Patient-derived organoid biobank identifies epigenetic dysregulation of intestinal epithelial MHC-I as a novel mechanism in severe Crohn's Disease.

OBJECTIVE: Epigenetic mechanisms, including DNA methylation (DNAm), have been proposed to play a key role in Crohn's disease (CD) pathogenesis. However, the specific cell types and pathways affected as well as their potential impact on disease phenotype and outcome remain unknown. We set out to investigate the role of intestinal epithelial DNAm in CD pathogenesis. DESIGN: We generated 312 intestinal epithelial organoids (IEOs) from mucosal biopsies of 168 patients with CD (n=72), UC (n=23) and healthy controls (n=73). We performed genome-wide molecular profiling including DNAm, bulk as well as single-cell RNA sequencing. Organoids were subjected to gene editing and the functional consequences of DNAm changes evaluated using an organoid-lymphocyte coculture and a nucleotide-binding oligomerisation domain, leucine-rich repeat and CARD domain containing 5 (NLRC5) dextran sulphate sodium (DSS) colitis knock-out mouse model. RESULTS: We identified highly stable, CD-associated loss of DNAm at major histocompatibility complex (MHC) class 1 loci including NLRC5 and cognate gene upregulation. Single-cell RNA sequencing of primary mucosal tissue and IEOs confirmed the role of NLRC5 as transcriptional transactivator in the intestinal epithelium. Increased mucosal MHC-I and NLRC5 expression in adult and paediatric patients with CD was validated in additional cohorts and the functional role of MHC-I highlighted by demonstrating a relative protection from DSS-mediated mucosal inflammation in NLRC5-deficient mice. MHC-I DNAm in IEOs showed a significant correlation with CD disease phenotype and outcomes. Application of machine learning approaches enabled the development of a disease prognostic epigenetic molecular signature. CONCLUSIONS: Our study has identified epigenetically regulated intestinal epithelial MHC-I as a novel mechanism in CD pathogenesis.

Drawing the abdominal pain: A powerful tool to distinguish between organic and functional abdominal pain.

OBJECTIVES: Abdominal pain (AP) in children imposes a large economic burden on the healthcare system. Currently, there are no reliable diagnostic tools to differentiate between organic and functional disorders. We hypothesized from previous research that the analysis of patients' graphic expression of subjective symptoms as well as their interactional behavior adds new ways to differentiate between functional and organic AP. METHODS: Conversation analyses of physician-patient-encounters and graphical expression of AP-based pain were performed. RESULTS: Twenty-two interactions were recorded and analyzed. Fifteen children were diagnosed with organic AP and seven with functional AP. We found marked differences between children with organic and functional AP. For example, all 15 children with organic AP saw the task of drawing a picture of the pain during the interview as a duty, whereas the seven children with functional AP took this as an opportunity to provide detailed descriptions about the nature of the pain, the circumstances, and how the AP impaired their quality of life. CONCLUSION: Analysis of patients' interaction strategies in response to the painting task provides relevant clues as to whether AP is functional or requires further workup for organic causes.

Precision nutrition in pediatric IBD: A position paper from the ESPGHAN special interest group for basic science and translational research, the IBD Porto group, and allied health professionals.

Stratified and precision nutrition refers to disease management or prevention of disease onset, based on dietary interventions tailored to a person's characteristics, biology, gut microbiome, and environmental exposures. Such treatment models may lead to more effective management of inflammatory bowel disease (IBD) and reduce risk of disease development. This societal position paper aimed to report advances made in stratified and precision nutritional therapy in IBD. Following a structured literature search, limited to human studies, we identified four relevant themes: (a) nutritional epidemiology for risk prediction of IBD development, (b) food-based dietary interventions in IBD, (c) exclusive enteral nutrition (EEN) for Crohn's disease (CD) management, and (d) pre- and probiotics for IBD management. There is scarce literature upon which we can make recommendations for precision or stratified dietary therapy for IBD, both for risk of disease development and disease management. Certain single-nucleotide polymorphisms related to polyunsaturated fatty acid (PUFA) metabolism may modify the effect dietary PUFA have in increasing the risk of IBD development. Non-colonic CD, mild-to-moderate CD, and high microbiota richness may predict success of EEN and may be used both for prediction of treatment continuation, but also for early cessation in nonresponders. There is currently insufficient evidence to make recommendations for precision or stratified dietary therapy for patients with established IBD. Despite the great interest in stratified and precision nutrition, we currently lack data to support conclusive recommendations. Replication of early findings by independent research groups and within structured clinical interventions is required.

Paediatric inflammatory multisystem syndrome - temporally associated with SARS-CoV-2 (PIMS-TS) - a German single centre real-life evaluation of the Swiss and UK consensus statements.

BACKGROUND: In the absence of randomised trials for paediatric multisystem inflammatory syndrome temporally associated with SARS-CoV2 (PIMS-TS), optimal management of PIMS-TS-patients remains somewhat uncertain. We aimed to evaluate the practicability of consensus diagnostic/therapeutic pathways in a real-life German hospital setting. METHODS: All children treated for PIMS-TS (February to November, 2021) at the Childrens' Hospital Kassel were analysed retrospectively. Patients were treated according to local PIMS-TS standardised operating procedure based on the Swiss and UK consensus statements. RESULTS: Eleven patients treated for PIMS-TS were included in this study (female:male = 2.1:1). According to the categories of the Swiss and UK consensus statements, 36% were uncomplicated hyperinflammation, 36% Kawasaki-like and 27% shock-like disease. Local estimated incidence was 0.92/1000 Covid-19 cases in children aged 4-15 years. Significant inter-group differences in laboratory parameters were found: BNP was highest in shock-like presentation compared to Kawasaki-like and uncomplicated hyperinflammation (median 954 (668-1491) versus 213 (173-934) versus 80 (5-257) ng/l, p = 0.02), whereas troponin was highest in Kawasaki-like, followed by shock-like presentation and uncomplicated hyperinflammation (median 34.7 (27.5-58.4) versus 19.1 (14.1-23.4) versus 1.9 (1.9-16.4) ng/l, p = 0.02). Patients with shock-like presentation needed circulatory resuscitation in the paediatric ICU. All patients received standardised operating procedure-based therapy and were discharged home after a medium of 7.4 days. CONCLUSION: The Swiss and UK consensus statements on the management of PIMS-TS proved very valuable in a real-life clinical setting, facilitated early categorisation, and initiation of specific therapy, possibly improving the outcome. Additional randomised trials are necessary to further improve the management of PIMS-TS.

Making Research Flourish Through ESPGHAN: A Position Paper From the ESPGHAN Special Interest Group for Basic and Translational Research.

ABSTRACT: Recent research breakthroughs have emerged from applied basic research throughout all scientific areas, including adult and paediatric gastroenterology, hepatology and nutrition (PGHAN). The research landscape within the European Society of Paediatric Gastroenterology and Nutrition (ESPGHAN) is also inevitably changing from clinical research to studies involving applied laboratory research. This position paper aims to depict the current status quo of basic science and translational research within ESPGHAN, and to delineate how the society could invest in research in the present and future time. The paper also explores which research areas in the field of PGHAN represent the current and future priorities, and what type of support is needed across the ESPGHAN working groups (WGs) and special interest groups (SIGs) to fulfil their research goals.

[Genetic Investigations in Children with Developmental Disorders, Intellectual Disability and/or Epilepsy - The Parents' Perspective]. / Genetische Untersuchungen bei Kindern und Jugendlichen mit Entwicklungsstörung, Behinderung und Epilepsien ­ was erwarten Eltern von der Aufklärung.

BACKGROUND: Shared decision-making is indispensable when it comes to molecular genetic investigations, but data on the expectations of the parents is scarce. METHODS: Using a step-by-step approach we initially performed free in-depth-interviews with five parents on which base we developed a half standardized questionnaire. This questionnaire was then applied in interviews with 30 parents of children with intellectual disability, autism or epilepsy subject to genetic examination. RESULTS: Pre-diagnostic discussions are challenging for the parents in an intellectual as well as emotional way. The most important general aspects are diagnosis and therapy. Self-assessment of prior knowledge is very variable and many parents expressed problems in understanding. During the conversation parents rate the following specific aspects as "very important" or "important": findings of unclear relevance, incidental findings, psychic consequences, prognostic aspects, possible therapeutic interventions. 10 Parents did not have any school-degree and 20 parents were not native speakers. DISCUSSION: All parents express a high need for information covering almost all aspects of the investigation. Communicational hurdles pose additional challenges leaving a large room for improvement. Trustworthy internet-based information systems in different languages including plain language could be a first step.

Oligoclonal bands predict multiple sclerosis in children with optic neuritis.

We retrospectively evaluated predictors of conversion to multiple sclerosis (MS) in 357 children with isolated optic neuritis (ON) as a first demyelinating event who had a median follow-up of 4.0 years. Multiple Cox proportional-hazards regressions revealed abnormal cranial magnet resonance imaging (cMRI; hazard ratio [HR] = 5.94, 95% confidence interval [CI] = 3.39-10.39, p < 0.001), presence of cerebrospinal fluid immunoglobulin G oligoclonal bands (OCB; HR = 3.69, 95% CI = 2.32-5.86, p < 0.001), and age (HR = 1.08 per year of age, 95% CI = 1.02-1.13, p = 0.003) as independent predictors of conversion, whereas sex and laterality (unilateral vs bilateral) had no influence. Combined cMRI and OCB positivity indicated a 26.84-fold higher HR for developing MS compared to double negativity (95% CI = 12.26-58.74, p < 0.001). Accordingly, cerebrospinal fluid analysis may supplement cMRI to determine the risk of MS in children with isolated ON.

A longitudinal, randomized, and prospective study of nocturnal monitoring in children and adolescents with epilepsy: Effects on quality of life and sleep.

OBJECTIVE: Most studies on seizure detection systems focus more on the effectiveness of devices than on their practicability in and impact on everyday life. Our study investigated the impact of a technical monitoring system on subjective quality of sleep and the lives of affected families. Furthermore, we evaluated the impact of anxiety levels on seizure monitoring and vice versa. METHODS: Forty-three patients with newly diagnosed epilepsy were included. Initially, the families decided whether they did (group 1, n=27) or did not (group 2, n=16) want to use a monitoring device. In group 1, patients were randomly assigned to using Epi-Care® (group 1A, n=14) or an audio baby monitor (group 1B, n=13). Quality of life was assessed at two points (t1, at the start of the study and t2, at 5-7months of follow-up) using the SF-12, Kindl-R, and "Familien-Belastungs-Fragebogen" (German version of the "Impact on Family Scale"). In addition, parental anxiety was measured using the State-Trait Anxiety-Inventory, and subjective quality of sleep was measured using the Pittsburgh Sleep Quality Index. Statistical analysis focused on the possible differences between groups 1 and 2 that may influence parents' decisions and the effects of the presence and types of technical monitoring over time. RESULTS: Anxiety levels were not significantly different between the groups with and without monitoring (group 1 vs. group 2). We also found no statistically significant, substantial baseline differences between the Epi-Care® and audio baby monitor groups, with at least medium effect sizes (group 1A vs. group 1B). Parents' health-related mental quality of life measured via the SF-12 increased significantly over time in all groups. By tendency, the fear of further seizures as well as the frequency of cosleeping arrangements in the monitoring group decreased during the study and approached the stable values of the control group. SIGNIFICANCE: Individual parental anxiety levels are not crucial in the decision regarding the use of a monitoring device. A monitoring system may help some families in certain aspects of daily life. During the first months following a diagnosis of epilepsy, quality of life increases independently of the use of a monitoring system.

Epigenetics in Paediatric Gastroenterology, Hepatology, and Nutrition: Present Trends and Future Perspectives.

Epigenetics can be defined as stable, potentially heritable changes in the cellular phenotype caused by mechanisms other than alterations to the underlying DNA sequence. As such, any observed phenotypic changes including organ development, aging, and the occurrence of disease could be driven by epigenetic mechanisms in the presence of stable cellular DNA sequences. Indeed, with the exception of rare mutations, the human genome-sequence has remained remarkably stable over the past centuries. In contrast, substantial changes to our environment as part of our modern life style have not only led to a significant reduction of certain infectious diseases but also seen the exponential increase in complex traits including obesity and multifactorial diseases such as autoimmune disorders. It is becoming increasingly clear that epigenetic mechanisms operate at the interface between the genetic code and our environment, and a large body of existing evidence supports the importance of environmental factors such as diet and nutrition, infections, and exposure to toxins on human health. This seems to be particularly the case during vulnerable periods of human development such as pregnancy and early life. Importantly, as the first point of contact for many of such environmental factors including nutrition, the digestive system is being increasingly linked to a number of "modern" pathologies. In this review article, we aim to give a brief introduction to the basic molecular principals of epigenetics and provide a concise summary of the existing evidence for the role of epigenetic mechanisms in gastrointestinal health and disease, hepatology, and nutrition.

The influence of real-time blood glucose levels on left ventricular myocardial strain and strain rate in pediatric patients with type 1 diabetes mellitus - a speckle tracking echocardiography study.

BACKGROUND: Echocardiographic myocardial performance parameters such as strain and strain rate are increasingly used to assess systolic and diastolic function in patients with diabetes mellitus and several other clinical and scientific scenarios. While long-term metabolic marks such as HbA1C are inherently assessed in diabetic patients, the actual blood glucose level at the very moment of the echocardiographic study has not yet been taken into account for the assessment of cardiac mechanics. The aim of this study was to investigate the influence of real-time blood glucose levels on left ventricular (LV) myocardial strain and strain rate in pediatric patients with type 1 diabetes mellitus (T1DM). METHODS: We performed speckle tracking echocardiography on 39 normotensive pediatric patients with uncomplicated type 1 diabetes mellitus (mean age 11.5 ± 3.5 years, 40 % female) and 44 sex- and age-matched healthy controls (mean age 11.4 ± 2.9 years, 45 % female). T1DM patients were sub-categorized according to their blood sugar levels (with a cutoff of 150 mg/dL) at the moment of the echocardiographic exam. Investigators were blinded to the participants' study group status. RESULTS: Interestingly, diabetic patients with higher blood sugar levels demonstrated significantly increased LV circumferential strain (p = 0.003) and strain rate (p = 0.005) as well as global longitudinal strain rate (p = 0.002) in comparison to T1DM patients with lower blood sugar levels or healthy controls. CONCLUSIONS: For the investigation of myocardial performance with sensitive methods such as speckle tracking echocardiography in diabetic study populations real-time blood sugar levels should be taken into account. Further studies are needed to verify these findings in large-scale patient cohorts and serial intra-individual measurements in different metabolic states.

Operative management of cryptorchidism: guidelines and reality--a 10-year observational analysis of 3587 cases.

BACKGROUND: Undescended testis (UDT) is the most common disorder in pediatric surgery and one of the most important risk factors for malignancy and subfertility. In 2009 local guidelines were modified and now recommend treatment to be completed by the age of 1. Aim of this study was to analyze age distribution at the time of orchidopexy, whether the procedure is performed according to guideline recommendations and to assess primary care pediatricians' attitude regarding their treatment approach. METHODS: We retrospectively analyzed 3587 patients with UDT regarding age at orchidopexy between 2003 and 2012 in 13 German hospitals. Furthermore, we conducted an anonymized nation-wide survey among primary care pediatricians regarding their attitude toward management of UDT. RESULTS: Before modification of the guideline 78% (n = 1245) of the boys with UDT were not operated according to guideline recommendations. After the modification that number rose to 95% (n = 1472). 42% of the orchidopexies were performed on patients aged 4 to 17 years. 46% of the primary care pediatricians were not aware of this discrepancy and 38% would only initiate operative management after the first year of life. In hospitals with pediatric surgery departments significantly more patients received orchidopexy in their first year of life (p < .001). CONCLUSION: The guideline for UDT in Germany has not yet been implemented sufficiently. Timing of orchidopexy must be optimized in order to improve long-term prognosis. Both primary care providers and parents should be educated regarding the advantages of early orchidopexy in UDT. Prospective studies are needed to elucidate the high rate of late orchidopexies.

Excessive sodium supplementation but not fluid load is correlated with overall morbidity in extremely low birth weight infants.

Objectives: Sodium homeostasis in extremely low birth weight (ELBW) infants is critical. While a lack of sodium delays growth, excessive supplementation increases morbidity. Methods: We performed a single-center retrospective study on sodium and fluid management during the first 2 weeks of live including all ELBW infants born between June 1, 2017 and May 31, 2019. Results: Forty-seven patients (median GA 26 + 6 weeks, median BW 845 g) were included. Mean sodium intake was above the ESPGHAN recommendation, 4.58 mmol/kg/day during the first 2 days and 1.99 mmol/kg/day during the following period. Incidence of PDA, IVH, and ROP was directly associated with sodium intake (OR 1.6, 1.3, and 1.4, respectively), but not with fluid supplementation. No association to BPD was found. The most important source for inadvertent sodium intake were 0.9% saline given by arterial lines. Sodium supplementation did not correlate directly with serum sodium levels, but a linear regression model combining sodium intake and fluid supplementation was able to predict serum sodium changes 24-48 h in advance (correlation coefficient of 0.294, p < 0.05). Conclusions: Sodium application substantially exceeded ESPGHAN recommendations in ELBW infants. An excess in sodium was associated with an overall increased morbidity, justifying increased efforts to identify inadvertent sodium sources in these patients with the aim to decrease sodium excess.

Fecal S100A12: identifying intestinal distress in very-low-birth-weight infants.

OBJECTIVES: The aim of the study was to determine whether longitudinal measurements of fecal S100A12, a damage-associated molecular pattern protein, which is released from neutrophils or monocytes under stress, can detect very-low-birth-weight (VLBW) infants at risk for intestinal distress apart from necrotizing enterocolitis. METHODS: This prospective study included 46 VLBW infants with intestinal distress and 49 reference patients. Meconium and stool samples were collected prospectively on alternate days for 4 weeks, and fecal S100A12 was measured by enzyme-linked immunosorbent assay. RESULTS: Gestational age and weight at birth were significantly lower in patients with intestinal distress when compared to unaffected reference infants. Median levels of fecal S100A12 were significantly higher in patients with intestinal distress at onset of disease and before compared with unaffected reference infants. Median levels of fecal S100A12 declined steadily to baseline levels within 2 weeks after disease onset. The ideal cutoff value for identifying patients with intestinal distress within 7 days before disease onset was 60 µg/kg (sensitivity 0.73; specificity 0.55). CONCLUSIONS: Fecal S100A12 levels are increased in VLBW infants with intestinal distress; however, the potential for S100A12 as an early biomarker is largely limited by overlaps between values of infants with intestinal distress and the reference population.

Hepatitis B virus genotype change in children is closely related to HBeAg/anti-HBe seroconversion.

BACKGROUND AND OBJECTIVES: Genotype changes have been observed during long-term follow-up in adults with chronic hepatitis B virus (HBV) infection. The aim of this study was to assess the frequency and distribution of HBV genotype shifts in treated and untreated European children during the different phases of chronic hepatitis B. METHODS: The initial population consisted of 85 HBeAg-positive children who were sequentially investigated for HBV genotypes for a mean period of 7.1 years. During the survey, 65 patients seroconverted to anti-HBe and 24 received antiviral treatment. Genotyping was done by restriction fragment length polymorphism. RESULTS: Genotypes at enrollment were distributed as follows: D (n = 67), A (n = 11), B (n = 4), and C and mixed (n = 3). A genotype change was observed in 16 (19%) participants at last visit, of whom 1 of 20 (5%) remained persistently HBeAg positive and 15 of 65 (23%) children had seroconverted to anti-HBe (P < 0.001). The genotype shift was D to A or B in 9 individuals, A to D in 5, and A to B in 1. Genotype changes were more frequent in untreated than in treated subjects; however, the difference was not statistically significant. CONCLUSIONS: The results of this study suggest that genotype change is a relatively frequent event in children with chronic hepatitis B after anti-HBe seroconversion and independent of treatment. The reasons why only some patients will experience this event remain to be clarified.

Uncovering the gastrointestinal passage, intestinal epithelial cellular uptake, and AGO2 loading of milk miRNAs in neonates using xenomiRs as tracers.

BACKGROUND: Human breast milk has a high microRNA (miRNA) content. It remains unknown whether and how milk miRNAs might affect intestinal gene regulation and homeostasis of the developing microbiome after initiating enteral nutrition. However, this requires that relevant milk miRNA amounts survive the gastrointestinal (GI) passage, are taken up by cells, and become available to the RNA interference machinery. It seems important to dissect the fate of these miRNAs after oral ingestion and GI passage. OBJECTIVES: Our goal was to analyze the potential transmissibility of milk miRNAs via the gastrointestinal system in neonate humans and a porcine model in vivo to contribute to the discussion of whether milk miRNAs could influence gene regulation in neonates and thus might vertically transmit developmental relevant signals. METHODS: We performed cross-species profiling of miRNAs via deep sequencing and utilized dietary xenobiotic taxon-specific milk miRNA (xenomiRs) as tracers in human and porcine neonates, followed by functional studies in primary human fetal intestinal epithelial cells using adenovirus-type 5-mediated miRNA gene transfer. RESULTS: Mammals share many milk miRNAs yet exhibit taxon-specific miRNA fingerprints. We traced bovine-specific miRNAs from formula nutrition in human preterm stool and 9 d after the onset of enteral feeding in intestinal cells (ICs) of preterm piglets. Thereafter, several xenomiRs accumulated in the ICs. Moreover, a few hours after introducing enteral feeding in preterm piglets with supplemented reporter miRNAs (cel-miR-39-5p/-3p), we observed their enrichment in blood serum and in argonaute RISC catalytic component 2 (AGO2)-immunocomplexes from intestinal biopsies. CONCLUSIONS: Milk-derived miRNAs survived GI passage in human and porcine neonates. Bovine-specific miRNAs accumulated in ICs of preterm piglets after enteral feeding with bovine colostrum/formula. In piglets, colostrum supplementation with cel-miR-39-5p/-3p resulted in increased blood concentrations of cel-miR-39-3p and argonaute RISC catalytic component 2 (AGO2) loading in ICs. This suggests the possibility of vertical transmission of miRNA signaling from milk through the neonatal digestive tract.

H3.5 is a novel hominid-specific histone H3 variant that is specifically expressed in the seminiferous tubules of human testes.

The incorporation of histone variants into chromatin plays an important role for the establishment of particular chromatin states. Six human histone H3 variants are known to date, not counting CenH3 variants: H3.1, H3.2, H3.3 and the testis-specific H3.1t as well as the recently described variants H3.X and H3.Y. We report the discovery of H3.5, a novel non-CenH3 histone H3 variant. H3.5 is encoded on human chromosome 12p11.21 and probably evolved in a common ancestor of all recent great apes (Hominidae) as a consequence of H3F3B gene duplication by retrotransposition. H3.5 mRNA is specifically expressed in seminiferous tubules of human testis. Interestingly, H3.5 has two exact copies of ARKST motifs adjacent to lysine-9 or lysine-27, and lysine-79 is replaced by asparagine. In the Hek293 cell line, ectopically expressed H3.5 is assembled into chromatin and targeted by PTM. H3.5 preferentially colocalizes with euchromatin, and it is associated with actively transcribed genes and can replace an essential function of RNAi-depleted H3.3 in cell growth.

Fecal phagocyte-specific S100A12 for diagnosing necrotizing enterocolitis.

OBJECTIVE: To determine whether longitudinal measurements of fecal S100A12, a fecal marker of intestinal inflammation, can identify very low birth weight infants at risk for necrotizing enterocolitis (NEC). STUDY DESIGN: This prospective study included 145 preterm infants with birth weight <1500 g. Meconium and stool samples (n = 843) were collected prospectively on alternate days for 4 weeks, and fecal S100A12 and calprotectin were measured by enzyme-linked immunosorbent assay. RESULTS: Eighteen patients (12.4%) developed NEC. Gestational age and birth weight were significantly lower in the patients with NEC compared with unaffected reference infants. Fecal S100A12 levels were significantly higher in patients with severe NEC at onset of disease and also, in contrast to fecal calprotectin, at 4-10 days before onset of NEC compared with unaffected reference infants (ideal cutoff value, 65 µg/kg; sensitivity, 0.76; specificity, 0.56). CONCLUSIONS: Fecal S100A12 level may be a helpful marker for predicting disease severity and early risk assessment for subsequent development of NEC. However, the use of fecal S100A12 as a predictive biomarker for NEC in very low birth weight infants may be limited due to a high interindividual and intraindividual variability in S100A12 fecal excretion.

Epigenetics in inflammatory bowel disease.

PURPOSE OF REVIEW: To briefly summarize some of the principles of epigenetics and assess their potential relevance for the disease pathogenesis of inflammatory bowel diseases (IBDs). To review the results of recent IBD-related epigenetic studies, discuss main challenges as well as highlight the opportunities for future research in this field. RECENT FINDINGS: Evidence is accumulating for a major role of epigenetic mechanisms in the disease pathogenesis of several immune-mediated diseases. Recent findings indicate that epigenetics may mediate some of the effects of environment, genetic predisposition and intestinal microbiota on IBD pathogenesis. SUMMARY: Epigenetics is a rapidly expanding and hugely promising area of research. At best, it may provide a unifying molecular mechanism to explain complex immune-mediated diseases such as IBD. Future research studies must be carefully designed, performed and analysed taking into account the basic principles of epigenetics in order to ensure the true potential of this field is realized in the understanding of IBD.

Human ß-defensin 2 expression in ELBW infants with severe necrotizing enterocolitis.

BACKGROUND: The aim of this study was to analyze whether the mucosal innate immune response of extremely-low-birth-weight (ELBW) infants might play a role in the development of necrotizing enterocolitis (NEC). METHODS: Between April 2008 and December 2009 antimicrobial peptides were prospectively measured in fecal samples of ELBW infants. In cases requiring abdominal surgery, full-thickness gut biopsies were analyzed for expression of human ß-defensin 2 (hBD2), interleukin-8 (IL-8), villin, MD2, and Toll-like receptor 4 (TLR4). RESULTS: Fecal hBD1 concentrations were consistently low in all patients, whereas hBD2 concentrations were high in meconium, particularly in clinical chorioamnionitis, and then dropped, followed by a steady increase after day 14. Infants with moderate NEC showed significantly increased fecal hBD2 concentrations before clinical symptoms, in contrast to infants developing severe NEC. Analysis of intestinal resection material obtained from patients with severe NEC revealed low hBD2 mRNA and protein levels, and increased expression of the inflammatory cytokine IL-8. CONCLUSION: High hBD2 concentrations, reflecting strong intestinal immune responses, were associated with moderate courses of the disease. In severe NEC, low hBD2 expression was accompanied by low TLR4/MD2 expression, suggesting an inadequate response to luminal bacteria, possibly predisposing those infants to the development of NEC.