Mechanism of Neonatal Intestinal Injury Induced by Hyperoxia Therapy

High concentration oxygen is widely used in the treatment of neonates, which has a significant effect on improving blood oxygen concentration in neonates with respiratory distress. The adverse effects of hyperoxia therapy on the lung, retina, and neurodevelopment of newborns have been extensively studied, but less attention has been paid to intestinal damage caused by hyperoxia therapy. In this review, we focus on the physical, immune, and microorganism barriers of the intestinal tract and discuss neonatal intestinal tract damage caused by hyperoxia therapy and analyze the molecular mechanism of intestinal damage caused by hyperoxia in combination with necrotizing enterocolitis.

Necrotizing Enterocolitis in a Dutch Cohort of Very Preterm Infants: Prevalence, Mortality, and Long-Term Outcomes

Introduction To improve counseling of parents and to guide care strategies, we studied the disease course and outcomes of necrotizing enterocolitis (NEC) up to 2 years of corrected age (CA) from a multidisciplinary perspective. Materials and Methods This was a retrospective cohort study in preterm infants (birth weight < 1,500 g, gestational age < 32 weeks), diagnosed with NEC (Bell's stage ≥ II) from 2008 through 2020. Data on prevalence, mortality, surgery, intestinal failure (IF), growth, and neurodevelopment at 2-year follow-up were separately analyzed for medically and surgically treated children. Results Of 3,456 preterm infants, 200 (6%) were diagnosed with NEC, of whom 135 developed an indication for surgery within 7 days after the diagnosis; 28/135 died before surgery, and 37/107 died after an open-and-close procedure. An enterostomy was constructed in 62 patients and an end-to-end anastomosis in 15. The postoperative course was described for 77 patients, of whom 23 developed surgical complications (12/23 incisional hernias, 9/23 anastomotic strictures), 13/77 a short bowel, and 25/77 IF. Sixty-day survival after birth for medical NEC patients was 88% (hazard ratio [HR]: 0.698; p = 0.318), and for surgically treated NEC patients was 40% (HR: 3.729; p < 0.001). At 2-year follow-up, one patient received parenteral nutrition. Severe delay in weight for age, motor, and cognitive development was seen in 3, 6, and 2%, respectively. Conclusion In this cohort, the mortality rate was high, especially in surgically treated NEC patients. The surgical complication rate is comparable to previous studies, but in surviving patients, persisting IF and severe delay in growth and neurodevelopment at 2 years CA were relatively rare.

Altered microstructure of the splenium of corpus callosum is associated with neurodevelopmental impairment in preterm infants with necrotizing enterocolitis

Background Necrotizing enterocolitis (NEC) is a devastating disease in preterm infants with significant morbidities, including neurodevelopmental impairment (NDI). This study aimed to investigate whether NEC is associated with (1) brain volume expansion and white matter maturation using diffusion tensor imaging analysis and (2) NDI compared with preterm infants without NEC. Methods We included 86 preterm infants (20 with NEC and 66 without NEC) with no evidence of brain abnormalities on trans-fontanelle ultrasonography and magnetic resonance imaging at term-equivalent age (TEA). Regional brain volume analysis and white matter tractography were performed to study brain microstructure alterations. NDI was assessed using the Bayley Scales of Infant and Toddler Development-III (BSID-III) at 18 months of corrected age (CA). Results Preterm infants with NEC showed significantly high risk of motor impairment (odds ratio 58.26, 95% confidence interval 7.80–435.12, p < 0.001). We found significantly increased mean diffusivity (MD) in the splenium of corpus callosum (sCC) (p = 0.001) and the left corticospinal tract (p = 0.001) in preterm infants with NEC. The sCC with increased MD showed a negative association with the BSID-III language (p = 0.025) and motor scores (p = 0.002) at 18 months of CA, implying the relevance of sCC integrity with later NDI. Conclusion The white matter microstructure differed between preterm infants with and without NEC. The prognostic value of network parameters of sCC at TEA may provide better information for the early detection of NDI in preterm infants.

DMBT1 expression and neutrophil-to-lymphocyte ratio during necrotizing enterocolitis are influenced by impaired perfusion due to cardiac anomalies

Background Deleted in malignant brain tumors 1 (DMBT1) is involved in innate immunity and epithelial differentiation. It has been proven to play a role in various states of inflammation or hypoxia of fetal gastrointestinal and pulmonary diseases. Discrimination of pathogenesis in necrotizing enterocolitis (NEC) based on cardiac status improves the understanding of NEC in different patient subgroups. We aimed at examining DMBT1 expressions regarding their association with cardiac status leading to impaired intestinal perfusion, intraoperative bacteria proof, and a fulminant course of NEC. Methods Twenty-eight patients with NEC were treated surgically between 2010 and 2019 at our institution. DMBT1 expression was examined in intestinal sections using immunohistochemistry to detect DMBT1 protein. Associations of clinical parameters and DMBT1 expression were analyzed. Results We examined DMBT1 levels in 10 patients without cardiac defects and 18 patients with persisting ductus arteriosus (PDA) and congenital heart defects (CHD). Compared to patients without cardiac malformations, DMBT1 levels tended to score higher in patients with PDA/CHD (p = 0.2113) and were negatively correlated with C-reactive protein in these infants (p = 0.0172; r = − 0.5533). The number of DMBT1-expressing macrophages was elevated in the PDA/CHD-subgroup (p = 0.0399). Ratios of neutrophils and monocytes to lymphocytes were significantly higher in infants with PDA/CHD (p = 0.0319 and 0.0493). DMBT1 expression was significantly associated with positive bacterial culture of intraoperative swabs (p = 0.0252) and DMBT1 expression of the serosa was associated with a fulminant course of NEC (p = 0.0239). Conclusions This study demonstrates that DMBT1 expression may be influenced by cardiac anomalies with an impaired intestinal perfusion in the neonatal intestine. NEC in PDA/CHD infants is associated with more DMBT1-positive macrophages and a significantly elevated neutrophil-to-lymphocyte ratio.

Expression of OLFM4 and Lysozyme During Necrotizing Enterocolitis and Volvulus in Newborns: a Comparative Observational Research Study

Background: In neonatal patients with necrotizing enterocolitis (NEC) and volvulus the inflammatory response is mediated by a plurality of different proteins. The proteins olfactomedin 4 (OLFM4) and lysozyme (LYZ) are part of the intestinal mucosal defense and especially OLFM4 has rarely been evaluated in neonatal gastrointestinal diseases. The aim of this study was to compare the expression levels of OLFM4 and lysozyme during NEC and volvulus in neonates. Methods: Intestinal tissues of patients with NEC and patients with volvulus were examined using immunohistochemical staining of OLFM4 and lysozyme of formalin-fixed and paraffin-embedded sections of resected tissue. Staining-positive tissues were semi-quantitatively scored from 0 (no staining), 1 (weak staining), 2 (moderate staining) to 3 (highly intense staining) by two individual investigators.Results: Both applied antibodies against OLFM4 showed different staining patterns with higher staining intensity of the antibody OLFM4 (D1E4M). OLFM4 (median score of the antibody OLFM4 (D1E4M): 3.0) and lysozyme (median score: 3.0) are highly expressed in intestinal and immune cells during NEC. The expression of OLFM4 and lysozyme in tissue with intestinal volvulus was also observable (median score of the antibody OLFM4 (D1E4M): 1.25) and median score of the antibody against LYZ: 2.0), but lower levels could be seen in comparison to tissue with NEC (p=0.033 and p=0.037, respectively).Conclusions: Both proteins, OLFM4 and lysozyme, may play a role in the pathogenesis of NEC and volvulus in neonatal patients, but the exact mechanisms of OLFM4 and lysozyme function and their role in immunological responses have not yet been resolved. These observations add new insights as basis for further large-scale population research.

Ontogeny of RORγt+ cells in the intestine of newborns and its role in the development of experimental necrotizing enterocolitis

Background Neonates possess an immature and plastic immune system, which is a major cause of some diseases in newborns. Necrotizing enterocolitis (NEC) is a severe and devastating intestinal disease that typically affects premature infants. However, the development of intestinal immune cells in neonates and their roles in the pathological process of NEC have not been elucidated. Results We examined the ontogeny of intestinal lamina propria lymphocytes in the early life of mice and found a high percentage of RORγt+ cells (containing inflammatory Th17 and ILC3 populations) during the first week of life. Importantly, the proportion of RORγt+ cells of intestinal lamina propria further increased in both NEC mice and patients tissue than the control. Furthermore, the application of GSK805, a specific antagonist of RORγt, inhibited IL-17A release and ameliorated NEC severity. Conclusions Our data reveal the high proportion of RORγt+ cells in newborn mice may directly contribute to the development of NEC.

Predictive factors for the surgical treatment of necrotizing enterocolitis in preterm infants: a single-center retrospective study

Background Necrotizing enterocolitis (NEC) is a gastrointestinal disease that tends to occur in premature infants. Some features may be associated with an increased probability that preterm infants with NEC will require surgical treatment. This study aimed to identify the factors that increased the probability of surgical treatment in infants with NEC. Methods We retrospectively analyzed the data of premature infants with NEC who were hospitalized at The Affiliated Hospital of Qingdao University from April 2011 to April 2021. According to the treatments received, these patients were divided into medical NEC group and surgical NEC group. The perinatal characteristics, clinical manifestations, and laboratory values before the onset of NEC were subjected to univariate and multivariate analyses. Results A total of 623 preterm infants with NEC (> Bell’s stage I) were included in this study, including 350 (56%) who received surgical treatment and 273 (44%) who received conservative medical treatment. Multivariate analysis showed that lower gestational age (P = 0.001, odds ratio (OR) (95% CI) = 0.91[0.86–0.96]), early occurrence of NEC (P = 0.003, OR (95% CI) = 0.86 [0.77–0.95]), hemodynamically significant patent ductus arteriosus (P = 0.003, OR (95% CI) = 7.50 [2.03–28.47]), and low serum bicarbonate (P = 0.043, OR (95% CI) = 0.863 [0.749–0.995]) were associated with an increased probability of surgical treatment in preterm infants with NEC. Conclusions Our findings were applied to identify potential predictors for surgical treatment in preterm infants with NEC, which may facilitate early decisive management.