Current Understanding of Transfusion-associated Necrotizing Enterocolitis: Review of Clinical and Experimental Studies and a Call for More Definitive Evidence

Necrotizing Enterocolitis: Pathogenetic Features and Differential Diagnosis with Inflammatory Bowel Disease in Newborns

Necrotizing enterocolitis (NEC) is a disease primarily affecting premature infants. NEC pathogenesis is based on the development of inflammation damaging mucous membranes associated with bacterial colonization, intestinal epithelium immaturity, intestinal blood flow regulation, and excessive inflammatory response activation. Inflammatory bowel disease (IBD) with very early onset (VEO-IBD) can also manifest in the neonatal period. They are characterized by severe course, often resistant to traditional immunosuppressive therapy. This article discusses the features of NEC pathogenesis and differential diagnosis with VEO-IBD. Despite certain similarities in pathogenesis, NEC and IBD are different diseases. Infantile onset IBD is more often associated with monogenic diseases and primary immunodeficiency. VEO-IBD is a chronic disease characterized by damage to all intestinal layers and has a lower incidence compared to NEC. Its clinical manifestations may include chronic diarrhea, blood in stool, delayed physical development, perianal diseases, and ulcerations in the oral cavity. Infantile onset VEO-IBD usually affects the colon, while NEC affects the ileum in premature infants. The intestinal microbiome in VEO-IBD also has specific features. It has been reported that clinical cases of Crohn’s disease in patients who had NEC in the neonatal period are associated with NEC surgery. It is crucial to consider perinatal period features when assessing the IBD risk (prenatal effects of antibacterial therapy and smoking, several courses of antibacterial therapy during the first year of life, and formula feeding).

Comparison of Necrotizing Enterocolitis After Surgical Norwood versus Hybrid Stage 1 Palliation

Hybrid stage 1 palliation (HS1P) is used as an alternative to the surgical Norwood for single ventricle patients and specific other conditions. Necrotizing enterocolitis (NEC) occurs in 5%-18% of infants after surgical Norwood, contributing to significant morbidity. We sought to compare the NEC incidences in HS1P versus Norwood patients. A single-center retrospective cohort study of all infants undergoing HS1P or Norwood over a 12-year period. Demographics, underlying cardiac diagnosis, surgical details, and NEC episodes were queried for each patient. The cumulative incidences of NEC between HS1P and Norwood patients were compared. A total of 305 infants were included; 200 Norwood and 105 HS1P. HS1P infants were more often premature (gestational age < 37 weeks; 23.8% vs 1.5%) and had lower birth weight (mean 2.8 ± 0.66 kg versus 3.3 ± 0.47 kg) than their Norwood counterparts. Most infants who underwent the Norwood procedure had hypoplastic left heart syndrome (79.5%), with variable underlying cardiac diagnosis for those who underwent HS1P. Incidence of NEC was significantly higher in the HS1P group (53.3% versus 37.0%, p = 0.01), with increased risk independent of birth weight or underlying cardiac diagnosis (adjusted odds ratio 1.8, p = 0.03). Infants after HS1P had a median of 2 episodes of NEC (interquartile range [IQR] 1-3) versus 1 episode in the Norwood group (IQR 1-2). Infants after HS1P are at higher risk of NEC in comparison to infants after the Norwood procedure. More studies are needed to help predict which infants after HS1P are at highest risk for NEC.

Transfusion-associated necrotising enterocolitis in very low birth weight babies: transfusion and feeding practices in two neonatal units in Bloemfontein, Free State

Background

Necrotising enterocolitis (NEC) is life-threatening with a rising incidence due to improved neonatal care. While researchers' focus has shifted to causes, risk factors and preventative clinical strategies, little is known about the exact aetiology of NEC. Risk factors include the relationship between red blood cell transfusions (RBCTs) and the development of transfusion-associated NEC (TANEC) and peri-transfusion feeding, increasing the risk of TANEC.

Objectives

Evaluate the relationship between RBCT and peri-transfusion feeding practices and the development of TANEC in very low birthweight (VLBW) neonates over 5 years.

Methods

This was a retrospective analytical record review of all VLBW neonates admitted to two tertiary hospitals' neonatal units in Bloemfontein, South Africa (SA), from 1 January 2012 - 31 December 2016.

Results

The study population (n=1 426) had a median birthweight of 1 260 g and a median gestation age of 30 weeks. RBCTs were given to 41.9%, and NEC developed in 7.4%, of whom 47.6% had an RBCT (TANEC). Half (47.2%) were kept nil per os (NPO) around the transfusion. No association was found between NPO status and TANEC development (8.9% NPO patients, 7.9% non-NPO patients, p=0.6826). No significant differences regarding Modified Bell's Staging were found between neonates who developed TANEC v. NEC.

Conclusion

Optimising the administration of RBCTs and evidence-based feeding protocols is crucial in reducing TANEC's impact on premature neonates.

Contribution of the study

The study examines the link between red blood cell transfusion and transfusion-associated necrotising enterocolitis in very low birthweight neonates. It highlights the need for evidence-based feeding protocols to reduce transfusion-associated necrotising enterocolitis risk during transfusions. It calls for standardised clinical guidelines to improve neonatal outcomes and lower necrotising enterocolitis and transfusion-associated necrotising enterocolitis incidence.

Banked term umbilical cord blood to meet the packed red blood cell transfusion needs of extremely-low-gestational-age neonates: a feasibility analysis

OBJECTIVES

To assess the feasibility of drawing, processing, safety-testing, and banking term umbilical cord blood to meet the packed red blood cell transfusion (RBC Tx) needs of extremely-low-gestational-age neonates (ELGANs).

DESIGN

(1) Retrospectively analyze all ELGANs RBC Tx over the past three years, (2) Estimate local cord blood availability, (3) Assess interest in this project, and implementation barriers, through stakeholder surveys.

RESULTS

In three years we cared for 266 ELGANs; 165 (62%) received ≥1 RBC Tx. Annual RBC Tx averaged 197 (95% CI, 152-243). If 10% of our 10,353 annual term births had cord blood drawn and processed, and half of those tested were acceptable for Tx, collections would exceed the 95th % upper estimate for need by >four-fold. Interest exceeded 97%. Identified barriers included FDA approval, training to collect cord blood, and cost.

CONCLUSION

RBC Tx needs of ELGANS could be met by local cord blood collection.

Clinical Dilemma Involving Treatments for Very Low-Birth-Weight Infants and the Potential Risk of Necrotizing Enterocolitis: A Narrative Literature Review

Necrotizing enterocolitis (NEC) is a critical gastrointestinal emergency with substantial morbidity and mortality risks, especially for very low-birth-weight (VLBW) infants, and unclear multifactorial pathophysiology. Whether common treatments for VLBW infants increase the NEC risk remains controversial. Indomethacin (utilized for patent ductus arteriosus) offers benefits but is concerning because of its vasoconstrictive impact on NEC susceptibility. Similarly, corticosteroids used to treat bronchopulmonary dysplasia may increase vulnerability to NEC by compromising immunity and altering the mesenteric blood flow. Histamine-2 receptor blockers (used to treat gastric bleeding) may inadvertently promote NEC by affecting bacterial colonization and translocation. Doxapram (used to treat apnea) poses a risk of gastrointestinal disturbance via gastric acid hypersecretion and circulatory changes. Glycerin enemas aid meconium evacuation but disrupt microbial equilibrium and trigger stress-related effects associated with the NEC risk. Prolonged antibiotic use may unintentionally increase the NEC risk. Blood transfusions for anemia can promote NEC via interactions between the immune response and ischemia-reperfusion injury. Probiotics for NEC prevention are associated with concerns regarding sepsis and bacteremia. Amid conflicting evidence, this review unveils NEC risk factors related to treatments for VLBW infants, offers a comprehensive overview of the current research, and guides personalized management strategies, thereby elucidating this clinical dilemma.

Trial-related blood sampling and red blood cell transfusions in preterm infants

AIM

To determine if trial-related blood sampling increases the risk of later red blood cell (RBC) transfusion in very preterm infants, we compared the volume of clinical- and trial-related blood samples, in a specific trial and correlated to subsequent RBC transfusion.

METHODS

For 193 very preterm infants, participating in the FortiColos trial (NCT03537365), trial-related blood volume drawn was in accordance with ethical considerations established by the European Commission. Medical records were reviewed to assess the number and accumulated volume (mL/kg) of blood samples (both clinical- and trial-related). Data were compared with the need of RBC transfusions during the first 28 days of life.

RESULTS

Mean (SD) gestational age and birth weight was 28 ± 1 weeks and 1168 ± 301 g. In total, 11% of total blood volume was drawn for sampling (8.1 ± 5.1 mL/kg) and trial-related sampling accounted for 1.6 ± 0.6 mL/kg. Trial-related blood sampling had no impact on RBC transfusion (p = 0.9).

CONCLUSION

Clinical blood sampling in very preterm infants is associated with blood loss and subsequent need for RBC transfusions. In a specific trial requiring blood samples, we found no additional burden of trial-related blood sampling. The study suggests that trial-related sampling is safe if European criteria are followed.

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.

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.