25-hydroxyvitamin D (25OHD), vitamin D binding protein (DBP), and 1,25-dihydroxyvitamin D [1,25(OH)2D]. Low 25OHD is associated with poor outcomes, possibly explained by its effect on bone and immunity. In this prospective, randomized double-blind, placebo-controlled study, we investigated the feasibility of normalizing 25OHD in prolonged (>10 days) critically ill patients and the effects thereof on 1,25(OH)2D, bone metabolism, and innate immunity. Twenty-four patients were included and compared with 24 matched healthy subjects. Patients were randomized to either intravenous bolus of 200 μg 25OHD followed by daily infusion of 15 μg 25OHD for 10 days, or to placebo. Parameters of vitamin D, bone and mineral metabolism, and innate immune function were measured. As safety endpoints, ICU length of stay and mortality were registered. Infusion of 25OHD resulted in a sustained increase of serum 25OHD (from median baseline 9.2 –16.1 ng/ml at day 10), which, however, remained below normal levels. There was no increase in serum 1,25(OH)2D but a slight increase in serum 24,25(OH)2D. Mineral homeostasis, innate immunity and clinical safety endpoints were unaffected. Thus, intravenous 25OHD administration during critical illness increased serum 25OHD concentrations, though less than expected from data in healthy subjects, which suggests illness-induced alterations in 25OHD metabolism and/or increased 25OHD distribution volume. The increased serum 25OHD concentrations were not followed by a rise in 1,25(OH)2D nor were bone metabolism or innate immunity affected, which suggests that low 25OHD and 1,25OHD levels are part of the adaptive response to critical illness.status: Published onlin

Performance of Pediatric Mortality Prediction Scores for PICU Mortality and 90-Day Mortality.

OBJECTIVES: The use of mortality prediction scores in clinical trials in the PICU is essential for comparing patient groups. Because of the decline in PICU mortality over the last decades, leading to a shift toward later deaths, recent trials use 90-day mortality as primary outcome for estimating mortality and survival more accurately. This study assessed and compared the performance of two frequently used PICU mortality prediction scores for prediction of PICU and 90-day mortality. DESIGN: This secondary analysis of the randomized controlled Early versus Late Parenteral Nutrition in the Pediatric Intensive Care Unit trial compared the discrimination (area under the receiver operating characteristic curve) and calibration of the Pediatric Index of Mortality 3 and the Pediatric Risk of Mortality III scores for prediction of PICU and 90-day mortality. SETTING: Three participating PICUs within academic hospitals in Belgium, the Netherlands, and Canada. PATIENTS: One-thousand four-hundred twenty-eight critically ill patients 0-17 years old. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Although Pediatric Index of Mortality 3 only includes information available at the time of PICU admission, thus before any intervention in the PICU, it showed good discrimination (area under the receiver operating characteristic curve, 0.894; 95% CI, 0.892-0.896) and good calibration (no deviation from the diagonal, p = 0.58) for PICU mortality. Pediatric Risk of Mortality III, which involves the worst values for the evaluated variables during the first 24 hours of PICU stay, was statistically more discriminant (area under the receiver operating characteristic curve, 0.920; 95% CI, 0.918-0.921; p = 0.04) but poor in calibration (significant deviation from the diagonal; p = 0.04). Pediatric Index of Mortality 3 and Pediatric Risk of Mortality III discriminated equally well between 90-day mortality and survival (area under the receiver operating characteristic curve, 0.867; 95% CI, 0.866-0.869 and area under the receiver operating characteristic curve, 0.882; 95% CI, 0.880-0.884, respectively, p = 0.77), but Pediatric Risk of Mortality III was not well calibrated (p = 0.04), unlike Pediatric Index of Mortality 3 (p = 0.34). CONCLUSIONS: Pediatric Index of Mortality 3 performed better in calibration for predicting PICU and 90-day mortality than Pediatric Risk of Mortality III and is not influenced by intervention or PICU quality of care. Therefore, Pediatric Index of Mortality 3 seems a better choice for use in clinical trials with 90-day mortality as primary outcome.status: publishe

Effect of early parenteral nutrition during paediatric critical illness on DNA methylation as a potential mediator of impaired neurocognitive development: a pre-planned secondary analysis of the PEPaNIC international randomised controlled trial.

BACKGROUND: Early use of parenteral nutrition in the paediatric intensive care unit (PICU) negatively affects development of executive functions, externalising behaviour, and visual-motor integration 2 years later, compared with omitting parenteral nutrition until PICU day 8 (late parenteral nutrition). The molecular basis of this finding is uncertain. We aimed to test the hypothesis that DNA methylation changes occur during critical illness and that early parenteral nutrition (or a specific macronutrient component hereof) contributes to these changes, which could explain its negative effects on neurocognitive development. METHODS: This pre-planned secondary analysis of the multicentre PEPaNIC trial (2012-18) included all patients with a last PICU day blood sample (n=825, aged 0-17 years at PICU admission) who were randomly allocated (1:1) to early parenteral nutrition or late parenteral nutrition, as compared with 352 demographically matched healthy children. Investigators were masked to treatment allocation. We used the Infinium Human MethylationEPIC BeadChip to determine the genome-wide peripheral blood leukocyte DNA methylation of 865 859 CpG sites, yielding high-quality results for 403 patients allocated to early parenteral nutrition and for 411 patients allocated to late parenteral nutrition. Applying a false discovery rate of less than 0·05, DNA methylation of patients on the last PICU day was compared with that of healthy children, after excluding all CpG sites differentially methylated upon PICU admission, because these reflected pre-admission conditions and altered leukocyte composition. We used bootstrapped multivariable linear and non-linear regression analyses to assess the effect of early parenteral nutrition versus late parenteral nutrition on illness-induced alterations in DNA methylation and to what extent differentially methylated CpG sites explained impaired neurocognitive development 2 years later. FINDINGS: During PICU stay, 159 CpG sites were methylated differently in patients admitted to the PICU than in healthy children, with mean effect sizes of 2·6% (SD 2·5) up to 21·6% (p<0·02). These differentially methylated CpG sites occurred in genes involved in brain development, plasticity, and signalling; neuronal differentiation, migration, and growth; metabolism; transcriptional regulation; physical development and locomotion; and several neurodegenerative and neuropsychiatric diseases. Early parenteral nutrition and, in particular, the dose of amino acids, independently contributed to the differential methylation of 37 (23%) of these 159 CpG sites (p=0·0001 to 0·050), which could explain the adverse effect of early parenteral nutrition on neurocognitive development at 2-year follow-up (R2 0·61 [SD 0·01]). INTERPRETATION: Early parenteral nutrition during paediatric critical illness altered DNA methylation, which suggests a plausible molecular basis for its negative effect on long-term neurocognitive development. Early administration of amino acids, rather than of glucose or lipids, mostly explained the aberrant DNA methylation-a finding that requires further investigation. FUNDING: European Research Council, Methusalem, Flanders Institute for Science and Technology, Research Foundation Flanders, Sophia Foundation, Stichting Agis Zorginnovatie, Erasmus Trustfonds, and European Society for Clinical Nutrition and Metabolism.status: Published onlin

Leukocyte telomere length in paediatric critical illness: Effect of early parenteral nutrition

__Background:__ Children who have suffered from critical illnesses that required treatment in a paediatric intensive care unit (PICU) have long-term physical and neurodevelopmental impairments. The mechanisms underlying this legacy remain largely unknown. In patients suffering from chronic diseases hallmarked by inflammation and oxidative stress, poor long-term outcome has been associated with shorter telomeres. Shortened telomeres have also been reported to result from excessive food consumption and/or unhealthy nutrition. We investigated whether critically ill children admitted to the PICU have shorter-than-normal telomeres, and whether early parenteral nutrition (PN) independently affects telomere length when adjusting for known determinants of telomere length. __Methods:__ Telomere length was quantified in leukocyte DNA from 342 healthy children and from 1148 patients who had been enrolled in the multicenter, randomised controlled trial (RCT), PEPaNIC. These patients were randomly allocated to initiation of PN within 24 h (early PN) or to withholding PN for one week in PICU (late PN). The impact of early PN versus late PN on the change in telomere length from the first to last PICU-day was investigated with multivariable linear regression analyses. __Results:__ Leukocyte telomeres were 6% shorter than normal upon PICU admission (median 1.625 (IQR 1.446-1.825) telomere/single-copy-gene ratio (T/S) units vs. 1.727 (1.547-1.915) T/S-units in healthy children (P < 0.0001)). Adjusted for potential baseline determinants and leukocyte composition, early PN was associated with telomere shortening during PICU stay as compared with late PN (estimate early versus late PN -0.021 T/S-units, 95% CI -0.038; 0.004, P = 0.01). Other independent determinants of telomere length identified in this model were age, gender, baseline telomere length and fraction of neutrophils in the sample from which the DNA was extracted. Telomere shortening with early PN was independent of post-randomisation factors affected by early PN, including longer length of PICU stay, larger amounts of insulin and higher risk of infection. __Conclusions:__ Shorter than normal leukocyte telomeres are present in critically ill children admitted to the PICU. Early initiation of PN further shortened telomeres, an effect that was independent of other determinants. Whether such telomere-shortening predisposes to long-term consequences of paediatric critical illness should be further investigated in a prospective follow-up study

Leukocyte telomere length in paediatric critical illness: effect of early parenteral nutrition

BACKGROUND: Children who have suffered from critical illnesses that required treatment in a paediatric intensive care unit (PICU) have long-term physical and neurodevelopmental impairments. The mechanisms underlying this legacy remain largely unknown. In patients suffering from chronic diseases hallmarked by inflammation and oxidative stress, poor long-term outcome has been associated with shorter telomeres. Shortened telomeres have also been reported to result from excessive food consumption and/or unhealthy nutrition. We investigated whether critically ill children admitted to the PICU have shorter-than-normal telomeres, and whether early parenteral nutrition (PN) independently affects telomere length when adjusting for known determinants of telomere length. METHODS: Telomere length was quantified in leukocyte DNA from 342 healthy children and from 1148 patients who had been enrolled in the multicenter, randomised controlled trial (RCT), PEPaNIC. These patients were randomly allocated to initiation of PN within 24 h (early PN) or to withholding PN for one week in PICU (late PN). The impact of early PN versus late PN on the change in telomere length from the first to last PICU-day was investigated with multivariable linear regression analyses. RESULTS: Leukocyte telomeres were 6% shorter than normal upon PICU admission (median 1.625 (IQR 1.446-1.825) telomere/single-copy-gene ratio (T/S) units vs. 1.727 (1.547-1.915) T/S-units in healthy children (P < 0.0001)). Adjusted for potential baseline determinants and leukocyte composition, early PN was associated with telomere shortening during PICU stay as compared with late PN (estimate early versus late PN -0.021 T/S-units, 95% CI -0.038; 0.004, P = 0.01). Other independent determinants of telomere length identified in this model were age, gender, baseline telomere length and fraction of neutrophils in the sample from which the DNA was extracted. Telomere shortening with early PN was independent of post-randomisation factors affected by early PN, including longer length of PICU stay, larger amounts of insulin and higher risk of infection. CONCLUSIONS: Shorter than normal leukocyte telomeres are present in critically ill children admitted to the PICU. Early initiation of PN further shortened telomeres, an effect that was independent of other determinants. Whether such telomere-shortening predisposes to long-term consequences of paediatric critical illness should be further investigated in a prospective follow-up study. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01536275 . Registered on 16 February 2012.status: publishe

Invasive Pneumococcal Disease in Children Younger than 5 years after the introduction of the Heptavalent Pneumococcal Conjugate Vaccine in Denmark.

1<p><b><i>Eligible:</i></b> child within the age group targeted for primary PCV7/PCV13 vaccination or catch-up program who presented an IPD episode before vaccination.</p>2<p><b><i>Not-eligible:</i></b> child outside the age group targeted for primary PCV7/PCV13 vaccination or catch-up program with PCV7.</p>3<p><b><i>PCV7-vaccinated:</i></b> children who presented an IPD episode after PCV7 immunization, regardless of the number of doses received, the time of onset of illness after vaccination and the age of immunization.</p>4<p><b><i>Other serotypes:</i></b> 6C, 8, 10B, 12F, 15B/C, 16F, 18F, 22F, 23F, 24F, 33F, 35B, 35F. No clear predominance of any serotype was observed. None of the patients presenting IPD due to PCV7 or PCV13 serotypes were vaccinated with PCV13.</p

IgG antibody concentrations and opsonophagocytic activity with type-specific polysaccharide in a child with PCV7-failure.

<p>The child presented with meningitis caused by serotype 23F after receiving 2 doses of PCV7. A serotype specific antibody value of 0.35 µg/mL was considered protective.</p>*<p>Percent inhibition of opsonophagocytic activity after addition of type-specific polysaccharide. NR: no result given incomplete (poor) killing of the sample.</p

Danish surveillance system of pediatric invasive pneumococcal disease (IPD) and pneumococcal conjugate vaccine (PCV)-failures.

<p>Cases of IPD caused by a serotype included in PCV7 or one of the additional serotypes included in PCV13 are identified among all IPD cases in children <5 years in order to explore possible cases of vaccine failure. PCV7 was administered in the national childhood immunization program free of charge from October 1, 2007 to April 19, 2010 and then PCV13 was offered. <i>CSF</i>: Cerebrospinal fluid; <i>NSR:</i> National Neisseria and Streptococcus Reference Center, Statens Serum Institut: SSI, <i>MBL:</i> Mannose-Binding Lectin, <i>RTI:</i> Respiratory Tract Infections, <i>WBC:</i> White Blood Cells.</p