Genome-wide expression profiles of necrotizing enterocolitis versus spontaneous intestinal perforation in human intestinal tissues: dysregulation of functional pathways.

OBJECTIVE: To provide a comprehensive database of gene regulation and compare differentially regulated molecular networks in human tissues of necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP). BACKGROUND: Both NEC and SIP are devastating surgical emergencies associated with high morbidity and mortality in preterm infants. Their pathophysiology and molecular mechanisms remain unclear. METHODS: Differential whole genome microarray analysis was performed on intestinal tissues collected from NEC (n = 15) and SIP (n = 12) infants and compared with tissues collected from surgical-control patients with noninflammatory intestinal conditions (n = 14). Validation of 52 target gene expressions was performed by quantitative polymerase chain reaction. Regulatory networks of significantly affected genes were constructed according to functional pathways. RESULTS: Extensive and significant changes of gene expression were observed in NEC tissues, which comprised multiple pathways of angiogenesis, arginine metabolism, cell adhesion and chemotaxis, extracellular matrix remodeling, hypoxia and oxidative stress, inflammation, and muscle contraction. These dysregulated genes could be networked downstream of key receptors, TLR2, TLR4, and TREM1, and mediated via NF-κB, AP-1, and HIF1A transcription factor pathways, indicating predominant microbial and inflammatory involvement. In contrast, SIP tissues exhibited much milder and less diversified expressional changes, with target genes significantly associated with G-protein-mediated muscle contraction and extracellular matrix remodeling. CONCLUSIONS: The molecular evidence suggests that NEC and SIP are likely 2 different diseases caused by distinct etiology and pathophysiology. This first comprehensive database on differential gene expression profiles of human NEC and SIP tissues could lead to development of disease-specific diagnostic and prognostic biomarkers and new therapeutic strategies for improving outcomes.

A Prospective Cohort Study of Fecal miR-223 and miR-451a as Noninvasive and Specific Biomarkers for Diagnosis of Necrotizing Enterocolitis in Preterm Infants.

OBJECTIVE: The objective of this study is to evaluate the usefulness of fecal microRNA (miR)-223 and miR-451a, as novel noninvasive biomarkers for early diagnosis of necrotizing enterocolitis (NEC) in preterm infants. METHODS: Among the top-listed target miRNAs in our previous differential microarray analysis, miR-223 and miR-451a were quantified in a pilot validation case-controlled study (NEC vs. non-NEC/nonsepsis infants; n = 6 in each group). A definitive prospective cohort study (n = 218) further assessed their clinical usefulness as noninvasive and specific diagnostic biomarkers. Fecal calprotectin was quantified in parallel for comparison. RESULTS: Of 43 proven NEC cases in the cohort study, 24 (55.8%) had fecal samples recovered within the first 3 days of clinical presentation. Fecal miRNA-223 (10.5 fold), miR-451a (4.5 fold), and calprotectin (2.1 fold) concentrations were significant higher in NEC compared with the non-NEC group (p < 0.009). Accepting a minimum sensitivity of 0.75, the positive predictive values (PPVs) ranged between 0.19 and 0.20. Combining fecal biomarkers and CRP (Day 1) could marginally increase the PPVs (0.31-0.34) but adversely lowered the sensitivity (0.54-0.63). CONCLUSIONS: Although fecal miRNA biomarkers and calprotectin concentrations were significantly higher in the NEC group, the considerable overlapping of concentrations between groups and low recovery of stool specimens within 72 h of clinical presentation rendered fecal noninvasive tests of limited clinical value in guiding diagnosis of NEC during the acute phase. A further study is underway to evaluate their roles in surveillance for predicting high-risk premature infants developing NEC.

Neonatal Haemophagocytic Lymphohistiocytosis Associated with Maternal Adult-Onset Still's Disease.

Neonatal haemophagocytic lymphohistiocytosis (HLH) is a rare but potentially lethal condition. We recently encountered a preterm infant who developed severe HLH associated with maternal adult-onset Still's disease, which to our knowledge has not been previously reported. The infant presented with fever, generalised lymphadenopathy, transient erythematous skin rash, hepatosplenomegaly, ascites, pancytopenia, marked hyperferritinaemia, and hypofibrinogenaemia, which were features similar to maternal presentation during late pregnancy. Whole gene exome sequencing screening for familial HLH (PRF1, STX11, STXBP2, and MUNC13D genes) was negative. We postulated that factors such as auto-antibodies, antigens, or inflammatory mediators transmitted vertically from the mother could have triggered the intense inflammation in the infant. The infant responded promptly to dexamethasone, etoposide, and cyclosporin A, without the need for bone marrow transplantation. Neonatologists should be alerted to the rare diagnosis of HLH in the presence of active maternal diseases, including infection or autoimmune conditions, especially in association with fever, cytopenia, and hepatosplenomegaly.

Dysregulated expression of arginine metabolic enzymes in human intestinal tissues of necrotizing enterocolitis and response of CaCO2 cells to bacterial components.

The small intestine is the exclusive site of arginine synthesis in neonates. Low levels of circulating arginine have been associated with the occurrence of necrotizing enterocolitis (NEC) but the mechanism of arginine dysregulation has not been fully elucidated. We aimed to investigate (i) expressional changes of arginine synthesizing and catabolic enzymes in human intestinal tissues of NEC, spontaneous intestinal perforation (SIP) and noninflammatory surgical conditions (Surg-CTL) and to investigate the (ii) mechanisms of arginine dysregulation and enterocyte proliferation upon stimulation by bacterial components, arginine depletion, ARG1 overexpression and nitric oxide (NO) supplementation. Our results showed that expressions of arginine synthesizing enzymes ALDH18A1, ASL, ASS1, CPS1, GLS, OAT and PRODH were significantly decreased in NEC compared with Surg-CTL or SIP tissues. Catabolic enzyme ARG1 was increased (>100-fold) in NEC tissues and histologically demonstrated to be expressed by infiltrating neutrophils. No change in arginine metabolic enzymes was observed between SIP and Surg-CTL tissues. In CaCO2 cells, arginine metabolic enzymes were differentially dysregulated by lipopolysaccharide or lipoteichoic acid. Depletion of arginine reduced cell proliferation and this phenomenon could be partially rescued by NO. Overexpression of ARG1 also reduced enterocyte proliferation. We provided the first expressional profile of arginine metabolic enzymes at the tissue level of NEC. Our findings suggested that arginine homeostasis was severely disturbed and could be triggered by inflammatory responses of enterocytes and infiltrating neutrophils as well as bacterial components. Such reactions could reduce arginine and NO, resulting in mucosal damage. The benefit of arginine supplementation for NEC prophylaxis merits further clinical evaluation.

The use of laboratory biomarkers for surveillance, diagnosis and prediction of clinical outcomes in neonatal sepsis and necrotising enterocolitis.

Biomarkers have been used to differentiate systemic neonatal infection and necrotising enterocolitis (NEC) from other non-infective neonatal conditions that share similar clinical features. With increasing understanding in biochemical characteristics of different categories of biomarkers, a specific mediator or a panel of mediators have been used in different aspects of clinical management in neonatal sepsis/NEC. This review focuses on how these biomarkers can be used in real-life clinical settings for daily surveillance, bedside point-of-care testing, early diagnosis and predicting the severity and prognosis of neonatal sepsis/NEC. In addition, with recent development of 'multi-omic' approaches and rapid advancement in knowledge of bioinformatics, more novel biomarkers and unique signatures of mediators would be discovered for diagnosis of specific diseases and organ injuries.

Comparative MiRNA Expressional Profiles and Molecular Networks in Human Small Bowel Tissues of Necrotizing Enterocolitis and Spontaneous Intestinal Perforation.

BACKGROUND: Necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP) are acute intestinal conditions which could result in mortality and severe morbidity in preterm infants. Our objective was to identify dysregulated micro-RNAs (miRNAs) in small bowel tissues of NEC and SIP, and their possible roles in disease pathophysiology. METHODS: We performed differential miRNA arrays on tissues of NEC (n = 4), SIP (n = 4) and surgical-control (Surg-CTL; n = 4), and validated target miRNAs by qPCR (n = 10 each group). The association of target miRNAs with 52 dysregulated mRNAs was investigated by bioinformatics on functional and base-pair sequence algorithms, and correlation in same tissue samples. RESULTS: We presented the first miRNA profiles of NEC, SIP and Surg-CTL intestinal tissues in preterm infants. Of 28 validated miRNAs, 21 were significantly different between NEC or SIP and Surg-CTL. Limited overlapping in the aberrant expression of miRNAs between NEC and SIP indicated their distinct molecular mechanisms. A proposed network of dysregulated miRNA/mRNA pairs in NEC suggested interaction at bacterial receptor TLR4 (miR-31, miR-451, miR-203, miR-4793-3p), mediated via key transcription factors NFKB2 (miR-203), AP-1/FOSL1 (miR-194-3p), FOXA1 (miR-21-3p, miR-431 and miR-1290) and HIF1A (miR-31), and extended downstream to pathways of angiogenesis, arginine metabolism, cell adhesion and chemotaxis, extracellular matrix remodeling, hypoxia/oxidative stress, inflammation and muscle contraction. In contrast, upregulation of miR-451 and miR-223 in SIP suggested modulation of G-protein-mediated muscle contraction. CONCLUSIONS: The robust response of miRNA dysregulation in NEC and SIP, and concerted involvement of specific miRNAs in the molecular networks indicated their crucial roles in mucosa integrity and disease pathophysiology.