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

Timing of enteral nutrition and parenteral nutrition in the PICU

The timing of nutrition support initiation has the potential to positively impact nutrition and clinical outcomes in infants and children with critical illness. Early enteral nutrition within 24-48 h and attainment of both a 60% energy and protein goal by the end of the first week of pediatric intensive care unit admission are reported to be significantly associated with improved survival in large observational studies. The results of one randomized controlled trial demonstrated increased morbidity in infants and children with critical illness assigned to early vs delayed supplemental parenteral nutrition. Observational studies in this population also suggest increased mortality with exclusive parenteral nutrition and worse nutrition outcomes when parenteral nutrition is delayed. Subsequently, current nutrition support guidelines recommend early enteral nutrition and avoidance of early parenteral nutrition, although the available evidence used to create the guidelines was inadequate to inform bedside nutrition support practice to improve outcomes. These guidelines are limited by the included studies with small numbers and heterogeneity of patients and research design that confound study outcomes and interpretation. This article provides a narrative review of the timing of nutrition support on outcomes in infants and children with critical illness, strategies to optimize timing and adequacy of nutrition support, and literature gaps, including the timing of parenteral nutrition initiation for children with malnutrition and those with contraindications to enteral nutrition and accurate measurement of energy requirements.

Changes in Telomere Length and Indicators of Oxidative Stress in Critically Ill Mechanically Ventilated Adults - A Pilot Study

BACKGROUND

Telomeres are structures at the end of chromosomes that shorten with each cell division. The purpose of this pilot project is to report changes in telomere length (T/S ratio), indicators of oxidative stress (serum protein carbonyl, vitamin C, GSH:GSSG, and total antioxidant capacity) from Intensive Care Unit (ICU) admission to ICU discharge, and to explore their association with ICU-related morbidities among critically ill mechanically ventilated adults.

METHODS

Blood was collected from mechanically ventilated patients (n = 25) at enrollment and within 48 hours of ICU discharge. Telomere length from peripheral blood mononuclear cells (PBMCs) was determined using RTqPCR. ELISAs were used to measure indicators of oxidative stress. Descriptive analysis, paired t-tests, and Pearson's correlations were performed.

RESULTS

Mean age was 62.0 ± 12.3 years, 28.6% were male, and 76.2% were White with disease severity using APACHE III (74.6 ± 24.6) and SOFA (7.6 ± 3.2). Mean T/S ratios shortened (ICU: 0.712, post-ICU: 0.683, p < 0.001, n = 19) and serum protein carbonyl increased (ICU: 7437 nmol/mg ± 3328, post-ICU: 10,254 nmol/mg ± 3962, p < 0.005) as did the oxidative stress index (protein carbonyl/GSH:GSSG, ICU: 1049.972 ± 420.923, post-ICU: 1348.971 ± 417.175, p = 0.0104). T/S ratio was positively associated with APACHE III scores (ICU: r = 0.474, post-ICU: r = 0.628, p < 0.05).

CONCLUSIONS

Pilot findings suggest that critical illness significantly correlates with telomere attrition, perhaps due to increased oxidative stress. Future larger and longitudinal studies investigating mechanisms of telomere attrition and associations with clinical outcomes are needed to identify potential modifiable factors for subsequent intervention to improve outcomes for critically ill patients.

The epigenetic legacy of ICU feeding and its consequences

PURPOSE OF REVIEW

Many critically ill patients face physical, mental or neurocognitive impairments up to years later, the etiology remaining largely unexplained. Aberrant epigenetic changes have been linked to abnormal development and diseases resulting from adverse environmental exposures like major stress or inadequate nutrition. Theoretically, severe stress and artificial nutritional management of critical illness thus could induce epigenetic changes explaining long-term problems. We review supporting evidence.

RECENT FINDINGS

Epigenetic abnormalities are found in various critical illness types, affecting DNA-methylation, histone-modification and noncoding RNAs. They at least partly arise de novo after ICU-admission. Many affect genes with functions relevant for and several associate with long-term impairments. As such, de novo DNA-methylation changes in critically ill children statistically explained part of their disturbed long-term physical/neurocognitive development. These methylation changes were in part evoked by early-parenteral-nutrition (early-PN) and statistically explained harm by early-PN on long-term neurocognitive development. Finally, long-term epigenetic abnormalities beyond hospital-discharge have been identified, affecting pathways highly relevant for long-term outcomes.

SUMMARY

Epigenetic abnormalities induced by critical illness or its nutritional management provide a plausible molecular basis for their adverse effects on long-term outcomes. Identifying treatments to further attenuate these abnormalities opens perspectives to reduce the debilitating legacy of critical illness.

Nutrition for the micro preemie: Beyond milk

Nutritional support is a fundamental component of the care of the extremely preterm infant, including the "micro preemie" (here defined as a baby born weighing less than 500 g), but goes beyond considerations of milk as a food. This is because milk from an infant's own mother, unlike currently available substitutes, additionally provides invaluable non-nutritive benefits. Nutritional support requires suitable devices or techniques to administer nutrients enterally or intravenously, products shown to be safe in preterm populations, and efficacy demonstrated in respect of important functional outcomes. Sadly, preterm feeding remains characterised by a deficit of evidence. In this chapter, we will briefly describe the history of preterm nutrition, discuss current enteral and parenteral practice, important evidence gaps, a summary of approaches for evaluating nutritional practice, and key considerations for future endeavour. Our discussion refers to all extremely preterm infants and it not confined to the micro preemie.

Early versus later initiation of parenteral nutrition for very preterm infants: a propensity score-matched observational study

OBJECTIVE

To evaluate the impact of timing of initiation of parenteral nutrition (PN) after birth in very preterm infants.

DESIGN

Propensity-matched analysis of data from the UK National Neonatal Research Database.

PATIENTS

65 033 babies <31 weeks gestation admitted to neonatal units in England and Wales between 2008 and 2019.

INTERVENTIONS

PN initiated in the first 2 days (early) versus after the second postnatal day (late). Babies who died in the first 2 days without receiving PN were analysed as 'late'.

MAIN OUTCOME MEASURES

The main outcome measure was morbidity-free survival to discharge. The secondary outcomes were survival to discharge, growth and other core neonatal outcomes.

FINDINGS

No difference was found in the primary outcome (absolute rate difference (ARD) between early and late 0.50%, 95% CI -0.45 to 1.45, p=0.29). The early group had higher rates of survival to discharge (ARD 3.3%, 95% CI 2.7 to 3.8, p<0.001), late-onset sepsis (ARD 0.84%, 95% CI 0.48 to 1.2, p<0.001), bronchopulmonary dysplasia (ARD 1.24%, 95% CI 0.30 to 2.17, p=0.01), treated retinopathy of prematurity (ARD 0.50%, 95% CI 0.17 to 0.84, p<0.001), surgical procedures (ARD 0.80%, 95% CI 0.20 to 1.40, p=0.01) and greater drop in weight z-score between birth and discharge (absolute difference 0.019, 95% CI 0.003 to 0.035, p=0.02). Of 4.9% of babies who died in the first 2 days, 3.4% were in the late group and not exposed to PN.

CONCLUSIONS

Residual confounding and survival bias cannot be excluded and justify the need for a randomised controlled trial powered to detect differences in important functional outcomes.

Born to Age: When Adult Congenital Heart Disease Converges With Geroscience

Advances in imaging, catheter-based interventions, congenital heart disease surgery, and clinical management of congenital heart disease (CHD) have yielded a dramatic change in age distribution of the CHD population. This implores clinicians and researchers to gain a better understanding of aging, as this will be the cornerstone to how we plan and manage this rapidly evolving group of patients. In this article, we first review the demographic changes in the CHD population and then describe the systemic complications of disease observed in young patients with CHD, following which we discuss general concepts in aging that may be transferable to the CHD population. Finally, we review inflammation and its potential impact on aging. We provide a new lens on aging in CHD and its functional consequences in CHD, with the goal of stimulating an exchange of knowledge between geroscientists and CHD.

Prenatal exposure to maternal psychological distress and telomere length in childhood

Telomere length (TL) is a biological marker of cellular aging, and shorter TL in adulthood is associated with increased morbidity and mortality risk. It is likely that these differences in TL are established long before adulthood, and there is growing evidence that TL can reflect prenatal experiences. Although maternal prenatal distress predicts newborn TL, it is unknown whether the relation between prenatal exposure to maternal distress and child TL persists through childhood. The purpose of the current longitudinal, prospective study is to examine the relation between prenatal exposure to maternal distress (perceived stress, depressive symptoms, pregnancy-related anxiety) and TL in childhood. Participants included 102 children (54 girls) and their mothers. Mothers' distress was assessed five times during pregnancy, at 12 weeks postpartum, and at the time of child telomere measurement between 6 and 16 years of age. Maternal distress during pregnancy predicted shorter offspring TL in childhood, even after accounting for postnatal exposure to maternal distress and other covariates. These findings indicate that maternal mental health predicts offspring TL biology later in childhood than previously observed. This study bolsters claims that telomere biology is subject to fetal programming and highlights the importance of supporting maternal mental health during pregnancy.

Septic shock as a trigger of arterial stress-induced premature senescence: A new pathway involved in the post sepsis long-term cardiovascular complications

BACKGROUND

Major adverse cardiovascular events among sepsis survivors is an emerging health issue. Because endothelial senescence leads to vascular dysfunction and atherothrombosis, sepsis could be associated to vascular stress-induced premature senescence and thus with long-term cardiovascular events.

MATERIALS & METHODS

Adult Wistar male rats were submitted to cecal ligation and puncture, or a SHAM operation. Markers of inflammation, oxidative stress and endothelial senescence were assessed at 3, 7 and 90 days (D), and vascular reactivity was assessed in conductance and resistance vessels at D90. Expression of proteins involved in senescence and inflammation was assessed by Western blot analysis and confocal microscopy, oxidative stress by dihydroethidium probing.

RESULTS

Pro-inflammatory endothelial ICAM-1 and VCAM-1 were up-regulated by three-fold in CLP vs. SHAM at D7 and remained elevated at D90. Oxidative stress followed a similar pattern but was detected in the whole vascular wall. Sepsis accelerated premature senescence in aorta vascular tissue as shown by the significant up-regulation of p53 and down-stream p21 and p16 senescent markers at D7, values peaking at D90 whereas the absence of significant variation in activated caspase-3 confirmed p53 as a prime inducer of senescence. In addition, p53 was mainly expressed in the endothelium. Sepsis-induced long-term vascular dysfunction was confirmed in aorta and main mesenteric artery, with a major alteration of the endothelial-dependent nitric oxide pathway.

CONCLUSIONS

Septic shock-induced long-term vascular dysfunction is associated with endothelial and vascular senescence. Our model could prove useful for investigating senotherapies aiming at reducing long-term cardiovascular consequences of septic shock.

Early or delayed parenteral nutrition for infants: what evidence is available?

PURPOSE OF REVIEW

To review the current evidence evaluating early versus delayed commencement of parenteral nutrition in infants.

RECENT FINDINGS

Recent studies in very premature infants (<32 weeks gestation) have shown that early commencement of parenteral nutrition immediately after birth improves physical growth. However, there are concerns that early use of very high dose of amino-acids (>3.5 g/kg/day immediately after birth) may cause metabolic acidosis, elevated blood urea, slower head growth and refeeding-hypophosphatemia syndrome. A recent multicentre randomized controlled trial found that commencement of parenteral nutrition within 24-h of admission increases the risk of infections and prolongs the duration of ventilation and ICU stay in full-term neonates, older infants and children. The study also found that delaying to day 8 of admission increased the risk of hypoglycaemia.

SUMMARY

Benefits of commencing parenteral nutrition on the first day of life appear to outweigh risks in very premature infants; however, it is prudent to avoid early very high doses of amino acids (>3.5 g/kg/day) in the first few days of life. In moderate to late preterm infants, if enteral feeds are not tolerated by 72 h, it is reasonable to commence parenteral nutrition. In full-term and older infants, it is preferable to avoid parenteral nutrition within 24 h of admission and consider delaying by further few days. Diligent monitoring of blood glucose, serum phosphate and other parameters is essential while on parenteral nutrition.

Early versus late parenteral nutrition for critically ill term and late preterm infants

BACKGROUND

Recently conducted randomised controlled trials (RCTs) suggest that late commencement of parenteral nutrition (PN) may have clinical benefits in critically ill adults and children. However, there is currently limited evidence regarding the optimal timing of commencement of PN in critically ill term and late preterm infants.

OBJECTIVES

To evaluate the benefits and safety of early versus late PN in critically ill term and late preterm infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (5 April 2019), MEDLINE Ovid (1966 to 5 April 2019), Embase Ovid (1980 to 5 April 2019), EMCare (1995 to 5 April 2019) and MEDLINE via PubMed (1966 to 5 April 2019). We searched for ongoing or recently completed clinical trials, and also searched the grey literature and reference lists of relevant publications.

SELECTION CRITERIA

We included RCTs comparing early versus late initiation of PN in term and late preterm infants. We defined early PN as commencing within 72 hours of admission, and late PN as commencing after 72 hours of admission. Infants born at 37 weeks' gestation or more were defined as term, and infants born between 34 and 36⁺⁶ weeks' gestation were defined as late preterm.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the trials, extracted the data and assessed the risk of bias. Treatment effects were expressed using risk ratio (RR) and risk difference (RD) for dichotomous outcomes and mean difference (MD) for continuous data. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

Two RCTs were eligible for inclusion. Data were only available from a subgroup (including 209 term infants) from one RCT in children (aged from birth to 17 years) conducted in Belgium, the Netherlands and Canada. In that RCT, children with medium to high risk of malnutrition were included if a stay of 24 hours or more in the paediatric intensive care unit (PICU) was expected. Early PN and late PN were defined as initiation of PN within 24 hours and after day 7 of admission to PICU, respectively. The risk of bias for the study was considered to be low for five domains and high for two domains. The subgroup of term infants that received late PN had significantly lower risk of in-hospital all-cause mortality (RR 0.35, 95% confidence interval (CI) 0.14 to 0.87; RD -0.10, 95% CI -0.18 to -0.02; number needed to treat for an additional beneficial outcome (NNTB) = 10; 1 trial, 209 participants) and neonatal mortality (death from any cause in the first 28 days since birth) (RR 0.29, 95% CI 0.10 to 0.88; RD -0.09, 95% CI -0.16 to -0.01; NNTB = 11; 1 trial, 209 participants). There were no significant differences in rates of healthcare-associated blood stream infections, growth parameters and duration of hospital stay between the two groups. Neurodevelopmental outcomes were not reported. The quality of evidence was considered to be low for all outcomes, due to imprecision (owing to the small sample size and wide confidence intervals) and high risk of bias in the included studies.

AUTHORS' CONCLUSIONS

Whilst late commencement of PN in term and late preterm infants may have some benefits, the quality of the evidence was low and hence our confidence in the results is limited. Adequately powered RCTs, which evaluate short-term as well as long-term neurodevelopmental outcomes, are needed.

Telomere Length Changes during Critical Illness: A Prospective, Observational Study

Objective: evaluation of telomere length change in acutely ill adult patients. Design: Blood samples were drawn on the first and seventh day of intensive care unit (ICU) stay to assess telomere length using a polymerase chain reaction (PCR)-based technique. Demographic data collected included age, weight, admission diagnosis, baseline laboratory values (pH, C- reactive protein (CRP), serum albumin level, white blood cell count (WBC) count, platelet count), and baseline SOFA and APACHE II scores. Additional data collected during the ICU stay included a repeated WBC count, the presence of positive blood cultures and outcome data, including death in the ICU or following discharge, whether ventilated or not at ICU discharge, and destination following discharge, i.e., medical ward or rehabilitation. Setting: General ICU in tertiary hospital. Patients: Forty patients admitted to the ICU within 72 h of hospital admission suffering from an acute illness were included in this prospective, observational study. Main results: Of the 40 patients studied, telomere shortening was noted in 21, telomere lengthening in 11, and no significant change in the other eight. The age of patients demonstrating telomere shortening was statistically significantly younger (45.4 vs. 61.5 years, p < 0.023) compared to those showing increased telomere length. In addition, a significant correlation was observed between the difference in telomere length and the corresponding difference in WBC count (telomere shortening was associated with a decreased WBC count and vice versa). A trend toward shortening was seen in patients with sepsis (p = 0.07). No significant correlations were found for any other demographic or outcome parameter and changes in telomere length. Conclusion: Changes in telomere length, both shortening and lengthening, were evident in the acute setting, but no associations between such changes with outcome were noted. Further studies in more homogeneous groups of patients appear to be warranted.

Paediatric parenteral nutrition: current issues

Parenteral nutrition transformed the prognosis for infants and children with intestinal failure. Soon after its introduction into clinical care 50 years ago, parenteral nutrition was also rapidly adopted for use in the preterm infant, where immaturity of gastrointestinal motor function precluded enteral feeding. Preterm infants subsequently became the single largest group of patients to be fed in this way. Although the development of scientific knowledge and the lessons of clinical experience have reduced the risk of complications, some of the problems and difficulties associated with this form of nutritional support remain challenging. These include central venous catheter-related sepsis, thrombosis, liver disease, bone disease and metabolic disturbance. In an initiative to promote best practice, guidelines on parenteral nutrition were first published by the European Society for Paediatric Gastroenterology, Hepatology and Nutrition and collaborating organisations in 2005. These were constructed following a thorough review of the scientific literature, allowing a series of evidence-based recommendations to be made. The exercise was repeated just over 10 years later and updated guidelines published in 2018. This review summarises key elements from the new guideline, with a focus on what has changed since 2005.

International survey of De-implementation of initiating parenteral nutrition early in Paediatric intensive care units

BACKGROUND

Initiating parenteral nutrition (PN) within 24 h in critically ill children is inferior to withholding PN during the first week, as was found in the PEPaNIC study. The aims of this study were to investigate de-implementation of early initiation of PN at PICUs worldwide, and to identify factors influencing de-implementation.

METHODS

A cross-sectional online survey was conducted (May - October 2017), consisting of 41 questions addressing current PN practices, the degree of de-implementation, and factors affecting de-implementation.

RESULTS

We analysed 81 responses from 39 countries. Of these 81 respondents, 53 (65%) were aware of the findings of the PEPaNIC study, and 43 (53%) have read the article. In these 43 PICUs, PN was completely withheld during the first week in 10 PICUs, of which 5 already withheld PN (12%), and 5 de-implemented early initiation of PN (12%). Partial de-implementation was reported by 17 (40%) and no de-implementation by 16 (37%). Higher de-implementation rates were observed when the interpreted level of evidence and grade of recommendation of PEPaNIC was high. Predominant reasons for retaining early initiation of PN were concerns on withholding amino acids, the safety in undernourished children and neonates, and the long-term consequences. Furthermore, the respondents were waiting for updated guidelines.

CONCLUSIONS

One year after the publication of the PEPaNIC trial, only two-thirds of the respondents was aware of the study results. Within this group, early initiation of PN was de-implemented completely in 12% of the PICUs, while 40% asserted partial de-implementation. Increasing the awareness, addressing the intervention-specific questions and more frequently revising international guidelines might help to accelerate de-implementation of ineffective, unproven or harmful healthcare.

Early Supplemental Parenteral Nutrition in Critically Ill Children: An Update

In critically ill children admitted to pediatric intensive care units (PICUs), enteral nutrition (EN) is often delayed due to gastrointestinal dysfunction or interrupted. Since a macronutrient deficit in these patients has been associated with adverse outcomes in observational studies, supplemental parenteral nutrition (PN) in PICUs has long been widely advised to meeting nutritional requirements. However, uncertainty of timing of initiation, optimal dose and composition of PN has led to a wide variation in previous guidelines and current clinical practices. The PEPaNIC (Early versus Late Parenteral Nutrition in the Pediatric ICU) randomized controlled trial recently showed that withholding PN in the first week in PICUs reduced incidence of new infections and accelerated recovery as compared with providing supplemental PN early (within 24 hours after PICU admission), irrespective of diagnosis, severity of illness, risk of malnutrition or age. The early withholding of amino acids in particular, which are powerful suppressors of intracellular quality control by autophagy, statistically explained this outcome benefit. Importantly, two years after PICU admission, not providing supplemental PN early in PICUs did not negatively affect mortality, growth or health status, and significantly improved neurocognitive development. These findings have an important impact on the recently issued guidelines for PN administration to critically ill children. In this review, we summarize the most recent literature that provides evidence on the implications for clinical practice with regard to the use of early supplemental PN in critically ill children.

Long-term developmental effects of withholding parenteral nutrition for 1 week in the paediatric intensive care unit: a 2-year follow-up of the PEPaNIC international, randomised, controlled trial

BACKGROUND

The paediatric early versus late parenteral nutrition in critical illness (PEPaNIC) multicentre, randomised, controlled trial showed that, compared with early parenteral nutrition, withholding supplemental parenteral nutrition for 1 week in the paediatric intensive care unit (PICU; late parenteral nutrition) reduced infections and accelerated recovery from critical illness in children. We aimed to investigate the long-term impact on physical and neurocognitive development of early versus late parenteral nutrition.

METHODS

In this preplanned 2-year follow-up study, all patients included in the PEPaNIC trial (which was done in University Hospitals Leuven, Belgium; Erasmus Medical Centre-Sophia Children's Hospital, Rotterdam, Netherlands; and Stollery Children's Hospital, Edmonton, AB, Canada) were approached for possible assessment of physical and neurocognitive development compared with healthy children who were matched for age and sex, and who had never been admitted to a neonatal ICU or a PICU. Assessed outcomes comprised anthropometric data; health status; parent-reported or caregiver-reported executive functions and emotional and behavioural problems; and tests for intelligence, visual-motor integration, alertness, motor coordination, inhibitory control, cognitive flexibility, and memory. To address partial responses among the children tested, we did multiple data imputation by chained equations before univariable and multivariable linear and logistic regression analyses adjusted for risk factors. This trial is registered with ClinicalTrials.gov, number NCT01536275.

FINDINGS

At the 2-year follow-up, 60 (8%) of 717 children who received late parenteral nutrition and 63 (9%) of 723 children who received early parenteral nutrition had died (p=0·81). 68 (9%) of 717 children who received late and 91 (13%) of 723 children who received early parenteral nutrition were too disabled for neurocognitive assessment (p=0·059), and 786 patients (395 assigned to late and 391 assigned to early parenteral nutrition) consented for testing. 786 patients and 405 healthy control children underwent long-term outcome testing between Aug 4, 2014, and Jan 19, 2018, and were included in the imputation model for subsequent multivariable analyses. Late parenteral nutrition did not adversely affect anthropometric data, health status, or neurological functioning, and improved parent-reported or caregiver-reported executive functioning (late vs early parenteral nutrition β estimate -2·258, 95% CI -4·012 to -0·504; p=0·011), more specifically inhibition (-3·422, -5·171 to -1·673; p=0·0001), working memory (-2·016, -3·761 to -0·270; p=0·023), and meta-cognition (-1·957, -3·694 to -0·220; p=0·027). Externalising behavioural problems (β estimate -1·715, 95% CI -3·325 to -0·106; p=0·036) and visual-motor integration (0·468, 0·087 to 0·850; p=0·016) were also improved in the late parenteral nutrition group compared with the early parenteral nutrition group. After Bonferroni correction for multiple comparisons, the effect on inhibitory control remained significant (p=0·0001).

INTERPRETATION

Withholding early parenteral nutrition for 1 week in the PICU did not negatively affect survival, anthropometrics, health status, and neurocognitive development, and improved inhibitory control 2 years after PICU admission.

FUNDING

European Research Council Advanced Grant, Methusalem programme provided by the Flemish Government, Flemish Agency for Innovation by Science and Technology (IWT), Research Foundation Flanders (FWO), Sophia Children's Hospital Foundation (SSWO), Stichting Agis Zorginnovatie, Erasmus Trustfonds, and European Society for Parenteral and Enteral Nutrition (ESPEN) research grant.