Intestinal microcirculation and necrotizing enterocolitis: The vascular endothelial growth factor system

[Research progress on the relationship between anemia and neonatal necrotizing enterocolitis]

Neonatal necrotizing enterocolitis (NEC) is the most common inflammatory intestinal disease in preterm infants, with a high incidence and mortality rate. The etiology and mechanisms of NEC are not yet fully understood, and multiple factors contribute to its occurrence and development. Recent studies have found that anemia is a risk factor for NEC in neonates, but the specific pathogenic mechanism remains unclear. This article reviews recent research on the relationship between anemia and NEC, providing a reference for further understanding the impact of anemia on intestinal injury and its association with NEC.

Delayed episode of necrotising enterocolitis in an ex-preterm infant after intravitreal administration of low-dose ranibizumab for the treatment of retinopathy of prematurity

Retinopathy of prematurity (ROP) and necrotising enterocolitis (NEC) are complications of prematurity. Despite being quite different in terms of incidence, pathogenesis and consequences, both share a pathogenic role of aberrant vascularisation: increased in ROP, deficient for NEC. Current therapy for ROP includes the use of anti-vascular endothelial growth factor (anti-VEGF) agents, which are able to interrupt retinal hypervascularity. Despite being delivered intravitreously, anti-VEGF used in ROP can be absorbed into circulation and exert systemic effects. We present here a case of an ex-27 weeks gestational age infant, presenting multiple NEC risk factors, treated at 2 months of age with low-dose ranibizumab, who developed a large bowel NEC episode in the first week after treatment. We believe that this further report of an association between anti-VEGF agents and NEC could be interesting for the identification of children at risk of severe adverse events and stimulating further research on the topic.

Recombinant IGF-1/BP3 protects against intestinal injury in a neonatal mouse NEC model

BACKGROUND

Recombinant human IGF-1/binding protein-3 (rhIGF-1/BP3) is currently being tested in phase II clinical trials in premature infants to prevent bronchopulmonary dysplasia, but its impact on the neonatal intestine remains unclear. The aim of this study was to determine whether rhIGF-1/BP3 protects against necrotizing enterocolitis (NEC) in mice and to investigate the mechanisms involved.

METHODS

Neonatal mice were dam fed or injected intraperitoneally with rhIGF-1/BP3 (or vehicle) and submitted to an experimental NEC model. Serum IGF-1 was assessed by ELISA and intestinal vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) expression by Western blot. Intestinal endothelial cell proliferation, and enterocyte proliferation and migration were examined by immunofluorescence. Pup survival and histological intestinal injury were determined.

RESULTS

In pups exposed to experimental NEC, serum IBP3-bound IGF-1 level was decreased. Exogenous rhIGF-1/BP3 preserved VEGF and VEGFR2 protein expression, decreased vascular permeability, and preserved endothelial cell proliferation in the small intestine. Furthermore, rhIGF-1/BP3 promoted enterocyte proliferation and migration, which effects were attenuated by inhibiting VEGFR2 signaling, decreased enterocyte apoptosis and decreased systemic and intestinal inflammation. rhIGF-1/BP3 improved survival and reduced the incidence of severe intestinal injury in experimental NEC.

CONCLUSIONS

Exogenous rhIGF-1/BP3 protects neonatal mice against experimental NEC via multiple mechanisms.

IMPACT

Exogenous rhIGF-1/BP3 preserves intestinal microvascular development and integrity, promotes enterocyte proliferation and migration, decreases local and systemic inflammation, and protects neonatal mice against NEC. The article adds pre-clinical evidence of a protective role for rhIGF-1/BP3 on the premature gut. It provides evidence supporting the use of rhIGF1/BP3 in premature neonates to protect against NEC.

Photoacoustic Imaging as a Novel Non-invasive Biomarker to Assess Intestinal Tissue Oxygenation and Motility in Neonatal Rats

BACKGROUND

Within the premature infant intestine, oxygenation and motility play key physiological roles in healthy development and disease such as necrotizing enterocolitis. To date, there are limited techniques to reliably assess these physiological functions that are also clinically feasible for critically ill infants. To address this clinical need, we hypothesized that photoacoustic imaging (PAI) can provide non-invasive assessment of intestinal tissue oxygenation and motility to characterize intestinal physiology and health.

METHODS

Ultrasound and photoacoustic images were acquired in 2-day and 4-day old neonatal rats. For PAI assessment of intestinal tissue oxygenation, an inspired gas challenge was performed using hypoxic, normoxic, and hyperoxic inspired oxygen (FiO2). For intestinal motility, oral administration of ICG contrast agent was used to compare control animals to an experimental model of loperamide-induced intestinal motility inhibition.

RESULTS

PAI demonstrated progressive increases in oxygen saturation (sO2) as FiO2 increased, while the pattern of oxygen localization remained relatively consistent in both 2-day and 4-day old neonatal rats. Analysis of intraluminal ICG contrast enhanced PAI images yielded a map of the motility index in control and loperamide treated rats. From PAI analysis, loperamide significantly inhibited intestinal motility, with a 32.6% decrease in intestinal motility index scores in 4-day old rats.

CONCLUSION

These data establish the feasibility and application of PAI to non-invasively and quantitatively measure intestinal tissue oxygenation and motility. This proof-of-concept study is an important first step in developing and optimizing photoacoustic imaging to provide valuable insight into intestinal health and disease to improve the care of premature infants.

Genetic susceptibility for retinopathy of prematurity and its associated comorbidities

BACKGROUND

Retinopathy of prematurity (ROP) is one of the leading cause of child blindness. Preterm newborns of very low gestational age (GA) and very low birth weight are at the greatest risk. Our objective was to evaluate the role of genetic variants associated with ROP risk and its comorbidities in an Argentinian sample of premature infants.

METHODS

A sample of 437 preterm infants <33 weeks GA, born at a maternity hospital in Tucumán, Argentina, 2005-2010, was analyzed. Environmental factors, perinatal outcomes, and fourteen single nucleotide polymorphisms associated with ROP were evaluated, comparing ROP with non-ROP newborns. A lasso logistic regression was performed to select variables; then, a conditional logistic regression was used to identify ROP maternal and perinatal risk factors adjusting by maternal and gestational ages, respectively.

RESULTS

ROP maternal risk factors were alcohol intake, periodontal infections, and severe stress. Respiratory distress, sepsis, and intracranial hemorrhage were the ROP perinatal risk factors. Markers rs186085 of EPAS1 and rs427832 of AGTR1 were significantly associated with ROP newborns.

CONCLUSION

We identified three maternal and three perinatal risk factors associated with ROP. Genes EPAS1 and AGTR1, involved in angiogenesis and vascularization, were identified to be of risk for ROP.

IMPACT

Genetic and environmental risk factors associated with ROP and its comorbidities are evaluated in a Latin American population. Genes EPAS1 and AGTR1, involved in angiogenesis and vascularization, were identified to be of risk for ROP. Three maternal and three perinatal risk factors associated with ROP were also identified. A matrix of significant relationships among genetic markers and comorbidities is presented. Reported data may help develop more effective preventive measures for ROP in the Latin American region.

Mechanisms and functions of intestinal vascular specialization

The intestinal vasculature has been studied for the last 100 years, and its essential role in absorbing and distributing ingested nutrients is well known. Recently, fascinating new insights into the organization, molecular mechanisms, and functions of intestinal vessels have emerged. These include maintenance of intestinal epithelial cell function, coping with microbiota-induced inflammatory pressure, recruiting gut-specific immune cells, and crosstalk with other organs. Intestinal function is also regulated at the systemic and cellular levels, such that the postprandial hyperemic response can direct up to 30% of systemic blood to gut vessels, while micron-sized endothelial cell fenestrations are necessary for nutrient uptake. In this review, we will highlight past discoveries made about intestinal vasculature in the context of new findings of molecular mechanisms underpinning gut function. Such comprehensive understanding of the system will pave the way to breakthroughs in nutrient uptake optimization, drug delivery efficiency, and treatment of human diseases.

Role of the microbiome in pathophysiology of necrotising enterocolitis in preterm neonates

Although necrotising enterocolitis (NEC) is a serious, life-threatening disease, improved neonatal care is increasing the number of survivors with NEC among extremely preterm neonates. Therapy is nevertheless mostly symptomatic and the mortality rate remains high, especially among neonates requiring surgery. Therefore, it is important to focus on preventing the disease and modifiable risk factors. NEC's pathophysiology is multifaceted, with key factors being immaturity of the immune and barrier protective mechanisms of the premature gut and exaggerated proinflammatory reaction to insults like gut hypoxia, enteral nutrition or microbial dysbiosis. The role of the intestinal microbiome in the pathophysiology of NEC has been a subject of research for many years, but to date no specific pathogen or type of dysbiosis has been connected with NEC development. This review assesses current knowledge as to the role of the intestinal microbiota in the pathophysiology of NEC and the possibilities for positively influencing it.

From heart to gut: Exploring the gut microbiome in congenital heart disease

Congenital heart disease (CHD) is a prevalent birth defect and a significant contributor to childhood mortality. The major characteristics of CHD include cardiovascular malformations and hemodynamical disorders. However, the impact of CHD extends beyond the circulatory system. Evidence has identified dysbiosis of the gut microbiome in patients with CHD. Chronic hypoxia and inflammation associated with CHD affect the gut microbiome, leading to alterations in its number, abundance, and composition. The gut microbiome, aside from providing essential nutrients, engages in direct interactions with the host immune system and indirect interactions via metabolites. The abnormal gut microbiome or its products can translocate into the bloodstream through an impaired gut barrier, leading to an inflammatory state. Metabolites of the gut microbiome, such as short-chain fatty acids and trimethylamine N-oxide, also play important roles in the development, treatment, and prognosis of CHD. This review discusses the role of the gut microbiome in immunity, gut barrier, neurodevelopment, and perioperative period in CHD. By fostering a better understanding of the cross-talk between CHD and the gut microbiome, this review aims to contribute to improve clinical management and outcomes for CHD patients.

New insights into intestinal macrophages in necrotizing enterocolitis: the multi-functional role and promising therapeutic application

Necrotizing enterocolitis (NEC) is an inflammatory intestinal disease that profoundly affects preterm infants. Currently, the pathogenesis of NEC remains controversial, resulting in limited treatment strategies. The preterm infants are thought to be susceptible to gut inflammatory disorders because of their immature immune system. In early life, intestinal macrophages (IMφs), crucial components of innate immunity, demonstrate functional plasticity and diversity in intestinal development, resistance to pathogens, maintenance of the intestinal barrier, and regulation of gut microbiota. When the stimulations of environmental, dietary, and bacterial factors interrupt the homeostatic processes of IMφs, they will lead to intestinal disease, such as NEC. This review focuses on the IMφs related pathogenesis in NEC, discusses the multi-functional roles and relevant molecular mechanisms of IMφs in preterm infants, and explores promising therapeutic application for NEC.

Nailfold Capillaroscopy: A Promising, Noninvasive Approach to Predict Retinopathy of Prematurity

OBJECTIVE

To test the hypothesis that nailfold capillaroscopy can noninvasively detect dysregulated retinal angiogenesis and predict retinopathy of prematurity (ROP) in infants born premature before its development.

METHODS

In a cohort of 32 infants born <33 weeks of gestation, 1386 nailfold capillary network images of the 3 middle fingers of each hand were taken during the first month of life. From these, 25 infants had paired data taken 2 weeks apart during the first month of life. Images were analyzed for metrics of peripheral microvascular density using a machine learning-based segmentation approach and a previously validated microvascular quantification platform (REAVER vascular analysis). Results were correlated with subsequent development of ROP based on a published consensus ROP severity scale.

RESULTS

In total, 18 of 32 (56%) (entire cohort) and 13 of 25 (52%) (2-time point subgroup) developed ROP. Peripheral vascular density decreased significantly during the first month of life. In the paired time point analysis, vessel length density, a key metric of peripheral vascular density, was significantly greater at both time points among infants who later developed ROP (15 563 and 11 996 μm/mm2, respectively) compared with infants who did not (12 252 and 8845 μm/mm2, respectively) (P < .001, both time points). A vessel length density cutoff of >15 100 at T1 or at T2 correctly detected 3 of 3 infants requiring ROP therapy. In a mixed-effects linear regression model, peripheral vascular density metrics were significantly correlated with ROP severity.

CONCLUSIONS

Nailfold microvascular density assessed during the first month of life is a promising, noninvasive biomarker to identify premature infants at highest risk for ROP before detection on eye exam.

Recent advances in our understanding of NEC diagnosis, prognosis and surgical approach

Necrotising enterocolitis (NEC) remains a devasting condition that has seen limited improvement in outcomes in recent years. The incidence of the disease is increasing as more extremely premature infants survive. NEC is responsible for 1 in 10 neonatal deaths and up to 61% of survivors have significant neurodevelopmental delay. The aim of this review is to highlight recent advances in diagnosis, prognosis and surgical approach in this condition. Many recent studies have reported novel methods of diagnosis of NEC with the aim of earlier and more accurate identification. These include imaging and machine learning techniques. Prognostication of NEC is particularly important to allow earlier escalation of therapy. Around 25% of infants with NEC will require surgery and recent data has shown that time from disease onset to surgery is greater in infants whose indication for surgery is failed medical management, rather than pneumoperitoneum. This indication was also associated with worse outcomes compared to pneumoperitoneum. Ongoing research has highlighted several new methods of disease prognostication which includes differentiating surgical from medical NEC. Finally, recent randomised controlled trials in surgical technique are discussed along with the implications of these for practice. Further, high quality research utilising multi-centre collaborations and high fidelity data from electronic patient records is needed to address the issues discussed and ultimately improve outcomes in NEC.

Endothelial FOXC1 and FOXC2 promote intestinal regeneration after ischemia-reperfusion injury

Intestinal ischemia underlies several clinical conditions and can result in the loss of the intestinal mucosal barrier. Ischemia-induced damage to the intestinal epithelium is repaired by stimulation of intestinal stem cells (ISCs), and paracrine signaling from the vascular niche regulates intestinal regeneration. Here, we identify FOXC1 and FOXC2 as essential regulators of paracrine signaling in intestinal regeneration after ischemia-reperfusion (I/R) injury. Vascular endothelial cell (EC)- and lymphatic EC (LEC)-specific deletions of Foxc1, Foxc2, or both in mice worsen I/R-induced intestinal damage by causing defects in vascular regrowth, expression of chemokine CXCL12 and Wnt activator R-spondin 3 (RSPO3) in blood ECs (BECs) and LECs, respectively, and activation of Wnt signaling in ISCs. Both FOXC1 and FOXC2 directly bind to regulatory elements of the CXCL12 and RSPO3 loci in BECs and LECs, respectively. Treatment with CXCL12 and RSPO3 rescues the I/R-induced intestinal damage in EC- and LEC-Foxc mutant mice, respectively. This study provides evidence that FOXC1 and FOXC2 are required for intestinal regeneration by stimulating paracrine CXCL12 and Wnt signaling.

Photoacoustic Imaging as a Novel Non-Invasive Biomarker to Assess Intestinal Tissue Oxygenation and Motility in Neonatal Rats

Background

Within the premature infant intestine, oxygenation and motility play key physiological roles in healthy development and disease such as necrotizing enterocolitis. To date, there are limited techniques to reliably assess these physiological functions that are also clinically feasible for critically ill infants. To address this clinical need, we hypothesized that photoacoustic imaging (PAI) can provide non-invasive assessment of intestinal tissue oxygenation and motility to characterize intestinal physiology and health.

Methods

Ultrasound and photoacoustic images were acquired in 2-day and 4-day old neonatal rats. For PAI assessment of intestinal tissue oxygenation, an inspired gas challenge was performed using hypoxic, normoxic, and hyperoxic inspired oxygen (FiO2). For intestinal motility, oral administration of ICG contrast agent was used to compare control animals to an experimental model of loperamide-induced intestinal motility inhibition.

Results

PAI demonstrated progressive increases in oxygen saturation (sO2) as FiO2 increased, while the pattern of oxygen localization remained relatively consistent in both 2-day and 4-day old neonatal rats. Analysis of intraluminal ICG contrast enhanced PAI images yielded a map of the motility index in control and loperamide treated rats. From PAI analysis, loperamide significantly inhibited intestinal motility, with a 32.6% decrease in intestinal motility index scores in 4-day old rats.

Conclusion

These data establish the feasibility and application of PAI to non-invasively and quantitatively measure intestinal tissue oxygenation and motility. This proof-of-concept study is an important first step in developing and optimizing photoacoustic imaging to provide valuable insight into intestinal health and disease to improve the care of premature infants.

Highlights

Intestinal tissue oxygenation and intestinal motility are important biomarkers of intestinal physiology in health and disease of premature infants.This proof-of-concept preclinical rat study is the first to report application of photoacoustic imaging for the neonatal intestine.Photoacoustic imaging is demonstrated as a promising non-invasive diagnostic imaging method for quantifying intestinal tissue oxygenation and intestinal motility in premature infants.

Graphical abstract

A two-center retrospective study: association of early caffeine administration and oxygen radical diseases in neonatology in Chinese preterm neonates

Introduction

Since December 2012, the prophylactic use of caffeine to treat AOP in preterm infants has been approved in China. This study aimed to investigate the relationship between early caffeine treatment initiation and the incidence of oxygen radical diseases in neonatology (ORDIN) in Chinese preterm infants.

Methods

A retrospective study was conducted at two hospitals in South China, involving 452 preterm infants with gestational ages less than 37 weeks. The infants were divided into early (227 cases, initiating within 48 h after birth) and late (225 cases, initiating over 48 h after birth) caffeine treatment group. Logistic regression analysis and Receiver Operating Characteristic (ROC) curves were used to evaluate the association between early caffeine treatment and the incidence of ORDIN.

Results

The results showed that extremely preterm infants in early treatment group had a lower incidence of PIVH and ROP compared to those in the late treatment group (PIVH, 20.1% versus 47.8%, P = 0.02; ROP, 70.8% versus 89.9%, P = 0.025). Very preterm infants in the early treatment group had a lower incidence of BPD and PIVH compared to those in the late treatment group (BPD, 43.8% versus 63.1%, P = 0.002; PIVH, 9.0% versus 22.3%, P = 0.001). Moreover, VLBW infants who received early caffeine treatment exhibited a decreased incidence of BPD (55.9% versus 80.9%, P = 0.000), PIVH (11.8% versus 33.1%, P = 0.000), and ROP (69.9% versus 79.8%, P = 0.043) compared to those in the late treatment group. Infants in the early caffeine treatment showed a reduced likelihood of PIVH (adjusted odds ratio, 0.407; 95%CI, 0.188-0.846) but did not exhibit a significant association with other terms of ORDIN. ROC analysis revealed that early initiation of caffeine treatment was associated with lower risk of BPD, PIVH, and ROP in preterm infants.

Discussion

In conclusion, this study demonstrates that early initiation of caffeine treatment is associated with a decreased incidence of PIVH in Chinese preterm infants. Further prospective investigations are necessary to verify and elucidate the precise effects of early caffeine treatment on complications in preterm Chinese infants.

The impact of maternal stress on the development of necrotizing enterocolitis: A comprehensive review

Necrotizing Enterocolitis (NEC) is a devastating intestinal inflammatory disease with significant morbidity and mortality. Numerous predictors have been implicated in the development of NEC, with a relatively less emphasis on maternal factors. Pregnancy drives women into a new stage of life that increases their susceptibility to biological and psychological stress. Additionally, maternal stress during pregnancy has been linked to various complications that can negatively impact both the mother and the developing fetus. These detrimental effects are facilitated by various systemic modifications. Similarly, there is evidence from animal studies that suggest a relationship between maternal stress and the occurrence of NEC due to the alterations observed in neonates. In this review, we will (1) discuss the physiological and psychological burden of maternal stress and how it can be linked to NEC, (2) summarize various predictors and risk factors of NEC, and (3) discuss the most widely utilized animal models for assessing the effects of prenatal stress on offspring.

Genetic Polymorphisms of Vascular Endothelial Growth Factor in Neonatal Pathologies: A Systematic Search and Narrative Synthesis of the Literature

(1) Background: Vascular endothelial growth factor (VEGF) is essential in vasculo- and angiogenesis due to its role in endothelial cell proliferation and migration. As a vascular proliferative factor, VEGF is one of the hallmarks of cancer and, in adult populations, the relationship between genetic polymorphism and neoplasm was widely investigated. For the neonatal population, only a few studies attempted to uncover the link between the genetic polymorphism of VEGF and neonatal pathology, especially related to late-onset complications. Our objective is to evaluate the literature surrounding VEGF genetic polymorphisms and the morbidity of the neonatal period. (2) Methods: A systematic search was initially conducted in December 2022. The PubMed platform was used to explore MEDLINE (1946 to 2022) and PubMed Central (2000 to 2022) by applying the search string ((VEGF polymorphism*) and newborn*). (3) Results: The PubMed search yielded 62 documents. A narrative synthesis of the findings was undertaken considering our predetermined subheadings (infants with low birth weight or preterm birth, heart pathologies, lung diseases, eye conditions, cerebral pathologies, and digestive pathologies). (4) Conclusion: The VEGF polymorphisms seem to be associated with neonatal pathology. The involvement of VEGF and VEGF polymorphism has been demonstrated for retinopathy of prematurity.

State-of-the-art review and update of in vivo models of necrotizing enterocolitis

NEC remains one of the most common causes of mortality and morbidity in preterm infants. Animal models of necrotizing enterocolitis (NEC) have been crucial in improving our understanding of this devastating disease and identifying biochemical pathways with therapeutic potential. The pathogenesis of NEC remains incompletely understood, with no specific entity that unifies all infants that develop NEC. Therefore, investigators rely on animal models to manipulate variables and provide a means to test interventions, making them valuable tools to enhance our understanding and prevent and treat NEC. The advancements in molecular analytic tools, genetic manipulation, and imaging modalities and the emergence of scientific collaborations have given rise to unique perspectives and disease correlates, creating novel pathways of investigation. A critical review and understanding of the current phenotypic considerations of the highly relevant animal models of NEC are crucial to developing novel therapeutic and preventative strategies for NEC.

Global trend and future landscape of intestinal microcirculation research from 2000 to 2021: A scientometric study

BACKGROUND

The intestinal microcirculation functions in food absorption and metabolic substance exchanges. Accumulating evidence indicates that intestinal microcirculatory dysfunction is a significant source of multiple gastrointestinal diseases. To date, there has not been a scientometric analysis of intestinal microcirculatory research.

AIM

To investigate the current status, development trends, and frontiers of intestinal microcirculatory research based on bibliometric analysis.

METHODS

VOSviewer and CiteSpace 6.1.R2 were used to identify the overall characteristics and knowledge map of intestinal microcirculatory research based on the core literature published from 2000 to 2021 in the Web of Science database. The characteristics of each article, country of origin, institution, journal, cocitations, and other information were analyzed and visualized.

RESULTS

There were 1364 publications enrolled in the bibliometric analysis, exhibiting an upward trend from 2000 to 2021 with increased participation worldwide. The United States and Dalhousie University took the lead among countries and institutions, respectively. Shock was the most prolific journal, and Nature Reviews Microbiology Clinical had the most citations. The topical hotspots and frontiers in intestinal microcirculatory research were centered on the pathological processes of functional impairment of intestinal microvessels, diverse intestinal illnesses, and clinical treatment.

CONCLUSION

Our study highlights insights into trends of the published research on the intestinal microcirculation and offers serviceable guidance to researchers by summarizing the prolific areas in intestinal disease research to date.

Biomarkers of necrotizing enterocolitis in the era of machine learning and omics

Necrotizing enterocolitis (NEC) continues to be a major cause of morbidity and mortality in preterm infants. Despite decades of research in NEC, no reliable biomarkers can accurately diagnose NEC or predict patient prognosis. The recent emergence of multi-omics could potentially shift NEC biomarker discovery, particularly when evaluated using systems biology techniques. Furthermore, the use of machine learning and artificial intelligence in analyzing this 'big data' could enable novel interpretations of NEC subtypes, disease progression, and potential therapeutic targets, allowing for integration with personalized medicine approaches. In this review, we evaluate studies using omics technologies and machine learning in the diagnosis of NEC. Future implications and challenges inherent to the field are also discussed.

Necrotizing Enterocolitis: The Role of Hypoxia, Gut Microbiome, and Microbial Metabolites

Necrotizing enterocolitis (NEC) is a life-threatening disease that predominantly affects very low birth weight preterm infants. Development of NEC in preterm infants is accompanied by high mortality. Surgical treatment of NEC can be complicated by short bowel syndrome, intestinal failure, parenteral nutrition-associated liver disease, and neurodevelopmental delay. Issues surrounding pathogenesis, prevention, and treatment of NEC remain unclear. This review summarizes data on prenatal risk factors for NEC, the role of pre-eclampsia, and intrauterine growth retardation in the pathogenesis of NEC. The role of hypoxia in NEC is discussed. Recent data on the role of the intestinal microbiome in the development of NEC, and features of the metabolome that can serve as potential biomarkers, are presented. The Pseudomonadota phylum is known to be associated with NEC in preterm neonates, and the role of other bacteria and their metabolites in NEC pathogenesis is also discussed. The most promising approaches for preventing and treating NEC are summarized.

Necrotizing enterocolitis, gut microbes, and sepsis

Necrotizing enterocolitis (NEC) is a devastating disease in premature infants and the leading cause of death and disability from gastrointestinal disease in this vulnerable population. Although the pathophysiology of NEC remains incompletely understood, current thinking indicates that the disease develops in response to dietary and bacterial factors in the setting of a vulnerable host. As NEC progresses, intestinal perforation can result in serious infection with the development of overwhelming sepsis. In seeking to understand the mechanisms by which bacterial signaling on the intestinal epithelium can lead to NEC, we have shown that the gram-negative bacterial receptor toll-like receptor 4 is a critical regulator of NEC development, a finding that has been confirmed by many other groups. This review article provides recent findings on the interaction of microbial signaling, the immature immune system, intestinal ischemia, and systemic inflammation in the pathogenesis of NEC and the development of sepsis. We will also review promising therapeutic approaches that show efficacy in pre-clinical studies.

Clinical determinants and impact of hemorrhagic lesions on intestinal pathology in preterm infants with surgical necrotizing enterocolitis

OBJECTIVE

We sought to determine the clinical and histopathological factors associated with intestinal hemorrhage and its correlation with clinical outcomes in neonates with surgical necrotizing enterocolitis (NEC).

METHODS

A retrospective study compared clinical and histopathology information in neonates following surgical NEC with severe hemorrhage and those with mild/moderate hemorrhagic lesions seen on resected intestine pathology.

RESULTS

The infants with severe hemorrhage (Grade 3-4, 81/148, 54.7%) had significantly lower exposure to antenatal steroids (52.5 % vs 76.9 % ; p = 0.004), had higher gestational age (28.5 weeks [7.14] vs. 26.58 [2.90]; p = 0.034), lost more bowel length (p = 0.045), had higher CRP levels at 2 weeks (p = 0.035), and had less intestinal failure ([30.3 % vs 52.5 %]; p = 0.014) than mild/moderate (Grade 0-2, 67/148, 45.2%) hemorrhage group. Those with severe hemorrhage had significantly higher mean inflammation score (2.67 [0.94] vs. 1.63 [0.92]; p = <0.001), higher necrosis scores (1.95 [1.28] vs. 1.49 [1.35]; p = 0.037), higher neovascularization (p = 0.01), higher fibroblasts (p = 0.023) and higher lymphocyte percentages up to 48 hours (p <  0.05) following NEC than mild/ moderate hemorrhage group.On multivariable regression, less exposure to antenatal steroids (OR 0.18 [95% CI 0.05-0.58]; p = 0.005), higher inflammation (OR 3.7 [95% CI 2.09-7.32]; p = 0.001), and lymphocyte count on the day of onset/24 hours following NEC (OR 1.06 [95% CI 1.02-1.11]; p = 0.005) were independently associated with a higher odd of severe intestinal hemorrhage.

CONCLUSION

The surgical NEC infants with intestinal hemorrhage were less likely to have antenatal steroid exposure but had higher inflammation grade and lymphocyte counts following NEC onset on multivariable regression modeling.

Remote ischaemic pre-conditioning reduces intestinal ischaemia reperfusion injury in a newborn rat

OBJECTIVE

Remote ischaemic conditioning (RIC) has been shown to reduce ischaemia-reperfusion injury(IRI) in multiple organ systems. IRI is seen in multiple bowel pathologies in the newborn, including NEC. We investigated the potential of RIC as a novel therapy for various intestinal pathologies in the newborn.

METHODS

We used an established intestinal IRI model in rat pups which results in similar intestinal injury to necrotising enterocolitis (NEC). Animals were randomly allocated to IRI only(n = 14), IRI + RIC(n = 13) or sham laparotomy(n = 10). The macroscopic extent of intestinal injury is reported as a percentage of total small bowel. Injury severity was measured using Chiu-Park scoring. Neutrophil infiltration/activation was assayed by myeloperoxidase activity. Immunohistochemistry was used to assess the expression of hypoxia-inducible factor alpha (HIF-1α). Data are median (interquartile range).

RESULTS

Animals that underwent RIC showed a decreased extent of macroscopic injury from 100%(85-100%) in the IRI only group to 58%(15-84%, p = 0.003) in the IRI + RIC group. Microscopic injury score was significantly lower in animals that underwent RIC compared to IRI alone (3.5[1.25-5] vs 5.5[4-6], p = 0.014). Intestinal myeloperoxidase activity in animals exposed to IRI was 3.4 mU/mg of tissue (2.5-3.7) and 2.1 mU/mg(1.5-2.8) in the IRI + RIC group(p = 0.047). HIF-1α expression showed a non-significant trend towards reduced expression in the IRI + RIC group.

CONCLUSIONS

RIC reduces the extent and severity of bowel injury in this animal model, supporting the hypothesis that RIC has therapeutic potential for intestinal diseases in the newborn.

Intestinal atresia and necrotizing enterocolitis: Embryology and anatomy

The primitive gut originates at week 3 of gestation from the endoderm, with posterior incorporation of the remaining embryo layers. Wnt, Notch and TLR4 pathways have been shown to play central roles in the correct development of the intestine. The classical hypothesis for intestinal atresia development consists of failure in bowel recanalization or a vascular accident with secondary bowel reabsorption. These have been challenged due to the high frequency of associated malformations, and furthermore, with the discovery of molecular pathways and genes involved in bowel formation and correlated defects producing atresia. Necrotizing enterocolitis (NEC) has a multifactorial pathogenesis with prematurity being the most important risk factor; therefore, bowel immaturity plays a central role in NEC. Some of the same molecular pathways involved in gut maturation have been found to correlate with the predisposition of the immature bowel to develop the pathological findings seen in NEC.

Clinical and histopathological correlates of intestinal repair in preterm infants following surgical necrotizing enterocolitis

OBJECTIVE

We sought to determine the clinical and histopathological factors linked with intestinal repair and its correlation with clinical outcomes in preterm infants following surgical necrotizing enterocolitis (NEC).

METHODS

A retrospective study has compared clinical and histopathological characteristics between preterm infants with histopathological reparative changes versus non-reparative changes in resected intestinal tissue following surgical treatment of NEC. Reparative changes were defined as microscopic evidence of neovascularization, increased fibroblasts or myofibroblasts, and epithelial regeneration during histopathological examination of the most affected area of resected intestinal tissue.

RESULTS

The infants with reparative changes (53/148) had significantly lower median birth weight (725 [650-963] vs. 920 [690-1320]; p = .018), higher likelihood of patent ductus arteriosus (38/53 [71.7%] vs. 48/95 [50.5%]; p = .012), longer TPN days (99 [56-147] vs. 76.5 [39-112.5]; p = .034), higher CRP levels (7.3 [3.2-13] vs. 2.6 [1.1-7.8]; p = .011) at NEC onset, and more short bowel syndrome (27/53 [54.0%] vs. 28/95 [32.2%]; p = .012). Those with reparative changes also received more Penrose drain therapy (21/53 [39.6%] vs. 14/95 [14.7%]; p = .011) and had a longer median time to laparotomy (108 h [28-216] vs. 24 [12-96]; p = .003). Epithelial regeneration observed in 6/53 (11.3%) infants lagged fibroblast proliferation and neovascularization changes in the submucosa/muscularis intestinal layers. On a multivariable logistic regression model which included histopathological and clinical factors, inflammation with a percentage <25% area involvement, time from NEC diagnosis to surgery, and Apgar score < 6 at 5 min were independently and significantly associated with higher odds reparative changes.

CONCLUSION

In neonates with surgical NEC, the histopathological findings in the resected bowel are significantly associated with clinical characteristics, other histopathological findings, and outcomes. The presence of reparative changes consistent with healing is significantly associated with Apgar score, Penrose drain therapy, longer time from NEC diagnosis to surgery, and lower burden of inflammation in the resected bowel tissue in multivariable analyses. Routine histopathological grading of resected bowel and optimal use of Penrose drain therapy warrant further investigation in the care of neonates with surgical NEC.

[Value of intestinal regional oxygen saturation and C-reactive protein in the diagnosis of necrotizing enterocolitis in preterm infants]

OBJECTIVES

To study the clinical value of intestinal regional oxygen saturation (rSO₂) and C-reactive protein (CRP) in the diagnosis of necrotizing enterocolitis (NEC) in preterm infants.

METHODS

A prospective observational study was conducted among the preterm infants who were hospitalized in Children's Hospital Affiliated to Anhui Medical University, from October 2020 to December 2021, with 22 infants in the NEC group and 35 infants in the non-NEC group. Intestinal rSO₂ was monitored 24 hours after a confirmed diagnosis of NEC in the NEC group, and serum CRP levels were measured before anti-infection therapy. In the non-NEC group, intestinal rSO₂ monitoring and serum CRP level measurement were performed at the corrospording time points. The two groups were compared in terms of intestinal rSO₂ and serum CRP level. The receiver operating characteristic (ROC) curve was used to analyze the value of intestinal rSO₂ alone, serum CRP alone, and intestinal rSO₂ combined with CRP in the diagnosis of NEC in preterm infants.

RESULTS

Compared with the non-NEC group, the NEC group had a significantly lower level of intestinal rSO₂ (P<0.05) and a higher serum CRP level (P<0.05). The ROC curve analysis showed that intestinal rSO₂ had an optimal cut-off value of 50.75% in the diagnosis of NEC in preterm infants, with a sensitivity of 81.8%, a specificity of 85.7%, and an area under the ROC curve (AUC) of 89.4%; CRP had an optimal cut-off value of 12.05 mg/L in the diagnosis of NEC in preterm infant, with a sensitivity of 72.7%, a specificity of 74.3%, and an AUC of 74.8%; intestinal rSO₂ combined with CRP had a sensitivity of 90.9%, a specificity of 77.1%, and an AUC of 91.9% in the diagnosis of NEC. The AUC of intestinal rSO₂ alone in the diagnosis NEC was higher than that of CRP (P<0.05). There was no significant difference in the AUC between intestinal rSO₂ alone and intestinal rSO₂ combined with CRP (P>0.05).

CONCLUSIONS

The value of intestinal rSO₂ in the diagnosis NEC is higher than that of CRP, and is equivalent to that of the combination of intestinal rSO₂ and CRP in preterm infants.

Clinical Characteristics and Potential Pathogenesis of Cardiac Necrotizing Enterocolitis in Neonates with Congenital Heart Disease: A Narrative Review

Neonates with congenital heart disease (CHD) are at an increased risk of developing necrotizing enterocolitis (NEC), an acute inflammatory intestinal injury most commonly associated with preterm infants. The rarity of this complex disease, termed cardiac NEC, has resulted in a dearth of information on its pathophysiology. However, a higher incidence in term infants, effects on more distal regions of the intestine, and potentially a differential immune response may distinguish cardiac NEC as a distinct condition from the more common preterm, classical NEC. In this review, risk factors, differentiated from those of classical NEC, are discussed according to their potential contribution to the disease process, and a general pathogenesis is postulated for cardiac NEC. Additionally, biomarkers specific to cardiac NEC, clinical outcomes, and strategies for achieving enteral feeds are discussed. Working towards an understanding of the mechanisms underlying cardiac NEC may aid in future diagnosis of the condition and provide potential therapeutic targets.

Bench to bedside - new insights into the pathogenesis of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the leading cause of death and disability from gastrointestinal disease in premature infants. Recent discoveries have shed light on a unifying theorem to explain the pathogenesis of NEC, suggesting that specific treatments might finally be forthcoming. A variety of experiments have highlighted how the interaction between bacterial signalling receptors on the premature intestine and an abnormal gut microbiota incites a pro-inflammatory response in the intestinal mucosa and its underlying endothelium that leads to NEC. Central amongst the bacterial signalling receptors implicated in NEC development is the lipopolysaccharide receptor Toll-like receptor 4 (TLR4), which is expressed at higher levels in the premature gut than in the full-term gut. The high prenatal intestinal expression of TLR4 reflects the role of TLR4 in the regulation of normal gut development, and supports additional studies indicating that NEC develops in response to signalling events that occur in utero. This Review provides new evidence explaining the pathogenesis of NEC, explores new findings indicating that NEC development has origins before birth, and discusses future questions and opportunities for discovery in this field.

Neuroprotective Effects of VEGF in the Enteric Nervous System

Although the enteric nervous system (ENS) functions largely autonomously as part of the peripheral nervous system (PNS), it is connected to the central nervous system (CNS) via the gut–brain axis. In many neurodegenerative diseases, pathological changes occur in addition to gastrointestinal symptoms, such as alpha-synuclein aggregates in Parkinson’s disease, which are found early in the ENS. In both the CNS and PNS, vascular endothelial growth factor (VEGF) mediates neuroprotective and neuroregenerative effects. Since the ENS with its close connection to the microbiome and the immune system is discussed as the origin of neurodegenerative diseases, it is necessary to investigate the possibly positive effects of VEGF on enteric neurons. Using laser microdissection and subsequent quantitative RT-PCR as well as immunohistochemistry, for the first time we were able to detect and localize VEGF receptor expression in rat myenteric neurons of different ages. Furthermore, we demonstrate direct neuroprotective effects of VEGF in the ENS in cell cultures. Thus, our results suggest a promising approach regarding neuroprotection, as the use of VEGF (may) prevent neuronal damage in the ENS.

Intestinal perforation after intravitreal low dose ranibizumab injection for the treatment of type 1 retinopathy of prematurity: A case report

PURPOSE

To report a newborn patient with gastrointestinal (GIS) perforation after intravitreal ranibizumab (RBZ) treatment.

CASE REPORT

The patient was born at 31 gestational week and hospitalized with the diagnosis of small for gestational age and prematurity. In the follow up he underwent GIS surgery due to necrotizing enterocolitis (NEC) and was diagnosed with retinopathy of prematurity (ROP). At 43 weeks of postmenstrual age, he developed intestinal perforation after 12 h of the second low-dose RBZ injection. According to our knowledge, this is the first report of GIS perforation due to low-dose intravitreal RBZ treatment in an infant with severe ROP.

CONCLUSION

The risk of GIS perforation should be taken into consideration during the application of intravitreal vascular endothelial growth factor antagonist agents, especially in newborns with previous GIS surgery and a history of NEC, and these patients should be carefully monitored for GIS complications.

Advances in our understanding of the molecular pathogenesis of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a multifactorial and complex disease. Our knowledge of the cellular and genetic basis of NEC have expanded considerably as new molecular mechanisms have been identified. This article will focus on the current understanding of the molecular pathogenesis of NEC with a focus on the inflammatory, immune, infectious, and genetic mechanisms that drive disease development.

Red blood cell transfusions post diagnosis of necrotizing enterocolitis and the deterioration of necrotizing enterocolitis in full-term and near-term infants: a propensity score adjustment retrospective cohort study

Background

Necrotizing enterocolitis (NEC) is one of serious gastrointestinal inflammatory diseases in newborn infants, with a high morbidity and mortality. Red blood cell transfusion (RBCT) plays a controversial and doubtful role in the treatment of NEC. In present study, we aim to analyze the association between RBCT and the deterioration of NEC.

Methods

This was a retrospective cohort study of near-term and full-term infants with a confirmed diagnosis of Bell’s stage II NEC between Jan 1, 2010 and Jan 31, 2020. The maternal and infant baseline characteristics, treatment information and laboratory test for each case were collected. The eligible subjects were divided into two groups based on receiving RBCT post NEC diagnosis or not. The propensity score was used to eliminate potential bias and baseline differences. A multivariate logistic regression model was used to adjust the propensity score and calculate the odds ratio (OR) and 95% confidential interval (CI) of RBCT for the deterioration of NEC.

Results

A total of 242 infants were included in this study, 60 infants had a history of RBCT post NEC diagnosis, and 40 infants deteriorated from Bell’s stage II to stage III. By adjusting the propensity score, RBCT post NEC diagnosis was associated with an increased risk for NEC deteriorating from stage II to III (adjusted OR 6.06, 95%CI 2.94–12.50, P = 0.000).

Conclusions

NEC infants who required RBCT post NEC diagnosis were more likely to deteriorate from stage II to III in full-term and near-term infants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03276-4.

Macrophage-derived IGF-1 protects the neonatal intestine against necrotizing enterocolitis by promoting microvascular development

Necrotizing enterocolitis (NEC) is a deadly bowel necrotic disease of premature infants. Low levels of plasma IGF-1 predispose premature infants to NEC. While increasing evidence suggests that defective perinatal intestinal microvascular development plays a role in NEC, the involved mechanism remains incompletely understood. We report here that serum and intestinal IGF-1 are developmentally regulated during the perinatal period in mice and decrease during experimental NEC. Neonatal intestinal macrophages produce IGF-1 and promote endothelial cell sprouting in vitro via IGF-1 signaling. In vivo, in the neonatal intestine, macrophage-derived IGF-1 promotes VEGF expression and endothelial cell proliferation and protects against experimental NEC. Exogenous IGF-1 preserves intestinal microvascular density and protects against experimental NEC. In human NEC tissues, villous endothelial cell proliferation and IGF-1- producing macrophages are decreased compared to controls. Together, our results suggest that defective IGF-1-production by neonatal macrophages impairs neonatal intestinal microvascular development and predisposes the intestine to necrotizing enterocolitis.

Single Nucleotide Polymorphisms in Neonatal Necrotizing Enterocolitis

The etiopathogenesis of necrotizing enterocolitis (NEC) remains unclear, but increasing information suggests that the risk and severity of NEC may be influenced by single nucleotide polymorphisms in many genes. In this article, we have reviewed gene variations that have either been specifically identified in NEC or have been noted in other inflammatory bowel disorders with similar histopathological abnormalities. We present evidence from our own peer-reviewed laboratory studies and data from an extensive literature search in the databases PubMed, EMBASE, and Scopus. To avoid bias in the identification of existing studies, search keywords were short-listed both from our own studies and from PubMed's Medical Subject Heading (MeSH) thesaurus.

The Impact of MicroRNAs in Neonatal Necrotizing Enterocolitis and other Inflammatory Conditions of Intestine: A Review

The understanding of necrotizing enterocolitis (NEC) etiopathogenesis is incomplete, contributing to the lack of early biomarkers and therapeutic options. Micro RNAs (miRNAs) are a class of RNAs that can alter gene expression and modulate various physiological and pathological processes. Several studies have been performed to evaluate the role of miRNA in the pathogenesis of NEC. In this article, we review the information on miRNAs that have been specifically identified in NEC or have been noted in other inflammatory bowel disorders that share some of the histopathological abnormalities seen frequently in NEC. This review highlights miRNAs that could be useful as early biomarkers of NEC and suggests possible approaches for future translational studies focused on these analytes. It is a novel field with potential for immense translational and clinical relevance in preventing, detecting, or treating NEC in very premature infants. Impact • Current information categorizes necrotizing enterocolitis (NEC) as a multifactorial disease, but microRNAs (miRNAs) may influence the risk of occurrence of NEC. • MiRNAs may alter the severity of the intestinal injury and the clinical outcome of NEC. • The literature on intestinal diseases of adults suggests additional miRNAs that have not been studied in NEC yet but share some features and deserve further exploration in human NEC, especially if affecting gut dysbiosis, intestinal perfusion, and coagulation disorders.

Clinical Presentation and Multifactorial Pathogenesis of Necrotizing Enterocolitis in the Preterm Infant

BACKGROUND

Necrotizing enterocolitis (NEC) is a serious infection of the bowel wall induced by multiple pathological factors, which include inflammation and tissue invasion with bacteria known to cause severe infections. NEC is now understood to be several disease processes under one umbrella. The most common form occurs in premature infants and can exert significant impacts to preterm morbidity and mortality.

PURPOSE

This narrative review describes current knowledge of the clinical presentation and pathophysiology of NEC in premature infants.

METHODS/SEARCH STRATEGY

A review of literature was conducted using key words in PubMed and CINAHL with preference for years 2015 to 2020.

FINDINGS/RESULTS

Several converging and interrelated factors including characteristics of the premature intestinal mucosa, gut ischemia, dysregulation of the microbiome, enteral feeding, and genetics create an environment where NEC is more likely to occur.

IMPLICATIONS FOR PRACTICE

To recognize and diagnose NEC in preterm infants, an understanding of underlying factors that create an optimal environment for disease acquisition in premature infants is essential.

IMPLICATIONS FOR RESEARCH

Prevention of NEC remains the most important strategy for decreasing morbidity and mortality. Multiple areas of potential study exist for NEC pathophysiology including those that consider how the factors discussed in this review are interrelated and how each particular pathway can be optimized to prevent the onset of NEC.

Effects of Caffeine on Splanchnic Oxygenation in Preterm Infants

OBJECTIVE

The aim of this study is to assess the effects of administering 20 mg/kg loading dose of caffeine citrate intravenously on splanchnic oxygenation in preterm infants.

STUDY DESIGN

The infants with a gestational age (GA) of <34 weeks who were administered with a 20 mg/kg intravenous loading dose of caffeine citrate within 48 hours after birth were investigated prospectively. Regional splanchnic oxygen saturation (rsSO₂) and splanchnic fractional tissue oxygen extraction rate (sFTOE) were measured using near-infrared spectroscopy before caffeine infusion, immediately after caffeine infusion and 1, 2, 3, 4, and 6 hours (h) after dose completion; postdose values were compared with predose values.

RESULTS

A total of 41 infants with a mean GA of 29.2 ± 1.6 weeks and birth weight of 1,315 ± 257 g as well as postnatal age of 32.2 ± 10.8 hours were included in the study. rsSO₂ significantly reduced from 63.1 to 57.5% immediately after caffeine infusion, 55.1% after 1 hour, and 55.2% after 2 hours with partial recovery at 3-hour postdose. sFTOE increased correspondingly.

CONCLUSION

Caffeine reduces splanchnic oxygenation and increases splanchnic oxygen extraction for at least 2 hours with partial recovery to predose levels at 3-hour postdose.

Antenatal magnesium sulfate and intestinal morbidities in preterm infants with extremely low gestational age

BACKGROUND

Antenatal magnesium sulfate is widely used as a tocolytic, for maternal seizures, and for seizure prophylaxis in preeclampsia. Recent studies have suggested that antenatal magnesium sulfate use is associated with favorable neurodevelopmental outcomes in preterm infants. However, there are concerns regarding the effects of antenatal magnesium sulfate on neonates, especially regarding gastrointestinal morbidities. This study aims to explore the effects of antenatal magnesium sulfate on intestinal morbidities requiring surgery in preterm infants.

METHODS

This was a retrospective cohort study of 181 preterm infants who were born at less than 28 weeks of gestational age. Subjects were categorized as infants exposed to antenatal magnesium sulfate and those not exposed to antenatal magnesium sulfate.

RESULTS

Antenatal magnesium sulfate was associated with a decreased risk of surgical conditions of the intestine (OR 0.393, 95% CI 0.170-0.905). The multivariate analysis showed that the duration of antenatal magnesium sulfate use was associated with surgical conditions of the intestine (adjusted OR 0.766, 95% CI 0.589-0.997). In the <26 weeks of gestational age subgroup, the use of antenatal magnesium sulfate was significantly associated with decreased intestinal morbidities requiring surgery (adjusted OR 0.234, 95% CI 0.060-0.922).

CONCLUSION

Antenatal magnesium sulfate use appears to have a protective effect on intestinal morbidities requiring surgery in preterm infants in a duration-dependent manner. Association of antenatal magnesium sulfate use and decreased intestinal morbidities requiring surgery was more distinct in preterm infants <26 weeks of gestational age.

Deformability of cord blood vs. newborns' red blood cells: implication for blood transfusion

AIM

About 50% of premature neonates (PN) are treated with transfusion of packed red blood cells (PRBC) collected from adult donors, which has been suggested to potentially provoke PN pathologies, characterized as blood circulation disorders. RBC have properties that are key determinants of blood circulation, primarily the cell deformability. In previous studies we have shown that transfusion of RBC with reduced deformability impaired the transfusion outcome. Although RBC of PN (PN-RBC) are larger, and their microvessels are narrower than those of adults, their blood circulation is very efficient, pointing to the possibility that the deformability of adults' PRBC is inferior to that of PN-RBC, and that treating PN with PRBC transfusion might, therefore, introduce a risk to the recipients. This would infer that PN should be given RBC with high deformability. However, since using PN-RBC is not feasible, the use of cord blood RBC (CB-RBC) is a sound alternative, assuming that the deformability of CB-RBC is comparable to that of PN-RBC.The present study is aimed at testing this hypothesis.

METHODS

We compared the deformability of (1) RBC of PN vs. the PRBC they received, and (2) PN-RBC vs. their autologous CB-RBC.

RESULTS

1. The deformability of the transfused PRBC is indeed inferior to that of PN-RBC. 2. The deformability of CB-RBC is equivalent to that of PN-RBC.

CONCLUSION

This study supports the notion that treating PN with transfusion of adults' PRBC has the potential to introduce a circulatory risk to the recipients, while CB-RBC, with their superior deformability, provides a safer and more effective PN-specific transfusion therapy.

DNA Methylation of TLR4, VEGFA, and DEFA5 Is Associated With Necrotizing Enterocolitis in Preterm Infants

Background: Epigenetic changes, such as DNA methylation, may contribute to an increased susceptibility for developing necrotizing enterocolitis (NEC) in preterm infants. We assessed DNA methylation in five NEC-associated genes, selected from literature: EPO, VEGFA, ENOS, DEFA5, and TLR4 in infants with NEC and controls. Methods: Observational cohort study including 24 preterm infants who developed NEC (≥Bell Stage IIA) and 45 matched controls. DNA was isolated from stool samples and methylation measured using pyrosequencing. We investigated differences in methylation prior to NEC compared with controls. Next, in NEC infants, we investigated methylation patterns long before, a short time before NEC onset, and after NEC. Results: Prior to NEC, only TLR4 CpG 2 methylation was increased in NEC infants (median = 75.4%, IQR = 71.3-83.8%) versus controls (median = 69.0%, IQR = 64.5-77.4%, p = 0.025). In NEC infants, VEGFA CpG 3 methylation was 0.8% long before NEC, increasing to 1.8% a short time before NEC and 2.0% after NEC (p = 0.011; p = 0.021, respectively). A similar pattern was found in DEFA5 CpG 1, which increased from 75.4 to 81.4% and remained 85.3% (p = 0.027; p = 0.019, respectively). These changes were not present for EPO, ENOS, and TLR4. Conclusion: Epigenetic changes of TLR4, VEGFA, and DEFA5 are present in NEC infants and can differ in relation to the time of NEC onset. Differences in DNA methylation of TLR4, VEGFA, and DEFA5 may influence gene expression and increase the risk for developing NEC. This study also demonstrates the use of human DNA extraction from stool samples as a novel non-invasive method for exploring the bowel of preterm infants and which can also be used for necrotizing enterocolitis patients.

Incomplete resection of necrotic bowel may increase mortality in infants with necrotizing enterocolitis

BACKGROUND

Infants with advanced necrotizing enterocolitis (NEC) often need surgical resection of necrotic bowel. We hypothesized that incomplete resection of NEC lesions, signified by the detection of necrotic patches in margins of resected bowel loops, results in inferior clinical outcomes.

METHODS

We reviewed the medical records of infants with surgical NEC in the past 15 years for demographic, clinical, and histopathological data. We also developed statistical models to predict mortality and hospital stay.

RESULTS

Ninety infants with surgical NEC had a mean (±standard error) gestational age of 27.3 ± 0.4 weeks, birth weight 1008 ± 48 g, NEC onset at 25.2 ± 2.4 days, and resected bowel length of 29.2 ± 3.2 cm. Seventeen (18.9%) infants who had complete resection of the necrosed bowel had fewer (4; 23.5%) deaths and shorter lengths of hospital stay. In contrast, a group of 73 infants with some necrosis within the margins of resected bowel had significantly more (34; 46.6%) deaths and longer hospital stay. The combination of clinical and histopathological data gave better regression models for mortality and hospital stay.

CONCLUSION

In surgical NEC, incomplete resection of necrotic bowel increased mortality and the duration of hospitalization. Regression models combining clinical and histopathological data were more accurate for mortality and the length of hospital stay.

IMPACT

In infants with surgical NEC, complete resection of necrotic bowel reduced mortality and hospital stay. Regression models combining clinical and histopathological information were superior at predicting mortality and hospital stay than simpler models focusing on either of these two sets of data alone. Prediction of mortality improved with the combination of antenatal steroids, chorioamnionitis, and duration of post-operative ileus, with severity of inflammation and hemorrhages in resected intestine. Length of hospital stay was shorter in infants with higher gestational ages, but longer in those with greater depth of necrosis or needing prolonged parenteral nutrition or supervised feedings.

New Strategies for Necrotizing Enterocolitis Diagnosis and Prevention in Newborns

Necrotizing enterocolitis is one of the most frequent and severe gastrointestinal diseases that affect preterm newborns in Neonatal Intensive Care Units. It was firstly described in 1960s, but this clinical entity was not widely recognized until the advent of modern neonatal intensive care. The disease is characterized by submucosal edema, infiltration of intestinal wall by immune cells, specifically neutrophils and, in severe forms, wall necrosis that leads to intestinal perforation. Its incidence is inversely associated to birth weight and gestational age. Necrotizing enterocolitis has been responsible for high rates of morbidity and mortality (15-30%), despite improvements made in neonatal care in the last decades. The challenge is to optimize strategies for early diagnosis, define the best medical and surgical treatments and standardize preventive measures. Several biomarkers have been proposed for the early prediction of necrotizing enterocolitis onset in preterm newborns and can be useful not only for diagnostic purposes but also for prediction of disease progression and severity. The purpose of this paper is to illustrate the most recent evidence regarding the diagnosis and prevention of necrotizing enterocolitis. This manuscript contributes to clinical decision-making in preterm neonates at high risk of developing necrotizing enterocolitis.

Mesenteric neovascularization during spring-mediated intestinal lengthening

BACKGROUND

Short gut syndrome, a condition characterized by inadequate absorption of nutrients owing to decreased bowel length, has minimal avenues for treatment. We have proposed spring-mediated distraction enterogenesis to lengthen bowel in porcine jejunum as a treatment for short gut. We aim to evaluate the extent of mesenteric neovascularization in segments of lengthened bowel via spring-mediated enterogenesis.

METHODS

Female juvenile Yucatan pigs underwent laparotomy and insertion of gelatin-encapsulated compressed nitinol springs, held in place with plication sutures, into the jejunum. At surgery and sacrifice, macroscopic mesenteric blood vessels were counted between the plication sites. Histologic samples of the mesentery were obtained to evaluate microscopic vasculature.

RESULTS

A statistically significant increase in macroscopic mesenteric blood vessels was seen after intestinal lengthening (before: 1.9 ± 0.7 vessels, after: 4.7 ± 1.2 vessels, p = 0.001). A statistical significance is also seen in the density of arterioles (control: 3.0 ± 3.0 vessels/mm, spring: 7.0 ± 9.0 vessels/mm, p = 0.01) and venules (control: 4.0 ± 3.0 vessels/mm, spring: 8.0 ± 8.0 vessels/mm, p = 0.003).

CONCLUSION

Intestinal segments lengthened by intraluminal springs demonstrated total greater number of macroscopic vessels and microscopic blood vessels per length of mesentery as compared to control. This suggests local changes within the mesentery to recruit blood supply to growing intestine.

LEVEL OF EVIDENCE

N/A TYPE OF STUDY: Treatment study.

Stem Cells as Therapy for Necrotizing Enterocolitis: A Systematic Review and Meta-Analysis of Preclinical Studies

Background: Necrotizing enterocolitis (NEC) is the most common life-threatening gastrointestinal condition among very and extremely preterm infants. Stem cell therapy has shown some promising protective effects in animal models of intestinal injury, including NEC, but no systematic review has yet evaluated the preclinical evidence of stem cell therapy for NEC prevention or treatment. Methods: PubMed and EMBASE databases were searched for studies using an animal model of NEC with stem cells or their products. The SYRCLE tool was used for the assessment of risk of bias. A random-effects model was used to pool odds ratios (ORs) and 95% confidence interval (CI). Results: We screened 953 studies, of which nine (eight rat and one mouse models) met the inclusion criteria. All animal models induced NEC by a combination of hypothermia, hypoxia, and formula feeding. Risk of bias was evaluated as unclear on most items for all studies included. Meta-analysis found that both mesenchymal and neural stem cells and stem cell-derived exosomes reduced the incidence of all NEC (OR 0.22, 95% CI 0.16-0.32, k = 16), grade 2 NEC (OR 0.41, 95% CI 0.24-0.70, k = 16), and grade 3-4 NEC (OR 0.28, 95% CI 0.19-0.42, k = 16). k represents the number of independent effect sizes included in each meta-analysis. The effect of the exosomes was similar to that of the stem cells. Stem cells and exosomes also improved 4-day survival (OR 2.89 95% CI 2.07-4.04, k = 9) and 7-day survival (OR 3.96 95% CI 2.39-6.55, k = 5) after experimental NEC. Meta-analysis also found that stem cells reduced other indicators of intestinal injury. Conclusion: The data from this meta-analysis suggest that both stem cells and stem cell-derived exosomes prevented NEC in rodent experimental models. However, unclear risk of bias and incomplete reporting underline that poor reporting standards are common and hamper the reliable interpretation of preclinical evidence for stem cell therapy for NEC.

Nesfatin-1 ameliorates oxidative bowel injury in rats with necrotizing enterocolitis: The role of the microbiota composition and claudin-3 expression

BACKGROUND AND PURPOSE

Ongoing high mortality due to necrotizing enterocolitis (NEC) necessitates the investigation of novel treatments to improve the outcome of the affected newborns. The aim was to elucidate the potential therapeutic impact of the nesfatin-1, a peptide with anti-inflammatory and anti-apoptotic effects in several inflammatory processes, on NEC-induced newborn rats.

MATERIALS AND METHODS

Sprague-Dawley pups were separated from their mothers, fed with a hyperosmolar formula and exposed to hypoxia, while control pups had no intervention. NEC-induced pups received saline or nesfatin-1 (0.2 μg/kg/day) for 3 days, while some nesfatin-1 treated pups were injected with capsaicin (50 μg/g) for the chemical ablation of afferent neurons. On the 4th day, clinical state and macroscopic gut assessments were made. In intestines, immunohistochemical staining of cycloxygenase-2 (COX-2), nuclear factor (NF)-κB-p65 (RelA), vascular endothelial growth factor (VEGF), claudin-3 and zonula occludens-1 (ZO-1) were performed, while gene expressions of COX-2, occludin, claudin-3, NF-κB-p65 (RelA) and VEGF were determined using q-PCR. In fecal samples, relative abundance of bacteria was quantified by q-PCR. Biochemical evaluation of oxidant/antioxidant parameters was performed in both intestinal and cerebral tissues.

RESULTS

Claudin-3 and ZO-1 immunoreactivity scores were significantly elevated in the nesfatin-1 treated control pups. Nesfatin-1 reduced NEC-induced high macroscopic and clinical scores, inhibited NF-κB-65 pathway and maintained the balance of oxidant/antioxidant systems. NEC increased the abundance of Proteobacteria with a concomitant reduction in Actinobacteria and Bacteroidetes, while nesfatin-1 treatment reversed these alterations. Modulatory effects of nesfatin-1 on microbiota and oxidative injury were partially reversed by capsaicin. Immunohistochemistry demonstrated that nesfatin-1 abolished NEC-induced reduction in claudin-3. Gene expressions of COX-2, NF-κB, occludin and claudin-3 were elevated in saline-treated NEC pups, while these up-regulated mRNA levels were not further altered in nesfatin-1-treated NEC pups.

CONCLUSION

Nesfatin-1 could be regarded as a potential preventive agent for the treatment of NEC.

Imaging of the Intestinal Microcirculation during Acute and Chronic Inflammation

Because of its unique microvascular anatomy, the intestine is particularly vulnerable to microcirculatory disturbances. During inflammation, pathological changes in blood flow, vessel integrity and capillary density result in impaired tissue oxygenation. In severe cases, these changes can progress to multiorgan failure and possibly death. Microcirculation may be evaluated in superficial tissues in patients using video microscopy devices, but these techniques do not allow the assessment of intestinal microcirculation. The gold standard for the experimental evaluation of intestinal microcirculation is intravital microscopy, a technique that allows for the in vivo examination of many pathophysiological processes including leukocyte-endothelial interactions and capillary blood flow. This review provides an overview of changes in the intestinal microcirculation in various acute and chronic inflammatory conditions. Acute conditions discussed include local infections, severe acute pancreatitis, necrotizing enterocolitis and sepsis. Inflammatory bowel disease and irritable bowel syndrome are included as examples of chronic conditions of the intestine.

Hope on the horizon: promising novel therapies for necrotizing enterocolitis

Necrotizing enterocolitis (NEC) remains among the most common and devastating diseases in neonates. Despite advances in neonatal clinical care, specific treatment strategies and diagnostic modalities remain lacking. As a result, morbidity and mortality remain high. Improved understanding of the pathogenesis of NEC has the potential for improved therapeutics. Some of the areas of research leading to promising discoveries include inhibition of Toll-like receptor signaling, modulation of vascular endothelial growth factor signal pathways, defining metabolomic alterations in NEC to discover potential biomarkers, probing for genetic predispositions to NEC susceptibility, determining mechanistic relations between anemia and NEC, and microflora modulation through the use of probiotics. All of these areas may represent novel promising approaches to the prevention and treatment of NEC. This review will focus on these current and possible therapeutic perspectives.

Developmental 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure of either parent enhances the risk of necrotizing enterocolitis in neonatal mice

BACKGROUND

Necrotizing enterocolitis (NEC) is a rare, but potentially fatal intestinal inflammatory condition most often arising in premature infants. Infants provided formula are also at greater risk of developing this disease. Although the majority of formula-fed, preterm infants do not develop NEC, up to 30% of infants with the disease do not survive. Thus, identifying additional, currently unrecognized factors, which may predispose a specific infant to NEC development would be a significant clinical advancement. In this regard, we have previously reported that offspring of female or male mice with a history of developmental exposure to the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exhibit altered sensitivity to inflammatory challenges and are frequently born premature. Herein, we examined the possibility that, compared to unexposed mice (F1_NONE ), developmental TCDD exposure of either parent (maternal, F1M_TCDD , or paternal, F1P_TCDD ) would enhance the risk of NEC in offspring (F2_TCDD mice) in association with supplemental formula feeding.

METHODS

Beginning on postnatal day 7, all neonates were randomized to maternal milk only or maternal milk with up to 20 supplemental formula feedings. All pups remained with the Dams and were additionally allowed to nurse ad libitum.

RESULTS

Formula-fed F2_NONE pups rarely developed NEC while this disease was common in formula-fed F2M_TCDD and F2P_TCDD mice. Unexpectedly, 50% of F2M_TCDD pups that were not provided supplemental formula also developed NEC.

CONCLUSIONS

Our studies provide evidence that a history of parental TCDD exposure enhances the risk of NEC in offspring and suggest exposure to environmental immunotoxicants such as TCDD may also contribute to this inflammatory disease in humans.