Anemia induces gut inflammation and injury in an animal model of preterm infants

[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.

Sex differences in the association of pretransfusion haemoglobin and cognition in preterm infants

OBJECTIVES

To assess sex-specific differences in the association between pre-transfusion haemoglobin values and early neurodevelopmental function.

DESIGN

Observational follow-up of infants with birth weights <1000 g and gestational ages 22-28 weeks who were enrolled in the NICHD Neonatal Research Network Transfusion of Prematures (TOP) Trial at 19 U.S. sites, 2012-2017.

MAIN OUTCOME MEASURES

Pretransfusion haemoglobin values were obtained longitudinally through 36 weeks' postmenstrual age. The infant's mean pretransfusion haemoglobin was used as a marker of degree of anaemia (n=1655 measures). Measures of brain function were obtained at 22-26 months' corrected age using the Bayley Scales of Infant & Toddler Development, third edition (BSID-III) (n=1290 BSID-III scores). Sex-specific estimates for the linear relation between pretransfusion haemoglobin and BSID-III scores were obtained from repeated-measures regression analysis, adjusted for gestational age, birth weight, study site, clinical characteristics, and demographic covariates.

RESULTS

The relation of pretransfusion haemoglobin with 24-month BSID-III scores showed significant, independent interactions with both (1) sex (p=0.046) and (2) retinopathy of prematurity (ROP; p=0.004). In 614 males, BSID-III scores were higher by 1.07 points per g/dL (95% CI 1.58 to 4.33; p=0.008), not differing significantly among the three subscales (cognitive, language and motor; p=0.94). In 247 infants with ROP, BSID-III scores were higher by 2.95 points per g/dL (95% CI 0.28 to 1.87; p<0.0001), uniformly across subscales (p=0.73). These associations were non-significant in 676 females (p=0.96) and 1043 infants without ROP (p=0.81).

CONCLUSIONS

This study demonstrates sex-specific associations between mean pretransfusion haemoglobin (a marker of the severity of anaemia throughout the neonatal intensive care unit [NICU] hospitalisation) and early neurodevelopmental function at 22-26 months' corrected age.

Biology of Anemia: A Public Health Perspective

Our goal is to present recent progress in understanding the biological mechanisms underlying anemia from a public health perspective. We describe important advances in understanding common causes of anemia and their interactions, including iron deficiency (ID), lack of other micronutrients, infection, inflammation, and genetic conditions. ID develops if the iron circulating in the blood cannot provide the amounts required for red blood cell production and tissue needs. ID anemia develops as iron-limited red blood cell production fails to maintain the hemoglobin concentration above the threshold used to define anemia. Globally, absolute ID (absent or reduced body iron stores that do not meet the need for iron of an individual but may respond to iron supplementation) contributes to only a limited proportion of anemia. Functional ID (adequate or increased iron stores that cannot meet the need for iron because of the effects of infection or inflammation and does not respond to iron supplementation) is frequently responsible for anemia in low- and middle-income countries. Absolute and functional ID may coexist. We highlight continued improvement in understanding the roles of infections and inflammation in causing a large proportion of anemia. Deficiencies of nutrients other than iron are less common but important in some settings. The importance of genetic conditions as causes of anemia depends upon the specific inherited red blood cell abnormalities and their prevalence in the settings examined. From a public health perspective, each setting has a distinctive composition of components underlying the common causes of anemia. We emphasize the coincidence between regions with a high prevalence of anemia attributed to ID (both absolute and functional), those with endemic infections, and those with widespread genetic conditions affecting red blood cells, especially in sub-Saharan Africa and regions in Asia and Oceania.

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.

Impact of level of neonatal care on phlebotomy and blood transfusion in extremely low birthweight infants: a prospective, multicenter, observational study

Objectives

To explore the level of neonatal care on cumulative phlebotomy loss (cPL) and red cell transfusions in extremely low birthweight [ELBW; birthweight (BW) <1,000 g] infants, up to 40 weeks post-conceptual age (PCA). The secondary objective was to determine the associations between cPL and number of transfusions and between transfusions and hospital outcomes.

Methods

A prospective, comparative, observational study was conducted in two level IV and two level III neonatal intensive care units (NICUs) in Thailand. Daily cPL volume and number of blood tests were recorded. Descriptive data are reported as frequency and percentage for categorical variables and median [25th percentile (P25), 75th percentile (P75)] for continuous data according to the data distribution. A p-value <0.05 was considered statistically significant.

Results

210 ELBW infants were included; 99 and 111 were admitted to level IV and level III NICUs, respectively. Birth weight of level IV infants was lower 780.0 [660.0, 875.0] vs. 865.0 [723.0, 930.0] g; p < 0.001]. Initial group hematocrits were similar (43.1% vs. 44.0%, p = 0.47). cPL for each infant was 28.1 [16.5, 46.4] ml. Level IV infants had more tests (n = 89 [54, 195] vs. 59 [37, 88], p < 0.001). Counterintuitively, there was a lower cPL trend in level IV infants, but this was insignificant (19.6 [12.3, 52.3] vs. 28.9 [19.3, 45.3] ml; p = 0.06). The number of transfusions in both NICUs was similar 4 [2, 6], with a strong correlation between cPL and number of transfusions (r = 0.79, p < 0.001). Transfusions were significantly associated with bronchopulmonary dysplasia [BPD; adjusted RR (95% CI): 2.6 (1.2, 5.3), p = 0.01].

Conclusions

Level IV NICUs conducted more blood tests in ELBW infants without a difference in cPL, and number of transfusions. Cumulative PL correlated with number of transfusions and was associated with BPD risk. Minimizing cPL by point-of-care tests and restrictive transfusion criteria, may reduce need for transfusion.

Identification of clinical factors associated with timing and duration of spontaneous regression of retinopathy of prematurity not requiring treatment

OBJECTIVE

Identify clinical factors that delay or prolong spontaneous regression of retinopathy of prematurity (ROP).

STUDY DESIGN

Secondary analysis of three prospective studies with 76 infants with ROP not requiring treatment, born ≤30 weeks postmenstrual age (PMA) and ≤1500 grams. Outcomes were PMA at greatest severity of ROP (PMA MSROP), at which regression began, at time of complete vascularization (PMA CV), and regression duration. Pearson's correlation coefficients, t-tests, or analyses of variance were calculated.

RESULTS

Increased positive bacterial cultures, hyperglycemia, transfusion volume of platelets and red blood cells and severity of ROP were associated with later PMA MSROP. Positive bacterial cultures, maternal chorioamnionitis, and less iron deficiency were associated with later PMA CV and prolonged regression duration. Slower length gain was associated with later PMA CV. P < 0.05 for all.

CONCLUSIONS

Preterm infants with inflammatory exposures or linear growth impairment may require longer surveillance for ROP resolution and complete vascularization.

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.

[Clinical characteristics and risk factors for early-onset necrotizing enterocolitis in preterm infants with very/extremely low birth weight]

OBJECTIVES

To investigate the clinical characteristics and risk factors for early-onset necrotizing enterocolitis (NEC) in preterm infants with very/extremely low birth weight (VLBW/ELBW).

METHODS

A retrospective analysis was performed on the medical data of 194 VLBW/ELBW preterm infants with NEC who were admitted to Children's Hospital Affiliated to Zhengzhou University from January 2014 to December 2021. These infants were divided into early-onset group (onset in the first two weeks of life; n=62) and late-onset group (onset two weeks after birth; n=132) based on their onset time. The two groups were compared in terms of perinatal conditions, clinical characteristics, laboratory examination results, and clinical outcomes. Sixty-two non-NEC infants with similar gestational age and birth weight who were hospitalized at the same period as these NEC preterm infants were selected as the control group. The risk factors for the development of early-onset NEC were identified using multivariate logistic regression analysis.

RESULTS

Compared with the late-onset group, the early-onset group had significantly higher proportions of infants with 1-minute Apgar score ≤3, stage III NEC, surgical intervention, grade ≥3 intraventricular hemorrhage, apnea, and fever or hypothermia (P<0.05). The multivariate logistic regression analysis showed that feeding intolerance, blood culture-positive early-onset sepsis, severe anemia, and hemodynamically significant patent ductus arteriosus were independent risk factors for the development of early-onset NEC in VLBW/ELBW preterm infants (P<0.05).

CONCLUSIONS

VLBW/ELBW preterm infants with early-onset NEC have more severe conditions compared with those with late-onset NEC. Neonates with feeding intolerance, blood culture-positive early-onset sepsis, severe anemia, or hemodynamically significant patent ductus arteriosus have a higher risk of early-onset NEC.

Severe anaemia, iron deficiency, and susceptibility to invasive bacterial infections

Severe anaemia and invasive bacterial infections remain important causes of hospitalization and death among young African children. The emergence and spread of antimicrobial resistance demand better understanding of bacteraemia risk factors to inform prevention strategies. Epidemiological studies have reported an association between severe anaemia and bacteraemia. In this review, we explore evidence that severe anaemia is associated with increased risk of invasive bacterial infections in young children. We describe mechanisms of iron dysregulation in severe anaemia that might contribute to increased risk and pathogenesis of invasive bacteria, recent advances in knowledge of how iron deficiency and severe anaemia impair immune responses to bacterial infections and vaccines, and the gaps in our understanding of mechanisms underlying severe anaemia, iron deficiency, and the risk of invasive bacterial infections.

Exploring Predictive Risk Factors of Infusion Reactions with First Pertuzumab Administration in HER2-positive Breast Cancer Patients: A Single Institution Experience

Introduction

Pertuzumab and trastuzumab are monoclonal antibodies used for treating HER2-positive breast cancer. These anti-HER2 antibodies may induce infusion reactions (IR), mainly upon first administration. We investigated factors predicting IR in the initial pertuzumab treatment for HER2-positive breast cancer.

Methods

We retrospectively reviewed the medical records of 57 patients who first received pertuzumab-containing treatment in our hospital from January 2014 to February 2021. The frequency of IR during or immediately after pertuzumab administration was examined. We also analyzed patient characteristics that may represent possible risk factors for IR.

Results

The incidence rate of IR was 44% (25/57). Red blood cell count (P < 0.001), hemoglobin (Hb) concentration (P = 0.0011), and hematocrit (P < 0.001) immediately before pertuzumab administration were significantly lower in patients with IR than in those without. In patients with IR, erythrocyte levels immediately before pertuzumab treatment were significantly lower than baseline when having received anthracycline-containing chemotherapy within three months. Logistic regression analysis showed that a decrease in Hb levels was a significant risk factor for IR (log odds ratio = -17). According to the receiver-operating characteristic analysis, a 10% decrease in Hb after anthracycline-containing treatment was the best cut-off value for predicting IR (sensitivity: 88%; specificity: 77%; area under the curve: 0.87).

Conclusions

Our study showed a higher incidence of IR after pertuzumab treatment than in clinical trials. There was a strong association between IR occurrence and erythrocyte levels lower than baseline in the group that received anthracycline-containing chemotherapy immediately before.

Microcytic hypochromic Anemia is a risk factor for postoperative HAEC: A retrospective study

Background

Hirschsprung-associated enterocolitis (HAEC) is a common and life-threatening complication of Hirschsprung's disease (HSCR), which can occur before and after surgery. The aim of this study was to identify the risk factors associated with the development of HAEC.

Methods

We retrospectively reviewed the medical records of HSCR patients admitted to the Children's Hospital of Shanxi Province, China, between January 2011 and August 2021. Diagnosis of HAEC was made using a scoring system with cutoff values ≥4 and included the patient's history, physical examination, and radiological and laboratory findings. The results are shown as frequency (%). The chi-square test was used to analyze a single factor with a significance level of P < 0.05. Logistic regression analysis was used to analyze multiple factors.

Results

A total of 324 patients were included in this study, with 266 males and 58 females. In total, 34.3% (111/324) of patients had HAEC, including 85 males and 26 females; 18.9% (61/324) of patients had preoperative HAEC; and 15.4% (50/324) of patients had postoperative HAEC within one year after surgery. Gender, age at definitive therapy, and feeding methods were not found to be associated with preoperative HAEC in univariate analysis. Respiratory infection was associated with preoperative HAEC (P = 0.00003). No association was found between gender and age at definitive therapy and postoperative HAEC. Postoperative HAEC was associated with microcytic hypochromic anemia (P = 0.00058), preoperative history of HAEC (P = 0.00120), the creation of a preoperative stoma (P = 0.00097), long segment or total colon HSCR (P = 0.00057), and hypoalbuminemia (P = 0.03225). Regression analysis showed that microcytic hypochromic anemia (OR=2.716, 95% CI = 1.418-5.203, P = 0.003), preoperative history of HAEC (OR=2.814, 95% CI = 1.429-5.542, P = 0.003), the creation of a preoperative stoma (OR=2.332, 95% CI = 1.003-5.420, P = 0.049), and long segment or total colon HSCR (OR=2.167, 95% CI = 1.054-4.456, P = 0.035) were associated with postoperative HAEC.

Conclusion

This study revealed that the incidence of preoperative HAEC at our hospital was associated with respiratory infections. In addition, microcytic hypochromic anemia, preoperative history of HAEC, the creation of a preoperative stoma, and long segment or total colon HSCR were risk factors of postoperative HAEC. The most important finding of this study was that microcytic hypochromic anemia was a risk factor for postoperative HAEC, which has been rarely reported. Further studies with larger sample sizes are necessary to confirm these findings.

Hematological changes in neonatal mice with phlebotomy-induced anemia

BACKGROUND

Anemia is a nearly universal diagnosis in preterm infants, caused by phlebotomy, and exacerbated by the underlying erythropoietic immaturity. Newborn infants are exposed to the unique stressor of fetal-to-neonatal transition, which requires significant adaptation ex utero. Accordingly, the preterm infant's response to anemia may alter the ability to confront underlying illness. This study utilized our preclinical mouse model of phlebotomy-induced anemia (PIA) to comprehensively investigate associated hematological changes.

METHODS

C57BL/6 mice were subjected to timed phlebotomy between postnatal days 2--10 to induce severe anemia. Complete blood counts were determined by the Sysmex XT-2000iV analyzer.

RESULTS

Anemic pups showed a gradual reduction of RBC and hemoglobin (Hb) and increased reticulocyte (RET) counts and red cell distribution width (RDW), however, with reduced RET-Hb from postnatal day (P) of 4 onwards. Elevated levels of high fluorescent RET and immature reticulocyte fraction (IRF) were noted in anemic mouse pups, but low and medium fluorescent RET were reduced. Also, the reduction of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were noted in anemic pups. No changes were seen in lymphocytes, but monocytes and neutrophils were significantly elevated from P4-P6.

CONCLUSIONS

PIA in mouse pups is associated with hematological changes that may be exacerbating factors in neonatal diseases.

IMPACT

Anemia is common and often severe in premature infants. Investigation of hematological parameters in settings of preclinical anemia may be an index of therapeutic strategies. Preclinical model evaluating the effects of neonatal anemia on the remainder of complete blood count. Detailed time kinetic phlebotomy-induced anemic mice enable us to study the impact on developmental delays in erythropoiesis and possible strategic intervention. Hematological effects of severe anemia in mice might provide insight on how best to investigate anemia in preterm infants.

Dose- and sex-dependent effects of phlebotomy-induced anemia on the neonatal mouse hippocampal transcriptome

BACKGROUND

Phlebotomy-induced anemia (PIA) is universal and variable in degree among preterm infants and may contribute to neurodevelopmental risk. In mice, PIA causes brain tissue hypoxia, iron deficiency, and long-term sex-dependent neurobehavioral abnormalities. The neuroregulatory molecular pathways disrupted by PIA underlying these effects are unknown.

METHODS

Male and female pups were phlebotomized daily from postnatal day (P)3-P14 via facial venipuncture to target hematocrits of 25% (moderate, mPIA) and 18% (severe, sPIA). P14 hippocampal RNA from non-bled control and PIA mice was sequenced by next-generation sequencing to identify differentially expressed genes (DEGs) that were analyzed using Ingenuity Pathway Analysis.

RESULTS

mPIA females showed the least DEGs (0.5% of &gt;22,000 genes) whereas sPIA females had the most (8.6%), indicating a dose-dependent effect. mPIA and sPIA males showed similar changes in gene expression (5.3% and 4.7%, respectively), indicating a threshold effect at mPIA. The pattern of altered genes induced by PIA indicates sex-specific and anemia-dose-dependent effects with increased pro-inflammation in females and decreased neurodevelopment in males.

CONCLUSION

These gene-expression changes may underlie the reduced recognition memory function in male and abnormal social-cognitive behavior in female adult mice following neonatal PIA. These results parallel clinical studies demonstrating sex-specific behavioral outcomes as a function of neonatal anemia.

IMPACT

Phlebotomy-induced anemia (PIA) in neonatal mice results in an altered hippocampal transcriptome and the severity of changes are dependent upon degree of anemia and sex of neonatal mice. The reported findings provide context to the sex-specific outcomes that have been reported in transfusion threshold clinical trials of preterm infants and therefore may inform treatment strategies that may be based on sex. These data advance the field by showing that consequences of PIA may be based in sex-specific transcriptomic alterations. Such changes may also result from other causes of neonatal anemia that also affect term infants.

Multiomic Profiling of Iron Deficient Infant Monkeys Reveals Alterations in Neurologically Important Biochemicals in Serum and CSF Prior to the Onset of Anemia

BACKGROUND

The effects of iron deficiency (ID) during infancy extend beyond the hematologic compartment and include short- and long-term adverse effects on many tissues including the brain. However, sensitive biomarkers of iron-dependent brain health are lacking in humans.

OBJECTIVE

To determine whether serum and CSF biomarkers of ID-induced metabolic dysfunction are concordant in the pre/early anemic stage of ID prior to anemia in a nonhuman primate model of infantile IDA.

METHODS

Paired serum and CSF specimens were collected from iron-sufficient (IS; n = 12) and ID (n = 7) rhesus infants at 4-months (pre-anemic period) and 6-months of age (anemic). Hematological, metabolomic, and proteomic profiles were generated via HPLC/MS at both time points to discriminate serum bio markers of ID-induced brain metabolic dysfunction.

RESULTS

We identified 227 metabolites and 205 proteins in serum. Abnormalities indicating altered liver function, lipid dysregulation, and increased acute phase reactants were present in ID. In CSF, we measured 210 metabolites and 1,560 proteins with changes in ID infants indicative of metabolomic and proteomic differences indexing disrupted synaptogenesis. Systemic and CSF proteomic and metabolomic changes were present and concurrent in the pre-anemic and anemic periods.

CONCLUSIONS

Multiomic serum and CSF profiling uncovered pathways disrupted by ID in both the pre-anemic and anemic stages of infantile IDA, including evidence for hepatic dysfunction and activation of acute phase response. Parallel changes observed in serum and CSF potentially provide measurable serum biomarkers of ID that reflect at-risk brain processes prior to progression to clinical anemia.

Sex-specific cytokine responses and neurocognitive outcome after blood transfusions in preterm infants

BACKGROUND

The objective of this study was to determine sex-specific differences in inflammatory cytokine responses to red blood cell (RBC) transfusion in preterm infants in the neonatal period and their relationship to later neurocognitive status.

METHODS

Infants with a birth weight <1000 g and gestational age 22-29 weeks were enrolled in the Transfusion of Prematures (TOP) trial. The total number of transfusions was used as a marker of transfusion status. Nineteen cytokines and biomarkers were analyzed from 71 infants longitudinally during the neonatal period. Twenty-six infants completed the Bayley Scales of Infant & Toddler Development, 3rd Edition (Bayley-III) at 12 months' corrected age.

RESULTS

Nine cytokine levels were significantly elevated in proportion to the number of transfusions received. Of those, one cytokine showed a sex-specific finding (p = 0.004): monocyte chemoattractant protein-1, MCP-1, rose substantially in females (8.9% change per additional transfusion), but not in males (-0.8% change). Higher concentrations of MCP-1 exclusively were associated with worse Bayley-III scores: decreased cognitive raw scores (p = 0.0005) and motor scaled scores (p < 0.0001).

CONCLUSIONS

This study provides evidence of a sex-specific difference in the inflammatory response to RBC transfusions during neonatal life, with MCP-1 levels rising only in females and inversely correlating with neurocognitive status at 12 months old.

IMPACT

It is important to understand the risk factors for abnormal neurodevelopment in preterm infants, including anemia and RBC transfusion, in order to improve outcomes and provide potential targets for therapy. Our study investigates and provides the first evidence of sex-specific differences in inflammatory cytokine responses to RBC transfusions in preterm infants in the neonatal period, and their relationship to later cognitive outcomes. This study critically suggests that different transfusion thresholds may have a sex-specific effect on neurodevelopment: females have worse cognitive outcomes with increased number of transfusions, while males have worse outcomes with lower number of transfusions.

Neonatal anemia relates to intestinal injury in preterm infants

BACKGROUND

Anemia is associated with decreased tissue oxygenation in preterm infants and may contribute to developing necrotizing enterocolitis (NEC). We aimed to investigate whether hemoglobin level is associated with intestinal injury, by comparing anemic infants 10 days prior to red blood cell (RBC) transfusion with non-anemic controls.

METHODS

A nested case-control study in which we matched anemic preterms (gestational age (GA) < 32 weeks) with non-anemic controls (1:1), based on GA, birth weight (BW), and postnatal age. We measured urinary intestinal fatty acid-binding protein, I-FABP, marker for intestinal injury, twice weekly. Simultaneously, we assessed splanchnic oxygen saturation (r_sSO₂) and r_sSO₂ variability.

RESULTS

Thirty-six cases and 36 controls were included (median GA 27.6 weeks, BW 1020 grams). Median I-FABP level was higher in cases from 6 days to 24-h before transfusion (median ranging: 4749-8064 pg/ml versus 2194-3751 pg/ml). R_sSO₂ and r_sSO₂ variability were lower in cases than controls shortly before transfusion. Hemoglobin levels correlated negatively with r_sSO₂ and r_sSO₂ variability in cases, and negatively with I-FABP in cases and controls together.

CONCLUSIONS

Urinary I-FABP levels were higher in anemic infants before RBC transfusion than in non-anemic matched controls, suggesting intestinal injury associated with anemia. This may predispose to NEC in some anemic preterm infants.

IMPACT

Anemia is a common comorbidity in preterm infants and may lead to impaired splanchnic oxygen saturation and intestinal tissue hypoxia, a proposed mechanism for NEC. Lower hemoglobin level is associated with higher urinary I-FABP levels, a marker for intestinal injury, both in anemic preterm infants and in cases and controls together. Lower splanchnic oxygen saturation and reduction of its variability are associated with higher urinary I-FABP levels in anemic preterm infants before their first RBC transfusion. These results support the hypothesis that anemia in very preterm infants results in intestinal cell injury, which may precede NEC development in some.

The association of severe anemia, red blood cell transfusion and necrotizing enterocolitis in neonates

Background

The relationship between severe anemia, red blood cell transfusion and Neonatal necrotizing enterocolitis (NEC) remains controversial. The purpose of this study was to determine the association of severe anemia and RBC transfusion with NEC in neonates.

Methods

The clinical characteristics of NEC were observed in 467 infants with different birth weights from January 2012 to July 2020. A 1:1 ratio case-control study was performed in very low birth weight (VLBW) infants. Severe anemia, RBC transfusion, and confounding factors, including maternal and perinatal complications, feeding, and antibiotics administration were collected in both groups. Univariate and multivariate analyses were used to investigate effects on the risk of NEC.

Results

The day of NEC onset and mortality were inversely associated with birth weight. In VLBW infants, adjusting for other factors, severe anemia within 72 h [OR = 2.404, P = 0.016], RBC transfusion within 24 h [OR = 4.905, P = 0.016], within 48 h [OR = 5.587, P = 0.008], and within 72 h [OR = 2.858, P = 0.011] increased the risk of NEC.

Conclusion

Both severe anemia and RBC transfusion appears to increase the risk of NEC in VLBW infants. The early prevention and treatment of anemia, strict evaluation of the indications for transfusion and enhanced monitoring after transfusion is encouraged in the NICU.

Sex differences in adult social, cognitive, and affective behavioral deficits following neonatal phlebotomy-induced anemia in mice

INTRODUCTION

Anemia is common in prematurely born infants due to blood loss resulting from frequent phlebotomies and may contribute to their neurobehavioral deficits. Preclinical models of phlebotomy-induced anemia (PIA) have revealed metabolic and genomic changes in multiple brain structures of young mice, yet the impact of neonatal PIA on early-life and adult behavior has not been assessed.

METHODS

The present study employed a range of behavioral measures in phlebotomized anemic neonatal mice to investigate short- and long-term neurodevelopmental effects. PIA from postnatal (P) days 3 to 14 caused sex-specific changes in social behavior, novelty preference, and anxiety at P17 that persisted into adulthood.

RESULTS

Our preclinical model suggests that PIA may contribute to acute and long-term behavioral and affective deficits and warrants further substantiation of the observed behavioral phenomena in larger samples.

CONCLUSIONS

We conclude that this model is a useful tool for beginning to better understand the lasting effect that early-life PIA might have on the developing brain. The differential impact of PIA on male and female subjects warrants further exploration for the development of appropriately targeted interventions.

Early Postnatal Comprehensive Biomarkers Cannot Identify Extremely Preterm Infants at Risk of Developing Necrotizing Enterocolitis

Background: Necrotizing enterocolitis (NEC) is a fatal disease where current diagnostic tools are insufficient for preventing NEC. Early predictive biomarkers could be beneficial in identifying infants at high risk of developing NEC. Objective: To explore early biomarkers for predicting NEC in extremely preterm infants (EPIs). Methods: Blood samples were collected on day 2 (median 1.7; range 1.5-2.0) from 40 EPI (median 25 gestational weeks; range 22-27): 11 developed NEC and 29 did not (controls). In each infant, 189 inflammatory, oncological, and vascular proteomic biomarkers were quantified through Proximity Extension Assay. Biomarker expression and clinical data were compared between the NEC group and Controls. Based on biomarker differences, controls were sorted automatically into three subgroups (1, 2, and 3) by a two-dimensional hierarchical clustering analysis. Results: None of the biomarkers differed in expression between all controls and the NEC group. Two biomarkers were higher in Control 1, and 16 biomarkers were lower in Control group 2 compared with the NEC group. No biomarker distinguished Control 3 from the NEC group. Perinatal data were similar in the whole population. Conclusions: Early postnatal comprehensive biomarkers do not identify EPIs at risk of developing NEC in our study. Future studies of predictors of NEC should include sequential analysis of comprehensive proteomic markers in large cohorts.

Transfusions and neurodevelopmental outcomes in extremely low gestation neonates enrolled in the PENUT Trial: a randomized clinical trial

BACKGROUND

Outcomes of extremely low gestational age neonates (ELGANs) may be adversely impacted by packed red blood cell (pRBC) transfusions. We investigated the impact of transfusions on neurodevelopmental outcome in the Preterm Erythropoietin (Epo) Neuroprotection (PENUT) Trial population.

METHODS

This is a post hoc analysis of 936 infants 24-0/6 to 27-6/7 weeks' gestation enrolled in the PENUT Trial. Epo 1000 U/kg or placebo was given every 48 h × 6 doses, followed by 400 U/kg or sham injections 3 times a week through 32 weeks postmenstrual age. Six hundred and twenty-eight (315 placebo, 313 Epo) survived and were assessed at 2 years of age. We evaluated associations between BSID-III scores and the number and volume of pRBC transfusions.

RESULTS

Each transfusion was associated with a decrease in mean cognitive score of 0.96 (95% CI of [-1.34, -0.57]), a decrease in mean motor score of 1.51 (-1.91, -1.12), and a decrease in mean language score of 1.10 (-1.54, -0.66). Significant negative associations between BSID-III score and transfusion volume and donor exposure were observed in the placebo group but not in the Epo group.

CONCLUSIONS

Transfusions in ELGANs were associated with worse outcomes. We speculate that strategies to minimize the need for transfusions may improve outcomes.

IMPACT

Transfusion number, volume, and donor exposure in the neonatal period are associated with worse neurodevelopmental (ND) outcome at 2 years of age, as assessed by the Bayley Infant Scales of Development, Third Edition (BSID-III). The impact of neonatal packed red blood cell transfusions on the neurodevelopmental outcome of preterm infants is unknown. We speculate that strategies to minimize the need for transfusions may improve neurodevelopmental outcomes.

How Severe Anaemia Might Influence the Risk of Invasive Bacterial Infections in African Children

Severe anaemia and invasive bacterial infections are common causes of childhood sickness and death in sub-Saharan Africa. Accumulating evidence suggests that severely anaemic African children may have a higher risk of invasive bacterial infections. However, the mechanisms underlying this association remain poorly described. Severe anaemia is characterized by increased haemolysis, erythropoietic drive, gut permeability, and disruption of immune regulatory systems. These pathways are associated with dysregulation of iron homeostasis, including the downregulation of the hepatic hormone hepcidin. Increased haemolysis and low hepcidin levels potentially increase plasma, tissue and intracellular iron levels. Pathogenic bacteria require iron and/or haem to proliferate and have evolved numerous strategies to acquire labile and protein-bound iron/haem. In this review, we discuss how severe anaemia may mediate the risk of invasive bacterial infections through dysregulation of hepcidin and/or iron homeostasis, and potential studies that could be conducted to test this hypothesis.

Erythropoietin prevents necrotizing enterocolitis in very preterm infants: a randomized controlled trial

Background

Necrotizing enterocolitis (NEC) is one of the most severe complications in very preterm infants, but there are currently no accepted methods to prevent NEC. Studies have shown that erythropoietin (EPO) has the potential to prevent NEC or improve outcomes of preterm NEC. This study aimed to determine whether recombinant human EPO (rhEPO) could protect against NEC in very preterm infants.

Methods

The study was a prospective randomized clinical trial performed among four NICU centers. A total of 1327 preterm infants with gestational age ≤ 32 weeks were admitted to the centers, and 42 infants were excluded leaving 1285 eligible infants to be randomized to the rhEPO or control group. Infants in the rhEPO group were given 500 IU/kg rhEPO intravenously every other day for 2 weeks, while the control group was given the same volume of saline. The primary outcome was the incidence of NEC in very preterm infants at 36 weeks of corrected gestational age.

Results

A total of 1285 infants were analyzed at 36 weeks of corrected age for the incidence of NEC. rhEPO treatment significantly decreased the incidence of NEC (stage I, II and III) (12.0% vs. 17.1%, p = 0.010), especially confirmed NEC (stage II and III) (3.0% vs. 5.4%, p = 0.027). Meanwhile, rhEPO treatment significantly reduced the number of red blood cells transfusion in the confirmed NEC cases (1.2 ± 0.4 vs. 2.7 ± 1.0, p = 0.004). Subgroup analyses showed that rhEPO treatment significantly decreased the incidence of confirmed NEC at gestational age < 28 weeks (p = 0.019), and the incidence of all stages NEC in preterm infants with hemoglobin < 90 g/l (p = 0.000) and 5 min Apgar score > 5 (p = 0.028).

Conclusion

Repeated low-dose rhEPO treatment is beneficial against NEC in very preterm infants.

Trial registration The protocol was registered retrospectively at ClinicalTrials.gov (NCT03919500) on April 18, 2019. https://clinicaltrials.gov/ct2/show/NCT03919500

New directions in necrotizing enterocolitis with early-stage investigators

The 2019 Necrotizing Enterocolitis (NEC) Symposium expanded upon the NEC Society's goals of bringing stakeholders together to discuss cutting-edge science, potential therapeutics and preventative measures, as well as the patient-family perspectives of NEC. The Symposium facilitated discussions and shared knowledge with the overarching goal of creating "A World Without NEC." To accomplish this goal, new research to advance the state of the science is necessary. Over the last decade, several established investigators have significantly improved our understanding of the pathophysiology of NEC and they have paved the way for the next generation of clinician-scientists funded to perform NEC research. This article will serve to highlight the contributions of these young clinician-scientists that seek to elucidate how immune, microbial and nervous system dysregulation contributes to the pathophysiology of NEC.

The development of intestinal dysbiosis in anemic preterm infants

OBJECTIVE

Anemia and Proteobacteria-dominant intestinal dysbiosis in very low birth weight (VLBW) infants have been linked to necrotizing enterocolitis, a severe gut inflammatory disease. We hypothesize that anemia of prematurity is related to the development of intestinal dysbiosis.

STUDY DESIGN

Three hundred and forty-two weekly stool samples collected prospectively from 80 VLBW infants were analyzed for bacterial microbiomes (with 16S rRNA). Linear mixed-effects model was used to determine the relationships between the onsets of anemia and intestinal dysbiosis.

RESULTS

Hematocrit was associated with intestinal microbiomes, with lower Hct occurring with increased Proteobacteria and decreased Firmicutes. Infants with a hematocrit <30% had intestinal microbiomes that diverged toward Proteobacteria dominance and low diversity after the first postnatal month. The microbiome changes were also related to the severity of anemia.

CONCLUSIONS

This finding supports a potential microbiological explanation for anemia as a risk factor for intestinal dysbiosis in preterm infants.

Transfusion-related Gut Injury and Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) accounts for 10% of deaths in neonatal intensive care units. Several causal mechanisms are likely to lead to a final common disease phenotype. This article summarizes recent data on NEC following red blood cell (RBC) transfusion, with a focus on the most recent literature and ongoing trials. It highlights potential mechanisms from preclinical and human physiologic studies. It also discusses the role of feeding during RBC transfusion and the risk of NEC. Ongoing randomized trials will provide important data on how liberal or conservative approaches to RBC transfusion influence the risk of NEC.

Red blood cell transfusions alter splanchnic oxygenation response to enteral feeding in preterm infants: an observational pilot study

BACKGROUND

Preterm infants often require red blood cell (RBC) transfusions, which may impair splanchnic hemodynamics, thus predisposing to necrotizing enterocolitis (NEC). The aim of this study was to evaluate whether RBC transfusions alter splanchnic oxygenation patterns in response to enteral feeding in this population.

MATERIALS AND METHODS

Preterm neonates (gestational age < 32 weeks and/or birth weight < 1500 g) requiring RBC transfusions for anemia underwent a 12-hour Near Infrared Spectroscopy monitoring of splanchnic (SrSO₂ ) and cerebral (CrSO₂ ) oxygenation, including the transfusion period, one feed before and one after. Splanchnic-cerebral oxygenation ratio (SCOR) was also calculated. Patterns of CrSO₂ , SrSO₂ , and SCOR changes from baseline (Δ) in response to feed before and after transfusion were analyzed.

RESULTS

Twenty neonates were enrolled; none of them developed any gastrointestinal complication within 48 hours after transfusion. Pre-transfusion ΔSrSO₂ and ΔSCOR increased significantly in response to feeding; on the contrary, a significant post-prandial decrease of ΔSrSO₂ and ΔSCOR occurred after transfusion (p < 0.05). No difference in pre- and post-transfusion ΔCrSO₂ patterns was observed.

CONCLUSIONS

In preterm infants, RBC transfusions may alter splanchnic oxygenation response to enteral feeds. Whether these changes are involved in the pathogenesis of transfusion-associated NEC has to be evaluated in further larger trials.

Neonatal Umbilical Arterial Catheter Removal Is Accompanied by a Marked Decline in Phlebotomy Blood Loss

BACKGROUND

Umbilical arterial catheters (UACs) are frequently used in critically ill neonates. UAC are convenient, reliable, and allow for caregiver convenience in performing painless arterial blood sampling. We hypothesized that UAC removal in extremely low birth weight (ELBW) neonates will result in significantly less phlebotomy blood loss (PBL) after correcting for severity of illness.

STUDY DESIGN AND METHODS

PBL was measured at a single center in 99 ELBW infants who survived to day 28. Individual infant's paired daily PBL for the two 24-h periods before and after UAC removal were compared using the paired t test. Daily PBL up to 7 days before and 7 days after UAC removal were compared using a logistic regression with mixed model analysis for repeated measures. Cumulative 28-day phlebotomy loss was evaluated by multiple linear regression analysis.

RESULTS

PBL 24 h before and after UAC removal were 1.7 mL (95% CI 1.5-1.9) and 0.9 mL (95% CI 0.8-1.0; p < 0.0001), respectively. Cumulative 28-day PBL increased by 2.2 mL (±0.7) per day that a UAC was present with or without correction for severity of illness (p < 0.001).

CONCLUSION

UAC removal is independently associated with a marked decline in PBL. We speculate the ease and convenience of UAC blood sampling lead to more frequent blood testing and greater PBL.