Patients admitted to the intensive care unit (ICU) after major surgery frequently develop anorexia, feeding intolerance, and hyperglycaemia in response to the severe stress. Although observational studies have associated accumulation of a caloric deficit with poor outcome, randomised controlled trials (RCTs) have shown that early nutrition support induces dose-dependent harm in ICU patients, which has been attributed to aggravation of hyperglycaemia and associated metabolic damage, as well as suppressed cellular repair mechanisms. Hence, early full nutrition support, including early parenteral nutrition, should be avoided. The ideal blood glucose control target depends on the context. Tight blood glucose control (TGC) may be superior, but should only be performed when it can be achieved with a protocol that avoids hypoglycaemia. Safe TGC requires a protocol that includes regular, accurate blood glucose measurements and avoidance of insulin boluses. In the absence of such protocol, at least severe hyperglycaemia and hypoglycaemia should be avoided.

Critically ill patients requiring treatment in the intensive care unit (ICU) suffer from muscle weakness that persists for years. As compared with healthy subjects, skeletal muscle of patients biopsied five years post-ICU revealed an abnormal transcriptome partially associated with poor muscle strength. We now hypothesized that skeletal muscle of long-term ICU survivors is "epigenetically aged", as determined by a muscle-specific epigenetic clock, and that such accelerated epigenetic aging contributes to their long-term muscle weakness. Muscle DNA-methylation data from former ICU patients at 5-year follow-up (N = 118) and healthy controls (N = 160), aged 18-89 years, were analyzed by the MEATv2 epigenetic clock. First, epigenetic age (DNAmAge), epigenetic minus chronological age (AADiff) and epigenetic age acceleration (AAResid) were compared between 97 former patients and 97 controls, propensity score-matched for age and sex. Next, the impact of any muscle-specific epigenetic aging of ICU survivors was investigated, via multivariable models, as a potential contributor to the altered transcriptome and reduced muscle strength. Former ICU patients showed a significantly higher muscle DNAmAge, AADiff, and AAResid than matched controls. In adjusted models, higher muscle DNAmAge, AADiff, or AAResid did not substantially contribute to differentially expressed muscle RNAs in former patients as compared with controls and was not associated with the poor long-term muscle strength. In conclusion, five years after ICU discharge, former patients showed accelerated epigenetic aging in skeletal muscle. However, the muscle-specific epigenetic clock did not capture molecular changes that are associated with long-term muscle weakness, which highlights the need for other muscle-specific biological predictors of age-related physical impairment. Trail Registration: ClinicalTrials.gov: NCT00512122.

Abstract Background Many children admitted to a pediatric intensive-care-unit (PICU) show impaired physical function years later. Testing physical function clinically is time-consuming and expensive, hampering routine follow-up. We investigated whether subjective parent-reported physical health-related quality-of-life correlates with and may replace objectively measured physical function of former PICU-patients. Methodology This secondary analysis of the PEPaNIC-RCT included 517 former PICU-patients with physical function tests and parent-reported health-related quality-of-life 4 years later. Parents scored physical function, bodily pain, general health and physical role functioning with questionnaires. Physical function tests included handgrip-strength, timed up-and-go-test, 6-minute-walk-test, and accelerometry. Questionnaire-items and test-scores were correlated with Pearson/Spearman correlation. Results Parent-reported physical function correlated moderately with daily time in sedentary state (ρ=-0.300, p < 0.0001), daily sedentary bouts (R=-0.330, p < 0.0001) and daily steps/hour monitored (R = 0.303, p < 0.0001), and weakly with handgrip-strength, physical activity energy expenditure, time in certain activity-intensity and daily steps (ρ/R = 0.185–0.289, p ≤ 0.019). Parent-reported general health (ρ/R=-0.228 to 0.296, p ≤ 0.033) and physical role functioning (ρ/R=-0.269 to 0.240, p ≤ 0.038) correlated weakly with roughly the same measured physical functions. Parent-reported bodily pain correlated weakly with daily sedentary bouts (R=-0.143, p = 0.024) and daily steps/hour monitored (R = 0.145, p = 0.022). Correlations among physical function test scores were mostly weak. Conclusions Several aspects of subjective parent-reported physical health-related quality-of-life correlated with former PICU-patients’ performance on physical function tests. The mostly weak strength of the correlations suggest that interrogated physical function cannot simply replace clinical testing. Nevertheless, when resources for clinical testing are lacking, interrogating physical function could still be valuable to get an idea about long-term physical functioning.

The PEPaNIC RCT showed that early supplementation of insufficient enteral nutrition by parenteral nutrition (early-PN) worsened outcome of critically ill children as compared with withholding PN for 1 week (late-PN). The best timing to initiate nutritional support in the pediatric intensive care unit (PICU) remains unclear. In adults, declining phosphate levels may identify patients who are particularly harmed by early-PN. We therefore assessed whether early hypophosphatemia in critically ill children may indicate metabolic intolerance to nutrition. In this secondary analysis of the PEPaNIC RCT (n = 1440), we investigated whether development of hypophosphatemia statistically interacts with the randomized intervention for its impact on clinical outcome, adjusting for baseline risk factors. Outcomes of interest included the incidence of new infections and the duration of PICU dependency as primary endpoints, 90-day mortality as safety endpoint, and duration of mechanical ventilation and of hospital stay as secondary endpoints. Subsequently, the impact of early-PN vs. late-PN in patients with and without early hypophosphatemia was assessed. Analyses were performed for phosphate abnormalities on PICU day 1 and 2, with and without imputing 20.3

BACKGROUND:Critically ill patients requiring intensive care unit (ICU) admission suffer from muscle weakness that persists for years. Recently, altered RNA expression was documented in muscle of former ICU patients 5 years after critical illness that suggested disrupted mitochondrial function, disturbed lipid metabolism and fibrosis, of which many associated with the former patients' long-term loss of muscle strength. We hypothesized that abnormal DNA methylation detectable years after critical illness associates with these abnormal RNA expression patterns, as a potential biological basis for the persistent loss of muscle strength. METHODS:Genome-wide DNA methylation was assessed (Infiniumv2-HumanMethylationEPIC-BeadChips) in skeletal muscle biopsies from 118 former ICU patients harvested 5 years after critical illness (79.6% male, median 58 years, median BMI 27.3 kg/m2) and 30 controls who never required ICU admission (76.7% male, median 61 years, median BMI 26.4 kg/m2). Differentially methylated positions (DMPs) in former patients versus controls were identified, adjusting for age, sex, and BMI (minfi-package in R, Benjamini-Hochberg false-discovery-rate < 0.05), followed by pathway over-representation of affected genes. Spearman correlations between DMP methylation and RNA expression were compared among groups of RNA with Z-test and Kolmogorov-Smirnov test. Risk factors for abnormal DNA methylation were identified with multivariable linear regression. RESULTS:As compared with controls, former ICU patients showed 7379 DMPs (average difference 2.6% ranging up to 24.9%). They were associated with 1334 unique genes, enriched for muscle contraction, vascular development, cell differentiation and signal transduction. DMPs correlated more strongly with differentially expressed RNAs (DERNAs) than with non-differentially expressed RNAs (18.1% vs. 1.7% correlations with |rho| > 0.3, p < 2.2 × 10-16). Such correlations were more abundant among DERNAs associated with reduced muscle strength vs. those not associated (24.4% vs. 12.5%), also within the previously identified disrupted pathways (mitochondrial function 23.3% vs. 10.9%, lipid metabolism 15.9% vs. 7.2%, fibrosis 44.3% vs. 5.8%, all p < 2.2 × 10-16). Older age, female sex, in-ICU treatment with glucocorticoids, benzodiazepines, early parenteral nutrition and opioids and insulin and antipsychotic medication at follow-up were most notably associated with more abnormal DNA methylation. CONCLUSIONS:Abnormal DNA methylation in muscle biopsied 5 years after critical illness associated with long-term altered RNA expression that has been linked to lower muscle strength. These data suggest a possible epigenetic basis for this long-term sequel after critical illness. Abnormal DNA methylation was also found to associate with (possibly) avoidable risk factors during and after ICU stay. These findings may open perspectives for prevention and possibly treatment of long-term muscle weakness after critical illness.

Critically ill children requiring treatment in a pediatric intensive care unit (PICU) suffer from anorexia and/or feeding intolerance. The resulting macronutrient deficit associates with poor outcome. Until recently, this association formed the basis for initiating enteral or parenteral feeding early to improve outcome. The multicenter “Early-versus-Late-Parenteral-Nutrition-in-the-Pediatric-Intensive-Care-Unit” randomized controlled trial (PEPaNIC-RCT) addressed whether this association is causal. It showed that early supplementation of insufficient/contraindicated enteral nutrition with parenteral nutrition, as compared with accepting a macronutrient deficit throughout the first week in the PICU, did not improve outcome. On the contrary, it caused more infections and prolonged organ support and PICU stay, and adversely affected neurodevelopmental outcomes 2 and 4 years later. Harm was present in all subgroups and appeared explained by the macronutrient dose, more specifically the amino-acid dose, not lipid or glucose doses. These findings corroborated results from large-scale adult RCTs. Mechanisms of harm from early enhanced nutrition comprised suppressed cellular repair pathways like autophagy and ketogenesis, suppressed illness-induced alterations in thyroid hormone metabolism, more iatrogenic hyperglycemia, increased urea cycle activity through anabolic resistance, and induction of epigenetic modifications that mediate longer-term developmental impairments.These results came unexpected to many pediatric intensivists. Hence, the paradigm has only slowly begun to shift toward more restrictive macronutrient administration in the acute phase of critical illness. Benefits of early fasting responses have become clear, provided micronutrients are given to prevent deficiencies and refeeding syndrome. These insights open perspectives for studies investigating novel nutritional strategies to activate fasting-induced cellular repair while avoiding prolonged starvation.

ABSTRACT Background Suppression of the peroxisome proliferator‐activated receptor alpha (PPARα) has been related to poor outcomes in sepsis and may compromise ketogenesis during critical illness. Infusion of 3‐hydroxybutyrate (3HB) was shown to attenuate muscle weakness in septic mice. We hypothesise that endogenous ketogenesis induced by pharmacological PPARα activation, either alone or combined with ketogenic nutrition, is safe and can also mitigate muscle weakness in septic mice. Methods In a fluid‐resuscitated, antibiotic‐treated mouse model of prolonged sepsis, we first (Study 1) assessed the safety and effectiveness (impact on ketosis and muscle weakness) of the PPARα agonist pemafibrate (1 mg/kg/d, n = 16), versus placebo (n = 15) combined with standard balanced parenteral nutrition (PN), composed of glucose, amino acids and long‐chain triglycerides (LCT) (balanced‐TPN). We subsequently (Study 2) evaluated the impact of pemafibrate combined with four types of PN on ketosis and muscle weakness: balanced‐TPN (n = 18), TPN with extra LCTs (TPN + LCT, n = 18), low‐dose pure LCT emulsion (Low‐LCT, n = 16) and high‐dose pure LCT emulsion (High‐LCT n = 18). Carbohydrates and amino acids were omitted in the pure LCT groups. Healthy control mice (HC, n = 19) served as controls. Ex vivo muscle force was measured as the primary outcome. Metabolic, inflammatory and microstructural parameters were assessed on plasma and in muscle and liver tissue by targeted metabolomics, gene expression analysis, biochemical and metabolite assays and histological assessment. Results Pemafibrate treatment with balanced‐TPN upregulated hepatic gene expression of PPARα (Ppara) and its downstream genes (Cd36, Cpt1a, Atgl, Acadl, Hadha, Acox1, and Hmgcs2) (p < 0.0001) and was well tolerated. However, pemafibrate treatment with the use of balanced‐TPN administration did not induce detectable ketosis or improve muscle weakness. In combination with pemafibrate, TPN + LCT also did not induce ketosis, nor did it affect muscle weakness. In contrast, 3‐hydroxybutyrate plasma concentrations increased with High‐LCT (95‐fold) and Low‐LCT (10‐fold) (p < 0.0001) in combination with pemafibrate, yet muscle force declined further (High‐LCT 25.0%, Low‐LCT 10.7% of HC, p < 0.0001). Blood glucose was lowered with pure High‐LCT and Low‐LCT (High‐LCT 86.9%, Low‐LCT 55.1% of TPN, p < 0.05), while plasma lipids and LC‐carnitines were increased (p < 0.0001). Markers of hepatic protein catabolism were upregulated with High‐LCT and Low‐LCT (p < 0.007), while muscle glycolytic intermediates (p < 0.0001) and ATP levels (p < 0.0001) were depleted. Conclusions In septic mice, pemafibrate combined with balanced‐TPN or lipid‐rich TPN induced PPARα activation but did not result in ketosis nor affect muscle weakness. Pemafibrate combined with pure LCTs induced ketosis in sepsis but worsened muscle weakness, possibly explained by muscular bioenergetic failure.

Pediatric critical illness can disrupt circadian rhythms, potentially leading to long-term deficits in growth, neurocognition, and behavior. Disturbances in circadian rhythms have been associated with altered gene expression and DNA methylation. We investigated long-term DNA methylation alterations in circadian entrainment and clock genes in children previously admitted to the pediatric intensive care unit (PICU), the influence of parenteral nutrition (PN) timing hereon and their associations with long-term health outcomes. This study is a secondary analysis of the PEPaNIC randomized controlled trial (RCT) and its two-year follow-up. The PEPaNIC-RCT randomized critically ill children to early initiation of supplemental PN within the first 24 h or its omission in the first week of PICU admission. DNA methylation of 127 circadian entrainment and clock genes was studied in buccal mucosa DNA of former PICU patients (n = 818) and matched healthy children (n = 392) at the two-year follow-up using Infinium® HumanMethylation EPIC BeadChips. Multivariable linear models were used to identify differential methylation between former patients and controls and their association with randomization group and outcomes at two-year follow-up. Former PICU patients showed 61 differentially methylated CpG sites (DMPs) within 34 of the genes, with 60 (98.4

Critically ill patients requiring intensive care unit (ICU) admission suffer from muscle weakness that persists for years, compromising quality-of-life. The pathophysiology of this long-term weakness remains unclear. We hypothesized that former ICU-patients show a long-term abnormal RNA-expression profile, which may contribute to lower long-term strength and for which modifiable risk factors can be identified. This pre-planned secondary analysis of the EPaNIC-trial compared muscle transcriptomes of 115 former ICU-patients 5 years after critical illness and 30 matched controls with RNA-sequencing, followed by pathway over-representation and differential co-expression analyses of the differentially expressed RNAs. We used multivariable linear regression analyses to identify which of the abnormal RNA-expressions associated with the long-term muscle strength of the patients and to identify potential risk factors for the abnormal RNA-expressions. In former patients, 234 down-regulated and 116 up-regulated RNAs were identified after adjustment for age, sex, and BMI. Pathway over-representation and further molecular and histological analyses indicated impaired mitochondrial energy metabolism, disturbed lipid metabolism, and increased collagen formation/fibrosis in former patients. Abnormal muscle RNA-expression in former patients correlated with lower long-term muscle strength. Several treatments given in-ICU and at 5-year follow-up associated with abnormal RNA-expression, most notably in-ICU early parenteral nutrition (early PN) and glucocorticoid use. Abnormal RNA-expression profiles 5 years after critical illness suggest disrupted mitochondrial function, disturbed lipid metabolism, and fibrosis, associated with lower long-term muscle strength and partly attributable to possibly avoidable risk factors. These findings open perspectives for prevention and possibly treatment of long-term muscle weakness after critical illness. ClinicalTrials.gov-NCT00512122, July 31, 2007.

Intensive care unit acquired weakness (ICUAW) is common in critically ill patients, contributing to substantial morbidity. Major trials and novel mechanistic findings published over the past years have advanced knowledge for the prevention and treatment of ICUAW. To streamline future research priorities, a multinational, interdisciplinary group of ICU clinicians, researchers, and people with lived experience convened to develop this evidence-based research agenda. Using a stepwise process including a systematic review with meta-analysis, two expert panel meetings, and a two-round modified Delphi method, we identified the top ten research priorities for ICUAW. Our report highlights the lack of reliable prognostic markers and mechanistic understanding that limit early diagnosis and treatment. Current evidence to treat ICUAW supports enhanced physical rehabilitation versus no rehabilitation, while higher dose enterally-delivered protein alone does not improve patient outcomes. However, the direct effects on muscles or appropriate dosing for patients with comorbidities remain largely unknown. The proposed ten key priority research questions integrate pathophysiology, diagnostics, treatment, and follow-up and emphasise personalised medicine and patient-centred outcomes over the continuum of recovery. Future research should focus on early prognostic markers, mechanisms of ICUAW, and identification of treatment responders allowing individualised dosing strategies tailored across the recovery trajectory. Defining meaningful outcomes, improving follow-up care, and integrating patient, family and caregiver priorities are essential. Advancing this agenda will require interdisciplinary collaboration and the use of emerging methods, including artificial intelligence, to support personalised and effective ICUAW care.

Early identification of potential high cost and high need patients on the ICU may assist in the development of targeted protocols, which allows proper resource utilization and initialization of preventive care. Weakness acquired in the ICU developed within the first week is an independent predictor of both short and long-term adverse outcomes, nonetheless early prediction is challenging. We aimed to develop and validate a machine learning model for ICU acquired-weakness (ICU-AW), using data readily available within the first 24 h of ICU admission. Patients from the EPaNIC trial (NCT00512122, N = 4640) who were assessed for muscle weakness at day 9 (IQR 8–13), after ICU-admission, using the Medical Research Council (MRC) sum. Patients are diagnosed with ICU-AW if their MRC is higher than 48. The final subset contains N = 600. Our models were internally validated using 100 repetitions of fivefold cross validation. We compared three predictive models: (i) a random forest and (ii) a logistic regression model built using descriptors available at day 1, (iii) a random forest using only APACHE II as a descriptor. Both random forests contain 150 trees. The training set comprised 600 patients where the incidence of ICU-AW was 38.6

Background Critically ill children suffer from impaired physical/neurocognitive development 2 years later. Glucocorticoid treatment alters DNA methylation within the hypothalamus–pituitary–adrenal (HPA) axis which may impair normal brain development, cognition and behaviour. We tested the hypothesis that paediatric-intensive-care-unit (PICU) patients, sex- and age-dependently, show long-term abnormal DNA methylation within the HPA-axis layers, possibly aggravated by glucocorticoid treatment in the PICU, which may contribute to the long-term developmental impairments. Results In a pre-planned secondary analysis of the multicentre PEPaNIC-RCT and its 2-year follow-up, we identified differentially methylated positions and differentially methylated regions within HPA-axis genes in buccal mucosa DNA from 818 former PICU patients 2 years after PICU admission ( n = 608 no glucocorticoid treatment; n = 210 glucocorticoid treatment) versus 392 healthy children and assessed interaction with sex and age, role of glucocorticoid treatment in the PICU and associations with long-term developmental impairments. Adjusting for technical variation and baseline risk factors and correcting for multiple testing (false discovery rate < 0.05), former PICU patients showed abnormal DNA methylation of 26 CpG sites (within CRHR1, POMC, MC2R, NR3C1, FKBP5, HSD11B1, SRD5A1, AKR1D1, DUSP1, TSC22D3 and TNF ) and three DNA regions (within AVP, TSC22D3 and TNF ) that were mostly hypomethylated. These abnormalities were sex-independent and only partially age-dependent. Abnormal methylation of three CpG sites within FKBP5 and one CpG site within SRD5A1 and AKR1D1 was partly attributable to glucocorticoid treatment during PICU stay. Finally, abnormal methylation within FKBP5 and AKR1D1 was most robustly associated with long-term impaired development. Conclusions Two years after critical illness in children, abnormal methylation within HPA-axis genes was present, predominantly within FKBP5 and AKR1D1 , partly attributable to glucocorticoid treatment in the PICU, and explaining part of the long-term developmental impairments. These data call for caution regarding liberal glucocorticoid use in the PICU.

Background and objectiveCritically ill children may suffer from impaired neurocognitive functions years after ICU (intensive care unit) discharge. To assess neurocognitive functions, these children are subjected to a fixed sequence of tests. Undergoing all tests is, however, arduous for former pediatric ICU patients, resulting in interrupted evaluations where several neurocognitive deficiencies remain undetected. As a solution, we propose using machine learning to predict the optimal order of tests for each child, reducing the number of tests required to identify the most severe neurocognitive deficiencies.MethodsWe have compared the current clinical approach against several machine learning methods, mainly multi-target regression and label ranking methods. We have also proposed a new method that builds several multi-target predictive models and combines the outputs into a ranking that prioritizes the worse neurocognitive outcomes. We used data available at discharge, from children who participated in the PEPaNIC-RCT trial (ClinicalTrials.gov-NCT01536275), as well as data from a 2-year follow-up study. The institutional review boards at each participating site have also approved this follow-up study (ML8052; NL49708.078; Pro00038098).ResultsOur proposed method managed to outperform other machine learning methods and also the current clinical practice. Precisely, our method reaches approximately 80% precision when considering top-4 outcomes, in comparison to 65% and 78% obtained by the current clinical practice and the state-of-the-art method in label ranking, respectively.ConclusionsOur experiments demonstrated that machine learning can be competitive or even superior to the current testing order employed in clinical practice, suggesting that our model can be used to severely reduce the number of tests necessary for each child. Moreover, the results indicate that possible long-term adverse outcomes are already predictable as early as at ICU discharge. Thus, our work can be seen as the first step to allow more personalized follow-up after ICU discharge leading to preventive care rather than curative.

BACKGROUND & AIMS:Critically ill children are at risk of micronutrient deficiencies, which might lead to poor clinical outcomes. However, the interpretation of micronutrient concentrations in plasma is complicated due to age-dependent and critical illness-dependent changes. Certain red blood cell (RBC) concentrations might reflect the overall body status more reliably than plasma levels in the presence of systemic inflammatory response. This study longitudinally examined micronutrient concentrations in both plasma and RBC in critically ill children. METHODS:This secondary analysis of the PEPaNIC RCT investigated the impact of early versus late initiation of parenteral macronutrient supplementation in critically ill children. All children received micronutrients when EN was insufficient (<80 % energy requirements). Blood samples were obtained on days 1, 3, 5 and 7 of Paediatric Intensive Care Unit (PICU) admission. Inductively coupled plasma mass spectrometry was used to measure zinc, selenium, and copper in plasma and selenium, copper, and magnesium in RBCs. Plasma magnesium was measured with colorimetric detection. Micronutrient concentrations were compared with age-specific reference values in healthy children and expressed using Z-scores. Changes in micronutrient concentrations over time were examined using the Friedman and post hoc Wilcoxon signed-rank tests. RESULTS:For 67 critically ill children, median (Q1; Q3) age 9.5 (5.5; 13.2) years, PIM3 score -2.3 (-3.1; -0.8), samples were available at various time points during their PICU stay. For 22 patients, longitudinal samples were available. On day 1, the median plasma Z-score for zinc was -5.2 (-5.2; -2.9), copper -1.6 (-2.9; -0.2), selenium -2.6 (-3.8; -1.0), magnesium -0.2 (-1.6; 1.3), and median RBC Z-score for copper was 0.5 (-0.1; 1.3), selenium -0.3 (-1.1; 0.7), magnesium 0.2 (-0.4; 1.3). In the longitudinal analysis, plasma zinc was significantly higher on day 5 (Z-score -3.2 (-4.6; -1.4)) than on day 1 (Z-score -5.2 (-5.2; -3.0), p = 0.032), and plasma magnesium was significantly higher on day 3 (Z-score 1.1 (-0.7; 4.0)) than on day 1 (Z-score -0.3 (-1.6; 0.5), p = 0.018). Plasma copper and selenium remained stable, and the RBC concentrations of all micronutrients remained stable during the first five days. CONCLUSIONS:Most patients had low plasma zinc, copper and selenium concentrations in the first week of their PICU stay, whereas they had normal to high RBC concentrations. More research is needed to examine the relationships between micronutrients and clinical outcome.

In critically ill adults, high plasma cortisol in the face of low ACTH coincides with high pro-opiomelanocortin (POMC) levels. Glucocorticoids further lower ACTH without affecting POMC. We hypothesized that in pediatric cardiac surgery-induced critical illness, plasma POMC is elevated, plasma ACTH transiently rises intraoperatively but becomes suppressed post-operatively, and glucocorticoid administration amplifies this phenotype. From 53 patients (0–36 months), plasma was obtained pre-operatively, intraoperatively, and on post-operative days 1 and 2. Plasma was also collected from 24 healthy children. In patients, POMC was supra-normal pre-operatively (P < 0.0001) but no longer thereafter (P > 0.05). ACTH was never high in patients. While in glucocorticoid-naive patients ACTH became suppressed by post-operative day 1 (P < 0.0001), glucocorticoid-treated patients had already suppressed ACTH intraoperatively (P ≤ 0.0001). Pre-operatively high POMC, not accompanied by increased plasma ACTH, suggests a centrally activated HPA axis with reduced pituitary processing of POMC into ACTH. Increasing systemic glucocorticoid availability with glucocorticoid treatment accelerated the suppression of plasma ACTH. Significance statement Glucocorticoids are often administered during pediatric cardiac surgery. In critically ill children, endogenous systemic glucocorticoid availability is elevated already upon ICU admission while ACTH levels are normal. This hormonal constellation suggests the presence of active feedback inhibition of ACTH. In this study, we have documented that intraoperative administration of glucocorticoids accelerates the suppression of ACTH, resulting in low plasma ACTH already upon ICU admission. Pre-operative plasma POMC, the ACTH precursor, but not ACTH, was increased. This is compatible with a centrally activated HPA axis prior to surgery in young children but reduced processing of POMC into ACTH within the pituitary. These findings suggest that glucocorticoid treatment in the context of pediatric cardiac surgery may amplify pre-existing impaired pituitary processing of the prohormone POMC.

This article tells the story of our long search for the answer to one question: Is stress hyperglycemia in critically ill patients adaptive or maladaptive? Our earlier work had suggested the lack of hepatic insulin effect and hyperglycemia as jointly predicting poor outcome. Therefore, we hypothesized that insulin infusion to reach normoglycemia, tight glucose control, improves outcome. In three randomized controlled trials (RCTs), we found morbidity and mortality benefit with tight glucose control. Moving from the bed to the bench, we attributed benefits to the prevention of glucose toxicity in cells taking up glucose in an insulin-independent, glucose concentration gradient-dependent manner, counteracted rather than synergized by insulin. Several subsequent RCTs did not confirm benefit, and the large Normoglycemia in Intensive Care Evaluation-Survival Using Glucose Algorithm Regulation, or "NICE-SUGAR," trial found increased mortality with tight glucose control associated with severe hypoglycemia. Our subsequent clinical and mechanistic research revealed that early use of parenteral nutrition, the context of our initial RCTs, had been a confounder. Early parenteral nutrition (early-PN) aggravated hyperglycemia, suppressed vital cell damage removal, and hampered recovery. Therefore, in our next and largest "TGC-fast" RCT, we retested our hypothesis, without the use of early-PN and with a computer algorithm for tight glucose control that avoided severe hypoglycemia. In this trial, tight glucose control prevented kidney and liver damage, though with much smaller effect sizes than in our initial RCTs without affecting mortality. Our quest ends with the strong recommendation to omit early-PN for patients in the ICU, as this reduces need of blood glucose control and allows cellular housekeeping systems to play evolutionary selected roles in the recovery process. Once again, less is more in critical care.

The timing, dose, and route of early nutrition support in critically ill patients have been highly controversial for years. Despite the association of a caloric deficit with adverse outcome, several recent large, randomized, controlled trials have demonstrated a prolongation of organ failure and increased muscle weakness with increasing doses of nutrition in the acute phase of critical illness. A potential explanation for the negative impact of early, full feeding on outcome is feeding-induced suppression of autophagy, a cellular repair process that is necessary to clear intracellular damage. Whether nutrition management in critically ill patients should be guided by its effects on autophagy is a topic of debate. Currently, however, autophagy cannot be monitored in clinical practice. Moreover, clinical management should be guided by high-quality randomized controlled trials, which currently do not support the use of early full nutrition support.

Background Former critically ill children show an epigenetic age deceleration 2 years after paediatric intensive care unit (PICU) admission as compared with normally developing healthy children, with stunted growth in height 2 years further in time as physical correlate. This was particularly pronounced in children who were 6 years or older at the time of critical illness. As this age roughly corresponds to the onset of adrenarche and further pubertal development, a relation with altered activation of endocrine pathways is plausible. We hypothesised that children who have been admitted to the PICU, sex- and age-dependently show long-term abnormal DNA methylation within genes involved in steroid hormone synthesis or steroid sulphation/desulphation, possibly aggravated by in-PICU glucocorticoid treatment, which may contribute to stunted growth in height further in time after critical illness. Results In this preplanned secondary analysis of the multicentre PEPaNIC-RCT and its follow-up, we compared the methylation status of genes involved in the biosynthesis of steroid hormones (aldosterone, cortisol and sex hormones) and steroid sulphation/desulphation in buccal mucosa DNA (Infinium HumanMethylation EPIC BeadChip) from former PICU patients at 2-year follow-up ( n = 818) and healthy children with comparable sex and age ( n = 392). Adjusting for technical variation and baseline risk factors and corrected for multiple testing (false discovery rate < 0.05), former PICU patients showed abnormal DNA methylation of 23 CpG sites (within CYP11A1 , POR , CYB5A , HSD17B1 , HSD17B2 , HSD17B3 , HSD17B6 , HSD17B10 , HSD17B12 , CYP19A1 , CYP21A2 , and CYP11B2 ) and 4 DNA regions (within HSD17B2 , HSD17B8 , and HSD17B10 ) that were mostly hypomethylated. These abnormalities were partially sex- (1 CpG site) or age-dependent (7 CpG sites) and affected by glucocorticoid treatment (3 CpG sites). Finally, multivariable linear models identified robust associations of abnormal methylation of steroidogenic genes with shorter height further in time, at 4-year follow-up. Conclusions Children who have been critically ill show abnormal methylation within steroidogenic genes 2 years after PICU admission, which explained part of the stunted growth in height at 4-year follow-up. The abnormalities in DNA methylation may point to a long-term disturbance in the balance between active sex steroids and mineralocorticoids/glucocorticoids after paediatric critical illness, which requires further investigation.

Background Altered DNA-methylation affects biological ageing in adults and developmental processes in children. DNA-methylation is altered by environmental factors, trauma and illnesses. We hypothesised that paediatric critical illness, and the nutritional management in the paediatric intensive care unit (PICU), affects DNA-methylation changes that underly the developmental processes of childhood ageing. Results We studied the impact of critical illness, and of the early use of parenteral nutrition (early-PN) versus late-PN, on “epigenetic age-deviation” in buccal mucosa of 818 former PICU-patients (406 early-PN, 412 late-PN) who participated in the 2-year follow-up of the multicentre PEPaNIC-RCT (ClinicalTrials.gov-NCT01536275), as compared with 392 matched healthy children, and assessed whether this relates to their impaired growth. The epigenetic age-deviation (difference between PedBE clock-estimated epigenetic age and chronological age) was calculated. Using bootstrapped multivariable linear regression models, we assessed the impact hereon of critical illness, and of early-PN versus late-PN. As compared with healthy children, epigenetic age of patients assessed 2 years after PICU-admission deviated negatively from chronological age ( p < 0.05 in 51% of bootstrapped replicates), similarly in early-PN and late-PN groups. Next, we identified vulnerable subgroups for epigenetic age-deviation using interaction analysis. We revealed that DNA-methylation age-deceleration in former PICU-patients was dependent on age at time of illness ( p < 0.05 for 83% of bootstrapped replicates), with vulnerability starting from 6 years onwards. Finally, we assessed whether vulnerability to epigenetic age-deviation could be related to impaired growth from PICU-admission to follow-up at 2 and 4 years. Multivariable repeated measures ANOVA showed that former PICU-patients, as compared with healthy children, grew less in height ( p = 0.0002) and transiently gained weight ( p = 0.0003) over the 4-year time course. Growth in height was more stunted in former PICU-patients aged ≥ 6-years at time of critical illness ( p = 0.002) than in the younger patients. Conclusions As compared with healthy children, former PICU-patients, in particular those aged ≥ 6-years at time of illness, revealed epigenetic age-deceleration, with a physical correlate revealing stunted growth in height. Whether this vulnerability around the age of 6 years for epigenetic age-deceleration and stunted growth years later relates to altered endocrine pathways activated at the time of adrenarche requires further investigation.