Assessment of aberrant DNA methylation two years after paediatric critical illness:a pre-planned secondary analysis of the international PEPaNIC trial

Critically ill children requiring intensive care suffer from impaired physical/neurocognitive development 2 y later, partially preventable by omitting early use of parenteral nutrition (early-PN) in the paediatric intensive-care-unit (PICU). Altered methylation of DNA from peripheral blood during PICU-stay provided a molecular basis hereof. Whether DNA-methylation of former PICU patients, assessed 2 y after critical illness, is different from that of healthy children remained unknown. In a pre-planned secondary analysis of the PEPaNIC-RCT (clinicaltrials.gov-NCT01536275) 2-year follow-up, we assessed buccal-mucosal DNA-methylation (Infinium-HumanMethylation-EPIC-BeadChip) of former PICU-patients (N = 406 early-PN; N = 414 late-PN) and matched healthy children (N = 392). CpG-sites differentially methylated between groups were identified with multivariable linear regression and differentially methylated DNA-regions via clustering of differentially methylated CpG-sites using kernel-estimates. Analyses were adjusted for technical variation and baseline risk factors, and corrected for multiple testing (false-discovery-rate <0.05). Differentially methylated genes were functionally annotated (KEGG-pathway database), and allocated to three classes depending on involvement in physical/neurocognitive development, critical illness and intensive medical care, or pre-PICU-admission disorders. As compared with matched healthy children, former PICU-patients showed significantly different DNA-methylation at 4047 CpG-sites (2186 genes) and 494 DNA-regions (468 genes), with most CpG-sites being hypomethylated (90.3%) and with an average absolute 2% effect-size, irrespective of timing of PN initiation. Of the differentially methylated KEGG-pathways, 41.2% were related to physical/neurocognitive development, 32.8% to critical illness and intensive medical care and 26.0% to pre-PICU-admission disorders. Two years after critical illness in children, buccal-mucosal DNA showed abnormal methylation of CpG-sites and DNA-regions located in pathways known to be important for physical/neurocognitive development

Pro-opiomelanocortin and ACTH–cortisol dissociation during pediatric cardiac surgery

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 &lt; 0.0001) but no longer thereafter (P &gt; 0.05). ACTH was never high in patients. While in glucocorticoid-naive patients ACTH became suppressed by post-operative day 1 (P &lt; 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.</p

Pro-opiomelanocortin and ACTH–cortisol dissociation during pediatric cardiac surgery

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 &lt; 0.0001) but no longer thereafter (P &gt; 0.05). ACTH was never high in patients. While in glucocorticoid-naive patients ACTH became suppressed by post-operative day 1 (P &lt; 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.</p

The association of hypoglycemia with outcome of critically ill children in relation to nutritional and blood glucose control strategies

Abstract Background Withholding parenteral nutrition (PN) until one week after PICU admission facilitated recovery from critical illness and protected against emotional and behavioral problems 4 years later. However, the intervention increased the risk of hypoglycemia, which may have counteracted part of the benefit. Previously, hypoglycemia occurring under tight glucose control in critically ill children receiving early PN did not associate with long-term harm. We investigated whether hypoglycemia in PICU differentially associates with outcome in the context of withholding early PN, and whether any potential association with outcome may depend on the applied glucose control protocol. Methods In this secondary analysis of the multicenter PEPaNIC RCT, we studied whether hypoglycemia in PICU associated with mortality (N = 1440) and 4-years neurodevelopmental outcome (N = 674) through univariable comparison and multivariable regression analyses adjusting for potential confounders. In patients with available blood samples (N = 556), multivariable models were additionally adjusted for baseline serum NSE and S100B concentrations as biomarkers of neuronal, respectively, astrocytic damage. To study whether an association of hypoglycemia with outcome may be affected by the nutritional strategy or center-specific glucose control protocol, we further adjusted the models for the interaction between hypoglycemia and the randomized nutritional strategy, respectively, treatment center. In sensitivity analyses, we studied whether any association with outcome was different in patients with iatrogenic or spontaneous/recurrent hypoglycemia. Results Hypoglycemia univariably associated with higher mortality in PICU, at 90 days and 4 years after randomization, but not when adjusted for risk factors. After 4 years, critically ill children with hypoglycemia scored significantly worse for certain parent/caregiver-reported executive functions (working memory, planning and organization, metacognition) than patients without hypoglycemia, also when adjusted for risk factors including baseline NSE and S100B. Further adjustment for the interaction of hypoglycemia with the randomized intervention or treatment center revealed a potential interaction, whereby tight glucose control and withholding early PN may be protective. Impaired executive functions were most pronounced in patients with spontaneous or recurrent hypoglycemia. Conclusion Critically ill children exposed to hypoglycemia in PICU were at higher risk of impaired executive functions after 4 years, especially in cases of spontaneous/recurrent hypoglycemia

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

Time course of altered DNA methylation evoked by critical illness and by early administration of parenteral nutrition in the paediatric ICU

Background: A genome-wide study identifed de novo DNA methylation alterations in leukocytes of children at paediatric intensive care unit (PICU) discharge, ofering a biological basis for their impaired long-term development. Early parenteral nutrition (early-PN) in PICU, compared with omitting PN in the frst week (late-PN), explained diferential methylation of 23% of the afected CpG-sites. We documented the time course of altered DNA methylation in PICU and the impact hereon of early nutritional management. Results: We selected 36 early-PN and 36 late-PN matched patients, and 42 matched healthy children. We quantifed DNA methylation on days 3, 5 and 7 for the 147 CpG-sites of which methylation was normal upon PICU admission in this subset and altered by critical illness at PICU discharge. Methylation in patients difered from healthy children for 64.6% of the 147 CpG-sites on day 3, for 72.8% on day 5 and for 90.5% on day 7 as revealed by ANOVA at each time point. Within-patients methylation time course analyses for each CpG-site identifed diferent patterns based on paired t test p value and direction of change. Rapid demethylation from admission to day 3 occurred for 76.2% of the CpG-sites, of which 67.9% remained equally demethylated or partially remethylated and 32.1% further demethylated beyond day 3. From admission to day 3, 19.7% of the CpG-sites became hypermethylated, of which, beyond day 3, 34.5% remained equally hypermethylated or partially demethylated again and 65.5% further hypermethylated. For 4.1% of the CpG-sites, changes only appeared beyond day 3. Finally, for the CpG-sites afected by early-PN on the last PICU day, earlier changes in DNA methylation were compared for early-PN and late-PN patients, revealing that 38.9% were already diferentially methylated by day 3, another 25.0% by day 5 and another 13.9% by day 7. Conclusions: Critical illness- and early-PN-induced changes in DNA methylation occurred mainly within 3 days. Most abnormalities were at least partially maintained or got worse with longer time in PICU. Interventions targeting aberrant DNA methylation changes should be initiated earl

Dynamics and prognostic value of the hypothalamus–pituitary–adrenal axis responses to pediatric critical illness and association with corticosteroid treatment: a prospective observational study

Purpose: Increased systemic cortisol availability during adult critical illness is determined by reduced binding-proteins and suppressed breakdown rather than elevated ACTH. Dynamics, drivers and prognostic value of hypercortisolism during pediatric critical illness remain scarcely investigated. Methods: This preplanned secondary analysis of the PEPaNIC-RCT (N = 1440), after excluding 420 children treated with corticosteroids before PICU-admission, documented (a) plasma ACTH, (free)cortisol and cortisol-metabolism at PICU-admission, day-3 and last PICU-day, their prognostic value, and impact of withholding early parenteral nutrition (PN), (b) the association between corticosteroid-treatment and these hormones, and (c) the association between corticosteroid-treatment and outcome. Results: ACTH was normal upon PICU-admission and low thereafte

Modulation of bone morphogenetic protein signaling inhibits the onset and progression of ankylosing enthesitis

Joint ankylosis is a major cause of disability in the human spondyloarthropathies. Here we report that this process partially recapitulates embryonic endochondral bone formation in a spontaneous model of arthritis in DBA/1 mice. Bone morphogenetic protein (BMP) signaling appears to be a key molecular pathway involved in this pathological cascade. Systemic gene transfer of noggin, a BMP antagonist, is effective both as a preventive and a therapeutic strategy in the mouse model, mechanistically interfering with enthesial progenitor cell proliferation in early stages of the disease process. Immunohistochemical staining for phosphorylated smad1/5 in enthesial biopsies of patients with spondyloarthropathy reveals active BMP signaling in similar target cells. Our data suggest that BMP signaling is an attractive therapeutic target for interfering with structural changes in spondyloarthropathy either as an alternative or complementary approach to current antiinflammatory treatments.status: publishe

Soluble RAGE and the RAGE ligands HMGB1 and S100A12 in critical illness: impact of glycemic control with insulin and relation with clinical outcome

Systemic inflammation often leads to complications in critically ill patients. Activation of the receptor for advanced glycation end-products (RAGE) generates inflammatory cytokines, proteases, and oxidative stress and may link inflammation to subsequent organ damage. Furthermore, hyperglycemia-induced oxidative stress increases RAGE ligands and RAGE expression. We hypothesized that preventing hyperglycemia during critical illness reduces the risk of excessively enhanced RAGE signaling, which could relate to clinical outcomes and risk of death. In 405 long-stay surgical intensive care unit patients randomized to intensive or conventional insulin treatment, serum concentrations of soluble RAGE (decoy receptor) and the RAGE ligands high-mobility group box 1 (HMGB1) and S100A12 were measured on admission, day 7, and last day. These were compared with levels in 71 matched control subjects and with C-reactive protein (CRP) as a routinely monitored inflammation marker. On admission, soluble RAGE, HMGB1, S100A12, and CRP were higher in patients than in controls. The HMGB1, S100A12, and CRP remained elevated throughout intensive care unit stay, whereas soluble RAGE decreased to levels lower than in controls by day 7. Unexpectedly, insulin treatment did not affect the circulating levels of these markers. In univariable analysis, elevated levels of soluble RAGE on admission were associated with adverse outcome, including circulatory failure, kidney failure, liver dysfunction, and mortality. The associations with circulatory and kidney failure remained significant in multivariable logistic regression analysis corrected for baseline risk factors. Critical illness affects components of RAGE signaling, unaffected by insulin treatment. Elevated on-admission soluble RAGE was associated with adverse outcomes.status: publishe

FGF21 response to critical illness: effect of blood glucose control and relation with cellular stress and survival

CONTEXT: Critical illness is hallmarked by mitochondrial damage, which is attenuated by targeting normoglycemia. Mitochondrial dysfunction induces fibroblast growth factor-21 (FGF21) via the integrated stress response (ISR). OBJECTIVE: We evaluated whether critical illness elevates serum FGF21 concentrations and whether targeting normoglycemia (80-110 mg/dL) with insulin vs tolerating hyperglycemia may lower serum FGF21 by attenuating mitochondrial dysfunction and the ISR. SETTING/DESIGN: We quantified serum FGF21 concentrations in critically ill patients. To allow tissue analyses, including hepatic fgf21 expression in relation with mitochondrial function and ISR markers, we studied critically ill rabbits. Patients and rabbits were randomized to hyper- or normoglycemia. Patients/Other Participants: We studied 405 fed critically ill patients vs 20 matched non-critically ill control subjects as well as 26 critically ill rabbits vs 13 healthy rabbits. INTERVENTIONS: Insulin was infused to control blood glucose. MAIN OUTCOME MEASURES AND RESULTS: Serum FGF21 concentrations upon intensive care unit admission were 8-fold higher than in control subjects (P < .0001), decreased with time, but always remained higher in nonsurvivors than survivors (P ≤ .006). Maintaining normoglycemia lowered serum FGF21 (P = .01), statistically explaining at least part of its mortality benefit. In ill rabbits, hepatic fgf21 expression was substantially increased (P < .0001) and was tightly correlated with mitochondrial dysfunction (all R(2) ≥ 0.49; all P ≤ .0006 for complex I and V) and ISR markers on day 3 (R(2) ≥ 0.73; P ≤ .0001), all lowered by targeting normoglycemia. CONCLUSION: Critical illness is a potent inducer of serum FGF21 and of liver fgf21 expression, possibly driven at least in part by mitochondrial damage and the ISR, which were all attenuated by targeting normoglycemia.status: publishe